Câncer de colo uterino associado a fatores de risco ocupacional* / Cervical cancer related to occupational risk factors: review

Introdução: Fatores de risco associados ao trabalho podem causar, entre outros, câncer de colo uterino. Objetivo: Identificar na literatura especializada a associação entre câncer de colo de útero e a exposição aos fatores ocupacionais de risco. Métodos: Realizou-se um levantamento bibliográfico em bases de dados eletrônicos com os seguintes descritores: câncer de colo uterino e riscos ocupacionais. Resultados: Trabalhadores expostos ao tabaco nas fábricas de cigarro, fluidos de motores, exposição ocupacional a fungos e bactérias e ao tetracloroetileno, presente em produtos de limpeza usados em lavanderias e para desengraxar metais, estariam mais susceptíveis ao desenvolvimento de câncer de colo uterino. Conclusão: Há poucos estudos que identificam a relação entre o câncer de colo de útero e os fatores de risco ocupacional, dificultando a associação entre o carcinogênese e o fator de risco.

Background: Occupational risk factors are associated with many types of neoplasms including cervical cancer. Objective: To review the specialized literature for evidence on the relationship between cervical cancer and exposure to occupational hazards. Methods: Literature search in electronic databases using keywords cervical cancer and occupational risk. Results: Workers occupationally exposed to tobacco, fungi or bacteria, metalworking fluids and tetrachloroethylene used in dry cleaning and for metal degreasing exhibited higher susceptibility to cervical cancer. Conclusion: Few studies sought to investigate relationships between cervical cancer and occupational hazards, which hinders the attempts at establishing a causal link.

Protective effect of Mollugo nudicaulis Lam. on acute liver injury induced by perchloroethylene in experimental rats

OBJECTIVE@#To evaluate the protective effect of ethanol extract of Mollugo nudicaulis (M. nudicaulis) against perchloroethylene-induced hepatotoxicity.@*METHODS@#The hepatoprotective activity of the ethanol extract of M. nudicaulis (200 mg/kg body wt) was studied in percholoroethylene (1 000 mg/kg body wt) induced hepatotoxicity in Wistar albino rats. The serum levels of AST, ALT, ALP, bilirubin and the liver content of SOD, CAT, GPx, GST, GSH, vitamin C were assessed to evaluate the hepatoprotective and antioxidant activities of the extract. The activity of the extract was compared with silymarin, a standard reference drug. In addition, serum urea, uric acid and creatinine levels were measured to evaluate the kidney function. The histopathological examination of the liver tissues was observed to support the biochemical parameters.@*RESULTS@#The results revealed that the extract significantly (P<0.05) restored the serum levels of AST, ALT, ALP, bilirubin and significantly (P<0.05) increased the antioxidant enzymes SOD, CAT, GPx, GST, GSH, vitamin C in perchloroethylene-induced rats to its normalcy. The biochemical observations were supported by the histopathological studies of the liver tissues.@*CONCLUSIONS@#The results led to the conclusion that M. nudicaulis possess hepatoprotective and antioxidant activities against perchloroethylene-induced hepatotoxicity in rats.

Malignant Tumors of the Female Reproductive System

This review summarizes the epidemiology of cancer of the female reproductive system and associated lifestyle factors. It also assesses the available evidence for occupational factors associated with these cancers. Cervical, endometrial, and ovarian cancers are relatively common, and cause significant cancer morbidity and mortality worldwide, whereas vulvar, vaginal, fallopian tube cancers, and choriocarcinomas are very rare. As several lifestyle factors are known to play a major role in the etiology of these cancers, very few published studies have investigated possible relationships with occupational factors. Some occupational exposures have been associated with increased risks of these cancers, but apart from the available evidence on the relationships between asbestos fibers and ovarian cancer, and tetrachloroethylene and cervical cancer, the data is rather scarce. Given the multifactorial nature of cancers of the female reproductive system, it is of the utmost importance to conduct occupational studies that will gather detailed data on potential individual confounding factors, in particular reproductive history and other factors that influence the body's hormonal environment, together with information on socio-economic status and lifestyle factors, including physical activity from multiple sources. Studies on the mechanisms of carcinogenesis in the female reproductive organs are also needed in order to elucidate the possible role of chemical exposures in the development of these cancers.

Effectiveness of three solvents and two associations of solvents on gutta-percha and resilon

This study evaluated the effectiveness of 3 solvents (Citrol orange oil, Eucalyptol and Tetrachloroethylene) and 2 associations of solvents (Citrol orange oil+Tetrachloroethylene and Eucalyptol+Tetrachloroethylene) on 3 types of gutta-percha (conventional, thermoplastic and EndoREZ) and Resilon. Ten discs (10 mm diameter x 1 mm thick) from each material were prepared using standard metallic molds. Each specimen was weighed to determinate its initial mass. The specimens were immersed in the solvents for 10 min, followed by immersion in distilled water for 20 min, and were then reweighed to obtain the final mass. The mean weight loss determined the solvent capacity. Data were analyzed by ANOVA and Tukey's test at 5 percent significance level. Tetrachloroethylene was the most effective on conventional gutta-percha (p<0.05). Tetrachloroethylene was also the most effective on thermoplastic gutta-percha, but it was not significantly different (p>0.05) from Eucalyptol+Tetrachloroethylene, Citrol+Tetrachloroethylene, and Citrol. All solvents and associations presented little effectiveness on Resilon. The association Eucalyptol+Tetrachloroethylene was the most effective on EndoREZ, but it did not differ significantly (p>0.05) from Citrol+Tetrachloroethylene and Tetrachloroethylene. All evaluated substances presented solvent action. Tetrachloroethylene improved the effectiveness of both Citrol and Eucalyptol.

Este estudo avaliou a efetividade de 3 solventes (Citrol, Eucaliptol e Tetracloroetileno) e 2 associações (Citrol+Tetracloroetileno e Eucaliptol+Tetracloroetileno) sobre 3 tipos de guta-percha (convencional, termoplástica e EndoREZ) e Resilon. Dez discos (10 mm x 1 mm) de cada material foram preparados utilizando moldes metálicos. Cada espécime foi pesado para determinar a massa inicial. Os mesmos foram imersos nas soluções testadas por 10 min e em água destilada por 20 min. Os espécimes foram novamente pesados, agora para determinar a massa final. A perda média de peso determinou a capacidade solvente. Os dados foram analisados pelos testes ANOVA e Tukey. O tetracloroetileno foi o mais efetivo sobre a guta-percha convencional (p<0,05). Ele também foi o mais efetivo sobre a guta-percha termoplástica, mas sem diferença significativa para o Eucaliptol+Tetracloroetileno, Citrol+Tetracloroetileno e o Citrol (p>0,05). Todos os solventes e associações apresentaram pequena ação sobre o Resilon. A associação Eucaliptol+Tetracloroetileno obteve o melhor resultado sobre o EndoREZ, mas sem diferença significativa para o Citrol+Tetracloroetileno e o Tetracloroetileno (p>0,05). Todas as soluções apresentam ação solvente. O Tetracloroetileno melhorou a efetividade do Citrol e do Eucaliptol.

Acute Liver Failure Associated with Occupational Exposure to Tetrachloroethylene

Tetrachloroethylene is a chlorinated solvent that is primarily used in dry cleaning and degreasing operations. Although the hepatotoxicity caused by tetrachloroethylene has been well documented in literature, it is rarely considered as a cause of acute liver failure. We report a case of a 39-yr-old man who was admitted to our hospital for acute liver failure due to tetrachloroethylene exposure. Histological examination of the liver revealed massive hepatic necrosis, prominently, in zone 3 of the hepatic lobules. The patient underwent supportive treatment along with 3 sessions of plasmapheresis, and consequently, he presented a favorable outcome. Repeat liver biopsy performed 6 months after the patient's discharge showed architectural distortion with postnecrotic cirrhosis. Physicians should be aware of the possibility of acute liver failure induced by tetrachloroethylene. Early plasmapheresis can be effective for individuals with sufficient capacity for hepatocyte regeneration.

Neurotoxicity risk of repeated exposure to inhalants: potential role of melatonin and vitamin B as neuron protectors

The main objective of the current study was to elucidate the neurotoxic effects induced by repeated exposure to gasoline, perchloroethylene or toluene on male rats. The study was extended to evaluate the interventive role of melatonin, folic acid and vitamin B12 against the neurodegenerative insult produced by inhalants abuse. Ten experimental groups were assigned as follows: group [1] control group; group[2] The rats were exposed to gasoline vapors [3200 ppm] for quarter an hour / day; group [3] The rats were exposed to gasoline vapors then treated with melatonin [10 mg / kg b. wt]; group [4] The rats were exposed to gasoline vapors then treated with folic acid [200 mg / kg b. wt] and vitamin B12 [o.o4 mg / kg b.wt]; group [5] The rats were exposed to perchloroethylene vapors [800 ppm] for quarter an hour/day; group [6] The rats were exposed to perchloroethylene vapors then treated with melatonin; group [7] The rats were exposed to perchloroethylene vapors then treated with folic acid and vitamin B12; group [8]. The rats were exposed to toluene vapors [1000 ppm] for quater an hour / day; group [9] The rats were exposed to toluene vapors then treated with melatonin and group [10] The rats were exposed to toluene vapors then treated with folic acid and vitamin B12. The experiment was extended for 45 days. Brain lipid peroxidation, reduced glutathione, serotonin, dopamine, and GABA were measured. In addition, plasma total testosterone and DHEA-S were determined. Histopathological investigation of the brain tissue was also carried out. The results demonstrated that inhalation of gasoline, perchloroethylene, or toluene causes elevation of brain lipid peroxidation, GABA and plasma DHEA-S levels. However, these inhalants induced depletion of brain reduced glutathione, serotonin, dopamine as well as plasma total testosterone levels. Histopathological alterations in the brain of the rats exposed to inhalants were also observed. On the other hand, marked improvement was detected on treatment of the exposed rats with either melatonin or folic acid and vitamin B12. Melatonin supplementation exerted a better modulatory effect on the most of the measured parameters in rats exposed to gasoline than rats exposed to gasoline and treated with folic acid and vitamin B12. Rats exposed to perchloroethylene or toluene then treated with folic acid and vitamin B12 revealed more pronounced improvement in the most of biochemical parameters than that detected by melatonin treatment. Histopathological investigation of the brain revealed that the treatment of rats exposed to gasoline with melatonin produced more pronounced modulatory effect than that in case of treatment with folic acid and vitamin B12 as indicated by the appearance of healthy neurons and astrocytes. However, treatment with folic acid and vitamin B12 to rats exposed to perchloroethylene showed more curative effect than that in case of treatment with melatonin as indicated by observing the neurons more or less like control. Also, the treatment with folic acid and vitamin B12 to rats exposed to toluene showed better effect than that in case of treatment with melatonin as indicated by the appearance of the neurons as much as control, except of few neurons that appeared with some degree of degeneration. The current results clearly indicated the serious effect of inhalants on the central nervous system of rats. Treatment with melatonin or vitamin B was found to have a modulatory action against inhalant neurotoxicity

Growth inhibition in Japanese medaka (Oryzias latipes) fish exposed to tetrachloroethylene.

A recent study in our laboratory has demonstrated that tetrachloroethylene (TCE) is acutely toxic to Japanese medaka (Oryzias latipes) larvae with a 96 hr-LC50 of 18 (17-19) mg/mL (Spencer et al., 2002). In the present study we hypothesize that TCE exposure induces a developmental effect in Japanese medaka. Growth and age specific sensitivity of Japanese medaka larvae were studied with four age groups (7, 14, 21 and 28 days old) to determine tetrachloroethylene effects on these parameters. The medaka larvae were exposed for 96 hours in a single concentration (10 mg/mL) of TCE. The toxic endpoints evaluated were larvae weight, length, water content and protein concentration. The study revealed that exposure of medaka larvae to this sub-acute concentration of TCE significantly reduced length and weight in the treated group. The difference in growth between control and treated groups was more obvious in age versus length, than in age versus weight. The dry weight-fresh weight ratio (dw/fw) was shown to be higher in the control group. Water content in TCE-treated medaka was higher than in the control group, and younger fry had more water content than older ones. A higher protein concentration was also observed in TCE-treated medaka compared to the control group. These results indicate that TCE has a profound effect on the growth and development of Japanese medaka larvae.

Effects of TCE and PCE on cultured human keratinocyte lipid peroxidation and protective effect of vitamin E on it / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore the different concentrations of trichloroethylene (TCE) or perchloroethylene (PCE) induced cultured normal human epidermal keratinocyte (KC) lipid peroxidation and protective effect of Vitamin E on it.</p><p><b>METHODS</b>KC derived from 3 or more donors were pooled together and cultured with K-SFM. Neutral Red Uptake Assay was used to determine the IC50 of TCE or PCE, and then different concentrations of TCE or PCE were administered for culturing KC; 0.5 mmol/L TCE or 0.2 mmol/L PCE and different concentrations of Vitamin E were used to determine the protective effect of Vitamin E. After 4 hours' culture, kits were used to determine cellular MDA, SOD and ROS level.</p><p><b>RESULTS</b>Treatment of KC with different concentrations of TCE or PCE showed significant dose-related variations in lipid peroxidation, with the higher concentration, higher level of MDA, ROS and lower activity of SOD displayed in this study. Vitamin E 10 - 200 mmol/L dose-dependently attenuated MDA and ROS level, and increased SOD activities.</p><p><b>CONCLUSION</b>TCE or PCE can induce the lipid peroxidation in cultured KC and Vitamin E protects it from TCE- or PCE-induced peroxidation.</p>

Anaerobic degradation of tetrachloroethylene using different co-substrates as electron donors / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To investigate the biodegradation of tetrachloroethylene (PCE) by acclimated anaerobic sludge using different co-substrates, i.e., glucose, acetate, and lactate as electron donors.</p><p><b>METHODS</b>HP-6890 gas chromatograph (GC) in combination with auto-sampler was used to analyze the concentration of PCE and its intermediates. Results PCE could be degraded by reductive dechlorination and the degradation reaction conformed to the first-order kinetic equation. The rate constants are k(lactate) > k(glucose) > k(acetate). The PCE degradation rate was the highest in the presence of lactate as an electron donor.</p><p><b>CONCLUSION</b>Lactate is the most suitable electron donor for PCE degradation and the electron donors supplied by co-metabolic substrates are not the limiting factors for PCE degradation.</p>

A Case of Acute Tetrachloroethylene Poisoning Complicated by Acute Renal Failure / 대한신장학회잡지

Tetrachloroethylene is widely used as a solvent for degreasing operations and for dry cleaning. Accidental overexposure of tetrachloroethylene produces central nervous system depression which may be followed by hepatic and renal damage. Renal changes are usually mild and reversible with removal of the offending agent. The relationship between exposure to tetrachloroethylene and chronic renal failure remains controversial. Acute or subacute tetrachloroethylene poisoning has been occasionally observed in dry cleaners and fatal cases have been rarely reported. We experienced a case of acute tetrachloroethylene poisoning complicated by acute renal failure. After ingestion of 200 mL tetrachloroethylene, a 32- year-old man was admitted to the clinic in semicoma. Under the conservative treatment, the clinical condition of the patient improved consideravely, but acute renal failure developed. After 5 times hemodialysis during the admission, he recovered completely from acute renal failure.

Effects of tetrachloroethylene and vitamin E on renal parenchyma of albino rats

To evaluate the role of vitamin 'E' against tetrachloroethylene induced nephropathies. Fifty adult albino rats of either sex were divided into five equal groups; normal control [A], sesame oil control [A2], tetrachloroethylene treated group [B], experimental group [C] and vitamin 'E' control [D], In group C vitamin 'E' [10 mg/animal] was injected simultaneously with tetrachloroethylene [3mg/kg] for 15 days. On completion of treatment all the animals were sacrificed. There kindneys removed, processed for paraffin embedding and stained with H and E, PAS and Alcian Blue. Simultaneous administration of vitamin 'E' and tetrachloroethylene showed unaltered morphology of renal cortical parenchyma, comparable with that of group A1, A2 and D kidneys, except slight proximal tubular dilatation. Tetrachloroethlene induced nephropathy may partially be prevented by simultaneous administration with vitamin 'E' in albino rats

Tetrachorethylene treatment of ankylostomiasis

Although it may be reasonably inferred from our meager experience that tetrachlorethylene is a safe and efficacious anthelminthic, we do not hold this its effectiveness should not be further investigated. (Conclusion)

A Study for Cardiovascular Malformations and Functional Changes Induced by Tetrachloroethylene in Developing Chick Embryos / 대한해부학회지

Chlorinated solvents are recognized as well-known drinking water contaminants and potent teratogens for developing embryos. Among theses compounds, tetrachloroethylene was studied to evaluate the teratogenic effects in detail. This study was also undertaken to understand the teratogenetic mechanisms by assessing the relationship between the physiological impairments and cellular degeneration including apoptosis induced by tetrachloroethylene, and the cardiovascular malformations. Fertilized white leghorn eggs (n=530) were incubated for 90~96 hours up to Hamburger-Hamilton stage 27~28. To the experimental group, tetrachloroethylene was dissolved in mineral oil at concentrations of 40 micrometer and 50 micrometer and was injected into the chorioallantoic membrane. One half of the control was injected with saline and the other half with mineral oil. The experimental animals are studied for ECG changes, and light and electron microscopic observation. Two silver thread electrodes were used to record the ECG. ECG changes were recorded for 6~30 minutes after tetrachloroethylene injections. In parallel studies, blood velocity through the dorsal aorta was measured by a pulse Doppler velocity meter with 20 MHz probe. The specimens were stained with hematoxylin and eosin for light microscopic study and the Hitachi H-800 EM was used for transmission electron microscopic evaluation. The embryos underwent formalin fixation on day 14, and the presence of malformations was observed by a microscopy. The results obtained are as follows: Repeated injections of 40~50 micrometer tetrachloroethylene appeared to have a strong influence on the formation of cardiovascular malformations. Various types of cardiac malformations were observed in the experimental group compared to control group, that were statistically significant (p<0.01) and many embryos also died. The malformations observed were large ventricular septal defect, endocardial cushion defect, double outlet right ventricle and truncus arteriosus associated with single ventricle. Large ventricular septal defect was most common type of cardiovascular abnormalities. Arrythymias including ventricular fibrillations were evident on ECG 6~30 minutes after the injections. Blood flow through the dorsal aorta was markedly decreased in concordance with the ECG changes. A large amount of individual cell death suggesting apoptosis was seen on light microscopic evaluation and the electron microscope revealed cellular degeneration of the embryonic myocardium. We concluded that tetrachloroethylene, like other chloride compounds has potent teratogenic effects. The cardiac malformations were probably caused by decreased blood flow due to physiofunctional changes and cellular necrosis associated with apoptosis. By including birds and mammals in further experiments, we hope to elucidate an embry-ological clue into how early cardiovascular malformations are caused.

Development of Physiologically Based Pharmacokinetic Model for Several Volatile Organic Compounds / 대한산업의학회지

Recently physiologically based pharmacokinetic (PB-PK) model has important role in industrial and environmental health. One of problem in application of PB-PK models is that they have uncertainties that is due to different input parameters according to authors. In order to develope a PB-PK model that hag good validity, the effect of several input parameters on simulation results was studies. Chemicals studied were perchloroethylene, toluene and styrene. Simulation of alveolar concentration, blood concentration and urinary metabolites was performed for three solvents, respectively. Input parameters discusses were physiological parameters, metabolic parameters and partition coefficient of chemicals. By comparing simulation results according to several pairs of parameters with experimental data, input parameters that showed best fit were decided.

Alteraciones neuropsicológicas en trabajadores expuestos a neurotóxicos / Neuropsychological disorders in workers exposed to neurotoxics

La neurotoxicidad es un grave problema de salud pública debido al incremento de sustancias neurotóxicas y a la gran cantidad de trabajadores expuestos. Gran cantidad de sustancias de uso común en la industria. Tales como solventes, metales y plaguicidas, provocan alteraciones neurotóxicas a concentraciones por debajo de los límites permisibles, produciendo cambios importantes en la función psicológica y el comportamiento, que se expresan en trastornos funcionales que interfieren en las tareas cotídianas e incrementan la accidentabilidad. En este artículo se revisa la literatura científica sobre los efectos neurotóxicos de solventes, plomo, mercurio y plaguicidas, y se comentan aspectos metodológicos de interés para el diseño de investigaciones epidemiológicas. Como conclusión, es notoria la existencia de evidencias que demuestran el efecto neurotóxico de gran cantidad de sustancias usadas en la industria. Así mismo, consideramos importante continuar realizando investigaciones sobre el tema, y sobre todo, La necesidad de tomar medidas preventivas para proteger la salud del trabajador

1,1,1 - Tricloroetano, tricloroetileno, percloroetileno: aspectos toxicológicos / 1,1,1 - Trichloroethane, thichloroethylene, perchloroethylene: toxicologycal aspects

Säo solventes de ampla utilizaçäo industrial empregados, principalmente, nas operaçöes de desengraxamento de peças metálicas. O desenvolvimento significativo das indústrias mecânicas brasileiras sugere a larga utilizaçäo desses agentes e, consequentemente, um grande número de indivíduos expostos, sendo a exposiçäo ocupacional a principal causa de intoxicaçäo. Nesta revisäo objetivou-se apresentar as propriedades físico-químicas destas substâncias, as condiçöes que afetam suas biodisponibilidades químicas e seus efeitos tóxicos, conhecimentos necessários para a implantaçäo de um programa adequado de monitorizaçäo biológica.