医蛭唾液腺分泌物:成分、功能及应用前景

本文对医蛭唾液腺分泌物中主要活性物质的认识发现过程、结构与功能以及医学应用的实例和前景作了扼要的综述。     

伍氏游仆虫接合过程中老大核后碎块的去向

在伍氏游仆虫(Euplotes woodruffi)接合后体发育过程中,已呈退化状态的老大核后碎块,在细胞第二次形态发生时,逐渐恢复其正常形态结构。T形新大核原基向后延伸而与恢复正常形态的老大核后碎块紧密靠拢。此时在光镜下观察,很容易误认为二者已融合为一。但在接合后体分裂之前,老大核后碎块再次瓦解,T形大核原基缩短成棒状而与老大核后碎块分开,此时二者界限分明。细胞分裂后,残存的老大核后碎块停留于后子虫中,最后被吸收。几个关键时期大核原基和老大核后碎块DNA含量的测定,也证明新老大核不融合。本文还讨论了老大核后碎块在有性过程中的功能。     

中华绒螯蟹血淋巴20-羟蜕皮酮诱发蜕皮和卵巢发育的作用

通过放射免疫法测定了中华绒螯蟹蜕皮周期血淋巴20-羟蜕皮酮(20-HE)含量的变化。血淋巴20-HE同卵母细胞发育各个阶段有密切的时相关系:在卵母细胞小生长期血淋巴20-HE持续上升,经青春蜕皮进入卵母细胞大生长期后又迅速降低。不能及时青春蜕皮的青春期前雌蟹,稍后仍出现20-HE下降的趋势。对不同实验条件和生理状态下雌蟹的比较表明,20-HE具有诱发蜕皮的特性。卵母细胞早期生长必需高浓度的血淋巴20-HE。外源注射的20-HE有刺激卵巢增重的作用。     

The sensory functions of the cerebellum of the thornback ray,Platyrhinoidis triseriata

Summary Single unit spikes and evoked field potentials were recorded in different parts and depths of the corpus cerebelli and auricle of immobilized rays before and after stimulating with light, electric fields, touch, tail bending and direct shock to mechanoreceptive nerves of the lateral line.Discrete areas of the cerebellum are responsive to these modalities and the areas show limited overlap; they are all distinct from the area reported by Plassmann to be responsive to angular acceleration. The visual and tactile-proprioceptive areas are large; the electric area is small. Most units are excited only by one modality.The tail is represented only in the posterior lobe; trigeminal innervation extends from the posterior onto the anterior lobe, suggesting some topographic projection.The dynamic characteristics of the responses were examined particulary in the visual units. To a flash, units discharge up to six bursts of spikes in 500 ms. This pattern is reduced at repetition rates > 1/s; above ca. 4/s units tend to fire irregularly. Various kinds of units are found in respect to the succession of responses to short trains of flashes. Some units fire much better to objects moving in a limited visual field with a certain direction and rate.Abbreviation EP evoked potential     

Mechanism of action of the nitrosoureas: formation of 1,2-(diguanosin-7-yl) ethane from the reaction of BCNU (1,3-bis-[2-chloroethyl]-1-nitrosourea) with guanosine

A crosslinked dinucleoside, 1,2-(diguanosin-7-yl) ethane, has been isolated from the reaction of guanosine with the antitumor agent, BCNU. The formation of this product suggests that DNA crosslinking, which may be responsible for the cytotoxicity of BCNU, could occur through such dinucleosides.     

On the characteristics of mitochondrial monoamine oxidase in pancreas and adipose tissues from genetically obese mice.

The substrate specificity of mitochondrial monoamine oxidase (MAO) in pancreatic and adipose tissues of obese mice and their lean counterparts was determined. The pancreatic MAO of obese mice had a greater specific activity than that of the lean mice. The white adipose tissue MAO was found to be more active than the brown adipose MAO in both groups of mice. While there was no appreciable difference in the MAO activities of brown adipose tissues between obese and lean mice, the enzyme from the white adipose tissue of obese mice had a higher specific activity than that of the lean mice. The higher MAO activity in white adipose tissue was observed when tyramine or serotonin was employed as substrate but not with benzylamine. Examination of mitochondrial MAO from epididymal adipocytes revealed marked differences in the properties of the enzyme between whole adipose tissue and isolated adipocytes. The inhibition characteristics of MAO from these tissues were studied with the specific inhibitors clorgyline and deprenyl.     

Diagnosis and Treatment of Amanita Phalloides-Type Mushroom Poisoning: Use of Thioctic Acid

The number of cases of mushroom poisoning is increasing as a result of the increasing popularity of “wild” mushroom consumption. Amanitin and phalloidin cytotoxins found in some Amanita and Galerina species produce the most severe and frequent life-threatening symptoms of Amanita phalloidestype poisoning. Delay in onset of symptoms, individual susceptibility variation and lack of rapid and reliable identification have contributed to the significant morbidity and mortality of this type of poisoning.A rapid chromatographic assay for identifying the potent cytotoxins and apparently successful management using thioctic acid of two cases of A. phalloides-type mushroom poisoning are reported. All known cases of A. phalloides-type mushroom poisoning treated with thioctic acid in the United States are summarized.