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Biomedical subjects

K M West

Publications and source records attributed to K M West.

11 recordsLinked to original sources
PubMed1992

Reactive oxygen species and human spermatozoa: analysis of the cellular mechanisms involved in luminol- and lucigenin-dependent chemiluminescence.

We have shown that human spermatozoa generate and release reactive oxygen species that can be detected by chemiluminescence techniques. Analysis of the cellular mechanisms responsible for this activity suggests that the probe, luminol, undergoes an intracellular dioxygenation reaction mediated by hydrogen peroxide and a sperm peroxidase located within the acrosome. Support for this model included the following observations: (1) the luminol-dependent signal could be suppressed with peroxidase inhibitors, phenylhydrazine and sodium azide; (2) this suppression could be reversed by the addition of an azide-insensitive peroxidase, horse radish peroxidase (HRP); (3) inhibition of intracellular superoxide dismutase (SOD) with potassium cyanide (KCN) suppressed the luminol signal; (4) peroxidase activity could be detected in purified populations of human spermatozoa with 3,3',5,5' tetramethylbenzidine (TMB); (5) this peroxidase was active at the pH prevailing within the acrosomal vesicle; and (6) peroxidase activity and luminol-dependent chemiluminescence were minimal in spermatozoa exhibiting a congenital absence of acrosomes. Human spermatozoa could also generate lucigenin-dependent chemiluminescent signals that could neither be suppressed with peroxidase inhibitors nor enhanced by the addition of peroxidase. However, these signals could be enhanced by suppression of intracellular SOD with KCN or inhibited by exogenous SOD, suggesting that lucigenin was responding to superoxide anion released into the extracellular space. The ability of chemiluminescent techniques to detect and discriminate the production of superoxide and hydrogen peroxide by spermatozoa should facilitate the further analysis of reactive oxygen species as mediators of normal and abnormal human sperm function.

Acridines↗
PubMed1976

Diet and diabetes.

Explore the source record for details and available documents.

Diabetes Mellitus↗
PubMed1975

Library and information services for small hospitals.

The quality of medical care is dependent on effective and expeditious information services for physicians and other health workers. Small hospitals have been at a particular disadvantage in this respect, mainly because unit costs of library services have been quite high when delivered on a small scale with traditional resources and methods. The importance of this problem is suggested by the fact that more than half of the US hospitals have less than 100 beds, and that library services have been primitive or nonexistent in most of these institutions. Certain recent developments will permit most of these smaller hospitals to provide creditable information services at modest cost.

Costs and Cost Analysis↗
PubMed1975

Substantial differences in the diagnostic criteria used by diabetes experts.

A survey of twenty diabetologists revealed that they employ diagnostic criteria differing quite substantially. In some populations, including the general population of the United States, these disparities would result in very major differences in the rates of "diabetes." Under certain common circumstances, some diabetologists would classify as normal more than half of the one- and two-hour values considered to be abnormal by other well-qualified diabetologists.

Adult↗
PubMedDate not supplied

Standardization of definition, classification, and reporting in diabetes-related epidemiologic studies.

This working paper reviews some advantages and disadvantages of various alternative definitions and classification schemes. Certain of these alternatives were discussed by an international group of experts on the epidemiology of diabetes. It was recommended by the conferees that the following terms not be used as standard descriptors in epidemiologic reports: juvenile diabetes, juvenile-type diabetes, maturity-onset diabetes of youth (MODY), latent diabetes, subclinical diabetes, clinical diabetes, chemical diabetes, and J-type (Jamaica) diabetes. Alternative ways of describing these conditions were offered. Some, but not all, conferees favored abandonment or modification of the terms "secondary diabetes" and "pancreatic diabetes." Two alternate approaches are described in classification. One is designed to classify all types of cases in a single scheme. In this system each case is described by indices that include etiology and special etiologic concomitants, fatness, severity, type of treatment, and, if present, special or peculiar manifestations, and morbidity. This system makes it possible to classify all cases by mutually exclusive categories. A disadvantage of this scheme is that the number of combinations of classifying indices and subindices is great. Another approach is to classify cases by syndromes, using in each class a mixture of indices (e.g., etiology, severity, fatness, etc.). The conferees failed to reach a consensus in the specifics of this approach. There was considerable disagreement on how certain terms should be defined, whether they should be used, and on the degree of need for specific definitions. These designations included the terms "insulin-dependent," "idiopathic," "insulin-requiring," and "ketosis-prone." The conferees agreed that in either of the two approaches to classification, the prime indices should be those that can be ascertained by ordinary clinical methods. Much progress could be accomplished, even in the absence of international standardized definitions and classification systems, provided that authors keep in mind the need to describe the major characteristics of their cases and define the sense in which they use terms such as insulin-dependent, ketosis-prone, obese, etc.

Diabetes Mellitus↗
PubMedDate not supplied

Community screening programs for diabetes?

Considerable uncertainty and disagreement now prevail concerning the utility and priority of community screening programs for diabetes. A large majority of diabetologists believe that substantial benefits attend the early discovery of diabetes. Official statements of the American Diabetes Association support the view that mitigation of hyperglycemia lowers risk of morbidity. Much recent evidence indicates that aggressive early treatment often improves beta-cell function, thereby diminishing the severity of diabetes. Even so, some diabetologists and public health specialists question the practical benefits of community screening programs. Indeed, there is considerable evidence that, as previously performed, results sometimes have not justified costs. This article suggests that, when well designed, community screening is stil justified in some circumstances. To a considerable degree, failures of the past are correctable. The American Diabetes Association should neither approve nor disapprove community screening indisciminately. Affiliate organizations and health departments should be free to examine available evidence and local circumstances and, then, to decide whether to undertake screening programs. More care is needed in planning, executing, and critically evaluating these programs, but there is impressive and mounting evidence supporting the potential utility of the early discovery of diabetes.

Community Health Services↗