Occupational Health Risk Assessment of Low Concentrations Benzene Toluene and Xylenes / 中华劳动卫生职业病杂志

Objective@#To Assess occupational health risks of exposuring to low concentrations (lower than occupational exposure limit, OEL) benzene, toluene and Xylenes.@*Methods@#Qualitative evaluation, semi-quantitative evaluation and quantitative evaluation from guidelines for occupational health risk assessment of chemicals in the workplace were conducted to assess occupational health risks exposure to benzene compounds in different workplaces of 5 manufacturing enterprises, respectively.@*Results@#Concentrations of benzene, toluene and Xylenes in all workplaces were lower than OEL. Qualitative evaluation showed that occupational health risk level was 4 exposure to benzene and Xylenes in all workpalces, while 2 exposure to toluene. Semi-quantitative evaluation showed low level (2 of 5) risks in all workplaces exposured to benzene compounds excepted 4 workpalces exposured to benzene, the latter was moderate (3 of 5) . Quantitative evaluation gave unacceptable carcinogenic risk (higher than 10-4) of benzene in the wood toy manufactory, and the highest risk was (1.48~5.26) ×10-4. The occupational health risks of benzene and Xylenes were all unacceptable (HQ>1) in 9 workplaces.@*Conclusion@#There still need more attention to occupational health risks exposure to benzene, toluene and Xylenes lower than OEL.

Preventive and therapeutic mechanism of ginkgo biloba extract on liver injury poisoned by xylene / 天津医药

@#Objective To investigate the potential effect and molecular mechanism of ginkgo biloba extract (GBE) on the expression of inflammatory factors in liver tissue of mice poisoned by xylene. Methods A total of 30 clean grade healthy Kunming mice were randomly divided into normal control group, model group and ginkgo biloba extract intervention group (GBE group). Mice of three groups were granted free access to food and water. The concentration of xylene inhalation was 110-130 mg/m3 (the air samples were collected in the box, and the gas chromatogram was measured by direct injection method) in model group and GBE group. The mice in control group inhaled air. GBE group was intraperitoneally injected with 50 mg/(kg·d) of GBE. Control and model groups were intraperitoneal injected with same amount of normal saline. After 8 weeks, mice were sacrificed, and serum and liver tissues were retained. The serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBIL), alkaline phosphatase (ALP) and glutamyl transpeptidase (GGT) were measured. Haematoxylin and Eosin staining was used to observe pathological changes of liver tissue. RT-PCR and Western blot assay were used to detect the expression levels of nuclear factor kappa B (NF-κB), tumor necrosis factor alpha (TNF-α) mRNA and protein in liver tissue. Results Compared with the control group, the liver tissue was damage seriously in the model group. The blood biochemical indexes (ALT, AST, TBIL, ALP and GGT) were significantly increased (P＜0.05), and the NF-κB, TNF-α mRNA and protein were significantly increased in the model group (P＜0.05). Compared with the model group, the liver tissue damage was reduced, the blood biochemical indexes (ALT, AST, TBIL, ALP and GGT) were significantly decreased (P＜0.05) and the NF-κB, TNF-α mRNA and protein were significantly down-regulated in the GBE group (P＜0.05). Conclusion Ginkgo biloba extract can reduce hepatic inflammatory response of mice poisoned by xylene through inhibiting the expression of NF-κB and TNF-α inflammatory factors.

Intoxicación por amitraz. Un reporte de caso / Amitrazpoisoning: case report

Resumen El amitraz es un compuesto insecticida utilizado a nivel mundial para el control de plagas, en especial en áreas rurales agrícolas y ganaderas. La intoxicación por amitraz es infrecuente en Colombia. Se presenta el caso de una paciente de 18 años de edad, quien ingresa al servicio de urgencias 3 horas después de la ingesta de Triatox® (amitraz) en cantidad desconocida. La mujer llega con depresión del estado de conciencia, dificultad respiratoria, hipotensión, bradicardia, miosis y acidosis metabólica compensada con alcalosis respiratoria, por lo que se le suministra tratamiento inicial con medidas de soporte vital en el servicio de urgencias, con posterior necesidad de traslado y soporte en la unidad de cuidados intensivos, siendo dada de alta de la misma unidad 24 horas después del ingreso. El caso pone en consideración la similitud clínica entre la intoxicación por amitraz y la debida a otros compuestos tóxicos más frecuentes como carbamatos, organofosforados y opioides, los cuales requieren un manejo distinto.

Abstract Amitraz is an insecticide compound used worldwide for controlling pests, especially in agricultural and livestock areas. However, amitraz poisoning in Colombia is rare. This article reports the case of an 18-year-old female patient who was admitted in the emergency service 3 hours after the intake of an unknown amount of Triatox® (amitraz). The patient presented with a depressed level of consciousness, respiratory distress, hypotension, bradycardia, myosis and metabolic acidosis compensated with respiratory alkalosis. Initial treatment was provided using life support measures in the emergency ward, and subsequent transfer and support in the intensive care unit. She was discharged 24 hours after admission. This case considers the clinical similarity between amitraz poisoning and poisoning caused by other more frequent toxic compounds such as carbamates, organophosphates and opioids, which require different management.

Early Liver and Kidney Dysfunction Associated with Occupational Exposure to Sub-Threshold Limit Value Levels of Benzene, Toluene, and Xylenes in Unleaded Petrol

BACKGROUND: Unleaded petrol contains significant amounts of monocyclic aromatic hydrocarbons such as benzene, toluene, and xylenes (BTX). Toxic responses following occupational exposure to unleaded petrol have been evaluated only in limited studies. The main purpose of this study was to ascertain whether (or not) exposure to unleaded petrol, under normal working conditions, is associated with any hepatotoxic or nephrotoxic response. METHODS: This was a cross-sectional study in which 200 employees of Shiraz petrol stations with current exposure to unleaded petrol, as well as 200 unexposed employees, were investigated. Atmospheric concentrations of BTX were measured using standard methods. Additionally, urine and fasting blood samples were taken from individuals for urinalysis and routine biochemical tests of kidney and liver function. RESULTS: The geometric means of airborne concentrations of BTX were found to be 0.8 mg m-3, 1.4 mg m-3, and 2.8 mg m-3, respectively. Additionally, means of direct bilirubin, alanine aminotransferase, aspartate aminotransferase, blood urea and plasma creatinine were significantly higher in exposed individuals than in unexposed employees. Conversely, serum albumin, total protein, and serum concentrations of calcium and sodium were significantly lower in petrol station workers than in their unexposed counterparts. CONCLUSION: The average exposure of petrol station workers to BTX did not exceed the current threshold limit values (TLVs) for these chemicals. However, evidence of subtle, subclinical and prepathologic early liver and kidney dysfunction was evident in exposed individuals.

Ação solvente do salicilato de metila sobre Resilon e guta-percha / Solvent action of methyl salicylate on Resilon and gutta-percha

Objetivo: O objetivo deste estudo foi avaliar a ação do salicilato de metila na dissolução de Resilon e guta-percha. Material e método: Dez discos de Resilon, guta-percha (Alpha) e guta-percha (ProTaper) foram preparados (10 mm de diâmetro × 1 mm de espessura) e mantidos a 37 °C por 48 horas. Cada amostra foi pesada em uma balança de precisão, determinando a massa inicial. Os espécimes foram imersos em salicilato de metila ou xilol (controle) por 5 minutos, lavados em água por 30 minutos, secos e, posteriormente, pesados em intervalos de 24 horas, até a estabilização da massa (massa final). A capacidade solvente foi expressa pela diferença entre a massa final e a inicial. Os dados foram submetidos à análise de variância e teste de Tukey, com nível de significância de 5%. Resultado: Os resultados mostraram que o salicilato de metila foi mais efetivo sobre o Resilon do que sobre a guta-percha (p <0,05). A capacidade solvente do salicilato de metila foi semelhante à do xilol sobre o Resilon (p >0,05). O xilol mostrou melhor atuação sobre a guta-percha em comparação ao salicilato de metila (p < 0,05). Conclusão: Concluiu-se que o salicilato de metila não apresenta atuação solvente sobre guta-percha, sendo eficaz na dissolução do Resilon. O salicilato de metila demonstra ser alternativa ao uso do xilol durante o retratamento endodôntico de dentes obturados com Resilon.

Objective: The aim of this study was to evaluate the action of methyl salicylate in dissolving Resilon and gutta-percha. Material and method: Ten discs of Resilon, Alpha gutta-percha and ProTaper gutta-percha were prepared (10 mm diameter × 1 mm thick) and kept at 37 °C for 48 hours. Each sample was weighed in a balance of accuracy determining the initial mass. The specimens were immersed in methyl salicylate or xylene (control) for 5  minutes, rinsed in water for 30 minutes, dried and subsequently weighed in 24 hours intervals until the stabilization of weight (final mass). The solvent capacity was expressed by the difference between the final and initial mass. The data were analyzed by using ANOVA and Tukey test with significance level of 5%. Result: The results showed that the methyl salicylate was more effective on Resilon than on gutta-percha (p < 0.05). Methyl salicylate and xylene had similar solvent action on Resilon (p > 0.05). The xylene showed better performance on gutta-percha than methyl salicylate (p < 0.05). Conclusion: It was concluded that methyl salicylate did not show solvent action on gutta-percha, however it showed effectiveness in dissolution of Resilon. Thus methyl salicylate can be a possible alternative to the use of xylene during endodontic retreatment of teeth obturated with Resilon.

Study of the Current Status and Influence Factors of Indoor Air Pollution through 138 Houses in Urban Area in Xi’an / 环境与健康杂志

Objective To get knowledge of the indoor air pollution states in the newly renovated apartments in Xi’an city, and explore the relationship among the major pollutants and the relationship between the pollutants and the differences of seasons. Methods From January, 2006 to May, 2007, we randomly selected 138 newly renovated (3 months or less) apartments in the urban area of Xi’an city, tested their indoor (including bedrooms, living room, dining room, kitchen, bathrooms, study, a total of 597) content of formaldehyde, total volatile organic compounds (TVOCs), ammonia, benzene, toluene and xylene. Results Among which were detected in all of the pollutants, total volatile organic compounds (TVOCs) and formaldehyde own the highest exceeding rates, respectively 69.8% and 60.8%. They are followed by ammonia, whose exceeding rate is 13.2%, xylene which has the highest exceeding rate among the benzene compounds, 8.7%. We did comparative analysis of the concentration in different types of rooms for the pollutants which are among the top four in exceeding rate ranks, and found that only for formaldehyde, there is significant difference in statistics (P