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Biomedical subjects

J F Potter

Publications and source records attributed to J F Potter.

At least 91 records · Page 5Linked to original sources
PubMed1993

Repeatability and relationship between arterialized catecholamines and blood pressure in elderly subjects.

Little work has been conducted to assess repeatability and relation of arterialized plasma catecholamines to blood pressure in elderly subjects. We studied 19 untreated elderly patients with essential hypertension and 19 matched normotensives on two occasions one week apart. After prolonged supine rest, BP, pulse rate and arterialized plasma catecholamine levels were measured. Systolic (SBP) and diastolic (DBP) blood pressure, plasma adrenaline (A) and noradrenaline (NA) repeatabilities were similar for the hypertensive and normotensive groups. Mean supine pulse rate was significantly higher in the hypertensive group as were arterialized plasma A, but not NA, levels. For the whole group there was a significant univariate correlation between log plasma A and SBP (r = 0.53), DBP (r = 0.59) and pulse rate (r = 0.41). In keeping with previously published work in younger subjects these results indicate a possible role for adrenaline in the maintenance of raised blood pressure levels in elderly people.

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PubMed1993

Reproducibility of ambulatory and clinic blood pressure measurements in elderly hypertensive subjects.

OBJECTIVES: To compare the reproducibility of clinic and ambulatory blood pressure measurements in elderly hypertensive subjects. SUBJECTS: Twenty-two untreated elderly hypertensives, with a clinic systolic blood pressure (SBP) > 160 mmHg and/or diastolic blood pressure (DBP) > 95 mmHg, and a mean age of 76 years (range 66-86). METHODS: Following three supine clinic blood pressure readings the subjects underwent 24-h non-invasive ambulatory blood pressure monitoring, measurements being taken at 20-min intervals from 0700 to 2200 h and at 30-min intervals from 2200 to 0700 h. Measurements were repeated during a further visit at a median interval of 10 weeks (range 1-10 months). RESULTS: Daytime ambulatory SBP levels were 20 mmHg (95% confidence interval 14-27 mmHg, P < 0.001) lower than clinic SBP, although DBP values were similar. The mean 24-h ambulatory SBP and DBP reproducibility [assessed by the standard deviation of differences (SDD) between visits] was significantly better than that for mean clinic blood pressure (SBP 6.3 versus 17.4 mmHg, P < 0.001; DBP 4.8 versus 7.0 mmHg, respectively, P < 0.05). With daytime defined as 1000-1959 h, the SDD between visits was 12.4 mmHg for SBP and 8.3 mmHg for DBP, but with daytime defined as 0700-2159 h, the SDD fell to 6.0 mmHg for SBP and 4.8 mmHg for DBP, values almost identical to those obtained with full 24-h blood pressure monitoring. There was no difference in night-time blood pressure reproducibility, whether night-time was defined as 2400-0559 h or 2200-0659 h. CONCLUSIONS: Both 24-h and daytime ambulatory blood pressure monitoring significantly improve the reproducibility of blood pressure measurements compared with clinic blood pressure readings in elderly hypertensive subjects. Increasing the number of daytime blood pressure readings by 50% (from 30 to 45) reduced the variability of blood pressure measurement by 50%. Twenty-four-hour ambulatory blood pressure monitoring is of value in obtaining reproducible blood pressure measurements in elderly hypertensive subjects. However, more than 30 readings are needed during a daytime recording to significantly reduce variability compared with repeated clinic measurements, although night-time variability is not significantly affected if the number of readings is reduced to 12 over a 6-h period.

Age Factors↗
PubMed1993

Effects of moderate sodium restriction on clinic and twenty-four-hour ambulatory blood pressure in elderly hypertensive subjects.

OBJECTIVE: To assess the effects of 80 mmol/day reduction in dietary sodium intake on clinic and 24-h ambulatory blood pressure in elderly hypertensive subjects. DESIGN: Double-blind, randomized, placebo-controlled, crossover trial lasting 10 weeks, following a 4-week run-in period. SUBJECTS: Seventeen untreated subjects with essential hypertension [systolic blood pressure (SBP) > or = 160 mmHg and/or diastolic blood pressure (DBP) > or = 95 mmHg], mean age 73 years (range 66-79). INTERVENTIONS: Subjects had clinic blood pressure and 24-h urinary electrolyte excretion measured while on their normal diet. Following a 4-week run-in period on a reduced-sodium diet (80-100 mmol/24 h) subjects entered a 10-week crossover trial of 80 mmol/24 h sodium supplement or matching placebo while continuing on the reduced-sodium diet. MAIN OUTCOME MEASURES: The within-patient change in clinic and 24-h ambulatory blood pressures at the end of each intervention period. RESULTS: Mean urinary sodium excretion at the end of the run-in phase rose during the high sodium intake phase and was reduced significantly at the end of the low sodium intake phase. There was a significant reduction in clinic supine SBP between the high- and low-sodium phases. There was no significant change in standing SBP, supine or standing DBP or pulse rate between phases. There was a non-significant reduction in mean 24-h SBP and DBP on the low sodium intake. At the end of the low-sodium phase there was a significant increase in plasma renin activity and aldosterone levels, but no change in plasma electrolytes. CONCLUSIONS: Overall, moderate sodium restriction in elderly hypertensives resulted in a significant fall in clinic supine SBP only, although marked differences in intersubject responses were found. Moderate sodium restriction may be of benefit in only some elderly hypertensive subjects as part of a non-pharmacological regimen for blood pressure reduction.

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PubMed1993

Age-related differences in simultaneous interarm blood pressure measurements.

Simultaneous noninvasive blood pressure measurement were recorded bilaterally in 40 young and 40 elderly subjects. Overall interarm blood pressure (BP) differences for the elderly and young groups were similar, the absolute interarm differences being for systolic blood pressure (SBP) elderly: 4.2 mmHg (95% CI 3.1-5.3 mmHg); young 3.3 mmHg(2.6-4.1 mmHg); diastolic blood pressure (DBP) elderly 3.6 mmHg(2.8-4.4 mmHg), young 2.7 mmHg(2.0-3.3 mmHg). However, the range of interarm BP differences was wide. Four (10%) of the elderly had an interarm SBP difference > 10 mmHg compared to one (3%) of the young group. Interarm DBP differences > 8 mmHg were found in three (8%) of the elderly and in none of the young group. Although age does not affect mean interarm BP differences, clinically important interarm BP differences exist in both young and elderly subjects. Blood pressure should be measured in both arms of all patients at initial assessment to avoid potential problems with misclassification of blood pressure status.

Adult↗
PubMed1993

Blood pressure, plasma catecholamine and renin responses to caffeine in elderly hypertensives.

In young hypertensive patients, after a short period of abstention, caffeine ingestion has a significant pressor effect, although the acute cardiovascular responses have not been reported in elderly hypertensives. This study assessed the acute changes in BP, pulse rate, plasma renin activity (PRA) and arterialised plasma catecholamines after 250 mg of caffeine and matching placebo following 12 and 48 hours of caffeine abstention. After 48 hours caffeine abstention supine SBP was higher over the 120 minute study period following acute caffeine loading than following placebo (10 mmHg; 95% Cl 3-17 mmHg, P = 0.016) although the overall post-caffeine rise from baseline values was small (2 mmHg; -3 to 8 mmHg, P = 0.30). Similar differences were seen for supine DBP and standing SBP and DBP although pulse rate was unchanged throughout. After 12 hours abstention no acute pressor effect of caffeine was seen, in fact SBP fell over the study period (-5 mmHg; -10 to 0 mmHg, P = 0.05), and there was no difference between the caffeine and placebo phases. No change in plasma catecholamines or PRA values was found during any of the phases. These results suggest that in elderly hypertensives the pressor effect of caffeine (the equivalent of two to three cups of coffee) is small even after prolonged abstention. After the shorter abstention period, of the duration likely to be seen in clinical practice, no pressor response to caffeine was demonstrated. It is unlikely that acute caffeine ingestion has a significant effect on clinic BP measurements in elderly hypertensives who are regular caffeine consumers.

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PubMed1992

General practitioners' management of hypertension in elderly patients.

OBJECTIVE: To assess general practitioners' attitudes to the diagnosis and management of hypertension in elderly patients. DESIGN: Postal questionnaire to all general practitioners in Leicestershire. RESULTS: 360 of 451 general practitioners (80%) responded. 81% (292) reported rechecking an initially high blood pressure on two or three occasions before starting treatment, 56% (202) measured sitting blood pressure only, and just 28% (100) took sitting and standing levels. 36% (128) had no upper age limit for starting anti-hypertensive treatment; of the 58% (206) who did, the median was 80 (range 70-99) years. Blood pressure levels reported for starting treatment in patients aged 70-79 years were 180 (150-240)/106 (90-120) mm Hg. 34% of general practitioners (121) would not treat isolated systolic hypertension. The most popular first line treatment for an elderly hypertensive patient was a thiazide diuretic; only 17% of general practitioners (61) initially tried non-pharmacological methods. 34% (122) would continue anti-hypertensive treatment unchanged in the period immediately after stroke. CONCLUSIONS: The variation among general practitioners in the criteria for the measurement, diagnosis, and treatment of hypertension in elderly patients emphasises the need for clear management guidelines in this age group.

Adrenergic beta-Antagonists↗
PubMed1992

A prospective evaluation of the cumulative illness rating scale.

Assessment of overall physical health is an important yet little studied problem in geriatric research. The Cumulative Illness Rating Scale (CIRS) was among the first instruments that attempted to summarize the overall severity of illness based on clinical information. This study evaluated the CIRS in a prospective longitudinal study of 181 elderly (mean age +/- SD = 79 +/- 7.4) subjects undergoing comprehensive geriatric assessment in an outpatient unit. The CIRS was found to correlate negatively with activities of daily living (r = -0.49, p = 0.0001), instrumental activities of daily living (r = -0.34, p = 0.0001), patient morale (r = -0.30, p = 0.0001), and positively with days in hospital (r = 0.21, p = 0.0075) and number of medications (r = 0.31, p = 0.0001). Mean CIRS scores for subjects who died during follow-up were significantly higher than the scores for survivors (p less than 0.01). In logistic regression, CIRS was a significant predictor of death, yet it did not improve that prediction over information contained in measures of activities of daily living. In separate logistic analyses, CIRS and age predicted acute care hospital days during follow-up, while ADL or IADL predicted the use of nursing home services. Although the CIRS appears to be a reliable method of summarizing medical information and to have some external validity, in its present form it does not provide additional prognostic information.

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PubMed1992

Thiamine status of elderly patients with cardiac failure.

This study compared the thiamine status of 37 elderly patients admitted with cardiac failure (CF) with that of 35 unselected elderly patients with other diagnoses (Non-CF), and with that of 41 apparently healthy elderly people. The thiamine pyrophosphate effect (TPPE) on erythrocyte transketolase activity was used to estimate thiamine status. The prevalence of thiamine deficiency (TPPE greater than 19%) on admission in the CF and Non-CF groups was 13% and 29%, respectively. The TPPE of the CF group was significantly lower than that of the Non-CF group, and was not significantly different from that of the elderly control group. The results indicate that thiamine deficiency is not common in an unselected group of elderly inpatients with cardiac failure, but a potential benefit of thiamine supplementation in such patients cannot be ruled out.

Adult↗
PubMed1992

Altered epithelial lining fluid parameters in old normal individuals.

Pneumonia is a leading cause of morbidity and death in older patients, and immunosenescence is believed to contribute to their susceptibility. In order to investigate whether age-related changes occur on the epithelial surfaces of the lung, bronchoscopy and bronchoalveolar lavage (BAL) were performed without complication in 19 young (27.7 +/- 4.2 yrs), 6 middle-aged (49.8 +/- 3.5 yrs), and 8 old (74.1 +/- 4.3 yrs) normal, nonsmoking subjects. BAL was performed by instilling and retrieving five 20 ml aliquots of normal saline into three sites. The returns from the first aliquots (the bronchial sample) were analyzed separately from the returns from the subsequent aliquots (the distal sample). Lavage fluid cellularity was characterized and IgA, IgG, and albumin were measured by ELISA. Lavage fluid returns were lower in the elderly group and correlated with spirometric parameters. Significantly elevated numbers of neutrophils were recovered by the bronchial sample fluid from the old group. In contrast, no consistent difference in macrophage recovery by either the bronchial or distal sample was noted. In both the bronchial and distal samples, IgG, but not IgA or albumin, was elevated in the group of old subjects. Alterations occurring in BAL fluid with aging may reflect changes in local host defenses.

Adult↗
PubMed1992

Potassium supplementation reduces clinic and ambulatory blood pressure in elderly hypertensive patients.

OBJECTIVES: To determine the effects of potassium chloride 60 mmol/day supplementation on clinic and 24-h ambulatory blood pressure values in elderly untreated hypertensive patients. DESIGN: A double-blind randomized placebo-controlled crossover study lasting 8 weeks, following a 4-week run-in period. SETTING: Outpatient clinic in a district general hospital. PATIENTS: Eighteen untreated elderly hypertensive patients (mean age 75 years, range 66-79) with a systolic blood pressure of > or = 160 mmHg and/or a diastolic blood pressure of > or = 95 mmHg were recruited from the clinics of local general practitioners and from the current hospital outpatient department. Patients had not received any antihypertensive medication for at least 4 weeks before entry into the study. INTERVENTIONS: Before entry into the study, the daily dietary electrolyte intake of each individual was established and this was maintained during the run-in and intervention periods. Following a 4-week run-in period patients received potassium supplements or matching placebo, each for 4 weeks. MAIN OUTCOME MEASURES: The within-patient changes in clinic and 24-h ambulatory blood pressures at the end of each intervention period. RESULTS: After 4 weeks potassium supplementation compared with placebo there was a significant fall in supine clinic blood pressure, standing and 24-h ambulatory systolic blood pressure. There was no significant change in clinic standing diastolic blood pressure, 24-h ambulatory diastolic blood pressure or pulse rate. Plasma renin activity increased and body weight fell after potassium supplementation. Twenty-four-hour urinary potassium rose significantly, whereas urinary sodium excretion was unchanged. CONCLUSIONS: A 60-mmol daily supplement of potassium chloride reduces clinic and 24-h ambulatory blood pressure in elderly hypertensive patients.

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PubMed1992

Factors delaying hospital admission after stroke in Leicestershire.

BACKGROUND AND PURPOSE: Use of thrombolysis and acute treatments for cerebral infarction may require that acute stroke be treated as a medical emergency. To assess the factors influencing the time to admission in acute stroke, we conducted a prospective study of all such patients admitted to the hospitals in Leicester, UK, over a 12-month period. METHODS: Factors assessed were age, sex, time of stroke onset, stroke severity, home circumstances, and routes of admission. Initial between-group comparisons were made with the Mann-Whitney U test. The individual contribution of each of these variables was assessed with multiple linear regression analysis. RESULTS: An accurate time of stroke onset was identified in 374 (70%) of 535 registered patients (median age 77 [range, 29-98] years; 332 men, 203 women). Median time from onset to admission was 6 hours, with 25% of the patients arriving in less than 2.5 hours and 75% in less than 11.5 hours. Multiple regression confirmed that only admission through the bed allocation bureau (p less than 0.001), living alone (p less than 0.001), and nocturnal onset (p = 0.003) prolonged delay time. Despite patients over 70 years of age taking a median of 7 hours from onset to admission compared with 4 hours for those under age 70 (p less than 0.001), the effect of age appeared to be dependent on these three factors. Age, sex, level of consciousness, rural domicile, and place of admission did not influence the delay time independently. CONCLUSIONS: We have identified some of the factors affecting the hospital admission delay time for stroke. With the possible advent of effective early treatments for stroke, these factors will need to be addressed.

Adult↗
PubMed1991

Erythrocyte sodium, potassium and sodium fluxes with cell and subject ageing.

In young subjects erythrocyte sodium was lower in females than in males. In males juvenile erythrocyte sodium decreased with subject age whereas in females aged erythrocyte sodium increased with subject age. Therefore, the difference in erythrocyte sodium between young male and female subjects was not observed in the elderly. These differences in erythrocyte sodium appeared to be mainly due to differences in the sodium pump rate constant. In juvenile cells from young subjects the sodium pump rate constant was related to the ouabain sensitive sodium flux rate, but not in elderly subjects, suggesting disturbed control of cell sodium in the latter group. Juvenile erythrocytes had a higher potassium content in elderly than young subjects but this was mainly in the 'frail' hospitalised elderly and it decreased more rapidly with cell ageing. This could indicate more active erythrocytes entering the blood in elderly subjects and then ageing more rapidly. Differences between young and elderly subjects in erythrocyte sodium, potassium and sodium pump rate constant were more marked in the 'frail' hospitalised elderly.

Adult↗
PubMed1991

Effects of carbohydrate type on postprandial blood pressure, neuroendocrine and gastrointestinal hormone changes in the elderly.

Previous studies have demonstrated that blood pressure falls postprandially in fit elderly subjects, the greatest changes occurring after meals with a high carbohydrate content. To evaluate the influence of the type of carbohydrate on postprandial blood pressure, the effects of equivalent energy content (2.4 MJ) high complex (starch) and high simple (monosaccharide) carbohydrate meals were studied in seven healthy elderly subjects. Blood pressure, heart rate, autonomic function, plasma catecholamines, insulin and neurotensin levels were measured pre- and postprandially. Greater falls in supine and erect systolic blood pressure occurred after the high simple than the high complex carbohydrate meal (p less than 0.05). No differences were found in supine or erect diastolic blood pressure, heart rate or in any of the biochemical parameters measured between the meal types. It is concluded that a simple carbohydrate meal results in a greater postprandial fall in blood pressure than an equivalent energy complex carbohydrate meal in the elderly, although the mechanisms for these changes are unknown.

Aged↗
PubMed1991

The effect of caffeine on postprandial hypotension in the elderly.

In a double-blind, randomized trial the effects of caffeinated and decaffeinated drinks on postprandial hemodynamic and neurohumoral changes were studied in seven fit, elderly subjects after a standard 2.4MJ meal. There was a significant difference in supine postprandial systolic blood pressure between the placebo and caffeine phases (P less than 0.01); at 60 minutes, supine systolic blood pressure had fallen 14 mmHg [95% confidence interval (CI)-7 to-21 mmHg, p less than 0.01) after placebo, but was unchanged after caffeine (+9 mmHg, CI 0 to 18 mmHg, NS]. Similar differences between placebo and caffeine were seen in erect systolic and diastolic blood pressure (P less than 0.01), although orthostatic tolerance was maintained throughout each study period. Postprandial plasma noradrenaline levels were higher (P less than 0.02) and the increase greater (P less than 0.02) after caffeine than after placebo. Caffeine administered at the end of a standard test meal prevents the postprandial fall in blood pressure in fit, elderly subjects. The clinical relevance of this finding has yet to be determined, but it may offer a simple remedy for patients with symptomatic postprandial hypotension.

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PubMed1991

Low Body Mass Index in demented outpatients.

In order to determine the association between dementia and low body weight in outpatients, Body Mass Index (BMI) was evaluated prospectively in 346 frail elderly outpatients presenting for comprehensive geriatric assessment. Patients were categorized into four groups (cognitively intact, dementia of the Alzheimer's type (DAT), other dementia, and patients with depressive symptoms). Patients were assessed for severity of dementia by the Clinical Dementia Rating scale. Differences between groups for various clinical parameters were evaluated using an analysis of variance and Duncan's Multiple Range Test. Patients with dementia, regardless of etiologic type or severity, and patients with depressive symptoms had BMI's greater than or equal to 10% lower than the cognitively intact patients. BMI was positively correlated with Instrumental Activities of Daily Living (IADL) but not Activities of Daily Living (ADL) or Mini-Mental State Exam (MMSE) score. Low BMI was not associated with increased physical illness. In fact, in the subset of patients with DAT, lower BMI correlated with significantly lesser amounts of comorbid physical illness. Finally, compared to cognitively intact outpatients, patients with DAT appeared to be physically healthier despite their having a lower BMI. These results suggest an association between dementia and low BMI. On the other hand, the presence of comorbid physical illness, a common focus of evaluation in these patients, was not more common in those patients with lower BMI's.

Aged↗
PubMed1991

Factors determining the acute pressor response to alcohol.

The pressor response to acute alcohol loading is variable and the factors influencing it are unknown. Data from 34 standardized alcohol loading studies were analysed to try to identify any factor(s) that might predict the pressor response to oral alcohol. The maximum blood pressure rise following an acute alcohol load was assessed for each subject over a 4 hour period. Age, weight, recent alcohol intake, baseline blood pressure, pulse rate and serum gamma glutamyl transferase levels were entered, as the independent variables, into a multiple linear regression analysis with the maximum blood pressure response as the dependent variable. Alcohol consumption in the week prior to the study predicted the systolic blood pressure pressor response to acute alcohol loading. None of the independent variables entered had any predictive value for diastolic or mean arterial blood pressure response.

Adult↗