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Biomedical subjects

B P Stuart

Publications and source records attributed to B P Stuart.

At least 37 records · Page 2Linked to original sources
PubMed1982

Demonstration of immunity against Isospora suis in swine.

Piglets naturally exposed or experimentally infected with Isospora suis oocysts were given challenge doses of oocysts to determine the extent of development of immune resistance. Piglets in both studies shed low numbers of, or no detectable oocysts, following challenge. Administration of methylprednisolone acetate failed to induce oocyst shedding in previously infected piglets. Piglets rechallenged with I. suis following steroid injections also failed to shed significant numbers of oocysts suggesting development of immunity to reinfection.

Age Factors↗
PubMed1981

Cocklebur (Xanthium strumarium, L. var. strumarium) intoxication in swine: review and redefinition of the toxic principle.

Cocklebur (Xanthium strumarium) fed to feeder pigs was associated with acute to subacute hepatotoxicosis. Cotyledonary seedings fed at 0.75% to 3% of body weight or ground bur fed at 20% to 30% of the ration caused acute depression, convulsions, and death. Principle gross lesions were marked serofibrinous ascites, edema of the gallbladder wall, and lobular accentuation of the liver. Acute to subacute centrilobular hepatic necrosis was present microscopically. The previously reported toxic principle, hydroquinone, was not recovered from the plant or bur of X. strumarium. Authentic hydroquinone administered orally failed to produce lesions typical of cocklebur intoxication but did produce marked hyperglycemia. Carboxyatractyloside recovered from the aqueous extract of X. strumarium and authentic carboxyatractyloside, when fed to pigs, caused signs and lesions typical of cocklebur intoxication. Marked hypoglycemia and elevated serum glutamic oxaloacetic transaminase and serum isocitric dehydrogenase concentrations occurred in pigs with acute hepatic necrosis that had received either cocklebur seedlings, ground bur or carboxyatractyloside.

Animals↗
PubMed1981

Experimental aflatoxicosis in swine: morphological and clinical pathological results.

The morphological changes in livers of 30 feeder pigs fed diets containing corn contaminated by aflatoxins (0.0 microgram aflatoxins/g feed, 0.4 microgram aflatoxin/g feed, and 0.8 microgram aflatoxin/g feed) were compared with changes in hematology, liver specific serum enzymes, serum proteins, and lymphocyte stimulation indices. Histologically, the livers were classified into five groups. Pigs fed the 0.8 microgram/g diets had the most severe histological lesions of karyomegaly, bile ductule proliferation and hepatocellular degeneration plus elevated gamma-glutamyl transpeptidase, aspartate aminotransferase, and alkaline phosphatase. This group also had significantly lower total protein and albumin values compared to the control pigs. Variation in the severity of the histological lesions was seen in pigs fed 0.4 microgram/g diets as well as variation in lymphocyte indices, liver specific serum enzymes, and electrophoretic results in the affected pigs in that group.

Aflatoxins↗
PubMed1980

Isospora suis enteritis in piglets.

A species of porcine coccidia, Isospora suis, when inoculated into piglets, produced diarrhea, dehydration, weight loss and death. Gross lesions were characterized by a fibrino-necrotic membrane within the jejunum and ileum. Villous atrophy and variable erosion, often with an adhered necrotic membrane, were seen microscopically. Asexual and sexual stages of I. suis were seen within the intestinal epithelium and oocysts were recovered from the feces. The severity of clinical disease and lesions were dose-related.

Animals↗
PubMed1980

Endogenous development of the swine coccidium, Isospora suis Biester 1934.

The endogenous development of Isospora suis Biester 1934 is described in piglets inoculated with 150,000 or 200,000 sporulated oocysts. Endogenous stages developed within villous epithelial cells throughout the small intestine. Two distinct types of meronts were seen in tissue sections. Type I meronts, which were seen at 3 days postinoculation, were binucleate, elongate, and 10.5 by 4.7 micron. They produced two to 14 Type I merozoites per parasitophorous vacuole. Type I merozoites were 10.0 by 3.6 micron. They produced two to 14 Type I merozoites per parasitophorous vacuole. Type I merozoites were 10.0 by 3.6 micron. Type II meronts, which were seen at 4 days postinoculation, were elongate and contained three to 12 nuclei. Type II meronts were 11.4 by 5.3 micron, and one to four were found per parasitophorous vacuole. Type II merozoites were 6.3 by 2.1 micron, and three to 16 were found per parasitophorous vacuole. The peak of asexual development occurred 4 days postinoculation. Fully developed microgamonts, macrogamonts, and oocysts were seen 5 days postinoculation. The prepatent period was 5 days, and the patent period was 5 to 8 days. No extraintestinal stages were seen.

Animals↗
PubMed1978

Spontaneous renal disease in beaver in Louisiana.

Interstitial nephritis was present in 13 of 25 adult beavers (Castor canadensis). Results of serum chemistry, serotyping, and culture for leptospires were compared with the extent of renal lesions. Although the pathogenesis of the nephritis was not determined, the survey provided baseline information on spontaneous renal disease in beavers.

Animals↗
PubMed1977

Spontaneous renal disease in Louisiana armadillos (Dasypus novemcinctus).

Renal lesions were present in 34 (68%) of 50 armadillos (Dasypus novemcinctus) collected for a survey of the prevalence of leptospires in Louisiana wildlife. The renal lesions were not associated with elevations in the renal function tests of blood urea nitrogen or serum creatinine or with consistent serologic or cultural evidence of leptospires.

Animals↗
PubMed1977

Renal lesions in striped skunks (Mephitis mephitis) from Louisiana.

Renal tissue from 100 striped skunks (Mephitis mephitis) examined microscopically showed evidence of inflammation in 74% of the kidneys. Azotemia was present in 20% of the skunks that had severe renal lesions. The cause of inflammation is unknown, but leptospires were cultured from kidneys or urine of 55% of these skunks.

Animals↗
PubMed1975

Perirenal edema and toxic nephrosis in cattle, associated with ingestion of pigweed.

Twenty-two young cows died or were euthanatized after intoxication associated with ingestion of redroot pigweed (Amaranthus retroflexus) growing in marginal grass pasture. After several days of weakness and posterior incoordination, the cattle became recumbent but remained alert. Pertinent clinical laboratory findings included increased blood urea nitrogen content and marked proteinuria. At necropsy, perirenal edema and toxic tubular neprosis were seen.

Animals↗
PubMed1975

Glomerular lesions associated with proteinuria in clinically healthy dogs.

Spontaneous proteinuria in otherwise clinically normal adult Beagles 4-6 years old was studied for 2 years. Eighteen dogs, representing a population of 218 Beagles, were placed into three groups: group I, nonproteinuric; group II, intermittently proteinuric; group III, persistently proteinuric. The groups were alike on the basis of laboratory tests, except urinary protein loss. Proteinuria was persistent in most affected dogs but not progressive during the 2 years. The loss of proteins with high molecular weight, including alpha-, beta-, and gamma-globulins, suggested the proteinuria was of glomerular origin. There were glomerular lesions but no other significant change in the kidneys and urogenital system. Lesions were generalized and characterized by prominent, local or diffuse mesangial proliferation and by thickening, wrinkling, and splitting of the glomerular basement membrane. The subendothelial space was often widened and contained electron-dense deposits. Similar electron-dense deposits, as well as lipid and mineral, were in the mesangium. Alterations in visceral epithelial cells and endothelium were prominent. Periglomerular sclerosis was present but tended not to correlate with the severity of mesangial change in any given renal corpuscle. The severity of both mesangial and periglomerular changes increased with increasing proteinuria. Immunofluoescence studies demonstrated granular discontinuous localization of IgG and betaIC-globulins in the glomerular capillaries and mesangium. Similar localization was seen but to a lesser extent in nonproteinuric dogs. The glomerular lesions seen in these clinically healthy, proteinuric dogs are similar to those described in various canind diseases associated with terminal renal failure.

Animals↗
PubMedDate not supplied

A combined reproduction, neonatal development, and neurotoxicity study with 1,6-hexamethylene diisocyanate (HDI) in the rat.

1,6-Hexamethylene diisocyanate (HDI), a chemical widely used in commercial polyurethane products, was evaluated in a combined reproductive/developmental/neurotoxicity study. Sprague-Dawley rats (n = 120; 15 per sex/dose group) were administered via whole-body inhalation exposure either 0, 0.005, 0.05, or 0.3 ppm HDI for 6 h/day during a 14-day premating phase, up to a 14-day mating phase, and a 21-day gestation phase. The dams and their litters were maintained for a 4-day lactation phase during which exposure to HDI was discontinued. Neurobehavioral testing (automated measures of activity and a functional observational battery) was conducted before exposure, after the premating phase, and before termination. Body weight and clinical observations were recorded throughout the study. Terminal examinations included a gross necropsy, hematology, and clinical chemistry. Tissues retained for microscopic examination included the reproductive organs, neural tissues, nasal turbinates (multiple sections), trachea, larynx, and lung. The animals were also evaluated for effects on mating, fertility, gestation length, litter size, pup sex ratio, and pup viability. In the 0.300 ppm dose group a statistically significant decrease in body weight was observed in the females on day 4 of the study. Also observed at this dose level, in both males and females, were microscopic alterations in the nasal cavity, primarily epithelial hyperplasia, squamous metaplasia, chronic-active inflammation, and more seriously, degeneration of the olfactory epithelium. Similar microscopic effects were also observed, albeit to a lesser extent, in the males and females of the 0.05 ppm dose level. No histopathologic effects were observed in the 0.005 ppm dose level. No effects on any reproductive or neurotoxicologic parameters, hematology, clinical chemistry, or any effects on pup growth and development were observed at any exposure level.

Administration, Inhalation↗
PubMedDate not supplied

The conduct of a two-generation reproductive toxicity study via dermal exposure in the Sprague-Dawley rat--a case study with KBR 3023 (a prospective insect repellent).

KBR 3023, 1-(1-methyl-propoxycarbonyl)-2-(2-hydroxyethyl)-piperidine, a prospective insect repellent being developed by the Bayer Corporation, was evaluated for reproductive toxicity in the Sprague-Dawley rat. As the intended human use of the test compound is topical, the test system was also exposed to the compound via the dermal route. Specifically, the adult rats (P generation) were fitted with Elizabethan collars, to reduce the likelihood of oral ingestion, and dermally administered either 0, 50, 100, or 200 mg KBR 3023/kg body weight throughout the study (5 d/week) beginning at the onset of the 10-week premating period and continuing through the mating, gestation, and lactation phases. Clinical signs and changes in body weight and food consumption were assessed throughout the study. All adults and neonates underwent a gross necropsy examination. Tissues retained for microscopic examination from all adult animals included the kidney, liver, pituitary, reproductive organs, and samples of skin from the shaved dose site. In addition to the parameters noted above, the animals were evaluated for the effect of the test compound on estrous cycling, mating, fertility, gestation length, litter size, pup sex ratio, and pup viability. There were no test compound-related clinical signs or effects on body weight or food consumption observed in either the adults or the pups during any phase of the study. There were no compound-related effects on any reproductive or litter parameters. Dermal findings at the dose site (acanthosis and hyperkeratosis) were noted in both generations. Other than the dermal findings, no compound-related necropsy findings were seen in either the adults or the pups. No compound-related histopathologic findings were noted in the reproductive tissues of either the males or females. Based on these results, KBR 3023, administered as described in this study at dose levels as high as 200 mg/kg body weight (the physical limit of dermal application for this compound), did not demonstrate any reproductive toxicity.

Administration, Topical↗