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Biomedical subjects

W E Morris

Publications and source records attributed to W E Morris.

16 recordsLinked to original sources
PubMed2004

Ovine pulmonary adenomatosis in Patagonia, Argentina.

An outbreak of pulmonary adenomatosis (OPA) occurred in sheep in Patagonia, Argentina's southernmost region. On the affected farm, nine animals died over a 6-month period with pulmonary lesions of OPA. In all cases, the histology of the lungs was characterized by proliferation of cuboideal and prismatic cells lining the alveoli. Inflammatory exudates and accumulation of alveolar macrophages were marked in most cases, but in six of the cases there was no excess fluid in the airways. The presence of the Jaagsiekte retrovirus was demonstrated in the lungs by immunocytochemistry and PCR. To the best of our knowledge, this is the first report of OPA in Patagonia.

Animals↗
PubMed2004

The pathology of peracute experimental Clostridium perfringens type D enterotoxemia in sheep.

The pathological findings in sheep with peracute experimental Clostridium perfringens type D enterotoxemia are described. Of 16 animals inoculated intraduodenally with a whole culture of this microorganism and a starch solution in the abomasum, 12 developed clinical signs including increased respiratory efforts, recumbency, paddling, bleating, convulsions, blindness, and opisthotonus. Diarrhea was not observed in any of the animals. The time lapse between the beginning of intraduodenal infusion and onset of clinical signs varied between 30 minutes and 26 hours, and the clinical course varied between 1 and 9 hours. Gross postmortem changes were observed in these 12 animals and included pulmonary edema; excess pericardial, peritoneal, or pleural fluid with or without strands of fibrin; liquid small intestinal contents; leptomeningeal edema; cerebellar coning; and subcapsular petechiae on kidneys. Histological changes consisted of severe edema of pleura and interlobular septa and around blood vessels and airways and acidophilic, homogeneous, proteinaceous perivascular edema in the brain. Five of 12 animals (42%) with clinical signs consistent with enterotoxemia lacked specific histological lesions in the brain. None of the intoxicated or control animals developed nephrosis. Glucose was detected in the urine of 3 of 6 animals that were tested for this analyte. These results stress the importance of the use of histological examination of the brain, coupled with epsilon toxin detection, for a definitive diagnosis of C. perfringens type D enterotoxemia in sheep.

Animals↗
PubMed2002

Effects of intravenous injection of Clostridium perfringens type D epsilon toxin in calves.

In cattle, a neurological lesion similar to that produced in sheep and goats by Clostridium perfringens type D enterotoxaemia has been reported. However, no causal relationship has been established between this disease and the lesion in cattle. The effects of single and multiple intravenous injections of epsilon toxin in three calves aged 6 months were studied. A further calf was inoculated intravenously with saline solution and used as a control. Epsilon toxin invariably produced neurological signs within 2-60 min of the end of the injection process. Clinical signs consisted of loss of consciousness, recumbency, convulsions, paddling, opisthotonus, hyperaesthesia and dyspnoea. Gross changes consisted of severe acute pulmonary oedema, which was particularly marked in the interlobular septa. The histological lesions consisted of intra-alveolar and interstitial oedema of the lung and variable degrees of perivascular proteinaceous oedema in the internal capsule, thalamus and cerebellar white matter. No clinical or post-mortem changes were observed in the control calf. These results show that calves are susceptible to the intravenous injection of epsilon toxin, and that they can show at least some of the histological lesions produced in sheep and goats by this toxin.

Acute Disease↗
PubMed2002

Malignant oedema associated with blood-sampling in sheep.

Malignant oedema is a fatal disease of several animal species, produced by one or more members of the Clostridium genus. We report here a case of malignant oedema in a 1-year-old Friesian sheep after a blood sample was collected from the jugular vein. Clostridium septicum and Clostridium sordellii were isolated from the lesions and also demonstrated by a fluorescent antibody test. This report stresses the need for maintaining a clean environment for animals and for strict hygienic measures during procedures that generate wounds, together with immunity acquired by proper vaccination, for prevention of malignant oedema.

Animal Husbandry↗
PubMed1993

Hemochromatosis and celiac sprue. Case report.

The patient presented with apparent hemochromatosis and celiac sprue, a unique combination not previously reported. Almost all patients with celiac sprue have an iron deficiency which is usually present very early, often antedating other manifestations of the condition.

Aged↗
PubMed1985

Teratological assessment of five oxidative hair dyes in the rat.

The oxidative dyes, 4,4'-diaminodiphenylene sulfate, N'-(2-hydroxyethyl)-4-nitro-O-phenylenediamine, N,N-dimethyl-p-phenylenediamine, 2,3-dihydroxynaphthalene, and resorcinol, were evaluated for teratogenic potential. Dyes were administered by gavage to pregnant Sprague-Dawley rats on gestation Days 6 through 15 at doses ranging from 12.5 to 500 mg/kg. No overt signs of toxicity were observed during the treatment period. A significant reduction in mean maternal weight gain was noted during the treatment period at the high dose for 4,4'-diaminodiphenylene sulfate, N'-(2-hydroxyethyl)-4-nitro-O-phenylenediamine, and 2,3-dihydroxynaphthalene. The high dose for N,N-dimethyl-p-phenylenediamine and resorcinol, which exceeded a 100-fold exaggeration of human exposure, did not produce a significant reduction in maternal weight gain. An evaluation of fetal external, visceral, and skeletal anomalies revealed no statistically significant differences between dye-treated and vehicle control groups. Administration of 100,000 units of vitamin A, the positive control, on Day 9 of gestation resulted in a significant increase in abnormal fetuses.

Animals↗
PubMed1984

A quantitative in vitro assay for the evaluation of phototoxic potential of topically applied materials.

A quantitative in vitro method for phototoxic evaluation of chemicals has been developed and validated. The assay uses Saccharomyces cerevisiae, seeded in an agar overlay on top of a plate count agar base. 8-Methoxy psoralen is used as a reference standard against which materials are measured. Activity is quantified by cytotoxicity measured as zones of inhibition. Several known phototoxins (heliotropine, lyral, phantolid, and bergamot oil) and photoallergens (6-methyl coumarin and musk ambrette) are used to validate the assay. An excellent correlation is observed between in vivo studies employing Hartley albino guinea pigs and the in vitro assay for several fragrance raw materials and other chemicals. The in vitro assay exhibits a greater sensitivity from 2-500 fold. For three fragrance oils, the in vitro assay detects low levels of photobiological activity while the in vivo assay is negative. Although the in vitro assay does not discriminate between phototoxins and photoallergens, it can be used for screening of raw materials so that reduction in animal usage can be achieved while maintaining the protection of the consumer.

Administration, Topical↗
PubMed1984

Evaluation of the teratogenic potential of the oxidative dyes 6-chloro-4-nitro-2-aminophenol and o-chloro-p-phenylenediamine.

The oxidative dyes 6-chloro-4-nitro-2-aminophenol and o-chloro-p-phenylenediamine were administered by gavage to Sprague-Dawley rats on days 6-15 of gestation at dose levels of 87.5, 175 and 350 mg 6-chloro-4-nitro-2-aminophenol/kg body weight/day and 100, 200 and 400 mg o-chloro-p-phenylenediamine/kg/day. Maternal body-weight gain was significantly reduced by the high dose of each dye and the intermediate dose of o-chloro-p-phenylenediamine. Rats given the high dose of the latter dye showed a significant increase in resorptions and a significant decrease in foetal body weights. No embryotoxic or foetotoxic effects were observed with 6-chloro-4-nitro-2-aminophenol. Evaluation of foetuses for gross, visceral and skeletal anomalies revealed no statistically significant differences between dye-treated and vehicle-control groups but showed a significant increase (to 25-91%) in the incidence of abnormal foetuses in the group exposed to vitamin A, the positive control.

Aminophenols↗
PubMed1984

Teratological assessment of the oxidative dye 4-methyl-N-ethylamino phenol sulfate.

The oxidative dye 4-methyl-N-ethylamino phenol sulfate was evaluated for teratogenic potential. The dye was administered by gavage to pregnant Sprague-Dawley rats at dose levels of 300, 600, and 1200 mg/kg on gestation days six through fifteen. No signs of toxicity were observed during the treatment period. A significant reduction in mean maternal weight gain was noted during treatment at the high dose level of 1200 mg/kg. The test material did not produce embryotoxic nor fetal toxic effects at dose levels utilized. Evaluation of fetal external, visceral, and skeletal anomalies revealed no statistically significant differences between dye treated and control groups. Oral exposure of dams to the positive control, Vitamin A, resulted in a significant increase in the number of litters with abnormal fetuses.

Animals↗
PubMed1984

Evaluation of the teratogenic potential of the oxidative dye N-phenyl-para-phenylenediamine.

The oxidative dye N-phenyl-para-phenylenediamine was evaluated for teratogenic potential. The dye was administered by gavage to pregnant Sprague-Dawley rats at dose levels of 50, 100, and 200 mg/kg on gestation days six through fifteen. No signs of toxicity were observed during the treatment period. A significant reduction in mean maternal weight gain was noted during treatment at the high dose level of 200 mg/kg. The test material did not produce embryotoxic nor fetal toxic effects at dose levels utilized. Evaluation of fetal external, visceral, and skeletal anomalies revealed no statistically significant differences between dye treated and control groups. Oral exposure of dams to the positive control, Vitamin A, resulted in a significant increase in the number of litters with fetuses having external, visceral, and skeletal anomalies.

Animals↗
PubMed1984

Evaluation of the toxicity and carcinogenicity of hair dyes in Swiss mice.

The chronic toxicologic and carcinogenic potential of two oxidative and twelve non-oxidative hair dyes has been evaluated. The dyes were skin painted up to 3 times weekly on groups of 60 male and 60 female Eppley Swiss mice. Treatments were carried out for 20 months followed by terminal sacrifice. Nine months after treatments were initiated an intermediate sacrifice of ten mice per sex per group was carried out. Body weights and survival differed little between appropriate male and female treatment and control groups. Differences between treated and control groups in absolute and relative liver and kidney weights and in hematological and urinary values were not considered to be indicative of toxicologic effects. Microscopic examinations of the skin revealed occasional hyperplasia, necrosis, ulceration and other lesions not significantly increased by dye treatment. Chronic inflammation of the skin was observed in the control and treated mice and was significantly increased by one non-oxidative dye. The predominant tumors diagnosed were liver hemangioma, lung adenoma and malignant lymphoma. There was a statistically significant increase in the incidence of malignant lymphoma in female mice in 3 treated groups when compared to control group 2, but the differences were not significant when these groups were compared to control group 1. In addition the values in these 3 groups were within the range of control values for this tumor in female mice in the Eppley colony. No other tumors occurred at significantly increased frequencies in treated mice. We conclude that toxicological and carcinogenic effects were not clearly induced by the hair dye formulations.

Animals↗