Search PubMed⌕ Search

Biomedical subjects

R B Wallace

Publications and source records attributed to R B Wallace.

At least 145 records · Page 8Linked to original sources
PubMed1992

Light to moderate alcohol consumption and mortality in the elderly.

OBJECTIVE: To determine whether there is a relationship of low to moderate alcohol consumption with cardiovascular mortality in the elderly. DESIGN: Prospective cohort studies with 5-year mortality follow-up. SETTING: Three populations of community-dwelling elders. PARTICIPANTS: Population-based cohorts of men and women, aged 65 or older, in three populations. Subjects with prior myocardial infarction, stroke, or cancer, as well as those lacking alcohol consumption data, were excluded from statistical analyses leaving 2,694 subjects in East Boston, Massachusetts, 2,293 subjects in Iowa, and 1,904 subjects in New Haven, Connecticut. MAIN OUTCOME MEASUREMENTS: Alcohol consumption, total mortality, cardiovascular mortality, and cancer mortality. RESULTS: Low to moderate alcohol consumption was associated with statistically significant lowered total as well as cardiovascular mortality in East Boston and New Haven. The relative risks of total mortality for low to moderate consumers of alcohol compared to those consuming no alcohol in the previous year were 0.7 (95% CI 0.6-0.8) in East Boston and 0.6 (95% CI 0.5-0.8) in New Haven. For cardiovascular mortality, the RRs were 0.6 in East Boston and 0.5 in New Haven (95% CI's exclude null). These results persisted after control for potential confounding variables. In Iowa, there were no significant differences in total or cardiovascular mortality according to alcohol consumption patterns. For cancer mortality, there were no significant associations with alcohol consumption in any of the three populations. CONCLUSIONS: These data suggest that the relationship of low to moderate alcohol consumption with reduced total and cardiovascular mortality, which are well documented in middle age, also occur in older populations.

Activities of Daily Living↗
PubMed1992

Anemia and hemoglobin levels in older persons: relationship with age, gender, and health status.

OBJECTIVE: To determine the relationship of hemoglobin levels and anemia with age and health status in older adults. DESIGN: Survey. SETTING: Community. PARTICIPANTS AND METHODS: Hematologic tests were obtained from 3,946 adults aged greater than or equal to 71 years in three communities (East Boston, MA; Iowa and Washington counties, IA; and New Haven, CT). RESULTS: Hemoglobin level was inversely associated with age, although this was more pronounced in men than in women. The proportion anemic was equal for men and women aged 71-74 years (8.6%) and increased differentially with age, reaching 41% and 21% for men and women aged greater than or equal to 90 years, respectively. Hemoglobin and anemia were independently associated with age, race, body-mass index, smoking, cancer, hospitalization, renal insufficiency, and hypoalbuminemia. The adjusted relative odds of anemia for a 5-year increase in age was 1.5 (95% confidence interval [CI] 1.3-1.8) for men and 1.2 (95% CI 1.1-1.4) for women. CONCLUSIONS: Age is significantly associated with both hemoglobin levels and anemia, with a stronger effect in men compared with women, even after simultaneously adjusting for demographic characteristics and health status. The decline of hemoglobin and concomitant increased anemia with age is not necessarily a result of "normal aging" so the detection of anemia in an older person should prompt appropriate clinical attention.

Activities of Daily Living↗
PubMed1992

Impact of surgical relief of outflow obstruction on thallium perfusion abnormalities in hypertrophic cardiomyopathy.

BACKGROUND: To assess the impact of surgical relief of left ventricular outflow obstruction on myocardial perfusion abnormalities in patients with obstructive hypertrophic cardiomyopathy, 20 symptomatic patients who underwent a septal myectomy or mitral valve replacement were studied with assessment of myocardial perfusion during exercise by 201Tl emission computed tomography before and 6 months after surgery. METHODS AND RESULTS: Before surgery, 15 patients had myocardial perfusion defects during exercise that completely normalized at rest, one patient had both reversible and fixed perfusion defects, two patients had fixed defects only, and two patients had normal exercise and rest thallium scans. After surgical relief of left ventricular outflow obstruction (basal gradient reduced from 62 +/- 40 to 7 +/- 12 mm Hg, p less than 0.001; peak provokable gradient reduced from 131 +/- 27 to 49 +/- 36 mm Hg, p less than 0.001), repeat exercise thallium studies showed complete normalization of perfusion defects in 11 patients, including the two patients with fixed defects alone before surgery, and improvement in the magnitude and distribution of perfusion defects in five additional patients. This was associated with a significant reduction in the number of patients with reversible regional defects (five patients compared with 13 patients before surgery, p = 0.026) and of patients with endocardial hypoperfusion (four patients compared with 12 patients before surgery, p = 0.024). Furthermore, increased lung uptake of thallium was noted in five patients after surgery, compared with 12 patients before surgery (p = 0.055). Only two patients with reversible perfusion defects before surgery had unchanged postoperative studies. However, four patients acquired new fixed defects as a consequence of surgery, and two of these four had the greatest severity and distribution of left ventricular hypertrophy by echocardiography. These four patients experienced a substantially greater decrease in ejection fraction (-26 +/- 15%) after surgery than the remaining patients (-3 +/- 14%, p less than 0.01). CONCLUSIONS: Surgical relief of left ventricular outflow obstruction results in normalization or improvement of myocardial perfusion in the majority of patients with reversible and fixed perfusion defects by 201Tl scintigraphy. However, surgery may result in myocardial injury and scarring, with consequent decreased left ventricular ejection fraction in some patients.

Cardiac Catheterization↗
PubMed1992

A geriatric and gerontologic perspective on the effects of medical conditions on older drivers: discussion of Waller.

In discussing Waller's paper, we build on his review of medical conditions and the risk of motor vehicle accidents (MVAs) using principles derived from geriatrics, gerontology, and health services research. Three approaches are suggested. The medical model uses discrete diseases as risk factors, but despite its utility and appeal, this model does not sufficiently characterize health and functional status to be the sole approach, and future investigative efforts should at least consider severity of illness concepts. The functional status model emphasizes a functional and physiological approach to health status, but despite its successful application in geriatric assessment and its investigative promise, functional status can be difficult to measure and has not been validated in relation to MVA risk. Finally we consider a behavioral model and within that framework discuss the relation of depressive and other emotional illnesses as well as social vitality to driving patterns and MVA occurrence.

Accidents, Traffic↗
PubMed1992

The risk of nursing home admission in three communities.

Beginning in 1982, the 3-year incidence of nursing home admission was determined for community-dwelling residents aged 65 and over in East Boston, Massachusetts (4%); New Haven, Connecticut (9%); and Iowa and Washington Counties, Iowa (12%). A common methodology was used to collect baseline risk factor and follow-up data on nursing home admissions among persons in each community as part of the National Institute on Aging's Established Populations for Epidemiologic Studies of the Elderly. A multivariate logistic regression model of baseline risk factors that included the participant's age, race, sex, history of prior admission, ADL limitations, cognitive function, living arrangements, and level of income predicted 80% of the users in each community.

Aged↗
PubMed1992

Health status of older male prisoners: a comprehensive survey.

Although prison populations remain predominantly young, the number of older inmates in state and federal correctional facilities has been increasing. This report describes the results of a health survey of 119 male inmates 50 years of age and older residing in Iowa state correctional facilities. Subject's disease history included hypertension (40%), myocardial infarction (19%), and emphysema (18%). Most participants (97%) had missing teeth, 42% had gross physical functional impairments, and 70% smoked cigarettes. These findings have implications for health care provision and release planning.

Activities of Daily Living↗
PubMed1992

Predictors of smoking cessation and relapse in older adults.

We examined longitudinal changes in smoking behavior among older adults in three community cohorts of the Established Populations for Epidemiologic Studies of the Elderly. Smoking prevalence declined from 15% at baseline to 9% during 6 years of follow-up. Annual smoking cessation and relapse rates were 10% and less than 1%, respectively. Interval diagnosis of myocardial infarction, stroke, or cancer increased subsequent smoking cessation but not relapse. Although smoking cessation around diagnosis is increased, primary prevention could yield greater benefits.

Aged↗
PubMed1992

Epidemiology and aging: how gerontology has changed noncommunicable disease epidemiology in the United States of America.

Epidemiology is a continuously evolving discipline that has been greatly enriched by addressing the health problems of the elderly. In the United States of America, this has resulted in a large national data resource of functional and health measures on older populations, heretofore not available. In this article, suggestions are made for research priorities in the next 10 years in the epidemiological study of the elderly. They include: (i) a special emphasis on enhancing analytical methods, particularly for complex longitudinal data; (ii) an effort to understand the impact of the physiochemical environment on older persons, both in the household and workplace setting; (iii) the identification of new ways to determine early life exposures among older persons, so that hypotheses about early influences on aging processes can be tested; and (iv) a general effort to include function status and other geriatric measures as a routine part of the clinical record, so that secondary research on such records can be more conveniently performed.

Aged↗
PubMed1992

Platelet activating factor antagonist enhances lung preservation in a canine model of single lung allotransplantation.

Optimal techniques for lung preservation are yet to be defined. Platelet activating factor is a phospholipid released by a variety of cells and produces pulmonary abnormalities similar to posttransplantation pulmonary dysfunction. We investigated the strength of the effect of the platelet activating factor antagonist BN 52021 as compared with that of deferoxamine, an iron chelator previously shown to improve lung preservation. Differential lung function and pulmonary hemodynamics were used to assess preservation after a 6-hour period of cold ischemic storage in a modified canine model of left lung allotransplantation. Thirty size- and weight-matched mongrel male dogs were used for 15 transplant procedures randomized to one of three preservation techniques. The University of Wisconsin solution was used as the basic flush solution for all experimental animals. BN 52021 was added to the flush solution in one group (10 mg/kg, n = 5) and deferoxime in another group (10 mg/kg, n = 5). No additives were used for the control animals (n = 5). BN 52021 and deferoxime were administered to respective donor animals 30 minutes before organ harvesting (10 mg/kg) and to recipient animals 30 minutes before reperfusion (10 mg/kg). The pulmonary artery flush solution was administered (40 ml/kg) over 4 minutes. Recipient animals received double-lumen endotracheal tubes and were monitored with balloon-tipped, flow-directed catheters in both pulmonary arteries and dual-angle ultrasonic flow probes around each pulmonary artery. Solid-state high-fidelity micromanometers were used to measure pressures in the pulmonary artery, the left atrium, and the left ventricle. Systemic arterial, right and left pulmonary venous, and mixed venous blood samples were analyzed at 1, 2, 4, and 6 hours after transplantation. Pulmonary venous oxygen tension of the transplanted lung for the control group was 202 +/- 81 mm Hg versus 282 +/- 53 mm Hg for the BN 52021 group 6 hours after transplantation (p less than 0.05). Pulmonary vascular resistance of the transplanted lung for the control group was 319 +/- 54 dynes.sec.cm-5 versus 149 +/- 71 dynes.sec.cm-5 for the BN 52021 group (p less than 0.05). Proton magnetic resonance spectroscopy was performed on segments of upper and lower lobes of the native and transplanted lung from recipient animals to determine total lung water content. The BN 52021 group had a total lung water content of 57.3% as compared with 51.9% for the deferoxime group (p = not significant) and 88.6% for the control group (p less than 0.05).(ABSTRACT TRUNCATED AT 400 WORDS)

Adenosine↗
PubMed1992

Donor heart valves: electron microscopic and morphometric assessment of cellular injury induced by warm ischemia.

Cryopreserved allograft valves are increasingly being used as valvular replacements. Leaflet fibroblast viability has been suggested to influence clinical durability. The warm ischemic time is thought to be a critical determinant of this cell viability. The purpose of this study was to apply quantitative morphometric methods to characterize, by transmission electron microscopy, valvular cellular injury resulting from progressive warm ischemic time. Porcine aortic valves were harvested with a spectrum of warm ischemic times (40 minutes and 2, 6, 12, 24, and 36 hours; five valves per warm ischemic time; n = 30) and processed by standard electron microscopic methods. To ensure randomized tissue selection within each warm ischemic time interval, we randomly selected one thin section from each leaflet. The first ten cells in each thin section were photographed and cellular injury was assessed (cell disruption, dilation of endoplasmic reticulum, cytoplasmic edema, nuclear and mitochondrial changes). Nine hundred micrographs have been analyzed by Cochran-Mantel-Haenszel statistics to determine if a significant association between warm ischemic time and cellular injury exists. Our findings indicate a significant association between reversible cell injury through 24 hours of warm ischemic injury (p less than 0.0001). Furthermore, a significant association between irreversible cell injury and progressive warm ischemia through 36 hours was also found. These findings indicate that the ischemic interval after donor death is associated with progressive leaflet cell injury. Cellular damage begins shortly after donor death and continues incrementally throughout 36 hours. After 2 hours of warm ischemic injury 37% of the cells had morphologic evidence of injury. After 6 hours of warm ischemic injury the number of injured cells increased to 73%. By 36 hours 22% of the cells appeared normal. Irreversible cell injury increases with prolonged ischemia and becomes quantitatively impressive at 24 hours, by which time 26% of cells are so affected. Conversely, some cells are resistant to irreversible injury for a prolonged ischemic interval.

Animals↗
PubMed1991

The accuracy of self-reported hearing loss in women aged 60-85 years.

The accuracy of self-report in identifying individuals with hearing impairment was evaluated in 1988 in 267 women from rural Iowa. Using pure-tone threshold audiometry as the standard, self-reported hearing loss was a sensitive and specific indicator of measured losses of 40 decibel hearing level for pure-tone averages of either 1,000 and 2,000 Hz or 1,000, 2,000, 3,000 and 4,000 Hz (sensitivities, 90% and 84%; specificities, 71% and 75%, respectively). Predictive values positive were low (28% and 42%) in this population where hearing loss prevalence was 11-18%, but would be increased to acceptable levels in populations with a prevalence of approximately 30%.

Aged↗
PubMed1991

Blood pressure and mortality risk in the elderly.

Blood pressure was assessed between 1981 and 1983 in all persons over age 65 years in three communities (East Boston, Massachusetts; New Haven, Connecticut; and Iowa and Washington countries, Iowa), and cause-specific mortality was monitored annually over the subsequent 5 years as part of the National Institute on Aging-sponsored Established Populations for Epidemiologic Studies of the Elderly. Each community had 80% or more participation: in East Boston, 3,809 persons with 903 deaths, in New Haven, 2,812 persons with 804 deaths, and in Iowa, 3,673 persons with 763 deaths. At 2 years, odds of death from all causes were higher in the low (less than 130 mmHg) than the middle (130-159 mmHg) systolic blood pressure group for persons aged 65-79 years in all three populations. By 5 years, cardiovascular death increased with increasing systolic pressure in all three communities and reached significance in Iowa. Cancer death was highest in the low systolic pressure stratum in all three centers. All-cause, cardiovascular death, and cancer mortality was highest in the low (less than 75 mmHg) diastolic blood pressure group in East Boston, even at 5 years. Blood pressures obtained 9 years earlier in 2,079 (68%) of the East Boston participants showed a significantly higher risk of cardiovascular death with increasing systolic pressure and no relation between diastolic pressure and mortality risk. In the elderly, excess mortality at lower levels of blood pressure during early follow-up may in part be due to the effects of illness and disability present at baseline. This may obscure the usual rise in mortality with increasing systolic pressure. There is no consistent relation between diastolic pressure and mortality.

Aged↗
PubMed1991

Smoking and mortality among older men and women in three communities.

BACKGROUND: Although cigarette smoking is the leading avoidable cause of premature death in middle age, some have claimed that no association is present among older persons. METHODS: We prospectively examined the relation of cigarette-smoking habits with mortality from all causes, cardiovascular causes, and cancer among 7178 persons 65 years of age or older without a history of myocardial infarction, stroke, or cancer who lived in one of three communities: East Boston, Massachusetts; Iowa and Washington counties, Iowa; and New Haven, Connecticut. At the time of the initial interview, prevalence rates of smoking in the three communities ranged from 5.2 to 17.8 percent among women and from 14.2 to 25.8 percent among men. During five years of follow-up there were 1442 deaths, 729 due to cardiovascular disease and 316 due to cancer. RESULTS: In both sexes, rates of total mortality among current smokers were twice what they were among participants who had never smoked. Relative risks, as adjusted for age and community, were 2.1 among the men (95 percent confidence interval, 1.7 to 2.7) and 1.8 among the women (95 percent confidence interval, 1.4 to 2.4). Current smokers had higher rates of cardiovascular mortality than those who had never smoked (as adjusted for age and community, the relative risk was 2.0 [95 percent confidence interval, 1.4 to 2.9] among the men and 1.6 [95 percent confidence interval, 1.1 to 2.3] among the women), as well as increased rates of cancer mortality (relative risk, 2.4 [95 percent confidence interval, 1.4 to 4.1] among the men and 2.4 [95 percent confidence interval, 1.4 to 3.9] among the women). In both sexes, former smokers had rates of cardiovascular mortality similar to those of the participants who had never smoked, regardless of age at cessation, whereas the rates for all cancers, as well as smoking-related cancers, remained elevated among men who had once smoked. CONCLUSIONS: Our prospective findings indicate that the mortality hazards of smoking extend well into later life, and suggest that cessation will continue to improve life expectancy in older people.

Age Factors↗
PubMed1991

A prospective study of bone mineral content and fracture in communities with differential fluoride exposure.

In 1983/1984, a study of bone mass and fractures was begun in 827 women aged 20-80 years in three rural Iowa communities selected for the fluoride and calcium content of their community water supplies. The control community's water had a calcium content of 67 mg/liter and a fluoride content of 1 mg/liter. The higher-calcium community had water with a calcium content of 375 mg/liter and a fluoride content of 1 mg/liter. The higher-fluoride community's water had 15 mg/liter of calcium and 4 mg/liter of fluoride naturally occurring. In 1988/1989, a follow-up study characterized the 684 women still living and available for study. Residence in the higher-fluoride community was associated with a significantly lower radial bone mass in premenopausal and postmenopausal women, an increased rate of radial bone mass loss in premenopausal women, and significantly more fractures among postmenopausal women. There was no difference in the 5-year relative risk of any fracture in the higher-calcium community versus the control community; however, the relative risk was 2.1 (95% confidence interval (CI) 1.0-4.4) in women in the higher-fluoride community compared with women in the control community. There was no difference in the 5-year risk of wrist, spine, or hip fracture in the higher-calcium community versus the control community; however, the 5-year relative risk for women in the higher-fluoride community, compared with women in the control community, was 2.2 (95% CI 1.1-4.7). Estimates of risk were adjusted for age and body size.

Adult↗
PubMed1991

Amplification by the polymerase chain reaction of hypervariable regions of the human genome for evaluation of chimerism after bone marrow transplantation.

We combined the polymerase chain reaction (PCR) with oligonucleotide hybridization as a novel and sensitive technique to evaluate posttransplant chimerism. Specific oligonucleotides for hybridization were synthesized homologous to tandemly repetitive core sequences of regions with a variable number of tandem repeats (VNTRs). Polymorphisms at such loci result from allelic differences in the number of repeats. Primers flanking the repeat region of each of the corresponding VNTRs were used for amplification. Recipient and donor pretransplant DNA and recipient posttransplant DNA were amplified. The resultant fragments were analyzed after gel electrophoresis either by hybridization in-gel or after Southern transfer. To confirm our findings, we also performed standard assays of restriction fragment length polymorphisms (RFLPs). Evaluation of 13 selected cases indicated mixed chimerism (4), complete chimerism (5), recurrence of leukemia (2), and endogenous repopulation of hematopoiesis (2) after marrow transplantation. Sensitivity of the method was determined by mixing various proportions of recipient and donor DNA; the limit of detection of the minor component in a mixture was 0.1%. PCR data correlated with RFLP data in all cases except two in which PCR proved more sensitive than RFLP. PCR amplification of VNTRs combined with oligonucleotide hybridization is a novel technique for documenting posttransplant chimerism and has advantages over RFLP analysis: high sensitivity, use of small amounts of DNA (250 ng), ease of preparation of DNA, elimination of need for restriction enzymes, and the ability to complete studies in 2 days.

Base Sequence↗
PubMed1991

Increased incidence of diabetes mellitus in relation to abdominal adiposity in older women.

The relationship between body fat distribution, measured by the ratio of waist-to-hip circumferences (WHR), and the 2 year incidence of diabetes mellitus was examined in a cohort of 41,837 women aged 55-69 years. The 399 women who reported the new onset of diabetes had a significantly greater mean body mass index (kg/m2) and WHR than non-cases. After adjustment for body mass index (BMI), age and education level using multivariate logistic regression, WHR was a significant independent predictor of diabetes in a dose-response fashion. Cases were 4.6 times (95% CI = 3.8, 5.6) more likely than non-cases to be in the upper tertile of WHR and 2.2 times (95% CI = 1.8, 2.7) more likely to be in the middle tertile. Women in the highest tertiles of both WHR and BMI had a 14.4-fold (95% CI = 9.5, 21.9) higher risk of diabetes than women in the lowest tertiles. These results demonstrate that increased abdominal adiposity is a significant independent risk factor for the development of diabetes mellitus in older women.

Aged↗