Variations in peroxisomal catalase of neonatal rat hepatocyte subpopulations

Alcohol consumption during pregnancy is teratogenic and induces severe alterations in hepatocytes. In the hepatocyte peroxisomal system, ethanol is converted in the presence of H₂O₂ to acetaldehyde and water. Therefore, peroxisomal catalase also acts as an antioxidant defence mechanism by removing H₂O₂ and preventing the formation of hydroxyl radicals in the cell. Alterations in peroxisomal catalase after pre- and pre+postnatal alcohol exposure were investigated in the rat. The effect of pre- and postnatal exposure to ethanol on hepatocyte subpopulations was analysed in isolated hepatocytes originating from periportal, intermediate and perivenous zones. Analysis of catalase revealed that the total activity and content of this enzyme were higher in 12-day-old cells than in cells from newborns and that this increment was more pronounced in treated cells. In controls, the amount of peroxisomal catalase increased mainly in periportal cells, whereas alcohol exposure induced a significant increase in the catalase of perivenous hepatocytes. We conclude that pre- and postnatal alcohol exposure mainly affects the perivenous hepatocyte peroxisomes and that the increase in peroxisomal catalase could constitute a defence mechanism against free radical generation induced by alcohol exposure during the perinatal period.     

Carbon Monoxide Mass Exposure in a Pediatric Population

Abstract. Objectives:To describe the outcomes of a mass carbon monoxide (CO) intoxication, and to calculate the CO half-life in a pediatric school-aged population.
Methods:A retrospective chart review was performed based on Regional Poison Center database information, hospital laboratory data, and medical records of the pediatric patients who sought care at one of 3 St. Louis area hospitals, after exposure to high levels of CO. Exposures occurred on January 5, 1996, after evidence of a CO leak was discovered at an area elementary school. Charts were reviewed for major demographics, symptoms reported, carboxyhemoglobin (COHb) levels and times, and level of effect.
Results:Information about 177 (35%) of the 504 children in attendance at school that day was available. Mean age was 8.7 ± 1.8 years (range 4–12 years). Symptoms were present in 155 (88%) of the 177 children for whom data were available. Initial COHb levels were obtained for 147 (83.1%) of the 177 children. First mean COHb level was 7.0% (95% CI = 6.6–7.5%). Second COHb level was obtained for 26 children with a mean of 2.7% (95% CI = 2.2–3.2%). Calculated half-life of COHb, on 100% 0₂ at 1 atm, was 44.0 minutes (95% CI = 39.6–48.2 minutes).
Conclusion:Some children had symptoms at COHb levels that traditionally have been considered nontoxic. The elimination of COHb was found to be more rapid in this population of children than reported in other studies.     

Recombinant fowlpox virus inducing protective immunity in non-avian species

The natural host of fowlpox virus is limited to avian species. When inoculated into non-avian tissue culture cells, however, fowlpox virus can initiate an abortive infection. A fowlpox virus was engineered to express rabies virus glycoprotein. On inoculation of the recombinant virus into either avian (permissive) or non-avian (non-permissive) cells, the rabies glycoprotein was expressed as a membrane-associated antigen. Inoculation of the fowlpox virus recombinant into six different species of mammal resulted in specific immune responses to both fowlpox antigens and to rabies glycoprotein. In mice, cats and dogs the immune response was sufficient to protect against a live rabies virus challenge. The results demonstrate the utility of a fowlpox virus vector in immunizing non-avian species against rabies in the absence of productive viral replication of the fowlpox vector.     

The use of experimental studies to reveal suspected neurotoxic chemicals as occupational hazards: acute and chronic exposures to organic solvents.

The nervous system differs from many other body organs by its central control of vital functions and its low regeneration capacity. Organic solvents have, as a group, been suspected to have neurotoxic effects. Because of their similar physical properties and the fact that in industrial uses, they are often present in various mixtures, organic solvents have also been regarded, unfortunately, to induce common neurotoxic effects. However, it is evident from experimental studies using specified exposure conditions that different organic solvents have very diverse neurotoxic effects and also that the toxic mechanism may differ between acute and chronic exposure. No specific method used to describe a neurotoxic effect or single toxic response can be used for the overall occupational risk assessment of all organic solvents. Each solvent has to be considered as having its own unique toxic effects.     

110例嗜酸细胞增多性非变应性鼻炎的液氮冷冻治疗

１１０例嗜酸细胞增多性非变应性鼻炎的液氮冷冻治疗山西医学院第二附属医院（０３０００１）牛玉梅，刘学仁按Ｍｇｇｉｎｄ将常年性鼻炎分为三类：一类常年性变态反应性鼻炎；二类非变态反应性鼻炎伴鼻分泌物嗜酸细胞增多综合征也叫嗜酸细胞增多性非变态反应性鼻炎（Ｅｏｓｉｎｏｐｈｉｌｉｃｎｏｎａｌｌｅｒａｉｃｒｈｉｎｉｔｓ，ＥＮＲ）；三类自主神经性常年性鼻炎［１］。我们将ＥＮＲ中找不到致敏物，而与冷热空气有关与情绪无关的１１０例患者进行了液氮冷冻治疗。临床资料８０２例常年性鼻炎患者进行皮肤激发试验。４３７例找出了致敏物，进行特异性过敏诱因脱敏治疗或抗过敏药物治疗。３６５例试验阳性，其中有１３５例与冷热空气有关。ｌｌ０例行冷冻治疗。１ｌ０例中男５０例，女６０例；年龄最大６５岁，最小１６岁。１１０例均有间歇性的连续喷嚏发作，浆液性或粘液性鼻分泌物增多和鼻粘膜非充血性肿胀引起的堵塞，无因吸入致敏原诱发症状的病史；血清ＩｇＥ值不升高，特异性皮肤试验结果为阳性；鼻分泌物中嗜酸细胞阳性。方法：先将鼻腔内喷入１％地卡因溶液３次粘膜表面麻醉，用卷好的４厘米长、０．４～０．６厘米粗的棉棒沾上液氮在鼻镜直视下迅速插入鼻腔内。时间约１分钟左右（冷     

PM2.5混悬液染尘大鼠肺银染色的组织病理学观察

目的观察PM2.5混悬液染尘大鼠的肺组织病理学改变及银染色显示肺内尘粒的效果。方法将收集的游离PM2.5制成混悬液，72只Wistar大鼠随机分为低剂量组（每0．2ml含PM2.50．3nag）、中剂量组（每0．2ml含PM2.50．75mg）、高剂量组（每0．2ml含PM2.52mg）和对照组，每组18只。3个实验组分别以不同的剂量采用支气管肺内滴入方式染尘，每周染尘1次。分别于染尘后第4、12及24周时，取肺脏，石蜡包埋组织切片进行HE染色及沃森一斯塔理（Worthin-Starry，WS）银染色观察、透射电镜（TEM）观察，对肺内尘粒进行X-线质谱元素分析（X-RSA）。计数大鼠肺内肉芽肿样病变的数目，测定肺内尘粒的沉积程度、平均积分吸光度值（IOD）和平均积分面密度值（IAD）。结果随着染毒时间的延长和染毒剂量的增大，大鼠肺内肉芽肿样病变的数目及其细胞质内尘粒的IAD值和IOD值也逐渐增高。这些尘粒在WS染色切片上呈黑褐色，更清晰；其IOD值和IAD值均明显高于HE染色下的测定值，差异有统计学意义（P〈0．05）；尘粒IOD值与肉芽肿病变数目呈正相关关系（r=0．639，P〈0．01）。TEM下大鼠肺内尘粒的超微结构与游离的PM2.5相同，X-RSA分析两者的主要元素成分也相同，均为硅元素。结论PM2.5混悬液染尘可以引起大鼠肺内出现肉芽肿样病变，WS银染色方法可以较好地显示被吞噬细胞吞噬后的PM2.5，其染色效果优于HE染色。     

硝普钠对慢性染铅鼠脑组织中NO、SOD、MDA含量水平的影响

目的 :观察硝普钠对慢性染铅鼠脑组织中NO、SOD、MDA含量水平的影响 .方法 :建立慢性染铅鼠模型 ,隔日灌服醋酸铅 ,约 4周 ,观察给药 (硝普钠 )后 3h、12h、2 4h脑组织中NO、SOD、MDA的变化。结果 :实验组NO含量升高 ,SOD活性增强 ,MDA的含量下降 ,各观察时点均与模型组存在显著性差异 (p <0 .0 1)。结论 :给予外源性硝普钠后 ,脑组织脂质过氧化反应减低 ,提示硝普钠对慢性铅中毒鼠脑组织损伤具有保护作用。     

对Hazelton等提出的云锡矿工肺癌主要危险来自砷的商榷

Using two-stage clonal expansion model with data-base provided by Lubin, WD Hazehon et al indicated the high risk of arsenic, but not radon, in the etiology of Yunnan tin miner' s lung cancer. The author of this review iterated the problems in the data-base of Lubin,and considered that it may result in low estimate for the risk of radon in paper of Hazehon et al. Attributable risk was estimated by them with changing exposure patterns of each individual, but the efficacy of this two-stage model will be violated by the invariability of appointed radon/arsenic exposures. Risk comparison was used to distinguish the contribution from radon/arsenic, which was hampered by the high correlation between their joint exposures. As Lubin, Hazehon et al neglected the confounding from environmental arsenic pollution in early years. From all of above, their viewpoint is worth to be deliberated.     

Safe anesthesia for endoscopic laryngeal laser surgery

Anesthesia safety for endoscopic laryngeal laser surgery has been a major limiting factor for laser applications in the larynx and the hypopharynx. Several anesthesia techniques have been proposed and each technique appears to have its own limitations. This paper will deal with the distinct advantages offered by the malleable copper tube which is used for delivery of the open Venturi system anesthesia for endoscopic laser surgery. A retrospective study of 100 patients who have undergone this modality of anesthesia at our institution will be presented. Our conclusion from this study shows clearly the superiority of the copper tube over the conventional aluminium-foil-wrapped endotracheal tube in safety and the exposure of the larynx during surgery.