Philippe Revelard

The genes and transcripts of an antigen gene expression site from T. brucei

The AnTat 1.3A antigen gene expression site of T. brucei was cloned from genomic libraries of the 200 kb expressor chromosome. In addition to the antigen gene, it contains seven putative coding regions (ESAGs, for expression site-associated genes), as well as a RIME retroposon. The polypeptide encoded by ESAG 4 shows homology to yeast adenylate cyclase, and possesses structural features of a transmembrane protein. The expression site is transcribed by a pol l-like polymerase in the parasite bloodstream form only, but sequences similar to ESAGs 5, 4, and 2 are also transcribed constitutively elsewhere, by a polymerase sensitive to alpha-amanitin. Ultraviolet irradiation, which seems to block RNA processing, allows the tentative mapping of a transcription promoter about 45 kb upstream of the antigen gene.

Short-term medical complications of 1500 oocyte retrievals for in vitro fertilization and embryo transfer

OBJECTIVE To evaluate the different short-term complications after in vitro fertilization and embryo transfer. DESIGN a retrospective study on 7 years in the fertility clinic of an university hospital. MATERIALS AND METHODS Short-term medical complications were analysed after 1500 transvaginal ultrasonographically guided oocyte retrievals. RESULTS Ovarian hyperstimulation syndrome (1.8%), pelvic infections (0.4%), intraperitoneal bleeding (0.2%) and adnexal torsions (0.13%) were observed. One case of adnexal torsion occurred during pregnancy (0.18%). Two unusual case of bowel endometriosis were encountered (0.13%). CONCLUSIONS Short-term medical complications after in vitro fertilization and embryo transfer are rare (2.8%). This contrast with the high rate of multifetal pregnancies which increases maternal and perinatal morbidity and mortality and must be considered as the major complication of in vitro fertilization treatment.

Structure and transcription of a P-ATPase gene from Trypanosoma brucei

A putative ATPase gene was cloned from Trypanosoma brucei genomic DNA. The length of the gene open reading frame is 3,033 bp, predicting a protein of about 110 kDa. The sequence of this protein shares 10 blocks of homology with other eukaryotic ATPases, including the putative phosphorylation site characteristic of P-ATPases. Its hydropathy profile reveals 8-10 potential membrane-spanning regions. While the amino acid sequence of the T. brucei ATPase shows only 25% overall homology with its counterpart from the related kinetoplastid protozoan Leishmania donovani, 49% sequence conservation is found when compared with the calcium-ATPase from rabbit sarcoplasmic reticulum. This gene is present in only one copy, localized in the large chromosome fraction. It is transcribed at a similar level in procyclic and bloodstream forms, as a 4.3-kb mRNA. Run-on assays suggest continuous transcription of the gene and flanking sequences over at least 10 kb, by a RNA polymerase sensitive to alpha-amanitin. Transcription inhibition by UV irradiation suggests that the ATPase gene is more than 4 kb downstream from its promoter.

Human cytomegalovirus seroprevalence and risk of seroconversion in a fertility clinic population.

OBJECTIVE: To retrospectively evaluate factors influencing human cytomegalovirus serologic status of couples consulting our fertility clinic. METHODS: Human cytomegalovirus individual serologic status of 3,227 women and 2,565 men was studied according to age, serologic status of the sexual partner, and presence of children in the family at entry in the clinic. Among 1,906 initially seronegative individuals, human cytomegalovirus seroconversions during follow-up were recorded and correlated to age, serologic status of the sexual partner, and presence of children aged younger than 3 years in the family. RESULTS: Human cytomegalovirus status at entry in the fertility clinic depended on age, but women were more frequently seropositive (54%) than men (43%), although they were younger (mean age 33 years for women and 37 years for men). The probability of seroconversion of women and men was significantly associated with the presence of children aged younger than 3 years; 35 of 217 women (16%) and 17 of 130 men (13%) living with children aged younger than 3 years seroconverted compared with 37 of 1,066 women (3.4%) and 16 of 493 men (3.2%) without children. Moreover, women’s seroconversion was significantly associated with the seropositivity of the sex partner; 13 of 96 (13.5%) women with a cytomegalovirus seropositive partner seroconverted compared with 33 of 452 (7.3%) of those without such a partner. CONCLUSION: Our results suggest that human cytomegalovirus is sexually transmitted among couples in our fertility clinic. Safe sex practices should be included in hygiene precaution advice given to pregnant women to avoid human cytomegalovirus contamination. LEVEL OF EVIDENCE: II