Expression of the Human Immunoglobulin Heavy Chain VH6 Gene Element by Fetal B Lymphocytes

Fetal B lymphocytes in mice and humans use a limited number of the available V_H gene segments. Mouse fetal B cells primarily utilize 3' V_H elements, suggesting that the localization of these elements determines their rearrangement frequency. The previously reported non-random usage of human V_H genes has been more difficult to explain. In this study the authors analysed the expression of the most proximal 3' human V_H element (V_H6) using a monoclonal antibody (JE-6). V_H6 expression was assessed in various B cell differentiation stages from fetal liver, bone marrow and spleen at 12–20 weeks of gestation. The authors demonstrate that the level of V_H6 expression does not exceed a stochastic usage frequency. This suggests that the localization of V_H6 does not significantly promote its expression during human fetal life, and that other factors must affect the usage of V_H genes during human fetal development.     

Accessory left-ventricular chorda and the early ventricular repolarization syndrome

Electrocardiographic symptoms were evaluated in 53 patients with an additional left-ventricular chorda (ALVC), detected by two-dimensional echocardiography. Signs of early ventricular repolarization (EVR) were identified in 45 (84.9%) patients. A transverse ALVC was more common in EVR-free patients (87.5%), as compared to patients with ALVC + EVR combinations (51.1%; p less than 0.05).