Nicotinic receptor alpha7-subunits are coupled to the stimulation of nitric oxide synthase in rat dorsal root ganglion neurons

In dorsal root ganglia (DRG) intraganglionic communication takes place both among neurons and between neurons and satellite cells. One diffusible substance involved in this signalling is nitric oxide (NO), and acetylcholine (ACh) is a candidate for the stimulation of intraganglionic NO synthesis. DRG neurons react to ACh-receptor stimulation with NO-dependent cGMP production. Here, we investigated the role of the 7-subunit containing Ca²⁺-permeable nicotinic ACh receptors (nAChR) in this process. The 7-nAChR mRNA and the protein were expressed in virtually all lumbar DRG neurons as evidenced by laser-assisted cell picking and oligo cell RT-PCR, in situ hybridisation and immunohistochemistry. Strong 7-nAChR immunoreactivity was present in vanilloid receptor 1-immunoreactive, i.e. nociceptive, neurons. A neuronal production of NO in response to nicotine could be demonstrated in DRG slice preparations utilising the NO-sensitive fluorescent indicator diaminofluorescein diacetate (DAF-2DA). This stimulation of NO production was sensitive to inhibition of 7-nAChR by mecamylamine and -bungarotoxin, to inhibition of nitric oxide synthase (NOS) with L-NAME and L-NMMA, and to the blockade of voltage-operated Ca²⁺ channels by verapamil. The results show the presence of the 7-nAChR subunit in nociceptive rat DRG neurons and provide evidence for its coupling to NOS activation, indicating a role of this pathway in the intraganglionic communication in sensory ganglia.     

Geographic dynamics of viral encephalitis in Thailand

Viral encephalitis (VE) continues to be a major disease in Asia, causing serious illness which may result in death or have neurological sequelae. This study involves an ecological analysis of the climatic, geographic and seasonal patterns of clinically reported VE in Thailand from 1993 to 1998 to investigate regional and seasonal differences in disease incidence. Three thousand eight hundred and twenty nine cases of VE were clinically diagnosed nationwide during the study period by the Thai Ministry of Public Health. Spearman rank correlations of temporal, spatial and geographic variables with disease incidence were performed. The monthly incidence of VE correlated significantly with seasonal changes in temperature, relative humidity and rainfall in the north-northeast region of Thailand (P < 0.001), whereas incidence in the south-central region correlated only with relative humidity (P = 0.003). Spatial analysis revealed a positive correlation of disease with elevation (P < 0.001), and negative correlations with rice-field cover (P < 0.001), agricultural land-use (P < 0.001) and temperature (P = 0.004) in the north-northeast region. No significant spatial correlation was identified in the south-central region. The spatial distribution of VE suggests that etiologic variations may be responsible, in part, for the geographic patterns of disease. Active etiologic surveillance is necessary in a variety of geographic settings in order to provide physicians with information necessary for disease prevention and clinical management.     

Lymphocyte propionyl-CoA carboxylase and accumulation of odd-chain fatty acid in plasma and erythrocytes are useful indicators of marginal biotin deficiency small star,filled

BACKGROUND: Recent studies indicate marginal biotin deficiency is more common than previously thought. That conclusion's validity rests on two indicators of biotin status that depend on renal function.OBJECTIVE: Assessing the validity of two indicators of biotin status that do not depend upon renal function: 1) activity of the biotin-dependent enzyme propionyl-CoA carboxylase (PCC) in lymphocytes and 2) accumulation of odd-chain fatty acids in the lipids of plasma and erythrocytes.DESIGN: Marginal biotin deficiency was induced in 11 healthy adults by egg-white feeding for 28 days. Blood and 24-h urine samples were collected before commencing the diet and twice weekly thereafter. After depletion, biotin status was restored with a general diet with or without 80 &mgr;g/day or 328 nmol/day biotin supplement. Activity of PCC was determined by an optimized NaH 14CO(3) incorporation assay. Fatty acid composition was determined by gas chromatography.RESULTS: With time on the egg-white diet, lymphocyte PCC activity decreased significantly (P <0.0001); C15:0 and C17:0 content increased significantly in the lipids of plasma and erythrocytes (P <0.015). In eight of 11 subjects, lymphocyte PCC activity returned to normal within three weeks of resuming general diets with or without biotin supplement. With repletion, C15:0 and C17:0 in plasma lipids decreased (P <0.02), but odd-chain content of erythrocytes did not decrease significantly.CONCLUSIONS: Lymphocyte PCC activity is an early and sensitive indicator of marginal biotin deficiency. Odd-chain fatty acids accumulate in blood lipids more gradually during marginal deficiency and return to normal more gradually after biotin repletion.     

Expression of Lex antigen in Schistosoma japonicum and S.haematobium and immune responses to Lex in infected animals: lack of Lex expression in other trematodes and nematodes

Adults of the human parasitic trematode Schistosoma mansoni, which causes hepatosplenic/intestinal complications in humans, synthesize glycoconjugates containing the Lewis x (Lex) Galbeta1-->4(Fucalpha1-- >3)GlcNAcbeta1-->R, but not sialyl Lewis x (sLex), antigen. We now report on our analyses of Lexand sLexexpression in S.haematobium and S.japonicum, which are two other major species of human schistosomes that cause disease, and the possible autoimmunity to these antigens in infected individuals. Antigen expression was evaluated by both ELISA and Western blot analyses of detergent extracts of parasites using monoclonal antibodies. Several high molecular weight glycoproteins in both S. haematobium and S. japonicum contain the Lexantigen, but no sialyl Lexantigen was detected. In addition, sera from humans and rodents infected with S.haematobium and S.japonicum contain antibodies reactive with Lex. These results led us to investigate whether Lexantigens are expressed in other helminths, including the parasitic trematode Fasciola hepatica , the parasitic nematode Dirofilaria immitis (dog heartworm), the ruminant nematode Haemonchus contortus , and the free-living nematode Caenorhabditis elegans . Neither Lexnor sialyl-Lexis detectable in these other helminths. Furthermore, none of the helminths, including schistosomes, express Lea, Leb, Ley, or the H- type 1 antigen. However, several glycoproteins from all helminths analyzed are bound by Lotus tetragonolobus agglutinin , which binds Fucalpha1-->3GlcNAc, and Wisteria floribunda agglutinin, which binds GalNAcbeta1-->4GlcNAc (lacdiNAc or LDN). Thus, schistosomes may be unique among helminths in expressing the Lexantigen, whereas many different helminths may express alpha1,3-fucosylated glycans and the LDN motif.      

Looking Upstream: Findings from Focus Groups on Public Perceptions of Source Water Quality in British Columbia,Canada

In association with the development of new microbial tests for source water quality (SWQ), focus groups with members of the public were conducted to gain insight into their perceptions of SWQ, behaviours and contaminants they think pose the greatest threat to its quality, and what/how they want to know about SWQ. Discussions revealed a low concern about SWQ in general, and in particular about microbial contamination. Participants identified behaviours that threaten SWQ, barriers to changing behaviour and suggestions for inducing change. A strong desire was expressed for water quality information to be interpreted and communicated in terms of how SWQ may impact human health and how their actions should be altered in response to test results. The information can be used to inform communication strategies and possibly impact policies associated with water quality testing and implementation of new tests. More broadly, awareness of the public’s understanding and beliefs about source water can be used in working with the public to adopt water-friendly behaviours, influence the content and methods of communicating with the public about water issues and water quality, and could contribute to the direction of future research and investment into water technologies to align with the public’s priorities.     

Cell-autonomous roles of the ecdysoneless gene in Drosophila development and oogenesis

Steroid signaling underlies developmental processes in animals. Mutations that impair steroidogenesis in the fruit fly Drosophila melanogaster provide tools to dissect steroid hormone action genetically. The widely used temperature-sensitive mutation ecdysoneless(1) (ecd(1)) disrupts production of the steroid hormone ecdysone, and causes developmental and reproductive defects. These defects cannot be satisfactorily interpreted without analysis of the ecd gene. Here, we show that ecd encodes an as yet functionally undescribed protein that is conserved throughout eukaryotes. The ecd(1) conditional allele contains an amino acid substitution, whereas three non-conditional larval lethal mutations result in truncated Ecd proteins. Consistent with its role in steroid synthesis, Ecd is expressed in the ecdysone-producing larval ring gland. However, development of ecd-null early larval lethal mutants cannot be advanced by Ecd expression targeted to the ring gland or by hormone feeding. Cell-autonomous ecd function, suggested by these experiments, is evidenced by the inability of ecd(-) clones to survive within developing imaginal discs. Ecd is also expressed in the ovary, and is required in both the follicle cells and the germline for oocyte development. These defects, induced by the loss of ecd, provide the first direct evidence for a cell-autonomous function of this evolutionarily conserved protein.     

MEPD: a resource for medaka gene expression patterns

The Medaka Expression Pattern Database (MEPD) is a database for gene expression patterns determined by in situ hybridization in the small freshwater fish medaka (Oryzias latipes). Data have been collected from various research groups and MEPD is developing into a central expression pattern depository within the medaka community. Gene expression patterns are described by images and terms of a detailed medaka anatomy ontology of over 4000 terms, which we have developed for this purpose and submitted to Open Biological Ontologies. Sequences have been annotated via BLAST match results and using Gene Ontology terms. These new features will facilitate data analyses using bioinformatics approaches and allow cross-species comparisons of gene expression patterns. Presently, MEPD has 19,757 entries, for 1024 of them the expression pattern has been determined.     

Forelimb muscle activity following nerve graft repair of ventral roots in the rat cervical spinal cord

Current research on the cellular mechanisms of nerve regeneration suggests the application of nerve growth factors at the repair sites to be beneficial. To test the effectiveness of this approach, we performed transections of the C6 and C7 ventral rootlets from their original sites in the spinal cord of 18 rats. We investigated the electrophysiological changes in three groups of rats operated on by different repair strategies. Six rats comprised the control group (G1). In the other 12 rats, 24 rootlets were implanted into the spinal cord by means of an intercostal nerve graft through the pia mater immediately after transection. Six rats (G2) had fibrin glue applied at the incision. The last 6 rats (G3) had grafts with acidic fibroblast growth factor (aFGF) added to the fibrin glue. The rats' functional recovery was evaluated electrophysiologically at 6 weeks and 6 months after the operation. Needle electromyography showed profound fibrillation potentials (Daube's scoring system) in the deltoid, biceps, and triceps of the operated forelimbs in all groups 6 weeks after the operation. After 6 months, there was a significant decrease in the amount of fibrillation potentials in all groups (G1, G2 and G3, p < 0.0001, 0.0001, 0.0009, respectively, generalized estimating equation, repeated measures) and a significantly high probability for motor units present in sampled muscles of G2 and G3 as compared to G1 (log odds ratio in G2 = 51.8316, G3 = 57.4262, generalized estimating equation). We conclude that several cervical roots can regenerate through intercostal nerve grafts applied using fibrin glue. Adding aFGF may increase the efficacy of sprouting.