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Biomedical subjects

H C Taylor

Publications and source records attributed to H C Taylor.

At least 55 records · Page 3Linked to original sources
PubMed1981

An international system for the education of students of medicine and other health professionals in human reproduction. The FIGO teaching manual: a status report.

An analysis of the effectiveness of FIGO's Teaching Manual on Human Reproduction is reported on the basis of answers to a questionnaire received from 100 heads of teaching departments, chiefly of obstetrics and gynecology. These represented 32 countries widely distributed throughout the developing countries of the world. The most significant finding was the evidence of the very large number of medical and other students that could be reached through the principle of placing superlatively good teaching material in the hands of key educators in their native country. Additional answers to the questionnaire provided information on the way courses were organized about the material and suggestions as the useful changes, possible expansion of subject matter, and the felt need for an updated edition.

Education, Medical, Undergraduate↗
PubMed1980

Physarum myosin light chain binds calcium.

Myosin from the slime mold Physarum polycephalum contains three sizes of polypeptides: a heavy chain and two light chains, LC-1 and LC-2. Using a simple qualitative test for calcium binding by comparing electrophoretic migration of the polypeptides in sodium dodecyl sulfate (SDS) acrylamide gels in the presence and absence of calcium, we have found that Physarum myosin light chain LC-2 migrates with an apparent molecular weight of 16,900 daltons in the presence of the metal ion chelator ethylene glycol bis (B-aminoethyl ether) N,N'-tetraacetic acid (EGTA). However, if calcium chloride is added to the sample prior to electrophoresis, the apparent molecular weight decreases to 16,100. Lanthanide and cadmium ions, but not magnesium, can substitute for calcium. Because the ionic radii of Ca2+, La3+, and Cd2+ are almost identical, we conclude that Physarum myosin LC-2 possesses a very size-specific binding site for calcium. Physarum myosin LC-1 and the heavy chain give no evidence for binding calcium by this test. Since cytoplasmic streaming in the plasmodium of Physarum requires calcium, our evidence indicates that the calcium-binding property of Physarum myosin LC-2 may be important in regulating the production of force by actomyosin in the ectoplasm. Unexpectedly, the myosin light chain in Physarum capable of binding calcium, LC-2, is the essential light chain, while LC-1 is a member of the regulatory class of myosin light chains [V. T. Nachmias, personal communication]. Until now, essential myosin light chains have not been shown to have high affinity divalent cation binding sites. This means a new version of the myosin-based model for actomyosin regulation by calcium may be required to explain cytoplasmic movement in Physarum, and perhaps in other motile systems involving cytoplasmic myosins as well.

Actomyosin↗
PubMed1980

Remission of pituitary-dependent Cushing's disease after removal of nonneoplastyic pituitary gland.

Transsphenoidal hypophysectomy was performed on a 28-year-old woman with pituitary-dependent Cushing's disease. Both clinical and chemical resolution of the hypercortisolism was achieved in spite of no evident pituitary microadenoma or cell hyperplasia. Histologic examination revealed widespread Crooke's changes and normal relative numbers, size, and distribution of corticotrophs. We propose that rare patients with pituitary-dependent Cushing's disease may have excessive pituitary production of adrenocorticotropic hormone in the absence of an adenoma or corticotroph cell hyperplasia.

Adrenocorticotropic Hormone↗
PubMed1976

Analysis of ribonuclease-nucleotide interactions by quantitative affinity chromatography.

Quantitative affinity chromatography on uridine-5'-(Sepharose-4-aminophenylphosphoryl)-2'(3')-phosphate was developed for the study of binding of ribonuclease species to nucleotide ligands. Elution of the native species ribonuclease-A and -S on the afffinity matrix in 0.4 M ammonium acetate, pH 5.2, containing various amounts of the soluble competing ligand 2'-cytidine monophosphate, reveals an inverse response of elution volume to concentration of soluble ligand. This response conforms to behavior expected for the competing binding equilibria enzyme-soluble ligand and enzyme-insoluble ligand. A-NALYSIS OF ELUTION DATA ALLOWS CALCULATION OF KI and KIM, the dissociation constants, respectively, for the soluble and insoluble protein-ligand complexes. The values of these chromatographically derived constants are similar to values of dissocation constants determined in solution by kinetics of inhibition by 2'-cytidine monophosphate and uridine-5'-(j-aminophenylphosphoryl)-2'(3')-phosphate. Successful competitive elution experiments with [p-F-Phe8]semisynthetic ribonuclease-S' and individual elution trials for [4-F-His12]semisynthetic ribonuclease-S' indicate the utility of the quantitative affinity chromatographic technique for determination of ligand binding properties of ribonuclease derivatives, including inactive species. Nonbiospecific aspects of the interaction of ribonuclease with the affinity matrix in ammonium acetate buffers of concentrations 0.1 M and below were noted, delinating limits of conditions allowing the biospecificity needed for ligand-binding analyses by competitive elution. The dependence of ribonuclease competitive elution behavior on the amount of protein eluted also was examined and related to theoretical considerations in the quantitative application of affinity chromatography.

Binding Sites↗