小鼠腹腔注射阿霉素诱导骨髓细胞微核率的最佳时间—剂量效应分析

目的：寻找一次染毒条件下,腹腔注射阿霉素诱导小鼠骨髓细胞微核率出现峰值的时间-剂量条件。方法：将150只小鼠随机分为5组,每组30只,雌雄各半。腹腔注射,1次给药,对照组给生理盐水,处理组的阿霉素剂量分别是2.5 mg/kg、5 mg/kg、10 mg/kg和20 mg/kg。染毒18 h、24 h、30 h、48 h和72 h后取小鼠骨髓进行微核分析,评价阿霉素对小鼠的遗传毒性作用。结果：理想的腹腔注射诱导的小鼠骨髓细胞微核率峰值的条件就是：一次染毒,阿霉素剂量在10%LD50即2.5 mg/kg至80%LD50即20 mg/kg的范围内剂量越大微核率越高,取样时间在30~48 h间微核率最高。     

Dual role of endogenous nitric oxide in tumor necrosis factor shock: induced NO tempers oxidative stress

Tumor necrosis factor (TNF) is involved in pathologies like septic shock, inflammatory bowel disease and rheumatoid arthritis. TNF and lipopolysaccharide can incite lethal shock, in which cardiovascular collapse is centrally orchestrated by the vasodilating free radical nitric oxide (NO). However, NO synthase (NOS) inhibition causes increased morbidity and/or mortality, suggesting a dual role for NO. To investigate the potential protective role of NO during TNF shock, we treated mice with TNF with or without NOS inhibition. Experiments in endothelial- NOS- and inducible NOS-deficient mice identified inducible NOS as the source of protective NO. Distinctive TNF-induced lipid peroxidation, especially in liver and kidney, was aggravated by NOS inhibition. In addition, various antioxidant treatments and a phospholipase A2 (PLA2) inhibitor prevented sensitization by NOS inhibition. Together, these in vivo results indicate that induced NO not only causes hemodynamic collapse, but is also essential for curbing TNF-induced oxidative stress, which appears to hinge on PLA2-dependent mechanisms.Received 29 March 2005; received after revision 29 April 2005; accepted 24 May 2005     

Sperm enzyme activity analysis in individual sperm for detection of heritable mutations in mammals

Summary Male mice were injected i.p. with 2.5 mg/kg mitomycin C, 100 mg/kg ethyl nitrosourea or saline and mated with untreated virgin females five weeks later. Sperm from 64 of the F₁ male progeny were analyzed histochemically for acrosin, succinic dehydrogenase and alpha-glycerophosphate dehydrogenase activity. The frequency of F₁ males with sub-normal sperm enzyme activity was significantly higher among progeny from treated males than in controls. These results show that analysis of sperm enzyme activity in F₁ males is a practical method for detection of transmitted mutations induced in a treated parent.We gratefully acknowledge USPHS, NIEHS grant 1 RO1 ES02607-02 and technical assistance by G. M. Oldford.     

臭氧对小白鼠生长及学习行为影响的初步研究

本实验用0.50——1.00ppm 浓度的臭氧处理小白鼠66小时。实验结果初步表明:小白鼠在接受臭氧处理后,体重增长较缓,条件反射活动不易建立,学习能力明显地低于对照组。     

伯氏疟原虫感染小白鼠剂量的初步观察

用不同剂量的伯氏疟原虫接种小白鼠,目的在于建立实验动物模型。以较小剂量如1×10~3个感染疟原虫的红细胞接种,出现原虫血症的小鼠仍可达100％。当以较小剂量接种时,原虫血症出现较迟,小白鼠存活的时间可以延长。原虫血症出现后,所有小白鼠最后均死亡,而不能自行痊愈。由于使用的小白鼠数目太少,仅作初步简报。     

The effect of nicotine on blood pressure in the genetically hypertensive mouse

Summary Mice genetically selected for high and low blood pressure were exposed to nicotine via a single injected dose or addition to drinking water for 52 weeks. In the acute study, the response of mice with high blood pressure was a statistically significant increase in blood pressure. In the chronic study the pattern of response to nicotine ingestion was similar for mice with high blood pressure and those with low. Both lines responded with an increase in blood pressure after 6 weeks followed by a decrease to below baseline blood pressure at 12 weeks.This research was supported in part by an allocation from the General Research Fund of the University of Kansas.     

SX1近交系小鼠主要脏器及血液生化指标的测定

目的测定SX1近交系小鼠的主要生化及血液指标,为建立该品系小鼠的生物学特性资料提供实验数据。方法从F29、F30代仔鼠中选择1、2、3、4月龄的小鼠,分别测定这些小鼠的体重、体长、尾长;心、肝、脾、肺等12种脏器的重量;总蛋白、白蛋白、血糖、肌苷等16项血液生化指标及白细胞、红细胞、血红蛋白等15项血液常规指标。结果SX1小鼠在1、23、、4月龄时的体重、体长、尾长,心、肝、脾等脏器随小鼠生长而增加,但胸腺随小鼠生长而缩小;各脏器重量均雄性大于雌性,肾上腺为雌性大于雄性;其中14项血液生化指标随小鼠的生长基本无明显变化,而总胆红素和碱性磷酸酶指标随小鼠生长而降低,多数指标无性别差异,但碱性磷酸酶指标雌性大于雄性;其中13项血液常规指标随小鼠的生长基本无明显变化,只有白细胞与平均血小板压积随小鼠生长而降低,且白细胞指标雄性大于雌性。结论各项指标基本符合近交系小鼠的特征,补充了SX1近交系小鼠的资料。