JoVE Visualize What is visualize?
Stop Reading. Start Watching.
Advanced Search
Stop Reading. Start Watching.
Regular Search
Find video protocols related to scientific articles indexed in Pubmed.
FGFR1 mediates recombinant thrombomodulin domain-induced angiogenesis.
Cardiovasc. Res.
PUBLISHED: 11-10-2014
Show Abstract
Hide Abstract
The recombinant epidermal growth factor-like domain plus the serine/threonine-rich domain of thrombomodulin (rTMD23) promotes angiogenesis and accelerates the generation of activated protein C (APC), which facilitates angiogenesis. The aim of this study was to elucidate the molecular mechanisms underlying the angiogenic activity of rTMD23.
Related JoVE Video
Anxiety and depressive disorders among patients with esophageal cancer in Taiwan: a nationwide population-based study.
Support Care Cancer
PUBLISHED: 09-02-2014
Show Abstract
Hide Abstract
The comorbidity of depression with anxiety disorders is associated with poorer treatment outcomes, worse quality of life, poorer adherence to treatment, and greater suicide risk in cancer patients.
Related JoVE Video
Photocatalytic degradation of Rhodamine B by microwave-assisted hydrothermal synthesized N-doped titanate nanotubes.
J Environ Sci (China)
PUBLISHED: 06-10-2014
Show Abstract
Hide Abstract
Microwave-induced nitrogen-doped titanate nanotubes (NTNTs) were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), Zeta potential analysis, specific surface area (SBET), and UV-Visible spectroscopy. TEM results indicate that NTNTs retain a tubular structure with a crystalline multiwall and have a length of several hundred nanometers after nitrogen doping. XRD findings demonstrate that the crystalline structure of NTNTs was dominated by anatase, which is favored for photocatalytic application. The Ti-O-N linkage observed in the XPS N 1s spectrum is mainly responsible for narrowing the band gap and eventually enhancing the visible light photoactivity. FT-IR results demonstrated the existence of H?O?, which could be excited by photo-generated holes to form hydroxyl radicals and degrade environmental pollutants. After sintering at 350°C, the UV-Vis absorbance edges of NTNTs significantly shift to the visible-light region, which indicates N atom doping into the nanotubes. Photocatalytic degradation of Rhodamine B (RhB) via NTNTs show good efficiency, with pseudo first-order kinetic model rate constants of 3.7 × 10?³, 2.4 × 10?³ and 8.0 × 10?? sec?¹ at pH3, 7, and 11, respectively.
Related JoVE Video
Neovascular glaucoma after central retinal vein occlusion in pre-existing glaucoma.
BMC Ophthalmol
PUBLISHED: 05-06-2014
Show Abstract
Hide Abstract
To determine the outcome of central retinal vein occlusion (CRVO) in pre-existing glaucoma and the predisposing factors of developing neovascular glaucoma (NVG).
Related JoVE Video
Risk and impact of tuberculosis in patients with chronic myeloid leukemia: A nationwide population-based study in Taiwan.
Int. J. Cancer
PUBLISHED: 05-06-2014
Show Abstract
Hide Abstract
The relationship between chronic myeloid leukemia (CML) and tuberculosis (TB) has not been determined. We conducted a national survey including 1,082 CML patients identified from the Taiwan National Health Insurance database covering a period between 1998 and 2011; the matched non-exposed cohort included 10,820 subjects without CML that were matched for age, sex and comorbidities. The impact of TB was measured by the overall mortality, and the risk factors were identified by a multivariate Cox proportional hazards model. We found the risk of TB was higher in the CML cohort, with an adjusted hazard ratio (aHR) of 3.76 (p?=?0.001) for both pulmonary (aHR 3.23, p?
Related JoVE Video
Induction of ROS-independent JNK-activation-mediated apoptosis by a novel coumarin-derivative, DMAC, in human colon cancer cells.
Chem. Biol. Interact.
PUBLISHED: 03-17-2014
Show Abstract
Hide Abstract
In this study, we investigated the antitumor activity of a novel coumarin derivative, 5,7-dihydroxy-4-methyl-6-(3-methylbutanoyl)-coumarin (DMAC), on colorectal carcinoma. DMAC treatment resulted in substantial proapoptotic activity against colon cancer HCT116 and LoVo cells. Induction of apoptotic characteristics, including cellular shrinkage, chromatin condensation, and Annexin V detection, was observed following DMAC treatment. Mechanistically, we observed that DMAC elicited induction of proteolytic cascade activation including cleavage of caspase-3 and poly ADP-ribose polymerase (PARP) expression and loss of the antiapoptotic proteins, Mcl-1 and Bcl-XL, accompanied by an increase in expression of the proapoptotic protein, Bak. In addition, suppressing c-Jun N-terminal protein kinase (JNK), but not extracellular-regulated protein kinase (ERK) or p38, substantially diminished DMAC-induced cell death and caspase-3 and PARP cleavage. However, pretreatment with antioxidants, including N-acetyl-l-cysteine (NAC) and diphenylene iodonium (DPI), failed to protect against DMAC-elicited apoptosis. Pretreatment with the JNK inhibitor, SP600125, suppressed DMAC-induced JNK phosphorylation, which was accompanied by a reversal of Bcl-XL expression. Moreover, combining DMAC treatment with the conventional anticancer drugs, 5-FU and CPT-11, considerably enhanced their therapeutic efficacies. Structural-activity relationship analyses further revealed that an alkylation substitution at position 6 of the coumarin ring was critical for inducing apoptosis, and the phenyl group at position 4 might have enhanced its bioactivity. Our data showed that DMAC can be used as part of a promising strategy to enhance therapeutic efficacies, and could be used to develop an approach for structure-based drug design for cancer treatment.
Related JoVE Video
SnRK1A-interacting negative regulators modulate the nutrient starvation signaling sensor SnRK1 in source-sink communication in cereal seedlings under abiotic stress.
Plant Cell
PUBLISHED: 02-25-2014
Show Abstract
Hide Abstract
In plants, source-sink communication plays a pivotal role in crop productivity, yet the underlying regulatory mechanisms are largely unknown. The SnRK1A protein kinase and transcription factor MYBS1 regulate the sugar starvation signaling pathway during seedling growth in cereals. Here, we identified plant-specific SnRK1A-interacting negative regulators (SKINs). SKINs antagonize the function of SnRK1A, and the highly conserved GKSKSF domain is essential for SKINs to function as repressors. Overexpression of SKINs inhibits the expression of MYBS1 and hydrolases essential for mobilization of nutrient reserves in the endosperm, leading to inhibition of seedling growth. The expression of SKINs is highly inducible by drought and moderately by various stresses, which is likely related to the abscisic acid (ABA)-mediated repression of SnRK1A under stress. Overexpression of SKINs enhances ABA sensitivity for inhibition of seedling growth. ABA promotes the interaction between SnRK1A and SKINs and shifts the localization of SKINs from the nucleus to the cytoplasm, where it binds SnRK1A and prevents SnRK1A and MYBS1 from entering the nucleus. Our findings demonstrate that SnRK1A plays a key role regulating source-sink communication during seedling growth. Under abiotic stress, SKINs antagonize the function of SnRK1A, which is likely a key factor restricting seedling vigor.
Related JoVE Video
Palonosetron versus first-generation 5-hydroxytryptamine type 3 receptor antagonists for emesis prophylaxis in patients undergoing allogeneic hematopoietic stem cell transplantation.
Ann. Hematol.
PUBLISHED: 02-15-2014
Show Abstract
Hide Abstract
First-generation 5-hydroxytryptamine type 3 (5-HT3) receptor antagonists (RAs) are currently the standard of care for prophylaxis against allo-HSCT-induced emesis. However, the efficacy of this combination in allo-HSCT recipients is not entirely satisfying. We sought to compare the efficacy of first-generation 5-HT3 RAs with that of second-generation 5-HT3 RAs in emesis prevention in allo-HSCT recipients. A total of 51 consecutive patients undergoing allo-HSCT for various hematological diseases in our institution were retrospectively reviewed. Patients who received daily first-generation 5-HT3 RAs, and 60-h palonosetron for emesis prophylaxis were stratified into the standard (n?=?23) and palonosetron (n?=?28) groups, respectively. Emesis severity and rescue therapy requirements in patients between these two groups were compared. Our results showed patients in standard and palonosetron groups had comparable severity of both acute and delayed emesis. However, 52.2 % of the patients in the standard group required rescue therapy, compared to only 21.4 % of the patients in the palonosetron group (p?=?0.046). Subgroup analysis showed rescue therapy for acute emesis was required by 26.1 % of the patients in the standard group and by only 3.6 % of the patients in the palonosetron group (p?=?0.037). In conclusion, palonosetron and first-generation 5-HT3 RAs were at least equally effective in emesis prophylaxis for allo-HSCT recipients. Patients receiving palonosetron, especially for acute emesis, required rescue therapy less frequently than those receiving first-generation 5-HT3 RAs.
Related JoVE Video
MicroRNA-302b-inhibited E2F3 transcription factor is related to all trans retinoic acid-induced glioma cell apoptosis.
J. Neurochem.
PUBLISHED: 02-11-2014
Show Abstract
Hide Abstract
All-trans retinoic acid (ATRA), a derivative of retinoid, is involved in the onset of differentiation and apoptosis in a wide variety of normal and cancer cells. MicroRNAs (miRNAs) are small non-coding RNAs that control gene expression. Several miRNAs were identified to participate in ATRA-mediated cell differentiation. However, no studies have demonstrated whether miRNA can enhance ATRA cytotoxicity, thereby resulting in cell apoptosis. This study investigated the effects of ATRA-mediated miRNA expression in activating apoptotic pathways in glioblastoma. First, we found that high-dose ATRA treatment significantly reduced cell viability, caspase-dependent apoptosis, endoplasmic reticular (ER) stress activation, and intracellular reactive oxygen species accumulation. From microarray data, miR-302b was analyzed as a putative downstream regulator upon ATRA treatment. Furthermore, we found that ATRA up-regulated miR-302b expression in a dose- and time-dependent manner through retinoic acid receptor ?-mediated pathway. Overexpression and knockdown of miR-302b significantly influenced ATRA-mediated cytotoxicity. E2F3, an important transcriptional regulator of glioma proliferation, was validated to be a direct target gene of miR-302b. The miR-302b-reduced E2F3 levels were also identified to be associated with ATRA-mediated glioma cell death. These results emphasize that an ATRA-mediated miR-302b network may provide novel therapeutic strategies for glioblastoma therapy. We propose that high-dose all-trans retinoic acid (ATRA) treatment, a derivative of retinoid, significantly induces glioblastoma cell apoptosis via caspase-dependent apoptosis, endoplasmic reticular (ER) stress, and intracellular reactive oxygen species (ROS) accumulation. The miR-302b overexpression enhanced by ATRA-mediated retinoic acid receptor (RAR)? pathway was also identified. The E2F3 repression, a novel target gene of miR-302b, was involved in ATRA-induced glioblastoma cell cytotoxicity.
Related JoVE Video
Impact on outcomes by measuring tortuosity with reporting standards for thoracic endovascular aortic repair.
J. Vasc. Surg.
PUBLISHED: 01-30-2014
Show Abstract
Hide Abstract
In this study, we assessed the association between the tortuosity of the thoracic aorta as measured by the reporting standards for thoracic endovascular aortic repair (TEVAR), described by the Society for Vascular Surgery, and midterm outcomes after TEVAR for atherosclerotic aneurysms.
Related JoVE Video
Taiwan cobra phospholipase A2 suppresses ERK-mediated ADAM17 maturation, thus reducing secreted TNF-? production in human leukemia U937 cells.
Toxicon
PUBLISHED: 01-27-2014
Show Abstract
Hide Abstract
The goal of this study was to explore the signaling pathway regulating the processing of proADAM17 into ADAM17 in Taiwan cobra phospholipase A2 (PLA2)-treated human leukemia U937 cells. PLA2 induced reactive oxygen species (ROS)-elicited p38 MAPK activation and ERK inactivation in U937 cells. Catalytically inactive bromophenacylated PLA2 (BPB-PLA2) and PLA2 mutants evoked Ca(2+)-mediated p38 MAPK activation, and the level of phosphorylated ERK remained unchanged. PLA2 treatment reduced mature ADAM17 expression and secreted TNF-? (sTNF-?) production. Co-treatment of SB202190 (p38 MAPK inhibitor) and catalytically inactive PLA2 increased ERK phosphorylation, ADAM17 maturation and sTNF-? production. Nevertheless, mRNA levels of ADAM17 and TNF-? were insignificantly altered after PLA2 and SB202190/BPB-PLA2 treatment. ADAM17 activity assay and knock-down of ADAM17 revealed that ADAM17 was involved in sTNF-? production. Restoration of ERK activation increased the processing of proADAM17 into ADAM17 in PLA2-treated cells, while inactivation of ERK reduced ADAM17 maturation in untreated and SB202190/BPB-PLA2-treated cells. Removal of cell surface heparan sulfate abrogated PLA2 and SB202190/BPB-PLA2 effect on ADAM17 maturation. Taken together, the present data reveal that PLA2 suppresses ERK-mediated ADAM17 maturation, thus reducing sTNF-? production in U937 cells. Moreover, the binding with heparan sulfate is crucial for the PLA2 effect.
Related JoVE Video
Bovine induced pluripotent stem cells are more resistant to apoptosis than testicular cells in response to mono-(2-ethylhexyl) phthalate.
Int J Mol Sci
PUBLISHED: 01-25-2014
Show Abstract
Hide Abstract
Although the androgen receptor (AR) has been implicated in the promotion of apoptosis in testicular cells (TSCs), the molecular pathway underlying AR-mediated apoptosis and its sensitivity to environmental hormones in TSCs and induced pluripotent stem cells (iPSCs) remain unclear. We generated the iPSCs from bovine TSCs via the electroporation of OCT4. The established iPSCs were supplemented with leukemia inhibitory factor and bone morphogenetic protein 4 to maintain and stabilize the expression of stemness genes and their pluripotency. Apoptosis signaling was assessed after exposure to mono-(2-ethylhexyl) phthalate (MEHP), the active metabolite of di-(2-ethylhexyl) phthalate. Here, we report that iPSCs were more resistant to MEHP-induced apoptosis than were original TSCs. MEHP also repressed the expression of AR and inactivated WNT signaling, and then led to the commitment of cells to apoptosis via the cyclin dependent kinase inhibitor p21CIP1. The loss of the frizzed receptor 7 and the gain of p21CIP were responsible for the stimulatory effect of MEHP on AR-mediated apoptosis. Our results suggest that testicular iPSCs can be used to study the signaling pathways involved in the response to environmental disruptors, and to assess the toxicity of environmental endocrine disruptors in terms of the maintenance of stemness and pluripotency.
Related JoVE Video
Green tea (-)-epigallocatechin gallate suppresses IGF-I and IGF-II stimulation of 3T3-L1 adipocyte glucose uptake via the glucose transporter 4, but not glucose transporter 1 pathway.
Gen. Comp. Endocrinol.
PUBLISHED: 01-13-2014
Show Abstract
Hide Abstract
This study investigated the pathways involved in EGCG modulation of insulin-like growth factor (IGF)-stimulated glucose uptake in 3T3-L1 adipocytes. EGCG inhibited IGF-I and IGF-II stimulation of adipocyte glucose uptake with dose and time dependencies. EGCG at 20?M for 2h decreased IGF-I- and IGF-II-stimulated glucose uptake by 59% and 64%, respectively. Pretreatment of adipocytes with antibody against the EGCG receptor (also known as the 67-kDa laminin receptor; 67LR), prevented the effects of EGCG on IGF-increased glucose uptake, but pretreatment with normal rabbit immunoglobulin did not. This suggests that the 67LR mediates the anti-IGF effect of EGCG on adipocyte glucose uptake. Further analysis indicated EGCG, IGF-I, and IGF-II did not alter total levels of GLUT1 or GLUT4 protein. However, EGCG prevented the IGF-increased GLUT4 levels in the plasma membrane and blocked the IGF-decreased GLUT4 levels in low-density microsomes. Neither EGCG nor its combination with IGF altered GLUT1 protein levels in the plasma membrane and low-density microsomes. EGCG also suppressed the IGF-stimulated phosphorylation of IGF signaling molecules, PKC?/?, but not AKT and ERK1/2, proteins. This study suggests that EGCG suppresses IGF stimulation of 3T3-L1 adipocyte glucose uptake through inhibition of the GLUT4 translocation, but not through alterations of the GLUT1 pathway.
Related JoVE Video
Population-based 5-year Follow-up Study in Taiwan of Osteoporosis and Risk of Periodontitis.
J. Periodontol.
PUBLISHED: 09-03-2013
Show Abstract
Hide Abstract
Objective: Osteoporosis and periodontitis are both considered as the global health issues which threaten postmenopausal women and elder population. However, the correlation between osteoporosis and periodontitis is still unclear. Materials and methods: Using a nationwide Taiwanese population-based database, data from osteoporosis patients (year 2003 to 2005; N = 2527) and 7575 individuals who were matched to each patient by their age and gender were analyzed. All participates were tracked for 5 years from the date of enrollment to observe the percentage of patients who developed periodontitis. Cox proportional hazard regressions were performed to evaluate 5-year periodontitis-free survival rates. Results: Among the total sample, 3060 individuals were diagnosed with periodontitis during the 5-year follow-up period: 792 in the study cohort and 2268 in the comparison cohort. The adjusting hazard ratio (HR) for periodontitis in patients with osteoporosis compared to the non-osteoporosis subjects during the 5-year follow-up was 1.14 (95% confidence interval [CI] = 1.05-1.24, p < 0.01). Conclusions: This population-based study indicated that osteoporosis patients may have an increased risk of periodontitis.
Related JoVE Video
Thrombomodulin functions as a plasminogen receptor to modulate angiogenesis.
FASEB J.
PUBLISHED: 08-13-2013
Show Abstract
Hide Abstract
Urokinase-type plasminogen activator (uPA) activates plasminogen (Plg) through a major pericellular proteolytic system involved in cell migration and angiogenesis; however, the Plg receptor that participates in uPA-mediated Plg activation has not yet been identified. In this study, we demonstrated that thrombomodulin (TM), a type I transmembrane glycoprotein, is a novel Plg receptor that plays a role in pericellular proteolysis and cell migration. Plg activation at the cell surface and the extent of its cell migration- and invasion-promoting effect are cellular TM expression dependent. Direct binding of Plg and the recombinant TM extracellular domain, with a KD of 0.1-0.3 ?M, was determined through surface plasmon resonance analysis. Colocalization of TM, Plg, and the uPA receptor within plasma membrane lipid rafts, at the leading edge of migrating endothelial cells, was demonstrated and was also shown to overlap with areas of major pericellular proteolysis. Moreover, the roles of TM and Plg in neoangiogenesis were demonstrated in vivo through the skin wound-healing model. In conclusion, we propose that TM is a novel Plg receptor that regulates uPA/uPA receptor-mediated Plg activation and pericellular proteolysis within lipid rafts at the leading edge of migrating cells during angiogenesis.
Related JoVE Video
A self-assembled microbonded germanium/silicon heterojunction photodiode for 25?Gb/s high-speed optical interconnects.
Sci Rep
PUBLISHED: 07-29-2013
Show Abstract
Hide Abstract
A novel technique using surface tension to locally bond germanium (Ge) on silicon (Si) is presented for fabricating high performance Ge/Si photodiodes. Surface tension is a cohesive force among liquid molecules that tends to bring contiguous objects in contact to maintain a minimum surface energy. We take advantage of this phenomenon to fabricate a heterojunction optoelectronic device where the lattice constants of joined semiconductors are different. A high-speed Ge/Si heterojunction waveguide photodiode is presented by microbonding a beam-shaped Ge, first grown by rapid-melt-growth (RMG) method, on top of a Si waveguide via surface tension. Excellent device performances such as an operating bandwidth of 17?GHz and a responsivity of 0.66 and 0.70?A/W at the reverse bias of -4 and -6?V, respectively, are demonstrated. This technique can be simply implemented via modern complementary metal-oxide-semiconductor (CMOS) fabrication technologies for integrating Ge on Si devices.
Related JoVE Video
The forkhead transcription factor FOXO1 stimulates the expression of the adipocyte resistin gene.
Gen. Comp. Endocrinol.
PUBLISHED: 07-18-2013
Show Abstract
Hide Abstract
Resistin is known as an adipocyte-specific hormone that can cause insulin resistance and decrease adipocyte differentiation. It can be regulated by transcriptional factors, but the possible role of forkhead transcription factor FOXO1 in regulating resistin gene expression is still unknown. Using 3T3 fibroblast and C3H10T1/2 and 3T3-L1 adipocytes, we found that transient overexpression of a non-phosphorylatable, constitutively active FOXO1, but not the wild type of FOXO1 or a DNA binding-deficient FOXO1, activated resistin promoter-directed luciferase expression. However, transient overexpression of a dominant-negative FOXO1 inactivated resistin promoter activity and reduced resistin mRNA expression. These observations indicate that the action of FOXO1 on resistin gene expression requires the activation of FOXO1 and that the effect of FOXO1 depends on the phosphorylation and dephosphorylation of FOXO1. The FOXO1 protein target sites on the resistin promoter were localized to the proximal -3545 to -787bp of 5-flanking region of the resistin promoter. A chromatin immunoprecipitation assay also showed that FOXO1 bound the resistin promoter at nucleotide regions of -1539 to -1366bp and -1016 to -835bp, but not at the regions of -795 to -632bp. Results of this study suggest that FOXO1 transcription factor likely activates the expression of adipocyte resistin gene via direct association with the upstream resistin promoter.
Related JoVE Video
Surgeon elective abdominal aortic aneurysm repair volume and outcomes of ruptured abdominal aortic aneurysm repair: a 12-year nationwide study.
World J Surg
PUBLISHED: 07-18-2013
Show Abstract
Hide Abstract
The purpose of the present study was to examine the effects of surgeon elective abdominal aortic aneurysm repair volume on outcomes after ruptured abdominal aortic aneurysm (rAAA) repair.
Related JoVE Video
The induction of heme oxygenase-1 suppresses heat shock protein 90 and the proliferation of human breast cancer cells through its byproduct carbon monoxide.
Toxicol. Appl. Pharmacol.
PUBLISHED: 07-08-2013
Show Abstract
Hide Abstract
Heme oxygenase (HO)-1 is an oxidative stress-response enzyme which catalyzes the degradation of heme into bilirubin, ferric ion, and carbon monoxide (CO). Induction of HO-1 was reported to have antitumor activity; the inhibitory mechanism, however, is still unclear. In the present study, we found that treatment with [Ru(CO)3Cl2]2 (RuCO), a CO-releasing compound, reduced the growth of human MCF7 and MDA-MB-231 breast cancer cells. Analysis of growth-related proteins showed that treatment with RuCO down-regulated cyclinD1, CDK4, and hTERT protein expressions. Interestingly, RuCO treatment resulted in opposite effects on wild-type and mutant p53 proteins. These results were similar to those of cells treated with geldanamycin (a heat shock protein (HSP)90 inhibitor), suggesting that RuCO might affect HSP90 activity. Moreover, RuCO induced mutant p53 protein destabilization accompanied by promotion of ubiquitination and proteasome degradation. The induction of HO-1 by cobalt protoporphyrin IX (CoPP) showed consistent results, while the addition of tin protoporphyrin IX (SnPP), an HO-1 enzymatic inhibitor, diminished the RuCO-mediated effect. RuCO induction of HO-1 expression was reduced by a p38 mitogen-activated protein kinase inhibitor (SB203580). Additionally, treatment with a chemopreventive compound, curcumin, induced HO-1 expression accompanied with reduction of HSP90 client protein expression. The induction of HO-1 by curcumin inhibited 12-O-tetradecanoyl-13-acetate (TPA)-elicited matrix metalloproteinase-9 expression and tumor invasion. In conclusion, we provide novel evidence underlying HO-1s antitumor mechanism. CO, a byproduct of HO-1, suppresses HSP90 protein activity, and the induction of HO-1 may possess potential as a cancer therapeutic.
Related JoVE Video
Measures of carotid-femoral pulse wave velocity and augmentation index are not reliable in patients with abdominal aortic aneurysm.
J. Hypertens.
PUBLISHED: 06-12-2013
Show Abstract
Hide Abstract
Measures of carotid-femoral pulse wave velocity (cf-PWV) and carotid augmentation index (cAI) may be affected by the presence of an abdominal aortic aneurysm (AAA). We, therefore, investigated series of various measures of arterial stiffness and wave reflections in patients with AAA, before and 4 weeks after endovascular aneurysm repair (EVAR).
Related JoVE Video
Control of Oxidative Stress and Generation of Induced Pluripotent Stem Cell-like Cells by Jun Dimerization Protein 2.
Cancers (Basel)
PUBLISHED: 06-03-2013
Show Abstract
Hide Abstract
We report here that the Jun dimerization protein 2 (JDP2) plays a critical role as a cofactor for the transcription factors nuclear factor-erythroid 2-related factor 2 (Nrf2) and MafK in the regulation of the antioxidants and production of reactive oxygen species (ROS). JDP2 associates with Nrf2 and MafK (Nrf2-MafK) to increase the transcription of antioxidant response element-dependent genes. Oxidative-stress-inducing reagent led to an increase in the intracellular accumulation of ROS and cell proliferation in Jdp2 knock-out mouse embryonic fibroblasts. In Jdp2-Cre mice mated with reporter mice, the expression of JDP2 was restricted to granule cells in the brain cerebellum. The induced pluripotent stem cells (iPSC)-like cells were generated from DAOY medulloblastoma cell by introduction of JDP2, and the defined factor OCT4. iPSC-like cells expressed stem cell-like characteristics including alkaline phosphatase activity and some stem cell markers. However, such iPSC-like cells also proliferated rapidly, became neoplastic, and potentiated cell malignancy at a later stage in SCID mice. This study suggests that medulloblastoma cells can be reprogrammed successfully by JDP2 and OCT4 to become iPSC-like cells. These cells will be helpful for studying the generation of cancer stem cells and ROS homeostasis.
Related JoVE Video
The impact of bird-beak configuration on aortic remodeling of distal arch pathology after thoracic endovascular aortic repair with the Zenith Pro-Form TX2 thoracic endograft.
J. Vasc. Surg.
PUBLISHED: 05-03-2013
Show Abstract
Hide Abstract
Structural changes and incomplete endograft apposition to the aortic arch (bird-beak configuration) after thoracic endovascular aortic repair are poorly understood. The aim of this study was to analyze the morphologic changes, conformability, and angulation factors in patients who underwent stainless steel-based stent graft repair of thoracic aortic pathology.
Related JoVE Video
The role of SIRT1/AKT/ERK pathway in ultraviolet B induced damage on human retinal pigment epithelial cells.
Toxicol In Vitro
PUBLISHED: 05-01-2013
Show Abstract
Hide Abstract
Ultraviolet (UV)-induced damage plays a major role in ocular diseases, such as cataracts and retinal degeneration. UVB may also cause retinal phototoxicity and photic retinopathy. In this study, we explored the effects of UVB on the cell cycle and the role of silent mating type information regulation 2 homolog 1 (SIRT1) in the UVB-induced damage. UVB dose-dependently suppressed the growth of retinal pigment epithelial (RPE) cells by activating the phosphatidylinositol 3-kinase (PI3K) pathway and triggering cell cycle arrest at the S phase. SIRT1, an NAD-dependent histone deacetylase, is involved in multiple biological processes, such as the stress response and the regulation of the cell cycle. However, its role in the effects of UVB on RPE cells is unclear. We showed that UVB down-regulates SIRT1 expression in a dose-dependent manner. Resveratrol, an SIRT1 activator, prevented the UVB-induced damage by inhibiting AKT and ERK phosphorylation. A specific PI3K inhibitor attenuated the UVB-induced ERK1/2 and p53 phosphorylation. Finally, UVB activated the PI3K/AKT/ERK pathway by reducing the expression of SIRT1 in ARPE-19 cells. Our study, therefore, illustrated the molecular mechanisms of UVB-induced phototoxicity and damage of RPE cells. SIRT1 and resveratrol may be significant regulators, protecting against UVB-induced injury.
Related JoVE Video
Image-guided lung tumor ablation: principle, technique, and current status.
J Chin Med Assoc
PUBLISHED: 04-20-2013
Show Abstract
Hide Abstract
Image-guided tumor ablation for lung malignancies has emerged as a treatment modality for medically inoperable patients. Overall, image-guided lung tumor ablation is a minimally invasive procedure that has an acceptable safety profile and less impact on lung function. This is important for patients with poor pulmonary and/or cardiac functions or with multiple comorbidities, which prevent them from undergoing surgery, chemotherapy, and radiation therapy. Herein, we review the principle, techniques, clinical application, and patient outcomes of image-guided lung tumor ablation.
Related JoVE Video
A functional polymorphism at the FGF10 gene is associated with extreme myopia.
Invest. Ophthalmol. Vis. Sci.
PUBLISHED: 04-20-2013
Show Abstract
Hide Abstract
Fibroblast growth factor-10 (FGF10) can modulate extracellular matrix associated genes and, therefore, it could be a myopia susceptibility gene. This study used an animal model, single nucleotide polymorphisms (SNPs) association, and genetic functional assay to evaluate FGF10 gene for myopia.
Related JoVE Video
Human plasminogen kringle 1-5 inhibits angiogenesis and induces thrombomodulin degradation in a protein kinase A-dependent manner.
J. Mol. Cell. Cardiol.
PUBLISHED: 04-03-2013
Show Abstract
Hide Abstract
Kringle 1-5 (K1-5), an endogenous proteolytic fragment of human plasminogen (Plg), is an angiostatin-related protein that inhibits angiogenesis. Many angiostatin-related proteins have been identified, but the detailed molecular mechanisms underlying their antiangiogenic effects remain unclear. Thrombomodulin (TM) is a transmembrane glycoprotein that plays a major role in the anticoagulation process in endothelial cells. Previously, we demonstrated that recombinant TM could interact with Plg to enhance Plg activation. In the present study, we investigated the interaction between TM and K1-5, and their functions in endothelial cells. We found that K1-5 colocalized with TM and directly interacted with TM through the TM lectin-like domain. After K1-5 interacted with TM, it induced TM internalization and degradation. In addition, the K1-5-induced TM internalization and degradation in proteasomes after ubiquitin modification were dependent on protein kinase A (PKA). Moreover, a PKA-specific inhibitor reversed the effects of K1-5 on cell migration and tube formation. Consistent with these findings, TM overexpression resulted in increased cell migration; moreover, K1-5 inhibited the increase of TM-mediated cell migration in a PKA-dependent manner. We determined that TM acts as a K1-5 receptor and that K1-5 induces TM internalization, ubiquitination, and degradation through the PKA pathway, by which K1-5 may inhibit endothelial cell migration and tube formation.
Related JoVE Video
Anterior gradient 2: a novel sensitive tumor marker for metastatic oral cancer.
Cancer Lett.
PUBLISHED: 03-13-2013
Show Abstract
Hide Abstract
The prevention of oral squamous cell carcinoma metastasis to improve overall patient survival has provided the rationale for biomarker development. We used the Transwell invasion assay to isolate a highly metastatic subpopulation, HSC-3-5 cells, with almost the same genetic background as HSC-3 cells but a higher metastatic capacity accompanied by cytoskeletal rearrangements and mesenchymal transformation. HSC-3-5 cells also showed tumorigenic and metastatic characteristics in vivo. In addition, Anterior gradient 2 (agr2), a pro-oncogenic signaling intermediate, was identified from gene expression profiling, and overexpression of AGR2 showed a positive correlation with oral tumor metastasis. Taken together, our data suggest that AGR2 may be a novel sensitive biomarker for metastatic oral cancer.
Related JoVE Video
Evodiamine, a plant alkaloid, induces calcium/JNK-mediated autophagy and calcium/mitochondria-mediated apoptosis in human glioblastoma cells.
Chem. Biol. Interact.
PUBLISHED: 03-13-2013
Show Abstract
Hide Abstract
Glioblastomas, the most common primary gliomas, are characterized by increased invasion and difficult therapy. Major clinical medicines for treating gliomas merely extend the survival time for a number of months. Therefore, development of new agents against gliomas is important. Autophagy, a process for degrading damaged organelles and proteins, is an adaptive response to environmental stress. However, the role of autophagy in glioblastoma development still needs to be further investigated. Evodiamine, a major alkaloid isolated from Evodia rutaecarpa Bentham, has various pharmacological activities, such as inhibiting tumor growth and metastatic properties. However, the effects of evodiamine on glioblastomas and their detailed molecular mechanisms and autophagy formation are not well understood. In this study, we observed that evodiamine induced dose- and time-dependent apoptosis in glioma cells. Blockade of calcium channels in endoplasmic reticulum (ER) significantly reduced evodiamine-induced cytosolic calcium elevation, apoptosis, and mitochondrial depolarization, which suggests that evodiamine induces a calcium-mediated intrinsic apoptosis pathway. Interestingly, autophagy was also enhanced by evodiamine, and had reached a plateau by 24h. Pharmacological inhibition of autophagy resulted in increased apoptosis and reduced cell viability. Inhibition of ER calcium channel activation also significantly reduced evodiamine-induced autophagy. Inactivation of c-Jun N-terminal kinases (JNK) suppressed evodiamine-mediated autophagy accompanied by increased apoptosis. Furthermore, evodiamine-mediated JNK activation was abolished by BAPTA-AM, an intracellular calcium scavenger, suggesting that evodiamine mediates autophagy via a calcium-JNK signaling pathway. Collectively, these results suggest that evodiamine induces intracellular calcium/JNK signaling-mediated autophagy and calcium/mitochondria-mediated apoptosis in glioma cells.
Related JoVE Video
Relative contraindications for percutaneous tracheostomy: from the surgeons perspective.
Surg. Today
PUBLISHED: 01-30-2013
Show Abstract
Hide Abstract
Percutaneous tracheostomy (PT) has gained worldwide acceptance as a bedside procedure by intensivists, but its popularity has declined based on reports of some relative contraindications. The aim of this study was to ascertain the perioperative comorbidities of PT when it is performed by surgeons with experience performing standard tracheostomy.
Related JoVE Video
A functional polymorphism of PON1 interferes with microRNA binding to increase the risk of ischemic stroke and carotid atherosclerosis.
Atherosclerosis
PUBLISHED: 01-19-2013
Show Abstract
Hide Abstract
Single nucleotide polymorphisms (SNPs) located at microRNA (miRNA) binding sites (miR-SNPs) can affect the expression of genes. This study aimed to identify the miR-SNPs associated with atherosclerosis and stroke.
Related JoVE Video
Thrombomodulin regulates keratinocyte differentiation and promotes wound healing.
J. Invest. Dermatol.
PUBLISHED: 01-15-2013
Show Abstract
Hide Abstract
The membrane glycoprotein thrombomodulin (TM) has been implicated in keratinocyte differentiation and wound healing, but its specific function remains undetermined. The epidermis-specific TM knockout mice were generated to investigate the function of TM in these biological processes. Primary cultured keratinocytes obtained from TM(lox/lox); K5-Cre mice, in which TM expression was abrogated, underwent abnormal differentiation in response to calcium induction. Poor epidermal differentiation, as evidenced by downregulation of the terminal differentiation markers loricrin and filaggrin, was observed in TM(lox/lox); K5-Cre mice. Silencing TM expression in human epithelial cells impaired calcium-induced extracellular signal-regulated kinase pathway activation and subsequent keratinocyte differentiation. Compared with wild-type mice, the cell spreading area and wound closure rate were lower in keratinocytes from TM(lox/lox); K5-Cre mice. In addition, the lower density of neovascularization and smaller area of hyperproliferative epithelium contributed to slower wound healing in TM(lox/lox); K5-Cre mice than in wild-type mice. Local administration of recombinant TM (rTM) accelerated healing rates in the TM-null skin. These data suggest that TM has a critical role in skin differentiation and wound healing. Furthermore, rTM may hold therapeutic potential for the treatment of nonhealing chronic wounds.
Related JoVE Video
Cyclosporine a eye drop-induced elongated eyelashes: a case report.
Case Rep Ophthalmol
PUBLISHED: 12-17-2011
Show Abstract
Hide Abstract
The most common ocular adverse event following the use of cyclosporine A (CsA) 0.05% ophthalmic emulsion is ocular burning (17%). Other adverse effects that have been reported include conjunctival hyperemia (1-5%), discharge, epiphora, eye pain, foreign body sensation, pruritus, stinging and blurred vision. Here, we report a specific side effect of CsA, namely eye drop-induced eyelash elongation in a patient with refractory giant papillary conjunctivitis.
Related JoVE Video
Negative feedback regulation between microRNA let-7g and the oxLDL receptor LOX-1.
J. Cell. Sci.
PUBLISHED: 12-01-2011
Show Abstract
Hide Abstract
Lectin-like oxidized LDL receptor-1 (LOX-1) is a surface scavenger receptor for oxidized low-density lipoprotein (oxLDL). Several transcription factors have been reported to regulate LOX-1 expression. MicroRNAs are small noncoding RNAs that control gene expression, but there have been no reports of LOX-1 expression being regulated by microRNAs. Because the microRNA let-7g has been predicted to bind to LOX-1 mRNA, we investigated whether let-7g can regulate LOX-1 expression. Our experiments first demonstrated that oxLDL can reduce let-7g expression. We later confirmed that there is a let-7g binding site on the 3-untranslated region of LOX-1 mRNA. We showed that intracellular Ca(2+)-activated protein kinase C is involved in the oxLDL-LOX-1-let-7g pathway. Bioinformatics predicted that the let-7g promoter has a binding site for the transcriptional repressor OCT-1. We used a promoter assay and chromatin immunoprecipitation to confirm this binding. Consequently, knockdown of OCT-1 was found to increase let-7g expression. Transfection of let-7g inhibited oxLDL-induced LOX-1 and OCT-1 expression, cell proliferation and migration. Mice fed with a high-fat diet showed a decrease in let-7g and an increase in LOX-1 and OCT-1. A study on humans showed the serum levels of let-7g are lower in subjects with hypercholesterolemia compared with normal controls. Our findings identify a negative feedback regulation between let-7g and LOX-1, and indicate that let-7g could be a target to treat cardiovascular disease.
Related JoVE Video
The recombinant lectin-like domain of thrombomodulin inhibits angiogenesis through interaction with Lewis Y antigen.
Blood
PUBLISHED: 11-18-2011
Show Abstract
Hide Abstract
Lewis Y Ag (LeY) is a cell-surface tetrasaccharide that participates in angiogenesis. Recently, we demonstrated that LeY is a specific ligand of the recombinant lectin-like domain of thrombomodulin (TM). However, the biologic function of interaction between LeY and TM in endothelial cells has never been investigated. Therefore, the role of LeY in tube formation and the role of the recombinant lectin-like domain of TM-TM domain 1 (rTMD1)-in antiangiogenesis were investigated. The recombinant TM ectodomain exhibited lower angiogenic activity than did the recombinant TM domains 2 and 3. rTMD1 interacted with soluble LeY and membrane-bound LeY and inhibited soluble LeY-mediated chemotaxis of endothelial cells. LeY was highly expressed on membrane ruffles and protrusions during tube formation on Matrigel. Blockade of LeY with rTMD1 or Ab against LeY inhibited endothelial tube formation in vitro. Epidermal growth factor (EGF) receptor in HUVECs was LeY modified. rTMD1 inhibited EGF receptor signaling, chemotaxis, and tube formation in vitro, and EGF-mediated angiogenesis and tumor angiogenesis in vivo. We concluded that LeY is involved in vascular endothelial tube formation and rTMD1 inhibits angiogenesis via interaction with LeY. Administration of rTMD1 or recombinant adeno-associated virus vector carrying TMD1 could be a promising antiangiogenesis strategy.
Related JoVE Video
Sheehan syndrome in Costa Rica: clinical experience with 60 cases.
Endocr Pract
PUBLISHED: 11-09-2011
Show Abstract
Hide Abstract
To describe the clinical and hormonal characteristics of patients with Sheehan syndrome.
Related JoVE Video
Anaplastic large cell lymphoma with paraneoplastic leukocytosis: a clinicopathological analysis of five cases.
APMIS
PUBLISHED: 09-22-2011
Show Abstract
Hide Abstract
Anaplastic large cell lymphoma (ALCL) is a type of T-cell lymphoma with a relatively favorable prognosis. However, a certain group of ALCLs is highly aggressive, featuring paraneoplastic leukocytosis (PL) in clinical presentation. The present study evaluated five cases of ALCL presenting with PL, including four men and one woman, with a median age of 58 years. All cases revealed leukocytosis with a range from 15.3 to 112.9 × 10(3) /?L. Five (100%) and 4 (80%) cases demonstrated immunoreactivity for granulocyte-colony-stimulating factor (G-CSF) and tumor necrosis factor-alpha (TNF-?), respectively. There were significant differences in the expression of G-CSF and TNF-? between ALCL cases with or without PL (p < 0.05 for both). The prognosis of ALCL patients with PL was poor. Four of five patients (80%) died of the disease within a median survival time of 3.5 weeks. The release of G-CSF and TNF-? from lymphoma cells may associate with ALCL presenting with PL, leading to cytokine crisis and even poorer prognosis.
Related JoVE Video
OxLDL causes both epigenetic modification and signaling regulation on the microRNA-29b gene: novel mechanisms for cardiovascular diseases.
J. Mol. Cell. Cardiol.
PUBLISHED: 09-15-2011
Show Abstract
Hide Abstract
MicroRNA-29b has been reported to epigenetically regulate proatherogenic genes in response to oxLDL. Since transcription factors and epigenetic regulations are important mechanisms to regulate gene expression, we investigated whether these mechanisms are involved in oxLDL-induced microRNA-29b upregulation. First, we confirmed that microRNA-29b expression was increased in the aorta of mice fed with a high-fat diet, which was consistent with our previous in vitro findings. Next, we found that oxLDL only activated the microRNA-29b-1/microRNA-29a cluster gene on chromosome 7 but not the other distinct microRNA-29b gene located on chromosome 1. Using the promoter reporter assay and chromatin immunoprecipitation, activator protein-1 (AP-1) was shown to bind to the microRNA-29b-1 promoter. We further identified the signaling pathway of LOX-1/Ca(2+)/ROS/ERK/c-Fos was involved in oxLDL-mediated microRNA-29b overexpression after treating with the MAPTAM (Ca(2+) chelator), NAC (ROS scavenger), U0126 (ERK inhibitor) and c-Fos (one of the AP-1 proteins) shRNA, respectively. To investigate epigenetic regulations, we found that microRNA-29b promoter contained no CpG islands for DNA methylation. Therefore we investigated whether histone modifications influence microRNA-29b promoter activity. We showed that down-regulation of HDAC1 and the modifications on histone 3 lysine 4 (H3K4) and H3K9 significantly affected microRNA-29b expression. Furthermore, knockdown of c-Fos expression attenuated the effect of oxLDL-induced histone modifications on the microRNA-29b gene expression. Taken together, our data suggest that both transcription factor activation and histone modifications are important regulatory mechanisms of oxLDL-induced atherogenic process. This article is part of a Special Issue entitled OxLDL causes both epigenetic modification and signaling regulation on the microRNA-29b gene: Novel mechanisms for cardiovascular diseases.
Related JoVE Video
Role of a propeller loop in the quaternary structure and enzymatic activity of prolyl dipeptidases DPP-IV and DPP9.
FEBS Lett.
PUBLISHED: 09-03-2011
Show Abstract
Hide Abstract
The dipeptidyl peptidase (DPP) family members, including DPP-IV, DPP8, DPP9 and others, cleave the peptide bond after the penultimate proline residue and are drug target rich. The dimerization of DPP-IV is required for its activity. A propeller loop located at the dimer interface is highly conserved within the family. Here we carried out site-directed mutagenesis on the loop of DPPIV and identified several residues important for dimer formation and enzymatic activity. Interestingly, the corresponding residues on DPP9 have a different impact whereby the mutations decrease activity without changing dimerization. Thus the propeller loop seems to play a varying role in different DPPs.
Related JoVE Video
Unrecognized vertebral body fractures (VBFs) in chest radiographic reports in Taiwan: a hospital-based study.
Arch Gerontol Geriatr
PUBLISHED: 08-08-2011
Show Abstract
Hide Abstract
Osteoporosis and its associated fragility fractures greatly impact the health-care system. VBF can be inadvertently overlooked on radiological examinations, which may delay diagnosis and treatment of osteoporosis. This hospital-based study evaluated chest radiographs to determine the prevalence rate of unrecognized VBF. Digitalized chest radiographs stored in the Taipei Veterans General Hospital Radiology Information System (TVGHRIS) were retrieved for study. One month of image data from 2009 was randomly obtained. All patients were over 55 years of age. Posterior-anterior (PA) and lateral chest radiographs were available for all patients. All selected chest radiographs were reviewed by two radiologists who were blinded to the official reports. Comparisons between official reports and the reference reports determined the prevalence of unrecognized VBF. Chest radiographs from 1655 patients (mean age 71.9 ± 10.4 years, 63.9% male) were reviewed. The prevalence of recognized VBF was significantly higher in consensus reports compared to the official reports (23.0% vs. 4.8%, p<0.001). Overall, 79% of VBFs were undiagnosed. The prevalence of unrecognized VBFs was 18.2% (19.6% in men, 15.7% in women). VBFs in men were more likely to be unrecognized than women (19.6% vs. 15.7%, p=0.04). Adjusted for age, gender was not an independent risk factor for unrecognized VBF in logistic regression. In conclusion, the high rate of unrecognized VBF in a tertiary medical center in Taiwan highlights the need to improve radiographic recognition of VBF, which could aid early treatment of osteoporosis in older adults.
Related JoVE Video
Giant branching aneurysmal aberrant systemic artery for intralobar pulmonary sequestration: computed tomographic depiction of arterial and bronchial anomaly.
J Chin Med Assoc
PUBLISHED: 08-02-2011
Show Abstract
Hide Abstract
Aberrant systemic arteries supplying the intralobar pulmonary sequestration can become dilated and have atherosclerotic change. Computed tomography is very useful in demonstrating the aberrant artery. We report a case of intralobar pulmonary sequestration with giant branching aneurysmal aberrant artery, and demonstrated the discontinuity of the bronchus by 64-slice computed tomography, which has not previously been described.
Related JoVE Video
Tannic acid suppresses ultraviolet B-induced inflammatory signaling and complement factor B on human retinal pigment epithelial cells.
Cell. Immunol.
PUBLISHED: 07-12-2011
Show Abstract
Hide Abstract
Ultraviolet B (UVB) radiation may cause the inflammation of retinal pigment epithelium (RPE) cells and play a role in development of age-related macular degeneration (AMD). The activation of the complement factor B (CFB) gene has been shown to be involved in formation of AMD. Here our results revealed that UVB induces IL-6/STAT3 signaling activation and the UVB-induced STAT3 is able to regulate the CFB expression in ARPE-19 cells. Tannic acid (TA) is a kind of water-soluble polyphenol and may have anti-inflammation effects. We also found that TA attenuates the UVB-induced IL-6 protein production, the STAT3 phosphorylation and the CFB expression. Taken together, these findings suggest UVB-induced inflammation of RPE can be mediated through the IL-6/STAT3/CFB pathway, and TA has a protected effect via the inhibition to the inflammatory response.
Related JoVE Video
Orai1/CRACM1 overexpression suppresses cell proliferation via attenuation of the store-operated calcium influx-mediated signalling pathway in A549 lung cancer cells.
Biochim. Biophys. Acta
PUBLISHED: 06-08-2011
Show Abstract
Hide Abstract
Orai1/CRACM1 is a principal component of the store-operated calcium channels. Store-operated calcium influx is highly correlated with inflammatory reactions, immunological regulation, and cell proliferation. Epidermal growth factor (EGF), which plays an important role in the regulation of cell proliferation, can activate store-operated calcium channels. However, the consequences of Orai1/CRACM1 overexpression in EGF-mediated lung cancer cells growth are not known.
Related JoVE Video
Jun dimerization protein 2 in oxygen restriction; control of senescence.
Curr. Pharm. Des.
PUBLISHED: 05-12-2011
Show Abstract
Hide Abstract
Senescent cells show a series of alterations, including a flat and enlarged morphology, increase in nonspecific acidic ?- galactosidase activity, chromatin condensation, and changes in gene expression patterns. The onset and maintenance of senescence are regulated by two tumor suppressor proteins, p53 and Rb, whose expression is controlled by two distinct proteins, p19(Arf) and p16(Ink4a), respectively, which are encoded by the cdkn2a locus. Transcription factor Jun dimerization protein 2 (JDP2) which binds directly to histones and DNA, inhibits the acetylation and methylation of core histones and of reconstituted nucleosomes that contain JDP2-recognition DNA sequences. JDP2-deficient mouse embryonic fibroblasts are known to be resistant to replicative senescence. Oxygen induces the expression of the JDP2 gene and JDP2 then inhibits the recruitment of polycomb repressive complexes (PRCs1 and 2) to the promoter of the gene encoding p16(Ink4a), resulting in the inhibition of methylation of lysine 27 of histone H3. These findings suggest that chromatin-remodeling factors, including the PRC complex controlled by JDP2, are important players in the senescence. The newly defined mechanisms that underlie the action of oxygen in the induction of JDP2 and cellular senescence are reviewed.
Related JoVE Video
Myocardial bridging in Taiwanese: noninvasive assessment by 64-detector row coronary computed tomographic angiography.
J Chin Med Assoc
PUBLISHED: 03-15-2011
Show Abstract
Hide Abstract
Myocardial bridging (MB) is a congenital structural variant in which a segment of the epicardial coronary artery tunnels into and is surrounded by the myocardium. MB has been correlated to some clinical complications of cardiovascular disease (CVD). The depiction rate of MB varies significantly between catheter coronary angiography and autopsy studies. This study aimed to assess the depiction rate of MB among Taiwanese by coronary computed tomographyic angiography (CCTA), to determine the anatomical features of the tunneling vessels, and to evaluate the outcome of patients having MB.
Related JoVE Video
Frequency and risk factors associated with atherosclerotic plaques in patients with a zero coronary artery calcium score.
J Chin Med Assoc
PUBLISHED: 01-31-2011
Show Abstract
Hide Abstract
Analysis of the coronary artery calcium levels usually provides important information that can be used in patient prognosis and stratification of treatment when coronary artery disease is suspected. However, plaques, with or without significant stenosis, have been reported in patients without coronary artery calcium. The aim of this study was to determine the frequency and risk factors of the development of coronary artery plaques in individuals with a zero calcium score.
Related JoVE Video
Clinical and pathological determinants in tonsillar cancer.
Head Neck
PUBLISHED: 01-31-2011
Show Abstract
Hide Abstract
The purpose of this study was to present the impact of clinicopathological factors on patient survival in tonsillar squamous cell carcinoma (SCC) that needs to be evaluated.
Related JoVE Video
BRAP Activates Inflammatory Cascades and Increases the Risk for Carotid Atherosclerosis.
Mol. Med.
PUBLISHED: 01-26-2011
Show Abstract
Hide Abstract
The BRCA-1 associated protein gene (BRAP) was recently identified as a susceptibility gene for myocardial infarction (MI). In the present study we aimed to decipher the association between the BRAP polymorphism and carotid atherosclerosis and the mechanism underlying its proatherogenic effect. A total of 1749 stroke/MI-free volunteers received carotid ultrasonic examinations for the measurement of intima-medial thickness (IMT) and plaque. The promoter polymorphism rs11066001 was selected because it affects the transcription of BRAP. We found that the GG genotype was associated with a 1.58-fold increased risk for having at least one plaque compared to carrying the A allele (P = 0.021). When subjects were divided by the cutoff value of IMT above the mean plus 1 standard deviation, there was an overrepresentation of the GG genotype in the subjects with thicker IMT (P = 0.004). The expression of BRAP increased significantly when human aortic smooth muscle cells (HASMCs) were treated with lipopolysaccharide (LPS). HASMCs were transfected with small interfering RNA against BRAP or scrambled sequences before treatment with LPS. Knockdown of BRAP led to attenuated HASMC proliferation and reduced secretion of monocyte chemoattractant protein-1 (MCP-1) and interleukin-8 (IL-8) in response to LPS. Downregulation of BRAP did not affect the protein levels of nuclear factor-?B (NF-?B), but prohibited its nuclear translocation. Coimmunoprecipitation experiments confirmed an interaction between BRAP and the two major components of the IKK signalosome, I?B? and IKK?. Collectively, BRAP conferred a risk for carotid plaque and IMT. Inflammatory stimuli upregulated BRAP expression, and BRAP activated inflammatory cascades by regulating NF-?B nuclear translocation.
Related JoVE Video
OxLDL up-regulates microRNA-29b, leading to epigenetic modifications of MMP-2/MMP-9 genes: a novel mechanism for cardiovascular diseases.
FASEB J.
PUBLISHED: 01-25-2011
Show Abstract
Hide Abstract
MicroRNAs (miRNAs), small noncoding RNAs, can control gene expression by binding to their target genes for degradation and/or translational repression. Epigenetic mechanisms are defined as heritable changes in gene expression that do not involve coding sequence modifications. Both mechanisms play an important role in maintaining physiological functions and are also related to disease development. However, few studies report that miRNA-mediated epigenetic regulations are involved in atherosclerosis. In the present study, oxidized low-density lipoprotein (oxLDL) significantly increased primary human aortic smooth muscle cell (HASMC) migration through MMP-2/MMP-9 up-regulation associated with decreased DNA methylation levels. Either mRNA or protein level of DNA methyltransferase 3b (DNMT3b) showed a dose-dependent down-regulation in oxLDL-mediated HASMCs. Knockdown DNMT3b expression enhanced oxLDL-induced DNA demethylation levels of MMP-2/MMP-9. The expression of miRNA-29b (miR-29b), directly targeting DNMT3b, was up-regulated by oxLDL treatment in a dose-dependent manner. OxLDL-mediated MMP-2/MMP-9 up-regulation, DNMT3b down-regulation, and DNA demethylation were all attenuated after knockdown miR-29b expression by antagomiR-29b. We find that oxLDL can up-regulate miR-29b expression, resulting in DNMT3b down-regulation in HASMCs and epigenetically regulated MMP-2/MMP-9 genes involved in cell migration. These results show that miRNA-mediated epigenetic regulation may be a novel mechanism in atherosclerosis.
Related JoVE Video
Interleukin-28B genetic variants in identification of hepatitis C virus genotype 1 patients responding to 24 weeks peginterferon/ribavirin.
J. Hepatol.
PUBLISHED: 01-11-2011
Show Abstract
Hide Abstract
A substantial proportion of hepatitis C virus genotype 1 (HCV-1) patients achieved a sustained virological response (SVR, HCV RNA seronegative throughout 24 weeks of post-treatment follow-up) after 24 weeks peginterferon/ribavirin therapy. We explored the role of interleukin-28B genotype in identifying patients who responded to the regimen.
Related JoVE Video
Application of persulfate to remediate petroleum hydrocarbon-contaminated soil: feasibility and comparison with common oxidants.
J. Hazard. Mater.
PUBLISHED: 01-06-2011
Show Abstract
Hide Abstract
In this study, batch experiments were conducted to evaluate the feasibility of petroleum-hydrocarbon contaminated soil remediation using persulfate oxidation. Various controlling factors including different persulfate and ferrous ion concentrations, different oxidants (persulfate, hydrogen peroxide, and permanganate), and different contaminants (diesel and fuel oil) were considered. Results show that persulfate oxidation is capable of treating diesel and fuel oil contaminated soil. Higher persulfate and ferrous ion concentrations resulted in higher diesel degrading rates within the applied persulfate/ferrous ion molar ratios. A two-stage diesel degradation was observed in the batch experiments. In addition, treatment of diesel-contaminated soil using in situ metal mineral activation under ambient temperature (e.g., 25°C) may be a feasible option for site remediation. Results also reveal that persulfate anions could persist in the system for more than five months. Thus, sequential injections of ferrous ion to generate sulfate free radicals might be a feasible way to enhance contaminant oxidation. Diesel oxidation efficiency and rates by the three oxidants followed the sequence of hydrogen peroxide>permanganate>persulfate in the limited timeframes. Results of this study indicate that the application of persulfate oxidation is a feasible method to treat soil contaminated by diesel and fuel oil.
Related JoVE Video
A functional polymorphism at 3UTR of the PAX6 gene may confer risk for extreme myopia in the Chinese.
Invest. Ophthalmol. Vis. Sci.
PUBLISHED: 01-01-2011
Show Abstract
Hide Abstract
The paired box 6 (PAX6) is involved in eye development and associated with several ocular diseases. Conflicting results have been reported regarding the association between PAX6 polymorphism and myopia. This case-control study and functional assay were conducted to identified a functional risk polymorphism for myopia.
Related JoVE Video
Primary orbital meningioma: a study of six cases at a single institution.
APMIS
PUBLISHED: 11-17-2010
Show Abstract
Hide Abstract
Primary orbital meningioma is a rare tumor of the anterior visual pathway and constitutes approximately 2% of all orbital tumors and 1-2% of all meningiomas. The differentiation from secondary orbital meningioma of intracranial origin is sometimes difficult on image. As the tumor often leads to visual loss if left untreated and surgical intervention inevitably causes morbidity, the timing and modality of treatment are very important. We carried out the study involving six cases (mean age: 42.7 years, male to female ratio: 1:5) of primary orbital meningioma to further elucidate its behavior. The clinical signs and symptoms, diagnosis, treatment strategies, and follow-up information are recorded for all cases. The most frequent initial symptoms were visual complaints (100%) and proptosis (67%). In five cases, the diagnosis was based on pathologic findings and the tumors were all grade I meningiomas. In one case, however, the diagnosis was based on radiographic and clinical findings, lacking histologic confirmation. Five patients were operated on, four underwent tumor removal, and one received eyeball exenteration. One patient was treated with Novalis radiotherapy. The mean follow-up period was 8.8 years (range from 9 months to 15 years). All patients experienced loss of vision during the course without exception. No recurrent tumor was found in five cases during follow-up. In case 5, whose eyeball was exenterated, developed recurrent meningioma 7 years later. She received radiotherapy but the tumor was out of control. She expired 8 years after eyeball exenteration. The primary orbital meningioma is aggressive in behavior despite its benign histopathologic features. Loss of vision is frequently seen even after treatment. The tumor could be fatal if surgery and radiotherapy fail to control its intracranial extension.
Related JoVE Video
Inorganic gyroid with exceptionally low refractive index from block copolymer templating.
Nano Lett.
PUBLISHED: 11-03-2010
Show Abstract
Hide Abstract
Nanoporous polymers with gyroid nanochannels can be fabricated from the self-assembly of degradable block copolymer, polystyrene-b-poly(l-lactide) (PS-PLLA), followed by the hydrolysis of PLLA blocks. A well-defined nanohybrid material with SiO2 gyroid nanostructure in a PS matrix can be obtained using the nanoporous PS as a template for sol-gel reaction. After subsequent UV degradation of the PS matrix, a highly porous inorganic gyroid network remains, yielding a single-component material with an exceptionally low refractive index (as low as 1.1).
Related JoVE Video
Control of petroleum-hydrocarbon contaminated groundwater by intrinsic and enhanced bioremediation.
J Environ Sci (China)
PUBLISHED: 10-07-2010
Show Abstract
Hide Abstract
In the first phase of this study, the effectiveness of intrinsic bioremediation on the containment of petroleum hydrocarbons was evaluated at a gasoline spill site. Evidences of the occurrence of intrinsic bioremediation within the BTEX (benzene, toluene, ethylbenzene, and xylenes) plume included (1) decreased BTEX concentrations; (2) depletion of dissolved oxygen (DO), nitrate, and sulfate; (3) production of dissolved ferrous iron, methane, and CO2; (4) deceased pH and redox potential; and (5) increased methanogens, total heterotrophs, and total anaerobes, especially within the highly contaminated areas. In the second phase of this study, enhanced aerobic bioremediation process was applied at site to enhance the BTEX decay rates. Air was injected into the subsurface near the mid-plume area to biostimulate the naturally occurring microorganisms for BTEX biodegradation. Field results showed that enhanced bioremediation process caused the change of BTEX removal mechanisms from anaerobic biodegradation inside the plume to aerobic biodegradation. This variation could be confirmed by the following field observations inside the plume due to the enhanced aerobic bioremediation process: (1) increased in DO, CO2, redox potential, nitrate, and sulfate, (2) decreased in dissolved ferrous iron, sulfide, and methane, (3) increased total heterotrophs and decreased total anaerobes. Field results also showed that the percentage of total BTEX removal increased from 92% to 99%, and the calculated total BTEX first-order natural attenuation rates increased from 0.0092% to 0.0188% per day, respectively, after the application of enhanced bioremediation system from the spill area to the downgradient area (located approximately 300 m from the source area).
Related JoVE Video
Conservative management of chronic gastric volvulus: 44 cases over 5 years.
World J. Gastroenterol.
PUBLISHED: 09-01-2010
Show Abstract
Hide Abstract
To investigate clinical outcomes of patients with chronic gastric volvulus (GV) who were managed conservatively over a 5-year period.
Related JoVE Video
Secondary ocular hypertension after intravitreal injection with 2 mg or 4 mg of triamcinolone in retinal vein occlusion.
J Ocul Pharmacol Ther
PUBLISHED: 07-27-2010
Show Abstract
Hide Abstract
To evaluate secondary ocular hypertension after intravitreal injection of triamcinolone acetonide (IVTA) with 2 mg/0.05 mL or 4 mg/0.1 mL for macular edema associated with retinal vein occlusion (RVO).
Related JoVE Video
Modified split-cast technique: a new, timesaving clinical remount technique.
J Prosthodont
PUBLISHED: 06-23-2010
Show Abstract
Hide Abstract
Interocclusal discrepancies can be eliminated by a clinical remount procedure, but most practitioners avoid it because of the time involved. This article introduces a new timesaving method, the modified split-cast technique. It uses a semi-adjustable articulator, tin foil as plaster separator, and an addition-type, silicone bite-registration material. The technician does most of the remounting procedures before the denture delivery appointment, so the dentist spends very little time chairside to complete the clinical remount procedure. Compared with the conventional and two other remounting techniques, the new technique is faster and easier to manipulate.
Related JoVE Video
Jun dimerization protein 2 controls senescence and differentiation via regulating histone modification.
J. Biomed. Biotechnol.
PUBLISHED: 06-10-2010
Show Abstract
Hide Abstract
Transcription factor, Jun dimerization protein 2 (JDP2), binds directly to histones and DNAs and then inhibits the p300-mediated acetylation both of core histones and of reconstituted nucleosomes that contain JDP2 recognition DNA sequences. JDP2 plays a key role as a repressor of adipocyte differentiation by regulation of the expression of the gene C/EBP? via inhibition of histone acetylation. Moreover, JDP2-deficient mouse embryonic fibroblasts (JDP2(-/-) MEFs) are resistant to replicative senescence. JDP2 inhibits the recruitment of polycomb repressive complexes (PRC1 and PRC2) to the promoter of the gene encoding p16(Ink4a), resulting from the inhibition of methylation of lysine 27 of histone H3 (H3K27). Therefore, it seems that chromatin-remodeling factors, including the PRC complex controlled by JDP2, may be important players in the senescence program. The novel mechanisms that underline the action of JDP2 in inducing cellular senescence and suppressing adipocyte differentiation are reviewed.
Related JoVE Video
Clear cell meningioma with frequent chordoid features and aggressive behavior: a clinicopathologic study of ten cases at a single institution.
J. Neurooncol.
PUBLISHED: 06-01-2010
Show Abstract
Hide Abstract
Clear cell meningioma is an uncommon variant of meningiomas that often occurs in young patients, shows a proclivity for spinal intradural extramedullary and cerebellopontine angle, and follows an aggressive clinical course. We render clinicopathologic features of ten cases of this rare tumor to further elucidate its behavior. Fifteen specimens of clear cell meningioma belonging to ten patients were obtained at a single institution from 2001 to 2009. Correlations of histologic parameters, immunohistochemical study, and clinical features were assessed. This series included eight men and two women with a mean age of 62.1 years at the first surgery. The mean post-operative follow-up period was 3.9 years. Four patients (40%) had single or multiple local tumor recurrences. The mean time to recurrence was 2.3 years. Seven tumors (46.7%) were combined with chordoid features. There was a wide range of MIB-1 labeling indices (4.4-33.5%, mean 15.8%), which were higher in recurrent tumors, tumors with chordoid features, and tumors with necrosis. There was no correlation between MIB-1 labeling indices and brain invasion. The study illustrates aggressive behavior of clear cell meningioma and frequently combined chordoid features in our cases.
Related JoVE Video
Taiwan cobra phospholipase A2 elicits posttranscriptional up-regulation of ADAM17 in human neuroblastoma SK-N-SH cells.
J. Cell. Biochem.
PUBLISHED: 05-28-2010
Show Abstract
Hide Abstract
Taiwan cobra phospholipase A(2) (PLA(2)) treatment promoted proADAM17 processing into mature ADAM17 in human neuroblastoma SK-N-SH cells. The abolishment of catalytic activity caused a drastic drop in the PLA(2) ability to induce ADAM17 maturation, and lysophosphatidylcholine treatment mimicked the effect of PLA(2). ADAM17 activity measurement, ADAM17 cell surface levels, TNFR2 ectodomain shedding, and ADAM17 mRNA transcription supported that posttranscriptional up-regulation of ADAM17 occurred in PLA(2)-treated SK-N-SH cells. PLA(2) treatment induced p38 MAPK activation and ERK inactivation. p38 MAPK activation suppression by SB202190 (p38 MAPK inhibitor) abolished posttranscriptional up-regulation of ADAM17 in PLA(2)-treated cells, while treatment with U0126 (MEK1 and MEK2 inhibitor) increased ADAM17 maturation in SK-N-SH cells. Constitutively active MEK1 expression abrogated PLA(2)-induced ADAM17 maturation. Taken together, our data indicate that PLA(2)-evoked p38 MAPK activation and ERK inactivation are involved in ADAM17 posttranscriptional up-regulation, and suggest that the action of PLA(2) is catalytic activity-dependent.
Related JoVE Video
Green tea epigallocatechin gallate inhibits insulin stimulation of adipocyte glucose uptake via the 67-kilodalton laminin receptor and AMP-activated protein kinase pathways.
Planta Med.
PUBLISHED: 05-07-2010
Show Abstract
Hide Abstract
Insulin and (-)-epigallocatechin gallate (EGCG) are reported to regulate obesity and fat accumulation, respectively. This study investigated the pathways involved in EGCG modulation of insulin-stimulated glucose uptake in 3T3-L1 and C3H10T1/2 adipocytes. EGCG inhibited insulin stimulation of adipocyte glucose uptake in a dose- and time-dependent manner. The concentration of EGCG that decreased insulin-stimulated glucose uptake by 50-60% was approximately 5-10?µM for a period of 2 h. At 10?µM, EGCG and gallic acid were more effective than (-)-epicatechin, (-)-epigallocatechin, and (-)-epicatechin 3-gallate. We identified the EGCG receptor [also known as the 67-kDa laminin receptor (67LR)] in fat cells and extended the findings for this study to clarify whether EGCG-induced changes in insulin-stimulated glucose uptake in adipocytes could be mediated through the 67LR. Pretreatment of adipocytes with a 67LR antibody, but not normal rabbit immunoglobulin, prevented the effects of EGCG on insulin-increased glucose uptake. This suggests that the 67LR mediates the effect of EGCG on insulin-stimulated glucose uptake in adipocytes. Moreover, pretreatment with an AMP-activated protein kinase (AMPK) inhibitor, such as compound C, but not with a glutathione (GSH) activator, such as N-acetyl-L-cysteine (NAC), blocked the antiinsulin effect of EGCG on adipocyte glucose uptake. These data suggest that EGCG exerts its anti-insulin action on adipocyte glucose uptake via the AMPK, but not the GSH, pathway. The results of this study possibly support that EGCG mediates fat content.
Related JoVE Video
Role of Doppler sonography in the diagnosis of pulmonary sequestration in an elderly patient: a case report.
J Clin Ultrasound
PUBLISHED: 04-06-2010
Show Abstract
Hide Abstract
An 83-year-old man presented with an asymptomatic mass-like lesion in left lower lobe on chest radiograph and CT, with no change over the past 7 years. Because of discrepancy between clinical and radiological manifestations, chest color Doppler sonography was done and identified a large tortuous pulsating vessel with systemic arterial waveform flowing toward the probe and entering the lesion at its apex. Subsequent contrast-enhanced reconstructed CT scans of the chest with angiography confirmed the diagnosis of intralobar pulmonary sequestration.
Related JoVE Video
Anisakis simplex (Nematoda: Anisakidae) third-stage larval infections of marine cage cultured cobia, Rachycentron canadum L., in Taiwan.
Vet. Parasitol.
PUBLISHED: 03-08-2010
Show Abstract
Hide Abstract
The first confirmed case of Anisakis simplex infection of the marine cage cobia, Rachycentron canadum (L.), was recorded in Taiwan. The case investigation revealed the presence of third-stage larvae (L3) in either the stomach lumen or abdominal cavity of the cobia but never within the musculatures. Larvae were mainly encapsulated in the peritoneal mesentery on the outer surface of the stomach wall and occasionally on the liver surface. Part of the diet fed to the cobia includes chopped raw fish, and of these, seven species were found to harbor these larvae (as paratenic hosts), indicating that these particular fish might be the larval sources for this infection. To illustrate the course of infection and distribution of this parasite inside cobia, both juvenile and adult cobia were experimentally infected with live L3 by oral transmission. The prevalence of infection reached 100% at the end of all trials. The course of the infection was assessed after necropsy by histological and ultrastructural observations. A. simplex L3 recovered from various locations within juvenile cobia at different post-infection (p.i.) times were at the L3 stage and did not grow significantly. The L3 either adhered to or penetrated into the gastric mucosa of cobia by 2 h p.i. By 25 d p.i., many were trapped within the submucosa and encapsulated by fibroconnective tissue. This phenomenon was more apparent in adult cobia, such that 37.5-86.0% of the injected L3 were primarily found encapsulated within the gastric submucosa. Based upon a PCR-RFLP assay, the larvae encountered in this study were identified as having a recombinant genotype of A. simplex sensu stricto and A. pegreffii. Based upon the results of this study, strategies to ensure the safety of seafood manufactured from cobia and to prevent the potential risks of anisakiasis or allergies risk to consumers were suggested.
Related JoVE Video
Factors influencing the presence of interproximal dental papillae between maxillary anterior teeth.
J. Periodontol.
PUBLISHED: 02-16-2010
Show Abstract
Hide Abstract
The presence of interdental papillae in the maxillary anterior region plays a key esthetic role. The aim of this study is to investigate the impact of demographic variables, such as gender and ages, and radiographic measurements of interdental area anatomy on the presence of interdental papillae.
Related JoVE Video
Correlates of institutionalized senior veterans quality of life in Taiwan.
Health Qual Life Outcomes
PUBLISHED: 01-17-2010
Show Abstract
Hide Abstract
Senior veterans living in government sponsored, long-term care (LTC) facilities, known as veterans homes (VHs), are a special minority group in Taiwan. These seniors came from different provinces of mainland China during their teenage years at the end of civil wars in 1945. The situation of institutionalized senior veterans shares many characteristics with the concept of "total institution". Very little quality of life (QOL) research has involved senior veterans. This study aimed to explore the QOL and related factors of VH-dwelling senior veterans in Taiwan.
Related JoVE Video
Block copolymers with a twist.
J. Am. Chem. Soc.
PUBLISHED: 12-24-2009
Show Abstract
Hide Abstract
Chiral block copolymers (BCPs*) comprising chiral entities were designed to fabricate helical architectures (i.e., twisted morphologies) from self-assembly. A new helical phase (H*) with P622 symmetry was discovered in the self-assembly of poly(styrene)-b-poly(l-lactide) (PS-PLLA) BCPs*. Hexagonally packed, interdigitated PLLA helical microdomains in a PS matrix were directly visualized by electron tomography. The phase diagram of the PS-PLLA BCPs* was also established. Phase transitions from the H* phase to the stable cylinder and gyroid phases were found after long-time annealing, suggesting that the H* is a long-lived metastable phase. In contrast to racemic poly(styrene)-b-poly(d,l-lactide) BCPs, chiral interaction significantly enhances the incompatibility between achiral PS and chiral PLLA blocks in the PS-PLLA BCPs* and can be estimated through the determination of the interaction parameter.
Related JoVE Video
Synchronous presentation of uterine leiomyosarcoma and retroperitoneal liposarcoma: analysis by comparative genomic hybridization and review of the literature.
Int. J. Gynecol. Pathol.
PUBLISHED: 10-24-2009
Show Abstract
Hide Abstract
Multiple primary malignant neoplasms are not uncommon, whereas 2 different types of primary sarcomas simultaneously presenting in 1 individual is quite unusual. We encountered a patient presenting with a uterine sarcoma and another retroperitoneal mass at the same time. These 2 tumors showed distinct pathologic and immunohistochemical features. The diagnosis of a synchronous presentation of a uterine leiomyosarcoma and a retroperitoneal sclerosing well-differentiated liposarcoma was rendered. Further study by comparative genomic hybridization showed unrelated genomic alterations of these 2 tumors. Nevertheless, other common genetic alterations such as balanced translocations, point mutations, or epigenetic modifications could still exist because of the limitation of findings by comparative genomic hybridization. In conclusion, both metastasis and multiple primary tumors should always be taken into consideration in differential diagnosis while encountering synchronous sarcomas.
Related JoVE Video
Enhancing electron collection efficiency and effective diffusion length in dye-sensitized solar cells.
Chemphyschem
PUBLISHED: 09-25-2009
Show Abstract
Hide Abstract
Intensity-modulated photocurrent spectroscopy and intensity-modulated photovoltage spectroscopy are employed to measure the dynamics of electron transport and recombination in the ZnO nanowire (NW) array-ZnO/layered basic zinc acetate (LBZA) nanoparticle (NP) composite dye-sensitized solar cells (DSSCs). The roles of the vertical ZnO NWs and insulating LBZA in the electron collection and transport in DSSCs are investigated by comparing the results to those in the TiO(2)-NP, horizontal TiO(2)-NW and vertical ZnO-NW-array DSSCs. The electron transport rate and electron lifetime in the ZnO NW/NP composite DSSC are superior to those in the conventional TiO(2)-NP cell due to the existence of the vertical ZnO NWs and insulating LBZA. It indicates that the ZnO NW/NP composite anode is able to sustain efficient electron collection over much greater thickness than the TiO(2)-NP cell does. Consequently, a larger effective electron diffusion length is available in the ZnO composite DSSC.
Related JoVE Video
Functional roles of EF-hands in human potassium channel-interacting protein 2.2.
Protein Pept. Lett.
PUBLISHED: 09-01-2009
Show Abstract
Hide Abstract
Single site-directed mutations at each of the four EF-hand loops of potassium channel-interacting protein 2.2 (KChIP2.2) were carried out to explore the functional roles of EF-hands in KChIP2.2. In contrast to those on EF-hands 1 and 2, mutations on EF-hands 3 or 4 distorted the high affinity Ca(2+)-binding site of KChIP2.2. However, the Mg(2+)-binding ability of KChIP2.2 was marginally affected by the mutations. The gross conformation of mutated KChIP2.2 was indistinguishable from wild-type KChIP2.2 as revealed by CD spectra. The results of size exclusion chromatography showed that, with exception of EF-hand 4 mutant, mutations on EF-hands 1, 2 or 3 caused KChIP2.2 to form oligomer. Pull-down assay revealed that, unlike wild-type KChIP2.2, the interaction between mutated KChIP2.2 and Kv4.2 was not notably enhanced by Ca(2+) and Mg(2+). Coexpression of Kv4.2 and KChIP2.2 in HeLa cells revealed that mutations on EF-hands did not alter the intracellular co-localization of KChIP2.2 and Kv4.2. Together with previous findings that EF-hand mutants of KChIP proteins are unable to regulate the kinetics of Kv4.2, our data show that the intact EF-hands should be crucial for the formation of active conformation of KChIP2.2 when the protein is loaded with Ca(2+) and Mg(2+).
Related JoVE Video

What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

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.