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Biomedical subjects

C F Simpson

Publications and source records attributed to C F Simpson.

At least 73 records · Page 4Linked to original sources
PubMed1978

Cyclic thrombocytopenia induced by a Rickettsia-like agent in dogs.

Hematologic manifestations and the ultrastructure of a platelet-specific microorganism isolated from a dog in Florida were studied. The agent was readily transmitted experimentally to adult dogs by intravenous inoculation with infected blood. Parasitemias and concomitant thrombocytopenias were cyclic in that both recurred within relatively constant periods of one to two weeks following experimental infections. Hemorrhage was not a manifestation of the disease even though thrombocytopenias were severe. Microorganisms were visualized by light and electron microscopy. They were observed only in platelets and were composed of single or multiple subunits (morula forms). The microorganisms were ultrastructurally very similar to those reported in Ehrlichia canis infections of dogs and Anaplasma marginale infections of cattle. Microorganisms were surrounded by single membranes which more or less conformed to the external surfaces of subunits that were surrounded by double membranes. From electron microscopic studies, it is suggested that these organisms be classified in the order Rickettsiales.

Alphaproteobacteria↗
PubMed1978

Ultrastructure of erythrocytes parasitized by Haemobartonella felis.

Experimental Haemobartonella felis infections were studied in 3 mature, intact cats by examining peripheral blood, lung, and spleen by electron microscopy. Coccoid, rod, or ring forms of the organism were found on or close to the erythrocytic membrane, and adjacent parasitized erythrocytes often were attached. Intracytoplasmic crystalloid inclusions occupying most of erythrocytic cytoplasm were seen in the 3 infected cats. The cat with the highest parasitemia had inclusions in about 10% of the erythrocytes. Less than 0.01% of the erythrocytes of a control cat contained inclusions. Parasitized erythrocytes, with and without inclusions, were seen in capillaries of the lung and spleen of infected cats. Macrophages in the lung and spleen of infected cats contained parasitized erythrocytes, either with or without inclusions. Some macrophages contained erythrocyte-free organisms in phagocytic vacuoles.

Anaplasmataceae↗
PubMed1977

Encephalomyocarditis virus infection of captive elephants.

Four African elephants at each of 2 widely separated zoologic gardens in Florida died following a fulminating illness. Tissue suspensions obtained from an elephant from each of the zoologic gardens were inoculated into newborn mice, 3- to 4-week-old mice, and buffalo green monkey and baby hamster kidney cell cultures. Encephalitis and myocarditis developed in the mice. The cell cultures were destroyed within 24 to 72 hours, and intracytoplasmic viral inclusions were observed in infected cells by electron microscopy. The viral agent was neutralized by known antiserum to encephalomyocarditis virus.

Animals↗
PubMed1977

An epizootic among knots (Calidris canutus) in Florida. II. Ultrastructure of the causative agent, a Besnoitia-like organism.

Multinucleated cysts near the luminal surface of the thoracic aortas of diseased knots (Calidris canutus) were similar to besnoitia cysts. Ultrastructurally, the cyst had four distinct layers. The central area included a vacuole that contained a sporozoan with a conoid, polar ring, micronemes, rhoptries, nucleus, mitochondria, dense bodies, a lipid-like vacuole and endoplasmic reticulum. External to the vacuole was a layer with organelles typical of vertebrate cells. The wall of the cyst was irregular in thickness and was bound by a strongly osmiophilic membrane. There was a loose, acellular area of intertwined strands between the cysts wall and layer of organelles.

Animals↗
PubMed1977

Effect of wet litter and supplemental biotin and/or whey on the production of foot pad dermatitis in broilers.

An experiment was conducted to determine whether increasing the moisture content of the litter would increase foot pad dermatitis in broilers, and to determine whether supplemental biotin or dried whey would affect this condition. Broilers grown on wet litter had significantly increased incidence of foot pad dermatitis. The addition of 3% of partially delactosed whey to the diet resulted in increasing the foot pad dermatis. The addition of biotin decreased foot pad dermatis. Examination of foot pad tissue indicated that the birds receiving the control diet were deficient in biotin.

Animals↗
PubMed1977

Experimentally induced "fatty liver syndrome" condition in laying hens.

Two experiments were conducted with aged laying hens to determine the influence of feeding 5,000 p.p.m. of iodine as potassium iodine (KI) and/or injecting 12 mg. of estradiol upon fat accumulation in the liver and serum cholesterol levels. The KI was fed for 8 days before making liver and blood determinations, and the estradiol was injected 3 days prior to making the determinations. The feeding of KI or injection of estradiol resulted in significantly increased liver weight. When the two treatments were combined a further significant increase in liver weights was obtained. The percent of fat in the liver was significantly increased by the injection of estradiol. However, the feeding of KI in the presence or absence of estradiol did not affect the percentage of fat in the liver. Neither of the treatments significantly affected the fatty acid composition of the liver fat. Feeding of KI or injection of estradiol significantly increased total serum cholesterol levels. When the two treatments were combined a further increase in serum cholesterol level was observed. Histological changes of the livers of hens treated with KI and estradiol were similar to those previously described for the "fatty liver syndrome."

Animals↗
PubMed1977

Influence of wet litter and supplemental biotin on foot pad dermatitis in turkey poults.

Two experiments were conducted with day-old Broad Breasted white turkey male poults to determine whether wet litter and supplemental biotin would influence the severity of foot pad dermatitis. Poults grown on wet litter had a significantly increased incidence of foot pad dermatitis. The addition of biotin to the corn-soy diet resulted in a decreased severity of foot pad dermatitis in poults maintained on dry litter; however, it did not influence the severity of the lesions when poults were maintained on wet litter. Histological examination of the foot pad tissue indicated that poults which received the control diet were deficient in biotin.

Animal Husbandry↗
PubMed1977

Morphologic alteration of Paranaplasma caudata following treatment of calves with oxytetracycline.

The morphologic features of Paranaplasma caudata were determined in whole blood, blood clots, and liver biopsy specimens after treating infected calves with oxytetracycline. Following staining of blood smears with new methylene blue, light microscopy showed that paranaplasma bodies in erythrocytes of treated calves were vacuolated, but tails were normal in appearance. By electron microscopic examination of parasitized erythrocytes of treated calves, paranaplasma bodies were found to be degenerated (aggregation of nucleoprotein granules in initial bodies and condensation and coalescence of initial bodies), but tails were normal. The identical degenerative changes of paranaplasma bodies and lack of alteration of tails were evident in erythrocytes in sinusoids of liver biopsy specimens from treated calves.

Anaplasmataceae↗
PubMed1976

The structlre of pili (fimbriae) of Moraxella bovis.

Cells from rough and smooth colonies of Moraxella bovis were examined by electron microscopy utilizing both shadowing and thin sectioning techniques. Pili were found on the surfaces of cells from rough but not smooth colonies. Pili had a peritrichoud distribution and appeared as delicate (6.5-8.5 nm in diameter), elongated unbranched filaments. When bacteria were sectioned pili did not contain central pores and appeared to originate from opacities on the surface of the cell wall.

Animals↗
PubMed1976

Cecal coccidiosis in poultry as affected by prior exposure to aflatoxin B1.

Young New Hampshire and broiler chickens were given feed containing 2 concentrations of aflatoxin B1 (0.2 or 2.0 ppm). The larger concentration caused severe toxicosis and death in the New Hampshire chicks, but did not cause gross signs in the broiler chicks. However, temporary stunting was seen on both New Hampshire and broiler chicks during periods of aflatoxin feeding, along with persisting decreased weight gains in the broiler chicks; the latter apparently recovered during the next 21 days of feeding the starter ration. New Hampshire and broiler chicks which were given feed containing aflatoxin B1 at concentrations of 0.2 and 2.0 ppm for 28 days followed by a 21-day "recovery period" and which were not given a coccidiostat were more susceptible to severe cecal coccidiosis and had more persisting hepatic and cecal lesions than did chicks not given aflatoxin. The coccidiostat was protective against both cecal damage and losses in checks challenge exposed at 49 days of age to 100,000 infective Eimeria tenella oocysts.

Aflatoxins↗
PubMed1976

Hypercholeresis in turkeys following the ingestion of Crotalaria spectabilis seeds.

Young female turkeys received diets containing Crotalaria spectabilis seeds for 18 weeks. Mean values for total bile flow, biliary bile acid excretion, bile acid-dependent flow and bile acid-independent flow were significantly higher in crotalaria-fed turkeys than in controls. The hypercholeresis observed in crotalaria-fed birds involved both bile acid-dependent and bile acid-independent components of bile. Crotalaria-fed turkeys developed biliary hyperplasia. Liver weights were similar in the two groups. Since increases in 14C-erythritol clearances paralleled increases in total bile flow in crotalaria-fed turkeys (14C-erythritol bile to plasma ratios were similar in both groups), it was evident that the hypercholeresis in crotalaria-fed turkeys did not involve the ductal/ductular component of bile. Little or no ductal/ductular bile flow occurred in either group since total bile flow was equal to erythritol clearance and extrapolation to zero erythritol clearance yielded zero bile flow rates in both groups. Crotalaria-fed turkeys exhibited significantly higher biliary concentrations of chlorides (associated with lower sodium , potassium and bicarbonate concentrations) than did control birds. Validation of the use of 14C-erythritol clearance for the estimation of canalicular bile flow in turkeys was provided both by substantial decreases in bile to plasma 14C-erythritol concentration ratios following the injection of avian vaso-active intestinal peptide and the failure to demonstrate chromatographically the presence of radioactive metabolites of 14C-erythritol in plasma.

Animals↗
PubMed1976

The pathology associated with single and quadruple infections of hamsters with Dipetalonema viteae.

Two groups of five hamsters were each infected subcutaneously with infective larvae of Dipetalonema viteae; one group received single infections, and the second group received quadruple infections. A third group of five hamsters served as controls. Hamsters with primary and quadruple infections had cellular infiltrates in the liver and glomerular basement membrane thickening; these lesions were more extensive in the multiple than single infections. Hyperinfected hamsters also developed subcutaneous nodules. By histologic examination, it was seen that nodules were encapsulated abscesses which had a central, necrotic core, and were confined by a fibrous connective tissue capsule. The central portion of some nodules contained nondegenerated worms. The same area of other nodules contained dead worms, while still other nodules contained calcified worms or necrotic and calcified debris.

Abscess↗