Chlorpyrifos should be banned in agriculture and livestock production in Colombia

Chlorpyrifos (CPF) is a pesticide widely used in Colombia´s agriculture, including crops, farm animals and pets, despite it has been banned for use in the European Union and the United States. Studies demonstrate that even low blood levels of CPF -which do not inhibit blood acetylcholinesterase- can lead to child developmental and neurological disorders such as smaller head circumference and brain alterations, and psychomotor and cognitive deficits related to learning ability, attention and memory. In adults, CPF is an endocrine disruptor and breast carcinogen. High direct and indirect economic costs have been associated with CPF exposure. Not only farmers and their families -who have the highest exposures- but the general population consuming crops sprayed with CPF are also at risk. For these reasons CPF was recently banned by the European Union (2020) and the USA (2021). Pesticide regulation policies vary greatly depending on which and how scientific studies are used to assess health risks. Pesticide evaluations funded by the chemical industry should be rectified to avoid conflicts of interest. Furthermore, political alignment with the interests of the industry should not take precedence over independent scientific evidence. It is discouraging, to say the least, that until stricter health laws are passed in Colombia, CPFs and related pesticides will continue to be imported from those countries that have already banned them. Colombian scientists should raise their voice to challenge blind acceptance of profits over unintended consequences, and efforts to prevent pesticide´s abuse should be encouraged.

El clorpirifos (CPF) es un pesticida ampliamente utilizado en la agricultura de Colombia, incluidos cultivos, animales de granja y mascotas, a pesar de haber sido prohibido en la Unión Europea y Estados Unidos. Los estudios han demostrado que incluso niveles bajos de CPF en sangre -que no inhiben la acetilcolinesterasa sanguínea- pueden provocar trastornos neurológicos y del desarrollo infantil, como menor circunferencia de la cabeza y alteraciones cerebrales, y déficits psicomotores y cognitivos relacionados con la capacidad de aprendizaje, la atención y la memoria. En adultos, el CPF es un disruptor endocrino y causante de cáncer de mama. Altos costos económicos directos e indirectos se han asociado con la exposición al CPF. No solo los trabajadores agrícolas y sus familias, que están más expuestos, sino también la población en general que consume cultivos rociados con CPF también están en riesgo. Por estas razones el CPF fue prohibido recientemente por la Unión Europea (2020) y los EE. UU. (2021). Las políticas de regulación de plaguicidas varían mucho según los estudios científicos escogidos para evaluar los riesgos para la salud. Las evaluaciones de plaguicidas financiadas por la industria química deben rectificarse para evitar conflictos de interés. Además, ante la evidencia científica independiente no debería prevalecer la alineación política con los intereses de dicha industria. Es desalentador, por decir lo menos, que hasta que se aprueben leyes de salud más estrictas en Colombia se seguirán importando CPF y pesticidas relacionados desde aquellos países que ya los han prohibido. Los científicos colombianos deben alzar la voz para desafiar la aceptación ciega de ganancias por encima de las consecuencias no deseadas en salud pública, y se deben alentar los esfuerzos para prevenir el abuso de pesticidas.

Clorpirifós (CPF) é um pesticida registrado amplamente utilizado na agricultura colombiana, incluindo lavouras, animais de fazenda e animais de estimação, apesar de ter sido proibido na União Europeia e nos Estados Unidos. Estudos têm demonstrado que mesmo níveis baixos de CPF no sangue -que não inibem a acetilcolinesterase sanguínea-podem levar a distúrbios neurológicos e de desenvolvimento em crianças, como menor perímetro cefálico e alterações cerebrais, além de déficits psicomotores e cognitivos relacionados à capacidade de aprendizagem, atenção e memoria. Em adultos, o CPF é um desregulador endócrino e cancerígeno da mama. Altos custos econômicos diretos (devido ao tratamento) e indiretos (devido à perda de produtividade) têm sido associados à exposição ao CPF. Não apenas os trabalhadores agrícolas e suas famílias, que têm as maiores exposições, mas a população em geral que consome culturas pulverizadas com CPF também estão em risco. Por essas razões, o CPF foi recentemente proibido pela União Europeia (2020) e pelos EUA (2021). As políticas de regulamentação de pesticidas variam muito, dependendo de quais (e como) os estudos científicos são usados para avaliar os riscos à saúde. As avaliações de pesticidas financiadas pela indústria química devem ser retificadas para evitar conflitos de interesse. Além disso, o alinhamento político com os interesses da indústria não deve ter precedência sobre as evidências científicas independentes. É desanimador - para dizer o mínimo - que até que leis de saúde mais rígidas sejam aprovadas na Colômbia, o CPF e tóxicos relacionados continuarão a ser importados dos países que já os proibiram.

Telomere length and telomerase: early biomarkers for environmental carcinogen exposure / 中国职业医学

Telomere is a DNA-protein complex located at the end of linear chromosome of eukaryotic cells, which has the function of stabilizing chromosome. The change of telomere length is closely related to the exposure to environmental carcinogens. The repair and elongation of telomere rely on the catalysis and mediation of telomerase. Exposure to typical environmental carcinogens polycyclic aromatic hydrocarbons(PAHs) can affect the change of telomere length by regulating the expression of telomere-related genes. Long-term exposure to PAHs can shorten the telomeres of peripheral blood leukocytes in a dose-response relationship. Telomere dysfunction is one of the important mechanisms of arsenic poisoning. The change of telomere length can be used as a biomarker of arsenic exposure. However, there are differences in the research results on the effect of arsenic exposure on telomere length, so the consistency of the effect of arsenic exposure on telomere length and the possible mechanism need to be further studied. Exposure to atmospheric fine particulate matter can attack genetic material by inducing oxidative stress and inflammatory response in the body, and then affect the telomere length of cells in vivo. Acute particulate matter exposure can increase telomere length in a short time(a few hours to a few days), and subsequent telomere shortening may be related to the inflammatory mechanism. Telomere length and telomerase activity can be used as biomarkers and play an important role in monitoring early carcinogenesis, diagnosis and prognosis assessment of cancers caused by environmental carcinogens.

Research progress on the relationship between Candida albicans and oral potentially malignant disorders / 口腔疾病防治

@#Oral potentially malignant disorders (OPMDs) refer to all epithelial lesions and conditions with an increased risk for malignant transformation, including oral leukoplakia, oral submucous fibrosis, oral lichen planus, erythroplakia, etc. Additionaly, oral infection of Candida albicans is considered to be closely related to the development of OPMDs. It was demonstrated in previous studies that the detection rate of Candida albicans was higher in the oral mucosa with OPMDs; in addition, Candida albicans showed high virulence by adhering to and destroying the epithelium. Moreover, Candida albicans was able to induce the immune response and cause chronic inflammation in the epithelium, producing carcinogenic products such as acetaldehyde. The factors mentioned above play a key role in the occurrence and development of OPMDs. Furthermore, the oral mucosa is highly susceptible to Candida albicans. The present review provides an introduction to the relationship between Candida albicans and OPMDs.

Estimates of the Prevalence, Intensity and the Number of Workers Exposed to Cigarette Smoking across Occupations and Industries in Korea

BACKGROUND: Tobacco smoking affects the incidence of various illnesses such as lung cancer, respiratory diseases, and cardiovascular diseases. In an effort to prevent smoking-related cancers, we aimed to estimate the smoking prevalence, intensity, and number of workers exposed to smoking, which would be specific to the occupational and industrial circumstances in Korea. METHODS: We used the Korean Working Condition Survey (KWCS) and Korea's Census data. Smoking prevalence and intensity were estimated using the KWCS data. The number of smokers was estimated by multiplying smoking prevalence with the number of workers in the occupation or industry. Smoking prevalence, intensity, and number of smokers were estimated for major, sub-major, and minor groups of occupation and industry. RESULTS: Of the total labor force in 2010, 52.66% of men and 5.24% of women workers were estimated to be current smokers. Men workers smoked 15.42 cigarettes/day, and women workers 11.29 cigarettes/day. In terms of occupation, “craft and related trades workers” demonstrated the highest smoking prevalence (52.24%). “Managers” smoked the highest number of cigarettes (16.63 cigarettes/day) and “equipment, machine operating, and assembling workers” comprised the largest number of estimated smokers (1,368,726 workers). In terms of industry, “mining and quarrying” had the highest smoking prevalence (69.27%). Those in “construction” smoked the highest number of cigarettes (17.16 cigarettes/day) and those in “manufacturing” comprised the largest number of estimated smokers (1,629,893 workers). CONCLUSION: Our results may help in setting priorities for smoking prevention-related activities. In addition, these results can be used for epidemiological studies controlling for the effect of smoking by occupation or industry.

Regulation of toxic contents of smokeless tobacco products

Effective regulation of contents of tobacco products is one of the primary milestones to reduce negative health effects associated with the use of smokeless tobacco (SLT) products. As per the available sources, testing of some SLT products has been done on ad hoc basis, but there is a lack of comprehensive and periodic analysis of these products. In addition, the available results indicate huge variations among the levels of pH, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, N-nitrosonornicotine, benzo[a]pyrene, heavy metals and nicotine within different products as well as within different brands of the same product. This review was aimed to throw light on the variations and gaps in testing of SLT products and emphasize the need for strong policy regulation for monitoring the chemical constituents of these products.

Carcinogens that induce the A:T > T:A nucleotide substitutions in the genome / 医学前沿

Recently, Ng et al. reported that the A:T > T:A substitutions, proposed to be a signature of aristolochic acid (AA) exposure, were detected in 76/98 (78%) of patients with hepatocellular carcinoma (HCC) from the Taiwan Province of China, and 47% to 1.7% of HCCs from the Chinese mainland and other countries harbored the nucleotide changes. However, other carcinogens, e.g., tobacco carcinogens 4-aminobiphenyl and 1,3-butadiene, air toxic vinyl chloride and its reactive metabolites chloroethylene oxide, melphalan and chlorambucil, also cause this signature in the genome. Since tobacco smoke is a worldwide public health threat and vinyl chloride distributes globally and is an air pollutant in Taiwan Province, the estimation of the patients' exposure history is the key to determine the "culprit" of the A:T > T:A mutations. Apparently, without estimation of the patients' exposure history, the conclusion of Ng et al. is unpersuasive and misleading.

Priority Setting for Occupational Cancer Prevention

BACKGROUND: Selecting priority occupational carcinogens is important for cancer prevention efforts; however, standardized selection methods are not available. The objective of this paper was to describe the methods used by CAREX Canada in 2015 to establish priorities for preventing occupational cancer, with a focus on exposure estimation and descriptive profiles. METHODS: Four criteria were used in an expert assessment process to guide carcinogen prioritization: (1) the likelihood of presence and/or use in Canadian workplaces; (2) toxicity of the substance (strength of evidence for carcinogenicity and other health effects); (3) feasibility of producing a carcinogen profile and/or an occupational estimate; and (4) special interest from the public/scientific community. Carcinogens were ranked as high, medium or low priority based on specific conditions regarding these criteria, and stakeholder input was incorporated. Priorities were set separately for the creation of new carcinogen profiles and for new occupational exposure estimates. RESULTS: Overall, 246 agents were reviewed for inclusion in the occupational priorities list. For carcinogen profile generation, 103 were prioritized (11 high, 33 medium, and 59 low priority), and 36 carcinogens were deemed priorities for occupational exposure estimation (13 high, 17 medium, and 6 low priority). CONCLUSION: Prioritizing and ranking occupational carcinogens is required for a variety of purposes, including research, resource allocation at different jurisdictional levels, calculations of occupational cancer burden, and planning of CAREX-type projects in different countries. This paper outlines how this process was achieved in Canada; this may provide a model for other countries and jurisdictions as a part of occupational cancer prevention efforts.

Epigenetic changes in cytochrome P450 and indirect carcinogen carcinogenesis:a review / 中国药理学与毒理学杂志

Cytochrome P450(CYP450),one of the most important enzymes in the human body,medi?ates the activation and toxicity of indirect poisons as well as indirect carcinogens. CYP450 is a super?family mainly composed of CYP1A, CYP1B, CYP2A, CYP2B, CYP2C, CYP2E, CYP2W, CYP3A and their activities are widely modulated by epigenetic manners, such as DNA methylation, histone modifi?cation and microRNA interference.Indirect carcinogens including benzo(a)pyrene,2,3,7,8-tetrachlorod?ibenzo-p-dioxin,diethylstilbestrol,aflatoxin B1 and cyclophosphamide,can change epigenetic modifica?tions, such as specific changes in DNA methylation, histone acetylation, methylation or ubiquitination, and up-or down-regulation of microRNA expression,which affect the function of the major subtypes of CYP450 and their role in indirect carcinogen activation.

Research progress in animal models of cholangiocarcinoma / 上海交通大学学报（医学版）

Cholangiocarcinoma (CCA) is a malignant neoplasm derived from cholangiocytes. The incidence of CCA is only lower than that of hepatocellular carcinoma and ranked the second in liver malignant cancers. The prognosis of CCA patients is poor and most patients will die within a few months after diagnosis. CCA is related to various risk factors, including primary sclerosing cholangitis, cirrhosis, certain chemical agents and liver fluke. Establishment of proper animal models of CCA can not only be helpful for understanding the mechanisms of incidence and development, but also lay a solid foundation for developing novel treatment strategies. Common animal models of CCA include carcinogen-induced models, implantation models, operation models, and genetically engineered models.

Estimates of the Number of Workers Exposed to Diesel Engine Exhaust in South Korea from 1993 to 2013

BACKGROUND: The aim of this study was to estimate the number of workers exposed to diesel engine exhaust (DEE) by industry and year in the Republic of Korea. METHOD: The estimates of workers potentially exposed to DEE in the Republic of Korea were calculated by industry on the basis of the carcinogen exposure (CAREX) surveillance system. The data on the labor force employed in DEE exposure industries were obtained from the Census on Establishments conducted by the Korea National Statistical Office from 1993 to 2013. The mean values of prevalence rates adopted by EU15 countries were used as the primary exposure prevalence rates. We also investigated the exposure prevalence rates and exposure characteristics of DEE in 359 workplaces representing 11 industries. RESULTS: The total number of workers exposed to DEE were estimated as 270,014 in 1993 and 417,034 in 2013 (2.2% of the total labor force). As of 2013, the industry categorized as “Land transport” showed the highest number of workers exposed to DEE with 174,359, followed by “Personal and household services” with 70,298, “Construction” with 45,555, “Wholesale and retail trade and restaurants and hotels” with 44,005, and “Sanitation and similar services” with 12,584. These five industries, with more than 10,000 workers exposed to DEE, accounted for 83% of the total DEE-exposed workers. Comparing primary prevalence rates used for preliminary estimation among 49 industries, “Metal ore mining” had the highest rate at 52.6%, followed by “Other mining” with 50.0%, and “Land transport” with 23.6%. CONCLUSION: The DEE prevalence rates we surveyed (1.3–19.8%) were higher than the primary prevalence rates. The most common emission sources of DEE were diesel engine vehicles such as forklifts, trucks, and vans. Our estimated numbers of workers exposed to DEE can be used to identify industries with workers requiring protection from potential exposure to DEE in the Republic of Korea.

Urinary Bladder Cancer with Focus on Occupational Dye Workers.

Benzidine based azo dyes are proven carcinogens, mutagens and have been linked to bladder cancer of human beings and laboratory animals. The textile and dyestuff manufacturing industry are the two major sources for releasing of azo dyes. Various research groups have started work on genotoxic effect of textile dyes in occupational workers of textile dye industry. Bladder cancer is the most common form of cancer in dye industries. Most of people between age 50 and 70 group of are diagnosed with bladder cancer. Men are more likely than the women to develop bladder cancer. Bladder cancer is a disease in which abnormal cells multiply without control in the bladder. The most common type of bladder cancer begins in cells lining the inside of the bladder and is called transitional cell carcinoma. Tumor markers are substances that can be found in the body when cancer is present. They are most often found in the blood or urine. The review deals about the impacts of the industry dyes on human health.

A review on harmful effects of pan masala.

Pan masala (PM) is a mixture of areca nut with slaked lime, catechu and other flavoring agents. It is widely available and used by all the sections of the Indian society. It is genotoxic as it increases sister chromatin exchange and chromatin aberrations. Among humans, it is a leading cause of oral submucous fibrosis that often progresses to oral cancer. Among experimental animals, it leads to neoplastic lesions in lung, liver and stomach. It is hepatotoxic leading to increased level of enzymes, deranged carbohydrate and lipid metabolism. It is harmful to kidneys and testes leading to increased creatinine and sperm deformities respectively. PM is a very harmful substance affecting almost all organ systems, and there is immediate need for a national policy on complete ban on the production, storage, sale and marketing of PM.

Estimation of radiogenic cancer risk coefficients of stomach cancer in Chinese population / 中华放射医学与防护杂志

Objective To estimate the excess relative risk coefficients of stomach cancer for Chinese population attributable to ionizing radiation.Methods The excess relative risk and excess absolute risk coefficients of stomach cancer were estimated based on Life Span Study by using risk models developed by BEIR Ⅶ committee (Biological Effect of Ionizing Radiation).Guided by transportation methods from Life Span Study to Americans,we determined that transportation method for Chinese population includes both multiplicative and additive models with a weight of 0.7 and 0.3 respectively,on an arithmetic scale.Besides,curve fitting was used to obtain sex-age-specific stomach cancer baseline incidence based on Chinese cancer annual report.Then,Chinese excess relative risk coefficients of stomach cancer were obtained by substituting excess relative risk,excess absolute risk of Life Span Study and Chinese baseline incidence rate into risk transportation model.Results Excess relative risk coefficients of stomach cancer for Chinese population are 0.26/Sv for male and 0.64/Sv for female,whose exposure age is 30 years old and cancer age is 60 years old.Coefficients increase with decreased exposure age and cancer age.Conclusions Excess relative risk coefficients of stomach cancer for Chinese population are by larger higher than that of Life Span Study,and their sex-age tendency are similar.

Azadirachta indica mitigates DMBA-induced hepatotoxicity: A biochemical and radiometric study.

The hepatoprotective potential of aqueous Azadirachta indica leaf extract (AAILE) was assessed against DMBA-induced hepatotoxicity. DMBA  (7,12-dimethylbenz[a] anthracene) treatment (40 mg/kg body weight, ip) to male Balb/c mice resulted in the derailment of liver function as revealed by extremely slow clearance of 99mTc-mebrofenin from liver, elevated levels of alkaline phosphatase (ALP) and alanine transaminase (ALT), compared to control group. In addition, elevated micronuclei score and high apoptotic index indicated hepatogenotoxicity in DMBA-treated mice. DMBA treatment also upregulated cytochrome P450 (CYP), cytochrome b5 (Cyt b5) and decreased glutathione-S-transferase activity in hepatic tissue, compared to control group. Enhanced lipid peroxidation (LPO) levels along with decreased reduced glutathione (GSH) level were also observed in DMBA group, compared to control group. AAILE co-treatment (200 mg/kg body weight, po, thrice a week) for 8 weeks followed by DMBA injection showed significant improvement in hepatic status, as revealed by normalization of 99mTc-mebrofenin clearance rate, decreased ALP and ALT levels, reduced genotoxicity in terms of micronuclei score and apoptotic index. Levels of LPO were significantly decreased along with increased hepatic GST and GSH levels in AAILE + DMBA group, compared to DMBA group. However, no significant change was observed in hepatic CYP and Cyt b5 levels, compared to DMBA group. The results indicated that AAILE effectively ameliorated DMBA-induced hepatotoxicity.

Increase of diesel car raises health risk in spite of recent development in engine technology

Diesel exhaust particles (DEP) contain elemental carbon, organic compounds including Polyaromatic hydrocarbons (PAHs), metals, and other trace compounds. Diesel exhaust is complex mixture of thousands of chemicals. Over forty air contaminants are recognized as toxicants, such as carcinogens. Most diesel exhaust particles have aerodynamic diameters falling within a range of 0.1 to 0.25 microm. DEP was classified as a definite human carcinogen (group 1) by the International Agency for Research on Cancer at 2012 based on recently sufficient epidemiological evidence for lung cancer. Significant decreases in DEP and other diesel exhaust constituents will not be evident immediately, and outworn diesel car having longer mileage still threatens health of people in spite of recent remarkable development in diesel engine technology. Policy change in South Korea, such as introduction of diesel taxi, may raise health risk of air pollution in metropolitan area with these limitations of diesel engine. To protect people against DEP in South Korea, progressive strategies are needed, including disallowance of diesel taxi, more strict regulation of diesel engine emission, obligatory diesel particulate filter attachment in outworn diesel car, and close monitoring about health effects of DEP.

Molecular Markers in Thyroid Cancer / Marcadores moleculares en el cáncer de tiroides

Advances in thyroid molecular biology studies are providing not only insight into thyroid development of diseases but may offer diagnostic and therapeutic potential in thyroid cancer. Objective: To describe the molecular aspects of thyroid cancer reported in international scientific literature, as well as their indications and epidemiological impact, through a descriptive bibliographical review. Method: Articles were searched in the EMBASE, and PubMed/Medline databases. Inclusion criteria were: publication between 1985 and 2012; keywords "molecular" AND "markers" AND "thyroid" AND "cancer". With these documents in hands, an analytical reading was done and the papers organized by themes. Results: Out of the 609 documents found, 85 were selected to present information on several molecular, epidemiological, and practices-related aspects of thyroid cancer. Articles were assessed and classified according to predetermined categories, especially number and types of markers analyzed. Among the most relevant information, we can mention the indications for use of molecular markers in thyroid cancer, which are found in more than 70 % of papillary and follicular thyroid carcinomas. The use of these markers will probably improve the diagnosis of malignancy in thyroid nodules and it may also allow individualization of surgical therapy and postoperative management. Conclusion: This study shows the importance of knowledge of molecular aspects of thyroid cancer, which allows identification of the correlation between specific mutations and phenotypic characteristics of thyroid cancer, which is essential for its prognosis.

Los avances en biología molecular de la tiroides no solo proporcionan una visión sobre el desarrollo de la enfermedad de la tiroides, sino que además pueden ofrecer posibilidades diagnósticas y terapéuticas para el cáncer de tiroides. Objetivo: Describir los aspectos moleculares del cáncer de tiroides presentados en la literatura científica internacional, así como sus indicaciones y el impacto epidemiológico, a través de una revisión bibliográfica descriptiva. Método: Se buscaron artículos en las bases de datos EMBASE y PubMed / Medline. Los criterios de inclusión fueron: publicación entre 1985 y 2012; palabras clave "molecular" + "marcadores" + "tiroides" + "cáncer". Con estos documentos en mano, se realizó una lectura analítica y se organizaron los trabajos por temas. Resultados: De los 609 artículos encontrados, 85 fueron seleccionados para presentar información sobre los aspectos moleculares, epidemiológicos y de prácticas de cáncer de tiroides. Los artículos fueron evaluados y clasificados de acuerdo con categorías predefinidas, especialmente el número y los tipos de marcadores analizados. Entre la información más relevante, cabe mencionar las indicaciones de uso de los marcadores moleculares en el cáncer de tiroides, que se encuentran en más del 70 % de los carcinomas papilar y folicular de la tiroides. El empleo de estos marcadores probablemente mejore el diagnóstico de malignidad en los nódulos tiroideos, y quizás permita individualizar el tratamiento quirúrgico y el seguimiento posoperatorio. Conclusión: Este estudio muestra la importancia del conocimiento de aspectos moleculares del cáncer de tiroides, que permite la identificación de la correlación entre las mutaciones específicas y las características fenotípicas del cáncer de tiroides, esencial para su pronóstico.

Necessity for a National Carcinogen List in Korea, Based on International Harmonization

Cancer has been the leading cause of death in Korea for the last 30 years. Cancer patients' 5-year survival rate between 2005 and 2009 was 62.0%, representing a highly advanced standard of care, as much as developed countries in the EU and the US. The Korean government formulated its first 10-year plan for cancer control in 1996 and has been carrying out a second 10-year plan for cancer control since 2006. But despite the Korean government's efforts, the cancer burden in Korea continues to increase. Many separate laws have gone into effect concerning the management of carcinogen exposure. However, there are no integrated regulatory laws or management systems against carcinogen exposure in Korea. Dead zones remain where carcinogen exposure cannot be controlled properly in Korea. In this paper, we suggest the need to establish a national carcinogen list based on international harmonization as a prerequisite for a paradigm shift in cancer control policy from treatment to primary prevention.

Effects of cow ghee (clarified butter oil) & soybean oil on carcinogen-metabolizing enzymes in rats.

Background & objectives: Our previous study showed that cow ghee relative to soybean oil had a protective effect against carcinogen induced mammary cancer in rats. The objective of this study was to elucidate its biochemical mechanism. Methods: Two groups of 21 day old rats (20 each) were fed for 44 wk diet containing cow ghee or soybean oil (10%). Five animals from each group were sacrificed at 0 day and at 5, 21 and 44 wk for analysis of phase I and phase II pathways enzymes of carcinogen metabolism. Results: Dietary cow ghee relative to soybean oil decreased the activities of cytochrome P450 (CYP) enzymes, CYP1A1, CYP1A2, CYP1B1 and CYP2B1, responsible for activation of carcinogen in liver. Carcinogen detoxification activities of uridinediphospho-glucuronosyl transferase (UDPGT) and quinone reductase (QR) in liver, and γ-glutamyltranspeptidase (GGTP) and QR in mammary tissue were significantly higher in cow ghee fed rats than in soybean oil fed rats. The hepatic GGTP activity decreased on soybean oil diet; while in cow ghee group it remained unaffected. Interpretation & conclusions: Our findings show that dietary cow ghee compared to soybean oil downregulates the enzyme activities responsible for carcinogen activation in liver and upregulates carcinogen detoxification activities in liver and mammary tissues.

Progress in models of pancreatic cancer / 国际外科学杂志

Pancreatic cancer is a highly malignant tumor. Animal models of pancreatic cancer included xenograft models, carcinogen induced models, genetically engineered models. Xenograft models are relatively reliable and feasible, but the growth pattern is different between serve immunodeficienct animals and human beings. Carcinogens induced models simulated the environmental factors to reconstruct the development of pancreatic cancer. But carcinogens could have other biological effects. Genetically engineered models could make the occurrence of pancreatic cancer at the molecular level. But it is difficult to control the transgenic product accurately. No model could meet all the needs of different experiments. It is important to choose a suitable animal model in different experiments.

Quantitative Exposure Assessment of Various Chemical Substances in a Wafer Fabrication Industry Facility

OBJECTIVES: This study was designed to evaluate exposure levels of various chemicals used in wafer fabrication product lines in the semiconductor industry where work-related leukemia has occurred. METHODS: The research focused on 9 representative wafer fabrication bays among a total of 25 bays in a semiconductor product line. We monitored the chemical substances categorized as human carcinogens with respect to leukemia as well as harmful chemicals used in the bays and substances with hematologic and reproductive toxicities to evaluate the overall health effect for semiconductor industry workers. With respect to monitoring, active and passive sampling techniques were introduced. Eight-hour long-term and 15-minute short-term sampling was conducted for the area as well as on personal samples. RESULTS: The results of the measurements for each substance showed that benzene, toluene, xylene, n-butyl acetate, 2-methoxyethanol, 2-heptanone, ethylene glycol, sulfuric acid, and phosphoric acid were non-detectable (ND) in all samples. Arsine was either "ND" or it existed only in trace form in the bay air. The maximum exposure concentration of fluorides was approximately 0.17% of the Korea occupational exposure limits, with hydrofluoric acid at about 0.2%, hydrochloric acid 0.06%, nitric acid 0.05%, isopropyl alcohol 0.4%, and phosphine at about 2%. The maximum exposure concentration of propylene glycol monomethyl ether acetate (PGMEA) was 0.0870 ppm, representing only 0.1% or less than the American Industrial Hygiene Association recommended standard (100 ppm). CONCLUSION: Benzene, a known human carcinogen for leukemia, and arsine, a hematologic toxin, were not detected in wafer fabrication sites in this study. Among reproductive toxic substances, n-butyl acetate was not detected, but fluorides and PGMEA existed in small amounts in the air. This investigation was focused on the air-borne chemical concentrations only in regular working conditions. Unconditional exposures during spills and/or maintenance tasks and by-product chemicals were not included. Supplementary studies might be required.