Amino acid substitutions within the heptad repeat domain 1 of murine coronavirus spike protein restrict viral antigen spread in the central nervous system

Targeted recombination was carried out to select mouse hepatitis viruses (MHVs) in a defined genetic background, containing an MHV-JHM spike gene encoding either three heptad repeat 1 (HR1) substitutions (Q1067H, Q1094H, and L1114R) or L1114R alone. The recombinant virus, which expresses spike with the three substitutions, was nonfusogenic at neutral pH. Its replication was significantly inhibited by lysosomotropic agents, and it was highly neuroattenuated in vivo. In contrast, the recombinant expressing spike with L1114R alone mediated cell-to-cell fusion at neutral pH and replicated efficiently despite the presence of lysosomotropic agents; however, it still caused only subclinical morbidity and no mortality in animals. Thus, both recombinant viruses were highly attenuated and expressed viral antigen which was restricted to the olfactory bulbs and was markedly absent from other regions of the brains at 5 days postinfection. These data demonstrate that amino acid substitutions, in particular L1114R, within HR1 of the JHM spike reduced the ability of MHV to spread in the central nervous system. Furthermore, the requirements for low pH for fusion and viral entry are not prerequisites for the highly attenuated phenotype.     

Genetic linkage analysis identifies new proximal and distal flanking markers for the X-linked agammaglobulinemia gene locus, refining its localization in Xq22

Genetic linkage analysis has been instrumental in mapping thegene for X-linked agammaglobulinemia (XLA) to the proximal longarm of the human X chromosome, to Xq22. Due to the relativerarity of this disease the localization of the gene within Xq22has remained imprecise. We have investigated twenty-nine familiesaffected by XLA and have found no recombinants with the DXS178locus in over 30 informative meioses. DXS178 is now the mostreliable and informative locus for use in pre-natal diagnosisand carrier detection of XLA. In addition, we have identifiednew closely linked proximal and distal flanking markers forXLA, DXS442 and DXS101, respectively. These loci are separatedby 2cM, considerably reducing the extent of DNA within whichthe XLA locus can be contained. This will open up the way formore directed positional cloning efforts for the isolation ofthe XLA gene.     

Psychophysiological correlates of induced headaches

The psychophysiological correlates of induced headaches were examined. Subjects with frequent muscle-contraction headaches, frequent migraine headaches, or infrequent headaches were exposed to a 1-h cognitive stressor while multiple electromyographic and cardiovascular measures were monitored. The stressor was associated with significant changes in all psychophysiological measures. Eleven of 16 headache subjects and 2 of 8 control subjects developed headaches. Significant associations between several psychophysiological variables and headache occurrence were found and individual differences in the association between psychophysiological variables and headaches intensity were examined. The results were consistent with the hypothesized role of cardiovascular factors in the pathophysiology of muscle-contraction headache. This was the first controlled demonstration of headaches occurring as a function of environmental stressors.This research was supported by Grant 5-R01-NS-1875 from the National Institute of Health.     

Psychometric Properties of Resting Anterior EEG Asymmetry: Temporal Stability and Internal Consistency

We examined whether resting anterior electroencephalographic (EEG) asymmetry in the alpha frequency band has psychometric properties that would be expected of a measure assessing individual differences. In each of two experimental sessions, separated by three weeks, resting EEG in midfrontal and anterior temporal sites was recorded from 85 female adults during eight 60-s baselines. Resting alpha asymmetry demonstrated acceptable test-retest stability and excellent internal consistency reliability. Analyses including other frequency bands indicated that degree of stability varied somewhat as a function of band and region. In addition, asymmetry was less stable than absolute power. Discussion focuses on the implications of the present findings for the measurement and conceptualization of resting anterior asymmetry.     

Identification, characterization and biological activity of oxytocin receptor in the developing human penis

Although abnormalities of the male external genitalia (MEG) are a relatively common problem, little is known concerning the molecular mechanisms that finely regulate penile development. We report here the expression of the oxytocin receptor (OTR) gene by real-time RT-PCR in human fetal tissues (11th-12th week of gestation), including the MEG. The developing penis expressed a very high level of OTR mRNA, only a half log(10) unit lower than fetal central nervous system, used as a positive control. The OTR protein is also highly expressed (western, immunohistochemistry and binding studies) and immunolocalized both in the mesenchymal body and in the surrounding blood capillaries, which will later constitute penile trabeculae and sinusoids. Binding studies using [125I]oxytocin antagonist ([125I]OTA) in cultured human fetal penile smooth muscle cells (hfPSMC) revealed the presence of specific OTR with a high capacity and affinity for oxytocin (OT) and for OTA. Increasing concentrations of OT dose-dependently induced intracellular Ca2+ mobilization. Furthermore, OTR mediated an increase in the proliferation and the migration of hfPSMC. In conclusion, we demonstrate that in the developing human MEG, OTR is highly expressed and might be involved in coordinating timely and appropriate proliferation and migration of the penile cells. Thus, OTR might represent an additional target for investigating human fetal MEG organogenesis.     

Alternate Pathway Activation in Sickle Cell Disease and ��-Thalassemia Major

Total hemolytic complement activity (CH50), immuno-electrophoretic conversion of Factor B (C3PA), and of C3 were studied in 16 patients with sickle cell disease in a steady state, eight patients in crisis, and ten patients with β-thalassemia major anemia maintained on a constant transfusion regimen. Patients with sickle cell disease in a steady state have moderatley 56 (percent) depressed conversion of Factor B in addition to markedly decreased conversion of C3 in four of ten patients. One of the three sickle cell patients and two of the four thalassemia patients with low C3 conversion levels have died subsequent to the studies. The combination of chronically decreased Factor B conversion in the face of markedly decreased C3 conversion may make these patients occasionally vulnerable to overwhelming infection analagous to the situation seen in postsplenectomy cases.