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Biomedical subjects

M Robinson

Publications and source records attributed to M Robinson.

551 records · Page 31Linked to original sources
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Drugs, bugs, and esophageal pH profiles.

Until relatively recently, gastroesophageal reflux disease (GERD) was thought to be a relatively trivial problem, and pharmaceutical companies initially had remarkably little interest in clinical trials for GERD. Over the last ten years, GERD therapy has become the subject of intense interest, since reflux disease is now recognized as a major market for antisecretory and prokinetic drugs. Even low-technology antacids are now known to effectively neutralize esophageal acid prevent acid reflux for up to 90 minutes. Esophageal pH profiling is known to be an excellent surrogate for clinical efficacy of GERD drugs, particularly in erosive esophagitis. Years ago, famotidine normalized esophageal mucosal exposure to pH < 4.0 only when administered in doses of 40 mg twice a day. Subsequent studies confirmed that multiple daily dosing of histamine-2 receptor antagonists (H2RAs) was mandatory for GERD treatment, with clear dose-response relationships for each agent. Proton pump inhibitors (PPIs) have each been carefully assessed in terms esophageal and gastric pH profiles. Omeprazole has a particularly flat dose response curve, making it difficult to differentiate pH or clinical effects of 20 vs. 40 mg doses. Improved rapidity of onset and/or enhanced potency is demonstrable in pH data obtained with lansoprazole, rabeprazole and pantoprazole. Such differences will translate to improved clinical efficacy, based on the meta-analyses of Richard Hunt and his group in Canada that correlate pH effects and symptom relief/healing. PPI's have dependably surpassed H2RAs and prokinetic drugs in management of the more severe grades of esophagitis. Helicobacter pylori has a peculiar relationship to GERD. There has been some concern that PPIs given to patients with H. pylori might accelerate development of severe atrophic gastritis. It is also now known that eradication of H. pylori may increase symptomatic GERD (possibly as a result of increased gastric acid secretion once the bacteria have been eliminated). New data confirm nocturnal breakthrough of acid secretion and esophageal acid exposure in three-fourths of patients on omeprazole 20 mg twice daily. This nocturnal acidity can be controlled more effectively with a nighttime dose of an H2RA than with a third dose of omeprazole. Control of acid secretion and improved gastric and esophageal pH profiles are goals of modern GERD therapy, and the product that most cost effectively normalizes esophageal acid exposure will have a substantial advantage in the ever-growing GERD marketplace.

Antacids↗
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Pregnant teens: differential pregnancy resolution and treatment implications.

Profiles on three groups of pregnant teens in a comprehensive social service agency were identified: those who followed through with a parenting plan, those who followed through with an adoption plan, and those who switched from an adoption plan to a parenting plan. Pregnant teens who switched plans were identified as high risk in terms of health histories and psychosocial profiles. Since they represent as much as one-third of the total population, service plans must be made for them that focus on these risk areas. This article addresses the identification of new subgroups in the universe of pregnant teenagers, and treatment implications.

Adolescent↗
PubMedDate not supplied

Systemic cytokine measurements: their role in monitoring the response to therapy in patients with rheumatoid arthritis.

OBJECTIVE: To determine the value of serial measurements of circulating cytokines in patients with rheumatoid arthritis in response to the introduction of disease modifying anti-rheumatic drugs (DMARDs). METHODS: A prospective 12-week study of 98 patients starting second line therapy with serial measurements of IL1 beta, IL2 receptor, IL6, TNF, and urinary neopterins as well as ESR, CRP and rheumatoid factor. RESULTS: The markers of the acute phase response fell significantly with treatment as did the rheumatoid factor. IL-6 fell in certain sub-groups (significantly so after sulphasalazine SZP) of treated patients, but no other consistent change in circulating cytokine levels was demonstrated. Urinary neopterins rose with therapy. CONCLUSIONS: The measurement of circulating cytokine levels in patients with rheumatoid arthritis is of limited benefit; macrophage function (as measured by urinary neopterins) is initially enhanced by DMARDs in patients with rheumatoid arthritis.

Adult↗
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Introducing problem-based learning into a traditional undergraduate medical curriculum.

Problem-based learning (PBL) has been introduced into the undergraduate curricula in most Canadian medical schools. In the University of Western Ontario model, we set aside 20% of time to PBL in the first two years of the programme and the rest for didactic methods. The objective of this article is to discuss 6 years of our experience with the model and the process and problems of introducing PBL into a traditional curriculum. The importance, and methods for developing good cases which are multidisciplinary and 'three-dimensional' (biological, behavioural/ psychosocial and population issues) are emphasized. The challenges have been to: integrate the underlying teaching/learning values of two different methods, develop a valid and reliable examination/evaluation procedure, and keep the faculty interested and continually improving their skills. Students have welcomed the break from lectures and the challenge to explore in-depth areas of special interest. The most positive outcomes of this curricular change have been an increased interest in medical education reform in general, and enhanced recognition of teaching in relation to appointments and promotions.

Education, Medical, Undergraduate↗
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Initial experience with an eight-month sustained-release intravitreal ganciclovir implant for the treatment of CMV retinitis associated with AIDS.

BACKGROUND AND OBJECTIVE: An intravitreal device administering ganciclovir in a sustained-release fashion has been developed for site-specific therapy of cytomegalovirus (CMV) retinitis. The initially tested devices released ganciclovir at a rate of approximately 2 micrograms/hour (Mark I device), yielding an estimated in vivo therapeutic life span of 4 months. This report describes the initial clinical results of a longer-lasting device that releases ganciclovir at a rate of 1 microgram/hour (Mark II device), designed to be effective for up to 8 months. PATIENTS AND METHODS: Over a 15-month time period, a total of 39 Mark II intravitreal ganciclovir devices were placed in 35 eyes of 29 patients with a diagnosis of CMV retinitis. At the time of implantation, none of the patients were on systemic anti-CMV therapy. RESULTS: Of the first 29 eyes of the 29 enrolled patients implanted with their initial Mark II device, 28 (97%) had no progression of retinitis at the 4-week postoperative examination. Survival analysis of these initial 29 implants revealed the median time to disease progression was 29.3 weeks (205 days). Serious ocular complications included one case of acute bacterial endophthalmitis (2.9% of eyes or 2.5% of implantations), and four cases of rhegmatogenous retinal detachment (four of 35 or 11.4% of eyes). Of the 10 patients with initially unilateral retinitis, four (40%) eventually developed contralateral disease. Five clinically suspected cases of extraocular, systemic CMV disease occurred during the study (17.2% of patients), necessitating reinstitution of systemic therapy. CONCLUSION: This small, uncontrolled pilot study indicates that the Mark II (1 mg/hour) sustained-release intravitreal ganciclovir device is effective for local control of CMV retinitis.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Further characterization of a complement-sensitive mutant of a virulent avian Escherichia coli isolate.

An attempt was made to characterize the mechanism of complement resistance operating in a virulent avian Escherichia coli isolate. Using flow cytometry to detect antibody to C3, we found that there was significantly more antibody bound to a complement-sensitive mutant of this wild type than to the parent organism, suggesting that more C3 subunits were bound to the wild type. Neither the wild type nor the mutant degraded C3. Further, the mutant was phagocytosed to a significantly greater degree than the wild type by cultured phagocytes in the presence of C5-deficient serum. These data suggest that the wild type is resistant to complement, at least in part, because of its ability to restrict C3 deposition on its surface. Therefore, the decrease in virulence seen in the mutant may be related to its increased sensitivity to complement-mediated bacteriolysis or its enhanced susceptibility to complement-opsonized phagocytosis or both.

Animals↗