BACKGROUND: The rare earth elements (Res) have multiple bio-activities and some extent neurotoxicity, Because of their distinct physical and chemical properties. The studies on neuromuscular junction and sympathet ic ganglia have shown that some Res, such as lanthanum(La), gadolinium (Gd),etc, exert considerable effects on synaptic transmission, but the effects and mechanism of Samarium on synaptic transmission are still unknown.OBJECTIVE: To investigate the effects and impossible mechanism of Samarium Chloride (SmCl3) on the nicotinic transmission in the isolated sympathetic ganglia, superior cervical ganglion (SCG) of rats.DESIGN: Controlled experimental study based on cells.SETTING: Department of Pharmacology, Guangxi Medical University. MATERIALS: Totally 40 adult Wistar rats (weighing 250-300 g) of either sex, provided by the Experimental Animal Center of Guangxi Medical University, were used in this study. SmCl3 was made by the chlorination of Samarium Oxide with purity 99.5% and relative molecule mass 348.7, presented by Professor Liu Da-yuan, Guangxi Medical University. Acetylcholine chloride (Ach) and carbachol (Carb) were purchased from Sigma.METHODS: The experiment was completed at the neuropharmacology lab of the experimental center of Guangxi Medical University from September 2001 to December 2002. After sacrificing animals by acute exsanguination,SCG together with their preganglionic nerve trunks were isolated rapidly,then transferred to the recording chamber, the preganglionic nerve trunk was drawn into a suction electrode for orthodromic stimulation. The ganglia were superfused continuously with a Krebs solution, saturated with 950 mL/L 02 and 5mL/L CO2, pH 7.4±0.05, (34±0.5) ℃.The fiber containing glass microelectrodes filled with 3 mol/L KC1 (30-60 MΩ tip resistance) were used to impaled cells and do intracellular recording. The fast excitatory postsynaptic potentials (FEPSPs) were evoked in SCG neurons by single pulse stimulations (0.2-0.5 Hz, 0.5-1.0 ms, 2-10 V)on preganglionic nerve trunk. The remarkable membrane depolarization would be recorded in SCG neurons by superfusing ganglia with exogenous Ach (0.1 mmol/L) or Carb(0.1 mmol/L) for 30-60 s. The effects of 1×(10-7-10-4) mol/L SmCl3 on FEPSPs, membrane potentials, membrane resistance, exogenous Ach and Carb-induced membrane depolarization of SCG neurons were investigated in this experiment.The effects of SmCl3 on the facilitation of high Ca2+ (10 mmol/L ) on FEPSPs were also be observed, namely, first superfusing the ganglia with high Ca2+ (10 mmol/L)to facilitate FEPSPs, then superfusing the ganglia with Ca2+(10 mmol/L)contained SmCl3. All the drugs were solved in Krebs solution or improved Krebs solution and applied to ganglia by superfusion in known concentration.The bioelectricity difference before and after the drug superfusion were analyzed by paired Student's t test.MAIN OUTCOME MESURES: ①Effects of SmCl3 on FEPSPs.②Effects of SmCl3 on membrane potentials and membrane resistances. ③Effects of SmCl3 on exogenous Ach and Carb-induced membrane depolarization. ④Effects of SmCl3 on the facilitation of high Ca2+ (10 mmol/L ) on FEPSPs.RESULTS: ① 1 ×(10-7-10-4)mol/L SmCl3 could reversibly depressed the FEPSPs of rats SCG neurons [the amplitude inhibitory percentage of FEPSPs of l×10-4, 1×10-5, 1×10-6, 1×107 mol/L SmCl3 was (49.78±13.85)%(n=20),(39.05±4.05)%(n=10),(29.83±9.73)%(n=10)and (16.30±2.16)%(n=10)respectively (P ＜ 0.05-0.01)].1×10-4 mol/L SmCl3 could chang Aps into FEPSPs (n=5).②The membrane depolarization induced by Ach (n=5) and Carb (n=7) were not significantly changed by 1×10-4 mol/L SmCl3(P ＞ 0.05).③The membrane potential and membrane resistance were not significantly altered by 1×(10-7-10-4)mol/L SmCl3(n=67), P ＞ 0.05. ④1×10-4 mol/L SmCl3 could antagonized the facilitation of high Ca2+ (10 mmol/L ) on FEPSPs (n=5), P ＜ 0.01.CONCLUSION: SmCl3 can depresses nicotinic transmission in rats sympathetic ganglia by presynaptic mechanisms, perhaps due to its inhibition on Ca2+ influx.

Objective To acquaint the condition of learning burnout of medical students and to explore the relationship of learning burnout with professional commitment and social support. Methods 610 medical students were evaluated with Learning Burnout Scale, professional commitment scale and social support scale. Results ①In general, learning burnout index of medical students was 2.84±0.49; in terms of gender difference, male students [(2.83±0.65) and (3.08±0.61)] were higher than females[(2.70±0.63) and (2.96±0.60)] at the level of emotional turndown and behavioral unsuitableness, the difference was statistically significant( P <0.05); in terms of grades, medical students'learning burnout of different grades was significant( F =4.244,P <0.01); there was no difference in profession. ②Learning burnout was significantly negative correlation with professional commitment and social support( P <0.01). ③Multiple regression analysis showed that affective commitment and family support had significant predications on learning burnout of medical students( P <0.01). Conclusion Medical students'learning burnout level is comparatively high, learning burnout closely relates to professional commitment and social support.

Objectives:To detect the altered expression of SOCS-3 and GHR gene in intraabdominal infection and its relationship to growth hormone resistance.Methods:Liver expression of SOCS-3,GHR and IGF-I mRNA were detected by RT-PCR in control and intraabdominal infected rats,serum growth hormone levels were measured by RIA in two groups.Results:Serum concentrations of growth hormone were elevated more obviously in infected rats than controls,they were (0.843±0.17)ng/ml and (0.614±0.138)ng/ml respectively,the difference was significant (P<0.05).Liver GHR mRNA levels were decreased by 57.2% in infected rats compared with control rats.SOCS-3 mRNA was weakly expressed in control rats,however,it was strongly expressed in infected rats and had a 312.8 % increase.Liver IGF-I mRNA levels were reduced by 45.3% in infected rats compared with control rats.Conclusions:The elevated SOCS-3 and reduced GHR mRNA expression may contribute to the growth hormone resistance in intraabdominal infection.

Histocytological Preparation Techniques ; methods ; Microtomy ; methods ; Tissue Embedding

Food Contamination ; Humans ; Infant ; Triazines ; toxicity ; Urinary Calculi ; diagnosis ; etiology ; therapy

The cause of sarcoidosis is still unknown. However,the histological similarity between the disorder and tuberculosis suggests that M. tuberculosis might contribute to the pathogenesis of sarcoidosis. In attempting to confirm the relation between M. tuberculosis and sarcoidosis,we used the polymerase chain reaction to detect M. tuberculosis DNA from formalin--fixed,paraffin--embeded skin biopsy specimens of 12 patients with sarcoidosis, M. tuberculosis DNA was found in 4 patients. This finding suggests an aetiological role for M. tuberculosis in sarcoidosis.

Objectives:To investigate the role of endotoxin, TNF ? and IL 6 in inducing the growth hormone insensitivity at the receptor and post receptor levels. Methods:Spague Dawley rats were injected with endotoxin, TNF ?, and IL 6 respectively and were killed at different time points. The liver expressions of IGF 1, GHR and SOCS 3 mRNA were detected by RT PCR, the GH levels were measured by radioimmunoassay,and the levels of TNF ? and IL 6 were detected by ELISA. Results:Serum growth hormone levels at each time points after LPS iv injection did not have significant changes compared with control rats without iv injection of LPS, TNF ? and IL 6 levels were elevated rapidly after LPS injection, but TNF ? levels returned to normal quickly. The most remarkable down regulations for liver IGF 1 mRNA and GHR mRNA occurred at 12h and 8h respectively after LPS infusion. The liver SOCS 3 mRNA was weakly expressed in control rats. However, it was strongly up regulated after LPS injection and had a 7.84 times increase at 1h. The linear regression analysis had shown a positive correlation between IL 6 levels and liver SOCS 3 mRNA expressions. Liver GHR mRNA expression was obviously down regulated after TNF ? iv injection, but there was no effect on liver SOCS 3 mRNA expression. IL 6 up regulated the liver SOCS 3 mRNA expression, but it could not affect the liver GHR mRNA expression. Conclusions:The growth hormone insensitivity could be induced by LPS injection, which was associated with down regulated GHR mRNA expression at receptor level and up regulated SOCS 3 mRNA expression at post receptor level. The biological activities of LPS are mediated by TNF ? and IL 6 indirectly.And TNF ? and IL 6 exert their effects on the receptor and post receptor levels respectively, but the effect of TNF ? is of hysteresis.

Phenols are organic pollutants of high priority concerns because of their toxicity and possible accumulation in the environment. It is important to treat and recover phenols from wastewater economically and effectively. In this paper,the source and harm of phenolic wastewater were introduced. The situation and progress in treatment process of phenolic wastewater,including absorption,extraction,oxidation process,and biological treatment are also summarized. The characteristics,main problems ,area and further application of each treatment process are pointed out. The developing trend on combination treatment of phenolic wastewater is further described.

Objective To evaluate the application of Snodgrass urethroplasty for failure hypospadias repairment.Methods Eighty-four cases of failure hypospadias were treated by Snodgrass urethroplasty from 2001 to 2005.The average age of patients was 3.7 years old.In the meantime,Duplay procedure was undertaken for other failure hypospadias with enough penile skin(76 cases).Results There were 64 cases cured,6 cases with urethral stricture and 14 cases with urethral fistula in 84 failure hypospadias cases.Sixty-one cases were cured in 76 cases used Duplay procedure.Conclusion Snodgrass is recommended for failed hypospadias cases with narrow urethral plate.

Objective:To explore the influential factors of cognitive change among Chinese oldest-old.Method: Three waves of data from the Chinese Longitudinal Healthy Longevity Survey(CLHLS)were analyzed with a two-level repeated measures model.Results:In baseline,the male had a higher mean MMSE score than the female(27.0?3.7/24.4?5.6,P