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Biomedical subjects

M A Hayes

Publications and source records attributed to M A Hayes.

At least 91 records · Page 5Linked to original sources
PubMed1980

Subacute toxicity of dietary T-2 toxin in mice: morphological and hematological effects.

Changes in hematopoietic and lymphoid tissues of young Swiss mice fed a balanced semipurified diet containing T-2 toxin (20 ppm) were examined after one, two, three, four or six weeks. During the first three weeks of exposure of T-2 toxin, lymphoid tissues, bone marrow and splenic red pulp became hypoplastic, resulting in anemia, lymphopenia and eosinopenia. Subsequently, during continued exposure to T-2 toxin, hematopoietic cells regenerated in bone marrow and splenic red pulp and became hyperplastic by six weeks. Granulopoiesis and thrombopoiesis resumed in advance of erythropoiesis. All lymphoid tissues remained atrophic throughout the six week trial. Mice exposed to T-2 toxin also developed perioral dermatitis and hyperkeratosis with ulceration of the mucosa of the esophageal region of the stomach. These results indicated that young mice were susceptible to both the irritant and the hematopoietic-suppressive toxic effects of dietary T-2 toxin. However, supression of hematopoiesis was transient and did not lead to hematopoietic failure.

Administration, Oral↗
PubMed1980

Subacute toxicity of Dietary T-2 toxin in mice: influence of protein nutrition.

The subacute toxic effects of dietary T-2 toxin (20 ppm) incorporated in semipurified diets of 8%, 12% or 16% protein, were examined in young Swiss mice after one, two, three and four weeks. Dietary T-2 toxin caused substantial reductions in growth and food consumptaion, the degrees of which were greatest in mice fed the diets of reduced protein content. T-2 toxin consistently caused similar degrees of nonregenerative anemia, lymphopenia, thymic atrophy and gastric hyperkeratosis irrespective of the dietary protein level. However, erythroid hypoplasia was temporary in mice fed T-2 toxin in the 16%-protein diet such that erythroid precursors regenerated in splenic and bone marrow and were hyperplastic after four weeks. Liver to body weight ratios of mice fed T-2 toxin in the 16%-and 12%-protein diets increased during the four week trial in comparison to control mice fed at a similar rate. These observations indicated that suppression of erythropoiesis in mice by dietary T-2 toxin was temporarty and that the interval before regeneration was prolonged by diets of reduced protein content.

Animal Feed↗
PubMed1979

Sudden death in young dogs with myocarditis caused by parvovirus.

Sudden death of pups in the 4- to 6-week age range has recently been occurring in western Canada as a result of severe, primary, nonsuppurative myocarditis. At necropsy, the prominent macroscopic lesion was pulmonary edema, and microscopically, characteristic intranuclear inclusion bodies were found within cardiac myofibers in association with myocarditis. Ultrastructurally, numerous small particles resembling parvoviruses were found within the intranuclear inclusion bodies, which were positive by direct fluorescent antibody test for canine parvovirus. Of three pups inoculated with homogenate from affected myocardium, one developed lesions resembling canine parvoviral enteritis.

Animals↗
PubMed1979

A technic for pancreatobiliary sphincteroplasty.

A technic for pancreatobiliary sphincteroplasty providing accurate approximation of tissues in a bloodless field has been presented. It is suitable and adaptable to the common duct with duodenum, as well as pancreatic duct with common duct.

Ampulla of Vater↗
PubMed1978

Acute necrotizing myelopathy from nucleus pulposus embolism in dogs with intervertebral disk degeneration.

Two dogs that suddenly developed neurologic signs indicating a severe cervical spinal cord lesion were found at necropsy to have necrotizing myelopathy secondary to nucleus pulposus embolism. One dog had embolism of arteries and veins; in the other dog, veins alone were embolized. Each dog had early degeneration and extrusion of the C6--7 disk, from which emboli originated. In one dog, arterial emboli apparently entered inflammatory vasculature in the anulus fibrosus and were forced by extrusion back through the arterial system to the radicular artery and then to the cord. Venous embolism occurred secondarily to arterial embolism. In the other dog, venous embolism resulted from direct herniation of nucleus pulposus into the longitudinal venous sinus. A comparison of the pathogenesis of embolization in each case and a survey of other reported cases suggested that necrotizing myelopathy is a complication of early degeneration of intervertebral disks in large dogs.

Animals↗
PubMed1978

Subacute toxicological evaluation of sclerotia of Sclerotinia sclerotiorum in rats.

Weanling Wistar rats of both sexes were fed diets containing 0 (control), 1% and 5% ground sclerotia of Sclerotinia sclerotiorum derived from infected rapeseed (Brassica napus). Body weight, feed consumption and clinical appearance were monitored over an 84-day period. Blood samples were collected on days 41 and 84 and necropsies performed on day 84. Weight gain and feed consumption were similar in the control and 1% groups. In the 5% group, weight gain was depressed, feed wastage was greater and at termination more than half the rats were in poor body condition with alopecia and hyperkeratosis of the tail. These effects were probably nutritional and due to unpalatability of the diet. Blood urea nitrogen and blood glucose concentrations did not vary consistently among the groups. Serum glutamic-pyruvic transaminase activity was significantly depressed (p less than 0.001) by consumption of sclerotia. This depression was dose-related and consistent on days 41 and 84. There were no significant differences (p greater than 0.05) between groups in the ratios of liver weight and kidney weight to body weight.

Alanine Transaminase↗