Effects of Toluene on the Development of the Inner Ear and Lateral Line Sensory System of Zebrafish / 生物医学与环境科学（英文）

Objective@#The aim of this study was to explore the ototoxicity of toluene in the early development of zebrafish embryos/larvae.@*Methods@#Zebrafish were utilized to explore the ototoxicity of toluene. Locomotion analysis, immunofluorescence, and qPCR were used to understand the phenotypes and molecular mechanisms of toluene ototoxicity.@*Results@#The results demonstrated that at 2 mmol/L, toluene induced zebrafish larvae death at 120 hours post fertilization (hpf) at a rate of 25.79% and inhibited the rate of hatching at 72 hpf. Furthermore, toluene exposure inhibited the distance travelled and average swimming velocity of zebrafish larvae while increasing the frequency of movements. As shown by fluorescence staining of hair cells, toluene inhibited the formation of lateral line neuromasts and middle line 1 (Ml @*Conclusion@#This study indicated that toluene may affect the development of both the inner ear and lateral line systems in zebrafish, while the lateral line system may be more sensitive to toluene than the inner ear.

Avaliação da exposição a BTEX em postos de revenda de combustíveis no Rio de Janeiro, Brasil, e os riscos à saúde do trabalhador / Assessment of exposure to BTEX in vehicle filling stations in Rio de Janeiro, Brazil, and risks to workers' health / Evaluación de la exposición a BTEX en puestos de reventa de combustibles, en Río de Janeiro, Brasil, y riesgos para la salud del trabajador

A gasolina é uma mistura complexa de substâncias, dentre elas estão hidrocarbonetos como o benzeno, tolueno, etilbenzeno e xilenos (BTEX), sendo esses compostos emitidos para a atmosfera, com destaque ao benzeno, por ser comprovadamente carcinogênico. Objetivamos avaliar as concentrações de BTEX no ar de postos de revenda de combustíveis no Município do Rio de Janeiro, Brasil, e calcular o risco de câncer associado a estas exposições. Foram realizados dois tipos de amostragem (fixa e móvel) adaptadas da metodologia nº 1.501 do Instituto Nacional de Segurança e Saúde Ocupacional (Estados Unidos), em seis postos de revenda de combustíveis na Zona Oeste da cidade. A amostragem fixa foi feita próxima às bombas de combustível, enquanto a móvel foi realizada através da coleta do ar na zona respiratória dos trabalhadores (frentistas), conforme estes se deslocavam pelo posto. As amostras foram analisadas por cromatografia gasosa com detecção por ionização em chama. Com os resultados das amostragens foram feitos os cálculos de risco à saúde, usando os indicadores Quociente de perigo (HQ) e Risco de câncer (CR), para avaliar os possíveis efeitos não-carcinogênicos e carcinogênicos, respectivamente, nos trabalhadores dos postos de revenda de combustíveis. As concentrações ambientais para a maioria dos compostos BTEX foram abaixo dos limites preconizados, menos para o benzeno, um composto carcinogênico, que apresentou concentrações muito acima dos limites, levando a altos valores de risco de câncer. Os resultados demonstraram que há riscos à saúde dos trabalhadores de postos de revenda de combustíveis, principalmente o risco de desenvolver câncer, devido à exposição excessiva ao benzeno.

Gasoline is a complex mixture of substances, including aromatic hydrocarbons such as benzene, toluene, ethylbenzene, and xylenes (BTEX). These compounds are emitted into the air, with the special relevance of benzene since it is provenly carcinogenic. The study aimed to assess BTEX concentrations in filling stations in the city of Rio de Janeiro, Brazil, and to calculate the cancer risk associated with such exposures. Two types of sampling were performed (stationary and mobile), adapted from methodology n. 1,501 (U.S. National Institute for Occupational Safety and Health) for aromatic hydrocarbons, in six filling stations in the West Zone of Rio de Janeiro. Stationary sampling was done near the fuel pumps, while mobile sampling was done in the breathing zone of the workers (station attendants) as they moved around the station. The samples were analyzed with gas chromatography flame ionization detector. The sampling results were used to calculate the health risk, using the indicators Hazard quotient (HQ) and Cancer risk (CR) to assess the possible non-carcinogenic and carcinogenic effects, respectively, in filling station workers. Environmental concentrations for the most of the BTEX compounds were below the recommended limits, except for benzene, a carcinogenic compound, which displayed concentrations far above the limits, leading to high cancer risk values. The results showed that there are health risks for filling station attendants, especially the risk of developing cancer from excessive exposure to benzene.

La gasolina es una mezcla compleja de sustancias, entre ellas existen hidrocarburos como el benceno, tolueno, etilbenceno y xilenos (BTEX), emitiéndose estos compuestos a la atmósfera, donde se destaca el benceno, al tratarse de un carcinogénico comprobado. Los objetivos fueron evaluar las concentraciones de BTEX en el aire de puestos de reventa de combustibles, en el municipio de Río de Janeiro, Brasil, así como calcular el riesgo de cáncer asociado a estas exposiciones. Se realizaron dos tipos de muestra (fija y movible), adaptadas de la metodología nº 1.501 del Instituto Nacional de Seguridad y Salud Laboral (EE.UU.), en seis puestos de reventa de combustibles de la zona oeste de la ciudad. La muestra fija se realizó cerca de las bombas de combustible, mientras que la móvil se hizo mediante tomas de aire en la zona respiratoria de los trabajadores (de la gasolinera), a medida que estos se desplazaban por el lugar de trabajo. Las muestras se analizaron por cromatografía gaseosa con detección por ionización en llama. Junto a los resultados de las muestras, se realizaron cálculos de riesgo para la salud, usando los indicadores Cociente de peligro (HQ) y Riesgo de cáncer (CR), con el fin de evaluar los posibles efectos no-carcinogénicos y carcinogénicos, respectivamente, en los trabajadores de los puestos de reventa de combustibles. Las concentraciones ambientales para la mayoría de los compuestos BTEX estuvieron por debajo de los limites preconizados, menos en el caso del benceno, un compuesto carcinogénico, que presentó concentraciones muy por encima de los límites, llevando a altos valores de riesgo de cáncer. Los resultados demostraron que existen riesgos para la salud de los trabajadores de puestos de reventa de combustibles, principalmente, riesgo de desarrollar cáncer, debido a la exposición excesiva al benceno.

Neuropsychological effects among workers exposed to organic solvents / Efectos neuropsicológicos en trabajadores expuestos a disolventes orgánicos

Abstract: Objective: To assess neuropsychological performance among workers at a paint factory in Mexico City. Materials and methods: During 2004 and 2005 we assessed the neuropsychological performance of 208 workers who were exposed to organic solvents at a paint factory, mainly toluene and xylene. We categorized workers into low and high exposure groups using a cumulative index for toluene, based on times spent in different tasks. We evaluated cognitive and motor functions with 13 neuropsychological tests. Results: We found lower attention, longer time to complete the test β=5.5 (R2=12.3%), and a lower score in the motor-cognitive test β=-15.7 (R2=19.5%) in the high exposure group through multiple linear regression model analysis, with adjustment for age and education. Conclusion: Our results are similar to the ones reported in the literature, but the effects are less severe, probably due to lower exposure to organic solvents.

Resumen: Objetivo: Evaluar el desempeño neuropsicológico de los trabajadores de una fábrica de pintura en la Ciudad de México. Material y métodos: Se evaluó el desempeño neuropsicológico de 208 trabajadores expuestos a disolventes orgánicos, principalmente tolueno y xileno, en una fábrica de pintura en la Ciudad de México durante 2004 y 2005. Se categorizaron en grupos de baja y alta exposición con un índice acumulado de tolueno con base en el tiempo empleado por actividad. Se evaluaron funciones motoras y cognitivas con 13 pruebas neuropsicológicas. Resultados: Se registró un tiempo más largo para completar la prueba β=5.5 (R2=12.3%) y una puntuación baja en la prueba motor-cognitiva de β=-15.7 (R2=19.5%) en el grupo de alta exposición en los modelos de regresión lineal múltiple, ajustados por confusores. Conclusión: Los presentes resultados son similares a los reportados en la literatura, aunque los efectos son menos graves, probablemente debido a la baja exposición.

Performance catalytic ozonation over the carbosieve in the removal of toluene from waste air stream

Toluene is a volatile organic compound, one of 189 hazardous air pollutants [HAP[s]] and the most important pollutant found in most industries and indoor environments; owing to its adverse health, toluene must be treated before being released into the environment. In this research study, a continuous-flow system [including an air compressor, silica gel filters and activated charcoal, impinger, an ozone generation and a fixed bed reactor packed with the carbosieve in size 1.8-2.3 mm, specific surface: 972 m[2]/g,] was used. This glass reactor was 0.7 m in height; at a distance of 0.2 m from its bottom, a mesh plane was installed so as to hold the adsorbent. Moreover, 3 l/min oxygen passed through this system, 0.43 g/h ozone was prepared. The flow rate of waste airstream was 300 ml/min. The efficiency of this system for removal of toluene was compared under the same experimental conditions. Under similar conditions, performance of catalytic ozonation was better in toluene removal than that of ozonation and carbosieve alone. On average, increasing the removal efficiency was 45% at all concentrations. When carbosieve and ozone come together, their synergistic effects increased on toluene degradation. Catalytic ozonation is a suitable, high-efficient and available method for removing toluene from various concentrations of waste air stream. This process due to the short contact time, low energy consuming and making use of cheap catalysts can be used as a novel process for removing various concentrations of volatile organic compounds

Alteraciones hematológicas en trabajadores expuestos ocupacionalmente a mezcla de benceno- tolueno-xileno (BTX) en una fábrica de pinturas / Blood disorders among workers exposed to a mixture of benzene-toluene-xylene (BTX) in a paint factory

Objetivos. Evaluar las tres series celulares sanguíneas e identificar la presencia de hipocromía, macrocitosis, leucopenia, linfocitopenia y trombocitopenia en un grupo de trabajadores expuestos a la mezcla de benceno-tolueno-xileno (BTX). Materiales y métodos. Estudio transversal donde se incluyó a 97 trabajadores de una empresa de pinturas de México a los que se les realizó una biometría hemática convencional y les fue estimada la exposición a través de la dosis diaria potencial acumulada para vapores de BTX. Resultados. Del total de trabajadores, 19,6%, mostró macrocitosis, 18,6%, linfocitopenia, 10,3% hipocromía, 7,2% trombocitopenia y 5,2% leucopenia. La asociación cruda de macrocitosis con exposición a dosis alta de mezcla de BTX fue la única significativa (OR:3,6; IC95%: 1,08 - 13,9; p=0,02) y en la que se estructuró un modelo de regresión logística (OR:6,7; IC95%: 1,33 - 13,55; p:0,02) ajustada por edad, consumo de alcohol y tabaquismo. Conclusiones. Todos los componentes citohemáticos analizados mostraron cambios leves; que podrían estar asociados con la exposición a la mezcla de BTX. De ellos, la macrocitosis podría constituirse en una manifestación precoz que merece ser vigilada.

Objectives. Evaluate the three blood cell series and identify the presence of hypochromia, macrocytosis, leucopenia, lymphopenia, and thrombocytopenia in a group of workers exposed to the mixture of benzene-toluene-xylene (BTX). Materials and methods. A cross-sectional study which included 97 workers from a paint factory in Mexico. The participants underwent conventional blood count and tests for potential cumulative daily dose of BTX fumes, to estimate exposure. Results. From the total of workers, 19.6% showed macrocytosis, 18.6%, lymphopenia, hypochromia 10.3%, 7.2% and 5.2% thrombocytopenia leukopenia. The crude association of macrocytosis with exposure to high doses of BTX mixture was the only with statistical significance (OR: 3.6, 95% CI 1.08 to 13.9, P = 0.02), and the base for a logistic regression model (OR: 6.7, 95% CI 1.33 to 13.55, P = 0.02) adjusted for age, alcohol consumption, and smoking. Conclusions. All blood cytological components analyzed demonstrated mild changes, potentially associated with exposure to the mixture of BTX. Macrocytosis could constitute an early manifestation worthy for surveillance.

Evaluation of the hepatotoxic effects of polyethylene and butylated hydroxy toluene in adult male albino rats

Plastic is used in contact with nearly all packaged foods; plastic is made by combining many toxic synthetic man-made chemicals by a process called polymerization. FDA Office of Food Additive Safety assuming that all plastics migrate toxins into the food they contact. Butylated hydroxy toluene [BHT] is one of additives in LOPE [low-density polyethylene] and HOPE [high-density polyethylene]. Migration into water and food substances have been measured for this BHT antioxidant, generally at higher temperatures than experienced in normal use, there is considerable loss of antioxidants especially with fatty or oily foods so, study for biochemical and histopathological changes induced by Polyethylene and BHT on the liver of adult male albino rats using light and electron microscopes has done as following: Fifty albino rats were divided into five groups. 1[st] group rats served as control, 2[nd] group was gavaged daily with 0.5 ml of com oil [vehicle], 3rd group was administered with polyethylene pellets mixed to food by 1:20 daily, 4[th] group was gavaged with BHT by 1120 of LOSO equal 400 mg/kg/day in com oil, and the 5[th] group was gavaged by combination of polyethylene and BHT at same doses as 3[rd] and 4[th] groups. At the end of experiment which lasts for 12 weeks, all rats were anaesthetized and blood samples were collected for analysis of Alpha Feto Protein CAFP] serum level and liver function tests. Animals were sacrificed, specimens from liver were taken, and prepared for histopathological examination through light and electron microscopes. The study revealed that: There was significant increase of Alanine transaminase [ALT] and Aspartate transaminase CAST] with lowering in alkaline phosphatase level among Polyethylene, BHT and combination of BHT with Polyethylene administered groups compared to control group while AFP level showed significant elevation in both BHT and combined [polyethylene and BHT] group compared to control and polyethylene groups. These biochemical changes had been proved by histopathological examination, liver cells showed cellular infiltration around central vein with dilation and congestion of the vein and blood sinusoids, lobular necrosis with fatty infiltration. Ultrustructurally, liver cells showed muddy cytoplasm contained electro lucent vacuoles, electron dense mitochondria with loss of or few microvilli in bile canaliculi and sinusoids. This study concluded that, BHT gave the most significant toxic effect on liver of albino rats than ingestion of pure polyethylene while toxic effect was more prominent by using combination of both agents

Effects of the Exposure to Polycyclic Aromatic Hydrocarbons or Toluene on Thiobarbituric Acid Reactive Substance Level in Elementary School Children and the Elderly in a Rural Area / 예방의학회지

OBJECTIVES: Polycyclic aromatic hydrocarbons (PAH) and toluene have been reported to induce reactive oxygen species and oxidative stress. This study was performed to investigate the effects of low level exposure to PAHs or toluene on the lipid peroxidation level in elementary school children and the elderly in a rural area. METHODS: Forty seven elementary school children and 40 elderly people who were living in a rural area and not occupationally exposed to PAH or toluene were the subjects of this study. Information about active or passive smoking and diet was obtained using a self-administered questionnaire. The urinary 1-hydroxypyrene (1-OHP), 2-naphthol, hippuric acid and thiobarbituric acid reactive substance (TBARS) concentrations were measured, and these values were corrected with the urinary creatinine concentration. RESULTS: In school children, the geometric means of the urinary 1-OHP, 2-naphthol, hippuric acid and TBARS levels were 0.02 ymol/mol creatinine, 0.47 micron mol/mol creatinine, 0.14 g/g creatinine and 0.95 micron mol/g creatinine, respectively. Those values for the elderly were 0.07 micron mol/mol creatinine, 1.87 micron mol/mol creatinine, 0.11 g/g creatinine and 1.18 micron mol/g creatinine, respectively. The mean levels of urinary 1-OHP, 2-naphthol and TBARS were significantly higher in the elderly subjects than in the children. The urinary TBARS level was not correlated with the urinary 1-OHP, 2-naphthol and hippuric acid, but they were correlated with the age of the subjects. CONCLSIONS: These results suggest that low level inhalation exposure to PAH or toluene does not markedly increase lipid peroxidation, and age is a significant determinant of lipid peroxidation.

relation between the duration of inhalation abuse of a volatile substance and its effect on the testis. a histological and biochemical study in adult male albino rats

Volatile substance abuse in general, and toluene inhalation in particular, for their neuropsychological effects, represents a significant problem in many developed and developing countries. The present work was designed to investigate the histopathological changes in the testis of adult male albino rats, induced by toluene vapour inhalation over different periods. The present study was carried out on forty adult male albino rats with body weights ranging from 60-100g. The animals were categorized into two groups: Group I: [Control Group] included ten rats received no treatment, Group II: [Toluene inhalants] included thirty adult rats exposed to toluene vapour inhalation. A clean dry piece of cotton was soaked with toluene liquid and placed in the covered cages three times daily, each for about thirty minutes for six days per week. These animals were subdivided into three equal subgroups according to the exposure period; Subgroup [A]: ten rats exposed to toluene vapour for two weeks, Subgroup [B]: ten rats exposed to toluene vapour for eight weeks, Subgroup [C]: ten rats exposed to toluene vapour for twelve weeks. At the end of each duration of the experiment, animals were scarificed by decapitation using light ether anesthesia after taking blood samples. I- Histological examination: Specimens were taken from the testis of all rats and processed for examination by light microscope using haematoxylin and eosin stain and ultrastructural study using the transmission electron microscope. II. Hormonal assay: The concentration of testosterone level, luteinizing hormone [LH] and follicle - stimulating hormone [FSH] were estimated by radio immunoassay. III. GAS chromatography: Concentration of toluene vapour in the blood was measured by High performance liquid chromatography. IV. Statistical analysis: The one way ANOVA test was applied to estimate the significant values of the hormonal assay for serum testosterone, LH and FSH and the 5% level of significance was chosen. The histopathological changes observed in the testis of rats exposed to toluene inhalation demonstrated its potentials to induce cytotoxic effects on the spermatogenic cells, Sertoli cells and the interstitial cells of Leydig. The severity of the toluene damaging potentials appeared to be dependent on and directly proportionate to the duration of toluene inhalation. So, the histological changes were mild and scattered in the testis specimens of group A [2 weeks inhalation] and was more severe in both eight and twelve weeks groups. The correlation between high performance liquid chromatography for toluene gas in blood, the biochemical gonadal and gonadotrophin hormonal assay and the histological assessment, explored the various mechanisms that were incorporated in the establishment of the toluene induced testicular injury. The present study proved the undoubting evidences for the damage potentials of toluene on the testis as the major reproductive organ in the male. Furthermore, the study showed the direct proportionality between the toxic effects of toluene vapor and the length of the exposure duration. Yet, the observed histological alterations were highly suggestive for a probable impaired reproduction in experimental animals which needs further study

Criterios para la vigilancia biológica en la exposición laboral al tolueno / Criteria for surveillance of work-related exposure to toluene

Se detectaron en los exámenes periódicos del personal con riesgo de exposición a tolueno, valores alterados en su estudio específico de control biológico (ácido hipúrico en orina), sin correlato clínico. El objetivo de este estudio fue revisar los datos disponibles relacionados con la seguridad y eficacia del rastreo de ácido hipúrico en orina como control y determinar el estado actual de la población en estudio, respecto de si se encuentra o no expuesta al tolueno, mediante rastreos que testifiquen datos más confiables. Se partió de la hipótesis de que el ácido hipúrico en orina es un examen de baja especificidad e influenciado por múltiples factores confundidores, lo cual implica una tasa de falsos positivos alta. Para aumentar la especificidad, se agregó otro test de control de exposición al tolueno consistente en la determinación de ortocresol en orina. Posteriormente se compararon los niveles de ácido hipúrico y ortocresol en 35 trabajadores expuestos y 5 no expuestos. En los primeros, 12 (12/35) presentaron ácido hipúrico sobre la norma, en tanto los segundos mostraron uno (1/5) alterado. El ortocresol resultó normal en todos los sujetos estudiados. Los niveles de exposición estuvieron bajo la norma en todos ellos. El estudio confirmaría la baja especificidad del ácido hipúrico como control de exposición, lo que implica una tasa alta de falsos positivos. El análisis de ortocresol es, en principio, más preciso y exacto. Aunque desconocemos la especificidad del mismo medida en poblaciones de tamaño suficiente, sería más sensible para detectar expuestos. La suma de ambos aumentaría la especificidad total y disminuiría la tasa de falsos positivos. Se propone, en consecuencia, un nuevo programa de vigilancia biológica.

Trabalho em convés de navios químicos: um estudo sobre os riscos à saúde / Work in deck of chemical ships

Pouco estudado na literatura mundial e sem referências brasileiras disponíveis, o trabalho em convés de navios químicos representa um risco de exposiçäo à carga, risco este que varia de acordo com: a) natureza da carga, b) grau de automatizaçäo de navios e c) procedimentos utilizados na realizaçäo das tarefas. Descreve as operaçöes de três navios tanques que transportam produtos químicos numa rota que se inicia no Brasil, compreende Argentina, Caribe, Estados Unidos e termina o ciclo no Brasil. Apresenta dados da caracterizaçäo de um grupo amostral de 44 marítimos, quanto à distribuiçäo etária, hábitos de vida, história ocupacional, doenças pregressas e atuais, e queixas no momento do estudo. Em relaçäo à exposiçäo à carga, foram definidos três grupos homogêneos de exposiçäo: a) um grupo regularmente exposto, formado por contramestres, bombeadores, marinheiros e moços de convés; b) um grupo ocasionalmente exposto, formado por oficiais de naútica e imediatos; c) um grupo näo exposto, formado pelos oficiais de radiocomunicaçöes e pela tripulaçäo de câmara, composta de taifeiros e cozinheiros. Foram também realizadas, durante o trapeamento de tanques com tolueno, mediçöes das concentraçöes de tolueno ambiental e de ácido hipúrico urinário, no grupo que entrou no tanque para a atividade, e no restante da tripulaçäo de convés e câmara. Alguns fatores contribuíram para dificultar a definiçäo do risco químico do grupo estudado: a) a grande diversidade de tarefas e de produtos transportados e manuseados; b) os diferentes cenários de exposiçäo; c) a sazonalidade da exposiçäo; d) a variaçäo de comportamento de risco durante os períodos de embarque e em terra, nao foi possível quantificar o risco químico do grupo estudado. Ainda do ponto de vista epidemiológico, o tamanho dos grupos é um fator limitante pra a correlaçäo entre as queixas e os achados clínicos encontrados, e as atividades profissionais. As observaçöes realizadas possibilitam algumas correlaçöes e servem como base para a definiçäo de uma estratégia para estudos epidemiológicos mais complexos, e para a determinaçäo do risco toxicológico das funçöes de convés nos navios químicos.

Biological monitoring of occupational exposure to bezziana and toluene

This study was carried out to evaluate the biological monitoring of occupational exposure to benzene and toluene in a total number of 31 male exposed workers and 30 control subjects. The present study showed a statistically significant higher level of biological indices of exposure [p < 0.01] of phenol and hippuric acid in urine of workers exposed to benzene and toluene than control subjects. Significant changes [p < 0.05, 0.01] in the levels of hematological and biochemical findings have been observed among exposed workers and control group. In addition, statistically significant higher levels of Mg, Mn and Ca were found among workers exposed to benzene and toluene while statistically significant lower levels of serum iron [p < 0.05] have been observed. No significant variations could be detected in the level of Zn and Cu between exposed and control subjects

Determinacao de orto-cresol urinario por cromatografia em fase gasosa utilizando-se detector de ionizacao de chama / Gas-chromatographic determination of orto-cresol in urine using flame ionization detector

O tolueno e um solvente aromatico com larga utilizacao industrial, sendo usado na fabricacao de varios produtos como cola, tiner, tintas e outras. Sua acao neurotoxica constitui-se no principal risco a saude dos trabalhadores, tornando-se indispensavel medidas de controle e avaliacao da exposicao ocupacional. A monitorizacao biologica do tolueno e realizada frequentemente, atraves da determinacao de seu principal produto de biotransformacao na urina, o acido hipurico, que esta tambem, presente em urina de individuos nao expostos ao solvente. Pequena fracao do tolueno absorvido e oxidado a compostos aromaticos incluindo o orto-cresol, o qual nao e encontrado significativamente, em urina de nao expostos. objetivando padronizar metodologia analitica para a determinacao deste metabolito em urina de individuos expostos e nao expostos ocupacionalmente ao tolueno, foi elaborado o presente trabalho. A tecnica selecionada foi a cromatografia em fase gasosa acoplada a detector de ionizacao de chama (CG/DIC). O metodo analitico apresentou boa precisao (CV intra e interensaio na faixa de 2,4 a 5,4 por cento) e recuperacao media de 98,0 por cento. O metodo apresentou linearidade na faixa de 0,2 a 3,0 micragrama/mL, sendo o limite de quantificacao o valor de 0,2 micragrama/ml

Effects of toluene exposure on ATPase activity in synaptosomal membranes of rat brain, "in vivo" and "in vitro" studies

Se presenta un trabajo de investigación en el cual se midió la actividad de la enzima Na+K+-ATPasa en la fracción sinaptosomal en cerebro de ratas de la Cepa Wistar expuestas en forma aguda (una exposición) y crónica (30 días consecutivos) a vapores de tolueno, (concentración de 15000 ppm en aire, durante 15 min.) en contraste con un grupo de ratas "control" expuestas al aire libre de tolueno, (estudio in vivo). Los estudios in vitro consistieron en la incubación de la fracción sinaptosomal de cerebro de rata en tubos cerrados conteniendo en el medio reactivo de tolueno a la concentración de 10mM. El cáculo de las constantes de Michaelis-Menten (Km y Vmax) fueron evaluadas en los estudios cinéticos de la enzima en las membranas sinaptosomales. Las ratas tanto de 50 como de 120 días de edad, que fueron expuestas en forma crónica a vapores de tolueno mostraron una reducción de la actividad entre 45 y 56 por ciento con respecto a la actividad del grupo control, siendo estadísticamente significativa (p<0.05). No habiendo diferencias en las ratas expuestas a tolueno en forma aguda. En los experimentos in vitro, también mostraron reducción en la actividad de la enzima podría ser un indicador de los efectos acumulativos de las propiedades físico-químicas del tolueno sobre las membranas biológicas

Efecto del tolueno en el desarrollo neuronal de crías de rata, cuyas madres fueron expuestas a inhalación crónica durante gestación o durante su adolescencia / Effects of the neural development of rat pups whose moters were exposed to toluene via chronic inhalation either during pregnancy or adolescence

Desarrollo neuronal en crios de rata adolescentes y gestantes expuestas a inhalación crónica de tolueno. Se sometieron a inhalación de tolueno a tres ratas jóvenes de 70 días de edad y nueve ratas gestantes de 90 días de edad durante 15 minutos por día desde la cruza hasta un día antes de la fecha de parto. Las ratas jóvenes se cruzaron después del período de inhalación con machos que no inhalaron el solvente. Las crias de las hembras tratadas, así como las de un grupo testigo fueron sometidas a iguales condiciones pero sin tolueno. Fueron sacrificadas por perfusión intracardíaca 24 crias de cada grupo, 12 de 14 días y 12 de 21 días de edad. Fue cuantificado el grado de ramificación de los procesos neuronales de las neuronas piramidales de la V capa de la corteza visual impregnadas con el método rápido de Golgi. Se encontró decremento significativo en las ramificaciones en la porción distal de la dendrita principal en los grupos expuestos al solvente comprarados con los grupos testigo y control

Toxicologia do tolueno: aspectos relacionados ao abuso / Toluene toxicology: abuse aspects

O tolueno está presente em muitos produtos de uso doméstico e industrial e é o principal solvente envolvido no abuso de substâncias e na exposiçäo ocupacional. O problema mais grave no estudo de patologias relacionadas ao tolueno é que este está geralmente associado, em suas preparaçöes comerciais, a outras substâncias. O potencial tóxico do tolueno foi abordado nos seguintes aspectos: parâmetros farmacológicos; características físico-químicas; exposiçäo; estudos clínicos; diagnóstico; pesquisa experimental; tolerância e dependência; efeitos agudos e crônicos; neurotoxicidade; teratogenicidade; doenças psiquiátricas; carcinogenicidade e tratamento. Conclui ser de grande importância e urgência que se realizem estudos clínicos com amostras maiores para definiçäo mais precisa das conseqüências do uso crônico

Exposiçäo ocupacional a agentes químicos em indústrias do Estado de Pernambuco / Occupational exposure to chemical agents in the industries of the State of Pernambuco

Levantamento dos níveis biológicos de exposiçäo ao chumbo,benzeno,tolueno e xileno, em amostras de indivíduos ocupacionalmente expostos. Das amostras de sangue analisadas para chumbo 40 por cento apresentaram valores superiores ao limite de tolerância biológica(LTB) estabelecido, ficando evidenciada uma alta exposiçäo ao metal

Effect of xylene, toluene and methyl alcohol on liver collagenesis in rats.

Among the three important industrial solvents used, maximum stimulation of collagen formation in rat liver was caused by methyl alcohol followed by toluene and xylene. A combined treatment also promoted collagenesis suggesting a synergistic effect of these solvents.

Efecto del tolueno en espinas dendríticas descendientes de ratas tratadas en la adolescencia o la gestación / Effects in dendritic spines in rats with a chronic exposure to tolueno

La inhalación crónica de tolueno causa lesiones microscópicas en el sistema nervioso central, tales como acanalamieto del tallo de las neuronas piramidales, hipertrofia neurofibrilar. Tres ratas Wistar jóvenes fueron expuestas a tolueno durante 21 días antes del apareamiento. Otras tres ratas hembras inhalaron vapores de tolueno desde el día 5 hasta el día 21 de la gestación. Después del tratamiento durante 15 minutos/día doce crías de cada grupo se sacrificaron a los 14 y 21 días de edad. Se determinó el número de espinas de la dendrita principal en segmento de 50 micras, de neuronas piramidales de la corteza visual en preparaciones de Golgi. Se encontró reducción significativa del número de espinas dendríticas en los grupos expuestos a tolueno en comparación con animales mantenidos bajo condiciones normales de laboratorio o del grupo sometido a las mismas condiciones pero sin tolueno.

Diferentes concentraciones de tolueno provocan el síndrome serotonérgico / Different concentrations of toluene inducing serotonergic syndrome

Los efectos sobre la conducta observados durante la inhalación de "thiner" han sido atribuidos al tolueno. Diversos estudios definen al tolueno como una droga alucinógena, que ejerce su efecto probablemente a través de mecanismos serotonérgicos. En este trabajo se estudia el efecto de la exposición aguda a diferentes concentraciones de tolueno en la presentación del síndrome serotonérgico. Grupos de ratas macho Wistar fueronm expuestos a diversas concentraciones de tolueno durante 15 minutos por única vez, mediante un sistema estático de inhalación. Se registró la presencia de los signos que integran al síndrome serotonérgico; además se evaluó el reflejo de enderezamiento. La concentración efectiva media de tolueno para provocar el síndrome serotonérgico fue de 4,878 ppm. El efecto observado sobre el reflejo de enderezamiento fue la perdida de éste a partir de 7,638 ppm; el efecto se incrementó de manera dependiente de la concentración