酸敏感离子通道与脑梗死

急性脑梗死约占全部脑卒中的70%,病死率和致残率高,且极易复发。但目前针对急性脑梗死在时间窗内溶栓、抗凝等治疗手段不能从根本上切实有效地修复受损脑组织,且伴有出血等风险。寻找脑梗死形成发展的原因并予以治疗迫在眉睫。酸中毒是引起缺血性脑损伤的重要机制。大量实验研究表明,酸中毒能加重神经元的缺血性损伤,且其梗死面积与酸中毒的程度直接相关。但缺血产生的酸中毒如何引起神经元损伤的确切机制尚不明确。最近研究发现酸中毒能激活一种在中枢及周围神经中广泛存在的膜通道,即酸敏感离子通道,它对Ca2+通透,能引起细胞内Ca2+超载,同时能激活胞内酶引起细胞内蛋白质、脂类及核酸的降解,加重缺血后脑损伤。本文就酸敏感离子通道1a与脑梗死做一综述。     

The influence of diet on the growth of Stenonema vicarium (Walker) (Ephemeroptera: Heptageniidae)

Laboratory studies compared the growth rate of Stenonema vicarium (Walker) nymphs on diets of detritus and natural stream periphyton. In three consecutive runs of the experiment, growth rates were consistently higher on periphyton (mean growth rate = 2.1% wet wt. d⁻¹) than detritus (mean = 1.8% wet wt. d⁻¹). The starting date of each run also significantly influenced growth rates. In each treatment growth rates generally decreased over the course of the 3 runs, and ca. one-half of the nymphs in the last run did not molt or grow. It appeared that growth of S. vicarium may be partially controlled by seasonal factors.     

The effects of substance P and carbachol on inositol tris- and tetrakisphosphate formation and cytosolic free calcium in rat parotid acinar cells. A correlation between inositol phosphate levels and calcium entry

Both substance P and carbachol produced increases in inositol tris- and tetrakisphosphate and increased cytosolic free [Ca2+] in dispersed parotid acinar cells loaded with fura-2. The increase in [Ca2+]i in response to each agonist was due to a combination of mobilization of internal Ca2+ and entry of extracellular Ca2+. Kinetic studies of the initial response to substance P, and measurement of peak [Ca2+]i, demonstrated that the initial rapid rise in [Ca2+]i was due to both internal release and entry of Ca2+. Substance P could evoke a greater initial increase in [Ca2+]i and inositol trisphosphate than could carbachol. However, after 1 min in the presence of external Ca2+, the maintained [Ca2+]i level in response to substance P was considerably smaller than that seen with carbachol, an effect apparently due to homologous desensitization of the substance P receptor. The two agonists each produced a similar 4-5-fold increase in inositol tetrakisphosphate levels within 30 s; this level was maintained in the presence of carbachol, but decreased with substance P. Similarly, the level of inositol (1,4,5)-trisphosphate decreased after prolonged incubation with substance P. Thus, the maintained level of [Ca2+]i, and by deduction Ca2+ entry, correlated with the levels of inositol (1,4,5)-trisphosphate and inositol tetrakisphosphate; a result consistent with a possible role for these inositol phosphates in the control of receptor-mediated Ca2+ channels.     

黑龙江省三江平原丹顶鹤的数量分布

在地面调查的基础上,我们使用Y-11轻型飞机对黑龙江省三江平原地区的丹顶鹤的数量分布近行了调查,调查时飞行高度80米,航速140公里/小时,续航里程共3748公里。调查结果表明,丹顶鹤在三江平原主要分布在8个地区,其中嘟噜河下游、洪河自然保护区、七星河流域和兴凯湖低地是主要繁殖地,总数量共309只。     

青海省长刺双蚤一新亚种

在整理青海省蚤类标本中,发现长刺双蚤 Amphipsylla longispina Scalon, 1950一新亚种,记述如下。 长刺双蚤共和亚种 Amphipsylla longis pina gongheensis新亚种 鉴别特征 新亚种可动突前缘较直,不动突较细长,阳茎钩突端部似鸟头状;     

Structural relatedness of lysis proteins from colicinogenic plasmids and icosahedral coliphages

The host-lysis-inducing functions of phi X174 protein E and MS2 protein L were recently shown to reside on the N-terminal and C-terminal halves of the two respective lysis proteins. In the present study it is shown that the small lysis proteins encoded in various colicinogenic plasmids share local sequence similarities and certain structural characteristics with the essential peptides of their coliphage-coded counterparts. Despite their dissimilar sizes and origins, it is suggested that the colicinogenic lysis proteins are functionally analogous and evolutionarily related to those of icosahedral single- stranded DNA and RNA phages.      

氟碳乳剂与右旋糖酐对犬缺血心肌侧支循环供氧的影响

本实验在14只麻醉开胸狗心脏上观察了氟碳乳剂与右旋糖酐稀释血液对心肌耗氧量与供应缺血心肌氧量关系的影响。以左室压力-时间指数(SPTI)作为心肌耗氧量的指标,根据冠脉有效侧支血流量(ECF)、PaO_2和 Hb 浓度计算供应缺血心肌的氧量。实验结果表明,低分子右旋糖酐稀释血液后,SPTI 暂时性轻度增加(稀释后30min 时较对照增加7.1±2.7%,P<0.05,稀释后60min 时增加2.8±1.2%,P>0.05),ECF 明显增多(稀释后30min 时较对照增加58.5±6.1%,P<0.01),缺血区边缘心肌氧供需关系未发生明显变化。氟碳乳剂稀释血液后,SPTI 的变化规律与右旋糖酐稀释后相同(稀释后30min 和60min 时分别较对照增加2.5±0.7%和1.9±0.8%)ECF 和 PaO_2升高(稀释后30min 时分别较对照增加53.9±6.7%和93±8.9%),供应缺血心肌的氧量显著增加,缺血区边缘心肌氧供需矛盾明显改善。