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 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 provide the reference basis for reducing the occurrence of nutritional risk by analyzing possible risk factors for nutritional risk status and investigating the relationship between preoperative nutritional risk status and prognosis.Methods We retrospectively analyzed the clinical data of 894 patients(nutritional risk group of 491 cases,non-nutritional risk group of 403 cases) with esophageal cancer resection.The univariate analysis was used to analyze the relationships between nutritional risk status with postoperative complications and length of hospitalization.And the multiple Logistic regression model analysis was applied to analyze the risk factors of nutritional risk status.Results The nutritional risk group had a higher rate of postoperative complications (33.60 ％ vs.19.60 ％,U =-3.429,P =0.001),higher incidence of serious complications (23.01％ vs.8.68％,U =-3.611,P =0.000) and longer hospital stays [(37.20 ± 13.89) days vs.(31.69 ± 13.49) days,t =4.124,P =0.000] than that of non-nutritional risk group.The results of the multiple logistic regression analysis showed that the preoperative nutritional risk factors were associated with the patients' age (OR =1.58,95％ CI:1.101-2.268),number of symptoms entries(OR =7.97,95 ％ CI:6.071-10.463),symptom severity (OR =0.26,95％ CI:0.186 -0.385),and dietary intake (OR =0.62,95 ％ CI:0.482-0.813),P ＜ 0.05 for all.Conclusion The older patients with more severe symptoms and poor diet are more likely to suffer from nutritional risk.Prolonged hospital stay and postoperative complications easily happen in patients with nutritional risk.So patients with preoperative nutritional risk should be given timely and effective nutrition intervention measures,in order to reduce postoperative complications and length of hospitalization.

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.

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.

Objective To study the effect of astrocyte on synapse formation and the molecular mechanism. Methods Cortical astrocytes were isolated and purified from neonatal rats.On the 2h,7th day,14th day and 21th day after passage,we counted the number of astrocytes and the culture medium(astrocyte-conditioned medium,ACM)was harvested to measure the concentration of estrogen(E 2)by using ELISA techniques.Based on the model of pure culures of neonatal cortical neurons,the experimental groups were designed as follows:1.pure neuron cultures(group N);2.ACM cultures(group A);3.mixed cultures(group M);4.E 2 cultures(group E 2);5.ACM+Tamoxifen(estrogen receptor antagonist)cultures(group A+T);6.Tamoxifen cultures(group T).Then synaptic puncta in every group was stained and counted through immunofluorescence,and we also compared the differences in puncta number among those six groups(at 9th day in culture,number/per neuron). Results The numbers of astrocytes were:1?10 4/ml, 1.1?10 6/ml, 1.4?10 6/ml, 1.5?10 6/ml; The concentrations of E 2 were:(ng/L):0, 117?22, 266?22,252?27 respectively.No estrogen was detected in the primary culture medium.The concenteration of estrogen increased in correspondence with the culturing days and reached the peak around at the 14th day, then decreased gradually but kept at a certain high level,and the numbers of synaptic puncta of per neuron in group N,A,M,E 2,A+T,T were:14?3;79?5;83?8;80?6;32?3;29?3 respectively.The treatment of pure neuron culture with ACM increased the number of synapses on per neuron by up to 6 fold by comparison with pure neuronal culture.Exogenic estradiol added into pure neurons can mimick the effect of the ACM.Tamoxifen which is antagonist of estrogen receptor could decrease the effect of ACM by 75%.Conclusion The astrocytes of neonatal rat cortex do secrete E 2.Astrocyte-derived estrogen may be the molecule regulating the synaptic formation through estrogen receptors.

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.