Socioeconomic status, health behavior, and leukocyte telomere length in the National Health and Nutrition Examination Survey, 1999-2002.

The purpose of this study was to examine the association between socioeconomic status (SES) and leukocyte telomere length (LTL) - a marker of cell aging that has been linked to stressful life circumstances - in a nationally representative, socioeconomically and ethnically diverse sample of US adults aged 20-84. Using data from the National Health and Nutrition Examination Survey (NHANES), 1999-2002, we found that respondents who completed less than a high school education had significantly shorter telomeres than those who graduated from college. Income was not associated with LTL. African-Americans had significantly longer telomeres than whites, but there were no significant racial/ethnic differences in the association between education and telomere length. Finally, we found that the association between education and LTL was partially mediated by smoking and body mass index but not by drinking or sedentary behavior.

Employment and work schedule are related to telomere length in women.

OBJECTIVES: To examine the association of employment and work schedule with shorter DNA telomeres, a marker of cellular ageing and disease risk factor, and consider whether differences were related to health, behaviours and sociodemographic factors, or varied by stress levels or menopausal status. METHODS: This cross-sectional analysis of 608 women aged 35-74 in the Sister Study examined determinants of relative telomere length (rTL) measured by quantitative PCR in leucocyte DNA. Age-adjusted regression models estimated base pair (bp) rTL differences for current and lifetime schedule characteristics (ie, part-time, full-time or overtime hours; multiple jobs; irregular hours; shiftwork; work at night). Covariates included race, smoking, perceived stress, sleep, physical activity, health and menopausal status, education, marital status, live births, children under 18, measured body mass index and urinary stress hormones. RESULTS: Compared with non-employed women with moderate or substantial past work histories (n=190), those currently working full-time (n=247; median 40 h/week) had a shorter rTL, an age-adjusted difference of -329 bp (95% CI -110 to -548). Longer-duration full-time work was also associated with shorter rTL (age-adjusted difference of -472 bp, 95% CI -786 to -158 for 20+ vs 1-5 years). Findings were not explained by health and demographic covariates. However, rTL differences for working at least full-time were greater in women with higher stress and epinephrine levels. CONCLUSIONS: Current and long-term full-time work were associated with shorter rTL, with differences of similar magnitude to smoking and history of heart disease or diabetes. Longitudinal data with specific stress measures are needed to further evaluate the impact of work schedule on rTL.

Leukocytes segmentation using Markov random fields.

The segmentation of leukocytes and their components plays an important role in the extraction of geometric, texture, and morphological characteristics used to diagnose different diseases. This paper presents a novel method to segment leukocytes and their respective nucleus and cytoplasm from microscopic bone marrow leukemia cell images. Our method uses color and texture contextual information of image pixels to extract cellular elements from images, which show heterogeneous color and texture staining and high-cell population. The CIEL ( ∗ ) a ( ∗ ) b ( ∗ ) color space is used to extract color features, whereas a 2D Wold Decomposition model is applied to extract structural and stochastic texture features. The color and texture contextual information is incorporated into an unsupervised binary Markov Random Field segmentation model. Experimental results show the performance of the proposed method on both synthetic and real leukemia cell images. An average accuracy of 95% was achieved in the segmentation of real cell images by comparing those results with manually segmented cell images.

Rater agreement and utility of the mutagen-induced chromosome damage assay.

Chromosomal damage in peripheral blood lymphocytes induced by short-term in vitro exposure to the cytotoxic antibiotic bleomycin was first described in 1983 and proposed as a phenotypic assay for chromosome instability. This assay was subsequently described as potentially useful in assessing an individual's risk to environmental carcinogens in 1989. Since 1995 numerous published studies have used this assay to assess risk for cancer in the aerodigestive tract, particularly lung cancer, in various ethnic populations. Odds ratios up to 8.5 have been reported for individuals deemed "mutagen sensitive" (defined as > or = 1 chromatid break per metaphase averaged in 50 metaphases analyzed). While this phenotypic assay is appealing for lung cancer risk assessment it has not been reproduced by other investigators. Because of our interest in lung cancer biology, epidemiology, and genetics, we sought to independently assess the rater agreement of this assay. We found that 1) the assay is laborious to conduct (8 hours of labor) and relatively expensive (> $100), yet reducing the number of metaphases from 50 to 20 produced a reliable, less expensive, and less laborious test; and 2) the rater agreement of individual metaphase readings is poor, but agreement for a summary measure is high.

[Assessment of the membrane properties of blood leukocytes in patients with purulent septic complications]. / Otsenka membrannykh svoistv leikotsitov krovi u bolnykh s gnoino-septicheskimi oslozhneniiami.

Osmotic resistance of leukocytic membranes was studied in 36 patients with purulent-septic complications and in 43 donors. As a damaging medium, 0.45% solution of sodium chloride was used. The cells were incubated in it for 30 min at a temperature of 37 degrees C. It was established that in purulent-septic complications, the structural-functional properties of leukocytes changed. This resulted in decreased resistance of their membranes.