Pneumocystis carinii is an opportunistic agent found in the lung of various mammals which often causes severe pneumonia in immunocompromised humans, especially in AIDS patients. In the past several years significant additions have been made to the collection of knowledge we have concerning the genetic diversity of P. carinii. These additions provide new understanding of Pneumocystis transmission and the effect of possible reservoirs of Pneumocystis in the various species. In this study, a 400-bp fragment of the thymidylate synthase (TS) gene of P. carinii has been amplified by PCR from 43 parasite isolates obtained from 4 mammalian host species: rat, mouse, rabbit and human. A probe selected from the TS gene sequence of rat-derived P. carinii was hybridized with the amplified products from rat- and mouse-derived P. carinii, but not with rabbit or human P. carinii DNA. Restriction profiles were performed on amplified fragments from all isolates, and the 4 nucleotide sequences of the TS gene fragment amplified from rat, mouse, rabbit and human P. carinii were determined. Differences were detected in the gene fragment in P. carinii isolates from the 4 host species; however no difference was revealed in P. carinii isolates within a single host species, whatever the host strain or its geographic origin. Thus, the sequence differences of the P. carinii TS gene appeared as host-species specific. A specific probe which recognized all human P. carinii isolates was defined.

Amino Acid Sequence↗

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[The influence of anhydrobiosis on the infestation of Biomphalaria glabrata by Schistosoma mansoni miracidium].

410 Biomphalaria glabrata (Caribbean strain of Guadeloupe) have been infected with one miracidium of Schistosoma mansoni, 110 snails, used as controls have been kept into water; the survival rate was 96.4% after 4 weeks and 25.4% produced cercariae. 300 snails were kept on wet soil, and submitted for 6 weeks to progressive desiccation. The survival rate was 23.4% but only 9 of them produced cercariae. Periodic variations of the production of male and female larvae have been shown by the weekly test of the cercariae productions. In previously desiccated snails, the production of male and female cercariae is similar while in controls the production of female larvae is more important. In experimental snails, the larval development seems to be stopped during anhydrobiosis. The production of cercariae is just delayed for the length of the dry keeping.

Animals↗

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[Resistance to desiccation of Biomphalaria glabrata adults infested by various miracidia of Schistosoma mansoni].

1200 adult Biomphalaria glabrata were submitted during 6 weeks to anhydrobiosis condition. Some snails were healthy, some were previously infected 3 days or 12 days ago with 8 +/- 2 miracidia of Schistosoma mansoni, others were shedding cercariae. The snails were put on soil or buried into hermetically closed, or ventilated, plastic boxes. There was no survival of snails kept in sealed boxes, or among positive snails, but 44% of control healthy snails and 40.6% of infected (for 3 or 12 days) snails in ventilated boxes were living at the term of the desiccation stage. Survival was better for "on soil" snails than for "buried" snails, but no difference was shown between 3-days and 12-days infection. The surviving desiccated B. glabrata had a lesser death rate and a lesser cercarial production than infected snails kept in water. An inferior production of male cercariae comparatively to female and to "mixed" cercariae was demonstrated by statistical analysis of the cercarial sheddings. In all positive snails, periodic variations of cercarial production was shown, whatever the sex of those cercariae. In addition many pauses of the sheddings were established by the authors.

Animals↗

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[Pharmacodynamic half-life of KO 1366 administered by intravenous and oral route. Comparison with propranolol].

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Administration, Oral↗

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[Sero-immunological research by immunofluorescence of rats bilharziosis in Guandeloupe. Epidemiological interest, comparative studies in various biotopes (author's transl)].

A sero-immunological survey by immunofluorescnece has been conducted on 94 rats (R. rattus and R. norvegicus) captured in Guadeloupe, in there different biotopes where the presence of S. mansoni carriers had been reported. These biotopes are those of the "Grand Etang" (Great Pond), the fresh-water mangrove and its back-mangrove area, and the Beaugendre valley. The post-mortem performed on the rats revealed that 92 % of those carrying. S. mansoni eggs of full-grown worms, had a rate of antibodies superior to 40. The rates of antibodies obtained, as well as the percentages of S. mansoni-parasited rats vary according to the biotopes. Two hypotheses can account for these variations: a smaller or greater adaptation of the S. mansoni stock to the rat; a change in the comportment of rats which would thus be more or exposed to reinfestations.

Animals↗

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