Biomedical subjects
Publications and source records attributed to B Davies.
Although the relation between the virus of condyloma acuminatum and carcinoma of the cervix has been suspected, in the patient whose report follows, the presence of the viral lesion in the cervix next to an area of carcinoma in situ was demonstrated histologically.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
A radioreceptor assay (RRA) recently developed in this laboratory for beta-adrenoceptor antagonists in plasma was evaluated in normal volunteers and compared with a radioimmunoassay (RIA) for propranolol. The RRA depends upon the ability of beta-adrenoceptor antagonists to complete with a radiolabelled ligand for beta-adrenoceptor binding sites on lung membranes. Unlike other assays, it measures biologically active drugs including active metabolites of the parent compound. In volunteers given a single oral dose of (+/-)-propranolol, considerable differences between the two assay methods were demonstrated. In other experiments this difference was shown to relate to the RIA's sensitivity to the inactive (+)-isomer of propranolol and possibly to inactive metabolites. The facility of the RRA in measuring plasma levels of several other non-selective beta-adrenoceptor antagonists was also demonstrated. By employing (-)-propranolol as the standard in the RRA, all of these drugs can be directly compared with a single and relatively simple assay technique.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
This study defines patients with symptomatic Hodgkin's disease for whom risks of staging laparotomy (LAP) outweigh benefits conferred by accurate knowledge of stage. From a database of more than 900 pathologically-staged patients, probabilities of pathological stage are calculated for combinations of basic findings and lymphangiogram results. Decision-making thresholds are defined at which results of treatment after LAP, taking operative mortality into account, are equivalent to immediate treatment appropriate to clinical stage. These thresholds are substantially altered by varying LAP mortality estimates, by assigning a false negative rate to LAP, and by considering uncertainty in treatment results. Fifty-four combinations of findings are described for which immediate therapy with MOPP is justified; total nodal irradiation (TNI) is never indicated in B patients without prior LAP staging. Analysing 94 B patients who had LAP showed an appreciable number might have been spared this, particularly when uncertainty in treatment results is considered. With 0.03 (=3%) uncertainty in treatment, and 1% LAP mortality, LAP was not indicated in one in seven patients; nearly one third of patients should have immediate treatment with 3% LAP mortality. Threshold analysis can define those patients for whom risks of LAP outweigh benefits.
A cardiovascular study of a new antidepressant, mianserin, given at 60 mg a day for a three-week period to 10 ambulant, moderately depressed patients is described. No effects on cardiac conduction were found by means of His bundle electrocardiography. Nine of 10 depressed patients improved while on the medication; mild sedation was the only side effect noted.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Serum and sputum concentrations of ampicillin or amoxycillin were measured in patients admitted to hospital for acute exacerbations of chronic bronchitis with purulent sputum. Mean peak serum levels of nearly 12 mg/l were found after 1600 mg bacampicillin (mean peak level in sputum 0.85 mg/l). The serum and sputum concentrations after 750 mg amoxycillin and 800 mg bacampicillin were comparable (mean peak serum levels approximately 9.5 mg/l, sputum concentrations 0.4 to 0.5 mg/l) although the drugs were not given in equimolar doses. Results after 1000 mg ampicillin by mouth were less satisfactory (mean peak serum level 7.8 mg/l) and only 0.25 mg/l was attained in the sputum. Minimum inhibitory concentrations of ampicillin and amoxycillin were measured for 177 Haemophilus influenzae strains. Most of the ampicillin MIC values were between 0.125 and 0.5 mg/l but more of the strains required 0.5 mg/l of amoxycillin. The amoxycillin MIC values were often one or two dilutions higher than those of ampicillin (p less than 0.001).
The results of antibiotic therapy in 271 patients suffering from acute exacerbations of chronic bronchitis are presented. The effectiveness of the better absorbed ampicillin esters (pivampicillin and bacampicillin) is confirmed, but side-effects from the pivampicillin present problems whereas bacampicillin is excellently tolerated, even in twice daily doses of 1600 mg. Amoxycillin, if given in 750 mg doses three times daily by mouth, is also safe and effective against Haemophilus influenzae. However, if accurate MIC results are not available for both ampicillin and amoxycillin, the lesser degree of sensitivity to amoxycillin suggests that use of an ampicillin ester (such as bacampicillin) is to be preferred. Prophylactic use of antibiotics in chronic bronchitis patients does not seem logical to us.
Explore the source record for details and available documents.
In 10 patients with chronic autonomic failure the clinical features and cardiovascular reflexes were correlated with the pressor responses to intravenous noradrenaline and tyramine. In all patients there was an exaggerated response to noradrenaline but a normal or only mildly exaggerated response to tyramine. Patients with lack of sinus arrhythmia and by implication baroreceptor reflex loss had greater responsiveness to pressor drugs than patients with preservation of this reflex. The responses to tyramine infusions imply that there must be sufficient noradrenaline released at defective sympathetic endings for a pressor response to occur. However, the lack of rise of plasma noradrenaline following tyramine, except in the patients with pure autonomic failure, clearly separates these responses from those of normal subjects. These results can be explained by the presence of lesions of both central and peripheral sympathetic pathways in patients with chronic autonomic failure and multiple system atrophy or Parkinsonism. The peripheral lesion, which is incomplete, may consist of replication of the receptors so causing supersensitivity with a duration of response that is little prolonged. The peripheral defect in the two patients with pure autonomic failure was found to be more complex and the prolonged response in one of these patients suggests the possibility of defective re-uptake or metabolism of noradrenaline. Clearly further study of the defects of sympathetic endings is required, including the use of other techniques such as catecholamine fluorescence. The extreme supersensitive responses underline the need for blood pressure monitoring during pressor drug studies prior to treatment, if the hazards of recumbent hypertension are to be avoided.
1 Treatment of postural hypotension due to chronic autonomic failure with fludrocortisone increased the pressor sensitivity to intravenous noradrenaline. Fludrocortisone increased the blood pressure in the standing but not the lying position. These effects of fludrocortisone may be the result of increased sensitivity of vascular receptors to noradrenaline. 2 The pressor action of angiotensin II, to which patients were supersensitive, may have involved the stimulation of alpha-adrenoceptors since it was partially antagonised by phentolamine. 3 Saralasin had a marked, paradoxical, pressor effect. This may have been mediated by vascular alpha-adrenoceptors because log dose-response curves of saralasin-induced increases in systolic pressure were shifted to the right in a parallel fashion after phentolamine. 4 Fludrocortisone treatment increased the pressor sensitivity to intravenous saralasin but not to angiotensin-II.
Explore the source record for details and available documents.
Aspiration pneumonitis is an important cause of many anesthetic and non-surgical deaths and complication. One hundred and eight cases from 1964 to 1974 were reviewed to study the factors associated with aspiration pneumonia. Forty surgical and 68 non-surgical patients were evaluated and compared. Predisposing factors included impaired consciousness, esophageal and neurological disorders, cardiac resuscitation, debilitation, presence of a nasogastric tube or tracheostomy. The most common findings in both groups were dyspnea, cough, cyanosis, fever, tachycardia, rhonchi, rales and wheezes. Sputa of 64 patients failed to reveal the precise etiologic agent. High mortality (30%) and morbidity were found in both groups even with optimum treatment. The causes of morbidity in both groups of patients were pneumonia, lung abscess, myocardial infarction, gastrointestinal hemorrhage, and pulmonary embolus. Prevention, with particular attention to high-risk patients and to factors influencing aspiration in groups of surgical and non-surgical patients, is the solution to the problem.
Explore the source record for details and available documents.