Cytopathic effects and focus formation by reticuloendotheliosis viruses in a quail fibroblast cell line

The T and CS (chick syncytial) strains of reticuloendotheliosis virus (REV) induced focus formation and cytonecrotic changes in a Japanese quail fibroblast cell line designated QT35. The focus was distinctive and readily discernible, consisting of rounded refractile and larger dark-appearing (syncytia) cells usually aggregated along the periphery of a hole within a focus. The foci and cytopathic effects induced by the two strains of REV were morphologically indistinguishable. The focus formation in QT35 cultures was inhibited by chicken antiserum against the homologous or heterologous strain of REV; the homologous antiserum induced a greater inhibition. The altered cells composed of focus exhibited cytoplasmic fluorescence when stained by an indirect fluorescent-antibody technique with either the homologous or heterologous anti-REV serum. When foci that developed in QT35 cultures maintained under fluid medium were enumerated 3 days postinoculation, there were a highly significant correlation (P less than 0.001) and a linear relationship between the number of foci developed and relative virus concentration inoculated, thus justifying the validity of focus assay of REV by this system. The QT35 cell line may provide a useful in vitro system for virological and serological studies of REV.     

Congenital hepatic fibrosis in a newborn calf

Congenital hepatic fibrosis was observed in a newborn calf. Light microscopy revealed that periportal areas were linked via connective tissue to the central vein regions and to other periportal areas. Hyperplastic fibers were positive for type I collagen. A remarkable increase in the number of myofibroblasts that were positive for alpha-smooth muscle actin and vimentin was observed in the inner wall of the sinusoids, indicating the occurrence of various fibrogenesis. Ultrastractually, foci of cells resembling cholangiole epithelium cells were observed within the sinusoids, thereby suggesting either ductal plate dysplasia or a bile duct anomaly.     

An Unusual Necrotizing cholangiohepatitis in Broiler Chickens

A diagnosis of toxic necrotizing cholangiohepatitis was made in approximately 35% of a flock of 23,000 commercial broiler chickens. Affected chickens were small, and had discrete green foci throughout the liver. Seven to twelve days prior to shipping the flock to slaughter, premixes containing oxytetracycline, monensin, and 3-nitro-4-hydroxyphenylarsonic acid had been added to the ration because the birds had wet droppings and were growing slowly. The 3-nitro-4-hydroxyphenylarsonic acid had been inadvertently incorporated at ten times the recommended level. Liver and kidney of affected birds had elevated levels of total arsenic, and special strains demonstrated arsenic in necrotic foci in liver. Histologically there was marked dilation of intrahepatic bile ducts, and patchy necrosis and hyperplasia of the bile duct epithelium. Damage to bile ducts may have been a toxic manifestation of altered metabolism and excretion of the three drugs being fed to birds suffering from intercurrent diarrhea and/or undefined interactions among the drugs.     

Adenoviral hepatitis in a female bearded dragon (Amphibolurus barbatus)

A female bearded dragon (Amphibolurus barbatus) died following intermittent periods of inappetance. No significant gross lesions were found at autopsy, but histological examination revealed disordered liver architecture with numerous foci of coagulative necrosis. Eosinophilic intranuclear inclusions were present in many hepatocytes, some epithelial cells of the bile ductules and occasional epithelial cells of renal tubes and glomeruli. Large numbers of viral particles within many nuclei, associated with the intranuclear inclusion were demonstrated by electronmicroscopy. Similar particles, sometimes in paracrystalline arrays, were also seen within membrane-bound vesicles located next to the nuclei and to a lesser degree within the cytoplasm and extracellular spaces. The virus was considered to be an adenovirus on the basis of its size, morphology, site of formation and lack of envelopment. It was considered to he the cause of the hepatitis.     

Adenoviral hepatitis in a female bearded dragon (Amphibolurus barbafus)

A female bearded dragon (Atnphibolurus barbutus) died following intermittent periods of inappetance. No significant gross lesions were found at autopsy, but histological examination revealed disordered liver architecture with numerous foci of coagulative necrosis. Eosinophilic intranuclear inclusions were present in many hepatocytes, some epithelial cells of the bile ductules and occasional epithelial cells of renal tubes and glomeruli.

Large numbers of viral particles within many nuclei, associated with the intranuclear inclusion were demonstrated by electronmicroscopy. Similar particles, sometimes in paracrystalline arrays, were also seen within membrane-bound vesicles located next to the nuclei and to a lesser degree within the cytoplasm and extracellular spaces. The virus was considered to be an adenovirus on the basis of its size, morphology, site of formation and lack of envelopment. It was considered to he tlie cause of the hepatitis.     

Comparison of two quantitative assays for xenotropic murine leukemia virus-related virus

Xenotropic murine leukemia virus-related virus (XMRV), a novel gammaretrovirus in humans, was found in patients with prostate cancer (PC) and chronic fatigue syndrome (CFS). However, there has been controversy whether XMRV is directly associated with human diseases. In this study, we developed a LacZ marker rescue assay using human embryonic kidney 293T cells and a focus assay using a feline fibroblastic sarcoma-positive leukemia-negative QN10S cells. XMRV induced prominent foci in QN10S cells and the viral titer determined by the focus assay was as high as that by the LacZ marker rescue assay. Because the focus assay is simple and sensitive, it will be useful for monitoring infectious XMRVs in CFS and PC patients and virological studies for XMRV.     

Fibrosing cholehepatitis in broiler chickens induced by bile duct ligations or inoculation of Clostridium perfringens.

The pathogenesis of fibrosing hepatitis causing condemnations in broiler chickens was investigated. Three to four week old broilers were inoculated via the hepatoenteric bile duct with saline washed suspensions of Clostridium perfringens (10(7) and 10(8) organisms). In another group of broilers, both bile ducts were ligated. The sequential development of liver and gall bladder lesions was studied at intervals ranging from 1-28 days postsurgery. The lesions were similar in both experiments in that the liver became mottled and swollen by five to seven days. Fibrinoid necrosis, heterophil and lymphocyte infiltration, bile duct hyperplasia and fibrosis with reticulin fiber proliferation occurred. By 14-17 days, the liver was enlarged, tan colored and firm with red and white foci. By 28 days, bile duct proliferation and fibrosis were massive with only a few hepatocytes remaining. The liver capsule was not involved. Jaundice was not present but the birds with ligated bile ducts excreted intensely yellow stained droppings after six to seven days. The gall bladder in inoculated birds was edematous and distended with flocculent or inspissated material. Clostridium perfringens was reisolated from gall bladder and/or liver of inoculated birds up to 28 days postsurgery. It is suggested that this organism plays a role in the pathogenesis of fibrosing cholehepatitis by inducing septic intrahepatic cholestasis.     

Experimentally induced cholangiohepatopathy by dosing sheep with fractionated extracts from Brachiaria decumbens.

Cholangiohepatopathy was induced in 5 lambs by oral administration of extracts from signal grass (Brachiaria decumbens) in Brazil. Grossly there were pale foci multifocally distributed throughout the hepatic parenchyma in 4 lambs. The microscopic changes, which were similar to those produced by other steroidal sapogenins-containing plants such as Tribulus terrestris and Panicum spp., included multifocal cholangitis, bile duct proliferation, and the presence of crystals in the biliary system.     

Spinal oligodendroglioma with diffuse arachnoidal dissemination in a Japanese Black heifer

A gelatinous focus with cystic spaces, was found in the posterior funiculus of the 2nd to 3rd lumbar levels of the spinal cord of a Japanese Black heifer, 2 years old, with clinical signs of severe dysstasia. Histopathological examination revealed that the spinal lesion consisted of multifocal and diffuse proliferation of round cells with abundant vacuolar cytoplasm and hyperchromatic nuclei. In the lesions there was a number of cystic spaces containing aggregates of small round cells. The neoplastic foci showed a honeycomb structure divided by thin blood vessels, representing typical lesions of oligodendroglioma. Diffuse and multifocal proliferation of these round cells were also recognized in the subarachnoidal space in the sacral spinal cord. Immunohistochemically, the proliferating round cells were negative for glial fibrillary acidic protein. Based on these morphological features, the case was diagnosed as lumbar spinal oligodendroglioma with diffuse arachnoidal dissemination.     

Chronic liver disease: current concepts of disease mechanisms

Optimal management of chronic liver disease requires an understanding of aetiological factors or conditions initiating and sustaining tissue damage. Injury may derive initially from toxin or xenobiotic exposure (direct, biotransformation adducts, hypersensitivity responses or immune-mediated mechanisms), infectious organisms, inborn errors of metabolism, or pathological accumulations of transition metals (iron or copper), endotoxins or membranocytolytic bile acids. Secondarily, cells and mediators associated with inflammation, pathological expression of major histocompatibility foci on hepatocytes and biliary epithelia, aberrant initiation of apoptosis, modification of the extracellular matrix, and depletion of natural antioxidants can each play pivotal roles. Cholestatic liver injury derived from extrahepatic mechanical obstruction or intrahepatic cholestasis (many causes) can induce membrane damage subsequent to accumulation of membranocytolytic bile acids, copper retention, and membrane peroxidation. This paper reviews contemporary issues of chronic hepatocellular injury and hepatic fibrosis with the aim of broadening the clinical perspective of treatment strategies.     

Mesotheliomas and proliferative lesions of the testicular mesothelium produced in Fischer, Sprague-Dawley and Buffalo rats by methyl(acetoxymethyl)nitrosamine (DMN-OAc).

A single intraperitoneal dose of methyl(acetoxymethyl)nitrosamine (13 mg/kg body weight) given to 78 5-week-old male rats induced 25 mesotheliomas; two mesotheliomas were found in 67 control rats. All mesotheliomas arose from the peritesticular mesothelium and had a typical microscopic appearance of branching papillary fronds with a collagenous core covered by one or many layers of plump tumor cells. Cytoplasm of tumor cells contained material that reacted positively to a colloidal iron stain and was labile to hyaluronidase. In addition to frank mesotheliomas, 16 lesions, which we called atypical mesothelial proliferations, were found. These consisted of a single focus of plump mesothelial cells overlying an area of thick stroma. Often these foci included short, non-branched papillary projections above the surface of adjacent normal mesothelium. Twelve of the 16 lesions occurred in methyl(acetoxymethyl)nitrosamine-treated rats.     

S-adenosylmethionine and cAMP confer differential cytoprotection against bile acid-induced apoptosis in canine renal tubular cells and primary rat hepatocytes

Cholestasis results in the accumulation of cytotoxic bile acids in the body. The cytoprotective effect of S-adenosylmethionine (SAMe) and cAMP were compared in two in vitro models of bile acid-induced apoptosis. Primary cultures of rat hepatocytes and canine renal tubular cells (Madin-Darby canine kidney [MDCK] cells stably transfected with the conjugated bile salt transporter, sodium [Na+]/taurocholate cotransporting polypeptide [Ntcp]) were treated with conjugated bile acids and monitored for apoptosis. Glycine-conjugated bile acids caused similar amounts of apoptosis, whereas taurine-conjugated bile acids were five to 10 times more toxic in MDCK-Ntcp cells than in hepatocytes. Treatment with the 1,4-butanedisulfonate salt of SAMe (500 microM) or the stable chlorophenylthio-cAMP analogue (100 microM) inhibited bile acid-induced apoptosis in hepatocytes by 70% and 40%, respectively. In MDCK-Ntcp cells, SAMe inhibited apoptosis by 20%, but cAMP was without effect. Immunoblotting for activation of putative survival kinases in cAMP-treated cells (phosphorylated protein kinase B [Akt] or mitogen-activated protein kinase [MAPK]) was done using phosphospecific antibodies. cAMP increased Akt phosphorylation threefold in hepatocytes but not in MDCK-Ntcp cells. Activation of p42/p44 MAPK was inhibited by cAMP in both cells. SAMe protects against bile acid-induced apoptosis in hepatocytes and MDCK-Ntcp cells. The cytoprotective effect of cAMP is seen only in hepatocytes and may reflect tissue-specific activation of Akt.     

Expression of the sweet receptor protein, T1R3, in the human liver and pancreas

The expression of T1R3, a taste receptor essential for the perception of sweetness and umami-taste, was examined by immunohistochemistry to determine whether and where it may be localized in the liver and pancreas. In the liver, both immunopositive and immunonegative reactions were detected; bile ducts and intercalated portions of the bile ductules were immunopositive to T1R3, while arterioles and venules were immunonegative in interlobular connective tissue. In the hepatic lobule, all other cells including liver cells (hepatocytes) and bile capillaries were immunonegative. In the pancreas, all endocrine portions of the pancreas were immunonegative to T1R3. Within the exocrine portions, immunopositive reactions were detected in excretory duct cells, intercalated cells, and centroacinar cells. In contrast, acinar cells were immunonegative, as were vessels, lymph capillaries, nerve fibers, and connective tissue cells in the exocrine portions. The restricted localization of T1R3 in the duct cells of the liver and pancreas in the present study may indicate that T1R3 is involved in monitoring changes in the makeup of bile and pancreatic juices in the hepatic and pancreatic duct systems.     

Nonsuppurative myocarditis associated with so-called fowl glioma

C/O specific pathogen-free White Leghorn chickens were intracerebrally inoculated at one day of age with a brain homogenate of Japanese bantams (Gallus gallus domesticus) affected with fowl glioma. Histologically, six of eight inoculated chickens developed nonsuppurative meningoencephalitis in cerebrum and two of them had the characteristic lesions of fowl glioma. Hyperplastic lymphoid foci concomitantly developed in many organs of these birds, especially in the heart. Apart from these lymphoid foci, lymphocytic myocarditis was observed in all inoculated birds. Matrix inclusions were also noted in myocardial cells. Immunohistochemically, avian leukosis virus antigens were detected in reticular cells in the lymphoid foci, mesangial cells of the kidney, smooth muscle cells of the blood vessels, and myocardial cells. Of these tissues, the myocardium of all inoculated birds consistently showed strong reactivity for this antigens. The matrix inclusions were also positive for the antigens. These results suggest that the causal virus of fowl glioma has a high propensity to replicate, especially in myocardium and nonsuppurative myocarditis occurs associated with so-called fowl glioma.     

Ultrasonographic findings in cattle and buffaloes with chronic hepatic fascioliosis

The purpose of this study was to characterize the ultrasonographic findings in cattle and buffaloes with chronic hepatic fascioliosis. To the best of the author's knowledge, this report is the first to document ultrasonographic findings in buffaloes with chronic hepatic fascioliosis. Ultrasonographic findings included distended gallbladders with either homogenous or heterogeneous contents, edema of the gallbladder walls, which ranged from mild or moderate to severe and bile duct mineralization. In 78% of the buffaloes, there was an ultrasonographic picture of hepatic fibrosis in which heterogeneous and hyperechogenic hepatic parenchymas with multiple echogenic foci were imaged. Other ultrasonographic findings included peritoneal, pleural and pericardial effusions. Two cows and one buffalo were slaughtered and examined postmortem. Hence, it was possible to verify distended gallbladders, edema of the gallbladder wall, calcified bile ducts, cholestasis and hepatic fibrosis by using ultrasonography in the cows and buffaloes with chronic hepatic fascioliosis. The procedure offers a useful supplement to clinical, hematological and biochemical examinations on the diagnosis of this condition.     

Cell proliferation activity of proliferating bile duct after bile duct ligation in rats

The cell proliferation activity of proliferating bile ducts produced by bile duct ligation (BDL) in rats was examined histologically, immunohistochemically, and ultrastructurally. Proliferating bile ducts, which were similar to normal bile ducts, increased with time after BDL. The cell proliferation activity of proliferating bile ducts, measured using proliferating-cell nuclear antigen and 5-bromo-2'-deoxyuridine antibodies, tended to be high at 1 and 3 days after BDL and decreased progressively at 2 to 4 weeks after BDL. On the other hand, alpha-smooth muscle actin-positive myofibroblast-like cells increased continuously after BDL. These findings indicate that there is a negative correlation between the cell proliferation activity of proliferating bile ducts and that of myofibroblast-like cells.     

Malignant peripheral nerve sheath tumor as a cause of chronic cardiac insufficiency in cattle

Chronic cardiac insufficiency was associated with a malignant peripheral nerve sheath tumor in a cow. An eight-year-old cow developed a progressive condition (over a period of three months) characterized by an enhanced abdominal volume, reluctance to move, a positive jugular pulse, watery diarrhea and death. At necropsy, moderate subcutaneous edema and an enhanced hepatic lobular pattern were observed. A 23x20x11 cm firm, grayish-white mass adhered to and infiltrated the right atrium. Multiple firm, yellowish-white nodules of 0.5 to 12 cm in diameter were diffusely scattered in the epicardium and parietal pericardium. Histologically, the tumor was poorly circumscribed with foci of infiltration of the myocardium. The neoplastic cells had two major histologic patterns, Antoni types A and B. Within occasional foci, pleomorphic cells with an epithelioid appearance were present in addition to multinucleated cells with periodic acid Schiff (PAS)-positive cytoplasmic globules. Foci of cartilaginous and granular differentiations were interspersed among the neoplastic cells. Multiple vessels presented wall hyalinization and tumoral embolus. Large necrotic foci with mineralization and cholesterol clefts were also observed. Immunohistochemically, the tumor was positive for S100 protein, vimentin and neuron-specific enolase labeling.     

Multiple hepatic peribiliary cysts in a young pig

Histopathologic features of hepatic peribiliary cysts were described in a young slaughtered pig. The animal was an apparently healthy 6-month-old pig of mixed breed. Macroscopically, all lobes of the liver contained numerous cysts of varying size containing serous fluid in all lobes. Histopathologically, the cysts were located mainly around the large bile duct and in the connective tissue of the portal tracts. Within serial sections, these cysts were assumed to be solitary or multilocular, but they were separated from the bile duct. The cysts were lined by a single layer of columnar, cuboidal, and flattened epithelial cells. Occasionally, goblet cells were observed. The epithelial cells were stained with periodic acid-Schiff/alcian blue and high-iron diamine/alcian blue, indicating the presence of neutral mucin, sialomucin, and sulfomucin. Grimalius' method revealed the presence of endocrine cells in the lining epithelium. There was no bile pigment in the cysts by the Hall method.     

Cutaneous Hemangiosarcoma in a Dog

A male golden retriever of unknown age presented with multiple cutaneous and subcutaneous masses from the left elbow to the digits. Histopathologically, multiple tumor foci had formed from the dermis to the subcutaneous tissue. Tumor foci consisted of a vascular structure, alveolar structure and solid proliferative area. The borders among these areas were not clear. Some neoplastic cells resembled a mature endothelium, while others were large pleomorphic cells. Immunohistochemically, the tumor cells were usually strongly positive for CD31 and often positive for PROX-1, the lymphatic endothelial cell marker. Based on these findings, the tumor was diagnosed as a hemangiosarcoma with lymphatic differentiation.