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Biomedical subjects

J Webster

Publications and source records attributed to J Webster.

At least 199 records · Page 11Linked to original sources
PubMed1989

Circulating human T and B lymphocytes express the p55 interleukin-2 receptor molecule (TAC, CD25).

Using a highly sensitive immunofluorescence procedure 15-45% of blood lymphocytes from normal human donors can be shown to react with anti-TAC (CD25) monoclonal antibodies. The standard procedure for indirect immunofluorescence does not allow the detection of these CD25-positive cells. Ten healthy adults were tested, and all showed a population of positive cells. Three donors have been tested more than once, and have given consistent results. Three different CD25 antibodies were used, again with consistent results. Double-marker studies showed that the positive cells included B cells, as well as CD4-bearing and CD8-bearing T cells.

Antibodies, Monoclonal↗
PubMed1989

Clinical efficacy of xamoterol, a beta 1-adrenoceptor partial agonist, in mild to moderate heart failure. U.K. Xamoterol Study Group.

The clinical efficacy of xamoterol, alpha beta 1-adrenoceptor partial agonist, was determined in a multicentre double-blind, randomized, parallel group study of 240 patients with mild to moderate heart failure. At entry, 62% of patients were receiving diuretics (thiazides, or loop diuretics at a dose no greater than the equivalent of 80 mg of frusemide); 32% were taking nitrate formulations and 14% digoxin for control of atrial fibrillation. Assessments were carried out after a 1-week placebo run-in and after 3 months of treatment with either xamoterol or placebo. 198 patients completed the study of whom 186 had valid exercise tests. Mean exercise duration increased by 7% after placebo and by 19% after xamoterol during a progressive treadmill exercise protocol. Xamoterol significantly reduced peak exercise heart rate compared with placebo. Subjectively, there was improvement in breathlessness on the visual analogue scale after treatment with xamoterol compared with placebo, but no change in fatigue. We conclude that xamoterol produces sustained improvement in symptoms and exercise duration in mild to moderate heart failure.

Adrenergic beta-Agonists↗
PubMed1989

Linear cardiac output in borderline and sustained hypertension.

We assessed the relative contributions of raised cardiac output and increased peripheral resistance to elevation and lability of blood pressure in patients with borderline and sustained hypertension. Ninety-five untreated patients were admitted to hospital for assessment. Using Doppler ultrasound, linear cardiac output was measured as minute distance on the day of admission and 24 h later; blood pressure was measured at the same times, enabling calculation of linear resistance (analogous to peripheral vascular resistance). In sustained, but not borderline, hypertension linear resistance was increased at the first measurement (+ 36%, P less than 0.001), but mean minute distance did not differ significantly from normal in either group. Between the first and second measurements in borderline and sustained hypertension there were significant falls of mean blood pressure (-9%, P less than 0.001 and -4%, P less than 0.01). In borderline, but not sustained, hypertension there was an associated fall of linear resistance (-11%, P less than 0.05); in neither group was there a significant change of minute distance. Both elevation and lability of blood pressure in borderline and sustained hypertension are due more to changes of peripheral resistance than to changes of cardiac output.

Adolescent↗
PubMed1989

Evaluation of a long acting formulation of nicardipine in hypertension by clinic and home recorded blood pressures and Doppler aortovelography.

1. A novel formulation of nicardipine (50% standard (short acting), 50% sustained release) was evaluated in mild hypertension in a double-blind, randomized, placebo-controlled study, using clinic measurements (Hawksley) augmented by home recorded blood pressures (Copal UA 251). 2. Nicardipine 60 mg twice daily for 28 days produced a highly significant reduction in sitting blood pressure compared with placebo both pre dose (mean difference 17/8 mm Hg) and 2 h post dose (mean difference 34/26 mm Hg). 3. Home recordings confirmed the hypotensive effect and also revealed a consistent 'peak' effect between 2-4 h after dosing (mean difference 32/22) mm Hg). 4. Doppler aortovelography at 2 h post-dose showed a significant increase in in stroke and minute distance (linear analogues of stroke volume and cardiac output respectively) compared with placebo. The increase in stroke distance was linearly related to change in plasma concentration of nicardipine. 5. Of the 14 patients enrolled in the study, nine experienced troublesome adverse effects on nicardipine (headaches, facial flushing, palpitations, ankle oedema) and two of these were unable to complete the study as a result. 6. This formulation of nicardipine, in the fixed dosage used in this study, is characterized by an effective antihypertensive action but also by an unacceptable adverse effect profile, presumably due to an excess of its 'short acting' component.

Blood Pressure↗
PubMed1989

Does a selective 5-hydroxytryptamine antagonist (ICI 169, 369) lower blood pressure in hypertensive patients?

1. The effect of single doses (10, 30 and 50 mg) of a selective 5-HT2 receptor antagonist, ICI 169, 369, on blood pressure, heart rate and the electrocardiogram was studied using a double-blind, placebo-controlled, within subject design in hypertensive patients. 2. ICI 169, 369 did not reduce blood pressure or increase QT interval as has been reported with ketanserin. This suggests that it is the other properties of ketanserin which are responsible for its antihypertensive effect. 3. Plasma concentrations of AUC for ICI 169, 369 were low. This is consistent with low bioavailability due to extensive first pass metabolism. 4. ICI 169, 369 was well tolerated and none of the symptoms reported by the patients was thought to be drug related.

Adult↗
PubMed1989

Flecainide and cardiac dysrhythmias during dental extraction under anaesthesia.

In a randomized double-blind study, either oral flecainide acetate 400 mg (a Class IC anti-dysrhythmic drug) or placebo was given in two divided doses 12 and 2 h pre-operatively to 38 patients undergoing outpatient molar extractions under halothane anaesthesia. The ECG was continuously monitored from the patients' arrival at the out-patient theatre until discharge, using a two-channel ambulatory magnetic tape recorder. There was a much lower incidence of ventricular dysrhythmias in patients who received flecainide (22%) than those who received placebo (75%) (P less than 0.05). In addition, dysrhythmias were both more severe and more prolonged in the untreated group, prompting treatment with intravenous practolol in seven patients (35%). Flecainide was well tolerated and no adverse effects were reported.

Adolescent↗
PubMed1989

Computer-assisted shared care: the Aberdeen Blood Pressure Clinic.

A computer-assisted shared-care follow-up system, the patient record system, was used to follow up more than 3300 patients referred for assessment of hypertension. The patients are being followed up in collaboration with more than 250 general practitioners either in the hospital or in general practice, according to the assessment at each visit. The follow-up incorporates measures to control blood pressure below arbitrary target levels. Clinically important information is shared between doctors and between doctors and patients in order to highlight patients at risk, poor control of blood pressure, drug-host and drug-drug interactions and adverse reactions and to optimize the process and outcome of care.

Ambulatory Care Information Systems↗
PubMed1988

Endotoxins in culture medium for human in vitro fertilization.

Endotoxins were detected in a few batches of culture medium during the authors' human in vitro fertilization program. Two distinct levels of endotoxins were assayed: greater than 1 ng/ml and less than 1 ng/ml. The source of endotoxin was traced to culture media obtained from a reputable manufacturing company. The incidence of fertilization per patient was not significantly affected by the presence of endotoxins, but fertilization assessed on the overall number of oocytes was significantly reduced (53%) when endotoxin levels were greater than 1 ng/ml compared with an assay negative for endotoxins (66%) (P = 0.047). The percentage of oocytes cleaving after the observation of two pronuclei was not significantly different, but the degree of fragments observed in the conceptus was significantly more severe if the endotoxin level reached 1 ng/ml. In this investigation, the incidence of pregnancy was 8% when the endotoxin level was greater than 1 ng/ml, 30% if less than 1 ng/ml, and 32% if no endotoxins were detected. This study suggests that, although endotoxins may be present in the culture medium at a deleterious level of at least 1 ng/ml, fertilization and cleavage will be obtained, but there will be a significant increase in the incidence of conceptuses with cytoplasmic fragments; this may result in a reduction in the incidence of pregnancy.

Cells, Cultured↗
PubMed1988

Split course radiation therapy for adenocarcinoma of the pancreas.

Ninety-five patients with biopsy proven adenocarcinoma of the pancreas were treated with split course radiation therapy. Fifty-five patients had disease confined to the peripancreatic tissues and lymph nodes. Forty patients had metastatic disease. The intended radiation therapy scheduled consisted of two courses of 25 Gy in 10 fractions each followed by a 3 to 4 week rest period. Depending on the response and the patient's clinical status, another 10 Gy in 5 fractions was administered as a final boost. The median survival in patients with metastatic disease was 3 months and the median survival in patients with localized disease was 8 months. Twenty-seven of the fifty-five patients with localized disease received chemotherapy (5 FU or FAM) combined with radiotherapy. There was no significant difference in median survival between the patients treated with radiation alone and those with combined radiation and chemotherapy. The median survival for patients with localized disease receiving 25, 50, and 60 Gy were 3, 7, and 12 months respectively. After a dose of 50 Gy in 20 fractions, CT scan showed no evidence of tumor in 6%, smaller tumor size in 31%, stable tumor size in 41%, and tumor growth in 22% of patients. The split course radiation therapy was well tolerated and no late complications were detected. The medical and economic advantages of using split course radiation therapy and in using CT scan response to plan boost therapy are discussed.

Adenocarcinoma↗
PubMed1988

Once-daily amlodipine in the treatment of mild to moderate hypertension.

The antihypertensive efficacy of once-daily amlodipine was studied in a group of 30 patients with mild to moderate hypertension in a double-blind, placebo-controlled, parallel-group study. The dose range of amlodipine was 2.5-10.0 mg daily adjusted every 2 weeks for a total treatment period of 8 weeks. Amlodipine produced a significant reduction in blood pressure compared with placebo, the mean difference between baseline and 8 weeks (corrected for placebo effect) being 16/12 mm Hg supine, 14/4 mm Hg standing. Blood pressure returned to baseline values during a terminal 4-week washout period with placebo. There were no significant effects on heart rate. Two patients experienced slight ankle edema while receiving amlodipine 10.0 mg daily but the active drug was otherwise well tolerated.

Adult↗
PubMed1988

The effect of age and cardiac failure on xamoterol pharmacokinetics.

1. Xamoterol is a cardioselective beta-adrenoceptor partial agonist which may have a role in the management of cardiac failure. Excretion is mainly by the renal route. 2. The kinetics of a single 200 mg oral dose of xamoterol were studied in eight elderly (age 67-82 years) volunteers, eight young (age 21-43 years) volunteers; eight patients with mild to moderate cardiac failure and eight age and sex matched controls. 3. Elderly volunteers had a significantly longer time to reach peak concentration (mean +/- s.e. mean 2.1 +/- 0.2 vs 1.1 +/- 0.1 h) and elimination half-life time (27.0 +/- 2.8 vs 16.4 +/- 3.1 h) compared with young volunteers. The renal clearance of xamoterol was lower in the elderly (115 +/- 12 vs 185 +/- 19 ml min-1) and showed a significant correlation with creatinine clearance (r = 0.85, P less than 0.001). 4. There was no significant difference in any of the pharmacokinetic parameters measured in patients with cardiac failure compared with healthy age and sex matched controls. 5. These results suggest that the maintenance dose of xamoterol could be reduced in elderly patients in relation to impairment of renal function.

Adrenergic beta-Agonists↗
PubMed1988

Effects of the beta 2-adrenoceptor antagonist ICI 118,551 on blood pressure in hypertensive patients known to respond to beta 1-adrenoceptor antagonists.

1. The selective beta 2-adrenoceptor antagonist ICI 118,551, 50 mg orally given thrice daily, did not lower blood pressure in hypertensive patients known to respond to therapy with atenolol or propranolol. 2. This dosage regimen resulted in a small decrease in supine heart rate which might represent partial beta 1-adrenoceptor antagonism by ICI 118,551. 3. The results suggest that beta 2-selective antagonism does not play a role in the hypotensive action of beta-adrenoceptor antagonists.

Adrenergic beta-Antagonists↗
PubMed1988

An evaluation of transcutaneous electrical nerve stimulation for pain relief in labour.

The effectiveness of transcutaneous nerve stimulation (TENS) for pain relief in labour was evaluated by randomizing 280 patients in early labour into 2 groups. Inoperative sham machines were applied to patients in the control group and active units to those in the test group. Neither patients nor attending labour ward staff were aware of which group the patient was in. The intensity of low back pain and abdominal pain was assessed by the patient each hour on a visual analogue pain scale. Each patient served as her own control by switching off the machine for 2 contractions every hour and then recording the intensity of pain. The amount of conventional analgesia each patient received was recorded by labour ward staff. There was no difference in the intensity of pain recorded by each group. Nor was there any difference between the 2 groups in the change of pain experienced when the machine was switched off. Moreover there was no difference in the amount of other analgesia required. Some differences were found when those with little low back pain were excluded from the study. We conclude that TENS is ineffective as a routine method of pain relief in labour. It is likely to benefit only those with severe back pain and then only to a modest degree.

Electric Stimulation Therapy↗
PubMed1988

Post-caesarean wound infection: a review of the risk factors.

In a prospective study of 1,546 patients delivered by Caesarean section a wound infection developed in 146 (9.4%); the rate was significantly higher in clinic patients (15.8%) compared with private patients (6.0%). Elective operations resulted in a lower incidence of wound infection (7.9%) than emergency operations (12.3%). Other factors significantly associated with postoperative wound infection were: the number of vaginal examinations before surgery (p less than 0.05), duration of operation (p less than 0.005), vertical skin incision (p less than 0.05) and category of surgeon (p less than 0.001). In 56 patients for whom a past history was available, there was a record of a wound infection in 31 (55%). Clinic patients were over-represented in all situations predisposing to wound infection.

Anti-Bacterial Agents↗
PubMed1988

Angiotensin converting enzyme inhibitors may cause renal impairment in diabetes mellitus.

Angiotensin converting enzyme (ACE) inhibitors have been recommended for the treatment of diabetic nephropathy. However, it should be remembered that diabetic patients may also develop atheromatous renal artery stenosis. In such patients ACE inhibitors may have adverse effects on renal function. Careful investigation and monitoring is essential when ACE inhibitors are used in diabetes.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1988

Relation between energy expenditure and body composition in man: specific energy expenditure in vivo of fat and fat-free tissue.

The relationship between energy expenditure and body composition, in terms of fat and fat-free masses, has previously been described by a variety of predictive regression equations with parameters devoid of physiological content. We present here results obtained by calculating the specific energy expenditure, ie, the energy expenditure per unit of mass, of fat and fat-free tissue on the basis of measurements of the total energy expenditure (EE), the masses of fat (FM), and fat-free (FFM) tissue using the following simple model: EE = k1.FM + k2.FFM where k1 and k2 are the specific energy expenditures of fat and fat-free tissue, respectively. The results of observations on 104 women at rest yielded values for k1 and k2 of 0.31 and 1.35 watts/kg of fat and fat-free mass, respectively, with standard errors of estimate of 0.074 and 0.052 watts/kg, respectively. Analysis of several series of measurements, from other sources and on smaller samples of subjects, yielded similar values at rest but with larger standard errors of estimate. Data from subjects performing varying amounts of work in 24-h measurements showed, as expected, larger values for both tissues. The results explain to a very large extent the well-established relation between resting metabolic rate and body weight, ie, a linear relation with a non-zero intercept. The results also offer a clear-cut explanation for the well known difference in energy expenditure between men and women with the same body weight.

Adipose Tissue↗