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Biomedical subjects

M J Butler

Publications and source records attributed to M J Butler.

33 records · Page 2Linked to original sources
PubMed1977

Plasma catecholamine concentrations during operation.

Plasma catecholamines have been measured before, during and after operation in 40 patients undergoing elective major abdominal surgery and in 12 patients during open heart surgery. Plasma concentrations did not increase during abdominal surgery and showed only small increases during cardiopulmonary bypass. It appears that it is not possible to assess individual intra-operative sympatho-adrenal responses to surgical trauma by measurement of plasma catecholamine concentrations because of the efficiency of catecholamine uptake mechanisms.

Abdomen↗
PubMed1976

The adrenergic response to surgery involving cardiopulmonary bypass, as measured by plasma and urinary catecholamine concentrations.

Plasma and urinary catecholamine concentrations have been measured in 13 patients undergoing cardiac surgery involving cardiopulmonary bypass. The large and progressive increase in plasma catecholamines during bypass reported in previous studies has not been confirmed, and this may be a result of improvements in surgical, anaesthetic and perfusion techniques. The interpretation of urinary findings was complicated by the finding of a positive correlation between catecholamine excretion and urine flow-rate. The findings suggest the need to modify current concepts of the adrenergic response to cardiac surgery and bypass, and question the validity of measuring the urinary catecholamine concentration as an index of stress in these circumstances.

Adult↗
PubMed1976

The coagulation and fibrinolytic response to splenectomy.

The responses of the coagulation and fibrinolytic systems in nine patients with Hodgkin's disease undergoing splenectomy and lymph node mapping have been compared with those in nine patients undergoing elective upper abdominal operation for benign conditions. Differences have been noted in base line levels of fibrinogen, prothrombin, partial thromboplastin time and euglobulin lysis time. Platelet count increases were exaggerated following splenectomy, but other parameters of coagulation activity behaved similarly in the two groups. There is no evidence from this study to support the suggestion that blood coagulability is increased more markedly following splenectomy than it is after other upper abdominal operations.

Abdomen↗
PubMed1975

The influence of beta-adrenergic blockade upon baseline blood coagulation and fibrinolytic activity and upon the responses to venous occlusion.

Twenty volunteers were assessed for baseline coagulation (Thrombelastography, Factor VIII and platelet count) and fibrinolytic (Euglobulin Lysis Time and Fibrin(ogen) Degradation Products) activity two hours after ingestion of 60 mgm propranolol or an identical placebo administered on a double blind basis. The responses of these parameters to a fifteen minute period of venous occlusion was also assessed. Beta adrenergic blockade reduced baseline FDP titres but did not affect other parameters, nor the local response to venous occlusion. During occlusion no significant change in coagulation activity could be detected in the non-occluded arm, but a small but statistically significant shortening of ELT was observed. Since this effect was prevented by propranolol it is probably mediated through adrenergic mechanisms. Adrenergic stimuli appear to influence episodes of coagulation and fibrinolysis during everyday activity, but do not contribute to baseline levels of coagulation or fibrinolytic function.

Adult↗
PubMed1975

The adrenergic response to cardiopulmonary bypass.

12 out of 13 patients who underwent cardiac surgery requiring extracorporeal circulation survived the operation. Arterial and venous catecholamines were measured throughout the operation. Larges rises in catecholamine levels were not seen although significant changes did occur in arteriovenous differences and also between samples at certain points in the operation. These facts do not agree with Lillehei's findings (3) and may reflect improvements in surgical technique, anaesthesia and the reduced time on bypass. However the lack of an overall measurable adrenergic response in terms of plasma catecholamine levels does agree with similar findings after open heart surgery (4) and during other surgical procedures (5).

Adolescent↗
PubMedDate not supplied

Homology between Streptomyces genes coding for synthesis of different polyketides used to clone antibiotic biosynthetic genes.

Many important antibiotics such as tetracyclines, erythromycin, adriamycin, monensin, rifamycin and avermectins are polyketides. In their biosynthesis, multifunctional synthases catalyse iterated condensation of thio-esters derived from acetate, propionate or butyrate to yield aliphatic chains of varying length and carrying different alkyl substituents. Subsequent modifications, including aromatic or macrolide ring closure or specific methylations or glycosylations, generate further chemical diversity. It has been suggested that, if different polyketide synthases had a common evolutionary origin, cloned DNA coding for one synthase might be used as a hybridization probe for the isolation of others. We show here that this is indeed possible. Study of a range of such synthase genes and their products should help to elucidate what determines the choice and order of condensation of different residues in polyketide assembly, and might yield, by in vitro recombination or mutagenesis, synthase genes capable of producing novel antibiotics. Moreover, because genes for entire antibiotic pathways are usually clustered in Streptomyces, cloned polyketide synthase genes are valuable in giving access to groups of linked biosynthetic genes.

Anthraquinones↗
PubMedDate not supplied

A dose-escalation study of large doses of naloxone for treatment of patients with acute cerebral ischemia.

A dose-escalation study was performed in 27 patients to determine the highest safe and potentially optimal dose of naloxone for treatment of acute cerebral ischemia. All patients received a bolus of naloxone followed by a continuous 24 hour infusion at an hourly rate 50% of the bolus. Loading doses ranged from 2.5 to 200 mg/m2. Total patient doses ranged from 52.3 to 4978 mg. No major dose-related side effects occurred. This study was not designed to determine naloxone's efficacy in stroke, but transient or sustained improvement was observed in 13 patients. Three patients' neurological condition worsened within three hours after the naloxone was discontinued. Our experience suggests that further therapeutic trials of naloxone are worthwhile.

Acute Disease↗
PubMedDate not supplied

Echocardiographic evaluation of young adults with nonhemorrhagic cerebral infarction.

We reviewed echocardiographic findings in patients aged 15 to 45 years with acute nonhemorrhagic cerebral infarction (NHCI). Among 132 patients with NHCI, 96 (72.7%) had M-mode and two-dimensional echocardiography, including contrast echocardiography with intravenous saline injection when clinically indicated. Echocardiograms were abnormal in 33 patients. Of these, 7 had other conditions that could cause NHCI. Echocardiography corroborated the clinical diagnosis of a cardiogenic source for cerebral infarction in 17 others. The other 9 had no other clues for cardiovascular disease. Potential etiologies of NHCI diagnosed by echocardiography in these 9 cases included: paradoxical embolism, 5 patients; right atrial myxoma, 1; rheumatic mitral valve vegetation, 1; myxomatous mitral valve (marantic endocarditis at postmortem), 1; and left atrial enlargement associated with decreased left ventricular function, 1. Routine echocardiography frequently conveys useful information in patients under age 45 with NHCI. In young patients with cerebral embolism of unknown etiology if routine M-mode and two dimensional echocardiographic studies are normal, contrast echocardiographic studies should be performed to rule out intracardiac shunts and the possibility of paradoxical cerebral embolism.

Adolescent↗