Glutathione-S-transferase (GSTM1) genetic polymorphisms do not affect human breast cancer risk, regardless of dietary antioxidants.
(1/3881)
Glutathione-S-transferases catalyze the detoxication of carcinogen metabolites and reactive oxygen species (ROS) produced through a number of mechanisms. Glutathione-S-transferase (GST) M1 is polymorphic, and the null allele results in a lack of enzyme activity. Because there are indications that ROS may be involved in breast carcinogenesis, we sought to determine whether the GSTM1 null allele was associated with increased breast cancer, particularly among women with lower consumption of dietary sources of alpha-tocopherol, carotenoids and ascorbic acid. In a study of diet and cancer in western New York, women with primary, incident, histologically confirmed breast cancer (n = 740) and community controls (n = 810) were interviewed and an extensive food-frequency questionnaire administered. A subset of these women provided a blood specimen. DNA was extracted and genotyping performed for GSTM1. Data were available for 279 cases and 340 controls. The null allele did not increase breast cancer risk, regardless of menopausal status. There were also no differences in associations between the polymorphism and risk among lower and higher consumers of dietary sources of antioxidants or smokers and nonsmokers. These results indicate that GSTM1 genetic polymorphisms are not associated with breast cancer risk, even in an environment low in antioxidant defenses. (+info)
Tumour necrosis factor-alpha (TNF-alpha) in human endometrium and uterine secretion: an evaluation by immunohistochemistry, ELISA and semiquantitative RT-PCR.
(2/3881)
Tumour necrosis factor-alpha (TNF-alpha is a pleiotropic cytokine synthesized throughout the female reproductive tract. Even though evidence has accumulated that supports its role in autocrine and paracrine processes, its expression and function in the human endometrium are still not completely understood. To gain a better understanding of the synthesis and release of TNF-alpha in the endometrium and how this relates to concentrations in uterine secretion, its expression throughout the menstrual cycle was investigated by three different techniques. Samples of endometrial tissue and uterine secretions were collected from patients undergoing abdominal and vaginal hysterectomy for benign reasons. The mRNA expression of TNF-alpha was investigated in homogenized endometrial tissue by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) (n = 18). An assessment of the cellular TNF-alpha protein localization in the endometrial glands was performed immunohistochemically (n = 39). The concentrations of the secreted TNF-alpha protein in endometrial secretion were determined by enzyme-linked immunosorbent analysis (n = 30). All three methods gave similar results on the temporal expression of TNF-alpha mRNA and TNF-alpha protein during the cycle. Concentrations of endometrial TNF-alpha mRNA in tissue samples and TNF-alpha protein in uterine secretion were quite low at the beginning of the cycle, rose sharply in the mid- to late proliferative phase and decreased towards the end of the cycle. The concentrations of TNF-alpha protein in the endometrial glands, as shown by immunohistochemical investigation, stayed high throughout the secretory phase at values slightly below those of the late proliferative phase. (+info)
Cyclical etidronate increases bone density in the spine and hip of postmenopausal women receiving long term corticosteroid treatment. A double blind, randomised placebo controlled study.
(3/3881)
OBJECTIVE: To study the effect of cyclic etidronate in secondary prevention of corticosteroid induced osteoporosis. METHODS: A double blind, randomised placebo controlled study comparing cyclic etidronate and placebo during two years in 37 postmenopausal women receiving long term corticosteroid treatment, mainly for polymyalgia rheumatica (40% of the patients) and rheumatoid arthritis (30%). Bone density was measured in the lumbar spine, femoral neck, and femoral trochanter. RESULTS: After two years of treatment there was a significant difference between the groups in mean per cent change from baseline in bone density in the spine in favour of etidronate (p = 0.003). The estimated treatment difference (mean (SD)) was 9.3 (2.1)%. Etidronate increased bone density in the spine (4.9 (2.1)%, p < 0.05) whereas the placebo group lost bone (-2.4 (1.6)%). At the femoral neck there was an estimated difference of 5.3 (2.6)% between the groups (etidronate: 3.6% (1.4)%, p < 0.05, placebo: -2.4 (2.1)%). The estimated difference at the trochanter was 8.2 (3.0) (etidronate: 9.0 (1.5)%, p < 0.0001, placebo: 0.5 (2.3)%). No significant bone loss occurred in the hip in placebo treated patients. CONCLUSIONS: Cyclic etidronate is an effective treatment for postmenopausal women receiving corticosteroid treatment and is well tolerated. (+info)
Expression of prostate-specific antigen (PSA) correlates with poor response to tamoxifen therapy in recurrent breast cancer.
(4/3881)
Prostate-specific antigen (PSA) is a serine protease which may play a role in a variety of cancer types, including breast cancer. In the present study, we evaluated whether the level of PSA in breast tumour cytosol could be associated with prognosis in primary breast cancer, or with response to tamoxifen therapy in recurrent disease. PSA levels were determined by enzyme-linked immunosorbent assay (ELISA) in breast tumour cytosols, and were correlated with prognosis in 1516 patients with primary breast cancer and with response to first-line tamoxifen therapy in 434 patients with recurrent disease. Relating the levels of PSA with classical prognostic factors, low levels were more often found in larger tumours, tumours of older and post-menopausal patients, and in steroid hormone receptor-negative tumours. There was no significant association between the levels of PSA with grade of differentiation or the number of involved lymph nodes. In patients with primary breast cancer, PSA was not significantly related to the rate of relapse, and a positive association of PSA with an improved survival could be attributed to its relationship to age. In patients with recurrent breast cancer, a high level of PSA was significantly related to a poor response to tamoxifen therapy, and a short progression-free and overall survival after start of treatment for recurrent disease. In Cox multivariate analyses for response to therapy and for (progression-free) survival, corrected for age/menopausal status, disease-free interval, site of relapse and steroid hormone receptor status, PSA was an independent variable of poor prognosis. It is concluded that the level of PSA in cytosols of primary breast tumours might be a marker to select breast cancer patients who may benefit from systemic tamoxifen therapy. (+info)
Menopausal status and distensibility of the common carotid artery.
(5/3881)
Although several studies have shown that exogenous estrogens have beneficial effects on arterial characteristics, the effect of endogenous estrogen on the vascular system is still unknown. In this study, distensibility, an indicator of arterial elasticity, of the common carotid artery was compared in pre- and postmenopausal women. The study comprised 93 premenopausal and 93 postmenopausal women of similar age (range, 43 to 55 years). Women were selected from respondents to a mailed questionnaire about the menopause, which was sent to all women aged 40 to 60 years in the Dutch town of Zoetermeer (n=12 675). Postmenopausal women who were at least 3 years past natural menopause or whose menses had stopped naturally before age 48, were age-matched with premenopausal women with regular menses and without menopausal complaints. The selection aimed at maximizing the contrast in estrogen status between pre- and postmenopausal women of the same age. Distensibility of the carotid artery was measured noninvasively with B-mode ultrasound and a vessel wall movement detector system. Arterial distensibility is expressed as the change in arterial diameter (distension, DeltaD) with the cardiac cycle, adjusted for lumen diameter, pulse pressure, and mean arterial blood pressure. Compared with premenopausal women, postmenopausal women had significantly lower arterial distension (DeltaD 370.5 microm [SE 9.5] versus 397.3 microm [SE 9.6]). These results suggest that the distensibility of the common carotid artery is negatively affected by natural menopause in presumed healthy women. (+info)
Health aspects of partially defatted flaxseed, including effects on serum lipids, oxidative measures, and ex vivo androgen and progestin activity: a controlled crossover trial.
(6/3881)
BACKGROUND: Currently there is considerable interest in the potential health benefits of oil seeds, such as soy and flaxseed, especially in relation to cardiovascular disease and cancer. OBJECTIVE: We therefore evaluated health aspects of partially defatted flaxseed in relation to serum lipids, indicators of oxidative stress, and ex vivo sex hormone activities. DESIGN: Twenty-nine hyperlipidemic subjects (22 men and 7 postmenopausal women) completed two 3-wk treatment periods in a randomized, crossover trial. Subjects were given muffins that contributed approximately 20 g fiber/d from either flaxseed (approximately 50 g partially defatted flaxseed/d) or wheat bran (control) while they consumed self-selected National Cholesterol Education Program Step II diets. Both muffins had similar macronutrient profiles. Treatment phases were separated by > or = 2 wk. RESULTS: Partially defatted flaxseed reduced total cholesterol (4.6+/-1.2%; P = 0.001), LDL cholesterol (7.6+/-1.8%; P < 0.001), apolipoprotein B (5.4+/-1.4%; P = 0.001), and apolipoprotein A-I (5.8+/-1.9%; P = 0.005), but had no effect on serum lipoprotein ratios at week 3 compared with the control. There were no significant effects on serum HDL cholesterol, serum protein carbonyl content, or ex vivo androgen or progestin activity after either treatment. Unexpectedly, serum protein thiol groups were significantly lower (10.8+/-3.6%; P = 0.007) at week 3 after the flaxseed treatment than after the control, suggesting increased oxidation. CONCLUSIONS: These data indicate that partially defatted flaxseed is effective in lowering LDL cholesterol. No effects on lipoprotein ratios, ex vivo serum androgen or progestin activity, or protein carbonyl content were observed. The significance of increased oxidation of protein thiol groups with flaxseed consumption requires further investigation. (+info)
Hormone replacement therapy increases isometric muscle strength of adductor pollicis in post-menopausal women.
(7/3881)
A randomized open trial of hormone replacement therapy was used to assess changes in adductor pollicis muscle strength during 6-12 months of treatment with Prempak C 0.625(R) in comparison with an untreated control group. Muscle strength (maximal voluntary force; MVF), muscle cross-sectional area and bone mineral density were measured. Women entering the trial had oestrogen levels below 150 pmol.l-1, confirming their post-menopausal hormonal status. In the treated group, MVF increased by 12.4+/-1.0% (mean+/-S.E.M.) of initial MVF over the duration of treatment, while it declined slightly (2.9+/-0.9%) in the control group. This increase in strength could not be explained by an increase in muscle bulk, there being no significant increase in cross-sectional area during the study. Those subjects who were weakest at enrolment showed the greatest increases in muscle strength after treatment. Bone mineral density in total hip, Ward's triangle and total spine increased in the treated group, in agreement with previous studies. There was no correlation between the individual increases in bone mineral density and those in MVF. (+info)
Meta-analysis: dietary fat intake, serum estrogen levels, and the risk of breast cancer.
(8/3881)
BACKGROUND: There is compelling evidence that estrogens influence breast cancer risk. Since the mid-1980s, dietary fat intervention studies have been conducted to investigate the effect of fat intake on endogenous estrogen levels. To further our understanding of the possible relationship between dietary fat and breast cancer, we conducted a meta-analysis of dietary fat intervention studies that investigated serum estradiol levels, and we reviewed the nature of the evidence provided by prospective analytic studies of fat consumption and breast cancer risk. METHODS: A computerized search of the English language literature on estrogen/estradiol and dietary fat intervention studies published from January 1966 through June 1998 was conducted using the MEDLINE database. Pooled estimates were derived from the change in estradiol levels associated with fat reduction from 13 studies. Analyses were conducted separately for premenopausal and postmenopausal women and in both groups combined. RESULTS AND CONCLUSIONS: Statistically significant reductions in serum estradiol levels of -7.4% (95% confidence interval [CI] = -11.7% to -2.9%) among premenopausal women and -23.0% (95% CI = -27.7% to -18.1%) among postmenopausal women were observed, with an overall -13.4% (95% CI = -16.6% to -10.1%) reduction observed. The greatest reductions occurred in two studies in which dietary fat was reduced to 10%-12% of calories compared with 18%-25% of calories in the other studies. A statistically significant reduction in estradiol levels of -6.6% (95% CI = -10.3% to -2.7%) remained after exclusion of these two studies. Review of prospective analytic epidemiologic studies that allowed for dietary measurement error suggests that the possibility that reducing fat consumption below 20% of calories will reduce breast cancer risk cannot be excluded. IMPLICATIONS: Dietary fat reduction can result in a lowering of serum estradiol levels and such dietary modification may still offer an approach to breast cancer prevention. (+info)