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Find video protocols related to scientific articles indexed in Pubmed.
[Identification of Pantoea agglomeran XM2 with biocontrol activity against postharvest pear black spot].
Wei Sheng Wu Xue Bao
PUBLISHED: 10-03-2014
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We isolated the bacterial strain XM2 from prunes (Prunus domestica L.) fruit surface. XM2 was identified and tested as an antagonist for postharvest biological control of black spot disease (Alternaria alternata) on pear fruits.
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Axonal regeneration and remyelination evaluation of chitosan/gelatin-based nerve guide combined with transforming growth factor-?1 and Schwann cells.
Cell Biochem. Biophys.
PUBLISHED: 09-24-2014
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Despite efforts in peripheral nerve injury and regeneration, it is difficult to achieve a functional recovery following extended peripheral nerve lesions. Even if artificial nerve conduit, cell components and growth factors can enhance nerve regeneration, integration in peripheral nerve repair and regeneration remains yet to be explored. For this study, we used chitosan/gelatin nerve graft constructed with collagenous matrices as a vehicle for Schwann cells and transforming growth factor-?1 to bridge a 10-mm gap of the sciatic nerve and explored the feasibility of improving regeneration and reinnervation in rats. The nerve regeneration was assessed with functional recovery, electrophysiological test, retrograde labeling, and immunohistochemistry analysis during the post-operative period of 16 weeks. The results showed that the internal sides of the conduits were compact enough to prevent the connective tissues from ingrowth. Nerve conduction velocity, average regenerated myelin area, and myelinated axon count were similar to those treated with autograft (p > 0.05) but significantly higher than those bridged with chitosan/gelatin nerve graft alone (p < 0.05). Evidences from retrograde labeling and immunohistochemistry analysis are further provided in support of improving axonal regeneration and remyelination. A designed graft incorporating all of the tissue-engineering strategies for peripheral nerve regeneration may provide great progress in tissue engineering for nerve repair.
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Phylogeography and evolution of a fungal-insect association on the Tibetan Plateau.
Mol. Ecol.
PUBLISHED: 09-18-2014
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Parasitoidism refers to a major form of interspecies interactions where parasitoids sterilize and/or kill their hosts typically before hosts reach reproductive age. However, relatively little is known about the evolutionary dynamics of parasitoidism. Here, we investigate the spatial patterns of genetic variation of Chinese cordyceps, including both the parasitoidal fungus Ophiocordyceps sinensis and its host insects. We sampled broadly from alpine regions on the Tibetan Plateau and obtained sequences on seven fungal and three insect DNA fragments from each of the 125 samples. Seven and five divergent lineages/cryptic species were identified within the fungus and host insects, respectively. Our analyses suggested that O. sinensis and host insects originated at similar geographic regions in southern Tibet/Yunnan, followed by range expansion to their current distributions. Cophylogenetic analyses revealed a complex evolutionary relationship between O. sinensis and its host insects. Significant congruence was found between host and parasite phylogenies and the time estimates of divergence were similar, raising the possibility of the occurrence of cospeciation events, but the incongruences suggested that host shifts were also prevalent. Interestingly, one fungal genotype was broadly distributed, consistent with recent gene flow. In contrast, the high-frequency insect genotypes showed limited geographic distributions. The dominant genotypes from both the fungus and the insect hosts may represent ideal materials from which to develop artificial cultivation of this important Chinese traditional medicine. Our results demonstrate that both historical and contemporary events have played important roles in the phylogeography and evolution of the O. sinensis-ghost moth parasitoidism on the Tibetan Plateau.
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[Application of multi-level model in study of relationship between soil cadmium contamination and people's urinary cadmium level].
Zhonghua Yu Fang Yi Xue Za Zhi
PUBLISHED: 09-16-2014
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Based on the characteristics of hierarchical data, a multilevel model was used to analysis possible influencing factors of urinary cadmium levels in one county population, and to discuss the advantages of multilevel model for processing hierarchical data in practical problems.
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Discovery of a biomarker and lead small molecules to target r(GGGGCC)-associated defects in c9FTD/ALS.
Neuron
PUBLISHED: 08-14-2014
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A repeat expansion in C9ORF72 causes frontotemporal dementia and amyotrophic lateral sclerosis (c9FTD/ALS). RNA of the expanded repeat (r(GGGGCC)exp) forms nuclear foci or undergoes repeat-associated non-ATG (RAN) translation, producing "c9RAN proteins." Since neutralizing r(GGGGCC)exp could inhibit these potentially toxic events, we sought to identify small-molecule binders of r(GGGGCC)exp. Chemical and enzymatic probing of r(GGGGCC)8 indicate that it adopts a hairpin structure in equilibrium with a quadruplex structure. Using this model, bioactive small molecules targeting r(GGGGCC)exp were designed and found to significantly inhibit RAN translation and foci formation in cultured cells expressing r(GGGGCC)66 and neurons transdifferentiated from fibroblasts of repeat expansion carriers. Finally, we show that poly(GP) c9RAN proteins are specifically detected in c9ALS patient cerebrospinal fluid. Our findings highlight r(GGGGCC)exp-binding small molecules as a possible c9FTD/ALS therapeutic and suggest that c9RAN proteins could potentially serve as a pharmacodynamic biomarker to assess efficacy of therapies that target r(GGGGCC)exp.
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Investigation of the role of organic cation transporter 2 (OCT2) in the renal transport of guanfacine, a selective ?2A-adrenoreceptor agonist.
Xenobiotica
PUBLISHED: 08-13-2014
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Abstract 1.? Guanfacine is a selective ?2A-adrenoreceptor agonist primarily excreted as its unchanged form through urine in human. This study was to investigate the involvement of organic cation transporter 2 (OCT2) in the renal tubular secretion of guanfacine. 2.? Transport of guanfacine was characterized using human embryonic kidney (HEK293) cells expressing human OCT2 (hOCT2). The inhibitory effect of cimetidine on guanfacine uptake was also examined. In addition, in vivo pharmacokinetic study was conducted in rats to assess the effects of cimetidine on the pharmacokinetics of guanfacine. 3.? The accumulation of guanfacine in hOCT2-transfected HEK293 cells was both time- and concentration-dependent, and markedly higher than that in mock cells. The apparent Km and Vmax values of guanfacine uptake by hOCT2 were 96.19?±?7.49??M and 13.03?±?0.49?nmol/mg protein/min, respectively. Guanfacine transport mediated by hOCT2 was significantly inhibited by a typical OCT2 inhibitor cimetidine with an IC50 value of 93.82?±?1.13??M. Co-administration of cimetidine significantly decreased the plasma clearance (CLp) as well as the renal clearance (CLr) of guanfacine in rats in a dose-dependent manner, resulting in a noticeable increase in the systemic exposure of guanfacine. 4.? These results indicated that OCT2 may be involved in the renal disposition of guanfacine.
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Tissue-Engineered Nerve Constructs Under a Microgravity System for Peripheral Nerve Regeneration.
Tissue Eng Part A
PUBLISHED: 08-05-2014
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Mesenchymal stem cells (MSCs) seeded in a 3D scaffold often present characteristics of low proliferation and migration, which affect the microstructure of tissue-engineered nerves (TENs) and impair the therapeutic effects of nerve defects. By promoting MSC differentiation and mass/nutrient transport, rotary cell culture systems (RCCSs) display potential for advancing the construction of MSC-based TENs. Thus, in this study, we attempted to construct a TEN composed of adipose-derived mesenchymal stem cells (ADSCs) and acellular nerve graft (ANG) utilizing an RCCS. Compared to TENs prepared in a static 3D approach, MTT and cell count results displayed an increased number of ADSCs for TENs in an RCCS. The similarity in cell cycle states and high rates of apoptosis in the static 3D culture demonstrated that the higher proliferation in the RCCS was not due to microgravity regulation but a result of preferential mass/nutrient transport. Quantitative PCR and ELISA indicated that the RCCS promoted the expression of ADSC neural differentiation-associated genes compared to the static 3D culture. Furthermore, this difference was eliminated by adding the Notch1 signaling pathway inhibitor DAPT to the 3D static culture. TEM, axon immunostaining, and retrograde labeling analysis after sciatic nerve transplantation indicated that the TENs prepared in the RCCS exhibited more regenerative characteristics for repairing peripheral nerves than those prepared in a static 3D approach. Therefore, these findings suggest that the RCCS can modulate the construction, morphology, and function of engineered nerves as a promising alternative for nerve regeneration.
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Effect evaluation of vascular resection for patients with hilar cholangiocarcinoma: original data and meta-analysis.
Hepatogastroenterology
PUBLISHED: 06-06-2014
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To evaluate the effect of vascular resection (VR) in surgical management of hilar cholangiocarcinoma (HCCA), this report did a clinical analysis and conducted a systematic review, combined other studies, based on meta-analysis.
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Ecto-mesenchymal stem cells from facial process: potential for muscle regeneration.
Cell Biochem. Biophys.
PUBLISHED: 04-22-2014
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Ecto-mesenchymal stem cells (EMSCs) originate from the cranial neural crest and participate in the formation of tooth, salivary, and muscle in early development stage. The transplantation of EMSCs, a potential source of myoblast stem cell, might improve muscle regeneration. The purpose of this study was to explore whether EMSCs have the potential to differentiate and display a myogenic phenotype in vitro the in vitro. Here, we characterized the EMSCs isolated from the facial process, and p75 + EMSCs were collected by a FACS calibur flow cytometer. In vitro, p75 + EMSCs induced by DMSO can accumulate and fuse into multinucleated myotubes and further differentiate into the skeletal muscle cells in form of cell sheet. Functional myoblast phenotypes of p75 + EMSCs were found in vivo model of muscle injury. The remarkable ability of stem cells to regenerate skeletal muscle indicated their potential role in the cell therapy and tissue engineering of the skeletal muscle.
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Mesenchymal stem cells prevent hypertrophic scar formation via inflammatory regulation when undergoing apoptosis.
J. Invest. Dermatol.
PUBLISHED: 03-03-2014
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The cutaneous wound-healing process can lead to hypertrophic scar formation, during which exaggerated inflammation has been demonstrated to have an important role. Therefore, an exploration of strategies designed to regulate this inflammatory process is warranted. Mesenchymal stem cells (MSCs) have recently been demonstrated to regulate inflammation in various diseases. In this regard, using a rabbit model, we locally injected human mesenchymal stem cells (hMSCs) derived from bone marrow to treat hypertrophic scar formation, and explored their underlying mechanisms. We found that hMSC therapy efficiently regulated inflammation and prevented scar formation. We attributed the therapeutic effects of hMSCs to their secretion of an anti-inflammatory protein, TNF-alpha-stimulated gene/protein 6 (TSG-6). Unexpectedly, after injection, the number of surviving hMSCs decreased markedly and the hMSCs underwent extensive apoptosis, which was demonstrated to promote their secretion of TSG-6, partially through the activation of caspase-3. Moreover, H2O2-induced apoptotic hMSCs showed higher inflammatory regulatory abilities. The inhibition of caspase-3 decreased the inflammatory regulatory abilities of hMSCs and attenuated their therapeutic effects. Our results demonstrate that hMSCs can efficiently prevent hypertrophic scar formation via inflammatory regulation. In addition, we found that apoptosis has an important role in the activation of the inflammatory regulatory abilities of hMSCs.
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Investigation on pharmacokinetics, tissue distribution and excretion of a novel platinum anticancer agent in rats by inductively coupled plasma mass spectrometry (ICP-MS).
Xenobiotica
PUBLISHED: 02-14-2014
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1.?DN604 is a new platinum agent with encouraging anticancer activity. The present study was to explore the pharmacokinetic profiles, distribution and excretion of platinum in Sprague-Dawley rats after intravenous administration of DN604. A sensitive and selective inductively coupled plasma mass spectrometry (ICP-MS) method was established for determination of platinum in biological specimens. The pharmacokinetic parameters were calculated by a non-compartmental method. 2.?The area under concentration-time curve AUC0-t and AUC0-? for platinum originating from DN604 at 10?mg/kg were 25.15?±?1.29 and 28.72?±?1.04??g/hml, respectively. The mean residence time MRT was 36.59?±?6.65?h. The volume of distribution Vz was 11.42?±?2.49?l/kg and clearance CL was 0.18?±?0.01?l/h/kg. In addition, the elimination half-life T1/2z was 44.83?±?9.75?h. After intravenous administration of DN604, platinum was extensively distributed in most of tested tissues except brain. The majority of platinum excreted via urine, and its accumulative excretion ratio during the period of 120?h was 63.5%?±?7.7% for urine, but only 6.94%?±?0.11% for feces. 3.?The satisfactory half-life, wide distribution and high excretion made this novel platinum agent worthy of further research and development.
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Effect evaluation of vascular resection for patients with hilar cholangiocarcinoma: original data and meta-analysis.
Cell Biochem. Biophys.
PUBLISHED: 02-11-2014
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To evaluate the effect of vascular resection (VR) in surgical management of hilar cholangiocarcinoma (HCCA), this report is used in a clinical analysis and conducted a systematic review, combined other studies, based on meta-analysis. 238 HCCA patients underwent hepatectomy in the Eastern Hepatobiliary Surgery Hospital. Binary logistic regression analysis was performed to investigate the potentially complicated associated factors. Kaplan-Meier test was employed to compare the long-term survival of patients in four groups (R0+PVR-free, R0+PVR, R1, and R2). Meta-analysis was performed using RevMan 4.3.2 software. The results suggested that hepatectomy and HAR were important negative factors from complications (p < 0.01). Compared with patients in other groups, survival of patients in R0+PVR group was worse than R0+PVR-free group, better than R2 group, and similar to R1group with p = 0.001, 0.047, and 0.606, respectively. The results of meta-analysis suggested patients who underwent VR had higher complications rate and mortality rate than patients who did not. Moreover, patients with vascular resection had lower long-term survival rate. VR used to be considered effective to the patients with vascular invasion. However, our study suggests that the surgical decision of undergoing VR should be made cautiously, since VR could diminish the survival time in some cases.
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TGF-? upregulates miR-182 expression to promote gallbladder cancer metastasis by targeting CADM1.
Mol Biosyst
PUBLISHED: 01-21-2014
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Transforming growth factor ? (TGF-?) plays important roles in tumor metastasis by regulating miRNAs expression. miR-182 is an important molecule in the regulation of cancer progression. The aim of the study is to assess the role of miR-182 in TGF-?-induced cancer metastasis. In the present study, we found that miR-182 levels are significantly upregulated in GBC tissues compared with normal controls, and miR-182 expression is remarkably increased in primary tumors that subsequently metastasized, when compared to those primary tumors that did not metastasize. TGF-? induces miR-182 expression in GBC cells, and overexpression of miR-182 promotes GBC cell migration and invasion, whereas miR-182 inhibition suppresses TGF-?-induced cancer cell migration and invasion. The blockage of miR-182 by a specific inhibitor effectively inhibits pulmonary metastases in vivo. We further identified that the cell adhesion molecule1 (CADM1) is a new target gene of miR-182. miR-182 negatively regulates CADM1 expression in vitro and in vivo. Importantly, re-expression of CADM1 in GBC cells partially abrogates miR-182-induced cell invasion.
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Casein kinase II induced polymerization of soluble TDP-43 into filaments is inhibited by heat shock proteins.
PLoS ONE
PUBLISHED: 01-01-2014
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Trans-activation Response DNA-binding Protein-43 (TDP-43) lesions are observed in Amyotrophic Lateral Sclerosis (ALS), Frontotemporal Lobar Degeneration with ubiquitin inclusions (FTLD-TDP) and 25-50% of Alzheimer's Disease (AD) cases. These abnormal protein inclusions are composed of either amorphous TDP-43 aggregates or highly ordered filaments. The filamentous TDP-43 accumulations typically contain clean 10-12 nm filaments though wider 18-20 nm coated filaments may be observed. The TDP-43 present within these lesions is phosphorylated, truncated and ubiquitinated, and these modifications appear to be abnormal as they are linked to both a cellular heat shock response and microglial activation. The mechanisms associated with this abnormal TDP-43 accumulation are believed to result in a loss of TDP-43 function, perhaps due to the post-translational modifications or resulting from physical sequestration of the TDP-43. The formation of TDP-43 inclusions involves cellular translocation and conversion of TDP-43 into fibrillogenic forms, but the ability of these accumulations to sequester normal TDP-43 and propagate this behavior between neurons pathologically is mostly inferred. The lack of methodology to produce soluble full length TDP-43 and recapitulate this polymerization into filaments as observed in disease has limited our understanding of these pathogenic cascades.
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Multi-core CPU or GPU-accelerated Multiscale Modeling for Biomolecular Complexes.
Mol Based Math Biol
PUBLISHED: 12-20-2013
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Multi-scale modeling plays an important role in understanding the structure and biological functionalities of large biomolecular complexes. In this paper, we present an efficient computational framework to construct multi-scale models from atomic resolution data in the Protein Data Bank (PDB), which is accelerated by multi-core CPU and programmable Graphics Processing Units (GPU). A multi-level summation of Gaus-sian kernel functions is employed to generate implicit models for biomolecules. The coefficients in the summation are designed as functions of the structure indices, which specify the structures at a certain level and enable a local resolution control on the biomolecular surface. A method called neighboring search is adopted to locate the grid points close to the expected biomolecular surface, and reduce the number of grids to be analyzed. For a specific grid point, a KD-tree or bounding volume hierarchy is applied to search for the atoms contributing to its density computation, and faraway atoms are ignored due to the decay of Gaussian kernel functions. In addition to density map construction, three modes are also employed and compared during mesh generation and quality improvement to generate high quality tetrahedral meshes: CPU sequential, multi-core CPU parallel and GPU parallel. We have applied our algorithm to several large proteins and obtained good results.
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Effect of triacontanol on the pharmacokinetics of docetaxel in rats associated with induction of cytochrome P450 3A1/2.
Xenobiotica
PUBLISHED: 12-13-2013
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Abstract 1.? Triacontanol was confirmed to have a potential anti-cancer effect, the aim was to assess whether the co-administration of triacontanol alters the exposure of docetaxel via inducing hepatic CYP3A1/2 activity. The concentration of docetaxel in rats pretreated with triacontanol for seven successive days was determined, and the expression levels of CYP3A protein and mRNA were analyzed by the western blot and real time polymerase chain reaction (RT-PCR) technique, respectively. 2.? The concentrations of docetaxel in rats pretreated with triacontanol were decreased, with 61.5%, 61.9% decrease in AUC0-24h and 65.7%, 54.9% reduction in Cmax (120 and 180?mg?kg(-1), respectively) compared with the control. Hepatic clearance of docetaxel was enhanced in vitro and in vivo at dosage of 120 and 180?mg?kg(-1), and CYP3A activity was up-regulated by measuring the formation rate of 1-hydroxymidazolam. Triacontanol preferentially induced protein expression level of CYP3A2 in a dose-dependent manner and of CYP 3A1 at dosage of 120 and 180?mg?kg(-1). The mRNA expression of CYP3A1 was moderately different with the western blot results, but the trends appeared similar. CYP3A2 mRNA level was not markedly affected by triacontanol. 3.? The significant triacontanol-docetaxel interaction was largely due to the induction of CYP3A1/2, which brought useful information in the clinical therapy when the combination is administered in human.
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Clinical and radiological characteristics of Chinese patients with hepatic epithelioid hemangioendothelioma.
Ann Saudi Med
PUBLISHED: 09-25-2013
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To study clinical features, imaging findings, and prognosis of hepatic epithelioid hemangioendothelioma (HEHE) in Eastern Hepatobiliary Surgical Hospital and to improve the level of recognition and preoperative diagnosis of HEHE.
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Integration of a calcined bovine bone and BMSC-sheet 3D scaffold and the promotion of bone regeneration in large defects.
Biomaterials
PUBLISHED: 07-10-2013
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Reconstruction of large area bone defect with mechanical integrity to the skeleton is important for patients rehabilitation. However with the limitation of scaffold material and suitable seed cell sources, the best treating strategy remains to be identified though various tissue engineering methods were reported. In this study, we investigated the feasibility of applying calcined bovine bone (CBB) which was coated by allograft bone marrow mesenchymal stem cells (BMSC)-sheet as a 3D scaffold material in bone repairing tissue engineering. The new scaffold material was implanted into osteoporosis rat cranial bone defects and repairing critical size bone defects (8 mm diameter). Data showed that CBB-BMSC-sheet combination had a stronger potential in osteogenic differentiation and mineralized formation both in vitro and in vivo than CBB-BMSC combination. In in vitro study BMSC-sheet had a more feasible characteristic upon bone repairing including richer ECM, larger mineralized area and stronger ALP activity in addition with a significant higher mRNA expression of osteogenic maker such as BMP-2, b-FGF, Col 1a1, OSX and Runx-2 than the control group. In in vivo study 3D reconstruction of micro CT, HE staining and bone strength results showed that newly formed bone in CBB-BMSC-sheet group was significant higher than that in CBB-BMSC group at 4, 8 and 12 weeks after transplantation in the aspect of area and volume. What was more, results indicated that allograft BMSC-sheet had survivaled in the scaffold material and participated in the newly formed bone which had the same thickness with surrounding autologous bone tissues after transplantation. Results of our study demonstrated that CBB-BMSC-sheet combination was a promising strategy in healing of large area bone defect in osteoporosis.
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A new method of microskin autografting with a Vaseline-based moisture dressing on granulation tissue.
Burns
PUBLISHED: 07-03-2013
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In the conventional method of microskin autografting, aggressive early excision is adopted, followed by coverage with a microskin-allograft complex to close extensive burn wounds. However, early excision is always associated with a defect of viable tissue, resulting in massive blood loss and causing high risk to aged patients or those with other systemic diseases. We developed a new method in which an eschar thinning operation was first adopted, followed by raising granulation tissue and microskin autografting, which was covered by a Vaseline-based moisture dressing. A total of 52 patients were included in this study and randomly assigned to the control group (n=26) and the experimental group (n=26) for the conventional method and the new method, respectively. The re-epithelisation rate on the 21st day after autografting indicated that there was no significant difference between both groups. There was also no significant difference between the two groups when the re-epithelialisation rate was compared with the type of organisms cultured. However, the Vancouver Burn Skin Score (VBSS) results demonstrated a significant improvement of cosmetic appearance in the experimental group (score=2.1) as compared to the control group (score=3.9). The new method also showed other advantages, including less blood loss, shorter surgical duration and lower cost of surgery. From this prospective study, it can be concluded that the new method can be an alternative to the conventional microskin autografting procedure.
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Construction of tissue-engineered cornea composed of amniotic epithelial cells and acellular porcine cornea for treating corneal alkali burn.
Biomaterials
PUBLISHED: 05-11-2013
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Although acellular corneas have been reported to be a potential substitute for allogeneic cornea transplantation to treat corneal injury, severe corneal injury is hard to repair due to inflammation and neovascularization. The use of the amniotic membrane as a graft in ocular surface reconstruction has become widespread because of the anti-inflammatory and anti-angiogenic properties of amniotic epithelial cells (AECs). Our objective was to construct a tissue-engineered cornea (TEC) composed of an acellular porcine cornea (APC) and AECs to repair severe corneal injury. Corneal cells were completely removed from the prepared APC, and the microstructure, mechanical properties, and stability of a natural porcine cornea (NPC) was maintained. In vitro, MTT and flow cytometry analyses showed that the APC did not negatively affect cell viability and apoptosis. In vivo, corneal pocket and subcutaneous transplantation demonstrated that the APC was incapable of trigging accepted immune response. AECs isolated from the human amniotic membrane have proliferation potential and present healthy morphology before 6 passages. After 7 days of culture on the surface of the APC, the AECs were stratified into 5-6 layers. We found that the AECs reconstituted the basement membrane that had been disrupted by the decellularization process. ELISA results showed that after culturing the TEC, the culture medium contained anti-inflammatory and anti-angiogenic growth factors, such as MIF, IL6, Fas-L, and PDEF. Finally, the results of lamellar keratoplasty to treat an alkali burn showed that the transplanted TEC was transparent and completely inoculated into the host cornea. However, the transplanted APC was degraded due to host rejection. Therefore, we conclude that a TEC composed of AECs and an APC holds great potential for the repair of severe corneal injury.
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Pharmacokinetics study of hemin in rats by applying (58)Fe-extrinsically labeling techniques in combination with ICP-MS method.
J Pharm Biomed Anal
PUBLISHED: 05-09-2013
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Iron is a challenging element due to its high background in various matrixes including blood, tissues even in the air and it is urgent to develop a method for the accurate determination of iron in bio-samples. After optimization of mass spectrometric conditions using collision cell technology and compensating for interference using a mathematical correction equation, an inductively coupled plasma mass spectrometry (ICP-MS) method for the quantitative determination of (58)Fe originating from hemin extrinsically labeled avoiding endogenous interference was developed. After a single step of dilution, analysis of each sample was completed within 1.5min. The assay was linear in the concentration range from 0.005 to 1.0?g/ml. The precisions and accuracies determined within three consecutive days were in acceptable limits and there was no significant matrix effect. The optimized method was successfully applied to a pharmacokinetic study of (58)Fe originating from hemin extrinsically labeled and iron absorption measured in rats was 1.07%. Those indicated that extrinsically label techniques in combination with ICP-MS will become a new tool for the analysis of iron preparations and other endogenous substances.
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An overview of the roles and responsibilities of Chinese medical colleges in body donation programs.
Anat Sci Educ
PUBLISHED: 04-14-2013
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The use of human tissue is critical for gross anatomy education in the health professions. Chinese medical colleges have faced a shortage of anatomical specimens over the past decade. While body donation plays an important role in overcoming this gap, this practice has only recently been introduced in China, and the donation rate is relatively low and fraught with a number of difficulties. In the past, traditional Chinese culture focused on preserving the human body intact, which often limited body donation. In recent years, the public has become more open toward body donation. At Nanjing Medical University, only 20 bodies were donated in 2001. After the university became involved in an organized body donation program, this number increased to 70 donated bodies per year (2007 to 2012). This article describes and reviews Chinese medical colleges as a special case study among body donation programs, particularly in terms of the multiple responsibilities and roles that such institutions must assume in the course of adopting these programs. Medical colleges in China must serve as advocates, coordinators, builders, managers, educators, and beneficiaries in undertaking body donation programs. It is important for medical colleges to recognize these pluripotent roles and educate the public in order to promote body donation programs. This case study may also effectively guide and encourage Chinese medical colleges in refining their own body donation programs in the future. Anat Sci Educ. © 2013 American Association of Anatomists.
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Molecular and subcellular-scale modeling of nucleotide diffusion in the cardiac myofilament lattice.
Biophys. J.
PUBLISHED: 02-26-2013
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Contractile function of cardiac cells is driven by the sliding displacement of myofilaments powered by the cycling myosin crossbridges. Critical to this process is the availability of ATP, which myosin hydrolyzes during the cross-bridge cycle. The diffusion of adenine nucleotides through the myofilament lattice has been shown to be anisotropic, with slower radial diffusion perpendicular to the filament axis relative to parallel, and is attributed to the periodic hexagonal arrangement of the thin (actin) and thick (myosin) filaments. We investigated whether atomistic-resolution details of myofilament proteins can refine coarse-grain estimates of diffusional anisotropy for adenine nucleotides in the cardiac myofibril, using homogenization theory and atomistic thin filament models from the Protein Data Bank. Our results demonstrate considerable anisotropy in ATP and ADP diffusion constants that is consistent with experimental measurements and dependent on lattice spacing and myofilament overlap. A reaction-diffusion model of the half-sarcomere further suggests that diffusional anisotropy may lead to modest adenine nucleotide gradients in the myoplasm under physiological conditions.
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A three-dimensional finite element model of human atrial anatomy: new methods for cubic Hermite meshes with extraordinary vertices.
Med Image Anal
PUBLISHED: 02-24-2013
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High-order cubic Hermite finite elements have been valuable in modeling cardiac geometry, fiber orientations, biomechanics, and electrophysiology, but their use in solving three-dimensional problems has been limited to ventricular models with simple topologies. Here, we utilized a subdivision surface scheme and derived a generalization of the "local-to-global" derivative mapping scheme of cubic Hermite finite elements to construct bicubic and tricubic Hermite models of the human atria with extraordinary vertices from computed tomography images of a patient with atrial fibrillation. To an accuracy of 0.6 mm, we were able to capture the left atrial geometry with only 142 bicubic Hermite finite elements, and the right atrial geometry with only 90. The left and right atrial bicubic Hermite meshes were G1 continuous everywhere except in the one-neighborhood of extraordinary vertices, where the mean dot products of normals at adjacent elements were 0.928 and 0.925. We also constructed two biatrial tricubic Hermite models and defined fiber orientation fields in agreement with diagrammatic data from the literature using only 42 angle parameters. The meshes all have good quality metrics, uniform element sizes, and elements with aspect ratios near unity, and are shared with the public. These new methods will allow for more compact and efficient patient-specific models of human atrial and whole heart physiology.
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GSK3? is a checkpoint for TNF-?-mediated impaired osteogenic differentiation of mesenchymal stem cells in inflammatory microenvironments.
Biochim. Biophys. Acta
PUBLISHED: 02-12-2013
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The fate and differentiation of mesenchymal stem cells (MSCs) depend on various microenvironmental cues. In chronic inflammatory bone disease, bone regeneration is inhibited. The present study therefore sought to identify the underlying molecule mechanisms.
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Effects of dietary factors on the pharmacokinetics of 58Fe-labeled hemin after oral administration in normal rats and the iron-deficient rats.
Biol Trace Elem Res
PUBLISHED: 01-14-2013
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Hemin, iron (III) protoporphyrin chloride (IX), as a stable form of heme iron, has been used in iron absorption studies. The aim of the present study was to elucidate the influences of body iron status and three dietary factors (green tea extract, ascorbic acid, and calcium) on the pharmacokinetics of hemin using stable isotope labeling methods followed by ICP-MS measurement. In this study, a rapid, sensitive, and specific ICP-MS method for the determination of (58)Fe originating from hemin in rat plasma was developed and a rat model of iron deficiency anemia was established. It was found that hemin iron absorption increased significantly under iron deficiency anemia status, with AUC0-t and AUC0-? showing significant increase in anemic rats compared to normal ones. Green tea extract strongly inhibited hemin iron absorption in both normal rats and iron-deficient rats. In normal rats administered with green tea extract, C max resulted significantly reduced, whereas in anemic rats administered with green tea extract both AUC0-t and AUC0-? were reduced. On the other hand, ascorbic acid significantly affected hemin iron absorption only in iron-deficient rats, in which C max showed a significant increase. Interestingly, calcium slowed down the hemin iron absorption rate in normal rats, MRT0-t being significantly different in calcium-treated animals compared to untreated ones. This trend also appeared in the iron-deficient group but it did not reach statistical significance. Our data suggest that the mechanism of hemin iron absorption is regulated by body iron status and dietary factors can influence hemin iron absorption to varying degrees. Moreover, these results may also have general implication in the iron deficiency treatment with iron supplements and fortification of foods.
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Genetic diversity and population structure of rice pathogen Ustilaginoidea virens in China.
PLoS ONE
PUBLISHED: 01-01-2013
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Rice false smut caused by the fungal pathogen Ustilaginoidea virens is becoming a destructive disease throughout major rice-growing countries. Information about its genetic diversity and population structure is essential for rice breeding and efficient control of the disease. This study compared the genome sequences of two U. virens isolates. Three SNP-rich genomic regions were identified as molecular markers that could be used to analyze the genetic diversity and population structure of U. virens in China. A total of 56 multilocus sequence types (haplotypes) were identified out of 162 representative isolates from 15 provinces covering five major rice-growing areas in China. However, the phylogeny, based on sequences at individual SNP-rich regions, strongly conflicted with each other and there were significant genetic differences between different geographical populations. Gene flow between the different geographical populations and genetic differentiation within each geographical population were also detected. In addition, genetic recombination and genetic isolation resulting from geographic separation was also found.
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An efficient direction field-based method for the detection of fasteners on high-speed railways.
Sensors (Basel)
PUBLISHED: 06-28-2011
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Railway inspection is an important task in railway maintenance to ensure safety. The fastener is a major part of the railway which fastens the tracks to the ground. The current article presents an efficient method to detect fasteners on the basis of image processing and pattern recognition techniques, which can be used to detect the absence of fasteners on the corresponding track in high-speed(up to 400 km/h). The Direction Field is extracted as the feature descriptor for recognition. In addition, the appropriate weight coefficient matrix is presented for robust and rapid matching in a complex environment. Experimental results are presented to show that the proposed method is computation efficient and robust for the detection of fasteners in a complex environment. Through the practical device fixed on the track inspection train, enough fastener samples are obtained, and the feasibility of the method is verified at 400 km/h.
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Effect of heparin following cervical spinal cord injuries in rats.
Neurosurgery
PUBLISHED: 05-26-2011
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Risks of neurological deterioration after heparin administration following cervical spinal cord injury (SCI) in humans are unknown.
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Design and analysis of a differential waveguide structure to improve magnetostrictive linear position sensors.
Sensors (Basel)
PUBLISHED: 03-18-2011
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Magnetostrictive linear position sensors (MLPS) are high-precision sensors used in the industrial field for measuring the propagation time of ultrasonic signals in a waveguide. To date, MLPS have attracted widespread attention for their accuracy, reliability, and cost-efficiency in performing non-contact, multiple measurements. However, the sensor, with its traditional structure, is susceptible to electromagnetic interference, which affects accuracy. In the present study, we propose a novel structure of MLPS that relies on two differential waveguides to improve the signal-to-noise ratio, common-mode rejection ratio, and accuracy of MLPS. The proposed sensor model can depict sensor performance and the relationship of sensor parameters. Experimental results with the new sensor indicate that the new structure can improve accuracy to ±0.1 mm higher than ±0.2 mm with a traditional structure. In addition, the proposed sensor shows a considerable improvement in temperature characteristics.
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Purification and characterization of a novel immunomodulatory protein from the medicinal mushroom Trametes versicolor.
Sci China Life Sci
PUBLISHED: 03-04-2011
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Bioactive proteins represent an important group of functional agents in medicinal mushrooms. Trametes versicolor (L.) Lloyd is a mushroom frequently used in traditional Chinese medicine for its anti-tumor and immunomodulatory activities. A new immunomodulatory protein from T. versicolor, named TVC, was purified by ammonium sulfate precipitation, ion-exchange chromatography and gel filtration chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of the purified protein revealed a single band with a molecular weight of 15.0 kD. Native polyacrylamide gel analysis revealed a band at 30 kD, indicating that TVC exists in solution as a homodimer. Isoelectric focusing showed that TVC was an acidic protein with an isoelectric point of 4.0. TVC was found to lack carbohydrate modifications (based on periodic acid/Schiff staining) and it does not agglutinate mouse red blood cells, suggesting that TVC is not a lectin-like protein. Biological activity assays demonstrated that TVC can enhance the proliferation of splenocytes, while it has no stimulatory effects on CD4(+) and CD8(+) T cells. TVC markedly increases the proliferation of human peripheral blood lymphocytes in a dose-dependent manner and enhances the production of both nitric oxide and tumor necrosis factor-alpha by lipopolysaccharide-induced murine macrophages. The results indicate that TVC is an immunostimulant that can boost immune response. Comparison of the N-terminal amino acid residues and mass spectrometry results with the protein database revealed no homologous proteins.
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Mixture of fibroblasts and adipose tissue-derived stem cells can improve epidermal morphogenesis of tissue-engineered skin.
Cells Tissues Organs (Print)
PUBLISHED: 01-27-2011
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Many studies demonstrate that the type of adjacent mesenchymal cells can affect epidermal morphogenesis of bilayered tissue-engineered skin. However, whether a mixture of different mesenchymal cell types can improve epidermal morphogenesis of bioengineered skin remains unknown. In this study, keratinocytes, dermal fibroblasts and adipose tissue-derived stem cells (ADSCs) were isolated and purified from human skin and subcutaneous fat. Conditioned medium generated from a mixture of dermal fibroblasts and ADSCs at the ratio of 1:1 was superior to that from fibroblasts or ADSCs alone in promoting keratinocyte proliferation, as indicated by MTT assay. Furthermore, ELISA results showed that the cytokine levels of human hepatocyte growth factor and keratinocyte growth factor (also known as FGF7) in the mixed fibroblasts/ADSC group were higher than those in the ADSC or dermal fibroblasts group. To examine the potential roles of mixed fibroblasts and ADSCs on epidermal morphogenesis, a three-dimensional tissue engineered skin system was applied. Histological analyses demonstrated that keratinocytes proliferated extensively over the mixture of fibroblasts and ADSCs, and formed a thick epidermal layer with well-differentiated structures. Keratin 10 (epidermal differentiation marker) was expressed in the suprabasal layer of bilayered tissue-engineered skin in the mixed fibroblasts and ADSCs group. Desmosomes and hemidesmosomes were detected in the newly formed epidermis by transmission electron microscopy analysis. Together, these findings revealed for the first time that a mixture of fibroblasts and ADSCs in bilayered tissue-engineered skin can improve epidermal morphogenesis.
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Functional neovascularization in tissue engineering with porcine acellular dermal matrix and human umbilical vein endothelial cells.
Tissue Eng Part C Methods
PUBLISHED: 12-19-2010
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Endothelial cells-matrix interactions play an important role in promoting and controlling network formation. In this study, porcine acellular dermal matrix (PADM) was used to guide human umbilical vein endothelial cells (HUVECs) adhesion and proliferation as a potential system for vascularization of engineered tissues. We fabricated PADM using a modified protocol and assessed their composition and ultrastructures. Subsequently, the viability of HUVECs and the formation of capillary-like networks were evaluated by seeding cells directly on PADM scaffolds or PADM digests in vitro. We further investigated the function of the HUVECs seeded on the PADM scaffolds after subcutaneous transplantation in athymic mice. Moreover, the function of the neovessels formed in the PADM scaffolds was assessed by implantation into cutaneous wounds on the backs of mice. The results showed that PADM scaffolds significantly increased proliferation of HUVECs, and the PADM digest induced HUVECs formed many tube-like structures. Moreover, HUVECs seeded on the PADM scaffolds formed numerous capillary-like networks and some perfused vascular structures after implantation into mice. PADM seeded with HUVECs and fibroblasts were also able to form many capillary-like networks in vitro. Further, these neovessels could inosculate with the murine vasculature after implantation into cutaneous wounds in mice. The advantage of this method is that the decellularized matrix not only provides signals to maintain the viability of endothelial cells but also serves as the template structure for regenerated tissue. These findings indicate that PADM seeded with HUVECs may be a potential system for successful engineering of large, thick, and complex tissues.
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Synergistic angiogenesis promoting effects of extracellular matrix scaffolds and adipose-derived stem cells during wound repair.
Tissue Eng Part A
PUBLISHED: 12-18-2010
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Slow vascularization rate is considered one of the main drawbacks of scaffolds used in wound healing. Several efforts, including cellular and acellular technologies, have been made to induce vascular growth in scaffolds. However, thus far, there is no established technology for inducing vascular growth. The aim of this study was to promote the vascularization capacities of scaffolds by seeding adipose-derived stem cells (ADSCs) on them and to compare the vascularization capacities of different scaffolds seeded with ADSCs. Two kinds of extracellular matrix scaffolds (small intestinal submucosa [SIS] and acellular dermal matrix [ADM]) and a kind of composite scaffold (collagen-chondroitin sulfate-hyaluronic acid [Co-CS-HA]) were selected. Subcutaneous implantation analysis showed that the vascularization capacity of SIS and ADM was greater than that of Co-CS-HA. ADSCs seeded in SIS and ADM secreted greater amounts of vascular endothelial growth factor than those seeded in Co-CS-HA. In a murine skin injury model, ADSC-seeded scaffolds enhanced the angiogenesis and wound healing rate compared with the nonseeded scaffolds. Moreover, ADSC-SIS and ADSC-ADM had greater vascularization capacity than that of ADSC-Co-CS-HA. Taken together, these results suggest that ADSCs could be used as a cell source to promote the vascularization capacities of scaffolds. The vascularization capacities of ADSC-seeded scaffolds were influenced by both the vascularization capacities of the scaffolds themselves and their effects on the angiogenic potential of ADSCs; the combination of extracellular matrix scaffolds and ADSCs exhibited synergistic angiogenesis promoting effects.
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High diversity of the fungal community structure in naturally-occurring Ophiocordyceps sinensis.
PLoS ONE
PUBLISHED: 08-07-2010
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Ophiocordyceps sinensis (syn. Cordyceps sinensis), which is a parasite of caterpillars and is endemic to alpine regions on the Tibetan Plateau, is one of the most valuable medicinal fungi in the world. "Natural O. sinensis specimens" harbor various other fungi. Several of these other fungi that have been isolated from natural O. sinensis specimens have similar chemical components and/or pharmaceutical effects as O. sinensis. Nevertheless, the mycobiota of natural O. sinensis specimens has not been investigated in detail.
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Enhanced adenoviral gene delivery to motor and dorsal root ganglion neurons following injection into demyelinated peripheral nerves.
J. Neurosci. Res.
PUBLISHED: 07-13-2010
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Injection of viral vectors into peripheral nerves may transfer specific genes into their dorsal root ganglion (DRG) neurons and motoneurons. However, myelin sheaths of peripheral axons block the entry of viral particles into nerves. We studied whether mild, transient peripheral nerve demyelination prior to intraneural viral vector injection would enhance gene transfer to target DRG neurons and motoneurons. The right sciatic nerve of C57BL/6 mice was focally demyelinated with 1% lysolecithin, and the left sciatic nerve was similarly injected with saline (control). Five days after demyelination, 0.5 microl of Ad5-GFP was injected into both sciatic nerves at the site of previous injection. The effectiveness of gene transfer was evaluated by counting GFP(+) neurons in the DRGs and ventral horns. After peripheral nerve demyelination, there was a fivefold increase in the number of infected DRG neurons and almost a 15-fold increase in the number of infected motoneurons compared with the control, nondemyelinated side. Focal demyelination reduced the myelin sheath barrier, allowing greater virus-axon contact. Increased CXADR expression on the demyelinated axons facilitated axoplasmic viral entry. No animals sustained any prolonged neurological deficits. Increased gene delivery into DRG neurons and motoneurons may provide effective treatment for amyotrophic lateral sclerosis, pain, and spinal cord injury.
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Overexpression of ATA1/SLC38A1 predicts future recurrence and death in Chinese patients with hilar cholangiocarcinoma.
J. Surg. Res.
PUBLISHED: 03-12-2010
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System A amino acid transporter is a Na+-dependent active transport system, mediating the uptake of amino acids, dysregulation of which has been found to be associated with malignant transformation in mammalian cells. However, the role of ATA1 in hilar cholangiocarcinoma is unclear. Here, we investigated ATA1 expression and determined its clinical significance in hilar cholangiocarcinoma. Tissue microarray blocks containing tumor specimens obtained from 48 patients were constructed. Expression of ATA1 in these specimens was analyzed using immunohistochemical studies. ATA1 overexpression was observed in 22 cases (44.9%). Overexpression of ATA1 was significantly associated with lymph node metastases. ATA1 expression has a significant correlation with recurrence and poor survival in univariate analyses. Multivariate analyses revealed that ATA1 was an independent predictor for future recurrence in patients with cholangiocarcinoma. Increased expression of ATA1 is frequent in human hilar cholangiocarcinoma and significantly correlated with the progression of cholangiocarcinoma, suggesting the importance of ATA1 in cancer development and progression. ATA1 expression may be used to predict recurrence and death and can serve as a promising target for therapy of this malignancy.
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A nerve graft constructed with xenogeneic acellular nerve matrix and autologous adipose-derived mesenchymal stem cells.
Biomaterials
PUBLISHED: 03-08-2010
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Since synthetic nerve conduits do not exhibit the characteristics of regeneration, they are generally inadequate substitutes for autologous nerve graft in the repair of long peripheral nerve defects. To resolve this problem, in this study, we constructed a nerve regeneration characteristics-containing nerve graft through integrating xenogeneic acellular nerve matrix (ANM) with autologous neural differentiated adipose-derived mesenchymal stem cells (ADSCs). Xenogeneic ANM was processed by a protocol removing cells and myelin sheath completely, meanwhile preserving growth factors and extracellular matrix (ECM) microstructure of natural nerve, such as porous and basal lamina tube. Cytocompatibility and immunocompatibility evaluation revealed that ANM could support cell attachment and proliferation, and did not stimulate vigorous host reject response. After inoculation of neural differentiated ADSCs onto ANM, differentiated cells were observed to align along longitudinal axis of ANM, resembling band of büngner, and persistently express NGF, GDNF, and BDNF. In vivo, neural differentiated ADSCs also presented glial cell characteristics and promote nerve regeneration 7 days post transplantation. We repaired 1cm Sprague Dawley rat sciatic nerve defects using this nerve graft construction and nerve gap regeneration was indicated by electrophysiology, retrograde labeling and histology analysis. Therefore, we conclude that constructed nerve graft, offering nerve regeneration characteristics, hold great promise to replace autologous in repair peripheral nerve defect.
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An Automatic 3D Mesh Generation Method for Domains with Multiple Materials.
Comput Methods Appl Mech Eng
PUBLISHED: 02-18-2010
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This paper describes an automatic and efficient approach to construct unstructured tetrahedral and hexahedral meshes for a composite domain made up of heterogeneous materials. The boundaries of these material regions form non-manifold surfaces. In earlier papers, we developed an octree-based isocontouring method to construct unstructured 3D meshes for a single-material (homogeneous) domain with manifold boundary. In this paper, we introduce the notion of a material change edge and use it to identify the interface between two or several different materials. A novel method to calculate the minimizer point for a cell shared by more than two materials is provided, which forms a non-manifold node on the boundary. We then mesh all the material regions simultaneously and automatically while conforming to their boundaries directly from volumetric data. Both material change edges and interior edges are analyzed to construct tetrahedral meshes, and interior grid points are analyzed for proper hexahedral mesh construction. Finally, edge-contraction and smoothing methods are used to improve the quality of tetrahedral meshes, and a combination of pillowing, geometric flow and optimization techniques is used for hexahedral mesh quality improvement. The shrink set of pillowing schemes is defined automatically as the boundary of each material region. Several application results of our multi-material mesh generation method are also provided.
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Establishment of three-dimensional tissue-engineered bone constructs under microgravity-simulated conditions.
Artif Organs
PUBLISHED: 10-10-2009
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Bone constructs have been grown in vitro with use of isolated cells, biodegradable polymer scaffolds, and bioreactors. In our work, the relationships between the composition and mechanical properties of engineered bone constructs were studied by culturing bone marrow mesenchymal stem cells (BMSCs) on ceramic bovine bone scaffolds in different environments: static flasks and dynamic culture system in rotating vessels-which was a National Aeronautics and Space Administration-recommended, ground-based, microgravity-simulating system. After 15 days of cultivation, osteogenicity was determined according to DNA and alkaline phosphatase (ALP) analysis. DNA content and ALP were higher for cells grown on dynamic culture. Subsequently, the two kinds of engineered bone constructs were selected for transplantation into Sprague-Dawley rat cranial bone defects. After 24 weeks of in vivo implantation, the engineered bone constructs under dynamic culture were found to repair the defects better, with the engineered constructs showing histologically better bone connection. Thus, this dynamic system provides a useful in vitro model to construct the functional role and effects of osteogenesis in the proliferation, differentiation, and maturation of BMSCs. These findings suggest that the hydrodynamic microgravity conditions in tissue-culture bioreactors can modulate the composition, morphology, and function of the engineered bone.
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[Bilateral effects of the pre- and postoperative septoplasty evaluated objectively with acoustic rhinometry and rhinomanometry].
Lin Chung Er Bi Yan Hou Tou Jing Wai Ke Za Zhi
PUBLISHED: 09-24-2009
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To evaluate effects of septoplasty on bilateral nasal cavities with acoustic rhinometry and rhinomanometry objectively.
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Promotion of central nervous system remyelination by induced differentiation of oligodendrocyte precursor cells.
Ann. Neurol.
PUBLISHED: 04-01-2009
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Repair of demyelinated axons in diseases such as multiple sclerosis requires activation of the myelination program in existing or newly recruited oligodendrocyte precursor cells (OPCs). The control of OPC differentiation and initiation of myelination during repair is poorly understood. In this study, we test the ability of anti-LINGO-1 reagents to promote myelination in vitro and remyelination in the rodent adult central nervous system in vivo.
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Genetic diversity of Ophiocordyceps sinensis, a medicinal fungus endemic to the Tibetan Plateau: implications for its evolution and conservation.
BMC Evol. Biol.
PUBLISHED: 03-15-2009
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Ophiocordyceps sinensis (syn. Cordyceps sinensis), endemic to alpine regions on the Tibetan plateau, is one of the most valuable medicinal fungi in the world. Huge commercial demand has led to excessive harvest and a dramatic decline in its numbers. The diversity of terrains and climates on the Tibetan Plateau and the broad insect host range (more than 50 species in the family Hepialidae) may have resulted in substantial intraspecific genetic diversity for this fungus. The objective of this study was to evaluate the population distribution of O. sinensis from geographically diverse regions of the Tibetan Plateau based on nrDNA ITS and MAT1-2-1 gene sequences. Understanding of the genetic diversity and genesis of O. sinensis will provide important information for the evolution and conservation of this fungus.
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Functional bilayered skin substitute constructed by tissue-engineered extracellular matrix and microsphere-incorporated gelatin hydrogel for wound repair.
Tissue Eng Part A
PUBLISHED: 02-10-2009
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Our aim in this study was to develop a new methodology for constructing a bilayer skin equivalent to create a clinically compliant skin graft composite for the treatment of various skin defects. We utilized tissue-engineered extracellular matrix (TEECM) that maintains the native dermal components, as analogical dermal layer, and gelatin hydrogel containing epidermal growth factor (EGF)-loaded microspheres, as epidermis layer upon TEECM. The bilayer skin equivalent (GG-EGF/TEECM) could be synthesized appropriately and has been hypothesized to provide an enhanced effect on re-epithelization, apart from dermal reconstruction improved by TEECM. Morphological properties, EGF release efficiency, cytotoxicity, and effects on wound repair of this composite were investigated in this study. It was shown that the two layers adhered firmly to each other, and the percentage of cumulative release was approximately 80% by day 14. Moreover, as a biocompatible equivalent, GG-EGF/TEECM improved the healing of the wound area as indicated by significantly earlier re-epithelialization and dermal maturation. These results suggest that GG-EGF/TEECM can provide an optimal microenvironment and proper template for skin tissue engineering.
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Anatomical and functional outcomes following a precise, graded, dorsal laceration spinal cord injury in C57BL/6 mice.
J. Neurotrauma
PUBLISHED: 02-07-2009
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To study the pathophysiology of spinal cord injury (SCI), we used the LISA-Vibraknife to generate a precise and reproducible dorsal laceration SCI in the mouse. The surgical procedure involved a T9 laminectomy, dural resection, and a spinal cord laceration to a precisely controlled depth. Four dorsal hemisection injuries with lesion depths of 0.5, 0.8, 1.1, and 1.4 mm, as well as normal, sham (laminectomy and dural removal only), and transection controls were examined. Assessments including the Basso Mouse Scale (BMS), footprint analysis, beam walk, toe spread reflex, Hargreaves test, and transcranial magnetic motor-evoked potential (tcMMEP) analysis were performed to assess motor, sensorimotor, and sensory function. These outcome measures demonstrated significant increases in functional deficits as the depth of the lesion increased, and significant behavioral recovery was observed in the groups over time. Quantitative histological examination showed significant differences between the injury groups and insignificant lesion depth variance within each of the groups. Statistically significant differences were additionally found in the amount of ventral spared tissue at the lesion site between the injury groups. This novel, graded, reproducible laceration SCI model can be used in future studies to look more closely at underlying mechanisms that lead to functional deficits following SCI, as well as to determine the efficacy of therapeutic intervention strategies in the injury and recovery processes following SCI.
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Expansion and delivery of human fibroblasts on micronized acellular dermal matrix for skin regeneration.
Biomaterials
PUBLISHED: 01-08-2009
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In order to obtain an abundant supply of autologous dermal fibroblasts for the manufacture of engineered autologous dermal substitutes, we fabricated the micronized acellular dermal matrix (MADM) microcarriers and expanded human fibroblasts on them. This novel approach eliminated the need for the repeated trypsinizations that may disrupt cell-extracellular matrix interactions and impair cell viability. This cell expansion protocol simultaneously formed an engineered particulate dermal substitute (EPDS) avoiding cell reseeded on the scaffolds process. We further tested its feasibility and effectiveness in athymic murine subcutaneous injection and full-thickness cutaneous wound model. Our results showed that MADM microcarriers retained the ultrastructure of the acellular dermal matrix, had good biocompatibility, and supported human fibroblast expansion either as a direct culture substrate or through culturing cells in conditioned medium prepared from them. In the animal study, EPDS formed a thick layer of tissue below the subcutaneous muscle tissue at 3 weeks following EPDS injection into subcutaneous tissue. In full-thickness cutaneous wound, the degree of wound healing with EPDS implantation was better than that without EPDS although healing rates were not significantly different between wounds implanted with or without EPDS. This demonstrates the potential utility of MADM not only as a cell culture substrate to expand fibroblasts but also as a cell transplantation vehicle for skin regeneration, with several advantages over current expansion-transplantation protocols for skin regeneration. In addition, EPDS may be used for cosmetic or reconstructive soft tissue augmentation in a minimally invasive fashion.
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Dynamic lung modeling and tumor tracking using deformable image registration and geometric smoothing.
Mol Cell Biomech
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A greyscale-based fully automatic deformable image registration algorithm, based on an optical flow method together with geometric smoothing, is developed for dynamic lung modeling and tumor tracking. In our computational processing pipeline, the input data is a set of 4D CT images with 10 phases. The triangle mesh of the lung model is directly extracted from the more stable exhale phase (Phase 5). In addition, we represent the lung surface model in 3D volumetric format by applying a signed distance function and then generate tetrahedral meshes. Our registration algorithm works for both triangle and tetrahedral meshes. In CT images, the intensity value reflects the local tissue density. For each grid point, we calculate the displacement from the static image (phase 5) to match with the moving image (other phases) by using merely intensity values of the CT images. The optical flow computation is followed by a regularization of the deformation field using geometric smoothing. Lung volume change and the maximum lung tissue movement are used to evaluate the accuracy of the application. Our testing results suggest that the application of deformable registration algorithm is an effective way for delineating and tracking tumor motion in image-guided radiotherapy.
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In silico vascular modeling for personalized nanoparticle delivery.
Nanomedicine (Lond)
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To predict the deposition of nanoparticles in a patient-specific arterial tree as a function of the vascular architecture, flow conditions, receptor surface density and nanoparticle properties.
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Surface curvature as a classifier of abdominal aortic aneurysms: a comparative analysis.
Ann Biomed Eng
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An abdominal aortic aneurysm (AAA) carries one of the highest mortality rates among vascular diseases when it ruptures. To predict the role of surface curvature in rupture risk assessment, a discriminatory analysis of aneurysm geometry characterization was conducted. Data was obtained from 205 patient-specific computed tomography image sets corresponding to three AAA population subgroups: patients under surveillance, those that underwent elective repair of the aneurysm, and those with an emergent repair. Each AAA was reconstructed and their surface curvatures estimated using the biquintic Hermite finite element method. Local surface curvatures were processed into ten global curvature indices. Statistical analysis of the data revealed that the L2-norm of the Gaussian and Mean surface curvatures can be utilized as classifiers of the three AAA population subgroups. The application of statistical machine learning on the curvature features yielded 85.5% accuracy in classifying electively and emergent repaired AAAs, compared to a 68.9% accuracy obtained by using maximum aneurysm diameter alone. Such combination of non-invasive geometric quantification and statistical machine learning methods can be used in a clinical setting to assess the risk of rupture of aneurysms during regular patient follow-ups.
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Experimental estimating deflection of a simple beam bridge model using grating eddy current sensors.
Sensors (Basel)
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A novel three-point method using a grating eddy current absolute position sensor (GECS) for bridge deflection estimation is proposed in this paper. Real spatial positions of the measuring points along the span axis are directly used as relative reference points of each other rather than using any other auxiliary static reference points for measuring devices in a conventional method. Every three adjacent measuring points are defined as a measuring unit and a straight connecting bar with a GECS fixed on the center section of it links the two endpoints. In each measuring unit, the displacement of the mid-measuring point relative to the connecting bar measured by the GECS is defined as the relative deflection. Absolute deflections of each measuring point can be calculated from the relative deflections of all the measuring units directly without any correcting approaches. Principles of the three-point method and displacement measurement of the GECS are introduced in detail. Both static and dynamic experiments have been carried out on a simple beam bridge model, which demonstrate that the three-point deflection estimation method using the GECS is effective and offers a reliable way for bridge deflection estimation, especially for long-term monitoring.
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Absence of PTHrP nuclear localization and carboxyl terminus sequences leads to abnormal brain development and function.
PLoS ONE
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We assessed whether the nuclear localization sequences (NLS) and C terminus of parathyroid hormone-related protein (PTHrP) play critical roles in brain development and function. We used histology, immunohistochemistry, histomorphometry, Western blots and electrophysiological recordings to compare the proliferation and differentiation of neural stem cells, neuronal hippocampal synaptic transmission, and brain phenotypes including shape and structures, in Pthrp knock-in mice, which express PTHrP (1-84), a truncated form of the protein that is missing the NLS and the C-terminal region of the protein, and their wild-type littermates. Results showed that Pthrp knock-in mice display abnormal brain shape and structures; decreased neural cell proliferative capacity and increased apoptosis associated with up-regulation of cyclin dependent kinase inhibitors p16, p21, p27 and p53 and down-regulation of the Bmi-1 oncogene; delayed neural cell differentiation; and impaired hippocampal synaptic transmission and plasticity. These findings provide in vivo experimental evidence that the NLS and C-terminus of PTHrP are essential not only for the regulation of neural cell proliferation and differentiation, but also for the maintenance of normal neuronal synaptic transmission and plasticity.
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An atlas-based geometry pipeline for cardiac Hermite model construction and diffusion tensor reorientation.
Med Image Anal
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Here we present a novel atlas-based geometry pipeline for constructing three-dimensional cubic Hermite finite element meshes of the whole human heart from tomographic patient image data. To build the cardiac atlas, two superior atria, two inferior ventricles as well as the aorta and the pulmonary trunk are first segmented, and epicardial and endocardial boundary surfaces are extracted and smoothed. Critical points and skeletons (or central-line paths) are identified, following the cardiac topology. The surface model and the path tree are used to construct a hexahedral control mesh via a skeleton-based sweeping method. Derivative parameters are computed from the control mesh, defining cubic Hermite finite elements. The thickness of the atria and the ventricles is obtained using segmented epicardial boundaries or via offsetting from the endocardial surfaces in regions where the image resolution is insufficient. We also develop a robust optical flow approach to deform the constructed atlas and align it with the image from a second patient. This registration method is fully-automatic, and avoids manual operations required by segmentation and path extraction. Moreover, we demonstrate that this method can also be used to deformably map diffusion tensor MRI data with patient geometries to include fiber and sheet orientations in the finite element model.
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Design of compensation coils for EMI suppression in magnetostrictive linear position sensors.
Sensors (Basel)
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This paper presents recent development on magnetostrictive linear position sensors (MLPS). A new compensation coil structure improves the EMI suppression and accuracy considerably. Furthermore, experimental results indicate that the new structure can improve the accuracy to ± 0.13 mm nearly double the ± 0.2 mm obtained with traditional structures. As another design continuation after the differential waveguide structure, this new structure is a practical and reliable implementation technique for the commercialization of MLPS.
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Neuronal sensitivity to TDP-43 overexpression is dependent on timing of induction.
Acta Neuropathol.
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Ubiquitin-immunoreactive neuronal inclusions composed of TAR DNA binding protein of 43 kDa (TDP-43) are a major pathological feature of frontotemporal lobar degeneration (FTLD-TDP). In vivo studies with TDP-43 knockout mice have suggested that TDP-43 plays a critical, although undefined role in development. In the current report, we generated transgenic mice that conditionally express wild-type human TDP-43 (hTDP-43) in the forebrain and established a paradigm to examine the sensitivity of neurons to TDP-43 overexpression at different developmental stages. Continuous TDP-43 expression during early neuronal development produced a complex phenotype, including aggregation of phospho-TDP-43, increased ubiquitin immunoreactivity, mitochondrial abnormalities, neurodegeneration and early lethality. In contrast, later induction of hTDP-43 in the forebrain of weaned mice prevented early death and mitochondrial abnormalities while yielding salient features of FTLD-TDP, including progressive neurodegeneration and ubiquitinated, phospho-TDP-43 neuronal cytoplasmic inclusions. These results suggest that neurons in the developing forebrain are extremely sensitive to TDP-43 overexpression and that timing of TDP-43 overexpression in transgenic mice must be considered when distinguishing normal roles of TDP-43, particularly as they relate to development, from its pathogenic role in FTLD-TDP and other TDP-43 proteinopathies. Finally, our adult induction of hTDP-43 strategy provides a mouse model that develops critical pathological features that are directly relevant for human TDP-43 proteinopathies.
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Inhibition of LDH-A by lentivirus-mediated small interfering RNA suppresses intestinal-type gastric cancer tumorigenicity through the downregulation of Oct4.
Cancer Lett.
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Many tumors metabolise the majority of the glucose that they take up through glycolysis even in the presence of an adequate oxygen supply. Lactate dehydrogenase A (LDH-A) is the critical enzyme that catalyses the transformation of pyruvate to lactate. We demonstrate that LDH-A reduction can suppress the tumorigenicity of intestinal-type gastric cancer (ITGC) cells by downregulating Oct4 both in vitro and in vivo. A statistical analysis of 661 ITGC specimens showed a significant correlation between LDH-A and Oct4 expression. Moreover, patients with low LDH-A/negative Oct4 expression exhibited better overall survival than patients with other combinations. We conclude that the close correlation of LDH-A and Oct4 may offer a promising therapeutic strategy for ITGC.
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The protection of MSCs from apoptosis in nerve regeneration by TGF?1 through reducing inflammation and promoting VEGF-dependent angiogenesis.
Biomaterials
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Our previous report demonstrated that autologous adipose-derived mesenchymal stem cells (ADSCs) combined with xenogeneic acellular nerve matrix (XANM) can support the regeneration of defective nerves. Although ADSCs had the potential to replace Schwann cells in engineered-tissue nerves, apoptosis easily obstructed the ability to treat serious nerve injury in the host, such as a >50-mm-long nerve defect. In the present study, we found that, in combination with transforming growth factor ?1 (TGF?1), an ADSCs-XANM graft was sufficient to support the regeneration of a 50-mm sciatic nerve defect, which was not achieved using an ADSCs-XANM graft alone. Based on this finding, we further investigated how TGF?1 coordinated with ADSCs to enhance nerve regeneration. In vitro, cell culture experiments demonstrated that TGF?1 did not have a direct effect on ADSC proliferation, apoptosis, the cell cycle, or neural differentiation. The expression of VEGF, however, was significantly increased in ADSCs cultured with TGF?1. In vivo, fluorescence labeling experiments demonstrated that the survival of transplanted ADSCs inoculated with XANM-TGF?1 was higher than with XANM. Further study showed that TGF?1 was capable of impairing the host immune response that was trigged by transplanted XANM. Additionally, we discovered that XANM-ADSCs in immunodeficient mice had apoptosis rates similar to XANM-ADSCs-TGF?1 over a short time course (7 days). Once we blocked VEGF with a neutralizing antibody, the protective effect of TGF?1 was impaired over a long time course (28 days). These results suggested that TGF?1 was capable of enhancing the regenerative capacity of an XANM-ADSCs graft, mainly by protecting transplanted ADSCs from apoptosis. This effect was achieved in part through decreasing inflammation and promoting VEGF-dependent angiogenesis.
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Pharmacokinetics, tissue distribution, and plasma protein binding study of platinum originating from dicycloplatin, a novel antitumor supramolecule, in rats and dogs by ICP-MS.
Biol Trace Elem Res
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Dicycloplatin, as a new antitumor supramolecule, was considered to have higher solubility and higher stability compared with carboplatin. The aim of the present study was to evaluate the pharmacokinetic characteristics of platinum originating from dicycloplatin. A rapid, sensitive, and specific method with inductively coupled plasma mass spectrometry (ICP-MS) has been developed for the determination of platinum in bio-samples. The study was performed in male rats and dogs at a single dose of 10 and 5 mg kg(-1) separately by intravenous injection. Pharmacokinetic parameters were calculated by non-compartmental method, and the dose of platinum was used in the calculation of these parameters. Results showed that plasma concentrations of platinum began to decrease rapidly initially but decline slowly with a long terminal phase. The mean half-life was 27.39 and 100.98 and clearance was 0.77 and 0.08 L/h/kg for rats and dogs separately. Tissue distribution showed that platinum originating from dicycloplatin had a certain distribution in testis and prostate. Plasma protein binding proportion of platinum was increased with time. In conclusion, this research investigated the pharmacokinetic characteristics including plasma kinetics, tissue distribution, and plasma protein binding of platinum originating from dicycloplatin in rats and dogs in detail for the first time by ICP-MS.
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Cervical central canal occlusion induces noncommunicating syringomyelia.
Neurosurgery
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Mechanisms underlying the development of noncommunicating syringomyelia are poorly understood.
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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.