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Find video protocols related to scientific articles indexed in Pubmed.
The kiss/kissr systems are dispensable for zebrafish reproduction: evidence from gene knockout studies.
Endocrinology
PUBLISHED: 11-19-2014
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The kiss1/gpr54 signaling system is considered to be a critical regulator of reproduction in most vertebrates. However this presumption has not been tested vigorously in non-mammalian vertebrates. Distinct from mammals, multiple kiss1/gpr54 paralogous genes (kiss/kissr) have been identified in non-mammalian vertebrates, raising the possibility of functional redundancy among these genes. In this study, we have systematically generated the zebrafish kiss1(-/-), kiss2(-/-) and kiss1(-/-);kiss2(-/-) mutant lines as well as the kissr1(-/-), kissr2(-/-) and kissr1(-/-);kissr2(-/-) mutant lines using transcription activator like effector nucleases (TALENs). We have demonstrated that spermatogenesis and folliculogenesis as well as reproductive capability are not impaired in all of these six mutant lines. Collectively, our results indicate that kiss/kissr signaling is not absolutely required for zebrafish reproduction, suggesting that the kiss/kissr systems play non-essential roles for reproduction in certain non-mammalian vertebrates. These findings also demonstrated that fish and mammals have evolved different strategies for neuroendocrine control of reproduction.
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MicroRNA silencing for cancer therapy targeted to the tumour microenvironment.
Nature
PUBLISHED: 10-02-2014
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MicroRNAs are short non-coding RNAs expressed in different tissue and cell types that suppress the expression of target genes. As such, microRNAs are critical cogs in numerous biological processes, and dysregulated microRNA expression is correlated with many human diseases. Certain microRNAs, called oncomiRs, play a causal role in the onset and maintenance of cancer when overexpressed. Tumours that depend on these microRNAs are said to display oncomiR addiction. Some of the most effective anticancer therapies target oncogenes such as EGFR and HER2; similarly, inhibition of oncomiRs using antisense oligomers (that is, antimiRs) is an evolving therapeutic strategy. However, the in vivo efficacy of current antimiR technologies is hindered by physiological and cellular barriers to delivery into targeted cells. Here we introduce a novel antimiR delivery platform that targets the acidic tumour microenvironment, evades systemic clearance by the liver, and facilitates cell entry via a non-endocytic pathway. We find that the attachment of peptide nucleic acid antimiRs to a peptide with a low pH-induced transmembrane structure (pHLIP) produces a novel construct that could target the tumour microenvironment, transport antimiRs across plasma membranes under acidic conditions such as those found in solid tumours (pH approximately 6), and effectively inhibit the miR-155 oncomiR in a mouse model of lymphoma. This study introduces a new model for using antimiRs as anti-cancer drugs, which can have broad impacts on the field of targeted drug delivery.
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Targeted Gene Disruption in Zebrafish Reveals Noncanonical Functions of LH Signaling in Reproduction.
Mol. Endocrinol.
PUBLISHED: 09-19-2014
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The pivotal role of gonadotropin signaling in regulating gonadal development and functions has attracted much research attention in the past 2 decades. However, the precise physiological role of gonadotropin signaling is still largely unknown in fish. In this study, we have established both LH ?-subunit (lhb) and LH receptor (lhr) knockout zebrafish lines by transcription activator-like effector nucleases. Intriguingly, both homozygous lhb and lhr mutant male fish are fertile. The fertilization rate, sperm motility, and histological structure of the testis were not affected in either lhb or lhr mutant males. On the contrary, homozygous lhb mutant females are infertile, whereas homozygous lhr mutant females are fertile. Folliculogenesis was not affected in either lhb or lhr mutants, but oocyte maturation and ovulation were disrupted in lhb mutant, whereas only ovulation was affected in lhr mutant. Differential expression of genes in the ovary involved in steroidogenesis, oocyte maturation, and ovulation was found between the lhb and lhr mutants. These data demonstrate the essential role of LH signaling in oocyte maturation and ovulation, and support the notion that LH acts through the FSH receptor in the absence of LH receptor. Moreover, the defects of lhb mutant could be partially restored by administration of human chorionic gonadotropin. This in vivo evidence in the present study demonstrates, for the first time in any vertebrate species, that LH signaling is indispensable in female reproduction but not in male reproduction. LH signaling is demonstrated to control oocyte maturation and ovulation in the ovary.
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A Small-Molecule Modulator of the Tumor-Suppressor miR34a Inhibits the Growth of Hepatocellular Carcinoma.
Cancer Res.
PUBLISHED: 09-12-2014
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Small molecules that restore the expression of growth-inhibitory microRNAs (miRNA) downregulated in tumors may have potential as anticancer agents. miR34a functions as a tumor suppressor and is downregulated or silenced commonly in a variety of human cancers, including hepatocellular carcinoma (HCC). In this study, we used an HCC cell-based miR34a luciferase reporter system to screen for miR34a modulators that could exert anticancer activity. One compound identified as a lead candidate, termed Rubone, was identified through its ability to specifically upregulate miR34a in HCC cells. Rubone activated miR34a expression in HCC cells with wild-type or mutated p53 but not in cells with p53 deletions. Notably, Rubone lacked growth-inhibitory effects on nontumorigenic human hepatocytes. In a mouse xenograft model of HCC, Rubone dramatically inhibited tumor growth, exhibiting stronger anti-HCC activity than sorafenib both in vitro and in vivo. Mechanistic investigations showed that Rubone decreased expression of cyclin D1, Bcl-2, and other miR34a target genes and that it enhanced the occupancy of p53 on the miR34a promoter. Taken together, our results offer a preclinical proof of concept for Rubone as a lead candidate for further investigation as a new class of HCC therapeutic based on restoration of miR34a tumor-suppressor function. Cancer Res; 74(21); 6236-47. ©2014 AACR.
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Academy of Medicine-Ministry of Health clinical practice guidelines: attention deficit hyperactivity disorder.
Singapore Med J
PUBLISHED: 09-06-2014
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The Academy of Medicine (AMS) and the Ministry of Health (MOH) have developed the clinical practice guidelines on Attention Deficit Hyperactivity Disorder (ADHD) to provide doctors and patients in Singapore with evidence-based treatment for ADHD. This article reproduces the introduction and executive summary (with recommendations from the guidelines) from the MOH clinical practice guidelines on ADHD, for the information of SMJ readers. Chapters and page numbers mentioned in the reproduced extract refer to the full text of the guidelines, which are available from the Ministry of Health website: http://www.moh.gov.sg/content/moh_web/healthprofessionalsportal/doctors/guidelines/cpg_medical.html.The recommendations should be used with reference to the full text of the guidelines. Following this article are multiple choice questions based on the full text of the guidelines.
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Clinical and Functional Outcomes in Young Adult Males With ADHD.
J Atten Disord
PUBLISHED: 09-04-2014
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To investigate clinical and functional outcomes in military men with ADHD.
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Cellular uptake behaviour, photothermal therapy performance, and cytotoxicity of gold nanorods with various coatings.
Nanoscale
PUBLISHED: 08-27-2014
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With the development of Au nanorods for a number of biomedical applications, understanding their cellular responses has become increasingly important. In this study, we systematically evaluated the cellular uptake behaviour and cytotoxicity of Au nanorods with various surface coatings, including organic cetyltrimethylammonium bromide (CTAB), poly(sodium 4-styrenesulfonate) (PSS), and poly(ethylene glycol) (PEG), and inorganic mesoporous silica (mSiO2), dense silica (dSiO2), and titanium dioxide (TiO2). The cellular behaviour of Au nanorods was found to be highly dependent on both the surface coating and the cell type. CTAB-, PSS-, and mSiO2-coated Au nanorods exhibit notable cytotoxicity, while PEG-, dSiO2-, and TiO2-coated Au nanorods do not induce cell injury. Optical imaging studies indicated that the cell type plays a preferential role in Au nanorod cellular uptake. Higher cellular uptake of Au nanorods was seen in U-87 MG, PC-3, MDA-MB-231, and RAW 264.7 cells, as opposed to HepG2 and HT-29 cells. In addition, Au nanorod cellular uptake is also highly affected by serum protein binding to the surface coating. mSiO2-, dSiO2-, and TiO2-coated Au nanorods show significantly higher cellular uptake than PSS- and PEG-coated ones, which results in a better photothermal ablation effect for Au nanorods with the inorganic surface coatings. Our study provides valuable insights into the effects of the surface modification on the biocompatibility, cellular uptake, as well as biomedical functions of Au nanorods.
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Recent developments in the effects of nitric oxide-donating statins on cardiovascular disease through regulation of tetrahydrobiopterin and nitric oxide.
Vascul. Pharmacol.
PUBLISHED: 08-17-2014
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Since the discovery of the importance of nitric oxide (NO) to the human body three decades ago, numerous laboratory and clinical studies have been done to explore its potential therapeutic actions on many organs. In the cardiovascular system, NO works as a volatile signaling molecule regulating the vascular permeability and vascular tone, preventing thrombosis and inflammation, as well as inhibiting the smooth muscle hyperplasia. Thus, NO is important in the prevention and treatment of cardiovascular disease. NO is synthesized by NO synthase (NOS) with tetrahydrobiopterin (BH4) as the crucial cofactor. Many studies have been done to form nitric oxide donors so as to deliver NO directly to the vessel walls. In addition, NO moieties have been incorporated into existing therapeutic agents to enhance the NO bioavailability, including statins. Statins are inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme (HMG-CoA), the rate-limiting enzyme of the mevalonate pathway. By inhibiting this pathway, statins lower blood cholesterol and exert their pleiotropic effects through activity in reaction cascades, such as Rho/ROCK and Rac 1/NADPH oxidase pathways. Statins have also been observed to implement their non-lipid effects by promoting BH4 synthesis with increase of NO bioavailability. Furthermore, NO-donating statins in laboratory studies have demonstrated to produce better therapeutic effects than their parent's drugs. They offer better anti-inflammatory, anti-proliferative and antithrombotic actions on cardiovascular system. They also cause better revascularization in peripheral ischemia and produce greater enhancement in limb reperfusion and salvage. In addition, it has been shown that NO-donating statin caused less myotoxicity, the most common side effect related to treatment with statins. The initial studies have demonstrated the superior therapeutic effects of NO-donating statins while producing fewer side effects.
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Synergistic tumor suppression by combined inhibition of telomerase and CDKN1A.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 07-14-2014
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Tumor suppressor p53 plays an important role in mediating growth inhibition upon telomere dysfunction. Here, we show that loss of the p53 target gene cyclin-dependent kinase inhibitor 1A (CDKN1A, also known as p21(WAF1/CIP1)) increases apoptosis induction following telomerase inhibition in a variety of cancer cell lines and mouse xenografts. This effect is highly specific to p21, as loss of other checkpoint proteins and CDK inhibitors did not affect apoptosis. In telomerase, inhibited cell loss of p21 leads to E2F1- and p53-mediated transcriptional activation of p53-upregulated modulator of apoptosis, resulting in increased apoptosis. Combined genetic or pharmacological inhibition of telomerase and p21 synergistically suppresses tumor growth. Furthermore, we demonstrate that simultaneous inhibition of telomerase and p21 also suppresses growth of tumors containing mutant p53 following pharmacological restoration of p53 activity. Collectively, our results establish that inactivation of p21 leads to increased apoptosis upon telomerase inhibition and thus identify a genetic vulnerability that can be exploited to treat many human cancers containing either wild-type or mutant p53.
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Mechanistic studies of anti-hyperpigmentary compounds: elucidating their inhibitory and regulatory actions.
Int J Mol Sci
PUBLISHED: 06-29-2014
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Searching for depigmenting agents from natural sources has become a new direction in the cosmetic industry as natural products are generally perceived as relatively safer. In our previous study, selected Chinese medicines traditionally used to treat hyperpigmentation were tested for anti-hyperpigmentary effects using a melan-a cell culture model. Among the tested chemical compounds, 4-ethylresorcinol, 4-ethylphenol and 1-tetradecanol were found to possess hypopigmentary effects. Western blot analysis, reverse transcriptase polymerase chain reaction (RT-PCR), cyclic adenosine monophosphate (cAMP) assay, protein kinase A (PKA) activity assay, tyrosinase inhibition assay and lipid peroxidation inhibition assay were performed to reveal the underlying cellular and molecular mechanisms of the hypopigmentary effects. 4-Ethylresorcinol and 4-ethylphenol attenuated mRNA and protein expression of tyrosinase-related protein (TRP)-2, and possessed antioxidative effect by inhibiting lipid peroxidation. 1-Tetradecanol was able to attenuate protein expression of tyrosinase. The hypopigmentary actions of 4-ethylresorcinol, 4-ethylphenol and 1-tetradecanol were associated with regulating downstream proteins along the PKA pathway. 4-Ethylresorcinol was more effective in inhibiting melanin synthesis when compared to 4-ethylphenol and 1-tetradecanol.
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Silencing of EEF2K (eukaryotic elongation factor-2 kinase) reveals AMPK-ULK1-dependent autophagy in colon cancer cells.
Autophagy
PUBLISHED: 06-19-2014
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EEF2K (eukaryotic elongation factor-2 kinase), also known as Ca (2+)/calmodulin-dependent protein kinase III, functions in downregulating peptide chain elongation through inactivation of EEF2 (eukaryotic translation elongation factor 2). Currently, there is a limited amount of information on the promotion of autophagic survival by EEF2K in breast and glioblastoma cell lines. However, the precise role of EEF2K in carcinogenesis as well as the underlying mechanism involved is still poorly understood. In this study, contrary to the reported autophagy-promoting activity of EEF2K in certain cancer cells, EEF2K is shown to negatively regulate autophagy in human colon cancer cells as indicated by the increase of LC3-II levels, the accumulation of LC3 dots per cell, and the promotion of autophagic flux in EEF2K knockdown cells. EEF2K negatively regulates cell viability, clonogenicity, cell proliferation, and cell size in colon cancer cells. Autophagy induced by EEF2K silencing promotes cell survival and does not potentiate the anticancer efficacy of the AKT inhibitor MK-2206. In addition, autophagy induced by silencing of EEF2K is attributed to induction of protein synthesis and activation of the AMPK-ULK1 pathway, independent of the suppression of MTOR activity and ROS generation. Knockdown of AMPK or ULK1 significantly abrogates EEF2K silencing-induced increase of LC3-II levels, accumulation of LC3 dots per cell as well as cell proliferation in colon cancer cells. In conclusion, silencing of EEF2K promotes autophagic survival via activation of the AMPK-ULK1 pathway in colon cancer cells. This finding suggests that upregulation of EEF2K activity may constitute a novel approach for the treatment of human colon cancer.
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Methods for characterizing human coronary artery deformation from cardiac-gated computed tomography data.
IEEE Trans Biomed Eng
PUBLISHED: 05-13-2014
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Accurate quantification of changes in length, curvature, and bifurcation angles of coronary arteries due to cardiac motion is important for the design of coronary stents. A new method is developed to describe the dynamic characteristics of the human coronary artery. From cardiac-gated computed tomography (CT) data, 3-D surface geometry and centerline paths of the coronary arteries were constructed. For quantification of strain and twisting deformation, 3-D distortion-free vessel straightening and landmark matching algorithms were developed to compute the relative translation and rotation of distal landmarks with respect to a proximal landmark. For quantification of bending deformation, change in curvature was measured by computing a best-fit torus in the region of interest within a coronary segment. The optimal torus parameters were estimated by minimizing the standard deviation of distances from the surface mesh to the centerline of the torus. The angle between branch vessels was measured using linear fitting of centroid sets from the cross-sectional vessel lumen. The proposed methods were verified using a software phantom and applied to two patient specific CT datasets. Vascular deformations derived from these methods can provide information for designing bench-top tests for endovascular devices that better replicate the in vivo environment, thereby improving device performance prediction and leading to more durable designs.
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Ginsenosides attenuate methylglyoxal-induced impairment of insulin signaling and subsequent apoptosis in primary astrocytes.
Neuropharmacology
PUBLISHED: 04-10-2014
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Diabetes mellitus (DM), which is characterized by chronic hyperglycemia, is known to increase the risk of neurodegeneration. In type 2 diabetes, hyperglycemia could cause insulin resistance and neurodegeneration in various cells including neurons and astrocytes. Hyperglycemia is also known to result in the formation of advanced glycation end-products (AGE) Methylglyoxal (MG) is one of the most reactive AGE precursors in which its abnormal accumulation is usually found in diabetic patients and induces neuronal cell death in central nervous system. Ginseng is a herb that has been widely used to treat various diseases in traditional Chinese medicine. Ginsenosides, the pharmacologically active component isolated from ginseng, have been shown to have cryoprotective effects in different neural cells. In the present study we investigated the effects of MG in disturbing insulin signaling and leading to further cellular apoptosis in rat primary astrocytes. Furthermore, the protective effects of different subtypes of ginsenosides were studied. From the results, impairment of insulin signaling was found in astrocytes under MG treatment. Moreover, cleavage of caspase and Poly ADP ribose polymerase (PARP) was observed in line with insulin signaling disruption, showing the neurotoxic effects of MG towards astrocytes. The effects of ginsenosides in MG treated astrocytes were also investigated. After treatment, ginsenosides Rd and R-Rh2 were shown to ameliorate the cell viability of MG-treated astrocytes. In addition, Rd and R-Rh2 could improve insulin signaling and inhibit apoptosis, indicating that Rd, R-Rh2 and related compounds may have therapeutic potential in treating diabetes-induced neurodegeneration.
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Isorhynchophylline improves learning and memory impairments induced by D-galactose in mice.
Neurochem. Int.
PUBLISHED: 04-08-2014
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Isorhynchophylline (IRN), an alkaloid isolated from Uncaria rhynchophylla, has been reported to improve cognitive impairment induced by beta-amyloid in rats. However, whether IRN could also ameliorate the D-galactose (D-gal)-induced mouse memory deficits is still not clear. In the present study, we aimed to investigate whether IRN had potential protective effect against the D-gal-induced cognitive deficits in mice. Mice were given a subcutaneous injection of D-gal (100mg/kg) and orally administered IRN (20 or 40mg/kg) daily for 8weeks, followed by assessing spatial learning and memory function by the Morris water maze test. The results showed that IRN significantly improved spatial learning and memory function in the D-gal-treated mice. In the mechanistic studies, IRN significantly increased the level of glutathione (GSH) and the activities of superoxide dismutase (SOD) and catalase (CAT), while decreased the level of malondialdehyde (MDA) in the brain tissues of the D-gal-treated mice. Moreover, IRN (20 or 40mg/kg) significantly inhibited the production of prostaglandin E 2 (PGE2) and nitric oxide (NO), and the mRNA expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS), as well as the activation of nuclear factor kappa B (NF-?B) in the brain tissues of D-gal-treated mice. Our results amply demonstrated that IRN was able to ameliorate cognitive deficits induced by D-gal in mice, and the observed cognition-improving action may be mediated, at least in part, through enhancing the antioxidant status and anti-inflammatory effect of brain tissues via NF?B signaling.
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Frontolimbic brain networks predict depressive symptoms in temporal lobe epilepsy.
Epilepsy Res.
PUBLISHED: 03-03-2014
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Psychiatric co-morbidities in epilepsy are of great concern. The current study investigated the relative contribution of structural and functional connectivity (FC) between medial temporal (MT) and prefrontal regions in predicting levels of depressive symptoms in patients with temporal lobe epilepsy (TLE). Twenty-one patients with TLE [11 left TLE (LTLE); 10 right TLE (RTLE)] and 20 controls participated. Diffusion tensor imaging was performed to obtain fractional anisotropy (FA) of the uncinate fasciculus (UF), and mean diffusivity (MD) of the amygdala (AM) and hippocampus (HC). Functional MRI was performed to obtain FC strengths between the AM and HC and prefrontal regions of interest including anterior prefrontal (APF), orbitofrontal, and inferior frontal regions. Participants self-reported depression symptoms on the Beck Depression Inventory-II. Greater depressive symptoms were associated with stronger FC of ipsilateral HC-APF, lower FA of the bilateral UF, and higher MD of the ipsilateral HC in LTLE, and with lower FA of the contralateral UF in RTLE. Regression analyses indicated that FC of the ipsilateral HC-APF was the strongest contributor to depression in LTLE, explaining 68.7% of the variance in depression scores. Both functional and microstructural measures of frontolimbic dysfunction were associated with depressive symptoms. These connectivity variables may be moderating which patients present with depression symptoms. In particular, FC MRI may provide a more sensitive measure of depression-related dysfunction, at least in patients with LTLE. Employing sensitive measures of frontolimbic network dysfunction in TLE may help provide new insight into mood disorders in epilepsy that could eventually guide treatment planning.
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Percutaneous transluminal angioplasty of transplant renal artery stenosis.
Ann. Acad. Med. Singap.
PUBLISHED: 02-22-2014
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Introduction: This study aimed to assess the outcome of percutaneous transluminal angioplasty (PTA) as the primary treatment for transplant renal artery stenosis (TxRAS). Materials and Methods: A retrospective review of PTA of TxRAS from April 1999 to December 2008 was performed. Twenty-seven patients (17 males (M):10 females (F)) with the mean age of 49.5 years underwent PTA of TxRAS in the review period. Indications for PTA were suboptimal control of hypertension (n = 12), impaired renal function (n = 6) and both suboptimal control of hypertension and impaired renal function (n = 9). All patients had doppler ultrasound scans prior to their PTA. In addition, 5 of these patients had computed tomography angiography (CTA) and another 7 had magnetic resonance angiography (MRA) evaluation. Mean follow-up period was 57.0 months (range, 7 to 108 months). Results: The stenotic lesions were located proximal to the anastomosis (n = 2), at the anastomosis (n = 15), and distal to the anastomosis (n = 14). Technical success rate was 96.3%. One case was complicated by extensive dissection during PTA, resulting in subsequent graft failure. The overall clinical success rate was 76.9%. Seven out of 26 patients had restenoses (26.9% of cases). These were detected at a mean of 14.3 months post angioplasty (range, 5 to 38 months). All 7 patients underwent a second PTA successfully. Three of these patients required more than 1 repeat PTA. Conclusion: PTA is safe and effective in the management of symptomatic TxRAS and should be the primary treatment of choice. Close surveillance for restenosis is required and when diagnosed, re-angioplasty can be performed.
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Temporal and spatial expression of the four Igf ligands and two Igf type 1 receptors in zebrafish during early embryonic development.
Gene Expr. Patterns
PUBLISHED: 02-07-2014
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The insulin-like growth factor (Igf) family is an evolutionarily conserved system essential for normal growth and development in vertebrates. Unlike mammals, four distinct Igf ligands (Igf1, Igf2a, Igf2b and Igf3) and two Igf type 1 receptors (Igf1ra and Igf1rb) are present in zebrafish. However, the localization of these multiple ligands and receptors especially the recently discovered igf3 during early development of zebrafish is poorly understood. In this study, detailed expression patterns of these components of the Igf system during embryogenesis of zebrafish were analyzed. It was found that igf1 is specifically expressed in the trigeminal ganglia region from 18 hpf to 72 hpf, while igf2a is restricted to the caudal regions of the notochord from 14 hpf to 18 hpf as well as in the midbrain, dorsal hind brain and otic vesicle at 24 hpf. On the other hand, igf2a is highly expressed in the midbrain and pharyngeal arch region at 48 hpf, followed by its appearance in the liver and brain at 72 hpf, while igf2b is restricted to the floor plate and hypochord from 12 hpf to 18 hpf, and strong expression is also detected in the midbrain and dorsal hind brain at 24 hpf. The teleost specific igf3 is highly expressed in the pharyngeal arch region before 24 hpf, but is then restricted to the sternohyoideus after 48 hpf. The receptor subtype igf1ra is ubiquitously expressed before 24 hpf but is confined to the brain at 72 hpf. However, igf1rb is widely expressed before 10 hpf, but is more confined to the brain region at 24 hpf and 72 hpf. This dynamic temporal-spatial expression during embryogenesis of zebrafish, together with the unique and overlapping expression patterns of the Igf ligands and receptors suggest the coordination of the divergent functions of the Igf system during early development in zebrafish.
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In vivo chemoembolization and magnetic resonance imaging of liver tumors by using iron oxide nanoshell/doxorubicin/poly(vinyl alcohol) hybrid composites.
Angew. Chem. Int. Ed. Engl.
PUBLISHED: 02-07-2014
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A hybrid composite made up of superparamagnetic iron oxide nanoshells encapsulating the anticancer drug doxorubicin and bound together by poly(vinyl alcohol) was developed. Transcatheter arterial delivery in an in?vivo liver tumor model led to embolization of the liver tumor blood vessels. Embolization was followed by disassembly of the composite. The nanoshells were then able to pass through the leaky tumor vasculature into the tumor tissue, thereby leading to slow and sustained release of the drug. As well as being relatively noncytotoxic, the composite was responsive to magnetic resonance imaging, thus making it a potentially useful theranostic agent.
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Aortic Arch Vessel Geometries and Deformations in Patients with Thoracic Aortic Aneurysms and Dissections.
J Vasc Interv Radiol
PUBLISHED: 02-03-2014
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To quantify aortic arch geometry and in vivo cardiac-induced and respiratory-induced arch translations and arch branch angulations using three-dimensional geometric modeling techniques.
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A highly effective TALEN-mediated approach for targeted gene disruption in Xenopus tropicalis and zebrafish.
Methods
PUBLISHED: 01-17-2014
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Transcription activator like effector nucleases (TALENs) is a promising approach to disrupt intended genomic loci. The assembly of highly effective TALENs is critical for successful genome editing. Recently we reported a convenient and robust platform to construct customized TALENs. The TALENs generated by this platform have been proven to be highly effective for gene disruption in Xenopus tropicalis and zebrafish as well as large genomic deletions in zebrafish. The one-time success rate of targeted gene disruption is about 90% for more than 100 genomic loci tested, with the mutation frequencies often reaching above 50%. Here we describe the validated protocol for TALEN assembly, methods for generating gene knockout animals in X. tropicalis and zebrafish, as well as the protocol for engineering large genomic deletions in zebrafish.
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HLA-C locus allelic dropout in Sanger sequence-based typing due to intronic single nucleotide polymorphism.
Hum. Immunol.
PUBLISHED: 01-07-2014
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We report a novel HLA-C allele that was identified during routine HLA typing using sequence-based methods. The patient was initially typed as a C?06:02, 06:04 with two nucleotide mismatches in exon 3, (C to T and T to G changes) which would have resulted in a non-synonymous mutation of a leucine residue being replaced with tryptophan. Further resolution of the patient's type by using sequence-specific primers (SSP) revealed that the companion allele to C?06:02 was a novel C?17:01. Confirmation of the existence of the new allele was performed across multiple platforms: Sanger sequencing, SSP, and Next Generation Sequencing (NGS) on the original sample and allele-specific clones for the entire HLA-C locus. The investigation revealed a single nucleotide mismatch within the Sanger sequencing primer binding site in intron 3. The mutation caused the initial C?17 dropout in exons 2 and 3. Further analysis of the Sanger and NGS data revealed that the C?17 had two additional unique positions in introns 2 and 7. The companion C?06:02 allele also possessed a novel position at intron 3. On August 31, 2013, the WHO nomenclature committee officially named the novel C?17:01 allele sequence as C?17:01:01:03 and the novel C?06:02 allele sequence as C?06:02:01:03.
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Prevailing attitudes towards cancer: a multicultural survey in a tertiary outpatient setting.
Ann. Acad. Med. Singap.
PUBLISHED: 11-21-2013
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Introduction: Cultural influences affect attitudes towards cancer screening, diagnosis, treatment and palliation. The objective of this study is to survey the prevailing attitudes towards cancer in a multicultural tertiary outpatient setting. Materials and Methods: This is a cross-sectional study of 300 respondents visiting the Singapore General Hospital (SGH) Urology Centre over a period of 1 month. A questionnaire was developed assessing responses to various facets of cancer management and administered in English, Chinese or Malay to every 10th person visiting the centre. Institutional review board approval was obtained. Results: Of 300 respondents, 57% were Chinese, 17% Malay, 19% Indian, and 7% others. Mean age was 54.3 years. Most respondents were male (68%) and had up to secondary education (56%). Most Chinese were Taoist/Buddhist (42%) or Christian/ Catholic (36%) while Indians were largely Hindu (47%) or Muslim (27%). Thirty-seven percent of respondents had ever participated in cancer screening. Eighty-nine percent of respondents wanted to be the first to know if they had cancer, and 76% found it unacceptable if the diagnosis of cancer was withheld from them. These were irrespective of race, religion or other factors. Forty percent of respondents believed that being diagnosed with cancer was a matter of fate. Sixty percent of respondents would undergo treatment with 50% chance of cure, even if it involved major surgery and adjuvant therapy. Eighty-one percent believed in efficacy of at least 1 form of alternative treatment. Seventy-one percent of respondents preferred to die at home and this was most marked among Malay respondents (90.4%). Conclusion: This better understanding of patient attitudes will allow us to help patients balance wishes for autonomy versus family involvement in dealing with cancer. This will help us achieve a more holistic and patient-centred approach to cancer care.
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Sustained delivery of proangiogenic microRNA-132 by nanoparticle transfection improves endothelial cell transplantation.
FASEB J.
PUBLISHED: 11-12-2013
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Transplantation of endothelial cells (ECs) for therapeutic vascularization or tissue engineering is a promising method for increasing tissue perfusion. Here, we report on a new approach for enhanced EC transplantation using targeted nanoparticle transfection to deliver proangiogenic microRNA-132 (miR-132) to cultured ECs before their transplantation, thereby sensitizing cells to the effects of endogenous growth factors. We synthesized biodegradable PLGA polymer nanoparticles (NPs) that were loaded with miR-132 and coated with cyclic RGD (cRGD) peptides that target integrin ?v?3 expressed on cultured human umbilical vein ECs (HUVECs), increasing NP uptake through clathrin-coated pits. Unlike previously reported NPs for miR delivery, these NPs slowly release RNA for several weeks. The endocytosed NPs remain in clathrin-coated vesicles from which they mediate intracellular delivery of siRNA or miRNA. Transfection of HUVECs with miR-132 enhances growth factor-induced proliferation and migration in 2D culture, producing a 1.8- and 5-fold increase, respectively. However, while the effects of conventional transfection were short-lived, NP transfection produced protein knockdown and biological effects that were significantly longer in duration (?6 d). Transfection of HUVECs with miR-132 NP resulted in a 2-fold increase in the number of microvessels per square millimeter compared to lipid after transplantation into immunodeficient mice and led to a higher number of mural cell-invested vessels than control transfection. These data suggest that sustained delivery of miR-132 encapsulated in a targeted biodegradable polymer NP is a safe and efficient strategy to improve EC transplantation and vascularization.-Devalliere, J., Chang, W. G., Andrejecsk, J. W., Abrahimi, P., Cheng, C. J., Jane-wit, D., Saltzman, W. M., Pober, J. S. Sustained delivery of proangiogenic microRNA-132 by nanoparticle transfection improves endothelial cell transplantation.
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Type III-B rotaxane dendrimers.
Chem. Commun. (Camb.)
PUBLISHED: 10-02-2013
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Type III-B first generation [3]rotaxane and second generation [4]rotaxane dendrimers have been synthesized via (1) a modified copper-catalyzed alkyne-azide cycloaddition (CuAAC), (2) Glaser-Hays acetylenic oxidative homo-coupling, and (3) amide formation. The dendron does not reveal obvious cytotoxicities in L929 fibroblast cells. The rotaxane dendrimers can capture ammonia and are switchable both in solution and on surfaces.
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Alterations in functional connectivity between the hippocampus and prefrontal cortex as a correlate of depressive symptoms in temporal lobe epilepsy.
Epilepsy Behav
PUBLISHED: 07-11-2013
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Depression is a common comorbidity in temporal lobe epilepsy (TLE) that is thought to have a neurobiological basis. This study investigated the functional connectivity (FC) of medial temporal networks in depression symptomatology of TLE and the relative contribution of structural versus FC measures. Volumetric MRI and functional connectivity MRI (fcMRI) were performed on nineteen patients with TLE and 20 controls. The hippocampi and amygdalae were selected as seeds, and five prefrontal and five cingulate regions of interest (ROIs) were selected as targets. Low-frequency blood-oxygen-level-dependent signals were isolated from fcMRI data, and ROIs with synchronous signal fluctuations with the seeds were identified. Depressive symptoms were measured by the Beck Depression Inventory-II. The patients with TLE showed greater ipsilateral hippocampal atrophy (HA) and reduced FC between the ipsilateral hippocampus and the ventral posterior cingulate cortex (vPCC). Neither HA nor hippocampal-vPCC FC asymmetry was a robust contributor to depressive symptoms. Rather, hippocampal-anterior prefrontal FC was a stronger contributor to depressive symptoms in left TLE (LTLE). Conversely, right amygdala FC was correlated with depressive symptoms in both patient groups, with a positive and negative correlation in LTLE and right TLE (RTLE), respectively. Frontolimbic network dysfunction is a strong contributor to levels of depressive symptoms in TLE and a better contributor than HA in LTLE. In addition, the right amygdala may play a role in depression symptomatology regardless of the side of the epileptogenic focus. These findings may inform the treatment of depressive symptoms in TLE and inspire future research to help guide surgical planning.
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Viral and paraneoplastic encephalitis in a patient with liver transplant with unilateral temporoparietal lobe abnormalities: a diagnostic challenge.
BMJ Case Rep
PUBLISHED: 06-05-2013
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We report a patient who recently had a liver transplant presented with increasing confusion and intermittent hallucinations. MRI of the brain revealed diffuse left temporal and parietal lobe swelling with cortical diffusion restriction suggestive of possible infectious aetiology, although stroke was also possible given the presence of left posterior cerebral arteries with fetal origin in the anterior circulation. An EEG demonstrated subclinical seizures, for which he was placed on an antiepileptic medication. Routine laboratory testing, lumbar puncture, serum and cerebrospinal fluid testing for viral and paraneoplastic encephalitis, and brain biopsy were performed on our patient. Our clinical diagnosis was viral encephalitis, and positive N-type voltage-gated calcium channel antibody titres were suggestive of paraneoplastic limbic encephalitis. Treatment with antiviral and antiepileptic medications for subclinical seizures resulted in the improvement of his mental status, language output and motor functioning.
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Vascularisation of urethral repairs with the gracilis muscle flap.
Arch Plast Surg
PUBLISHED: 06-03-2013
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The ability to achieve a long-term, stricture-free urethral repair is one of the ongoing challenges of reconstructive urologic surgery. A successful initial repair is critical, as repeat procedures are difficult, owing to distortion, scarring, and short urethral stumps.
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Occurrence of a lymphocele following renal transplantation.
Singapore Med J
PUBLISHED: 05-30-2013
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The incidence of lymphoceles - lymphatic collections around a transplanted kidney - can be as high as 20%. We aimed to review the presentation, treatment and outcome of patients with lymphoceles.
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Nanoparticle-DNA-polymer composites for hepatocellular carcinoma cell labeling, sensing, and magnetic resonance imaging.
Methods
PUBLISHED: 05-28-2013
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This paper describes comparative studies and protocols in (1) self-assembling of ultrasmall superparamagnetic iron oxide nanoparticle (NP), circular plasmid DNA, and branched polyethylenimine (PEI) composites; (2) magnetofection; (3) gene delivery, (4) magnetic resonance imaging (MRI), and (5) cytotoxicity of the composites toward hepatocellular carcinoma HepG2 cells.
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Regeneration of mammalian cochlear and vestibular hair cells through Hes1/Hes5 modulation with siRNA.
Hear. Res.
PUBLISHED: 05-16-2013
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The Notch pathway is a cell signaling pathway determining initial specification and subsequent cell fate in the inner ear. Previous studies have suggested that new hair cells (HCs) can be regenerated in the inner ear by manipulating the Notch pathway. In the present study, delivery of siRNA to Hes1 and Hes5 using a transfection reagent or siRNA to Hes1 encapsulated within poly(lactide-co-glycolide acid) (PLGA) nanoparticles increased HC numbers in non-toxin treated organotypic cultures of cochleae and maculae of postnatal day 3 mouse pups. An increase in HCs was also observed in cultured cochleae and maculae of mouse pups pre-conditioned with a HC toxin (4-hydroxy-2-nonenal or neomycin) and then treated with the various siRNA formulations. Treating cochleae with siRNA to Hes1 associated with a transfection reagent or siRNA to Hes1 delivered by PLGA nanoparticles decreased Hes1 mRNA and up-regulated Atoh1 mRNA expression allowing supporting cells (SCs) to acquire a HC fate. Experiments using cochleae and maculae of p27(kip1)/-GFP transgenic mouse pups demonstrated that newly generated HCs trans-differentiated from SCs. Furthermore, PLGA nanoparticles are non-toxic to inner ear tissue, readily taken up by cells within the tissue of interest, and present a synthetic delivery system that is a safe alternative to viral vectors. These results indicate that when delivered using a suitable vehicle, Hes siRNAs are potential therapeutic molecules that may have the capacity to regenerate new HCs in the inner ear and possibly restore human hearing and balance function.
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Cardiac glycosides block cancer growth through HIF-1?- and NF-?B-mediated Plk1.
Carcinogenesis
PUBLISHED: 04-24-2013
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Cardiac glycosides as inhibitors of the sodium/potassium adenosine triphosphatase (sodium pump) have been reported to block cancer growth by inducing G2/M phase arrest in many cancer cells. However, no detailed studies have been performed to distinguish between these two phases of cardiac glycoside-arrested cells. Furthermore, the underlying mechanisms involved in this cell cycle arrest process are still not known. Here, we report that bufalin and other cardiac glycosides potently induce mitotic arrest by the downregulation of polo-like kinase 1 (Plk1) expression. Live-cell imaging results demonstrate that bufalin-treated cells exhibit a marked delay in entering prophase at an early stage and are then arrested at prometaphase or induced entry into apoptosis. This phenotypic change is attributed to the downregulation of Plk1. We also show that bufalin and the knockdown of sodium pump reduce Plk1, at least in part, through downregulation of the nuclear transcription factors, hypoxia-inducible factor-1? (HIF-1?) and nuclear factor-kappa B (NF-?B). These findings suggest that cardiac glycosides induce mitotic arrest and apoptosis through HIF-1?- and NF-?B-mediated downregulation of Plk1 expression, demonstrating that HIF-1? and NF-?B are critical targets of cardiac glycosides in exerting their anticancer action.
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Modulation of endoplasmic reticulum chaperone GRP78 by high glucose in hippocampus of streptozotocin-induced diabetic mice and C6 astrocytic cells.
Neurochem. Int.
PUBLISHED: 04-12-2013
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Diabetes mellitus is known to increase the risk of neurodegeneration, and both diseases are reported to be linked to dysfunction of endoplasmic reticulum (ER). Astrocytes are important in the defense mechanism of central nervous system (CNS), with great ability of tolerating accumulation of toxic substances and sensitivity in Ca(2+) homeostasis which are two key functions of ER. Here, we investigated the modulation of the glucose-regulated protein 78 (GRP78) in streptozotocin (STZ)-induced diabetic mice and C6 cells cultured in high glucose condition. Our results showed that more reactive astrocytes were presented in the hippocampus of STZ-induced diabetic mice. Simultaneously, decrease of GRP78 expression was found in the astrocytes of diabetic mice hippocampus. In in vitro study, C6 cells were treated with high glucose to investigate the role of high glucose in GRP78 modulation in astrocytic cells. GRP78 as well as other chaperones like GRP94, calreticulin and calnexin, transcription levels were down-regulated after high glucose treatment. Also C6 cells challenged with 48h high glucose were activated, as indicated by increased level of glial fibrillary acidic protein (GFAP). Activated C6 cells simultaneously exhibited significant decrease of GRP78 level and was followed by reduced phosphorylation of Akt. Moreover, unfolded protein response was induced as an early event, which was marked by the induction of CHOP with high glucose treatment, followed by the reduction of GRP78 after 48h. Finally, the upsurge of ROS production was found in high glucose treated C6 cells and chelation of ROS could partially restore the GRP78 expression. Taken together, these data provide evidences that high glucose induced astrocytic activation in both in vivo and in vitro diabetic models, in which modulation of GRP78 would be an important event in this activation.
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Nanoparticles for urothelium penetration and delivery of the histone deacetylase inhibitor belinostat for treatment of bladder cancer.
Nanomedicine
PUBLISHED: 04-04-2013
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Nearly 40% of patients with non-invasive bladder cancer will progress to invasive disease despite locally-directed therapy. Overcoming the bladder permeability barrier (BPB) is a challenge for intravesical drug delivery. Using the fluorophore coumarin (C6), we synthesized C6-loaded poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs), which were surface modified with a novel cell penetrating polymer, poly(guanidinium oxanorbornene) (PGON). Addition of PGON to the NP surface improved tissue penetration by 10-fold in intravesically-treated mouse bladder and ex vivo human ureter. In addition, NP-C6-PGON significantly enhanced intracellular uptake of NPs compared to NPs without PGON. To examine biological activity, we synthesized NPs that were loaded with the histone deacetylase (HDAC) inhibitor belinostat (NP-Bel-PGON). NP-Bel-PGON exhibited a significantly lower IC50 in cultured bladder cancer cells, and sustained hyperacetylation, when compared to unencapsulated belinostat. Xenograft tumors treated with NP-Bel-PGON showed a 70% reduction in volume, and a 2.5-fold higher intratumoral acetyl-H4, when compared to tumors treated with unloaded NP-PGON.
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Leukocyte DNA damage and wound infection after nitrous oxide administration: a randomized controlled trial.
Anesthesiology
PUBLISHED: 04-04-2013
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Nitrous oxide inactivates methionine synthase and may lead to DNA damage and wound infection. By using single-cell gel electrophoresis (comet assay), the authors determined the effect of nitrous oxide on DNA damage in circulating leukocytes.
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Respiration-induced deformations of the superior mesenteric and renal arteries in patients with abdominal aortic aneurysms.
J Vasc Interv Radiol
PUBLISHED: 04-01-2013
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To quantify respiration-induced deformations of the superior mesenteric artery (SMA), left renal artery (LRA), and right renal artery (RRA) in patients with small abdominal aortic aneurysms (AAAs).
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G-protein-coupled estrogen receptor 1 is involved in brain development during zebrafish (Danio rerio) embryogenesis.
Biochem. Biophys. Res. Commun.
PUBLISHED: 03-18-2013
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G-protein-coupled estrogen receptor 1 (Gper, formerly known as GPR30) is found to be a trophic and protective factor in mediating action of estrogen in adult brain, while its role in developing brain remains to be elucidated. Here we present the expression pattern of Gper and its functions during embryogenesis in zebrafish. Both the mRNA and protein of Gper were detected throughout embryogenesis. Whole mount in situ hybridization (WISH) revealed a wide distribution of gper mRNAs in various regions of the developing brain. Gper knockdown by specific morpholinos resulted in growth retardation in embryos and morphological defects in the developing brain. In addition, induced apoptosis, decreased proliferation of the brain cells and maldevelopment of sensory and motor neurons were also found in the morphants. Our results provide novel insights into Gper functions in the developing brain, revealing that Gper can maintain the survival of the brain cells, and formation and/or differentiation of the sensory and motor neurons.
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GPER mediates the inhibitory actions of estrogen on adipogenesis in 3T3-L1 cells through perturbation of mitotic clonal expansion.
Gen. Comp. Endocrinol.
PUBLISHED: 03-14-2013
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G-protein-coupled estrogen receptor 1 (GPER) mediates non-genomic signaling of estrogenic events. Here we showed for the first time that Gper/GPER is expressed in Swiss 3T3 mouse embryo preadipocytes 3T3-L1, and that Gper/GPER is up-regulated during differentiation of the cells induced by monocyte differentiation-inducing (MDI) cocktail. Activation of GPER by the natural ligand 17?-estradiol (E2), and the specific agonist G1, was shown to inhibit lipid accumulation in 3T3-L1 cells, while such inhibition was reversed upon knockdown of GPER using specific siRNA. GPER was also found to mediate perturbation of mitotic clonal expansion (MCE) in these cells by inhibiting cell cycle arrest during MDI cocktail-induced differentiation. Persistent activation of cell cycle regulating factors cyclin-dependant kinase (CDK) 4, CDK6 and cyclin D1, and phosphorylation of retinoblastoma (Rb) protein at serine 795 was observed in the G1-treated cells. Taken together, our results indicate that E2-GPER signaling leads to an inhibition of adipogenesis in 3T3-L1 cells via perturbation of MCE.
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Canonical and non-canonical barriers facing antimiR cancer therapeutics.
Curr. Med. Chem.
PUBLISHED: 03-01-2013
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Once considered genetic "oddities", microRNAs (miRNAs) are now recognized as key epigenetic regulators of numerous biological processes, including some with a causal link to the pathogenesis, maintenance, and treatment of cancer. The crux of small RNA-based therapeutics lies in the antagonism of potent cellular targets; the main shortcoming of the field in general, lies in ineffective delivery. Inhibition of oncogenic miRNAs is a relatively nascent therapeutic concept, but as with predecessor RNA-based therapies, success hinges on delivery efficacy. This review will describes the canonical (e.g. pharmacokinetics and clearance, cellular uptake, endosome escape, etc.) and non-canonical (e.g. spatial localization and accessibility of miRNA, technical limitations of miRNA inhibition, off-target impacts, etc.) challenges to the delivery of antisense-based anti-miRNA therapeutics (i.e. antimiRs) for the treatment of cancer. Emphasis will be placed on how the current leading antimiR platforms-ranging from naked chemically modified oligonucleotides to nanoscale delivery vehicles-are affected by and overcome these barriers. The perplexity of antimiR delivery presents both engineering and biological hurdles that must be overcome in order to capitalize on the extensive pharmacological benefits of antagonizing tumor-associated miRNAs.
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1,4-dihydroxy-2-naphthoic Acid Induces Apoptosis in Human Keratinocyte: Potential Application for Psoriasis Treatment.
Evid Based Complement Alternat Med
PUBLISHED: 02-25-2013
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Psoriasis, which affects approximately 1-3% of the population worldwide, is a chronic inflammatory skin disorder characterized by epidermal keratinocytes hyperproliferation, abnormal differentiation, and inflammatory infiltration. Decrease in keratinocyte apoptosis is a specific pathogenic phenomenon in psoriasis. Chinese herbs have been used for the treatment of psoriasis in China showing promising effect in clinical trials. A traditional Chinese medicine has relatively fewer side effects with longer remission time and lower recurrence rate. The extract of Rubia cordifolia L. (EA) was previously found by us to induce HaCaT keratinocytes apoptosis. In this study we identified one of the components in Rubia cordifolia L., the anthraquinone precursor 1,4-dihydroxy-2-naphthoic acid (DHNA), induces HaCaT keratinocytes apoptosis through G0/G1 cell cycle arrest. We have also demonstrated that DHNA acts through both caspase-dependent and caspase-independent pathways. Besides, cytotoxicity and IL-1 ? release assays indicate that DHNA causes less irritation problems than dithranol, which is commonly employed to treat psoriasis in many countries. Since DHNA possesses similar apoptotic effects on keratinocytes as dithranol but causes less irritation, DHNA therefore constitutes a promising alternative agent for treating psoriasis. Our studies also provide an insight on the potential of using EA and DHNA, alternatively, as a safe and effective treatment modality for psoriasis.
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Ultrasound, pH, and magnetically responsive crown-ether-coated core/shell nanoparticles as drug encapsulation and release systems.
ACS Appl Mater Interfaces
PUBLISHED: 02-25-2013
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Core@shell nanoparticles with superparamagnetic iron oxide core, mesoporous silica shell, and crown ether periphery were fabricated toward drug delivery and tumor cell imaging. By the concept of nanovalve based on supramolecular gatekeeper, stimuli-responsive drug delivery nanosystems Fe3O4@SiO2@meso-SiO2@crown ethers were synthesized by (i) modified solvothermal reaction; (ii) sol-gel reaction; and (iii) amide coupling reaction. The successful coupling of the dibenzo-crown ethers onto the mesoporous silica shell was confirmed by thermogravimetric analysis and Infrared spectroscopy. In this system, the "ON/OFF" switching of the gatekeeper supramolecules can be controlled by pH-sensitive intramolecular hydrogen bonding or electrostatic interaction (such as metal chelating). Biological evaluation of the nanoparticles renders them noncytotoxic and can be uptaken by L929 cells. In this work, the antitumor drug (doxorubicin) loading and release profiles which were studied by the UV/visible absorption spectroscopy. The mechanism involves the best-fit binding of crown ethers with cesium or sodium ions at different pH values with ultrasonic wave in phosphate buffered saline (PBS). Magnetic resonance imaging analysis of the particles reveals a high relaxivity, rendering them potentially useful theranostic agents.
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Respiratory-induced 3D deformations of the renal arteries quantified with geometric modeling during inspiration and expiration breath-holds of magnetic resonance angiography.
J Magn Reson Imaging
PUBLISHED: 02-06-2013
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To quantify renal artery deformation due to respiration using magnetic resonance (MR) image-based geometric analysis.
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A novel neuropeptide in suppressing luteinizing hormone release in goldfish, Carassius auratus.
Mol. Cell. Endocrinol.
PUBLISHED: 02-05-2013
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The fish reproductive axis is regulated by many neuroendocrine factors. However, factors involved in the suppression of this axis are largely uncharacterized. In this study, we describe a novel neuropeptide derived from the spexin precursor acting as a negative factor to suppress the reproductive axis in teleost. The cDNA sequences of the spexin precursors have been cloned from both zebrafish and goldfish. A 14-aa mature peptide with the C-terminal amidated (spexin-14a: NWTPQAMLYLKGTQ-NH2) is conceivably generated by processing of the spexin precursors in both species. Spexin is mainly expressed in the brain and ovary of zebrafish and spexin-14a-ir cells are located in several brain regions of goldfish. Functionally, goldfish spexin-14a could significantly suppress luteinizing hormone (LH) release in cultured goldfish pituitary cells. Moreover, intraperitoneal injection of spexin-14a could effectively suppress serum LH level. The mRNA expression of spexin is lower in the breeding season and hypothalamic expression of spexin is regulated by gonadal hormones. These results constitute the first report on the novel role of spexin in the negative regulation of the reproductive axis in teleost.
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Identification and characterization of a motilin-like peptide and its receptor in teleost.
Gen. Comp. Endocrinol.
PUBLISHED: 02-05-2013
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Although putative motilin receptor sequences have been reported in teleost, there is no proof for the existence of the motilin gene in teleost. In this study, we have identified a motilin-like gene in the genome of several fish species and cloned its cDNA sequence from zebrafish. The zebrafish motilin-like precursor shares very low amino acid (aa) identities with the previously reported motilin precursors. Processing of the zebrafish motilin-like precursor may generate a 17-aa C-terminal amidated mature peptide, the motilin-like peptide (motilin-LP). A putative zebrafish motilin receptor (MLNR) was also identified in zebrafish. In cultured eukaryotic cells transfected with the zebrafish MLNR, zebrafish motilin-LP could enhance both CRE-driven and SRE-driven promoter activities. Tissue distribution studies indicated that the zebrafish motilin-like gene is mainly expressed in the intestine and liver while the zebrafish MLNR gene is highly expressed in brain regions, suggesting that motilin-LP behaves like other gut hormones to regulate brain functions. These data suggest that the presence of a unique motilin/MNLR system in teleost.
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Regulation of the two kiss promoters in goldfish (Carassius auratus) by estrogen via different ER? pathways.
Mol. Cell. Endocrinol.
PUBLISHED: 01-06-2013
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Kisspeptin stimulates the synthesis and release of gonadotropin via controlling the secretion of gonadotropin releasing hormone in vertebrates. It also mediates the positive or negative feedback regulation of sex steroids on the hypothalamus-gonadotropic axis. In contrast to mammals, two paralogous genes of kisspeptin (kiss1 and kiss2) have been identified in several teleosts, implying the multiplicity of their physiological functions. In the present study, we cloned the promoters of kiss1 and kiss2 genes in goldfish (Carassius auratus), and identified the presence of putative binding sites for estrogen receptors, glucocorticoid receptors, Sp1, AP1, C/EBP and Oct-1. We further demonstrated that the goldfish Kiss neurons co-express the estrogen receptors, with era1 and erb1 in the habenula Kiss1 neurons and era1, era2 and erb1 in the preoptic and hypothalamic Kiss2 neurons. Using transient transfection in HEK293T cells of the two goldfish kiss gene promoters cloned upstream of a luciferase reporter, estrogen (E2, 17?-estradiol) treatment was shown to enhance the promoter activities of the two goldfish kiss genes in the presence of ER?. Deletion analysis of kiss1 promoter indicated that the E2-induced promoter activity was located between position -633 and -317 where no half ERE motifs were found. Point mutation studies on the kiss2 promoter indicated that the E2-stimulated promoter activity was mediated by a half ERE site located at position -57. Results of the present study provide evidence that E2 is capable of exerting positive feedback regulation on the expression of kiss1 and kiss2 in goldfish via ERE-independent or ERE-dependent ER? pathway, respectively.
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Inheritable and precise large genomic deletions of non-coding RNA genes in zebrafish using TALENs.
PLoS ONE
PUBLISHED: 01-01-2013
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Transcription activator-like effector nucleases (TALENs) have so far been applied to disrupt protein-coding genes which constitute only 2-3% of the genome in animals. The majority (70-90%) of the animal genome is actually transcribed as non-coding RNAs (ncRNAs), yet the lack of efficient tools to knockout ncRNA genes hinders studies on their in vivo functions. Here we have developed novel strategies using TALENs to achieve precise and inheritable large genomic deletions and knockout of ncRNA genes in zebrafish. We have demonstrated that individual miRNA genes could be disrupted using one pair of TALENs, whereas large microRNA (miRNA) gene clusters and long non-coding RNA (lncRNA) genes could be precisely deleted using two pairs of TALENs. We have generated large genomic deletions of two miRNA clusters (the 1.2 kb miR-17-92 cluster and the 79.8 kb miR-430 cluster) and one long non-coding RNA (lncRNA) gene (the 9.0 kb malat1), and the deletions are transmitted through the germline. Taken together, our results establish TALENs as a robust tool to engineer large genomic deletions and knockout of ncRNA genes, thus opening up new avenues in the application of TALENs to study the genome in vivo.
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Stat3 inhibition attenuates mechanical allodynia through transcriptional regulation of chemokine expression in spinal astrocytes.
PLoS ONE
PUBLISHED: 01-01-2013
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Signal transducer and activator of transcription 3 (Stat3) is known to induce cell proliferation and inflammation by regulating gene transcription. Recent studies showed that Stat3 modulates nociceptive transmission by reducing spinal astrocyte proliferation. However, it is unclear whether Stat3 also contributes to the modulation of nociceptive transmission by regulating inflammatory response in spinal astrocytes. This study aimed at investigating the role of Stat3 on neuroinflammation during development of pain in rats after intrathecal injection of lipopolysaccharide (LPS).
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Robotic prostate biopsy and its relevance to focal therapy of prostate cancer.
Nat Rev Urol
PUBLISHED: 09-20-2011
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Focal therapy is an individualized treatment option for prostate cancer, which destroys localized cancerous tissue but not normal tissue, thus avoiding the morbidities associated with whole-gland therapy. Accurate cancer localization and precise ablation are integral to the success of focal therapy, which remains unproven owing to suboptimal patient selection. Currently, there are no clinical or biopsy features that can identify unifocal prostate cancer and no imaging modality that can accurately diagnose or localize prostate cancer. MRI diagnosis has the best accuracy but high cost and limited access hinder its widespread adoption. New management options, including focal therapy and active surveillance, require prostate biopsy to detect, localize and characterize the cancer. Transrectal prostate biopsy has a high false-negative detection rate, which might be related to an inability to biopsy the anterior and apical part of the prostate or interoperator variation. Transrectal biopsy is also associated with sepsis and bleeding. Robotic transperineal prostate biopsy can overcome the limitations of transrectal procedures. Robotic biopsy is automated with high accuracy, has improved access to the apex and anterior part of the prostate and has low risk of sepsis. Furthermore, it involves only two skin punctures, compared with template-based transperineal prostate biopsy, which can result in multiple wounds. Robotic prostate biopsy fulfills the fundamental needs of focal therapy and might be the platform for future treatment delivery for prostate cancer.
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Identification of a natural compound by cell-based screening that enhances interferon regulatory factor-1 activity and causes tumor suppression.
Mol. Cancer Ther.
PUBLISHED: 08-04-2011
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The transcription factor interferon regulatory factor-1 (IRF-1) is induced by many tumor-suppressive stimuli and can mediate antiproliferative and proapoptotic effects in cancer cells. Thus, identifying agents that enhance IRF-1 activity may be an effective approach to cancer therapy. A cell-based screening assay was developed to identify extracts and compounds that could enhance IRF-1 activity, using an IRF-1-dependent luciferase reporter cell line. Through this approach, we identified a natural product extract and a known active component of this extract, baicalein, which causes a marked increase in IRF-1-dependent reporter gene expression and IRF-1 protein, with modulation of known IRF-1 targets PUMA and cyclin D1. Baicalein causes suppression of growth in vitro in multiple cancer cell lines in the low micromolar range. IRF-1 plays a role in this growth suppression as shown by significant resistance to growth suppression in a breast cancer cell line stably transfected with short hairpin RNA against IRF-1. Finally, intraperitoneal administration of baicalein by repeated injection causes inhibition of growth in both xenogeneic and syngeneic mouse models of cancer without toxicity to the animals. These findings indicate that identifying enhancers of IRF-1 activity may have utility in anticancer therapies and that cell-based screening for activation of transcription factors can be a useful approach for drug discovery.
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The truncated ghrelin receptor polypeptide (GHS-R1b) is localized in the endoplasmic reticulum where it forms heterodimers with ghrelin receptors (GHS-R1a) to attenuate their cell surface expression.
Mol. Cell. Endocrinol.
PUBLISHED: 07-22-2011
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The ghrelin receptor (GHS-R1a) is remarkable amongst G-protein-coupled receptors for its high degree of constitutive activity, and this agonist-independent activity may be important for its physiological function in the control of food intake and body weight. Ghrelin receptors form heterodimers with the truncated ghrelin receptor polypeptide (GHS-R1b), which has a dominant-negative effect on ghrelin receptor function. Here we show that GHS-R1b has an intracellular localization distinct from ghrelin receptors, being primarily localized in the endoplasmic reticulum. Immunocytochemical studies suggest that GHS-R1b decreases the plasma membrane expression of ghrelin receptors, but the overall distribution profile of ghrelin receptors in isolated subcellular fractions is unaffected by GHS-R1b. Using bioluminescence resonance energy transfer methods, we have shown that while ghrelin receptor homodimers are evenly distributed in all subcellular fractions, GHS-R1a/GHS-R1b heterodimers are concentrated within the endoplasmic reticulum and these results suggest that GHS-R1b traps ghrelin receptors within the endoplasmic reticulum by the process of oligomerization. Furthermore, ghrelin receptors constitutively activated extracellular signal-regulated kinases 1/2 in the endoplasmic reticulum, but this small response was not affected by GHS-R1b and its physiological relevance is uncertain. Taken together, these results suggest that ghrelin receptors can be retained in the endoplasmic reticulum by heterodimerization with GHS-R1b, and constitutive activation of phospholipase C is attenuated due to decreased cell surface expression of ghrelin receptors. However, sufficient ghrelin receptor homodimers can still be expressed on the cell surface for maximal responses to agonist stimulation.
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Sodium coupled bicarbonate influx regulates intracellular and apical pH in cultured rat caput epididymal epithelium.
PLoS ONE
PUBLISHED: 06-23-2011
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The epithelium lining the epididymis provides an optimal acidic fluid microenvironment in the epididymal tract that enable spermatozoa to complete the maturation process. The present study aims to investigate the functional role of Na(+)/HCO(3)(-) cotransporter in the pH regulation in rat epididymis.
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Androgen rather than estrogen up-regulates brain-type cytochrome P450 aromatase (cyp19a1b) gene via tissue-specific promoters in the hermaphrodite teleost ricefield eel Monopterus albus.
Mol. Cell. Endocrinol.
PUBLISHED: 06-14-2011
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CYP19A1 in the brain and pituitary of vertebrates is important for reproductive and non-reproductive processes. In teleosts, it is broadly accepted that estradiol (E(2)) up-regulates cyp19a1b gene via a positive autoregulatory loop. Our present study, however, showed that E(2) did not up-regulate ricefield eel cyp19a1b in the hypothalamus and pituitary, whereas dihydrotestosterone (DHT) or testosterone (T) stimulated cyp19a1b expression only in the pituitary. Two tissue-specific promoters, namely promoter I and II directing the expression in the brain and pituitary respectively, were identified. Promoter I contained a non-consensus estrogen response element (ERE), and consequently did not respond to E(2). Promoter II contained an androgen response element (ARE) and consequently responded to DHT. Taken together, these results demonstrated a novel steroidal regulation of cyp19a1b gene expression and an alternative usage of tissue-specific cyp19a1b promoters in the brain and pituitary of a teleost species, the ricefield eel.
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Prognostic factors and predictive models in renal cell carcinoma: a contemporary review.
Eur. Urol.
PUBLISHED: 06-09-2011
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The natural history of renal cell carcinoma (RCC) is highly unpredictable. Small renal masses may be accompanied by metastatic disease. Conversely, patients with locally advanced disease may enjoy long-term disease-free survival.
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Discovery of a new reproductive hormone in teleosts: pituitary adenylate cyclase-activating polypeptide-related peptide (PRP).
Gen. Comp. Endocrinol.
PUBLISHED: 05-30-2011
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Pituitary adenylate cyclase-activating polypeptide (PACAP)-related peptide (PRP) is a peptide encoded with PACAP in the same precursor protein. Non-mammalian PRPs were previously termed growth hormone-releasing hormone (GHRH)-like peptide, and was regarded as the mammalian GHRH homologue in non-mammalian vertebrates until the discovery of authentic GHRH genes in teleosts and amphibians. Although a highly specific receptor for PRP, which is lost in mammals, is present in non-mammals, a clear function of PRP in vertebrates remains unknown. Using goldfish as a model, here we show the expression of PRP and its cognate receptor in the brain-pituitary-gonadal (BPG) axis, thus suggesting a function of goldfish (gf) PRP in regulating reproduction. We found that gfPRP controls the expression of reproductive hormones in the brain, pituitary and ovary. Goldfish PRP exerts stimulatory effects on the expression of salmon gonadotropin-releasing hormone (sGnRH) in the brain, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in pituitary primary culture cells, but inhibits the expression of LH in the ovary. Using the same technique, we showed that gfPRP did not alter the mRNA level of growth hormone in the pituitary primary culture. In summary, we have discovered the first function of vertebrate PRP in regulating reproduction, which provides a new research direction in studying the neuroendocrine control of reproduction not only in teleosts, but also in other non-mammalian vertebrates.
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Biodegradable poly(amine-co-ester) terpolymers for targeted gene delivery.
Nat Mater
PUBLISHED: 05-19-2011
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Many synthetic polycationic vectors for non-viral gene delivery show high efficiency in vitro, but their usually excessive charge density makes them toxic for in vivo applications. Here we describe the synthesis of a series of high molecular weight terpolymers with low charge density, and show that they exhibit efficient gene delivery, some surpassing the efficiency of the commercial transfection reagents Polyethylenimine and Lipofectamine 2000. The terpolymers were synthesized via enzyme-catalyzed copolymerization of lactone with dialkyl diester and amino diol, and their hydrophobicity adjusted by varying the lactone content and by selecting a lactone comonomer of specific ring size. Targeted delivery of the pro-apoptotic TRAIL gene to tumour xenografts by one of the terpolymers results in significant inhibition of tumour growth, with minimal toxicity both in vitro and in vivo. Our findings suggest that the gene delivery ability of the terpolymers stems from their high molecular weight and increased hydrophobicity, which compensates for their low charge density.
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Celastrol-induced apoptosis in human HaCaT keratinocytes involves the inhibition of NF-?B activity.
Eur. J. Pharmacol.
PUBLISHED: 05-01-2011
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Psoriasis is a chronic inflammatory skin disease affecting 1-3% of the worlds population. Traditional Chinese medicines have been extensively used for treating psoriasis with promising clinical results. Celastrol, a triterpenoid isolated from a Chinese herb Celastrus orbiculatus caulis, has been known to have diverse pharmacological effects such as anti-inflammatory, anti-cancer and antioxidant activities. The present study aimed at evaluating the anti-proliferative action of celastrol on cultured HaCaT cells and elucidating the mechanisms of action involved. Celastrol was shown to inhibit HaCaT cells growth with an IC?? value of 1.1 ?M as measured by MTT assay. The ability of celastrol to induce apoptosis was studied by flow cytometric and western blot analyses. Celastrol was found to be capable of inducing apoptosis in HaCaT cells as characterized by phosphatidyl-serine (PS) externalization, depolarization of mitochondrial membrane potential and activation of caspase-3. The apoptosis induced by celastrol could be suppressed by Z-IETD-FMK and Z-LEHD-FMK, the respective caspase-8 and caspase-9 inhibitor. In addition, western blot analysis revealed a significant augmentation in the protein expression of Bax and attenuation in Bcl-2, suggesting that the celastrol-induced apoptosis acts through both death receptor and mitochondrial pathways. Moreover, western blot analysis on the expression of Rel/NF-?B demonstrated that the celastrol-mediated apoptosis on HaCaT cells was associated with the inhibition of the NF-?B pathway. Taken together, the present project has for the first time identified celastrol as a naturally occurring compound with potent apoptogenic action on cultured human keratinocytes, rendering it a promising candidate for further development into an anti-psoriatic agent.
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Recent development in pleiotropic effects of statins on cardiovascular disease through regulation of transforming growth factor-beta superfamily.
Cytokine Growth Factor Rev.
PUBLISHED: 04-20-2011
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3-Hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, also known as statins, are a drug class that reduce the level of cholesterol in the blood. As a result, statins are used to suppress the progression of cardiovascular disease. Evidence points to another component of statins involving the non-lipid effects of the drug class in preventing cardiovascular disease. One specific mediator of this action is the transforming growth factor ? (TGF-?) superfamily. The TGF-? superfamily consists of proteins that include TGF-? and bone morphogenetic proteins (BMPs). These proteins regulate cellular pathways to mediate effects including immunomodulation, cell cycling, and angiogenesis. One pathway that mediates these effects is Ras. Moreover, within this pathway, different functions are possible depending on the activation of the specific receptor subtype. This review discusses the recent development of the non-lipid effects of statins in preventing cardiovascular disease progression by regulating Ras pathway of the TGF-? superfamily, especially RhoA/ROCK pathway.
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Enhanced siRNA delivery into cells by exploiting the synergy between targeting ligands and cell-penetrating peptides.
Biomaterials
PUBLISHED: 04-04-2011
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We have developed a polymer nanoparticle-based siRNA delivery system that exploits a cell surface binding synergism between targeting ligands and cell-penetrating peptides. Nanoparticles were coated with folate and penetratin via a PEGylated phospholipid linker (DSPE-PEG): the combination of both of these ligands represents a strategy for enhancing intracellular delivery of attached polymer nanoparticles. Nanoparticles were characterized for size, morphology, density of surface modification, and ligand association and retention. The surface coverage achieved on DSPE-PEG-coated nanoparticles is as high as (or higher than) obtained with other ligand-modified nano-scale particulate systems (?0.5-5 pmol ligand/cm²). Additionally, these nanoparticles were loaded with a high density of siRNA (?130-140 pmol siRNA/mg nanoparticles), which is slowly released upon incubation in water. Synergies between the activity of surface binding and cell internalizing ligands on these siRNA-loaded nanoparticles impart delivery enhancements that improve their gene silencing efficacy both in culture and in tumor models. Traditionally, targeting ligands function by binding to cell surface receptors, while cell-penetrating peptides function by nonspecifically transporting across cell membranes. Interestingly, we have observed that improved delivery of these dual-functionalized nanoparticles was in part, a result of increased cell surface avidity afforded by both ligands. This siRNA delivery system presents an approach to surface modification of nanovehicles, in which multiple ligands function in parallel to enhance cell binding and uptake.
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The Karakiewicz nomogram is the most useful clinical predictor for survival outcomes in patients with localized renal cell carcinoma.
Cancer
PUBLISHED: 03-21-2011
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Outcomes after surgical removal of localized renal cell carcinoma (RCC) are variable. There have been multiple prognostic nomograms and risk groups developed for estimation of survival outcomes, with different models in use for evaluating patient eligibility in ongoing trials of adjuvant therapy. The authors aimed to establish the most useful prognostic model for patients with localized RCC to guide trial design, biomarker research, and clinical counseling.
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Tyrosine phosphorylation modulates store-operated calcium entry in cultured rat epididymal basal cells.
J. Cell. Physiol.
PUBLISHED: 03-03-2011
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Store-operated calcium entry (SOCE) is essential for many cellular processes. In this study, we investigated modulation of SOCE by tyrosine phosphorylation in rat epididymal basal cells. The intracellular Ca(2+) ([Ca(2+)]i) measurement showed that SOCE occurred in rat epididymal basal cells by pretreating the cells with thapsigargin (Tg), the inhibitor of sarco-endoplasmic reticulum Ca(2+)-ATPase. To identify the role of Ca(2+) channels in this response, we examined the effects of transient receptor potential canonical channel blockers 2-aminoethoxydiphenyl borate (2-APB), 1-[?-[3-(4-methoxyphenyl)pro-poxy]-4-methoxyphenethyl]-1H-imidazole hydrochloride(SKF96365), Gd(3+), and non-selective cation channel blocker Ni(2+) respectively on SOCE and found that these blockers could inhibit the Ca(2+) influx to different extent. Furthermore, we studied the regulation of SOCE by tyrosine kinase pathway. The inhibitor of tyrosine kinase genistein remarkably suppressed the SOCE response, whereas sodium orthovanadate, the inhibitor of tyrosine phosphatase, greatly enhanced it. The results suggest that tyrosine kinase pathway plays a significant role in the initiation of SOCE and positively modulates SOCE in epididymal basal cells.
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Bufalin induces autophagy-mediated cell death in human colon cancer cells through reactive oxygen species generation and JNK activation.
Free Radic. Biol. Med.
PUBLISHED: 02-04-2011
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Colorectal cancer is the second most common cause of cancer death in the world and about half of the patients with colorectal cancer require adjuvant therapy after surgical resection. Therefore, the eradication of cancer cells via chemotherapy constitutes a viable approach to treating patients with colorectal cancer. In this study, the effects of bufalin isolated from a traditional Chinese medicine were evaluated and characterized in HT-29 and Caco-2 human colon cancer cells. Contrary to its well-documented apoptosis-promoting activity in other cancer cells, bufalin did not cause caspase-dependent cell death in colon cancer cells, as indicated by the absence of significant early apoptosis as well as poly(ADP-ribose) polymerase and caspase-3 cleavage. Instead, bufalin activated an autophagy pathway, as characterized by the accumulation of LC3-II and the stimulation of autophagic flux. The induction of autophagy by bufalin was linked to the generation of reactive oxygen species (ROS). ROS activated autophagy via the c-Jun NH(2)-terminal kinase (JNK). JNK activation increased expression of ATG5 and Beclin-1. ROS antioxidants (N-acetylcysteine and vitamin C), the JNK-specific inhibitor SP600125, and JNK2 siRNA attenuated bufalin-induced autophagy. Our findings unveil a novel mechanism of drug action by bufalin in colon cancer cells and open up the possibility of treating colorectal cancer through a ROS-dependent autophagy pathway.
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Hemodynamic changes quantified in abdominal aortic aneurysms with increasing exercise intensity using mr exercise imaging and image-based computational fluid dynamics.
Ann Biomed Eng
PUBLISHED: 02-02-2011
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Abdominal aortic aneurysm (AAA) is a vascular disease resulting in a permanent, localized enlargement of the abdominal aorta. We previously hypothesized that the progression of AAA may be slowed by altering the hemodynamics in the abdominal aorta through exercise [Dalman, R. L., M. M. Tedesco, J. Myers, and C. A. Taylor. Ann. N.Y. Acad. Sci. 1085:92-109, 2006]. To quantify the effect of exercise intensity on hemodynamic conditions in 10 AAA subjects at rest and during mild and moderate intensities of lower-limb exercise (defined as 33 ± 10% and 63 ± 18% increase above resting heart rate, respectively), we used magnetic resonance imaging and computational fluid dynamics techniques. Subject-specific models were constructed from magnetic resonance angiography data and physiologic boundary conditions were derived from measurements made during dynamic exercise. We measured the abdominal aortic blood flow at rest and during exercise, and quantified mean wall shear stress (MWSS), oscillatory shear index (OSI), and particle residence time (PRT). We observed that an increase in the level of activity correlated with an increase of MWSS and a decrease of OSI at three locations in the abdominal aorta, and these changes were most significant below the renal arteries. As the level of activity increased, PRT in the aneurysm was significantly decreased: 50% of particles were cleared out of AAAs within 1.36 ± 0.43, 0.34 ± 0.10, and 0.22 ± 0.06 s at rest, mild exercise, and moderate exercise levels, respectively. Most of the reduction of PRT occurred from rest to the mild exercise level, suggesting that mild exercise may be sufficient to reduce flow stasis in AAAs.
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A study on the functional interaction between the GH/PRL family of polypeptides with their receptors in zebrafish: Evidence against GHR1 being the receptor for somatolactin.
Mol. Cell. Endocrinol.
PUBLISHED: 02-02-2011
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The growth hormone (GH)/prolactin (PRL) family of polypeptide hormones plays important roles in many aspects of vertebrate physiology. In fish, there is an additional member in this family called somatolactin (SL). Specifically, zebrafish contains five ligands (GH, SL?, SL?, PRL1 and PRL2) and four cognate receptors including two GH receptors (GHR1 and GHR2) and two PRL receptors (PRLR1 and PRLR2). There is much controversy regarding whether one of the two GHRs in teleosts is in fact the receptor of SL. A multitude of different assay methods were employed to study the functional interaction among these ligands and their receptors in zebrafish. These include assessment of the binding between the ligands and the extracellular domains of the receptors using His-tag pulldown assays, activation of receptor-evoked promoter activities by treatment of the receptor-transfected cells with the recombinant hormones, and phosphorylation of post-receptor signaling factors by treatment of receptor-transfected cells with the recombinant hormones. The results showed that the zebrafish GH can only interact with the GHRs and the zebrafish PRLs can only interact with the PRLRs. The zebrafish SLs, found to be biologically active in another assay, were found to be ineffective in interacting with the zebrafish GHRs and PRLRs. Our data argue against the hypothesis that GHR1 is the SL receptor.
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Synthesis of biocompatible, mesoporous Fe(3)O(4) nano/microspheres with large surface area for magnetic resonance imaging and therapeutic applications.
ACS Appl Mater Interfaces
PUBLISHED: 01-13-2011
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This article reports the fabrication of mesoporous Fe(3)O(4) nano/microspheres with a high surface area value (163 m(2)/g, Brunauer-Emmett-Teller) and demonstrates their use for drug loading, release, and magnetic resonance imaging (MRI). These monodispersed, mesoporous Fe(3)O(4) nano/microspheres with controllable average sizes ranging from 50 to 200 nm were synthesized using a Fe(3)O(4)/poly(acrylic acid) hybrid sphere template and subsequent silica shell formation and removal. We found that the SiO(2) coating is a crucial step for the successful synthesis of uniform mesoporous Fe(3)O(4) nano/microspheres. The as-synthesized mesoporous Fe(3)O(4) nanospheres show a high magnetic saturation value (M(s) = 48.6 emu/g) and could be used as MRI contrast agents (r(2) = 36.3 s(-1) mM(-1)). Trypan blue exclusion and MTT assay (see Supporting Information ) cytotoxicity analyses of the nanospheres based on HepG2 and MDCK cells showed that the products were biocompatible, with a lower toxicity than lipofectamine (positive control). Hydrophilic ibuprofen and hydrophobic zinc(II) phthalocyanine drug loading into mesoporous Fe(3)O(4) nanospheres and selected release experiments were successfully achieved. The potential use of mesoporous Fe(3)O(4) nanospheres in biomedical applications, in light of the nano/microspheres efficient drug loading and release, MRI, and low cytotoxicity, has been demonstrated. It is envisaged that mesoporous Fe(3)O(4) nanospheres can be used as drug carriers and MRI contrast agents for the reticuloendothelial system; they can also be delivered locally, such as via a selective catheter.
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Evaluation of data completeness of the prostate cancer registry after robotic radical prostatectomy.
Ann. Acad. Med. Singap.
PUBLISHED: 12-18-2010
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This study evaluated the data completeness in the registration of prostate cancer after robotic radical prostatectomy (RRP) in the Urological Cancer Registry at the Singapore General Hospital (SGH), and its compliance to the international standards of US Commission on Cancer (CoC).
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Insulin-like growth factor 3 is involved in oocyte maturation in zebrafish.
Biol. Reprod.
PUBLISHED: 11-17-2010
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The gonad-specific expression of a recently discovered Igf subtype (Igf3) in teleost has indicated the important role of this novel Igf in the reproductive functions of fish. In the present study using zebrafish as the model organism, we have further examined the gene expression patterns and the physiological role of Igf3 in the ovary. The igf3 gene in zebrafish was found to be alternatively spliced into two transcripts, with transcript variant 1 exclusively expressed in the gonads, and transcript variant 2 only expressed during early development. Using specific antibodies developed for zebrafish Igf3, both the Igf3 prepropeptide and the mature peptide forms of Igf3 were found to be predominantly expressed in the zebrafish ovary. Real-time PCR and in situ hybridization revealed that igf3 mRNA is relatively low in the early follicles, but is significantly increased after the mid-vitellogenic stage (midstage III), and is high in the full-grown follicles. In the full-grown follicles, igf3 mRNA was detected mainly in the somatic follicular cells with a low level of expression in the oocytes. Igf3 immunoreactivity was confined to the follicular cells only. The expression of igf3 was significantly up-regulated in both ovarian fragments and isolated follicles upon treatment with human chorionic gonadotropin in dose- and time-dependent manners. Treatment with 8-bromoadenosine 3,5-cyclic monophosphate or 3-isobutyl-1-methylxanthine also up-regulated the expression of igf3 in full-grown follicles. Incubation of follicles with recombinant zebrafish Igf3 significantly enhanced oocyte maturation in time-, dose-, and stage-dependent manners. The actions of Igf3 could be blocked by cycloheximide, but not by actinomycin D. Taken together, these results support an important role of Igf3 in the ovarian functions of zebrafish, especially in oocyte maturation.
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Prostate Cancer Working Group report.
Jpn. J. Clin. Oncol.
PUBLISHED: 09-28-2010
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The incidence of prostate cancer, while still lower than in Western nations, is increasing rapidly in Asian countries due to a more westernized lifestyle. Prostate cancer mortality is declining in the USA, where most prostate cancers are diagnosed in the early stage. In contrast, the mortality rates of prostate cancer in Asian countries are expected to continue to increase, because the percentage of advanced-stage prostate cancers remains high. Therefore, early detection by prostate-specific antigen screening and a comprehensive strategy for cancer prevention are essential for Asian people. The exposure rate of prostate-specific antigen screening is very low in Asian countries. Increased prostate-specific antigen screening may reduce the mortality rate. The stances regarding population screening differ among countries. Urological associations should promote population screening. Reliable data from Asian countries are needed. The prostate cancer incidence is low in Asian countries, perhaps due to high soy consumption. Isoflavones may prevent prostate cancer in Asian countries, but that is not yet clear. A large, multinational study in Asia is needed to clarify whether or not isoflavone consumption shows efficacy in preventing prostate cancer. Clinical data suggest that hormonal therapy is more effective in Asians than in Westerners. Clinical guidelines should consider including hormonal therapy as one of the options for the treatment of localized prostate cancer. At the same time, effort should be made to decrease the adverse effects of each treatment. Collaborative studies on the treatment of prostate cancer should be carried out among Asian countries.
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Outcome of laparoscopic live donor nephrectomy and impact of double renal arteries: results from two transplant centres.
Asian J Surg
PUBLISHED: 08-04-2010
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Live donor kidney transplantation is consistently superior to deceased donor kidney transplantation. Laparoscopic donor nephrectomy (LDN) is increasingly accepted as a safe and preferred surgical option. To evaluate the outcome of LDN and the impact of multiple arteries, a retrospective review was conducted on patients in two transplant centres.
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Program effectiveness of a Restorative Whole-school Approach for tackling school bullying in Hong Kong.
Int J Offender Ther Comp Criminol
PUBLISHED: 07-16-2010
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With bullying in schools high on policy makers agendas, researchers are looking for effective strategies to tackle its disruptive effects. The present study sets out to address this issue. First, the prevalence of bullying is examined in Hong Kong High Schools, and second, the effectiveness of a Restorative Whole-school Approach (RWsA) in reducing bullying is examined in a quasi-experimental design. The RWsA emphasizes the setting up of restorative goals, clear instructions, team building, and good relationships among students, parents, and teachers. Over the course of 2 years, and across four schools, the effectiveness of this program was observed by comparing an intervention group with a partial intervention group (which did not receive the full treatment) and a control group (which received no treatment whatsoever). The group that received the RWsA treatment exhibited a significant reduction of bullying, higher empathic attitudes, and higher self-esteem in comparison to the partial intervention and the control group.
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Quantification of particle residence time in abdominal aortic aneurysms using magnetic resonance imaging and computational fluid dynamics.
Ann Biomed Eng
PUBLISHED: 05-25-2010
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Hemodynamic conditions are hypothesized to affect the initiation, growth, and rupture of abdominal aortic aneurysms (AAAs), a vascular disease characterized by progressive wall degradation and enlargement of the abdominal aorta. This study aims to use magnetic resonance imaging (MRI) and computational fluid dynamics (CFD) to quantify flow stagnation and recirculation in eight AAAs by computing particle residence time (PRT). Specifically, we used gadolinium-enhanced MR angiography to obtain images of the vessel lumens, which were used to generate subject-specific models. We also used phase-contrast MRI to measure blood flow at supraceliac and infrarenal locations to prescribe physiologic boundary conditions. CFD was used to simulate pulsatile flow, and PRT, particle residence index, and particle half-life of PRT in the aneurysms were computed. We observed significant regional differences of PRT in the aneurysms with localized patterns that differed depending on aneurysm geometry and infrarenal flow. A bulbous aneurysm with the lowest mean infrarenal flow demonstrated the slowest particle clearance. In addition, improvements in particle clearance were observed with increase of mean infrarenal flow. We postulate that augmentation of mean infrarenal flow during exercise may reduce chronic flow stasis that may influence mural thrombus burden, degradation of the vessel wall, and aneurysm growth.
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JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.