bluuebunny/crossref_metadata_2025 huggingface dataset:
Hemangiomas of a Bovine Fetus with a Chorioangioma of the Placenta
Authors: Kirkbride C. A. , Bicknell E. J. , Robl M. G.
Published: March 2010

A bovine fetus aborted at approximately 8 months gestation had a pedunculated mass 3.5 × 2.5 × 2 cm attached to the skin of the volar surface of the left anterior limb proximal to the carpus. Another pedunculated mass 1.5 × 1 × 1 cm was on the right ventrolateral surface of the tongue at the level of the first molar tooth. A tumor 13 × 10 × 8 cm was between the chorionic and allantoic epithelial layers of the placenta. Each of these tumors was made up of loose fibrous tissue containing many capillaries. They were considered to be hemangiomas. An analogy possibly exists between this condition and fetal vascular anomalies, which frequently accompany chorioangiomas in humans.
Partielle Cerebellarhernie beim Löwen (Panthera leo L.) Pathologische Befunde am Kleinhirn und am Schädelskelett
Authors: Tuch K. , Pohlenz J.
Published: March 2010

Postmortem examination of two 15- and 17-months-old lions with central nervous signs of ataxia and opisthotonus showed bone lesions and displacement of the cerebellum into the foramen magnum occipitalis. The bone lesions were histologically characterised by apposition of osseous and osteoid tissue. The lesions in the cerebellum consisted of hemorrhagic infarction, reduction of granular and Purkinje cells, and demyelinisation; in the spinal cord hydromyelia and demyclination were seen. The possible role of vitamin A deficiency is discussed.
Rhabdomyosarcoma of the Urinary Bladder in Dogs
Authors: Kelly D. F.
Published: March 2010

Rhabdomyosarcoma of the urinary bladder in four dogs is described. The tumours were large fungating masses that protruded from the wall into the lumen of the bladder. There was local invasion of the bladder, but metastases were not found at necropsy. One dog was 1 year old when first seen, one was 14 months, and two were 18 months old. Three of the four dogs were St. Bernards. Three other published cases of rhabdomyosarcoma of the canine urinary bladder are reviewed, and features of this tumour are compared with those of botryoid sarcoma in man.
Lesions Produced by a New Lungworm in Beagle Dogs
Authors: Hirth R. S. , Hottendorf G. H.
Published: March 2010

An enzootic lungworm infection caused by a nematode not previously found in the dog, and probably representing a new species in the Filaroides-Metathelazia group, was found during postmortem examination of Beagle dogs purchased from a commercial breeder. Abnormal respiratory signs were not present, and clinicopathologic tests did not aid in the antemortem detection of infected dogs. Lungworms were present only in alveoli and terminal and respiratory bronchioles. In the majority of dogs there was a focal, granulomatous reaction directed against the adult lungworm, but a remarkably broad spectrum of other pulmonary changes was also seen, including some that mimic drug-induced and neoplastic lesions. Preliminary evidence suggests this lungworm may be present in a number of kennels that breed Beagles for use in research.
Feline Mammary Hypertrophy
Authors: Allen H. L.
Published: March 2010

A retrospective study of some 500 biopsies from female cats showed 12 examples of a benign flbroglandular proliferation of the mammary gland. This condition has not been reported in the literature. The lesion resembles pericanalicular fibroadenoma of women and may involve one or more mammary glands in young, intact queens. No statistically significant breed incidence was found. The growths regress with ovariectomy, which suggests hormonal pathogenesis (hyperprogesteronism).
Bordetella bronchiseptica Infections in Germ-Free Swine: An Experimental Pneumonia
Authors: Meyer R. C. , Beamer P. D.
Published: March 2010

Five-day-old germ-free piglets were challenged intranasally with Bordetella bronchiseptica. Infection with this agent consistently resulted in an acute bronchopneumonia characterized by broncholitis, hemorrhage, edema, necrosis, and epithelialization. In the absence of predisposing factors such as the additive or synergistic activity of a virus or mycoplasma, it was concluded that strains of B. bronchiseptica can initiate respiratory tract infections and in susceptible young swine can be a primary cause of pneumonia.
An Unidentified Sporozoan Encephalomyelitis in Sheep
Authors: Hartley W. J. , Blakemore W. F.
Published: March 2010

Severe encephalomyelitis with myelomalacia in two young sheep was associated with an unidentified sporozoan parasite that was passing through a schizogonic cycle in astrocytes. Mature merozoites were 5-7 μm in length, had a conoid, subpellicular micro-tubules, paired organelles and many micronemes. Their morphology is compared with that of Toxoplasma and other related sporozoans. The apparent absence of gametogony suggests that the schizogonic cycle in the central nervous system could be an aberrant dead-end cycle.
Ultrastructural Studies of Spleens, Brains, and Brain Cell Cultures of Mice with Scrapie
Authors: Lamar C. H. , Gustafson D. P. , Krasovich Margaret , Hinsman E. J.
Published: March 2010

Mouse brains, cell cultures of mouse brains, and spleens from mice with scrapie were examined by electron microscopy. Brains and spleens of 10 scrapie-inoculated and control mice were studied. Seven brain-cell cultures, four of which were from mice inoculated intracerebrally or subcutaneously with scrapie, were examined. Status spongiosus and vacuolated neurons were found in the brains. Structures 35 nm in diameter were seen in the brains of mice inoculated intracerebrally. They were not evident in cell cultures, although a vacuolated structure was found in one such culture. No significant changes were found in the spleens.
The Cartilage Analogue of Fibromatosis (Juvenile Aponeurotic Fibroma) in Dogs
Authors: Liu S.-K. , Dorfman H. D.
Published: March 2010

A firm, poorly circumscribed soft tissue tumor occurred in the frontal and occipital or temporal musculature of four mature dogs aged 7-12 years. Radiographically, many nodular or stippled densities were scattered throughout the soft tissue mass, and the cranial bones were eroded. The tumor was characterized by nodular aggregations of proliferating chondrocytes surrounded by calcified matrix or chondroid ground substance. The intervening stroma was fibrous. These infiltrating fibrous lesions with calcified metaplastic cartilage have not been reported previously in the dog and are similar to calcifying aponeurotic fibroma in man.
Toxoplasma-like Encephalomyelitis in the Horse
Authors: Beech Jill , Dodd D. C.
Published: March 2010

Eight horses with progressive neurologic signs had encephalomyelitis associated with toxoplasma-like protozoan bodies. There were scattered hemorrhagic, malacic lesions in white and grey matter in the brain and spinal cord. Microscopically there was malacia, mononuclear cell infiltration, especially perivascularly, gliosis, and various degrees of necrosis and hemorrhage. Other tissues were normal, except for the lung of one horse that had focal bronchopneumonia. The cerebrospinal fluid did not contain measurable amounts of IgM, IgG, or IgA. Serum from one horse was negative at 1:64 by the hemagglutination-inhibition test for toxoplasma antibodies.
Adenocarcinoma of the Olfactory Gland in the Dog
Authors: Zaki F. A. , Liu S.-K.
Published: March 2010

Adenocarcinomas of the olfactory glands were diagnosed in five dogs. The tumors had invaded the adjacent olfactory and prefrontal areas of the cerebral hemispheres. The masses consisted of large sheets of neoplastic epithelial cells separated by connective tissue stroma. In some areas there were hemorrhage and necrosis. The anterior parts of the cerebral hemispheres had been destroyed by the invasive neoplastic cells, and the white matter in the areas was very edematous. Review of the medical and veterinary literature yielded no description of tumors originating in the olfactory glands.
Anterior Capsular Opacities (Spurious Cataracts) in Beagle Dogs
Authors: Hirth R. S. , Greenstein E. T. , Peer R. L.
Published: March 2010

Small, punctate, anterior capsular opacities were detected in 24 of 1314 Beagle dogs. In the area adjacent to the punctate lesion, the lens often had a ground-glass appearance. The opacities were always centrally located and produced no obvious clinical loss of vision. They were composed primarily of fibrous tissue and nuclei, and sometimes there was also brown pigment. The lesions were intimately associated with the zonular lamella of the anterior lens capsule but did not appear to affect the cuticular part of the capsule nor to be a proliferation of the capsular epithelium. The opacities were considered to represent remnants of the embryonic, fibrovascular pupillary membrane.
Congenital Ameloblastoma in a Calf
Authors: Cheema A. H. , Shanin H.
Published: March 2010

A large mass was found in the incisor region of the mandible in an 8-hour-old female calf. It had papillary projections and infiltrating anastomosing cords and islands of oral epithelium with a peripheral row of columnar cells. There was excessive keratinization on the surface as well as in the center of cords. Histologically it resembled epidermoid carcinoma and epulis. This is probably the second report of a congenital ameloblastoma.
Lesions of Spontaneous Subclinical Disease in Beagle Dogs
Authors: Hottendorf G. H. , Hirth R. S.
Published: March 2010

Postmortem examination of 1000 commercially bred Beagle dogs used in 39 drug-safety evaluations showed a spectrum of concurrent lesions of spontaneous, subclinical disease that was used to develop a profile of lesions. This profile included the gross observations and the histopathologic findings in at least 36 different tissues from 647 of these dogs. The incidence, sex distribution, and etiologic classification of 77 different spontaneous lesions and the occurrence of four species of parasites are indicated. The profile provides a means of differentiating concurrent, spontaneous lesions from those induced by experimental procedures in ‘normal’ Beagle dogs.
Toxicity of Nerium oleander in the Monkey (Cebus apella)
Authors: Schwartz W. L. , Bay W. W. , Dollahite J. W. , Storts R. W. , Russell L. H.
Published: March 2010

The toxic effects of Nerium oleander were evaluated in capuchin monkeys ( Cebus apella) by examination of clinical signs, hematologic and serum chemical values, and gross and microscopic lesions. Dried and ground oleander leaves were given at intervals of 48 h in doses of 30, 7.5, and 3 mg/kg body weight. The cumulative lethal dose ranged from 30 to 60 mg/kg body weight in monkeys that were given doses of 30 and 7.5 mg/kg body weight. Monkeys that received doses of 3 mg/kg body weight (total cumulative dose: 60 mg/kg) survived. Clinical signs were vomiting, salivation, polyuria, bradycardia, vaginal hemorrhage, abortion, anorexia, constipation, loss of body weight, narcosis, restlessness, weakness, and shallow and rapid respirations. Changes in blood values were leukocytosis; neutrophilia; increased potassium, glutamic-oxalacetic transaminase, glutamic-pyruvic transaminase, blood urea nitrogen and α-globulins; reticulo-cytopenia; and decreased calcium, glucose, total serum protein, albumin, γ-globulin levels and albumin-globulin ratios. Hemorrhages, degeneration, or necrosis, or all of these, were observed in the heart, gastrointestinal tract, skeletal muscles, ovaries, adrenal glands, liver, kidneys, and pancreas. The organ weights of the pancreas were significantly reduced. Adrenal weights were significantly increased in monkeys that received the highest dose level.
Spontaneous Glomerulonephritis in Dogs: I. Classification and Immunopathology
Authors: Müller-Peddinghaus R. , Trautwein G.
Published: March 2010

A morphological study of kidneys of 101 dogs with and without clinical signs of renal disease was done. In 90% of the dogs there was morphologic evidence of glomerulopathy. Types of glomerulonephritis were: membranous, 26 cases (with spikes, six cases; without spikes, 20 cases); membranoproliferative, 30 cases (with mesangial proliferation, nine cases; with mesangial sclerosis, 21 cases); mesangial-proliferative, 16 cases; and mesangial-sclerosing, 19 cases. There was no linear immunofluorescence indicative of autoantibodies to the glomerular basement membrane. Membranous glomerulonephritis with spikes was associated with coarse subepithelial deposits of IgG and C3. Membranous glomerulonephritis without spikes often had a linear fluorescence pattern of C3. In membranoproliferative glomerulonephritis, there were subendothelial deposits of IgG and C3, and frequently C3 deposits were within the mesangium. Mesangial deposits of C3 were frequently found in kidneys with mesangial-proliferative and mesangial-sclerosing glomerulonephritis and glomeruli that histologically appeared normal.
Two Renal Tumors in Cottontail Rabbits (Sylvilagus floridanus)
Authors: Carlton W. W. , Dietz J. M.
Published: March 2010

Renal tumors were found in two cottontail rabbits (Sylvilagus floridanus) about 1 year old. One tumor was intimately associated with the kidney and consisted of isolated ductular and tubular structures within an abundant connective tissue stroma and was diagnosed as a hamartoma of urogenital origin. The second was composed of epithelial cells arranged as alveolar structures with papillary projections, epithelium that was less differentiated into tubules and ducts, and neoplastic epithelial cells in solid sheets. The diagnosis of renal adenocarcinoma was based on the histologic features as metastasis had not occurred.
The Pathogenesis of Porcine Rectal Stricture: II. Experimental Salmonellosis and Ischemic Proctitis
Authors: Wilcock B. P. , Olander H. J.
Published: March 2010

Experimentally induced oral Salmonella typhimurium infection in pigs resulted in a severe, prolonged enterocolitis with ulcerative proctitis a constant feature. Healed lesions were annular cicatricial ulcers in the part of the rectum affected with rectal strictures. Strictures indistinguishable from the naturally occurring lesion were produced by injecting chlorpromazine into the cranial hemorrhoidal artery of three pigs. Dye injected into the cranial hemorrhoidal artery perfused the entire rectum in normal pigs, but in pigs with either rectal stricture or salmonella proctitis the dye halted at the cranial margin of the transverse mucosal defect. The predilection of rectal stricture and its proposed precursor, salmonella ulcerative proctitis, for the middle third of the rectum was attributed to a normally precarious arterial supply which renders the rectum unusually susceptible to ischemic injury and decreases its reparative capacity.
Pathology of Subacute Bitterweed (Hymenoxys Odorata) Poisoning In Sheep
Authors: Witzel D. A. , Jones L. P. , Ivie G. W.
Published: March 2010

Subacute bitterweed ( Hymenoxys odorata) poisoning was produced in sheep by force feeding them ground plant material (1 gm/kg/day) for 15 days. Five sheep died, and two became moribund and were killed at the end of the experiment. The forestomach and abomasum were severely congested and occasionally eroded on the mucosal surface. There was an accumulation of edematous fluids along the rumino-reticular folds and ruminal sulci. Gaseous and fluid distension of the forestomachs, abomasum and cecum was a consistent finding. The gall bladder was greatly distended and occasionally the mucosa was sprinkled with petechiae. The most common finding was severe glomerulonephrosis characterized by proteinaceous casts, swollen and degenerated glomerular tufts and degeneration and necrosis in the inner renal cortex and outer medulla. Mild to moderate toxic hepatosis, characterized by vacuolar degeneration of hepatocytes primarily around the central vein, was consistent.
Feline Panleukopenia I. Pathogenesis in Germfree and Specific Pathogen-Free Cats
Authors: Carlson J. H. , Scott F. W. , Duncan J. R.
Published: March 2010

Germfree and specific pathogen-free cats were inoculated with panleukopenia virus. Total leucocyte counts decreased significantly in both germfree and specific pathogen-free cats. Clinical illness was not seen in any germfree cat. Specific pathogen-free cats had anorexia and slight diarrhea 5-6 days after inoculation. None of the cats died. Both germfree and specific pathogen-free cats had thymic involution. No other gross lesions were seen. Tissues for histological virus isolation and immunofluorescence studies were taken daily from days 2 through 6 after inoculation. Virus-infected cells and lesions of panleukopenia were seen in the small intestine of both germfree and specific pathogen-free cats. The incidence of virus-infected cells and lesions was greater in specific pathogen-free cats than in germfree cats.
Hypothalamic Hamartoma in a Dog
Authors: Cook R. W.
Published: March 2010

A 10-month-old female, Wire-haired Pointing Griffon dog had a hamartoma of the hypothalamus. Episodes of sudden flaccid collapse had increased in frequency and duration for 7 months. Cerebrospinal fluid pressure was normal. A flat, pedunculated mass, 2.5×3.0×0.9 cm, covered the brain stem between the pituitary gland and pons. Its 1.2-cm-diameter connection to the hypothalamus obliterated the mammillary bodies and extended to the tuber cinereum, distorting the hypothalamus and displacing the third ventricle which also divided the rostral part of the mass. The tissue of the hamartoma resembled gray matter with bullous cytoplasmic vacuolation of many neurons, spongiform change, gemistocytosis and microscopic foci of calcification.
Chronic Dermatosis and Cutaneous Squamous Cell Carcinoma in the Beagle Dog
Authors: Hargis A. M. , Thomassen R. W. , Phemister R. D.
Published: March 2010

Chronic dermatosis developed in sparsely-haired, lightly pigmented, ventral body skin in 397 of 1 680 beagle dogs by the time the dogs were 5 1/2 years old. Twenty-six of 55 other beagles had developed such lesions by 12 years of age. Squamous cell carcinomas developed in the sites of dermatosis in eight of the 397 younger and five of the 26 older beagles. The lesions resembled solar keratosis (solar dermatosis, actinic dermatosis or senile keratosis) in man. They developed under circumstances suggesting that solar radiation is involved in the pathogenesis, as it is in man.
Intestinal Tyzzer's Disease and Spirochetosis in a Guinea Pig
Authors: McLeod C. G. , Stookey J. L. , Harrington D. G. , White J. D.
Published: March 2010

Tyzzer's disease (bacillus piliformis infection) was diagnosed in a young guinea pig killed because of diarrhea and poor condition. There was necrosis and inflammation of the colon, cecum and ileum. Typical B. piliformis were in intestinal epithelial cells. Spirochetes were in large numbers in intestinal crypts and were often adjacent to the intracellular B. piliformis. Extracellular B. piliformis occasionally were surrounded by spirochetes.
Internal Hydrocephalus and Associated Periventricular Encephalitis in Young Dogs
Authors: Higgins R. J. , Vandevelde M. , Braund K. B.
Published: March 2010

Six dogs that had a sudden onset and rapid progression of neurological signs with enlargement of the cranial vault at 6-8 weeks old were believed to have congenital hydrocephalus. There were severe inflammatory and necrotizing lesions in periventricular sites in the brain. A bacterial infection may have been the cause of this process.
Intestinal Lesions Induced in Gnotobiotic Calves by the Virus of Human Infantile Gastroenteritis
Authors: Mebus C. A. , Wyatt R. G. , Kapikian A. Z.
Published: March 2010

Four gnotobiotic calves with intestinal lesions induced by third and fourth calf passages of the virus of human infantile gastroenteritis were studied by light microscopy, scanning and transmission electron microscopy, and by immunofluorescence. Calves, 25-72 hours old, were examined 0.5 hours, 3 hours, 7 hours, and 48 hours after the onset of diarrhea. Intestinal histology of infected calves was compared to that of two noninoculated gnotobiotic calves 48 and 72 hours old. The sequence of events in the small intestine was infection of the absorptive villous epithelial cells, replacement of the tall columnar villous epithelial cells with cuboidal and squamous cells, shortening of the villi, enlargement of reticular cells, lymphocytic infiltration of the villous lamina propria and repair.
Hypophysarer Zwergwuchs beim Deutschen Schäferhund [Pituitary Dwarfism in a German Shepherd Dog—author's trans]
Authors: Müller-Peddinghaus R. , El Etreby M. F. , Siefert J. , Ranke M.
Published: March 2010

Pituitary Dwarfism in a German Shepherd Dog

Pituitary dwarfism has been described in more than 20 German shepherd dogs. Some cases probably were caused by persistent cysts of Rathke's pouch. This is the first histopathological, immunohistochemical and endocrinological study.

A 13-month-old, 7-kg, dwarf purebred German shepherd bitch with alopecia and hyper pigmentation was admitted to the clinic for euthanasia. Retardation of growth was noticed when the dog was about two months old. No littermates had this condition. Two subsequent breedings from the same parents produced normal offspring.

The clinical parameters in our dog (hematology, function of liver and kidney) were normal. Grossly, the pituitary gland had small and large multiple cysts, which light microscopy showed to be exclusively within the adenohypophysis. The latter had pressure atrophy, and immunohistochemically showed only remnants of the hormone-producing cells (growth hormone—GH; prolactin—PRL; thyrotropin—TSH; luteinizing hormone—LH; adrenocorticotrophin—ACTH/MSH). The thyroid was relatively small, and histologically showed focally resting follicles without lumen.

Endocrinological studies showed a surprisingly high value for serum growth hormone (cGH 4.1 ng/ml; normal range 1.8–3.8 ng/ml as determined by a specific homologous radioimmunoassay) and a pathologically low serum somatomedin (SM 0.132; normal value more than 0.50 unit/ml, determined by 35S incorporation in piglet rib cartilage). Hypothyroidism was verified by a low T4 binding value (T4 0.9 μg/100 ml; normal 4.1 ± 0.9 μg/100 ml) and a low thyroid binding index (TBI 0.54; normal 0.61 ± 0.05). While ACTH was lowered (ACTH <10 pg/ml; normal 74–210 pg/ml), cortisol was normal (0.81 μg/100 ml; normal 0.5–2.5 μg/100 ml).

Pituitary dwarfism in the 13-month-old bitch can be ascribed to the persistence of one end of the ductus craniopharyngeus. Rathke's pouch. Pressure atrophy of the adenohypophysis led to the loss of most of the hormone-producing tissue. An increase in growth hormone with lowered somatomedin raises questions. We have no conclusive explanation for this, due to the present lack of knowledge of how growth is regulated. High growth hormone and low somatomedin values are found in Laron's syndrome in infants. The literature indicates that pituitary dwarfism in German shepherd dogs may be a hereditary autosomal recessive trait.
Distal Symmetrical Polyneuropathy in a Dog
Authors: Braund K. G. , Luttgen P. J. , Redding R. W. , Rumph P. F.
Published: March 2010

A 1.3-year-old Great Dane dog had a chronic progressive neurologic disease clinically expressed as a distal symmetrical polyneuropathy characterized by weakness and bilateral atrophy of bulbar and distal appendicular musculature. Qualitative and quantitative studies showed neurogenic atrophy of muscles below the elbow and stifle. There was Walleriantype degeneration. Schwann cell proliferation and cell bands of Büngner, and marked depletion of medium (5 to 8 μm) to large (9 to 15 μm) diameter myelinated fibers in the distal parts of appendicular and laryngeal nerves. Sensory (saphenous and superficial radial) and autonomic (sympathetic and dorsal vagal trunk) nerves were affected to a lesser degree. A distribution of distal axonal degeneration suggested a dying back process. The disease differed from classical dying back disorders by absence of axonal degeneration in selected pathways of the central nervous system.
Polycystic Disease of the Kidney and Liver in the Cairn Terrier
Authors: McKenna S. C. , Carpenter J. L.
Published: March 2010

Three related puppies with abdominal distention caused by nephromegaly and hepatomegaly had gross and histologic lesions in the kidney and liver similar to polycystic disease of children. Both kidneys were enlarged and reniform, and contained multiple fusiform or cylindrical cysts lined by cuboidal epithelium radiating through the cortex and medulla. Various amounts of connective tissue surrounded the cysts. The glomeruli and renal pelvis were normal. Histologically, the liver was diffusely subdivided by fibrous connective tissue extending from one portal triad to another. Within the connective tissue, there was proliferation of biliary epithelium, giving the gross appearance of multiple cysts within normal hepatic parenchyma.
Pancreatic Atrophy in Young Beagle Dogs
Authors: Prentice D. E. , James R. W. , Wadsworth P. F.
Published: March 2010

Six young Beagle dogs had non-inflammatory pancreatic atrophy associated with lack of weight gain and low serum protein levels. Histologically there was severe atrophy with loss of acinar architecture and absence of islets of Langerhans (type 1), or partial atrophy with preserved islets (type 2). The correlation between histological type and clinical severity was poor.
Neoplasien der Haut bei einem wildfarbenen Inzuchtstamm von Mastomys natalensis (WSA Gießen)
Authors: Rudolph R. L.
Published: March 2010

This is the first report on spontaneous and experimentally induced skin neoplasms of a wild-colored, black-eyed inbred line of Mastomys natalensis (WSA Gießen).

Seventeen spontaneous skin tumors from four animals and two experimentally induced tumors from two animals were examined. Routine histology and electron microscopy were done. For the transmission experiments, tumor suspension containing tumor cells and virus was applied to the depilated and scarified skin of the lumbar region of young Mastomys natalensis. The tumor suspension contained a mixture of squamous cell carcinoma and so-called keratoacanthoma cells, both taken from another inbred line of Mastomys natalensis (GRA Gießen). Depilation was done by application of aqueous suspension of equal parts of strontium sulfide and talcum powder. Narcosis was achieved by administration of 40 mg/kg body weight of sodium pentobarbital.

The 17 spontaneous neoplasms included 13 so-called keratoacanthomas, 2 squamous cell carcinomas, I papilloma and 3 localized epithelial proliferations. The two experimentally induced neoplasms were so-called keratoacanthomas. All tumors grew slowly and neither spontaneous regression nor metastasis was seen. All neoplasms showed keratinizing epidermal proliferation, with the greatest increase in prickle cells and granulosum cells. Two spontaneous and two experimentally induced “keratoacanthomas” were observed under an electron microscope. Papilloma-like virus particles were seen in all four. The virus particles were spaced regularly throughout the nuclei of the upper part of the granulosum cells and between parts of disintegrated cells of the horny layers.

The spontaneous and experimentally induced neoplasms of this WSA-line correspond to those of another inbred line (GRA Gießen) of Mastomys natalensis. The tumors are mutually transmissible. Both inbred lines are suitable for propagation of the Mastomys natalensis papilloma virus and for studying in greater detail the biological behaviour of this oncogenic agent in epithelial skin cells.
Ganglioneuromas in the Adrenal Medulla of F344 Rats
Authors: Reznik G. , Ward J. M. , Reznik-Schüller H.
Published: March 2010

Of 60,048 aging F344 rats, 28 had ganglioneuromas of the adrenal gland. The rats were between 58 and 122 weeks old; 25 of them between 93 and 122 weeks when the tumors were found. The neoplasms were composed of large or small typical ganglion cells with a large pale nucleus and a prominent, often eccentric, nucleolus. The ganglion cells usually were distributed throughout the medullary tumor and surrounded by various numbers of supporting cells, including Schwann's cell types, and capsular or satellite cells. Often there was no clear-cut border between ganglion cells and neoplastic pheochromocytes. Electron microscopy of re-embedded tissues showed neurosecretory granules and cytoplasmic areas with an extensive rough endoplasmic reticulum (Nissl substance) in the ganglion cells and axons. The Schwann's cells were surrounded by a basement membrane and formed long cytoplasmic extensions around the axons. Almost all ganglioneuromas were associated with neoplastic pheochromocytes which usually were located at the edge of the tumors.
Correlation of Dermal-Epidermal Laminar Lesions of Equine Hoof with Various Disease Conditions
Authors: Roberts E. D. , Ochoa R. , Haynes P. F.
Published: March 2010

Dermal and epidermal laminar lesions were correlated with acute intestinal, primary hepatic, septicemic, chronic laminar, and acute laminar diseases. Horses with acute intestinal disease had edema in the secondary dermal laminae. Those with hepatic disease had increased keratinization of the secondary epidermal laminae. Septicemia caused increased keratin formation in the primary and secondary epidermal laminae. Chronic laminitis caused architectural changes of the epidermal laminae characterized by hyperplasia and keratin formation of the basal epidermal layer. Horses with acute laminitis had epidermal necrosis, especially with peracute laminitis. Various insults to the epidermal laminae led to epithelial hyperplasia of the secondary epidermis with ventral deviation of the third phalanx.
Canine Laryngeal Oncocytomas
Authors: Pass D. A. , Huxtable C. R. , Cooper B. J. , Watson A. D. J. , Thompson R.
Published: March 2010

Solitary, protruding tumors were found in the wall of the larynx in three adult dogs with clinical upper respiratory obstruction. They were composed of cells with abundant granular acidophilic cytoplasm, the granularity caused by an unusually large number of mitochondria. The lesions were considered to be neoplasms arising from oncocytes as described in man. Oncocytomas have not been reported previously in domestic animals.
Morphological and Histochemical Characteristics of Pigments in Aging F344 Rats
Authors: Ward J. M. , Reznik-Schüller H.
Published: March 2010

Pigments found in spleen, lymph nodes, kidney, thyroid, adrenal, liver, ovary, central nervous system, heart and connective tissues of aging F344 rats were studied morphologically and histochemically. The morphology of the pigment accumulations depended on the tissue affected. Pigments resembling lipofuscin were found in most of these tissues. The ultrastructural appearance of siderosomes in splenic macrophages suggested that erythrocyte degradation was responsible for pigment production. Adrenal ultrastructure showed that lipofuscin-like material may have originated from degradation of lipid droplets of epithelial cells.
Neuronal Ceroid-Lipofuscinosis in Older Dachshunds
Authors: Vandevelde M. , Fatzer R.
Published: March 2010

A lysosomal storage disease with accumulation of periodic acid-Schiff- and Sudan black-positive autofluorescent granules in neurons occurred in one 51/2- and one 7-year-old dachshund. Ultrastructurally, the storage material consisted of membranous material arranged in stacks and fingerprint patterns. The disease was defined as ceroid-lipofuscinosis, and resembled a previously reported case in an adult dachshund.
Studies on Natural and Experimental Endometritis in Ewes
Authors: Sokkar S. M. , Kubba M. A. , Al-Augaidy F.
Published: March 2010

Of 100 uteri of ewes collected from a slaughterhouse, 44 had endometritis. These cases were classified as acute endometritis (18%), acute lymphocytic endometritis (59%), chronic non-suppurative endometritis (16%) and suppurative endometritis (6.8%). Aerobic bacteria were isolated from 26 uteri. The most commonly isolated bacteria were Escherichia coli, Corynebacterium pyogenes, and Staphylococcus aureus. These organisms then were inoculated into the uteri of normal ewes. None of the inoculated bacteria consistently produced any particular type of endometrial lesion.
Pathogenesis of Acute Toxoplasmosis in Specific-Pathogen-Free Cats
Authors: Parker G. A. , Langloss J. M. , Dubey J. P. , Hoover E. A.
Published: March 2010

Systemic toxoplasmosis was produced in specific-pathogen-free cats by intravenous inoculation with Toxoplasma gondii tachyzoites. Infectious organisms were recovered from all tissues studied, but the number of organisms recovered from liver, lungs and spleen was 10-fold to 10,000-fold higher than from heart and brain. The occurrence and severity of Toxoplasma-induced lesions correlated with the number of infectious organisms recovered from the various tissues. In nonlymphoid tissues, the Toxoplasma-associated lesions consisted of multifocal necrosis, usually with demonstrable organisms. Lesions in the spleen and mesenteric lymph nodes consisted of reticuloendothelial and lymphoid hyperplasia, with few demonstrable organisms. Pneumonitis was severe and sometimes fatal in the early stages of systemic toxoplasmosis. Light- and electron-microscopic studies showed that the earliest lung lesions were randomly distributed infiltrates of neutrophils, eosinophils, and mononuclear cells into alveolar walls. Later lesions were diffuse alveolar necrosis, pneumocytic hyperplasia, and extensive fibrinocellular exudates in alveoli. Tachyzoites were present in cytoplasmic vacuoles of fibroblasts, macrophages, type I and II pneumocytes, bronchiolar epithelial cells, bronchiolar smooth muscle cells, endothelial cells, neutrophils, eosinophils, and circulating monocytes. Replication of organisms was found in all parasitized cell types except neutrophils and eosinophils.
Equine Onchocerciasis: Lesions in the Nuchal Ligament of Midwestern U.S. Horses
Authors: Schmidt G. M. , Krehbiel J. D. , Coley S. C. , Leid R. W.
Published: March 2010

Nuchal ligaments from midwestern U.S. horses infected with adult Onchocerca sp. were studied. The prevalence of Onchocerca sp. infection in horses increased with age. Ten percent of horses less than one year old were infected, 28% of horses one to five years old, 48% of horses six to 15 years old, and 90% of horses over 16 years old.

Lesions in Onchocerca sp.-infected nuchal ligaments varied with age of the horse. Horses less than five years old had few or no lesions, whereas most horses six to 15 years old had focal mineralization and granuloma formation around adult worms. In infected nuchal ligaments of horses over 16 years old, mineralization was much greater and fewer normal parasites were found. Our data suggest that infection by viable parasites is terminated naturally.
Pathology of Experimental CV777 Coronavirus Enteritis in Piglets. I. Histological and Histochemical Study
Authors: Coussement W. , Ducatelle R. , Debouck P. , Hoorens J.
Published: March 2010

Sixteen cesarean-derived colostrum-deprived piglets were infected oronasally with CV777 coronavirus on the second or third day of life. Two uninfected piglets were controls. They were killed at 96 and 120 hours after birth. After an incubation period of 22 to 36 hours, all principals showed severe diarrhea. The principals were killed between 12 and 120 hours after infection.

Exfoliation of enterocytes was seen first in the piglet killed 24 hours after infection (two hours after the diarrhea began). From that time on, shortening and fusion of villi was present in all small intestinal parts. Affected cells showed vacuolation. The histochemical study showed that infected piglets had decreased activity of all four enzymes studied. The light microscope showed no lesions in the absorptive colonic epithelium.

The significance of the lesions in relation to intestinal dysfunction is discussed, and lesions are compared to those of transmissible gastroenteritis and porcine rotavirus infection.
Intestinal Lesions in Specific-Pathogen-Free Lambs Associated with a Cryptosporidium from Calves with Diarrhea
Authors: Angus K. W. , Tzipori S. , Gray E. W.
Published: March 2010

Small and large intestines of seven specific pathogen-free lambs infected with cryptosporidia from calves with diarrhea were examined by scanning and transmission electron microscopy and by light microscopy. The small intestine was infected in all the lambs, and the cecum and colon in three. Small intestinal alterations were severe villous atrophy and dilatation of the crypts of Lieberkühn. Epithelial cross-bridging between contiguous villi caused much villous fusion. Epithelial cells constituting the bridges were connected by desmosomal junctions, and were continuous with the epithelial coverings of the associated villi. The lamina propria was heavily infiltrated with neutrophil leukocytes. Infected crypts in cecum and colon were dilated and devoid of mucus-secreting cells, while the ridges between crypts were hypertrophied, and the lamina propria was infiltrated by neutrophils. Cell vegetations with adherent bacteria were present in the surface intestinal epithelium of two lambs infected for 11 and 14 days, respectively. No adherent bacteria were seen in any site in lambs killed up to six days post-inoculation.
Sequential Pathological Study of Experimental Porcine Adenovirus Enteritis
Authors: Ducatelle R. , Coussement W. , Hoorens J.
Published: March 2010

The sequential enteric lesions of experimental porcine adenovirus strain 6618 infection were studied in 18 hysterotomy-derived, colostrum-deprived piglets, by histology, transmission electron microscopy, and an immunoperoxidase technique.

Viral particles could be seen in altered epithelial cells of the lower small intestine from 24 hours until 16 days after inoculation. With the immunoperoxidase technique, viral antigen could be found in epithelial cells at 45 days after challenge.

Destruction of epithelial cells and shortening of villi could be related directly to the presence of the virus.

Histology of the lower jejunum and ileum, which demonstrates intranuclear inclusion bodies, is proposed as a useful diagnostic technique.
Ultrastructural Changes in the Small Intestine of Neonatal Calves with Enteric Colibacillosis
Authors: Pearson G. R. , Logan E. F.
Published: March 2010

The small intestines of calves inoculated orally with the enteropathogenic strain of Escherichia coli 0101:K'B41′, K99 were examined by electron microscopy at 3, 6, 12, 16, 21, 36, 69, 70 and 72 hours after inoculation. The challenge organism adhered to the mucosa of the distal small intestine from six hours post-inoculation. Bacteria were separated from the microvillous brush border by a gap of 200 to 300 nm in which bacterial fimbriae and the microvillous glycocalyx were seen. Bacteria never were found in epithelial cells but were present in macrophages in the lamina propria from 12 hours. At three and six hours, cytopathic changes were not seen in the small intestine, but from 12 hours epithelial cells on affected villi had blunt and thick microvilli and contained cytoplasmic inclusions. Epithelial cells were seen frequently in the process of extrusion from the villi, either singly, in small groups, or as ribbons of cells. Intervillous bridges, characteristic of villous fusion, were seen frequently from 69 hours.
A Tubal Pregnancy in a Rhesus Monkey (Macaca mulatta)
Authors: Jerome C. P. , Hendrickx A. G.
Published: March 2010

Tubal pregnancy was diagnosed on histological section of a nodule within the uterine tube of a multiparous rhesus monkey. Clinical signs were anorexia and weight loss. The tube contained a placenta of approximately 35 days gestation, but no recognizable embryo or amnion. The ipsilateral ovary contained a degenerating corpus luteum.
Murine Respiratory Mycoplasmosis in LEW and F344 Rats: Strain Differences in Lesion Severity
Authors: Davis J. K. , Cassell G. H.
Published: March 2010

Pathogen-free weanling rats of the LEW and F344 strains were caged together for two months to eliminate microbial and environmental differences, and then infected intranasally with 10-fold dilutions of viable Mycoplasma pulmonis. At necropsy 28 days postinoculation, F344 rats had no gross lung lesions, even those given the maximum dose of 1.4 X 109 colony-forming units of M. pulmonis. LEW rats often had extensive gross lesions with a gross-pneumonia-dose50 of 1.1 X 107 colony-forming units/rat. Histological examination of the respiratory tract (nasal passages, larynges, tracheae, and lungs) and tympanic cavities showed both qualitative and quantitative differences in lesions between the two strains, particularly in the lungs. Hyperplasia of bronchus-associated lymphoid tissue occurred in both strains, but was more extensive in LEW rats. Atelectasis, alveolar consolidation (due primarily to mononuclear inflammatory cells), and suppurative bronchitis and bronchiolitis were seen only in LEW rats. Infiltrates of lymphoid cells into the lungs distal to bronchi and around blood vessels also were seen primarily in LEW rats. These differences between the two rat strains provide excellent model systems with which to dissect the role of cell responses in the pathogenesis of a naturally occurring chronic lung disease.
Ultrastructural Evaluation of Acute Encephalitis and Hydrocephalus in Dogs Caused by Canine Parainfluenza Virus
Authors: Baumgärtner W. K. , Krakowka S. , Koestner A. , Everman J.
Published: March 2010

Intracranial infection of neonatal dogs with canine parainfluenza virus (strain 78–238) progressed from an acute phase of encephalitis to a chronic phase of internal hydrocephalus. Acute encephalitis was characterized ultrastructurally by laminar cortical necrosis, neuronal degeneration, neocapillary formation, reactive gliosis, and ependymitis. Viral nucleocapsids were seen in the cytoplasm of neurons.

Ultrastructural lesions in hydrocephalic dogs were restricted to ventricular surfaces. The earliest light microscopic change in ependymal cells occurred four weeks post-infection and consisted of segmental loss of ependymal cells. Dogs killed at three and six months postinfection had quantitatively similar ultrastructural alterations in ependymal cells regardless of the extent and severity of hydrocephalus. The shape of these cells changed from cuboidal to squamous. There was progressive loss of cilia and cell organelles along with a concomitant increase of cytoplasmic filaments. Viral nucleocapsids and inflammatory cells were not present in convalescent hydrocephalic dogs. These results suggested that virus-associated hydrocephalus can occur in the absence of obvious viral persistence in ependymal cells and in the absence of inflammation in the ventricular system.
Light and Electron Microscopic Pulmonary Lesions Associated with Retained Microfilariae in Canine Occult Dirofilariasis
Authors: Castleman W. L. , Wong M. M.
Published: March 2010

Lungs from dogs infected with adult, gravid Dirofilaria immitis but without microfilaria circulating in systemic vessels were studied by light and transmission electron microscopy. Microfilariae were seen within the pulmonary microvasculature and in interstitial areas of interalveolar septa. An acute inflammatory reaction characterized by aggregates of eosinophils, neutrophils, macrophages and lymphocytes was associated with intact microfilariae. Necrotic and fragmented microfilariae were surrounded by macrophages and epithelioid cells. Other lesions in interalveolar septa of dogs with chronic occult dirofilariasis included endothelial degeneration and hypertrophy, perivascular aggregates of plasma cells, hypertrophy and hyperplasia of smooth muscle cells, and interstitial fibrosis. The findings suggest that a cell-mediated hypersensitivity reaction is at least partially responsible for retention of microfilariae in pulmonary parenchyma of dogs with occult dirofilariasis.
Age-Related Changes in Peripheral Nerves of the Dog. I. A Morphologic and Morphometric Study of Single-Teased Fibers
Authors: Braund K. G. , McGuire J. A. , Lincoln C. E.
Published: March 2010

Incidence of lesions in single-teased myelinated fibers and the relationship between internodal length and fiber diameter were studied by morphologic and morphometric techniques on common peroneal and ulnar nerves of 28 dogs between three months and 15 years of age that were free of neuromuscular disease. Minimal lesions were seen in nerves of dogs under ten years of age, usually involving less than 3% of the teased fibers; however, in older dogs, the mean incidence of lesions that included axonal degeneration and segmental demyelination and remyelination, increased to 6% and 9% in ulnar and common peroneal nerves, respectively. A positive correlation (p < 0.0001) between internodal length and fiber diameter was found in both nerves from immature and mature dogs, but slopes of regression lines were reduced in older dogs.
Age-Related Changes in Peripheral Nerves of the Dog. II. A Morphologic and Morphometric Study of Cross-Sectional Nerve
Authors: Braund K. G. , McGuire J. A. , Lincoln C. E.
Published: March 2010

Qualitative histologic studies and quantitative measurements were made on cross-sectional preparations of common peroneal and ulnar nerves of 32 neuromuscular disease-free dogs from birth to 15 years of age, to provide normative data not available previously. Minimal lesions were seen in nerves of dogs from birth to seven years; however, in older dogs, the incidence of axonal degeneration and segmental demyelination and remyelination increased. Total fiber density of both nerves was over 40,000 fibers/mm2at birth and declined rapidly during the first six to nine months to level off at about 10,000 fibers/mm2by one year of age. Density of small (< 5 μm) and large (≥ 5 μm) diameter fibers attained adult values by one year of age. The frequency distribution of the myelinated fibers was unimodal at birth and became bimodal between three and six months of age. The peaks of the small and large fiber groups occurred at 3 μm and 6 μm, respectively. Larger diameter fibers (10 μm to 12 μm) reached adult values between nine months and one year of age. A 2.5 fold increase in mean fiber diameter occurred during the first year of life. There was no statistically significant change in any histometric parameter after maturity (approximately one year of age).
The Pathology of Gomen Disease: A Cerebellar Disorder of Horses in New Caledonia
Authors: Hartley W. J. , Kuberski T. , LeGonidec G. , Daynes P.
Published: March 2010

The lesions of Gomen disease consist of widespread loss of Purkinje cells with extensive deposition of lipofuscin pigment in neurones in most areas of the central nervous system. We suggest these two disease processes are related and the entity may be an acquired environmental neuronal lipofuscinosis.
Experimental Vesicular Exanthema of Swine Virus and San Miguel Sea Lion Virus Infection in Phocid Seals
Authors: Gelberg H. B. , Mebus C. A. , Lewis R. M.
Published: March 2010

Studies with vesicular exanthema of swine virus type A48 and San Miguel sea lion virus type 2 indicated that phocid (harp) seals could be infected with these caliciviruses, but the resultant disease was inapparent or mild and self-limiting. As in swine, lesions were limited to sparsely haired or nonhaired regions of the skin and tongue. Unlike swine, however, antivirus titers in seals were low and transient.