石斛合剂对高脂高糖糖尿病大鼠心肌细胞Ca^2+代谢的影响

目的以糖尿病心肌病大鼠为研究对象,探讨石斛合剂对糖尿病心肌病心肌细胞Ca^2+代谢的影响。方法 Wistar大鼠24只,取5只作为正常组,余19只采用高脂高糖饮食联合链脲佐菌素腹腔注射进行糖尿病心肌病造模。成模后,随机分为模型组、二甲双胍组、石斛合剂组。二甲双胍组、石斛合剂组分别予二甲双胍、石斛合剂灌胃,正常组、模型组予生理盐水灌胃。4周后,测空腹血糖,取左心室心肌组织进行组织病理学观察和心肌细胞内游离钙(MyoCa^2+)浓度测定,Western blot法检测肌浆网Ca^2+-ATP酶(SERCA2a)、L型钙通道α1C亚单位蛋白(CACNA1C)蛋白表达,RT-PCR法测定SERCA2a mRNA表达。结果石斛合剂组心肌纤维较模型组、二甲双胍组排列整齐,断裂较少。与正常组比较,模型组血糖、心肌细胞MyoCa^2+含量和CACNA1C蛋白表达明显升高(P<0.01,P<0.05),SERCA2a mRNA和蛋白表达明显降低(P<0.01)。与模型组比较,石斛合剂组血糖、心肌细胞MyoCa^2+含量和CACNA1C蛋白表达明显降低(P<0.01,P<0.05),SERCA2a mRNA和蛋白表达明显升高(P<0.01,P<0.05);二甲双胍组血糖明显降低(P<0.01)。与二甲双胍组比较,石斛合剂组心肌细胞MyoCa^2+含量明显降低(P<0.01,P<0.05),血糖、SERCA2a mRNA和蛋白表达明显升高(P<0.05)。结论石斛合剂通过提高SERCA2a mRNA和蛋白表达,加快摄取Ca^2+的速率,降低细胞质Ca^2+负荷,缓解钙超载,最终达到维持糖尿病心肌病钙稳态的作用,有效维持心肌细胞的正常收缩舒张功能;其降糖作用不是预防糖尿病心肌病的主要机理,而在于抑制CACNA1C蛋白表达,抑制钙诱导钙释放过程。     

Transfer of 45Ca and 36Cl at the blood-nerve barrier of the sciatic nerve in rats fed low or high calcium diets

Unidirectional fluxes of 45Ca, 36Cl, and of [3H]mannitol from blood into the sciatic nerve and cerebral cortex were determined from 5- and 15-min uptakes of these tracers after an intravenous (i.v.) bolus injection in awake rats. Rats were fed diets for 8 wk, that had either a low (0.01% wt/wt), normal (0.67%), or high (3%) Ca content. Plasma [Ca] was 32% less and 11% more in rats fed low (LOCA) and high Ca diets (HICA), respectively, than in rats fed a normal Ca diet (CONT). The mean permeability-surface area product (PA) of 45Ca at the blood-nerve barrier was about eightfold higher than at the blood-brain barrier in the same animals and did not differ significantly between groups (greater than 0.05). Mean PA ratios of 45Ca/36Cl for the blood-nerve and blood-brain barriers in CONT rats, 0.52 +/- 0.04 and 0.40 +/- 0.02, respectively, were not significantly different from corresponding ratios in LOCA and HICA groups, and corresponded to the aqueous limiting diffusion ratio (0.45). Our results show no evidence for concentration-dependent transport of Ca over a plasma [Ca] range of 0.8-1.4 mmol/liter at the blood-nerve barrier of the rat peripheral nerve, and suggest that Ca and Cl exchange slowly between nerve and blood via paracellular pathways.     

与铁稳态有关的生物分子

根据近几年来发表的与铁稳态有关的生物分子的研究文献 ,将这些生物分子根据其与铁的吸收、转运、储存以及对铁稳态的监控调节等方面的关系 ,对这些生物分子进行了分类。特别是对细胞膜载体、运铁蛋白受体、铁调蛋白及铁反应元件等作了较为详细地论述     

146例女性不孕症的病因分析

目的 分析女性不孕的病因。方法 收集1990-2000年我院女性不孕症146例，不孕时间2年以上。结果 不孕症的主要原因是子宫因素，感染因素及内分泌失调，原发性不孕以子宫因素为主，继发性不孕则以感染因素为主。结论 女性不孕症的原因常是多因素的，必须采用综合治疗，才能提高妊娠率。     

Inward rectifying potassium channels in human malignant glioma cells

Human glioma cells obtained from established cell lines (Tp-276MG, Tp-301MG, Tp-378MG, Tp-483MG and U-251MG) were analyzed for the presence of ion channels with the tight-seal voltage clamp technique. The current-voltage relation revealed a marked inward rectification at hyperpolarizing voltages, due to the presence of inward rectifying K-channels in cells from all studied cell lines. These channels were conducting when the membrane potential was more negative than the K-equilibrium potential. The slope conductance for the inward K-currents (g_Ki) was affected both by [K⁺]_i and [K⁺]₀. g_Ki was proportional to [K⁺]₀ raised to 0.35 or 0.50, of which the larger value was measured in the presence of low [K⁺]_i (25mM). The rectification was not significantly different in cells perfused with Mg-free EDTA-buffered internal solution. Tl⁺ was 3.5 times more permaant than K⁺. g_ki was blocked by Cs⁺ (1 mM) in a voltage-dependent way (more effective in the hyperpolarized membrane), and by Na⁺ (154 mM) depending on voltage and time. From measurements of unitary current events in membrane patches (outside out or cell attached) the conductance of the single inward rectifying channel was estimated to be 27 ± 7 pS. This type of ion channel may be important for K-uptake by glial cells and hence for the K-homeostasis in the brain.     

Integrinα4在骨肉瘤中的表达与意义

Objective： To investigate the expression of integrin α4 in osteosaxcoma and significance. Methods- Forty-six patients with osteosarcoma （Enneking Ⅰ-Ⅲ） were analyzed for the expression of α4 integrin subunit using immunohistochemical method. Results： Twenty-nine （63.04%） of 46 samples demonstrated positive （＋-＋＋） integrin α4 expression. Loss expression of integrin α4 was observed in the patients with advanced Enneking stage （P=0.0040） and with metastatic disease at presentation （P=0.0158）. Integrin α4 expression correlated with cell differentiation, the level of malignancy and the invasive behavior of osteosaxcoma. Conclusion： The loss expression of integrin α4 subunit might be a predictor indicating the invasive potential of osteosarcoma and play a role in metastasis of osteosaxcoma patients.     

生长激素缺乏儿童的酸碱平衡研究

目的 :探讨生长激素缺乏 (GHD)和特发性矮身材 (ISS)儿童血浆实际碳酸氢盐浓度 (AB)差异 ,以及碳酸氢盐标准差评分 (SDS)在 GHD诊断中的价值。方法 :对 4 7例矮小症儿童作血气分析及电解质测定及 GH激发试验 ,根据 GH激发试验的峰值分为 GHD和 ISS两组 ,比较两组血浆 AB、碳酸氢盐 SDS、阴离子间隙 (AG)的差异。结果 :GHD儿童血浆 AB、碳酸氢盐 SDS分别为 (2 2 .6 0± 1.2 9) mmol/L、- 0 .2 7± 0 .98,明显低于 ISS组 [(2 3.80±0 .95 ) mmol/L、0 .6 4± 0 .73],P<0 .0 1;而 AG GHD组为 (11.73± 4 .5 2 ) mmol/L高于 ISS组 [(7.87± 1.70 ) mmol/L],P<0 .0 1。在碳酸氢盐 SDS≤ 1s的矮小儿童中 ,72 % (31/4 3)患儿为 GHD。结论 :GHD儿童血浆 AB、碳酸氢盐SDS明显低于 ISS儿童 ,血浆碳酸氢盐 SDS≤ 1s者应高度怀疑 GHD。