广西产眼镜王蛇毒α-神经毒素基因的分子克隆及序列分析

为获得眼镜王蛇（Ophiophagus hannah,简称Oh）蛇毒α－神经毒素（α-NT）的基因序列,依据眼镜蛇科不同毒蛇种类来源的α－NT基因有较高的同源性,设计1对上下游引物,为克服引物带来模糊扩增,在蛋白编码部分再设计1对上下游特异引物,用Nacleospin RNA Kit法从3条活眼镜王蛇毒腺中提取mRNA,以3′端引物合成的cDNA作为模板进行PCR扩增反应,测定产物的核苷酸序列,得到全长474bp的眼镜王蛇cDNA基因核苷酸序列。该核苷酸序列的信号肽与眼镜蛇树属Pseudonnaja textilis(Pt)、海蛇Laticauda semifasciata(Ls)100%同源,与眼镜蛇南洋亚种Naja sputatrix (Ns)、银环蛇（Bungarus multicinctus)(Bm)96.8%同源;蛋白密码部分有83．3％与Ns、79．2％与Pt、76．4％与Ls、74．1％与Bm同源。信号肽后紧接着的72个氨基酸有90．3％与已发现的眼镜王蛇毒长链α-NT Toxin a同源,大约有73．6％与Toxin b、69．7％与Oh-4、66．7％与Oh-5、56．9％与Oh-6A和6B同源,并与α－银环蛇毒素54．2％同源。说明新发现的眼镜王蛇cDNA是一条长链α-NT基因。     

陡脉冲肿瘤治疗仪的研制及应用

在一定电场强度陡脉冲的作用下,细胞膜会形成大量微孔,其数量和孔径会随电场强度的增加而激增,从而引起膜组织断裂,导致细胞死亡,这种现象被称为不可逆性电击穿,为了研究陡脉冲对肿瘤细胞的不可逆性电击穿,应用现代电力电子技术和高电压新技术,研制出了一套脉冲峰值、脉冲宽度、脉冲重复频率和脉冲陡度独立可调的能量可控陡脉冲肿瘤治疗仪。分析了该治疗仪各部分电路的工作原理,在实验室调试成功的基础上,应用该仪器对人卵巢腺癌SKOV3细胞进行了细胞实验,调试时的示波器实测波形和细胞实验的电镜结果表明,该治疗仪性能稳定,能够方便地调节输出脉冲的能量,能有效地杀伤肿瘤细胞。     

Defining the resistance to oxygen transfer in tissue hypoxia

Studies of O2 supply in freshly isolated adult mammalian cells provide new insight into the factors that limit mitochondrial oxygenation in vivo. Of particular importance, mitochondria are present at high densities and often in apparent clusters, both of which contribute to local O2 gradients under hypoxic conditions. Current evidence indicates that the mitochondrial distribution is a component of the differentiated phenotype of adult mammalian cells and that specific motors and anchoring mechanisms are present to allow redistribution in response to developmental, physiological and pathological challenges. To compare the importance of resistance to O2 transfer under different conditions and at different sites along the supply path in vivo, a simple mathematical expression of relative resistance to O2 supply is introduced. Under various pathophysiological conditions, this resistance increases in specific regions of the pulmonary, circulatory or cellular supply path and results in O2 deficiency in the mitochondria. Regardless of cause, the relative resistance increases dramatically in the vicinity of mitochondrial clusters during hypoxia.     

Dopamine-induced relaxation in human pulmonary arteries

Dose-dependent relaxations were induced by dopamine in human pulmonary arteries that had been contracted with prostaglandin F2 alpha without alpha-adrenergic blocking agents. The dopamine-induced relaxation was inhibited by haloperidol and fluphenazine, but not by domperidone, suggesting that this relaxation was mediated via DA1 receptors.     

Effect of L-carnitine and stimulated lipolysis on muscle substrates in the exercising rat

To test the effect of L-carnitine on glycogen sparing when fat oxidation is increased, 100 mg/kg/d were given to rats orally for 3 days, resulting in 1.8-fold higher muscle carnitine levels. Even when FFA were raised by heparin-stimulated lipolysis, the rate of glycogen degradation was not reduced during exercise.     

Comparative platelet anti-aggregant activity of D-cysteinolic acid analogues

D-Cysteinolic acid (1) analogues with an S-C-C-N skeleton showed increased platelet anti-aggregant activity in the following order: 2-aminoethanesulfonic acids, thiazolidines, 2-aminoethanethiols and 2-aminoethyl disulfides. Methyl substitutions at the 2-position potentiated the activity. Of these analogues, bis [(R)-2-aminopropyl] disulfide was the most potent inhibitor of platelet aggregation, with about 600-fold the activity of (1).     

Regional distribution of thiamin pyrophosphokinase in rat brain

The highest specific activity of thiamin pyrophosphokinase was found in the cerebellum, and lower activity in cerebral cortex and midbrain. The regional difference in the enzyme activity was similar to that in thiamin content and the influx rate in rat brain, suggesting that the enzyme is involved in the thiamin transport.