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Biomedical subjects

L Bernstein

Publications and source records attributed to L Bernstein.

At least 127 records · Page 7Linked to original sources
PubMed1992

Abnormalities of diastolic filling of the left ventricle associated with aging are less pronounced in exercise-trained individuals.

To determine whether exercise training has an effect on left ventricular diastolic dysfunction associated with the normal aging process, we studied a group of 20 normal healthy adult distance runners (mean miles currently run per week was 45 for an average of 15 years) and 20 normal healthy sedentary individuals (who currently walk less than 1 mile per day and are not involved in a regular exercise program) matched for age and systolic and diastolic blood pressure with the runners. Doppler echocardiographic indices of left ventricular diastolic filling were significantly different between the two groups. The exercise group when compared with the sedentary group had significantly decreased late diastolic peak filling velocity (0.51 +/- 0.11 m/sec versus 0.66 +/- 0.20 m/sec; p = 0.003), late diastolic velocity-time integral (5.2 +/- 1.5 cm versus 6.6 +/- 2.2 cm; p = 0.02), increased early-to-late peak filling velocity ratio (1.29 +/- 0.38 versus 0.96 +/- 0.24; p = 0.001), and early-to-late velocity-time integral ratio (2.08 +/- 0.51 versus 1.42 +/- 0.47; p less than 0.001). We conclude that the left ventricular diastolic dysfunction associated with "normal" aging is less pronounced in those persons who are exercise-trained.

Aging↗
PubMed1992

Behavioral stress responses in premenopausal and postmenopausal women and the effects of estrogen.

OBJECTIVE: Our purpose was to determine the pattern of reactivity to stress in premenopausal and postmenopausal women and to assess the effects of estrogen. STUDY DESIGN: A behavioral stress test was given to premenopausal (n = 13) and postmenopausal women (n = 36). Biophysical and neuroendocrine responses were measured during and on completion of the stress test. The postmenopausal women were then randomized to placebo or transdermal estradiol treatment for 6 weeks, at which time another behavioral stress test was given. RESULTS: Stress reactivity to math and speech tasks elicited significantly greater systolic blood pressure responses in postmenopausal women compared with premenopausal women (p < 0.05). On retesting, significant biophysical responses that were present during the initial stress testing were still present (p < 0.05) in the placebo group but were blunted with estrogen treatment. Plasma corticotropin, cortisol, androstenedione, and norepinephrine increased during testing to a similar degree in premenopausal and postmenopausal women; this response was maintained after placebo treatment. Postmenopausal women treated with estrogen had blunted responses. CONCLUSION: Significant differences in responses to psychologic stress exist in premenopausal and postmenopausal women. The lack of adaptation may account in part for the increased risk of cardiovascular disease in postmenopausal women. Estrogen appears to blunt the stress-induced response.

Aged↗
PubMed1992

Stage and delay in breast cancer diagnosis by race, socioeconomic status, age and year.

Information on 23,567 Non-Hispanic White, 2,539 Black, and 2,380 Hispanic breast cancer cases diagnosed between 1977 and 1985 was used to evaluate the risk of late stage diagnosis and long duration of symptoms prior to diagnosis in relation to ethnicity, socioeconomic status, age and year of diagnosis. All data were collected by the University of Southern California Cancer Surveillance Program, the comprehensive population-based incidence registry of Los Angeles County. The results indicate that lower socioeconomic status, Black or Hispanic ethnicity, younger age, and earlier year of diagnosis are risk factors for late stage diagnosis and long duration of symptoms. The effect of ethnicity was not explained by lower SES levels among Black or Hispanic women. After controlling for duration of symptoms, race and SES remained significantly predictive of more advanced stage. More recent diagnosis across the 9 year time frame was not associated with improved stage for those of low SES. These results suggest that increased efforts are needed to reach low SES and Black and Hispanic women with campaigns to improve the stage at which breast cancer is detected.

Adult↗
PubMed1992

Detection of alcoholism among burn patients.

To determine the prevalence of alcoholism among patients at a large inpatient burn center, a semistructured interview for diagnosing alcoholism--the CAGE questionnaire--was administered. Of 124 patients interviewed, 24 (19 percent) were found to have an alcohol problem based on responses to the CAGE questionnaire. However, when patients' charts were reviewed at discharge, only seven of the 24 subjects were described as having an alcohol-related problem. Of the 22 subjects whose alcoholism was detected by the CAGE questionnaire and for whom blood alcohol screens had been obtained on admission, only seven had a positive screen. About 70 percent of the patients with alcoholism were missed by blood alcohol screens on admission and by the usual procedures for gathering patient information on admission and during hospitalization. The study found that use of the CAGE questionnaire greatly increased the detection of alcoholism in burn patients.

Adolescent↗
PubMed1992

Lp(a) lipoprotein: relationship to cardiovascular disease risk factors, exercise, and estrogen.

OBJECTIVE: Lp(a) lipoprotein is a distinct lipoprotein particle that recently has been found to be associated with cardiovascular disease. A study was conducted to assess the influence of cardiovascular disease risk factors on levels of Lp(a) and to evaluate the effects of age, exercise, and estrogen on these levels. STUDY DESIGN: Two studies, a cross-sectional study of older men (n = 105) and women (n = 75) (mean age 76 years) and a prospective study of younger postmenopausal women (mean age 48 years), were carried out. Lp(a) and other lipoproteins were measured in the two studies and differences were sought by statistical analysis. RESULTS: In the cross-sectional study, serum Lp(a) was similar in men and women and was not influenced by age. Lp(a) levels in men and women were higher when there was more than one cardiovascular disease risk factor present (p less than 0.028). We could not demonstrate such a relationship with other lipid and lipoprotein measurements. In the prospective study exercise alone had no influence on Lp(a) levels. Oral estrogen decreased Lp(a) levels marginally (p = 0.08). The decrease in Lp(a) with oral estrogen was associated with increases in triglycerides (p less than 0.01) and very-low-density lipoprotein (p less than 0.06). CONCLUSIONS: These data confirm that elevated Lp(a) levels are an independent risk factor for cardiovascular disease. Lp(a) levels are primarily influenced by genetic factors and it appears estrogen may have a minor influence on its hepatic synthesis.

Aging↗
PubMed1992

Relationship of hormone use to cancer risk.

Exogenous hormones are widely prescribed in the United States, primarily as oral contraceptives and hormone-replacement therapy. Each of these frequently used categories of drugs has important potential for altering risk of several major human cancers. The efficacy of oral contraceptives in preventing ovarian cancer and endometrial cancer is well established. There remains controversy about the relationship between oral-contraceptive use and breast cancer risk, but most studies show that use in the postmenarcheal and perimenopausal periods is associated with an increased risk of breast cancer in a duration-dependent manner. As with oral contraceptives, the relationship between estrogen-replacement therapy and breast cancer risk is controversial, but several well-designed studies showed a moderate increased risk after long-term use. Estrogen-replacement therapy is a major cause of endometrial cancer. Combination hormone-replacement therapy will probably reduce some of the excess risk of endometrial cancer, but few epidemiological data exist on this relationship. The sparse data suggest that combination therapy may enhance breast cancer risk. As with endometrial and ovarian cancers, hormonal chemoprevention of breast cancer is also feasible. We review two such strategies, ie, gonadotropin-releasing hormone agonists and the antiestrogenic drug tamoxifen.

Adolescent↗
PubMed1991

Occupational asbestos exposure and mesothelioma risk in Los Angeles County: application of an occupational hazard survey job-exposure matrix.

We evaluated the newly available National Institute for Occupational Safety and Health (NIOSH) National Occupational Hazard Survey (NOHS) job exposure matrix (JEM) by considering mesothelioma risk from asbestos exposure. We applied this system (NOHS-JEM) to the Los Angeles County Cancer Surveillance Program (CSP) to see how many cancer cases could be assigned asbestos exposure and how asbestos exposure affected mesothelioma risk. Using the same CSP data, our "experts" classified asbestos exposure simply by occupation and industry. Both exposure classifications were divided into low and high; the NOHS-JEM by the number of exposed people per couplet, and ours by judgements of intensity. Odds ratios (OR) for mesothelioma risk for low and high asbestos exposure for the NOHS-JEM were 2.0 (95% C.I. 1.2-3.4) and 2.5 (95% C.I. 1.2-4.8). For ours, corresponding risks were 1.6 (95% C.I. 1.1-2.4) and 6.3 (95% C.I. 2.5-15.1). Our system was able to assign more cases to couplets then the NOHS-JEM (35,895 to 22,369). Three limitations of the NOHS-JEM were that many occupation-industry couplets were not classified at all, many couplets associated with past asbestos exposure (before the 1972-1974 NOHS survey) were not classified as asbestos exposure, and no assessment of intensity was made. These limitations may apply to other exposures and should be carefully considered before the NOHS-JEM is applied to other case-control studies.

Adolescent↗
PubMed1991

Age at menarche and estrogen concentrations of adult women.

It has recently been reported that women with a recorded early menarche had approximately two-fold greater follicular phase serum E2 (estradiol) levels than women with menarche at age 13 or later. We have evaluated E1 (estrone) and E2 concentrations in the blood, and estrogen concentrations in the urine, in two groups of premenopausal women (mean ages 33 and 38 years) for categories of age at menarche. Study subjects were 106 Caucasian women in the United States (assessed for E1, E2, and urinary estrogens) and 39 women from Shanghai, China (assessed for E2). US subjects were classified according to whether their recalled menarche occurred before age 12, at age 12, or at age 13 or older. The mean age at recalled menarche of the Shanghai subjects was considerably older, and their ages at menarche were classified as less than age 15, age 15, and age 16 or older. We found little evidence in these premenopausal women in their thirties of an effect of age at menarche on estrogen levels. A large-scale study of women in the age range 20-40 years is necessary to investigate this important issue more thoroughly.

Adult↗
PubMed1991

The international variation in breast cancer rates: an epidemiological assessment.

Part of the international differences in breast cancer incidence rates can be explained by geographic variation in reproductive and other breast cancer risk factors. Age at menarche and age at onset of regular ovulatory menstrual cycles are two such factors; both vary across populations directly according to breast cancer risk, and both are acknowledged as breast cancer risk factors. Consideration of the body of evidence on these factors, as well as that on age at menopause, suggests that the cumulative frequency of ovulatory menstrual cycles is a critical determinant of breast cancer risk. Although age at first term pregnancy explains the majority of the protective effect of parity on breast cancer risk, two recent studies have demonstrated a small residual protective effect of increasing number of births. It appears that pregnancy has paradoxical effects on breast cancer risk in terms of hormone production and metabolism. The initial effect is an increased risk associated with first trimester estrogen exposure. However, the hormonal consequences of completing the pregnancy counteract this negative effect of early pregnancy. The effect of body weight, a breast cancer risk factor for postmenopausal women, can be explained in terms of increased extraglandular conversion of androstenedione to estrone. Further evidence supporting a pathogenic role of estrogens in the development of breast cancer comes from international studies of endogenous hormones in populations with differing risks of breast cancer. These risk factors have been incorporated into a mathematical model which is based on the concept that breast tissue ages according to hormonal (primarily estrogen) exposure; this model closely predicts the incidence rates throughout the world.

Age Factors↗
PubMed1991

Cancers of the prostate and breast among Japanese and white immigrants in Los Angeles County.

Using age-adjusted incidence rates and proportional incidence ratios, the risks of prostate cancer and breast cancer in three racial/ethnic groups - Spanish-surnamed whites, other whites and Japanese - were studied in Los Angeles County native residents and compared with those in immigrants and representative 'homeland' populations. An algorithm based on social security numbers was developed and utilised to estimate age at immigration for non-US-born Los Angeles County cancer patients. For prostate cancer, the incidence rates in Los Angeles County were much higher than those in the homelands for each racial/ethnic group. However, prostate cancer rates of immigrants were similar to those of US-born patients in the Spanish-surnamed white and Japanese populations, regardless of age at immigration. For breast cancer, the incidence rates in Los Angeles County were also high compared with those in the homelands. However, the timing of immigration to the US was important in determining breast cancer risk. When social security numbers indicated that migration occurred later in life, rates for breast cancer were substantially lower than when migration occurred early, although they were still much higher than in the homeland populations. These findings suggest that environmental factors in early life rather than in later life are important in the etiology of breast cancer and that later life events can substantially impact the likelihood of developing clinically detectable prostate cancer.

Age Factors↗