Seven goats were poisoned with daily oral doses of coyotillo fruits and killed at various times after day 12. The distribution of lesions was studied in a sensory nerve, in short and long motor nerves, and at proximal and distal sites of a long motor nerve. Fibers with Schwann-cell lesions (swollen Schwann cells or segmental demyelination) were widespread and outnumbered fibers with Wallerian degeneration in most sites. The percentage of fibers that were undergoing Wallerian degeneration was much greater in long motor nerves than in short ones and was much greater at a distal site of a long motor nerve than at a proximal site. The results were compatible with axonal injury being secondary to Schwann-cell injury and cumulative throughout the lengths of affected fibers, resulting in distal axonal degeneration.
The first histologically confirmed case of carcinoma of the horn in a bilaterally cryptorchid Malvi bull, detected during an epidemiological survey, is reported. Examinations of 78,024 bullocks and 1,468 bulls, belonging to 7 different Zebu breeds revealed horn cancer in 793 bullocks and 1 cryptorchid bull but not in a normal bull. Histologically cryptorchid testes were devoid of spermatogenesis and had hyperplasia of Leydig cells. The remnant of castrated testes had only seminiferous tubules with coagulative necrosis and were devoid of spermatogenesis and Leydig cells. The significant difference in the incidence of HC in bullocks and cows and its absence in bulls is discussed in the light of the role of hormone in the causation of HC.
A retrospective study was conducted of 1,366 cases of canine mammary neoplasms derived from 3 different populations of dogs. The mean ages for occurrence of mammary tumors varied between populations studied from the ninth to eleventh years with malignant neoplasms tending to occur later than benign. Irradiation had no effect on incidence. Poodles had the largest numbers of papillary adenomas and benign mixed tumors. Dachshunds, chihuahuas, and cocker spaniels had a large proportion of all other types. Papillary adenomas arose from the ductile or alveolar epithelium and accounted for only 5.1% of the tumors. Benign mixed rumors comprised 45.1% and consisted of an adenomatous epithelial component and proliferative fibrous connective tissue or myoepithelium which frequently had undergone metaplasia to cartilage or bone. Malignant mixed tumors accounted for 8.5%, their malignant component being most frequently epithelial. Carcinomas represented 39.7% of the tumors. More carcinomas were seen among neutered than intact females except in the closed beagle colony where carcinoma was the most frequent neoplasm in the exclusively intact female population. Among the carcinomas, an infiltrating type, usually comprised of ductile cells infiltrating an abundant fibrous stroma, was the most common. A solid type, comprised of masses of epithelial cells with scant or inapparent stroma, was next in frequency. Papillary, lobular, and squamous types of carcinomas occurred in descending order. Malignant myoepitheliomas comprised 1.1% of the tumors; fibrosarcomas, osteosarcomas, and chondrosarcomas were rare, accounting for less than 1%. Approximately 2% of the neoplasms were from males which had no predilection for a particular type of rumor.
Animals of several species, including man, are susceptible to the toxic effects of the fruits of the coyotillo shrub". The characteristics and distribution of lesions in peripheral nerves of goats poisoned experimentally with coyotillo have been reported recently4-6. The results of these light microscopic studies of teased fibers indicate that Schwann-cell injury manifested by swelling and segmental demyelination is widespread in this disease, and that axonal degeneration also occurs and is especially extensive at the ends of long nerves 4-6. This report describes the light and electron microscopic lesions in aralditeembedded samples of peripheral nerve collected from goats experimentally poisoned with coyotillo. This study formed part of a larger investigation of experimental coyotillo poisoning involving 26 goats3. Tissues from 16 of these goats (12 principals and 4 controls) were used in this study. The goats were killed at 2- or 3-day intervals between day 3 and day 23 of the experiment (except for one on day 102). The 2 goats killed on day 3 received 3 daily doses and all other goats received either 6 or 7 daily doses of coyotillo (0.04% or 0.05% of body weight per day). Details of the care and feeding, schedules of dosage and duration of survival of these goats have been described previously~~ 5. Small pieces of nerve (1 mm pieces of 1 fascicle) were removed from the mid-femoral region of the sciatic nerve of goats anesthetized with pentobarbital sodium immediately prior to euthanasia. These pieces were fixed in phosphate
Nephropathy and a syndrome of edema were produced in miniature swine by cultures of Penicillium viridicatum grown on autoclaved corn. The dried and ground cultures were mixed at a 50% concentration with a commercial pig feed. After a few days of feeding, the pigs became depressed, developed anorexia, posterior paresis, elevated blood urea nitrogen levels, proteinuria, and glycosuria. Gross lesions included subcutaneous edema, ascites, hydrothorax, hydropericardium, and mesenteric edema. Perirenal edema with accumulation of variable amounts of bloody fluid between renal capsule and parenchyma was a remarkable feature of the toxicosis. Microscopic lesions included edema of various tissues and degenerative changes in the kidney.
A description of equine cutaneous mastocytosis is given. The lesion was characterized by focal aggregates of mast cells, and by eosinophils, fibrinoid necrosis of collagen, and focal necrosis with dystrophic mineralization of necrotic debris. This is an uncommon, previously undescribed lesion in horses. The authors encountered 14 cases in a 16-year period. The etiology and nature of the lesion are undetermined. Morphologic similarities to canine cutaneous mast-cell tumors, cutaneous lesions of collagen diseases, and calcinosis circumscripta are noted and the possibility of relationships to these lesions is discussed.
The normal fine structure of the epidermis in piglets is similar to that in other mammals. Ten cases of exudative epidermitis were studied in different stages. In acute cases a crust of parakcratotic cells was evident. The cells of the stratum intermedium and the outer layers of the stratum spinosum were swollen and vacuolated. Desmosomes and tonofibrils were reduced in size and number. The intercellular spaces were enlarged and contained an opaque material. In subacute and mild cases the lesions were less pronounced. The healing process was studied in one less severe, acute case. The observations arc interpreted as indicating a primary lesion in the Stratum granulosum and possibly in adjacent cells of the stratum spinosum. No evidence of a bacterial etiology was found. The observed changes are similar to those seen in viral disease of the skin.
Verminous bronchitis and pneumonia due to Parafiaroides decorus infection is described in California sea lions ( Zalapbus californianus). Marked edema and multiple nodules occurred throughout the lungs. Histologically, both intact and degenerate lungworms occurred and the inflammatory response was pleomophic. A hyaline eosinophilic structure occurring beneath the tracheal and bronchial epithelium was morphologically similar to a structure seen in several human pulmonary diseases. Hypersensitivity may have been important in the underlying pathogenesis of This disease. Liver flukes ( Zalophotrema hepaaticum) and gastric ulcers containing nematodes ( Contraceacum osculalum) occurred in several animals.
A fatal adenoviral infection was recently recognized in suckling Arabian foals from Colorado, Kansas, Nebraska, and Wyoming. Affected foals had clinical signs of pneumonia accompanied by fever, absolute lymphopenia, and neutropenia. Characteristic lesions with typical adenoviral inclusions occurred in respiratory epithelium of all cases. Other tissues with significant changes and inclusion bodies were conjuctiva, urinary mucosa, pancreas, and salivary glands. Lymphoid follicular atrophy and hepatic degeneration were frequent but were not accompanied by inclusions.
Cutaneous histiocytomas from 4 dogs were examined by light and electron microscopy. A large (up to 10 μ in diameter) mononuclear cell with prominent filiform processes of the plasma membrane predominated. Its cytoplasm contained relatively small amounts of endoplasmic reticulum and mitochondria, only occasional lysosomes, fibrils, most obvious in the perinuclear region, and small amounts of cytoplasmic debris. Acid phosphatase was not detected. Fibroblasts and collagen formed a small part of the lesion, except at the junction with surrounding dermis, where fibers were plentiful. The morphologic features of the lesion are compatible with the suggestion that the predominant cell is of histiocytic type.
Mast-cell neoplasms may originate in skin or internal viscera of cats. Mast-cell or basophilic myelocytic leukemia may accompany disseminated mastocytosis. Ages of affected cats range from 4 to 16 years with a median age of 10 years. There is no definite predilection as to sex or breed, Neoplastic mast cells vary in degree of differentiation.
An ultimobranchial tumor of the thyroid and a phcochromocytoma occurred in a bull. The thyroid tumor contained amyloid. The occurrence of ultimobranchial tumor of the thyroid and phcochromocytoma was established in a large series of bovine necropsies and the co-existance of these tumors in the bull was highly significant; neither occurred in the cow.
