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Abramson JS, Baker CJ, Fisher MC, Gerber MA, Meissner HC, Murray DL, Overturf GD, Prober CG, Rennels MB, Saari TN, Weiner LB, Whitley RJ. Possible association of intussusception with rotavirus vaccination. American Academy of Pediatrics. Committee on Infectious Diseases. Pediatrics 1999; 104:575. [PMID: 10469790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/13/2023] Open
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179
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Abramson JS, Givner LB. Bacterial resistance due to antimicrobial drug addiction among physicians. Time for a cure! ARCHIVES OF FAMILY MEDICINE 1999; 8:79-80. [PMID: 9932076 DOI: 10.1001/archfami.8.1.79] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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180
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Abramson JS, Holland ME. Off label use of antimicrobial agents in infants, children and adolescents: a time for action. Pediatr Infect Dis J 1998; 17:739-44. [PMID: 9726350 DOI: 10.1097/00006454-199808000-00014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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181
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Abramson JS. Society for Pediatric Research presidential address 1996: Star Wars empiricism--will the empire (SPR) strike back? Pediatr Res 1996; 40:784-9. [PMID: 8947951 DOI: 10.1203/00006450-199612000-00002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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182
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Abramson JS, Mizrahi T. When social workers and physicians collaborate: positive and negative interdisciplinary experiences. SOCIAL WORK 1996; 41:270-281. [PMID: 8936083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Interdisciplinary collaboration is becoming increasingly important as the current complexity and cost of health care require an efficient and well-coordinated service delivery system. To understand the factors contributing to positive and negative collaboration, 53 social workers and 50 physicians in 12 hospital settings were interviewed about their best and worst experiences collaborating on a case. Thirty precoded items were classified into three constructs that reflect aspects of collaboration related to the case, to interaction between collaborators, and to the competence of the collaborator. Differences between the two professions were greatest on the interactional factors, with social workers valuing them much more than physicians did. Communication appeared to be the only intrinsic or universal aspect of collaboration equally important to both groups in both types of cases. Implications for social work practice and leadership are discussed.
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183
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Abramson JS, Hudnor HR. Decreased binding of specific monomeric and trimeric G-proteins with the plasma membrane of polymorphonuclear leukocytes exposed to influenza A virus. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 1995; 155:2571-8. [PMID: 7650387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Influenza A virus (IAV)-induced polymorphonuclear leukocyte (pMNL) dysfunction is important in causing secondary bacterial infections that lead to most influenza-related deaths. We previously showed that PMNLs exposed to IAV followed by a variety of stimuli (e.g., FMLP, PMA) demonstrate inhibition of various activation steps and endstage functions, suggesting IAV alters an early step in cell signalling. The present study examined IAV's effect on trimeric and monomeric G-proteins, since alterations of these proteins could explain IAV-induced PMNL dysfunction to various stimuli. PMNLs exposed to IAV for 30 min had decreased membrane-associated basal and high affinity guanosine triphosphatase (GTPase) activity compared with control cells. immunoblotting studies, using trimeric G-protein alpha and beta subunit-specific Abs, showed IAV decreased plasma membrane association of the trimeric G-proteins alpha subunits Gi2 and Gq by 33% +/- 5 and 46% +/- 8, respectively; binding of Gi3 and Gs was not altered. Similar studies involving monomeric G-proteins demonstrated that IAV decreased the membrane binding of rap1A (35% +/- 4), but not rac G-proteins. Corresponding increases in these IAV-altered G-proteins were detected in intracellular compartments. These data suggest the mechanism of IAV-induced PMNL dysfunction involves alterations in the binding of trimeric and monomeric G-proteins to plasma membranes.
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184
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Abramson JS, Hudnor HR. Decreased binding of specific monomeric and trimeric G-proteins with the plasma membrane of polymorphonuclear leukocytes exposed to influenza A virus. THE JOURNAL OF IMMUNOLOGY 1995. [DOI: 10.4049/jimmunol.155.5.2571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
Influenza A virus (IAV)-induced polymorphonuclear leukocyte (pMNL) dysfunction is important in causing secondary bacterial infections that lead to most influenza-related deaths. We previously showed that PMNLs exposed to IAV followed by a variety of stimuli (e.g., FMLP, PMA) demonstrate inhibition of various activation steps and endstage functions, suggesting IAV alters an early step in cell signalling. The present study examined IAV's effect on trimeric and monomeric G-proteins, since alterations of these proteins could explain IAV-induced PMNL dysfunction to various stimuli. PMNLs exposed to IAV for 30 min had decreased membrane-associated basal and high affinity guanosine triphosphatase (GTPase) activity compared with control cells. immunoblotting studies, using trimeric G-protein alpha and beta subunit-specific Abs, showed IAV decreased plasma membrane association of the trimeric G-proteins alpha subunits Gi2 and Gq by 33% +/- 5 and 46% +/- 8, respectively; binding of Gi3 and Gs was not altered. Similar studies involving monomeric G-proteins demonstrated that IAV decreased the membrane binding of rap1A (35% +/- 4), but not rac G-proteins. Corresponding increases in these IAV-altered G-proteins were detected in intracellular compartments. These data suggest the mechanism of IAV-induced PMNL dysfunction involves alterations in the binding of trimeric and monomeric G-proteins to plasma membranes.
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185
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Abramson JS, O'Shea TM, Ratledge DL, Lawless MR, Givner LB. Development of a vaccine tracking system to improve the rate of age-appropriate primary immunization in children of lower socioeconomic status. J Pediatr 1995; 126:583-6. [PMID: 7699537 DOI: 10.1016/s0022-3476(95)70354-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We conducted a randomized, controlled trial to determine the effectiveness of an immunization tracking system designed to increase the number of infants of lower socioeconomic status who receive their primary series of vaccinations at age-appropriate times. By 7 months of age, 91% (274/301) of the infants in the intervention group were up-to-date on their primary series of vaccinations versus 72% (214/296) of the infants in the control group (p < 0.0001). The estimated cost of follow-up for each infant in the intervention group was $18.05.
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186
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Abramson JS, Hudnor HR. Role of the sialophorin (CD43) receptor in mediating influenza A virus-induced polymorphonuclear leukocyte dysfunction. Blood 1995; 85:1615-9. [PMID: 7888680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Polymorphonuclear leukocytes (PMNLs) exposed to influenza A virus (IAV) undergo activation of the respiratory burst followed by depression of cell function when subsequently exposed to particulate or soluble stimuli. The effect of IAV on PMNLs is likely to be mediated through the attachment of IAV to one or more specific receptors. Recently, IAV has been shown to bind to the sialophorin protein (CD43) receptor on PMNL plasma membranes. The present study was performed to determine if the sialophorin receptor was responsible for IAV-induced PMNL dysfunction. When PMNLs were incubated with IAV or CD43 monoclonal antibody (MoAb) for 30 minutes and then exposed to a secondary particulate (opsonized zymosan) or soluble (FMLP or phorbol 12-myristate 13-acetate) stimulus, there was significant depression of the PMNL chemiluminescence response compared with the equivalent control (P < .05). When PMNL were incubated with the CD43 MoAb and then cross-linked with a goat antimouse IgG antibody, no depression of PMNL function occurred upon secondary stimulation. Exposure of cells to IAV aggregates also eliminated the PMNL dysfunction that normally occurs due to the virus. Similar to IAV, PMNL dysfunction due to the CD43 MoAb could be overcome by priming the cells with granulocyte-macrophage colony-stimulating factor. These findings indicate that IAV-induced PMNL dysfunction is mediated, at least in part, through the sialophorin receptor.
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187
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Abramson JS, Wheeler JG. Virus-induced neutrophil dysfunction: role in the pathogenesis of bacterial infections. Pediatr Infect Dis J 1994; 13:643-52. [PMID: 7970955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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188
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Abramson JS, Hudnor HR. Effect of priming polymorphonuclear leukocytes with cytokines (granulocyte-macrophage colony-stimulating factor [GM-CSF] and G-CSF) on the host resistance to Streptococcus pneumoniae in chinchillas infected with influenza A virus. Blood 1994; 83:1929-34. [PMID: 7511443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Patients infected with influenza A virus (IAV) are at increased risk for bacterial superinfections, and this occurs in association with depressed polymorphonuclear leukocyte (PMNL) function. Recently, we reported that in vitro exposure of human PMNL to granulocyte-macrophage colony-stimulating factor (GM-CSF) reverses IAV-induced cell dysfunction. The present study used an established animal model of IAV infection to examine whether G-CSF and/or GM-CSF can overcome IAV-induced PMNL dysfunction and thereby prevent secondary infections. Preliminary studies determined a dosing schedule of these cytokines that caused significant priming of chinchilla PMNL. In subsequent studies, animals were inoculated intranasally with IAV (day 1) followed 3 days later by Streptococcus pneumoniae, and administered daily intraperitoneal injections with a cytokine or placebo on days 3 through 9. Animals had blood obtained on multiple occasions for PMNL studies, and were followed-up for evidence of pneumococcal disease. Both cytokines caused significant priming of the PMNL chemiluminescence response and this was associated with reversal of the IAV-induced PMNL dysfunction. However, neither cytokine decreased the incidence of pneumococcal disease.
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Givner LB, Woods CR, Abramson JS. The practice of pediatrics in the era of vaccines effective against Haemophilus influenzae type b. Pediatrics 1994; 93:680-1. [PMID: 8134231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
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190
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Abramson JS, Givner LB, Woods CR. Bismuth in infants with watery diarrhea. N Engl J Med 1993; 329:1742; author reply 1743. [PMID: 8232479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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191
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Washburn LK, O'Shea TM, Gillis DC, Block SM, Abramson JS. Response to Haemophilus influenzae type b conjugate vaccine in chronically ill premature infants. J Pediatr 1993; 123:791-4. [PMID: 8229493 DOI: 10.1016/s0022-3476(05)80862-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Twenty-two premature infants with chronic lung disease (median gestational age 28 weeks) received polyribosylribitol phosphate-outer membrane protein conjugate Haemophilus vaccine at 2 and 4 months of chronologic age. The proportions with antibodies to polyribosylribitol phosphate at levels > 1 microgram/ml after doses 1 and 2 were 27% and 55%; geometric mean titers were 0.43 and 0.73 microgram/ml, significantly lower than values for term infants.
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Abramson JS, Donnelly J, King MA, Mailick MD. Disagreements in discharge planning: a normative phenomenon. HEALTH & SOCIAL WORK 1993; 18:57-64. [PMID: 8444373 DOI: 10.1093/hsw/18.1.57] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The process of discharge planning is often impeded by disagreements among family members and others involved. A discharge plan must be negotiated to meet the varying needs of participants within the context of regulatory and organizational mandates. Under such circumstances, disagreements in decision making can be anticipated, particularly for family members, who must readjust roles and relationships in the face of the crisis of illness. Support for this conceptual formulation is found in the literature, particularly in two studies that evaluated the incidence of disagreements in discharge planning caseloads. In both studies, disagreements occurred in at least one-third of the cases, with most disagreements involving family members. Neither study found substantial disagreement among professionals. Social workers who provide discharge planning services in hospitals clearly are dealing with substantial levels of disagreements among principals in the process; in fact, disagreement needs to be accepted as a normative phenomenon in such planning. This article discusses the sources of family disagreements related to discharge planning, identifies the implications for social work practice, and uses a family systems perspective to articulate an approach to intervention.
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Sherertz RJ, Gledhill KS, Hampton KD, Pfaller MA, Givner LB, Abramson JS, Dillard RG. Outbreak of Candida bloodstream infections associated with retrograde medication administration in a neonatal intensive care unit. J Pediatr 1992; 120:455-61. [PMID: 1538298 DOI: 10.1016/s0022-3476(05)80920-5] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
An outbreak of candidemia involving five infants receiving total parenteral nutrition in the neonatal intensive care unit was investigated. Cultures of the intravenous fluids demonstrated that the retrograde medication syringe fluids were significantly more likely to be contaminated with Candida than were other fluids being administered to the infants (p less than 0.001). Candidemia was significantly associated with total parenteral nutrition (p = 0.04) and retrograde medication administration (p = 0.02). A survey of nursing practice found that reuse of the retrograde syringes was the most likely cause of contamination. Molecular typing showed that the strains of Candida albicans that were isolated from the bloodstream were also found in the retrograde syringes and that at least three strains of C. albicans and one strain each of Candida tropicalis and Candida parapsilosis were involved. In vitro growth curves demonstrated that Candida species had a selective growth advantage versus bacteria in the total parenteral nutrition fluid. An in vitro simulation of the retrograde medication administration system suggested that the outbreak probably developed after the frequency of changing intravenous tubing was decreased from every 24 hours to every 72 hours. The outbreak was terminated by using syringes only once and resuming intravenous tubing changes every 24 hours. Retrograde medication administration in association with total parenteral nutrition may increase the risk of Candida line infection.
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194
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Abramson JS, Wagner MP, Ralston EP, Wei Y, Wheeler JG. The ability of polymorphonuclear leukocyte priming agents to overcome influenza A virus-induced cell dysfunction. J Leukoc Biol 1991; 50:160-6. [PMID: 2072033 DOI: 10.1002/jlb.50.2.160] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The major mortality and morbidity resulting from influenza virus infections are due to secondary bacterial infections which occur in association with virus-induced inhibition of polymorphonuclear leukocyte (PMNL) function. The present study was undertaken to determine if compounds which prime PMNL function to subsequent stimulation with N-formylmethionyl-leucylphenylalanine (FMLP) or phorbol 12-myristate 13-acetate (PMA) can overcome influenza A virus (IAV)-induced inhibition of the PMNL chemiluminescence response to these stimuli. Granulocyte-macrophage colony stimulating factor (GM-CSF), guanosine triphosphate (GTP), and 1-oleoyl-2-acetylglycerol (OAG) were able to prime the PMNL response to FMLP and/or PMA and totally or partially overcome IAV-induced PMNL dysfunction in cells stimulated with FMLP or PMA. A direct correlation was found between the extent of PMNL priming due to GM-CSF, GTP, and OAG and the capacity of these compounds to overcome virus-induced PMNL dysfunction. The implications of these findings in regard to the mechanism by which priming agents overcome IAV-induced cell dysfunction and the potential of these compounds as therapeutic agents to treat secondary bacterial infections are discussed.
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195
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Givner LB, Abramson JS, Wasilauskas B. Apparent increase in the incidence of invasive group A beta-hemolytic streptococcal disease in children. J Pediatr 1991; 118:341-6. [PMID: 1999773 DOI: 10.1016/s0022-3476(05)82144-4] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Recently, among adults, an increase in the incidence of invasive disease caused by group A beta-hemolytic streptococci (GABS) has been noted, as has the appearance of a severe illness called "toxic shock-like syndrome," also caused by GABS. We now report an apparent increase beginning in 1987 in the incidence of invasive disease caused by GABS in children. Among these patients the manifestations were varied. One child had signs and symptoms compatible with the streptococcal toxic shock-like syndrome. Among the GABS isolates from our patients, 8 (80%) of 10 evaluated for M-protein antigens were nontypeable. Further studies will be necessary to determine the relationship between serotypes and virulence of GABS. Physicians should be aware of the possibility of an increasing incidence of invasive GABS disease in children, as well as its manifestations, which may include toxic shock-like syndrome.
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Abramson JS, Givner LB. Should tetracycline be contraindicated for therapy of presumed Rocky Mountain spotted fever in children less than 9 years of age? Pediatrics 1990; 86:123-4. [PMID: 2359669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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198
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Wheeler JG, Winkler LS, Seeds M, Bass D, Abramson JS. Influenza A virus alters structural and biochemical functions of the neutrophil cytoskeleton. J Leukoc Biol 1990; 47:332-43. [PMID: 2319207 DOI: 10.1002/jlb.47.4.332] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Influenza A virus (IAV) has previously been shown to alter chemotactic, oxidative, and secretory functions of polymorphonuclear leukocytes (PMNL). Because of the role of cytoskeletal proteins in these processes, studies were carried out to determine if IAV altered the PMNL cytoskeleton. PMNL were incubated with buffer of IAV, stimulated with f-met-leu-phe (FMLP), fixed and stained with NBD-phallacidin (NBD-Ph) and studied by flow cytometry. Mean F-actin fluorescence was increased 18% in virus treated cells pre-FMLP stimulation and 13% 5 and 10 min post-FMLP (P less than .03); no significant difference in F-actin fluorescence was noted in virus treated PMNL 15-30 s post-FMLP compared to control cells. PMNL exposed to the same conditions were solubilized and actin content was determined following SDS-PAGE of triton insoluble precipitates. Increased actin was recovered from virus treated compared to buffer treated cells before and after FMLP stimulation in the 8,000g precipitates (P less than .001). Immunofluorescent microscopy studies of F-actin distribution were done in PMNL stained with NBD-Ph following FMLP stimulation for 10 min. These studies showed an increased lamellipod F-actin/uropod F-actin ratio in PMNL pre-incubated with IAV compared to controls (4.6 vs. 1.0; P less than .025). Phosphorylation of specific cytoskeletal proteins was examined after immunoprecipitation. IAV alone altered phosphorylation of both vimentin and vinculin, and in stimulated PMNL virus led to decreased phosphorylation of vimentin and vinculin. These data show distributional and biochemical effects of IAV on PMNL cytoskeletal proteins, indicating additional targets for IAV interference in the PMNL signal-transduction-function process.
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199
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Cassidy LF, Lyles DS, Abramson JS. Depression of polymorphonuclear leukocyte functions by purified influenza virus hemagglutinin and sialic acid-binding lectins. THE JOURNAL OF IMMUNOLOGY 1989. [DOI: 10.4049/jimmunol.142.12.4401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
Infection of polymorphonuclear leukocytes (PMNL) with influenza virus causes depression of PMNL metabolic and bactericidal activities. The studies reported here were undertaken to determine whether the hemagglutinin (HA) glycoprotein of influenza virus mediates this depression. PMNL were incubated with purified HA and the oxidative responses to exogenous stimuli were measured. The results indicate that HA, in either liposomes or protein aggregates referred to as rosettes, depressed PMNL oxidative responses. Depression was observed within 2 min of initial interaction of HA with PMNL and lasted more than 2 h. The membrane fusion activity of HA requires proteolytic cleavage of the HA, whereas the receptor binding activity does not. There was no difference in the ability of virions with cleaved or uncleaved HA to depress PMNL responses suggesting that the fusion event is not required for PMNL dysfunction. Inasmuch as the HA glycoprotein binds to sialic acid-containing receptors on the surface of the PMNL, we tested whether other sialic acid-specific binding proteins can mediate the reduction of PMNL responses. Sialic acid-specific lectins from Limulus polyphemus or Limax flavus were incubated with PMNL before measuring their responses to secondary stimulus. Depression was observed upon incubation with the lectins similar to that seen upon incubation with the HA or influenza virus. These results suggest that attachment of influenza virus to sialic acid-containing receptors is responsible at least in part, for suppressing PMNL oxidative responses.
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200
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Cassidy LF, Lyles DS, Abramson JS. Depression of polymorphonuclear leukocyte functions by purified influenza virus hemagglutinin and sialic acid-binding lectins. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 1989; 142:4401-6. [PMID: 2723434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Infection of polymorphonuclear leukocytes (PMNL) with influenza virus causes depression of PMNL metabolic and bactericidal activities. The studies reported here were undertaken to determine whether the hemagglutinin (HA) glycoprotein of influenza virus mediates this depression. PMNL were incubated with purified HA and the oxidative responses to exogenous stimuli were measured. The results indicate that HA, in either liposomes or protein aggregates referred to as rosettes, depressed PMNL oxidative responses. Depression was observed within 2 min of initial interaction of HA with PMNL and lasted more than 2 h. The membrane fusion activity of HA requires proteolytic cleavage of the HA, whereas the receptor binding activity does not. There was no difference in the ability of virions with cleaved or uncleaved HA to depress PMNL responses suggesting that the fusion event is not required for PMNL dysfunction. Inasmuch as the HA glycoprotein binds to sialic acid-containing receptors on the surface of the PMNL, we tested whether other sialic acid-specific binding proteins can mediate the reduction of PMNL responses. Sialic acid-specific lectins from Limulus polyphemus or Limax flavus were incubated with PMNL before measuring their responses to secondary stimulus. Depression was observed upon incubation with the lectins similar to that seen upon incubation with the HA or influenza virus. These results suggest that attachment of influenza virus to sialic acid-containing receptors is responsible at least in part, for suppressing PMNL oxidative responses.
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