黑河上蔡段河水及饮用水的致突变性

目的：探讨黑河上蔡段癌症高发区河水及饮用水的致突变性。方法：采集严重污染的黑河河水及沿岸浅井水分别进行以下试验。①用ＸＡＤⅡ树脂提取各水样中的有机提取物作为待测样品,以呋喃基康酰胺和叠氮钠作阳性对照,以自发回变率为阴性对照,用鼠伤寒沙门氏菌属ＴＡ９８ 、ＴＡ１００ 菌株进行Ａｍｅｓ 试验。以突变比ＭＲ 值评价试验结果。②松滋青皮蚕豆温浸芽约２ ｃｍ ,分别取３ ～４ 粒放入不同水样中处理,同时以蒸馏水、郑州市自来水作阴性对照,环磷酰胺（１ ｍｇ／Ｌ） 作阳性对照进行微核试验。显微镜下观察根尖细胞微核数,统计微核千分率（ＭＣＮ‰） 。结果：①河水有机提取物对ＴＡ９８、ＴＡ１００ 菌株均可诱发阳性回变;②沿岸浅井水有机提取物能诱发ＴＡ９８菌株的阳性回变;③河水、井水均可致蚕豆根尖细胞微核率（ＭＣＮ‰） 明显增高。④浅井水和河水的致突变性及毒性（ 抑菌圈直径大小） 基本相同。结论：①由于浅井水和河水的致突变性及毒性基本相同,故浅井水中的致突变物质可能来源于河水的水平渗透;②沿岸居民癌症高发与河水污染的潜在致癌性有密切关系,应予以高度重视     

Intracellular ATP depletion inhibits swelling-induced -[H]aspartate release from primary astrocyte cultures

Volume expansion-sensing outward rectifier (VSOR) anion channel, also referred to as volume-sensitive organic osmolyte-anion channel (VSOAC), appears to be responsible for cell swelling-induced amino acid release in a variety of cells. One prominent feature of the VSOR/VSOAC is that non-hydrolyzed intracellular ATP binding to the channel or an accessory protein is required for its activation. In this study, the effect of intracellular ATP depletion on the swelling-induced release of -[³H]aspartate from rat primary astrocyte cultures due to exposure to either high K⁺ or hypotonic media was studied. When the cells were pretreated for 10 min with a combination of the metabolic inhibitors 2-deoxyglucose and rotenone, 100 mM K⁺ media- or hypotonic media-induced -[³H]aspartate release was completely suppressed. Added separately, each inhibitor showed only partial or no inhibition of -[³H]aspartate release, which correlated with its relative effectiveness in decreasing intracellular ATP levels. These data are consistent with the view that during high [K⁺]_o or hypotonic media-induced swelling of primary astrocyte cultures an ATP-dependent swelling-activated VSOAC channel is responsible for -[³H]aspartate release and close to normal ATP is required for full channel activation.     

Neurological prognosis correlated with variations over time in the number of subependymal nodules in tuberous sclerosis

In tuberous sclerosis (TS), brain CT reveals subependymal nodules, cortical tubers and white matter lesions. This study is a retrospective analysis of the relationship between the variations over time in the number of subependymal nodules and the clinical course in cases of tuberous sclerosis. Twenty-four children with tuberous sclerosis, who attended the National Children's Hospital as outpatients, were followed by means of brain CT examinations for 7 years and 1 month on average. Cranial MRI was also performed in 22 cases. Brain CT disclosed subependymal nodules already in early infancy. In almost all cases, the number of subependymal nodules gradually increased with age, especially around the frontal horn of the lateral ventricle. The increase stopped at around age 10. The cases with five or more subependymal nodules at the initial or subsequent CT examination (17 patients; Group A) exhibited a significantly greater number of cortical tubers than those with less than five (five patients; Group B) and had white matter lesions unlike Group B. In addition, the number of cases with either infantile spasms or mental retardation was significantly higher in Group A than Group B (P<0.005). In conclusion, the number of ventricular subependymal nodules may allow prediction of the severity of the cerebral dysfunction in TS. Our results suggest that its variation may reflect the degree of the embryologic disorder when neuronal cells grow in the early gestational period.     

中药川芎中无机阴离子和有机酸成分的研究

目的：研究中药川芎中有机酸和无机阴离子的同时分析方法。方法：采用非抑制型阴离子交换色谱法,色谱柱为ＳｈｉｍｐａｃｋＩＣＡ１,流动相为０８ｍｍｏｌ·Ｌ－１邻苯二甲酸氢钾。结果：川芎提取液中３种有机酸和３种无机阴离子得到了较好的分离。结论：该方法分析速度快,准确,灵敏度高。     

Long-term average suspended particulate concentrations in Smokers' homes

Summary Suspended particulate matter (SPM) concentrations were measured in about 100 homes in the city of Arnhem, The Netherlands. Most homes were sampled for 2 months continuously. Monthly average SPM concentrations ranged from 20–570 g/m³. From 26 houses, smoking data were gathered at a later date. A clear relationship was found between SPM concentrations and number of smokers in the home.     

Characteristics of epilepsy in severely mentally retarded individuals

In order to clarify the characteristics of epilepsy in patients with severe mentally retarded (SMR) subjects, we analyzed 52 SMR subjects with epilepsy from the institute for SMR subjects at Kikuchi National Hospital, Kumamoto, Japan. A total of 61.5% patients had uncontrolled seizures which were resistant to treatment. The most common combinations of seizure types in those not responding to conventional anticonvulsants were generalized tonic-clonic seizures (GTCS) with tonic seizure and GTCS with atypical absence. Their clinical features were characterized by spastic paralysis associated with a slower background electroencephalogram and abnormal computed tomography scans of the head, suggesting the involvement of cortical damage. These findings suggest that a large proportion of epilepsy in SMR subjects does not respond to treatment and that the severity of organic brain damage may therefore affect the natural course of epilepsy in such patients.     

Delayed transient neurologic toxicity due to tacrolimus: CT and MRI

We report a case of transient neurologic toxicity secondary to tacrolimus. The clinical and imaging findings are reported and their subsequent regression after interruption of therapy in the patient following a bone-marrow transplant is also described. The etiology of the neurotoxicity and its analogy with other immunosuppressant agents are discussed. Received: 18 June 1999/Accepted: 14 December 1999     

Inhaled environmental combustion particles cause myocardial injury in the Wistar Kyoto rat.

Epidemiologists have associated particulate matter (PM) air pollution with cardiovascular morbidity and premature mortality worldwide. However, experimental evidence demonstrating causality and pathogenesis of particulate matter (PM)-induced cardiovascular damage has been insufficient. We hypothesized that protracted, repeated inhalation by rats of oil combustion-derived, fugitive emission PM (EPM), similar in metal composition to selected sources of urban air PM, causes exposure duration- and dose-dependent myocardial injury in susceptible rat strains. Zinc was the only primary water-leachable/bioavailable element of this EPM. Male Sprague-Dawley (SD), Wistar Kyoto (WKY), and spontaneously hypertensive (SH) rats were exposed nose-only to EPM (2, 5, or 10 mg/m(3), 6 h/day for 4 consecutive days or 10 mg/m(3), 6 h/day, 1 day/week for 4 or 16 consecutive weeks). Two days following the last EPM exposure, cardiac and pulmonary tissues were examined histologically. The results showed that particle-laden alveolar macrophages were the only pulmonary lesions observed in all three rat strains. However, WKY rats exposed to EPM (10 mg/m(3) 6 h/day, 1 day/week for 16 weeks) demonstrated cardiac lesions with inflammation and degeneration. To further characterize the nature of EPM-associated lesions, more rigorous histopathological and histochemical techniques were employed for WKY and SD rats. We examined the hearts for myocardial degeneration, inflammation, fibrosis, calcium deposits, apoptosis, and the presence of mast cells. Decreased numbers of granulated mast cells, and multifocal myocardial degeneration, chronic-active inflammation, and fibrosis were present in 5 of 6 WKY rats exposed to EPM for 16 weeks. None of these lesions were present in WKY exposed to clean air. EPM-related cardiac lesions were indistinguishable from air-exposed controls in SD and SH rats. This study demonstrates that long-term inhalation exposures to environmentally relevant PM containing bioavailable zinc can cause myocardial injury in sensitive rats. These findings provide supportive evidence for the epidemiological associations of cardiovascular morbidity and ambient PM.     

有机化学中的学习障碍及教学策略

通过对学生在有机化学学习过程中的障碍分析，实施相应的教学策略，以提高有机化学的教学质量和学生的学习水平。     

Effect of long-term vigabatrin administration on the immature rat brain

PURPOSE: To determine whether the neuropathologic changes produced by vigabatrin (VGB; gamma-vinyl GABA) administration in the developing rat brain are reversible. METHODS: We injected rats daily with VGB (25-40 mg/kg/day, s.c.) from age 12 days for 2 weeks followed by 2 weeks of a drug-free period. Behavioral testing, magnetic resonance (MR) imaging, biochemical assays, and histologic technique were used to assess the adverse effect of VGB in developing brain and its reversibility. RESULTS: At the end of 2 weeks' VGB administration: (a) there was a hyperactivity and a shortened latency to escape out of cool water; (b) white matter appeared hyperintense in T2 and diffusion-weighted MR images with 4-15% increases in T2; (c) microvacuolation, TUNEL-positive nuclei, and swollen axons were observed in the corpus callosum; (d) myelin staining indicated a reduction in myelination, as did the reduction in activities of myelin and oligodendrocyte-associated enzymes and the decrease in myelin basic protein on Western blots. Two weeks after stopping VGB administration: (a) MR images were normal, and microvacuolation was no longer in the white matter; (b) reduction in myelination reversed partially; (c) the T2 relaxation time remained elevated in the hypothalamus; and (d) the behavioral response remained abnormal. CONCLUSIONS: Long-term VGB administration to young rats causes brain injury, which recovers partially on its cessation. The observed cell death, disrupted myelination, and alterations in behavior indicate a need for further safety assessment in infants and children.