Abstract:The RNA polymerase gene of murine norovirus (MNV) was isolated from feces and organ samples by the reverse transcription (RT)-polymerase chain reaction (PCR). For experimental infection, homogenate of cecum obtained from an MNV-infected mouse was gavaged to 3 C.B-17-Prkdc scid (scid) mice and 3 ICR mice at 6 weeks of age. Sixty days after oral inoculation, MNV was isolated from the cecum (3/3 scid and 3/3 ICR), feces (3/3 scid and 3/3 ICR), duodenum (1/3 scid and 3/3 ICR), liver (1/3 scid and 1/3 ICR), and spleen (3/3 ICR) samples, but MNV was not detected in the brain, heart, kidney, lung, salivary gland, ovary, thymus, or uterus samples of any of the orally inoculated mice. Feces of males cohabiting with MNV infected dams were positive for viral RNA after 18 days of cohabitation, but 8 fetuses (embryonic day 18.0) derived from the dams were negative for the virus. The results suggest that the cecum and feces are the most suitable sample types for the detection of MNV in infected animals and that caesarean section is efficient for the elimination of the virus. In terms of spontaneous infection, the RNA polymerase gene of MNV was isolated from 33/245 (13.1%) cecum samples derived from 15/59 (25.4%) facilities, and the sequence analysis revealed that at least 5 types of the virus were prevalent. This is the first report on MNV infection in mouse colonies in Japan.

Abstract:On the basis of our 2011 microbiological monitoring tests, we report here the current microbiological status of mice and rats housed in experimental facilities in Japan. We tested more than 14,000 mice, 6,000 serum samples, 500 fecal or cecal samples, and 200 lung samples from 3,549 mouse facilities within Japanese universities and institutes (U/I), pharmaceutical companies and contract research organizations (P/C). We also tested more than 1,500 rats, 1,600 serum samples, and 20 fecal or cecal samples from 772 U/I and P/C rat facilities. Bacterial cultures, serology, microscopy, PCR, and DNA analysis using DNA chips were performed. Staphylococcus aureus (18.8% in mouse facilities, 58.6% in rat facilities) was the most prevalent agent in both the mouse and rat facilities. The next most prevalent agents in the mouse facilities were murine norovirus (11.97%), intestinal protozoa (0.05-8.49%, from various species), Pasteurella pneumotropica (5.32%), and Helicobacter hepaticus (3.17%), while intestinal protozoa (0.74-6.84% from various species), Syphacia muris (6.20%), Pseudomonas aeruginosa (3.61%), and Pasteurella pneumotropica (3.05%) were the subsequent most prevalent agents in the rat facilities. These results suggest that the currently prevalent microbes in laboratory mice and rats in Japan are mainly opportunistic pathogens, intestinal protozoa, and microbes with low pathogenicity.

We performed HLA-A, -B, and -C antigen and -DR DNA typing in 111 Japanese patients with idiopathic thrombocytopenic purpura (ITP). DRB1*0410 was significantly increased in ITP patients compared with healthy controls (relative risk = 9.52, P < .05), but the other DRB1*04 alleles showed no significant differences. On HLA-DR serotyping, patients with Vogt-Koyanagi-Harada disease (VKH) had a high frequency of DR4, so we compared the frequencies of DRB1*04 suballeles between ITP and VKH. The high frequency of DRB1*04 was dependent on DRB1*0405 in VKH, but on DRB1*0410 in ITP. Plasma autoantibodies were studied in 111 patients using a microtiter well assay. Thirty-six patients had anti-GPIIb/IIIa autoantibodies, and antibody positivity was associated with HLA-DR4 (29 of 36, 80.6% v 28 of 75, 37.3%) but not with DRB1*0410. When HLA-DR4 and DRB1*0410 were compared between patients with a good or poor response to prednisolone, HLA-DR4 was decreased and DRB1*0410 was significantly decreased (χ2 = 11.455, P < .01) in patients with a good response. In conclusion, this study showed that genetically determined factors influence the course of ITP. However, our findings should be considered preliminary because of possible racial differences in HLA status between Japanese and other ITP patients.

The levels of interleukin-6 and platelet-derived microparticles (PMPs) were measured in the blood of 137 patients with side effects from platelet concentrate (PC) transfusion with leukocyte removal filtration, P-selectin-expressing platelet and PMPs in stored PC before and after the filtration, and filtered leukocytes positive for P-selectin glycoprotein ligand-1. The side effects, which were observed in 203 transfusions for 84 patients with hematologic disease and 53 patients with nonhematologic disease with no significant difference between the two groups, included urticaria (75.9%), erythema (18.7%), and fever (17.2%), but no anaphylactic reactions. The levels of interleukin-6 and PMP correlated in both groups, and were significantly higher in the hematologic disease group than in the nonhematologic disease group. The level of PMP, but not interleukin-6, was significantly higher for patients testing positive for allergic reaction than for those testing negative. In the stored PC prior to filtration, the level of interleukin-6 was normal. The level of P-selectin-expressing platelets and PMPs was elevated before filtration, but was significantly lower after filtration. Taken together, the results suggest that PMP is involved in the generation of transfusion reactions, and indicate that both platelets and PMP displaying P-selectin bind to P-selectin glycoprotein ligand-1 of leukocytes retained by the leukocyte filter.

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