We previously reported the establishment of several lymphoid cell lines from Xray-induced thymomas of C57BL/Ka mice, and all, except one, produce retroviruses (P. Sankar-Mistry and P. Jolicoeur, J. Virol.35:270-275, 1980). Biological characterization offive of these new primary radiation leukemia viruses (RadLVs) indicated that they had a B-tropic, fibrotropic, and ecotropic host range and were leukemogenic when reinjected into C57BL/Ka newborn mice. The leukemogenic potential of one isolate (G6T2) was further assessed and shown to be retained after prolonged passaging on fibroblasts in vitro. Restriction endonuclease analysis of the DNA of four of our new RadLV isolates (G6T2, Ti-7, Ti-8, and Ti-9) revealed

Bacillus cereus is responsible for an increasing number of food poisoning cases. By using 12 bacteriophages isolated from sewage, a typing scheme for B. cereus isolates from outbreaks or sporadic cases of food poisoning was developed. The phages belonged to three morphotypes. Ten phages with contractile tails and icosahedral heads were members of the Myoviridae family, and two phages with noncontractile tails belonged to the Siphoviridae family. Phage 11 represented a new species. It had an isometric head and a very long contractile tail with long wavy tail fibers and was one of the largest viruses known. The vast majority of 166 B. cereus strains (161, or 97%) isolated from food poisoning cases were typeable. Of 146 strains isolated from 18 outbreaks, 142 (97%) could be divided into 17 phage types. A good correlation, on the order of 80 to 100%, between phage types of strains isolated from suspected foods and those of strains isolated from stools of symptomatic patients was observed. Most Bacillus thuringiensis strains were also typeable, providing further evidence of the close relatedness of B. cereus and B. thuringiensis. This phage typing scheme can be a valuable epidemiological tool in tracing the origins of food poisoning caused by B. cereus.

Fractionated whole-body X irradiation of C57BL/Ka mice leads to the development of thymic leukemia in 90% of the treated animals at an average age of 6 months. Using a sensitive high-density cocultivation procedure, we were able to demonstrate the presence of ecotropic murine leukemia virus (MuLV) from 1 month post-irradiation up to leukemia development. These viruses are not specific to any one particular organ, but can be found in at least two of the three lymphoreticular tissues studied, namely, spleen, thymus, and bone marrow. Host range studies on the isolated viruses showed that both N- and B-tropic MuLV could be isolated early after irradiation. However, as mice reached an age where leukemias develop, only the B-tropic MuLV could be recovered. We have established cell lines from primary radiation-induced tumors that are being maintained in continuous culture: except one cell line, all are virus producers. The results clearly indicate that X irradiation induces ecotropic MuLV in C57BL/Ka mice and suggest that B-tropic MuLV might be involved in the disease process.

The early diagnosis of human rotavirus infection is essential for effective patient management and infection control. We report here a rapid, easy-to-perform, and inexpensive test for rotavirus detection. The viral RNA is extracted directly from the stools and electrophoresed on 1% agarose gels. Currently available immunoassays for routine diagnostic purposes are directed at the common group A-specific antigen. As reports become available on human gastroenteritis caused by the atypical or novel rotaviruses, this technique presents an added advantage in that it can detect both group A and non-group A rotaviruses.

Objective The aim of the present study was to examine the association between infection with Chlamydia pneumoniae and symptomatic atherosclerosis in peritoneal dialysis (PD) patients. Design Cross-sectional study. Setting Peritoneal Dialysis Unit of Kingston General Hospital. Patients Fifty-five prevalent PD patients. Outcome Measures ( 1 ) Infection with C. pneumoniae diagnosed by detection of DNA in peripheral blood mono-nuclear cells (PBMCs) using polymerase chain reaction. ( 2 ) Symptomatic atherosclerosis involving the coronary, cerebral, or peripheral circulation. Results The DNA of C. pneumoniae was detected in PBMCs in 33 patients (60.0%). Atherosclerosis was present in 16 of 33 (48%) PBMC C. pneumoniae DNA–positive patients, and in 10 of 22 (45%) PBMC C. pneumoniae DNA–negative patients ( p = 0.83). Using multiple logistic regression and controlling for a number of known cardiovascular risk factors, PBMC C. pneumoniae DNA status was not predictive of atherosclerosis. The only significant independent predictors of atherosclerosis were diabetes and age. Conclusions In prevalent PD patients, a high prevalence of symptomatic atherosclerosis and of Chlamydia pneumoniae DNA in PBMCs were seen; however, the results of the present study do not support the presence of an association between infection with C. pneumoniae and atherosclerosis.