Search PubMed⌕ Search

Biomedical subjects

R B Wallace

Publications and source records attributed to R B Wallace.

At least 55 records · Page 3Linked to original sources

The health burdens of Parkinson's disease.

Parkinson's disease (PD) is likely to have a substantial impact on an individual's health-related quality of life (HRQL), health-related resource use, and productivity. Data about the health burdens of PD by disease stage are fundamental to understanding the effectiveness of care, both from a clinical and a fiscal point of view. This study's goal was to describe the associations of patient-reported HRQL and economic characteristics with PD stage. We hypothesized that later stages of PD would be associated with poorer HRQL, greater health-related resource use, and lower work productivity than early stages of PD. We used a cross-sectional analysis to study 193 PD patients attending two hospital-based neurology clinics. Self-administered questionnaires and in-person interviews measured clinical features, functional status, general health perceptions, well-being, overall HRQL, work productivity, and health-related resource use. Consistent, strong associations were found between stage and functional status, general health perceptions, well-being, and overall HRQL even after controlling for age, gender, and comorbid conditions. Most resource use and work productivity measures were also associated with disease stage. However, physician services use was not. This study confirms that the burdens of illness are progressively higher for PD patients with early, moderate, and advanced illness. The results suggest that such important facets of the health burden as HRQL and health-related resource use may be seriously misjudged if not carefully measured but inferred from clinical observations alone.

Activities of Daily Living↗

Crash risks of older drivers: a panel data analysis.

Considerable progress has been made on understanding older drivers' safety issues. None the less, findings from previous research have been rather inconclusive. Differences in data and research methodology have been suggested as factors that contribute to the discrepancies in previous findings. One of the methodological limitations is the lack of considering temporal order between events (i.e. the time between onset of medical condition, symptom and crash). Without time-series data, a 'snap-shot' of medical conditions and driving patterns were often linked to more than 1 year--of crash data, hoping to accumulate enough data on crashes. The interpretation of the results from these studies is difficult in that one cannot explicitly attribute the increase in highway crash rates to medical conditions and/or physical limitations. This paper uses a panel data analysis to identify factors that place older drivers at greater crash risk. Our results show that factors that place female drivers at greater crash risk are different from those influencing male drivers. More risk factors were found to be significant in affecting older men's involvement in crashes than older women. When the analysis controlled for the amount of driving, women who live alone or who experience back pain were found to have a higher crash risk. Similarly, men who are employed, score low on word-recall tests, have a history of glaucoma, or use antidepressant drugs were found to have a higher crash risk. The most influential risk factors in men were the number of miles driven, and use of antidepressants.

Accidents, Traffic↗

Early discharge of patients with new-onset atrial fibrillation after cardiovascular surgery.

BACKGROUND: Atrial fibrillation is one of the most frequent complications after cardiovascular surgery. It may result in thromboembolic events, hemodynamic deterioration, and an increased length and cost of hospitalization. METHODS: We retrospectively studied 504 consecutive adult patients undergoing cardiovascular surgery to determine whether patients with new-onset postoperative atrial fibrillation could be safely discharged in atrial fibrillation after ventricular rate had been controlled and anticoagulation initiated. RESULTS: Postoperative atrial fibrillation occurred in 79 (16.2%) of the 487 survivors. Of these patients, 67 were discharged in sinus rhythm, whereas the remaining 12 were discharged in atrial fibrillation. Patients discharged in atrial fibrillation tended to be older, have higher Parsonnet risk scores, and have an increased incidence of valvular heart surgery. Despite this result, this cohort had a shorter length of hospital stay (7.3+/-2.0 days vs 10.9+/-9.3 days, p = 0.006), decreased hospital costs ($14,188+/-$2635 vs $23,016+/-$21,963, p = 0.002), and decreased hospital charges ($37,878+/-$7420 vs $58,289+/-$50,980, p = 0.003) compared with patients with atrial fibrillation discharged in sinus rhythm. In the 12 persons discharged home in atrial fibrillation, no repeat hospitalizations, bleeding complications, or thromboembolic events occurred. CONCLUSION: A strategy of early discharge of patients with persistent postoperative atrial fibrillation appears promising and deserves prospective testing on a larger scale.

Adult↗

Heparin preserves nitric oxide activity in coronary endothelium during ischemia-reperfusion injury.

BACKGROUND: Brief episodes of ischemia followed by reperfusion adversely affect endothelial vasomotor function. We hypothesized that heparin may impart a protective effect on the coronary endothelium during ischemia-reperfusion injury possibly via the nitric oxide pathway. METHODS: Eighteen anesthetized dogs were randomly assigned to one of two treatment groups: saline solution or bovine heparin (6.0 mg x kg intravenously). A flow probe and cannula were placed in the left anterior descending artery. Functional recovery of the coronary endothelium was assessed after 15 minutes of ischemia and during 120 minutes of reperfusion after acetylcholine and nitroprusside challenge. In a separate group (n = 10), nitric oxide activity was measured as nitrate/nitrite levels and cyclic guanosine monophosphate levels in the left anterior descending artery. RESULTS: Control dogs displayed a significant decrease in percent change of left anterior descending artery flow at 15, 30, and 60 minutes of reperfusion (67%+/-8%, 76% +/-11%, and 84%+/-8%) when compared with preischemic values (108+/-6; p < 0.01). Heparinized dogs, however, showed preservation of coronary endothelial function after acetylcholine challenge throughout reperfusion. Heparin-treated dogs also displayed a significant increase in nitrate/nitrite levels during reperfusion (37.3+/-4.1 micromol/L) when compared with the saline group (24.3+/-0.8 micromol/L; p < 0.03). Left anterior descending artery levels of cyclic guanosine monophosphate were also significantly increased after heparin administration (3.0+/-0.3 pmol/mg) when compared with ischemia-reperfusion alone (0.7+/-0.1 pmol/mg; p < 0.03). CONCLUSIONS: Heparin preserves the vasoregulatory function of the coronary endothelium during brief episodes of ischemia-reperfusion injury, in part, via the nitric oxide pathway. Administration of heparin may have important therapeutic implications in the prevention of coronary endothelial dysfunction associated with reperfusion injury.

Animals↗

Heparin and nonanticoagulant heparin preserve regional myocardial contractility after ischemia-reperfusion injury: role of nitric oxide.

OBJECTIVES: These studies were performed to determine the effect of heparin and nonanticoagulant heparin on myocardial function after ischemia-reperfusion and to further evaluate the role that the nitric oxide-cyclic guanosine monophosphate pathway plays in mediating the effect of heparin. METHODS: Fifteen dogs were subjected to 15 minutes ischemia followed by 120 minutes reperfusion and pretreated with either saline solution, bovine heparin (6.0 mg/kg intravenously), or N-acetyl heparin (6.0 mg/kg intravenously), a heparin derivative without anticoagulant properties. The left anterior descending artery was occluded for 15 minutes and regional systolic shortening, a unitless measure of myocardial contractility, assessed during reperfusion. To evaluate the role of nitric oxide, the inhibitor N(omega)-nitro-L-arginine, 1.5 mg/kg intracoronary, was given before heparin administration. Myocardial levels of cyclic guanosine monophosphate, the second messenger of nitric oxide, were also measured in the N-acetyl heparin group using radioimmunoassay. RESULTS: Regional systolic shortening was significantly decreased in the saline group during 60 and 120 minutes compared with before ischemia (9.2 +/- 1.0 and 9.0 +/- 0.9 vs 12.2 +/- 1.2, p < or = 0.0003). Heparin and N-acetyl heparin-treated dogs, however, showed preservation of systolic shortening throughout reperfusion. Administration of nitro-L-arginine significantly attenuated the protective effect of heparin (9.2 +/- 1.2 vs 12.7 +/- 1.1, p < or = 0.0001) and N-acetyl heparin (9.3 +/- 0.3 vs 12.8 +/- 0.4, p < or = 0.0001) during 120 minutes reperfusion. Myocardial levels of cyclic guanosine monophosphate were also significantly increased in the N-acetyl heparin group compared with saline (199.1 +/- 7.1 vs 103.5 +/- 4.5 pmol/mg, p < or = 0.0001). CONCLUSIONS: Heparin preserves myocardial contractility after ischemia-reperfusion independent of its anticoagulant properties. Furthermore, the protective effects of heparin during ischemia-reperfusion are mediated, at least in part, through a nitric oxide-cyclic guanosine monophosphate pathway.

Animals↗

The usefulness of the Functional Status Questionnaire and Medical Outcomes Study Short Form in Parkinson's disease research.

Parkinson's disease (PD) has no cure and is a progressive neurological disorder with treatment aimed at the maintenance of function and limitation of the symptoms. No extensive studies of the disease's impact on health-related quality of life (HRQoL) have been conducted. The purpose of this study was to assess the potential usefulness of the Medical Outcomes Study Short Form (SF-36) and the Functional Status Questionnaire (FSQ) in Parkinson's disease research. This cross-sectional study of 193 PD patients who visited two hospital-based neurology clinics used self-administered in-clinic and take-home questionnaires to ascertain the demographic and environmental characteristics of the subjects and to gain health profile measures from the SF-36 and the FSQ. The two health profiles provide important HRQoL information supplementary to the traditional signs and symptoms evaluated by the Unified Parkinson's Disease Rating Scale (UPDRS). Many of the HRQoL measures discriminate progressive stages of disease in this study group and distinguish those with complications of therapy from subjects without complications.

Activities of Daily Living↗

Variation in tertiary prevention and health service utilization among the elderly: the role of urban-rural residence and supplemental insurance.

OBJECTIVES: Tertiary prevention seeks to reduce chronic disease progression and illness-related dysfunction. Using the Aday-Andersen model, we evaluated the impact of predisposing, need, and enabling factors on tertiary prevention, hypothesizing that urban-rural geographic differences in delivery would be detected. METHODS: A population-based telephone survey was conducted evaluating six common chronic indicator conditions: arthritis (n = 488), hypertension (n = 414), cardiac disease (n = 185), diabetes mellitus (n = 125), peptic ulcer disease (n = 125), and chronic obstructive pulmonary disease (n = 103). Subjects were 787 (70% women) home-dwelling elderly (age > 65 years) who had one or more of the indicator conditions and who resided in Iowa's 12 most rural and 10 most urban counties. Tertiary prevention measures included counseling for and/or treatment with: influenza and pneumococcal vaccination, smoking cessation, dietary modifications, exercise, drug side effects, chronic disease rehabilitation, aspirin/estrogen for cardiac disease, and foot/eye care for diabetes. Tertiary prevention scores were calculated to compare preventive services across disease categories and to examine relations, in particular, with enabling factors. RESULTS: Education beyond high school, alcohol use, cigarette smoking, and medical specialist use were all significantly greater among urban residents, whereas home services use was greater among rural residents. Respondents with either health maintenance organization or fee-for-service supplemental coverage had higher tertiary prevention scores than respondents without supplemental coverage. After adjustment for the significant effects of the number of diseases, higher income, and place of residence, rural respondents having health maintenance organization supplemental coverage had higher (better) tertiary prevention scores than other respondents. CONCLUSIONS: In this community-based study of elderly, enrollment in an health maintenance organization plan, as opposed to a fee-for-service supplement to Medicare, increased tertiary prevention quality for rural but not for urban residents. This study emphasizes that additional research is needed to evaluate the importance of specific types of insurance coverage for preventive services among the elderly.

Aged↗

Multifocal vision after cataract surgery.

Recent improvements in cataract surgery and intraocular lens (IOL) technology have allowed rapid improvement in quality visual acuity. Cataract surgeons can also reliably reduce a patient's dependency on spectacles. Through careful monitoring of implant power calculations to improve their accuracy and reduce unwanted astigmatism, our patients are now able to enjoy clear, uncorrected vision. Newer technology, such as multifocal IOLs and accommodating IOLs, can provide a return to prepresbyopic visual acuity for the cataract patient.

Cataract Extraction↗

The impact of education and heart attack on smoking cessation among middle-aged adults.

Considerable evidence supports the premise that higher levels of education lead to enhanced health, including protective health behaviors. This paper focuses on how education affects one health behavior known to lead to enhanced health: the cessation of smoking. In particular, the authors examine the extent to which education influences the decision by middle-aged adults to quit smoking following a heart attack, a potentially life-threatening health event. We first hypothesize that middle-aged adults with more formal education will stop smoking more readily than people with less formal education following the experience of a heart attack. Second, we ask what other factors might underlie and explain that hypothesized effect. Using longitudinal data, the authors track changes in individual smoking behaviors after a heart attack among preretirement-age Americans. We control for documented correlates of smoking and heart attack plus other factors associated with education, heart attack, and smoking that may also influence whether a person quits smoking. In addition to confirming evidence on the education-health association as well as the documented connection between heart attack and smoking cessation, this study provides a surprising twist on those links: Our results show that the move to quit smoking following the experience of a heart attack among middle-aged adults is significantly and dramatically moderated by their level of educational attainment.

Education↗

Application of capillary electrophoresis to the measurement of oligonucleotide concentration and purity over a wide dynamic range.

Synthetic oligonucleotides rarely contain 100% of the full-length sequence due, in part, to the failure sequences produced during synthesis. In this paper, a method is described for the determination of both the concentration and the purity of oligonucleotides, utilizing capillary electrophoresis with a deoxyribo-nucleoside triphosphate as an internal standard. This method is advantageous for several reasons: (a) the wide dynamic range allows for the analysis of samples without the need for dilutions; (b) a small sample size is used for analysis; (c) capillary electrophoresis is automatable which allows for high throughput; and (d) all of the samples are analyzed at the same run temperature which aids in reproducibility and consistency between runs performed at different times.

Deoxyadenine Nucleotides↗

Medical history risk factors for non-Hodgkin's lymphoma in older women.

BACKGROUND: It has been suggested that certain medical conditions and drug exposures might suppress the immune system and increase the risk of developing non-Hodgkin's lymphoma (NHL). PURPOSE: We investigated whether specific medical conditions and drug exposures were associated with the risk of NHL in a cohort of older women who were enrolled in the Iowa Women's Health Study. METHODS: A cohort of 41837 women, 55-69 years of age at baseline, was followed prospectively for the development of cancer from 1986 through 1992. These women had completed a baseline questionnaire in January 1986 that inquired about the occurrence and age at onset of specific medical conditions, about family history of cancer, and about the use of selected medications. Follow-up questionnaires were mailed to the women in 1987, 1989, and 1992. Incident cancers and deaths were ascertained through linkages to state and national databases. For most analyses, women with a self-reported history of cancer at baseline (n = 3903) were excluded. Relative risks (RRs) and 95% confidence intervals (CIs), adjusted for age or for age and other variables, were used as a measure of the association between NHL and medical history factors. Reported P values are two-sided. RESULTS: One hundred fourteen incident cases of NHL were identified in the cohort during follow-up. A history of adult-onset diabetes mellitus (i.e., first diagnosed after the age of 30 years) was associated with an increased risk of developing NHL (age-adjusted RR = 2.18; 95% CI = 1.22-3.90). In addition, there was an association between the duration of adult-onset diabetes and increasing risk of NHL (P for trend = .004), with an age-adjusted RR of 2.90 (95% CI = 1.07-7.90) for women with a diagnosis of diabetes for 15 or more years compared with women with no diagnosis of diabetes. Women with a history of blood transfusion were also at increased risk for the development of NHL (age-adjusted RR = 1.95; 95% CI = 1.33-2.85). The risk estimates for diabetes and transfusion history were independent of each other and were not changed substantially after adjustment for other risk factors. History of a previous cancer (excluding hematopoietic and lymphatic cancers) was associated with an increased risk of NHL (age-adjusted RR = 1.92; 95% CI = 1.21-3.06); this risk estimate was attenuated somewhat after adjustment for a history of diabetes, transfusion history, and other major risk factors (RR = 1.66; 95% CI = 1.02-2.69). No statistically significant associations were found between NHL and a history of chronic colitis, nonestrogen steroid use, use of exogenous estrogens, or use of thyroid medications. CONCLUSIONS AND IMPLICATIONS: A history of adult-onset diabetes mellitus, blood transfusion, and a history of cancer (or its treatment) appear to be independent risk factors for NHL in older women.

Age of Onset↗

Serum iron level, coronary artery disease, and all-cause mortality in older men and women.

The association between iron levels and coronary artery disease (CAD) mortality is controversial. Whereas most data show no association, some have raised the possibility of a causal role, while others have suggested a protective effect of iron on CAD. To address these possibilities, we examined the association between serum iron and CAD, cardiovascular disease, and all-cause mortality in a large cohort of 3,936 persons aged > or =71 years who completed an interview, had a serum iron determination, and survived at least 1 year after baseline. The median follow-up time was 4.4 years. Serum iron levels were categorized according to sex-specific quartiles. Relative risks (RR) and 95% confidence intervals (CI) were calculated from proportional-hazards regression models adjusted for age, race, education, creatinine, serum albumin, serum lipids, use of iron supplementation, smoking, use of alcohol, blood pressure, body mass index, and presence of chronic conditions. There was a gradual decrease in the RRs of CAD, cardiovascular disease, and all-cause mortality with increasing serum iron levels (all tests for trend, p <0.05). Men in the highest iron quartile were one fifth as likely to die of CAD as men in the lowest iron quartile (RR 0.22; 95% CI 0.11 to 0.48), and women in the highest quartile had half the risk of women in the lowest quartile (RR 0.48; 95% CI 0.27 to 0.87). When compared with the lowest quartile, risk of all-cause mortality was 38% lower in men in the highest iron quartile (RR 0.62; 95% CI 0.46 to 0.85) and 28% lower in women in the highest quartile (RR 0.72; 95% CI 0.53 to 0.96). Results of similar strength and magnitude were observed for cardiovascular disease mortality and in analyses that excluded the first 3 years of follow-up. In this large cohort of persons aged > or =71 years, there was consistent evidence of increasing risk of mortality at lower serum iron levels. In fact, lower serum iron levels were associated with an increased risk of CAD, cardiovascular disease, and all-cause mortality. The results are compatible with the possibility that in an older population, there is an inverse association between serum iron levels and risk of mortality.

Age Factors↗

Lack of association of a polymorphism in the low-density lipoprotein receptor-related protein gene with Alzheimer disease.

BACKGROUND: The apolipoprotein E epsilon 4 (ApoE epsilon 4) allele is associated with an increased risk for development of Alzheimer disease (AD). We hypothesized that polymorphisms in proteins that interact with ApoE also might have an impact on the likelihood of AD developing. We examined a polymorphism in the gene for the low-density lipoprotein receptor-related protein (LRP), because LRP is a major ApoE receptor in the brain that also mediates binding and degradation of secreted Kunitz protease inhibitor forms of amyloid precursor protein. SUBJECTS AND DESIGN: The LRP genotypes in 2 groups were studied. The first group consisted of 130 patients with probable or definite AD (mean +/- SD age, 78.2 +/- 8.9 years) and 64 nondemented, control subjects (mean +/- SD age, 81.7 +/- 12.3 years) who were primarily the spouses of the patients. The second group consisted of individuals from a population-based, epidemiologic study, including 38 cognitively impaired individuals (mean +/- SD age, 79.9 +/- 4.1 years) and 93 nondemented controls (mean +/- SD age, 78.7 +/- 4.4 years). Finally, 22 brains with a neuropathological diagnosis of AD were evaluated for neuronal loss, beta-amyloid deposition, and neurofibrillary tangle number and compared with the LRP genotype. RESULTS: No genetic disequilibrium in LRP allele frequencies between controls and patients with AD or cognitive impairment was observed. No interaction between the ApoE epsilon 4 and LRP genotypes was observed in patients with AD. Moreover, the LRP genotype did not correlate with degree of neuronal loss, beta-amyloid deposition, or neurofibrillary tangle number in individuals examined using quantitative neuropathological techniques. CONCLUSION: This LRP gene polymorphism is not linked with the pathophysiological changes of AD.

Aged↗

Gender, self-reported depressive symptoms, and sleep disturbance among older community-dwelling persons. FICSIT group. Frailty and Injuries: Cooperative Studies of Intervention Techniques.

The purposes of this report are: (1) to investigate the association between sleep disturbances and depressive symptomatology in older adults; (2) to evaluate the degree to which gender serves to mediate this relationship; and (3) to determine whether several predefined covariates help to explain the association between sleep disturbance and depressive symptoms. This is a retrospective and cross-sectional analysis of baseline data from 485 elderly adults enrolled in three of the eight clinical sites participating in the Frailty and Injuries: Cooperative Studies of Intervention Techniques (FICSIT) trials. FICSIT was a linked series of randomized clinical trials which evaluated the impact of various exercise interventions on several measures of frailty in older adults. Women reported more depressive symptoms and more sleep disturbances than men. Sleep disturbances were independently associated with depressive symptoms, bodily pain, a history of falling, limited education, being married, and being female. Gender interactions suggest that, although women reported more depressive symptoms and more chronic health conditions than men, both may be more important predictors of sleep disturbance in men. By contrast, being married may be more predictive in women. Finally, the data suggest a stronger relationship between sleep disturbance and depressive symptoms in men than in women.

Activities of Daily Living↗

Epidemiology of alcohol use in a group of older American Indians.

PURPOSE: This study describes alcohol use in a group of older American Indians and the associations with demographic and health status characteristics, by gender. METHODS: Alcohol use was examined in a cross-sectional, population-based study of 161 American Indians, aged 45-76 years (a substudy of the Strong Heart Study). Alcohol use was measured by a questionnaire administered during a personal interview. Information about demographic characteristics and health status was ascertained from interviews and abstraction of medical records. RESULTS: A higher proportion of men than women had used alcohol heavily (71% vs. 28%). Men were more likely than women to drink currently (46% vs. 18%), to binge (26% vs. 5%), and to screen positive for alcoholism (77% vs. 43%). Among current drinkers, > 30% had diabetes, and the average score on the Short Michigan Alcoholism Screening Test (SMAST) was in the alcoholic range. Heavy drinking was associated with more symptoms of depression in women (P < 0.05) and fewer in men (P < 0.05). Alcoholism was positively associated with a history of heavy drinking in both men (P < 0.05) and women (P < 0.001). CONCLUSIONS: Alcohol use was common and varied by gender. Alcohol use also varied according to other sociodemographic and health status characteristics. Since many older American Indians with chronic illness are currently drinking, this age group may require enhanced alcohol control programs.

Age Distribution↗

Association of smoking, body mass, and physical activity with risk of prostate cancer in the Iowa 65+ Rural Health Study (United States).

Smoking, obesity, alcohol, and physical activity can modulate the endocrine system, and therefore have been hypothesized to play a role in the etiology of prostate cancer. At baseline in 1982, 80 percent (n = 3,673) of the noninstitutionalized persons age 65+ in two rural Iowa (United States) counties were enrolled into the Iowa 65+ Rural Health Study. Follow-up for mortality was complete through 1993, and cancer experience was determined by linkage to the State Health Registry of Iowa cancer database for the years 1973-93. We analyzed data on 1,050 men aged 65 to 101 years (mean age 73.5) with a full interview in 1982 and with no documented cancer in the 10 years prior to baseline. Through 1993 (8,474 person-years of follow-up), there were 71 incident cases of prostate cancer. In a multivariate model, age, cigarette smoking (relative risk [RR] = 2.9 for currently smoking 20 or more cigarettes per day compared with never smoking; P trend = 0.009), greater body mass index (BMI) (wt/ht2) (RR = 1.7 for BMI > 27.8 kg/m2 compared with < 23.6; P trend = 0.1), and greater level of physical activity (RR = 1.9 for high activity level cf inactive; P trend = 0.05) were independent predictors of prostate cancer, and these associations were stronger for regional or disseminated disease at diagnosis. Percent change in BMI from age 50 to baseline was associated positively with risk (P trend = 0.01), and this association appeared to be stronger in heavier men. There were no data on diet. These findings suggest that smoking, overweight, and weight gain in later life are risk factors for prostate cancer and support a hormonal etiology; the positive association for physical activity confirms some previous reports, but remains without a credible biologic mechanism.

Age Distribution↗

Loneliness and nursing home admission among rural older adults.

In this study, the authors tested the relation between loneliness and subsequent admission to a nursing home over a 4-year time period in a sample of approximately 3,000 rural older Iowans. Higher levels of loneliness were found to increase the likelihood of nursing home admission and to decrease the time until nursing home admission. The influence of extremely high loneliness on nursing home admission remained statistically significant after controlling for other variables, such as age, education, income, mental status, physical health, morale, and social contact, that were also predictive of nursing home admission. Several mechanisms are proposed to explain the link between extreme loneliness and nursing home admission. These include loneliness as a precipitant of declines in mental and physical health and nursing home placement as a strategy to gain social contact with others. Implications for preventative interventions are discussed.

Activities of Daily Living↗