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Biomedical subjects

R B Wilson

Publications and source records attributed to R B Wilson.

At least 109 records · Page 6Linked to original sources
PubMed1978

Vitamin E, antioxidants and lipid peroxidation in experimental atherosclerosis of rabbits.

The purpose of this study was to evaluate the effects of large amounts of dietary vitamin E and butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) in rabbits fed a low-cholesterol, atherogenic diet, and to seek for evidence of lipid peroxidation in the atherosclerotic lesions. Rabbits were fed a purified atherogenic diet, containing butter or the basal diet supplemented with either 1.0% of vitamin E or 0.1% each of BHA and BHT for periods up to 3 years; a negative control group was fed the basal diet with corn oil replacing butter. Aortic and coronary atherosclerosis were more frequent and extensive in rabbits fed either the basal diet or the basal diet supplemented with BHA and BHT than in rabbits fed either the basal diet supplemented with vitamin E or the negative control diet. Dietary vitamin E inhibited atherogenesis by preventing hypercholesterolemia. No evidence of lipid peroxidation was detected in the arterial lesions.

Animals↗
PubMed1977

Dimethylhydrazine-induced colon tumors in rats fed diets containing beef fat or corn oil with and without wheat bran.

Male rats of the Sprague-Dawley strain were fed semisynthetic diets containing either 20% beef fat or corn oil with and without 20% wheat bran. Half of the animals received four weekly doses and the other half received eight weekly doses of dimethylhydrazine, 30 mg/kg, by intragastric intubation. The percentage of rats with tumors of the colon of all types was significantly higher in animals fed no bran than in those fed bran. Likewise, the percentage of rats with polypoid neoplasms of the colon was higher in rats fed no bran, but there was no significant difference in the percentage of rats with malignant tumors of the colon with respect to the feeding of bran. No significant differences were found between rats fed corn oil and those fed beef fat with respect to either the incidence or the kinds of colon tumors. Malignant tumors of the colon, causing death, occurred earlier in rats fed corn oil as compared to those fed beef fat. The percentage of rats with tumors of the colon and the numbers of tumors per tumor-bearing rat were significantly increased in rats given eight doses of dimethylhydrazine or compared to those given four.

Adenocarcinoma↗
PubMed1977

Fetal rat keratinizing epidermal cells in culture: effects of long-term treatment by benzo[a]pyrene on their growth characteristics.

After serial 20-minute trypsinization, skin from near-term fetal MRC rats was separated into epidermis attached to basal lamina and dermis with trapped hair follicles. Fragmentation of the basal lamina by trypsinization caused the epidermal basal cell layer to form cell clumps of various sizes, whereas dermal mesenchymal cells dissociated into single cells, leaving a fibrous network with hair follicles. Clumps of eopdermal basal cells were then isolated with few contaminating hair follicles. At 30-32.5 degrees C, a cornification process caused the clumps to form thickened sheets of nearly pure keratinizing epidermal cells, which were isolated in petri dishes and grew to fill the dishes. The mode of cell differentiation in these sheets resembled an in vivo cornification process; the sheets showed maximum growth at 30 degrees C and failed to survive at 35 degrees C or above. Benzo[a]pyrene (BP) treatment accelerated the growth of cell sheets and enabled them to adapt to 35 and 37.5 degrees C. Keratinizing epidermal cells treated with BP at 35 and 37.5 degrees C were serially subcultured at these temperatures and lost their original dependence on lower temperatures for growth. The cell sheets were still capable of in vitro keratinization; however, some qualitative and quantitative changes were observed.

Animals↗
PubMed1976

Cell interactions between epithelial and mesenchymal components in primary sheets of fetal rat lung cells, and the effects of 3-methylcholanthrene treatment.

Cell rearrangement of epithelial and mesenchymal components was analyzed in primary cell sheets derived from whole lungs from fetal rats and maintained in tissue culture for 3-175 days without being subcultured. A limited reconstruction of original lung tissue from the dissociated cells was observed in these primary cell sheets. From the initial monlayer spread, ciliated columnar epithelial coverage appeared on fibroblast sheets after appoximately 2 weeks' maintence. Cystic formation also developed within the fibroblast layers. Histotypic collagen fibril formation eventually appeared in the fibroblast layers and resulted in the development of multilayered collagenous connective tissue in vitro. Epithelial elements survived as a form of surface coverage during maintenance of the sheets and as cystic structures in the collagenous layers. Treatment with 3-methylcholanthrene induced severe proliferation of epithelial elements in the cell sheets. These proliferative changes included rapid extension of epithelial surface coverage, stratification of immature cells, and squamous cell mataplasia.

Animals↗
PubMed1976

The ultrastructure of oncolytic spores found on pig skin.

A new type of clostridium spore, derived from melanotic hamster tumors treated with pig skin extracts, was examined in a lyophylized form by electron microscopy (EM). Scanning EM indicated that two out of five preparations contained only spores. The spores exhibited oval forms (1.5 X 1.0 MU)with elongated, sometimes infolded, poles indicating an overlying membrane. These structures corresponded to the exosporium as seen by transmission EM. The size of the spores, including the cortex (350-550 A), inner membranes, and cytoplasm averaged 5100 X 5900 A. Cytochemical findings suggest that acid mucopolysaccharides and polypeptides containing N-acetyl-neuraminic acid are localized within the exterior and interior layers of the exosporium and at the surface of the outer coat, which could have a tumor inhibiting effect.

Animals↗
PubMed1976

Pancreatic neoplasms induced in Syrian golden hamsters. I. Scanning electron microscopic observations.

Pancreases from Syrian golden hamsters treated with N-nitrosobis(2-hydroxy-proply)amine for 10 to 25 weeks were examined under scanning electron microscopy (SEM). Findings indicate that the neoplasms originated from the ductal epithelium and developed progressively. Adenomas were lined by epithelium of differing cells types, ranging from a flat singly ciliated form to cuboidal-columnar types, or to mixed cell populations. The epithelial lining of the ductal carcinomas exhibited tubular and papillary cystic spaces, and cell surfaces were similar to the cuboidal and columnar epithelium of adenomas and of ductal epithelial hyperplasia. However, microvilli were dense and of varied lengths. The SEM observations correlated with patterns seen in routine histologic preparations.

Animals↗
PubMed1975

Tissue specificity of nuclear acidic proteins isolated from bovine brain and adrenal medulla.

Nuclear acidic proteins from bovine brain and adrenal medulla demonstrated dissimilar electophoretic and chemical profiles. The amino acid analysis of the acidic nuclear protein fraction isolated from these tissues revealed some variation in the ratio of acidic to basic amino acids. The estimation of free carboxylic acid groups confirmed the more acidic nature of the brain proteins. In comparing the acrylamide gels either visually or optically, several electrophoretically specific bands were apparent. Although the total number of protein bands from each tissue was approximately the same, the adrenal medulla contained a larger proportion of the more positively charged proteins. These observations are interpreted to indicate that the nuclear acidic protein from brain and adrenal medulla may show functional variation.

Adrenal Medulla↗
PubMed1975

Modified thiocarbohydrazide procedure for scanning electron microscopy: routine use for normal, pathological, or experimental tissues.

A modified thiocarbohydrazide (TCH) technique to cross-link osmium layers has resulted in a reliable method for preparing a wide variety of soft biological tissues for scanning electron microscopy without the use of evaported metal. The technique works equally well on tissues with smooth surfaces and those with abrupt changes in contour or cut surfaces, as in biopsy or autopsied material or pathologically altered tissues, and thus has wide applicability. Small surface structures and junctional areas between cells are distinct. In addition, thin cells such as alveolar endothelium in the lung exhibit a transparent property, allowing the visualization of cells within the capillary lumen while retaining adequate contrast for study of the capillary wall itself. Absence of an evaporated metal coat makes the removal of tissue from the scanning electron microscope specimen easy for embedding and examination of the same material with the transmission electron microscope.

Animals↗
PubMed1975

Effect of chronic ethanol ingestion on mitochondrial protein synthesis in Sinclair(S-1) miniature swine.

The effect of chronic ethanol ingestion on hepatic mitochondrial protein synthesis in miniature swine was investigated. After 3 wk on test, there was no decrease in the rate of amino acid incorporation between livers of control and ethanol consuming pigs. After 6 wk on test, there was a 33% decrease in rate of hepatic mitochondrial membrane protein synthesis in livers of experimental pigs, as compared with controls. When analyzed by SDS-gel electrophoresis, a decrease in labeling of the 40,000 mol wt peak, from both whole membrane protein and proteolipid protein profiles, was observed for livers from ethanol consuming pigs as compared with controls.

Animals↗
PubMed1974

Corticosteroid therapy of experimental hydrocephalus after intraventricular-subarachnoid haemorrhage.

Symptomatic hydrocephalus after subarachnoid haemorrhage seems to result both from mechanical obstruction of arachnoid villi and basilar cisterns and from an inflammatory cellular reaction in the villi. Subarachnoid haemorrhage was induced in rabbits using whole blood injected through an implanted intraventricular needle. Control rabbits receiving intraventricular methyl prednisolone acetate but no blood, developed ventricular dilation significantly more often than untreated controls. Eighty-three per cent of rabbits with untreated experimental subarachnoid haemorrhage developed moderate to severe hydrocephalus. Intramuscular steroid therapy significantly reduced the incidence of hydrocephalus.

Animals↗