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Biomedical subjects

R I Miller

Publications and source records attributed to R I Miller.

At least 55 records · Page 3Linked to original sources
PubMed1984

The comparative pathology of equine cutaneous phycomycosis.

Pythiosis (204 cases, 77%), basidiobolomycosis (48 cases, 18%), and conidiobolomycosis (14 cases, 5%) were diagnosed morphologically from 266 horses with phycomycosis. All lesions were cutaneous ulcerative granulomas and three horses with pythiosis had metastatic lesions in regional lymph nodes. Lesions of pythiosis contained characteristic yellow, coral-like coagula and had a fibrotic surface containing sinus tract openings. Basidiobolomycosis was characterized by infrequent small yellow coagula and a yellow line of fungal invasion beneath an edematous surface. Lesions of conidiobolomycosis had numerous small coagula and a nasal location. There were minor differences in inflammatory cell populations within the granulomatous lesions. Most differences were associated with coagula size and fungal morphology. Coagula were composed of collagen, fibrin, cellular debris, degranulated and whole eosinophils and hyphae. Histochemistry revealed no major differences among the three diseases. Pythium sp hyphae were 2.6 to 6.4 micrometers in diameter, had thick walls, and occasionally were septate. Basidiobolus haptosporus hyphae were 5.1 to 20.5 micrometers in diameter, had thin walls, and commonly were septate. Conidiobolus coronatus hyphae were 5.1 to 12.8 micrometers in diameter, had thin walls, and commonly were septate. A perihyphal eosinophilic cuff ( Splendore - Hoeppli phenomenon) with a radius of up to 20 micrometers was associated with the latter two fungi. Ultrastructurally, Pythium sp was composed of a thick, single density cell wall while B. haptosporus and C. coronatus had thin, double-layered cell walls.

Animals↗
PubMed1983

Complications associated with immunotherapy of equine phycomycosis.

Five horses with pythiosis of the limbs were treated unsuccessfully by surgery or topical application of amphotericin B, or both. Follow-up immunotherapy resulted in 1 horse responding favorably. Three horses were cured of the fungal infection but developed osteitis or deep-seated laminitis, which necessitated their destruction. The remaining horse, which had severe anemia, died before the course of vaccination was completed.

Animals↗
PubMed1983

Investigations into the biology of three 'phycomycotic' agents pathogenic for horses in Australia.

Although 'phycomycosis' is a common disease of horses in northern Australia little is known about the causative fungi. In this paper the laboratory methods for diagnosis are described. These revealed 38 cases caused by Pythium sp. (Hyphomyces destruens), 6 cases caused by Basidiobolus haptosporus and 2 caused by Conidiobolus coronatus. Laboratory studies on the chemotatic behaviour of zoospores of Pythium sp. showed that they were strongly attracted to both animal hairs and plant tissue. Because of this behaviour a simple baiting method using human hair was used to trap the fungus from water samples taken from different locations near Townsville, Queensland. B. haptosporus was isolated by indirect culture from the faeces of 5 bearded dragon lizards (Amphibolurus barbatus) captured near a small creek near Brisbane. By combining previously published information with data obtained in the present study, ecological life-cycles for Pythium sp., B. haptosporus and C. coronatus are proposed. They include mechanisms whereby horses may become infected.

Animals↗
PubMed1983

Experimental pythiosis in rabbits.

Rabbits were injected by subcutaneous, intraperitoneal and intravenous routes with suspensions of motile zoospores of a Pythium sp. isolated from a subcutaneous lesion of a horse in north Queensland. Some animals injected by the subcutaneous route were also treated by cortisone injections. Animals in each group were found to be highly susceptible to infection. Injection by the subcutaneous route resulted in progressive granulomatous eosinophilic abscesses in all normal and cortisone-treated animals. Preferential hepatic invasion developing into severe necrotizing hepatitis was the most common lesion in the intraperitoneally injected group. In intravenously injected animals severe embolic mycotic nephritis was the principal lesion. A significant progressive leukocytosis with moderate neutrophilia and mild monocytosis was observed in the subcutaneously and intraperitoneally injected immune competent animals. Cortisone-treated subcutaneously injected animals did not develop a leukocytosis. Many of the cortisone-treated control animals showed increased susceptibility to bacterial infections while the cortisone-treated fungal-injected animals did not.

Animals↗
PubMed1983

Evaluation trends.

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Evaluation Studies as Topic↗
PubMed1982

Clinical observations on equine phycomycosis.

During a clinical study of equine phycomycosis in tropical northern Australia 3 specific forms of phycomycosis were identified. Of 266 cases diagnosed in 5 different laboratories, hyphomycosis caused by Hyphomyces destruens was responsible for 76.7%, basidiobolomycosis caused by Basidiobolus haptosporus for 18.0%, and entomophthoramycosis caused by Conidiobolus coronatus for 5.3%. Most cases of hyphomycosis were observed between March and July, that is after the monsoonal wet summer, but were calculated from clinical histories to originate in the wet season between November and May. Basidiobolomycosis and entomophthoramycosis occurred regularly during the year and no seasonal incidence could be determined. All of these conditions occurred in horses in similar tropical regions of Queensland and the Northern Territory. No breed, sex or age predisposition was found but significant differences between the 3 fungal diseases in site of infection and appearance and size of the lesion were observed. Hyphomycosis was seen as an ulcerative granuloma containing characteristic coral-like kunkers. Lesions were most commonly found on the legs and ventral parts of the chest and abdomen, areas where contact with swamp water was apparent. Basidiobolomycosis was clinically similar to hyphomycosis but was mostly found on the lateral parts of the trunk and face where contact with contaminated soil might be expected. All lesions of entomophthoramycosis were located in the nasal region thus suggesting infection by inhalation.

Animals↗
PubMed1982

Immunological studies on equine phycomycosis.

One in vivo and 2 in vitro tests were developed to study immunological aspects of phycomycosis in clinically infected, recovered and normal in-contact horses. Serum from all infected horses gave positive readings in an agar-gel double diffusion test; serum from normal and recovered horses did not react. A complement fixation test detected antibody against Hyphomyces destruens in 82% clinical cases at an average titre of 20. Serum from recovered and in-contact horses reacted sporadically at positive titre. An intradermal hypersensitivity test (Heaf test) was used to detect evidence of cellular immunity to H. destruens. Positive tests were observed in 64% of clinically infected horses, 100% of recovered animals and 31% of normal in-contact horses. Negative tests in the clinically infected group were thought to be due either anergy in chronic cases or no stimulation in very acute cases. It was concluded that many horses showed evidence of past contact with H. destruens and had acquired resistance to infection.

Animals↗
PubMed1982

A survey of granulomatous and neoplastic diseases of equine skin in north Queensland.

A survey of granulomatous and neoplastic diseases of the skin of horses of tropical north Queensland was carried out during the period 1970-1980. Of 338 horses affected, 46.4% suffered from equine fibrosarcoma (sarcoid), 30.2% from phycomycosis, 7.4% from squamous cell carcinoma, 6.8% from other tumours, 4.7% from cutaneous habronemiasis and 4.4% from exuberant granulation tissue. Most specimens were submitted during the first half of the year after the wet monsoonal season and significantly more diseases originated during the first quarter. There was minor variations with breed, age and sex susceptibility between each disease group. Most lesions were found on the legs and head although other parts of the body were also affected. The size and anatomical distribution of lesions varied with each disease. When the results of this survey were compared with reports from southern Queensland as well as from Florida and the United Kingdom, major differences between localities were observed. Some reasons for the differences are discussed.

Animals↗
PubMed1981

Treatment of equine phycomycosis by immunotherapy and surgery.

Treatment of equine phycomycosis with a vaccine derived from ultrasonicated hyphae of Hyphomyces destruens was attempted in 30 cases of clinical hyphomycosis, 10 cases of hyphomycosis following unsuccessful surgery and 5 cases of basidiobolomycosis. Approximately 53% of animals with clinical hyphomycosis were cured after vaccination, while a further 33% clinically improved. All horses with hyphomycosis treated within 2 weeks of unsuccessful surgery were cured. There was no response to vaccination with a Hyphomyces preparation in horses with basidiobolomyucosis, while surgery alone resulted in a cure of approximately 69%. Animals tolerated the vaccination procedures well. In all cases there was a moderate to severe reaction at the site of subcutaneous injection which subsided within 96 hours. In approximately 30% of injections a sterile abscess formed at the site but responded promptly to treatment. Response to vaccination at the site of the lesion was observed within 7 to 10 days of first injection. There was progressive reduction of pruritus, drying of the surface of the lesion, expulsion of kunkers, fibrosis of the granuloma, and eventually complete epithelialisation.

Animals↗