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Biomedical subjects

D J Stott

Publications and source records attributed to D J Stott.

50 records · Page 3Linked to original sources

Evaluation of pre-admission screening of elderly patients accepted for major joint replacement.

Valuable orthopaedic operating time is frequently lost because patients are found to be medically unfit for surgery on admission. One hundred and forty seven consecutive patients aged 60 years or older, who had been accepted for major joint replacement and who lived within 15 miles of the Western Infirmary, Glasgow were screened at a preadmission clinic. The screening protocol had been agreed by orthopaedic and anaesthetic staff involved in major joint replacement surgery. Some 42 patients had medical illnesses which would have resulted in surgery being postponed and a further five had their surgery cancelled. Six patients passed fit for surgery at the pre-admission screening clinic were unfit for surgery on admission. Two patients in this group had their surgery cancelled. Using the guidelines suggested, pre-admission screening could be carried out by the patient's general practitioner (GP) or by a member of the medical staff when the patient attends the orthopaedic out-patient clinic. By following a simple protocol the amount of valuable operating time lost through unrecognised or poorly controlled medical illness could be greatly reduced. Pre-admission screening should result in more efficient use of scarce hospital resources and improved patient care.

Age Factors↗

Hemodynamic effects of a single moderate dose of alcohol in elderly subjects.

The effects of 0.5 g ethanol/kg body weight and of an iso-volumic control drink were compared in eight normotensive subjects aged 70-96 years. Blood alcohol concentration reached a mean (+/- SEM) maximum of 44.4 +/- 5.0 mg/dl at 50 minutes after the start of drinking. Compared to control, alcohol increased mean sitting and standing heart rates by 3.4 +/- 1.3 (p = .08) and 5.4 +/- 1.9 (p less than .05) beats/minute, respectively; mean venous haematocrit rose by 3.9 +/- 1.3% (p less than .05). There were no significant changes in sitting or standing systolic or diastolic blood pressures after alcohol compared to the control drink. A single moderate dose of alcohol has only minor haemodynamic effects in normotensive elderly subjects. The rise in heart rate after alcohol may be a reflex response that helps to maintain blood pressure in the face of reduced circulating plasma volume due to alcohol-induced diuresis.

Aged↗

Elderly patients with suppressed serum TSH but normal free thyroid hormone levels usually have mild thyroid overactivity and are at increased risk of developing overt hyperthyroidism.

The clinical and biochemical characteristics of 15 elderly patients with low levels of thyrotrophin (TSH) (< 0.1 mU/L) but normal free tri-iodothyronine (T3) and free thyroxine (T4) (group S) were compared with 10 euthyroid subjects (group E) and 10 hyperthyroid patients (group T). Free T3 and free T4 were significantly higher (p < 0.05) in group S (6.3 +/- 0.5 and 18.6 +/- 1.0 pmol/l, respectively) than in group E (4.6 +/- 0.3, 12.6 +/- 0.6). In common with elderly hyperthyroid patients (group T), patients in group S had few signs or symptoms of thyrotoxicosis, but the Wayne score (clinical index of hyperthyroidism) was higher in group S than in euthyroid subjects (p < 0.05). Thyroid microsomal, thyroglobulin or thyrotrophin receptor antibodies were common in group T (n = 9) but not in groups S (n = 2) or E (n = 1). This suggests a low prevalence of Graves' disease in group S compared to group T. Combined thyrotrophin releasing hormone (TRH; 200 micrograms i.v.) and gonadotrophin releasing hormone (GnRH; 100 micrograms i.v.) tests were performed; no cases of low TSH due to hypopituitarism were identified in group S. During a mean of 7.9 (4-12) months of observation TSH reverted to the normal range (> 0.2 mU/L) in 7 of 15 patients in group S; thyroid hormone concentrations rose above the normal range in four, however, only two patients required treatment for hyperthyroidism.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

Functional capacity and mental status of elderly people in long-term care in west Glasgow.

Functional capacity and mental status were assessed in 821 patients in long-term care in West Glasgow. In geriatric medical long-term care only five (1.3%) out of 387 patients were independent in activities of daily living (walking, transfers from bed and chair, dressing, toileting, urinary and faecal continence) and were not severely mentally impaired (AMT score greater than 6/10); in psychogeriatric care n = 6/143 (4.2%) in private nursing homes n = 6/66 (9.1%) and in residential care n = 100/235 (42.6%). Patients in geriatric medical care had a greater prevalence of immobility and urinary incontinence but less mental impairment than those in psychogeriatric care. Nearly all patients placed in geriatric medical or psychogeriatric care had major functional disability or mental impairment. The level of disability was less in private nursing than in geriatric medical care. Although 57% of those in residential care required some assistance or supervision in activities of daily living or had severe mental impairment, 86% were independent in walking and 83% were continent of urine. The implications of these findings for the provision of care for physically and mentally frail elderly are discussed.

Activities of Daily Living↗

Effects of short-term ketanserin treatment on the QT interval and vagal function in healthy subjects.

1. The serotonergic type-2 (5HT2) antagonist ketanserin was given in a dose of 40 mg twice daily for 3 days to eight healthy subjects in a double-blind placebo controlled randomized crossover study. 2. The QTc interval was prolonged slightly but significantly (P less than 0.01) by a mean of 29 +/- 7 milliseconds after ketanserin compared to placebo. 3. Ketanserin reduced both mean arterial pressure and heart rate (P less than 0.05), by 5.7 +/- 1.8 mmHg and 3.5 +/- 1.5 beats minute-1 respectively, when compared to placebo. 4. There was a tendency (not statistically significant) for cardiac vagal outflow to be reduced after ketanserin (assessed by the heart rate responses to standing, deep breathing and the Valsalva manoeuvre). 5. In healthy man, ketanserin causes prolongation of the QTc interval and a reduction in heart rate. These changes do not appear to be due to enhanced cardiac parasympathetic activity.

Adult↗

The effects of the 5 HT2 antagonist ritanserin on blood pressure and serotonin-induced platelet aggregation in patients with untreated essential hypertension.

We have given the selective 5 HT2 antagonist ritanserin in a dose of 10 mg twice daily for 4 weeks in a double-blind, randomized, placebo-controlled, parallel group study of 18 patients with untreated essential hypertension. The fall in single platelet count due to 5 HT-induced platelet aggregation was significantly reduced by ritanserin compared with placebo (p less than 0.05). There were no significant changes in supine or erect blood pressure or heart rate after ritanserin compared to placebo. Forearm blood flow, measured by mercury-in-strain gauge venous occlusion plethysmography, was not significantly altered by ritanserin. Ritanserin caused prolongation of the QTc interval by 41 (SEM 11) ms (p less than 0.05 compared to placebo) but had no detectable effect on QRS duration, features suggestive of Class III antiarrhythmic activity. These findings do not support an independent role of the 5 HT2 receptor in maintaining raised arterial pressure in essential hypertension.

Aged↗

The effects of the 5 HT2 antagonist ketanserin in adult atopic asthma.

We have studied eight adult atopic asthmatic patients in a randomized double-blind, placebo-controlled, cross-over trial in order to examine the effects of the 5 HT2 antagonist ketanserin on airways function (FEV1, FVC, V50(chi), and V25(pi]. Ketanserin did not significantly change resting bronchomotor tone. Treadmill exercise caused a similar maximal percentage fall in FEV1 after both drug [16.8 (3.7)%] and placebo [19.2 (4.2)%]; ketanserin did not significantly attenuate bronchoconstriction, measured over a 20-min period after exercise. These results suggest that 5 HT2 receptors do not play a major role in the control of resting bronchomotor tone or in exercise-induced bronchoconstriction in adult atopic asthmatic patients.

Adolescent↗

Effects of a single moderate dose of alcohol on blood pressure, heart rate and associated metabolic and endocrine changes.

1. The effects of a single moderate dose of alcohol on blood pressure, heart rate and associated metabolic and endocrine changes were studied in 10 healthy subjects and compared with those of an isocaloric glucose control drink. 2. Systolic blood pressure rose at 1 h after both alcohol and the control drink. Therefore this early change was not specifically due to alcohol ingestion. Subsequently, there was a tendency (not statistically significant) for supine and erect systolic blood pressure to be reduced up to 8 h after alcohol ingestion. There were no consistent late changes in blood pressure observed over 7 days after alcohol. 3. Alcohol caused a marked tachycardia in both supine and erect postures which persisted beyond the time of detectable blood alcohol levels. 4. Blood sugar rose by a similar amount after alcohol and the isocaloric glucose control drink, but peak plasma insulin levels were higher after the control drink. 5. Plasma sodium rose in keeping with alcohol induced water diuresis. No significant changes in plasma potassium or magnesium were seen after alcohol. 6. Compared with the control drink there was no evidence from measurements of circulating adrenaline, noradrenaline, cortisol, aldosterone or renin of activation of the sympathoadrenal axis, adrenal cortex or renin-angiotensin systems after alcohol.

Adolescent↗

Antihypertensive mode of action of ketanserin.

The mechanism of blood pressure reduction by ketanserin in hypertensive patients is still not fully understood. It can occur in the absence of evident alpha 1-adrenergic blockade. However, particularly with prolonged therapy, features of alpha 1 blockade appear. There are both similarities and differences between the pattern of effects caused by ketanserin and prazosin. A central mode of action of ketanserin contributing to the blood pressure reduction is not excluded. It appears unlikely, however, that inhibition of aldosterone secretion makes a substantial contribution to the antihypertensive effect of ketanserin in humans.

Adrenergic alpha-Antagonists↗

Does acute serotonergic type-2 antagonism reduce blood pressure? Comparative effects of single doses of ritanserin and ketanserin in essential hypertension.

We have studied the acute effects of the serotonergic type-2 (5-HT2) antagonists ketanserin and ritanserin given as single oral doses to patients with essential hypertension. Ketanserin has alpha 1-antagonist properties, whereas ritanserin is largely devoid of alpha 1-receptor binding affinity. Ketanserin (40 mg orally) caused a significant reduction (p less than 0.03) of sitting mean arterial pressure over the 8-h period following drug administration by an average of 15.4 +/- 3.2 mm Hg (mean +/- SEM) as compared to a reduction of 8.5 +/- 2.2 following placebo. In contrast, ritanserin had no significant effect on blood pressure compared to placebo; sitting mean arterial pressure was reduced by 9.0 +/- 2.6 and 10.8 +/- 1.8 mm Hg after administration of 10 and 20 mg, respectively, of ritanserin. There were no significant differences in pulse rate among placebo, ketanserin, or ritanserin phases. Ritanserin caused a reduction in the hostility score (p less than 0.05) as measured by the Multiple Affect Adjective Check List; ketanserin had no significant effects. The highly selective 5-HT2 antagonist ritanserin, given in a dose which caused measurable alteration of psychological function tests, had no acute effects on blood pressure. The acute antihypertensive effects of ketanserin are not caused by 5-HT2 antagonism alone, but are likely to be dependent on its alpha 1-antagonistic properties.

Adult↗

Treatment of essential hypertension.

While no consensus over the treatment of essential hypertension has been reached, three recent major trials offer guidance to the clinician. The results of these trials and the role of new and old drugs in the treatment of hypertension are discussed.

Adrenergic beta-Agonists↗

Specificity of the serotonergic antagonist ketanserin.

Ketanserin reduces blood pressure effectively, but without inducing tachycardia. Its precise mode of action is unclear but under some circumstances it attenuates the rise in blood pressure caused by infusion of the alpha 1-agonist phenylephrine, suggesting that it acts at least partly as an alpha 1-adrenoceptor antagonist. However, the specificity of this attenuation has been questioned. We have therefore examined the effects of ketanserin on the blood pressure and heart rate responses to angiotensin II (a vasoconstrictor agent largely devoid of alpha 1-agonist properties). The blood pressure response to infused angiotensin II, in contrast to that of phenylephrine, was not attenuated by ketanserin. Ketanserin appeared not to increase cardiac efferent parasympathetic activity. At a dose used in the treatment of hypertension, ketanserin produces alpha 1-antagonism in man, which may partly explain its antihypertensive effect.

Adult↗

Twice-weekly dosing for thyroxine replacement in elderly patients with primary hypothyroidism.

Seven female patients (mean age 86 years) with proven biochemical primary hypothyroidism were enrolled in a single-blind randomized crossover study, of standard daily versus twice-weekly thyroxine therapy, with each phase of one month's duration. The median daily dose of thyroxine was 100 micrograms (range 75-100 micrograms). Serum levels of thyroid hormones and thyrotrophin were very similar during twice-weekly thyroxine therapy to those during daily therapy and there were no statistically significant differences between trough and peak serum total triiodothyronine, free thyroxine, or thyrotrophin levels or systolic time intervals during twice-weekly thyroxine. Administration of thyroxine twice-weekly to elderly patients with primary hypothyroidism gives effective biochemical thyroid hormone replacement, with no evidence from the systolic time intervals of tissue thyrotoxicosis at expected peak thyroid hormone concentrations. Supervised twice-weekly thyroxine should be considered in patients with primary hypothyroidism who comply poorly with daily dosing.

Aged↗