Rift Valley fever virus infection in golden Syrian hamsters

Rift Valley fever virus (RVFV) is a formidable pathogen that causes severe disease and abortion in a variety of livestock species and a range of disease in humans that includes hemorrhagic fever, fulminant hepatitis, encephalitis and blindness. The natural transmission cycle involves mosquito vectors, but exposure can also occur through contact with infected fluids and tissues. The lack of approved antiviral therapies and vaccines for human use underlies the importance of small animal models for proof-of-concept efficacy studies. Several mouse and rat models of RVFV infection have been well characterized and provide useful systems for the study of certain aspects of pathogenesis, as well as antiviral drug and vaccine development. However, certain host-directed therapeutics may not act on mouse or rat pathways. Here, we describe the natural history of disease in golden Syrian hamsters challenged subcutaneously with the pathogenic ZH501 strain of RVFV. Peracute disease resulted in rapid lethality within 2 to 3 days of RVFV challenge. High titer viremia and substantial viral loads were observed in most tissues examined; however, histopathology and immunostaining for RVFV antigen were largely restricted to the liver. Acute hepatocellular necrosis associated with a strong presence of viral antigen in the hepatocytes indicates that fulminant hepatitis is the likely cause of mortality. Further studies to assess the susceptibility and disease progression following respiratory route exposure are warranted. The use of the hamsters to model RVFV infection is suitable for early stage antiviral drug and vaccine development studies.

Effect of oxymatrine on murine fulminant hepatitis and hepatocyte apoptosis

OBJECTIVE

To evaluate the protective effects and mechanism of action of oxymatrine (OM) on the experimental fulminant hepatitis (FH) and early hepatocyte apoptosis in murine liver tissue.

METHODS

Fulminant hepatitis mice were induced by injecting lipopolysaccharide (LPS) intraperitoneally (ip) in galactosamine (GalN) sensitized mice. Two separate experiments were designed, including saline control group, fulminant hepatitis group and oxymatrine pretreated group (50 mg/kg, intraperitoneally, bid x 3 days). The levels of serum tumor necrosis factor alpha (TNFa) in mice from two experiments were determined at 5-hour and 7.5-hour after injecting galactosamine/lipopolysaccharide. Mouse liver samples at 5-hour time point were obtained for in situ end labeling (ISEL) staining and ultrastructural observation of apoptotic cells under transmission electron microscope (TEM). Liver samples at 7.5-hour time point were taken for hematoxylin-eosin (HE) staining and immunohistochemical staining of Fas and its ligand (FasL).

RESULTS

As compared with the fulminant hepatitis group, the levels of serum tumor necrosis factor alpha in mice from the OM pretreated group at 5-hour and 7.5-hour time point were all significantly decreased (P < 0.05 and P < 0.01 respectively). Hepatocyte apoptosis in mice at 5-hour time point was significantly inhibited (P < 0.01). Both the degree of liver injury and the degree of Fas and Fas ligand expression in the OM pretreated group were reduced remarkably (P < 0.01 and 0.05 respectively) when compared with the saline control group.

CONCLUSIONS

Oxymatrine protects mice from fulminant hepatitis induced by GalN/LPS and may block hepatocyte apoptosis and subsequent necrosis through downregulating the production of serum tumor necrosis factor alpha and the expression of Fas and Fas ligand in liver tissue.

Genetic regulation of autoimmune disease: BALB/c background TGF-beta 1-deficient mice develop necroinflammatory IFN-gamma-dependent hepatitis

Autoimmune hepatitis (AIH) in humans arises spontaneously in genetically susceptible individuals and is associated with the presence of Th1 cells in the liver. The understanding of AIH has advanced more slowly than that of other organ-specific autoimmune diseases, however, largely because of the lack of an appropriate animal model. We now describe a new mouse model characterized by spontaneous development of necroinflammatory hepatitis that is restricted by genetic background. Mice deficient in the immunomodulatory cytokine TGF-beta1 were extensively back-bred to the BALB/c background. The BALB/c background dramatically modified the phenotype of TGF-beta1(-/-) mice: specifically, BALB/c-TGF-beta1(-/-) mice developed a lethal necroinflammatory hepatitis that was not observed in TGF-beta1(-/-) mice on a different genetic background. BALB/c background TGF-beta1(-/-) livers contained large numbers of activated CD4(+) T cells that produced large quantities of IFN-gamma, but little IL-4, identifying them as Th1 cells. BALB/c background TGF-beta1(-/-)/IFN-gamma(-/-) double knockout mice, generated by cross-breeding, did not develop necroinflammatory hepatitis, demonstrating that IFN-gamma is mechanistically required for its pathogenesis. This represents the first murine model of hepatitis that develops spontaneously, is restricted by genetic background, and is dependent upon the Th1 cytokine IFN-gamma, and that thus recapitulates these important aspects of AIH.

Inhibition of Fas-mediated fulminant hepatitis in CrmA gene-transfected mice

Hyperimmune response via Fas/Fas-ligand and perforin/granzyme pathways may be essential in pathogenesis of virus-induced fulminant hepatitis. CrmA inhibits activation of caspases and granzyme B, suggesting it may block these pathways. We investigated whether CrmA expression would inhibit Fas-associated lethal hepatitis in mice. We successfully generated AxCALNLCrmA, a recombinant adenovirus expressing CrmA gene with a Cre-mediated switching cassette. We increased CrmA expression level in the liver transfected with AxCALNLCrmA (10(9) pfu) by increasing administration dose (10(7)-10(9) pfu) of AxCANCre, a recombinant, adenovirus-expressing Cre gene. Injection of anti-Fas antibody into the control mice rapidly led to animal death due to massive liver apoptosis, while the apoptosis was dramatically reduced in the CrmA-expressed mice. The animal survival increased with an increase of CrmA expression. The formation of active caspase-3 was markedly inhibited in the crmA-transfected hepatocytes in vitro. These results suggest that crmA is an effective gene that can inhibit immune-related liver apoptosis.

Hepatoprotective effects of Inula britannica on hepatic injury in mice

Inula britannica, a Kampo medicine, is prepared from the heads of Compositae plants such as Inula britannica L., which has been used clinically as a remedy for nausea, hiccup and excessive sputum. Here it is shown that administration of Inula britannica improves the survival rate of mice with hepatic injury induced by LPS/PA. It is also suggested that administration of Inula britannica significantly reduces the fluctuation in the amount of cytokine in the spleen of mice with hepatic injuries, and that the Th1/Th2 control effect is related to the inhibitory action of Inula britannica against hepatic injury. In vitro testing suggests that Inula britannica suppresses Th1 differentiation and induces Th2 differentiation by inhibiting the production of macrophage IL-12 and promoting the production of IL-10, thus showing the immunological effect of hepatic injury inhibition by affecting the balance between Th1 and Th2.

Activation of caspases in lethal experimental hepatitis and prevention by acute phase proteins

Lethal hepatitis can be induced by an agonistic anti-Fas Ab in normal mice or by TNF in mice sensitized to d -(+)-galactosamine or actinomycin D. In all three models, we found that apoptosis of hepatocytes is an early and necessary step to cause lethality. In the three models, we observed activation of the major executioner caspases-3 and -7. Two acute-phase proteins, alpha1-acid glycoprotein and alpha1-antitrypsin, differentially prevent lethality: alpha1-acid glycoprotein protects in both TNF models and not in the anti-Fas model, while alpha1-antitrypsin confers protection in the TNF/d -(+)-galactosamine model only. The protection is inversely correlated with activation of caspase-3 and caspase-7. The data suggest that activation of caspase-3 and -7 is essential in the in vivo induction of apoptosis leading to lethal hepatitis and that acute phase proteins are powerful inhibitors of apoptosis and caspase activation. Furthermore, Bcl-2 transgenic mice, expressing Bcl-2 specifically in hepatocytes, are protected against a lethal challenge with anti-Fas or with TNF/d -(+)-galactosamine, but not against TNF/actinomycin D. The acute-phase proteins might constitute an inducible anti-apoptotic protective system, which in pathology or disturbed homeostasis prevents excessive apoptosis.

Clinical features of inflammatory liver disease in cats: 41 cases (1983-1993)

OBJECTIVE

To compare the clinical and clinicopathologic findings in and prognosis for cats with lymphocytic portal hepatitis (LPH) versus cats with acute or chronic cholangiohepatitis (CH).

DESIGN

Retrospective study.

ANIMALS

25 cats with LPH; 16 cats with CH (7 acute, 9 chronic).

PROCEDURE

Cats with LPH and CH were selected by evaluating records from liver biopsy specimens submitted to the University of Minnesota Veterinary Teaching Hospital during a 10-year period. Clinical and clinicopathologic data were retrieved.

RESULTS

Cats with CH had higher segmented and band neutrophil counts, alanine aminotransferase activities, and total bilirubin concentrations than did cats with LPH. Cats with acute CH had higher segmented and band neutrophil counts and lower serum alkaline phosphatase activities and total bilirubin concentrations than did cats with chronic CH. Twelve of 14 cats with LPH or CH had coarse or nodular texture to the liver on ultrasonography, with loss of portal vein wall clarity noticed in 4 of 8 cats with LPH. Sixteen of 23 cats with LPH and 8 of 15 cats with CH survived > 1 year. Of those cats living < 1 year, all cats with LPH and 5 of 7 cats with CH had a serious concurrent illness that may have been responsible for their deaths.

CLINICAL IMPLICATIONS

LPH and CH can be detected and tentatively differentiated through evaluation of clinical laboratory test results, but histologic evaluation of liver specimens is necessary for definitive differentiation. Survival time was good regardless of the type of inflammatory liver disease.

High-level constitutive expression of alpha 1-acid glycoprotein and lack of protection against tumor necrosis factor-induced lethal shock in transgenic mice

alpha 1-Acid glycoprotein (AGP) is an acute phase protein produced by hepatocytes. Although its exact biological function remains controversial, it was shown to protect galactosamine-sensitized or normal mice against hepatitis and lethal shock induced by tumor necrosis factor (TNF). Rat-AGP-transgenic mice, constitutively producing several mg AGP per ml serum were tested for their response to a combined challenge with TNF and D-(+)-galactosamine. A previously characterized, single transgenic line (9.5-5) was used. In contrast to our expectations both heterozygous or homozygous transgenic mice were not protected by the endogenously overproduced AGP. However, both transgenic and non-transgenic mice were protected by pretreatment with interleukin-1, an effect which we believe is mediated by the induction of acute phase proteins like AGP. Furthermore, both types of mice were protected by exogenous bovine AGP, suggesting that the lack of protection by endogenous AGP is not because of a repressed response to AGP. Finally, we demonstrate that purified AGP from the serum of transgenic mice is as protective as the AGP from non-transgenic mice or rats. The results suggest that AGP is protective only when its concentration is rapidly induced, perhaps because the endogenous steady state synthesis of AGP, in non-transgenic as well as transgenic mice, is coupled to the production of an AGP-binding factor. This study provides an interesting example of differences in outcome to a lethal challenge between an acute administered and a chronically produced protective protein.

An outbreak of infectious hepatitis in commercially reared ostriches associated with Campylobacter coli and Campylobacter jejuni

A disease causing high morbidity and mortality was observed in young ostriches from six properties in southeast Queensland, Australia. The disease affected birds from 2-8 weeks of age and was characterised clinically by bright-green urates and pathologically by severe necrotic hepatitis. The liver lesions resembled those of vibrionic hepatitis in other avian species. Campylobacter coli was isolated from the livers of affected ostriches from five of the six properties. Campylobacter jejuni subsp. jejuni was isolated from birds from the remaining property. Pulsed-field gel electrophoresis-based (PFGE) typing of representative isolates indicated that trade of infected birds between farms was an important factor in the spread of C. coli. Phenotypic and genotypic data suggest a clonal variant of the principal outbreak type may account for the remaining cases from which C. coli was found. Conventional biochemical test results and PFGE clearly distinguished the C. jejuni strain isolated from the geographically remote farm from the outbreak of C. coli type. We believe this to be the first definitive report of avian hepatitis associated with C. coli.

Diagnosis and prognosis of chronic hepatitis and cirrhosis in dogs

The purpose of this investigation was to evaluate the significance of enzymatic and biochemical analyses in the classification of chronic inflammatory liver disease and to evaluate the prognosis of these diseases. Chronic hepatitis and cirrhosis were diagnosed by histopathological examination in 79 dogs. Decreased appetite and lethargy were the most common owner complaints (46/79). Vomiting and, or, diarrhoea were reported in 27/79 dogs. Ascites was the most common clinical sign (43/79), whereas icterus was a more unusual finding demonstrated in 16/79 dogs. Liver cirrhosis was diagnosed most frequently, in 33/79 dogs, followed by chronic progressive hepatitis (22/79), chronic cholangiohepatitis (13/79), and chronic non-specific hepatitis (11/79). Hypoalbuminaemia was the most consistent biochemical aberration in liver cirrhosis (25/26) and in chronic progressive hepatitis (13/18). These diseases also showed normal to mildly increased concentrations of serum alanine aminotransferase (ALT) and serum gamma-glutamyl transferase (GGT) and a moderate to marked increase of serum alkaline phosphatase (ALP) and fasting serum bile acid (SBA) concentrations. As expected, icterus and markedly elevated ALT, ALP, GGT and SBA levels were demonstrated in chronic cholangiohepatitis. In this disease hypoalbuminaemia was shown in 6/12 dogs, whereas in dogs with chronic non-specific hepatitis, mean SBA and albumin concentrations were normal. In liver cirrhosis the prognosis was poor, with 94 per cent of the dogs dead within one week of established diagnosis. For dogs with the other types of chronic hepatitis the prognosis was more favourable with the mean survival time ranging from 21.1 to 36.4 months.

Occurrence of autoimmune antibodies to liver microsomal proteins associated with lethal hepatitis in LEC rats: effects of TJN-101 ((+)-(6S,7S,R-biar)- 5,6,7,8-tetrahydro-1,2,3,12-tetramethoxy-6,7-dimethyl-10,11- methylenedioxy-6-dibenzo[a,c]cyclooctenol) on the development of hepatitis and the autoantibodies

Long Evans Cinnamon (LEC) rats, that spontaneously develop hepatitis, were found to possess autoantibodies to liver microsomal proteins (anti-LM) before the development of hepatitis. Anti-LM antibody was assumed to appear in association with the lethal hepatitis in the LEC rats. Thus, the purpose of this study was to investigate the effects of an anti-hepatitis drug on the development of hepatitis and the occurrence of the antibody in LEC rats. Mortality, blood biochemical parameters and the titer of serum anti-LM antibody were measured. In control LEC rats, 4 of 8 rats died before 20 weeks of age. In rats treated with TJN-101 ((+)-(6S,7S,R-biar)-5,6,7,8-tetrahydro-1,2,3,12-tetramethoxy -6,7-dimethyl-10,11 - methylenedioxy-6-dibenzo[a,c]cyclooctenol), 4 of 7 rats died of hepatitis, but the time of death was delayed by 7-10 weeks compared to the control rats. The titer of the anti-LM antibody increased 3-7 weeks before death in the non-survivors in control and TJN-101-treated rats, supporting the idea that anti-LM antibody occurs in association with acute lethal hepatitis.

Effects of cyclosporin-A and D-penicillamine on the development of hepatitis and the production of antibody to protein disulfide isomerase in LEC rats

Long Evans Cinnamon (LEC) rats, which spontaneously develop hepatitis, produce an autoantibody to protein disulfide isomerase (PDI) before the development of clinical signs of hepatitis. Anti-PDI antibody may be associated with immunological hepatitis. Thus, the purpose of this study was to investigate the effects of some drugs on the development of hepatitis and the occurrence of the antibody in LEC rats. Cyclosporin-A, an immunosuppressant, and D-penicillamine, which promotes copper excretion, were orally administered to LEC rats for 23 weeks. Mortality, blood biochemical parameters and the titer of serum anti-PDI antibody were measured. In control LEC rats, four of eight rats died before 20-weeks-old. Only one of seven rats in the cyclosporin-A-treated group died at the age of 20 weeks. When rats were treated with D-penicillamine, the development of clinical signs of hepatitis was inhibited, and all rats survived. Cyclosporin-A-treated rats showed increases in blood biochemical parameters similar to those in control rats. The titer of anti-PDI antibody in control rats was higher the non-survivors than survivors. These findings suggest the association of the anti-PDI antibody with lethality, but not with the apparent development and progression of hepatitis as measured by blood biochemical parameters in LEC rats.

Disease-husbandry associations in farmed crocodiles in Queensland and the Northern Territory

To investigate husbandry-disease associations in farmed crocodiles 7 farms in Queensland and the Northern Territory were visited and details of past and present farm design and husbandry practices were recorded. In addition pathological examination of 300 (mostly young) crocodiles was carried out (85 necropsied, one biopsied and 214 examined retrospectively). Mortality rate and occurrence of disease, especially opportunistic infections with bacteria and fungi, were highest during winter months and in farms located at greater latitudes. A difference in the presence and prevalence of disease between the initial establishment phase of Northern Territory crocodile farms (1984-87) and currently (1988-91) was apparent; parasitic infections are now relatively infrequent and bacterial septicaemias and mycoses less common as a result of some provision of artificial heating for juveniles. Gross and microscopic changes observed in visceral and periarticular gout, bacterial hepatitis/septicaemia, deep and superficial mycosis, pentastomiasis and other parasitic infections are described.

Survey of Saguinus mortality in a zoo colony

Six years of necropsy records from a zoo colony of four tamarin species (Saguinus oedipus, S. geoffroyi, S. imperator, and S. mystax) were examined. Mean age at death was 4.0 years, average length in the colony at time of death was 3.4 years. Annual mortality rate varied between 9 and 30%. Gross necropsy findings, histopathologic, and bacteriological results indicate primary cause of death as follows: peritonitis (26%), septicemia (14%), nephritis (5%), hepatitis (5%), pneumonia (2%), and others.

Effects of corticosteroid treatment on survival time in dogs with chronic hepatitis: 151 cases (1977-1985)

Medical records of 151 dogs with chronic hepatitis were reviewed. Corticosteroid treatment had a statistically significant (P less than 0.005) effect on improving survival time when corticosteroid-treated dogs were compared with untreated dogs. Dogs dying within 1 week of examination represented 37.1% of the cases, and when compared with those living more than 1 week, serum glucose concentration was significantly lower (P less than 0.001); prothrombin time and partial thromboplastin time were significantly longer (P less than 0.001); blood ammonia concentration after oral administration of ammonium chloride was significantly higher (P less than 0.05); and necrosis severity and fibrosis severity were significantly greater (P less than 0.05 and P less than 0.022, respectively). The best predictors of early death were low normal serum glucose concentration (P less than 0.001) and prolonged prothrombin time (P less than 0.030), which was abnormal in 60.0% of dogs dying early. Partial thromboplastin time, which was increased in 92.0% of dogs dying early and in 42.6% of dogs living more than 1 week, was a less reliable predictor. Plasma ammonia concentration after oral administration of NH4Cl was least reliable in predicting early death. In dogs living more than 1 week, hypoalbuminemia was a predictor of shorter survival time (P less than 0.003). Of all the histologic features evaluated, only necrosis severity and fibrosis severity were accurate predictors of early death. The presence of bridging fibrosis was a predictor of shorter survival time in dogs living more than 1 week (P less than 0.0002).

Suspected hepatotoxicity in neonatal foals: preliminary report of an emerging syndrome

An apparently new and emerging fatal hepatic disease affecting foals is described. Characteristics included evidence of hepatic failure, marked biliary hyperplasia, hepatocellular necrosis and occasionally fibrosis. Generally, the features of the disease appear to differ markedly from other hepatic diseases of neonatal foals.

Effect of various doses of cerium on the serum level of ornithine-carbamyltransferase in rats

The relationships between different cerium doses administered intravenously as CeCl3 and the mortality of rats and their serum OCT level were studied. The LD50/30 value for cerium given intravenously to rats was 5.56 mg Ce/kg. A directly proportional correlation was demonstrated between intravenously administered Ce doses and the serum OCT level above a threshold dose.

Genetic study of mouse sensitivity to MHV3 infection: influence of the H-2 complex

Genetic study of acute and chronic mouse hepatitis virus type 3 disease was carried out in segregating generations of a cross involving a susceptible (C57BL/6) and a resistant (A/J) mouse strain. The data obtained indicate that one or two recessive genes may be involved in resistance of acute and chronic diseases but suggest that the genes involved in both diseases are different. In this cross, no correlation was observed between H-2 and acute or chronic disease. In mice of congenic lines, however, A/Sn (H-2a), A.SW (H-2s), A.BY (H-2b), and A.CA (H-2f), it appeared that the presence of the H-2f allele conferred to heterozygote as well as to homozygote animals the capacity to resist the development of chronic disease. It seems, therefore, that MHV3 sensitivity in mice is under the influence of at least two major genes: one for the acute disease and the other, H-2 linked, for the chronic disease.

Response of nude mice to a mouse hepatitis virus isolated from a wasting nude mouse

Chronic active hepatitis was produced in nude mice after inoculation with a mouse hepatitis virus from a natural nude case which was incapable of causing fatal infection in haired heterozygous mice without cortisone. Survival time of infected nude mice varied greatly from 1 to 10 weeks after the inoculation. Degeneration and necrosis of hepatocytes, apparition of small and megalocytic hepatocytes, and infiltration of lymphocytes and plasma cells with fibrosis, were most remarkable in those which died 3 weeks or more after inoculation. No such severe hepatic lesions were recognized in heterozygous haired litter-mates after inoculation of the same virus. Necrotic lesions with poor inflammatory reactions were seen in the brain of all infected and dead nude mice, while some cerebral lesions with apparent perivascular infiltration were detected in heterozygous ones only at early stage of infection.

Pathogenicity of mouse hepatitis virus for mice depending upon host age and route of infection

Day-old to 4-week-old mice from a breeder colony which had been seromonitored to be free from mouse hepatitis virus infection, were tested for susceptibility to the virus by different routes of inoculation. After intraperitoneal, intravenous and intracerebral inoculation of 10(2) or more plaque-forming units of the virus, mice of all ages died of acute hepatitis. While day-old mice died also after subcutaneous, intranasal and peroral routes of inoculation, those 3 weeks or more of age resisted to infection by these routes. To intranasal inoculation mice 1 and 2 weeks of age were fully susceptible but some of the resisted to peroral inoculation. In the course of non-fatal infection in 4-week-old mice after intranasal inoculation, viremia and production of some hepatic lesions were recognized and infection became fatal in association with cortisone treatment. The results suggested that the intranasal route of infection may be of importance for spreading of infection in mouse breeding colonies in which inapparent infection is prevailing.

Husbandry of the "nude" mouse in conventional and germfree environments

The "nude" mouse is a unique tool for immunologic studies. Its relatively short life span dictates the application of rigid environmental controls to increase longevity if the mouse is to assume the role of a practical experimental animal. In this paper we discussed the husbandry procedures employed to raise "nude" mice in our facilities under conventional, defined flora, and germfree conditions. Conventional and defined flora mice were raised on laminar flow stay-clean rocks, and germfree "nudes" were housed in self-contained germfree isolators. The major cause of morbidity and mortality among conventional and defined flora "nude" mice was fulminating hepatitis. We presented evidence that the etiologic agent of the disease was mouse hepatitis virus (MHV). Germfree "nude" mice were completely free from viral and bacterial diseases.

Effect of phenobarbital on MHV-3 viral hepatitis of the mouse

The effects of oral phenobarbital (PB) administration on MHV-3 viral hepatitis in the mouse were studied. PB was effective in increasing liver cytochrome P-450 level in infected animals at 72 h after virus inoculation, but did not affect the disease process of the liver viral infection as judged by changes in mortality rate, serum GOT, GPT and MDH levels and liver virus content.

Polychlorinated biphenyl: interaction with duck hepatitis virus

Ten-day-old mallard ducklings fed a polychlorinated biphenyl at concentrations of 25, 50, and 100 parts per million for 10 days suffered no apparent clinical intoxication. Five days later these birds were challenged with duck hepatitis virus, and they suffered significantly higher mortality than birds which were not exposed to the polychlorinated biphenyl.