Biomedical subjects
R B Atwell
Publications and source records attributed to R B Atwell.
Immunoperoxidase staining characteristics of Dirofilaria immitis in the dog.
The immunoperoxidase staining characteristics of Dirofilaria immitis and pulmonary tissues from infected dogs were studied by using the following sera: anti-fresh D immitis, anti-processed D immitis, anti-dog IgG, anti-dog IgG Fc, anti-dog IgM and anti-dog C3. Marked staining was observed using anti-fresh D immitis serum. Body cavity fluid and cuticle were strongly stained and hypodermis, muscle, lateral cord, testis, vas deferens, ovary, oviduct and uterus were moderately stained. Oesophagus and intestine were mildly stained. Degenerate worms were stained by all antisera. The intact and cut surfaces of microfilariae and eggs and sperm present in filariae were stained, but not their internal contents. Circulating and stored immotile microfilariae did not stain. Excreted eggs, presumed to be unfertilized and, or, degenerate, stained positively. Immunoperoxidase staining of routinely processed histological samples provides a means of assessing D immitis antigen.
Ultrastructural localization of Dirofilaria immitis antigen in canine lung tissue using the protein A-gold labelling technique.
Dirofilaria immitis antigens were demonstrated in the pulmonary tissues of dogs, with natural and experimental infection (D. immitis) in dogs using an immunostaining colloidal gold technique. Electron microscopy of thin sections treated with anti-heartworm serum revealed antigen deposition within the pulmonary microvasculatur and perivascular areas.
Cardiac changes in experimental hyperthyroidism in dogs.
Injection of triiodothyronine (T3) (1 mg/kg per day subcutaneously for 14 days) to 10 healthy dogs produced a hyperthyroid state characterised by high serum T3 concentrations, hypokalaemia, hyperactivity, loss of weight, diarrhoea and thirst. Electrocardiographic measurements showed that these dogs had an increase in heart rate of 63 +/- 11 beats/min with a significantly increased T wave amplitude without changes in R wave amplitude. Echocardiographic measurements showed no changes in fractional shortening and no evidence of ventricular hypertrophy, in contrast to reports in humans, cats and rats. However, the smooth muscle of the coronary arteries was markedly hypertrophied, which may cause a decrease in myocardial perfusion.
The humoral response in natural Dirofilaria immitis infections in dogs.
Plasma samples from dogs with infections of Dirofilaria immitis were assessed using ELISA and Western blotting techniques. These results were then assessed in relation to age and sex of the host, and to the numbers of microfilariae and adult filariae. Dogs with microfilariae tended to have lower levels of infection. In infected dogs, mean ELISA titres increased directly with the degree of infection. Dogs that were either young or mildly infected, showed a preferential antibody reactivity to antigens in the high molecular weight regions of the immunoblots. With increasing age and/or the extent of infection, an antibody response to antigens in the low molecular weight regions was apparent.
The cardiotoxicity of avocado leaves.
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Focal lymphocytic non-suppurative myocarditis and 3 degrees heart block in a 2-year-old dog.
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Cardiac failure in a koala secondary to an atrial septal defect.
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Electrocardiographic values of German shepherd dogs.
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The optimal condition for peroxidase-anti-peroxidase staining of lung tissues in canine dirofilariasis.
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Feline anaemia associated with Ehrlichia-like bodies in three domestic short-haired cats.
Three domestic short-haired cats with a history of anorexia and loss of body condition had high rectal temperatures, and a normocytic, normochromic anaemia. Two of them were also dyspnoeic, and thoracic radiographs revealed a diffuse, unstructured increase in radio-opacity involving all the lung lobes. Examination of Giemsa-stained blood smears and culture of blood monocytes revealed purplish-staining intracytoplasmic inclusions, in monocytes and lymphocytes, which occurred either singly or in aggregates. Electron micrographs of a buffy coat smear from one of the cats revealed round intracytoplasmic inclusions, with electron dense and lucid areas morphometrically similar to those found in other members of the genus Ehrlichia. An attempt to culture chlamydia from one of the cats was unsuccessful. The cats were treated successfully, one with tetracycline hydrochloride and the other two with imidocarb dipropionate.
The effect of infusions of microfilariae (L1 larvae) of Dirofilaria immitis in dogs.
Four pups were given three intravenous infusions of microfilariae over a 7-month period to determine if radiographic changes could be detected in the lungs while sensitivity to first stage microfilariae was being induced. Mild pathological changes occurred but these could not be detected on any of the radiographs. Radiographic changes described by others and 'Eosinophilic lungs' did not result from the immune response to the first stage larvae.
The role of Dirofilaria immitis antigen in the pathogenesis of pulmonary arteritis in the dog. 1. The effects of antigen infusion.
The aim of this study was to investigate the correlation between the Dirofilaria immitis antigen and morphology response of pulmonary tissue. The pulmonary arteries of D. immitis naive dogs were infused with an antigenic extract of adult female D. immitis worms. Light and electron microscopy and an assessment of vascular permeability were performed to compare arterial pathology 1 h and 5 days after antigen infusion. Thrombus formation accompanied by perivascular edema was present initially, but it was not detectable after 5 days.
Congenital lymphoedema in an Ayrshire-Friesian crossbred female calf.
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Evaluation of protein-A gold labelling with Dirofilaria immitis antigen coated nitrocellulose for the detection of anti-heartworm antibody in dogs.
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Reaction to a hair shaft in the pulmonary artery of a dog.
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Pulmonary changes associated with dead filariae (Dirofilaria immitis) and concurrent antigenic exposure in dogs.
Initially, a group of 5 dogs had their left pulmonary artery ligated 7 months prior to the insertion of filariae (Dirofilaria immitis). A second group of 3 dogs was used as controls for the various components of the experiment. Antigen (D. immitis) was injected subcutaneously on 3 occasions and necropsy was performed 5 weeks after insertion of filariae. These results were then compared to those from the control dogs. With exposure to antigen, severe pulmonary arterial and parenchymal disease was produced in association with the insertion of dead D. immitis filariae into the pulmonary artery. In the dogs receiving antigen, the arterial and peri-arterial pathology was generally more intense and at a more advanced stage of organization than in the control animals. Interstitial pneumonitis was also more prominent in the antigen-stimulated dogs. The advanced nature of the reaction was also reflected in the skin histology of the injection sites. The pathology was similar to that reported for natural dirofilariasis and it appears that most of the pathology of dirofilariasis is associated with reactions to dead filariae or filarial by-products and concurrent antigenic experience.
An evaluation of the Dirochek test for detection of Dirofilaria immitis antigen in dogs.
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