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Biomedical subjects

M Thomas

Publications and source records attributed to M Thomas.

At least 631 records · Page 35Linked to original sources
PubMed1991

Continuing medical education as a strategy for improving general practice--experiences from Vellore.

One of the neglected areas in medical education is undoubtedly organized continuing medical education (CME) for the general practitioners. A programme on CME for general practitioners working under difficult and varied conditions is reported. The aim of the programme was to improve knowledge, skills and attitude of the practitioners, and its measurable effects are improvement of knowledge and skills. Attitude changes and final effect on patient care are difficult to evaluate and methods need be developed for this.

Education, Medical, Continuing↗
PubMed1991

The pharmacodynamics and pharmacokinetics of a novel thromboxane receptor blocking drug vapiprost (GR32191) after single intravenous doses in healthy subjects.

1 The effect of single, serially increasing, intravenous doses of a specific thromboxane receptor blocking drug, vapiprost, upon platelet aggregation induced ex vivo by the thromboxane A2 mimetic, U-46619, was examined in 12 healthy males. 2 Subjects received either 1 (n = 1 subject), 2 (n = 6), 3 (n = 2), or 4 (n = 3) administrations of vapiprost within the dose range 0.125 to 16 mg and, in random order, placebo on separate study days at intervals of at least 48 h. 3 All doses of vapiprost produced an immediate antagonism of U-46619-induced platelet aggregation in whole blood. Both the magnitude and duration of the rightward displacement of the concentration-effect curves increased with dose. Although lower doses produced parallel displacements of these curves, with the higher doses the maximum response to U-46619 was reduced such that 50% platelet aggregation was not achieved. After the 16 mg dose of vapiprost, virtually complete suppression of platelet aggregation (up to a concentration of 30 microM) was seen. This degree of inhibition was maintained for 2 h after dosing, following which there was a gradual return to pre-dose U-46619 sensitivity over the next 12 to 24 h. U-46619-induced platelet aggregation was unaffected by placebo. 4 Across the dose range, vapiprost was rapidly cleared from plasma, with an elimination half-life of 69-84 min and a plasma clearance of 514-721 ml min-1.(ABSTRACT TRUNCATED AT 250 WORDS)

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1991

Effect of hepatic cryotherapy on serum CEA concentration in patients with multiple inoperable hepatic metastases from colorectal cancer.

Eleven patients with multiple hepatic metastases from colorectal cancer, all judged inoperable, were treated by cryotherapy using a probe through which liquid nitrogen was circulated using a single freeze thaw sequence. Localization of metastases, positioning of the probe and monitoring of ice ball size was by intra-operative ultrasound. Serum carcinoembryonic antigen (CEA) was measured in these patients: there was a postoperative fall in all but two. In all but one, there has been a subsequent rise. Speed and degree of rise of CEA varied between patients. Serial CEA may be an effective means of monitoring the effect of hepatic cryotherapy.

Carcinoembryonic Antigen↗
PubMed1991

Flunarizine in migraine prophylaxis: an Indian trial.

Flunarizine, a calcium channel blocker is considered useful in migraine prophylaxis. We report the first Indian trial with this drug. Fifteen patients with migraine were studied in a 6 months double-blind, placebo-controlled crossover trial. Flunarizine was superior to placebo in reducing the severity and duration of the individual attacks though there was no statistically significant effect on frequency of migraine attacks. The side effects most frequently caused by flunarizine were weight gain and daytime sleepiness.

Adult↗
PubMed1991

Effects of Bordetella pertussis infection on human respiratory epithelium in vivo and in vitro.

Bordetella pertussis infection probably involves attachment to and destruction of ciliated epithelial cells, but most previous studies have used animal tissue. During an epidemic, nasal epithelial biopsy specimens of 15 children (aged 1 month to 3 1/2 years) with whooping cough were examined for ciliary beat frequency, percent ciliation of the epithelium, and ciliary and epithelial cell ultrastructure. In addition, the in vitro effects of filtrates from a 24-h broth culture and of tracheal cytotoxin derived from B. pertussis on human nasal tissue organ culture were measured. B. pertussis was cultured from nasal swabs from 12 children. The mean ciliary beat frequency of their nasal biopsy specimens, 11.3 Hz (range, 10.4 to 13.0 Hz) was similar to that found in biopsy specimens from 10 normal children (mean, 12.5 Hz; range, 11.8 to 13.5 Hz). The abnormalities of the epithelium observed in 14 of 15 patients were a reduction in the number of ciliated cells, an increase in the number of cells with sparse ciliation, an increase in the number of dead cells, and extrusion of cells from the epithelial surface. In vitro, neither culture filtrate nor tracheal cytotoxin had any acute effect on ciliary function, but culture filtrate and tracheal cytotoxin (1 and 5 microM, respectively) caused extrusion of cells from the epithelial surface of turbinate tissue, loss of ciliated cells, an increased frequency of sparsely ciliated cells, and toxic changes in some cells. These changes were dose dependent and progressive, and between 36 and 90 h ciliary beating ceased. The observations made with patient tissue confirm that B. pertussis infection damages ciliated epithelium, and the in vitro experiments suggest that tracheal cytotoxin may be responsible for the abnormalities observed in vivo.

Bacterial Adhesion↗
PubMed1991

A comparative study of diazepam and acupuncture in patients with osteoarthritis pain: a placebo controlled study.

Forty-four patients with chronic cervical osteoarthritis took part in this study. Patients were treated with acupuncture, sham-acupuncture, diazepam or placebo-diazepam in randomized order. Pain was rated on visual analogue scales before, during, and after treatment. Two scales were separately used to rate the intensity (sensory component) and the unpleasantness (affective component) of pain. The results analyzed from these trials show that diazepam, placebo-diazepam, acupuncture and sham-acupuncture have a more pronounced effect on the affective than on the sensory component of pain. Acupuncture was significantly more effective than placebo-diazepam (p less than 0.05), but not significantly more effective than diazepam or sham-acupuncture.

Acupuncture Analgesia↗
PubMed1991

The clinical pharmacology, pharmacokinetics and metabolism of sumatriptan.

Clinical pharmacology studies were undertaken in young healthy volunteers, in a small number of elderly subjects and in migraine subjects during and between attacks. Absorption after subcutaneous and oral administration was rapid. Bioavailability was nearly 100% after subcutaneous administration and averaged 14% after oral administration. Elimination was predominantly by metabolism to a non-active indoleacetic acid analogue. The plasma half-lives of sumatriptan and the metabolite were about 2 h. Pharmacokinetic and pharmacodynamic variables were similar in all groups studied and were not altered by the presence of food, alcohol, dihydroergotamine or prophylactic migraine treatments. Sumatriptan produced a number of minor adverse events, but had no clinically significant effect on routine haematological or biochemical investigations using the intravenous, subcutaneous or oral routes. Transient rises in blood pressure were observed which were no greater than those that would be anticipated during moderate exercise. The physician-administered subcutaneous injection resulted in transient stinging at the site of injection in many subjects; administration using the auto-injector was better tolerated.

Aged↗
PubMed1991

Lung vascular injury after administration of viable hemolysin-forming Escherichia coli in isolated rabbit lungs.

Escherichia coli hemolysin, a transmembrane pore-forming exotoxin, is considered an important virulence factor. In the present study, the possible significance of hemolysin production was investigated in a model of septic lung failure through infusion of viable bacteria in isolated rabbit lungs; 10(4) to 10(7) E. coli/ml perfusate caused a dose- and time-dependent appearance of hemolysin, accompanied by release of potassium, thromboxane A2, and PGI2 into the perfusate. Concomitantly, marked pulmonary hypertension developed. Inhibitor studies suggested that the pressor response was predominantly mediated by pulmonary thromboxane generation. Administration of hemolysin-forming E. coli additionally caused a protracted, dose-dependent increase in the lung capillary filtration coefficient, followed by severe edema formation. The permeability increase was independent of lung prostanoid generation. An E. coli strain that releases an inactive form of hemolysin completely failed to provoke the described biophysical and biochemical responses. Preapplication of 2 x 10(8) human granulocytes was without effect in the present experimental model. We conclude that the hemolysin produced by low numbers of E. coli organisms can provoke thromboxane-mediated pulmonary hypertension and severe vascular leakage. E. coli hemolysin and, possibly, other related cytolysins may thus contribute directly to the pathogenesis of acute respiratory failure under conditions of sepsis or pneumonia.

6-Ketoprostaglandin F1 alpha↗
PubMed1991

The effect of organophosphorus compounds on serum pseudocholinesterase levels in a group of industrial workers.

This paper presents the findings of a study of serum pseudocholinesterase activity in a group of 36 industrial workers chronically exposed to organophosphorus (OP) compounds. The mean pseudocholinesterase level of the workers was significantly lower than that of 36 other workers without a history of similar exposure. Although there was a high incidence of clinical features suggestive of OP compound toxicity in the exposed workers, no significant correlation between serum pseudocholinesterase levels and clinical symptoms and signs was found. Six exposed workers, found to have low serum pseudocholinesterase levels, were transferred for 6 months to work areas which did not involve OP exposure, whereupon their levels rose significantly back to the normal range.

Adult↗
PubMed1991

Thyrotropin receptor antibodies following treatment with recombinant alpha-interferon in patients with hepatitis.

We measured thyrotropin receptor antibodies in serum obtained from 2 groups of patients participating in clinical trials of recombinant interferon-alpha 2b for viral hepatitis. Group I: Patients with hepatitis B (N = 8), received interferon 5 x 10(6) units thrice weekly for 4 months. Group II: Patients with non-A, non-B hepatitis (N = 16) were randomized to receive interferon in a dose of either 0.25 x 10(6) or 3 x 10(6) U thrice weekly for 6 months and then crossed over to receive the other dosage schedule for a further 6 months. None of the patients developed thyrotoxicosis. Thyrotropin receptor antibody activity was detectable within the "normal range" (less than 10 U/l) in 6 patients prior to treatment. In Group I, thyrotropin receptor antibodies became detectable in 6 patients on treatment, in 4 of whom it was 10 U/l. In Group II, thyrotropin receptor antibody activity was unchanged on low-dose interferon, but on the higher dose became detectable in 9 patients, in 7 of whom it was greater than 10 U/l. We conclude that treatment with interferon is associated with the development of thyrotropin receptor antibodies in a large proportion of patients. It is possible that in some patients treated with higher doses of interferon the increase in thyrotropin receptor antibody activity may be sufficient to induce hyperthyroidism.

Adult↗
PubMed1991

Correlation between culture of Mycobacterium tuberculosis and antimycobacterial antibody in lumbar, ventricular and cisternal cerebrospinal fluids of patients with tuberculous meningitis.

In this study positive culture for M. tuberculosis were obtained, 20% in lumbar cerebrospinal fluid (CSF), 75% in ventricular CSF and 87.5% in cisternal CSFs of patients with tuberculous meningitis. Low culture positivity in lumbar CSF is due to the low density of circulating tubercle bacilli in lumbar CSF than in cisternal or ventricular CSFs. However antimycobacterial antibody in lumbar, cisternal and ventricular CSFs circulate in significant titres and are not statistically different from one another. Since specimens of CSF can not be obtained from cisternal or ventricular routes for the routine bacteriological investigations in patients with tuberculous meningitis, detection of antimycobacterial antibody of M. tuberculosis antigen 5 in lumbar CSF by an indirect ELISA may be considered as an aid for the diagnosis of tuberculous meningitis, particularly when repeated CSF cultures are negative for M. tuberculosis.

Antibodies, Bacterial↗
PubMed1991

Ultrasound and HIDA: scanning in evaluating bile leaks after cholecystectomy.

Ultrasound and 99Tcm-HIDA scanning were compared in the evaluation of postoperative biliary leakage after cholecystectomy. In thirty-five patients the abdomen was scanned and imaged on the first postoperative day. Isotope activity in the right upper quadrant and whole abdomen was determined to obtain an activity ratio. Ultrasonography was also performed. Accumulation of 99Tcm-HIDA in the gall bladder bed or over the surface of the liver was regarded as evidence of a bile leak. Eleven patients had abnormal 99Tcm-HIDA images (activity ratios of 0.20-0.77, mean 0.51) but only five patients had loculated fluid on ultrasound scanning. Twenty-four patients had normal 99Tcm-HIDA images (activity ratios of 0-0.17, mean 0.21), but fifteen of these had loculated fluid on ultrasound scanning. We conclude that bile leaks occur in 30% of patients following cholecystectomy and are best detected by 99Tcm scanning rather than ultrasonography.

Adult↗
PubMed1991

Intracranial haematoma resulting from lightning stroke.

Intra-cerebral haemorrhage due to lightning stroke is extremely rare. We report a 45 year old woman who developed intracranial haemorrhage due to a direct lightning stroke. This was proved by CT scan. The haematoma was evacuated surgically, resulting in full neurological recovery of the patient.

Brain Edema↗