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Biomedical subjects

J W Rowe

Publications and source records attributed to J W Rowe.

At least 19 recordsLinked to original sources
PubMed1997

Increase in urinary cortisol excretion and memory declines: MacArthur studies of successful aging.

Cortisol production is increased during stress, and the actions of cortisol on receptors in the brain and other body organs are involved in allostasis, the process of adaptation to stress, as well as in allostatic load, the wear and tear associated with excessive exposure to cortisol. Using data from a community-based longitudinal study of older men and women, aged 70-79 yr, we tested the hypothesis that exposure to increasing levels of cortisol is associated with declines in memory performance. Associations between 12-h urinary free cortisol excretion and performance on tests of memory (delayed verbal recall and spatial recognition), abstraction, and spatial ability were examined. Among the women, greater cortisol excretion was associated with poorer baseline memory performance, independent of socio-demographic, health status, health behavior, and psychosocial characteristics. Moreover, women who exhibited increases in cortisol excretion over a 2.5-yr follow-up period were more likely to show declines in memory performance. By contrast, women who experienced declines in cortisol exhibited improvements in memory performance. No significant associations were found among the men. The results for the women suggest that decrements in memory performance associated with increases in cortisol may not represent irreversible effects, as declines in cortisol were associated with improvements in memory.

Aged↗
PubMed1995

Self-esteem and neuroendocrine response to challenge: MacArthur studies of successful aging.

The role of self-esteem in modulating patterns of neuroendocrine response to challenge at older ages was examined in 16 healthy 70-yr-olds. Responses to two challenges were examined: (1) a driving simulation designed to reflect a 'real life' challenge situation; and (2) a pharmacologic, corticotropin-releasing-hormone (CRH) challenge (1 micrograms/kg). Both challenges evoked significant elevations in cortisol and adrenocorticotropic hormone (ACTH). Levels of self-esteem were significantly and negatively associated with peak elevations in cortisol in response to the driving simulation challenge (r = -0.51, p = 0.04). ACTH responses showed similar trends (r = -0.41, p = 0.12). Self-esteem levels were not correlated with responses to the CRH challenge. These data indicate that psychological characteristics such as self-esteem may play a role in modulating patterns of neuroendocrine response to cognitive/behavioral challenges in everyday life in older individuals.

Activities of Daily Living↗
PubMed1995

Lipid provisioning of turtle eggs and hatchlings: total lipid, phospholipid, triacylglycerol and triacylglycerol fatty acids.

Lipid composition of eggs and hatchlings was studied in painted, snapping and Blanding's turtles from western Nebraska. The average total lipid proportions of the egg yolk, post-embryonic yolk and hatchling soma dry masses were high in painted turtles (29.80%, 42.16% and 14.18%, respectively) relative to snapping and Blanding's turtles (egg yolk < 14%, postembryonic yolk < 17%, hatchling soma < 2%). The proportion of total egg yolk lipid used during development varied among species (painted turtles, x = 45.4%; snapping turtles, x = 68.9%; Blanding's turtles, x = 86.6%). Total lipid data are consistent with patterns reported for turtle species whose hatchlings overwinter in the nest (e.g., painted turtles) vs those whose hatchlings emerge in the fall (e.g., snapping and Blanding's turtles). In all species, the total lipid quantity of egg and hatchling components was primarily triacylglycerol (> 63%), an energy storage form. Predominant triacylglycerol fatty acids in eggs and hatchlings were 16:0, 16:1 and 18:1, and concentration changes of some yolk fatty acids occurred during development. The average phospholipid (a membrane form) quantity of the egg and hatchling components was relatively low in painted turtles (< 2% of the total lipid). In snapping and Blanding's turtles, the relatively large phospholipid proportion of the post-embryonic yolks (approximately 7%) could potentially contribute more to post-embryonic growth in these species than the phospholipids of painted turtle post-embryonic yolks.

Animals↗
PubMed1995

Predictors of cognitive change in older persons: MacArthur studies of successful aging.

This study used a linear structural relations modeling technique (LISREL) to examine longitudinal data for 1,192 persons from a community-based population. The goal was to test the ability of an a priori model to predict cognitive change over a 2.0- to 2.5-year period in older adults aged 70-79 at the initial evaluation. The model included 22 demographic, physical, and psychosocial variables as predictors of cognitive function and cognitive change. The study used an exploratory-confirmatory design, enabling cross-validation of the model developed in the exploratory set in the confirmatory sample. Structural equation modeling analyses identified 4 endogenous model variable (education, strenuous activity, peak pulmonary expiratory flow rate, and self-efficacy) as direct predictors of cognitive change over the study period.

Aged↗
PubMed1994

Predicting changes in physical performance in a high-functioning elderly cohort: MacArthur studies of successful aging.

BACKGROUND: Performance-based measures of physical performance were examined for an older cohort of relatively high-functioning men and women. Relationships between baseline physical performance and sociodemographic and health status characteristics were also examined. Three-year pattern changes in performance are described, and sociodemographic and health status predictors of change are investigated. METHODS: A cohort of relatively high-functioning men and women, aged 70-79, was identified in 1988 by subsampling from three community-based studies on the basis of physical and cognitive function. Baseline in-home assessments included tests of physical performance and measurement of sociodemographic characteristics and health status. A summary measure of physical performance was developed from tests of balance, gait, lower body strength and coordination, and manual dexterity. In-home assessments were repeated at follow-up in 1991. RESULTS: Better physical performance at baseline was more common among males, Whites, those reporting higher income and education, and those with fewer chronic conditions. In linear regression models, declines in performance were predicted by older age, lower income, higher education, relative weight and blood pressure, lower peak expiratory flow, prevalent diabetes and incident health conditions and hospitalizations during follow-up. Improvements in performance were also observed; the only significant association was with race (i.e., being Black). CONCLUSIONS: Declines in physical performance within a high-functioning cohort are predictable from sociodemographic and health status characteristics. The patterns of both decline and improvement in performance observed in this cohort suggest that older age is not uniformly associated with declines, indicating the potential for effective interventions to promote more successful aging.

Activities of Daily Living↗
PubMed1993

The pituitary-adrenal glucocorticoid response is altered by gender and disease.

BACKGROUND: This study examined the role of age, gender, and disease in the regulation of the pituitary-adrenal axis. METHODS: Serum cortisol and immunoreactive corticotropin (ACTH) were measured for five hours after a bolus administration of ovine corticotropin releasing hormone (oCRH, 1 microgram/kg) during three separate investigations: 1) age: comparison was made between young men (26 +/- 3 years [means +/- SE]) vs old men (73 +/- 2 years); 2) gender: comparison between old men (73 +/- 2 years) vs old women (68 +/- 3 years); and 3) disease: comparison was made between healthy subjects (no disease, 44 +/- 6 years) vs subjects with a chronic stable disease (diabetes mellitus [DM] or hypertension [HBP], 48 +/- 5 years). RESULTS: Basal concentrations of cortisol were significantly higher in younger men (127 +/- 17 vs 74 +/- 11 nmol/L, p < .03), as were peak cortisol levels (499 +/- 30 vs 397 +/- 36 nmol/L, p < .05, ANOVA). However, the 5-hour nadir of cortisol, area under the curve, delta area under the curve, time to peak, and variability of the responses during three separate admissions were similar in young and old. When the responses to oCRH in old men and old women were compared, old women had significantly higher basal values of cortisol (163 +/- 30 vs 75 +/- 11 nmol/L, p < .02), peak levels of cortisol (p < .0001) and the 5-hour nadir of cortisol was 124% higher in older women (657 +/- 61 vs 298 +/- 50 nmol/L, p < .0006). When the response to oCRH was examined in healthy subjects and subjects with disease (DM and HBP), men with disease had a peak cortisol response 40% higher (p < .003) than healthy men and the level remained 85% higher (p < .0005) at 5 hours. The responses of ACTH to oCRH were not different in the groups being compared for any study. The variation of cortisol response could be explained by the peak cortisol levels (R2 = .718, p < .0001), with a small significant contribution from disease (R2 = .013, p < .002). In summary, the adrenal response to oCRH remained elevated throughout the period of study in elderly women. In addition, subjects with a chronic disease (DM and HBP) had a greater response of cortisol to oCRH compared with healthy subjects. CONCLUSION: This study demonstrated that the pituitary-adrenal response to oCRH in the elderly is gender specific and chronic stable disease (DM and HBP) is associated with altered regulation of the adrenal glucocorticoid response.

Adrenocorticotropic Hormone↗
PubMed1993

Acute delirium and functional decline in the hospitalized elderly patient.

BACKGROUND: Delirium is often considered a transient cognitive syndrome. Its effect on long-term physical function, however, has not been well defined. METHODS: In a prospective study of 325 hospitalized community and nursing home elderly, we analyzed the effect of in-hospital delirium on subsequent physical function. ADL performance was assessed prior to admission, and at 3 and 6 months after hospital discharge. RESULTS: There was a strong univariate (unadjusted) association between incident delirium and functional decline (p < .02). Delirious subjects lost a mean of almost one ADL, as measured 3 months after hospital discharge. Using multivariate linear regression analysis, with adjusted change in function as the dependent variable, delirium persisted as the sole predictor of loss of function (p = .009) at 3 months after discharge. The functional decline persisted at 6 months after hospital discharge. CONCLUSION: This finding of a nontransient, perhaps permanent consequence of delirium invites reexamination of the definition of delirium from that of an acute, reversible syndrome to one of acute onset with long-term sequelae.

Activities of Daily Living↗
PubMed1993

Measured versus estimated creatinine clearance in a high-functioning elderly sample: MacArthur Foundation Study of Successful Aging.

OBJECTIVE: To assess the validity of several equations for estimating creatinine clearance in a large sample of high-functioning, community-dwelling elderly. DESIGN: Serum and 12-hour urine samples were collected and assayed for creatinine using the Jaffe total chromagen method. Fifteen clearance-estimating equations were evaluated for bias, accuracy, correlation with measured clearance values, and frequency of erroneous placement into renal function categories. Stepwise regression modeling and reliability testing were performed on a split sample to construct and assess a novel creatinine-clearance-estimating equation. SETTING: New Haven, Connecticut, East Boston, Massachusetts, and a five-county region in and around Durham, North Carolina. PARTICIPANTS: A subsample of community-dwelling men and women (age range 70-79 years) from the Established Populations for Epidemiological Studies of the Elderly was screened for physical and cognitive functioning and placed into high-, medium-, and low-functioning groups (n = 1354). High-functioning respondents who provided blood and complete urine samples (n = 762) were included in the present study. RESULTS: In general, estimated creatinine clearance was more closely correlated to measured values in males than in females. Most equations underestimated creatinine clearance, with average bias ranging from -33.1 mL/min to +19.6 mL/min. Predictive accuracy ranged from 18.2 mL/min to 38.0 mL/min. Equations were variable in their erroneous placement of individuals into renal function categories. Regression modeling yielded an equation which contained novel components but failed to provide better estimates of creatinine clearance than those already available. CONCLUSIONS: The equations evaluated here provide unacceptable predictions of creatinine clearance in normally aging individuals. We advocate the use of serum drug concentration measurements when available and encourage investigation into timed urine collections of short duration as alternatives to clearance-estimating equations in the elderly.

Activities of Daily Living↗
PubMed1992

Risk factors for delirium in hospitalized elderly.

OBJECTIVE: To determine risk factors for delirium in elderly hospitalized patients. DESIGN: Cohort analytic study. Using a reliable and valid instrument for detection of delirium, we prospectively followed up a cohort of elderly patients admitted to an acute care hospital. Using standardized criteria, we collected risk factor data from patient medical records. SETTING: General medical and surgical wards of a tertiary-care hospital. PATIENTS: Patients (n = 325) were 65 years of age or older, from either a geographically defined community or a long-term-care institution. We studied those patients (n = 291) not delirious on first evaluation. Fifty-seven patients or their families refused participation. MAIN OUTCOME MEASURES: Incidence of delirium and risk factors calculated as adjusted odds ratios (ORs). MAIN RESULTS: Delirium developed in 91 patients. By stepwise logistic regression, the independent risk factors for in-hospital delirium included prior cognitive impairment (OR, 8.97; 95% confidence interval [CI], 3.99 to 20.14), age over 80 years (OR, 5.22; 95% CI, 2.60 to 10.46), fracture on admission (OR, 6.57; 95% CI, 2.23 to 19.33), symptomatic infection (OR, 2.96; 95% CI, 1.42 to 6.15), and male sex (OR, 2.40; 95% CI, 1.19 to 4.84). Among medication groups, only neuroleptic use (OR, 4.48; 95% CI, 1.82 to 10.45) and narcotic use (OR, 2.54; 95% CI, 1.24 to 5.18) were independently associated with delirium. Anticholinergic use was not associated with delirium. CONCLUSIONS: Delirium in hospitalized patients is most closely associated with factors already present on admission such as prior cognitive impairment, advanced age, and fracture. In the hospital, use of neuroleptics and narcotics and the presence of infection are less strongly associated with this syndrome.

Age Factors↗
PubMed1991

Blood pressure, pulse, and neurohumoral responses to nitroprusside-induced hypotension in normotensive aging men.

In order to assess the effects of age on blood pressure, pulse, and neurohumoral responses to hypotensive stress, we infused nitroprusside into healthy young and old men until mean arterial blood pressure was reduced 20% from basal. Elderly subjects were much more sensitive to nitroprusside. Pulse increases in response to this hypotensive stress were markedly reduced in the elderly, but renin, vasopressin, and norepinephrine responses were not different between young and old. We conclude that cardioacceleration, one of the primary defenses against hypotension, is impaired with age. However, neurohumoral responses to hypotension are intact in the elderly.

Adult↗
PubMed1991

Age-related alterations in pulsatile secretion of TSH: role of dopaminergic regulation.

To investigate the influence of aging on dopaminergic modulation of pulsatile thyrotropin (TSH) secretion, we examined changes in circulating TSH levels during the day and night, with and without a dopamine antagonist metoclopramide, in healthy young (20-35 yr old) and old (69-83 yr old) subjects, with the use of cluster analysis. Baseline thyroid function tests including serum thyroxine, 3,5,3'-triiodothyronine (T3), T3 resin uptake, and TSH and the response of TSH to thyrotropin-releasing hormone were within normal limits in young and old subjects, and antimicrosomal and anti-thyroglobulin antibodies were absent in all participants. Pulsatile TSH secretion was identified in all subjects, and as a group there were significant increases in nocturnal peak height (P less than 0.01), amplitude (P less than 0.01), and mean TSH (P less than 0.001). TSH pulse amplitude increased 160% (P less than 0.05) at night compared with day in the young but was unchanged at night in the old. After the administration of metoclopramide there was a significant increase in peak height (P less than 0.01), amplitude (P less than 0.01), and mean TSH (P less than 0.01). However, the effect of metoclopramide was different in young and old subjects. In the young, daytime administration of metoclopramide increased TSH pulse height (P less than 0.02) and mean TSH (P less than 0.05); pulse parameters remained unchanged at night. In comparison, in old subjects after metoclopramide, pulse parameters were unchanged during the day but pulse amplitude significantly (P less than 0.01) increased at night. TSH pulse frequency remained stable with age and was unaltered after metoclopramide.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Dopaminergic regulation of gonadotropin and thyrotropin hormone secretion is altered with age.

To determine if age-related changes in glycoprotein pituitary hormone secretion are associated with alterations in dopaminergic regulation, plasma gonadotropins and TSH were measured before and after L-dopa administration in 44 young (31-44 years of age) and 42 old (64-88 years of age) healthy male participants. Plasma GH and PRL were also determined in order to examine the somatotroph and lactotrope response. In the young, following L-dopa, plasma FSH, LH and TSH were unchanged from baseline. However, in older subjects, plasma FSH was significantly increased (p less than 0.001) and a similar trend was noted for LH. Plasma TSH was significantly depressed (p less than 0.002) in older subjects only. Following L-dopa, increases in plasma GH and decreases in plasma PRL were of similar magnitude in each group. These data indicate that dopaminergic modulation of gonadotropins and TSH is altered with age.

Adult↗
PubMed1990

Older patients' health status and satisfaction with medical care in an HMO population.

Few studies have examined the relationship between older patients' satisfaction with medical care and their health status, and none of these investigations has been based at an HMO. To examine this question, data on 532 patients older than 70 years in an HMO were analyzed. Patients' reports of satisfaction with medical care were examined in relation to several dimensions of health status (based on self-reports, chart data, and physicians' ratings), their own sociodemographic characteristics, and characteristics of their primary physicians. Greater satisfaction was significantly associated with better self-rated health and physical function, less emotional distress, and more social activity but was not related to physicians' health ratings, number of diagnoses, or cognitive function. Mean levels of satisfaction were also significantly different for patients of different physicians but not appreciably related to patients' sociodemographic characteristics. When patient sociodemographic characteristics were controlled for, the relations of health status variables to satisfaction were essentially unchanged. It was concluded that the key issues to be resolved are whether better health leads to greater satisfaction or vice versa, and, in either case, whether the relations are mediated by factors relating to the patient's experience of medical care.

Aged↗
PubMed1990

Age alters pulsatile prolactin release: influence of dopaminergic inhibition.

To determine the effect of age on pulsatile prolactin secretion, we examined prolactin pulse characteristics by cluster analysis in healthy young and old male subjects during the day and night. Pulsatile prolactin secretion was identified in all subjects during the day and night, and prolactin pulse frequency remains stable with age. Younger subjects had a significantly higher prolactin pulse amplitude, area, and peak interval during the night compared with older subjects. In contrast, daytime prolactin pulse characteristics were similar in young and old subjects. Because the major neuroregulator of prolactin is dopamine and because normal aging has been reported to be associated with reductions in hypothalamic dopamine content and effect, we determined whether the mechanism of altered day-night prolactin pulsatile secretion was due to changes in dopaminergic tone. We examined endogenous prolactin secretion after administration of the dopamine antagonist metoclopramide. Metoclopramide significantly increased mean serum prolactin concentration and prolactin pulse height and amplitude in all subjects during the day and night. However, net prolactin pulse amplitude after metoclopramide stimulation at night was significantly higher in older subjects compared with younger subjects. We conclude that prolactin pulse amplitude is blunted in elderly men at night and that daytime pulsatile prolactin secretion is unaltered by age in normal men. The mechanism for this alteration of nighttime prolactin pulsatile secretion in elderly men may be due to age-associated changes in dopaminergic regulation.

Adult↗
PubMed1989

Phenytoin-induced improvement in muscle cramping and insulin action in three patients with the syndrome of insulin resistance, acanthosis nigricans, and acral hypertrophy.

Phenytoin sodium has been used to treat muscle cramps of diverse causes, and is known to increase insulin sensitivity during long-term use. We have previously described a syndrome of insulin resistance, acanthosis nigricans, and acral hypertrophy with continual muscle cramping. The effect of 300 mg/d of phenytoin (Dilantin) on muscle cramping and carbohydrate economy was studied in three affected patients and four control subjects. Oral glucose tolerance tests, euglycemic insulin infusion studies, and monocyte insulin binding tests were conducted before and after phenytoin administration. All three patients had notable improvement in muscle cramps. In response to phenytoin, metabolic improvements were variable, with improvement characteristically better in patients with less severe baseline metabolic abnormalities. Patient 1, with the mildest degree of glucose intolerance, had decreased fasting insulin and blood glucose levels, improved glucose tolerance, and insulin-mediated glucose disposal, associated with an increase in monocyte insulin receptors. Patient 2 had reduced fasting plasma glucose and insulin levels and improved oral glucose tolerance, suggesting a beneficial effect on carbohydrate metabolism. Patient 3, with the most severely impaired carbohydrate economy, showed no metabolic improvement despite marked lessening of muscle pain. These clinical characteristics were unaffected in control subjects. We conclude that phenytoin is of value in the therapy of muscle cramps and glucose intolerance in patients with this syndrome.

Acanthosis Nigricans↗