The possible mechanism of insulin resistance of the adipose tissue after burn injury was studied.The binding activity of the insulin receptors,the insulin effects on insulin-sensitive phosphodiesterase(PDE)and the level of free fatty acid(FFA)and cAMP were observed for 4 d in the adipose tissue of the rats inflicted with 30% TBSA full thickness scalding. It was found that the maximal binding capacity of the insulin receptors was greatly decreased(P

Objective To explore the function and mechanism of Dihuang Yinzi (DHYZ) in promoting learning and memory and delaying brain aging. Methods The Wistar rats aged 20 months were randomly assigned to receive oral administration of 6, 12, 18 g?kg~ -1 ?d~ -1 DHYZ, or 2 ml/d normal saline (control) for 30 d (n=12 in each group), then space memory was detected with Morris Water Maze, and expression of synaptophysin (SYP) and extracellular regulated protein (ERK) were measured by immunohistochemistry and Western blotting. Results Rats administrated with DHYZ showed shorter mean escape latency (P

Objective　To study the effects of hypoxia and glutamic acid on the kinetic properties of NMDA receptor channel of the hypothalamic neurons in rats. Methods　Cell-attached mode patch clamp technique was employed to record the single channel current of the NMDA receptor. Results　The open probability of NMDA receptor channel was increased after acute hypoxia compared with that of normal state, the open time τ1,τ2 was changed from (0.33±0.10)ms，(4.36±0.26)ms to (0.93±0.22)ms，(7.64±0.72)ms, and the close time τ1,τ2 was from (18.03±3.50)ms，(171.50±19.10)ms to (3.42±1.02)ms，(19.39±3.07)ms. The mean open probability was changed from 0.12±0.05 in normal state to 0.66±0.36 in hypoxia state. Furthermore, glutamic acid can increase open time and open probability of NMDA receptor channel,decrease close time. Conclusion　The excitability and the open probability of NMDA receptor channel of hypothalamic neurons increased by hypoxia is related to glutamate.

Objective To assess the effect of smoking and body mass index(BMI) on lung cancer incidence density in male workers.Methods Risk factors of cardiovascular diseases in baseline were surveyed in 1974,1979 and 1980 for 5 137 men aged more than 18 years old from Beijing Capital Steel and Iron Company.Follow-up was carried out to 2001;all diseases were identified by uniform standard.Cox proportional hazards model was used to analyze the relationship between smoking,BMI and lung cancer.Results During mean follow-ups of 20.8 years,106 cases of lung cancer occurred.The crude incident rates of lung cancer were 102.2 cases per 100 000 person-years.After adjustment for age,BMI and other established risk factors,cigarettes consumption of greater than 20 cigarettes/day versus no smoking was associated with a relative risk of lung cancer of 3.45(95% confidence interval(CI): 1.58～7.53).In categories of BMI of less than 18.5(underweight),18.5～24.9(normal weight) and more than 25 kg/m2(overweight and obesity),adjusting for age and other covariables,all workers and smoking workers both showed decreasing tendencies in relative risks of lung cancer in higher BMI groups.The pattern was similar after excluding the early 5-year lung cancer patients.Grouping in smoking and BMI levels,compared with underweight smokers,the relative risks for lung cancer of normal-weight nonsmokers and nonsmokers with overweight and obesity,as well as smokers with overweight and obesity were 0.25(95% CI: 0.08～0.84),0.16(95% CI: 0.04～0.74) and 0.23(95% CI: 0.07～0.77),respectively.Smokers with underweight had higher risk for lung cancer.Conclusion Smoking and underweight increased the risk of lung cancer.Keeping normal weight and giving up tobacco were important for the prevention of lung cancer.

Objective To observe the expression and phosphorylation of N-methyl-D-aspartate (NMDA) receptor NR1 subunit in rat cortex and hippocampus under high altitude hypoxia. Methods The adult SD rats were exposed to hypobaric hypoxia imitating 5 500-meter high altitude for 8 h daily for 3, 7, 14, 21 d. Immunohistochemical staining, Western blotting and co-immunoprecipitation were used to detect the expression and phosphorylation of NR1 in rat cortex and hippocampus. Results Both immunohistochemistry and Western blotting showed NR1 expression in rat cortex and hippocampus was increased under hypoxia in a time-dependent manner. The tyrosine phosphorylation of hypoxia groups was increased, and reached the peak on day 14 after hypoxia, then decreased, still higher than that of control groups till day 21 (P

Objective To study the effect and the mechanism of astrocytes-derived estrogen on synaptic transmission. Methods Based on the model of pure cultures of neonatal cortical neurons, the experimental groups were designed as follows: pure neuron culture (group P), ACM culture (group A), mixed culture of AST and neuron (group M), E_ 2 culture (group E), ACM+tamoxifen (estrogen receptor antagonist) culture (group A+T ), tamoxifen culture (group T). The difference among these groups of synaptic transmission was recorded by patch clamp and presynaptic vesicle releasing kinetics was marked by a dye named FM4-64. Results The mean amplitude and frequency of miniature postsynaptic currents (mPSCs) of group P, A, M, E, A+T and T were: (20.5?2) pA, (13?4) min -1 ; (29.1?3) pA, (73?16) min -1 ; (31.3?3) pA, (78?20) min -1 ; (30.2?3) pA, (76?18) min -1 ; (24.5?2) pA, (35?10) min -1 ; (22.1?2) pA, (37?10) min -1 respectivily. The treatment of pure neuron culture with ACM increased synaptic transmission of pure cultured cortical neuron. Exogenic estradiol added into pure neurons can stimulate the effect of the ACM. Tamoxifen which was the antagonist of estrogen receptor could decrease most effect of ACM on synaptic transmission. The assaying of vesicle release marked by FM4-64 showed astrocytes-derived estrogenic enhancing synaptic transmission was at least mediated by strengthening presynaptic vesicle releasing. Conclusion The estrogen from astrocytes of neonatal rat cortex may enhance neuronal synaptic transmission mainly through estrogen receptor.

AIM:To observe the effect of altitude hypoxia on ?-aminobutyric (GABA) content and prepro-somatostatin mRNA (PPS-mRNA) in the rat hypothalamus. METHODS: Using altitude hypoxia model,in situ hybridization and amino acid analyzer, the number of PPS-mRNA and GABA content in rat hypothalamus was determined. RESULTS:After altitude hypoxia, the contents of GABA in hypothalamus and the number of PPS-mRNA neurons in periventricular nucleus (PeVN), paraventricular nucleus (PaVN) and arcuate nucleus (ArcN) increased significiantly. Bicuculline, a GABA receptor antagonits, could enhance PPS-mRNA expression evoked by altitude hypoxia, but had no effect on GABA content. CONCLUSION: Altitude hypoxia can induce neurotransmitter imbalance of hypothalamus.

Objective　 To study the prevalence and relevant risk factors of low blood pressure and its influence on cardiovascular diseases in China. Methods　A cross-sectional study for low blood pressure was conducted using the data of the third national survey of blood pressure in 1991. Low blood pressure was defined for systolic (SBP) and diastolic (DBP) pressure less than the tenth percentile for the sample (SBP≤98mmHg and DBP≤60mmHg). Results　The prevalence of low blood pressure for males and females were 2.7% and 7.4%, respectively. The prevalence of low blood pressure for females was higher than that of males (P<0.01). Prevalence of low blood pressure was 7.62%, 6.97%, 4.40%, 3.22%, 2.65%, 1.94% for age groups 15～, 25～, 35～, 45～, 55～, 65～, respectively. The prevalence of low blood pressure was gradually declined with aging. There was large variation in the prevalence of low blood pressure for different minorities. The prevalence of low blood pressure was higher in the southern rather than the northern part of China. Logistic regression showed that the age (OR 0.97, 95%CI 0.97～0.98, per 10 mmHg), BMI (OR 0.80, 95%CI 0.80～0.81), drinking (OR 0.89, 95%CI 0.86～0.93) and heart rate (OR 0.981, 95%CI 0.980～0.982) had reverse relationship with low blood pressure. The sex had a positive relationship with low blood pressure. The prevalence of stroke and myocardial infarction in the population with low blood pressure was lower than that of normal pressure or hypertension (P<0.01). Conclusion　The prevalence and relevant risk factors of low blood pressure in China were various. We speculate that low blood pressure in Chinese population appears to be a normal state of physiology.The difinite influence in health needs cohort studies to confirm.

Neurobiology is to study the structure,function,development and regeneration of the nervous system at molecular,cellular and whole level.The objective of neurobiological teaching is to explore the importont and difficult points in teaching' the present article attempts to design a project pattern in practical course of neurobiology,which is suited to learning mode of medical college students.

Objective To measure the estrogen concentration of estrogen (E 2) in the culture medium of rat astrocytes (ASTs). Methods Astrocytes in brain cortex of the 2-day-old neonatal rats were collected and cultured. The number of astrocytes was counted and the concentration of estrogen was measured by ELISA method at 0, 7, 14, and 21 d after culture. Results The cell counts were 1?10 4/ml, 1.1?10 6/ml, 1.4?10 6/ ml, and 1.5?10 6/ml, respectively. The concentrations of E 2 were: 0 pg/ml, (117.03?21.32) pg/ml, (266.91?22.03) pg/ml, and (252.62?27.99) pg/ml, respectively. No estrogen was detected in the primary culture medium. The concentration of estrogen increased in a time-dependent manner and reached the peak at 14 d, and then decreased gradually but remained at a certain level. Conclusion E 2 is secreted by astrocytes in the brain cortex of the 2-day-old neonatal rats.