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Leukemia Risk (leukemia + risk)
Selected AbstractsDermal benzene and trichloroethylene induce aneuploidy in immature hematopoietic subpopulations in vivoENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 3 2001Cynthia R. Giver Abstract Accumulation of genetic damage in long-lived cell populations with proliferative capacity is implicated in tumorigenesis. Hematopoietic stem cells (hsc) maintain lifetime hematopoiesis, and recent studies demonstrate that hsc in leukemic patients are cytogenetically aberrant. We postulated that exposure to agents associated with increased leukemia risk would induce genomic changes in cells in the hsc compartment. Aneusomy involving chromosomes 2 and 11 in sorted hsc (Lin,c-kit+Sca-1+) and maturing lymphoid and myeloid cells from mice that received topical doses of benzene (bz) or trichloroethylene (TCE) was quantified using fluorescence in situ hybridization. Six days after bz or TCE exposure, aneuploid cells in the hsc compartment increase four- to eightfold in a dose- and schedule-independent manner. Aneuploid lymphoid and myeloid cells from bz- and TCE-treated mice approximate controls, except after repeated benzene exposures. Aneuploid cells are more frequent in the hsc compartment than in mature hematopoietic subpopulations. Hematotoxicity was also quantified in bz- and TCE-exposed hematopoietic subpopulations using two colony-forming assays: CFU-GM (colony-forming units/granulocyte-macrophage progenitors) and CAFC (cobblestone area,forming cells). Data indicate that bz is transiently cytotoxic (,1 week) to hsc subpopulations, and induces more persistent toxicity (>2 weeks) in maturing, committed progenitor subpopulations. TCE is not hematotoxic at the doses applied. In conclusion, we provide direct evidence for induction of aneuploidy in cells in the hsc compartment by topical exposure to bz and TCE. Disruption of genomic integrity and/or toxicity in hsc subpopulations may be one step in leukemic progression. Environ. Mol. Mutagen. 37:185,194, 2001. © 2001 Wiley-Liss, Inc. [source] Methylphenidate use in children and risk of cancer at 18 sites: results of surveillance analyses,PHARMACOEPIDEMIOLOGY AND DRUG SAFETY, Issue 12 2007Nina Oestreicher PhD Abstract Purpose A recent report linked methylphenidate (MPH) use in children to cytologic abnormalities in plasma lymphocytes, a possible cancer biomarker. The purpose of this study was to investigate the association of MPH use and childhood cancer risk. Methods Using automated pharmacy databases and the SEER-affiliated cancer registry of the Kaiser Permanente Medical Care Program (KPMCP), we compared cancer rates at 18 sites among 35 400 MPH users who received it before age 20 to rates among KPMCP membership (age, sex, and calendar year standardized). Medical records of MPH exposed cancer cases were reviewed to identify the presence of established risk factors. Results There were 23 cancers among MPH users, versus 20.4 expected (standardized morbidity ratio, SMR,=,1.13, 95% confidence interval (0.72, 1.70)). Given the small number of cancers, site-specific SMR estimates were imprecise. Only one SMR was statistically significant at the p,<,0.05 level, which given the number of comparisons is consistent with the absence of a true association at any site. MPH use was associated with increased risk of lymphocytic leukemia (SMR,=,2.64 (1.14, 5.20)), based on eight observed cases). The medical records of these exposed cases did not reveal any lymphocytic leukemia risk factors (prior cancer, radiotherapy or chemotherapy, or Down syndrome). Conclusions Our results are consistent with no moderate or strong association between MPH use and cancer risk in children, although our ability to examine dose and duration of use or risk at specific sites was limited by small numbers. Further study of MPH use and lymphocytic leukemia risk is needed to determine whether our results are due to chance alone. Copyright © 2007 John Wiley & Sons, Ltd. [source] Leukemia and exposure to ionizing radiation among German uranium minersAMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 4 2006Matthias Möhner PhD Abstract Background It is well known that uranium miners are at an increased risk of lung cancer. Whether they also have an increased risk for other cancer sites remains under discussion. The aim of this study was to examine the leukemia risk among miners. Methods An individually matched case-control study of former uranium miners in East Germany was conducted with 377 cases and 980 controls. Results Using conditional logistic regression models, a dose,response relationship between leukemia risk and radon progeny could not be confirmed. Yet, a significantly elevated risk is seen in the category ,400 mSv when combining ,-radiation and long-lived radionuclides. Conclusions The results suggest that an elevated risk for leukemia is restricted to employees with a very long occupational career in underground uranium mining or uranium processing. Moreover, the study does not support the hypothesis of an association between exposure to short-lived radon progeny and leukemia risk. Am. J. Ind. Med. 49:238,248, 2006. © 2006 Wiley-Liss, Inc. [source] Occupation and leukemia: A population-based case,control study in Iowa and Minnesota,AMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 1 2001A. Blair PhD Abstract Background Studies have suggested that risk of leukemia may be associated with occupational or industrial exposures and risk may vary by the histological type of the disease. Methods A population-based case,control study was conducted in Iowa and Minnesota to evaluate the association between various occupations, industries, and occupational exposures and leukemia risk. A total of 513 cases and 1,087 controls was included in the study. A lifetime occupational history and other risk factor information were collected through in-person interviews, and a job-exposure matrix was used to assess possible risks associated with specific exposures. Results A significantly increased risk of leukemia was observed among agricultural service industries and among nursing and healthcare workers. Janitors, cleaners, and light truck drivers also experienced increased risk. Those employed in plumbing, heating and air conditioning industries, and sales of nondurable goods (such as paints and varnishes) had an increased risk. Printers, painters, and workers in the food and metal industries had a nonsignificantly increased risk of leukemia. Analyses by specific exposures and histology of leukemia showed that risk of leukemia associated with occupational or industrial exposures may vary by histological type of the disease. Conclusions An increased risk of leukemia among workers employed in agricultural industries, nursing and healthcare workers, and in a few occupations with possible exposure to solvents is consistent with earlier studies. Associations of risk with occupations not observed previously deserve further assessment. Am. J. Ind. Med. 40:3,14, 2001. Published 2001 Wiley-Liss, Inc. [source] ELF-magnetic flux densities measured in a city environment in summer and winterBIOELECTROMAGNETICS, Issue 1 2008Aksel Straume Abstract Epidemiological studies have indicated a connection between extremely low frequency magnetic flux densities above 0.4,µT (time weighted average) and childhood leukemia risks. This conclusion is based mainly on indoor exposure measurements. We therefore regarded it important to map outdoor magnetic flux densities in public areas in Trondheim, Norway. Because of seasonal power consumption variations, the fields were measured during both summer and winter. Magnetic flux density was mapped 1.0 m above the ground along 17 km of pavements in downtown Trondheim. The spectrum was measured at some spots and the magnetic flux density emanated mainly from the power frequency of 50 Hz. In summer less than 4% of the streets showed values exceeding 0.4,µT, increasing to 29% and 34% on cold and on snowy winter days, respectively. The average levels were 0.13,µT (summer), 0.85,µT (winter, cold), and 0.90,µT (winter, snow), with the highest recorded value of 37,µT. High spot measurements were usually encountered above underground transformer substations. In winter electric heating of pavements also gave rise to relatively high flux densities. There was no indication that the ICNIRP basic restriction was exceeded. It would be of interest to map the flux density situation in other cities and towns with a cold climate. Bioelectromagnetics 29:20,28, 2008. © 2007 Wiley-Liss, Inc. [source] | |||||||||||||