Biomedical subjects

Jing Yang

Publications and source records attributed to Jing Yang.

At least 181 records · Page 10Linked to original sources

PubMed2003

[Role of leptin in the pathogenesis of obesity-related hypertension].

OBJECTIVE: To assess the role of leptin in the pathogenesis of obesity-related hypertension and the relationship between blood pressure (BP), and body mass index (BMI), insulin resistance and leptin were examined. METHODS: 560 non-diabetic men, aged 35 - 75, selected from volunteers of health screening test during 2 000 were divided into hypertension group (n = 321, BP >or= 140/90 mm Hg without antihypertensive medication). and normal blood pressure group (n = 239). The body weight, waist hip ratio,BP, plasma glucose, serum lipids, true insulin (TI) and leptin were measured after overnight fast. Insulin sensitivity was assessed by the HOMA insulin resistance index (HOMA-R). RESULTS: Fasting leptin level showed good correlation with BMI, fasting TI, HOMA-R, BP and also triglycerides (all P < 0.01). After adjustment for age, BMI and HOMA-R, serum leptin was still positively correlated to SBP (r = 0.11, P < 0.05), and was significantly higher in hypertensive subjects than in normotensive subjects (geometric mean 6.4 vs 4.7 micro g/L, P < 0.001). Logistic regression analysis demonstrated that leptin remained significantly associated with hypertension after adjustment for potentially confounding factors. CONCLUSION: Leptin may play an important role in the pathogenesis of obesity related hypertension.

Adult↗

PubMed2003

Split dnaE genes encoding multiple novel inteins in Trichodesmium erythraeum.

Three inteins were found when analyzing a pair of split dnaE genes encoding the catalytic subunit of DNA polymerase III in the oceanic N2-fixing cyanobacterium Trichodesmium erythraeum. The three inteins (DnaE-1, DnaE-2, and DnaE-3) were clustered in a 70-amino acid (aa) region of the predicted DnaE protein. The DnaE-1 intein is 1258 aa long and three times as large as a typical intein, due to the presence of large tandem repeats in which a 57-aa sequence is repeated 17 times. The DnaE-2 intein has a more typical size of 428 aa with putative protein splicing and endonuclease domains. The DnaE-3 intein is a split intein consisting of a 102-aa N-terminal part and a 36-aa C-terminal part encoded on the first and second split dnaE genes, respectively. Synthesis of a mature DnaE protein is predicted to involve expression of two split dnaE genes followed by two protein cis-splicing reactions and one protein trans-splicing reaction. Tandem repeats in the DnaE-1 intein inhibited the protein splicing activity of this intein when tested in Escherichia coli cells and may potentially regulate DnaE synthesis in vivo.

Amino Acid Sequence↗

PubMed2003

Inhibition of the D-fructose transporter protein GLUT5 by fused-ring glyco-1,3-oxazolidin-2-thiones and -oxazolidin-2-ones.

The glucose transporter 5 (GLUT5)-a specific D-fructose transporter-belongs to a family of facilitating sugar transporters recently enlarged by the human genome sequencing. Prompted by the need to develop specific photolabels of these isoforms, we have studied the interaction of conformationally locked D-fructose and L-sorbose derived 1,3-oxazolidin-2-thiones and 1,3-oxazolidin-2-ones to provide a rational basis for an interaction model. The inhibition properties of the D-fructose transporter GLUT5 by glyco-1,3-oxazolidin-2-thiones and glyco-1,3-oxazolidin-2-ones is now reported. In vitro, the fused-rings systems tested showed an efficient inhibition of GLUT5, thus bringing new insights on the interaction of D-fructose with GLUT5.

Animals↗

PubMed2003

Rate of protein evolution versus fitness effect of gene deletion.

Whether nonessential genes evolve faster than essential genes has been a controversial issue. To resolve this issue, we use the data from a nearly complete set of single-gene deletions in the yeast Saccharomyces cerevisiae to assess protein dispensability. Also, instead of the nematode, which was used previously but is only distantly related to S. cerevisiae, we use another yeast, Candida albicans, as a second species to estimate the evolutionary distances between orthologous genes in two species. Our analysis reveals only a weak correlation between protein dispensability and evolutionary rate. More important, the correlation disappears when duplicate genes are removed from the analysis. And surprisingly, the average rate of nonsynonymous substitution is considerably lower than that for single-copy genes in the yeast genome. This observation suggests that structural constraints are more important in determining the rate of evolution of a protein than dispensability because duplicate genes are on average more dispensable than single-copy genes. For duplicate genes, those with only a weak effect or no effect of deletion on fitness evolve on average faster than those with a moderate or strong effect of deletion on fitness, which in turn evolve on average faster than those with a lethal effect of deletion.

Candida albicans↗

PubMed2003

Toxicity screening by electrochemical detection of DNA damage by metabolites generated in situ in ultrathin DNA-enzyme films.

Rapid detection of DNA damage could serve as a basis for in vitro genotoxicity screening for new organic compounds. Ultrathin films (20-40 nm) containing myoglobin or cytochrome P450(cam) and DNA grown layer-by-layer on electrodes were activated by hydrogen peroxide, and the enzyme in the film generated metabolite styrene oxide from styrene. This styrene oxide reacted with double stranded (ds)-DNA in the same film, mimicking metabolism and DNA damage in human liver. DNA damage was detected by square wave voltammetry (SWV) by using catalytic oxidation with Ru(bpy)(3)(2+) (bpy = 2,2'-bipyridine) and by monitoring the binding of Co(bpy)(3)(3+). Damaged DNA reacts more rapidly than intact ds-DNA with Ru(bpy)(3)(3+), giving SWV peaks at approximately 1 V versus SCE that grow larger with reaction time. Co(bpy)(3)(3+) binds more strongly to intact ds-DNA, and its SWV peaks at 0.04 V decreased as DNA was damaged. Little change in SWV signals was found for incubations of DNA/enzyme films with unreactive organic controls or hydrogen peroxide. Capillary electrophoresis and HPLC-MS suggested the formation of styrene oxide adducts of DNA bases under similar reaction conditions in thin films and in solution. The catalytic SWV method was more sensitive than the Co(bpy)(3)(3+) binding assay, providing multiple measurements over a 5 min reaction time.

Biosensing Techniques↗

PubMed2003

Neighbor-constrained segmentation with 3D deformable models.

A novel method for the segmentation of multiple objects from 3D medical images using inter-object constraints is presented. Our method is motivated by the observation that neighboring structures have consistent locations and shapes that provide configurations and context that aid in segmentation. We define a Maximum A Posteriori(MAP) estimation framework using the constraining information provided by neighboring objects to segment several objects simultaneously. We introduce a representation for the joint density function of the neighbor objects, and define joint probability distributions over the variations of the neighboring positions and shapes of a set of training images. By estimating the MAP shapes of the objects, we formulate the model in terms of level set functions, and compute the associated Euler-Lagrange equations. The contours evolve both according to the neighbor prior information and the image gray level information. We feel that this method is useful in situations where there is limited inter-object information as opposed to robust global atlases. Results and validation from various experiments on synthetic data and medical imagery in 2D and 3D are demonstrated.

Algorithms↗

PubMed2003

Cells in G2/M phase increased in human nasopharyngeal carcinoma cell line by EBV-LMP1 through activation of NF-kappaB and AP-1.

Although previous studies showed that the principal oncoprotein encoded by Epstein-Barr virus, latent membrane protein 1(LMP1), could induce the nasopharyngeal carcinoma cells in G2/M phase increased, little is known about the target molecules and mechanisms. The present study demonstrated that LMP1 could induce the accumulation of p53 protein and upregulate its transactivity in a dose dependent manner, which resulted in the decrease of the kinase activity of cdc2/cyclin B complex and inducing arrest at G2/M phase through the activation of NF-kappaB and AP-1 signaling pathways, and the effect of NF-kappaB was more obvious than that of AP-1. This study provided some significant evidence for further elucidating the molecular mechanisms that LMP1 had effects on the surveillance mechanism of cell cycle and promoting the survival of transformed cells and tumorigenesis.

Blotting, Western↗

PubMed2003

Resting CD8 T cells recognize beta-galactosidase expressed in the immune-privileged retina and mediate autoimmune disease when activated.

Although the expression of class II major histocompatibility complex (MHC) in retina is extremely low, it is an established fact that activated CD4 T cells, specific for retinal antigens (Ags), mediate experimental autoimmune uveoretinitis (EAU). Conversely, CD8 T cells have not been shown to recognize Ag in the retina. This study investigated whether retinal-specific Ags are detected by class I MHC-restricted CD8 T cells. Using a CD8 T-cell clone (beta3) specific for an immunodominant epitope of beta-galactosidase (beta-gal), local Ag recognition was shown by transfer of activated beta3 cells into beta-gal transgenic (Tg) mice expressing beta-gal in the retina (hi-arr-beta-gal mice), or in the brain and eye (GFAP-beta-gal mice). Beta-gal-positive photoreceptor cells were damaged in the retina of hi-arr-beta-gal mice, and anterior segment disease was found in the eyes of GFAP-beta-gal mice. Ag recognition by resting CD8 T cells was also evaluated. Recovery of 5(6)-carboxyfluorescein diacetate N-succinimidyl ester (CFSE)-labelled beta3 cells from hi-arr-beta-gal mice was slightly decreased compared to recovery from B10.A mice, while recovery from GFAP-beta-gal mice was transiently increased. Conversely, recovery of CFSE- cells increased in hi-arr-beta-gal mice, consistent with an Ag-dependent response. The CFSE content of the CFSE+ population was unchanged relative to beta3 cells recovered from controls. Intracellular cytokine responses of beta3 cells recovered from hi-arr-beta-gal and GFAP-beta-gal mice correlated with the number of cells recovered, regardless of CFSE content. Even though their production of interferon-gamma and tumour necrosis factor-alpha was affected little by transfer into hi-arr-beta-gal recipients, the ability of beta3 cells to mediate delayed-type hypersensitivity was inhibited in hi-arr-beta-gal mice. These results show that resting CD8 T cells are affected by the presence of Ag that originates in retina and, when activated prior to transfer, mediate pathogenic autoimmunity against retinal and other ocular targets.

Adoptive Transfer↗

PubMed2003

Effects of testosterone undecanoate as a male contraceptive candidate on rat immunological features.

Testosterone undecanoate (TU) is under phase III clinical trial as a hormonal male contraceptive in China. Sex hormones can modulate the immune system. Female hormonal contraceptives may affect SIV/HIV-1 transmission. To evaluate the safety of TU and to understand whether long-term use of TU for a male contraceptive affects users' immunological features, adult male rats were treated for a 32-week TU-treated phase at the dose of 20 mg TU/kg body weight and a 24-week recovery phase. The reproductive and immunological parameters of 4-6 rats in each subgroup were examined at the stated time point. The mean sperm count and viability in the treated rats were significantly suppressed (p < 0.01). In the TU-treated group: the mean blood leukocyte and lymphocyte counts; the proliferation indexes of T cells from peripheral blood mononuclear cells (PBMC) and spleen; and, of B cells from spleen, as well as the mean counts of blood T, NK, and B cells decreased in comparison with those of control group. These decreases were not significant (p > 0.01). Similarly, the mean serum IgM, IgG, and IgA levels and complement activity in TU-treated rats were lower than those in control group (p > 0.01), and the changes in the antibody levels of the examined genital secretions were not significant (p > 0.01). The changes in the thickness of urethra epithelium, and in secretory component (SC) expression in genitals were not observed in the treated group. These results demonstrated that long-term supraphysiological TU injection did not obviously affect the examined rat immunological parameters.

Animals↗

PubMed2003

CD45-positive cells of the retina and their responsiveness to in vivo and in vitro treatment with IFN-gamma or anti-CD40.

PURPOSE: The ability to mount antigen-specific immune reactions in the retina demonstrates local recognition of retinal antigens. However, properties of antigen-presenting cells (APCs) of the retina are uncertain. The current study was undertaken to look for evidence of CD45(+) cells with APC potential in the retina and to examine their in situ and in vitro responses to IFN-gamma and anti-CD40, two stimuli known to upregulate activities associated with antigen presentation. METHODS: Mice were pretreated with systemic or intracameral (IC) inoculations of IFN-gamma or anti-CD40. Retinas were harvested, enzymatically dissociated, positively selected with anti-CD45, and analyzed by flow cytometry with antibodies known to identify APCs. RESULTS: The most common CD45(+) retinal cells were CD11b(+), F4/80(+), CD8 alpha(+), CD80(+), and major histocompatibility complex (MHC) class II(lo), a phenotype characteristic of central nervous system (CNS) microglia (MG). There was also a small population of DEC-205(+) cells and a smaller number of CD11c(+) cells, both markers of dendritic cells (DCs). IC inoculation of IFN-gamma led to an increase in the number of CD45(+) cells and a modest upregulation of MHC class II on CD11b(+) cells. IC inoculation of anti-CD40 also increased the total number of CD45(+) cells and the number of CD11b(+) cells, but increases in CD80 and MHC class II expression on CD11b(+) cells were insignificant. After anti-CD40 treatment, CD45(hi)11c(+) cells increased in number and altered their expression of CD11b. CONCLUSIONS: Retinal MG were readily identified as the most numerous population. A small population of cells with perivascular cell (PVC)-like properties was found. They were CD45(hi)11c(+), some had elevated MHC class II, and they were affected by anti-CD40 treatment in vivo. No conventional DCs were found, although there was a distinct DEC-205(+) population. Overall, the effects of IFN-gamma and anti-CD40 treatment were attenuated in the retina in vivo and also on CD45(+) cells in culture, compared with the control.

Animals↗

PubMed2003

Mouse models of Alzheimer's disease: the long and filamentous road.

Alzheimer's disease (AD) is characterized by memory impairment leading to dementia, deposition of amyloid plaques and neurofibrillary tangles (NFTs), and neuronal loss. The major component of plaques is the amyloid beta peptide, A beta, whereas NFTs contain hyperphosphorylated forms of the microtubule-associated protein tau (tau). Familial AD (FAD) mutations either elevate A beta synthesis by favoring 'secretase' of the Alzheimer beta-amyloid precursor protein (APP) or enhance the fibrillogenic properties of this peptide. Mutations in the tau gene cause a different disease denoted FTPD-17, but suggest that the aberrant forms of tau seen in AD are unlikely to be benign. These findings imply a complex pathogenic cascade in AD and important goals of transgenic modeling are to capture and stratify this pathogenic process. Several laboratories have created APP transgenic (Tg) mice that exhibit AD-like amyloid pathology and A beta burdens. These Tg lines also exhibit deficits in spatial reference and/or working memory, with immunization against A beta attenuating both AD-associated phenotypes. Tangle-like pathologies are observed in mice expressing FTPD-17 mutant forms of tau, but florid tau pathologies based upon the wild type (wt) tau isoforms present in AD have proven more elusive. Creation of animal models with robust amyloid and tau pathologies, yet free of irrelevant confounding pathologies, remains a major objective in this field.

Alzheimer Disease↗

PubMed2003

5-amino-imidazole carboxamide riboside increases glucose transport and cell-surface GLUT4 content in skeletal muscle from subjects with type 2 diabetes.

AMP-activated protein kinase (AMPK) activation by AICAR (5-amino-imidazole carboxamide riboside) is correlated with increased glucose transport in rodent skeletal muscle via an insulin-independent pathway. We determined in vitro effects of insulin and/or AICAR exposure on glucose transport and cell-surface GLUT4 content in skeletal muscle from nondiabetic men and men with type 2 diabetes. AICAR increased glucose transport in a dose-dependent manner in healthy subjects. Insulin and AICAR increased glucose transport and cell-surface GLUT4 content to a similar extent in control subjects. In contrast, insulin- and AICAR-stimulated responses on glucose transport and cell-surface GLUT4 content were impaired in subjects with type 2 diabetes. Importantly, exposure of type 2 diabetic skeletal muscle to a combination of insulin and AICAR increased glucose transport and cell-surface GLUT4 content to levels achieved in control subjects. AICAR increased AMPK and acetyl-CoA carboxylase phosphorylation to a similar extent in skeletal muscle from subjects with type 2 diabetes and nondiabetic subjects. Our studies highlight the potential importance of AMPK-dependent pathways in the regulation of GLUT4 and glucose transport activity in insulin-resistant skeletal muscle. Activation of AMPK is an attractive strategy to enhance glucose transport through increased cell surface GLUT4 content in insulin-resistant skeletal muscle.

Aminoimidazole Carboxamide↗

PubMed2003

Triptolide inhibits the growth and metastasis of solid tumors.

Triptolide (TPL), a diterpenoid triepoxide purified from the Chinese herb Tripterygium wilfordii Hook F, was tested for its antitumor properties in several model systems. In vitro, TPL inhibited the proliferation and colony formation of tumor cells at extremely low concentrations (2-10 ng/ml) and was more potent than Taxol. Likewise, in vivo, treatment of mice with TPL for 2-3 weeks inhibited the growth of xenografts formed by four different tumor cell lines (B16 melanoma, MDA-435 breast cancer, TSU bladder cancer, and MGC80-3 gastric carcinoma), indicating that TPL has a broad spectrum of activity against tumors that contain both wild-type and mutant forms of p53. In addition, TPL inhibited experimental metastasis of B16F10 cells to the lungs and spleens of mice. The antitumor effect of TPL was comparable or superior with that of conventional antitumor drugs, such as Adriamycin, mitomycin, and cisplatin. Importantly, tumor cells that were resistant to Taxol attributable to the overexpression of the multidrug resistant gene 1 were still sensitive to the effects of TPL. Studies on cultured tumor cells revealed that TPL induced apoptosis and reduced the expression of several molecules that regulate the cell cycle. Taken together, these results suggest that TPL has several attractive features as a new antitumor agent.

Animals↗

PubMed2003

[Role of tumor metastasis suppressor gene KAI1 in development of colorectal cancer].

BACKGROUND & OBJECTIVE: The study of tumor metastasis suppressor gene KAI1 in colorectal cancer (CRC) is limited nowadays. There are some controversies about the expression of KAI1 and its relationship with pathologic classification of CRC, and up today, the reports of the correlation between KAI1 and the prognosis of CRC still be few. This study was designed to investigate the role of KAI1 in development of CRC and its value in predicting the prognosis of CRC. METHODS: The expression of KAI1 in 91 cases of primary CRC and 25 cases of lymph node metastases were determined using immunohistochemistry. RESULTS: The positive cases of KAI1 in primary CRC were 54 (59.3%), the weak positive cases were 22 (24.2%), the negative cases were 15 (16.5%). KAI1 expression reduced significantly in the cases with low differentiation, lymph node metastasis and distant metastatic tumor (P< 0.01). The positive expression rate of KAI1 in the patients who survived more than 5 years (67.14%) was higher than that in the patients who survived less than 5 years (33.33%) (P< 0.05). The 5-year survival rates of the patients with positive, weak positive, and negative expression of KAI1 decreased in turn (87.04%, 63.34%, 60.00%; P< 0.05). KAI1 expression in lymph node metastases was lower than that in primary locus (P< 0.05). CONCLUSION: The abnormal expression of KAI1 participates in malignant progression of CRC. Detecting the expression of KAI1 probably possesses clinical significance in evaluating the differentiation, lymph node metastasis,and distant metastasis of CRC, and predicting the prognosis of CRC.

Adult↗

PubMed2003

[Clinical application of retrograde cerebral perfusion for brain protection during the surgery of ascending aortic aneurysm: 50 cases report].

OBJECTIVE: To assess retrospectively the effects of different protective methods on brain in ascending aortic aneurysm surgery. METHODS: In 65 patients, aneurysm was dissected to the aortic arch or right arch. To protect brain, deep hypothermic circulatory arrest (DHCA) combined with retrograde cerebral perfusion (RCP) through the superior vena cava (n = 50) and simple DHCA (n = 15) were used during the procedure. Blood samples for lactic acid level from the jugular vein were compared in both groups at different phase, and perfusion blood distribution and oxygen content difference between the perfused and returned blood were measured in some RCP patients. RESULTS: The DHCA time was 35.9 +/- 18.8 min (10.0 - 63.0 min) and DHCA + RCP time was 45.5 +/- 17.2 min (16.0 - 81.0 min). The resuscitation time was 7.1 +/- 1.6 h (4.4 - 9.4 h) in DHCA patients and 5.4 +/- 2.2 h (2.0 - 9.0 h) in RCP patients. Operation death was 3/15 in the DHCA group and 1/50 in the RCP patients. Central nervous complication existed in 3/12 of DHCA patients and 1/49 of RCP patients (P < 0.01). The overall survival rate was 96% (RCP) vs 67% (DHCA), central nervous system dysfunction was 20% in DHCA vs 2% in RCP (P < 0.01). The blood lactic acid level increased significantly after reperfusion in DHCA than in RCP. The blood distribution measurement approximated to 20% of the perfused blood returned from arch vessels. Oxygen content between perfused and returned blood showed that oxygen uptake was adequate in the RCP group. CONCLUSIONS: The application of RCP could prolong the safety duration of circulation arrest. Cerebral perfusion may reep the brain cool and flush out particulate and air embolism. Open anastomosis of the aortic arch to the prosthesis can be safely performed. RCP is acceptable for brain protection in clinical practice.

Adult↗

PubMed2003

[Long-term effects of 17 beta-estradiol in promoting 45Ca uptake and mineralized bone-like tissue formation in human osteoblast-like cell lines TE85].

AIM: To study the long-term effects of 17 beta-estradiol (E2) on cell proliferation, 45Ca up-take, and mineralized bone-like tissue formation in human osteoblast-like cell line TE85. METHODS: Human osteoblast-like cell line TE85 was used as osteoblast cell model. Using methods of 3H-thymidine incorporation for cell proliferation and 45Ca deposit for calcium uptake, and Alizarin red S dye for mineralized bone-like tissue. RESULTS: Compared with the cells of control group, 3H-thymidine incorporation into TE85 cells was significantly increased (85.65%, 93.42% and 106.58%, respectively) and 45Ca uptake was increased (101.35%, 130.9% and 169.5% respectively), after treated with E2 (0.1, 1.0, 10 nmol.L-1) for 14 days. The stained area of Alizarin red S in E2 treated cells was also increased obviously. ICI182,780, a specific antagonist of estrogen receptor, was shown to partly inhibit E2 induced actions with the inhibition ratio of 19.6% or 37.28% in both experiments of 3H-TdR and 45Ca uptake on the condition of E2 (1.0 nmol.L-1). CONCLUSION: E2 was found to increase the mineralized bone-like tissue by enhancement of cell proliferation and promotion of calcium uptake, which were in favor of bone formation. These actions may be partly mediated by estrogen receptor.

Bone Density↗

PubMed2003

[Formation of blood resin in abiotic Dracaena cochinchinensis inoculated with Fusarium 9568D].

Fusarium 9568D, which belongs to Fusarium moniliforme, was isolated from the roots of Dracaena cochinchinensis in the suburb of Monglian, Yunnan Province of China. High activities of beta-glucosidase and cellulase were detected in the broth of Fusarium 9568D. The strain was inoculated in abiotic branch and wood of Dracaena cochinchinensis. After 4-5 months of culture, red resin emerged in the inoculated points. UV-IR spectrum analysis and antibiotic assay demonstrated that this resin almost resembled the natural blood resin.

Dracaena↗

PubMed2003

[Study of acute physiology and chronic health evaluation III and multiple organ dysfunction syndrome score in evaluating severity of intensive care units patient].

OBJECTIVE: To evaluate the value of acute physiology and chronic health evaluation(APACHE)III and multiple organ dysfunction syndrome(MODS) score introduced to evaluate the severity of intensive care unit(ICU) patient. METHODS: Seventy of ICU patients were scored by APACHE III and MODS scoring system respectively after admission for 24 hours. Area under of the receiver operating characteristic curve(ROC) was used to scale the ability of APACHE III and MODS scoring systems evaluating severity and predicting outcomes of ICU patient. The areas were compared among APACHE III, MODS and the score of APACHE III adding MODS. Discriminant was built between the scores and outcomes of patient, and coefficients were compared among the three scoring systems. RESULTS: The areas under of the ROC of APACHE III, MODS and the score of APACHE III adding MODS were 0.765, 0.643 and 0.753 respectively; coefficients of discriminant of them were 0.998, 0.892 and 0.568 respectively. CONCLUSION: APACHE III is superior to MODS scoring system in evaluating severity of ICU patient, and APACHE III add MODS score can't increase the evaluating effectiveness compared to APACHE III and MODS score respectively in evaluating severity of ICU patient.

APACHE↗