Radioimmunological study of the hemagglutinin of influenza viruses subtype H1N1

Radioimmunoassay were carried out with influenza A/Cambridge/46, A/FM/1/47, A/England/1/51, A/Denwer/1/57, and A/USSR/90/79 of the H1N1 subtype to determine the antigenic determinants of influenza A/USSR/90/77 virus hemagglutinin. The test system included 125I-labeled hemagglutinin of A/USSR/90/77 virus and homologous antiserum to this virus. The most marked antigenic similarity was found between A/USSR/90/77 and A/USSR/90/79 viruses. The A/Cambridge/46 and A/Denwer/1/57 viruses showed clear-cut differences in the antigenic determinants from the A/USSR/90/77 virus.     

Detection and characterization of new influenza B virus variants in 2002

One-hundred five influenza B-positive specimens obtained from southeast Asia in 2002 were categorized on the basis of DNA sequencing of HA1 gene as well as real-time PCR analysis of the NA gene. Phylogenetic analysis of the HA1 gene sequences showed that the majority of the viruses (96.2%) belonged to the B/Victoria/2/87 lineage, while a smaller percentage of the viruses (3.8%) belonged to the B/Yamagata/16/88 lineage. The B/Yamagata/16/88 viruses displayed significant antigenic drift in the deduced amino acid sequences of the HA1 protein, and the B/Victoria/2/87-like viruses consisted of B/Hong Kong/1351/02-like (72.3%) and B/Hong Kong/330/01-like (27.7%) viruses. The B/Hong Kong/1351/02-like viruses were reassortants with the HA gene belonging to the B/Victoria/2/87 lineage and the NA gene belonging to the B/Yamagata/16/88 lineage, whereas both the HA and NA genes of B/Hong Kong/330/01 virus belonged to the B/Victoria/2/87 lineage. In this study, however, all the B/Hong Kong/330/01-like isolates exhibited the B/Yamagata/16/88-like NA gene, which likely resulted from reassortment of B/Hong Kong/330/01 and B/Hong Kong/1351/02 viruses during coinfection. Additional molecular characterization of the six internal genes showed that the M, NS, PA, and PB2 genes of the new variants were B/Hong Kong/1351/02 in origin, whereas the NP and PA genes retained the B/Hong Kong/330/01 origin. Interestingly, these new variants all appeared late in the year 2002. These results support the notion that influenza B viruses continued to evolve through antigenic drift and shift.     

The growth of attenuated influenza vaccine donor strains in continuous cell lines

The growth of the Russian live attenuated influenza vaccine donor strains A/Leningrad/134/17/57, A/Leningrad/134/47/57 and B/USSR/60/69 was studied in cells of the VERO and Madin-Darby canine kidney (MDCK) lines as six-well cultures and cell factories infected at different multiplicities of infection. Yields for A/Leningrad/134/17/57 and A/Leningrad/134/47/57 were comparable in either cell line over a range of multiplicities but were about 10-fold lower than in the allantoic fluids of infected chicken embryos. For both A/Leningrad/134/47/57 and B/USSR/60/69, yields from the MDCK line were about 10-fold higher than for the VERO line. For B/USSR/60/69, yields in eggs were approximately 100-fold higher than those obtained in the MDCK line. A feature of the growth of B/USSR/60/69 was its reduced capacity to produce infectious progeny in either cell line at multiplicities of infection of 2.0 or 1.0 pfu/cell. Inhibition was due probably due to the presence of defective-interfering particles and was not detected with A/Leningrad/134/17/57 or A/Leningrad/134/47/57 in cultures of either line infected at the same multiplicities. Yields for both A/Leningrad/134/47/57 and B/USSR/60/69 in cells of the MDCK line were comparable when grown in six-well cultures or cell factories.     

Relationship between surface antigens of two variants of influenza A (H3N2) virus, as revealed by hemagglutination inhibition, kinetic neutralization, and neuraminidase inhibition.

Rabbit antisera were raised against plaque-purified influenza virus strains of A/Victoria/75 and A/Texas/77 isolated from Seattle influenza patients. The antigenic specificity of hemagglutinins was compared by hemagglutination inhibition (HI) and kinetic neutralization tests. Anti-A/Victoria/75 had equally high HI titers and neutralization rate constants (kappa values) for A/Victoria/75 and A/Texas/77. In contrast, anti-A/Texas/77 had a high HI titer and kappa value to A/Texas/77 and a low HI titer and kappa value to A/Victoria/75. Similar results were obtained with antisera to recombinants with hemagglutinin specific for A/Victoria/3/75 or A/Texas/1/77 and with irrelevant neuraminidase. Seven wild-type isolates, three each of A/Texas and A/Victoria, and one strain characterized as a bridging strain were tested by HI and kinetic neutralization. Characterization as A/Texas or A/Victoria was confirmed by the results. No significant difference in neuraminidase specific for A/Victoria/75 or A/Texas/77 was hown when recombinants with an irrelevant hemagglutinin were compared by the neuraminidase inhibition test. These results suggest that A/Victoria/75 strains are "senior" to A/Texas/77 strains. The epidemiological implications of this observation are discussed.     

Two-Character Chinese Compound Word Processing in Chinese Children With and Without Dyslexia: ERP Evidence

Using event-related potential (ERP) measures, we examined the time course of Chinese compound word processing in 15 dyslexic and 10 normal children in a lexical decision task with three conditions including real words (e.g., (house)), reversed nonwords (e.g., can be transposed to a real word (ocean)) and random nonwords (e.g., is not a real word when transposing). Behavioral results showed that dyslexic children performed slower and less accurately than normal children did across conditions. ERP data revealed that normal children exhibited significant N400 effects across conditions. The dyslexics did not show any difference on N400, however, suggesting a possible weakness of morphological processing in dyslexic children.     

Evolution of influenza polymerase: nucleotide sequence of the PB2 gene of A/Chile/1/83 (H1N1)

Summary The complete nucleotide sequence of the PB2 gene of influenza virus A/Chile/1/83 (H1N1) is presented. Sequence comparison between A/Chile PB2 protein and the known PB2 sequences of the influenza strains A/WSN/33 (H1N1), A/PR/8/34 (H1N1), A/NT/60/68 (H3N2), A/Kiev/59/79 (H1N1), A/FPV/Rostock/34 (H7N1), and B/Ann Arbor/1/66 indicates extensive amino acid homology for the influenza A virus PB2 proteins. Small clusters of basic amino acids are conserved in all PB2 proteins including the influenza B PB2 protein which has only 39% sequence homology overall to the PB2 polypeptides of type A influenza viruses. The evolutionary rate of 5.7 × 10^–3 nucleotide substitutions per site per year and 0.25% amino acid changes per year between the A/Chile/1/83 and A/NT/60/68 PB2 appears to be higher than that calculated earlier for A/NT, A/PR/8 and A/WSN. An unusually high degree of sequence change between A/Chile/1/83 and A/Kiev/59/79 PB2 polymerase was revealed and this is discussed in terms of its probable origin.     

Experimental assessment of the pathogenicity of eight avian influenza A viruses of H5 subtype for chickens, turkeys, ducks and quail

Clinical signs, death, virus excretion and immune response were measured in 2-week-old chickens, turkeys, quail and ducks infected by intramuscular, intranasal and contact routes with eight influenza viruses of H5 subtype. Six of the viruses: A/chicken/Scotland/59 (H5N1), ck/Scot; A/tern/South Africa/61 (H5N3), tern/SA; A/turkey/Ontario/ 7732/66 (H5N9); ty/Ont; A/chicken/Pennsylvania/1370/83 (H5N2); Pa/1370; A/turkey/Ireland/83 (H5N8); ty/Ireland, and A/duck/Ireland/ 113/84 (HSN8); dk/Ireland, were highly pathogenic for chickens and turkeys. Two viruses, A/chicken/Pennsylvania/1/83 (H5N2), Pa/1 and A/turkey/Italy/ZA/80 (H5N2), ty/Italy, were of low pathogenicity. Ck/Scot was more pathogenic for chickens than turkeys while ty/Ont was more pathogenic for turkeys than chickens. Other viruses showed little difference in their pathogenicity for these two hosts. No clinical signs or deaths were seen in any of the infected ducks. Only two viruses, dk/Ireland and ty/Ireland, produced consistent serological responses in ducks, although intramuscular infection with tern/SA and ty/Italy resulted in some ducks with positive HI titres. These four were the only viruses reisolated from ducks. Quail showed some resistance to viruses which were highly pathogenic for chickens and turkeys, most notably to ck/Scot and ty/Ont and to a lesser extent tern/SA and Pa/1370. Transmission of virus from intranasally infected birds to birds placed in contact varied considerably with both host and infecting virus and the various combinations of these.     

三氧化二砷/锰锌铁氧体复合纳米粒体外治疗食管癌

背景：与传统的热疗方法相比,As₂O₃/Mn_0.5Zn_0.5Fe₂O₄复合纳米粒可以同时发挥As₂O₃的细胞毒性作用和磁感应加热的联合定向治疗作用,效果优于单一治疗。 目的：制备As₂O₃/Mn_0.5Zn₀.₅Fe₂O₄复合纳米粒,观察其对食管癌Eca109细胞增殖的抑制作用。 方法：采用浸渍法制备As₂O₃/Mn₀.₅Zn_0.5Fe2O4复合纳米粒,含砷量0.012%,以透射电镜、能谱仪、原子分光光度仪对其进行表征。向两块培养板的食管癌Eca109细胞中分别加入DMEM培养液(阴性对照)、Mn_0.5Zn_0.5Fe₂O₄纳米材料、含As₂O₃终浓度5 μmol/L的As₂O₃/Mn_0.5Zn_0.5Fe₂O₄复合纳米粒、游离As₂O₃(终浓度5 μmol/L),其中一块培养板进行磁流体热疗,另一块培养板正常培养。 结果与结论：As2O3/Mn_0.5Zn_0.5Fe₂O₄复合纳米粒近似球形,As₂O₃成功浸渍在Mn_0.5Zn_0.5Fe₂O₄纳米材料表面,砷含量在0.012%-0.066%之间。当As₂O₃浓度为5 μmol/L时,As₂O₃/Mn_0.5Zn_0.5Fe₂O₄复合纳米粒组细胞增殖率明显低于阴性对照组和Mn_0.5Zn_0.5Fe₂O₄纳米材料组(P < 0.05);而在磁流体热疗中,As₂O₃/Mn_0.5Zn_0.5Fe₂O₄复合纳米粒组细胞增殖率明显低于游离As₂O₃组或Mn_0.5Zn_0.5Fe₂O₄组(P < 0.05);在凋亡率检测中,As₂O₃/Mn_0.5Zn_0.5Fe₂O₄复合纳米粒联合磁流体热疗组细胞凋亡率明显高于Mn_0.5Zn_0.5Fe₂O₄纳米材料联合磁流体热疗组或游离As₂O₃组(P < 0.05)。表明As₂O₃/Mn_0.5Zn_0.5Fe₂O₄复合纳米粒联合磁流体热疗可显著抑制食管癌细胞增殖。     

Genetic and biological characterization of avian influenza H5N1 viruses isolated from wild birds and poultry in Western Siberia

Three viruses included in the study were isolated from dead birds (A/duck/Omsk/1822/2006, A/chicken/Reshoty/02/2006, and A/duck/Tuva/01/2006), whereas the virus A/common gull/Chany/P/2006 was isolated from an apparently healthy gull during outbreaks of highly pathogenic avian influenza in Russia in 2006. The intravenous pathogenicity index (IVPI) of viruses A/duck/Omsk/1822/2006, A/chicken/Reshoty/02/2006, and A/duck/Tuva/01/2006 ranged from 2.7 to 3.0, while the virus A/common gull/Chany/P/2006 had a markedly lower IVPI of 1.7. The virus A/common gull/Chany/P/2006 had a unique pattern of six amino acid substitutions in the regions of viral proteins crucial for virulence of H5N1 viruses. We hypothesize that these substitutions may affect the pathogenicity of A/common gull/Chany/P/2006.     

Expression and Subcellular Localization of Recombinant SDF-1 and Its Mutant Intrakine in Transfected COS-7 Cells

INTRODUCTION The CXC chemokine stromal cell -derived factor1(SDF-1) , a member of CXC-chemokine family,is the ligand for CXCR4 and binds CXCR4 with high affinity.The interaction of SDF-1 and CXCR4 mayinduce cytoskeletal rearrangement, adhesive to endothelial cells and directional migration. SDF-1 bind-ing to CXCR4 can activiate multiple signaling pathways and produce different physiology or pathologyeffects. Compelling evidence is accumulating HIV infection and tumor metastas…     

Molecular basis of functional voltage-gated K+ channel diversity in the mammalian myocardium

In the mammalian heart, Ca²⁺-independent, depolarization-activated potassium (K⁺) currents contribute importantly to shaping the waveforms of action potentials, and several distinct types of voltage-gated K⁺ currents that subserve this role have been characterized. In most cardiac cells, transient outward currents, I _to,f and/or I _to,s, and several components of delayed reactivation, including I _Kr, I _Ks, I _Kur and I _K,slow, are expressed. Nevertheless, there are species, as well as cell-type and regional, differences in the expression patterns of these currents, and these differences are manifested as variations in action potential waveforms. A large number of voltage-gated K⁺ channel pore-forming (α) and accessory (β, minK, MiRP) subunits have been cloned from or shown to be expressed in heart, and a variety of experimental approaches are being exploited in vitro and in vivo to define the relationship(s) between these subunits and functional voltage-gated cardiac K⁺ channels. Considerable progress has been made in defining these relationships recently, and it is now clear that distinct molecular entities underlie the various electrophysiologically distinct repolarizing K⁺ currents (i.e. I _to,f, I _to,s, I _Kr, I _Ks, I _Kur, I _K,slow, etc.) in myocyardial cells.     

Method for the cross protection of mice in studying the antigenic variability of the influenza virus

A modification of the method of cross protection of mice was developed for the study of influenza virus antigenic drift. This modification does not require a pre-adaptation of the virus to mouse lungs. The experiments of cross protection of immune animals carried out by the modified method demonstrated antigenic variability of the influenza A virus strains (H3N2) isolated in 1968-1983. Immunologically significant differences between influenza A/Hong Kong/68/ and A/Victoria/36/72 virus strains were detected. Subsequently, with isolation of more influenza virus strains immunologically significant differences were found between A/Victoria/36/72 and A/Leningrad/42/75 (an analogue of A/Scotland/840/74) strains, A/Leningrad/42/75 and A/Leningrad/399/76 (an analogue of A/Victoria/3/75) strains. The differences between influenza A/Texas/1/77 and A/Leningrad/527/80 (an analogue of A/Bangkok/1/79), A/Leningrad/385/80 (an analogue of A/Bangkok/1/79), and A/Leningrad/50/83, (an analogue of A/Philippines/2/82) strains were not immunologically significant.     

Radioimmunological analysis of the neuraminidase of influenza virus subtype N2

Competitive radioimmunoassay in the homologous system using 125I-labeled neuraminidase (NA) of A/Japan/305/57 virus and antibodies to it showed that influenza viruses NA of subtypes H2N2 (A/Singapore/1/57 and A/Tokyo/3/67) and H3N2 (A/Aichi/2/68, A/England/42/72, A/Port Chalmers/1/73, and A/Texas/1/77) had undergone clear antigenic change despite the presence of Japan strain NA determinant. The use of a heterologous system (125I-NA of the Japan strain--antibodies to NA of England/42/72 strain) for the study of the intratype determinant showed the presence of a common determinant in all the strains under study, this determinant being represented dissimilarly, however. Neuraminidase of the Texas strain has a determinant differing from the intratype one, common for the Japan and England viruses.     

Electrolyte Levels in Neoplastic and Nonneoplastic Human Urothelium After Ouabain Treatment: X-Ray Microanalysis of Bulk Hydrated Samples

Samples of neoplastic and nonneoplastic human urothelium were immediately frozen, incubated in Krebs' saline and then frozen, or incubated in 10^-5 mol/L ouabain in Krebs' saline and then frozen. The frozen specimens were then planed in a cryoultramicrotome and examined by low-temperature scanning electron microscopy. X-Ray microanalysis was performed on the superficial urothelial cells. Neoplastic cells immediately frozen and those incubated in Krebs' saline had significantly higher K⁺/Na⁺, K⁺/P, and K⁺/Cl^- ratios and lower Na⁺/P and Cl^-/P ratios than nonneoplastic cells. Incubation in ouabain led to a fall in the K⁺/Na⁺, K⁺/P, and K⁺/Cl^- ratios and a rise in the Na⁺/P and Na⁺/Cl^- ratios in both neoplastic and nonneoplastic cells and effectively nullified the difference between them. These results are consistent with the concept that in neoplasia a primary event is stimulation of Na⁺/H⁺ exchange, which leads to secondary stimulation of the ouabain-sensitive Na⁺/K⁺ ATPase pump.     

Molecular specificity of a monoclonal anti-Ik alloantibody identifying a highly conserved determinant on mouse I-A, I-E and human DR antigens

We have investigated, using serological and biochemical assays, the specificity of an A.TH anti-A.TL-derived monoclonal antibody (mAb), designated 40.B, directed at a highly conserved antigenic determinant expressed on the majority of murine and human MHC class II antigens. In the mouse, mAb 40.B defines a new specificity expressed on the Ia products of the H-2 haplotypes k, d, b, v, r, p, u, j and w3. Analysis of its reactivity with H-2 recombinant strains and the results of the competitive binding inhibition of ¹²⁵I-labeled mAb 40.B to B10.BR cells with I-A^k and I-E^k specific mAb suggested recognition of a shared Ia determinant expressed on both I-A^k and I-E^k molecules. This has been confirmed by sequential immunoprecipitation studies which demonstrated the specificity of mAb 40.B for the A_β^k A_α^k, A_β^b A_α^b, A_β^d A_α^d, E_β^k E_α^k, E_β^s E_β^k, and E_β^d E_α^d dimers. In humans, this mAb bound to and immunoprecipitated HLA-D/DR molecules expressed on lymphoblastoid cell lines carrying the MTl and MT2 supertypic specificities. The possible implications of these findings with regard to an evolutionary model of MHC class II antigens are discussed.     

Intracellular calcium signalling in magnocellular neurones of the rat supraoptic nucleus: understanding the autoregulatory mechanisms

Oxytocin and vasopressin, released at the soma and dendrites of neurones, bind to specific autoreceptors and induce an increase in [Ca²⁺]₁. In oxytocin cells, the increase results from a mobilisation of Ca²⁺ from intracellular stores, whereas in vasopressin cells, it results mainly from an influx of Ca²⁺ through voltage-dependent channels. The response to vasopressin is coupled to phospholipase C and adenylyl-cyclase pathways which are activated by V₁ (V_1a and V_1b)- and V₂-type receptors respectively. Measurements of [Ca²⁺]₁ in response to V_1a and V₂ agonists and antagonists suggest the functional expression of these two types of receptors in vasopressin neurones. The intracellular mechanisms involved are similar to those observed for the action of the pituitary adenylyl-cyclase-activating peptide (PACAP). Isolated vasopressin neurones exhibit spontaneous [Ca²⁺]₁ oscillations and these are synchronised with phasic bursts of electrical activity. Vasopressin modulates these spontaneous [Ca²⁺]₁ oscillations in a manner that depends on the initial state of the neurone, and such varied effects of vasopressin may be related to those observed on the electrical activity of vasopressin neurones in vivo.     

Effect of the KCNQ potassium channel opener retigabine on single KCNQ2/3 channels expressed in CHO cells

KCNQ2/3 potassium channel subunits were co-expressed in Chinese hamster ovary (CHO) cells and currents through single channels recorded using cell-attached patches. Channels had a similar slope conductance in the presence (8.04 ± 0.02 pS) and absence (7.6 ± 0.01 pS) of 10 μ m retigabine. The mean maximal open probability ( P _o) for single KCNQ2/3 channels was 0.13 ± 0.02, with a half-maximal P _o potential ( V _o) of −28.7 ± 1.4 mV for control recordings. Retigabine increased mean maximal P _o to 0.38 ± 0.04 and produced a hyperpolarising shift of V _o to −40.1 ± 3.4 mV. Single KCNQ2/3 channels have multiple voltage-dependent kinetic components in their activity (C_L-O_S-C_M-O_L-C_S; C = closed, O = open, L = long, S = short, M = medium), giving short, medium and long closed times (τ_CS, τ_CM, τ_CL) and short and long open times (τ_OS and τ_OL). In the presence of retigabine at 0 mV the combined duration and contributions of the longest closed time τ_CL decreased tenfold, while the short and long open times increased fourfold and twofold, respectively. Thus, steady-state kinetics were modified to favour the open channel configuration.     

Variation in 5' Promoter Region of the APOE gene Contributes to Predicting Ischemic Heart Disease (IHD) in the Population at Large: the Copenhagen City Heart Study

The objective of this study was to evaluate whether an increased hazard of developing ischemic heart disease (IHD) is associated with any of the three genotypes A₅₆₀T₈₃₂/A₅₆₀T₈₃₂, A₅₆₀T₈₃₂/A₅₆₀G₈₃₂ and A₅₆₀T₈₃₂/T₅₆₀T_832, defined by variations in two non-coding SNPs in the 5' promoter region of the apolipoprotein E ( APOE) gene. These genotypes were selected because they distinguished between high and low levels of HDL-C, TG and/or T-C in our earlier study of multiple samples defined by gender and population. We found a significant increase (p<0.05) in the hazard of IHD in females with the A₅₆₀T₈₃₂/T₅₆₀T₈₃₂ genotype that remained significant after fitting the effects of dyslipidemia, other established risk factors, and the structural isoform variations of the ApoE molecule. We discuss why this statistically significant genetic predictor may not be an appropriate screening test for IHD in the Danish population at large.     

Phylogenic analysis of Chinese Leishmania isolates based on small subunit ribosomal RNA (SSU rRNA) and 7 spliced leader RNA (7SL RNA)

The leishmaniases are zoonotic diseases caused by protozoan parasites of the genus Leishmania. Leishmaniases are still endemic in China, especially in the west and northwest froniter regions. To revalue the preliminary phylogenetic results of Chinese Leishmania isolates, we amplified partial fragment of small subunit ribosomal RNA (SSU rRNA) and 7 spliced leader RNA (7SL RNA), then tested the phylogenetic relationships among Chinese Leishmania isolates and their relatives by analyzing SSU rRNA gene sequences and 7SL RNA gene sequences. 19 SSU RNA sequences and 9 7SL RNA sequences were obtained in our study, then analyzed with 42 SSU RNA sequences and 32 7SL RNA sequences retrieved from Genbank, respectively. In the Bayesian analysis of the SSU RNA gene, the isolate MHOM/CN/93/GS7 and the isolate IPHL/CN/77/XJ771 are members of Leishmania donovani complex, while the isolate MHOM/CN/84/JS1 clustered with Leishmania tropica. The other 11 Chinese Leishmania isolates (MHOM/CN/90/WC, MCAN/CN/90/SC11, MHOM/CN/80/XJ801, MHOM/CN/85/GS4, MHOM/CN/84/SD1, MCAN/CN/86/SC7, MHOM/CN/54/#3, MHOM/CN/83/GS2, MHOM/CN/90/SC10H2, MHOM/CN/89/GS6 and MHOM/CN/ 89/GS5) form an unclassified group, defined as Leishmania sp., and the most relative species to this group is L. tarentolae. In the Bayesian analysis of the 7SL RNA gene, 9 Chinese Leishmania isolates also formed an unclassified group with L. tarentolae, including canine isolate 10, MHOM/CN/85/GS4, MHOM/CN/84/SD1, MCAN/CN/86/SC7, MHOM/CN/54/#3, MHOM/ CN/83/GS2, MHOM/CN/90/SC10H2, MHOM/CN/89/GS6 and MHOM/CN/89/GS5. We concluded that: (1) Chinese Leishmania isolates are non-monophyly group; (2) an unclassified group may exist in China, and the most relative species to this group is L. tarentolae; (3) MHOM/CN/84/JS1, which was previously assigned as L. donovani, was most genetically related to L. tropica strain MHOM/SU/74/K27.