DNA sequence analysis and Jk blood group genotype-phenotype assessment.

BACKGROUND: The Kidd (JK) blood group is critical for clinical blood transfusion. Various methods for Jk typing have been commonly used, including urea hemolysis, serological test, and genotyping. However, the application of molecular methods has so far been restricted to selected samples and not been applied to the population-scale analysis. METHODS: One hundred eighty-three blood samples, containing 174 samples collected from voluntary blood donors of Chinese Han individuals, together with 3 Jk (aw+b-) and 6 Jk (a-b-) samples, were investigated by standard serology urea hemolysis test and Sanger-sequencing. Complete coverage of exons 4-11 and intron-exon borders have been sequenced. RESULTS: We report the frequencies of three SNPs in exon 4, 7, and intron 9. Besides, sequence analysis revealed the simultaneous DNA variants of intron 7 (-68) and exon 9 (838) found in all samples, suggesting the co-inheritance of these SNPs-taking the observed SNPs frequencies into account. Further, we discuss the potential of the sequencing technique for high-resolution genotyping. CONCLUSIONS: The described sequencing method for Jk exons delivers a genotyping technique for Jk molecular characterization. According to the co-inheritance of these DNA variants in intron 7 (-68) and exon 9 (838), and their regularity linkage with Jk phenotypes, these two sites offer a potential sequencing target for rapid and far more simplified Jk typing that can supplement routine serology and urea hemolysis tests.

A mortality risk assessment model for cardiac valve replacement surgery and its application in the use of prophylactic extracorporeal membrane oxygenation.

This study was conducted to establish a quantitative model to predict the risk of in-hospital mortality for patients undergoing cardiac valve replacement and to decrease mortality in patients with predicted high risk using prophylactic extracorporeal membrane oxygenation (PECMO). We retrospectively reviewed the medical records of 4482 patients who underwent cardiac valve replacement from January 1994 to December 2004, at Anzhen Hospital, Beijing, China. A total of 158 patients were going to receive heart valve replacement. Associations between mortality and the demographic, clinical, and laboratory variables of patients were first assessed using univariate analysis. Six of 7 variables in the univariate analysis were statistically significant and were included in the multivariate analysis: renal function; age; left ventricular ejection fraction (EF); coronary artery disease (CAD); pulmonary artery pressure (PAP); and left ventricular end-diastolic diameter (LVEDD). The area under the receiver operating characteristic (ROC) curve (AUC) was 73.58%. Observed mortality in the group with PECMO (5.45%, 3/55) was significantly lower (Pearson Chi2 = 4.314, P = 0.038, P < 0.05) than in the group without PECMO (24.27%, 25/103). With the use of our scoring model, the risk of postoperative mortality in patients planning to undergo valve replacement can be predicted before the procedure is performed. For patients with predicted mortality greater than 10%, the use of PECMO during surgery, in addition to extracorporeal circulation, was found to decrease mortality.