Effects of age on hemodynamic changes after transcatheter closure of atrial septal defect: importance of ventricular diastolic function

Some older patients develop symptoms of clinical heart failure after closure of an atrial septal defect (ASD). The present study tested the hypothesis that baseline hemodynamics and hemodynamic changes induced by transcatheter ASD closure are different between younger and older patients due to age-related differences in left ventricular (LV) diastolic dysfunction. Forty-three consecutive patients (27.7 ± 16.3 years of age, range 5–63, median 25) who underwent device closure for ASD were divided into younger (age ≤25, n = 24, 15.1 ± 1.2 years) and older (> 25 years, n = 19, 43.7 ± 2.2 years) groups. Echocardiographic evaluations were performed 1 day before and 2 days after ASD closure. Before ASD repair, early diastolic mitral annular velocity (e′) on lateral, an index of ventricular relaxation, showed an age-related decrease. After closure, e′ decreased by similar amount in both groups (p < 0.05). In addition, E/e′, an index of LV filling pressure, was relatively unchanged in the younger group (from 5.4 to 5.9) but significantly increased (p < 0.05) in the older group (from 6.3 to 8.1) over similar increase of normalized LV diastolic dimension. In older patients, ASD closure resulted in further deterioration of baseline impairment in LV relaxation and the increased LV stiffness caused a more marked rise in LV filling pressure, compared to the younger group. Thus, ASD should be closed at a younger age before the development of age-related LV diastolic dysfunction.     

The hematopoietic cell-specific Rho GTPase inhibitor ARHGDIB/D4GDI limits HIV type 1 replication

Rho GTPases are able to influence the replication of human immunodeficiency virus type 1 (HIV-1). However, little is known about the regulation of HIV-1 replication by guanine nucleotide dissociation inhibitors (GDIs), one of the three major regulators of the Rho GTPase activation cycle. From a T cell-based cDNA library screening, ARHGDIB/RhoGDIβ, a hematopoietic lineage-specific GDI family protein, was identified as a negative regulator of HIV-1 replication. Up-regulation of ARHGDIB attenuated the replication of HIV-1 in multiple T cell lines. The results showed that (1) a significant portion of RhoA and Rac1, but not Cdc42, exists in the GTP-bound active form under steady-state conditions, (2) ectopic ARHGDIB expression reduced the F-actin content and the active forms of both RhoA and Rac1, and (3) HIV-1 infection was attenuated by either ectopic expression of ARHGDIB or inhibition of the RhoA signal cascade at the HIV-1 Env-dependent early phase of the viral life cycle. This is in good agreement with the previous finding that RhoA and Rac1 promote HIV-1 entry by increasing the efficiency of receptor clustering and virus-cell membrane fusion. In conclusion, the ARHGDIB is a lymphoid-specific intrinsic negative regulator of HIV-1 replication that acts by simultaneously inhibiting RhoA and Rac1 functions.     

Extraperitoneal colostomy in laparoscopic abdominoperineal resection using a laparoscopic retractor

Although extraperitoneal colostomy is often performed to prevent postoperative parastomal hernia formation following an open abdominoperineal resection of lower rectal cancer, it has not been widely employed laparoscopically because of the difficulty associated with the extraperitoneal route. This paper describes a laparoscopic extraperitoneal sigmoid colostomy using the Endo Retract? Maxi instrument. This surgical technique is easy, and helps to prevent the development of parastomal hernias.