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

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 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 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 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 observe the localization of NG2 positive cells and morphological character in the brain of adult rats. Methods Immunohistochemical method was applied to determine the expression of NG2 positive cells in the cerebrum cortex, hippocampus, dentate gyrus, thalamencephalon and hypothalamus of adult rats. Image analysis program Image Pro Plus 5.0 was used to count the positive cells and for statistic analysis. Results NG2 positive cells were strongly expressed in multiple brain regions of adult rats, of which strongest signals were centralized in gray and white matter of cerebral cortex, hippocampus, dentate gyrus, thalamic subventricular zone and hypothalamic periventricular region. The NG2 positive cells were seen with abundant process arborization which bifurcated two or more times. The soma of NG2 positive cell displays a star-like morphology with different shapes in the gray and white matter of cerebrum cortex. Conclusion NG2 positive cells are numerous in adult rat brain and display the special glial with a stellate morphology.

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.

AIM: To observe the effect of altitude hypoxia on glutamate, aspartate and nitric oxide synthase (NOS) in the rat hypothalamus. METHODS: Using altitude hypoxia model, amino acid analysis system and the NADPH-d histochemistry, we determined the content of glutamate, aspartate and the number of NADPH-d neurons in the rat hypothalamus. RESULTS: After altitude hypoxia, the contents of glutamate, aspartate in the hypothalamus of rats were increased significantly, densely and deeply stained NADPH-d neurons were seen in hypothalamic paraventricular nucleus (PVN)and supraoptic nucleus(SON). If rat were pretreated with the NMDA receptor blockers Ketamine (ip,40 mg/Kg)or AP-V(i.c.v, 10 ?g) , the number of NADPH-d neurons in the rat hypothalamic PVN and SON was markedly less than that in corresponding altitude hypoxia group. CONCLUSION: NMDA receptor may take part in the expression of hypothalamic NOS induced by altitude hypoxia.

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.

Objective To investigate the effects of chitin on the functional recovery after sciatic nerve axotomy. Methods Upon silicone-tubulization of the transected sciatic nerve in the adult rats, either 0.9% saline or 1% chitin solution was injected into the silicone chamber. The status of functional recovery of the injured sciatic nerve was observed by electrophysiological analysis, hydrogen-peroxide oxidoreductase (HRP) retrograde trace method, and axon morphometric analysis at 30 and 90 d respectively after sciatic nerve transection. Results ① Chitin shortened the latent period of CMAP by 1.79 ms and 1.29 ms, promoted the nerve conduction velocity by 16.00 m/s and 22.00 m/s, enhanced the amplitude by 8.17 mv and 12.42 mv, respectively, at 30 and 90 d after sciatic nerve transection (P