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Biomedical subjects

S M Morris

Publications and source records attributed to S M Morris.

At least 163 records · Page 9Linked to original sources
PubMed1983

Autoradiographic study of 3H-methylated elastase in hamster lungs.

An emphysemalike condition can be induced in animal lungs by the instillation of a single dose of elastase. Autoradiography was used to determine the location of 3H-methylated porcine pancreatic elastase in hamster lungs at four time points. Six hours after instillation of radiolabeled enzyme the distribution of silver grains was very patchy, but in heavily labeled areas grains were concentrated over macrophages, connective tissue areas and over some fibroblasts. By 24 hr the labeling of connective tissue areas was no longer evident and almost all silver grains were associated with macrophages or with the edema fluid that filled many alveoli at this time. By 4 days only macrophages exhibited concentrations of silver grains. The labeling of macrophages was still evident at 7 days. Elastase inactivated by N-acetyl-(L-alanyl)3-L-alanine chloromethyl ketone showed a different distribution 6 hr after instillation. Silver grains were concentrated over macrophages and alveolar type II cells but showed no affinity for connective tissue areas or fibroblasts. By 24 hr almost all grains were located over heavily labeled macrophages.

Animals↗
PubMed1982

Molecular cloning of gene sequences for avian fatty acid synthase and evidence for nutritional regulation of fatty acid synthase mRNA concentration.

A double-stranded cDNA library was constructed using total poly(A)+ RNA from the goose uropygial gland. Clones containing sequences complementary to fatty acid synthase mRNA were initially identified by colony hybridization with a 32P-labeled cDNA transcribed from RNA enriched for fatty acid synthase mRNA. Identity of the fatty acid synthase clones was confirmed by hybrid-selected translation. Mature fatty acid synthase mRNA is approximately 16 kilobases in length. When unfed neonatal goslings were fed for 24 hr, relative synthesis of hepatic fatty acid synthase increased more than 42-fold. Concomitantly, hepatic fatty acid synthase mRNA levels increased 70-fold. Thus, nutritional regulation of the synthesis of hepatic fatty acid synthase probably occurs at the pretranslational level. The availability of a specific probe for fatty acid synthase mRNA should allow us to analyze the regulation of expression of this gene during development, by nutrition and by hormones in both liver and uropygial gland.

Animals↗
PubMed1982

Induction of mutations and sister-chromatid exchanges in Chinese hamster ovary cells by ethylating agents.

Chinese hamster ovary (CHO) cells were exposed to [3H]ethyl nitrosourea (ENU) or [3H]ethyl methanesulfonate (EMS) and the following DNA ethylation products were quantitated: 3- and 7-ethyladenine, O2-ethylcytosine, 3-, 7- and O6-ethylguanine, O2- and O4-ethyldeoxythymidine and the representative ethylated phosphodiester, deoxythymidylyl (3'-5')ethyl-deoxythymidine. When mutations at the hypoxanthine-guanine phosphoribosyl transferase (HGPRT) locus induced by these same treatments were compared with the observed ethylation products, mutations were found to correlate best with 3- and O6-ethylguanine. EMS induced approximately twice as many sister-chromatid exchanges (SCEs) as ENU at doses yielding equal mutation frequencies. When SCEs were indirectly compared with DNA ethylation products, 3-ethyladenine and ethylated phosphodiesters related best to SCE formation. Because mutation and SCE induction appear, at least in part, to be related to different DNA adducts, SCE induction by simple ethylating agents may not be a quantitative indicator of potentially mutagenic DNA damage.

Animals↗
PubMed1982

A method for preparing chromosomes from peripheral blood of the mouse.

A modified Triman et al. (1975) procedure for preparing metaphase chromosomes from mouse peripheral blood is described. Modifications include: isolation of white blood cells using a ficoll-hypaque gradient; seeding cultures with a known concentration of leucocytes such that the PHA/cell concentration can be controlled for optimum stimulation through 72 h with no media change; and visual monitoring of cell growth to determine when there should be sufficient numbers of dividing cells for harvest and thus eliminate unnecessary harvest of non-productive cultures. We have found this modified procedure to be highly reproducible with the final 0.5 ml fixed cell suspension yielding 50-75 quality metaphase spreads per drop.

Animals↗
PubMed1981

Ultrastructural changes in hamster lung four hours to twenty-four days after exposure to elastase.

A single endotracheal instillation of elastase initiates a series of changes in animal lungs that results in a condition resembling human panlobular emphysema. An ultrastructural examination of this series of changes was conducted on the lungs of male golden hamsters exposed to 3H-methylated pancreatic elastase and sacrificed at intervals between 4 hour and 24 days after exposure to enzyme. Lung tissue between 4 and 48 hours showed evidence of hemorrhage and progressive degradation of elastic fibers. Very little indication of epithelial cell damage accompanied these changes. Four days after exposure to elastase, synthesis of new elastic fibers began with the appearance of small clumps of microfibrils in close association with interstitial cells, fibroblasts, and smooth muscle cells. There was also evidence of alterations in alveolar type II cells at this time. Small fibrillar elastic fibers continued to be present in the lung through twenty-four days and may represent a slow repair process or may indicate a structural difference in elastic fibers synthesized after exposure to elastase. Evidence of the continued degradation of elastic fiber could be found up to 16 days after exposure to elastase, revealing that repair processes were occurring in some areas of the lung while destructive process still predominated in other areas.

Animals↗
PubMed1981

Superoxide dismutase, catalase, and glutathione peroxidase in the swim bladder of the physoclistous fish, Opsanus tau L.

The antioxidant enzymes superoxide dismutase, glutathione peroxidase, and catalase were measured in the rete mirabile and gas gland epithelium area of the swim bladder of the toadfish Opsanus tau. When the concentration of enzyme in the swim bladder was compared with the concentration in other organs (kidney, heart, gills) of the same fish, the swim bladder was found to have the highest concentration of superoxide dismutase but relatively low levels of glutathione peroxidase and catalase. Cytochemical assay for the peroxidatic activity of catalase confirmed that virtually no catalase is present in epithelial cells of the gas gland. A similar assay for peroxidase revealed a cyanide-sensitive peroxidase in the multilamellar bodies of these cells. Most of the catalase and peroxidase in the rete mirabile appears to be confined to the granules of neutrophils and the cytoplasm of erythrocytes. Enzyme activity in the neutrophils is not inhibited by 10(-1) M KCN. Cyanide does not appear to inhibit the peroxidase activity in erythrocytes but has little effect on catalase in these cells.

Air Sacs↗
PubMed1981

Complement-mediated solubilization in patients with systemic lupus erythematosus, nephritis or vasculitis.

Solubilization of an immune precipitate by serum is a complement function mediated by the alternative pathway and enhanced by the classical pathway--it therefore provides the basis of a simple quantitative assessment of the integrity of complement function. Using a preformed radiolabelled precipitate of BSA-alpha BSA Ab, the solubilization capacity of serial sera from 75 patients with various immune complex diseases or diseases associated with hypocomplementaemia was investigated to correlate this assay of complement function prospectively with disease activity and with measurements of circulating immune complexes (CIC). Reduction in solubilization, defined by more than 25% of values in a given patient being below the normal range, was found in 11 of 12 patients with active SLE, two of 19 patients with active systemic vasculitis, three of three patients with post-streptococcal glomerulonephritis and in three of six patients with nephrotic syndrome due to other types of nephritis. In serial studies, solubilization correlated with disease activity in patients with SLE (P less than 0.005), systemic vasculitis (P less than 0.05) and post-streptococcal glomerulonephritis (P less than 0.05). CIC were found more frequently than abnormalities in solubilization; however, the solubilization assay identified a population of patients with CIC more likely to have active disease. This simple assay of complement function provides data on an aspect of immune complex disease not readily apparent from standard estimations of circulating immune complexes, and appears to be a better measure of their potential phlogistic effects.

Adult↗
PubMed1979

Ultrastructure of the swim bladder of the goldfish, Carassius auratus.

The swim bladder of the cyprinid Carassius auratus (goldfish) is a two-chambered organ connected to the esophagus by a pneumatic duct. The anterior chamber is lined by a single type of squamous epithelial cell. Two types of epithelial cells are present in the posterior chamber. Flattened cells with differences in the electron density of the cytoplasm line most of the chamber. Darker cells generally contain large amounts of glycogen. Cuboidal epithelial cells also occur in the posterior chamber. A glandular layer external to the muscularis in the posterior chamber is composed of large cells containing little glycogen, an extensive Golgi apparatus, and numerous mitochondria with single large granules. Capillaries and nerves are present in large numbers in this layer. Blood vessels form micro-retia mirabilia in the submuscular layer external to the glandular layer. Vessels are of two distinct types with wide lumina and flattened endothelium characterizing the venous vessels. Arterial vessels and have smaller lumina, thick endothelial cells with prominent pinocytotic vesicles, and surrounding pericytes. Collagen is present in three forms in this swim bladder - large tactoids in the tunica externa of the anterior chamber, smaller tactoids in the lamina propria of the posterior chamber, and small fibrils in all other areas.

Air Sacs↗
PubMed1979

Cell-free translation and thyroxine induction of carbamyl phosphate synthetase I messenger RNA in tadpole liver.

Total RNA of tadpole and frog (Rana catesbeiana) liver was isolated by either 7 or 8 M guanidine . HCl extraction and translated in a cell-free protein-synthesizing system derived from rabbit reticulocytes. The identity of carbamyl phosphate synthetase I[carbamoyl-phosphate synthase (ammonia); ATP:carbamate phosphotransferase (dephosphorylating), EC 2.7.2.5] synthesized in vitro with the purified enzyme was established as follows: (i) immunoprecipitation by a specific antibody; (i) comigration with purified carrier enzyme on sodium dodecyl sulfate/polyacrylamide gel electrophoresis; (iii) copurification with carrier enzyme by affinity chromatography on Cibacron Blue F3GA-coupled agarose; and (iv) formation of identical proteolytic cleavage products. Inclusion of protease inhibitors in the system resulted in no apparent change in the polypeptide molecular weight. These results indicate that carbamyl phosphate synthetase I is synthesized as a polypeptide that is indistinguishable from the mature enzyme by the analytical methods used and that it is not grossly modified during its transport into mitochondria. The level of translatable mRNA for carbamyl phosphate synthetase-I in tadpole liver was increased about 2-fold 1 day after thyroxine treatment and did not change significantly through 4 subsequent days of treatment. Thus the thyroxine-induced synthesis of carbamyl phosphate synthetase I in tadpole liver is at least partly due to an increase of translatable mRNA for this enzyme.

Animals↗
PubMed1979

Aspirin-stimulated intestinal electrolyte transport in rabbit ileum in vitro.

Because aspirin and the heavy metal salts of related anions have effects on intestinal ion transport and on diarrheal states, we have studied the effect of aspirin (ASA) on the in vitro rabbit ileum in an attempt to understand its mechanism of action. Ten millimolar of aspirin increased the conductance of rabbit ileum by 10--50% but did not change the permselectivity of the shunt path as determined by measurement of diffusion potentials. In Cl-free and HCO3-free solutions, aspirin reduced both Na absorption and the short-circuit current (Isc), which suggests an effect on electrogenic Na transport. Such an effect was not unexpected, since aspirin interferes with ATP production. However, in Ringer solution, aspirin in concentrations as little as 1 mM in the serosal solution reduced the Isc as before but also stimulated Na and Cl absorption and reduced JRnet (? HCO3 secretion) to zero. Aspirin had no effect on Na transport in the absence of Cl and no effect on Cl transport in the absence of Na, which suggests that aspirin stimulated a coupled transport process. Although these effects of ASA resemble those of alpha-adrenergic agents, ASA's effect was not blocked by alpha-adrenergic blockers such as phentolamine or phenoxybenzamine. The exact mechanism of ASA-stimulated NaCl absorption remains to be determined.

Adrenergic alpha-Antagonists↗