慢性肾功能衰竭病人高同型半胱氨酸血症及其影响因素

目的 :研究慢性肾衰 (CRF)病人血浆同型半胱氨酸 (Hcy)水平及其影响因素。方法 :采用荧光偏振免疫分析法测定 16 0例CRF病人血浆总同型半胱氨酸 (tHcy)水平 ,同时用离子夺获分析法和微离子酶免疫分析法分别检测血浆叶酸(FA)和维生素B12 (VB12 )浓度。结果 :CRF病人血浆tHcy水平 (2 2 6 9± 12 16 ) μmol/ )明显高于正常对照组 (7 97±2 6 5 ) μmol/L ,CRF病人高同型半胱氨酸血症的发生率为 82 5 0 % ,其中血液透析组血浆tHcy水平 (2 4 13± 12 6 8μmol/L ,n =73)明显高于持续性非卧床腹膜透析 (CAPD)组 (16 4 3± 5 5 8μmol/L ,n =19)和非透析治疗组 (19 79± 10 5 7)μmol/L ,(n =6 8) ,但血浆FA和VB12 与正常对照组均无明显差别 (P >0 0 5 )。CRF病人血浆tHcy水平与血浆FA浓度均呈负相关关系 ,未经透析的CRF病人血浆tHcy水平与内生肌酐清除率和血浆FA水平呈负相关 ;透析治疗组血浆tHcy水平与血浆FA浓度呈负相关。血透 4h使血浆tHcy下降约 4 0 0 % ,透析后 2 0h回复到透析前水平的 76 0 %～86 0 % ,但在采用血仿膜和聚砜膜透析的病人之间 ,血浆tHcy水平无明显差异。结论 :CRF病人普遍存在高同型半胱氨酸血症 ,但没有明显的FA和VB12 缺乏 ,CRF时肾脏损害削弱了对Hcy的代谢或清除能力 ,     

刺梨酸的分离与结构研究

从刺梨中分离出一种新的五环三萜酸,命名为刺梨酸。通过光谱分析和衍生物的制备,确定其化学结构为2β,3α,7β,19α-四羟基乌苏-12-烯-28-羧酸。     

维生素B_(12)注射液稳定性的研究

作者用恒温加速试验法研究了维生素B_(12)注射液的稳定性。结果表明:该注射液的稳定性在pH值4.80左右较好,加络合剂可增加其稳定性,有效期为5年。     

Gating modifier peptides as probes of pancreatic beta-cell physiology.

Pancreatic beta-cells depolarize in response to glucose and fire calcium-dependent actions potentials that trigger insulin secretion. The major current responsible for action potential repolarization in these cells is a delayed rectifier and Kv2.1 subunits are thought be a major contributor of the delayed rectifier channels. Hence, blockers of Kv2.1 channels might prolong action potentials and enhance calcium influx and insulin secretion. However, the lack of specific small molecule Kv2.1 inhibitors has hindered the testing of this mechanism. Importantly, several gating modifier peptides inhibit Kv2.1 channels in a relatively specific fashion. Hanatoxin (HaTX) and guangxitoxin-1 (GxTX-1) are examples that have been used to probe the role of Kv2.1 channels in beta-cell physiology. Both HaTX and GxTX-1 strongly inhibit the Kv current of beta-cells from various species, arguing that Kv2.1 subunits contribute significantly to the beta-cell delayed rectifier. GxTX-1 prolongs glucose-triggered action potentials, enhances glucose-dependent intracellular calcium elevations and augments glucose-dependent insulin secretion. Taken together, these data suggest that blockers of Kv2.1 channels may be a useful approach to the design of novel therapeutic agents for the treatment of type 2 diabetes. These studies highlight the utility of gating modifier peptides in the study of physiological systems.     

多发性硬化患者中IL-12和孕酮的检测及其临床意义

目的检测IL-12和孕酮在多发性硬化(MS)患者中的水平,探讨男、女性多发性硬化患者存在的发病机制,比较男、女性MS患者在临床上发病的差异。方法采用酶联免疫(ELISA)法检测60例MS患者的脑脊液和40例患者血液中IL-12的水平,应用放射免疫法测定40例MS患者血液中孕酮的含量,并与40例正常对照组比较(以上标本男女各半)。结果男、女性MS患者血液中和脑脊液IL-12的含量明显高于正常对照组(P<0.01);女性患者血液中孕酮的含量明显低于正常对照组(P<0.01),男性患者血液中孕酮的含量与正常对照组差别不明显(P>0.05);女性患者血液中孕酮对IL-12的含量存在负相相关作用(r=-0.80,P<0.01),男性相关作用不明显(r=-0.38,P>0.05)。结论IL-12参与多发性硬化的发病过程;孕酮可能是男、女性患者发病差异性的原因之一。     

白介素-12家族与实验性自身免疫性脑脊髓炎的研究进展

实验性自身免疫性脑脊髓炎(EAE)是自身反应性CD4+T细胞,即辅助性T细胞(Th细胞)介导的自身免疫性中枢神经系统脱髓鞘性炎症,在EAE的发病中,Th细胞分泌的细胞因子起了重要的调节作用。白介素-12(IL-12)家族由IL-12和最近发现的白介素-23(IL-23)、白介素-27(IL-27)组成,是一类结构相似、具有共价结合的杂化双链的细胞因子,在细胞免疫尤其是Th1型炎症反应中,起重要的调节作用。本文综合论述了IL-12家族各成员与EAE的关系的研究,揭示了各因子在EAE发生发展中的作用。     

Effect of amyloid peptides on the increase in TrkA receptor expression induced by nicotine in vitro and in vivo

The ability of nicotine to induce a cytoprotective or neuroprotective action occurs through several down-stream mechanisms. One possibility is that the drug increases the expression of tyrosine kinase A (TrkA) nerve growth factor (NGF) receptors. Certain β-amyloid peptides (e.g., Aβ1–42) have been shown to bind with high affinity to α7 nicotinic receptors and thus interfere with a potentially neurotrophic influence. Treatment of differentiated PC-12 cells with nicotine produced a concentration-dependent increase in cell-surface TrkA receptors that occurred concomitantly with cytoprotection. The effect of nicotine was blocked by either of the α7 receptor antagonists α-bungarotoxin (α-BTX) or methyllycaconatine. The cytoprotective action of nicotine also was inhibited by pretreatment with 10–100 nM Aβ1–42. Nicotine also was administered (four injections of 30 μg, spaced evenly over 24 h) to rats by direct injection into a lateral cerebral ventricle. Brain TrkA expression was increased significantly in hippocampus and entorhinal cortex (up to 32% above control), with no changes found in cerebral cortex or hypothalamus. The nicotine-induced increases in TrKA expression in hippocampus and entorhinal cortex were significantly inhibited by 10 μg α-BTX or by 10 nmol Aβ1–42. Therefore, physiologically relevant concentrations of Aβ1–42 can prevent nicotine-induced TrkA receptor expression in brain regions containing cholinergic neurons susceptible to the neurotoxicity associated with Alzheimer’s disease.     

喷雾(冰冻)干燥法制备钠、锂快离子导体

对两种性能较好的快离子导体Na_3Zr_2Si_2P_3O_(12)(Nasicon)和Li_(1.8)Ti_(1.2)·Cr_(0.8)P_3O_(12)用喷雾干燥法和冰冻干燥法制备粉料和陶瓷烧结,并对样品进行了X射线衍射分析,形貌和显微结构观察以及阻抗谱测量等。实验结果表明:两种方法制备的粉料具有颗粒细,均匀性好,合成温度低等优点。在300℃时,两种样品的电阻半分别为10.05 Ω.cm和94.8 Ω.cm。激活能分别为0.25 eV和0.27ev。     

The growth and development of vegan children

The results of prospective study on the growth and diets, estimated from 7-day weighed food intake records, of 20 life vegan children (aged 5.8–12.8 years) are presented. The growth and development of the children were normal but they tended to be lighter in weight and exceptionally lean compared with standards. Heights were around the median of the Tanner-Whitehouse standards but were lower than the medians recently proposed by the Department of Health. Energy intakes were similar to those reported in children of the same age in the general population, but dietary fibre intakes were very high which may have influenced the digestible energy. Sugar provided an average 15.6% of the dietary energy and this was supplied mainly by fruit and fruit juice. Mean fat intakes were close to the dietary reference values. Daily intakes of essential nutrients generally met the amounts recommended, with the exceptions of calcium and vitamin B₁₂. Many children received supplementary sources of vitamin B₁₂ and only two children had intakes below the lower recommended nutrient intake. Intakes of saturated fatty acids were low and those of linoleic acid were high. The ratio of linoleic/α-linolenic acid was high. As docosahexaenoic acid is absent from vegan diets, it is suggested that vegans should use oils with a lower ratio of linoleic/α-linolenic acid. Future studies should also consider the influence of a vegan diet on retinal function. None of the children was immunized against whooping cough and 11 had not been immunized against polio: 16 of the children had suffered from whooping cough. Future studies need to take into account factors other than diet when assessing the health of vegans. The results of this study show that children can be successfully reared on a vegan diet providing sufficient care is taken to avoid the known pitfalls of a bulky diet and vitamin B₁₂ deficiency.     

超抗原TSST-1之靶TCRVβHV4序列的特征分析

首先对人和小鼠的TCRVβ的氨基酸序列进行多序列对准,就Vβ之HV4片段进行比较,分析与超抗原TSST-1结合的四种Vβ（小鼠Vβ3、Vβ15、Vβ17和人Vβ2）之HV4序列内是否存在特定的氨基酸残基排列主型。结果发现:小鼠Vβ3和Vβ17的HV4具有特异的RFSAXCXSNS主型,而小鼠Vβ15和人β2的HV4则含独特的KFXIXH主型。提示:与TSST-1结合的四种Vβ所对应的T细胞识别表位可能不止一个。