Hematological Changes in Gas Station Workers.

(1) Background: Benzene, toluene, and xylene isomers (BTX) are present in gasoline. Exposure to benzene may lead to the appearance of a series of signs, symptoms, and complications, which are characterized by benzene poisoning, which is an occupational disease. This study evaluated the presence of signs and symptoms related to occupational exposure and whether occupational exposure to BTX is associated with the development of hematological changes. (2) Material and Methods: This cross-sectional epidemiological study included 542 participants, in which 324 were gas station workers (GSWs) and 218 were office workers (OWs) with no occupational exposure to benzene. To characterize the type of exposure (exposed and not exposed), trans,trans-Muconic acid (tt-MA), Hippuric acid (HA), and Methylhippuric acid (MHA) were used as exposure biomarkers. The tt-MA analysis revealed that the GSWs had 0.29 mg/g of urinary creatinine and the OWs had 0.13 mg/g of urinary creatinine. For HA, the GSWs presented 0.49 g/g of creatinine while the OWs presented 0.07. MHA analysis revealed that the GSWs had 1.57 g/g creatinine and the OWs had 0.01 g/g creatinine. Occupation habits and clinical symptoms were collected by questionnaire and blood samples were analyzed for hematological parameters. The persistence of hematological changes was evaluated with three serial blood collections every 15 days followed by laboratory hematological analysis. A descriptive analysis by the Chi-square test method was performed to evaluate the association between occupational exposure to fuels and the occurrence of changes in hematological parameters. (3) Results: In the GSWs, the most described signs and symptoms were somnolence (45.1%), headache (38.3%), dizziness (27.5%), tingling (25.4%), and involuntary movement (25%). Twenty GSWs that presented hematological alterations performed serial collections fifteen days apart. In addition, these workers presented total leukocyte counts above the upper limit and lymphocyte counts close to the lower limit. Leukocytosis and lymphopenia are hematological alterations present in chronic benzene poisoning. (4) Conclusions: The results found an initial change in different hematological parameters routinely used in clinics to evaluate health conditions. These findings reveal the importance of valuing clinical changes, even in the absence of disease, during the health monitoring of gas station workers and other groups that share the same space.

Risks related to the domestic laundering of filling station attendant uniforms: advances and uncertainties.

Gasoline is the most common transportation fuel in Brazil, with up to 1% of benzene. Benzene is a health-damaging organic solvent that is extensively used worldwide, being classified as a human carcinogen by the International Agency for Research on Cancer (Group 1). Many workers at filling stations are exposed to benzene, present in gasoline. The main routes of exposure and absorption of benzene are inhalation, oral, and dermal routes. The penetration and maintenance of benzene and other chemicals on personal protective equipment and clothing of workers who manipulate these solvents may increase their levels of exposure and offer risks to their family members, since contaminated clothing is laundered at their homes, which goes against legislative framework (Annex 2, Regulatory Standard No. 9). This way, the objective of this work was to discuss the importance of periodic changes and cleaning of filling station attendant uniforms performed by employers as preventive measures against the deterioration of the health of workers and their family members. We performed a narrative review; no systematic criteria were used in the search for national and international studies. After critical reading, we observed a lack of consistent data on this theme. Laundering of uniforms worn by filling station attendants should take place outside the domestic environment in order to protect the health of workers and their family members and avoid possible cross-contamination.

Evaluation of Exposure to Toluene and Xylene in Gasoline Station Workers.

The main volatile organic compounds found at gasoline stations are benzene, toluene, ethylbenzene, and xylene isomers (BTEX). They cause several harmful effects on human health. Regulatory Norm 7 (1978) provides that, in Brazil, biological monitoring of toluene and xylene is carried out by measuring the urinary metabolites hippuric acid (HA) and methylhippuric acid (MHA), respectively. The objective of this study was to assess the exposure to toluene and xylene and to identify related signs and symptoms in gasoline station workers. A cross-sectional epidemiological study was conducted with workers occupationally exposed to fuels. These gasoline station workers were divided into two groups: 94 workers exposed mainly by inhalation (convenience store workers (CSWs)) and 181 workers exposed by inhalation and dermal route (filling station attendants (FSAs)). A comparison group was formed by 119 workers not occupationally exposed to fuels (office workers (OWs)). Workers exposed to fuels had higher average levels of these exposure biomarkers (HA and MHA), which were also higher in convenience store workers than in filling station attendants. In addition, individuals exposed to the solvents present in gasoline had altered mood/depression, cramps, dizziness, drowsiness, headaches, irritability/nervousness, weakness, weight loss, and other symptoms more frequently and had higher urinary levels of HA and MHA compared to the comparison group. Gasoline station workers showed high levels of HA and MHA, reflecting high occupational exposure to the solvents toluene and xylene present in gasoline, demonstrating that changes in the current legislation and in the work environment are necessary to ensure better health protection for these workers.

Gasoline-station workers in Brazil: Benzene exposure; Genotoxic and immunotoxic effects.

Chronic exposure to benzene is a risk factor for hematological malignancies. Gasoline-station workers are exposed to benzene in gasoline, via both inhalation and dermal contact (attendants and managers) or inhalation (workers in the on-site convenience stores and offices). We have studied the exposure of these workers to benzene and the resulting genotoxic and immunotoxic effects. Levels of urinary trans, trans-muconic acid were higher among gasoline-station workers than among office workers with no known exposure to benzene (comparison group). Among the exposed workers, we observed statistically significant biological effects, including elevated DNA damage (comet assay); higher frequencies of micronuclei and nuclear buds (CBMN assay); lower levels of T-helper lymphocytes and naive Th lymphocytes; lower CD4 / CD8 ratio; and higher levels of NK cells and memory Th lymphocytes. Both groups of exposed workers (inhalation and inhalation + dermal routes) showed similar genotoxic and immunotoxic effects.

Analysis of Benzene Exposure in Gas Station Workers Using Trans,Trans-Muconic Acid.

In Brazil, gas station workers are occupationally exposed to the benzene present in gasoline. Brazilian law indicates the use of trans,trans-muconic acid(t,t-MA) as a biomarker of benzene exposure. The aim of this study was to evaluate the level of exposure to benzene in gas station workers, through the quantification of t,t-MA present in urine. A total number of 269 gas station workers divided into 179 filling station attendants exposed by inhalation and dermal route and 90 convenience store workers exposed only by inhalation were included. A control group was formed by 100 office workers, without occupational exposure to benzene. The urinary levels of t,t-MA were evaluated by HPLC with a UV detector. Gas station workers showed higher mean values of t,t-MA (0.204 mg/g creatinine; 95% CI 0.170-0.237) than office workers (0.126 mg/g creatinine; 95% CI 0.0817-0.1693). T,t-MA levels were higher in convenience store workers exposed to gasoline only by inhalation (0.221 mg/g creatinine; 95% CI 0.160-0.282), than in those exposed to gasoline by inhalation and dermal route-filling station attendants (0.195 mg/g creatinine; 95% CI 0.155-0.235). Gas station workers with a higher level of t,t-MA had epistaxis. T,t-MA values were higher in the Downtown (0.15 mg/g creatinine) region's workers than in the more affluent South Zone region's workers (0.07 mg/g creatinine). Smoking habits influenced the urinary t,t-MA values, while the frequency of consumption of industrialized and frozen foods showed no influence.

Interstrain differences in the expression and activity of Cyp2a5 in the mouse liver.

BACKGROUND: Cytochrome P450 2A5 (Cyp2a5), a mouse enzyme orthologous of human CYP2A6, catalyzes a number of toxicologically important reactions, including the metabolism of nicotine, aflatoxin B1, and several other xeno- and endobiotics. Cyp2a5 expression is complex and not yet fully understood. We investigated inter-strain differences in the activity and mRNA expression of hepatic Cyp2a5. Cyp1a1/2 and Cyp2b9/10 activities were evaluated for comparative purposes. Data on the interstrain differences in the expression and activity of Cyp2a5 are important to select a suitable mouse model for studying CYP2A6-mediated metabolism. RESULTS: Activity of Cyp2a5 (coumarin 7-hydroxylase) was highest in DBA-2 and DBA-1, intermediate in B6D2F1 (hybrid) and low in the remaining strains (C57BL/6, C57BL/10, CBA, BALB/cAn, SW). Contrasting with the activity, background levels of Cyp2a4/5 mRNA did not differ between high- and low-activity murine strains. Phenobarbital (PB, 80 mg/kg body weight/day × 3 days, i.p.) increased Cyp2a5, Cyp1a1/2 (ethoxyresorufin-O-deethylase) and Cyp2b9/10 (bezyloxyresorufin-O-debenzylase) activities while only Cyp2a5 was enhanced by pyrazole (PYR, 100 mg/kg body weight/day × 3 days, i.p.). Inductions of Cyp2a5 activity by PYR and PB were accompanied by increases of Cyp2a4/5 mRNA. PYR and PB did not upregulate heme oxygenase-1 (hmox-1) mRNA expression in any strain, a finding that is apparently at odds with the notion that Cyp2a5 and hmox-1 inductions are coordinated events. CONCLUSIONS: Since background levels of Cyp2a4/5 gene transcripts of high-activity strains did not differ from those of low-activity mice, distinct constitutive activities did not result from different transcription rates and/or mRNA half-lives. Results therefore suggested that interstrain differences in constitutive activity of Cyp2a5 possibly arise from distinct translation efficiencies, protein half-lives and/or enzyme kinetics toward the substrate. Data from this study indicated that all tested strains are suitable models for studying toxicants that are substrates for human CYP2A6; DBA-2, DBA-1 and the hybrid B62DF1, however, have the advantage of presenting high constitutive activities of Cyp2a5.

Vigilância sanitária em postos de revenda de combustíveis: aplicação de um modelo para integrar ações e promover a saúde do trabalhador / Health surveillance in gas stations: application of a model to integrate actions and promote worker’s health

Resumo Introdução: o benzeno, composto encontrado na gasolina, é reconhecido como agente cancerígeno e tem sido objeto de controle em âmbito mundial devido aos seus efeitos agudos e crônicos à saúde humana. No Brasil, trabalhadores de postos de revenda de combustíveis (PRC) são expostos ao benzeno durante suas atividades ocupacionais. A Vigilância Sanitária, ao monitorar a exposição dos trabalhadores ao benzeno, pode avaliar os riscos e implementar estratégias para estabelecer um ambiente de trabalho mais seguro. Objetivo: suscitar a discussão sobre as ações da Vigilância Sanitária em postos de combustíveis baseada na aplicação do modelo Força-Motriz/Pressão/Situação/Exposição/Efeito/Ação (FPSEEA). Método: realização de uma ampla revisão da literatura com a finalidade de obter as informações necessárias para construção e desenvolvimento da matriz proposta no modelo. Discussão: foi possível identificar as deficiências existentes nos diferentes níveis institucionais que possuem suas ações voltadas à proteção da saúde do trabalhador e propor ações para avançar na reflexão sobre o modelo de desenvolvimento, modos de produção e exploração de recursos. Também foram identificadas as possíveis ações da Vigilância Sanitária a serem aplicadas no ambiente ocupacional de PRC para eliminação ou redução dos riscos à saúde aos quais os trabalhadores estão expostos.

Abstract Introduction: benzene, a compound found in gasoline, is recognized as a carcinogen, and it has been controlled worldwide because of its acute and chronic effects to human health. In Brazil, gas station (GS) attendants are exposed to benzene during their occupational activities. Health Surveillance, when monitoring the workers’ exposure to benzene, can assess the risks and implement strategies to establish a safer working environment. Objective: to evoke the discussion about Health Surveillance actions in gas stations based on the application of the Driving Force/Pressure/State/Exposure/Effects/Action (DPSEEA) model. Method: we developed the matrix proposed by the DPSEEA model using information from literature review. Discussion: we were able to identify the existing shortcomings in the different institutional levels that have actions directed to workers’ health protection. We also proposed actions for enhancing the discussion on the development model, modes of production, and resources exploitation. We also identified the possible Health Surveillance actions to be applied in the GS occupational environment to eliminate or reduce the health risks to which workers are exposed.

Prenatal exposure to the phytoestrogen daidzein resulted in persistent changes in ovarian surface epithelial cell height, folliculogenesis, and estrus phase length in adult Sprague-Dawley rat offspring.

Daidzein (DZ), an isoflavone with the potential to interfere with estrogen signaling, is found in soy products, which have gained popularity due to purported beneficial effects on the cardiovascular and skeletal systems and potential antineoplastic properties. However, the ingestion of phytoestrogens has been associated with impaired reproductive function in many species. The aim of this study was to determine the long-term effects on the ovaries of rat offspring exposed to DZ or ethinyl estradiol (EE) during prenatal development. Gravid rats were administered either vehicle or 5 or 60 mg DZ/kg body weight/d or 0.002 mg 17-α EE /kg body weight/d on gestational days 6-21. Ovarian-related endpoints were investigated during adulthood in female offspring. The mean cell height of the ovarian surface epithelium was significantly reduced in all treated groups. Alterations in folliculogenesis included increased follicular atresia, a reduction in secondary and tertiary follicle numbers, and cyst formation. An elevated prevalence of a slightly prolonged estrus phase was also observed. The morphological changes to the ovarian surface epithelium are consistent with an antiproliferative effect, while ovarian folliculogenesis was adversely affected. The effects of the high dose DZ were similar to those observed with 17-α EE.

Modulation of cytochrome P450 2A5 activity by lipopolysaccharide: low-dose effects and non-monotonic dose-response relationship.

Mouse cytochrome P450 (CYP) 2A5 is induced by inflammatory conditions and infectious diseases that down-regulate the expression and activity of most other CYP isoforms. Enhanced oxidative stress and nuclear factor (erythroid 2-related factor) 2 (Nrf2) transcription factor activation have been hypothesised to mediate up-regulation of CYP2A5 expression in the murine liver. The unique and complex regulation of CYP2A5, however, is far from being thoroughly elucidated. Sepsis and high doses of bacterial lipopolysaccharide (LPS) elicit oxidative stress in the liver, but depression, not induction, of CYP2A5 has been observed in studies of mice treated with LPS. The foregoing facts prompted us to evaluate the response of CYP2A5 liver activity in female DBA-2 mice over a broad range of LPS doses (0, 0.025, 0.05, 0.1, 0.2, 0.5, 1, 2, 5, 10, and 20 mg/kg). Cytokine levels (interleukin [IL]-2, IL-4, IL-6, IL-10, IL-17A, interferon gamma, tumour necrosis factor alpha) and nitric oxide (NO) were measured in the blood serum. Activities of CYP1A (EROD) and CYP2B (BROD) in the liver were also determined for comparative purposes. LPS depressed CYP2A5 at low doses (0.025-2.0 mg/kg) but not at doses (>2 mg/kg) that increased pro-inflammatory cytokines and NO serum levels, and depressed CYP1A and CYP2B activities. Blockade of pro-inflammatory cytokines and the overproduction of NO induced by co-treatment with pentoxifylline and LPS and iNOS inhibition with aminoguanidine both extended down-regulation of CYP2A5 to the high dose range while not affecting LPS-induced depression of CYP1A and CYP2B. Overall, the results suggested that NO plays a role in the reversal of the low-dose LPS-induced depression of CYP2A5 observed when mice were challenged with higher doses of LPS.

Regulação de Cyps hepáticas, Cyp2a5, 1a1/2 e 2b9/10, pelo LPS e diferenças de expressão e atividade entre linhagens de camundongos / Regulation of hepatic CYPs, Cyp2a5, 1a1 / 2 and 2b9/10 by LPS and differences in expression and activity among mouse strains

Nas últimas quatro décadas estudos mostram que inflamações e infecções modulam a expressão e atividade de enzimas citocromo P450 (CYP). A modulação negativa das atividades de CYPs hepáticas é o efeito mais frequente, mas a regulação positiva também tem sido relatada. Entretanto, os mecanismos pelos quais estímulos inflamatórios e infecções modulam a expressão e a atividade destas enzimas de biotransformação permanecem obscuros. Este estudo foi conduzido para ajudar a esclarecer os mecanismos pelo quais Cyp2a5, 1a1/2 e 2b9/10 são reguladas no tecido hepático quando a resposta imune é ativada. Na primeira parte do trabalho, avaliamos a expressão e atividade constitutiva e induzida de Cyp2a5 em camundongos fêmeas adultas de oito linhagens/colônias. Possíveis relações da indução de Cyp2a5 com a expressão aumentada da heme-oxigenase 1 (HO-1) e dano hepático também foram investigadas. Níveis de mRNA da Cyp2a4/5 e hmox-1 no tecido hepático foram determinados por qPCR, enquanto as atividades da COH (Cyp2a5), EROD (Cyp1a1/2) e BROD (Cyp2b9/10) foram avaliadas em microssomos hepáticos, e a toxicidade hepática provocada pelo tratamento com os indutores examinada medindo os níveis séricos de transaminase (ALT). Os resultados mostraram que os níveis constitutivos da atividade de Cyp2a5 variaram acentuadamente entre as linhagens, sendo a atividade mais elevada registrada em DBA-2, mas os níveis constitutivos de mRNA de Cyp2a4/5 e a expressão de HO-1 não apresentaram grandes variações. O pirazol (PIR) induziu a expressão e atividade de Cyp2a5 em todas as linhagens, o fenobarbital (FEN) apenas no DBA-2, enquanto a expressão de HO-1 não foi alterada pelos tratamentos. Em contraste com o observado com Cyp2a5, as atividades constitutivas de Cyp1a1/2 e 2b9/10 exibiram apenas discretas variações entre as linhagens. O PIR praticamente não teve efeito sobre EROD e BROD, mas o FEN regulou positivamente as atividades de Cyp1a1/2 e 2b9/10. A hepatotoxina PIR induziu a expressão e atividade de Cyp2a5 em doses em que não provocou qualquer aumento de ALT. Na segunda parte do trabalho, avaliamos os efeitos do LPS sobre a atividade de Cyp2a5, 1a1/2 e 2b9/10 em fêmeas DBA-2, e investigamos se o bloqueio da resposta inflamatória, com a administração concomitante de pentoxifilina (PTX), atenuaria ou aboliria os efeitos do LPS. Os resultados mostraram que o LPS deprimiu as atividades de Cyp1a1/2 e 2b9/10 apenas em doses altas, mas o efeito sobre a atividade de Cyp2a5 seguiu uma curva dose-resposta não linear e não monotônica (forma de “U”, com depressão em doses baixas, retornando aos níveis basais com as doses mais altas). A atenuação do aumento da produção de citocinas e NO pelo co-tratamento LPS e PTX não alterou os efeitos da endotoxina sobre as atividades de Cyp1a1/2 e 2b9/10, sugerindo que a regulação negativa não depende do aumento dos níveis de NO e citocinas no sangue. O co-tratamento, todavia, modificou os efeitos relacionados à dose de LPS sobre a atividade de Cyp2a5: a depressão pelas doses baixas de LPS foi mantida, mas prolongou-se a extensão da faixa de doses em que o LPS causa depressão de COH, mostrando que o co-tratamento pareceu abolir a volta aos níveis quase basais de atividade de Cyp2a5 notado em doses altas. Por outro lado, o bloqueio da produção de NO pelo co-tratamento com LPS e aminoguanidina (Ag, inibidor seletivo de NOS2) mostrou que o retorno da atividade de Cyp2a5 aos níveis basais em doses altas de LPS foi abolido. A partir dos resultados aqui apresentados, é possível supor que os níveis aumentados de NO de alguma forma deflagram a transição da regulação negativa para a positiva da atividade de Cyp2a5.

Malaria infection modulates effects of genotoxic chemicals in the mouse bone-marrow micronucleus test.

Malaria has been reported to modulate the activity of cytochrome-P450 enzymes (CYP). Since CYPs are involved both in the activation and detoxication of xenobiotics, we investigated whether malaria would modify the effects of chemical carcinogens in the bone-marrow micronucleus assay. Female C57BL6 mice were infected with Plasmodium berghei (ANKA) and treated (ip route) with cyclophosphamide (CPA, 25 mg/kg body weight), 7,12-dimethylbenz[a]anthracene (DMBA, 50mg/kg body weight) or ethyl methanesulfonate (EMS, 150 mg/kg body weight), on post-infection days 9-12 when parasitemia was > or =9% of RBC. Controls were age-paired non-infected mice. Bone marrows were sampled at 24 and 48 h (CPA), 24 h (EMS) or 48 h (DMBA) after treatment. The background incidence of polychromatic erythrocytes with micronuclei (MN-PCE) in malaria-infected mice was approximately twofold the background incidence in non-infected controls. Effects of indirect clastogens (CPA and DMBA) in the micronucleus assay were attenuated while the effect of EMS, a direct clastogen, was enhanced by infection. In a separate experiment, malaria was shown to decrease activities of ethoxy-(EROD, a marker for CYP1A) and benzyloxy-(BROD, CYP2B) resorufin-O-dealkylases in liver microsomes. The foregoing findings are consistent with the hypothesis that malaria-caused attenuation of genotoxicity arose from a down modulation of CYP isoforms that convert CPA (CYP2B) and DMBA (CYP1A) into their active metabolites.

Avaliação do efeito genotóxico do megazol / Evaluation of the genotoxic potential of MGZ

As tripanossomíases americana (doença de Chagas) e africana (doença do sono) são causadas por protozoários do gênero Trypanosoma, têm como vetores insetos hematófagos e exibem alta morbidade. As duas tripanossomíases estão entre as doenças humanas mais negligenciadas porque, em que pese a relevância de ambas em termos de saúde pública, não foi feito esforço importante para desenvolver medicamentos eficazes e seguros, principalmente para os estágios mais tardios quando os protozoários atingem e comprometem órgãos vitais como o coração e o SNC. O megazol (MGZ) é um derivado nitroimidazólico com potente atividade contra os tripanossomas. O MGZ poderia ser considerado uma alternativa promissora aos fármacos atualmente empregados, não fossem os indícios de efeito genotóxico, problema freqüente entre os derivados nitroimidazólicos. Situado neste contexto, o objetivo deste trabalho foi reavaliar o potencial genotóxico do MGZ, e iniciar uma série de estudos para verificar se é possível bloqueá-lo com substâncias antimutagênicas, sem comprometer a eficácia tripanossomicida. A avaliação da genotoxicidade do MGZ foi realizada com ensaios in vitro, i.e., indução de aberrações cromossômicas em linfócitos humanos em cultura, e também in vivo, i.e., indução de micronúcleos em células da medula óssea de camundongos. (...) Os resultados obtidos neste trabalho confirmaram que o MGZ é genotóxico. Os resultados do ensaio in vivo sugerem porém que a biodisponibilidade do fármaco administrado por via oral é reduzida. A investigação in vitro do antagonismo da genotoxicidade do MGZ pela vitamina E foi até certo ponto prejudicada pela acentuada citotoxicidade das concentrações de vitamina E (VTE) empregadas (2,5∙10-6M e 5,0∙10-6M). Apesar da pronunciada redução do índice mitótico dos linfócitos humanos em cultura, os resultados sugeriram que o efeito clastogênico induzido pelo MGZ 2,81∙10-4M foi discretamente atenuado. Os efeitos da VTE, e de outras substância...