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1.
Humans are environmentally and occupationally exposed to polycyclic aromatic hydrocarbons (PAH). PAH's are a class of tumorigenic compounds which act through metabolic transformation to chemically reactive forms, epoxides, which covalently bind to DNA forming DNA adducts. To evaluate the genotoxic effects of PAH's, air and urine samples were analyzed for PAH. Blood samples were analyzed for benzo(a)pyrene-diol-epoxide-DNA (BPDE-DNA) adducts. New methods for analyzing DNA adducts in lymphocytes have been used to study the genotoxic effects of human exposure to carcinogens. BPDE-DNA adducts in lymphocytes have been used as internal dosimeters of exposure to PAH's and several studies have been conducted. We measured BPDE-DNA adducts in aluminium plant workers with immuno-assay and physico-chemical methods. PAH-DNA adducts were detectable to a lesser extent in subjects working in an aluminium plant compared to subjects working in a coke oven plant. 相似文献
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E.M. Smith Ph.D. S.R. Johnson M.D. E.J. Figuerres M.S. M. Mendoza M.S. D. Fedderson B.S. T.H. Haugen M.D. L.P. Turek M.D. 《Gynecologic oncology》1997,65(3):441-446
Postmenopausal women enrolled in the Iowa portion of the postmenopausal estrogen/progestin interventions randomized clinical trial (n= 105) during 1989–1991 were studied for (i) the prevalence of human papillomavirus (HPV) in this older age population (ages 45–64), and (ii) the association between hormone replacement therapies (HRTs) and changes in detection of HPV over a 2-year time period. HPV is causative in most cervical and some other genital cancers and in the presence of steroid hormones has been shown to increase neoplastic transformation by HPVin vitro.Using PCR to detect HPV DNA, the overall frequency of the virus regardless of time period was 50.3% (n= 53) with a baseline (BL) frequency of 38.1% and the second year follow-up (FU) of 22.9%. The oncogenic types HPV-16 (75.5%) and HPV-31 (20.8%) were the most commonly reported. All those with persistently detected infection (10.5%), defined as HPV+ at both BL and FU, were identified with HPV-16 or -18. Between these two time periods there were no significant differences in HPV frequency between the placebo and combined HRT groups (BL−/FU+, 21% vs 18%; BL+/FU−, 71% vs 80%). While the study is based on a small sample, the findings suggest that short-term use of HRTs is not associated with an increased risk of HPV detection, but assessment of effects from long-term use is needed. The data also indicate that the frequency of HPV found in older women is higher than previously suspected but that short-term changes in HPV detected in this age group are unrelated to the development of precancerous cervical lesions. 相似文献
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Androgen receptor YAC transgenic mice carrying CAG 45 alleles show trinucleotide repeat instability 总被引:1,自引:15,他引:1
La Spada AR; Peterson KR; Meadows SA; McClain ME; Jeng G; Chmelar RS; Haugen HA; Chen K; Singer MJ; Moore D; Trask BJ; Fischbeck KH; Clegg CH; McKnight GS 《Human molecular genetics》1998,7(6):959-967
X-linked spinal and bulbar muscular atrophy (SBMA) is caused by a CAG
repeat expansion in the first exon of the androgen receptor (AR) gene.
Disease-associated alleles (37-66 CAGs) change in length when transmitted
from parents to offspring, with a significantly greater tendency to shift
size when inherited paternally. As transgenic mice carrying human AR cDNAs
with 45 and 66 CAG repeats do not display repeat instability, we attempted
to model trinucleotide repeat instability by generating transgenic mice
with yeast artificial chromosomes (YACs) carrying AR CAG repeat expansions
in their genomic context. Studies of independent lines of AR YAC transgenic
mice with CAG 45 alleles reveal intergenerational instability at an overall
rate of approximately 10%. We also find that the 45 CAG repeat tracts are
significantly more unstable with maternal transmission and as the
transmitting mother ages. Of all the CAG/CTG repeat transgenic mice
produced to date the AR YAC CAG 45 mice are unstable with the smallest
trinucleotide repeat mutations, suggesting that the length threshold for
repeat instability in the mouse may be lowered by including the appropriate
flanking human DNA sequences. By sequence-tagged site content analysis and
long range mapping we determined that one unstable transgenic line has
integrated an approximately 70 kb segment of the AR locus due to
fragmentation of the AR YAC. Identification of the cis - acting elements
that permit CAG tract instability and the trans -acting factors that
modulate repeat instability in the AR YAC CAG 45 mice may provide insights
into the molecular basis of trinucleotide repeat instability in humans.
相似文献
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Abstract Data on the metabolic responses to repeated endurance exercise sessions are limited. Thus, the aims of this study were to examine (1) the impact of prior exercise on metabolic responses to a subsequent exercise session and (2) the effect of different recovery periods between two daily exercise sessions on metabolic responses to the second bout of exercise. Nine male elite athletes participated in four 25-h trials: one bout of exercise (ONE), two bouts of exercise separated by 3 h of rest and one meal (SHORT), two bouts of exercise separated by 6 h of rest and two meals (LONG), and a trial with no exercise (REST). All exercise bouts consisted of 10 min cycling at 50% followed by 65 min at 75% of maximal O2 uptake. Compared to no prior exercise (ONE), a previous bout of exercise (SHORT) was followed by higher mean O2 uptake, heart rate (HR), rectal temperature (TR), excess post-exercise oxygen consumption and lower respiratory exchange ratio (R) during and after a similar exercise session 3 h later. A longer rest interval between the two exercise bouts (6 h versus 3 h) and an additional meal resulted in a decrease in O2 uptake, HR, TR and an increase in R during the second bout of exercise, but no effects on post-exercise metabolism were found. Thus, augmented metabolic stress was observed when strenuous exercise was repeated after only 3 h of recovery, but this was attenuated when a longer recovery period including an additional meal was provided between the exercise sessions. 相似文献
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Summary
Objective: This study investigated the prevalence and nature of generalized anxiety symptoms in women who were eight weeks postpartum.
Method: A community-based sample of 68 postpartum women completed an interview assessing generalized anxiety disorder and depression
and a self-report measure of worry associated with concerns relevant to postpartum women.
Results: Three women (4.4%) met DSM-IV criteria for generalized anxiety disorder, and an additional 19 women (27.9%) endorsed subsyndromal
difficulties with generalized anxiety. Approximately one third of these women endorsed symptoms of depression. In contrast,
only two woman met criteria for major depressive disorder.
Conclusion: Postpartum generalized anxiety has a higher prevalence than postpartum depression.
Received February 26, 2002; accepted November 11, 2002 Published online January 31, 2003
Acknowledgement This work was supported by a New Faculty Scholar Award and a Graduate Research Fellowship from the University of North Dakota.
The authors would like to express their appreciation to Jennifer Brendle, Peter Schmutzer, Talia Tweten, and Chad Lystad for
their assistance with this research.
Correspondence: Amy Wenzel, Ph.D., Department of Psychology, University of North Dakota, Grand Forks, ND 58202-8380, U.S.A.;
e-mail: amy_wenzel@und.nodak.edu 相似文献