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Biomedical subjects

Kai Wang

Publications and source records attributed to Kai Wang.

121 records · Page 7Linked to original sources
PubMed2003

[Hemorheologic changes in patients with liver diseases].

BACKGROUND: To study the variation of the hemorheology and microcirculation in different period of liver diseases. METHODS: Indices for hemorheology, liver function, HBV DNA and transfusion transmitted virus (TTV) DNA were measured in 82 patients with liver diseases and correlative analysis was made. RESULTS: The low-shear whole blood viscosity (BV) and RBC aggregation index were significantly higher in hepatitis B group than those in the control group (P less than 0.05). No correlation was found between HBV DNA and indices of hemorheology (P greater than 0.05). The high-shear and low-shear BV and hematocrit (HCT) were significantly lower in decompensated cirrhosis group than those in the control group (P less than 0.05). RBC aggregation index, plasma viscosity (PV) and the low-shear BV were significantly higher in compensated cirrhosis group than those in the control group (P less than 0.05). The high-shear and low-shear BV were significantly higher in TTV positive group than those in the control group. CONCLUSION: There is disturbance of microcirculation in the body of patients with hepatitis B or TTV infection. The blood of patients with compensated cirrhosis is in highly viscose status and in low viscose status in patients with decompensated cirrhosis. TTV seems to be harmful to some degree to the body. The hemorheology should be an index in detecting liver diseases in addition to HBV markers.

Adult↗
PubMed2002

Administration of recombinant P-selectin glycoprotein ligand Fc fusion protein suppresses inflammation and neointimal formation in Zucker diabetic rat model.

OBJECTIVE: P-selectin-mediated leukocyte-endothelium and leukocyte-platelet interaction has been reported after vascular injury and has been correlated with neointimal hyperplasia, but its role in neointimal formation after arterial injury in diabetes has not been described. METHODS AND RESULTS: Using a Zucker diabetic rat balloon injury model, we examined the role of P-selectin in the vascular inflammatory process and neointimal formation after balloon injury. Immunohistochemistry revealed that P-selectin was intensely expressed and that CD45-positive leukocyte infiltration was significantly increased after arterial injury. A single preprocedural intravenous administration of a recombinant P-selectin-soluble glycoprotein ligand-Ig inhibited CD45-positive leukocyte accumulation and suppressed neointimal formation in the Zucker diabetic rat model. CONCLUSIONS: These results suggest that reduction of P-selectin-mediated leukocyte activation with the use of recombinant P-selectin-soluble glycoprotein ligand-Ig decreases the inflammatory response and limits neointimal formation after balloon injury in diabetes.

Animals↗
PubMed2002

Identification of differentially expressed genes in normal and malignant prostate by electronic profiling of expressed sequence tags.

Differentially expressed genes between corresponding normal and cancertissue can advance our understanding of the molecular basis of malignancy and potentially serve as biomarkers or prognostic markers of malignancy. To identify differentially expressed genes in prostate cancer, we used a procedure combining electronic expression profiling of the prostate expressed sequence tag (EST) database and molecular biology techniques. A novel electronic expression-profiling algorithm was developed to search publicly available EST sequences for genes that show significant differential expression in prostate cancer compared with normal prostate tissue. Approximately 600 genes expressed in prostate were identified through adequate EST counts of ESTs for electronic profiling. Of these 600 genes, 9 showed statistically significant differences in their EST counts between cancer and normal prostate and were further analyzed. The predictions associated with electronic profiling were experimentally verified for two genes, cysteine-rich secretory protein 3 (CRISP-3) and deadenylating nuclease (DAN), using real-time reverse transcription-PCR with total RNA extracted from cells isolated by laser capture microdissection. In five of five Gleason score 6 cancer cases, CRISP-3 expression was increased >50 fold, whereas the expression of DAN was reduced by >80%.

Algorithms↗
PubMed2002

Score test for mapping quantitative-trait loci with sibships of arbitrary size when the dominance effect is not negligible.

In the linakge analysis of quantitative traits, an additive model that assumes no dominance effect is often adopted. Intuitively, when the no-dominance-effect assumption does not hold, such a practice does not make efficient use of the data, and its power to detect linkage can be improved. Here we introduce a score statistic for detecting quantitative trait loci when the dominance effect is not neglible or the dominance effect is a concern. This statistic is derived from a normal likelihood function for sibships of arbitrary size. In the derivation, the inherent genetic constraints on model parameters are fully taken into consideration. This score statistic is asymptotically equivalent to the corresponding likelihood ratio statistic, but it is much easier to compute. The asymptotic distribution of this statistic is derived, which is a mixture of chi(0) (2), chi(1) (2), and chi(2) (2). Weights for distribution components are functions of the informativeness of the marker data. The type I error rate and the power of the proposed statistic in finite sample are evaluated via simulations.

Chromosome Mapping↗
PubMed2002

Effect of anti-tumor necrosis factor-alpha polyclonal antibody on restenosis after balloon angioplasty in a rabbit atherosclerotic model.

Inflammation has been postulated to contribute to restenosis after balloon angioplasty. Tumor necrosis factor (TNF)-alpha is a pleiotropic proinflammatory cytokine involved in many features of inflammation. We examined the tissue expression pattern of TNF-alpha and the inflammatory response to arterial injury, and the effects of a goat anti-rabbit-TNF-alpha polyclonal antibody on tissue TNF-alpha expression, inflammation and restenosis in a rabbit atherosclerotic model. At different time points following air dessication and subsequent balloon injury, fresh rabbit femoral artery tissues were homogenized and analyzed for TNF-alpha levels by quantitative TNF-alpha bioassay. Rabbits were treated with a goat anti-rabbit-TNF-alpha polyclonal antibody, Serum and tissue TNF-alpha neutralization, macrophage infiltration (as an indicator of inflammation), and neointimal areas were determined. Balloon angioplasty increased tissue TNF-alpha expression 100000-fold over baseline, and this increase persisted over 6 days after arterial injury, serum anti-TNF-alpha antibody levels were sufficient to neutralize tissue TNF-alpha activity by 60-75%, macrophage infiltration was suppressed, but did not decrease the neointimal formation. These data indicate that tissue TNF-alpha levels were markedly increased after balloon angioplasty. Anti-TNF-alpha treatment was sufficient to neutralize tissue TNF-alpha activity, reduce inflammation, but did not inhibit neointimal formation following balloon angioplasty in a rabbit atherosclerotic model.

Angioplasty, Balloon↗
PubMed2002

Novel sustained-release implant of herb extract using chitosan.

Chitosan (CS), a naturally occurring high-molecule polymer, which is stable in vivo, has proved to be a useful biomaterial. The extract of danshen (Radix Salviae miltiorrhizae), a medicinal herbal, was developed with CS-gelatin as an implant for the promotion of anastomosing and healing on muscles and tissues at the organic incision site in abdominal cavities. Measurements were made of the sustained release of tanshinone IIa, a marker component, from the material in vitro. The dissolution medium was assayed with an high-performance liquid chromatography method. Biodegradation studies of the material were also conducted both in vitro and in vivo. The film made of this material exhibited a sustained release effect. The release profile confirms to the Higuchi equation. At most about 20% of the incorporated drug were released over 15 days in a CS-gelatin (1:2) matrix. Drug release was found to be effectively controlled by the drug-amount loaded in the matrix. The improved film (CS/gelatin ratio: 1:16) can be hydrolyzed by lysozymes in vitro in 4 days. This film of 0.5 cm2 was implanted and degraded completely in rats over 28 days and the animals' wounds of abdominal incision healed well.

Abietanes↗
PubMed2002

Efficient score statistics for mapping quantitative trait loci with extended pedigrees.

The method of variance components is the method of choice for mapping quantitative trait loci (QTLs) with general pedigrees. Being a likelihood-based method, this method can be computation intensive even for nuclear families, and has excessive false positive rates under some situations. Here two efficient score statistics to detect QTLs are derived, one assumes that the candidate locus has no dominance effect, and the other one does not make such an assumption. These two score statistics are asymptotically equivalent to the method of variance components but they are easier to compute and more robust than the likelihood ratio statistic. The derivation of these score statistics is facilitated by separating the segregation parameters, the parameters that describe the distribution of the phenotypic value in the population, from the linkage parameters, the parameters that measure the effect of the candidate locus on the phenotypic value. Such a separation of the model parameters greatly reduces the number of parameters to be dealt with in the analysis of linkage. The asymptotic distributions of both score statistics are derived. Simulation studies indicate that, compared to the method of variance components, both score statistics have comparable or higher power, and their false-positive rates are closer to their respective nominal significance levels.

Chromosome Mapping↗
PubMed2002

Recombinant soluble P-selectin glycoprotein ligand-Ig (rPSGL-Ig) attenuates infarct size and myeloperoxidase activity in a canine model of ischemia-reperfusion.

The role of P-selectin in the process of reperfusion injury was evaluated using a recombinant soluble P-selectin glycoprotein ligand-Ig (rPSGL-Ig) in a canine coronary artery balloon occlusion model. rPSGL-Ig (1 mg/kg) or saline was given as an intravenous bolus 15 min before balloon deflation. Balloon occlusion time was 90 min followed by either 120 min or 7 days reperfusion. Infarct size was significantly reduced in the treatment group when expressed either as percentage of the area at risk or as absolute infarct size. Histological analysis showed that extensive myocardial injury and neutrophil infiltration were reduced by rPSGL-Ig. Myeloperoxidase activity (MPO) was significantly reduced in the risk area in the rPSGL-Ig group. Left ventricular ejection fraction was significantly less impaired during the first 24 h after reperfusion in the rPSGL-Ig group, although there was no difference by 7-day follow-up. Thus, administration of rPSGL-Ig decreases myocardial injury and inflammatory response for at least 7 days after reperfusion of ischemic myocardium.

Animals↗
PubMed2002

Inhibition of human phosphodiesterase 4A expressed in yeast cell GL62 by theophylline, rolipram, and acetamide-45.

AIM: To study the inductive expression of human phosphodiesterase 4A (hPDE4A) in yeast cell GL62 and investigate the inhibitory effects of theophylline, rolipram, and acetamide-45 on PDE4A activity of the expressed product in yeast cell GL62. METHODS: Yeast cell GL62 were transfected with human PDE4A gene cloned in the expression plasmid p138NB. Expression was induced by adding CuSO4 to a final concentration of 150 micromol/L, and the expressed product was extracted. The activity of PDE4A was detected by HPLC. RESULTS: Yeast cell GL62 expressed a certain protein at CuSO4 150 micromol/L, the size of the expressed product was between 62 kDa and 83 kDa, the activity of PDE4A of the expressed product at 3 h was in maximum (188 23) micromol/g/min, and the Km was (17.7 2.6) micromol/L. Theophylline, rolipram, and acetamide-45 could inhibit the activity of PDE4A extracted from yeast cell GL62. The IC50 (95 % confidence limits) of theophylline, rolipram, and acetamide-45 were 1642 (989-2727), 4.58 (3.45-6.08), and 275 (170-444) micromol/L respectively. CONCLUSION: PDE4A expressed in yeast cell GL62 is biologically active. Theophylline, rolipram, and acetamide-45 can inhibit the PDE4A activity. The expressed product in yeast cell GL62 may be used in the research work of PDE4 and its inhibitors.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed2002

[A video communication system for telemedicine].

In this paper, point to point video communication system based on internet is deeply studied. Meanwhile the application system designed practically is introduced. It is emphasized that video compression coding based on low bit rate stream with ITU-T H. 263 agreement and related international standards is realized.

Communication↗