From an established cell culture line obtained from a chemically-induced rat colon carcinoma, two sublines have been selected and isolated according to their susceptibility to trypsin-mediated detachment from plastic surfaces. Subline TR, the most resistant to the detaching effect of trypsin, gave progressive tumors in most of the syngeneic rats in which it was inoculated. Subline TS, which was easily detached by trypsin, also gave tumors in the syngeneic rats, but all these tumors disappeared within 3 or 4 weeks. Both sublines gave progressive tumors when injected into nude mice. This suggests that the parent cell line is heterogeneous and contains cell variants differing in their susceptibility to trypsin-mediated detachment from substrate and their sensitivity to host factors leading to acceptance or rejection of the inoculated tumor cells.
For the first time in West Africa, arboviruses were isolated from phlebotomine sand fly pools. One strain of Chandipura virus (a Vesiculovirus), four strains of Saboya virus (a Flavivirus), and one strain of a not yet identified virus were isolated. Three hundred twenty-two pools were established from a population of 33,917 sand flies caught in CO, light traps in the Ferlo Sahelian region of Senegal from November 1991 to December 1992. This is the first isolation of Chandipura virus from any arthropod in Africa. Saboya virus has already been isolated from small rodents in Senegal; thus, its transmission cycle probably involves rodentophilic sand flies. No strain of Rift Valley fever phlebovirus, which caused an epizootic in this region in 1987, was isolated. During the same time at the same site, 11 sand fly species were identified from 4,191 specimens caught on sticky traps, including Phlebotomus duboscqi, a leishmaniasis vector.
Determinants of infertility were studied in 340 women in Eastern Gabon, an area situated in the "infertility belt" of Central Africa. Fallopian tube occlusion was diagnosed in 82.8% of cases, showing the importance of infection-related causes. Women with tubal occlusion did not differ significantly from women with normal tubes in obstetrical history or prevalence of Neisseria gonorrhoeae or Chlamydia trachomatis on endocervical culture. Antecedents of pelvic inflammatory disease or a pelvic mass were significantly more common in the group with tubal occlusion. This group also had a significantly higher prevalence of serum chlamydial antibodies at a titer of 1/64 or higher. Hormonal factors were found in 31.7% of women, a cervical factor in 29.0% and mechanical factors in 5.6%. No diagnosis could be made in 12.2% of cases. During the investigation, 4.4% of women became pregnant. The predominance of infectious related causes of infertility makes it imperative to focus resources on prevention programs of upper genital tract infections in women.
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