Coupling between neuronal nitric oxide synthase and glutamate receptor 6-mediated c-Jun N-terminal kinase signaling pathway via S-nitrosylation contributes to ischemia neuronal death

S-nitrosylation, as a post-translational protein modification, recently has been paid more and more attention in stroke research. S-nitrosylation regulates protein function by the mechanisms of covalent attachment that control the addition or the removal of nitric oxide (NO) from a cysteine thiol. The derivation of NO is established by the demonstration that, in cerebral neurons, NO mainly generates from neuronal nitric oxide synthase (nNOS) during the early stages of reperfusion. In the past researches, we demonstrate that global ischemia-reperfusion facilitates the activation of glutamate receptor 6 (GluR6) -mediated c-Jun N-terminal kinase (JNK) signaling pathway. The objective of this study is primarily to determine, during the early stages of reperfusion in rat four-vessel occlusion (4-VO) ischemic model, whether nNOS-derived NO affects the GluR6-mediated JNK signaling route via S-nitrosylation which is performed mainly by the biotin switch assay. Here, we show that administration of 7-nitroindazole, an inhibitor of nNOS, or ketamine, an antagonist of N-methyl-d-aspartate receptor (NMDAR), diminishes the increased S-nitrosylation of GluR6 induced by cerebral ischemia-reperfusion. In contrast, 2-amion-5,6-dihydro-6-methyl-4H-1,3-thiazine, an inhibitor of inducible NO synthase does not affect S-nitrosylation of GluR6. Moreover, treatment with sodium nitroprusside (SNP), an exogenous NO donor, increases the S-nitrosylation and phosphorylation of nNOS, leading to the attenuation of the increased S-nitrosylation of GluR6 and the assembling of GluR6* postsynaptic density protein 95 (PSD95)* mixed lineage kinase 3 (MLK3) signaling module induced by cerebral ischemia-reperfusion. The results also show that GluR6 downstream MLK3* mitogen activated protein kinase kinase 4/7* JNK signaling module and nuclear or non-nuclear apoptosis pathways are involved in the above signaling route. However, dithiothreitol (DTT) antagonizes the neuroprotection of SNP. Treatment with DTT alone, as a negative control, prevents S-nitrosylation of proteins, which indicates the existence of endogenously produced S-nitrosylation. These data suggest that GluR6 is S-nitrosylated by endogenous NO in cerebral ischemia-reperfusion, which is possibly correlated with NMDAR* PSD95* nNOS signaling module, and further activates GluR6* PSD95* MLK3 signaling module and JNK signaling pathway. In contrast, exogenous NO donor antagonizes the above action of endogenous NO generated from nNOS. Thus, our results provide the coupling of nNOS with GluR6 by S-nitrosylation during the early stages of ischemia-reperfusion, which can be a new approach for stroke therapy.

Biomechanical effects of autonomous augmentation on the adjacent unaugmented vertebral bodies: influence of the number of functional spinal units in a finite element model

PURPOSE

The results of finite element analysis (FEA) studies on the effect of augmentation of one vertebral body (VB), using vertebroplasty (VP) or balloon kyphoplasty (BKP), on the biomechanics of the adjacent and nonadjacent VBs are contradictory. One reason for this record is that different levels of the spine, numbers of structures, and numbers of functional spinal units (FSUs) (X) were included in the models used in different studies. The purpose of the present study was to clarify this effect as far as X is concerned.

METHODS

A validated three-dimensional solid model of the lumbar spine was constructed from computed tomography scans and prophylactic augmentation of L2 was simulated. In the FEA, the model was subjected to a uniformly distributed compressive load (total load = 1300 N) on the superior endplate of L1. The extent to which a change in X affects the values of the mean von Mises stress (sigmaVM) and the mean elastic strain energy density (ESED) in all structures adjacent to L2 was determined. (These changes were with respect to the case where all the VBs in the model are intact.)

RESULTS

As X increased (from 1 to 2, from 2 to 3, and from 3 to 4), there were clear variations in the number of stable changes in both sigmaVM and ESED in each structure. The largest number of these changes occurred when X changed from 2 to 3.

CONCLUSION

The results suggest that three is the number of FSUs that should be included in models of the lumbar spine to be used in FEA studies of VP and BKP.

Molecular epidemiology of Pseudomonas aeruginosa in adult patients with cystic fibrosis in Northern Ireland

Isolates (n = 51) of Pseudomonas aeruginosa obtained from the sputa of 29 adult patients attending the Regional Cystic Fibrosis Centre in Northern Ireland were compared using an enterobacterial repetitive intergenic consensus sequence (ERIC2) primer in a random amplification of polymorphic DNA (RAPD) polymerase chain reaction (PCR) method. Resulting banding patterns showed a high degree of genetic heterogeneity among all isolates from the patients examined, suggesting a non-clonal relationship between isolates from these patients, when employing this genotyping technique.

Genetic susceptibility and haplotype analysis between Fcγ receptor IIB and IIIA gene with systemic lupus erythematosus in Chinese population

The objective of this study is to understand the role of FcγRIIB and FcγRIIIA gene in susceptibility to systemic lupus erythematosus (SLE), and to examine possible susceptible haplotypes between two genes. A total of 119 patients with SLE from 95 nuclear families, aged from 14 to 78 years, were selected according to 1997 criteria of American College of Rheumatology. In addition, 316 family members of these patients were also genotyped. A family-based association study was used to explore the relationship between gene polymorphism and SLE. We studied 13 single-nucleotide polymorphisms (SNPs) encoding non-synonymous substitution in the FcγRIIB and FcγRIIIA gene (four SNPs in the FcγRIIB gene and nine SNPs in the FcγRIIIA gene) with respect to genetic susceptibility to SLE. All SNPs were genotyped by restriction fragment length polymorphism method. Among 13 SNPs, univariate (single-marker) family-based association tests showed that variant alleles at only four SNPs (rs10917661 and rs1050501, in exon 2 and exon 5 of FcγRIIB gene, rs403016 and rs428888, in exon3 of FcγRIIIA gene respectively) were significantly associated with genetic susceptibility to SLE. Furthermore, the haplotype-specific FBATs showed 50Ter-225Thr (34.1%, in FcγRIIB gene) and 72Arg-118Asn (40%, in the FcγRIIIA gene) haplotype were more frequently transmitted in SLE than other haplotypes ( Z = 3.539, P = 0.00042; Z = 2.678, P = 0.007412 respectively). But haplotypes were not found between FcγRIIB and FcγRIIIA gene Our results suggest that there were meaningful haplotype in FcγRIIIA and FcγRIIB gene respectively. FcγRIIIA and FcγRIIB genes in the pathogenesis of SLE may play an independent role in Chinese population.

Emergence and reproductive rhythms of Ephestia kuehniella (Lepidoptera Pyralidae)

Mediterranean flour moth Ephestia kuehniella is a cosmopolitan pest of stored products and its eggs are widely used to rear parasitoids and predators for biological control programmes The laboratory investigations of circadian rhythms and lifespan patterns described in this paper have shown that females had significantly shorter developmental duration from egg to adult than males Emergence occurred throughout the 24 h cycle in both sexes with a peak at dusk Mating mainly occurred during scotophase and peaked on the emergence day while oviposition peaked 1 day after emergence Calling courtship and mating peaked in the second half of scotophase and oviposition peaked at the start of scotophase Permanently paired insects mated up to 3 times with an average of 2 013 matings Dissection of dead females showed the number of spermatophores in the bursa copulatrix equalled the number of observed matings

European earwig as a potential biological control agent of apple leafcurling midge

The European earwig Forficula auricularia L is an important predator of aphids and scales in New Zealand apple orchards To determine whether European earwig acted as a biological control agent of apple leafcurling midge (ALCM) Dasineura mali Kieffer their prey searching and feeding activity was investigated in the field and laboratory In the field in January earwigs started to leave their shelters at about 920 pm to search for ALCM larvae and returned to the shelters before 535 am with a searching peak on apple shoots infested by ALCM larvae between 1030 pm and 130 am Significantly more ALCM infested shoots and leaves were bitten by earwigs on trees where shelters trapped earwigs than on those where shelters did not trap any earwigs In the laboratory earwigs mainly fed in the first 2 hours after lightoff and each adult consumed an average of 6770 318 mature ALCM larvae during the scotophase (8 h) Heavier earwigs consumed significantly more ALCM larvae than light ones

Prevalence of gastrointestinal bacterial pathogens in a population of zoo animals

Faecal prevalence of gastrointestinal bacterial pathogens, including Campylobacter, Escherichia coli O157:H7, Salmonella, Shigella, Yersinia, as well as Arcobacter, were examined in 317 faecal specimens from 44 animal species in Belfast Zoological Gardens, during July-September 2006. Thermophilic campylobacters including Campylobacter jejuni, Campylobacter coli and Campylobacter lari, were the most frequently isolated pathogens, where members of this genus were isolated from 11 animal species (11 of 44; 25%). Yersinia spp. were isolated from seven animal species (seven of 44; 15.9%) and included, Yersinia enterocolitica (five of seven isolates; 71.4%) and one isolate each of Yersinia frederiksenii and Yersinia kristensenii. Only one isolate of Salmonella was obtained throughout the entire study, which was an isolate of Salmonella dublin (O 1,9,12: H g, p), originating from tiger faeces after enrichment. None of the animal species found in public contact areas of the zoo were positive for any gastrointestinal bacterial pathogens. Also, water from the lake in the centre of the grounds, was examined for the same bacterial pathogens and was found to contain C. jejuni. This study is the first report on the isolation of a number of important bacterial pathogens from a variety of novel host species, C. jejuni from the red kangaroo (Macropus rufus), C. lari from a maned wolf (Chrysocyon brachyurus), Y. kristensenii from a vicugna (Vicugna vicugna) and Y. enterocolitica from a maned wolf and red panda (Ailurus fulgens). In conclusion, this study demonstrated that the faeces of animals in public contact areas of the zoo were not positive for the bacterial gastrointestinal pathogens examined. This is reassuring for the public health of visitors, particularly children, who enjoy this educational and recreational resource.

Prior SO2 exposure promotes airway inflammation and subepithelial fibrosis following repeated ovalbumin challenge

BACKGROUND

Exposure to allergens or air pollutants often leads to asthma exacerbations associated with aggravation of airway inflammation. Although, repeated allergen challenge often induces chronic allergic airway inflammation (CAAI) and airway remodelling, yet, the effects of brief exposure to air pollutants such as SO(2) on development of CAAI and airway remodelling remain to be clarified.

OBJECTIVE

The aim of the experiment was to investigate the effects of acute neutrophilic airway inflammation induced by brief exposure to SO(2) on development of CAAI and subepithelial fibrosis (SEF) in a murine model of asthma.

METHODS

Acute airway inflammation was induced by brief exposure to 50 p.p.m. SO(2) (1 h/d, 3 days). CAAI and SEF in BALB/c mice were induced by repeated challenge with ovalbumin (OVA) for 5 or 9 weeks with or without prior exposure to SO(2). Bronchoalveolar lavage fluid (BALF) eosinophilia as index of CAAI, BALF endothelin-1 (ET-1) and TGF-beta1 levels, morphometric evaluation of fibrotic area beneath subbasement membrane and lung hydroxyproline content (Hyp) as indexes of SEF were monitored.

RESULTS

Exposure to SO(2) led to acute neutrophilic inflammation and epithelial sloughing with profound elevation of BALF ET-1. Repeated OVA challenge resulted in CAAI and SEF along with elevation of Hyp, increase of fibrotic area beneath subbasement membrane and elevation of BALF TGF-beta1. Preceding SO(2) exposure exaggerated BALF eosinophilia, facilitated and enhanced SEF with more significant elevation of BALF ET-1 and TGF-beta1 levels compared with OVA-challenged mice without prior exposure to SO(2). The increase of Hyp was positively correlated with elevation of BALF TGF-beta1 during CAAI (r=0.842, P<0.01).

CONCLUSION

This data demonstrated that SEF developed in parallel with severity and time course of CAAI following repeated OVA challenge. SO(2)-induced acute epithelial injury and neutrophilic inflammation could enhance CAAI and promote SEF, probably through overexpression of ET-1 and TGF-beta1.

The profile of gene expression and role of nuclear factor kappa B on glomerular injury in rats with Thy-1 nephritis

Mesangioproliferative glomerulonephritis (MsPGN) is a disease of high incidence in humans. Rats with Thy-1 nephritis (Thy-1 N) are used as an animal model for studying MsPGN. Although several studies have demonstrated that many pathological factors could cause the injury of glomerular mesangial cells (GMCs) in Thy-1 N, changes of profile and the molecular mechanism of the disease (i.e. the role of transcription factors) at intervals remain unclear. The purpose of this study was to identify the changes in gene expression profile and to observe the role of nuclear factor kappa B (NF-kappaB) on the pathological change of renal tissue in Thy-1 N rats. Our results showed that the pathological changes of GMCs in Thy-1 N included three phases: apoptosis (40 min), necrosis (24 h) and proliferation (7 days). Concomitantly, at 40 min and on day 7, the up-regulation of 341 genes and 250 genes were observed, while 392 genes and 119 genes were down-regulated in Thy-1 N. Expression of interleukin (IL)-1beta, IL-6, proliferating cell nuclear antigen, alpha-smooth muscle actin, collagen type IV and excretion of urinary protein was increased in rats with Thy-1 N and decreased in pyrrolidine dithiocarbamate-treated rats with Thy-1 N. These data indicated that the significant changes in the gene profile were coupled with the pathological changes of Thy-1 N, and activation of NF-kappaB may contribute to the pathogenesis of GMCs apoptosis, proliferation, extracelluar matrix accumulation and proteinuria in Thy-1 N.