| in vivo priming of cytotoxic t lymphocyte responses in relation to in vitro up-regulation of major histocompatibility complex class i molecules by short synthetic peptides. | cytotoxic t lymphocytes (ctl) recognize target antigens as short peptides presented by major histocompatibility complex class i molecules (mhc-i). externally added peptides can sensitize target cells by binding directly to mhc-i without any need for internal processing. those which are similar in length to endogenously processed peptides are more potent in this respect than slightly longer peptides. peptide mhc-i interactions can also be reflected as up-regulation of mhc-i in vitro on certain ce ... | 1992 | 1446701 |
| induction of primary anti-viral cytotoxic t cells by in vitro stimulation with short synthetic peptide and interleukin-7. | the present study investigated whether a short synthetic peptide npp, with a modified sequence (147-158 r156-) derived from influenza a virus nucleoprotein with high affinity for kd major histocompatibility complex class i molecules, could induce primary influenza virus-specific cytotoxic t (tc) cells in vitro. naive balb/c (h-2d) splenocytes did not respond to the stimulation with only npp with the generation of effector tc cells specific for influenza a virus-infected target cells in vitro. ho ... | 1992 | 1446709 |
| influenza a outbreaks in nursing homes. | | 1992 | 1447451 |
| influence of amantadine resistance mutations on the ph regulatory function of the m2 protein of influenza a viruses. | mutations in the influenza m2 membrane protein which confer resistance to the antiviral drug amantadine are exclusively located within the transmembrane region of the molecule. the influence of specific amino acid substitutions on the activity of the m2 protein in influenza a virus-infected cells is assessed in this report by their effects upon haemagglutinin (ha) stability and virus growth. a number of amino acid substitutions, e.g., l26h, a30t, s31n and g34e reduced the activity of the m2 prot ... | 1992 | 1448912 |
| suppression of plasmodium falciparum infections during concomitant measles or influenza but not during pertussis. | in tropical countries, concomitant infections are a continuous problem. in the rufiji delta, an area of tanzania that is holoendemic for malaria, there were outbreaks of influenza a, measles, and pertussis in 1986 and 1987. significantly lower parasitic prevalences and mean densities of malaria parasites were found in children up to nine years of age who had measles or influenza than in asymptomatic control children. in contrast, children with pertussis had a higher prevalence and mean density t ... | 1992 | 1449208 |
| western blot analysis of antibody responses to influenza virion proteins. | an immunoblotting procedure was developed to detect antibody responses in mice and humans to influenza virion proteins. the technique was capable of detecting 1.5 micrograms of haemagglutinin (ha) on nitrocellulose strips at a 1:5000 dilution of a mouse serum with an initial haemagglutination inhibition titre of 20. the effects of the use of the blocking agent tween-20 on virion proteins were also studied. the commonly used concentration of 0.05% (v/v) tween-20, when included in blocking and inc ... | 1992 | 1452221 |
| structural basis of antigenic variation: studies of influenza virus neuraminidase. | | 1992 | 1452222 |
| high growth reassortant influenza vaccine viruses: new approaches to their control. | when a new strain of an influenza virus is required to be incorporated into influenza vaccine, attempts are made to recombine such strains with laboratory adapted viruses, which will grow to high titre in order to improve the yield of the vaccine strain. it is important that such high growth reassortant vaccine strains are not contaminated with genes coding for the antigenic determinants of the high growth laboratory strain. we describe the characterization of two recent high growth reassortants ... | 1992 | 1457106 |
| influenza in the world. 1 october 1991-30 september 1992. | | 1992 | 1457338 |
| anti-influenza virus activity of a lignin fraction from cone of pinus parviflora sieb. et zucc. | when mice were inoculated intranasally or intracerebrally with lethal doses of influenza virus a/wsn/33, most died within 12 days. however, the infectivity of virus that had been preincubated with a lignin prepared from cones of pinus parviflora sieb. et zucc. (pc-fr. vi) was significantly reduced. intraperitoneal or oral administration of pc-fr. vi, prior to virus inoculation, slightly increased the survival ratio of the infected mice. experiments using radiolabeled pc-fr. vi revealed that this ... | 1992 | 1457741 |
| update: influenza activity--united states and worldwide, 1992-93 season. | influenza activity in the united states is monitored by cdc through surveillance systems maintained cooperatively with state and local health departments (1); in addition, cdc receives reports of worldwide influenza activity from international world health organization (who) collaborating laboratories and from who, geneva. this report summarizes surveillance for influenza in the united states and worldwide during the 1992-93 season through december 5, 1992. | 1992 | 1461251 |
| influenza vaccination in chronic hemodialysis patients. the effect of zinc supplementation. | since influenza increases the mortality of chronically ill patients we decided to study the effectiveness of influenza vaccination in hemodialysis (hd) patients. nineteen hd patients aged from 20 to 60 years, on unrestricted diet and with no febrile episode, were studied. blood samples were collected before the intramuscular injection of 0.5 ml multivalent influenza vaccine (inflexal berna) and every 2 weeks thereafter. at the end of 4th week a second vaccination was done and a dosage of 200 mg ... | 1992 | 1462010 |
| influenza--its impact and control. | influenza is an underestimated public health problem. epidemics spread rapidly from country to country and may affect as many as 500 million people across the world in a moderate influenza year. the disease, particularly influenza a, kills and the new influenza viruses which appeared in 1957 (asian influenza) and 1968 (hong kong) are estimated to have caused at least 100,000 deaths in the united states of america. deaths from influenza also occur in years when there is no new virus; at least 10, ... | 1992 | 1462665 |
| the influence of dextran sulfate on influenza a virus fusion with erythrocyte membranes. | dextran sulfate suppresses the low ph-induced fusion of influenza virus a/brazil 11/78 with erythrocyte membranes, as shown by fluorescence dequenching assay, using the fluorophore octadecylrhodamine b chloride (r18). inhibition of fusion was maximal at ph 5.0, while at higher ph values (> 5.6) fusion was not affected. hemolysis of intact red blood cells by influenza a virus at low ph values is also prevented by dextran sulfate. the inhibiting effect of the polymer is mainly ascribed to repressi ... | 1992 | 1463322 |
| [influenza, the elderly and amantadine]. | | 1992 | 1464395 |
| pneumonia--a clinical or radiographic diagnosis? etiology and clinical features of lower respiratory tract infection in adults in general practice. | etiology and clinical manifestations have been studied in 153 adult patients with lower respiratory tract infection, and the results are presented according to clinical and radiographic diagnosis. laboratory investigations revealed that bacterial infection, mycoplasma and chlamydia included, occurred as often in 22 patients whose clinical diagnoses of pneumonia were not evident radiographically, as in 20 patients with radiographic pneumonia. in the latter group significantly higher values of ery ... | 1992 | 1465584 |
| [experimental influenzal and tuberculous infections under conditions of specific and nonspecific immunosuppression]. | the course of influenza and tuberculosis infections under the conditions of disturbances in the immune response of experimental animals has been studied. as revealed in the survival test, the induction of secondary t- and b-cell-mediated immunodeficiency in mice leads to an increase in the sensitivity of the body to influenza virus, especially in cases of t-cell-mediated immunodeficiency. the injection of bcg in combination with cyclophosphamide into mice induces tolerance to this antigen in the ... | 1992 | 1466173 |
| specificity of the proteus antibody response in rheumatoid arthritis. | antibodies to proteus were determined by indirect immunofluorescence in 146 serum samples from patients with rheumatoid arthritis (ra). an autoantibody screen was performed in the same samples and in 52 of these antibody titres to the viruses influenza a, adenovirus, rubella, and parvovirus were determined. there was no significant correlation between proteus antibodies and any of the other antibodies tested. dividing the samples into those from patients with active (c reactive protein > 10 mg/l ... | 1992 | 1466597 |
| a pathogenesis study of highly pathogenic avian influenza virus h5n2 in chickens, using immunohistochemistry. | eighteen specific pathogen-free chickens (nine hens older than 1 year and nine 15-week-old males) were inoculated with highly pathogenic avian influenza virus a/chicken/pennsylvania/1370/1983 (h5n2). birds were serially killed and tissues collected for histological and immunohistochemical evaluation. in the group of older hens, disease was acute or peracute. by immunohistochemistry, antigen was abundant in capillary endothelium in multiple organs, and staining for antigen in parenchymal cells wa ... | 1992 | 1469128 |
| nucleotides 9 to 11 of the influenza a virion rna promoter are crucial for activity in vitro. | the 12 nucleotide conserved sequence at the 3' end of influenza a virion rna is sufficient to function as a promoter in vitro. by introducing point mutations in all 12 positions of this promoter in model rna templates and studying the efficiency of rna synthesis in vitro, we show that only three nucleotides, residues 9, 10 and 11, are crucial for activity, although other nucleotides play a significant but less important role. additions or deletions within the promoter are tolerated, resulting in ... | 1992 | 1469351 |
| binding of influenza a virus ns1 protein to dsrna in vitro. | the non-structural protein ns1 of influenza a virus exhibits two modes of rna-binding activity. one is sequence-specific binding to minus-sense virus rna with either a 5'- or 3'-terminal common sequence as reported previously. the other was identified as binding to dsrna and this activity did not show sequence specificity. the affinity of binding to dsrna was much higher than that to ssrna. a short miniature virion rna forming a panhandle structure by pairing between the 5'- and 3'-terminal comm ... | 1992 | 1469370 |
| [low protection against this winter's influenza. a repeat performance of last season's subtype a?]. | | 1992 | 1469973 |
| [laboratory problems of chemotherapy of viral infections in humans]. | the following problems are presented and discussed: scientific and epidemiologic basis of chemotherapy, relations of antiviral activity in vitro and in vivo especially important when new-drugs are developed and evaluated, inhibitors used in medical treatment and mechanisms of their antiviral functions, genesis and nature of virus resistance, possible role of interfering defective particles. the paper is addressed both to laboratories involved in new drugs construction as well to clinical ones pe ... | 1992 | 1470577 |
| [a study of potassium-conserving diuretic preparations for their antiviral activity in respect to the influence virus]. | | 1992 | 1471343 |
| immunopotentiating reconstituted influenza virosomes (irivs) and other adjuvants for improved presentation of small antigens. | synthetic peptides, purified subunits or inactivated small virus particles require immunopotentiation if they are to be effective vaccines. a large range of procedures to enhance immunogenicity has evolved over the last decades: aluminium salts, proteosomes, immunostimulating complexes (iscoms), liposomes, conjugation with bacterial products or derivatives, combination with surface-active agents or application of cytokines have been the most described classes of adjuvants. we describe here the d ... | 1992 | 1471412 |
| [influenza--1990]. | | 1992 | 1475393 |
| detection of influenza a and b in respiratory secretions with the polymerase chain reaction. | influenza a and b are rna-containing viruses that frequently infect humans. currently, sensitive detection of these viruses requires fresh respiratory secretions and special facilities for culture. to facilitate diagnosis of influenza, the polymerase chain reaction (pcr) was used in the present studies to detect dna produced by reverse transcription of influenzal rna in vaccines, tissue culture fluids, and stored respiratory secretions. primers were directed at targets on the highly conserved se ... | 1992 | 1477662 |
| the pathogenic determinant of influenza virus. | influenza viruses, like other viruses, must exhibit a genome constellation, which permits optimal virus reproduction in a given host. besides this prerequisite the influenza virus haemagglutinin glycoprotein (ha) has been shown to be an essential determinant for pathogenicity. ha, which is synthesized as a precursor molecule, is activated by posttranslational cleavage by host proteases to obtain its full biological properties. proteolytic activation is therefore indispensable for effective virus ... | 1992 | 1481363 |
| behavioral thermoregulation in mice inoculated with influenza virus. | mice housed at 30 degrees c and inoculated with a mouse-adapted influenza virus show a fall in body temperature (tb) and a decrease in food intake to almost 0 grams per day. this study tested whether the fall in tb could be accounted for by the decreased food intake and whether the fall in tb was due to a decrease of thermoregulatory set point or to an inability to maintain tb at set point level. the fall in tb of influenza-infected mice was greater than that of food-deprived mice. when food dep ... | 1992 | 1484872 |
| nephrotropic properties demonstrated by a/chicken/alabama/75 (h4n8) following intravenous challenge of chickens. | tissue tropism properties of a/chicken/alabama/75 (h4n8) were examined after intravenous inoculation of 5-week-old specific-pathogen-free chickens. from 14 clinically normal chickens euthanatized on days 1-20 postinoculation, the frequencies of virus recovery were highest for cloacal swabs (86%), bursal swabs (64%), and kidney tissues (64%) and lowest for tracheal swabs (14%), thymus tissues (14%), bone-marrow swabs (7%), and brain tissues (0%). evidence that the high frequency of virus recovery ... | 1992 | 1485875 |
| evaluation of the kidney as a potential site of avian influenza virus persistence in chickens. | one-day-old chickens were inoculated intravenously with one of three low-pathogenicity avian-origin influenza isolates. on day 5 postinoculation (pi), the frequency of influenza virus isolation from cloacal swabs following challenge with each isolate ranged from 83% to 100% for clinically normal euthanatized chickens. influenza virus was also frequently isolated from kidneys of these chickens (47%) and from chickens that died (100%). kidneys positive for virus isolation had lesions of nephrosis ... | 1992 | 1485877 |
| re-evaluation of the pathogenicity of a/chicken/alabama/75 (h4n8) influenza virus. | avian influenza (ai) virus a/chicken/alabama/7395/75 (h4n8), a putatively non-pathogenic virus associated with a self-limiting outbreak of severe disease in commercial layers, was selectively passed in chickens or in cell cultures and then in chickens to determine whether virus with increased pathogenicity would emerge. when 20 derivatives of the parental virus were each inoculated intranasally and intratracheally in leghorn hens, mortality rates ranged from zero (0/24) to 25% (6/24); mortality ... | 1992 | 1485880 |
| [concept of the mechanism of the therapeutic effect of flu chemotherapy]. | | 1992 | 1486335 |
| use of monoclonal antibodies for rapid diagnosis of respiratory viruses: memorandum from a who meeting. | a monoclonal antibody diagnostic kit (using immunofluorescence) to detect directly viral antigens of respiratory syncytial virus, influenza virus a, influenza virus b, parainfluenza viruses (types 1, 2, and 3), and adenovirus has been developed by who. during 1990 and 1991 a total of 16 laboratories in different parts of the world were invited to test the kit in clinical use. this memorandum summarizes the results obtained as well as the discussions and recommendations made by participants at a ... | 1992 | 1486665 |
| the use of hybrid-selected template increases the specificity of the polymerase chain reaction. | an efficient method for generating full-length dna sequences from apparently unsuccessful polymerase chain reactions (pcr) has been developed. in cases where nonspecific background interferes with detection of the pcr product, a second amplification is performed using a nested set of primers. the internal fragment of dna amplified in this reaction is then blotted to a membrane and used to hybrid-select the desired dna from the initial amplification. this dna is eluted and used as the template fo ... | 1992 | 1490174 |
| influenza basic polymerase 2 peptides are recognized by influenza nucleoprotein-specific cytotoxic t lymphocytes. | cytotoxic t lymphocytes (ctl) play an important role in limiting viral infections and in eradicating virus from host tissues. recent progress in understanding the processing and presentation of viral antigens to ctl indicates that the ctl antigen receptor recognizes peptides derived from viral proteins that are bound to an antigen binding groove present in class i major histocompatibility complex (mhc) molecules. in understanding ctl anti-viral responses and in creating vaccines designed to elic ... | 1992 | 1495499 |
| [usefulness and limitations of vaccination against influenza]. | influenza viruses have caused major epidemics of respiratory disease and a high mortality in patients with advanced age and in those with underlying health conditions. it has been estimated in the usa that, during a moderate epidemic of influenza, there is an excess of 170,000 hospitalizations and approximately 20,000 to 40,000 influenza-associated deaths per years. costs may exceed 1 billion dollars per year. influenza viruses have been difficult to control because of a large animal reservoir a ... | 1992 | 1496181 |
| [the correction of the functional activity of alveolar macrophages in inducing a primary immune response in influenza]. | the functional activity of alveolar macrophages obtained from mice, both healthy and infected with influenza virus a/aichi 2/68 (h3n2), as manifested by their capacity to initiate the development of primary immune response to sheep red blood cells and escherichia coli lipopolysaccharide after the transfer of these macrophages to intact syngeneic recipients was studied. the capacity of alveolar macrophages to perform antigen-presenting functions in the induction of humoral immune response was sho ... | 1992 | 1496877 |
| recombinant salmonella typhimurium strains that invade nonphagocytic cells are resistant to recognition by antigen-specific cytotoxic t lymphocytes. | to address the question of whether salmonella-infected nonphagocytic cells could serve as target cells for recognition by antigen-specific, major histocompatibility complex class i-restricted cytotoxic t lymphocytes (ctl), four recombinant salmonella typhimurium constructs that expressed full-length, or fragments of, influenza a virus nucleoprotein (np) were made. the bacteria were shown to infect chinese hamster ovary (cho) cells. appropriate major histocompatibility complex restriction molecul ... | 1992 | 1500187 |
| expression of the influenza a virus m2 protein is restricted to apical surfaces of polarized epithelial cells. | the m2 protein of influenza a virus is a small, nonglycosylated transmembrane protein that is expressed on surfaces of virus-infected cells. a monoclonal antibody specific for the m2 protein was used to investigate its expression in polarized epithelial cells infected with influenza virus or a recombinant vaccinia virus that expresses m2. the expression of m2 on the surfaces of influenza virus-infected cells was found to be restricted to the apical surface, closely paralleling that of the influe ... | 1992 | 1501289 |
| peptide binding to class i molecules of the major histocompatibility complex on the surface of living target cells. | molecules encoded by the class i major histocompatibility genes bind short (nonameric) peptides produced by intracellular proteolysis of antigens. these complexes formed intracellularly are then expressed on membranes of target cells and recognized by the antigen receptor of cytolytic t cells. no binding of externally added peptides could so far be monitored directly on the antigen presenting cells, although cytotoxicity experiments and indirect binding assays provided evidence for its existence ... | 1992 | 1502501 |
| influenza vaccine strain selection: equivalence of two antigenically distinct haemagglutinin variants of 1989 h3n2 influenza a virus in protection of mice. | precise antigenic analysis with haemagglutinin-inhibition (hi) tests of 1989 h3n2 influenza a viruses with polyclonal ferret, rabbit and mouse antisera has shown, first, significant differences among 1989 wild-type isolates, second, antigenic differences between two high-yield vaccine candidate reassortant viruses, third, significant antigenic differences of one reassortant (x-105) from the wild-type virus (a/guangdong a/39) from which it was derived, and fourth, dependence of antigenic characte ... | 1992 | 1502837 |
| enhancement of antibody response of turkeys to trivalent avian influenza vaccine by positively charged liposomal avridine adjuvant. | trivalent avian influenza (aiv) antigens (h4n8, h5n2 and h7n3), mixed with positively charged, negatively charged and neutral avridine-containing liposomes, and oil-emulsion were subcutaneously administered to 6-week-old turkeys. charged liposomal avridine adjuvant, either positive or negative, produced a better antibody response than uncharged liposomal avridine or oil-emulsion adjuvants when used in a trivalent avian influenza vaccine. the antibody response to the different antigens was genera ... | 1992 | 1502840 |
| morphological estimation of total number of influenza a type virion spikes. | when purified and stored influenza a type virions were observed by the negative staining method in electron microscopy, we found disintegrated virions associated with a population of dispersed but clustered spikes. the total spike numbers of the clusters were morphologically counted, and their peak number (about 200) was consistent with the spike number measured by the molecular biology method, described in the other report. | 1992 | 1506801 |
| synthesis and antiviral evaluation of n-carboxamidine-substituted analogues of 1-beta-d-ribofuranosyl-1,2,4-triazole-3-carboxamidine hydrochloride. | ten, hitherto unreported, analogues of 1-beta-d-ribofuranosyl-1,2,4-triazole-3-carboxamidine hydrochloride (2a, ribamidine) and methyl carboximidate 5 have been synthesized. these include the n-cyano (2b), n-alkyl (2c-e), n-amino acid (2f-h), n,n'-disubstituted (6, 7a,b), and the n-methylated carboxamide (1f) analogues of ribavirin. in addition, a new facile synthesis of carboxamidine 2a was also developed. all compounds were evaluated for biological activity against the following rna viruses: p ... | 1992 | 1507208 |
| [amantadine in influenza]. | | 1992 | 1509589 |
| [epidemiological effectiveness of an inactivated three-component flu vaccine with an increased concentration of hemagglutinin in the inoculation dose]. | the work presents the results of the evaluation of mass immunization of working adults with inactivated trivalent influenza vaccine under the conditions of an epidemic caused by influenza viruses a (h1n1), a (h3n2) and b. this immunization produced no effect on influenza morbidity in the groups of vaccinees in comparison with those of nonvaccinated persons. the index of effectiveness was 1.0 and less. the ineffectiveness of mass immunization was due to a high level of natural immunity to influen ... | 1992 | 1509849 |
| [use of highly purified subvirion trivalent flue vaccine ("grippovak") in groups with a high risk of complications]. | during the epidemic season of 1989-1990 the subunit vaccine grippovac was used in 20 asylums for old people and psychoneurological invalids in moscow for the protection of the inhabitants and the personnel from influenza. follow-up of the vaccinees during the period from november 1989 to march 1990 revealed that the use of this vaccine decreased the incidence of influenza-like diseases (ild) 3.4-4.1 times among the vaccinees in comparison with that in the nonvaccinated control groups and signifi ... | 1992 | 1509852 |
| [effect of mytilane, a bioglycan from the mussel crenomytilus grayanus, on the course and outcome of experimental flu infection]. | materials characterizing the antiviral activity of mytilane, manifested by the protection of 50-60% of mice infected with the lethal dose of influenza virus and by a decrease in the severity of pathological changes in the lungs of mice, are presented. the inhibiting activity of mytilane with respect to the reproduction of influenza virus in vivo and in vitro under experimental conditions is demonstrated. | 1992 | 1509854 |
| effects of protease inhibitors on replication of various myxoviruses. | we studied the effects of eight protease inhibitors on the multicycle replications of various orthomyxoviruses and paramyxoviruses. among the compounds, nafamostat mesilate, camostat mesilate, gabexate mesilate, and aprotinin, which are widely used in the treatment of pancreatitis, inhibited influenza virus a and b replication at concentrations that were significantly lower than their cytotoxic thresholds in vitro. none of the protease inhibitors had activity against respiratory syncytial virus, ... | 1992 | 1510439 |
| cultured human langerhans cells process and present intact protein antigens. | epidermal langerhans cells (lc) undergo profound phenotypic and functional alterations when cultured for 2 to 3 d. to determine whether the in vitro culture of human lc modulates their capacity to process and present intact protein antigens, we compared the ability of freshly isolated lc (flc) and cultured lc (clc) to stimulate in vitro t-cell proliferative responses to recall antigens. we found that human flc and clc were able to process and present recall antigens to primed t cells, inducing s ... | 1992 | 1512470 |
| influenza virus a infection induces interleukin-8 gene expression in human airway epithelial cells. | to determine the role of the airway epithelial cell in mediating virus-induced inflammation, we infected primary cultures of human airway epithelial cells with human influenza type a/port chalmers/72 (h3n2). after two days, the medium was collected for measurement of the chemotactic cytokine interleukin-8 by enzyme-linked immunosorbent assay. the rna was extracted from the cells for analysis of interleukin-8 mrna by northern blot analysis. interleukin-8 production was more than doubled by viral ... | 1992 | 1516705 |
| in vivo primary induction of virus-specific ctl by immunization with 9-mer synthetic peptides. | a primary cytotoxic t lymphocyte (ctl) response in vivo requires antigen presentation by cytosolic processing and can not in general be obtained by vaccination with soluble proteins. in the present work we have found that vaccination of mice with pre-processed synthetic peptides, corresponding to endogenous 9-mers produced in influenza a virus-infected cells, resulted in strong primary ctl responses. the generated ctl efficiently killed virus-infected target cells with preference for viral strai ... | 1992 | 1517589 |
| influenza virus hemagglutinin ha-2 n-terminal fusogenic peptides augment gene transfer by transferrin-polylysine-dna complexes: toward a synthetic virus-like gene-transfer vehicle. | complexes containing plasmid dna, transferrin-polylysine conjugates, and polylysine-conjugated peptides derived from the n-terminal sequence of the influenza virus hemagglutinin subunit ha-2 have been used for the transfer of luciferase or beta-galactosidase marker genes to k562 cells, hela cells, and bnl cl.2 hepatocytes. these dna complexes mimic the entry of viruses into cells, as they contain functions for (i) the packaging of the nucleic acid with polylysine, (ii) the attachment to the cell ... | 1992 | 1518816 |
| implications of viral resistance to amantadine in control of influenza a. | antiviral agents are valuable adjuncts to vaccine in the control of type a influenza. amantadine has been available for many years for prophylaxis and therapy, but there have been concerns about side effects, particularly in the elderly. thus, the anticipated licensure of rimantadine, an antiviral with the same efficacy as amantadine but with fewer side effects, has been viewed as a major advance. rimantadine has thus far remained unlicensed, and attention has become focused on antiviral resista ... | 1992 | 1520770 |
| crystal structures of two mutant neuraminidase-antibody complexes with amino acid substitutions in the interface. | the site on influenza virus n9 neuraminidase recognized by nc41 monoclonal antibody comprises 19 amino acid residues that are in direct contact with 17 residues on the antibody. single sequence changes in some of the neuraminidase residues in the site markedly reduce antibody binding. however, two mutants have been found within the site, ile368 to arg and asn329 to asp selected by antibodies other than nc41, and these mutants bind nc41 antibody with only slightly reduced affinity. the three-dime ... | 1992 | 1522584 |
| [amantadine and rimantadine against influenza a]. | amantadine and the analogue rimantadine have an antiviral effect on influenza a virus and are approximately 60% effective in preventing illness. the drugs are administered orally, and peak plasma concentration is achieved at two hours after a single dose. side effects occur in 5-20% of the cases, but generally mild and transient and seen mainly with doses of more than 200 mg a day. this paper describes the mechanism of action and the pharmacokinetics of the drugs, and refers to some important cl ... | 1992 | 1523633 |
| in vivo antibody response to mucosal (nasal) and subcutaneous stimulation of influenza virus in patients with iga nephropathy. | anomalies in the production of antibodies have been postulated in the development of iga nephropathy. in order to study the aberrant immune response in patients with iga nephropathy (igan), an influenza virus vaccine was administered to healthy adults and patients with igan to demonstrate if there was any in vivo alteration in the antibody production to mucosal and non-mucosal antigenic stimulation in these groups. the vaccine was administered subcutaneously (s.c) or intranasally at a dose of 35 ... | 1992 | 1523689 |
| interactions between bacteria and influenza a virus in the development of influenza pneumonia. | different proteases from various microorganisms present in the respiratory tract were capable of enhancing influenza virus infectivity and pathogenicity in mice by proteolytic activation of hemagglutinin (ha). aerococcus viridans, isolated from a patient with pneumonia, secreted a protease that could activate ha directly, similarly to some staphylococcus aureus strains. the protease of pseudomonas aeruginosa could not activate ha directly, but combined application of p. aeruginosa protease and v ... | 1992 | 1527412 |
| nuclear retention of m1 protein in a temperature-sensitive mutant of influenza (a/wsn/33) virus does not affect nuclear export of viral ribonucleoproteins. | we investigated the properties of ts51, an influenza virus (a/wsn/33) temperature-sensitive rna segment 7 mutant. nucleotide sequence analysis revealed that ts51 possesses a single nucleotide mutation, t-261----c, in rna segment 7, resulting in a single amino acid change. phenylalanine (position 79) in the wild-type m1 protein was substituted by serine in ts51. this mutation was phenotypically characterized by dramatic nuclear accumulation of the m1 protein and interfered with some steps at the ... | 1992 | 1527844 |
| internal entry of ribosomes on a tricistronic mrna encoded by infectious bronchitis virus. | mrna3 specified by the coronavirus infectious bronchitis virus appears to be functionally tricistronic, having the capacity to encode three small proteins (3a, 3b, and 3c) from separate open reading frames (orfs). the mechanism by which this can occur was investigated through in vitro translation studies using synthetic mrnas containing the 3a, 3b, and 3c orfs, and the results suggest that translation of the most distal of the three orfs, that for 3c, is mediated by an unconventional, cap-indepe ... | 1992 | 1527853 |
| maturation of influenza a virus hemagglutinin--estimates of the ph encountered during transport and its regulation by the m2 protein. | the susceptibility of h7 influenza a viruses to the m2-mediated alteration in ha resulting from treatment with amantadine or rimantadine depends both on the ph stability of ha and the ph encountered during transport to the plasma membrane of the particular virus-infected cell. ph stabilities of a range of virus mutant has exhibited an inverse correlation with drug sensitivity and the proportion of low-ph ha expressed on the surface of infected cells in the absence of drug. the lowest ph encounte ... | 1992 | 1529523 |
| location and character of the cellular enzyme that cleaves the hemagglutinin of a virulent avian influenza virus. | h.-d. klenk, w. garten, and r. rott (1984, embo j. 3, 2911-2915) have reported that hemagglutinin (ha) cleavage of virulent avian influenza viruses occurs in later steps of its intracellular transport and that the cleavage enzyme is calcium dependent and has a neutral ph optimum. the precise intracellular location of the ha cleavage, however, has never been established. furthermore, because klenk et al. used the whole cell lysate to examine the cleavage activity and the amino acid sequencing of ... | 1992 | 1529533 |
| protective efficacy of combined live intranasal and inactivated influenza a virus vaccines in the elderly. | to evaluate the efficacy of adding intranasal live attenuated cold-adapted influenza a vaccine to inactivated influenza vaccine to prevent influenza a in elderly residents of long-term-care institutions. | 1992 | 1530193 |
| mice can recover from pulmonary influenza virus infection in the absence of class i-restricted cytotoxic t cells. | intranasal exposure of athymic (nu/nu) balb/c mice to influenza virus leads to a persistent infection of the respiratory tract from which the mice die, usually within 3 to 4 wk with symptoms of general cachexia. however, if these nude mice were injected 1 day after infection, with approximately 10(6) cells from individual virus-specific mhc class ii-restricted th cell clones, they showed greatly reduced mortality and the titers of infectious virus in their lungs were reduced, often to undetectab ... | 1992 | 1530795 |
| subtype h7 influenza viruses: comparative antigenic and molecular analysis of the ha-, m-, and ns-genes. | antigenic analysis of the haemagglutinin and matrix protein with corresponding sets of monoclonal antibodies as well as sequence analysis of ha-, m-, and ns-genes were carried out to establish antigenic and genetic relationships between four fowl plague virus (fpv) strains of h7 subtype. the data obtained revealed close genetic relatedness between the oldest known influenza a virus, a/chicken/brescia/1902 (h7n7), and two fpv strains, a/fpv/dobson (h7n7) and a/fpv/weybridge (h7n7). these three st ... | 1992 | 1530908 |
| specific binding of influenza a virus ns1 protein to the virus minus-sense rna in vitro. | the non-structural protein ns1, encoded by genome segment 8 of influenza a virus, was expressed in escherichia coli from cloned cdna and purified. the ns1 protein had a specific rna-binding activity, binding to influenza a virus minus-sense but not plus-sense rna synthesized in vitro from cloned dna using phage rna polymerase. ns1 bound preferentially to the regions of rna containing either 5'- or 3'-terminal common sequences of the genomic rna. binding was inhibited by virion rna, but not by si ... | 1992 | 1530962 |
| alterations in antioxidant defences in lung and liver of mice infected with influenza a virus. | we investigated the possible involvement of oxidative mechanisms in the pathogenesis of influenza a/pr8/34 virus infection in mice. as a biochemical marker of oxidative stress, we determined the endogenous concentrations of the antioxidants glutathione and vitamins c and e in their reduced and oxidized forms in the lungs, liver and blood plasma of control and infected animals. following intranasal infection with 8 to 10 ld50, influenza virus was detected in the lungs, but not in the plasma, live ... | 1992 | 1530963 |
| biological properties of waterfowl-origin type a influenza viruses in chickens. | the replicative abilities and tissue tropism properties of 13 non-pathogenic or low-pathogenic waterfowl-origin type a influenza isolates recovered in 1986 were examined in chickens. following intravenous challenge, reisolation of challenge virus was attempted from swabs of the luminal surfaces of the cloaca, jejunum, ileum, bursa, trachea, and air sacs and from swabs of bone marrow and liver tissues. virus-isolation attempts were also accomplished on brain, thymus, spleen, pancreas, gonad, kidn ... | 1992 | 1533115 |
| analyzing the distribution of cells expressing mrna for t cell receptor gamma and delta chains in a virus-induced inflammatory process. | acute inflammatory processes are extremely complex, containing sets of activated cells that may be difficult to categorize. the interface between two methodologies for characterizing the involvement of gamma delta t cells, in situ hybridization to detect t cell receptor (tcr) mrna and flow cytometric analysis of surface tcr expression, is utilized here to study the pneumonia caused by intranasal (i.n.) infection of mice with influenza a viruses. substantial numbers of cells expressing mrna for t ... | 1992 | 1535834 |
| genetic relatedness of the nucleoprotein (np) of recent swine, turkey, and human influenza a virus (h1n1) isolates. | the sequences of nucleoprotein (np) genes of recent human and turkey isolates of influenza a viruses, which serologically could be correlated to contemporary swine viruses, were determined. these sequences were closely related to the nps of these swine viruses and they formed a separate branch on the phylogenetic tree. while the early swine virus from 1931 resembled the avian strains in consensus amino acids of the np and in its ability to rescue np ts mutants of fowl plague virus in chicken emb ... | 1992 | 1536092 |
| ph-dependent membrane fusion and vesiculation of phospholipid large unilamellar vesicles induced by amphiphilic anionic and cationic peptides. | we studied fusion induced by a 20-amino acid peptide derived from the amino-terminal segment of hemagglutinin of influenza virus a/pr/8/34 [murata, m., sugahara, y., takahashi, s., & ohnishi, s. (1987) j. biochem. (tokyo) 102, 957-962]. to extend the study, we have prepared several water-soluble amphiphilic peptides derived from the ha peptide; the anionic peptides d4, e5, and e5l contain four and five acidic residues and the cationic peptide k5 has five lys residues in place of the five glu res ... | 1992 | 1536841 |
| superior cross-protective effect of nasal vaccination to subcutaneous inoculation with influenza hemagglutinin vaccine. | intranasal (i.n.) vs. subcutaneous (s.c.) administration of influenza hemagglutinin (ha) vaccine was systematically compared in balb/c mice. mice were immunized with different vaccines, together with cholera toxin b subunit as an adjuvant, and 4 weeks later were challenged with either a small (2 microliters) or a large (20 microliters) volume of mouse-adapted a/guizhou-x (h3n2) virus, each of which gave virgin mice either a nasal or a lung predominant infection. both i.n. and s.c. inoculations o ... | 1992 | 1537382 |
| the relationship between influenza vaccine-induced specific antibody responses and vaccine-induced nonspecific autoantibody responses in healthy older women. | the effect of aging on human humoral immunity was investigated by studying in vivo the relationship between influenza specific antibody responses and nonspecific vaccine-induced autoantibody responses in 32 independent, well-nourished older women volunteers (mean age 86 yr, range 74-97) and 23 young women volunteers (mean age 34 yr, range 23-46). anti-influenza a/taiwan/1/86(h1n1) antibody titers were determined by a hemagglutination inhibition test (hi-test), and serum anti-dsdna antibodies wer ... | 1992 | 1538066 |
| human influenza a (h1n2) viruses isolated from china. | reassortant influenza a viruses bearing h1 haemagglutinin and n2 neuraminidase were isolated from humans in china between december 1988 and march 1989. as primary isolation of influenza a (h1n2) viruses from humans had not been reported previously, it was of interest to determine the genetic origin of these virus isolates. the haemagglutinins of the h1n2 viruses were antigenically and genetically related to those of h1 viruses isolated world-wide since 1986, and the neuraminidases of these virus ... | 1992 | 1538194 |
| from the centers for disease control. outbreak of influenza a in a nursing home--new york, december 1991-january 1992. | | 1992 | 1538527 |
| presentation of viral antigen by mhc class i molecules is dependent on a putative peptide transporter heterodimer. | major histocompatibility complex (mhc) class i molecules present peptides derived from the endogenous protein pool to cytotoxic t lymphocytes, which can thus recognize intracellular antigen. this pathway may depend on a transporter (psf1) to mediate entry of the cytosolic peptides into a pre-golgi compartment where they bind to class i heavy chains and promote their stable assembly with beta 2-microglobulin. there is, however, only indirect support for this function of psf1. here we show that ps ... | 1992 | 1538752 |
| [varying clinical pictures among young children with influenza virus type a infections]. | the clinical course of influenza type a virus infections in 47 hospitalized children aged 0-9 years was assessed retrospectively. the infection was diagnosed by demonstration of the virus in the nasopharyngeal secretion during the acute phase of the illness. out of 21 influenza a strains in which the subtype was determined, one was found to be h1- and 20 were h3-subtype. lower respiratory tract disease was the main diagnosis in 21 children, 16 of whom had pneumonia; 14 of these patients were und ... | 1992 | 1539390 |
| nursing home outbreak of influenza a (h3n2): evaluation of vaccine efficacy and influenza case definitions. | describe an outbreak of influenza a (h3n2); provide an analysis of vaccine efficacy; measure the sensitivity, specificity, and positive predictive value of 3 clinical case definitions of influenza. | 1992 | 1541810 |
| prevention and control of influenza a outbreaks in long-term care facilities. | | 1992 | 1545112 |
| degradation of cellular mrna during influenza virus infection: its possible role in protein synthesis shutoff. | the kinetics of cellular mrna decay in influenza virus-infected cells have been studied by means of blot hybridization using as probes cloned cdnas of alpha- and beta-actin, alpha- and beta-tubulin and vimentin. both cellular mrnas isolated from the cytoplasmic fractions as well as total cell mrnas showed a rapid decay, with up to 50% concentration reductions at infection times at which influenza virus m1 mrna was still not detectable. in contrast, these cellular mrnas were stable in uninfected ... | 1992 | 1545220 |
| structural evidence for induced fit as a mechanism for antibody-antigen recognition. | the three-dimensional structure of a specific antibody (fab 17/9) to a peptide immunogen from influenza virus hemagglutinin [ha1(75-110)] and two independent crystal complexes of this antibody with bound peptide (tyrp100-leup108) have been determined by x-ray crystallographic techniques at 2.0 a, 2.9 a, and 3.1 a resolution, respectively. the nonapeptide antigen assumes a type i beta turn in the antibody combining site and interacts primarily with the fab hypervariable loops l3, h2, and h3. comp ... | 1992 | 1546293 |
| heterogeneity of the mutation rates of influenza a viruses: isolation of mutator mutants. | the rates of mutation to the mar (monoclonal antibody-resistant) genotype of individual influenza virus plaque isolates, obtained from a stock generated after two successive cloning steps, have been determined by the fluctuation test. when a random sample of 60 clones was analyzed, 7 contained a proportion of mar mutants significantly higher than the average, and among them, 2 showed a mutation rate two to three times higher than the average value obtained for the virus population when the hemag ... | 1992 | 1548773 |
| human and mouse mx proteins inhibit different steps of the influenza virus multiplication cycle. | human mxa and mouse mx1 are interferon-induced proteins capable of inhibiting the multiplication of influenza virus. mxa protein is localized in the cytoplasm, whereas mx1 protein accumulates in the nucleus. taking advantage of stably transfected cell lines that constitutively express either mxa or mx1 protein, we examined the steps at which these proteins block influenza a viruses. in infected cells expressing mxa protein, all viral mrnas synthesized as a result of primary transcription in the ... | 1992 | 1548781 |
| acute severe deterioration in cystic fibrosis associated with influenza a virus infection. | the role of non-bacterial infection in respiratory exacerbations of cystic fibrosis has been studied less than that of bacterial infection. some non-bacterial infections, such as influenza a, may be associated with acute respiratory deterioration and may be preventable. | 1992 | 1549818 |
| evolutionary pattern of the h 3 haemagglutinin of equine influenza viruses: multiple evolutionary lineages and frozen replication. | the nucleotide and deduced amino acid sequences of the haemagglutinin genes coding for the ha 1 domain of h3n8 equine influenza viruses isolated over wide regions of the world were analyzed in detail to determine their evolutionary relationships. we have constructed a phylogenetic model tree by the neighbour-joining method using nucleotide sequences of 15 haemagglutinin genes, including those of five viruses determined in the present study. this gene tree revealed the existence of two major evol ... | 1992 | 1550498 |
| use of single-gene reassortant viruses to study the role of avian influenza a virus genes in attenuation of wild-type human influenza a virus for squirrel monkeys and adult human volunteers. | the transfer of six internal rna segments from the avian influenza a/mallard/new york/6750/78 (h2n2) virus reproducibly attenuates human influenza a viruses for squirrel monkeys and adult humans. to identify the avian influenza a virus genes that specify the attenuation and host range restriction of avian-human (ah) influenza a reassortant viruses (referred to as ah reassortants), we isolated six single-gene reassortant viruses (sgrs), each having a single internal rna segment of the influenza a ... | 1992 | 1551982 |
| immunization of infants and young children with live attenuated trivalent cold-recombinant influenza a h1n1, h3n2, and b vaccine. | seventeen triply seronegative infants and young children, and 15 infants and young children seropositive to all three influenza virus strains were vaccinated intranasally with 10(5) tcid50 of each of three (h1n1, h3n2, and b) live attenuated, cold-adapted influenza vaccine strains. seventeen controls were given placebo. vaccination with trivalent influenza vaccine was not associated with adverse reactions in triply seronegative or seropositive children. overall, 12 (71%), 13 (76%), and 13 (76%) ... | 1992 | 1552202 |
| transgenic mice lacking class i major histocompatibility complex-restricted t cells have delayed viral clearance and increased mortality after influenza virus challenge. | to investigate the role of cd8+ t lymphocytes in recovery from influenza pneumonia, we used transgenic mice either homozygous (-/-) or heterozygous (+/-) for beta 2-microglobulin (beta 2-m) gene disruption. these mice lack major histocompatibility complex-restricted class i (cd8+) t cells. we found that after challenge with a nonlethal influenza virus, the beta 2-m (-/-) mice had significantly delayed pulmonary viral clearance. furthermore, after challenge with a more virulent influenza virus, t ... | 1992 | 1552285 |
| microbial etiology of acute pneumonia in hospitalized patients. | the purpose of this study was to determine the microbial etiology of pneumonia by using strict criteria among a group of hospitalized patients. patients with acute community-acquired or hospital-acquired pneumonia were studied in a systematic and comprehensive manner for bacterial, viral, chlamydial, mycobacterial, and fungal pathogens. a total of 198 patients with 204 episodes of pneumonia were evaluated. despite 100 percent follow-up of all surviving patients, a specific etiologic agent could ... | 1992 | 1555415 |
| [virologico-serologic studies in horses with respiratory tract diseases]. | of 1081 acute and chronically respiratory diseased as well as clinically normal horses 824 sera and 257 paired serum samples collected 1986 and 1987 were tested for antibodies against several different respiratory viruses such as influenza virus a/equi 1 and 2 (influenza 1 a. 2), equine herpesvirus type 1/4 (ehv 1/4), mammalian reovirus type 1-3 (reovirus 1-3), equine rhinovirus type 1 (erv 1), equine adenovirus type 1 (eadv 1), and equine arteritis virus (eav). the investigations resulted in an ... | 1992 | 1558530 |
| human immunodeficiency virus vectors for inducible expression of foreign genes. | tat-dependent expression of an endogenous lethal or deleterious foreign gene might be useful for abrogating the production of human immunodeficiency virus (hiv) from cells. this type of hiv-induced cellular killing, as well as other approaches to gene therapy for hiv infection, would be facilitated by simple hiv vectors that express introduced genes in a tat-inducible manner. as part of studies to examine the feasibility of this concept, we constructed hiv-1 vectors that express the hygromycin b ... | 1992 | 1560523 |
| enhancement of the protective effect of inactivated influenza virus vaccine by cytokines. | the authors examined whether or not cytokines in conjunction with inactivated influenza virus vaccine enhance protection from influenza virus infection in mice. mice were infected with influenza virus a/pr/8/34 (pr/8) at 10 ld50 by nebulizer after intranasal administration of the cytokine and the vaccine. the survival rate of the group which received both the vaccine and mouse recombinant interferon-beta (muifn-beta; 1 x 10(4) iu/mouse) or mouse recombinant interferon-gamma (muifn-gamma; 1 x 10( ... | 1992 | 1561830 |
| infection enhancement of influenza a nws virus in primary murine macrophages by anti-hemagglutinin monoclonal antibody. | antibody-dependent enhancement (ade) of influenza a nws virus infection was investigated in primary murine macrophages (m phi) using anti-hemagglutinin(ha) monoclonal antibody (mab). contrary to previous reports of abortive influenza virus infection in primary m phi, this study demonstrated that the nws virus replicated productively in both resident peritoneal m phi and thioglycolate-elicited peritoneal m phi providing cleavage of the ha was achieved by trypsin; 5 micrograms/ml of trypsin was th ... | 1992 | 1564451 |
| [infectious agents associated with exacerbations of chronic obstructive bronchopneumopathies and asthma attacks]. | infections of the respiratory airways are frequently responsible for exacerbations of chronic obstructive pulmonary disease (copd) and attacks of asthma. however, the causal infectious agents in practice are rarely precisely identified. we have undertaken a prospective study with the aim of researching into the bacteria and viruses associated with these exacerbations. forty-seven patients who were in hospital between 1987 and 1989 for attacks of asthma (13 episodes) or exacerbations of copd (35 ... | 1992 | 1565831 |
| evolution of influenza a(h1n1) viruses during a period of low antigenic drift in 1986-91: sequence of the ha1 domain of influenza a/finland/158/91. | this study used the nucleotide sequence coding for the ha1 domain of virus haemagglutinin to show that influenza a/finland/158/91, which represents the h1n1 subtype viruses prevalent in finland in 1990/91, was a direct descendant of a virus (a/nn/1605/88) isolated during the 1988/89 epidemic season in japan. the elevated rate of 7.4 x 10(-3) nucleotide substitutions per site per year is discussed. the new branch of h1n1 subtype viruses is characterized by loss of a glycosylation site, which may ... | 1992 | 1565849 |
| evidence that the amantadine-induced, m2-mediated conversion of influenza a virus hemagglutinin to the low ph conformation occurs in an acidic trans golgi compartment. | amantadine treatment of cells infected with h7 strains of influenza a viruses causes an m2 protein-mediated conversion of hemagglutinin (ha) from its native to its low ph conformation. immunofluorescence and electron microscopic observations showed that the structural alteration and hence drug action occur shortly after ha exits from the golgi complex during its passage through the strans golgi region. using the damp/anti-dnp ph probe it is evident that virus infection causes increased acidity o ... | 1992 | 1566569 |
| hemagglutinin activation of pathogenic avian influenza viruses of serotype h7 requires the protease recognition motif r-x-k/r-r. | the hemagglutinin of influenza virus a/fpv/rostock/34 (h7) was altered at its multibasic cleavage site by site-directed mutagenesis and assayed for proteolytic activation after expression in cv-1 cells. the results indicated that the cellular protease responsible for activation recognizes the tetrapeptide motif r-x-k/r-r that must be presented in the correct sequence position. studies on plaque variants of influenza virus a/fowl/victoria/75 (h7n7) showed that alteration of the consensus sequence ... | 1992 | 1566583 |
| a single point mutation of the influenza c virus glycoprotein (hef) changes the viral receptor-binding activity. | from strain jhb/1/66 of influenza c virus a mutant was derived with a change in the cell tropism. the mutant was able to grow in a subline of madin-darby canine kidney cells (mdck ii) which is resistant to infection by the parent virus due to a lack of receptors. inactivation of cellular receptors by either neuraminidase or acetylesterase and generation of receptors by resialylation of cells with n-acetyl-9-o-acetylneuraminic acid (neu5,9ac2) indicated that 9-o-acetylated sialic acid is a recept ... | 1992 | 1566586 |
| sequence analysis of the equine h7 influenza virus haemagglutinin gene. | the nucleotide sequences of ten haemagglutinin genes of representative h7n7 equine influenza viruses isolated between 1956 and 1977 have been determined by primer extension sequencing. their nucleotide and deduced amino acid sequences demonstrate a high degree of homology. these equine viruses can be divided into two distinct subgroups, the prototype-like, and a group comprising the early american isolates and the remaining equine viruses. the equine h7 haemagglutinins form a quite distinct grou ... | 1992 | 1566601 |