bluuebunny/crossref_metadata_2025 huggingface dataset:
Entry and Intracellular Localization of Brucella spp. in Vero Cells: Fluorescence and Electron Microscopy
Authors: Detilleux P. G. , Deyoe B. L. , Cheville N. F.
Published: March 2010

Vero cells were inoculated with the six species of Brucella ( B. abortus, B. melitensis, B. suis, B. neotomae, B. canis, and B. ovis) and examined by fluorescence and electron microscopy. All Brucella spp. were internalized by Vero cells. In all cells except those inoculated with B. canis, the numbers of intracellular brucellae increased with time after inoculation. Intracellular brucellae were first seen within phagosomes and phagolysosomes. Subsequent localization within cisternae of the rough endoplasmic reticulum was seen with all species of Brucella, except B. canis, which was restricted to phagolysosomes. Although rough brucellae were more adherent and entered a greater number of Vero cells, intracellular replication occurred in a larger percentage of cells with smooth rather than with rough brucellae. These results suggest that phagocytosed Brucella spp. are transferred 1) to cisternae of the rough endoplasmic reticulum, where unrestricted bacterial replication takes place; or 2) to phagolysosomes in which Brucella spp. fail to replicate. The various strains of Brucella spp. differ in their ability to induce their own transfer to the rough endoplasmic reticulum.
Neosporosis in Cats
Authors: Dubey J. P. , Lindsay D. S. , Lipscomb T. P.
Published: March 2010

Six cats (Nos. 1-6) were inoculated intramuscularly with (1 × 106) and orally (5 × 105) tachyzoites of Neospora caninum. Three (Nos. 1-3) of the six cats were given 40 mg/kg methylprednisolone acetate 7 days before and on the day of inoculation with N. caninum tachyzoites, and three cats (Nos. 4-6) were not given methylprednisolone acetate. Two of the cats (cat Nos. 1 and 2) given methylprednisolone acetate died suddenly. Cat No. 1 died 8 days post-inoculation, and cat No. 2 died 16 days post-inoculation. Cat No. 3 was euthanatized 21 days post-inoculation. Cat No. 1 had lesions of gram-positive bacterial septicemia. Necrotizing encephalitis, myelitis, disseminated skeletal muscle necrosis, hepatic necrosis, interstitial pneumonia, and renal tubular necrosis were the main lesions in cat Nos. 2 and 3. The cats that were not given methylprednisolone acetate remained clinically normal except for slight weight loss in cat No. 6. All three of these cats were euthanatized 55 days post-inoculation. Mild myositis and encephalitis were noted on microscopic examination of tissues from these three cats. Neuromuscular lesions were not seen in six control cats (Nos. 7-12) not inoculated with N. caninum and euthanatized 21 or 22 days after administration of the first of two doses of methylprednisolone acetate (40 mg/kg), given at a weekly interval.
Histologic and Ultrastructural Studies of Dermal Sarcoma of Walleye (Pisces: Stizostedion vitreum)
Authors: Martineau D. , Bowser P. R. , Wooster G. , Forney J. L.
Published: March 2010

Sixty-seven adult walleye fish were examined by light and transmission electron microscopy. The fish were affected by a mesenchymal tumor previously termed Walleye Dermal Sarcoma that commonly affects up to 27% of the population seasonally. Biopsies from 24 fish were collected, and complete postmortem examinations were performed on 43 fish. Grossly, the tumors had the appearance of randomly distributed, often clustered, spherical nodules, 2-5 mm in diameter with a smooth and often ulcerated surface. The tumors arose from the superficial surface of scales and consisted of fibroblast-like cells separated by a moderate amount of collagen (43/67) or osteoid material (24/67). Lymphocytic infiltration (28/67) associated with vacuolar degeneration of tumor cells (28/67) and centrally located coagulation necrosis (30/67) were observed. Although tumor cells were often highly anaplastic, no local invasions or metastases were present. In contrast with previous descriptions of this tumor, no viral particles could be observed electron microscopically. The variably anaplastic appearance of the tumor, its biological behavior, and its restriction to dermis are features in common with canine cutaneous histiocytoma and equine sarcoid. The multicentric origin, the restriction to the dermis, and the absence of invasion or metastases of Walleye Dermal Sarcoma differ from retrovirus-induced avian and murine sarcomas that arise locally, that invade, and that often metastasize.
Bovine Fetal Encephalitis and Myocarditis Associated with Protozoal Infections
Authors: Barr B. C. , Anderson M. L. , Blanchard P. C. , Daft B. M. , Kinde H. , Conrad P. A.
Published: March 2010

Bovine fetuses submitted to the California Veterinary Diagnostic Laboratory System were evaluated during a 2-year period (1987 to 1989) for the presence of multifocal necrotizing nonsuppurative encephalitis, nonsuppurative myocarditis, or tissue protozoa. Eighty-two of 445 (18%) fetuses submitted met these histologic criteria. Fetuses were from 54 dairy and two beef herds located throughout the state. In 17 fetuses (21%) protozoa were found in fetal tissues. Protozoa were found in brain parenchyma of ten fetuses (12%), in endothelial cells in four fetuses (5%), in cardiac myofibers in one fetus (1%), and were associated with endothelial cells in two fetuses (2%). In most fetuses there were no significant gross pathologic findings other than autolysis. While aborted fetuses were from 3 to 9 months gestation, the majority were between 5 and 7 months gestation. They were submitted year round, but more were seen in the fall and winter months. Additional salient histologic features included portal nonsuppurative hepatitis, focal hepatic inflammation and necrosis, and focal nonsuppurative myositis. Nonsuppurative inflammation was also found in decreasing frequency, in the adrenal medulla, kidney, mesentery or abdominal fat, placenta, and lung. In two fetuses (Nos. 1 and 2), the location and morphology of the protozoa were compatible with Sarcocystis spp. The identity of protozoa in the remaining 15 fetuses is unknown. The histopathologic changes in these 82 fetuses and the presence of protozoa in 21% of the fetuses suggest these abortions are due to fetal protozoal infections.
Morphologic Aspects and Morphogenesis of Blood Cysts on Canine Cardiac Valves
Authors: Takeda T. , Makita T. , Nakamura N. , Kimizuka G.
Published: March 2010

We investigated retrospectively the morphologic aspects of blood cysts of the atrioventricular valve in eight Beagle dogs and clarified the morphogenesis of the lesions. Study of serial sections revealed that the cysts communicate with the blood vessels; however, they showed no connection with the valve surface. Immunohistochemically, the thin endothelium of the lesions showed positive staining for factor VIII-related antigen. Histologic studies of a variety of sizes of blood cysts revealed four basic stages of blood cyst formation: 1) initially, the involved blood vessel undergoes only a slight enlargement that is not grossly detectable; 2) next, the vessel becomes moderately or markedly dilated and contains a large number of erythrocytes. The changes of this stage are macroscopically detectable; and 3) then, blood flow is arrested partly in the cystic lesion, followed by degeneration and necrosis of the cyst. At this third stage, fibrous tissue or dense collagenous connective tissue is usually seen surrounding the cyst; 4) and finally, metaplastic bone is formed within the lesion. Colloidal carbon infusion into the valves of normal canine hearts revealed the presence of an extensive, dense arrangement of blood vessels in the septal leaflet of the tricuspid valve, which usually is the recognized site to develop blood cysts.
Veno-occlusive Disease in Snow Leopards (Panthera uncia) from Zoological Parks
Authors: Munson L. , Worley M. B.
Published: March 2010

Livers from 54 snow leopards, 4 days to 23 years old, that had died in 23 US zoos, were evaluated histopathologically to determine if the hepatic fibrosis, which has been noted to be prevalent in this species, was due to chronic active hepatitis from hepadnaviral infection, Ito cell proliferation, or hemosiderosis. Forty-two of 54 snow leopards had subintimal vascular fibrosis with partial or total occlusion of central and sublobular veins (veno-occlusive disease) of unknown origin. All 21 leopards older than 5 years were affected. Four leopards had chronic active hepatitis, and 12 leopards had cholangiohepatit])L but these lesions were not connected anatomically to central and sublobular venous fibrosis. Hepatocellular and Kupffer cell siderosis and Ito cell proliferation were prevalent and often coexisted with perisinusoidal, central, and sublobular venous fibros])L but fibrosis was present in leopards without siderosis or Ito cell proliferation. The pattern and prevalence of veno-occlusive disease in these leopards was similar to that reported in captive cheetah ( Acinonyx jubatus), suggesting that a common extrinsic factor may cause the majority of hepatic disease in these large felid animals in captivity.
Reproduction of Edema Disease of Swine with Purified Shiga-like Toxin-II Variant
Authors: MacLeod D. L. , Gyles C. L. , Wilcock B. P.
Published: March 2010

Twenty-one weaned Yorkshire-Landrace pigs were injected intravenously with graded doses of purified Shiga-like toxin-II variant (edema disease toxin). In a preliminary study, three pigs (Nos. 1, 2, 3) were injected with 48, 24, and 12 ng, respectively, of SLT-IIv/kg of body weight. Subsequently, three groups (Nos. 4, 5, 6) of six pigs each were injected with 6, 3, and 1.5 ng, respectively, of SLT-IIv/kg of body weight. Severe clinical signs and histologic lesions characteristic of edema disease developed in pigs Nos. 1, 2, and 3, and all six pigs in group No. 4. Eight of these pigs were euthanatized in extremis (mean time to death was 34 hours) and one died of the disease (52 hours). Moderate signs and lesions of edema disease were observed in all pigs in group No. 5, and three pigs were euthanatized (mean time to euthanasia was 42 hours). Mild signs and lesions were observed in three pigs in group No. 6. The most common gross pathologic changes were edema of the eyelids, submucosa of the stomach, and mesentery of the spiral colon and hemorrhage of the colon and cerebellum. Microscopic lesions were associated with vascular injury and included vessel necrosis, perivascular edema and hemorrhage, and superficial colonic and cecal erosions. The vascular lesions were observed in the cerebellar folia, submucosa and mucosa of the stomach, cecum, colon, and sporadically in the retina. None of the clinical signs associated with endotoxin were observed.
Accumulation of 2,8 Dihydroxyadenine in Bovine Liver, Kidneys, and Lymph Nodes
Authors: McCaskey P. C. , Rigsby W. E. , Hinton D. M. , Friedlander L. , Hurst V. J.
Published: March 2010

A variety of tissues from 20 cattle slaughtered at federally inspected facilities contained abundant light green to greenish-yellow material. Gross lesions were most common in the liver and hepatic lymph nodes. Less frequent lesions were present in the mediastinal, renal, intercostal, and gastric lymph nodes. The material was most prominent in the portal triads, and in the medullary sinuses of the lymph nodes, at times occupying up to one half of the nodal mass. Renal calculi were present in one animal.

Histologically, the condition was characterized by the intracytoplasmic accumulation of innumerable brown, acicular crystals in hepatocytes, macrophages, and renal tubular epithelial cells. Less frequent large aggregates of extracellular crystals were found in the lumens of renal tubules and in portal triads. Crystals were highly birefringent when examined using polarized light. The crystals were identified as 2,8 dihydroxyadenine using X-ray diffraction, electron diffraction, infrared spectroscopy, and mass spectrometry.

In mammals, adenine is normally converted to adenylate by the enzyme adenine phosphoribosyltransferase. When adenine phosphoribosyltransferase is absent, deficient, or inhibited, adenine is oxidized to 2,8 dihydroxyadenine, which is extremely insoluble at physiological pH. In human beings, an autosomal recessive disease known as 2,8 dihydroxyadeninuria is caused by a deficiency of adenine phosphoribosyltransferase.
Comparison of Growth and Differentiation of Normal and Neoplastic Canine Keratinocyte Cultures
Authors: Suter M. M. , Pantano D. M. , Flanders J. A. , Augustin-Voss H. G. , Dougherty E. P. , Varvayanis M.
Published: March 2010

Neoplastic canine keratinocytes derived from a spontaneous oral squamous cell carcinoma were maintained in culture for more than 45 passages. The presence of desmosomes and keratin filaments was demonstrated by electron microscopy and immunohistochemistry. The keratinocytes were grown in two different culture conditions to induce variations in the stage of differentiation, i.e., in submerged cultures and at the air-liquid interface. For comparison, normal canine keratinocytes were grown under the same conditions. Anisocytosis was present in neoplastic cultures grown submerged in medium. Grown at the air-liquid interface, neoplastic keratinocytes differentiated into a well-organized, multilayered stratified squamous epithelium analogous to normal keratinocytes. Rare areas of irregular growth and formation of whorls were detected. Expression of lectin binding sites and specific cell surface antigens of neoplastic and normal keratinocytes demonstrated marked similarities between the two cell lines. Neoplastic cells lacked certain surface antigens that are present on normal cells. Squamous cell carcinoma cells grew faster than normal canine keratinocytes as demonstrated by growth curve evaluation. Neoplastic keratinocytes responded to growth stimulation by epidermal growth factor and cholera toxin as do normal keratinocytes. Neoplastic cells grown in medium lacking these factors proliferated faster than growth factor stimulated normal keratinocytes.
Sexual Dimorphism of the Normal Rat Mammary Gland
Authors: Cardy R. H.
Published: March 2010

Sexual dimorphism is a routinely encountered but previously unreported feature of the normal rat mammary gland. Forty male and 40 female F344 rats, 19 weeks of age, were examined retrospectively to document histologic differences that are very apparent when mammary glands of males and females of the same age are compared.

Development of the mammary gland starts in utero, and there is reported to be little morphologic difference between males and females at birth. By 19 weeks of age, however, the differences are very noticeable. The mammary glands of females, comprised of scattered tubular ducts and alveolar structures that have distinct lumina lined, usually, by a single layer of cuboidal epithelium, are characterized as tubuloalveolar. In young males, mammary tissue is generally more florid than in females of the same age. There are, scattered within the hypodermis, larger, more contiguous, lobular groups of cells that are distinct for their lack of obvious tubular or ductal orientation. The cells, arranged into alveoli, are generally characterized by abundant, foamy, eosinophilic cytoplasm containing distinct, variably-sized vacuoles. Alveolar lumina are mostly indistinct but may contain evidence of secretory activity.

To emphasize the importance of this difference, selected results of a routine toxicity study are discussed in which the mammary glands of male rats, exposed for 52 weeks to cis-N-(1-benzyl-2-methylpyrrolidin-3-yl)-5-chloro-2-methoxy-4-methyl-aminobenzamide, a reported dopamine antagonist, underwent distinctive histomorphologic changes. As a result of exposure to this compound, the lobuloalveolar structure described as normal for male rats assumed characteristics of a tubuloalveolar morphology indistinguishable from that seen in the unexposed females. Female mammary glands were unaffected by exposure to the same material.
Lectin Histochemistry of Trachea and Lung of Healthy Turkeys (Meleagris gallopavo) and Turkeys with Pneumonia
Authors: Ackermann M. R. , Cheville N. F. , Detilleux P. G.
Published: March 2010

Thirteen lectins were used to characterize lectin-binding specificity of glycoconjugates on sections of formalin-fixed lung and trachea from seven normal turkeys, two turkeys with acute pneumonia, and two turkeys with chronic pneumonia. Neuraminidase was used to digest sialic acid residues. One N-acetylgalactosamine-binding lectin and two N-acetylgalactosamine/galactose-binding lectins stained the apical membrane and cytoplasm of multifocal cells that lined air atria and hyperplastic granular cells. Other lectins in these groups stained ciliated cells of the trachea and bronchi and air capillary epithelial cells. Sialic acid residues were on apical surfaces of ciliated and nonciliated tracheal and bronchial lining cells, air capillary epithelial cells, and vascular endothelial cells. Mannose/glucose-binding lectins stained reticular and elastic fibers in the lamina propria of trachea, primary and secondary bronchi, and the tunica adventitia of arteries and veins. By transmission electron microscopy, colloidal gold- Arachis hypogaea (peanut agglutinin) labeled microvilli on the apical surface of mature granular cells. The L-fucose-binding lectin, in addition to several other lectins, stained nonspecifically in both trachea and lung. These studies show that granular cells that line air atria can be identified with lectins of N-acetylglucosamine and N-acetylgalactosamine/galactose groups, and that apical surfaces of epithelial cells and endothelial cells in the trachea and lung express terminal sialic acid residues.
Passive Role of Articular Chondrocytes in the Pathogenesis of Acute Meniscectomy-induced Cartilage Degeneration
Authors: Bendele A. M. , Bean J. S. , Hulman J. F.
Published: March 2010

The importance of viable articular chondrocytes and enzymes or factors from surgically traumatized synovium in the pathogenesis of acute meniscectomy-induced cartilage degeneration was examined in guinea pigs (nine groups of five animals each). Iodoacetate injected intra-articularly was used to kill articular chondrocytes of guinea pigs prior to meniscectomy to determine if they were active participants in the acute lesion induction. Lesions of similar severity to those occurring in animals with viable chondrocytes at the time of surgery were observed, suggesting that the chondrocytes were not actively involved in the pathogenesis in this group. In an additional group of guinea pigs in which chondrocytes were killed by iodoacetate, the medial collateral ligament was transected to determine if acute degenerative changes could be induced in acellular cartilage exposed to a surgical manipulation that does not by itself induce lesions but does expose cartilage to enzymes/factors from traumatized synovium. Transecting the medial collateral ligament and entering the joint space without induction of instability via meniscectomy did not result in histologic evidence of cartilage damage. This suggests that synovial trauma and mild inflammation were insufficient to induce matrix degeneration in the absence of abnormal load bearing. In further support of this, guinea pigs subjected to unilateral sciatic neurectomy at the time of meniscectomy were protected against development of acute cartilage degeneration.

Results of this study suggest that articular cartilage devoid of viable chondrocytes at the time of meniscectomy responds acutely in much the same way as intact cartilage subjected to this procedure.
A Preliminary Study of the Pathogenesis of Foot-and-mouth Disease Virus Using in situ Hybridization
Authors: Brown C. C. , Olander H. J. , Meyer R. F.
Published: March 2010

Five adult guinea pigs were inoculated intraepithelially in the right hindfoot pad with foot-and-mouth disease virus. Animals were euthanatized with carbon dioxide at 4, 10, 24, 48, and 72 hours post-inoculation. Generalized disease developed in the guinea pigs, as evidenced by depression and inappetance by 24 hours post-inoculation and by the formation of vesicles in the noninoculated hindfoot pad by 48 hours post-inoculation. By in situ hybridization, using a 500 base pair biotinylated RNA probe, viral nucleic acid was detected in the noninoculated fore- and hindfoot pads as early as 10 hours post-inoculation, well before any pathologic changes associated with foot-and-mouth disease virus infection were detected. These tissues remained consistently positive for the presence of viral nucleic acid up to the end of the experiment. At this time, in the forefoot pad, even though virus had first been detected with certainty in that tissue 62 hours previously, there was still no microscopic evidence of foot-and-mouth disease virus-induced damage in the histologic section. Similarly, tongue tissue was positive by in situ hybridization at 4, 48, and 72 hours post-inoculation, yet there was never any microscopic evidence of degeneration or vesicle formation. From this preliminary study, it appears that, in the guinea pig, the virus is widely disseminated to foot pads and tongue, with epidermal lesions resulting only in selected areas.
Congenital Anemia, Dyskeratosis, and Progressive Alopecia in Polled Hereford Calves
Authors: Steffen D. J. , Leipold H. W. , Gibb J. , Smith J. E.
Published: March 2010

A new syndrome of anemia, alopecia, and dyskeratosis was identified in Polled Hereford calves in this study. Cutaneous changes included hyperkeratosis and hair loss around the muzzle and ear margins, which progressed to a generalized alopecia and hyperkeratotic dermatitis. Histologically, orthokeratotic hyperkeratosis with dyskeratosis of epidermal and follicular keratinocytes was present. Alopecia was correlated with dyskeratosis of Huxley's layer and an increasing proportion of follicles in the telogen phase of the hair cycle. Dermatitis was characterized by a mild dermal mononuclear cell infiltrate and mild lymphocytic perivascular dermatitis. The anemia present at birth was nonprogressive and was classified as normochromic and normocytic to macrocytic. Reticulocytosis was absent, but bone marrow was markedly hyperplastic. Nuclear cytoplasmic asynchrony of the rubricyte and metarubricyte stages occurred in the bone marrow. Abnormal rubricyte nuclei and maturation arrest at the late rubricyte stage were common. Cytologic features of the erythroid series are similar to those of type I congenital dyserythropoietic anemia of human beings. Genealogic features suggest that this is a primary hereditary defect. The mode of inheritance, however, remains to be determined.
Ultrastructural Features of Alveolar Lesions in Induced Respiratory Syncytial Virus Pneumonia of Calves
Authors: Bryson D. G. , McConnell S. , McAliskey M. , McNulty M. S.
Published: March 2010

Ultrastructural changes occurred in alveolar epithelium in the acute and repair stages of induced respiratory syncytial virus pneumonia induced in eight calves (calf Nos. 1–7, 3 to 6 days old and calf No. 8, 2 weeks old), using a bovine strain of respiratory syncytial virus. Five of the calves were Friesians, three were Hereford x Friesians, and all were male. Tissues from three mock-infected control calves (two Friesian, one Hereford x Friesian) were also examined. Evidence of respiratory syncytial virus infection was observed in both type I and type II pneumocytes from day 4 to day 8 after infection. Infection of type I pneumocytes frequently resulted in necrosis. The response of type II pneumocytes to respiratory syncytial virus infection varied and included hypertrophy, hyperplasia, and syneytial formation. In some infected type II pneumocytes, there were numerous irregular projections of the cell surface, associated with viral budding. Hypertrophy and hyperplasia of type II pneumocytes, epithelial syncytium formation, and irregular cytoplasmic projections from epithelial cells caused considerable thickening of respiratory membrane and occlusion of alveolar lumina. Neutrophils were frequently observed in close association with virus-infected epithelial cells, but evidence of respiratory syncytial virus infection and replication was not observed in alveolar macrophages or neutrophils.

Proliferation of type II pneumocytes appeared to play a major role in maintaining the integrity of the alveolar epithelium during the acute stage of the experimental pneumonia. Increased numbers of type II pneumocytes were present on alveolar walls, particularly from 4 to 8 days after infection, and some alveoli were lined entirely by this cell type. In some areas, however, squamous epithelial cells were also involved in covering exposed alveolar basement membrane.
“Lipomatous” Hamartomas and Choristomas in Inbred Laboratory Mice
Authors: Adkison D. L. , Sundberg J. P.
Published: March 2010

In a retrospective study, 37 male and 19 female inbred laboratory mice, from 1 to 36 weeks of age, were diagnosed with “lipomatous” hamartomas or choristomas from nearly 10,000 mice examined at necropsy over a 24-month period. Hamartomas and choristomas were found to be rare, noninherited tumorlike conditions that occurred spontaneously in 18 inbred strains of mice with a predominance of the conditions in the C3H/HeJ and C57BL/6J strains. Prevalence between strains ranged from 0.6 to 6.2 cases per hundred thousand mice. The 56 cases studied had soft, raised masses that arose on the dorsal midline, primarily above the sutures of the skull. The lesions were prominent on gross examination due to abnormally long hair, change in direction of the hairs, and a change in hair color compared to the normal pelage.

Microscopically, the masses consisted of normal adipose tissue in the reticular dermis and subcutis that sometimes extended through the cranial sutures, entering the brain, or expanding into the ventricles. Large masses occasionally contained normal appearing thyroid, intestine, respiratory epithelium lined cysts, squamous epithelial cysts, bone and marrow, cartilage, glands, and angiomatous anomalies. In all cases, the epidermis was intact. Hair follicles were larger in the affected areas of many cases compared to those in adjacent skin.

Breeding studies did not yield affected offspring, indicating this is a congenital, noninherited abnormality. This condition resembles “lipomatous” hamartomas, a congenital defect in human beings.
In Vitro Cytopathogenicity and In Vivo Virulence of Two Strains of Canine Parainfluenza Virus
Authors: Baumgärtner W. , Krakowka S. , Durchfeld B.
Published: March 2010

In vivo and in vitro properties of two strains of canine parainfluenza virus(CPIV) were investigated. One strain, designated CPIV(+), induced syncytial giant cell formation and cytolysis in vitro, whereas the second strain, CPIV(−), caused only a mild strand-forming cytopathic effect with few, small syncytial giant cells. Vero cells infected with CPIV(+)or CPIV(−)were 100% positive for CPIV antigen as determined by immunofluorescent staining; however, 100% of CPIV(+)and less than 10% of CPIV(−)infected cells were hemadsorption positive. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis analysis revealed no differences in electrophoretic mobility of viral polypeptides between both strains; however, in CPIV(−)reduced or absent synthesis of the putative HN and F1proteins was observed. Isopyenic separation of CPIV(+)progeny virions showed a high proportion of viral particles with a buoyant density of 1.18 g/cm3. In contrast, CPIV(−)progeny virions had a heterogeneous density profile ranging from 1.08 to 1.18 g/cm3. Intracerebral infection of six ferrets with CPIV(+)resulted in moderate lymphocytic and histiocytic choroiditis, meningitis, and ependymitis, whereas CPIV(−)infection caused only mild to moderate inflammation. Immunohistologically, CPIV antigen was prominent in ependymal lining cells of the ventricles in CPIV(+)-infected ferrets and was reduced or lacking in CPIV(−)-infected ferrets ( n = 6). Sham-injected ferrets ( n = 6) did not have histologic lesions and no viral antigen was identified. The present findings suggest that certain changes in the activities of CPIV glycoproteins may lead to alterations of CPIV virulence in vivo.
Neutrophil Function in Dogs with Congenital Ciliary Dyskinesia
Authors: Maddux J. M. , Edwards D. F. , Barnhill M. A. , Sanders W. L.
Published: March 2010

In vitro neutrophil function was assessed in two English Springer Spaniel dogs, two Bichon Frise dogs, and one Chow Chow dog with congenital ciliary dyskinesia; three clinically normal English Springer Spaniel dogs that were presumed heterozygous for congenital ciliary dyskinesia; and five control dogs. Chemotaxis and random migration in affected and heterozygous dogs were found to be comparable to those of control dogs. Increased ( P ≤ 0.05) neutrophil adhesion, antibody dependent cell-mediated cytotoxicity, iodination of proteins, and oxygen radical production in neutrophils from a affected dogs were probably the result of chronic bacterial infection in vivo. Bacterial ingestion by neutrophils from the three heterozygous English Springer Spaniel dogs was significantly increased compared to control dogs but was not different from affected English Springer Spaniel dogs, suggesting a breed-related phenomenon. Significant decreases in neutrophil function were not seen in any of the dogs with congenital ciliary dyskinesia, indicating that a defective microtubular system is not shared by respiratory cilia and neutrophils and that defective neutrophil function does not contribute to respiratory infection.
Congenital and Acquired Melanocytomas (Benign Melanomas) in Eighteen Young Horses
Authors: Foley G. L. , Valentine B. A. , Kincaid A. L.
Published: March 2010

In a retrospective study, cutaneous melanocytic tumors from 18 horses, less than 2 years old, were examined histopathologically and clinical follow-up requested. Melanocytomas (benign melanomas) occurred in a variety of breeds and in horses of varied coat color. The age of the horses at the time of biopsy ranged from 3 weeks old to 2 years old. Four melanocytomas were congenital, 11 melanocytomas were acquired by 1 year of age, and three were acquired prior to 2 years of age. Of the 18 horses, five were male, and 13 were female. All tumors were solitary and located on the legs or trunk; none were in the perineal region. Ulceration of the overlying epidermis was common. Tumors were generally localized and were not encapsulated. The tumors had a variety of cell patterns ranging from sheets, to streams, or nests of melanocytes. Cellular morphologic findings also ranged from epithelioid, to a mixture of epithelioid and spindle cells or to a spindle pattern. The nuclei were large and euchromatic, especially in the epithelioid cells. Several tumors had moderate cellular pleomorphism and binucleate cells. Mitotic activity was generally low (less than 1/high-powered field), but was readily detected (1–2/high-powered field) in bleached sections of four cases. Melanin pigmentation varied from mild to heavy. Melanophages were admixed with the tumor cells or in the adjacent tissue. Follow-up information was obtained on 15/18 horses and revealed that 14/15 horses were free of recurrence following excision. One neoplasm, that was poorly demarcated and had a spindle cell pattern, was not completely resected and continued to grow. These melanocytic tumors in young horses are distinct from melanomas in aged horses in their location, epithelial involvement, and age of horses affected. The majority of these tumors appear to be benign and share features of melanocytic nevi of human beings.
Spontaneous Fibro-osseous Proliferative Lesions in the Sternums and Femurs of B6C3F1 Mice
Authors: Albassam M. A. , Wojcinski Z. W. , Barsoum N. J. , Smith G. S.
Published: March 2010

Bone morphology associated with fibro-osseous proliferation in the femurs and sternums of 98 female B6C3F1 mice were compared morphologically and quantitatively to femurs and sternums from 100 male B6C3F1 and 79 CF1 mice (48 female and 31 male). In addition, sternal samples from five B6C3F1 mice per sex were collected and processed for electron microscopy. Fibro-osseous proliferation was present in female B6C3F1 mice, but not male B6C3FI or female CF1 mice. In female B6C3F1 mice at 32 weeks of age, the marrow spaces in the region of the proximal and distal epiphyseal plate were lined by large osteoblasts and had large vascularized centers. At 58 weeks, metaphyseal fibrovascular proliferative areas containing multinucleated cells and new cancellous bone delineating the lesion were seen. At 84 weeks, fibro-osseous tissue occupied the outer third of the sternal marrow cavity and by 110 weeks, more than two thirds of the marrow cavity. Fibroosseous proliferation was present in 100 and 94% of the examined sternums and femurs, respectively, of female B6C3F1 mice at 110 weeks of age, but not in male B6C3F1 or female CF1 mice. Ultrastructural examination of the sternal changes at 110 weeks showed numerous osteoblasts, irregular bony spicules, and fibrocyte-like cells. By morphometry, the normal marrow cavity in B6C3F1 females occupied 35% of a longitudinal section of the whole sternebra compared with 70% and 75% of the whole sternebra in B6C3F1 males and CF1 female, respectively. The area of the whole sternum in B6C3F1 females did not change despite extensive fibro-osseous proliferation. The bony changes were associated with significant increase in plasma alkaline phosphatase activity. A comparable incidence of cystic endometrial hyperplasia and cystic ovaries were seen in both B6C3F1 and CF1 females. The results of this study suggest that B6C3F1 females may be more sensitive than females of other strains to age-related hormonal changes that alter the bone microenvironment.
Cutaneous Neoplasia in 340 Cats
Authors: Miller M. A. , Nelson S. L. , Turk J. R. , Pace L. W. , Brown T. P. , Shaw D. P. , Fischer J. R. , Gosser H. S.
Published: March 2010

A total of 340 cases of cutaneous neoplasia were diagnosed in 340 of 3,564 cats that were examined by biopsy or necropsy during a 41-month period from January 1, 1986 through May 31, 1989. Eighteen types of tumor occurred, but four types comprised 77% of the cases. These were basal cell tumor, 89 cases (26%, mean age 10.3); mast cell tumor, 72 cases (21%, mean age 8.6); squamous cell carcinoma, 52 cases (15%, mean age 11.6); and fibrosarcoma, 50 cases (15%, mean age 10.2). For each of these four types of tumors, peak number of cases occurred in cats older than 10 years. Mast cell tumor was the only tumor diagnosed in cats younger than 1 year. The head was the most common site for basal cell tumors, mast cell tumors, and squamous cell carcinomas. The legs were the most common location of fibrosarcomas. Siamese cats had approximately three times as many mast cell tumors as statistically expected, but only one-fourth as many squamous cell carcinomas. Breed predilection for other skin tumors was not apparent. Sex predilection was not detected for any skin tumor.
Distinctive Unclassified Mesenchymal Tumor of the Digit of Dogs
Authors: Carpenter J. L. , Dayal Y. , King N. W. , Moore F. M.
Published: March 2010

Four examples of a mesenchymal tumor of undetermined histogenesis occurred in three mixed-breed dogs and one Yorkshire terrier. All tumors occurred as solitary, soft to firm, solid, tan, and ulcerated masses in the digits of dogs aged 11 to 15 years. The compact cellular tumor had cells with anisokaryotic round, oval, or irregular nuclei, some of which were multinucleated. The neoplastic cells appeared to arise in the tissue near the third phalanx in the area of dense collagenous trabeculae located proximal to the fat pad and sweat glands. The unclassifiable cells had some features of histiocytes by transmission electron microscopy, but failed to stain for lysozyme and alpha-1-antichymotrypsin, markers for monocyte-macrophage derived cells. Immunohistochemically, the cells stained for vimentin but not for cytokeratins, desmin, S-100 protein, epithelial membrane antigen, alpha-lactalbumin, lysozyme, alpha-1-antichymotrypsin, alpha-lactalbumin, casein, and heavy and light chain immunoglobulins. The combined findings of light and transmission electron microscopy and immunohistochemistry exclude tumor histogenesis from an epithelial cell, melanocyte, mast cell, plasma cell, Schwann cells, and Merkel cell.
T and B Lymphocyte Subsets in Spermatic Granulomas in Five Rams
Authors: Saravanamuthu V. , Foster R. A. , Ladds P. W. , Gorrell M. D.
Published: March 2010

Epididymal spermatic granulomas from five adult (>4 years old) rams from a commercial flock were evaluated by quantitative histologic methods. Sections were stained for isotype specific immunoglobulin (Ig)-containing cells or specific lymphocyte subsets, as indicated by plasma membrane staining with monoclonal antibodies (MoAb). For the purpose of analysis, individual spermatic granulomas were allocated to one of three groups (early, resolving, or intermediate) on the basis of histologic examination. Ig-containing cells were most prevalent in early spermatic granulomas, and IgG-containing cells predominated in all spermatic granulomas regardless of their presumed age. IgM immunoglobulin-containing cells were the next in prevalence, and IgA-containing cells were infrequent. Assessment of lymphocyte subsets confirmed that lymphocytes present were of both T- and B-cell lineage and were well represented in all spermatic granulomas. CD4+ (MHC Class II—restricted “helper”) T-cells were more prevalent in early spermatic granulomas than in intermediate or resolving types, while CD8+ (MHC Class I—restricted, “cytotoxic/suppressor”) T-cells were more prevalent in spermatic granulomas of the intermediate type. These results suggest that in addition to an essentially foreign body reaction to extravasated spermatozoa, both local production of antibody and accumulation of a variety of B- and T-lymphocytes are present in ovine spermatic granulomas.
Pathologic and Immunocytochemical Studies of Morbillivirus Infection in Striped Dolphins (Stenella coeruleoalba)
Authors: Domingo M. , Visa J. , Pumarola M. , Marco A. J. , Ferrer L. , Rabanal R. , Kennedy S.
Published: March 2010

Hundreds of striped dolphins ( Stenella coeruleoalba) died along the Spanish Mediterranean coast during the second half of 1990. We necropsied 58 dolphins. Partial collapse of the lungs with patchy atelectasis, subcutaneous edema, icterus, and stomatitis were the most prominent gross morphologic changes. Histologically, a bronchiolo-interstitial pneumonia was the most frequent lesion (72% of the animals). It was characterized by hyperplasia of alveolar epithelial type II cells and formation of multinucleate syncytia in alveolar and bronchiolar lumina. Other prominent lesions were encephalitis (69%), lymphoid depletion, and formation of multinucleate syncytia in the cortex of lymph nodes. The distribution of morbillivirus antigen was investigated in 23 wellpreserved dolphins using a monoclonal antibody against the hemagglutinin glycoprotein of phocine distemper virus. Positive immunostaining was found in brain (77%), in lung (70%), and in mesenteric (61%), mediastinal (47%), and prescapular (45%) lymph nodes. Phocine distemper virus antigen was demonstrated less frequently in trachea, stomach, biliary epithelium, intestine, kidney, and mammary gland. Necrotizing-hemorrhagic pneumonia and encephalitis due to Aspergillus fumigatus were seen in three dolphins, whereas two animals had lesions of toxoplasmosis. Changes in our dolphins were similar to those caused by distemper in seals and porpoises. The origin of the dolphin virus and the relationships among dolphin, seal, and porpoise morbilliviruses are unknown.
A Light and Electron Microscopic Study of Changes in Blood and Bone Marrow in Acute HemorrhagicTrypanosoma vivaxInfection in Calves
Authors: Anosa V. O. , Logan-Henfrey L. L. , Shaw M. K.
Published: March 2010

Eleven 6-month-old calves were tsetse fly challenged with a stock of Trypanosoma vivax (IL 2337) that causes hemorrhagic infection. The calves were randomly euthanatized every 4 to 6 days; two other calves served as controls. Peripheral blood changes included anemia, thrombocytopenia, and an initial leukopenia. Later in the course of infection, leukocytosis associated with lymphocytosis and neutropenia developed. Moderate reticulocytosis (highest mean count 3.6 ± 3.7%, maximum count 9.4%) accompanied the first wave of parasitemia, but poor response (highest mean 0.4 ± 0.0%) occurred during the second wave, despite the persistence of severe anemia. Light microscopic examination of bone marrow samples showed a drop in the myeloid: erythroid ratio with a decrease in granulocytes, particularly metamyelocytes, bands, and segmenters. Increase in lymphocyte counts corresponded with the appearance of lymphoid nodules within the marrow. Megakaryocyte volume increased significantly in infected animals, and some megakaryocytes showed emperipolesis of red cells, neutrophils, and lymphocytes. Transmission electron microscopic examination of the bone marrow revealed that trypanosomes had crossed the sinusoidal endothelium into the hematopoietic compartment as early as the second day of parasitemia. Macrophages proliferated in the bone marrow; and from the second day of parasitemia until the end of the experimental infection, on day 46, the macrophages had phagocytosed normoblasts, eosinophil and neutrophil myelocytes, metamyelocytes, bands, and segmenters, as well as reticulocytes, erythrocytes, and thrombocytes. Therefore, dyserythropoiesis and dysgranulocytopoiesis were responsible, in part, for the observed anemia and granulocytopenia, respectively.
Effect of Zearalenone on Days 7 to 10 Post-mating on Blastocyst Development and Endometrial Morphology in Sows
Authors: Long G. G. , Turek J. , Diekman M. A. , Scheidt A. B.
Published: March 2010

First litter sows in naturally occurring post-weaning estrus were hand mated to proven boars and were fed a diet supplemented with zearalenone, an estrogenic mycotoxin (1 mg zearalenone/kg body weight), or a control diet on days 7 through 10 after mating. Embryos (blastocysts) and endometrial biopsies were collected from control and treated sows on days 9, 11, and 13 after mating. All blastocysts harvested on day 9 were spherical; treatment of sows with zearalenone had no effect on blastocyst development. Blastocysts collected from treated sows on day 11 were in stages of elongation comparable to those of blastocysts from control sows but had mild degenerative changes in the embryonic disks, characterized by slightly retarded development and an increase in the number of necrotic cells. Blastocysts collected from treated sows on day 13 were in an advanced stage of degeneration, characterized by circumferential constrictive division, fragmentation, and degeneration and disorganization of the embryonic disk. Feeding zearalenone to pregnant sows had no effect on the normal decrease in height of the endometrial luminal epithelium on days 9 through 13 after mating and no effect on morphologic appearance of secretory vesicles in the endometrial glandular epithelium. The dosage scheme of zearalenone used in this study did not cause any morphologic changes in the endometrium that could be associated with hyperestrogenism.
Acute Airsacculitis in Untreated and Cyclophosphamide-pretreated Broiler Chickens Inoculated withEscherichia coliorEscherichia coliCell-free Culture Filtrate
Authors: DeRosa M. , Ficken M. D. , Barnes H. J.
Published: March 2010

Ninety commercial broiler chickens were divided into three equal groups; 30 were injected with brain-heart-infusion broth into the cranial thoracic air sacs (controls), 30 were similarly inoculated with a culture of Escherichia coli, and 30 were similarly inoculated with E. coli cell-free culture filtrate. Birds were examined from 0 to 6 hours post-inoculation. E. coli-inoculated and cell-free culture filtrate-inoculated chickens reacted similarly, with exudation of heterophils into the air sac. Microscopically, heterophils were present in low numbers perivascularly 0.5 hour after inoculation and became more numerous by 3 hours post-inoculation. By 6 hours post-inoculation, there was severe swelling of air sac epithelial cells and thickening of the air sac by proteinaceous fluid and heterophils. Ultrastructurally, air sac epithelial cells were swollen and vacuolated, and interdigitating processes were separated. Histologically and ultrastructurally, all features in control chickens were normal, with only rare heterophils in the air sac interstitium. In E. coli-inoculated and cell-free culture filtrate-inoculated chickens, cell counts (predominantly heterophils) in air sac lavage fluids increased markedly at 3 and 6 hours, with only slight increases in counts from lavages of controls. Heteropenia was observed in E. coli-inoculated chickens, whereas heterophilia was observed in cell-free filtrate chickens and controls. Ninety additional chickens were pretreated with cyclophosphamide, subdivided into three equal groups, and inoculated and examined similarly as above. Cyclophosphamide pretreatment reduced inflammatory changes in air sacs, lowered cell numbers in lavage fluids, and abolished hematologic changes; however, it did not prevent epithelial cell changes. These results indicate that cell-free culture filtrate of E. coli induces changes similar to those induced by cultures of E. coli.
Histopathologic and Ultrastructural Myocardial Alterations in Calves Deficient in Vitamin E and Selenium and Fed Polyunsaturated Fatty Acids
Authors: Kennedy S. , Rice D. A.
Published: March 2010

We developed an experimental model of nutritional degenerative myopathy in ruminant cattle. Fourteen experimental calves were fed a diet low in vitamin E and selenium for 127 to 137 days. Six of these calves were then euthanatized. After 127 days, a dietary additive of linseed oil that had been treated to protect it against ruminal hydrogenation was added to the low vitamin E and selenium diet of the eight remaining calves as a source of polyunsaturated fatty acids. Six of these animals were euthanatized after 6 to 11 days of polyunsaturated fatty acid feeding; the other two died after 6 and 8 days. Macroscopic myocardial alterations were seen in five polyunsaturated fatty acid-fed calves but not in any other experimental calf. Microscopic lesions, comprising multifocal or diffuse cardiocyte degeneration and necrosis, were seen in atrial and ventricular myocardium of all experimental calves. These changes were more severe in polyunsaturated fatty acid-fed calves than in animals that did not receive polyunsaturates. Ultrastructurally, sublethally damaged cardiocytes had lysed contractile material; vacuolated sarcoplasm; altered mitochondria, sarcoplasmic myelin figures, and lipofuscin granules; and multiple nuclei. Necrotic cardiocytes had contracted myofibrils, pyknotic nuclei, mineralized mitochondria, and plasmalemmal disruption; the external lamina remained largely intact. Necrosis was followed by macrophage invasion and phagocytosis of necrotic debris. Repair of the lesions was by deposition of collagen and elastin fibers. No alterations were seen in the hearts of control calves fed vitamin E and selenium-supplemented diet. The induced myocardial lesions are similar to those of spontaneous nutritional degenerative myopathy in ruminant cattle.
Langerhans' Cells in Equine Cutaneous Papillomas and Normal Skin
Authors: Hamada M. , Takechi M. , Itakura C.
Published: March 2010

Langerhans' cells (LC) were investigated immunohistochemically and electron microscopically in normal equine epidermis and 133 equine cutaneous papillomas experimentally induced in five 2-year-old Thoroughbred horses. Class II major histocompatibility complex antigen-positive dendritic LC were found in the normal epidermis and ultrastructurally had the characteristic Birbeck's granules. In the developing phase of the papillomas, LC were significantly decreased in number and size, indicative of a hypofunctional state. In the regressing phase of the papillomas, LC were markedly increased in number, especially at the epidermis-dermis junction. LC with long dendrites were rich in cytoplasm with well-developed cytoplasmic organelles, including Golgi apparatus, lysosomes, Birbeck's granules, and multivesicular bodies. These LC were hyperfunctional. An infiltration of many T lymphocytes was also observed at the epidermis-dermis junction.