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Biomedical subjects

G Zhang

Publications and source records attributed to G Zhang.

At least 523 records · Page 29Linked to original sources
PubMed1996

Tolerance of hypothalamic beta-endorphin neurons to mu-opioid receptor activation after chronic morphine.

The mu-opioid receptor is an autoreceptor on hypothalamic beta-endorphin neurons that when activated inhibits cell firing via increasing an inwardly rectifying potassium conductance. The membrane hyperpolarization to DAMGO ([D-Ala2, N-Me-Phe4, Gly-ol5]-enkephalin) in beta-endorphin and other arcuate (ARC) neurons was investigated in hypothalamic slices from control and morphine-treated, ovariectomized guinea pigs. Chronic morphine treatment caused both a decreased potency (EC50 220 +/- 10 nM vs. 64 +/- 3 nM in controls) and a decreased efficacy (Vmax: -7.1 +/- 1.1 mV vs. -10.7 +/- 0.6 mV in controls) of DAMGO in a population of ARC neurons including beta-endorphin neurons. In another population of ARC neurons from morphine-treated animals, DAMGO was less potent (EC50: 110 +/- 4 nm) than in controls (EC50: 64 +/- 3nM), but there was not a significant change in the efficacy of DAMGO. Twenty percent of ARC neurons did not exhibit any signs of tolerance. The density of mu-opioid receptors labeled with the antagonist radioligand [3H]diprenorphine was found to be significantly decreased in the ARC and surrounding mediobasal hypothalamus after morphine treatment (Bmax: 217 +/- 9 vs. 276 +/- 16 fmol/mg protein in controls), which is consistent with the altered response in beta-endorphin neurons. In summary, chronic morphine treatment decreases mu-opioid receptor density and the functional coupling of mu-opioid receptors to K+ channels in ARC neurons. This expression of morphine tolerance by beta-endorphin (ARC) neurons may serve as a homeostatic mechanism to maintain opioid control of a variety of systems ranging from reproduction to motivation and reward.

Analgesics, Opioid↗
PubMed1996

The effect of rhubarb extract on experimental renal fibrosis.

In order to explore the therapeutic potential of traditional Chinese medicinal herbs on the progression of experimental chronic renal failure (CRF), we have studied the effect of orally administered rhubarb extract on the course of CRF in rats submitted to subtotal nephrectomy (SNx). Adult male Wistar rats were submitted to either a SNx (n = 18) or a sham operation (n = 10). Thirty days after SNx, nine SNx and five sham operated rats were given aqueous rhubarb roots extract (150 mg/day) in drinking water. The rats were followed up for 120 days. Rhubarb treatment had no effect on the systemic hypertension observed in SNx rats. Rhubarb-tested SNx rats had significantly less proteinuria 90 days (172 +/- 63 mg/24 h) and 120 days (228 +/- 92 mg/24 h) after SNx when compared to untreated SNx controls (day 90, 246 +/- 80 mg/24 h; day 120, 335 +/- 113 mg/24 h, P < 0.05). Renal function was comparable in rhubarb-treated and untreated SNx rats. However, at sacrifice the severity of glomerulosclerosis was significantly reduced in SNx rats treated with rhubarb (2.03 +/- 0.44; SNx controls, 2.58 +/- 0.53, P < 0.05). The difference in tubulointerstitial scarring between the two groups did not reach significance. Our results suggest that rhubarb extract reduces proteinuria and the severity of glomerulosclerosis in rats with remnant kidneys.

Animals↗
PubMed1996

[Value of cancer-related oncoprotein expression as prognostic factors in breast-cancer with one to three axillary lymph nodes positive].

The patient group with breast carcinoma with one to three axillary lymph-node metastases (n1-3) shows a poorer prognosis than the node-negative one but a better prognosis than the group with 4 or more lymph node metastases. Univariate analysis shows that loss of bc1-2 expression, nuclear accumulation of p53, overexpression of c-erbB-2, age at diagnosis, menstrual status, tumor size, histologic grade, number of lymph nodes involved, and estrogen receptor were all significantly associated with the survival rates. Multivariate analysis demonstrated that menstrual status, number of involved lymph nodes, bc1-2, and p53 were significant predictors for overall survival, and that histological grade and number of nodes involved were significant predictors for disease-free survival. Combination of those factors would be useful to select highly aggressive n1-3 breast cancer group.

Axilla↗
PubMed1996

[Canonical correlation of body composition and pulmonary function in children aged eight to twelve].

Canonical correlation of body composition and pulmonary ventilation function in school boys and girls aged 8 to 12 and normally developed was analyzed. Skinfolds of triceps and subscapular angle were measured, and body composition was estimated as body fat percentage (BF%), body fat (BF) and lean body mass (LBM). Ventilation function was measured. Results indicated that correlation between body composition and ventilation function mainly attributed to a positive correlation between LBM and vital capacity (VC) and a negative correlation between BF% and a ratio of expiratory reserve volume (ERV) to VC. It suggests effects of body composition on ventilation function mainly attributed to LBM and BF%.

Body Composition↗
PubMed1996

Naked DNA delivered intraportally expresses efficiently in hepatocytes.

Naked plasmid DNA in hypertonic solutions was injected intraportally in mice whose hepatic veins were transiently occluded. High levels of luciferase expression and beta-galactosidase expression in 1% of the hepatocytes throughout the entire liver were achieved using 100 micrograms of the respective plasmid vector. Two days after the intraportal injection of 100 micrograms of pCMVGH, the mean hGH serum concentration was 65 ng/ml +/- 26 (n = 7) which is approximately 50-fold above normal baseline levels. These unprecedented levels of foreign gene expression from naked plasmid DNA document the ability of parenchymal cells in vivo to take up naked DNA following intravascular delivery.

Animals↗
PubMed1996

[Immunostaining of anti-Bcl-2 antibody in diseased human muscles].

Immunostaining of Bcl-2 protein which represses apoptosis was performed on 178 biopsied human pathologic muscles and 10 control muscles by the ABC method using two monoclonal anti-Bcl-2 antibodies. Bcl-2 in control muscles was positive mainly in nuclear membrane and cytoplasm in type 2 fibers (especially type 2B fibers), and negative in type 1 fibers. In myopathies, it was not expressed in type 2C (regenerating) fibers, and its expression in atrophic fibers such as forming pyknotic nuclear clumps was strong. In inflammatory myopathies, expression was observed in infiltrating lymphocytes, and especially in dermatomyositis in atrophic fibers facing perimysium. In mitochondrial myopathies, the positivity was observed only in type 2 ragged-red fibers. In muscles of neurogenic disorders, both small angulated fibers and atrophic grouped fibers were strongly positive. Western blot analysis using anti-Bcl-2 antibody showed a single band at 26 kDa in control and diseased skeletal muscles. Compared to immunostaining of Fas antigen in serial sections, both Bcl-2 and Fas were expressed in same atrophic fibers in distal myopathy with rimmed vacuoles. In myotonic dystrophy, they were often expressed in type 2 fibers containing internal nucleus. In carriers of Duchenne dystrophy, Fas-positive but Bcl-2 negative fibers were observed in same dystrophin-negative fibers. In conclusion, expression of Bcl-2 in skeletal muscles might suggest that Bcl-2 plays a role on surviving muscle fibers.

Apoptosis↗
PubMed1996

[Influence factors in etiology of epithelial ovarian cancer].

OBJECTIVE: To investigate the role of genetic and psychosomatic factors in the development of epithelial ovarian cancer. METHODS: A hospital-based case-control study was conducted in 9 hospitals of Shandong province. 127 cases of epithelial ovarian cancer and 254 cases of non-malignant ovarian tumors were admitted for treatment during the same period of time. Data for single predictors and multivariants collected from hospital records were subjected to non-condition multivariate logistic analysis, in order to sort the protective factors and the high risk factors in the development of epithelial ovarian cancer. RESULTS: Adverse events in life, blood type A, mental depression or anger, family history of ovarian cancer and irregularity of bowel movements are the high risk factors. An open and cheerful disposition or optimism, hysterectomy with preservation of one or both ovaries and intrauterine device were shown to be the protective factors for the ovaries. CONCLUSION: Genetic and psychosomatic factors play an important role in the course of development of epithelial ovarian cancer.

Adolescent↗
PubMed1996

Exercise echocardiography: feasibility and value for detection of coronary artery disease.

OBJECTIVE: To evaluate the feasibility and accuracy of exercise echocardiography (Ex-Echo) for the diagnosis of coronary artery disease (CAD) based on coronary angiography (CA). PATIENTS AND METHODS: Forty-seven patients were found to have CAD and examined by upright exercise electrocardiography (Ex-ECG) on a treadmill within two weeks of CA. Before and immediately after exercise, the patients lay on a bed beside the treadmill in the left lateral position and parasternal long and short axis and apical two and four chamber views of the heart were acquired. Pre- and post-echocardiograms were analysed in a side-by-side multiple screen format on the imaging view and hypodynamic wall motion of the left ventricle after exercise was defined as Ex-Echo positive. The sensitivity, specificity and predictive accuracy of Ex-Echo and Ex-ECG were calculated on the basis of CA data. RESULTS: Satisfactory echocardiograms were recorded in 46 patients after exercise. The success rate was 97.8%. Compared with Ex-ECG, Ex-Echo was more sensitive (87.5% vs 62.5%, P < 0.05), specific (92.8% vs 60.0%, P < 0.05) and accurate (89.4% vs 61.7%, P < 0.01). The concord of determining the number of diseased vessels between coronary angiography and Ex-Echo was 90.9% in single vessel disease and 45.0% in multiple vessel disease. Wall motion scoring index, however, was higher in multiple than in single vessel CAD. CONCLUSIONS: Ex-Echo test is feasible and accurate in detecting CAD and wall motion scoring index is probably useful in distinguishing multiple from single vessel CAD.

Coronary Disease↗
PubMed1996

[An antisense oligodeoxynucleotides for NR1 suppressed seizures and reduced discharges in the temporal cortex slice in genetically epilepsy-prone rat].

OBJECTIVE: To investigate the effects of N-methyl-D-aspartate receptors (NMDAR or NR) and NR1 subunit on mechanism of initiation and development epilepsy of genetically epilepsy-prone rat. METHODS: Antisense oligodeoxynucleotices (ODN) techniques, intracerebroventricular injection and experiments in vitro in rat temporal cortex slices were used. RESULTS: An antisense ODN for NR1, or the correspond sense ODN and normal saline was administered intracerebroventricular (i.c.v., 100 micrograms in 10 microliters) once daily, respectively for three days. P77PMC rats with antisense ODN did not display clonic and tonic convulsion, or showed that significantly lowered seizure scores compared to control groups. Moreover, the frequency and amplitude of early seizure-like events (SLEs) and late reccurrent discharges (LRDs), which induced by lowing Mg2+, were reduced in entorhinal cortex of the temporal cortex slice. CONCLUSION: Our results suggested that NMDA receptors, specifically the NR1 subunit, may participate in the initiation and development of epilepsy of P77PMC rat.

Animals↗
PubMed1996

Prevention of disability and rehabilitation--results from a collaborative project in China.

Eight different geographical districts in China varying in urban and rural characteristics from 6 provinces and 2 municipalities were selected as pilot areas of the project. The interventions included early detection and treatment of neuritis, self-care training, adapted footwear, surgery, comprehensive treatment of complicated ulcers, and prostheses. Main changes in eye, hand and foot impairments between baseline assessment and assessment at 2 years have been presented in this paper.

China↗
PubMed1996

[Effects of rotating stimuli on electronystagmogram and electrogastrogram in guinea pigs].

The purpose of this study is to investigate the effects of repeated rotating stimuli on electronystagmogram (ENG) and electrogastrogram (EGG) in guinea pigs. ENG and EGG were separately recorded prior to the stimuli and on the next day and 30 days after repeated stimuli in 14 guinea pigs with normal pinna reflexes. The results showed that the numbers of the bilateral vestibular nystagmus (L and R separately represented the numbers of left and right nystagmus) of postrotation (L = 682, R = 657) were obviously less than that of prerotation (L = 857, R = 842) (P < 0.01, pairing t-test), and EGG amplitude of postrotation (4506 microV) during the whole course of rotating stimuli was lower than that of prerotation (5279 microV) (P < 0.01, pairing t-test). The numbers of bilateral nystagmus (L = 845, R = 826) were obviously raised again 30 days after stopping rotating stimuli (P < 0.01, compared with next day after stopping repeated stimuli; P > 0.05 compared with before rotating stimuli). It was concluded that repeated rotating stimuli can decrease the vestibulo-ocular and vestibulo autonomic reflexes in guinea pigs, but the effects were not timeless.

Animals↗
PubMed1996

[Extraovarian peritoneal serous papillary carcinoma: a clinicopathologic analysis of 11 cases].

OBJECTIVE: To investigate the clinical features, diagnostic criteria, treatment methods and prognosis of extraovarian peritoneal serous papillary carcinoma (EPSPC). METHOD: Eleven cases histologically confirmed as EPSPC and treated in our hospital from Jan. 1989 to May, 1994 were retrospectively analysed. RESULT: All patients with EPSPC were given cytoreductive surgery followed by systemic chemotherapy of PAC (carboplatin, Adriamycin, cyclophosphamide) regimen. The interval between chemotherapeutic treatments was one month, and the whole course of chemotherapy lasted at least 2-3 years. All patients except 3 were followed up, and the mean survival time reached 17.1 months. CONCLUSION: Due attention should be paid to differential diagnosis of EPSPC. The prognosis may be improved by cytoreductive surgery and chemotherapy of the PAC regimen.

Cystadenocarcinoma, Papillary↗
PubMed1996

[Late result of valve replacement with giant heart].

212 cases of valve replacement with giant heart were followed up for 0.2-15.7 years (mean 3.23 years). There were 21 late deaths. The total survival rate was 91.3%, 80.6%, 74.3% at the 3rd, 6th and 9th year after operation, respectively, and the symptomatic remission rate was 84.4%, 70.6%, 56.8%, respectively. In patients with left atrium and right cardiac enlargement, the survival rate and symptomatic remission rate was significantly higher than those of left ventricle and total cardiac enlargement. The factors influencing late surgical result was discussed.

Adolescent↗