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Biomedical subjects

C Hart

Publications and source records attributed to C Hart.

At least 73 records · Page 4Linked to original sources
PubMed1988

Insulin-related materials in the nervous system of vertebrates and non-vertebrates: possible extrapancreatic production.

Studies from multiple laboratories with a range of methods raised the possibility that insulin production occurs naturally at extrapancreatic sites. Part A covers the presence of insulin-related materials in organisms that do not have an endocrine pancreas, including unicellular prokaryotes and eukaryotes as well as multicellular non-vertebrate animals (insects et al.) and plants. Part B covers possible production of insulin by extrapancreatic tissues of vertebrates that are remote from a source of pancreatic insulin e.g. early chick embryos and mammalian cells in culture. Part C covers possible extrapancreatic insulin production in mammals in vivo. Each section ends with an outline summary with evidence in favor of and against the hypothesis.

Amino Acid Sequence↗
PubMed1987

Frog brain and liver show evolutionary conservation of tissue-specific differences among insulin receptors.

The insulin receptors of frog brain and liver show features typical of other insulin receptors with regard to affinity and specificity of binding to insulins and proinsulin, solubility in Triton X-100, binding to and elution from wheat germ agglutinin, and insulin-sensitive tyrosine kinase activity. Likewise, the brain and liver receptors differ from one another in electrophoretic mobility and susceptibility to treatment with neuraminidase, analogous to brain and liver receptors of reptiles, birds, and mammals; while the functional implications of these differences are unknown, their evolutionary conservation for 400-500 million years suggests the possibility that they might have importance.

Animals↗
PubMed1986

Failure to sense P waves during DDD pacing.

ECG tracings of three patients in whom AV universal (DDD) pacemakers were implanted intermittently demonstrated dropped P waves. In one patient, true atrial undersensing was present; in the others, sensing of the atrial electrode was appropriate, but sensing of sinus P waves was intermittently blocked by normal pacemaker operation. In this report we discuss the electrocardiographic diagnosis of atrial undersensing in order to avoid unnecessary reinterventions.

Aged↗
PubMed1986

Development of brain insulin receptors: structural and functional studies of insulin receptors from whole brain and primary cell cultures.

We studied the structural and functional characteristics of insulin receptors from rat brain and liver from late gestation through adulthood as well as from cultured neuronal and glial cells from neonatal rats. Specific insulin binding was present on membrane preparations from brain and liver at all stages of development studied, with maximal binding in neonates greater than 19-day-old fetuses greater than adults for both brain and liver. Maximal specific binding to cultured neuronal and glial cell membranes was similar (6.2% vs. 7.1%, respectively). [125I]Iodoinsulin cross-linking to the insulin receptor demonstrated that the mol wt (Mr) of the brain alpha-subunit was less than that of the liver alpha-subunit at all stages. [125I]Iodoinsulin cross-linking also demonstrated that the glial cell alpha-subunit (Mr, 130,000) migrated on sodium dodecyl sulfate-polyacrylamide gel electrophoresis to a position intermediate between the liver (Mr, 135,000) and brain (Mr, 119,000), whereas the neuronal cell alpha-subunit (Mr, 118,000) comigrated with the brain alpha-subunit. In solubilized lectin-purified preparations from brain and liver during development as well as from neuronal and glial cells, insulin stimulated phosphorylation of the beta-subunit. The Mr of the brain beta-subunit, as determined by migration on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, was less than that of the liver beta-subunit. The neuronal cell beta-subunit comigrated with the brain beta-subunit while the glial cell beta-subunit migrated to a position intermediate between the brain and liver beta-subunit. Solubilized lectin-purified preparations from all tissues demonstrated insulin-stimulable phosphorylation of exogenous substrates. From these studies we conclude that 1) functional insulin receptors are present in the brain during development in the rat; and 2) the structural differences demonstrated between neuronal and glial cell and between brain and nonneuronal insulin receptors taken together with previously demonstrated functional differences of the insulin receptor on these tissues suggest a unique function for insulin receptors on neuronal tissues.

Age Factors↗
PubMed1981

Nurses in action.

Explore the source record for details and available documents.

Legislation, Nursing↗
PubMed1981

Staging Meniere's disease and reporting results in Meniere's disease: symposium panel discussion.

At its recent spring meeting, the American Neurotologic Society devoted a portion of its program to a symposium on staging Meniere's disease and reporting results. One of the problems discussed, was which preoperative audiogram should be used for reporting results of any treatment. I think that it is very important that we, as otologists, try to look at Meniere's disease or any inner ear dysfunction in a more scientific way. Some of you may feel, on initial evaluation of this material, that it is too cumbersome to be practical in your daily clinical work. However, we feel we have put forth a reasonable staging system and method of reporting results that can be quite helpful once the simple routine of using them has become established. The vertigogram, for example, which is designed to be very simple and not require any sophisticated equipment, should be as easy to read as an audiogram. If we try to approach the vagaries of Meniere's disease or any inner ear dysfunction in a more scientific fashion, I am sure that in several years we will be in a much better position collectively to evaluate our results and to help our patients. This type of comprehensive staging system for all of the components in Meniere's disease or any inner ear dysfunction will enable us to objectify diagnoses and treatment results so that they can be easily compared. We have put forth some of the ideas and methods that we think will help us arrive at a consensus for reporting results. We encourage you to try some of the suggestions presented in this article and welcome your comments and ideas for improving this staging system and method for reporting results.

Audiometry↗