Biomedical subjects
Publications and source records attributed to D J Thomas.
A comparison has been made between the effectiveness of infusing prostaglandin E(2) with Syntocinon for the induction of labour in the presence of intact membranes. Rapid titration schedules were used to induce an early uterine response. All 15 subjects receiving prostaglandin E(2) achieved cervical dilatation, whereas this occurred in only 9 out of 15 patients receiving Syntocinon.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
A single and multiple oral dose administration study of meclofenamate sodium (Meclomen) was conducted in ten healthy male volunteers. An initial 300 mg oral dose on day 1 was followed by a 100 mg every 8 h dosage regimen on study days 4 through 18. Intensive plasma and urine sample collection was carried out over the first three study days, and for 120 h following administration of the final dose on day 18. Plasma and urine specimens were analyzed by a specific HPLC assay for unconjugated meclofenamic acid and metabolites I and II of meclofenamic acid before and after sample incubation with beta-glucuronidase. Meclofenamic acid was rapidly absorbed following oral dose administration. Concentrations of meclofenamic acid existed primarily as unconjugated drug in plasma, with only a small amount present in the conjugated form. Meclofenamic acid was rapidly eliminated, with an elimination half-life of approximately 1.3 h. This resulted in no detectable accumulation upon multiple dose administration. Metabolite I, which is one-fifth as active as meclofenamic acid in in vitro inhibition of cyclooxygenase, was present in unconjugated form at steady state in concentrations approximately 50 per cent of those of meclofenamic acid, as unconjugated drug. The majority of metabolite I in plasma existed as glucuronide conjugate. Metabolite II, which is inactive, was present in very significant concentrations in unconjugated form. Plasma protein binding determinations conducted on meclofenamic acid and metabolite I indicated that the free fraction of metabolite I was 8.7 to 10.9 times higher than that of meclofenamic acid. When the lower activity and lower steady state concentrations, but higher free fraction, are considered, it would appear that metabolite I may contribute significantly to the in vivo inhibition of cyclooxygenase activity seen after administration of meclofenamic acid.
The interactions of arsenate and arsenite with meso-2,3-dimercaptosuccinic acid (DMSA) have been characterized using carbon-13 nuclear magnetic resonance. These studies show that DMSA reduces arsenate to arsenite and complexes arsenite. Monitoring the carbon-13 signals of complexed DMSA and liberated glutathione shows that DMSA readily extracts arsenite from a (glutathione)3-arsenite complex, proving the affinity of arsenite for dithiols is greater than that for monothiols. Competition between DMSA (vicinal thiols) and dithioerythritol (1,4-dimercapto-2,3-butanediol) for binding of arsenite indicates that the binding affinity is inversely related to the distance between the two thiol groups. On the basis of these findings, a model for the interaction of arsenic with mono- and dithiol-containing molecules is proposed.
The binding of arsenite, As(III), and arsenate, As(V), by molecules in the intracellular compartment of rabbit erythrocytes has been studied by 1H- and 31P-NMR spectroscopy, uptake of 73As, and ultrafiltration experiments. For intact erythrocytes to which 0.1-0.4 mM arsenite was added, direct evidence was obtained for entry of 76% within 1/2 h and subsequent binding of As(III) by intracellular glutathione and induced changes in the hemoglobin structure (NMR), likely due to binding of As(III). These results were compared with the effect of addition of As(V) on intact erythrocytes and revealed that a smaller amount of As(V) (approximately 25%) enters the cells; the main fraction of As(V) enters the phosphate pathway, depletes ATP, and increases Pi. In contrast, As(III) did not affect the ATP level. Both 1H- and 31P-NMR data indicated striking differences between As(III) and As(V) behavior when incubated with rabbit erythrocytes. These differences were confirmed by 73As uptake and binding experiments. meso-2,3-Dimercaptosuccinic acid (DMSA), a dithiol ligand, released glutathione from its arsenite complexes in erythrocytes.
BACKGROUND AND PURPOSE: Cervical arterial dissection is a well-recognised cause for acute ischaemic stroke. Dissecting aneurysms commonly occur in the affected vessels contributing to the clinical presentation. Persistence of these aneurysms may provide a source of future embolic events as well as causing local symptoms or even be at risk of spontaneous rupture. METHODS: We describe 4 patients with traumatic internal carotid artery (ICA) dissections with aneurysm formation at the skull base. Three of the 4 patients still had carotid aneurysms on follow-up investigations and so underwent endovascular procedures using stenting and coil techniques. The carotid aneurysm resolved spontaneously in the fourth patient. RESULTS: The endovascular procedures resulted in significant reduction or obliteration of the flow within the carotid aneurysms with restoration of the true lumen diameter in the adjacent ICA in all 3 patients. No perioperative complications were experienced except for transient headache in 2 patients. CONCLUSIONS: In patients with persistent aneurysms the exact risk of subsequent ischaemic events remains unknown and prospective long-term studies are needed to ascertain this risk. If recurrent stroke rates are found to be high, then carotid stenting (with or without coil insertion) is a feasible invasive approach which could be considered in these patients.
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More than one cerebral blood flow (CBF) measurement was performed on the same occasion in three groups of patients using the intracarotid 133Xenon technique. In the anesthetized group there was a highly significant reduction in CBF (mean = 24.3%) from the first to the second measurement. In those at rest under local anesthesia there was also a significant fall (mean 9.8%). The third group, who were stimulated during the second estimation, showed no change. A second CBF determination some time after beginning a study is recommended, especially in pharmacological studies, to provide a more reliable resting control, rather than the first value which represents flow in an "activated" brain which has not yet adapted fully to its new environment.
The prospective payment system will require agencies to become more creative and network with community resources. This article describes a health needs assessment survey that provided the foundation for a parish nurse ministry. The survey revealed that parish nurses could complement home health nurses by filling some of the gaps in healthcare not provided by third-party payers.
Laparoscopic cholecystectomy has been widely performed since its introduction in 1987 by Mouret. However, conversion to open cholecystectomy is common when the surgeon encounters variant anatomy. We report 2 cases of cholecystitis and cholelithiasis in patients with left-sided gallbladders that were treated with laparoscopic cholecystectomy by the same surgeon at this institution. The patient in the first case had the condition of situs inversus totalis, and the gallbladder of the second patient was located to the left of the round ligament. In both instances, successful laparoscopic cholecystectomy was performed, and the patients recovered uneventfully.
Human papillomavirus, herpes simplex virus, and both hepatitis A and B are some of the most common sexually transmitted infections (STI) worldwide. They are preventable, but unlike bacterial STIs the person may harbor the virus in her or his body for life with periodic recurrences of active infection. Viral STIs have long-term health consequences, some of which are serious and life threatening. Nurses not only care for individuals who have a viral STI but also can provide education for prevention.
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