The hypocalcemic response to protamine as a measure of bone resorption

The heparin antagonist protamine inhibits bone resorption. In the present study protamine was given i.v. at a dose of 10 mg/kg to goats and sheep in various stages of pregnancy and lactation. It is known that bone resorption increases as pregnancy progresses. In sheep maximum in bone resportion is reached at early lactation. The hypocalcemic response to protamine followed a similar course. The slightest decrease in serum calcium was obtained during early pregnancy and the greatest during late pregnancy and early lactation. Protamine increased serum inorganic phosphorus. The increase was most pronounced during early pregnancy. Protamine did not significantly change serum magnesium.Five lactating ewes were given 25000 i.u./kg of vitamin D3. Serum calcium increased and the hypocalcemic response to protamine was greater after vitamin D₃ administration than before.The results showed that the hypocalcemic response to protamine can be used as an indicator of the role of bone resorption in calcium homeostasis in various physiological situations.     

鲤鱼精蛋白的提取与抗菌稳定性研究

该文研究了采用超声波技术提取鲤鱼抗菌精蛋白的工艺条件和抗菌稳定性。实验结果表明：采用超声波技术提取鱼精蛋白硫酸用量少，提取时间短。用1.0A强度的超声波和5%的硫酸溶液提取鱼精蛋白，提取时间20 min，能得到较高活性的鲤鱼抗菌精蛋白。并进一步研究了pH值、温度、金属离子和蛋白酶对鲤鱼精蛋白抗菌活性的影响。     

鱼精蛋白的抑菌机理

鱼精蛋白对细菌呼吸系统能产生微弱的抑制作用，但这并不是其抑菌活性的主要途径；鱼精蛋白主要是以分子中多聚精氨酸或多聚精氨酸与其它少数几个氨基酸以某一种结构或形式和细菌细胞壁结合，破坏细胞壁的形成，从而达到其抑菌效果。     

Factors affecting the hypocalcaemic response to protamine.

The hypocalcaemic response to protamine, as a measure of bone resorption rate, was studied in cattle and sheep. Three groups of calves were studied (1–3 days, 2–3 weeks and 4 months old). The oldest calves showed the greatest response, indicating a more rapid skeletal turnover in these animals, probably related to a higher growing rate. A group of cows was tested at 2 occasions, near parturition and 2–3 weeks after parturition. The decrease in plasma calcium was small near parturition, while a profound drop was obtained 2–3 weeks post partum, which supports earlier findings that bone resorption is more or less blocked in parturient cows. Young pregnant ewes showed the same degree of hypocalcaemia as adult pregnant ewes but the recovery was more rapid in the young animals. Young rams were given protamine before and after diethylstilboestrol treatment. No differences in calcium response were obtained. Varying plasma phosphate responses were obtained. A pronounced hyperphosphataemia was found in the adult pregnant ewes. Diethylstilboestrol caused hypermagnesaemia in the rams.     

理化因素对鱿鱼鱼精蛋白抑菌性的影响

选用鱿鱼精巢组织为原原料,经水解,抽提,沉淀等一系我方法得到鱿鱼鱼精蛋白样品。后经葡聚糖凝胶对其进行过滤层析,可得纯度较高的鱿鱼鱼精蛋白,最后对照讨论了各种理化因素如温度,盐离子浓度,酸度,有机成份等对鱿鱼鱼精蛋白抑菌性的影响,同时测定了其在不同影响因素下的最低抑菌浓度。     

Proliferative glomerulonephritis in experimental Leishmania donovani infection of the golden hamster

Extensive kidney involvement is reported in golden hamsters infected with Leishmania donovani. The lesion is characterised grossly by pale and enlarged kidneys, and histologically by thickening of the basal lamina of the glomerulus, distended convuluted tubules containing protein casts, constricted glomerular capillaries and infiltration of the interstitial tissues with mononuclear cells. Quantitative measurement of the glomerular cells labelled in vivo with tritiated thymidine showed a striking increase in the glomerular cell proliferation as the infection progressed. Using direct immunofluorescent technique, granular deposits of IgG, complement C₃ and fibrinogen were detected in the glomeruli of the infected animals. A positive protamine sulphate test, as well as histological evidence, showed that disseminated intravascular coagulation had occurred in the infection. Although the antigens have not been identified, antigen-antibody complexes are strongly implicated in the pathogenesis of the proliferative glomerulonephritis observed in this study.     

鱼精的研究与开发

综述了鱼精精巢提取脱氧核糖核酸(DNA)和碱性蛋白质(鱼精蛋白)的研究与开发进展，并重点介绍了鱼精蛋白的研究历史、物理和化学及生物化学特性、制备和纯化、应用及抑菌机理等。     

Inactivation of Heparin by Cationically Modified Chitosan

This study was performed to evaluate the ability of N-(2-hydroxypropyl)-3-trimethylammonium chitosan chloride (HTCC), the cationically modified chitosan, to form biologically inactive complexes with unfractionated heparin and thereby blocking its anticoagulant activity. Experiments were carried out in rats in vivo and in vitro using the activated partial thromboplastin time (APTT) and prothrombin time (PT) tests for evaluation of heparin anticoagulant activity. For the first time we have found that HTCC effectively neutralizes anticoagulant action of heparin in rat blood in vitro as well as in rats in vivo. The effect of HTCC on suppression of heparin activity is dose-dependent and its efficacy can be comparable to that of protamine-the only agent used in clinic for heparin neutralization. HTCC administered i.v. alone had no direct effect on any of the coagulation tests used. The potential adverse effects of HTCC were further explored using rat experimental model of acute toxicity. When administered i.p. at high doses (250 and 500 mg/kg body weight), HTCC induced some significant dose-dependent structural abnormalities in the liver. However, when HTCC was administered at low doses, comparable to those used for neutralization of anticoagulant effect of heparin, no histopathological abnormalities in liver were observed.