Objective-We have established a hereditary postprandial hypertriglyceridemic (PHT) rabbit. The present study was designed to define whether this rabbit model represents both insulin resistance and central obesity. Methods and Results-Body weight, abdominal circumference, visceral fat weight, and glucose tolerance were compared between PHT and Japanese white (JW) rabbit. Plasma levels of triglycerides (TG), total cholesterol (TC), glucose, and insulin were measured before and after feeding. Abdominal circumference of PHT rabbit was larger than that of JW rabbit, with no difference in body mass index. Visceral fat accumulation was noted as obvious in mesenterium, retroperitoneal space, and epididymal area. Plasma TG and TC levels were high preprandially and markedly increased postprandially in PHT rabbit compared with JW rabbit. Although plasma glucose levels were comparable in both groups, plasma insulin levels were elevated in PHT rabbit. Glucose tolerance tests indicated that plasma insulin levels in PHT rabbit were consistently higher than in JW rabbit. A positive correlation was observed between plasma insulin levels and visceral fat weight in PHT rabbit. underlying milieu of atherosclerosis. 1-3 Recent US statistics show that metabolic syndrome affects Ϸ1 in 4 adults and that the incidence of metabolic syndrome is sharply increasing with the growing population of obese individuals with visceral adiposity due partly to overeating, lack of physical exercise, and a high-fat diet. 4 In light of its clinical significance, development of therapeutic remedies for metabolic syndrome is of prime importance and therefore the establishment of an animal model is urgently required. Conclusions-PHTMetabolic syndrome is characterized by a clustering of several cardiovascular risk factors in a single individual, including dyslipidemia, centrally distributed adiposity, hypertension, and syndromes of glucose intolerance. Although multiple disorders were partly modeled by glucose intolerance in heritable rodent models, 5,6 lipid metabolism differs considerably between humans and rodents (eg, lack of cholesteryl ester transfer protein, differences in the apoB synthesis pathway). 7-9 To apply contemporary approaches using genetically engineered mice or translucent zebrafish, genetic phenotypes of metabolic syndrome remain too complex.An animal model of familiar hypercholesterolemia is unique in Watanabe heritable hyperlipidemic (WHHL) rabbit, because it closely resembles cholesterol metabolism in humans. We successfully segregated a hypertriglyceridemic type of WHHL (WHHL-TGH) rabbit, and then established a postprandial hypertriglyceridemic (PHT) rabbit from a cross between a normal Japanese white (JW) rabbit and a WHHL-TGH rabbit. 10 The present study was aimed to clarify the levels of central obesity and glucose intolerance in our newly established animal model of human disease. Materials and Methods AnimalsMale 8-to 16-month-old PHT rabbits (number of rabbits: 19) and 10-to 17-month-old JW rabbits (number of rabbits: 6; Shira...

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The distribution of the antibody to influenza C virus in the dogs and pigs in Yamagata prefecture, Japan was investigated by using three different serological methods: hemagglutination-inhibition (HI), radioimmunoprecipitation (RIP), and immunoblotting. The antibody against influenza C virus glycoprotein (gp88) was detected in 5 out of 112 sera collected from mongrel dogs, three by RIP test and two by any of the three methods, suggesting that the virus can cause natural infection in dogs. Significant levels of HI activity were found in 58 out of 269 sera collected from domestic pigs, but none of them showed positive reaction in the more sensitive method, RIP, which suggests that the inhibitors against the hemagglutination by influenza C virus rather than the antibody to gp88 are responsible for the observed HI activity. It appears, therefore, that at least in the Yamagata area, pigs do not play significant roles in the spread of influenza C virus in humans.

A study was performed to determine if type C influenza infection could be established in dogs as a model for human cases. Mongrel dogs were infected with the Ann Arbor/1/50 strain of type C influenza virus and were examined for clinical symptoms, virus isolation and antibody response. After the first exposure to the virus, all infected animals developed nasal discharge and some of them also showed swelling of the eyelids, and suffusion of the eyes with tears and eye mucus, within 1 to 4 days. The animals showed an increase in hemagglutination-inhibiting (HI) serum antibody, and recovery of the agent from the nasal swabs was successful. The symptoms lasted for as long as 10 days in most infected dogs, which was comparable to our human cases reported previously (Katagiri, S., Ohizumi, A., and Homma, M. 1983. J. Infect. Dis. 48: 51-56). After the second and third virus exposures at intervals of 50 days, all animals developed the same symptoms as those described above and the rise in antibody titer was evident. The virus could be recovered from four of the six dogs 2 to 5 days after the second exposure and from one dog as late as 10 days after the third exposure. Increases in antibody titer in the IgM fraction were observed after every infection. In control dogs which were mock-infected with UV-inactivated virus, no symptoms were evident and recovery of the virus was not successful although an increase in HI serum antibody titer was seen. These results show that mongrel dogs are sensitive to type C influenza virus and that repeated infections characteristic of human influenza C can be experimentally produced in dogs.

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