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Biomedical subjects

D McMaster

Publications and source records attributed to D McMaster.

104 records · Page 6Linked to original sources
PubMed1977

Temporary transvenous cardiac pacemaking in rural family practice.

Interested family physicians with proper training and minimal extra equipment can now employ transvenous pacemaking. Some cardiac centers have developed training programs for general internists and family physicians. We believe that this valuable procedure can, with proper physician training, be offered to patients in rural areas as well as in cardiac centers. While the number of patients in this rural family practice who require this procedure has not been great (ten patients in four years), the need is often urgent when it does occur. Use of this treatment modality with consultation in a 44-bed hospital was found to be safe and practical, although sometimes technically difficult. This paper describes the training, techniques used, results, and complications in a rural community in southeastern Nebraska. It is suggested that every hospital caring for seriously ill cardiac patients should have at least one physician trained to perform this emergency procedure.

Aged↗
PubMedDate not supplied

Isolation and amino acid sequence of urotensin I, a vasoactive and ACTH-releasing neuropeptide, from the carp (Cyprinus carpio) urophysis.

Urotensin I (UI), a 41-residue mammalian hypotensive and fish or mammalian corticotropin-releasing peptide, isolated from 0.1 N HCI extracts of urophyses of the carp (Cyprinus carpio) was purified and the amino acid sequence was determined to be: H-Asn-Asp-Asp-Pro-Pro-Ile-Ser-Ile-Asp-Leu-Thr-Phe-His-Leu-Leu- Arg-Asn-Met-Ile-Glu-Met-Ala-Arg-Asn-Glu-Asn-Gln-Arg-Glu-Gln-Ala-Gly-Leu-Asn-Arg-Lys-Tyr-Leu-Asp-Glu-Val-NH2. When the extraction procedure included heating at 100 degrees C for 15 min, UI was cleaved at a highly acid labile Asp-Pro bond to give the fully active UI (4-41). Urotensin I shows close structural and biological homology with the recently isolated ovine hypothalamic corticotropin-releasing factor (CRF) and the frog skin peptide sauvagine and thus may be considered an evolutionary prototype of unique mammalian-hypotensive and vertebrate corticotropin-releasing factors.

Amino Acid Sequence↗
PubMedDate not supplied

Isolation and amino acid sequence of two urotensin II peptides from Catostomus commersoni urophyses.

Two peptides with urotensin II (UII = smooth muscle stimulating) activity have been isolated from urophyses of the sucker, Catostomus commersoni. The amino acid sequences of the two peptides, designated UIIA and UIIB, are as follows: UIIA, H-Gly-Ser-Gly-Ala-Asp-Cys-Phe-Trp-Lys-Tyr-Cys-Val-OH; UIIB, H-Gly-Ser-Asn-Thr-Glu-Cys-Phe-Trp-Lys-Tyr-Cys-Val-OH. These peptides have the part sequence Cys-Phe-Trp-Lys-Tyr-Cys-Val in common with the UII peptide from Gillichthys mirabilis and the part-sequence Phe-Trp-Lys in common with somatostatin.

Amino Acid Sequence↗
PubMedDate not supplied

Iodinated derivatives of vasoactive intestinal peptide (VIP), PHI and PHM: purification, chemical characterization and biological activity.

The iodination of vasoactive intestinal peptide (VIP) was studied, using a variety of enzymatic and chemical iodination methods. Reversed phase high performance liquid chromatography (HPLC) was used to purify the reaction products. The lactoperoxidase-glucose oxidase method gave excellent results in terms of reproducibility, iodine incorporation, and yield of the non-oxidized products [Tyr(I)10]VIP and [Tyr(I)22]VIP, and was used to prepare both 125I and 127I labelled derivatives. In both cases, direct application to HPLC and a single column system were used. Although the oxidized peptides [Tyr(I)10,Met(O)17]VIP and [Tyr(I)22,Met(O)17]VIP could be generated to varying degrees directly by iodination of VIP, these were most conveniently prepared by iodination of [Met(O)17]VIP. Iodinated derivatives of the homologous peptides PHI and PHM were likewise prepared by rapid, one-step HPLC procedures. The site and degree of iodination were determined by HPLC peptide mapping of tryptic digests and amino acid analyses, and in the case of [Tyr(I)10]VIP also by sequencing. The vasorelaxant activities of the iodinated peptides in bovine cerebral artery preparations did not differ significantly from those of the corresponding noniodinated peptides, with the exception of [Tyr(I)10,Met(O)17]VIP and [Tyr(I)22,Met(O)17]VIP which, unlike [Met(O)17]VIP itself, had slightly lower potency than VIP.

Amino Acid Sequence↗
PubMedDate not supplied

Urotensin I- and CRF-like peptides in Catostomus commersoni brain and pituitary--HPLC and RIA characterization.

Two distinct neuronal systems, containing urotensin I-like immunoreactivity (UI-LI) and CRF-LI respectively, have previously been demonstrated immunocytochemically in the brain and pituitary of the teleost Catostomus commersoni. In the present studies, we used HPLC followed by UI- and CRF-RIA to further characterize these UI- and CRF-LI substances. HPLC of Catostomus brain extracts (including extracts modified by dilute H2O2 oxidation or dilute acid cleavage) suggests that the major form of brain UI-LI is very likely identical to the previously characterized urophysial UI; the small amount of pituitary UI-LI is not yet fully characterized. The behavior of brain CRF-LI on reversed phase (RP) extraction suggests that it may exist largely in precursor form. Pituitary CRF-LI, however, behaved as expected for a peptide on RP extraction, and eluted from HPLC as essentially a single (though somewhat broad) peak. The HPLC behavior of pituitary CRF-LI, and its crossreactivity with various CRF antisera, suggest that it represents authentic fish CRF, apparently similar to (but not identical with) human/rat CRF.

Animals↗
PubMedDate not supplied

A vasotocin-like peptide in Aplysia kurodai ganglia: HPLC and RIA evidence for its identity with Lys-conopressin G.

The presence of a vasopressin (VP)- or vasotocin (VT)-like peptide in the central nervous system of the gastropod mollusc Aplysia has been indicated previously. In the case of Aplysia californica, HPLC and RIA evidence suggested the peptide was VT-like but not identical with the nonmammalian vertebrate peptide [Arg8]VT (AVT). In the present study, anterior ganglia extracts from the related species Aplysia kurodai were analyzed by HPLC followed by RIA. Further analysis of the major AVT-IR peak showed it to be indistinguishable, in three distinct solvent systems, from the sea snail venom peptide Lys-conopressin G, but to be different from the vertebrate peptides [Arg8]VP (AVP), [Lys8]VP (LVP), AVT, oxytocin (OT), mesotocin, isotocin, aspargtocin, glumitocin, and valitocin, from the sea snail venom peptide Arg-conopressin S, and from the peptides [Lys8]VT and [Gln8]OT. In addition, the carboxymethylated (CM) A. kurodai peptide had the same HPLC retention time as CM-Lys-conopressin G. The HPLC/RIA results suggest that (i) based on the properties of the solvent systems used, the A. kurodai peptide has two basic amino acids (like the conopressins but unlike the vertebrate peptides), and (ii) there is a high probability that the A. kurodai peptide is identical with Lys-conopressin G.

Amino Acid Sequence↗
PubMedDate not supplied

Early pulmonary vein thrombosis after single lung transplantation.

Pulmonary venous obstruction after single lung transplantation may be mistaken for reperfusion injury or myocardial dysfunction. Complete obstruction of one of the major pulmonary veins will result in hemorrhagic infarction of the affected lobe within 4 to 6 hours, limiting the option of treatment to resection (lobectomy) or retransplantation. Early diagnosis is therefore essential. Transesophageal echocardiography can show the pulmonary venous anastomosis and, combined with color flow and Doppler imaging, offer a quick and reliable method of diagnosis. Prevention of this complication entails harvesting an adequate margin of left atrial tissue around the pulmonary vein orifices, meticulous surgical anastomosis, and the use of anticoagulation in the presence of a thrombogenic tendency in the recipient.

Adult↗