树鼩(Tupaia belangeri chinensis)精子发生的细胞学观察

对8只成体树鼩的睾丸进行了精子发生的细胞学和动力学观察。精原细胞可区分为A型和已分化定向的B型。生精上皮周期可分为12个连续阶段,不同阶段典型的细胞组合可被辨认。各阶段的相对持续时间以阶段Ⅴ、Ⅵ、Ⅶ的比率最高,分别为11.43,18.88、15.44;阶段Ⅸ、Ⅹ最低,为3.78和3.87。A型精原细胞在各阶段的数量分布并不保持恒定,阶段Ⅵ—Ⅷ和阶段Ⅸ时,分别出现两次成倍增长。B型精原细胞和前细线期精母细胞与每100个足细胞之比的平均值,在阶段Ⅰ、Ⅴ、Ⅶ分别为28.89、76.98、196.91。精细胞经14步变态为成熟精子。精子形成过程中顶体发育的形态学变化及成熟精子的形态,与灵长类动物相比具有较多的类似之处;而同啮齿类动物相比,存在明显的形态差异。     

国人坐骨大切迹的测量与性别判别分析

本文对614件(男358件女256件)国人坐骨大切迹进行了八项测算。对坐骨大切迹在性别鉴定上的作用进行了探讨。     

Serum Albumin Washing Specifically Enhances Arachidonate Incorporation into Synaptosomal Phosphatidylinositols

Arachidonate incorporation into synaptosomal phospholipids was shown to be affected by factors including the procedure for preparation of the membrane fractions and preincubation of synaptosomes prior to assay of incorporation of arachidonate into both phosphatidylcholine (PC) and phosphatidylinositol (PI). However, the inhibition toward incorporation into PIs, but not PCs, was fully reversed when the membranes were washed with bovine serum albumin. A twofold increase in arachidonate incorporation into PIs was also observed when freshly prepared synaptosomes were washed with serum albumin immediately before assay of incorporation activity. The inhibitory action is thought to be due to an increase in polyunsaturated fatty acids and/or their oxidation products which may then elicit a special effect on the acyltransferase responsible for transferring arachidonate into phosphatidylinositols. The differences in fatty acid uptake and response to serum albumin also suggest the presence of different acyltransferase for acyl transfer to PIs and PCs.     

Detergent Effects on the Phosphatidylinositol-Specific Phospholipase C in Rat Brain Synaptosomes

In the presence of Ca2+ (2.5 mM) and using [14C]arachidonoyl phosphatidylinositol (PI) membrane as substrate, phosphatidylinositol-specific phospholipase C (PI-PLC) (EC 3.1.4.10) in rat brain synaptosomes was activated by deoxycholate but not taurocholate. Calcium stimulated enzymic hydrolysis by both detergents, but the stimulatory effect of taurocholate was less than that of deoxycholate. Peak stimulation for deoxycholate was observed at 1 mg/ml, whereas that for taurocholate was 4 mg/ml. When 1 mM EDTA was added to the taurocholate (4 mg/ml) and Ca2+ (3.5 mM) system, synaptosomal PI-PLC activity was greatly stimulated, to almost the same level as the deoxycholate + Ca2+ system. This system required the presence of all three factors, and EGTA could not effectively replace EDTA in the stimulatory action. The detergent-induced hydrolysis of synaptosomal PI by the deoxycholate + Ca2+ and the taurocholate + Ca2+ + EDTA systems was strongly inhibited by divalent metal ions such as Zn2+, Cu2+, Pb2+, and Fe2+, whereas Mg2+ and Ca2+ were ineffective. Nevertheless, only the deoxycholate + Ca2+ system was responsive to enzyme inhibition by membrane-perturbing agents such as lysophospholipids and free fatty acids. The specific requirement for EDTA in the taurocholate system may be due to the release of a pool of inhibitory divalent metal ions from the membranes.     

THE METABOLISM OF PALMITIC ACID IN THE PHOSPHOLIPIDS, NEUTRAL GLYCERIDES AND GALACTOLIPIDS OF MOUSE BRAIN

Abstract— Following intracerebral injection, [¹⁴C]palmitic acid was rapidly incorporated into a variety of brain lipids. After 12 hr, 78 per cent of the lipid radioactivity was in phospholipids, 15 per cent was in triacylglycerols, 1 per cent each was in free fatty acids and galactolipids, and the remainder was in other neutral glycerides. Over 65 per cent of the phospholipid radioactivity was found in the choline phosphoglycerides but this proportion decreased substantially with time. At later times, increasing portions of the radioactivity were present in the monounsaturated acyl groups and the alkenyl groups but no radioactivity was detected in cholesterol or polyunsaturated acyl groups. These results indicate that most of the extensive recycling of radioactivity took place without oxidative degradation of the palmitoyl groups. The relative rates of incorporation of radioactivity were compared at 12 hr after injection. The specific radioactivities of the serine, ethanolamine, and choline phosphoglycerides had ratios of 6:3:2 based on the palmitoyl group content and 1:2:4 based on their phosphorus content. The specific radioactivities of galactolipids with O -acyl groups were higher than the specific radioactivitiesof cerebrosides or cerebroside sulphates. A new solvent mixture for thin-layer chromatography of brain galactolipids was described (chloroform-acetone-methanol-water, 60:20:20:1, by vol.).