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Biomedical subjects

R B Wilson

Publications and source records attributed to R B Wilson.

161 records · Page 9Linked to original sources
PubMed1962

IN VIVO AND IN VITRO OBSERVATIONS OF LEPTOSPIRA POMONA BY ELECTRON MICROSCOPY.

Miller, Norman G. (University of Nebraska College of Medicine, Omaha) and Richard B. Wilson. In vivo and in vitro observations of Leptospira pomona by electron microscopy. J. Bacteriol. 84:569-576. 1962.-Leptospira pomona 3341 was observed by electron microscopy, after the preparation of thin sections from culture material and from infected hamster tissue. The external membrane of low electron density envelops the entire leptospire and appears to be quite flexible, as suggested by its many folds. The spiral protoplasmic body is tubular in structure with a relatively dense wall and a central area of low electron density. Occasionally, very dark circumscribed bodies were seen imbedded in the protoplasmic wall. Detailed morphology is presented of a knoblike structure located at the end of the axial filament. Bifurcation of the axial filament could be demonstrated in leptospires from cultures. Leptospires were observed free or enclosed in vesicles within the cytoplasm of liver parenchymal and renal tubule cells. Erythrocytes located in kidney tissue also contained leptospires within the cytoplasm. The appearance of intracellular leptospires is much the same as those seen extracellularly or from culture.

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Homocysteine theory of arteriosclerosis.

Arteriosclerotic plaques were found in the aorta and arteries of rabbits given homocysteine thiolactone, methionine or homocysteic acid, both parenterally and in a synthetic diet. Animals given large doses of parenteral methionine or homocysteine thiolactone died of pulmonary embolism and pulmonary infarct. Pyridoxine prevented thrombosis and pulmonary embolism but did not prevent arteriosclerotic plaques. These findings and previous work, showing a new matabolic pathway for sulfate ester synthesis from methionine, the somatotrophic activity of homocysteic acid, and control of cellular growth and intercellular matrix synthesis by homocysteine derivatives, suggest a theory to explain aspects of the pathogenesis of arteriosclerosis.

Animals↗
PubMedDate not supplied

Atherosclerosis in rabbits fed a low cholesterol diet for five years.

Rabbits were fed a low cholesterol atherogenic diet for up to 5 years. Arterial lesions during the first 12 months consisted of smooth muscle cell and lipid accumulation in the intima, with smaller amounts of elastin and collagen. By 24 months, considerable degeneration and necrosis of smooth muscle foam cells had occurred, lipid had decreased in relative proportion, and collagen was predominant. These trends continued during the final 3 years. By 48 months most plaques were calcified and a few had hemorrhage. Atherosclerosis was extensive in rabbits with serum cholesterol concentrations greater than 300 mg/100 ml and minimal in rabbits with concentrations consistently less than 150 mg/100 ml. Thicker lesions tended to have more atheromas while thinner ones were more fibrous and less fatty. Significant regression of fatty streaks occurred in a group of rabbits fed the atherogenic diet for 2 years and a stock diet during the third year but more advanced lesions did not regress. This study illustrates the importance of time as a variable in atherogenesis, and demonstrates that modest hypercholesterolemia can lead to atherosclerosis in rabbits that is qualitatively unlike atherosclerosis induced in rabbits by cholesterol rich diets and that resembles several stages of human atherosclerosis.

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Atherosclerosis and myocardial ischemic lesions in alloxan-diabetic rabbits fed a low cholesterol diet.

To reinvestigate the relationship between diabetes and atherosclerosis in rabbits, we fed alloxan-diabetic, alloxan-nondiabetic, and control rabbits a low cholesterol atherogenic diet for up to 40 weeks. Concentrations of plasma total cholesterol, phospholipids, and triglycerides were higher, the percentage of very low density lipoproteins was higher, and the percentage of high density lipoproteins was lower in diabetic than in nondiabetic rabbits. Smooth muscle cell proliferation was prominent, atherosclerosis was more extensive, and a high incidence (29%) of large, sharply demarcated, ischemic myocardial lesions occurred in the diabetic rabbits. These results are in contrast to those of earlier studies where the diabetic state resulted in a partial protection against atherogenesis in alloxan-diabetic rabbits fed larger amounts of cholesterol.

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Mucinous oligodendroglioma of the spinal cord in a dog.

Intraspinal neoplasia in the dog is relatively rare and may be classified according to the location of the tumor. Extradural tumors are situated outside the dura mater. Intradural tumors may be subdivided into two classes, depending upon whether the tumor is located outside the spinal cord in the subdural space (intradural extramedullary) or within the spinal cord substance (intramedullary). Intramedullary tumors are the least commonly reported spinal cord tumors; most primary intramedullary tumors are astrocytomas, ependymomas, or oligodendrogliomas. Reported here are the clinical, radiographic, and pathological findings associated with a spinal cord oligodendroglioma in a dog.

Animals↗
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Necrotizing hepatitis associated with a reo-like virus infection in a parrot.

A young African grey parrot was presented for necropsy following a 3-to-4-day illness consisting of lethargy, anorexia, and diarrhea. A disseminated necrotizing hepatopathy was evident upon histologic examination of the liver. Aggregates of approximately 70-nm-diameter viral particles having morphology consistent with the family Reoviridae were demonstrated by thin-section and negative-staining electron microscopy.

Animals↗
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Pineoblastoma in a cockatiel.

Pineoblastoma, a primitive neoplasm of pineal gland origin, was diagnosed in a cockatiel based on gross, histopathological, and electron-microscopic findings.

Animals↗
PubMedDate not supplied

Hepatic hemosiderosis and Klebsiella bacteremia in a green aracari (Pteroglossus viridis).

A green aracari (Pteroglossus viridis) was presented for necropsy after being found dead; no previous clinical signs had been noted. Microscopic examination revealed multifocal necrosis of the liver, spleen, and lung compatible with an acute bacteremia. Klebsiella pneumoniae was isolated from the liver, kidney, and intestine. Histopathological and toxicological findings also reflected a concurrent hepatopathy due to excess iron accumulation. Hepatic hemosiderosis has been reported in mynahs, birds of paradise, and quetzals but has not previously been reported in the green aracari.

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