Volumetric rendering techniques: applications for three-dimensional imaging of the hip

Volumetric rendering is a new approach to three-dimensional (3D) imaging that overcomes many of the drawbacks of currently available surface-rendering systems. Its application on the Pixar Imaging System in two cases of acetabular fracture was assessed to illustrate the features of the technique. The fast-computing architecture and large memory of this system allow rapid generation of a series of high-quality 3D images in each plane of rotation (x or spinal axis, z or somersaulting axis) that can be viewed as independent static images or as an animated real-time video loop. Editing to remove the normal contralateral hemipelvis enhances appreciation of acetabular abnormalities. Every pixel of computed tomographic data is preserved, allowing representation of both soft tissue and bone as translucent overlap. The presentation of data also allows detection of subtle abnormalities and features and minimizes the artifact generation common in surface-rendered images.     

CD80 expression is decreased in hyperplastic lymph nodes of HIV+ patients

A centrofollicular hyperplasia is present within secondary lymphoid organs during all the asymptomatic phase of the HIV disease. Although this hyperplasia has been well characterized by histological studies, the nature of the phenotypic alterations in B cell populations occurring within HIV+ lymphoid organs remains to be established. By immunohistochemistry, we thus investigated whether a particular germinal center (GC) B cell population was increased during HIV-induced hyperplasia and whether any phenotypic change was specific to HIV-1 infection. As compared to normal tonsils (three cases) and HIV- hyperplastic lymph nodes (eight patients), we observed a loss of GC polarization in all HIV+ sections (11 patients), with no more delineation between dark and light zones, as shown by Ki67, CD10, CD77, CD95 and CD86 staining. In contrast to CD86 expression which remained as intensive in HIV+ as in HIV- lymph nodes, CD80 staining was strongly decreased in GC of HIV+ lymph nodes but not in their extrafollicular zones. The loss of CD80 expression from CD19+ B cells was also observed by cytometric analysis of cell suspensions of three HIV+ patients. Although we found no evidence of an increase in a particular GC B cell subset in HIV-1-induced hyperplasia, the strong GC disorganization observed may induce impaired cell-cell interactions and thus participate in the loss of CD80 antigen. In contrast to HIV- situations where CD80 and CD86 was similarly expressed on B cells, the lower level of CD80 expression in HIV+ GC may favor Th2 T cell responses through CD86-CD28 interactions.      

ES2, a gene deleted in DiGeorge syndrome, encodes a nuclear protein and is expressed during early mouse development, where it shares an expression domain with a Goosecoid-like gene

ES2 is a gene deleted in DiGeorge syndrome (DGS) and velocardiofacial syndrome (VCFS) which has homologs in species as distant as Caenorhabditis elegans and Drosophila . The function of ES2 is unknown, and the predicted protein sequence does not contain motifs which suggest a particular role in the developmental defects present in DGS and VCFS. Here we show that the mouse homolog, Es2 , is transcribed in two forms resulting from the use of alternative polyadenylation signals. Structural analysis programs predict that the Es2 -encoded peptide has a coiled-coil domain, and transfection experiments with an Es2 -green fluorescent protein (GFP) fusion construct show that the peptide is recruited into the nucleus. Es2 is highly expressed during mouse embryogenesis from E7 onwards. In situ hybridization with an RNA probe revealed that the gene is widely expressed; however, relatively higher expression was detected in the nervous system, with a particularly high area of expression in a sub-region of the pons. The Es2 expression domain in the pons is shared with a Goosecoid-like gene ( Gscl) which is located upstream of Es2 , and raises the possibility that the two genes share regulatory elements and/or interact in this region of the developing brain. This finding suggests that different genes in the deleted region may be functionally related and might explain the occurrence of the characteristic phenotype in patients with non-overlapping genetic lesions.      

RELAXATION OF RABBIT MIDDLE CEREBRAL ARTERIES IN VITRO BY H1 HISTAMINERGIC AGONISTS IS INHIBITED BY INDOMETHACIN AND TRANYLCYPROMINE

The H1-histaminergic agonists 2-pyridylethylamine (2-PEA) and 2-methylhistamine relaxed potassium-constricted, perfused, rabbit middle cerebral arteries at low concentrations (3 x 10(-11) to 3 x 10(-8) M) and constricted them at high concentrations (3 x 10(-7) to 3 x 10(-4) M). The relaxation and the contraction were not antagonized by propranolol (up to 3 x 10(-6) M) given 30 min before, suggesting that beta-adrenergic mechanisms were not involved. When 2-PEA was tested on arteries constricted with uridine triphosphate (UTP), similar results were obtained. In the UTP-constricted arteries, the 2-PEA-induced responses were competitively antagonized by 3 x 10(-9) M mepyramine. Together with previous work (Ea Kim et al., 1986), these results are compatible with the hypothesis that H1-receptors were responsible for both the relaxation and the contraction observed. When either indomethacin (10(-8), 3 x 10(-7), or 10(-5) M), dexamethasone (10(-5) M), or tranylcypromine (10(-5) or 10(-4) M) were tested on the response to 2-PEA or 2-methylhistamine, these inhibitors suppressed the relaxation or reversed it to a contraction. Furthermore, they potentiated the contraction induced by these agonists. These results favour the hypothesis that the H1-mediated relaxation in rabbit cerebral arteries may in part involve the release of prostaglandins, especially prostacyclin. The participation of such a prostanoid in histaminergic relaxation seems exclusively an H1-mediated mechanism, since the relaxation induced by the H2-agonist dimaprit (in the presence of mepyramine) was not antagonized by either indomethacin (3 x 10(-7) M) or tranylcypromine (10(-4) M).     

Systemic group B streptococcal disease in neonates and young infants in Norway 1985-94

In the period 1985-94, 237 out of 575 248 (0.41 per 1000) live born infants in Norway were reported to suffer culture-confirmed systemic group B streptococcal disease before their 90th day of life. The annual incidence increased from 0.20 per 1000 live births in 1985 to 0.64 in 1994, due solely to an increase in cases with an onset before the seventh day of life. Future studies should address the possible causes of this increase.     

Aldosterone cord levels in preterm newborn infants

We measured umbilical cord aldosterone concentrations in 64 premature newborn infants. The median serum aldosterone level was 74.5 ngdl^-1 (range 22-280 ng dl^-1). Of the studied perinatal factors, only gestational age and birthweight presented a significant influence on the umbilical cord aldosterone levels. Newborn infants with a gestational age of over 34 weeks and a birthweight of over 2000 g had a significantly higher aldosterone cord level than those aged 34 weeks or younger and 2000 g or less in weight.     

Dummies and the sudden infant death syndrome

The association between dummy use and sudden infant death syndrome (SIDS) was investigated in 485 deaths due to SIDS in the postneonatal age group and compared with 1800 control infants. Parental interviews were completed in 87% of subjects. The prevalence of dummy use in New Zealand is low and varies within New Zealand. Dummy use in the two week period before death was less in cases of SIDS than in the last two weeks for controls (odds ratio (OR) 0.76, 95% confidence interval (CI) 0.57 to 1.02). Use of a dummy in the last sleep for cases of SIDS or in the nominated sleep for controls was significantly less in cases than controls (OR 0.44, 95% CI 0.26 to 0.73). The OR changed very little after controlling for a wide range of potential confounders. It is concluded that dummy use may protect against SIDS, but this observation needs to be repeated before dummies can be recommended for this purpose. If dummy sucking is protective then it is one of several factors that may explain the higher mortality from SIDS in New Zealand than in other countries, and may also explain in part the regional variation within New Zealand.