Search PubMed⌕ Search

Biomedical subjects

Hong Zhang

Publications and source records attributed to Hong Zhang.

At least 235 records · Page 13Linked to original sources
PubMed2005

Synaptic fatigue is more pronounced in the APP/PS1 transgenic mouse model of Alzheimer's disease.

To search for potential mechanism that might alter synaptic transmission following Abeta increase we have examined the presynaptic component of transmitter release. As parameters of synaptic transmission that might underlie presynaptic mechanisms, we have used paired-pulse facilitation (PPF), post-tetanic potentiation (PTP), and synaptic fatigue (SF) at the connection between the hippocampal Schaffer-collateral pathway and CA1 pyramidal neurons in approximately 5 month old double transgenic mice overexpressing the mutated form of amyloid precursor protein (APPK670N, M671L) and presenilin 1 (PS1M146V). While the presynaptic mechanisms of PPF and PTP were not compromised in the APP/PS1 mice, SF was more pronounced in the double transgenic animals. The percentage of the 40th fEPSP slope over the first during the tetanus was 18 -/+ 3% in APP/PS1 vs. 26 -/+ 2% in WT. Thus, it is likely that presynaptic mechanisms underlying SF but not PPF and PTP, may account for synaptic dysfunction in APP/PS1 mice.

Alzheimer Disease↗
PubMed2005

[Expression and significance of cell cycle regulators in gastric carcinoma].

BACKGROUND & OBJECTIVE: Abnormality of cell cycle regulation is an important cause of cell over-proliferation and oncogenesis. But the relationship between cell cycle regulators and gastric carcinoma is uncertain. This study was to investigate the expression and significance of cell cycle regulators, including P16(INK4), Cyclin D1, P21(WAF1), and P53, in gastric carcinoma. METHODS: The expressions of P16(INK4), Cyclin D1, P21(WAF1), and P53 in 53 specimens of gastric carcinoma were observed by SP immunohistochemistry. Multivariate Cox regression was used to analyze factors affecting prognosis. RESULTS: Positive rate of P53 in gastric carcinoma was higher than that in adjacent tissues (60.4% vs. 0, P < 0.01); those in well, and poorly differentiated adenocarcinoma were significantly higher than that in mucoid carcinoma (65.4%, and 68.2% vs. 0, P < 0.01). Over-expression rate of Cyclin D1 in gastric carcinoma was higher than that in adjacent tissues (69.8% vs. 5.7%, P < 0.01). Positive rate of P16(INK4) in gastric carcinoma was lower than that in adjacent tissues (60.3% vs. 88.6%, P < 0.05). Positive rate of P21(WAF1) in gastric carcinoma was lower than that in adjacent tissues (26.4% vs. 56.6%, P < 0.01). Positive rate of P16(INK4) was significantly related with the depth of tumor invasion (P < 0.05), and lymph node metastasis (P < 0.01). Multivariate Cox regression analysis indicated that lymph node metastasis and the expression of P16(INK4) were independent prognostic factors of gastric carcinoma. CONCLUSIONS: Down-regulation of P16(INK4) and P21(WAF1), and over-expression of Cyclin D1 and P53 are significantly related to genesis and progression of gastric carcinoma. Down-regulation of P16(INK4) may be correlated to infiltration, metastasis, and prognosis of gastric carcinoma.

Adenocarcinoma↗
PubMed2005

[Effect of high-oxygen water on enhancing anoxia endurance and anti-fatigue function and the possible mechanism].

OBJECTIVE: To investigate the effect of high-oxygen water on anoxia endurance and anti-fatigue function in mice and explore the possible mechanism. METHODS: KM mice were used. Their body weight, serum urea nitrogen, hepatic glycogen, swimming-sustaining time of mice with a load, plasma lactic acid content, survival time under anoxia or sodium nitrite poisoning were measured. RESULTS: It was found that high-oxygen water can prolong swimming time and can protract the anoxia survival time of mice under normal pressure and being afflicted with acute cerebral ischemia (P<0.05). It can also decrease the level of serum urea nitrogen after exercise (P<0.05) and increase hepatic glycogen storage (P<0.05). CONCLUSION: The results demonstrate that high-oxygen water can enhance the emergent survival ability of mice, the ability of fatigue recovery and anoxia endurance function. It also can increase the energy storage.

Animals↗
PubMed2005

Optimal frequency of CD4 cell count and HIV RNA monitoring prior to initiation of antiretroviral therapy in HIV-infected patients.

CONTEXT: Guidelines regarding the frequency of CD4 cell count and HIV RNA monitoring in HIV-infected patients vary, with recommended strategies ranging from every 2 to every 6 months. OBJECTIVE: To determine optimal CD4 cell count and HIV RNA monitoring frequency in HIV-infected patients prior to antiretroviral therapy initiation. DESIGN: Cost-effectiveness (CE) analysis using an HIV simulation model incorporating CD4 cell count and HIV RNA as immunological and virological predictors of clinical outcomes. SETTING: Hypothetical clinical setting. PATIENTS: Simulated cohort based on initial clinical presentation of HIV-infected patients in the US. INTERVENTION: CD4 cell count and HIV RNA monitoring at frequencies ranging from every 2 to 24 months prior to antiretroviral initiation, as well as accelerated monitoring frequencies as CD4 cell counts approach a specified treatment threshold. OUTCOME MEASURES: Life expectancy, quality-adjusted life expectancy and costs. RESULTS: For patients presenting with median CD4 cell count 546/mm3 and median HIV RNA 4.8 log10 copies/ml, incremental CE ratios ranged from US$37800/quality-adjusted life year (QALY) gained for a constant testing frequency of every 18 months compared with every 24 months, to US$303300/QALY gained for a constant testing frequency of every 2 months compared with every 4 months when starting treatment at a CD4 cell count of 350/mm3. Monitoring every 12 months until a warning CD4 cell count threshold of 450/mm3 followed by every 3 months until 350/mm3 had an incremental CE ratio of US$74700/QALY gained. When starting antiretroviral therapy at CD4 cell count 200/mm3, monitoring every 12 months until 300/mm3 followed by every 2 months until treatment initiation yielded an incremental CE ratio of US$52200/QALY gained compared with the next best strategy. Increasing monitoring frequency as CD4 cell counts approached a treatment threshold yielded greater incremental clinical benefit for less cost than strategies using a constant frequency. CONCLUSIONS: Monitoring HIV-infected patients every 12 months until 100 CD4 cells/mm3 prior to a specified treatment threshold followed by more frequent monitoring every 2 or 3 months until antiretroviral therapy initiation is both more effective and cost-effective than the current standard of care.

Anti-HIV Agents↗
PubMed2005

[Observation and research on the electroporation of S-180 cell induced by electric pulse].

This is our first time report of S-180 cell handled with various voltages, capacity and pulse number. Many pores on the S-180 cell membrane can be observed under scanning electron microscope. By the stains of trypan blue, we have known the influence of electric parameters on the ratio of poration. The results show that the ratio of electroporation has positive correlation with the voltages and the pulse number while negative correlation with the capacity.

Animals↗
PubMed2005

Apoptosis and differentiation induced by staurosporine in granulosa tumor cells is coupled with activation of JNK and suppression of p38 MAPK.

We report here that staurosporine can induce apoptosis or differentiation of granulosa tumor cells depending on its dosage. In presence of staurosporine concentrations > 50 nM, apoptosis was triggered in human granulosa cell tumor cells COV434. In the presence of concentrations < 50 nM, the shape of the otherwise globular granulosa cells differentiated into a flattened epithelioid-like appearance. The process was associated by the induction of prostaglandin synthase-2 (PGS-2) and C/EBPbeta expression and by an increase in progesterone production in the supernatant culture medium. The observed effects of staurosporine were synergized by forskolin. With phosphorylation-specific Western blotting and protein kinase assays, it was demonstrated that staurosporine suppresses the phosphorylation of p38 and activates JNK. These results suggest that p38MAPK and JNK signal transduction pathways were involved in the regulation of granulosa cell differentiation by staurosporine. These results may indicate the usefulness of staurosporine or its analogs for the development of a future medical treatment of granulosa tumors.

Apoptosis↗
PubMed2005

Survivin protein in UVB induced apoptosis of melanoma cells and in melanoma progression.

A model system of cultivated melanoma cells and melanomas from patients were used in this study to clarify whether survivin protein was involved in UVB induced cell damage and in melanoma progression. The melanoma cells in culture were exposed to different doses of UVB and post-cultivated for various periods of time. Cell viability, apoptotic index and expression of survivin proteins were estimated. Expression of the survivin in normal tissue, nevi, primary and metastatic melanomas from the patients were also examined by immunohistochemistry. Results showed that UVB induced cell damage and apoptosis in melanoma cells. Primary and wt p53 cells were more sensitive than metastatic and mutant p53 melanoma cells. Expression of survivin protein was markedly decreased in the primary melanoma cells after exposure to UVB compared to the metastasis. The expression was markedly decreased in wt p53 melanoma cells, but not in the mutant p53 melanoma cells. Survivin protein was expressed in nevi, primary and metastatic melanomas. However, the normal tissues were not expressed in the survivin protein. Survivin plays an important role in UVB-induced apoptosis. Overexpression of survivin might be a biomarker for early diagnosis for melanoma.

Apoptosis↗
PubMed2005

[Experimental study of apoptosis and Fas antigen expression in craniocerebral trauma].

OBJECTIVE: To evaluate the change in Fas antigen expression and apoptosis of neurons, to provide an experimental evidence of loss of neurons in craniocerebral injury, and to provide experimental evidence for clarifying multi-approach of the lost neuron after damage. METHODS: Brain impact injury was reproduced in SD rat with a free falling impacting device. Using immunohistochemistry method the Fas protein expression was assessed and apoptotic cells were detected with electron microscopy. RESULTS: Apoptotic cells were found near the contused area, and Fas-positive cells appeared around the injured and hippocampus areas at about 4 hours, peaked at 24 hours after injury and then reduced in number. CONCLUSION: Apoptosis and necrosis are two forms of cell death in brain tissue following experimental brain contusion. Moreover, the results imply that the Fas-FasL pathway plays a pivotal role in the pathophysiology of post-traumatic neuronal apoptosis.

Animals↗
PubMed2005

The stability of insulin-loaded polybutylcyanoacrylate nanoparticles in an oily medium and the hypoglycemic effect in diabetic rats.

AIM: To study the stability of insulin-loaded polybutylcyanoacrylate nanoparticles (IPN) in an oily medium (soybean oil containing 0.5% (v/v) Tween-20 and 5% (v/v) Vitamin E) along with the hypoglycemic effect following their oral administration to streptozotocin (STZ) induced diabetic rats. METHODS: The stability of IPN in the process was appraised by measurement of the amount of undegraded insulin associated to nanoparticles, the average size and the span of IPN, as well as the release of insulin from IPN. IPN in an aqueous medium (containing 0.5% (v/v) Tween-20) at pH 2.0 was also investigated as control. RESULTS: The study showed that IPN in the oily medium was more stable than that in the aqueous medium over one year of storage in the dark at (25 +/- 2) degrees C and the in vitro stability of IPN in the oily medium against degradation by proteolytic enzymes was much better than that in the aqueous medium. The apparent bioavailability of an oral administration of IPN (50 u x kg(-1)) in the oily medium versus an (sc) injection of insulin (2 u x kg(-1)) was 22.4%, much higher than that of IPN in the aqueous medium (15.5%), based on decreased areas above curve (AAC) determination for the blood glucose depression from time zero to 144 h of a single oral administration of IPN to STZ-diabetic rats. CONCLUSION: IPN in soybean oil containing Tween-20 (0.5% v/v) and Vitamin E (5% v/v) could be considered as an effective and stable delivery system for oral insulin.

Administration, Oral↗
PubMed2005

[Design and field calculation of coil array for transcranial magnetic stimulation (TMS) based on genetic algorithm].

It is the intent of this paper to locate the activation point in Transcranial Magnetic Stimulation (TMS) efficiently. The schemes of coil array in torus shape is presented to get the electromagnetic field distribution with ideal focusing capability. Then an improved adaptive genetic algorithm (AGA) is applied to the optimization of both value and phase of the current infused in each coil. Based on the calculated results of the optimized current configurations, ideal focusing capability is drawn as contour lines and 3-D mesh charts of magnitude of both magnetic and electric field within the calculation area. It is shown that the coil array has good capability to establish focused shape of electromagnetic distribution. In addition, it is also demonstrated that the coil array has the capability to focus on two or more targets simultaneously.

Algorithms↗
PubMed2005

[Change of cardiac myocyte nuclear inositol 1,3,4,5-tetrakisphosphate receptor binding properties in rat with myocardial ischemic reperfusion].

OBJECTIVE: To observe the alteration of cardiac myocyte nuclear inositol 1,3,4,5-tetrakisphosphate receptor (IP(4)R) binding properties in rat subjected to myocardial ischemic reperfusion in order to further make it clear whether this change is involved in the molecule mechanism of cell apoptosis of rat with myocardial ischemic reperfusion. METHODS: Extracting of cardiac myocyte nucleus was accomplished by saccharose density gradient centrifugation method, the binding properties of nuclear IP(4)R in different conditions were detected by radioligand binding assay. Apoptosis index of myocardial cell was determined by using TUNEL assay. RESULTS: (1) Myocardial cell apoptosis index in rat heart underwent 30 min regional ischemia and 3 h reperfusion increased distinctly compared with that in control group (P < 0.01). (2) There were two IP(4) binding sites located to the nuclear envelope. (3) In ischemic reperfusion injury (IRI) group, Bmax from high affinity binding site of nuclear IP(4)R significantly increased compared with that in sham-operated group, whereas Bmax from low affinity binding site didn't change. Kd values of both sites were all significantly decreased by 63% and 55%, respectively. (4) Phosphorylation of nuclear IP(4)R by PKC increased markedly its binding ability both in IRI and control group (P < 0.05), which was more apparent in IRI group. (5) In sham-operated group, the binding ability of nuclear IP(4)R increased with increasing free calcium concentrations in cytoplasm, and the binding properties of IP(4)R in IRI group were also increased in the condition of calcium overloading. CONCLUSION: The increasing of binding properties of nuclear IP(4)R from ischemic reperfusion heart may be one of important mechanism involved in myocardial cell apoptosis, furthermore resulting in myocardial IRI.

Animals↗
PubMed2005

[Study of the relationship between cardiovascular risk factors and severity of coronary artery disease in patients underwent coronary angiography].

OBJECTIVE: To evaluate the correlation between multiple cardiovascular risk factors and the extent and severity of angiographic coronary artery disease (CAD) in patients underwent coronary angiography. METHODS: Nine hundred and twenty consecutive patients underwent coronary angiography were selected according to inclusion criteria. The extent and severity of angiographic CAD was diagnosed by: (1) whether or not CAD was diagnosed by angiography; (2) the number of diseased vessels; (3) The CAD Gensini cumulative index. Cardiovascular risk factors included were age, gender, hypertension, smoking status, type 2 diabetes mellitus, dyslipidemia, and high uric acid level. Analyses were achieved by univariate and multivariate analysis. RESULTS: (1) Logistic regression analysis showed that high low-density lipoprotein was a prominent predictor of the extent and severity of angiographic CAD (OR = 2.816, 95% CI 1.903 - 4.167, P = 0.001). (2) High low-density lipoprotein was the most important risk factor in men, whereas smoking and high uric acid were the most important risk factors in women. CONCLUSION: (1) It is very important to control risk factors in the intervention and prevention of CAD. (2) Distribution of risk factors and their severities vary in different genders, therefore the treatment of risk factors should be done differently.

Adult↗
PubMed2005

[The interleukin-6 level in exhaled breath condensate of patients with obstructive sleep apnea-hypopnea syndrome].

OBJECTIVE: To explore whether the airway inflammation marker in exhaled breath condensate is increased in obstructive sleep apnea-hypopnea syndrome (OSAHS). METHODS: Thirty-one patients with OSAHS (15 smokers and 16 non-smokers) and 10 healthy age-matched and weight-matched controls were included in the study. Exhaled breath condensate (EBC) was collected before and after sleep at the same night from both groups. Interleukin-6 (IL-6) in EBC was measured by a specific enzyme immunoassay. RESULTS: (1) There was no difference in the pre-sleep IL-6 level among OSAHS smoker group, OSAHS non-smoker group and the control subjects (F = 0.515, P > 0.05). Compared with the level of pre-sleep [(2.5 +/- 1.0) ng/L in OSAHS smoker, and (2.3 +/- 0.8) ng/L in OSAHS non-smoker], the post-sleep level of IL-6 was elevated significantly in EBC from OSAHS patients of non-smokers [(3.1 +/- 1.2) ng/L] and smokers [(3.7 +/- 1.9) ng/L, P < 0.05]. Nevertheless, IL-6 level from the control group showed a reverse change. IL-6 was decreased significantly [(2.0 +/- 0.8) ng/L in pre-sleep vs (2.7 +/- 1.0) ng/L in post-sleep] after sleep in this group. There was no difference in post-sleep IL-6 level between OSAHS smokers [(3.7 +/- 1.9) ng/L] and non-smokers [(3.1 +/- 1.2) ng/L, P > 0.05]. A significant higher IL-6 level was observed in both OSAHS smokers [(3.7 +/- 1.9) ng/L] and non-smokers [(3.1 +/- 1.2) ng/L] compared with the controlled group [(2.0 +/- 0.8) ng/L, P < 0.05]. IL-6 level in EBC was correlated positively with AHI (r = 0.441, P < 0.05), ODI(4) (r = 0.533, P < 0.05), and negatively with minimal oxygen saturation (r = -0.529, P < 0.05). CONCLUSIONS: These findings suggest that inflammation was characteristic in the airways of OSAHS patients. Nocturnal hypoxia could be responsible for this change. The levels of IL-6 in EBC are associated with the severity of OSAHS and may prove to be useful in monitoring of airway inflammation in OSAHS.

Adult↗
PubMed2005

[Mathematical model of cardiac action potential and its computer simulations].

Malignant arrhythmias and ventricular fibrillation are generally accepted as one of the major causes of death in cardiovascular diseases. Based on the H-H equations, the mathematical model of the cardiac cell action potential consists of the ion channels, pumps, exchangers and transporters that are closely connected with intra- and extra-cellular ion concentrations, the channel's conditions, nerve transductors and drugs. It can build the link between cell electrophysiology and clinical pathophysiology. By altering the cellular environments the computer simulating study on this kind of model can help us look into the electrophysiological changes of the cardiac tissue and even the whole heart and investigate the mechanisms of the cardiac arrhythmias as well. The components of the model and its computer simulating study are introduced in the paper.

Action Potentials↗
PubMed2005

Construction of human VEGF165 gene eukaryotic expression plasmid and its effect on proliferation of vascular endothelial cells.

BACKGROUND: After organ transplantation, rapid repair of injured vascular endothelial cell(VEC) is a key to prevent graft chronic dysfunction besides control of immunological rejection. Many studies have confirmed that vascular endothelial growth factor 165(VEGF165) could accelerate the repair of VEC injury, decrease thrombosis and thrombotic occlusion, and inhibit hyperplasia of the intima. This study was designed to construct eukaryotic expression plasmid pBudCE4.1/VEGF165, and observe its effect on the proliferation of VEC. METHODS: The VEGF165 gene cloned from human heart tissue by RT-PCR was cloned into eukaryotic expression plasmid pBudCE4.1. The recombinant expression plasmid pBudCE4.1/VEGF165 was identified by restriction enzyme ( Hind III and BamH I) digestion analysis, and was sequenced. The pBudCE4.1/VEGF165 was introduced into VEC through lipofection transfection. The VEGF165 mRNA expression by Northern blot and VEGF165 protein expression was detected by immunocytochemical staining. The effect of expression protein on VEC proliferation was detected by flow cytometry. RESULTS: The RT-PCR product of the VEGF165 gene was about 576 bp. Sequencing analysis revealed that the sequence of the amplified VEGF165 gene was identical with that in GenBank. Restrictive enzyme digestion analysis showed that recombinant expression plasmid pBudCE4.1/tVEGF165 had been constructed successfully. The expression of VEGF165 at mRNA and protein levels in the transformed VSMCs had been demonstrated by Northern blot and immunocytochemical staining respectively. The expressed product of VEGF165 could notably accelerate the proliferation of VECs. CONCLUSIONS: pBudCE4.1/VEGF165 is successfully constructed and is expressed in VECs. Expressed VEGF165 can accelerate the VEC proliferation. The present study has laid a foundation for potential use of VEGF165 gene transfection to prevent and treat vascular stenosis in the transplanted organ.

Base Sequence↗
PubMed2005

[Serum resistin and leptin in patients with chronic obstructive pulmonary disease and their relationship to nutritional state].

OBJECTIVE: To investigate the serum resistin and leptin levels, their relationship to nutritional state and the associated factors in patients with chronic obstructive pulmonary disease (COPD). METHODS: The serum resistin and leptin levels in 57 stable COPD patients and 31 healthy controls were measured by enzyme-linked immunosorbent assay (ELISA) and radio-immunoassay respectively. Correlated factors of serum resistin and leptin were analyzed. RESULTS: The serum resistin and leptin levels in COPD patients [(2.1 +/- 1.2), (0.65 +/- 0.41) microg/L] were significantly lower than those in the healthy controls [(3.6 +/- 2.3), (1.03 +/- 0.71) microg/L, all P < 0.01]. The serum resistin and leptin levels in patients with malnutrition [(1.7 +/- 0.7), (0.43 +/- 0.16) microg/L] were significantly lower than those in patients without malnutrition [(2.2 +/- 1.2), (0.73 +/- 0.48) microg/L, all P < 0.05]. The serum resistin level in the patients was correlated with the serum leptin level, forced expiratory volume in one second (FEV(1)), and FEV(1)/forced vital capacity (FVC) (r = 0.426 - 0.531, all P < 0.01). The serum leptin level in the patients was correlated with serum resistin, FEV(1)/FVC, body mass index (BMI), percentage of ideal body weight (IBW%), chest circumference and abdominal circumference (r = 0.371 - 0.580, all P < 0.01). CONCLUSION: The serum resistin and leptin levels in stable COPD patients were significantly lower, especially in patients with malnutrition.

Adult↗
PubMed2005

[Experimental study on xue-bao capsules against injury of radiation or cyclophosphamide in mice].

OBJECTIVE: To explore the effects of xue-bao capsules on injury of radio-or chemo-therapy in mice, in order to provide rationale behind clinical trials. METHOD: xue-xu (deficiency of blood) model in mice was induced by radiation or cyclophosphamide. Leucocyte (WBC), erythrocyte (RBC), hemoglobin (Hb) and platelet (Pt) in peripheral blood as well as CFU-E and CFU-Gm in bone marrow were counted. RESULT: CFU-E and CFU-Gm in normal mice were promoted by this drug. The reduction of WBC, RBC and Hb in peripheral blood as well as CFU-E and CFU-Gm in bone marrow owing to the 3.5 Gy of 60Co radiation were antagonized by the drug. It had also antagonized cyclophosphamide induced the reduction of WBC, RBC and Pt in peripheral blood. CONCLUSION: xue-bao capsules has the effects against the adverse reactions of radio-or-chemo-therapy.

Animals↗