The aetiology of Crohn's disease remains unknown, although evidence for a viral cause has long been sought. Recent studies have shown inflammation of the submucosal microvascular endothelium and granulomata, and endothelial cell cytoplasmic inclusions, consistent with paramyxovirus, were identified by electron microscopy suggesting a persistent measles virus infection in Crohn's disease. Measles, mumps, and rubella viruses were tested for Crohn's disease by polymerase chain reaction (PCR). RNA was extracted from resected intestinal specimens from 15 patients with Crohn's disease, 14 with ulcerative colitis, and 14 controls without inflammatory bowel disease. This was used to perform nested PCR after reverse transcription (RT) of the RNA to cDNA with primer pairs directed against two regions in the genome of the measles virus and one region in the mumps and rubella viral genomes. Despite enhanced sensitivity of nested RT-PCR, measles, mumps, and rubella viral genomic sequences were not found in any intestinal specimen.

AND R . KUSUDA. 1996. Lastonella (Vibrio) anguillarum, an important fish pathogen, is divided into 10 serotypes according to O-antigens present on the outer membrane. However, the biochemical and immunological properties of porin proteins have not been reported. In this study, the antigenicity and N-terminal amino acid sequence of the 35 kDa porin-like-major outer membrane protein (Omp35La) were compared among different serotypes of L. anguillarum as well as other bacteria. In Western blotting analysis, antisera against Omp35La from strains of J-0-1, -2 and -3 serotypes could detect Omp35La, but not other proteins, in most L. anguillarum strains and isolates of the genera Vibrio and Photobacterium. This antigenicity of Omp35La is unrelated to the serotype and is conserved in related organisms. An N-terminal sequence showed identification with OmpF and OmpC of Escherichia coli and Salmonella typhimurium. However, this similarity was lower when compared to other human pathogens. Thus it was concluded that Omp35La does not contribute to the serotypes of L. anguillarum, although the N-terminal structure is well conserved among different serotypes.

Rabbit colitis has been induced by injection of muramyl dipeptide emulsified with a long-chain fatty acid. The muramyl dipeptide emulsion was injected submucosally at six portions of the rectum and colon, 10 cm proximal to the anus, using a flexible endoscope. Six rabbits were injected six times every 2 weeks and subsequently killed 2 weeks after the last injection. The histological changes of the colon that occurred in all 6 rabbits were mononuclear cell and histiocyte infiltration with sporadic eosinophils, transmural infiltration, and well-maintained goblet cell populations. These changes were different in degree. In 4 of 6 rabbits histological examination of the liver showed pericholangitis and periductal fibrosis mimicking the pericholangitis frequently seen in patients with inflammatory bowel disease. Fibrosis bridging between the portal and portal veins occurred in 2 rabbits, and noncaseating granuloma was seen in 1 rabbit. These histological changes in our model have led to the suggestion that continuous stimulation with bacterial cell wall fragments may be involved in chronic intestinal inflammation and extraintestinal manifestations such as pericholangitis.

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We examined whether extraintestinal manifestations of granulomatous enterocolitis in rabbits might be produced by the long-term administration of muramyl dipeptide which represents the basic fragment of the bacterial cell wall, emulsified with Freund's incomplete adjuvant. Muramyl dipeptide emulsion was injected submucosally at six sites in the rectum and colon, 10 cm proximal to the anus, each time with a flexible endoscope. Seven rabbits were injected nine times or more every month, and all were sacrificed 1 month after the last injection. The histological changes in the colon in the seven rabbits were mononuclear cell infiltration, epithelioid granulomas, granulomatous lesion, and denuded and regenerative epithelia, although the changes differed in degree. In five of the seven rabbits, histological examination of the liver showed pericholangitis and periductal fibrosis, findings analogous to sclerosing cholangitis in patients with inflammatory bowel disease. In four of the seven rabbits, fibrosis bridging mainly between portal and portal veins, and, in places, between portal and central veins, was seen. Two of the seven rabbits developed polyarthritis. The histological changes in our model suggest that continuous stimulation with bacterial cell wall fragments may be involved in the extraintestinal manifestations of chronic intestinal inflammation such as that seen in inflammatory bowel disease.