Biomedical subjects

R B Wallace

Publications and source records attributed to R B Wallace.

At least 19 recordsLinked to original sources

PubMed1992

Self-reported adverse drug reactions and related resource use. A study of community-dwelling persons 65 years of age and older.

OBJECTIVE: To describe the incidence and health resource consequences of self-reported adverse drug reactions (ADRs) and their relation to self-perceived health, number of medications used, and age in a geographically based population 65 years of age and older. DESIGN: A survey of a defined population. PARTICIPANTS: Three thousand, one hundred seventy noninstitutionalized persons 65 years of age and older residing in two Iowa counties. MEASUREMENTS: Reports of ADRs (elicited using an open-ended questionnaire); names of drugs involved; descriptions of reactions and related health resource use; self-perceived health status (at the first annual follow-up); and number of medications (from the baseline interview). RESULTS: Ten percent (95% CI, 8.97 to 11.09) of respondents reported one or more ADRs. Three quarters of respondents who reported ADRs contacted a physician. Of these, half indicated that a laboratory test had been ordered, and 7% reported a hospitalization due to the reaction. Advanced age alone was associated with decreased risk in women; a similar trend in men was not statistically significant. However, persons with poorer health status and those who reported the greatest prior use of medications were most likely to report reactions. CONCLUSIONS: In this study of noninstitutionalized elderly persons, advanced age did not appear to be associated with increased risk for self-reported ADRs. We could not determine whether the decrease in ADR reports among the oldest respondents represented true diminished ADR occurrence or altered ADR detection and reporting capabilities. When projected to the elderly community-dwelling U.S. population, 2.2 million annual physician visits, 1.1 million laboratory tests, and 146,000 hospitalizations may result from ADRs.

Age Factors↗

PubMed1992

Genetic markers associated with high density lipoprotein cholesterol levels in a biracial population sample.

An explanation for the consistently documented finding of higher levels of high density lipoprotein-cholesterol in black men relative to white men was sought by comparing the frequency of restriction fragment length polymorphism markers present in blacks and in whites at the gene loci coding for the two major apolipoprotein constituents of high density lipoprotein, apolipoproteins AI and AII. The measurements were made in population-based samples of 45 to 54-year-old black (n = 190) and white (n = 370) subjects from the Minnesota Heart Survey for whom lipoprotein levels were available. The mean high density lipoprotein-cholesterol level for black men in the sample (47 +/- 1.5 mg/dl) was higher (P less than 0.05) than that for white men (42 +/- 0.9 mg/dl), while levels in women were not different between races. While the SacI and MspI markers at the apolipoprotein AI-CIII-AIV gene locus showed similar frequencies in blacks compared to whites, the degree of the linkage disequilibrium previously noted between these markers in white subjects was altered in blacks and the minor allele of the PstI marker at this locus was virtually absent in the black subjects (P less than 0.005 vs whites). For black men, there were significant associations of the M2 allele and the S2M2 haplotype at the apolipoprotein AI locus with lower high density lipoprotein-cholesterol levels. The results are consistent with the hypothesis that DNA sequence variations in the vicinity of the apolipoprotein AI-CIII-AIV gene locus are associated with the difference in high density lipoprotein-cholesterol levels between blacks and whites.

Adult↗

PubMed1992

Radial bone mineral density in pre- and perimenopausal women: a prospective study of rates and risk factors for loss.

Radial bone mineral density (BMD) of 217 white women aged 22-54 years from a single rural community was evaluated in 1984 using single-photon absorptiometry. BMD was measured at a site one-third the distance from the wrist to the elbow, a site that represents predominantly cortical bone tissue. Most of these women (181; 83%) were reexamined 5 years later. The overall average 5 year radial BMD loss was -5.6%. The average rate of loss was -4.5% for women retaining positive estrogen status at follow-up (n = 108) and -7.4% for women who were in negative estrogen status at follow-up (n = 73). Baseline radial BMD measures were highly predictive of the follow-up BMD values (r = 0.80). Women with positive estrogen status and greater baseline BMD also had less BMD change. Greater baseline BMD did not predict the amount of change in women with negative estrogen status. The bone turnover markers osteocalcin and bone-specific alkaline phosphatase were significantly associated with BMD change in women with negative, but not positive estrogen status. There was no conclusive evidence of a "peak age" in the baseline and follow-up BMD measures. Based on rates of BMD change, "peak" bone mineral content appears to occur before age 25 years. Factors significantly associated with lower levels of BMD were menopause without estrogen replacement, nulliparity, smoking, and age at first pregnancy. Factors associated with more bone loss were menopause without estrogen replacement, smoking, shorter duration of oral contraceptive use, and older age. Quetelet index, muscle area, number of lost pregnancies, ever breast-feeding, or calcium intake were not associated with BMD level or its 5 year rate of loss. Physical activity and alcohol intake were not associated with BMD level or change after data were adjusted for age or estrogen status.

Adult↗

PubMed1992

Platelet activating factor antagonist enhances lung preservation.

Platelet activating factor (PAF) is a potent phospholipid mediator of the immune and inflammatory responses, which causes physiologic effects similar to post-transplant pulmonary dysfunction. This study investigates the hypothesis that the use of a specific PAF antagonist (PAFA), BN 52021, in canine lung transplantation improves lung preservation. Twelve pairs of canines underwent left lung allotransplantation after pulmonary artery flushing with modified Euro-Collins (EC) solution (40 ml/kg). The experimental group (N = 6) received EC with BN 52021 (10 mg/kg). BN 52021 was administered to donors prior to harvest and to recipients prior to reperfusion. The preservation interval was 20 hr and the study period was 12 hr post-transplant. Differential pulmonary function and hemodynamics were monitored, comparing the transplanted left lung and the native right lung. Recipients were ventilated on 100% O2. Administration of the platelet activating factor antagonist, BN 52021, was associated with improvement in transplant lung oxygenation, pulmonary vascular resistance, and compliance. At 12 hr, transplant lung pulmonary venous oxygen tension in the treatment group (EC + BN 52021) was 154 +/- 21 mm Hg versus 87 +/- 10 mm Hg in the control group (EC) (P less than 0.05). Pulmonary vascular resistance of the transplant lung at 12 hr was 146 +/- 24 Dynes.sec.cm-5 in the EC + BN 52021 group as compared to 320 +/- 51 Dynes.sec.cm-5 in the EC group (P less than 0.05). Dynamic pulmonary compliance of the transplant lung at 12 hr was 32 +/- 2.9 ml/cm H2O in the EC + BN 52021 group versus 13 +/- 2.0 ml/cm H2O in the EC group (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

High energy phosphate depletion in leaflet matrix cells during processing of cryopreserved cardiac valves.

Preimplantation preparation of cardiac valves includes three major steps: (1) harvesting with accompanying ischemia (warm time from cessation of donor heart beat), (2) antibiotic disinfection, and (3) controlled-rate cryopreservation. To define the interdependent injury effects of these manipulations on leaflet matrix cells and specifically the potential for prolonged harvest-related ischemia to predispose greater injury by the subsequent steps, 96 semilunar valves were harvested from pigs in a manner analogous to human heart valve retrievals and randomly allocated to study groups as follows: 48 control valves were exposed to increasing harvested-related ischemic times, (2, 6, 12, 24 hr) and immersed in liquid nitrogen to arrest metabolic activity (i.e., prior to cryopreservation) and conclude the ischemia; another 48 were similarly harvested, subjected to identical ischemic times, then disinfected in 4 degrees C RPMI medium with standard antibiotics for 24 hr and dimethylsulfoxide cryopreserved at -1 degrees C/min to -170 degrees C (i.e., formal cryopreservation protocol). At thawing, each valve was extracted in 12% trichloroacetic acid and assayed by high performance liquid chromatography for components of the adenine nucleotide pool including ATP, lower energy nucleotides (total adenine nucleotides, [TAN] = [ATP] + [ADP] + [AMP]), adenosine, and the diffusible purines. Results are reported as nanomoles metabolite/milligram of leaflet cell protein (Lowry) and reflect a maintenance of total high energy phosphates in the control groups (5.41 +/- 0.29 nmole TAN at 2 hr; 8.34 +/- 0.67 nmole TAN at 24 hr), which fell significantly in all cryopreserved groups (1.27 +/- 0.33 nmole TAN at 2 hr; 0.34 +/- 0.22 nmole TAN at 24 hr).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenine Nucleotides↗

PubMed1992

Application of an allele-specific polymerase chain reaction to the direct determination of ABO blood group genotypes.

The allele-specific polymerase chain reaction (ASPCR) procedure has proven a powerful tool for the detection and analysis of known genetic polymorphisms. Here, we present a novel application of the ASPCR technique to determine the ABO genotypes of individuals without the need of family analysis. The method introduces a new strategy for primer design that permits the identification of the different ABO genotypes according to the molecular size of allele-specific amplification products. Four primer sets, each specific for a different set of ABO alleles, are mixed in one reaction and the amplification products are resolved on a polyacrylamide gel. Forty-one individuals belonging to various families, whose ABO phenotypes were previously determined serologically, were typed with this new variation of the ASPCR technique. A 100% correlation between the serology and the ASPCR data was found. The Mendelian segregation of ABO alleles was also demonstrated in families. The method is rapid, simple, reproducible, and specific. Potential applications include gene mapping, genetic disease diagnosis, HLA typing, paternity testing, and forensic science.

ABO Blood-Group System↗

PubMed1992

Serum albumin in older persons: relationship with age and health status.

We analyzed data from 4115 persons aged 71 years and older who had blood drawn at a home visit in three communities to examine the cross-sectional distribution of serum albumin and correlates of hypoalbuminemia. Mean albumin was lower among older persons, from 41.6 g/l in men aged 71-74 years to 38.5 g/l in men 90 years or older, and from 41.1 g/l to 38.9 g/l in women of the same ages, respectively. Hypoalbuminemia (albumin less than 35 g/l) was observed in 3.1% of subjects. Hypoalbuminemia and lower serum albumin were independently associated with anemia, recent diagnosis of cancer, two or more limitations in activities of daily living, residence in a nursing home, heavy cigarette smoking (greater than 1 pack/day), and older age. A 10-year age increment was associated with 0.8 g/l lower serum albumin and odds ratio of 1.56 (95% CI 1.14, 2.13) for hypoalbuminemia after adjusting for demographic factors and health status. Characteristics associated with serum albumin may confound the reported relationship between serum albumin and mortality.

Activities of Daily Living↗

PubMed1992

Conceptual problems in identifying risk factors for functional decline in the elderly: a commentary.

Assessment of risk factors for chronic disease and disability among the elderly is a complex issue. Findings may be affected by the age at which the putative risk factor was measured, interval between the time of measurement of risk and outcome, possibility of changing patterns of exposure throughout the life span, and selective survival. We illustrate the complexity of risk assessment with findings from the Iowa 65+ Rural Health Study on the relationship between body mass and changing physical function. In baseline cross-sectional analyses, both high and low body mass were associated with poorer function. In 6-year longitudinal analyses limited to persons who were functionally intact at baseline, high body mass was associated with poorer lower-extremity function but relatively preserved upper-extremity function. High body mass was also associated with elevated rates of transient impairments. Extremes of teenage body habitus were associated with impaired physical function in old age. Function was poorest among those with a lifetime history of high body mass, and changes in body mass were complexly associated with subsequent function. Thus conceptual and analytic models of chronic illness and disability need to consider multiple, changing exposures over the lifetime, as well as the impact of illness, disability, and their treatment on subsequent risk factor exposure.

Activities of Daily Living↗

PubMed1992

Detection of specific alleles by using allele-specific primer extension followed by capture on solid support.

This article describes a method for determining whether a particular nucleic acid sequence is present in a sample and for discriminating between any two nucleic acid sequences if such sequences differ only by a single nucleotide. The method entails extension of a novel two-component primer on templates that may or may not include a target nucleic acid sequence. The 3' portion of the primer is complementary to a portion of the template adjacent to the target sequence (for example, the polymorphic nucleotide). The 5' portion of the primer is complementary to a different preselected nucleic acid sequence. Extension of the 3' portion of the primer with a labeled deoxynucleoside triphosphate yields a labeled extension product, but only if the template includes the target sequence. The presence of such a labeled primer-extension product is detected by hybridization of the 5' portion to the preselected sequence. The preselected sequence is immobilized on a solid support. The method has been applied to genotyping individuals for the two-allele polymorphism of the human tyrosinase gene.

Alleles↗

PubMed1992

Use of medications by persons 65 and over: data from the established populations for epidemiologic studies of the elderly.

Data were analyzed from household interviews of four population-based cohorts comprising the Established Populations for Epidemiologic Studies of the Elderly to estimate the prevalence of prescription and nonprescription medication use among community-living elderly and to examine sociodemographic and health factors related to medication use. Prescription drugs were used by 60-68% of men and 68-78% of women. Nonprescription drugs were used by 52-68% of men and 64-76% of women. Use of prescription medications generally increased with age although use of nonprescription drugs was not associated with age. Men and women who smoked or used alcohol in the preceding year frequently took medications. Those who reported more depressive symptoms, impairments in physical functioning, hospitalizations, and had poorer self-perceived health status were most likely to take medications. However, 10-29% of respondents with fair or poor self-perceived health took no prescription medications, and 3-13% took neither prescription nor nonprescription medications. While further research appears warranted into potential overmedication of elders, particularly those with many depressive symptoms, these data suggest that studies of potential underuse among elders with poor health are equally important.

Activities of Daily Living↗

PubMed1992

Infected aortic aneurysms. A changing entity.

Infected (mycotic) aortic aneurysms are infrequent and, without surgical intervention, usually lead to uncontrolled sepsis or catastrophic hemorrhage. Symptoms are frequently absent or non-specific during the early stages, and a high index of suspicion is essential to make the diagnosis. Surgery performed after rupture carries high morbidity and mortality rates. Bacterial endocarditis with streptococcus pyogenes was the most common cause of infected aortic aneurysm in the pre-antibiotic era. Today, arterial trauma due to iatrogenic manipulation and depressed immunocompetence have become more common risk factors. Staphylococcus aureus and Salmonella are the most frequent bacteria identified. The authors' recent experience in six patients with infected aortic aneurysms who underwent arteriography and computed tomography was reviewed and these diagnostic methods compared. Computed tomography was found to be more sensitive in the diagnosis of the early stages of the disease, allowing for follow-up by serial scans in a noninvasive and less costly manner. Successful treatment, in four of these patients, was accomplished by aneurysmal resection and extra-anatomic bypass or in situ prosthetic reconstruction. A higher clinical awareness of this disease, leading to early computed tomography evaluation and prompt surgical intervention under appropriate and intensive antibiotic therapy, appears to offer the best chance of survival in patients with this difficult condition.

Aged↗

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

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↗