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Biomedical subjects

J A Bean

Publications and source records attributed to J A Bean.

At least 19 recordsLinked to original sources
PubMed1999

Cigarette smoking, alcohol use, and physical activity in relation to serum leptin levels in a multiethnic population: The Miami Community Health Study.

PURPOSE: To examine the correlates of plasma leptin, including fasting insulin, adiposity, and several health habits and behaviors among a nondiabetic multiethnic population. METHODS: A cross-sectional study was conducted among 25-44 year old African-Americans (n = 126), Cuban-Americans (n = 107), and non-Hispanic whites (n = 189) randomly selected from Dade County Florida. Fasting leptin levels were correlated with fasting insulin, percent body fat, smoking, alcohol use, and physical activity within each sex. Multiple linear regression and analysis of covariance were used to estimate the independent determinants of plasma leptin concentration separately among men and women. RESULTS: Stepwise linear regression analyses revealed statistically significant associations of leptin with percent body fat, fasting insulin, cigarette smoking, and physical activity (both inversely) among men (p < 0.05 for each). Among women, percent body fat, fasting insulin (both positively), cigarette smoking, and alcohol use (inversely) were independent predictors of leptin levels explaining over 70% of the variance. Analyses of covariance revealed that women had higher adjusted mean leptin levels than men (13.1 ng/ml vs. 5.9 ng/ml; p < 0.001), whereas no separate effect of ethnicity was noted. CONCLUSIONS: Although adiposity was the strongest correlate of leptin levels, fasting insulin and several health habits and behaviors were independently associated with leptin. After adjustment for these factors, women had significantly higher mean leptin levels than men. The independent association among leptin and insulin levels is intriguing and suggests additional avenues for epidemiologic research.

Adult↗
PubMed1999

Cancer incidence in a cohort of licensed pesticide applicators in Florida.

This study is a standardized incidence ratio (SIR) analysis of cancer incidence of licensed pesticide applicators in Florida, compared with that of Florida's general population. Through extensive data linkages, 33,658 applicators were assembled who had 1266 incident cancers and 279,397 person-years from January 1, 1975, to December 31, 1993. Disease risk from ethanol and tobacco use were significantly decreased. Among males, prostate cancer (SIR = 1.91; 95% confidence interval [CI], 1.72-2.13) and testicular cancer (SIR = 2.48; 95% CI, 1.57-3.72) were significantly elevated. No confirmed cases of soft tissue sarcoma (STS) were found, and the incidence of non-Hodgkin's lymphoma was not increased. There were few female applicators; nevertheless, cervical cancer incidence (SIR = 3.69; 95% CI, 1.84-6.61) was significantly increased, while the incidence of breast cancer was significantly decreased. Cancers that have been associated with estrogen disrupters were found in male, but not female, pesticide applicators. The lack of soft tissue sarcoma is at odds with prior literature associated with the use of phenoxy herbicides.

Adult↗
PubMed1999

Antibody-dependent and -independent protection following intranasal immunization of mice with rotavirus particles.

The ability to elicit protective immune responses after intranasal immunization with rotavirus particles, either with or without the attenuated Escherichia coli heat-labile enterotoxin LT(R192G) as an adjuvant, was examined in the adult mouse model. BALB/c mice were administered one or two inoculations of psoralen/UV-inactivated, triple-layered (tl) or double-layered (dl) purified rotavirus particles. Four weeks after immunization, mice were challenged with the murine rotavirus strain EDIM, and the shedding of rotavirus antigen was quantified. Rotaviruses used for immunization included EDIM and heterotypic simian (RRV), bovine (WC3), and human (89-12) strains. tl EDIM stimulated both systemic and intestinal rotavirus antibody responses and complete protection with as little as one 1-microgram dose. Inclusion of LT(R192G) (10 micrograms) significantly increased rotavirus antibody responses and reduced antigen concentrations needed for full protection. Both dl EDIM and heterotypic dl and tl particles stimulated protection, but they did so less than tl EDIM at comparable concentrations, either with or without LT(R192G). When B-cell-deficient microMt mice were immunized with tl EDIM particles, protection was reduced to levels similar to those induced with dl EDIM and heterotypic particles in BALB/c mice. However, dl EDIM particles induced similar levels of protection in both mouse strains. The protection stimulated by tl or dl EDIM particles was not diminished by CD8 cell depletion prior to immunization in either strain of mice. These results indicate that tl EDIM induced immunity at least partially through responses to its outer capsid proteins, presumably by stimulation of serotype-specific neutralizing antibody. In contrast, the other particles stimulated protection primarily by an antibody-independent mechanism. Finally, depletion of CD8 cells had no effect on protection by either mechanism.

Adjuvants, Immunologic↗
PubMed1999

Mortality in a cohort of licensed pesticide applicators in Florida.

OBJECTIVES: Although the primary hazard to humans associated with pesticide exposure is acute poisoning, there has been considerable concern surrounding the possibility of cancer and other chronic health effects in humans. Given the huge volume of pesticides now used throughout the world, as well as environmental and food residue contamination leading to chronic low level exposure, the study of possible chronic human health effects is important. METHODS: This was a retrospective cohort study, analysed by general standardised mortality ratio (SMR) of licensed pesticide applicators in Florida compared with the general population of Florida. A cohort of 33,658 (10% female) licensed pesticide applicators assembled through extensive data linkages yielded 1874 deaths with 320,250 person-years from 1 January 1975 to 31 December 1993. RESULTS: The pesticide applicators were consistently and significantly healthier than the general population of Florida. As with many occupational cohorts, the risks of cardiovascular disease and of diseases associated with alcohol and tobacco use were significantly lower, even in the subpopulations--for example, men, women, and licence subcategories. Among male applicators, prostate cancer mortality (SMR 2.38 (95% confidence interval (95% CI) 1.83 to 3.04) was significantly increased. No cases of soft tissue sarcoma were confirmed in this cohort, and non-Hodgkin's lymphoma was not increased. The number of female applicators was small, as were the numbers of deaths. Mortality from cervical cancer and breast cancer was not increased. Additional subcohort and exposure analyses were performed. CONCLUSIONS: Consistent with previous publications on farmers but at odds with current theories about the protective effects of vitamin D, prostate cancer was increased in these pesticide applicators. Female breast cancer was not increased despite theories linking risk of breast cancer with exposure to oestrogen disruptors--such as the organochlorines. The lack of cases of soft tissue sarcoma is at odds with previous publications associating the use of the phenoxy herbicides with an increased risk of these cancers.

Adult↗
PubMed1999

Is fasting leptin associated with insulin resistance among nondiabetic individuals? The Miami Community Health Study.

OBJECTIVE: Whether serum leptin levels are associated with insulin resistance independent of the effects of hyperinsulinemia and adiposity is an important unanswered question. We examined the relationship between the rate of insulin-mediated glucose uptake and serum leptin concentrations among nondiabetic men and women. RESEARCH DESIGN AND METHODS: A cross-sectional analysis was performed among 49 young to middle-aged men and women who participated in the Miami Community Health Study. All participants had measures of insulin resistance (euglycemic-hyperinsulinemic clamp), postchallenge insulin levels, fasting serum leptin levels, and several measures of adiposity. RESULTS: The rate of insulin-mediated glucose uptake (M in milligrams per kilogram per minute) was significantly associated with leptin concentrations in both men (r = -0.83; P < 0.001) and women (r = -0.59; P < 0.001). M was also inversely related to percent body fat and to the 2-h insulin area under the curve (AUC). After covariate adjustment for sex, percent body fat, and AUC, leptin remained a significant correlate of M (P = 0.04). CONCLUSIONS: Cross-sectionally, leptin was significantly associated with insulin resistance in this nondiabetic sample of men and women. There may be a different physiological mechanism to explain the leptin/insulin resistance association apart from the insulin/adiposity link. Confirmatory evidence awaits the results of clinical trials.

Adult↗
PubMed1998

The relation of fasting insulin to blood pressure in a multiethnic population: the Miami Community Health Study.

PURPOSE: The aim of this study was to examine the associations among fasting insulin, adiposity, waist girth, and blood pressure among a nondiabetic multiethnic population. METHODS: A cross-sectional study was performed among 25-44-year-old African-Americans (n = 159), Cuban-Americans (n = 128), and non-Hispanic whites (n = 207) selected from Dade County, Florida. Fasting insulin levels were correlated with resting blood pressure level within each ethnic group. The separate effects of percentage body fat and waist girth on the association between blood pressure and insulin were analyzed in multiple linear regression and analysis of covariance. RESULTS: Fasting insulin was positively associated with systolic (r = 0.26-0.39; P < 0.01) and diastolic blood pressure (r = 0.19-0.30; P = 0.10 to P < 0.001) among women of all ethnic groups and among non-Hispanic white men (r = 0.27; P < 0.05). Stepwise linear regression analyses revealed statistically significant associations between systolic and diastolic blood pressure and fasting insulin level in non-Hispanic whites independent of other covariates, including sex and percentage body fat (P < 0.001). Fasting insulin was also independently and significantly related to systolic blood pressure among African-Americans (P = 0.02). Among Cuban-Americans, sex and percentage body fat were the main correlates of blood pressure level. Analysis of covariance revealed a relationship between insulin and blood pressure that was independent of waist girth among men and women. CONCLUSIONS: Fasting insulin level and blood pressure were positively associated among African-Americans and non-Hispanic whites. This association was not entirely due to the common association with percentage body fat or waist girth.

Adipose Tissue↗
PubMed1997

Does insulin resistance unite the separate components of the insulin resistance syndrome? Evidence from the Miami Community Health Study.

A number of coronary heart disease risk factors have been identified that often cluster together to increase the risk of macrovascular disease. This cluster is referred to as the insulin resistance syndrome, and the risk factors commonly include dyslipidemia, elevated blood pressure, an android pattern of body fat distribution, and glucose intolerance. Whether hyperinsulinemia or insulin resistance per se provides a common pathway for these metabolic abnormalities is unclear. The authors studied 50 nondiabetic persons who had completed a euglycemic hyperinsulinemic clamp protocol in addition to a 75-g oral glucose tolerance test and other measures of the coronary risk profile. Using principal-component analysis, we reduced nine coronary risk factors to two uncorrelated factors that explained 54.5% of the variance. Factor 1 consisted of positive loadings for uric acid, systolic and diastolic blood pressure, triglyceride concentration, and waist girth and negative loadings for HDL cholesterol and the rate of insulin-mediated glucose disposal (M, in milligrams per kilogram of body weight per minute). M also loaded on factor 2, along with fasting insulin and glucose concentrations, diastolic blood pressure, and waist girth. The observation that M loaded on both factors suggests that a resistance to insulin action may provide the mechanism uniting the features of the insulin resistance syndrome. Hyperinsulinemia with concomitant insulin resistance may be necessary to produce this metabolic derangement, as well as the increased risk of macrovascular complications.

Adult↗
PubMed1997

Insulin response in a triethnic population: effects of sex, ethnic origin, and body fat. Miami Community Health Study.

OBJECTIVE: To assess sex and ethnic differences in hyperinsulinemia/insulin resistance and to examine the impact of percent body fat on such differences. RESEARCH DESIGN AND METHODS: A cross-sectional epidemiological study was performed in a normoglycemic population of African-Americans (n = 159), Cuban Americans (n = 128), and non-Hispanic whites (n = 207) who resided in Dade County, Florida, from 1990 to 1995. The insulin area under the curve (AUC) in response to a standard 75-g oral glucose tolerance test (OGTT) was used as an indicator of hyperinsulinemia/insulin resistance. Analysis of covariance was performed to compare sex and ethnic differences in the insulin AUC. Multiple linear regression was used to evaluate the independent correlates of the insulin AUC. RESULTS: After covariate adjustment for percent body fat, men displayed a significantly higher insulin AUC than did women (P < 0.001). African-Americans and Cuban-Americans each had a significantly higher insulin AUC than did non-Hispanic white participants (P = 0.01). Alcohol consumption was inversely related to AUC (P = 0.04). CONCLUSIONS: Despite the greater percentage of body fat in women, the insulin AUC was similar in women and men. After adjustment for the sex difference in percent body fat, women displayed a lower insulin AUC than did men, indicating enhanced insulin sensitivity. These differences by sex and ethnicity in insulin resistance are consistent with established differences in heart-disease risk (i.e., higher in men and African-Americans) and suggest that hyperinsulinemia/insulin resistance may partly underlie such differences.

Adult↗
PubMed1996

Internal tremor in patients with Parkinson's disease.

Although sensory symptoms were not originally described in Parkinson's disease (PD), in recent years it has been increasingly recognized that painful sensations and paresthesias occur in approximately 40% of patients. It has been our observation that PD patients often describe a sensation of internal tremor, a feeling of tremor inside the chest, abdomen, arms, or legs that cannot be seen. We investigated the prevalence and characteristics of internal tremor by administering a questionnaire to 100 consecutive patients with PD and 50 age-matched controls seen in our movement disorders center. A sensation of internal tremor was present in 44% of this sample of PD patients and in 6% of the control population (p < 0.0001). The presence of internal tremor was unrelated to Unified Parkinson's Disease Rating Scale score, Hoehn and Yahr stage, duration of disease, or the presence of observable tremor. The frequency of other sensory symptoms (aching, tingling, burning) was higher in the PD patients with internal tremor (73%) than in those without (45%; p = 0.005). Internal tremor is associated with anxiety in 64% of patients (p < 0.0001). It was described as uncomfortable and was unrelieved by antiparkinsonian medication in three quarters of patients. A sensation of internal tremor is commonly reported by PD patients and should be recognized as a useful diagnostic factor in PD.

Aged↗
PubMed1996

The female 'insulin advantage' in a biracial cohort: results from the Miami Community Health Study.

OBJECTIVE: To determine the extent to which gender differences in the rate of insulin-mediated glucose disposal are influenced by differences in body fatness. DESIGN: A cross-sectional study of a biracial sample of men and women drawn from a population-based study. SUBJECTS: Twenty-five 25-44 year old residents of Dade County, FL. Twenty-five African-Americans (14 men and 11 women) and 28 white, nonHispanics (15 men and 13 women). All participants were free of diabetes mellitus (WHO Criteria). MEASUREMENTS: All persons volunteered to undergo a hyperinsulinemic euglycemic clamp procedure to determine the rate of insulin-mediated glucose disposal (insulin sensitivity, M). Several measures of body fatness were quantified and the percentage body fat determined according to published equations. RESULTS: Men and women had similar unadjusted M values. Within each gender and ethnic group M was inversely related to percentage body fat (r = -0.55 to -0.84; p < 0.05). After adjustment for percentage body fat, women were more insulin sensitive than men (10.1 vs 5.1 mg/kg/min among African-Americans and 10.1 vs 6.9 mg/kg/min among white, nonHispanics; p < 0.05 for each). When M was expressed per unit of fat free mass, women were still significantly more insulin sensitive than men (p < 0.05 for each ethnic group). In multivariate analyses, gender and percentage body fat were independently related to M in both ethnic groups accounting for 70% of the variance among African-American participants and 34% of the variance among white nonHispanic participants. CONCLUSION: The similar M values between men and women despite the higher percent body fat among women indicate that women are more insulin sensitive in muscle tissue than men. This was substantiated when M was normalized for fat free mass. This 'insulin advantage' may be related to the lower risk of coronary disease experienced by women and the loss of this advantage may in part underlie the stronger deleterious effects of diabetes that women suffer.

Adipose Tissue↗
PubMed1995

On the sample size for one-sided equivalence of sensitivities based upon McNemar's test.

In this paper we formalize the problem of testing the one-sided equivalence in the sensitivities of two medical diagnostic tests under a matched-pair study design. We derive conditional and unconditional sample size formulae which are decreasing functions of the probability of being diagnosed by both tests. We calculate upper boundary and midpoint sample sizes. Results of a Monte Carlo simulation study that compares the proposed sample size formulae with that of Lachenbruch suggest that our midpoint conditional sample size is the best choice to obtain the desired power for the type of equivalence studies discussed in the paper.

Binomial Distribution↗
PubMed1995

Assessment of the Vital Signs Quality of Life Questionnaire in three studies on hypertension.

The Vital Signs Quality of Life Questionnaire is a patient survey developed to assess the effects of treatment on 25 variables associated with a sense of well-being and perceptions of general health, mental functioning and social performance. Data collected from this questionnaire in three studies on hypertension were analysed and are presented here. In study 1, low-dose verapamil significantly reduced office and ambulatory diastolic (DBP) and systolic (SBP) blood pressure (P < 0.01) in patients with mild hypertension. In study 2, verapamil and nifedipine significantly and similarly reduced office DBP and SBP in patients with mild to moderate hypertension. In study 3, significantly greater reductions in ambulatory DBP and SBP were observed with verapamil compared with placebo (P < 0.01) in elderly patients with mild to moderate hypertension. Reported adverse experiences were not different from those known to be associated with the study drugs. There was significant improvement in the intensity of quality of life (QOL) variables (P = 0.03) and in the total (sum of frequency and intensity) QOL score (P = 0.02) following treatment in study 1. In study 2, there were no significant changes in QOL scores following treatment with either verapamil or nifedipine. In study 3, QOL scores remained statistically unchanged for both treatment groups; however, there was a trend toward improvement with verapamil and worsening with pacebo. Taken together, the data show no negative effects of verapamil on QOL, even though verapamil demonstrated significant anti-hypertensive effectiveness. The questionnaire displayed a high level reliability, as measured by Cronbach's alpha (0.91 for both frequency and intensity).

Adult↗
PubMed1995

South Florida Program on Aging and Health. Assessing the prevalence of Alzheimer's disease in three ethnic groups.

The South Florida Program on Aging and Health was initiated in 1992 with the aim to assess physical and mental health of the elderly in Dade County and provide a basis for public health policy. This report describes the methodology applied in the study and preliminary screening results in a probability sample of 2,400 African American, Cuban American and white non-Hispanic American elderly men and women. Of 2,013 participants screened by May 1995, 11.5% had cognitive impairment. An increase in prevalence from 4-7% to 25-36% with advancing age was found among men and women of each group, from the youngest (65-74) to the oldest (85+ years). Male and female prevalences were similar but vary by ethnic group and age.

Black or African American↗
PubMed1992

A pilot study of a new ELISA test for ciguatoxin in humans.

The major impediment to the thorough study of Ciguatera in human populations has been the lack of definitive diagnostic ability. However, recently an ELISA test was developed which can diagnose Ciguatera qualitatively and quantitatively in human fluids, as well as in contaminated fish tissue. This study proposes to evaluate this new ELISA test in human subjects with the clinical diagnoses of acute and chronic Ciguatera Poisoning. The contaminated fish from exposed subjects, and the blood and urine of exposed and controls, will be examined using the new ELISA. The ELISA performance will be compared to traditional bioassays for the fish testing. In addition, a distinct diagnostic profile will be developed using serial questionnaires, physical examinations, and nerve conduction tests. Ultimately this ELISA test can be used not only in establishing the correct diagnosis of Ciguatera Poisoning, but also in the treatment and clinical prognosis, and in epidemiologic studies of Ciguatera Poisoning in human populations. We hope that this protocol will serve as a model for the study of the effects of other marine toxins on human populations.

Adult↗
PubMed1991

Oncologists' reluctance to accrue patients onto clinical trials: an Illinois Cancer Center study.

Clinical trials are recognized as the standard of care for the cancer patient, and the randomized, controlled trial represents the most definitive method to determine the effectiveness or ineffectiveness of a cancer treatment. However, less than 3% of all eligible patients enter a clinical trial. Of the 437 physician members of the Illinois Cancer Center (ICC), 244 responded to a survey designed to determine factors that present a significant barrier to entering patients on clinical trials. Rigid protocol design was the primary deterrent to accrual, especially for medical oncologists. Surgeons, radiation oncologists, and medical oncologists differed with respect to several factors, including willingness to seek a clinical trial, tendency to treat patients off study, quality-of-life issues, and the belief that trials were too excessive in time commitment (P less than .05). Compared with hospital-based physicians, community oncologists had fewer patients on trial, were more likely to enter patients on the basis of age, and were more concerned about aspects of informed consent and the financial burden of a trial (P less than .01). One third of the physicians never pursued a clinical trial because of conflict with the priorities of individual care and excessive follow-up time. Fourteen percent indicated that they discouraged patients from participating in a clinical trial due to the risk of a patient receiving a placebo and patient follow-up requirements (P less than .05). Subgroups of physicians differ in their reluctance to accrue patients, and there are clusters of beliefs expressed by physicians concerning their clinical trial activity. Current conduct of clinical trials needs to be reassessed, and intervention studies are required to determine the best methodology to alter physician reluctance to pursue clinical trials.

Attitude of Health Personnel↗
PubMed1988

Epidemiology of premenstrual symptoms in a nonclinical sample. I. Prevalence, natural history and help-seeking behavior.

A stratified sample of 996 nursing school graduates from 1963 to 1984 was surveyed by mail regarding menstrual cycle characteristics. The 730 respondents reported an 87% overall lifetime prevalence of premenstrual symptoms. When the symptoms were categorized according to severity, only 3.2% of the respondents reported severe symptoms. Symptomatic women used diet change (24.6%), exercise (41.8%) and vitamins (18.9%) as self-help measures. Seventeen percent sought advice from a physician. Drug use was common; 22% were using a drug for symptoms at the time of the survey. Despite the common use of treatment, few women reported a significant work impairment. These findings support the conclusion that premenstrual symptoms are common but do not usually interfere with functioning.

Adult↗
PubMed1986

Ultrasound characterization of acute myocardial ischemia by quantitative texture analysis.

In this study we tested the efficacy of quantitative texture analysis in the identification of acute myocardial ischemia using an ultrasound data acquisition system that digitizes and stores echocardiographic data in polar format. In nine closed-chest dogs, data were acquired before and after coronary occlusion using a 2.4 MHz echocardiographic system. Regions of interest were analyzed at end-diastole and end-systole from the ischemic area and normal area at the same depth of field. Ultrasound data were evaluated using previously reported quantitative gray level texture measures. After occlusion, texture changes indicative of ischemia were found in systolic images. The directional component of the data analysis was important; analysis in the azimuthal direction was more accurate than in the axial direction. Six texture measures exhibited significant changes in the ischemic region from control to occlusion when analyzing data in the azimuthal direction. One false positive result occurred (significant texture change in the normal region from control to occlusion) in the azimuthal direction. Several false positive alterations in the normal regions from control to occlusion were found when the texture was evaluated in the axial direction. For accurate assessment of ischemic changes, preocclusion image data were required. We conclude that quantitative echocardiographic texture analysis using polar format data can identify subtle changes in myocardial texture such as that due to acute ischemia, using data acquired through the chest wall.

Acute Disease↗