A deletion polymorphism due to Alu-Alu recombination in intron 2 of the retinoblastoma gene: association with human gliomas

In past years, much attention has been paid to the HIV-1 envelope (env) protein variable region 3 (V3), termed the principal neutralizing determinant. HIV-1 vaccines were often designed to target V3, and vaccine efficacy was often measured with V3-based assays. Thus, some disappointment resulted when volunteers in first clinical vaccine trials generated V3-specific antibodies that could not protect against V3-similar viruses. We describe an analysis of V1 and V2 sequence effects on antibody binding to V3 and non-V3 determinants. This study involved the preparation of seven full-length (gp160), chimeric env proteins in a vaccinia virus (VV) expression system. Chimeric proteins displayed different V1-V2 sequences but were otherwise identical. A panel of 12 monoclonal antibodies was then tested for binding activities toward the seven chimeras. Results showed that V1-V2 sequences affected antibody binding to env, both in V3 and non-V3 positions. These data demonstrate the enormous complexity of HIV-1 env protein conformation and antigenic determinants. Respect for the complexity of antibody-antigen interactions encourages the design of sophisticated immunoglobulin and protein cocktails for use in HIV-1 therapies and vaccines, respectively.     

Expression of superoxide dismutase and xanthine oxidase in myometrium, fetal membranes and placenta during normal human pregnancy and parturition

Superoxide, an agent which attenuates the half-life of nitric oxide, is metabolized and synthesized by superoxide dismutase (SOD) and xanthine oxidase, respectively. Over the last few years much work has focused on the role of nitric oxide in human parturition. The aim of this study was to determine whether the onset of human parturition is associated with a change in the expression of copper/zinc superoxide dismutase (Cu/Zn SOD), manganese superoxide dismutase (Mn SOD) or xanthine oxidase within the uterus. Samples of myometrium, placenta, decidua and fetal membranes were obtained from women before and after the onset of labour at term. Immunocytochemistry was used to localize Cu/Zn SOD, Mn SOD and xanthine oxidase and measure SOD enzyme activity. Cu/Zn and Mn SOD-like immunoreactivity was detected in syncytiotrophoblast cells, villous stromal cells and endothelial cells of blood vessels in the placenta. In the myometrium Cu/Zn and Mn SOD were localized to myocytes and endothelial cells and to some vascular smooth muscle cells. In the fetal membranes we observed staining for Cu/Zn SOD and Mn SOD in the amnion, chorion, extravillous trophoblast and decidua. There was no difference in SOD enzyme activity or staining intensity for SOD between different cell types before and during labour. Xanthine oxidase immunoreactivity was identified in each of the tissues examined and again there was no difference in immunostaining in tissues obtained from women delivered before or after the onset of labour. These results show that the pregnant uterus is capable of both synthesizing and degrading superoxide and suggest that superoxide dismutase and xanthine oxidase may play a role in the maintenance of uterine quiescence during pregnancy, but not in the initiation of parturition.     

Postprocessing techniques for gadolinium-enhanced three-dimensional MR angiography

Contrast material-enhanced three-dimensional (3D) magnetic resonance (MR) angiography is rapidly gaining acceptance as a versatile noninvasive alternative to conventional angiography. The technique has proved useful in the visualization and assessment of complex pathologic entities in the thoracic and abdominal aorta, renal arteries, pelvic arterial system, and pulmonary arteries. Several postprocessing techniques are available for reformation of the imaging data, including maximum intensity projection (MIP), surface rendering, and virtual intraluminal endoscopy (VIE). MIP and subvolume MIP reconstructions can be produced quickly and are useful for demonstration and archiving purposes. Because of its unique ability to display vessels without overlap, surface rendering is especially useful in depicting diseases that influence either the outer shape of the vessels or their topographic arrangement. VIE allows assessment of the inside of the vascular wall and is helpful in detecting wall-bound thrombus and evaluating the degree of stenosis. Most clinically relevant questions (eg, presence of pulmonary embolism, aortic aneurysm, renal artery stenosis) can be fully answered if analysis is based on MIP and thin multiplanar reformations of contrast-enhanced 3D MR angiograms. In some cases, the use of additional postprocessing techniques enhances diagnostic confidence.