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.     

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.     

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。     

Tibialis posterior dysfunction as a cause of flatfeet in elderly patients

Background: Tibialis posterior is a frequent cause of an acquired flatfoot deformity and the prevalence is not known. If tibialis posterior dysfunction was found to occur frequently, a greater awareness may result leading to earlier patient diagnosis, referral and treatment.Objectives: To validate a screening questionnaire for tibialis posterior dysfunction, and to investigate the prevalence of tibialis posterior dysfunction in a high-risk patient population.Methods: The screening questionnaire was given prospectively to 65 patients (44 females, 21 males; mean age 79.6 years) attending an unrelated care of the elderly appointment. A foot and ankle surgery fellow separately examined all feet for tibialis posterior dysfunction.Results: The survey was 100% sensitive and 98.3 % specific at detecting tibialis posterior dysfunction. Six of the 65 patients (5 females, 1 male) had tibialis posterior dysfunction, and two had bilateral involvement. All six of the patients had longstanding symptoms, all had consulted their doctor and three had seen an orthopaedic surgeon; only one of the six patients had been correctly diagnosed.Conclusions: This study suggests that tibialis posterior dysfunction occurs frequently, but is seldom diagnosed in elderly women. Further epidemiologic studies are needed to determine the true prevalence.     

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.     

Trapeziometacarpal joint osteoarthritis: a retrospective study comparing arthrodesis to tendon interposition arthroplasty

Abstract Surgical management of trapeziometacarpal joint osteoarthritis (OA) is still controversial. The aim of this study was to evaluate and compare results of trapeziometacarpal arthrodesis and of tendon interposition arthroplasty. One hundred twenty-six patients suffering from trapeziometacarpal OA underwent surgery between 1996 and 2001. Of these patients, 62 (78 thumbs) treated with joint arthrodesis and 33 (41 thumbs) treated with tendon interposition arthroplasty with abductor pollicis longus (APL) have been evaluated at follow-up and therefore entered this study. Mean age was 53 years, while the mean follow-up was 36 months. Overall results were satisfactory in 84 patients with good pain improvement. Patients treated with arthrodesis showed better functional ability in bi-digital pinch and grip strength. First finger opposition motion, however, was better conserved in patients treated with interposition arthroplasty. Fusions had an 11.5% complication rate (9 thumbs) with nonunions, whereas 14.8% (6 thumbs) of patients treated with interposition arthroplasty developed 1 first metacarpal base collapse, resulting in 1 first ray length reduction. Despite complications, however, patients did not report unsatisfactory results and generally experienced marked pain reduction. This study shows that arthrodesis can be considered the treatment of choice in patients suffering from trapeziometacarpal OA at Eaton stage III or less, whatever the age and when a good pinch strength is needed.