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排序方式: 共有119条查询结果,搜索用时 531 毫秒
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Chromosomal aberration and sister-chromatid exchange frequencies in peripheral blood lymphocytes of a large human population sample 总被引:4,自引:0,他引:4
M A Bender R J Preston R C Leonard B E Pyatt P C Gooch M D Shelby 《Mutation research》1988,204(3):421-433
In order to assess the potential of cytogenetic determinations on peripheral blood lymphocytes as a means of monitoring human populations subject to low level occupational and environmental exposures to chemical mutagens and carcinogens, accurate baseline data are required. Accordingly, we have determined mean frequencies of chromosomal aberrations and of sister-chromatid exchanges, their variances, and the sources of this variance in a cohort of 353 healthy employees of the Brookhaven National Laboratory. A detailed protocol was adopted for blood sampling, lymphocyte culture, cytogenetic preparation and scoring in order to minimize variation from these potential sources. Scoring was divided between the Oak Ridge and the Brookhaven groups with duplicate scoring sufficient to evaluate and minimize the effect of any differences between laboratories or between individual scorers. In all, the data include 71,950 cells scored for chromosomal aberrations and 16,898 cells scored for sister-chromatid exchanges. The mean unadjusted frequency of sister-chromatid exchanges was 8.29 +/- 0.08/cell. As reported in other studies, cigarette smoking very significantly influenced sister-chromatid exchange frequencies; in our study the mean for smokers was 9.0 +/- 0.2, while that for non-smokers was 8.1 +/- 0.1/cell. The mean frequency was statistically higher in females than in males, regardless of smoking status. On the other hand, age of the subject did not significantly influence sister-chromatid exchange frequencies. Curiously, the subject's total white cell count did influence sister-chromatid exchange frequency. No other source of variation was found. The frequencies of chromosomal aberrations of all types were determined. The frequency of the most common unequivocal chromatid type, the chromatid deletion, was 0.81 +/- 0.05%, that of the most common unequivocal chromosome type, the dicentric, was 0.16 +/- 0.02%. No statistically significant influence was found of age or sex, nor of any other parameter tested, on the frequency of any chromosomal aberration type, with the single exception of long acentric fragments, often "supernumerary", believed to represent X chromosomes precociously separated at the centromere. Such fragments were significantly more frequent in samples from females than those from males, and showed a significant positive regression on age. 相似文献
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Erratum: Wunderlich RE, Simons EL, Jungers WL. 1996. New Pedal Remains of Megaladapis and Their Functional Significance. Am J Phys Anthropol 100:115–139. 相似文献
64.
C. MIQUEL E. BELLEMAIN C. POILLOT J. BESSIRE A. DURAND P. TABERLET 《Molecular ecology resources》2006,6(4):985-988
In noninvasive studies, the intersample variance in DNA quality and quantity is large, and produces multilocus genotypes of highly variable quality. Here we propose a standardized method for testing the reliability of the genotyping procedure when using the multiple‐tube approach. The quality indexes generated will allow reliable comparisons among samples, loci, studies, and field and/or laboratory protocols. These indexes represent a powerful tool for the quality management of noninvasive studies. 相似文献
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J. S. Lakind S. T. Holgate D. R. Ownby A. H. Mansur P. J. Helms D. Pyatt 《Biomarkers》2013,18(5):445-467
Biomarkers associated with asthma aetiology and exacerbation have been sought to shed light on this multifactorial disease. One candidate is the serum concentration of the Clara cell secretory protein (CC16, sometimes referred to as CC10 or uteroglobin). In this review, we examine serum CC16's relation to asthma aetiology and exacerbation. There is evidence that acute exposures to certain pulmonary irritants can cause a transient increase in serum CC16 levels, and limited evidence also suggests that a transient increase in serum CC16 levels can be caused by a localized pulmonary inflammation. Research also indicates that a transient increase in serum CC16 is not associated with measurable pulmonary damage or impairment of pulmonary function. The biological interpretation of chronic changes in serum CC16 is less clear. Changes in serum CC16 concentrations (either transient or chronic) are not specific to any one agent, disease state, or aetiology. This lack of specificity limits the use of serum CC16 as a biomarker of specific exposures. To date, many of the critical issues that must be understood before serum CC16 levels can have an application as a biomarker of effect or exposure have not been adequately addressed. 相似文献
66.
1. Conifer‐feeding budworms (Choristoneura) hibernate in sheltered locations on their host trees from late summer of 1 year to spring of the next. During this period, they do not feed but rely on sustenance provided in the egg. Overwinter survival is dependent on the rate of consumption of these limited reserves. 2. A process model was developed that quantifies the relationship between the rate of consumption and survival at variable temperatures and exposure times for western spruce budworm. The model supported physiological evidence that warm weather conditions early in the diapause period have a dominant influence on overwinter survival. Output compared favourably with field observations of poorer budworm survival at lower elevations where late‐summer and autumn temperatures were warmer compared to those overwintering at cooler, higher elevations. 3. Field experiments demonstrated these weather‐dependent rates of survival were modulated significantly by the degree of shelter experienced by hibernating budworms. 4. Dissection of whole trees harbouring overwintering western spruce budworms showed a significant portion of the population had travelled a considerable distance from the periphery of the tree canopy where eggs were laid to overwinter successfully on the tree bole where sheltered niches are common. 5. Thus, budworms will travel relatively long distances and risk increased mortality during this dispersal to find adequate shelter to overwinter. 相似文献
67.
代解杰 《中国实验动物学报》2005,(Z1)
[目的]评价抗黄体酮(mifepristone)联合Aromatase抑制剂(letrozole或aminoglutethimide)或iNOS抑制剂(aminoguandine)是否能有效终止恒河猴早期妊娠。[方法]将30只猴子随机分为5组(治疗组每组6只,对照组6只),并在妊娠30,31和32天进行如下处理:对照组,每只动物1ml安慰剂;A组,Mifepristone(1mg/kg,sc.);B组,Mifepristone(sc.)+Letrozole(2.5mg/只sc.);C组,Mifepristone(1mg/kg,sc.)+aminoglute-chimide(50mg/kgsc.,bid);D组,Mifepristone(1mg/kg,sc.)+aminoguanidine(150mg/kg,sc.,bid)。所有妊娠猴在妊娠29天通过超声波确认。[结果]在B、C、D组,所有的动物的妊娠都在妊娠早期被终止(6/6)。A组和对照组的妊娠终止率分别为3/6和2/6。同时,联合用药能够有效排空子宫腔和减少出血。[结论]该处理能有效地终止恒河猴早期妊娠。联合用药比用于女人的妊娠治疗更有效,并减少了流血时间,或许可以代替目前的终止妊娠的医疗方法。 相似文献
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Juhas M Power PM Harding RM Ferguson DJ Dimopoulou ID Elamin AR Mohd-Zain Z Hood DW Adegbola R Erwin A Smith A Munson RS Harrison A Mansfield L Bentley S Crook DW 《Genome biology》2007,8(11):R237-14