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Biomedical subjects

N Craft

Publications and source records attributed to N Craft.

At least 19 recordsLinked to original sources
PubMed2001

Serum carotenoids and radiographic knee osteoarthritis: the Johnston County Osteoarthritis Project.

OBJECTIVE: Antioxidant intake has been associated with less progression of radiographic knee osteoarthritis (OA), but studies of carotenoid biomarkers and OA have not been done. We examined associations between serum concentrations of nine naturally occurring carotenoids and radiographic knee OA. DESIGN: The study design was matched case-control. Sera were analysed by high-performance liquid chromatography for nine carotenoids: lutein, zeaxanthin, alpha- and beta-cryptoxanthin, trans- and cis-lycopene, alpha-carotene, and trans- and cis-beta-carotene. Conditional logistic regression was used to estimate the association between tertiles of each carotenoid and radiographic knee OA, independent of body mass index, education, serum cholesterol, and the other carotenoids. SETTING: Johnston County, North Carolina, United States of America. SUBJECTS: Two-hundred cases with radiographic knee OA (Kellgren-Lawrence grades > or = 2) and 200 controls (Kellgren-Lawrence grade = 0) were randomly selected from the Johnston County Osteoarthritis Project, and were matched on age, gender and race. RESULTS: Participants with serum levels of lutein or beta-cryptoxanthin in the highest tertile were approximately 70% less likely to have knee OA than controls (odds ratio (OR) [95% confidence interval (CI)] = 0.28 [0.11, 0.73] and 0.36 [0.14, 0.95], respectively). Those in the highest tertile of trans-beta-carotene (OR = 6.40 [1.86, 22.1]) and zeaxanthin (OR = 3.06 [1.19, 7.85]) were more likely to have knee OA. CONCLUSIONS: While certain carotenoids may protect against knee OA, others may increase the odds of knee OA. Further study of carotenoids and knee OA are warranted before clinical recommendations about these substances and knee OA can be made.

Antioxidants↗
PubMed2001

Navy Asbestos Medical Surveillance Program, 1995-1999: demographic characteristics and smoking status.

A descriptive study of the Navy Asbestos Medical Surveillance Program is presented from data provided by the Navy Environmental Health Center in Norfolk, Virginia, with an emphasis on demographic characteristics and smoking. Analysis of 79,598 physical examinations for the period 1995 to 1999 revealed that Navy and Marine Corps civil service employees constituted 90% and Navy active duty personnel constituted 9%. Most personnel reported "no current exposure, have prior exposure" to asbestos (Navy active duty, 77%; civil service employees, 61%). Current smoking rates per year decreased for Navy active duty (from 34.6% to 28.7%) and civil service workers (from 26.0% to 21.6%), both reductions being significant for trend. Logistic regression for current smoking showed higher rates for Navy active duty and those with "direct" asbestos exposure, whereas those 50 years or older and of Asian ethnicity had lower smoking rates. These findings provide programmatic insights for the Asbestos Medical Surveillance Program and suggest areas for further study.

Adult↗
PubMed1999

Evidence for clonal outgrowth of androgen-independent prostate cancer cells from androgen-dependent tumors through a two-step process.

Prostate cancers require androgen for growth but progress to an androgen-independent stage under the selective pressure of androgen ablation therapy. Here we describe a novel human prostate cancer xenograft (LAPC-9) propagated by serial passage in male severe combined immunodeficient mice that expresses prostate-specific antigen and wild-type androgen receptor. In response to castration, LAPC-9 cells undergo growth arrest and persist in a dormant, androgen-responsive state for at least 6 months. After prolonged periods of androgen deprivation, spontaneous androgen-independent outgrowths develop. Thus, prostate cancers progress to androgen independence through two distinct stages, initially escaping dependence on androgen for survival and, subsequently, for growth. Through the use of serial dilution and fluctuation analysis, we provide evidence that the latter stage of androgen independence results from clonal expansion of androgen-independent cells that are present at a frequency of about 1 per 10(5)-10(6) androgen-dependent cells. We conclude that prostate cancers contain heterogeneous mixtures of cells that vary in their dependence on androgen for growth and survival and that treatment with antiandrogen therapy provides selective pressure and alters the relative frequency of these cells, thereby leading to outgrowths of androgen-independent cancers.

Androgens↗
PubMed1999

Accumulation and retention of micellar beta-carotene and lutein by Caco-2 human intestinal cells.

Despite the interest in the diverse roles of dietary carotenoids in human health, little is known about the transfer of these plant pigments from foods to micelles during digestion and their subsequent transfer across the intestinal epithelium. We conducted this study to characterize the intestinal uptake of micellarized carotenoids using monolayers of differentiated Caco-2 human intestinal cells. Crystalline beta-carotene (BC) and lutein (LUT), solubilized in mixed micelles for delivery to cells, were stable in a tissue culture environment for 20 hours. Cellular accumulation of micellar BC and LUT was proportional to the media content of carotenoids at </=2 micromol/L and the length of exposure. Cellular accumulation of BC routinely exceeded LUT and was due in part to the enhanced efflux or possible metabolism of LUT. Cellular BC content increased in a curvilinear manner when cultures were incubated in micellar medium containing 2 to 27 micromol/L BC prepared from water miscible beadlets; cellular BC content was maximum when medium BC was >/=18 micromol/L. There was no indication that high levels of BC in medium or within cells adversely affected micellar LUT accumulation. These data support the use of the Caco-2 human cell line as a model for studying the intestinal uptake, absorption, and possible interactions of dietary carotenoids.

Journal Article↗
PubMed1999

A mechanism for hormone-independent prostate cancer through modulation of androgen receptor signaling by the HER-2/neu tyrosine kinase.

Prostate cancer progresses from a hormone-sensitive, androgen-dependent stage to a hormone-refractory, androgen-independent tumor. The androgen receptor pathway functions in these androgen-independent tumors despite anti-androgen therapy. In our LAPC-4 prostate cancer model, androgen-independent sublines expressed higher levels of the HER-2/neu receptor tyrosine kinase than their androgen-dependent counterparts. Forced overexpression of HER-2/neu in androgen-dependent prostate cancer cells allowed ligand-independent growth. HER-2/neu activated the androgen receptor pathway in the absence of ligand and synergized with low levels of androgen to 'superactivate' the pathway. By modulating the response to low doses of androgen, a tyrosine kinase receptor can restore androgen receptor function to prostate cancer cells, a finding directly related to the clinical progression of prostate cancer.

Androgens↗
PubMed1997

Women's health. The childbearing years and after.

Health and development planners have tended to see women primarily in context of their reproductive role. As a result, solutions to women's health needs have been restricted to expanding and improving maternal and child health systems. There has recently been a major shift in direction, largely because of the influence of the world conference on population and development held in Cairo in 1994. Dr Guiseppe Benagiano, director of the special programme of research, development and research training in human reproduction based at the WHO, says, "We need to remind ourselves constantly that reproductive health is not simply a biomedical issue but one with serious implications for our general health and by extension, for all our efforts in human social and economic development." The 1993 world development report on health identified the lack of a clear strategy for engaging women in health care and suggested that child health services, prenatal care, treatment of sexually transmitted diseases, and family planning services should be provided jointly at convenient times. In an example of this, the Chilean Institute of Reproductive Medicine now offers integrated family planning services at the same time as child health services, and Thailand is experimenting with mobile health clinics to reach women in their homes. As the proportion of elderly women increases, old age is increasingly being seen as a female issue. With the impact of urbanisation and industrialisation, more of these women are living isolated lives, often suffering from chronic debilitating diseases. In his opening statement to the global commission on women's health in April 1995 which focused on health conditions of women in old age, Dr Hiroshi Nakajima, the WHO's director general, said: "Our goal should not be solely to extend lives in the physical sense, but to ensure that the added years are worth living."

Alcohol Drinking↗
PubMed1997

Age effects on interrelationships between lung volume and heart rate during standing.

To determine the effects of aging and posture on the relationship between respiration and heart rate (HR), we collected 5 min of lung volume and R-R interval data from 7 young (27 +/- 3 yr, mean +/- SD) and 10 old (69 +/- 6 yr) healthy humans during spontaneous breathing while they were supine (SU) and standing (ST). Lung volume and HR power spectra and transfer functions between lung volume and HR were estimated. Age and position effects and age-position interactions were determined by analysis of variance for repeated measures. Older subjects had a lower and more variable respiration rate (P < 0.03, P < 0.04), but both age groups exhibited decreased rate of respiration and increased tidal volume with ST (P < 0.05, P < 0.005). ST decreased lung volume-to-HR transfer function magnitude in both groups (P < 0.07). The more marked age-related differences were in phase angle. Both SU and ST phase angles were greater in older subjects (P < 0.003). ST decreased phase angle in young but increased phase angle in older subjects (P < 0.001). In conclusion, respiration, and respiration-HR interrelationships are altered by aging, with increased time delays between lung volume and HR and altered relationships with ST.

Adult↗
PubMed1996

Age and autonomic effects on interrelationships between lung volume and heart rate.

To determine effects of aging and autonomic input on interrelationships between respiratory and heart rate variability, we collected 5 min of lung volume of R-R interval data from 7 young [27 +/- 3(SD) yr] and 10 older (69 +/- 6 yr) healthy supine humans before and after double pharmacological autonomic blockade with propranolol (0.2 mg/kg iv) and atropine (0.04 mg/kg iv). Estimates of respiratory and heart rate power spectra and linear transfer functions between the two groups were generated by Fourier analysis. Age, double blockade effects, the age-drug interactions were determined by analysis of variance for repeated measures. Basal R-R intervals were unaffected by age. Double blockade decreased R-R intervals and variability in both age groups (P < 0.0001), but R-R intervals decreased less in older than in young subjects (P < 0.0001). In contrast, basal respiratory intervals and standard deviation were greater in older subjects (P = 0.05) and were unaffected by double blockade in young and older subjects. Lung volume-to-heart rate spectral coherence was highest at frequencies associated with respiration and greater in young than in older subjects (P < 0.07). Double blockade decreased lung volume-to-heart rate variability transfer function magnitude (P < 0.007) and increased phase angle (P < 0.02) without age effects or age-drug interactions. In conclusion, heart rate, respiration, and respiration-heart rate interrelations are altered by aging, and double autonomic pharmacological blockade does not eliminate all age-related differences.

Adult↗
PubMed1995

Letter fraud.

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