flu
[Microcirculation and hemostasis in influenza and acute viral respiratory infections complicated with pneumonia]

[Article in Russian]

Bogomolov BP, Deviatkin AV.

AIM: To study microcirculation (MC), hemostasis and blood viscosity (BV) in influenza and acute respiratory viral infections (ARVI) complicated by pneumonia. MATERIAL AND METHODS: Conjunctival biomicroscopy, hemostasis and BV were studied in 232 patients with influenza and ARVI. In 91 of them the disease complicated with acute pneumonia (AP), in 87--with obstructive bronchitis. RESULTS: Irrespectively of the disease course, patients with influenza and ARVI showed intravascular changes in MC system, hypercoagulation, deterioration of fibrinolysis. In convalescence platelet aggregation increased, fibrinolytic blood activity enhanced. In influenza and ARVI complicated with AP intravascular changes and hypercoagulation were most pronounced. In uncomplicated influenza and ARVI accompanied by bronchitis such changes are less severe. BV was the highest in development of AP. CONCLUSION: MC and hemostatic disorders arising in influenza and ARVI seem to be essential pathogenetic links provoking development of AP. In intravascular aggregation of platelets and red cells, activation of plasmic hemostasis differentiated treatment with desaggregants and anticoagulants are indicated.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11980121&dopt=Abstract flu, influenza



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Depression of chemiluminescence response in mouse spleen cells by infective and inactivated influenza virus.

Masihi KN, Lange W, Muller S.

The effect on respiratory burst of murine splenic cells after exposure to influenza viruses was studied by luminol-dependent chemiluminescence (CL). Infectious influenza A and B viruses considerably depressed the zymosan-induced CL response of the cells. Commercially available trivalent influenza virus vaccines also depressed CL activity. The whole-virus vaccine induced the greatest inhibition of the CL response, followed by the subunit and the split-virus vaccines. Virus-induced depression of CL was observed in the unseparated and in the granulocyte-enriched populations but no apparent effect was found in the lymphocyte-enriched populations. Prior sensitization of mice with representative, inactivated prototype strains of human influenza A and B viruses depressed the moderate CL induced by infectious influenza viruses. These results indicate that both infectious and inactivated influenza viruses impair the generation of the respiratory burst.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=6478654&dopt=Abstract flu, influenza



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[Detection of influenza virus A antigens by radioimmunological methods in patients' nasopharyngeal washings]

[Article in Russian]

Demidova SA, Zakharova LG, Rovnova ZI, Isaeva EI, Poliakova TG.

9olid-phase radioimmunoassay (SPRIA) was used for the detection of influenza A (H3N2,H1N1) and B viruses in nasopharyngeal washings of patients admitted in January-March, 1983, to the 1st Clinical Hospital of Moscow City with acute respiratory diseases. The solid phase consisted of nitrocellulose filters and plastic plates which were coated with nasopharyngeal washings of the patients. Rabbit or horse antiviral immunoglobulins were used as antibodies. 125I-labeled protein A was the indicator system. In 61 out of 211 patients examined influenza A (H3N2) virus was detected; from 20 of the influenza A (H3N2), from 7 influenza A (H1N1) virus was isolated, but no influenza B virus was ever found. Comparisons of the results of SPRIA and IF techniques yielded similar but not identical data. Diagnostic rises of antibodies were demonstrated in 48 out of 61 patients. The lack of complete correlation between antibody rises and detection of influenza A virus antigen appears to be due to early discharge of the patients when humoral immunity had not reached its peak. The SPRIA is a highly sensitive and specific technique for influenza A virus detection in nasopharyngeal washings of the patients and may be recommended for use in properly equipped laboratories where highly specific hyperimmune sera are available. It gives an objective information on the proportion of influenza in the period of epidemic rise of ARD incidence.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=6495704&dopt=Abstract flu, influenza



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Influenza A virus enhances the human polymorphonuclear leukocyte chemoluminescence response without effecting inhibition by trifluoperazine.

Peterson MW, Busse WW.

Influenza A virus has been demonstrated to enhance superoxide generation and chemoluminescence (CL) in human polymorphonuclear leucoytes (PMNs) under in vitro conditions. Although the mechanisms of virus-enhanced neutrophil activity is not established, calmodulin concentrations are known to increase in some virus-transformed cells. In the following experiments, we evaluated the PMN response to the calmodulin-inhibitor trifluoperazine (TFP) after an incubation with influenza A virus. Human PMNs were isolated from whole blood and were incubated with either influenza A virus (at 50% egg-infective dose per 1 leukocyte) or noninfected allantoic fluid. After incubation with influenza virus, the CL response of isolated PMNs to opsonized zymosan particles was measured. The influenza virus-treated PMNs had a mean (+/- SEM, n = 16) increase in light emission of 59.5 +/- 7.7%. TFP, in concentrations of 6 micron, 8 micron, and 10 microM, inhibition of CL was similar in influenza virus and allantoic fluid-treated neutrophils. These data suggest that, although the influenza A virus enhanced the PMN "respiratory burst" to opsonized zymosan particles, it did not alter the cell response to one calmodulin inhibitor, TFP.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=6501748&dopt=Abstract flu, influenza



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Development of an enzyme-linked immunosorbent assay (ELISA) for the detection of specific antibodies against an H7N7 and an H3N8 equine influenza virus.

Denyer MS, Crowther JR, Wardley RC, Burrows R.

This paper describes a solid-phase microtitre plate enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies to equine influenza viruses. Using egg-grown influenza viruses as the antigens attached to the solid phase, cross-reactions were observed between an H7N7 equine virus (designated A1) and an H3N8 equine influenza virus (designated A2) when untreated antisera were tested. Absorption of antisera with egg-grown A/Porcine/Shope/1/33 influenza virus eliminated cross-reactive antibodies so that specific detection of anti-equine influenza A1 or A2 antibodies was possible. Examination of horse sera following vaccination with A1 and/or A2 isolates showed that antibodies were produced against antigen associated with egg allantoic fluid as well as against virus. Such antibodies were eliminated following the absorption of antisera with porcine influenza virus. Results using sera from horses with known vaccination histories confirmed that the ELISA preferentially detected antibodies homologous to the antigen attached to the solid phase and methods to evaluate the current serological state of individual horses by relating the titres of specific antibodies against equine influenza A1 and A2 isolates are shown. This ELISA provides a simple and rapid method of assessing specific antibodies from horse sera and offers advantages over the 'routine' HI and SRH assessments since it gives high precision, is economical of reagents and has the capacity to handle large numbers of serum samples.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=6512260&dopt=Abstract flu, influenza



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Evaluation of the Directigen FluA+B test for rapid diagnosis of influenza virus type A and B infections.

Chan KH, Maldeis N, Pope W, Yup A, Ozinskas A, Gill J, Seto WH, Shortridge KF, Peiris JS.

Department of Microbiology, The University of Hong Kong and Queen Mary Hospital, Pokfulam, Hong Kong, SAR.

Directigen FluA+B (BD Diagnostic Systems, Sparks, Md.), a new rapid test for the detection of influenza virus types A and B, was evaluated with nasopharyngeal aspirate specimens collected from 250 patients in comparison with culture and direct fluorescent antigen (DFA) detection tests. The patients studied were predominantly children, 80% being </=6 years old. Specimens negative by culture but positive by the Directigen FluA+B or DFA tests were analyzed by reverse transcription-PCR to resolve the discrepant results. The resolved sensitivity, specificity, and positive and negative predictive values of the Directigen FluA+B test for influenza virus type A were 96%, 99.6%, 96%, and 99.6%, respectively, and for influenza virus type B they were 87.5%, 96.8%, 80%, and 98%, respectively. Storage of nasopharyngeal aspirates in virus transport medium at 2 to 8 degrees C for 48 h had little adverse effect on the detection of influenza virus type A, but diagnosis of influenza virus type B is best carried out with fresh specimens. The test detected a range of human and animal influenza virus A subtypes, including the H5N1 and H9N2 viruses that recently caused human disease in Hong Kong.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11980941&dopt=Abstract flu, influenza



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Complete nucleotide sequence of the influenza C/California/78 virus nucleoprotein gene.

Nakada S, Creager RS, Krystal M, Palese P.

The complete nucleotide sequence of RNA segment 5 of the influenza C/California/78 (C/Cal/78) virus was determined by using cloned cDNA derived from viral RNA. The gene contains 1809 nucleotides and can code for a protein of 565 amino acids with a molecular weight of 63 525. The RNA 5 protein of the influenza C/Cal/78 virus possesses two short regions which share a high degree (60-83%) of sequence homology with the nucleoproteins of influenza A and B viruses. These and other structural features of the RNA 5 protein suggest that RNA 5 of influenza C viruses codes for the nucleoprotein. The data also suggest that influenza C viruses are orthomyxoviruses, but that they are more distantly related to either type A or type B viruses than are influenza A and B viruses to each other.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=6532006&dopt=Abstract flu, influenza



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Modulation of human natural killer cytotoxicity by influenza virus and its subunit protein.

Ali SA, Rees RC, Oxford J.

The influence of intact influenza virus and purified detergent solubilized haemagglutinin (HA) subunits from these viruses on human natural killer (NK) cell activity was examined. Effector cells incubated with whole influenza virus for 18 hr initiated the production of alpha interferon which was associated with the enhancement of NK cell activity. In contrast, purified influenza virus HA suppressed NK activity in a dose-dependent manner, when added at the onset of the cytotoxicity assay, or when used to pre-treated effector cells prior to assay for cytotoxicity against K562 target cells. Effector cells exposed to influenza HA for 90 min, washed and re-incubated in fresh medium for up to 18 hr, failed to regain their cytotoxicity. Suppression of NK cell cytotoxicity could not be ascribed to direct toxicity of HA preparations or residual detergent and preservative in these preparations. The augmented cytotoxicity of activated human effector cells was also susceptible to suppression by virus HA, and pretreatment of human PBL effector cells with HA for 90 min, prior to exposure to human alpha interferon caused NK effector cells to become refractive to the enhancing effects of HIFN. That direct interaction between influenza virus HA and effector cells was a requirement for suppression of activity was shown in experiments using Bromelain-released influenza HA, which would not be expected to bind to cells and which failed to suppress NK cell activity.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=6746000&dopt=Abstract flu, influenza



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Detection of influenza antigen with rapid antibody-based tests after intranasal influenza vaccination (FluMist).

Ali T, Scott N, Kallas W, Halliwell ME, Savino C, Rosenberg E, Ferraro M, Hohmann E.

Infectious Diseases Division, Massachusetts General Hospital, Boston, Massachusetts 02114-2696, USA.

Rapid tests for influenza antigen detection are frequently used, but it is not known how receipt of intranasal influenza vaccine affects results of these tests. We tested healthy adults who received either intranasal or intramuscular influenza vaccine. Of the 14 intranasal vaccine recipients, 7 (50%) had a direct fluorescent antibody test (DFA) result and 2 (14%) had an enzyme immunoassay (EIA) result that was positive for influenza antigen within 7 days after vaccination. No subjects had positive EIA results on day 12 or 13 after vaccination. For some intranasal vaccine recipients, rapid influenza-antigen detection tests yield positive results within 1 week after vaccination.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=14986264&dopt=Abstract flu, influenza



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The anti-influenza virus agent 4-GU-DANA (zanamivir) inhibits cell fusion mediated by human parainfluenza virus and influenza virus HA.

Greengard O, Poltoratskaia N, Leikina E, Zimmerberg J, Moscona A.

Department of Pediatrics, Mount Sinai School of Medicine, New York, New York 10029, USA.

4-GU-DANA (zanamivir) (as well as DANA and 4-AM-DANA) was found to inhibit the neuraminidase activity of human parainfluenza virus type 3 (HPF3). The viral neuraminidase activity is attributable to hemagglutinin-neuraminidase (HN), an envelope protein essential for viral attachment and for fusion mediated by the other envelope protein, F. While there is no evidence that HN's neuraminidase activity is essential for receptor binding and syncytium formation, we found that 4-GU-DANA prevented hemadsorption and fusion of persistently infected cells with uninfected cells. In plaque assays, 4-GU-DANA reduced the number (but not the area) of plaques if present only during the adsorption period and reduced plaque area (but not number) if added only after the 90-min adsorption period. 4-GU-DANA also reduced the area of plaques formed by a neuraminidase-deficient variant, confirming that its interference with cell-cell fusion is unrelated to inhibition of neuraminidase activity. The order-of-magnitude lower 50% inhibitory concentrations of 4-GU-DANA (and also DANA and 4-AM-DANA) for plaque area reduction and for inhibition in the fusion assay than for reducing plaque number or blocking hemadsorption indicate the particular efficacy of these sialic acid analogs in interfering with cell-cell fusion. In cell lines expressing influenza virus hemagglutinin (HA) as the only viral protein, we found that 4-GU-DANA had no effect on hemadsorption but did inhibit HA2b-red blood cell fusion, as judged by both lipid mixing and content mixing. Thus, 4-GU-DANA can interfere with both influenza virus- and HPF3-mediated fusion. The results indicate that (i) in HPF3, 4-GU-DANA and its analogs have an affinity not only for the neuraminidase active site of HN but also for sites important for receptor binding and cell fusion and (ii) sialic acid-based inhibitors of influenza virus neuraminidase can also exert a direct, negative effect on the fusogenic function of the other envelope protein, HA.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11070006&dopt=Abstract flu, influenza



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Susceptibility of human influenza viruses from Australasia and South East Asia to the neuraminidase inhibitors zanamivir and oseltamivir.

Hurt AC, Barr IG, Hartel G, Hampson AW.

WHO Collaborating Centre for Reference and Research on Influenza, 45 Poplar Road, Parkville, Vic. 3052, Australia. Aeron_Hurt csl.com.au

Human influenza viruses isolated from Australasia (Australia and New Zealand) and South East Asia were analysed to determine their sensitivity to the NA inhibitor drugs, zanamivir and oseltamivir. A total of 532 strains isolated between 1998 and 2002 were tested using a fluorescence-based assay to measure the relative inhibition of NA activity over a range of drug concentrations. Based on median IC50 values, influenza A viruses (with neuraminidase subtypes N1 and N2) were more sensitive to both the NA inhibitors than were influenza B strains. Influenza A viruses with a N1 subtype and influenza B strains both demonstrated a greater sensitivity to zanamivir than to oseltamivir carboxylate, whereas influenza A strains with a N2 subtype were more susceptible to oseltamivir carboxylate. For each of the neuraminidase types, IC50 values for viruses from Australasia and South East Asia were found to be comparable. Based on the data prior to and following the licensing of the drugs into the respective regions, the use of the NA inhibitors did not appear to have a significant impact on the susceptibility of the viruses tested to zanamivir or oseltamivir carboxylate.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15026200&dopt=Abstract flu, influenza