Biomedical subjects
Publications and source records attributed to M H Wheeler.
The net ionic fluxes of H+ and Na+ were examined in Heidenhain pouches during damage with sodium taurocholate solution. The increase in ionic flux which occurred with taurocholate could be prevented in animals given H1 and H2 histamine antagonists in combination. The results suggest that histamine mediates changes in the transmucosal ionic flux produced by bile acid.
In four canine Heidenhain pouches the net fluxes of H+ and Na+ have been examined before, during, and after instillation of sodium taurocholate into the pouch. These experiments were conducted in animals given H1 (mepyramine maleate) and H2 (metiamide) histamine antagonists, alone and in combination. Control experiments without antagonists were also conducted. In control experiments, as well as in those using the histamine antagonists separately, the usual sequence of events followed exposure to taurocholate-that is, a gain in the volume of the solution in the pouch and an increase in the fluxes of Na+ and H+ across the mucosa. In experiments in which H1 and H2 histamine antagonists were used in combination, taurocholate had very little effect on the ionic fluxes of H+ and Na+, suggesting that changes in the ionic permeability of the gastric mucosal barrier are mediated by histamine through both H1 and H2 receptor sites.
The history of the technique of promoting dissolution of retained gallstones in the biliary tree is briefly reviewed. Present methods are described in detail and our own experience recorded. We have treated six patients with retained calculi by means of heparinized saline and sodium cholate infusions of the common bile duct. Successful dissolution of calculi was achieved in five cases, but one patient developed severe pancreatitis and renal failure which responded to peritoneal dialysis. We believe that the method is a valuable alternative to re-exploration of the common bile duct, particularly when calculi are situated in the distal part of the duct.
The gastric mucosa in four canine Heidenhain pouches was damaged with sodium taurocholate in a concentration which was just sufficient in each dog to produce consistent changes. Solutions were placed in the pouches and changes in the volume, concentrations, and fluxes of both hydrogen ion and sodium ion were measured before and during exposure to taurocholate. Changes which occurred with taurocholate were compared with control periods; taurocholate caused a relative increase in volume of 1 ml and approximately a fourfold increase in the hydrogen ion and sodium ion concentrations and the sodium ion flux. Changes in the hydrogen ion flux were smaller and, in some experiments, insignificant. Change in the hydrogen ion flux is less sensitive than the other parameters as an indicator of minimal mucosal damage.
A prospective randomized trial of wound drainage has been performed in a series of ninety-two patients undergoing one hundred breast biopsies. The overall incidence of wound hematoma was 14 per cent but the insertion of a wound drain did not protect against the development of wound hematoma. The wound infection rate was 1 per cent.
Transmission and scanning electron microscopy showed that melanin of wild-type Verticillium dahliae occurred as granules in microsclerotial cell walls and in a fibrillar network encapsulating the walls. An albino microsclerotial mutant and a brown microsclerotial mutant of V. dahliae did not form melanin granules. When albino microsclerotia were treated with (+)-scytalone (a metabolite that the brown mutant accumulates), they formed melanin granules and turned black. These granules were similar in appearance and distribution to those in the wild type. Melanin granules of the wild-type isolate and the scytalone-treated albino mutant were formed at a maximum rate in microsclerotia from 5- to 8-day-old cultures. These observations suggest that scytalone is a natural intermediate of melanin synthesis in V. dahliae.
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We have studied a series of 22 human medullary carcinomas (MCTs), both primary and metastatic, using immunocytochemistry (ICC) to localize calcitonin and somatostatin peptide and in situ hybridization (ISH) to localize calcitonin and somatostatin mRNA. All tumors were positive for calcitonin peptide with ICC, which often showed considerable intercellular heterogeneity, with many cells having undetectable levels of calcitonin. However, calcitonin mRNA localized by ISH was much more uniformly distributed, indicating that MCT tumor cells may retain the capacity to both synthesize and store calcitonin, whereas others lose their storage but not their synthetic capacity. Somatostatin peptide and mRNA were found in tumors from 15 patients. In contrast to the pattern seen with calcitonin, somatostatin mRNA and peptide were usually found in single scattered cells. When correlation was possible, the same cell showed positivity for somatostatin mRNA on ISH and positivity for somatostatin peptide on ICC. However, in one tumor many more cells were positive for mRNA than for peptide, suggesting that only a proportion of cells retained the ability to store the peptide. The variation in cellular content of immunoreactive calcitonin is interpreted as resulting from either an increased tumor growth rate or reduced ability to store peptide in a less differentiated tumor. With somatostatin there was good correlation between mRNA and peptide content, but it occurred in single widely scattered cells, most tumor cells being negative for both peptide and mRNA. It is suggested that somatostatin production might be associated with a reduction in the growth of the cell concerned, either through a differentiation step or through a direct effect of the hormone.(ABSTRACT TRUNCATED AT 250 WORDS)