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Biomedical subjects

Tao Li

Publications and source records attributed to Tao Li.

At least 109 records · Page 6Linked to original sources
PubMed2005

A hybrid neural network system for prediction and recognition of promoter regions in human genome.

This paper proposes a high specificity and sensitivity algorithm called PromPredictor for recognizing promoter regions in the human genome. PromPredictor extracts compositional features and CpG islands information from genomic sequence, feeding these features as input for a hybrid neural network system (HNN) and then applies the HNN for prediction. It combines a novel promoter recognition model, coding theory, feature selection and dimensionality reduction with machine learning algorithm. Evaluation on Human chromosome 22 was approximately 66% in sensitivity and approximately 48% in specificity. Comparison with two other systems revealed that our method had superior sensitivity and specificity in predicting promoter regions. PromPredictor is written in MATLAB and requires Matlab to run. PromPredictor is freely available at http://www.whtelecom.com/Prompredictor.htm.

Computational Biology↗
PubMed2005

Purified human bone marrow multipotent mesenchymal stem cells regenerate infarcted myocardium in experimental rats.

Recent findings suggest the feasibility of cardiac repair by transplantation of bone marrow mesenchymal stem cell (MSCs). However, it remains controversial regarding which cell type is the best source for transplanting into the ischemic heart because of lack of well-defined cell markers. In this study, we investigated the in vitro and in vivo effects of the novel multipotent marrow mesenchymal stem cells (MMSCs) from human bone marrow. Pluripotent markers (Oct4, Bmi1, and Abcg2) and vascular endothelial growth factor (VEGF) were detected by RT-PCR and immunofluorescence in MMSCs. Myocardial differentiation was induced in the expanded MMSC cultures by treatment with 5-azacyline. Expressions of VEGF in the animals transplanted with MMSCs were markedly increased in comparison with the animals injected with fibroblasts or saline at both mRNA and protein levels. VEGF expression was observed in both transplanted MMSCs and recipient cardiomyocytes by immunofluorescence. Confocal immunofluorescence microscopy revealed the specific markers for cardiomyocytes and endothelial cells in transplanted MMSCs 14 days after transplantation. Vessel count was increased and left ventricular function improved post-MMSC transplantation. These results indicate that transplantation of purified MMSCs from human bone marrow upregulated VEGF expression, enhanced angiogenesis, and improved the functional recovery following myocardial infarction in rats.

ATP Binding Cassette Transporter, Subfamily G, Mem↗
PubMed2005

[Regulation of hepatic stellate cell activation by interleukin-10/platelet derived growth factor/mitogen-activated protein kinase pathway].

OBJECTIVE: To investigate the regulatory effect of interleukin-10 (IL10) on the activation of hepatic stellate cells (HSC) through platelet derived growth factor (PDGF) and mitogen-activated protein kinase (MAPK) pathways. METHODS: HSC were divided randomly into 4 groups. Group 1 served as a control. HSC were incubated with 1 ng/ml, 5 ng/ml, and 25 ng/ml IL-10 in groups 2, 3 and 4. RT-PCR and western blot were used to detect the expression of PDGF and MAPK protein ERK and p38 and alpha-SMA. RESULTS: Compared with the control group, expressions of ERK, p38 and alpha-SMA of groups 2, 3 and 4 were significantly lower (F values were 240.47, 21.39, 28.86 respectively. IL-10 inhibited PDGF and MAPK protein ERK and p38 and alpha-SMA expression in a dose-dependent way. CONCLUSION: IL-10 inhibits activation of HSC through the PDGF/MAPK pathway.

Animals↗
PubMed2005

[The C224T polymorphism in the cathepsin D gene is not associated with sporadic Alzheimer's disease in Chinese].

Cathepsin D is the major lysosomal/endosomal aspartic protease and exhibits beta- and gamma-secretase-like activity in vitro. Data from German suggest that the C224T polymorphism in the Cathepsin D gene (CTSD) exon 2 is strongly associated with the risk for Alzheimer's disease (AD). Meanwhile other studies have not been able to replicate the result. It's necessary to determine the genotype of the polymorphism in CTSD in Chinese sporadic AD patients and age-matched controls with normal cognition and examine possible association of the polymorphism with the disease. We find no strong evidence of association between the CTSD C224T polymorphism and Chinese sporadic AD. Whereas there may be a weak synergistic interaction between ApoE epsilon4 and CTSD T allele.

Aged↗
PubMed2005

[Clinical trial and evaluation on comprehensive treatment on attack in acute stage: report of 522 cases].

OBJECTIVE: To investigate the clinical effect of the comprehensive treatment to acute stage of attack. METHODS: On the basis of the previous observation, the study of the randomization control with general treatment, treatment on acupuncture and western medical treatment were carried out. A comprehensive treatment on overall traditional Chinese medical differentiation according to the superiority of every treatment was assessed and evaluated in 522 patients with attack. RESULTS: The comprehensive treatment of cerebral infarction was superior to the western medicine treatment. General treatment, treatment on traditional Chinese medical differentiation, acupuncture group revealed different improvement on neural function, daily viability, cognitive function in various extent. CONCLUSION: The comprehensive treatment that based on overall traditional Chinese medical differentiation has advantage and characteristic. It has positive combined action to the attack and relevant to clinical setting, easier to popularization and application. Various appraising amount form has different evaluating effects in different stage.

Acupuncture Therapy↗
PubMed2005

[An in vivo study on interlukin-10 inhibiting the expression and secretion of collagen I and IV in hepatic stellate cells].

OBJECTIVES: To investigate the effect of interlukin-10 (IL-10) on expression and secretion of collagen I, IV in rat's hepatic stellate cells (HSC) of livers injured by CCl4. METHOD: The adenovirus vector encoded IL-10 gene was used to transfect rats with liver injury via the caudal veins. HSC were isolated and purified from the rat livers by collagenase IV perfusion and density gradient centrifugation with Nycodenz. The expression of collagen I, IV mRNA in HSC was detected by semi-quantitative RT-PCR method and the secretion of collagen I, IV in culture serum of HSC by ELISA method. The quantity of collagen was measured in the van Gieson stained histological liver preparations. RESULTS: The expression and secretion of collagen I, IV in the adenovirus vector encoding IL-10 gene group were significantly lower than those in the adenovirus vector without IL-10 gene group and the control group (P < 0.05). The quantity of collagen in the treatment group was lower than that in the control group. CONCLUSION: IL-10 can inhibit collagen I, IV expression and secretion in rat HSC.

Animals↗
PubMed2005

[Study on fingerprint of unfinished product of Nauclea injection].

OBJECTIVE: To establish HPLC fingerprints of unfinished product of Nauclea injection. METHOD: A high performance liquid chromatography assay was developed with an Agilent-Extend C18 column, a gradient elution:water-5% acetonitrile (10 min), 5% acetonitrile-10% acetonitrile (10-60 min), 50% acetonitrile-water (60-70 min), a 0.7 mL x min(-1) flow rate, at detection wavelength, 245 nm within a 70 min total elution time. RESULT: The RSD of relative retention time and peak area of coexist peaks meet to method requirement during the investigation of precision, stability and repeatibity trials. All of the 10 batches of samples share a high similarity. CONCLUSION: This method can be used to control the quality of unfinished product of Nauclea injection.

Chromatography, High Pressure Liquid↗
PubMed2005

[Changes in sensitivity of vascular smooth muscle to calcium and its role in the biphasic change in vascular reactivity following hemorrhagic shock in rats].

OBJECTIVE: To observe the change in sensitivity of vascular smooth muscle to calcium and its role in biphasic vascular reactivity following hemorrhagic shock (HS) in rats. METHODS: The superior mesenteric artery (SMA) obtained from rats with HS was used to assay the vascular reactivity and sensitivity to calcium by observing the contraction initiated by norepinephrine (NE) and Ca(2+) under depolarizing conditions (120 mmol/L K(+)) with isolated organ perfusion system. At different time points after shock, the relationship between vascular reactivity and sensitivity to calcium was analyzed. Meanwhile the effects of the angiotensin II (Ang II) and insulin, the calcium sensitivity regulating agents, on vascular reactivity were also observed. RESULTS: As compared with the control group, the cumulative dose-response curves of SMA to NE and Ca(2+) at early shock stages, i.e. immediately and 30 minutes after shock, shifted to the left, the maximal contractions (Emax) of NE and Ca(2+) were increased significantly (P<0.05 or P<0.01). But the cumulative dose-response curves of SMA to NE and Ca(2+) at late shock stage shifted to the right, and Emax of NE and Ca(2+) were significantly decreased (P<0.05 or P<0.01). Ang II increased the contractile response of SMA to NE and Ca(2+) when shock persisted for 2 hours, rendering the cumulative dose-response curves of NE and Ca(2+) shifted to the left (P<0.05 or P<0.01). But insulin decreased the contractile response of SMA to NE and Ca(2+) at early stage of shock, rendering the cumulative dose-response curves of NE and Ca(2+) shifted to the right (P<0.05 or P<0.01). CONCLUSION: Sensitivity of vascular smooth muscle to calcium following hemorrhagic displays a biphasic change. It plays important roles in biphasic vascular reactivity.

Animals↗
PubMed2005

[Study on changes in inflammatory cytokines and the relationship to multiple organ injury in rats with aspiration lung injury after fire-arm injury].

OBJECTIVE: To observe the phasic variations in concentrations of pro-inflammatory and anti-inflammatory cytokines, and to explore their potential roles in the occurrence and development process of multiple organ dysfunction. METHODS: Fire-arm induced aspiration lung injury model was replicated. The following parameters were observed: wet/dry weight ratio of rat's lungs, contents of albumin and lactate dehydrogenase (LDH), concentrations of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) and IL-4 in bronchial alveolar lavage fluid (BALF), contents of alanine amino transferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN), serum creatinine (SCr), and MB isoenzyme of creatine kinase (CK-MB). RESULTS: The wet/dry weight ratio of rat's lungs and contents of albumin and LDH in BALF increased with the passage of time. The concentration of TNF-alpha increased immediately after injury and reached the peak value at 2 hours. The concentration of IL-6 increased obviously 4 hours after injury, and maintained a high level from 4 hours to 24 hours. The concentration of IL-4 decreased from 6 hours to 8 hours after injury. The contents of ALT, AST, BUN, SCr and CK-MB increased continually after injury. CONCLUSION: Cytokines are the direct mediators for multiple organ failure (MOF), and MOF is triggered by TNF-alpha and a cascade of cytokine release, with a prolonged high-expression of IL-6. The loss of control of IL-4 aggravates the development of MOF.

Animals↗
PubMed2005

[The relationship between the beta-2-adrenergic receptor gene +46 Arg 16/Gly variant and serum level of low density lipoprotein-cholesterol in Kazakans of Xinjiang].

OBJECTIVE: To investigate the distribution of beta-2-AR +46 A-->G variant in Kazakans of Xinjiang and the relationship of the variant with low density lipoprotein-cholesterol (LDL-C) level in this population. METHODS: The genotypes of beta-2-AR gene Arg16/Gly variant were detected by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique in 506 Kazakans with age from 30 to 69, and its distribution and relationship to LDL-C level were investigated. RESULTS: (1) The frequencies of genotypes AA, AG, GG and alleles A, G of beta-2-AR +46 variant in this population were 0.310, 0.455, 0.235 and 0.538, 0.462 respectively, which were accorded with Hardy-Weinberg equilibrium. (2) The Gly16/Gly genotype had highest LDL-C level in the three genotypes, and were significantly higher than Arg16/Gly genotype (P < 0.05). (3) Comparing the effect of beta-2-AR gene +46 variant on serum lipid in males with females, we found that females with Gly16/Gly genotype had the highest level of serum LDL-C. CONCLUSIONS: These data show that Gly16/Gly genotype of beta-2-AR gene +46 A-->G variant is associated with higher level of serum LDL-C in this population, especially in female.

Adult↗
PubMed2005

[Study on the geographic information system databases regarding the control of schistosomiasis in Zhongxiang, Hubei province, China].

OBJECTIVE: Using geographic information system (GIS) and the remote sensing techniques (RS), we developed a schistosomiasis database and geographic distribution map in Zhongxiang city,Hubei province in order to display and analyze the endemic situation longitudinally after the water conservancy project is completed. METHODS: Epidemiological data of schistosomiasis and the correlated climate and hydrology data for the last 30 years were collected and the relevant GIS databases were established under Artificial Neural Networks(ANN) and network training of Landsat TM images. RESULTS: GIS database of schistosomiasis in Zhongxiang city, Hubei province and its vicinity areas were developed including 1 maps regarding the epidemic situation of schistosomiasis. The areas of snail distributing were 4.4 hm2, 8.2 hm2, 24 hm2, 130.4 hm2, 8.13 hm2 and 7.53 hm2, respectively. CONCLUSION: The maps created by GIS database and RS techniques supported the complicated query on space and property, providing a new way in keeping,updating and analyzing available data. The techniques used should be able to provide evidence for the control of schistosomiasis to this water conservancy project.

Animals↗
PubMed2004

Differential induction of apoptosis by LPS and taxol in monocytic cells.

Numerous microbial as well as other stimulants including lipopolysaccharide and taxol can activate TLR4, and elicit diverse downstream signaling events including cytokine gene expression and cell growth regulation. With a mechanism not completely understood, different TLR4 stimulants induce distinct cellular responses. Our present studies showed that taxol, not LPS, induced cell apoptosis in human monocytic THP-1 cells, as indicated by PARP cleavage, as well as bcl-2 phosphorylation. Pretreatment of cells with LPS abolished subsequent taxol effect, suggesting that certain signaling components involved in taxol-mediated apoptosis were disrupted by LPS pretreatment. Since the decrease in IRAK-1 level closely accompanies prolonged LPS treatment in monocytic cells, we investigated the IRAK-1 status upon various taxol and LPS challenges. We observed that only LPS, not taxol, caused dramatic decrease in IRAK-1 protein levels. Using splenic macrophages harvested from IRAK-1 knockout and control mice, we further demonstrated that the presence of IRAK-1 is required for taxol-induced PARP cleavage.

Animals↗
PubMed2004

Peroxisome proliferator-activated receptor gamma ligands suppress liver carcinogenesis induced by diethylnitrosamine in rats.

AIM: Peroxisome proliferator-activated receptor gamma (PPARgamma) is known to regulate growth arrest and terminal differentiation of adipocytes and is used clinically as a new class of antidiabetic drugs. Recently, several studies have reported that treatment of cancer cells with PPARgamma ligands could induce cell differentiation and apoptosis, suggesting a potential application as chemopreventive agents against carcinogenesis. In the present study, 3 different kinds of PPARgamma ligands were subjected to the experiments to confirm their suppressive effects on liver carcinogenesis. METHODS: Three PPARgamma ligands, pioglitazone (Pio) (200 ppm), rosiglitazone (Rosi) (200 ppm), and troglitazone (Tro) (1,000 ppm) were investigated on the induction of the placental form of rat glutathione S-transferase (rGST P) positive foci, a precancerous lesion of the liver, and liver cancer formation using a diethylnitrosamine-induced liver cancer model in Wistar rats, and dose dependency of a PPARgamma ligand was also examined. RESULTS: PPARgamma ligands reduced the formation of rGST P-positive foci by diethylnitrosamine and induction of liver cancers was also markedly suppressed by a continuous feeding of Pio at 200 ppm. CONCLUSION: PPARgamma ligands are potential chemopreventive agents for liver carcinogenesis.

Alkylating Agents↗
PubMed2004

Molecular cloning and characterization of a human urate transporter (hURAT1) gene promoter.

We report the novel cloning and preliminary characterization of a human urate transporter (hURAT1) gene promoter. The transcription initiation site was mapped to a base 337 bp upstream of the ATG start codon by primer extension and 5'-RACE. The minimal functional promoter region is within 253 bp when the promoter/luciferase constructs were transfected into OK cells. The sex hormone testosterone significantly increases promoter activity, suggesting that hormonal regulation of hURAT1 is the root cause of observed differences in urate levels between males and females.

Base Sequence↗