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Biomedical subjects

D W Hayden

Publications and source records attributed to D W Hayden.

At least 73 records · Page 4Linked to original sources
PubMed1981

Morphology of nasal cavity neoplasms in F344 rats after chronic feeding of p-cresidine, and intermediate of dyes and pigments.

p-Cresidine was administered in the feed at either of two concentrations (0.5 and 1.0 percent) to groups of 50 male and 50 female F344 rats for 104 weeks. Fifty animals of each sex were placed on test as controls and fed only the basic laboratory diet. All animals were observed for up to 2 weeks after discontinuation of treatment. In treated rats of both sexes, statistically significant numbers of adenomas, adenocarcinomas and squamous cell carcinomas were diagnosed in the nasal cavity. Most of the neoplasms were seen in the high dose male and female rats. 22 male rats (49%) showed poorly differentiated adenocarcinomas infiltrating the skull and brain. Only two male rats (4%) had a squamous cell carcinoma, whereas 8 female rats (17%) had squamous cell carcinomas and 14 female rats (30%) were diagnosed as having adenocarcinomas of the nasal cavity. In the 4 neoplasms studied ultrastructurally, features characteristic of adenocarcinomas were identified. Cells were arranged around central lumina lined with microvilli. The luminal edges of cells were linked together by junctional complexes. Cytoplasmic differentiation was generally poor, with ribosomes and polyribosomes being the predominant organelles. Neurogenic features were rare and difficult to identify due to unsatisfactory fixation. In one of the tumors, areas of squamous differentiation were found. The cells constituting such areas contained prominent bundles of tonofilaments which are characteristic of early squamous metaplasia.

Aniline Compounds↗
PubMed1979

Neoplasms and pigmentation of thyroid glands in F344 rats exposed to 2,4-diaminoanisole sulfate, a hair dye component.

2,4-Diaminoanisole sulfate was fed at dietary levels of 0.12% (low dose) or 0.5% (high dose) to groups of 50 male and 50 female inbred F344 rats for 78 weeks. By 107 weeks after the initial exposure, 58% of the male rats and 42% of the female rats administered the high dose had thyroid neoplasms, whereas only 7--8% of the controls developed them. Follicular cell carcinomas were the primary type of neoplasm induced. None of the controls had these tumors. The carcinomas, which were papillary, cystic, or solid, were highly invasive but did not metastasize. A brown pigment was present as granules primarily in thyroid follicular cells in all exposed rats. The amount of pigment as determined by an image-analyzing computer revealed that the cross-sectional area occupied by the pigment granules and the optical density of the granules were dose related.

Adenocarcinoma↗
PubMed1978

The goitrogenic effect of 4,4'-oxydianiline in rats and mice.

Fischer 344 rats and B6C3F1 mice were fed diets that contained 0.03, 0.06, 0.1 and 0.2% 4,4'-oxydianiline for 13 weeks. The 0.1 to 0.2% diet caused 40 to 70% mortality in female rats. Although mice ate about 3.5 times more chemical than rats, no mice died. Alopecia, dyspnea and cyanosis in rats, and lethargy in both species occurred in the 0.1 to 0.2% groups. Goiter was found in rats that died as early as the 4th to 5th week of study in the groups given the 0.06 to 0.1% diet. At the end of the study, diffuse parenchymatous goiter was seen in all rats given the 0.06% and higher concentration diets and in most mice given the 0.2% diet. In rats, the thyroids also were heavily encapsulated and had interstitial fibrosis and vascular degeneration. There was concomitant hyperplasia of pituitary basophils in both species, but an increase of cells that secrete thyrotropin was seen in rats only.

Aniline Compounds↗
PubMed1977

Urogenital blastomycosis in a dog.

Blastomycosis was diagnosed in a dog by finding the causative organism in preputial exudate and urine. Prostatic involvement was confirmed by transrectal biopsy. The dog was not treated, and, after it was euthanatized, a complete necropsy was performed. The only other sites where organisms were found were the iliac lymph nodes and the lungs. Although organisms were not found in any other part fo the genitourinary tract, both kidneys had diffuse glomerulonephritis and tubular degeneration.

Animals↗
PubMed1977

Scirrhous eosinophilic gastritis in dogs with gastric arteritis.

Three adult spayed female hunting dogs had an unusual form of chronic active gastritis. The disease lasted for months to several years. Vomiting was the most consistent clinical sign. One dog had leukocytosis with 30 percent eosinophils. The stomach of each dog was enlarged and greatly thickened. Collagen deposits, granulation tissue and eosinophils replaced most of the gastric wall. Disease of the gastric arteries ranged from fibrinoid necrosis to panarteritis. Granulation tissue obstructed the omental arteries of one dog. There also was splenic reticuloendothelial hyperplasia with fibrosis, hemorrhage and congestion, and chronic eosinophilic lymphadenitis. Although the cause of this disease was not determined, its basis probably was immunologic.

Animals↗
PubMed1976

Squamous cell carcinoma in a cat with intraocular and orbital metastases.

A well-differentiated squamous cell carcinoma metastasized to the choroid and retrobulbar tissues surrounding the optic nerve sheath in the left eye of a 15-year-old white female domestic cat. The tumor originated either in the external auditory meatus or in the middle ear and extensively infiltrated the neighboring soft tissue and bone.

Animals↗
PubMed1976

Spontaneous Frenkelia infection in a laboratory-reared rat.

Numerous, lobulated, thin-walled protozoan cysts were found in the brain and cervical spinal cord of a male Fischer rat with granulomatous encephalitis. The cysts were compartmented, 470-1000 mum in diameter, and packed with crescent-shaped organisms. Light- and electron-microscopic features of the organism were characteristic of the protozoan Frenkelia, a parasite usually found in the brain of wild rodents. Many cysts were replaced by granulomas, whereas others elicited no inflammation. Perivascular and meningeal mononuclear cell infiltrates and gliosis were common.

Animals↗
PubMed1975

Experimentally induced canine toxocariasis: laboratory examinations and pathologic changes, with emphasis on the gastrointestinal tract.

Eght dogs were orally superinfected for 1 month with 50,000 embryonated Toxocara canis ova. Results of laboratory examinations during inoculation and for 2 weeks postinoculation revealed moderate leukocytosis, marked absolute eosinophilia, hypoalbuminemia, increased concentrations of serum glutamic pyruvate transaminase, and in 2 dogs, precipitating humoral antibodies. Other changes were moderate ascites, hepatomegaly, lymphadenopathy, and focal lesions (0.5 to 3.0 mm) in liver, lung, kidney, intestine, abdominal lymph node, heart, diaphragm, and spleen. Microscopically, focal eosinophilic gastroenteritis was produced. Eosinophils and globule leukocytes were increased throughout the intestinal mucosa. Eosinophil-infiltrated and granulomatous lesions were in the same organs listed as having focal lesions, as well as in the pancreas. The importance of serum beta-globulin content as a potential diagnostic tool was emphasized, and the experimentally induced infection was compared with naturally occurring eosinophilic gastroenteritis in the dog.

Animals↗