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Biomedical subjects

S McMahon

Publications and source records attributed to S McMahon.

65 records · Page 4Linked to original sources
PubMed1979

The interrelationship of superoxide dismutase and peroxidatic enzymes in the red cell.

Activities of superoxide dismutase (superoxide:superoxide oxidoreductase, EC 1.15.1.1) and catalase (hydrogen-peroxide:hydrogen-peroxide oxidoreductase, EC 1.11.1.6) were determined during the course of incubation of red cell suspensions with 1,4-naphthoquinone-2-sulfonic acid. In the absence of glucose, incubation with napthoquinone sulfonate resulted in an inhibition of catalase and superoxide dismutase. The catalase inhibitor, 3-amino-1,2,4-triazole enhanced inactivation of catalase in the presence of naphthoquinone sulfonate and this in turn led to augmented inhibition of superoxide dismutase. The presence of glucose in the incubation medium prevented napthoquinone sulfonate-induced enzyme inhibition in the absence of aminotriazole, but had little effect in the presence of aminotriazole. The relevance of these findings to the cellular interrelationship of peroxidatic enzymes and superoxide dismutase is discussed.

Amitrole↗
PubMed1976

Potentiation of T-cell mediated immunity by levamisole.

Cell-mediated immunity is a requirement for recognition and elimination of cells and for prevention or treatment of a variety of diseases. Therefore, the development of a product potentially active in increasing immunity involves its testing in assays specific for cell-mediated immunity. The effectiveness of a single administration of levamisole was demonstrated in the rejection of isografts in a male to female C57BL/6 system, and on the enhancement of levels of the delayed type hypersensitivity (DTH) to sheep red cells (SRBC). Indeed, in five on nine tests, an injection of 25 mg/kg of levamisole to female recipients either on the day of grafting or 7 days after grafting resulted in a RT50% rejection time of 25 days, compared with 46 days in untreated controls. Levamisole administered at the time of immunization with various doses of SRBC elicited earlier, higher and more sustained DTH levels than in untreated controls. Such induction of T-cell activation was accompanied by a switch on anti-SRBC antibodies from IgM to IgG. These findings confirm and extend data evidencing the ability of levamisole to recruit and activate T cells for an increased or restored cell-mediated immunity.

Animals↗
PubMed1975

The effect of metal ions on the atypical mycobacteria: growth and colony coloration.

The effect of 30 metal ions on growth and colony color has been evaluated for 215 isolates of "atypical" mycobacteria and 5 isolates of Mycobacterium tuberculosis. Of the total number of ions tested, ten proved to have a variable effect on growth and eight induced specific changes in colony coloration. Although both effects could be generally related to the Runyon grouping system, neither procedure proved to be practical or specific for differential identification of individual species. Spectrophotometric analyses of acetone extracts were made from representative strains of "atypical" mycobacteria, grown in the presence (test) or absence (control) of metal ions, in an attempt to determine the chemical nature of metal ion induced color changes in colonies of these organisms. Induced colors were not extractable with organic solvents, indicating that these colors are not lipid associated. In all cases where applicable (chromogenic strains) the naturally occurring carotenoid pigments were found to be unaffected, in their spectral properties, by the presence of metal ions even though the natural yellow color was frequently masked by the ion induced colors. The close association of metal ion induced colors with acetone nonextractable cell components suggests the presence of reduced metal ions or the formation of metal hydroxides. The apparent presence of several metal ion reductase systems and their physiological implications are discussed.

Metals↗
PubMedDate not supplied

Ablation of atrial insertion sites of left-sided accessory pathways in children: efficacy and safety of transseptal versus transaortic approach.

Left-sided accessory pathways are a common substrate for supraventricular tachycardias in children. A transseptal approach to catheter ablation has been primarily advocated in this population because of concerns regarding vascular injury, aortic, and mitral valvular damage using the transaortic approach via retrograde femoral arterial cannulation. However, the transaortic approach is simpler and may be less time consuming. We, therefore, compared the efficacy and safety of the transseptal vs the transaortic approach in 49 consecutive pediatric patients. In both groups, the atrial insertion site of the accessory pathways was targeted. Postprocedure two-dimensional and Doppler echocardiograms were obtained in all patients. The transseptal and transaortic groups were similar in age (15.8 +/- 1.6 vs 13.5 +/- 3.6 p NS), manifest vs concealed (9/5 vs 20/15), and number of radiofrequency lesions (4 vs 6). Fluoroscopy time was significantly shorter in the transaortic group (33 vs 58 min, p < 0.05). The only evident complications were mild mitral regurgitation seen in two patients (one in each group). Two patients in the transseptal group had recurrence of tachycardia on follow-up and were successfully ablated by the transaortic method. In this series from a single center, a transaortic approach to ablation of left-sided accessory pathways in children older than 4 years was as effective as a transseptal approach.

Adolescent↗
PubMedDate not supplied

Nursing students respond to a computer assignment.

Computer-generated information is becoming increasingly important in nursing. Nursing schools are faced with the need to ensure that students have basic informatics skills and rudimentary computer literacy. This article describes the introduction of an assignment using electronic communication skills within a teaching-learning course in a baccalaureate program. The assignment was designed to introduce the students to several tasks that would be useful to them in their studies as well as in their care of clients. Students learned to send electronic mail, post to a class list, use search engines, access libraries, and critique web pages. They developed increased confidence and skill, advancing from informed user to proficient user status as identified by Ronald & Skiba. The students' appraisal of the assignment in terms of value to their nursing education and their nursing careers indicated that they recognized the value of these skills for their professional nursing lives. Activities were monitored for content and technical glitches. Lessons learned are highlighted, and "Inbox overload" is identified. The authors found that nursing curricula can be designed to meet the challenge of fostering computer literacy. The assignment could be easily adapted for continuing education or other professional education endeavors.

Attitude to Computers↗