The liver slice system: A rapid in vitro acute toxicity test for primary screening of hepatotoxic agents

A simple method for the rapid screening of hepatotoxic agents is described. Liver slice systems were prepared from rats and mice, and incubated in Krebs-Ringer-Hepes medium with different concentrations of the test compounds. Hepatotoxicity was monitored by determination of liver enzymes in the slice medium. Enzyme leakage was dose- and time-dependent. Histopathological changes in the hepatotoxin-treated slices were well correlated with the extent of enzyme leakage. Species differences in susceptibility to various hepatotoxins could be easily detected by this in vitro system: the dose-toxicity curves revealed that the mouse is more vulnerable than the rat to acetaminophen and furosemide. These findings are well correlated with those of in vivo experiments. A preliminary study showed that, in the same species, the relative toxicities of various chemicals in the liver slice system were similar to those reported in vivo. In summary, these results on the tissue slice system are encouraging. However, much more work will have to be done before the system can be considered sufficiently well validated for routine use.     

Architectural alterations in rat cerebral microvessels after hypobaric hypoxia

We performed 3-dimensional studies of vascular casts of the microvasculature of the cerebral cortex of rats that were exposed to three weeks of hypobaric hypoxia and of control rats. Scanning electron microscopy of the casts gave the qualitative impression of increased vascularity of the cerebral cortex, particularly the deeper layers, in hypoxic rats. Quantitative analysis of capillary segment lengths revealed a significant shift in the frequency distribution to longer lengths (from 77 ± 8 to 90 ± 14 μm) in the deep, but not in the superficial, layers of the cerebral cortex of hypoxic rats. These findings agree with previous results reporting increased capillary density in the brain after exposure to prolonged hypobaric hypoxia and suggest that capillary segment elongation plays a role in the increased capillary density in the deeper layers of the cerebral cortex.     

Mutation analysis of Jewish hunter patients in Israel

We have performed molecular and mutation analyses on 14 unrelated Israeli Hunter families and have identified the IDS mutation in 8 of them. Three unrelated Ashkenazi patients had the same previously reported mutation (1246 C→T). Based on the haplotypes of the mutation-bearing chromosomes, we concluded that this is a recurrent mutation. In two patients, we identified a deletion spanning exons V–VII. Three novel mutations were observed in different patients: L410P, 717del4, and 244del3. In addition, the silent mutation (562 C→T) was observed in one patient. © 1994 Wiley-Liss, Inc.     

Severe Chlamydia trachomatis pneumonia in a patient with no immune deficiency

A 40-year-old patient with no immune deficiency was admitted because of severe bilateral pneumonia and pleural effusion. The diagnosis of Chlamydia trachomatis pneumonia was confirmed by isolation of the pathogen and the appearance of serum antibodies to Chlamydia species.     

微晶蜡非催化氧化反应的神经网络模型

对微晶蜡进行了非催化空气氧化，并利用人工神经网络将氧化微晶蜡的酸值、酯值及微晶蜡的氧化条件（反应温度、空气流量和反应时间）进行关联，建立了微晶蜡非催化氧化的酸值、酯值的神经网络模型，并用该模型预测了反应条件对微晶蜡氧化反应过程的影响。结果表明，该模型不但具有较高的计算精度，而且具有满意的预测能力。