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Biomedical subjects

L M Gerber

Publications and source records attributed to L M Gerber.

At least 19 recordsLinked to original sources
PubMed2005

Association of leptin levels with obesity and blood pressure: possible common genetic variation.

OBJECTIVE: To ascertain the extent to which relationships between obesity (OB) and blood pressure (BP) can be explained by an individual's leptin plasma levels. DESIGN: Pedigree-based cross-sectional study in an apparently healthy population of European origin. SUBJECTS: The study sample is comprised of 90 nuclear and more complex families totaling 210 male and 213 female subjects aged 18-75 y, randomly recruited in Bashkorstan Autonomic region, Russia. MEASUREMENTS: Various fatness and fat distribution traits (including nine circumferences (CRCs), and eight skinfolds (CKFs) by anthropometry), blood pressure, and plasma leptin levels (by ELISA kits). RESULTS: Adjustment for circulating leptin led to attenuation of the magnitude of correlations between OB and BP, regardless of trait pair and sex cohort. Some of these correlations became statistically nonsignificant. All familial effects were gone, and heritability estimates became virtually zero after adjustment of each of the OB traits and systolic blood pressure (SBP) in offspring for leptin values in parents. CONCLUSION: BP and OB covariation is substantially mediated by circulating leptin levels. As a result, body fat has only a weak independent effect on BP variation after adjustment for leptin levels. Our findings also strongly suggest that genetic variation in body mass index, SKFs, and even body CRCs, as well as of SBP is due to genetic variation of leptin. Genetic variation of diastolic blood pressure in the present sample, however, shared very little with that of leptin.

Adolescent↗
PubMed2001

Low-dose alpha/beta blockade in the treatment of essential hypertension.

Despite the recent emphasis on combination drug therapy for hypertension, little attention has been given to alpha/beta blockade using agents other than labetalol. The purpose of this study was to 1) compare the efficacy of low-dose alpha/beta blockade using doxazosin + betaxolol, versus monotherapy with an angiotensin converting enzyme inhibitor (quinapril) and a diuretic (hydrochlorothiazide [HCTZ]), and 2) assess the efficacy of low-dose doxazosin. In a crossover study, 21 hypertensive subjects were treated for 3 weeks each with HCTZ, 12.5 to 25 mg/day, quinapril, 10 to 40 mg/day, and a combination of doxazosin, 1 to 4 mg + betaxolol, 5 to 10 mg daily. Doses were titrated to achieve a systolic pressure <130 mm Hg, as assessed by self-recorded home measurements. Home blood pressure decreased 11.5/7.5 mm Hg after HCTZ, 12.9/8.8 mm Hg after quinapril, and 21.2/16.5 mm Hg after doxazosin + betaxolol (P < .001/< .001 v HCTZ and P < .002/< .001 v quinapril). The target systolic pressure was achieved by 33%, 43%, and 71% of subjects, respectively (P = .04 v HCTZ, and .03 v quinapril). Among the 8 subjects in whom doxazosin dosage was increased to the maximum of 4 mg, the mean blood pressure achieved at 4 mg did not differ from that achieved at 2 mg (136/87 v 136/88 mm Hg). We conclude that oral alpha/beta blockade is superior to monotherapy with an angiotensin converting enzyme inhibitor or a diuretic and that maximal or near maximal efficacy can be achieved at a 2-mg dose of doxazosin. Low-dose oral alpha/beta blockade merits greater consideration in the drug therapy of essential hypertension.

Adrenergic alpha-Antagonists↗
PubMed2001

Association of urinary albumin concentration with casual and ambulatory blood pressure: a similar relationship in normotensive and hypertensive subjects.

BACKGROUND: The urinary albumin level has been found to be positively correlated with blood pressure in hypertensive patients. To our knowledge, this relationship has not been evaluated in normotensive subjects and compared with that in hypertensives using casual and ambulatory blood pressure measurements. METHODS: In this cross-sectional study, a cohort of 234 normotensive and hypertensive participants wore an ambulatory blood pressure monitor for 24 h, standardized casual blood pressure measurements being taken. The urinary albumin concentration was determined by the dipstick Micral Test. The bivariate and multivariate relationship between urinary albumin concentration and demographic and blood pressure measures was investigated using correlational and regression analyses. RESULTS: The prevalence of microalbuminuria was significantly greater in the hypertensive than normotensive participants. The urinary albumin concentration was positively associated with both casual and ambulatory measures of blood pressure in both the normotensive and hypertensive subsamples, stronger correlations being found for systolic blood pressure. The relationship between systolic blood pressure and urinary albumin concentration was similar in the normotensive and hypertensive subsamples. CONCLUSIONS: These findings confirm earlier reports of the greater prevalence of microalbuminuria in patients with hypertension than in normotensive participants, as well as those reporting a continuous relationship in hypertensive participants. This study extends prior research to a normotensive subsample, in whom a similar relationship of blood pressure to microalbuminuria, using both ambulatory and casual measures of blood pressure, was found. Future research should investigate the causal direction of this relationship.

Adult↗
PubMed2001

Familial factors of blood pressure and adiposity covariation.

In the present study, we used the maximum likelihood approach as implemented by variance analysis and attempted to quantify genetic and environmental components of variance in systolic (SBP) and diastolic (DBP) blood pressure in 514 individuals who belonged to a total of 135 nuclear families of Chuvasha, Russia, ethnic origin. The extent to which these interindividual differences depend on age, gender, body mass index (BMI) and other anthropometric measurements was investigated. Major findings include the following. (1) The variation in both SBP and DBP was significantly affected by genetic factors (h(2)(SBP)=0.51+/-0.13, h(2)(DBP)=0.20+/-0.09), shared household environment, and age. These effects were stronger with respect to SBP, which also showed significant gender differences in baseline values and rate of SBP increase with age. (2) Genetic and common household factors, as well as undetected residual effects, were not completely independent. The respective 3 facets of correlation between SBP and DBP were significant: 0.66+/-0.10, 0.76+/-0.11, and 0.55+/-0.14. (3) SBP and DBP each showed significant phenotypic correlations with BMI and anthropometric factors. These correlations had a substantial genetic component but were not equal for SBP and DBP. SBP showed the highest genetic correlation with arm circumference (r(G)=0.63), whereas for DBP, this was found with hip skinfold (r(G=)0.88). (4) Bivariate heritability estimates, as well as adjustment of BP measurements for BMI and selected anthropometrics, indicated that DBP likely does not have independent genetic heritability. The residual genetic variance of adjusted SBP remained significant, although substantially lower in comparison with the nonadjusted h(2).

Adipose Tissue↗
PubMed1999

Effect of body weight changes on changes in ambulatory and standardized non-physician blood pressures over three years.

PURPOSE: This study examines the relationship of changes in body mass index (BMI) to changes in measures of both casual and ambulatory blood pressures over three years. METHODS: In this prospective study of men aged 30-60 years, a cohort of 198 participants was followed for three years. Height, weight, demographic characteristics, and casual and ambulatory measures of blood pressure (BP) were obtained at baseline and 3-year follow-up. RESULTS: Change in BMI was significantly associated with change in all ambulatory (awake, work, home, and sleep) and casual systolic and diastolic blood pressures. After controlling for age and race/ethnicity, the association remained significant for nine of the twelve BP change measures. Further tests show that the effect of a change in BMI on BP change does not vary across the six systolic blood pressures or across the six diastolic measures. An average-height man gaining 5 kg (11 pounds) typically exhibited a 2.5 mm Hg increase in systolic and a 1.8 mm Hg increase in diastolic casual and ambulatory BPs. There is no evidence that changes in BP were associated with age, race/ethnicity (blacks vs. Hispanics vs. whites), or the average of the baseline and follow-up levels of BMI. In addition, the impact of weight gain is similar in magnitude, but in the opposite direction, to that of weight loss. CONCLUSIONS: Changes in BMI over three years predict changes in ambulatory and standardized non-physician BPs. These changes in BP are not related to average BMI level or age.

Adult↗
PubMed1999

The nutrient-toxin dosage continuum in human evolution and modern health.

Recent findings support the long-recognized principle that nutritive and toxic effects of an ingested material depend not only on its nature but very much on its quantity. The well known observation that essential nutrients can be toxic at high dosages suggests that the same reversal of effect may be true of many substances that could be beneficial but not essential at low dosages (the phenomenon of hormesis). This has been demonstrated for many well known toxins. We suggest a mathematical model that describes these dosage effects as an expected result of the evolution of human metabolic and dietary adaptations for maximizing benefits and minimizing costs of the ingestion or other intake of any substance. Evolved mechanisms for achieving benefits may be unrelated to those for reducing costs. These evolutionary considerations suggest important consequences demonstrable by experimental or epidemiological studies. They also suggest ways in which our evolved dietary adaptations may be currently maladaptive, and individual development of taste preferences poorly calibrated by early experience in modern environments. The apparent reality of hormesis raises the possibility of counterproductive effects of current dosage recommendations and limits for nutrients and pollutants. We propose that some conceptual and factual problems are urgently in need of resolution. Fundamental to evolutionary biology is the tendency for organisms to become increasingly adapted to those environments to which they are most commonly exposed (Parsons 1990).

Adaptation, Physiological↗
PubMed1999

Relationship of body size and body mass to blood pressure: sex-specific and developmental influences.

The relationship of body mass and body fat distribution to blood pressure has been recognized for many years. This relationship has formed the basis for much additional research, including the impact of growth and developmental factors on blood pressure levels. Blood pressure in children is related to somatic growth and is tied to increases in height, skeletal maturation, and sexual maturation. Sexual and ethnic differences in blood pressure levels are already apparent during childhood and may also be related to the process of growth and sexual maturity. Body size exerts a profound influence on a variety of physiological functions, including blood pressure and the onset of sexual maturity. In general, studies have reported a strong linear relationship between height and blood pressure and between body mass and blood pressure such that tracking correlations from childhood to adulthood for both blood pressure and body mass index are significant for most sex and ethnic groups. Studies evaluating the effects of hormone replacement therapy on post-menopausal women have thus far generated results suggesting that the age-related rise of blood pressure is not due directly to hormonal changes associated with menopause. The interrelated effects of growth, maturation, body weight, and body fat are influenced by both genetic and environmental factors. Environmental influences may modify relationships established much earlier, perhaps as early as prenatally, during infancy, or during early childhood. Directions for future research and implications resulting from the complex relationship between body weight and blood pressure are discussed.

Adolescent↗
PubMed1998

Assessment of a new dipstick test in screening for microalbuminuria in patients with hypertension.

The prevalence of elevated urinary albumin levels is significantly greater in hypertensive than in normotensive subjects. To determine the sensitivity and specificity of a new dipstick test for microalbunimuria (the Micral-Test), 171 hypertensive patients were studied at a union-sponsored hypertension treatment program. Sensitivity, specificity, predictive values, and correlation coefficients between urinary albumin concentration results obtained by the Micral-Test and by nephelometry were determined in three urine samples. Sensitivity values of the Micral-Test, compared with 24-h nephelometry, were 81%, 75%, and 92% in a 24-h, overnight, and random sample, respectively. Specificity values were 89%, 90%, and 63% in the three samples, respectively. Positive predictive value ranged from 41% to 67%, whereas negative predictive value ranged from 93% to 97%. Correlation coefficients between the logarithms of albumin concentrations obtained from the three different urine specimens using nephelometry fell between 0.71 and 0.78, whereas those obtained with the Micral-Test fell between 0.49 and 0.71, and across techniques, 0.29 to 0.53 (all P < .001). Results obtained with both nephelometry and the Micral-Test using overnight and random urine collections approximated those obtained with 24-h collection. These results, coupled with the ease and convenience of both specimen collection and the Micral-Test itself, support the use of the test as a valuable screening tool for microalbuminuria in patients with hypertension.

Adult↗
PubMed1998

Impact of shift work and race/ethnicity on the diurnal rhythm of blood pressure and catecholamines.

To evaluate the effects of shift work and race/ethnicity on the diurnal rhythm of blood pressure and urinary catecholamine excretion of healthy female nurses, 37 African American women and 62 women of other races underwent ambulatory blood pressure monitor and urine collection for 24 hours that included a full work shift: day shift (n=61), evening shift (n=11), and night shift (n=27). Awake and sleep times were evaluated from subjects' diaries. Of African Americans, 79% who were working evenings or nights and 32% working day shifts were nondippers (<10% drop in systolic pressure during sleep), whereas only 29% of others working evening+night and 8% working day shifts were nondippers. Regression analyses indicated that evening+night shift workers had a 5.4 mm Hg (P<0.001) smaller drop than day shift workers, and African Americans had a 4.0 mm Hg (P<0.01) smaller drop than others. The odds of an evening+night shift worker being a nondipper were 6.1 times that of a day shift worker (P<0.001), and the odds of an African American were 7.1 times that of others (P<0.001). Total sleep time was significantly greater in the non-African American day shift workers than in the other 3 groups. After controlling for work shift and race/ethnicity, we determined that longer sleep times predicted less dipping (absolute and relative) in blood pressure. Urinary norepinephrine and epinephrine were higher during work than nonwork in both racial groups of day shift workers, but in evening+night shift workers the difference was small and in the opposite direction. These results indicate that being African American and working evening or night shifts are independent predictors of nondipper status. Higher sleep blood pressure may contribute to the known adverse effects of shift work.

Adult↗
PubMed1994

Response to the captopril test is dependent on baseline renin profile.

OBJECTIVE: To determine prospectively the relationship between the renin-sodium profile and the renin response to captopril challenge in patients with essential hypertension. DESIGN: A standard captopril test was performed in 108 uncomplicated, untreated hypertensive subjects with normal renal function and urinary sodium excretion in the range 50-240 mmol/day. The subjects were selected from a working population with a low expected prevalence of renovascular disease. METHOD: The captopril test was considered positive if the captopril-induced rise in plasma renin activity met all three criteria established by Müller et al. Patients with a positive test and those meeting only one or two of the three criteria were further investigated for renovascular hypertension by measuring renal venous renins and by digital subtraction intravenous angiography. Renin responses were analyzed according to baseline renin-sodium profile. RESULTS: Nine of 108 subjects had a false-positive captopril test result. Among the subjects with a low or normal renin-sodium profile, 1% (one of 82) had a false-positive result. In contrast, false-positive results were seen in 31% (eight of 26) of high-renin subjects. False-positive test results were not related to urinary sodium excretion or to excessive decrease in blood pressure. The magnitude of the renin response to captopril was strongly and directly related to the baseline plasma renin activity. CONCLUSION: An exaggerated renin response to captopril challenge is common in patients with high-renin essential hypertension. Therefore, in a population with a low probability of renovascular hypertension, caution is recommended in interpreting a positive test result in patients with a high baseline renin.

Adult↗
PubMed1992

Differences in urinary albumin excretion rate between normotensive and hypertensive, white and nonwhite subjects.

Eighty-one normotensive and 61 hypertensive white and nonwhite subjects were studied cross-sectionally to determine the prevalence and determinants of elevated urinary albumin levels. Twenty-four-hour urinary albumin excretion was determined by radioimmunoassay. The prevalence of elevated urinary albumin level (greater than or equal to 15 mg/24 h) was significantly greater in hypertensive than in normotensive subjects (31.1% and 8.6%). Among hypertensive subjects, a much greater proportion of whites than nonwhites had urinary albumin levels of 15 mg/24 h or greater (39.5% and 17.4%). The independent association of blood pressure with urinary albumin level was affirmed by logistic regression analyses for white normotensive and hypertensive subjects combined, and for hypertensive subjects alone. Furthermore, among hypertensive subjects, whites were five times as likely as nonwhites to have elevated urinary albumin levels. Thus, blood pressure and ethnicity were the important determinants of urinary albumin excretion among hypertensive subjects.

Adolescent↗
PubMed1990

Body fat and its distribution in relation to casual and ambulatory blood pressure.

This study was undertaken to evaluate the associations of body fat and its distribution with casual and ambulatory blood pressure in nonobese men. One hundred and thirty-five normotensive or mildly hypertensive (but untreated) men employed at three work sites were studied. Casual blood pressure was measured at the work site at initial screening and on a second occasion by a nurse. Ambulatory blood pressure was measured noninvasively for 24 hours on a workday and analyzed as work, home, and sleep blood pressure measurements. Anthropometric measurements included height, weight, and waist and hip circumferences. Blood pressure was highest while at work; home blood pressure was higher than screening blood pressure or nurse blood pressure, and sleep blood pressure was lowest. Weight and both waist and hip circumferences (but not their ratio) were all significantly correlated with screening, nurse, and sleep blood pressures but not with work or home blood pressures. Stepwise regression analysis showed that waist circumference was the best overall predictor of blood pressure. We suggest that in situations where blood pressure is the dependent variable, correlations with other variables may be closest for "basal" measures of blood pressure and may be obscured by the effects of daily activities on blood pressure.

Adipose Tissue↗
PubMed1990

Sentinel Health Events (Occupational): analysis of death certificates among residents of Nassau County, NY between 1980-82 for occupationally related causes of death.

Death certificates for residents of Nassau County, New York dying between 1980 and 1982 were examined for causes of death defined as Sentinel Health Events (Occupational) (SHE(O]. Of 16,193 deaths from all causes, 2,286 (14.1 percent) were identified as SHE(O) deaths; 142 (6.2 percent) of these were matched for occupational and/or industry, 13 (9.2 percent) of which required no further match [corrected] because the cause of death was inherently related to the occupation or industry. Malignant neoplasms of the trachea, bronchus, or lung were the most frequently occurring SHE(O), accounting for 60 percent of all SHE(O) deaths and 81 percent of matched SHE(O) deaths. The construction industry was associated with the vast majority of such deaths.

Adolescent↗
PubMed1989

Coronary care in New York City hospitals.

New York City, with six medical schools and an elaborate emergency medical system, would appear to be a locale with optimal resources for coronary care. To assess coronary care facilities and practices, a comprehensive questionnaire was prepared by a multidisciplinary committee and submitted to 72 hospitals. Seventy-nine percent (57/72) responded, including all medical school affiliated hospitals and 41 of the 45 with more than 300 beds. Twenty-nine percent (16/55) did not have a coronary care unit separate from a general intensive care unit. Thirty-three percent (18/55) of coronary care units were designed before 1970. Although 85% (46/54) of the coronary care units had a 1:2 registered nurse per patient ratio during days, only 43% (23/54) maintained this ratio at night. Central monitoring was available in all hospitals, but only 40% (21/52) indicated 24-hour continuous monitor observation. Forty-five percent (25/55) had cardiac catheterization facilities, and 43% (24/56) had an intra-aortic balloon available. Forty-six percent (26/57) of coronary care units transferred post-myocardial infarction patients to non-monitored general beds. Fifty-eight percent (31/53) offered dietary counseling to patients, and 33% (18/54) had an inpatient cardiac rehabilitation program. Thus, New York City hospitals demonstrate a marked variability in coronary care unit facilities and practices and a substantial number of hospitals deviate from published recommendations for coronary care units.

Coronary Care Units↗
PubMed1986

Antihypertensive drug therapy withdrawal in a general population.

To determine the fraction of all hypertensives who can be successfully withdrawn from antihypertensive medication, a study was conducted of a patient group originally drawn from a screened population of union members. Of 157 patients, 88 (56.1%) met preestablished blood pressure criteria for drug interruption, and 66 (75%) actually had medication withdrawn. Of these 66 patients, 69.8% and 54.5% followed up for one and two years, respectively, remained normotensive. Patients requiring reintroduction of antihypertensive therapy were distinguished from those remaining drug free by increased systolic blood pressure (141.4 +/- 13.2 vs 131.6 +/- 8.6 mm Hg) after one month. Extrapolation of the finding that 28% of the study population remained normotensive one year after drug therapy withdrawal suggests the possibility that as many as 5 million Americans currently taking antihypertensive drugs could have therapy interrupted for at least one year and thus avoid both the hazards and costs of drug therapy.

Aged↗
PubMed1985

Step-down therapy for hypertension. Results in a community-based program.

The study reported here involved a systematic attempt to withdraw medication from participants in a community-based hypertension treatment program. Sixty-six of 88 patients with well-controlled mild or moderate disease had medication withdrawn after at least six months of treatment; nonpharmacologic intervention was not employed. After one year, 44 (66.6%) remained normotensive and drug free; after two years, 33 (50.0%). Of the 29 patients still available for three-year follow-up, 15 (51.7%) were still normotensive and drug free. Withdrawal of medication was associated with correction of hypokalemia and reversal of impaired glucose tolerance. Thus, nearly one fourth of these patients, who were believed to be reasonably representative of those with mild or moderate hypertension, could discontinue drug therapy and remain normotensive for at least one year. Substantial medical and economic benefits are to be realized from wide replication of this experience.

Aged↗