Molecular diagnosis of Down syndrome using quantitative APEX-2 microarrays.

Objective: To develop a new rapid and high-throughput microarray-based prenatal diagnostic test for the detection of trisomy 21 (T21).

Methods: The T21 arrayed primer extension-2 (APEX-2) assay discriminates between trisomy and euploid DNA samples by comparing the signal intensities of allelic fractions of heterozygous single nucleotide polymorphisms (SNPs) after APEX reaction. After preliminary validation using DNA samples from Down syndrome patients, we analyzed DNA samples from cultured and uncultured amniocytes and chorionic villus for 90 SNPs with high heterozygosity from the 21(q21.

Out-of-hospital resuscitation in Estonia: a bystander-witnessed sudden cardiac arrest.

Objective: To evaluate the results of the first epidemiological study on out-of-hospital resuscitation in Estonia.

Methods: A prospective cohort study of 2108 consecutive standardized reports on out-of-hospital resuscitation attempts from 1 January 1999 to 31 December 2002 was conducted according to the Utstein style.

Results: In all, 67.