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Biomedical subjects

R M Williams

Publications and source records attributed to R M Williams.

At least 235 records · Page 13Linked to original sources
PubMed1969

Antibodies to acetylcholinesterase.

A rabbit antiserum against commercially available Electrophorus electricus acetylcholinesterase has been prepared. Five precipitation bands were distinguished by immunoelectrophoresis, but only three of these contained demonstrable enzyme activity. In an in vitro system, activity of the commercial enzyme or of highly purified acetylcholinesterase was inhibited by 70-82 per cent after incubation with antiserum. Antibody specificity was demonstrated by the absence of serological cross reactions or enzyme inhibition with bovine erythrocyte acetylcholinesterase or horse serum cholinesterase.

Animals↗
PubMedDate not supplied

Health policy and quality: an ethical dilemma.

Emergency medicine is on the front line of many important health issues, such as access for the poor and uninsured, the AIDS epidemic, and domestic violence. Virtually all key policy issues relating to emergency medicine deal with the concept of quality. During the 1970s, quality issues dealt with issues of value. Interest in quality is now vested in the tradeoff between cost containment activities and preserving access to health care. Key definitions of efficacy, effectiveness, and efficiency are provided. A policy approach to quality definition and assessment is suggested based upon the concepts of continuous quality improvement. The role of emergency physicians in health policy and the future of emergency medicine are discussed.

Emergency Medicine↗
PubMedDate not supplied

The Mars oxidant experiment (MOx) for Mars '96.

The MOx instrument was developed to characterize the reactive nature of the martian soil. The objectives of MOx were: (1) to measure the rate of degradation of organics in the martian environment; (2) to determine if the reactions seen by the Viking biology experiments were caused by a soil oxidant and measure the reactivity of the soil and atmosphere: (3) to monitor the degradation, when exposed to the martian environment, of materials of potential use in future missions; and, finally, (4) to develop technologies and approaches that can be part of future soil analysis instrumentation. The basic approach taken in the MOx instrument was to place a variety of materials composed as thin films in contact with the soil and monitor the physical and chemical changes that result. The optical reflectance of the thin films was the primary sensing-mode. Thin films of organic materials, metals, and semiconductors were prepared. Laboratory simulations demonstrated the response of thin films to active oxidants.

Electron Probe Microanalysis↗
PubMedDate not supplied

Life change stress, psychiatric symptoms, and natural killer cell activity.

Previous research has linked stress with adverse health change; however, the immunologic mechanisms mediating these changes remain poorly understood. To test whether "stress" was associated with alterations in cell-mediated immunity, we examined the correlations of self-reported life change stress (LCS) and psychiatric symptoms with natural killer cell activity (NKCA) among 114 healthy undergraduate volunteers. Although the bivariate correlation between LCS and NKCA was not significant, subjects reporting few psychologic symptoms in the face of large amounts of LCS ("good copers") had significantly higher NKCA than those experiencing high levels of both symptoms and LCS ("poor copers"). Furthermore, self-reported psychiatric symptoms were found to inversely correlate with NKCA, suggesting that symptoms such as anxiety and depression may negatively affect immunity.

Adaptation, Psychological↗
PubMedDate not supplied

Vagal afferent nerve fibres contact mast cells in rat small intestinal mucosa.

Mast cells degranulate when exposed to specific antigens (via surface bound IgE), resulting in the release of numerous pro-inflammatory mediators. Neuroregulatory substances also activate mast cells, and may effect differential mediator release, without degranulation, suggesting a role for nerves in modulating mast cell activity. We previously investigated the microanatomical relationships of intestinal mucosal mast cells (IMMC) with nerves and found extensive associations in the intestinal mucosae of rats and humans. The origins of nerves that contact IMMC have not been determined; however, recent morphological and functional studies suggest the possibility that the vagus nerve might be involved. In the current study we show that vagal afferent fibers (labeled by injecting DiI into the nodose ganglion) penetrate to the tips of jejunal villi; and that some of these nerves make intimate contact with IMMC. These data provide the microanatomical basis for direct neural communication between the central nervous system (CNS) and mast cells in the gastrointestinal mucosa.

Afferent Pathways↗