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Biomedical subjects

R T Bronson

Publications and source records attributed to R T Bronson.

At least 163 records · Page 9Linked to original sources
PubMed1981

Noma in a nonhuman primate.

A lesion in Macaca cyclopis which appears to conform to defined characteristics of noma in human beings has been reported. Clinical features in common include the gangrenous appearance of the lesion, the association with necrotizing ulcerative gingivitis, and the massive destruction of soft tissue and bone in the oronasofacial regions. Systemic features in common include debilitation of the host, leukocytosis, and depression of cellular immunologic responses. Microbiologic studies revealed the presence of organisms commonly found in necrotizing ulcerative gingivitis. The detection of true noma in nonhuman primates may now allow the opportunity for study of the etiology, pathophysiology, and therapy of this condition for human benefit.

Animals↗
PubMed1981

Ultrastructure of macrophages and karyolytic bodies in small intestinal villi of macaque monkeys and baboons.

Macrophages in the lamina propria at the tips of small intestinal villi in 41 of 51 macaque monkeys were filled with eosinophilic, autofluorescent, periodic acid-Schiff-positive globules, hematoxyphilic and Feulgen-positive granules, vacuoles, and iron and lipochrome pigments. The Feulgen-positive granules were seen ultrastructurally in macrophages of nine of 15 clinically normal macaques and baboons. Four of the 15 had similar granules in the intercellular spaces of the epithelium. Ultrastructurally, the eosinophilic globules were electron-dense phagolysosomes; the Feulgen-positive granules resembled nuclei of lymphocytes in various stages of pyknosis. Cytoplasmic organelles enclosed in membrane-bound vacuoles were present in the intercellular spaces of the epithelium of one monkey. Similar organelles were phagocytized by macrophages in another monkey. Feulgen-positive granules have been reported in villi of normal rodents. In all other species, including man, degenerating nuclei called "karyolytic bodies" and other evidence of enterocyte or lymphocyte degeneration have been considered abnormal concomitants of irradiation and antimitotic therapy. The significance of the findings in monkeys is not known, but they may represent a subclinical disease process.

Animals↗
PubMed1981

Nephritis and hemolytic anemia in owl monkeys (Aotus trivirgatus).

The two most common diseases of captive owl monkeys (Aotus trivirgatus) are hemolytic anemia and glomerulonephritis. The anemia is characterized by total red blood cell counts between 0.45 and 3.44 x 10(6) microliters, hemoglobin values as low as 1.0 g/dl, and many circulating nucleated red blood cells. Centrilobular necrosis in the liver, extramedullary hematopoiesis in liver and spleen, and hemoglobin casts in kidney tubules are prominent histologic features. Hemosiderin and lipofuscin often are found in liver, spleen, kidney and lymph nodes. Microthrombi and microinfarcts sometimes are scattered throughout the brain. Glomerular lesions in Aotus have been described previously and are characterized by increased numbers of mesangial cells and matrix, glomerulosclerosis and electron dense deposits in basement membranes. Lymphocytes, plasma cells and eosinophils frequently are present in the interstitium. In the early stages the cellular infiltrate is periglomerular. The foci then grow to encompass adjacent glomeruli and tubules. Finally, large portions of the kidney are affected and connective tissue proliferates. The incidence of extramedullary hematopoiesis in the liver correlated significantly with that of interstitial nephritis (0.001 less than p less than 0.01) but not with glomerular lesions. The two kidney lesions, glomerulonephritis and interstitial nephritis correlated strongly in incidence. They also found with equal frequency in 87 monkeys with clinical evidence of anemia. This analysis indicates that there may be no common pathogenesis of the hematologic and renal abnormalities as seen in certain autoimmune diseases. However, there could be complex interactions between two or more disease mechanisms that account for the various manifestations of disease.

Anemia, Hemolytic↗
PubMed1981

Colonic adenocarcinoma associated with chronic colitis in cotton top marmosets, Saguinus oedipus.

Colitis is a common disease of cotton top marmosets, Saguinus oedipus, characterized by crypt abscesses and inflammation of lamina propria. In more advanced colitis there is marked irregularity of mucosal surface, distortion of crypt architecture and epithelium, increased numbers of mitoses, and decreased numbers of goblet cells. Foci of pleomorphic cells arranged in poorly formed glands or sheets, interpreted as carcinoma in situ, also occur. Many such cases have invasive colonic adenocarcinoma with metastasis to colonic lymph nodes but not elsewhere. Analysis of necropsy data from a group of 210 marmosets in captivity for 3.5 yr revealed that the incidence of advanced colitis, adenocarcinoma in situ and invasive carcinoma increased markedly over that period. A strong association between colitis and adenocarcinoma was suggested by both morphologic and epidemiologic data.

Adenocarcinoma↗
PubMed1981

Nutritional evaluation in cotton-top tamarins (Saguinus oedipus).

Four cotton-top tamarins were fed a commercial biscuit diet and three others a commercial canned diet for 12 weeks. Thereafter, all seven were fed a purified diet for 12 weeks. General health, body weight, food intake, fecal output, serum biochemistry, blood count, and colonic histopathology were evaluated at various times during the experiments. The diets did not affect these parameters except the purified diet was associated with relatively reduced fecal output. Diarrhea and chronic colitis occurred independently of the diet in three tamarins in the course of the study.

Animals↗
PubMed1981

Computer-based animal record system in a nonhuman primate colony.

A relatively inexpensive microcomputer system was developed to store and manipulate clinical and pathologic data from a large colony of nonhuman primates. The programming for the system was designed so that the computer instructs users, who may have no knowledge of programming, how to enter data of all kinds and how to to command it to answer any ad hoc queries about the data. Minimum input from a professional programmer is required. As many as 4 investigators may use the system simultaneously by means of satellite terminals located in several areas throughout the facility. Most alphabetic data are coded, using 2- or 3-digit codes. More complex diagnostic data are coded, using the numeric codes of the Systematized Nomenclature of Medicine. presently, 17 record types encompasses all data entered into the computer. The system is functionally designed and about 50% operational at this time. This is the first description of an animal medical data system designed to exploit the lower costs and increased power of commercially available microcomputer packages.

Animals↗
PubMed1980

Protein-losing enteropathy in six macaques.

Using intravenous administration of radioactive labeled chromic chloride, which binds to plasma proteins, protein-losing enteropathy was documented in 6 macaques (Macaca mulatta and Macaca arctoides) with progressive weight loss and hypoalbuminemia. Four clinically normal macaques lost 0.5% +/- 0.1% of the label in feces over 4 days, compared with the diseased macaques, which lost from 1.0%--14.2% of the dose during the same period. Lesions in the small intestine (lymphangiectasia, amyloidosis of lamina propria, mast cell proliferation in the tunica muscularis and submucosa, and goblet cell hyperplasia) were associated with the protein-losing enteropathy.

Animals↗
PubMed1980

Morphology and morphogenesis of cerebral ring hemorrhages in anemic monkeys.

Cerebral ring hemorrhages were observed in four species of monkeys with various forms of anemia. The lesions resembled those described in humans with a variety of diseases, including pernicious anemia. The pale centers of most lesions were surrounded by rings of erythrocytes. Also observed were petechiae, pale foci without hemorrhage, and glial nodules. Ultrastructural study revealed that the pale cores were foci of degenerating neurites associated with infiltration of fibrin into the finest interstitial spaces. Leakage of firbinogen and erythrocytes apparently occurred from capillary sized vessels. A few of these were thrombosed, some were normal and some had only small fibrin thrombi in apparent apposition to damaged endothelial tight junctions. These findings suggest that a primary effect of anemia and other insults associated with ring hemorrhages is damage to tight junctions. Consequent fibrinous exudation clogs the interstitium and results in neuritic degeneration.

Anemia↗
PubMed1980

Necrotizing myopathy associated with hemolytic anemia in owl monkeys (Aotus trivirgatus).

In 40 owl monkeys with hemolytic anemia of unknown etiology, 37 had a myopathy characterized by focal or diffuse necrosis of sarcoplasm which was eosinophilic and floccular. Phagocytosis of necrotic fibers and regenerative changes were also observed. The severity of lesions roughly paralleled the severity of anemia and of centrilobular hepatic necrosis assumed to be caused by hypoxia. That the myopathy was not caused by anemia per se was suggested by the finding of mild myopathy in 10 of 24 monkeys known never to have been severely anemic. Although anemic owl monkeys are known not to be deficient in either vitamin E or selenium, parenteral vitamin E is partially protective against hemolysis in this species. The myopathy, which resembled that caused by vitamin E or selenium deficiency in other species, is probably the result of a metabolic abnormality involving vitamin E in an unknown way.

Anemia, Hemolytic↗
PubMed1980

Spontaneous pallido-nigral accumulation of iron pigment and spheroid-like structures in macaque monkeys.

Common incidental pathologic findings in Old World monkeys are spheroid-like structures and iron pigment in the substantia nigra and globus pallidus. The occurrence of each finding correlates with the number of years monkeys have spent in captivity. The spheroids are eosinophilic and argyrophilic, but are generally PAS, iron, and luxol fast blue negative. Ultrastructurally, they consist of aggregations of dense globules and granules interspersed with membranes; normal organelles are absent. One classic spheroid with a thin myelin sheath and accumulated fibrillar material was observed. The material in spheroids is ultrastructurally distinguishable from iron pigment, which is present in glial cells, and from neuronal lipofuscin. Accumulation of spheroids and iron pigmentation may be age-related phenomena involving portions of the brain with shared anatomical and biochemical characteristics. The study of these changes may shed light on the pathogenesis of such spheroid degenerations as Hallervorden-Spatz disease.

Animals↗
PubMed1980

Therapeutic efficacy of vitamin E and selenium in treating hemolytic anemia of owl monkeys (Aotus trivirgatus).

The roles played by vitamin E and by selenium in the anemia of owl monkeys were studied by injecting a mixture of the two antioxidants in 17 anemic monkeys. The result was an increase in mean hemoglobin concentration from 8.6 +/- 2.2 to 11.9 +/- 2.5 g/dl; in 1o of these monkeys with typically elevated numbers of circulating nucleated erythrocytes, the mean number of such cells per 10(2) leukocytes declined from 50.1 +/- 49.9 to 0.6 +/- 1.2. Injections of vitamin E alone in eight monkeys were less consistently effective; selenium administered alone to nine monkeys had no therapeutic effect. Neither anemic nor normal owl monkeys were deficient in serum vitamin E, plasma selenium, erythrocyte glutathione peroxidase or other related erythrocyte enzymes. Oral administration of vitamin E brought about no increase in serum levels of the vitamin, but hemolysis of erythrocytes in dialuric acid decreased from 18.6 +/- 15.8% to 1.0 +/- 0.03%. Selenium therapy brought about increased plasma selenium in two of three experiments, but glutathione peroxidase, which is selenium dependent, did not increase.

Administration, Oral↗
PubMed1979

Brain weight-body weight scaling in breeds of dogs and cats.

Autopsy data from 2,100 pet dogs are used to demonstrate that mean brain weight (y) in 26 breeds of dogs is related to mean body weight (x) by the function y = 0.39 x 0.27. Power functions with the exponent 0.27 appear to define intra-species brain-body weight scaling in several other species. These functions may serve as base lines for measuring increases or decreases in encephalization during species evolution. Curiously, averaged data from 1,250 domestic cats of 2 breeds can be plotted on a line with slope of 0.67, which is known to define inter- rather than intra-species brain-body weight scaling among mammals.

Anatomy, Comparative↗
PubMed1978

A contribution to the electron microscopic morphometric analysis of peripheral nerve.

Several aspects of data collection and analyses of peripheral nerve experiments employing light and electron microscopic morphometric techniques have not been adequately discussed in the literature. From statistical tests performed on nerve data, it was found that light compared with electron microscopic morphometry underestimates the number of small fibers. An optimum sampling strategy must take into account a potential bias toward small fibers introduced by measuring fibers from electronmicrographs. It must also take into account a potential bias introduced by the non-random distribution of nerve fibers of different sizes in nerves. These biases are offset by sampling a large enough number of fibers from large enough area electron micrographs. A method is presented for analysing periopheral nerve data using the nested analysis of variance. This requires first dividing the usual bimodal nerve fiber distribution into component normally distributed parts. The number of fibers in the two portions of a bimodal distribution must be considered in data analysis. Knowledge of the variances of parameters to be studied in any particular nerve is necessary for optimum sampling strategies.

Animals↗
PubMed1977

Morphometric analysis of the effects of exenteration and enucleation on the development of third and sixth cranial nerves in the rat.

The effects on rat cranial nerve growth of removing various amounts of extraocular muscle was studied using morphometric techniques. Growth in the third cranial nerves was found to be severely retarded when most of the muscle tissue was removed. By contrast, removal of the eye alone, leaving extraocular muscles relatively intact, was found to have little or no effect on the subsequent growth of third and sixth cranial nerve fibers and of extraocular muscle fibers. This conclusion could be drawn only through the application of statistical methods which take into account several generally unrecognized facts: frequency distributions of axon circumference and myelin sheath thickness are highly variable from nerve to nerve even in normal rats, which often have more large fibers in left than in right nerves. The bimodal nature of peripheral nerve fiber distributions precludes the use of such parametric tests as the commonly and inappropriately used t-test, but a non-parametric test such as the Kolmogorov-Smirnov test, extensively used in these studies, is inadequate for data comprising several sets of distributions to be compared. The application of the analysis of variance to some of the data and the merits of the procedure are discussed.

Abducens Nerve↗
PubMed1977

Inherited necrotizing myelopathy of Afghan hounds.

Eleven examples of a naturally occurring, adolescent-onset spinal cord necrosis in Afghan Hounds were studied. Unusual and characteristic spinal cord lesions were necrosis and small vessel proliferation in the dorsal and ventro-medial spinal cord white matter extending from caudal cervical segments to cranial lumbar segments. Spinal cord gray matter and dorsal and ventral roots were preserved. Four dogs had histologically similar lesions in the superior olivary nucleus. The cause of these lesions was not determined by histopathologic or ultrastructural examination. Chi-square analysis of pooled sibships indicates a simple autosomal recessive mode of inheritance.

Animals↗