bluuebunny/crossref_metadata_2025 huggingface dataset:
Depletion of Salivary Gland Epidermal Growth Factor by Sialodacryoadenitis Virus Infection in the Wistar Rat
Authors: Percy D. H. , Hayes M. A. , Kocal T. E. , Wojcinski Z. W.
Published: January 2010

Male and female Wistar rats 2 to 15 months of age were inoculated intranasally with sialodacryoadenitis (SDA) virus and killed at 8 to 21 days post-inoculation (PI). Submandibular glands were evaluated by light and electron microscopy, and levels of salivary gland epidermal growth factor (EGF) were quantitated by cytochemistry and competitive radioreceptor assay. Apical granules in the epithelial cells of the granular convoluted tubules (GCT) were selectively depleted during the acute and convalescent stages of the disease. In addition, levels of immunoreactive EGF were reduced in affected submandibular glands, especially at 8 to 14 days PI with SDA virus, but some evidence of EGF depletion was seen at up to 3 weeks PI. A corresponding transient depletion of EGF receptor reactive salivary EGF was seen between 1 and 3 weeks after experimental SDA infection. These studies suggest that a clinical (or subclinical) infection with SDA virus could have significant effects on experimental studies on EGF-dependent functions, including reproductive physiology and carcinogenesis.
Comparison in Gnotobiotic Pigs of Lesions Caused by Verotoxigenic and Non-verotoxigenic Escherichia coli
Authors: Hall G. A. , Chanter N. , Bland A. P.
Published: January 2010

To compare the pathogenesis of calf and rabbit strains of E. coli. gnotobiotic pigs were infected with 1010 colony forming units (cfu) of verotoxigenic strain RDEC-1 or S102-9, or a non-verotoxigenic E. coli (X114/83). Pigs were killed 4 days later, and intestinal tissue was fixed and examined by light, scanning, and transmission electron microscopy. Strains S102-9 and RDEC-1 caused diarrhea, attached to enterocytes, and effaced microvilli, confirming that the calf and rabbit strains possessed similar mechanisms of pathogenicity. Non-verotoxigenic strain X114/83 did not cause diarrhea, but in 5/5 piglets it was detected in histological sections adherent to enterocyte surfaces. Exfoliated enterocytes were seen in 4/5. Bacteria attached to enterocytes by “cups” and “pedestals,” with effacement of microvilli, were seen by electron microscopy in 1/5 piglets. It was concluded that strain S102-9 appears to be an animal equivalent of human enterohemorrhagic E. coli. that verotoxin is not essential in the pathogenesis of attaching and effacing lesions, and that the lesions induced by S102-9 are more severe in gnotobiotic pigs than in gnotobiotic or conventional calves.
Cephalosporin-induced Changes in the Ultrastructure of Canine Bone Marrow
Authors: Deldar A. , Lewis H. , Bloom J. , Weiss L.
Published: January 2010

Fourteen healthy dogs were given 540 to 840 mg/kg of cefazedone (Refosporen®) intravenously for up to 4 months or until peripheral blood cell counts were depressed. Within 6 to 10 weeks treated dogs developed pancytopenia (5/14), thrombocytopenia (11/14), moderate to severe neutropenia (8/14), and/or normocytic anemia with erythroblastemia (8/14). Ultrastructural changes in bone marrow of severely cytopenic dogs included mitochondrial damage in hematopoietic and nonhematopoietic cells, thickening of endosteal bone lining layers, increased adventitial coverage of vascular sinuses, and an increased number of active macrophages. Swollen, ruptured mitochondria were in erythroid, granulocytic, and megakaryocyte cells, and, to a lesser extent, in macrophages, reticular endothelial, and bone lining cells. Maturation arrest was evident in both erythroid and granulocytic cell lines. There was also evidence of ineffective erythropoiesis and granulopoiesis. None of these changes were observed in bone marrow of controls, treated dogs that did not develop cytopenia, or dogs allowed to recover after cessation of dosing.
Birefringent Spores Differentiate Encephalitozoon and Other Microsporidia from Coccidia
Authors: Tiner J. D.
Published: January 2010

Tissue sections containing protozoa with birefringent spores indicate an infection by microsporidia. Hematoxylin and cosin (HE) does not affect spore birefringence, but some special stains (Goodpasture, Brown and Brenn, or Gram) obscure it. Encephalitozoon cuniculi from an infected puppy, Glugea stephani from the winter flounder Pseudopleuronectes americanus. and Plistophora sp. from the Japanese eel Anguilla japonica all have birefringent spores. Encephalitozoon was studied first and then the two genera from fishes were included for comparison. Small masses of newly formed spores (pseudocysts) line Glugea cysts and then merge into the contents of the cyst as it enlarges and bulges through the intestinal musculature to become subserosal. The birefringence of Plistophora is present in fully mature spores contained in pseudocysts, but may disappear when the spores are released and become involved in granulomas. Coccidians from various hosts were always non-birefringent. Whenever a protozoan organism in a tissue could be either microsporidian or coccidian, a test for birefringence, if positive, resolves the question. There may be no need to use a special stain.
Anti-rat Myoglobin Antisera in the Immunocytochemical Diagnosis of Rhabdomyosarcomas of Rats
Authors: Takahashi K. , Maita K. , Shirasu Y. , Taniguchi H. , Yoshikawa Y.
Published: January 2010

Anti-rat myoglobin (Mb) was prepared and used in the avidin-biotin-peroxidase complex (ABC) method on paraffin-embedded sections of nine soft tissue tumors (including two rhabdomyosarcomas) of rats. Distribution and nature of the reactive substance to Mb antiserum were compared to those of desmin antiserum. Rat Mb was isolated from the skeletal muscle; monospecificity of the rat antiserum was confirmed by the immunoblotting procedures. The Mb antiserum reacted specifically to normal and neoplastic striated muscle cells. Mb-staining reactions were present diffusely in the cytoplasm, while desmin-staining substances were localized at Z-bands or were diffuse in the cytoplasm as separated aggregates. Reaction to the Mb serum was also detected in cells of thick portions of Henle's loop and distal convoluted tubules.
Neutrophil-induced Erythrocyte Injury: A Potential Cause of Erythrocyte Destruction in the Anemia Associated with Inflammatory Disease
Authors: Weiss D. J. , Klausner J. S.
Published: January 2010

Activated neutrophils at effector/target ratios of 1:20 to 1:2,000 induced depletion of red blood cell (RBC)-reduced glutathione, increased membrane-bound hemoglobin and methemoglobin, and promoted immunoglobulin binding to the cell membrane. Superoxide dismutase/catalase ameliorated the decrease in reduced glutathione and the increase in methemoglobin and immunoglobulin binding. This is interpreted as evidence that activated neutrophils can alter the antigenic nature of the RBC membrane through generation of toxic oxygen radicals.
Necropsy Findings in Rhesus Monkeys Experimentally Infected with Cultured Simian Immunodeficiency Virus (SIV)/Delta
Authors: Baskin G. B. , Murphey-Corb M. , Watson E. A. , Martin L. N.
Published: January 2010

Lesions induced in rhesus monkeys by different isolates of simian immunodeficiency virus (SIV)/Delta were studied at necropsy. Four groups of monkeys were inoculated with SIV/Delta isolated from other experimentally infected rhesus monkeys, while one group was inoculated with SIV/Delta from an asymptomatic mangabey monkey. Three rhesus isolates and the mangabey isolate were virulent, killing 75–100% of infected monkeys. One rhesus isolate, which had been extensively passaged in vitro, was attenuated but was restored to virulence by single animal passage. Clinically, infected monkeys had lymphadenopathy, splenomegaly, diarrhea, and a rash. Most monkeys died of enteric disease. The following lesions were seen: weight loss, thymic atrophy, lymphoid atrophy, bone marrow hyperplasia, encephalitis, colitis, amyloidosis, hepatitis, glomerulosclerosis, and the presence of syncytial cells. One Rh Epstein-Barr virus (EBV)-related lymphoma occurred. Opportunistic agents were identified: cytomegalovirus, adenovirus, Cryptosporidia, and Pneumocystis. Shigella and Campylobacter often caused colitis.
Cardiovascular Complications of Chronic Catheterization of the Jugular Vein in the Dog
Authors: Mesfin G. M. , Higgins M. J. , Brown W. P. , Rosnick D.
Published: January 2010

Cardiovascular changes associated with indwelling catheters were evaluated in 51 adult beagle dogs catheterized for 4 to 9 weeks. Pathologic changes consistent with traumatic injury were in the vena cava and endocardium of the right atrium of 88% of cannulated dogs. Lesions were characterized by surface denudation and diffuse intimal thickening due to myointimal hyperplasia and deposition of extracellular matrix. Affected intima was lined by hyperplastic, poorly differentiated endothelial cells and contained round to oval cells with characteristics of smooth muscle cells. After 9 weeks, thickened intima was vascularized and composed of spindle-shaped cells and fibrillar stroma. Intimal sclerosis and localized proliferative papillary projections in the vena cava cranial to areas of myointimal hyperplasia occurred infrequently. Traumatic lesions, regardless of location or severity, did not extend below the internal elastic membrane. Inflammatory cellular responses, when present, were minimal. The location, distribution, and morphogenesis of catheter-related cardiovascular lesions distinguishes them from those induced by chemical toxicity or pharmacotoxicity.
Gut-associated Lymphoid Tissue in the Large Intestine of Calves. II. Electron Microscopy
Authors: Liebler E. M. , Pohlenz J. F. , Cheville N. F.
Published: January 2010

Scanning electron microscopy of lymphoid tissue in the large intestine of three germfree calves (age 3, 6, and 7 days) revealed two different units: propria nodules and lymphoglandular complexes (LGC). Propria nodules had lymphoid tissue predominantly in lamina propria and were covered by distinct follicle-associated epithelium which lacked goblet cells; nodules were surrounded by wide crypts, which were also lined by follicle-associated epithelium towards the luminal side. Lymphoglandular complexes had lymphoid follicles in the tunica submucosa; epithelial diverticulae extended through the muscularis mucosae branching into the lymphoid nodule. In centers of lymphoglandular complexes, protrusions of lymphoid tissue were covered with distinct follicle-associated epithelium. By transmission electron microscopy cells compatible with M cells in the small intestine of calves and cells with characteristics of both enteroabsorptive and M cells were found. Follicle-associated epithelium of propria nodules and lymphoglandular complexes differed only in the relative frequency of cell types.
Pathological Lesions in the Lungs of Ducks Infected with Influenza A Viruses
Authors: Cooley A. J. , Van Campen H. , Philpott M. S. , Easterday B. C. , Hinshaw V. S.
Published: January 2010

To determine histopathological damage in the respiratory tract, ducks were inoculated with five different influenza A viruses, including viruses virulent for other avian hosts. Lungs were collected for detection of virus and histopathological examination. Small amounts of infectious virus were recovered from lungs, and viral antigens were demonstrated by immunoperoxidase staining with monoclonal antibodies to the viral nucleoprotein. Although clinical signs were not detected, lungs of ducks infected with both virulent and avirulent viruses had mild pneumonia characterized by infiltrates of lymphocytes and macrophages. These findings show that although clinical signs are not evident, ducks may have damage to the respiratory tract during influenza.
Increased Levels of DNA Synthesis in Hyperplastic Renal Tubules of Aging Nephropathy in Female F344/NCr Rats
Authors: Konishi N. , Ward J. M.
Published: January 2010

Histoautoradiography was done to evaluate cell turnover by measuring levels of DNA synthesis in the different anatomic areas of the kidney in aging (76 to 103 weeks of age) female F344/NCr rats after injection of tritiated thymidine (3H-thymidine). All areas showed increased 3H-thymidine labeling indices (LI), including cortical and medullary tubules and interstitium. The extent of increase was directly correlated with increasing severity of the nephropathy. Atrophic, degenerative, and hyperplastic cortical tubules in areas of nephropathy had LI eight to nine times greater than nonaffected areas and more normal kidneys. These observations suggest that the hyperplastic responses of renal tubules to the unknown etiologic agents of aging nephropathy may be similar to those of tubules responding to chemical toxins.
Experimental Encephalomyocarditis Virus Infection in Mongolian Gerbils (Meriones unguiculatus)
Authors: Matsuzaki H. , Doi K. , Mitsuoka T. , Tsuda T. , Onodera T.
Published: January 2010

Two strains of Mongolian gerbils ( Meriones unguiculatus), Tumble Brook (TUM) and Japan Medical Science (JMS), were intraperitoneally inoculated with the D variant of encephalomyocarditis virus (EMC-D) and killed 3 days later. Mortality was significantly higher in females than in males. Evidence of viral replication was detected in the heart of both strains and in the pancreas of the TUM strain. Histopathological alterations were found in the heart and pancreas. Heart lesions involved foci of necrosis with inflammatory cell infiltration and calcification in both strains. Pancreatic lesions were restricted to the exocrine glands; islets of Langerhans were rarely and secondarily involved in the extensive destruction of exocrine glands. Severe acinar cell necrosis with marked inflammatory edema was conspicuous in TUM, whereas only slight acinar cell involvement was detected in JMS gerbils. Immunoperoxidase staining showed viral antigens in intracytoplasmic vacuoles in damaged acinar cells.
Acute and Persistent Alterations in Pulmonary Inflammatory Cells and Airway Mast Cells Induced by Sendai Virus Infection in Neonatal Rats
Authors: Castleman W. L. , Owens S. B. , Brundage-Anguish L. J.
Published: January 2010

Neonatal rats inoculated with parainfluenza type 1 (Sendai) virus develop alveolar dysplasia and bronchiolar hypoplasia by 30 to 110 days after inoculation. Weanling rats do not develop these abnormalities. Because neonatal animals have hyporesponsive immune and inflammatory cell functions, and because neonatal rats support pulmonary viral replication for longer duration and are delayed in their viral antibody response compared to weanling rats, we compared inflammatory and immune responses of two age groups of rats following viral inoculation. Data from quantitative bronchoalveolar lavage 1 to 29 days following viral inoculation demonstrated that neonates had significantly fewer ( P < 0.05) lymphocytes and macrophages in their bronchoalveolar fluid per cm2alveolar surface than weanlings. Magnitude of neutrophil responses in neonatal rats compared to weanlings were not depressed. Pulmonary interferon activity was lower in neonates than in weanlings at 2, 3, 4, and 5 days after viral inoculation. Neonates failed to make antibody following intraperitoneal inoculation of inactivated viral antigen, whereas weanling rats had detectable viral antibody by 3 to 5 days after injection of antigen. At 90 days after inoculation of neonates, viral-inoculated rats had over 100-fold greater numbers ( P < 0.05) of mast cells in enzyme-dissociated lung preparations compared to age-matched controls. Viral-inoculated rats had two- to three-fold greater densities of mast cells (#/mm) in bronchiolar walls ( P < 0.02) than did control rats. We conclude that the enhanced susceptibility of neonatal rats as compared to weanling rats to Sendai virus-induced abnormalities in alveolar and bronchiolar growth is associated with a less intense pulmonary lymphocytic inflammatory cell response as well as a less effective antibody and interferon response to viral infection. Neonatal viral infection also induces persistent increases in airway mast cells that might be important in the pathogenesis of viral-induced airway hyperreactivity.
Ovine Arthrogryposis and Central Nervous System Malformations Associated with in utero Cache Valley Virus Infection: Spontaneous Disease
Authors: Edwards J. F. , Livingston C. W. , Chung S. I. , Collisson E. C.
Published: January 2010

Gross appearance and histologic lesions seen in 15 newborn lambs in an outbreak of congenital arthrogryposis with hydrocephalus or hydranencephaly (CAH) in Texas are described. Severe arthrogryposis with skeletal muscle hypoplasia was seen in limbs of affected lambs. Spinal column deformities were also present. Multiple central nervous system (CNS) malformations were present in CAH lambs including micrencephaly, cerebellar hypoplasia, micromelia, hydrocephalus, hydranencephaly, and porencephaly. Histologic lesions consisted primarily of areas of necrosis and loss of the paraventricular neuropil and motor neurons in the CNS and a resolving myositis with poorly developed myotubular myocytes in skeletal muscle. Seroepidemiologic studies on the flock and serologic data from heart blood taken from the stillborn affected lambs indicated that the outbreak was due to in utero infection with Cache Valley Virus.
A Histologic and Immunocytochemical Study of Choroid Plexus Tumors of the Dog
Authors: Ribas J. L. , Mena H. , Braund K. G. , Sesterhenn I. A. , Toivio-Kinnucan M.
Published: January 2010

Sixteen choroid plexus (CP) tumors in 12 male and four female adult dogs were analyzed microscopically. Tumors were in the lateral (six), third (six), and fourth (four) ventricles. The average age of the dogs was 6 years. Tumors were classified by the following criteria: 1) choroid plexus papilloma (CPP), which resembled normal choroid plexus and had low mitotic activity; 2) choroid plexus papilloma with atypical features (atypical CPP), which had increased cellular density, nuclear atypia, two to four mitoses per 40 × microscopic field, necrosis, and infiltration of the brain parenchyma and/or leptomeninges; and 3) choroid plexus carcinoma (CPC), which had marked nuclear atypia, poorly formed papillae, >four mitoses per 40 × microscopic field, abnormal mitotic figures, and/or extraneural metastasis. The 16 tumors were classified either as CPP or atypical CPP (none as CPC). Statistically significant associations between brain infiltration and necrosis and atypical CPP were identified. Immunohistochemical studies in 11 tumors demonstrated staining for keratin in three tumors, two of which also reacted with carcinoembryonic antigen (CEA). There was no immunoreactivity with glial fibrillary acidic protein or epithelial membrane antigen. Choroid plexus from one of three control dogs stained focally for cytokeratin only. It is concluded that normal choroid plexus and CP tumors in the dog express epithelial, but not glial differentiation.
Epididymal Interstitial (Leydig) Cell Tumors in B6C3F1 Mice
Authors: Mitsumori K. , Talley F. A. , Elwell M. R.
Published: January 2010

Six primary interstitial cell tumors of the epididymis were identified from 46,752 male B6C3F1 mice used in chronic toxicity and carcinogenicity studies. Five of the tumors occurred at the end of 2-year studies; none were attributed to treatment. None of the mice with epididymal tumors had a primary testicular tumor. Histologically, tumors were characterized by a nodular or diffuse proliferation of tumor cells in the epididymal interstitium. Most cells were polygonal with highly vacuolated cytoplasm (vacuolated cells) or eosinophilic cytoplasm (eosinophilic cells). Smaller hyperchromatic cells with scant basophilic cytoplasm (basophilic cells) and cells with yellow-brown pigment characteristic of lipofuscin (pigmented cells) were less common. In each tumor two or more cell types were present. Extension of these tumors through the capsule, invasion of the testis, or metastasis did not occur. By electron microscopy both eosinophilic and vacuolated cell types had a large round or oval nucleus with sparse heterochromatin, abundant mitochondria with tubulovesicular cristae, and frequent desmosome structures between cell membranes. Vacuolated cells contained numerous lipid droplets. Morphological features of the epididymal tumors are similar to those of the testicular interstitial (Leydig) cell tumor in mice and rats.
A Protein Toxin fromPasteurella multocidaType D Causes Acute and Chronic Hepatic Toxicity in Rats
Authors: Cheville N. F. , Rimler R. B.
Published: January 2010

Pasteurella toxin given subcutaneously to rats caused severe liver damage and growth suppression in doses as low as 15.6 ng. Toxin was lethal at and above 31.25 ng. Survival times were dose-dependent, and lesions differed with time of survival after toxin. Rats dead of acute toxicity had focal hepatic necrosis. Liver lesion were associated with diffuse endothelial damage, intravascular trapping of leukocytes, and degeneration of hepatocytes (characterized by glycogen depletion, development of vacuoles, and eosinophilic cytoplasmic inclusions). Endothelial cells, Kupffer cells, and macrophages had evidence of activation, e.g., increased cellular size with increases in Golgi vesicles, granules, and lysosomes. Rats with chronic toxicity (survival > 150 hr) had cirrhosis, intestinal villous atrophy, and markedly reduced body weight and fat. These data show that the rat is highly sensitive to toxins of Pasteurella multocida, and that even low doses of toxin cause liver injury and growth suppression.
Magnetic Resonance Imaging of Hepatic Neoplasms in the Rat
Authors: Johnson G. A. , Thompson M. B. , Cofer G. P. , Campen D. , Maronpot R. R.
Published: January 2010

Magnetic resonance imaging (MRI) at microscopic resolution was done on a live rat that had chemically induced hepatic neoplasms. Beginning at the anterior aspect of the liver, 16 contiguous transaxial slices (each 1.25 mm thick) were produced using three-dimensional Fourier transform sequences. The rat had been treated with diethylnitrosamine (200 mg/kg) at 70 days of age, and, subsequently, received periodic implants of 17a-ethynylestradiol for 60 weeks. Carr-Purcell-Meiboom-Gill (CPMG) sequences (repetition time = 2,000 and echo time = 20, 40, 60, 80 ms) were done to give quantitative measures of spin-spin relaxation times (T2). Pixel-by-pixel curve fitting from these multiple images yielded calculated T2 images. Histologic evaluation of three abnormal areas in the liver revealed solid and cystic hepatocellular adenomas. Although lesions were evident in early-echo images of the CPMG sequence, they were more apparent in the late-echo images. This was consistent with longer T2 relaxation times for the lesions. The voxels of dimensions (230 × 230 × 1,250 /μm) permitted resolution of volume elements <0.07 mm3. This in turn permitted clear delineation of focal lesions <3 mm in diameter. The potential for MRI at microscopic resolution in toxicologic research is clearly demonstrated.
Morphometric Evaluation of Rhesus Articular Cartilage: Correlation of Hexosamine and 35SO4= Incorporation
Authors: Roberts E. D. , Zeman D. H. , Miwa T. , Shoje H.
Published: January 2010

Morphometric evaluation of 20 rhesus articular cartilage samples were correlated with hexosamine and an 18–hour incorporation of 35SO4= as a measure of proteoglycan production on samples from the same joint. Reduced chondrocyte cellularity was the basis of the reduced maintenance of the matrix by the chondrocyte. In the more cellular cartilage, the matrix/lacunae area ratio was <25, and the less cellular group had a ratio of >40. An inverse correlation existed between morphometric cartilage matrix/lacunar area ratio and hexosamine content. A significant difference of 35SO4= incorporation was not seen between the three morphometric grades. Morphometric assessment reduces the subjectivity of articular cartilage evaluation.
Experimental Visceral Leishmaniasis in the Opossum
Authors: White M. R. , Chapman W. L. , Hanson W. L. , Latimer K. S. , Greene C. E.
Published: January 2010

Adult wild-trapped opossums were infected with Leishmania donovani (Khartoum strain, WR 378) and evaluated as an animal model of visceral leishmaniasis. All infected opossums died within 32 days. Loss of body fat, hepatomegaly, and petechiae of skin and abdominal musculature were seen at necropsy. Microscopically, numerous amastigote-laden macrophages were seen in histologic sections of liver, spleen, and lymph nodes; fewer parasite-laden macrophages were in the bronchial-associated lymphoid tissues and renal glomeruli. Hematological findings included thrombocytopenia (terminal), neutropenia, and lymphopenia. Blood lymphocyte blastogenesis in response to concanavalin A and phytohemagglutinin was decreased markedly at day 24 post-infection (PI). Serum antibodies (1:40 dilution) to promastigotes of L. donovani were detected in five of eight infected opossums tested on days 10 and 24 PI. Total bilirubin concentrations and alanine aminotransferase and aspartate aminotransferase activities were increased after day 25 PI. Activated partial thromboplastin times and one-stage prothrombin times were prolonged before death. Concurrently, factors V, VIII, and XII activities were decreased.
Spontaneous Nonthymic T Cell Lymphomas in Young Wistar Rats
Authors: Hayashi S. , Nonoyama T. , Miyajima H.
Published: January 2010

Spontaneous acute lymphomas and related leukemias, occurring in three of 2,974 male Wistar rats used as controls in toxicity studies during the last 14 years (1974–1987), were examined by light and electron microscopy and by using immunohistochemistry. At autopsy, conspicuous hepatosplenomegaly was noted. Morphologically, tumor cells of all three rats were medium-sized lymphocytes with many mitotic figures proliferating mainly in the spleen, liver, and bone marrow. Virus-like particles were not detected. Immunohistochemically, almost all tumor cells were positive for thy-1 antigen but negative for hematopoietic and differentiation markers such as W3/13, W3/25, OX4, OX8, and OX12. The results suggest that the lymphomas in these three rats were derived from T cells.
Emperipolesis of Hematopoietic Cells within Megakaryocytes in Bone Marrow of the Rat
Authors: Lee K. P.
Published: January 2010

Emperipolesis of hematopoietic cells within megakaryocytes was found in rats. The incidence was less than 0.3% in young rats (2 to 12 months old) but increased to 2–5% among the aging rats (18 to 24 months old). The incidence increased markedly in hyperplastic bone marrow secondary to chronic suppurative or neoplastic lesions. Mature neutrophils appeared to be the most common marrow cell engulfed by megakaryocytes. By light microscopy, engulfed cells were separated from megakaryocyte cytoplasm by a narrow pericellular space. By electron microscopy, marrow cells engulfed by megakaryocytes were located in the open canalicular system. Cell membranes of both engulfed cells and megakaryocytes were intact, and there was no fusion of cell membranes or phagosome formation in the megakaryocytes.
Histopathologic Findings and Energy Dispersive X-ray Spectroscopic Analysis of Experimentally Induced Foreign-body Pneumonias in Rats
Authors: Slocombe R. F. , Evans M. G. , Derksen F. J.
Published: January 2010

To document the diagnostic features of foreign-body pneumonias, four commonly used orally administered medicaments were instilled into the lungs of Sprague-Dawley rats. Rats in each group received a single 0.4 ml dose of either barium sulfate suspension (BaSO4), mineral oil, Pepto-bismol®, or Kaopectate® inoculated into a lung via a mainstem bronchus. The other lung served as a non-inoculated control. Rats were euthanatized on post-inoculation day 2 or 7 in order to document fully-developed, acute pulmonary lesions and developing, chronic pulmonary lesions, respectively. Light microscopic features of BaSO4-inoculated lungs were distinctive from changes in mineral oil-inoculated lungs at both post-inoculation days. On post-inoculation day 2, rats inoculated with BaSO4 had pneumonia characterized by large numbers of alveolar macrophages containing green-to-brown granular material. There was minimal interstitial involvement. On post-inoculation day 2, mineral oil caused pneumonia characterized by giant cells and alveolar macrophages that had cytoplasms distended with variably-sized clear vacuoles. Lungs inoculated with BaSO4 or mineral oil had changed little on post-inoculation day 7 compared to the light microscopic features observed on day 2. On post-inoculation day 2, rats inoculated with either Pepto-bismol® or Kaopectate® had broncho-interstitial pneumonia with areas of necrosis and hemorrhage. On post-inoculation day 7, lungs inoculated with Pepto-bismol® or Kaopectate® had extensive fibrosis within alveolar lumens. Energy dispersive spectroscopy performed on sections of lung from rats given BaSO4, Pepto-bismol®, and Kaopectate® yielded a unique elemental spectrum for each compound in situ on post-inoculation days 2 and 7. We conclude that pulmonary responses differ among these compounds and that energy dispersive spectroscopy is a useful diagnostic adjunct for the definitive identification of elements comprising BaSO4, Pepto-bismol®, and Kaopectate® in situ in affected lungs.
Immunohistochemical Localization of Chromogranin A in Normal Tissues from Laboratory Animals
Authors: Hawkins K. L. , Lloyd R. V. , Toy K. A.
Published: January 2010

To analyze the distribution of Chromogranin A in endocrine cells of various species of laboratory animals (dog, gerbil, guinea pig, hamster, monkey, mouse, and fetal, neonatal, and adult rats), normal tissues were stained immunohistochemically with polyclonal anti-bovine Chromogranin A antiserum (SP-1). Selected tissues (pituitary, adrenal, thyroid, parathyroid, pancreas, brain, peripheral nerve, stomach, small and large intestine, bone marrow, spleen, thymus, lymph node, and liver) from these species and from the rabbit were stained with two monoclonal anti-human Chromogranin A antibodies (LK2H10 and PHE5) to compare the immunoreactivities of the monoclonal antibodies and polyclonal antiserum. Staining with the polyclonal antiserum (SP-1) resulted in a broader spectrum of immunoreactivity but had more nonspecific background staining than either monoclonal antibody. Immunoreactivity and staining intensity with SP-1 varied between species, but most endocrine tissues (pituitary cells in the anterior and intermediate lobes, thyroid “C” cells, adrenal medulla, parathyroid, pancreatic islets, and enterochromaffin cells) from most species stained positively. In some species, pancreatic alpha cells stained more intensely, and two populations of adrenal medullary cells with different staining intensities were observed. Sciatic nerve (axonal area) was immunoreactive with monoclonal antibodies and/or the polyclonal antiserum in several species. The spectrum of immunoreactive tissues from fetal and neonatal rats increased with age. There was good cross-reactivity between species with SP-1, but not with either LK2H10 or PHE5. These results indicate that many endocrine cells with secretory granules in laboratory animals express Chromogranin A and that a polyclonal antiserum, such as SP-1, is more sensitive in detecting this protein in various species than monoclonal antibodies such as LK2H10 or PHE5.
Chlamydiosis in Mariculture-reared Green Sea Turtles (Chelonia mydas)
Authors: Homer B. L. , Jacobson E. R. , Schumacher J. , Scherba G.
Published: January 2010

From August 1990 to June 1991, a moderate die-off of 4- to 5-year-old green sea turtles ( Chelonia mydas) occurred at Cayman Turtle Farm, Grand Cayman, British West Indies. Clinical signs included lethargy, anorexia, and inability to dive. Many of the ill turtles floated on the surface of their tanks. There was no apparent sex predilection. Complete necropsies, including histopathologic examination of tissues, were performed on eight turtles. Necropsies revealed multiple irregular discrete to patchy 1–10-mm pale gray foci throughout the hearts of four turtles. By light microscopic examination, the most severe and consistent lesions were necrotizing myocarditis, histiocytic to fibrinous splenitis, and hepatic lipidosis and necrosis. A mixed leukocytic infiltrate of acidophils, macrophages, and lymphocytes was present in affected areas of the heart. Other lesions included lymphocytic/plasmacytic interstitial nephritis, subacute interstitial pneumonia, subacute mesenteric vasculitis, chronic/active enteritis of the small intestine, and occasional granulomas associated with spirorchid trematode ova. Chlamydiae could be demonstrated in macrophages in sections of paraffin-embedded heart, liver, and spleen and in myocardial fibers and hepatocytes using a modified Macchiavello's stain. Chlamydial antigen was detected by light microscopic examination in the cytoplasm of myocardial fibers and in occasional hepatocytes using a commercially available genus-specific antichlamydial monoclonal antibody and the avidin biotin peroxidase complex staining method. Electron microscopic examination of the heart of the most severely affected turtle revealed developmental stages of chlamydial organisms. A suspension of heart from this turtle was inoculated into the yolk sacs of chicken embryos. Chlamydial elementary bodies could be demonstrated in infected yolk-sac membranes approximately 7 days after inoculation.
Comparative Histopathology of Pemphigus Foliaceus and Superficial Folliculitis in the Dog
Authors: Kuhl K. A. , Shofer F. S. , Goldschmidt M. H.
Published: January 2010

A comparative histopathologic study of 50 cases of pemphigus foliaceus and 47 cases of superficial folliculitis in the dog was undertaken to identify those histopathologic features important in differentiating these diseases. All cases were diagnosed by the Surgical Pathology Service of the Laboratory of Pathology of the University of Pennsylvania, School of Veterinary Medicine, between January 1986 and March 1991. These cases were followed clinically to determine the accuracy of the initial histopathologic diagnosis. Data were analyzed by Fisher's exact test for discrete data and the Mann-Whitney U-test for continuous data. A probability of <0.05 was considered statistically significant. The following breeds were affected with pemphigus foliaceus: Akita, Brittany Spaniel, Chow Chow, Collie, Dachshund, Doberman Pinscher, English Cocker Spaniel, English Setter, Golden Retriever, Siberian Husky, Laborador Retriever, Miniature Schnauzer, Old English Sheepdog, Scottish Terrier, Chinese Shar Pei, Spitz, Shetland Sheep Dog, Weimeraner, and West Highland White Terrier. An increased risk of developing pemphigus foliaceus was noted in the Akita (OR = 37.8), English Springer Spaniel (OR = 20.7), Chow Chow (OR = 12.3), Chinese Shar Pei (OR = 7.9), and Collie (OR = 3.9). Pemphigus foliaceus had a higher average density of acantholytic cells (226 ± 22.9) than superficial folliculitis (11.8 ± 4.6), and acantholytic cells were 183 times more likely to be present in pemphigus foliaceus. The presence of rafts of acantholytic cells occurred in pemphigus foliaceus (23/50) more often than superficial folliculitis (1/47). Recornitication and reformation of pustules were, respectively, 13.4 and 3.6 times more likely to occur in pemphigus foliaceus. Finally, a longer pustule that bridges multiple hair follicles (2.3 ± 0.20 mm and 1.31 ± 0.10 mm, respectively) was seen in pemphigus foliaceus.
Juvenile-onset Neuronal Ceroid-Lipofuscinosis in Rambouillet Sheep
Authors: Edwards J. F. , Storts R. W. , Joyce J. R. , Shelton J. M. , Menzies C. S.
Published: January 2010

Two, 8-month-old Rambouillet half-sister ewes with signs of visual loss and decreased mentation were examined. Ewe No. 1 was necropsied at 10 months of age, and alter being held under observation for a further 6 months, ewe No. 2 was necropsied at 16 months of age. At that time, the ewe was blind and severely depressed. Both ewes had deposition of an autofluorescent lipopigment, identified as ceroid-lipofuscin, in neurons of the brain, spinal cord, eye, and dorsal root ganglia. The disease process was progressive and characterized by deposition of lipopigment with neuronal degeneration and severe fibrillary aslrogliosis. This progressive loss of neurons in the older ewe led to severe retinal degeneration. No pigment was observed in cells outside of the nervous system and eye. Controlled breeding studies have shown that this disease has an autosomal, recessive inheritance. The disease referred to here as juvenile-onset neuronal ceroid-lipofuscinosis of Rambouillet sheep is unlike the majority of the hereditary ceroid-lipofuscinoses that occur in human beings and animals in that only the nervous system is affected. Therefore, this disease could serve as an excellent model for the study of lipopigment deposition that affects the nervous system as a result of various disease states and during aging.
Tissue Factor Expression in Bovine Endothelial Cells Induced byPasteurella haemolyticaLipopolysaccharide and Interleukin-1
Authors: Breider M. A. , Yang Z.
Published: January 2010

Pasteurella haemolytica in cattle produces fibrinohemorrhagic pleuropneumonia characterized by extensive pulmonary microvascular thrombosis and parenchymal necrosis. The purpose of this in vitro study was to determine if P. haemolytica lipopolysaccharide (LPS) promotes vascular thrombosis by inducing a procoagulant state in vascular endothelial cells. After treatment of confluent monolayers of bovine pulmonary artery endothelial cells with various concentrations of either P. haemolytica LPS or Escherichia coli LPS, the procoagulant activity of the endothelial cells was determined using a chromogenic assay dependent on cellular tissue factor expression. The LPS treatment induced significant increases in cellular tissue factor expression in a LPS concentration- and time-dependent manner. Highest levels of tissue factor were present at 22 hours after treatment, although high LPS concentrations induced moderate tissue factor levels at 5 hours after treatment. Interleukin-1 also induced tissue factor expression in endothelial cells and enhanced the LPS-induced effects. This interleukin-1 effect could be diminished by concurrent use of an interleukin-1 receptor antagonist. These results demonstrate that LPS and cytokine promotion of a procoagulant state in endothelial cells occurs in vitro. Similar mechanisms may play a role in P. haemolytica-mediated pulmonary vascular thrombosis.
In Vitro and In Vivo Activity of Human Interleukin-8 in Dogs
Authors: Zwahlen R. D. , Spreng D. , Wyder-Walther M.
Published: January 2010

Interleukin-8 (IL-8), a proinflammatory cytokine produced by human monocytes, fibroblasts, and endothelial and epithelial cells, is effective not only on cells and tissues of human beings but also on those of several animal species. We investigated the importance of recombinant human IL-8 for the activation of canine neutrophils in vitro and its potential for inducing inflammation in vivo. Shape change (10-9–10-7M IL-8) and chemotaxis (10-10–10-6M IL-8) assays were used to determine the activation of canine neutrophils in vitro. Chemotaxis was induced by IL-8 at doses > 10-8M with a maximum response at 10-6M. A rapid shape change of comparable intensity was elicited by 10-9–10-7IL-8. Thirty minutes after intradermal injection of 10-9moles of IL-8, emigration of neutrophils could be observed and became more intense at 60 minutes and 240 minutes, respectively. Zymosan-activated canine plasma, which served as a positive control, induced a rapid, massive, and more diffuse neutrophil accumulation, whereas the reaction after IL-8 was weaker but still significant. The neutrophil accumulation after IL-8 was preferentially located in perivenular areas of the deep dermis. Recombinant human IL-8 is capable of activating canine neutrophils in vitro and is able to generate significant neutrophil accumulation in dog skin. Its activity is lower than that in human, rabbit, and rat systems.
Genital Lesions following Long-term Administration of Clenbuterol in Female Pigs
Authors: Biolatti B. , Castagnaro M. , Bollo E. , Appino S. , Re G.
Published: January 2010

Pathologic findings, lectin histochemistry, and nuclear estrogen receptors were studied in the reproductive organs of gilts treated with clenbuterol. A ration containing 1 ppm of clenbuterol was fed for 40 days to four Landrace x Large white, 9-month-old gilts, weighing 134 to 172 kg at slaughter (gilt Nos. 5–8). Four gilts (Nos. 1–4) served as controls. Treated animals had macroscopic lesions characterized by microcystic ovaries and uterine atrophy. Histopathologic lesions included atretic degeneration of many ovarian follicles, complete absence of functional corpora lutea, a reduction in the number of endometrial glands, and a decrease in cytoplasmic volume of endometrial and glandular epithelial cells. In ovaries, uterus, and vagina lectin histochemistry, performed with thirteen different biotinylated lectins, revealed a different staining distribution between control and treated gilts. The binding pattern of Ricinus communis agglutinin-1 (RCA-I) and -II (RCA-II) in the ovaries of control gilts, displayed labeling of cytoplasm in theca interna cells of Graafian follicles. There was no labeling of the same cells in treated gilts. Labeling patterns with Griffonia simplicifolia agglutinin-I (GS-I), Phaseolus vulgaris agglutinin (PHA), RCA-I and RCA-II documented a difference in the vascularis of the theca interna between Graafian follicles of control and treated gilts. The GS-1 and Ulex europaeus agglutinin-I (UEA-I) binding patterns in uterus and vagina of treated gilts when compared to control gilts suggested that there was a block of the cycling activity in the proliferative stage. Immunohistochemical staining for estrogen receptors in the endometrium was positive in all but one treated gilts, and negative to weakly positive in control gilts. Serum progesterone concentrations were decreased in treated animals when compared to control: estradiol concentrations were similar in both group of gilts. Cystic ovaries, uterine atrophy, and reduction in progesterone concentrations suggested that clenbuterol changed ovarian hormonal activity in treated animals.
Experimental Rabies Infection of Non-nervous Tissues in Skunks (Mephitis mephitis) and Foxes (Vulpes vulpes)
Authors: Balachandran A. , Charlton K.
Published: January 2010

Non-neural tissues, from three male and four female striped skunks ( Mephitis mephitis), 5 to 7 months old, and one male and two female red foxes ( Vulpes vulpes), 12 to 16 months old, experimentally infected with street rabies virus, were examined by light microscopic immunohistochemical and electron microscopic methods. This is the first report of ultrastructural lesions in rabies-infected adrenal medulla, cornea, and nasal glands. Using the streptavidin biotin peroxidase technique, antigen was detected in mucous cells and interstitial neurons and their processes in the submandibular salivary gland, in chromaffin cells of the adrenal medulla, in epidermal cells of the skin, in external root sheath cells of hair follicles, and in corneal epithelial cells. Electron microscopically, matrix (viral nucleocapsid), virions, and anomalous viral products were common in most tissues examined, but their relative proportions varied. The results suggested that replication with minimal accumulation of matrix and anomalous viral growth products was characteristic of growth in tissues (submandibular salivary gland) that frequently produce high titers of virus, whereas replication with large amounts of matrix and anomalous structures occurred in tissues (adrenal gland and nasal gland) that generally contained low or moderate titers of virus. Novel findings included viral budding into secretory granules, increase in microfilaments in infected mucogenic cells, and continuity of viral convoluted membranous profiles with rough endoplasmic reticulum of chromaffin cells and nasal glandular cells. The presence of viral antigen and developing virus in extra-neural tissues constitutes a potential risk of non-bite exposure to people in certain groups/occupations.
Immunohistochemical Staining of Feline Malignant Fibrous Histiocytomas
Authors: Pace L. W. , Kreeger J. M. , Miller M. A. , Turk J. R. , Fischer J. R.
Published: January 2010

Malignant fibrous histiocytoma was diagnosed in seven cats from biopsy specimens received at the University of Missouri Veterinary Medical Diagnostic Laboratory during a 4-year period from 1987–1991. Tissue blocks from formalin-fixed specimens were resectioned and stained for type I (AE1) and type II (AE3) cytokeratins, desmin, S100 protein, vimentin, and alpha1-antitrypsin by the avidin biotin peroxidase complex method with diaminobenzidine (DAB) chromogen. None of the tumors stained positively for alpha1-antitrypsin. Four of seven of the tumors had similar immunohistochemical staining results, with positive staining for type I and type II cytokeratins, desmin, S100 protein, and vimentin. Of the remaining three, one stained positively only for S100 protein and vimentin; one stained positively for vimentin only; and one was negative for all six antigens. Based only on immunohistochemical staining results, three of the tumors could possibly be reclassified: one as a melanoma, one as a probable fibrosarcoma, and one as unknown. These results also indicate that feline malignant fibrous histiocytomas show a diversity of intermediate filament expression, as do human tumors. Our results also do not support the theory that malignant fibrous histiocytomas are of histiocytic origin.
“Lipomatous” Lesions of Unknown Cellular Origin in the Liver of B6C3F1 Mice
Authors: Dixon Darlene , Yoshitomi Katsuhiko , Boorman Gary A. , Maronpot Robert R.
Published: January 2010

The gross, microscopic, and ultrastructural features of lipomatous lesions in the liver of B6C3F1 mice are described. The cases were selected from a database of 45,406 male and 45,674 female mice used as treated, control, or vehicle-control animals in the National Cancer Institute's Bioassays or the National Toxicology Program's 2-year carcinogenicity studies. Thirteen hepatic lesions identified from cases within the database were re-evaluated microscopically and selected for further study. These lesions were present in ten males and three females that were between 85 and 113 weeks of age at the time of death. Grossly, the liver lesions were described as white to yellow or red to brown nodules/masses or foci that ranged from 2.0 to 25 mm in diameter. The lesions commonly involved the median and left lateral hepatic lobes. Microscopically, many of the lesions closely resembled lipomas described in the liver of human beings, and they consisted of nonencapsulated mature adipose-like tissue with irregular margins. The majority of the cells that comprised the lipomatous lesions were signet-ring shaped. These cells were positive for lipid as evidenced with oil red-O. The lipid droplets were also present within the hepatocytes that comprised the hepatic plates trapped within or surrounding many of the lipomatous lesions. At the margins of many of the lesions there were spindle-shaped cells that contained small intracytoplasmic lipid vacuoles. These cells were often within a stromal matrix that had focal areas of collagen and mucopolysaccharides, as evidenced by weak staining with Masson's trichrome and periodic acid-Schiff's stains, respectively. There was also disruption of the reticulum fibers in many of the lesions, as noted with a Gomori's reticulum stain. Ultrastructurally, cytoplasmic organelles, such as rough endoplasmic reticulum, free ribosomes and small lipid vacuoles, were present in the spindle-shaped cells, whereas signet-ring-shaped cells had few discernible organelles due to peripheral compression of the cytoplasm by single large vacuoles occupying the cytoplasmic space. The spindle-shaped cells were free of lysosomes. Thin collagen fibers were seen in contact with some of the spindle-shaped cells and were located between these cells and adjacent hepatocytes, or endothelial cells lining sinusoidal capillaries. A distinct basal lamina was not associated with spindle- or signet-ring-shaped cells. Similar lipomatous lesions were not found in other visceral organs. The exact cellular origin of the hepatic lesions described here is not known.