Elastin point mutations cause an obstructive vascular disease, supravalvular aortic stenosis

Supravalvular aortic stenosis (SVAS) is an inherited obstructive vascular disease that affects the aorta, carotid, coronary and pulmonary arteries. Previous molecular genetic data have led to the hypothesis that SVAS results from mutations in the elastin gene, ELN. In these studies, the disease phenotype was linked to gross DNA rearrangements (35 and 85 kb deletions and a translocation) in three SVAS families. However, gross rearrangements of ELN have not been identified in most cases of autosomal dominant SVAS. To define the spectrum of ELN mutations responsible for this disorder, we refined the genomic structure of human ELN and used this information in mutational analyses. ELN point mutations co-segregate with the disease in four familial cases and are associated with SVAS in three sporadic cases. Two of the mutations are nonsense, one is a single base pair deletion and four are splice site mutations. In one sporadic case, the mutation arose de novo. These data demonstrate that point mutations of ELN cause autosomal dominant SVAS.      

Contextual modulation of synchronization to random dots in the cat visual cortex

Synchronization of neuronal activity has been proposed as a binding mechanism for integration of image properties into one coherent percept. In the present study, we investigated the contextual modulation of synchronization to random dot patterns. Coherent motion of random dots evoked well synchronized responses in area 17 of anaesthetized cats when the stimulus was presented in the compound receptive field of recorded sites. Gradually changing the directional coherence of random dots in the surround while maintaining fully coherent motion of the stimulus in the receptive field significantly suppressed synchronization of neuronal activity for some stimulus conditions. However, usually one or two peaks of increased synchronization were found in the surround coherence tuning curves with low (8–12%) and/or moderate (25–50%) coherence in the surround. At the population level, synchronization was significantly depressed with incoherent motion in the receptive field and when both the surround and the receptive field were jointly stimulated with 0% coherence. The intriguing finding was the discovery of two distinct groups of cells with opposite synchronization changes dependent on the presence or absence of significant synchronization in their spontaneous activity. The latter group of neurons showed peaks of increased synchronization with lower surround coherence, thus probably being more sensitive to the direction of the surround motion. Overall, our findings support the notion that binding of stimulus properties can be achieved by synchronized activity of cortical cells. However, our findings go further than the original hypothesis of feature binding by synchrony to show that synchronization of cortical activity may be directly related to the decision making processes, which in turn are related to the threshold of perception of coherent motion.     

Mutations in Emery-Dreifuss muscular dystrophy and their effects on emerin protein expression

Seventeen families with Emery-Dreifuss muscular dystrophy (EDMD) have been studied both by DNA sequencing and by emerin protein expression. Fourteen had mutations in the X-linked emerin gene, while three showed evidence of autosomal inheritance. Twelve of the 14 emerin mutations caused early termination of translation. An in-frame deletion of six amino acids from the C-terminal transmembrane helix caused almost complete absence of emerin from muscle with no localization to the nuclear membrane, although mRNA levels were normal. This shows that mutant emerin proteins are unstable if they are unable to integrate into a membrane. A 22 bp deletion in the promoter region was expected to result in reduced emerin production, but normal amounts of emerin of normal size were found in leucocytes and lymphoblastoid cell lines. This shows that DNA analysis is necessary to exclude emerin mutations in suspected X-linked EDMD. Emerin levels in female carriers often deviated from the expected 50% and this was due, in at least two families, to skewed emerin mRNA expression from the normal and mutated alleles. In one family with a novel deletion of the last three exons of the emerin gene, a carrier had a cardiomyopathy and very low emerin levels (<5% of normal) due to skewed X-inactivation. In the three autosomal cases of EDMD, emerin was normal on western blots of blood cells, which suggests that autosomal EDMD is not caused by indirect reduction of emerin levels.      

Anxiety during pregnancy and fetal attachment after in-vitro fertilization conception

The aim of this study was to compare 70 couples who had conceived by in- vitro fertilization (IVF) with 63 matched controls for the prevalence of anxiety and quality of attachment to the baby during pregnancy. Results for mothers showed no group differences using a global measure of anxiety, the Spielberger State-Trait Anxiety Inventory. However, pregnancy-specific measures revealed significantly higher levels of anxiety in IVF mothers about the survival and normality of their unborn babies, about damage to their babies during childbirth and about separating from their babies after birth. When IVF mothers were differentiated according to the number of treatment cycles, more differences in anxiety level were revealed, with most increases occurring in mothers who had experienced two or more treatment cycles. IVF fathers did not differ from controls on the global anxiety measure. No data on pregnancy-specific anxiety were available for fathers. Neither IVF mothers nor IVF fathers differed from controls on measures of attachment to the baby during pregnancy. Results are discussed in the context of the need for researchers to employ differentiated and issue-specific measures to identify concerns that may be unique to IVF couples. Clinical implications regarding the need for psychological support during pregnancy are also discussed.      

In vitro immunomodulatory properties of tucaresol in HIV infection

The immunomodulatory properties of tucaresol (compound 589C80) were tested on in vitro antigen- and mitogen-stimulated proliferation and cytokine production by peripheral blood mononuclear cells (PBMC) of HIV-infected individuals and healthy controls (HC). Results showed that tucaresol: (1) increases influenza A virus-, gp 160 peptide-, and HLA alloantigen-stimulated proliferation as well as interleukin (IL)-2 and interferon gamma (IFN gamma) production by PBMC of HIV-infected individuals with higher CD4 counts (>500/microl) but had only a marginal immunomodulatory effect on PBMC of patients with lower CD4 counts (<500/microl); (2) did not modify IL-10 production; (3) augmented CD25 expression on mitogen-stimulated T cells of HC but not of HIV-infected individuals; and (4) marginally increased CTL activity. The immunomodulatory properties of tucaresol were confirmed by PCR analyses; additional data showed that tucaresol costimulated CD3-dependent triggering of T cells and that this stimulation was independent of CD28 costimulation. The immunomodulatory effects of tucaresol on T cell functions are characterized by a bell-shaped dose response curve; the action of the compound is optimal in the 100 to 300 microM range. Analyses of mitogen-stimulated apoptosis demonstrated that the lack of effect of tucaresol at higher doses is not the result of increased cell death, suggesting a role of functional impairment. These data confirm that tucaresol can stimulate T helper cell function and enhance the production of type 1 cytokines, thus eliciting cell-mediated immunity, and warrant its potential utility in the therapy of HIV infection.     

Occurrence and Potential Diagnostic Applications of Serological Cross-Reactivities between Brucella and Other Alpha-Proteobacteria

Agrobacterium, Sinorhizobium, and Ochrobactrum are genera closely related to Brucella but, in contrast to the latter, are not pathogenic for humans and animals. We studied by an indirect enzyme-linked immunosorbent assay (ELISA) the reactivities of brucellosis sera against cytosolic (CYT) and membrane (MA) antigens from these nonpathogenic bacteria, and we evaluated the potential usefulness of these cross-reactions for the diagnosis of brucellosis in humans, sheep, cows, and dogs. Canine infection by Brucella canis was detected with high specificity by CYT antigen-based ELISAs (96% for Agrobacterium, 96% for Sinorhizobium, and 91% for Ochrobactrum), while sensitivity was variable (58% for Agrobacterium, 88% for Sinorhizobium, and 84% for Ochrobactrum). In addition, it was possible to diagnose canine disease shortly after exposure to the pathogen (15 days). Similar results for canine brucellosis were obtained with MA antigens. In contrast, normal sera from humans, sheep, and cattle reacted strongly with all the antigens (CYT and MA antigens from the three bacteria), producing high cutoff values and, consequently, low sensitivities. While for some host species the reactivity patterns of normal sera by Western blotting were similar to those produced with sera from infected individuals, the reactivity pattern of bovine sera against Sinorhizobium meliloti antigens exhibited some differential bands for the two groups of sera. These results show that crude fractions from nonpathogenic alpha-proteobacteria can be used to diagnose canine brucellosis but may need to be further separated into simpler fractions to have diagnostic usefulness in ovine, bovine, or human infection. By reducing the biosafety requirements, the use of antigens derived from these nonpathogenic bacteria would simplify the production of diagnostic kits for brucellosis, especially in settings where biosafety level-3 facilities are scarce or absent.     

Microglia are more susceptible than macrophages to apoptosis in the central nervous system in experimental autoimmune encephalomyelitis through a mechanism not involving Fas (CD95)

Morphological studies have shown that macrophages and microglia undergo apoptosis in the central nervous system (CNS) in acute experimental autoimmune encephalomyelitis (EAE) in the Lewis rat. To assess the relative levels of macrophage and microglial apoptosis, and the molecular mechanisms involved in this process, we used three-colour flow cytometry to identify CD45lowCD11b/c+ microglial cells and CD45highCD11b/c+ macrophages in the inflammatory cells isolated from the spinal cords of Lewis rats 13 days after immunization with myelin basic protein (MBP) and complete Freund's adjuvant. Simultaneously, we analyzed the DNA content of these cell populations to assess the proportions of cells undergoing apoptosis and in different stages of the cell cycle or examined their expression of three apoptosis- regulating proteins, i.e. Fas (CD95), Fas ligand (FasL) and Bcl-2. Microglia were highly vulnerable to apoptosis and were over-represented in the apoptotic population. Macrophages were less susceptible to apoptosis than microglia and underwent mitosis more frequently than microglia. The different susceptibilities of microglia and macrophages to apoptosis did not appear to be due to variations in Fas, FasL or Bcl- 2 expression, as the proportions of microglia and macrophages expressing these proteins were similar, and were relatively high. Furthermore, in contrast to T cell apoptosis, apoptosis of microglia/macrophages did not occur more frequently in cells expressing Fas or FasL, or less frequently in cells expressing Bcl-2. These results indicate that the apoptosis of microglia and CNS macrophages in EAE is not mediated through the Fas pathway, and that Bcl-2 expression does not protect them from apoptosis. Expression of FasL by macrophages and microglia may contribute to the pathogenesis and immunoregulation of EAE through interactions with Fas+ oligodendrocytes and Fas+ T cells. The high level of microglial apoptosis in EAE indicates that microglial apoptosis may be an important homeostatic mechanism for controlling the number of microglia in the CNS following microglial activation and proliferation.