Effects of smoking and drinking on excretion of hippuric acid among toluene-exposed workers

Summary In order to investigate possible effects of smoking and drinking on the metabolism of toluence in occupational settings, 206 toluene-exposed men (mean age: 31.4 years) in shoemaking, painting, or surface-coating workshops together with 246 nonexposed control men (36.8 years) were studied for the time-weighted average intensities of exposure to toluene, hippuric acid concentration in shift-end urine samples, and the two social habits of smoking and drinking. The mean daily consumptions of cigarettes and ethanol were about 20 pieces and 10 g among smokers and drinkers, respectively. The geometric mean toluene concentration among the exposed subjects was about 20 ppm, with a maximum of 521 ppm. Regression analysis after classification of the subjects by smoking and drinking clearly demonstrated that the two social habits, when combined, markedly reduce the hippuric acid level in the urine of workers exposed to was a significant association between smoking and drinking habits, which hindered separate evaluation of the effects of the two habits on toluene metabolism. Comparison of the present results with the findings reported in the literature, however, suggested that the observed effects may be attributable to smoking rather than to drinking habits.     

Biochemical characterisation of para-aminophenol-induced nephrotoxic lesions in the F344 rat

The acute biochemical effects of the nephrotoxin p-aminophenol (PAP) were studied in detail using a combination of conventional bioanalytical and ¹H-NMR spectroscopic methods. Dosing PAP (25–100 mg/kg) to male F344 rats resulted in a dose-related proximal nephropathy with consequent elevations in urinary enzymes, glucose, and urine total protein as shown by conventional methodology. ¹H-NMR spectroscopy at 400 MHz of urine from PAP-treated rats also revealed a characteristic glycosuria, with concomitant amino aciduria. The increased excretion of these compounds indicates functional defects in the proximal tubule and reduced solute reabsorption efficiency. In addition, ¹H-NMR urinalysis and conventional enzymatic analysis showed a dose-related lactic aciduria. Other changes detected by ¹H-NMR included a dose-related reduction in the excretion of citrate (confirmed by a conventional biochemical method) and an increase in the excretion of acetate. The degree of abnormalities shown by ¹H-NMR urinalysis agreed well with histopathological observations and conventional biochemical indices of nephrotoxicity. ¹H-NMR urinalysis therefore serves to highlight changes in the excretion of low MW urine components not routinely studied by conventional biochemical analysis.Abbreviations ALP alkaline phosphatase - APAP paracetamol - BUN blood urea nitrogen - GFR glomerular filtration rate - GOT glutamate oxaloacetate transaminase - LAP leucine aminopeptidase - LDH lactate dehydrogenase - MW molecular weight - NAG N-acetyl--D-glucosaminidase - PAP p-aminophenol - ppm parts per million - TMAO trimethylamine N-oxide - UFR urine flow rate     

n-Hexane urine elimination and weighted exposure concentration

Summary The concentration of n-hexane in urine was determined in 30 subjects occupationally exposed to n-hexane (median value 59.6 mg/m³) in a shoe factory. The measurement of the substance was performed by means of a Hewlett-Packard 5880 gas chromatograph supplied with a Hewlett-Packard 5970 Mass Selective Detector. The analyses were performed by the head space method (constant volume method, after determination of the urine partition coefficient by the multiple phase equilibration method). The authors found a significant correlation between the n-hexane urine concentrations (g/1, Cu) and the n-hexane environmental concentrations (mg/m³, Ci) (r = 0.84; Cu = 0.0669 x Ci + 0.8396).This work was supported by the research funds given to Fondazione Clinica del Lavoro, Pavia by the Health Council     

On the need of a sampling strategy in biological monitoring: The example of hexane exposure

Ambient and biological monitoring of hexane exposure were repeatedly carried out in 14 female shoe makers. Airborne hexane (Ci-H) was measured in 4-h samples collected by a diffusive method. Urinary spot samples were collected before, during (at noon), and at the end of a work shift. 2,5-Hexanedione (2,5HD) in urine collected at noon was poorly related to morning Ci-H. End-of-shift 2,5HD were also poorly related to afternoon air samples. The correlation was still relatively low when end-of-shift 2,5HD was related to 8-h TWA Ci-H (r= 0.44; P<0.01 on=" a=" linear=" scale,=" and=">r-0.58, P< 0.01=" on=" a=" log-log=" scale).=" end-of-shift=" 2,5hd=" levels=" estimated=" on=" the=" basis=" of=" pre-shift=" values=" using=" a=" mathematical=" model=" were=" much=" higher=" (2.3=" times=" on=" average)=" than=" those=" experimentally=" measured=" during=" the=" study=" period.=" owing=" to=" its=" relatively=" long=" half-time,=" 2,5hd=" seems=" to=" be=" influenced=" not=" only=" by=" current=" exposure,=" but=" also=" by=" hexane=" absorbed=" during=" the=" day(s)=" preceding=" sampling.=" the=" lack=" of=" a=" sampling=" strategy=" may=" account=" not=" only=" for=" inconsistencies=" between=" environmental=" and=" biological=" data,=" but=" also=" for=" a=" possible=" misuse=" of=" biological=" monitoring=" when=" utilized=" for=" risk=" assessment.=" despite=" sometimes=" poor=" correlations=" with=" ci-h,=" 2,5hd=" may=" still=" be=" preferred=" to=" other=" indicators=" as=" a=" marker=" of=" effective=" internal=" dose.=" a=" sampling=" strategy=" should=" ensure=" that=" measured=" values=" are=" representative=" of=" the=" individual=" risk=" for=" adverse=">     

Attentional Difficulties and the Effectiveness of a Visual Representation Strategy for Counseling Drug-Addicted Clients

Three hundred thirty-one opioid-addicted clients in methadone treatment were randomly assigned to counselors who used either mappingenhanced or standard counseling. Those counseled with mapping had lower percentages of during-treatment urine specimens that were positive for either cocaine or opiates, and they were rated by their counselors as having higher rapport, motivation, and self-confidence. Clients were further classified into those exhibiting either good or poor attention during an intake interview. The results suggest that clients with poor attention are more likely to have positive urines, but that this tendency appears to be reduced under mapping-enhanced counseling.     

AVE-763B型自动尿沉渣分析仪检测红细胞影响因素的分析

目的：分析用AVE-763B型自动尿沉渣分析仪检测红细胞的影响因素。方法：采用AVE-763B型自动尿沉渣分析仪和显微镜检测法分析了545份住院患者的尿液标本,并将二者结果进行比较。结果：AVE-763型尿沉渣全自动检测仪检测标本红细胞的假阳性率为15.2%,假阴性率为0,灵敏度为100%,特异度为84.8%。与显微镜检测法相比,差异有统计学意义（P〈0.05）。结晶、上皮细胞核、酵母菌等是影响AVE-763B型自动尿沉渣分析仪检测结果的主要因素。结论：为获得准确可靠的尿红细胞检测结果,应以AVE-763B型自动尿沉渣分析仪进行筛查并结合显微镜检查。     

尿白蛋白准确定量有待解决的课题

尿中自蛋白定量是很重要的常规检验项目.尤其是近年来兴起的"尿微量白蛋白"定量在早期发现与监测肾损伤方面起着重要的作用.但最近国际权威组织认为尿白蛋白定量这一看似普通而简单的试验却仍存在许多问题.本文就一些国家发布的指南中的多处不一致,定量中存在的不少难以解决的问题,以及国际组织提出的多项改进建议和需深入研究的课题加以介绍并提出看法,包括在国内停止使用"尿微量白蛋白"一词,而仍用"尿白蛋白"定量.     

葡萄糖对尿液白细胞干化学法测定影响的探讨

目的分析葡萄糖(Glu)对尿液白细胞(WBC)干化学酯酶法(简称干化学法)测定的影响,以提高检测准确率。方法对584例WBC镜检阳性的临床尿液检测资料回顾分析其Glu和WBC干化学结果;选取只有WBC干化学结果分别为±、+、++、+++阳性的新鲜尿液各5份,每份2管(每管10 mL),分为Glu加入组和H2O2加入组,分别对每组样本加入不同浓度Glu和H2O2,并进行干化学测定。在Glu加入组每次测定的同时,用去除Glu模块的试条进行重复测定。结果584例尿检结果中,Glu+++组与Glu++++组的WBC干化学假阴性率均高于Glu阴性组(P=0.001,P=0.000)。WBC干化学阳性检出数随尿Glu浓度的升高而减少[优势比(OR)=0.100,P=0.000],但不受H2O2的影响。结论尿Glu浓度为83.33 mmol/L(15 g/L)时,尿WBC干化学测定已明显受干扰,其受干扰程度随尿Glu浓度的升高而增大,是Glu干扰了尿WBC干化学测定,而非Glu模块的反应产物H2O2。     

肾脏超声及血尿常规在肾病综合征出血热早期诊断中的价值

目的探讨肾综合征出血热患者在发热期肾脏超声及血尿常规的变化特点。方法检测62例发热期肾综合征出血热患者肾脏超声及血、尿常规。结果 62例患者中白细胞计数升高为77.42%,其中中性粒细胞百分比升高占74.19%,淋巴细胞计数降低者占53.23%,血小板计数低于正常98.39%;62例患者组中98.39%的患者尿蛋白阳性,与正常组比较,尿蛋白阳性的发生率有非常显著性差异P<0.01;62例患者中有54例不同程度的肾脏超声示双肾肿大,阳性率达87.09%,双肾各径平均大于对照组,有显著性差异<0.05。结论肾脏超声检查及血、尿常规检测对肾综合征出血热患者早期的疾病诊断有重要参考价值。     

镍铬合金烤瓷修复体拆除前后患者尿和血清中镍铬含量的评估

目的 通过测定镍铬合金烤瓷修复体拆除前后患者尿和血清中的镍铬含量,对镍铬合金的临床应用安全性进行科学评估.方法 选择因怀疑镍铬合金烤瓷修复体的镍、铬元素对全身有影响,主动要求拆除修复体的患者86例,于修复体拆前、拆后1个月采用石墨炉原子吸收光谱法检测患者尿镍、铬含量(86例)和血清镍、铬含量(69例).结果 镍铬烤瓷修复体拆除前后86例患者尿镍含量分别为(3.52±3.05)和(3.31 ±3.28) μg/L,尿铬含量分别为(0.81±0.54)和(1.34±1.15) μg/L;修复体拆除前后69例患者血清镍含量分别为(2.04±1.06)和(2.67±2.32) μg/L,血清铬含量分别为(1.07±0.88)和(1.02±0.86) μg/L;拆除前后差异均无统计学意义(P＞0.05).结论 本项研究条件下镍铬合会烤瓷修复体释放的镍、铬离子量微小,不足以对人体尿液及血液中的镍、铬含量造成影响.