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Biomedical subjects

Gang Cheng

Publications and source records attributed to Gang Cheng.

83 records · Page 5Linked to original sources
PubMed2002

A putative silencer element in the IL-5 gene recognized by Bcl6.

The Bcl6 gene is ubiquitously expressed in adult murine tissues and its product functions as a sequence-specific transcriptional repressor. Bcl6-deficient mice displayed eosinophilic inflammation caused by overproduction of Th2 cytokines. The regulatory mechanism of those cytokine productions by Bcl6 is controversial. When CD4(+) T cells from Bcl6-deficient and lck-Bcl6-transgenic mice were stimulated with anti-CD3 Abs, production of IL-5 among Th2 type cytokines was preferentially affected by the amount of Bcl6 in the T cells. We found a putative Bcl6-binding sequence (IL5BS) on the 3' untranslated region in the murine and human IL-5 genes, and specific binding of Bcl6 protein to the sequence was confirmed by gel retardation assay and chromatin immunoprecipitation assay. The binding activity of endogenous Bcl6 was transiently diminished in Th2 but not in Th1 clones after anti-CD3 stimulation. The exogenous Bcl6 repressed expression of the reporter gene with the IL5BS in K562 cells and the repressor activity was lost by a point mutation of the IL5BS. Furthermore, the IL5BS was required for Bcl6 to repress expression of the IL-5 cDNA. Thus, the IL5BS may act as a silencer element for Bcl6 to repress expression of the IL-5 gene.

3T3 Cells↗
PubMed2002

Spatiotemporal and tissue specific distribution of apoptosis in the developing chick heart.

To investigate spatial and temporal distributions of apoptosis in the embryonic chick heart and its relation to different tissue types, we examined apoptosis in the embryonic chick heart from Hamburger and Hamilton stage 17 through 3 days after hatching. MF20 antibody, alpha-smooth muscle actin (SMA) antibody and EAP-300 antibody were applied to delineate specific cell types. During early development of the embryonic chick heart, very few apoptotic cells were detected. The first distinctive zone of apoptosis was observed in the outflow tract at stage 25. This focus was most prominent during septation of the pulmonary artery from the aorta (i.e., between stages 28 and 29), and diminished to virtually background level by stage 32, except in the subconal regions. Subsequently, remarkable apoptosis appeared in the atrioventricular cushions by stage 26, peaked at stages 29-31, and dropped significantly thereafter. Characteristic distribution patterns of apoptotic cells were also detected in the cardiac conduction tissues, including the His bundle, the bundle branches, and the ventricular trabeculae. After stage 36, cell death dropped to background level, except in developing coronary vessels. MF20 and TUNEL double staining revealed that apoptosis in cardiomyocytes was limited to a few specific regions, much less than in cushion tissues. SMA and TUNEL double staining demonstrated that vascular structures were the major foci of apoptosis from stage 40 to 44, whereas adjacent perivascular Purkinje cells displayed significantly less cell death at these stages. The characteristic spatiotemporal locations of apoptosis parallel the morphologic changes and tissue differentiation during heart development, suggesting that apoptosis is crucial to the transformation of the heart from a simple tube to a complex multichambered pump.

Actins↗
PubMed2002

Hepatitis B and C viruses infection, lifestyle and genetic polymorphisms as risk factors for hepatocellular carcinoma in Haimen, China.

A case-control study was carried out to investigate the impact of factors including virus infection, aflatoxin B1, microcystins, smoking/drinking and dietary habits as well as genetic polymorphisms of aldehyde dehydrogenase 2 (ALDH2) and cytochrome P4502E1 (CYP2E1), on susceptibility to hepatocellular carcinoma (HCC) in Haimen, China. A total of 248 patients with HCC and 248 sex-, age- and residence-matched population-based controls were recruited into the study. Virus infection, and ALDH2 and CYP2E1 gene polymorphisms were assessed in 134 paired cases and controls. By univariate analysis, hepatitis B virus (HBV) infection (odds ratio [OR]=9.75; 95% confidence interval [CI]=4.71-20.2), history of intravenous injection (OR=1.50; 95%CI=1.02-2.22), average income (OR=0.63; 95%CI=0.43-0.92), frequent intake of foods rich in protein, e.g., egg (OR=0.6; 95%CI=0.42-0.87), chicken (OR=0.53; 95%CI=0.35-0.79), pork (OR=0.67; 95%CI=0.46-0.98) and fresh fish (OR=0.58; 95%CI=0.39-0.87) significantly differed between cases and controls. However, peanut intake (OR=0.66; 95%CI=0.43-1.01), source of drinking water, including tap (OR=1.33; 95%CI=0.81-2.20), deep well (OR=0.94; 95%CI=0.56-1.55), shallow well (OR=0.85; 95%CI=0.55=1.30), river (OR=0.95; 95%CI=0.65-1.38), ditch (OR=1.09; 95%CI=0.76-1.55) and pond water (OR=1.0; 95%CI=0.14-7.10) were not significantly associated with risk. Univariate analysis also indicated that the 1-1 genotype of ALDH2 (OR=1.38; 95%CI=0.86-2.23) as well as the Pst1- and Rsa1-digested c1/c1 genotype of CYP2E1 (OR=1.36; 95%CI=0.81-2.28), was slightly more frequent in the case group. On multivariate analysis, HBV infection (OR=13.9; 95%CI=5.78-33.6) and history of intravenous injection (OR=2.72; 95%CI=1.24-6.00) were still associated with significantly increased risk of HCC, while frequent intake of fresh fish (OR=0.32; 95%CI=0.12-0.86) decreased this risk. These findings suggest that whereas peanut intake, water sources as well as genetic polymorphisms in ALDH2 and CYP2E1 do not significantly correlate with the risk of HCC, HBV infection is a main risk factor, and dietary items rich in protein, especially fresh fish, might protect against the risk of HCC in Haimen, China.

Adult↗
PubMed2002

[Simvastatin induced apoptosis and its effect on apoptosis-related gene expression in rat vascular smooth muscle cell]

OBJECTIVE: To observe the influence of simvastatin on the apoptosis of vascular smooth muscle cells (VSMC) and its effects on the expression of apoptosis-related genes. METHODS: The presence of apoptosis was detected by electron microscope and flow cytometry assessment of PI/Annexin V stain; The protein levels of Bax, Bel-2 and activation of caspase-3 were examined using Western blot technique. RESULTS: After treatment with 30 &mgr;mol/L simvastatin for 24 h, apoptosis were identified with electron microscope in VSMC and flow cytometry showed that rate of apoptosis in simvastatin group (35.5+/-5.8)% was singificantly higher than that in control group (15.1+/-5.0)%. Western blot analyses revealed that the apoptosis process was associated with upregulation of Bax protein and activation of caspase-3, but not with Bel-2 expression. CONCLUSION: Simvastatin can induce apoptosis in VSMC in associated with induction of bax and activation of caspase-3.

Journal Article↗
PubMed2002

Development and clinical trial of fluorescence PCR diagnostic kit to detect Mycobacterium tuberculosis.

OBJECTIVE: To develop a new diagnostic kit for Mycobacterium tuberculosis (TB) detection on the basis of fluorescence PCR (F-PCR) and conduct clinical trial of this kit for assessing its performance in comparison with other diagnostic methods. METHODS: We collected 546 clinical sputum samples from patients with phthisis and normal subjects to examine TB by way of F-PCR in parallel with examination with modified R.culture, auramine smear with fluorescence staining and LCx DNA diagnostic kit from Abbott for comparison. RESULTS: A clinical diagnostic kit for TB detection was developed with F-PCR, and clinical trial showed that its positivity rate was 49.1%, sensitivity 89.2%, specificity 98.8% and efficiency 93.6%. CONCLUSION: F-PCR is obviously superior to culture method and smear method and comparable with LCx in terms of sensitivity, and can be used to monitor TB DNA in the secretions to facilitate clinical diagnose and therapeutic effects monitoring.

DNA, Bacterial↗
PubMed2002

[Study of immunological indicators in peripheral blood for nasopharyngeal carcinoma].

OBJECTIVE: To find reliable diagnostic immunological indicators in peripheral blood for nasopharyngeal carcinoma, and to evaluate the possibility of cancer screening and early diagnosis of the malignancies in the future. METHODS: Plasma samples were obtained from 83 patients with nasopharyngeal carcinoma and from 105 patients with benign diseases. Nine cytokines were selected as the candidates for the indicators and their quantity in the plasma samples determined by enzyme-linked immunosorbent assay, the result of which was analyzed statistically. RESULTS: Interleukin (IL)-4 level was obviously increased, while IL-6, IL-12, transforming growth factor (TGF)-beta, interferon (IFN)-gamma levels significantly reduced (P<0.05) in the plasma from patients with nasopharyngeal carcinoma. CONCLUSION: These cytokins may serve as the indicators in the diagnosis of nasopharyngeal carcinoma.

Biomarkers, Tumor↗
PubMed2002

[Nausea disintegrating buccal tablet in the prevention of gastrointestinal reaction induced by anticancer drugs].

OBJECTIVE: To evaluate the efficacy and safety of nausea oral, disintegrating buccal tablet (DBT) in the prevention of gastrointestinal reaction induced by anticancer drugs (cisplatin DDP 30 - 50 mg/m(2) or adramycin ADM >/= 40 mg/m(2)), as compared with those of kytril tablets. METHODS: A multicenter, open and randomized self-crossover control trial was carried out with all the eligible patients randomized into AB or BA group. Patients in AB group were given nausea 0.1 mg as buccal tablet one hour before chemotherapy in the first cycle and kytril tablet 2 mg in the second cycle, those in BA group were given these drugs in the reverse order. RESULTS: Seventy-three patients were allotted to this study, including 44 patients in DDP-arm and 29 in ADM-arm. Sixty-two patients were evaluable for response and 70 patients for safety. Nausea DBT was as effective as kytril tablet in the control of anorexia, nausea and vomiting during the first 24 hours after chemotherapy, with response rates of 74.2%, 77.4%, 83.9% in nausea DBT and 74.2%, 71.0%, 88.7% DBT in kytril tablets. A high efficacy in the control of vommitting induced by cisplatin was observed in both nausea DBT and kytril tablets. The complete control rates and overall control rates were 83.3%, 91.7% in nausea DBT and 86.1%, 97.2% in kytril tablets, respectively. The side effects of nausea DBT were head heaviness, dry mouth and somnolence, which were mild and comparable with kytril in their frequencies. CONCLUSION: Nausea disintegrating buccal tablet is able to effectively prevent gastrointestinal reaction induced by anticancer drugs, with efficacy and side effects similar to kytril tablets. Nausea DB tablet, an intraoral disintegrator, is very convenient for patients who can not swallow tablets for various reasons.

Adolescent↗
PubMedDate not supplied

Provision and financial burden of TB services in a financially decentralized system: a case study from Shandong, China.

Both challenges and opportunities have been created by health sector reforms for TB control programmes in developing countries. China has initiated radical economic and health reforms since the late 1970s and is among the highest TB endemic countries in the world. This paper examines the operation of TB control programmes in a decentralized financial system. A case study was conducted in four counties of Shandong Province and data were collected from document reviews, and key informant and TB patient interviews. The main findings include: direct government support to TB control weakened in poorer counties after its decentralization to township and county governments; DOTS programmes in poorer counties was not implemented as well as in more affluent ones; and TB patients, especially the low-income patients, suffered heavy financial burdens. Financial decentralization negatively affects the public health programmes and may have contributed to the more rapid increase in the number of TB cases seen over the past decade in the poorer areas of China compared with the richer ones. Establishing a financial transfer system at central and provincial levels, correcting financial incentives for health providers, and initiating pro-poor projects for the TB patients, are recommended.

China↗
PubMedDate not supplied

Hepatocellular ultrastructure after ischemia/reperfusion injury in human orthotopic liver transplantation.

The number of patients requiring organ transplants still outpaces the number of available transplantable organs. During the process of orthotopic liver transplantation (OLTx), donor organs undergo significant stress resulting from ischemia and reperfusion. Healthy organs respond to this stressful environment with compensatory mechanisms that ideally allow for complete recovery. However, "marginal" organs do not compensate as well. Hepatic steatosis typically renders an organ nontransplantable; a liver with 30% or more fat has a 25% chance of primary nonfunction (PNF) or graft failure after a technically sound operation. In this study, we report on the significant markers of cellular ultrastructural change in steatotic livers. These include glycogen content, mitochondrial swelling, and hepatocellular blebbing. The data disclosed here argue that further investigation of these factors in marginal organs subjected to I/R may better facilitate our understanding of PNF.

Analysis of Variance↗
PubMedDate not supplied

Comparison of Epstein-Barr virus DNA level in plasma, peripheral blood cell and tumor tissue in nasopharyngeal carcinoma.

BACKGROUND: The plasma Epstein-Barr virus DNA (EBV-DNA) level has been found to be an indicator for staging and prognosis of nasopharyngeal carcinoma (NPC). MATERIALS AND METHODS: The EBV-DNA level in plasma, peripheral blood cells (PBC) and neoplastic tissues was quantitatively analyzed and potential associations with clinical parameters of NPC were investigated. RESULTS: The plasma EBV-DNA detecting rate and level in NPC (92%, 82,500 copies/ml) was significantly higher than that in NPC after treatment (19%, 0 copy/ml) and in controls (12%, 0 copy/ml) (p < 0.001); while there was no significance of the PBC EBV-DNA detecting rate and EBV-DNA load in NPC before (24%, 0 copy/actin) and after treatment (14%, 0 copy/actin), and in controls (16%, 0 copy/actin). The plasma EBV-DNA level was not correlated to the PBC EBV-DNA load in NPC before (p = 0.92) and after treatment (p = 0.267), and in controls (p = 0.735). The EBV-DNA level in NPC tumor (27.8 copies/actin) was significantly higher than that in nasopharyngitis and was positively correlated to the ratio of EBER1-positive cells on the NPC section (p = 0.001). The plasma EBV-DNA level was significantly increased in TNM stages I, II, III and IV NPC, whereas there was no significant difference of PBC EBV-DNA load in different stage NPC. CONCLUSION: Our results indicate that plasma EBV-DNA is a more sensitive and reliable biomarker than PBC EBV-DNA for diagnosis, staging and therapeutic effect evaluation at a molecular level in NPC clinical practice. Plasma EBV-DNA may derive from the cancer cells and PBC EBV-DNA from circulating mononuclear cells in NPC patients.

DNA, Viral↗