The mouse alpha-globin locus regulatory element

We have identified and cloned the major alpha globin locus regulatory element in the mouse (m alpha RE). This element shows a high level of sequence homology to its human counterpart (HS -40) and lies between the same two exons of an upstream, widely expressed gene in both species. Footprinting and band shift studies of the core element show conservation of many (but not all) of the protein binding sites identified as functionally important in HS -40. The functional equivalence of the mouse element was shown by attaching it to a human alpha globin gene and examining expression in transgenic mice. Readily detectable levels of human alpha mRNA were produced in these mice but they were lower than the endogenous gene expression and did not show copy number dependence. These results suggest that sequences additional to this major regulatory element may be necessary to obtain complete regulation of the alpha globin genes in both species.     

Targeted inactivation of the major positive regulatory element (HS-40) of the human alpha-globin gene locus

We have examined the role of the major positive upstream regulatory element of the human alpha-globin gene locus (HS-40) in its natural chromosomal context. Using homologous recombination, HS-40 was replaced by a neo marker gene in a mouse erythroleukemia hybrid cell line containing a single copy of human chromosome 16. In clones from which HS-40 had been deleted, human alpha-globin gene expression was severely reduced, although basal levels of alpha 1 and alpha 2-globin mRNA expression representing less than 3% of the level in control cell lines were detected. Deletion of the neo marker gene, by using FLP recombinase/FLP recombinase target system, proved that the phenotype observed was not caused by the regulatory elements of this marker gene. In the targeted clones, deletion of HS-40 apparently does not affect long-range or local chromatin structure at the alpha promoters. Therefore, these results indicate that, in the experimental system used, HS-40 behaves as a strong inducible enhancer of human alpha- globin gene expression.     

A comparative study of Cardi‐O‐Fix septal occluder versus Amplatzer septal occluder in percutaneous closure of secundum atrial septal defects

Aim: We sought to investigate the safety and efficacy of Cardio‐O‐Fix septal occluder (CSO) in percutaneous closure of atrial septal defects (ASD) as compared to the Amplatzer septal occluder (ASO). Methods: A consecutive of 351 patients received transcatheter ASD closure with CSO or ASO from July 2004 to October 2010 were studied. The ASDs were divided into simple‐ (isolated defects <26 mm) or complex‐types (isolated defect ≥26 mm, double or multifenestrated defects). The procedures were guided by fluoroscopy and transthoracic or transesophageal echocardiography. Clinical and echocardiographic follow‐ups were arranged before discharge, at 1 month and then every 6‐month after implantation. Results: During the study period, 185 (125 males, aged 18.5 ± 15.6 years) and 166 (103 males, aged 21.0 ± 15.7 years) patients attempted CSO and ASO implants, respectively. The CSO group had similar ASD and device sizes, prevalence of complex lesions (17 vs. 16%, P = 0.796), procedural times and success rates (97% vs. 96%, P = 0.635) as compared to the ASO group. Acute residual shunts were less prevalent in CSO than ASO group and most shunts closed spontaneously at 6‐month follow‐ups. The average equipment cost per patient was lower in CSO group (US$ 4,100 vs. US$ 5,900, P < 0.001). The prevalence of device embolization and atrial arrhythmia (all <2%) were similar in both patient groups. Conclusion: Transcatheter ASD occlusion with CSO is safe and effective and it appeared to be an attractive alternative to ASO in closing simple‐type ASD because of its relatively low cost. © 2013 Wiley Periodicals, Inc.     

Polymorphism of adhesion molecule CD31 is not a significant risk factor for graft-versus-host disease

Mismatch between bone marrow transplant (BMT) patient and donor for an amino acid polymorphism within the adhesion molecule CD31 has recently been reported to increase risk for the development of graft-versus-host disease (GVHD). We further examined this association in a larger series of 301 BMT patients (227 with grade III/IV GVHD and 74 with grade 0 GVHD) and their HLA-identical sibling donors. CD31 genotypes were determined by polymerase chain reaction and restriction endonuclease digestion. The role of mismatch at the CD31 locus in the development of GVHD was assessed by analyzing the extent of CD31 identity and CD31 compatibility among the grade 0 GVHD and grade III/IV GVHD sibling pairs. No significant association between CD31 mismatch and the development of severe GVHD was detected in our overall patient population. Sixty-three percent of grade III/IV GVHD sibling pairs and 69% of grade 0 GVHD sibling pairs had CD31 genotypes that were identical (P = .36, odds ratio = 1.30). In addition, neither the grade 0 GVHD group (P = .10) nor the grade III/IV GVHD group (P = .27) differed significantly from the expected probability of identity between sibling pairs. Mismatch at the CD31 polymorphism between recipients and donors showed no consistent association with the development of GVHD. Current evidence does not support the value of CD31 mismatch in the selection of BMT donors.