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Biomedical subjects

S A Bowcock

Publications and source records attributed to S A Bowcock.

At least 19 recordsLinked to original sources
PubMed1989

Reflex sympathetic dystrophy (algoneurodystrophy): temperature studies in the upper limb.

The temperature response of the hands to mild cold stress (20 degrees C for one minute) has been measured in 20 normal subjects, 20 patients with reflex sympathetic dystrophy (RSD) and 10 patients with chronic upper limb pain (CULP) of uncertain origin. The results of RSD and CULP groups were significantly (p less than 0.05) different from normal but were indistinguishable. For each patient, 11 variables obtained from the thermal stress test were compared with the normal range. Ten of the RSD group and seven of the CULP group had four or more abnormal variables and were considered to have a thermoregulatory abnormality. The thermal stress test is useful in the objective assessment of RSD. It is non-invasive, patient acceptable and reproducible.

Adult↗
PubMed1987

Peripheral vascular effects of beta-adrenoceptor blockade: comparison of two agents.

1. The effects of atenolol (100 mg), a beta 1-adrenoceptor blocker, and bevantolol (200 mg) were compared on heart rate, blood pressure, lung function and on the peripheral circulation in normal volunteers before and after isoprenaline infusion. Recordings were obtained 2 and 24 h following a single dose and 24 h after continuous dosage for 7 days. 2. The effect of atenolol on the blockade of beta-adrenergic stimuli, as measured by the ability to reduce isoprenaline-induced tachycardia, was greater than that of bevantolol. Though both drugs achieved a similar reduction in systolic pressure there was a significantly greater reduction in diastolic pressure with bevantolol. The lung function tests gave similar results to those with other beta-adrenoceptor blockers. 3. Atenolol produced a fall in peripheral blood flow consistent with unopposed peripheral alpha-adrenoceptor stimulation. The effect of bevantolol differs from that of atenolol, an initial fall in peripheral blood flow being followed by a rapid recovery to baseline or greater. This effect may be due to partial alpha-adrenoceptor agonist activity.

Adrenergic beta-Antagonists↗
PubMed1985

Cold sensitivity in essential hypertension: the effect of beta- and combined alpha- and beta-blockade.

The presence of cold sensitivity was investigated in three groups of patients; untreated hypertensives and hypertensives treated by a beta-adrenoceptor blocker (propranolol) or by a combined alpha- and beta-adrenoceptor blocker (labetalol) at two ambient temperatures. At a comfortable ambient (24 degrees C) one-third of the untreated and those treated with beta-blockade only showed cold sensitivity as compared with 16% of patients on the combined therapy. Under conditions of mild cold stress (20 degrees C) cold sensitivity increased in frequency in all three groups, more than half of the untreated and beta-blocked patients were affected and greater than one-third of those with alpha- and beta-blockade. These findings indicate that in the general population of hypertensives treatment with beta-adrenoceptor blockade alone may have little effect on the peripheral vasculature and that a useful degree of protection may be provided by therapy which blocks both receptors.

Adrenergic alpha-Antagonists↗
PubMed1985

Transcutaneous oxygen tension as an index of maturity in hypertrophic scars treated by compression.

Sixteen patients undergoing compression treatment for scar hypertrophy were included in a study to evaluate physical indices of scar maturity. The results show that while thermographic measurements of scar temperature were not clinically valuable, rising levels of transcutaneous oxygen tension in treated scars correlated well with a reduction in scar thickness assessed both clinically and by ultrasound. It is postulated that low levels of tcpO2 in immature scars result from low oxygen diffusibility through scar tissue rather than from rapid metabolic consumption of oxygen by scar tissue.

Adolescent↗
PubMed1985

Photoplethysmography of the distal pulp in the assessment of the vasospastic hand.

A procedure for assessing the peripheral vasculature and a new technique for determining the characteristics of the a.c. (arterial) photoplethysmographic (PPG) waveform are described. Comparing 12 normal female volunteers and 12 female patients with Raynaud's phenomenon, PPG amplitude is as good as the results of a standard thermographic test in distinguishing between the groups. The limb arterial flow measured by strain gauge plethysmography (SPG) and the timing of features in the PPG waveform showed differences between the groups, which did not reach statistical significance. The rise time of the PPG waveform, however, was found to be correlated with age independently of vasospasticity.

Adult↗
PubMed1985

CL115,347, an analogue of prostaglandin E2. Peripheral circulatory effects of single ascending doses administered transdermally in normal subjects and in patients with Raynaud's phenomenon.

The beneficial effects of intra-arterial or intravenous infusion of the prostanoid products of anachridonic acid, PGE and prostacyclin (PGI2) are well documented. More recently an analogue of PGE2, (CL 115,347, American Cynamid Co.) has become available. This substance is absorbed transdermally from a patch placed on the skin. In a placebo-controlled trial the vasodilatory effect of single incremental dosage, 500 mcg, 1000 mcg and 1500 mcg, was measured in a temperature-/humidity controlled laboratory in normal subjects and in patients with primary and secondary Raynaud's phenomenon. The optimal dosage proved to be 1000 mcg; the effect may last for 84 hours; higher dosage may be associated with a "steal" phenomenon.

Administration, Topical↗
PubMed1984

A double blind trial of UK-38,485, an orally active thromboxane synthetase inhibitor, in the treatment of Raynaud's syndrome.

Ten patients with moderate to severe Raynaud's syndrome were recruited into a four week randomised double blind crossover study to compare the efficacy of UK-38,485 50 mg, a new thromboxane synthetase inhibitor with that of placebo. With the doses used there was no significant difference between the two treatment periods in the number, severity and duration of ischaemic attacks, the mean hand temperatures, forearm and digital blood flow and red blood cell rheology.

Adult↗
PubMed1981

Chlorpropamide alcohol flush and circulating met-enkephalin: a positive link.

Chlorpropamide-alcohol flushing may be due to sensitivity to endogenous opiates. To investigate this possibility the plasma met-enkephalin and beta-endorphin responses to sherry with and without chlorpropamide were studied in six patients with non-insulin dependent diabetes and in six normal subjects. After chlorpropamide all patients showed a rise in met-enkephalin concentrations from a basal level of 50 +/- 7.2 ng/l to a peak of 75 +/- 8.1 ng/l (p less than 0.001). In contrast, before chlorpropamide treatment was started met-enkephalin values did not change after alcohol. No significant changes in beta-endorphin values were observed. In six normal subjects pretreated with chlorpropamide the met-enkephalin concentration also rose from a basal level of 72 +/- 15 ng/l to a peak of 103 +/- 9.4 ng/l (p less than 0.002). Again, the met-enkephalin rise was not observed after placebo. Neither beta-endorphin concentrations nor facial temperature changed significantly. These data suggest that endogenous opiates may be implicated in CPAF. Furthermore, this is the first study in which a significant change in circulating met-enkephalin values has occurred.

Chlorpropamide↗
PubMed1981

Detection of immune complexes in systemic sclerosis and Raynaud's phenomenon.

Phagocytosed immune complexes in polymorphonuclear leukocytes of nineteen patients with Raynaud's phenomenon were detected by scoring the cells for IgG and C3 inclusions. Parallel estimations of circulating immune complexes were made by liquid phase C1q binding and polyethylene glycol (PEG) precipitation methods. The results were compared with the degree of cold stress-induced vasospasm measured by quantified infra-red thermography. Thirteen of nineteen patients with Raynaud's phenomenon compared with only one of seventeen normal controls showed significantly elevated levels of phagocytosed IgG. The correlation of IgG and C3 scores for individual patients was high and the IgG and C3 scores correlated well with the thermographic assessment of the severity of the Raynaud's phenomenon. Two of the patients had elevated levels of circulating immune complexes detectable by raised levels of C1q binding, four patients had raised IgG and three patients raised IgM complexes detectable by PEG precipitation. None of the controls had elevated levels of circulating immune complexes detectable by either method. There was no correlation between the levels of circulating and phagocytosed immune complexes.

Antigen-Antibody Complex↗
PubMed1981

Dorsal column stimulation in multiple sclerosis: effects on bladder, leg blood flow and peptides.

9 patients with bladder disorder secondary to multiple sclerosis (MS) were treated by dorsal column stimulation (DCS). Detailed urodynamic tests were performed and leg blood flow was assessed on repeated occasions. Cerebrospinal fluid (CSF) met-enkephalin levels were estimated before and during DCS. The chief effect of DCS was improved urinary flow associated with reduced sphincter tone and lessened detrusor instability maximal at the 6th or 7th day of continuous stimulation. Considerable fluctuation in leg blood flow occurred unrelated to activation of the stimulator. No obvious change in CSF met-enkephalin levels took place, but it is suspected that the mode of action of DCS in via certain peptide hormones.

Electric Stimulation Therapy↗
PubMed1978

After-exercise thermography for predicting postoperative deep vein thrombosis.

After-exercise thermography of the legs was carried out on 50 patients before undergoing major abdominal surgery (group 1) and on 59 patients before elective hip surgery (group 2). The incidence of postoperative deep vein thrombosis (DVT)--diagnosed by the 125I-fibrinogen uptake test in group 1 and phlebography in group 2--was significantly higher in patients whose after-exercise thermogram (AET) had been abnormal. Out of 19 patients in group 1 and 30 in group 2 with a normal AET, two and nine repsectively developed postoperative DVT. Among patients with a unilaterally abnormal AET the incidences were 12 out of 19 patients in group 1 and five out of nine in group 2. The incidences among patients with a bilaterally abnormal AET rose to 11 out of 12 patients in group 1 and 15 out of 20 in group 2. Preoperative after-exercise thermography is a simple, objective test that identifies patients at high risk of developing postoperative thromboembolic disease.

Abdomen↗
PubMed1977

Intravenous lignocaine in prevention of deep venous thrombosis after elective hip surgery.

Intravenous lignocaine is a possible means of preventing deep venous thrombosis (D.V.T.) after elective hip surgery. In 14 control patients the total incidence of D.V.T. was 78%, with a 57% incidence of thigh-vein thrombosis. In 14 patients treated at random with intravenous lignocaine during the first 6 postoperative days, there were only 2 calf-vein thrombi (14%; P less than 0-005). In a further 14 cases treated consecutively there were 4 unilateral calf-vein thrombi. No thrombi originated in the thigh veins (P less than 0-001). After intravenous lignocaine was stopped the total incidence of D.V.T. in the 28 patients rose to 53% with a 21% incidence of thigh-vein thrombi between the 7th and 14th postoperative days. There was no significant difference in postoperative coagulation and fibrinolytic activity between control and treated patients, and blood loss and transfusion requirements were similar. Immediate or delayed hypersensitivity reactions to lignocaine were not observed. The results support the view that damage to the vessel wall may be the initial event in the formation of a venous thrombus.

Adult↗
PubMed1977

Failure of orally administered hydroxychloroquine sulphate to prevent venous thromboembolism following elective hip operations.

In a double-blind, randomized trial of orally administered hydroxychloroquine sulphate in the prevention of venous thromboembolism after elective surgery on the hip, the drug or a placebo was given to fifty consecutive patients. Therapy was commenced on the day before the operation and continued for fourteen days. The diagnosis of deep venous thrombosis was made by daily thermographic scanning of the legs and confirmed by phlebography. The diagnosis of pulmonary embolism was made by perfusion lung scanning. No significant difference in the incidence of thromboembolism was found between treated and control groups. The results provide evidence that substances which reduce the incidence of thromboembolism in general surgery may not be effective in operations on the hip.

Administration, Oral↗