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Biomedical subjects

Tao Li

Publications and source records attributed to Tao Li.

At least 91 records · Page 5Linked to original sources
PubMed2005

ISL1 physically interacts with BETA2 to promote insulin gene transcriptional synergy in non-beta cells.

ISL1 is a LIM homeodomain protein that plays an important role in insulin gene transcriptional activation and islet cell formation. BETA2 is a transcription factor in the basic helix-loop-helix (bHLH) family, which activates expression of tissue-specific genes in several developmental systems. In this study, we investigated the functional and physical interactions of ISL1 and BETA2 in promoting insulin gene transcription in non-beta cells. Using the luciferase assay, we demonstrated that ISL1 and BETA2 could activate insulin gene transcription synergistically. Co-immunoprecipitation also supported that ISL1 and BETA2 appear in one complex and this physical interaction mediates the synergy between these two proteins.

Basic Helix-Loop-Helix Proteins↗
PubMed2005

Research progress of vasculopathy in portal hypertension.

Portal hypertension, one of the vascular diseases, not only has lesions in liver, but also changes in vascular structures and functions of extrahepatic portal system, systemic system and pulmonary circulation. The pathological changes of vasculopathy in portal hypertension include remodeling of arterialized visceral veins, intimal injury of visceral veins and destruction of contractile structure in visceral arterial wall. The mechanisms of vasculopathy in portal hypertension may be attributed to the changes of hemodynamics in portal system, immune response, gene modulation, vasoactive substances, and intrahepatic blood flow resistance. Portal hypertension can cause visceral hyperdynamic circulation, and the development and progression of visceral vasculopathy, while visceral vasculopathy can promote the development and progression of portal hypertension and visceral hyperdynamic circulation in turn. The aforementioned three factors interact in the pathogenesis of hepatic cirrhosis-induced portal hypertension and are involved in hemorrhage due to varicose vein rupture.

Animals↗
PubMed2005

A phase I study of concurrent radiotherapy and capecitabine as adjuvant treatment for operable rectal cancer.

PURPOSE: To determine the maximum tolerated dose and the dose-limiting toxicity of capecitabine with standard radiotherapy (RT) as adjuvant treatment in patients with rectal cancer. METHODS AND MATERIALS: Patients with Stage II/III rectal cancer after surgery were eligible. Total RT dose was delivered as DT 50 Gy in fractions of 2.0 Gy/day for 5 weeks to the pelvic area. Capecitabine was administered concurrently with RT in escalating doses, twice daily with a 12-h interval, for two cycles of 14 days separated by a 7-day rest. Dose-limiting toxicity included Grade 3 or Grade 4 hematologic and nonhematologic toxicity. RESULTS: Twenty-four patients were enrolled at the following dose levels: 1,000 (3 patients), 1,200 (3 patients), 1,400 (3 patients), 1,500 (3 patients), 1,600 (6 patients), and 1,700 mg/m2/day (6 patients). Dose-limiting toxicity was observed in 1 patient at 1,600 mg/m2/day (Grade 3 diarrhea) and in 2 patients at 1,700 mg/m2/day (1 patient had Grade 3 and 1 Grade 4 diarrhea). CONCLUSION: The maximum tolerated dose (MTD) of capecitabine given concurrently with RT was 1,600 mg/m2, daily from the 1st to the 14th day, with a 7-day rest, for two cycles.

Adult↗
PubMed2005

IVF results in de novo DNA methylation and histone methylation at an Igf2-H19 imprinting epigenetic switch.

Recent studies suggest that IVF and assisted reproduction technologies (ART) may result in abnormal genomic imprinting, leading to an increased frequency of Angelman syndrome (AS) and Beckwith-Weidemann syndrome (BWS) in IVF children. To learn how ART might alter the epigenome, we examined morulas and blastocysts derived from C57BL/6J X M. spretus F1 mice conceived in vivo and in vitro and determined the allelic expression of four imprinted genes: Igf2, H19, Cdkn1c and Slc221L. IVF-derived mouse embryos that were cultured in human tubal fluid (HTF) (Quinn's advantage) media displayed a high frequency of aberrant H19 imprinting, whereas in vivo and IVF embryos showed normal maternal expression of Cdkn1c and normal biallelic expression of Igf2 and Slc221L. Embryonic stem (ES) cells derived from IVF blastocysts also showed abnormal Igf2/H19 imprinting. Allele-specific bisulphite PCR reveals abnormal DNA methylation at a CCCTC-binding factor (CTCF) site in the imprinting control region (ICR), as the normally unmethylated maternal allele acquired a paternal methylation pattern. Chromatin immunoprecipitation (ChIP) assays indicate an increase of lysine 4 methylation (dimethyl Lys4-H3) on the paternal chromatin and a gain in lysine 9 methylation (trimethyl Lys9-H3) on the maternal chromatin at the same CTCF-binding site. Our results indicate that de novo DNA methylation on the maternal allele and allele-specific acquisition of histone methylation lead to aberrant Igf2/H19 imprinting in IVF-derived ES cells. We suggest that ART, which includes IVF and various culture media, might cause imprinting errors that involve both aberrant DNA methylation and histone methylation at an epigenetic switch of the Igf2-H19 gene region.

Animals↗
PubMed2005

Membrane transformation during malaria parasite release from human red blood cells.

Three opposing pathways are proposed for the release of malaria parasites from infected erythrocytes: coordinated rupture of the two membranes surrounding mature parasites; fusion of erythrocyte and parasitophorus vacuolar membranes (PVM); and liberation of parasites enclosed within the vacuole from the erythrocyte followed by PVM disintegration. Rupture by cell swelling should yield erythrocyte ghosts; membrane fusion is inhibited by inner-leaflet amphiphiles of positive intrinsic curvature, which contrariwise promote membrane rupture; and without protease inhibitors, parasites would leave erythrocytes packed within the vacuole. Therefore, we visualized erythrocytes releasing P. falciparum using fluorescent microscopy of differentially labeled membranes. Release did not yield erythrocyte ghosts, positive-curvature amphiphiles did not inhibit release but promoted it, and release of packed merozoites was shown to be an artifact. Instead, two sequential morphological stages preceded a convulsive rupture of membranes and rapid radial discharge of separated merozoites, leaving segregated internal membrane fragments and plasma membrane vesicles or blebs at the sites of parasite egress. These results, together with the modulation of release by osmotic stress, suggest a pathway of parasite release that features a biochemically altered erythrocyte membrane that folds after pressure-driven rupture of membranes.

Animals↗
PubMed2005

Effect of ligand of peroxisome proliferator-activated receptor gamma on the biological characters of hepatic stellate cells.

AIM: To study the effect of rosiglitazone, which is a ligand of peroxisome proliferator-activated receptor gamma (PPARgamma), on the expression of PPARgamma in hepatic stellate cells (HSCs) and on the biological characteristics of HSCs. METHODS: The activated HSCs were divided into three groups: control group, 3 micromol/L rosiglitazone group, and 10 micromol/L rosiglitazone group. The expression of PPARgamma, alpha-smooth muscle actin (alpha-SMA), and type I and III collagen was detected by RT-PCR, Western blot and immunocytochemical staining, respectively. Cell proliferation was determined with methylthiazolyltetrazolium (MTT) colorimetric assay. Cell apoptosis was demonstrated with flow cytometry. RESULTS: The expression of PPARgamma at mRNA and protein level markedly increased in HSCs of 10 micromol/L rosiglitazone group (t value was 10.870 and 4.627 respectively, P<0.01 in both). The proliferation of HSCs in 10 micromol/L rosiglitazone group decreased significantly (t = 5.542, P<0.01), alpha-SMA expression level and type I collagen synthesis ability were also reduced vs controls (t value = 10.256 and 14.627 respectively, P<0.01 in both). The apoptotic rate of HSCs significantly increased in 10 micromol/L rosiglitazone group vs control (chi(2) = 16.682, P<0.01). CONCLUSION: By increasing expression of PPARgamma in activated HSCs, rosiglitazone, an agonist of PPARgamma, decreases alpha-SMA expression and type I collagen synthesis, inhibits cell proliferation, and induces cell apoptosis.

Actins↗
PubMed2005

catena-Poly[[[mu-1,4-bis(imidazol-1-ylmethyl)benzene-kappa2N3:N3']bis[dichlorocopper(II)]]-bis[mu-1,4-bis(imidazol-1-ylmethyl)benzene]-1:1'kappa2N3:N3';2:2'kappa2N3:N3'].

The title compound, [Cu2Cl4(bix)3]n [bix is 1,4-bis(imidazol-1-ylmethyl)benzene, C14H14N4], has been synthesized by the hydrothermal method. The copper(II) center has a five-coordinate trigonal-bipyramidal geometry. Each bix ligand binds with two CuII ions, forming ladder-like structures which are connected by pi-pi stacking interactions to form a two-dimensional network.

Journal Article↗
PubMed2005

Molecular physiology of vesicular glutamate transporters in the digestive system.

Glutamate is the major excitatory neurotransmitter in the mammalian central nervous system (CNS). Packaging and storage of glutamate into glutamatergic neuronal vesicles require ATP-dependent vesicular glutamate uptake systems, which utilize the electrochemical proton gradient as a driving force. Three vesicular glutamate transporters (VGLUT1-3) have been recently identified from neuronal tissue where they play a key role to maintain the vesicular glutamate level. Recently, it has been demonstrated that glutamate signaling is also functional in peripheral neuronal and non-neuronal tissues, and occurs in sites of pituitary, adrenal, pineal glands, bone, GI tract, pancreas, skin, and testis. The glutamate receptors and VGLUTs in digestive system have been found in both neuronal and endocrinal cells. The glutamate signaling in the digestive system may have significant relevance to diabetes and GI tract motility disorders. This review will focus on the most recent update of molecular physiology of digestive VGLUTs.

Amino Acid Transport Systems, Acidic↗
PubMed2005

[Downregulation of transforming growth factor-beta1 and platelet-derived growth factor gene expression by interleukin-10 in murine hepatic stellate cells in response to experimental liver injury].

OBJECTIVE: To investigate the effect of interleukin-10 (IL-10) on the expression of transforming growth factor-beta(1) (TGFbeta(1)) and platelet-derived growth factor (PDGF) in hepatic stellate cells (HSC) during liver injury. METHODS: The adenovirus vector (the titer was 1 x 10(7) efu/ml) encoded IL-10 gene was used to transfect the rat via the vein of caudal. At the same time, CCl(4) was injected into rat by a hypodermic injection. These processes went on twice a week. After eight weeks, the liver were perfused with collagenase IV and purified by density gradient centrifugation with Nycodenz for separate HSC. The level of IL-10 was measured by ELISA method; The expression of PDGF and TGFbeta(1) in HSC was detected by semi-quantitative RT-PCR and Western-blot methods. RESULTS: The level of IL-10 in therapy group (adenovirus vector encoding IL-10 gene group) was higher than that in non-therapy group (adenovirus vector without IL-10 gene and PBS group); The expression of TGFbeta(1) mRNA, TGFbeta(1) protein and PDGF mRNA, PDGF protein in therapy group were significantly lower than that in non-therapy group (P < 0.05). CONCLUSION: Downregulating the TGFbeta(1) and PDGF expression could be the passageway by which IL-10 alleviate the degree of proliferation and activation in hepatic stellate cells.

Animals↗
PubMed2005

The APOC3 SstI polymorphism is weakly associated with sporadic Alzheimer's disease in a Chinese population.

In order to clarify the relationship of apolipoprotein CIII (APOC3) polymorphism and sporadic Alzheimer's disease (AD) in Chinese, 165 sporadic AD patients and 174 age-matched elderly individuals were genotyped for the APOC3 SstI and apolipoprotein E (APOE) HhaI polymorphisms. As the result, the APOC3 3017G allele was found to be associated with AD in APOE epsilon4 allele noncarriers (chi2=4.433, P=0.035), and the risk estimate of allele C versus G resulted in an OR of 1.56 (95% CI: 1.03-2.37), although in total no significant differences of allelic or genotypic frequencies between patients and controls were found. Assessment of interaction between APOE epsilon4 and APOC3 3017G status presented an adjusted odds ratio of 0.62 (95% CI: 0.37-1.03) with a borderline significant P-value (P=0.066). Therefore, we conclude that the rare APOC3 G allele may offer some protection against the development of sporadic AD in APOE epsilon4 noncarriers in Chinese.

Aged↗
PubMed2005

Establishment of human embryonic stem cell line from gamete donors.

BACKGROUND: Human embryonic stem (HES) cell derived from human blastocyst can be propagated indefinitely in the primitive undifferentiated state while remaining pluripotent. It has exciting potential in human developmental biology, drug discovery, and transplantation medicine. But there are insufficient HES cell lines for further study. METHODS: Three oocyte donors were studied, and 3 in vitro fertilization (IVF) cycles were carried out to get blastocysts for the establishment of HES cell line. Isolated from blastocysts immunosurgically, inner cell mass (ICM) was cultured and propagated on mouse embryonic fibroblasts (MEFs). Once established, morphology, cell surface markers, karyotype and differentiating ability of the cell line were thoroughly analyzed. RESULTS: Four ICMs from 7 blastocysts were cultured on MEFs. After culture, one cell line (cHES-1) was established and met the criteria for defining human pluripotent stem cells including a series of markers used to identify pluripotent stem cells, morphological similarity to primate embryonic stem cells and HES reported else where. Normal and stable karyotype maintained over 60 passages, and demonstrated ability to differentiate into a wide variety of cell types. CONCLUSIONS: HES cell lines can be established from gamete donors at a relatively highly efficient rate. The establishment will exert a widespread impact on biomedical research.

Blastocyst↗
PubMed2005

Five cases of male eating disorders in Central China.

OBJECTIVE: Despite the recent surge of eating disorders among women in large Asian cities, male eating disorder cases remain rare. The current article described 5 male eating disorder cases that presented within a period of 2 years in Wuhan, a city in central China. METHODS: The authors described 4 cases of anorexia nervosa (2 restrictive, 2 bulimic) and 1 case of normal weight bulimia nervosa. RESULTS: Fear of fat was reported for all 5 cases, and none of the cases reported homosexuality. DISCUSSION: Sociocultural changes and westernization most probably accounted for the increasing incidence of eating disorders among male and female youngsters in China today.

Adolescent↗
PubMed2005

Increased heme oxygenase-1 expression in infarcted rat hearts following human bone marrow mesenchymal cell transplantation.

Heme oxygenase-1 (HO-1) plays an important role in oxidative stress and recent studies indicate that it is a graft survival protein in cardiac and liver transplant models. In this study, we investigated the relation between the expressions of HO-1 and the effects of human bone marrow mesenchymal cells (MSCs) transplantation to xenogenic rat hearts with experimental myocardial infarction (MI). A total of 5 x 10(6) cells in 100 microl PBS or equal volume PBS alone were injected into the ischemic zones immediately post-MI. At 1, 3, and 7 days post-MI, cardiac function was evaluated by echocardiography, the expression of HO-1 was assessed by real-time PCR and Western blot, the localization of HO-1 protein was determined under immunofluorescence microscopy. The infarct size was examined by histology. The numbers of Hoechst-33342 positive MSCs were evaluated under immunofluorescence microscopy and also by flow cytometry after isolation from the host hearts. The results indicated that the HO-1 expressions were markedly increased at both mRNA and protein levels in comparison with injection of PBS at each time point post MSCs transplantation (P < 0.01). HO-1 was revealed both in transplanted MSCs and recipient cardiomyocytes by immunofluorescence. Up-regulated HO-1 expression was accompanied by increase of the numbers of Hoechst-33342 positive MSCs, the reduction of infarct size, and the improvement of cardiac function. Transplantation of human MSCs could up-regulate HO-1 expression in infarct rat hearts, which might play an important role in protecting transplanted MSCs, cardiomyocytes survival, and cardiac function improvement during the early stage after MI.

Adult↗
PubMed2005

Cost of a ventilator-associated pneumonia in a shock trauma intensive care unit.

BACKGROUND: Nosocomial pneumonia and especially ventilator-associated pneumonia (VAP) are costly complications for the hospitalized patient. Nosocomial pneumonia has been estimated to cost $5,000 per episode, but the specific cost for a VAP has not been well estimated. As part of a successful performance improvement program in decreasing VAP from 10 VAPs/100 ICU admissions to 2.5 VAPs/100 ICU admissions, we examined the costs associated with VAP. METHODS: From January 1, 2002, through September 30, 2003, Shock Trauma Intensive Care Unit patients and charts were reviewed concurrently by an infection control practitioner for development of VAP as defined by National Nosocomial Infection Surveillance (NNIS) guidelines. Costs were obtained from the hospital's cost accounting software Transition Systems version 3.1.01 (TSI). All patients requiring greater than one day of mechanical ventilation were evaluated. Seventy patients with VAP and 70 patients without VAP were matched according to age and Injury Severity Score. Differences were compared using Kruskal-Wallis and two sample T-tests. Significance was considered for p < 0.05. RESULTS: The ICU cost difference was significant (p < 0.05) between the case-controlled patients with VAP ($82,195) and those without VAP ($25,037). There was also a significant increase in ICU length of stay (21.6 versus 6.4 days) and the number of ventilator days (17.7 versus 5.8; both, p < 0.05). Mortality was not different in the case-controlled population. A substantial portion of the increased cost of a VAP was from the increase in ICU length of stay ($1,861/day). Pharmacy, respiratory and "other" also accounted for the increases when cost distribution was analyzed. This translates into a cost avoidance of approximately $428,685 per 100 admissions to the ICU. CONCLUSIONS: Ventilator-associated pneumonia not only leads to a significant increase in ventilator days and ICU length of stay, but adds substantially to hospital costs. In our ICU, an episode of VAP costs $57,000 per occurrence.

Adult↗
PubMed2005

Mutation screening and association study of the neprilysin gene in sporadic Alzheimer's disease in Chinese persons.

Neprilysin has been reported to be a major beta-amyloid peptide (Abeta)-degrading enzyme. The decreased expression and activity of it may contribute to the development of Alzheimer's disease by promoting the accumulation of Abeta. We used denaturing high-performance liquid chromatography to screen the neprilysin gene (NEP) for single nucleotide polymorphisms (SNPs) in 257 Chinese sporadic Alzheimer's disease patients and 242 cognitive normal controls. As a result, eight novel and one known SNP were identified. Three of them, -204G-->C in the promoter region, IVS17-294C-->T, and IVS22+36C-->A showed a significant association with Alzheimer's disease (p = .006,.017, and.003, respectively). Subsequent haplotype analysis provided further evidence of the association (global p < .0001 for the three SNPs mentioned above, and global p < .01 for the eight SNPs with rare allele frequency > 1%). These findings indicate that genetic variations within or extremely close to NEP might influence the susceptibility to Alzheimer's disease in Chinese persons.

Aged↗
PubMed2005

Clustering genes using gene expression and text literature data.

Clustering of gene expression data is a standard technique used to identify closely related genes. In this paper, we develop a new clustering algorithm, MSC (Multi-Source Clustering), to perform exploratory analysis using two or more diverse sources of data. In particular, we investigate the problem of improving the clustering by integrating information obtained from gene expression data with knowledge extracted from biomedical text literature. In each iteration of algorithm MSC, an EM-type procedure is employed to bootstrap the model obtained from one data source by starting with the cluster assignments obtained in the previous iteration using the other data sources. Upon convergence, the two individual models are used to construct the final cluster assignment. We compare the results of algorithm MSC for two data sources with the results obtained when the clustering is applied on the two sources of data separately. We also compare it with that obtained using the feature level integration method that performs the clustering after simply concatenating the features obtained from the two data sources. We show that the z-scores of the clustering results from MSC are better than that from the other methods. To evaluate our clusters better, function enrichment results are presented using terms from the Gene Ontology database. Finally, by investigating the success of motif detection programs that use the clusters, we show that our approach integrating gene expression data and text data reveals clusters that are biologically more meaningful than those identified using gene expression data alone.

Artificial Intelligence↗
PubMed2005

A novel in vitro transcription method for producing siRNAs without specific sequence requirements.

RNA interference is a powerful genetic approach for silencing of target genes in which 21-23 nucleotide small interfering RNAs (siRNAs) work as sequence-specific RNA interference (RNAi) mediators. Production of siRNAs by in vitro transcription is a useful method that it is simple, effective, and inexpensive. Commonly used in vitro transcription promoters use guanine as the transcription start nucleotide. This method is, therefore, restricted to generating siRNAs with target sequences of 5'-NNGN17C. Here we report a modified in vitro transcription method, in which pre-siRNAs containing the 5' overhanging single-stranded leader sequence are first synthesized, then a DNA oligonucleotide complementary to the leader sequence is added to form a RNA-DNA hybrid, which is removed using RNase H to obtain desired siRNAs. Using siRNAs prepared with this method, we successfully inhibited the expression of both exogenous and endogenous genes.

Base Sequence↗