Objective To compare procedure-related pregnancy loss after second-trimester genetic amniocentesis in women given an antibiotic prophylaxis and controls.Methods Prospective, open randomised controlled single-centre study between January 1999 and December 2005 at Artemisia Fetal Maternal Medical Centre. A follow-up within 4 weeks after the procedure was done.Of 36 347 eligible women, 1424 refused to participate and 34 923 were enrolled and randomised with unequal chance of selection, 21 991 were assigned to treatment group and 12 932 were assigned to the control group, and did not receive any placebo. Oral azithromycin, 500 mg per day, was administered 3 days before amniocentesis. The primary endpoint was the procedure-related pregnancy loss. The secondary endpoint was the rate of preterm premature rupture of membranes. ResultsThe rate of abortion related to the amniocentesis was 7/21 219 women (0.03%, 95% CI 0.009-0.057) in the intervention group, and 36/12 529 (0.28%, 0.28-0.30) in controls (p = 0.0019). The rate of preterm premature rupture of membranes was 14/21 219 (0.06%, 0.031-0.101) in the intervention group, and 140/12 529 (1.12%, 0.94-1.30) in the control group (p = 0.001).Conclusions Antibiotic prophylaxis before second-trimester amniocentesis reduced the risk of abortion and of rupture of the membranes.

The distribution of the (TTAGGG)n telomeric sequence in Danio rerio (zebrafish) metaphase chromosomes was studied by fluorescence in situ hybridization. This study continues the analysis of the telomeric sequence distribution in fish and confirms that the (TTAGGG)n sequence is conserved in the telomeres of this group of vertebrates. The hybridization signals were restricted to telomeres in all the individuals analysed. With the degree of resolution currently available, no interstitial sites of the telomeric sequence were detected, which suggests that this type of hot-spot recombination site might be absent in zebrafish chromosomes.

This study provides new data on zebrafish chromosomes, obtained from the chromomycin A3-banding pattern and mapping of 18S rRNA genes by fluorescence in situ hybridization (FISH). C-banding and Agstaining were also performed to analyse whether variation in heterochromatin and Ag-nucleolus organizer regions (NORs) exists among various commercially purchased strains. The results provide information on heterochromatin composition and on the existence of interindividual NOR polymorphism and contribute to the construction of an idiogram suitable for gene mapping.

New molecular cytogenetic techniques array comparative genomic hybridization and fluorescence in-situ hybridization in association with conventional karyotype are pivotal innovative tools to search for chromosomic anomalies and for a complete prenatal diagnosis, especially in cases such as PKS where array comparative genomic hybridization analysis alone could not show mosaicism of i(12p).

This study has been useful in supporting the probable connection between climate changes and viral evolution also by the vector point of view; multidisciplinary monitoring studies are important to prevent new viral epidemics inside and outside new endemic areas.