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1.
Acta Biomed ; 94(S3): e2023123, 2023 08 30.
Artigo em Inglês | MEDLINE | ID: mdl-37695199

RESUMO

BACKGROUND AND AIM: Rolling reviews have been widely used by the scientific community during the COVID-19 pandemic to provide guidelines and identify potential treatments in such a quickly evolving emergency. Throughout the two pandemic years, we provided independent and continuously updated (rolling) e-learning courses on COVID-19 targeted to Italian healthcare professionals with the aim of increasing dissemination based on the emerging evidence. The results of this project are presented in this brief report. METHODS: We launched five main courses on COVID-19 - with focus on treatments and vaccines - from February 2020 to December 2022. For each course, we collected and analised participation data and, via questionnaires, customer-satisfaction data on relevance, quality, efficacy and sponsor perception. RESULTS: From 22 February 2020 to 31 December 2022, a total of 224,459 enrollments were registered over the five courses with 192,966 passes (86%), for which Continuing Medical Education (CME) credits were awarded. Over 94% of participants considered the contents of high quality, relevant and effective for their educational needs. The absence of sponsorship perception, 83% overall, decreased relevantly for the two courses on COVID-19 vaccines (68.3%). CONCLUSIONS: Italian healthcare professionals working during the pandemic overwhelmingly appreciated and valued the rolling e-learning offer aimed at widening the dissemination of the best practices on COVID-19. This educational model provides independent, evidence-based and tailored information with the undoubted advantages of time flexibility, remote participation and continuous update, all elements that make it a useful tool in a pandemic as well as in a post-pandemic era.


Assuntos
COVID-19 , Instrução por Computador , Humanos , Pandemias , Vacinas contra COVID-19 , Modelos Educacionais , Atenção à Saúde
2.
Dermatol Reports ; 15(1): 9500, 2023 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-37063404

RESUMO

Smartphone apps may help promoting the early diagnosis of melanoma. The reliability of specialist judgment on lesions should be assessed. Hereby, we evaluated the agreement of 6 young dermatologists, after a specific training. Clinical judgment was evaluated during 2 online sessions, 1 month apart, on a series of 45 pigmentary lesions. Lesions were classified as highly suspicious, suspicious, non-suspicious or not assessable. Cohen's and Fleiss' kappa were used to calculate intra- and inter-rater agreement. The overall intra-rater agreement was 0.42 (95% confidence interval - CI: 0.33-0.50), varying between 0.12-0.59 on single raters. The inter-rater agreement during the first phase was 0.29 (95% CI: 0.24-0.34). When considering the agreement for each category of judgment, kappa varied from 0.19 for not assessable to 0.48 for highly suspicious lesions. Similar results were obtained in the second exercise. The study showed a less than satisfactory agreement among young dermatologists. Our data point to the need for improving the reliability of the clinical diagnoses of melanoma especially when assessing small lesions and when dealing with thin melanomas at a population level.

3.
J Contin Educ Health Prof ; 40(4): 289-292, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33284182

RESUMO

INTRODUCTION: Distance learning efficacy on physician performances and patient health outcomes has been demonstrated. This study explored the participation and evaluation of CME e-learning courses for Italian health care professionals addressing leading causes of maternal mortality identified by the Italian Obstetric Surveillance System (ItOSS) at the Italian National Health Institute, namely postpartum hemorrhage and pregnancy hypertensive disorders. METHODS: A model for two online free 12-hour case-based training courses was used. Data on participants were collected, anonymized, and transferred to the Italian National Health Institute for later analysis. Participants were requested to sign an online informed consent form. RESULTS: Twenty-one thousand five hundred thirty-two health care professionals enrolled to the courses from 2014 to 2017 as follows: midwives (14,187, 65.9%); obstetricians (3,716, 17.2%); anesthesiologists (1,896, 8.8%); and other medical specialists (1,733, 8.0%). Overall, 85% of participants acquired CME credits. Participants' satisfaction on quality, efficacy, and relevance was very high. DISCUSSION: ItOSS courses were able to reach a substantial number of different professional profiles involved in perinatal care all over the country; ItOSS courses can be considered an effective way to spread evidence-based good clinical practices. Nevertheless, further studies are needed to verify the improvement in professional health care skills and patient outcomes.


Assuntos
Educação a Distância/normas , Serviços de Saúde Materna/normas , Obstetrícia/educação , Adulto , Educação a Distância/métodos , Educação a Distância/tendências , Feminino , Pessoal de Saúde/educação , Humanos , Itália , Masculino , Serviços de Saúde Materna/tendências , Pessoa de Meia-Idade , Obstetrícia/métodos
4.
Exp Cell Res ; 319(12): 1875-1888, 2013 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-23578765

RESUMO

Proton efflux via voltage-gated proton channels (Hv1) is considered to mediate the charge compensation necessary to preserve NADPH oxidase activity during the respiratory burst. Using the Hv1 inhibitor Zn(2+), we found that the PMA-induced respiratory burst of human neutrophils is inhibited when assessed as extracellular production of O2(-) and H2O2, in accordance with literature studies, but, surprisingly, unaffected when measured as oxygen consumption or total (extracellular plus intracellular) H2O2 production. Furthermore, we show that inhibiting Hv1 with Zn(2+) results in an increased production of intracellular ROS. Similar results, i.e. decreased extracellular and increased intracellular ROS production, were obtained using a human granulocyte-like cell line with severely impaired Hv1 expression. Acidic extracellular pH, which dampens proton efflux, also augmented intracellular production of H2O2. Zinc caused an increase in the rate but not in the extent of depolarization and cytosolic acidification indicating that mechanisms other than proton efflux take part in charge compensation. Our results suggest a hitherto unpredicted mechanism of charge compensation whereby, in the absence of proton efflux, part of O2(-) generated within gp91(phox) in the plasma membrane is shunted intracellularly down electrochemical gradient to dampen excessive depolarization. This would preserve NADPH oxidase activity under conditions such as the inflammatory exudate in which the acidic pH hinders charge compensation by proton efflux.


Assuntos
Canais Iônicos/antagonistas & inibidores , Neutrófilos/metabolismo , Oxigênio/metabolismo , Explosão Respiratória , Linhagem Celular Tumoral , Membrana Celular/metabolismo , Humanos , Peróxido de Hidrogênio/metabolismo , Concentração de Íons de Hidrogênio , Canais Iônicos/metabolismo , Transporte de Íons , Potenciais da Membrana , NADPH Oxidases/metabolismo , Neutrófilos/fisiologia , Prótons , Eletricidade Estática , Acetato de Tetradecanoilforbol/análogos & derivados , Acetato de Tetradecanoilforbol/farmacologia , Zinco/farmacologia
5.
Blood ; 119(5): 1214-6, 2012 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-22210873

RESUMO

Neutrophil extracellular traps (NETs) are DNA structures released by dying neutrophils and claimed to constitute a new microbicidal mechanism. Killing by NET-forming cells is ascribed to these structures because it is prevented by preincubation with DNase, which has been shown to dismantle NETs, before addition of the target microorganisms. Curiously, the possibility that the microorganisms ensnared in NETs are alive has not been considered. Using Staphylococcus aureus and Candida albicans blastospores, we demonstrate that the microorganisms captured by NETs and thought to be killed are alive because they are released and recovered in cell medium by incubation with DNase. It is concluded that NETs entrap but do not kill microbes.


Assuntos
Ativação de Neutrófilo/fisiologia , Neutrófilos/fisiologia , Candida albicans/imunologia , Candidíase/imunologia , Candidíase/patologia , Morte Celular/imunologia , Morte Celular/fisiologia , Estruturas Celulares/imunologia , Estruturas Celulares/metabolismo , Estruturas Celulares/fisiologia , Citotoxicidade Imunológica/fisiologia , Espaço Extracelular/imunologia , Espaço Extracelular/metabolismo , Folclore , Humanos , Ativação de Neutrófilo/imunologia , Neutrófilos/imunologia , Neutrófilos/metabolismo , Neutrófilos/ultraestrutura , Fagocitose/fisiologia , Infecções Estafilocócicas/imunologia , Infecções Estafilocócicas/patologia , Staphylococcus aureus/imunologia
6.
7.
Biochim Biophys Acta ; 1792(3): 201-10, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19708127

RESUMO

This article reports an atypical and extremely rare case of X-linked CGD in an Italian family characterized by a low expression of gp91phox (X91- CGD). A novel point mutation in the CYBB gene's promoter (insertion of a T at position -54T to -56T) appeared to prevent the full expression of this gene in the patient's neutrophils and correlated with a residual oxidase activity in the whole cells population. The expression and functional activity of the oxidase in eosinophils appeared to be almost normal. Gel shift assays indicated that the mutation led to decreased interactions with DNA-binding proteins. The total O2- production in the patient's granulocytes (5-7% of normal) supported no microbicidal power after 45 min and 60 min of contact with S. aureus and C. albicans, respectively. Despite this residual oxidase activity, the patients suffered from severe and life-threatening infections. It was concluded that in these X91- CGD neutrophils, the O2- production per se was not sufficient to protect the patient against severe infections.


Assuntos
Cromossomos Humanos X/genética , Doença Granulomatosa Crônica/genética , Glicoproteínas de Membrana/genética , NADPH Oxidases/genética , Neutrófilos/metabolismo , Mutação Puntual , Regiões Promotoras Genéticas/genética , Sequência de Bases , Análise Mutacional de DNA , Feminino , Humanos , Peróxido de Hidrogênio/metabolismo , Itália , Masculino , Glicoproteínas de Membrana/metabolismo , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , NADPH Oxidase 2 , NADPH Oxidases/metabolismo , Oxidantes/metabolismo , Linhagem , Alinhamento de Sequência , Superóxidos/metabolismo
8.
G Ital Med Lav Ergon ; 31(4): 371-406, 2009.
Artigo em Italiano | MEDLINE | ID: mdl-20225643

RESUMO

Starting from the experience of last five years, during which 24 guide liens about the most important aspects of Occupational Physician activity have been produced, the Italian Society of Occupational Medicine and Industrial Hygiene (SIMLII) delegated a specific working group for updating the methodology to be adopted for guide lines and other instruments for improving and standardizing the current activity in our professional field. SIMLII produced in the context of the specific Education and Accreditation Programme for occupational physicians prepared from 2002 25 guide lines or other informative instruments on the most important and controversial themes in which our discipline is involved. They were considered and treated to meet the need to improve and standardise activities and to modify the current approach of occupational physicians and aimed not only at improving the effectiveness of preventive actions but also at constantly adopting rigorous methodologies based where possible on evidence based or on consensus procedures. The Directive of SIMLII was firmly convinced about the opportunity-necessity to critically evaluate the experience carried out during the last years, at the light of the National Program for Guide Lines edited By Italian National Health Institute since 2002 and which concerns preparation, dissemination, updating, implementation of guide lines in Medicine. The guide lines were defined as rational critical effective aid addressed to professionals and patients for health services organization. Relevant was the new Framework Act for the occupational safety and health (Decreto legislativo 81/08) too signed by the President of the Italian Republic on April 9, 2008, which for the first time includes and defines in a legislative act the different possible instruments (technical normative, good practices, guide lines). In this paper we present the new methodology defined by our Society for producing the different kind of instruments such as guide lines, consensus conference reports, technology assessments, good practices statements guide lines focusing as the main aspects those related to definitions, argument choice, working group and coordinator identification, producing methods, evidence evaluation, grading, quality evaluation using AGREE method, dissemination procedure, the conflict of interest and the possible use for distance formation procedure focusing the recommendations that take a practical-applicative approach.


Assuntos
Medicina do Trabalho/normas , Guias de Prática Clínica como Assunto
9.
Implement Sci ; 3: 37, 2008 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-18637189

RESUMO

BACKGROUND: In an effort to ensure that all physicians have access to valid and reliable evidence on drug effectiveness, the Italian Drug Agency sponsored a free-access e-learning system, based on Clinical Evidence, called ECCE. Doctors have access to an electronic version and related clinical vignettes. Correct answers to the interactive vignettes provide Continuing Medical Education credits. The aims of this trial are to establish whether the e-learning program (ECCE) increases physicians' basic knowledge about common clinical scenarios, and whether ECCE is superior to the passive diffusion of information through the printed version of Clinical Evidence. DESIGN: All Italian doctors naïve to ECCE will be randomised to three groups. Group one will have access to ECCE for Clinical Evidence chapters and vignettes lot A and will provide control data for Clinical Evidence chapters and vignettes lot B; group two vice versa; group three will receive the concise printed version of Clinical Evidence. There are in fact two designs: a before and after pragmatic trial utilising a two by two incomplete block design (group one versus group two) and a classical design (group one and two versus group three). The primary outcome will be the retention of Clinical Evidence contents assessed from the scores for clinical vignettes selected from ECCE at least six months after the intervention. To avoid test-retest effects, we will randomly select vignettes out of lot A and lot B, avoiding repetitions. In order to preserve the comparability of lots, we will select vignettes with similar, optimal psychometric characteristics.

10.
FASEB J ; 22(3): 741-51, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17928360

RESUMO

At present, approximately 150 different members of the adhesion-G protein-coupled receptor (GPCR) family have been identified in metazoans. Surprisingly, very little is known about their function, although they all possess large extracellular domains coupled to a seven-transmembrane domain, suggesting a potential role in cell adhesion and signaling. Here, we demonstrate how the human-restricted adhesion-GPCR, EMR2 (epidermal growth factor-like module-containing mucin-like hormone receptor), regulates neutrophil responses by potentiating the effects of a number of proinflammatory mediators and show that the transmembrane region is critical for adhesion-GPCR function. Using an anti-EMR2 antibody, ligation of EMR2 increases neutrophil adhesion and migration, and augments superoxide production and proteolytic enzyme degranulation. On neutrophil activation, EMR2 is rapidly translocated to membrane ruffles and the leading edge of the cell. Further supporting the role in neutrophil activation, EMR2 expression on circulating neutrophils is significantly increased in patients with systemic inflammation. These data illustrate a definitive function for a human adhesion-GPCR within the innate immune system and suggest an important role in potentiating the inflammatory response. Ligation of the adhesion-GPCR EMR2 regulates human neutrophil function.


Assuntos
Neutrófilos/fisiologia , Receptores Acoplados a Proteínas G/metabolismo , Animais , Linhagem Celular , Movimento Celular , Humanos , Camundongos , Ativação de Neutrófilo/imunologia , Superóxidos/metabolismo , Regulação para Cima
11.
J Immunol ; 179(6): 4110-24, 2007 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-17785850

RESUMO

Chloride ion efflux is an early event occurring after exposure of human neutrophils to several soluble agonists. Under these circumstances, a rapid and reversible fall in the high basal intracellular chloride (Cl-i) levels is observed. This event is thought to play a crucial role in the modulation of several critical neutrophil responses including activation and up-regulation of adhesion molecules, cell attachment and spreading, cytoplasmic alkalinization, and activation of the respiratory burst. At present, however, no data are available on chloride ion movements during neutrophil phagocytosis. In this study, we provide evidence that phagocytosis of Candida albicans opsonized with either whole serum, complement-derived opsonins, or purified human IgG elicits an early and long-lasting Cl- efflux accompanied by a marked, irreversible loss of Cl-i. Simultaneous assessment of Cl- efflux and phagocytosis in cytochalasin D-treated neutrophils indicated that Cl- efflux occurs without particle ingestion. These results suggest that engagement of immune receptors is sufficient to promote chloride ion movements. Several structurally unrelated chloride channel blockers inhibited phagocytosis-induced Cl- efflux as well as the release of azurophilic-but not specific-granules. It implicates that different neutrophil secretory compartments display distinct sensitivity to Cl-i modifications. Intriguingly, inhibitors of Cl- exchange inhibited cytosolic Ca2+ elevation, whereas Cl- efflux was not impaired in Ca2+-depleted neutrophils. We also show that FcgammaR(s)- and CR3/CR1-mediated Cl- efflux appears to be dependent on protein tyrosine phosphorylation but independent of PI3K and phospholipase C activation.


Assuntos
Degranulação Celular , Cloretos/química , Cloretos/metabolismo , Neutrófilos/química , Neutrófilos/metabolismo , Fagocitose , Vesículas Secretórias/química , Vesículas Secretórias/metabolismo , Transporte Biológico Ativo/imunologia , Cálcio/metabolismo , Cátions Bivalentes/metabolismo , Degranulação Celular/imunologia , Cloretos/agonistas , Cloretos/antagonistas & inibidores , Citoesqueleto/química , Citoesqueleto/metabolismo , Citosol/metabolismo , Humanos , Líquido Intracelular/química , Líquido Intracelular/metabolismo , Fagocitose/imunologia , Receptores Imunológicos/fisiologia , Transdução de Sinais/imunologia
13.
Eur J Immunol ; 36(8): 2159-69, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16838277

RESUMO

C-type lectins are the most diverse and prevalent lectin family in immunity. Particular interest has recently been attracted by the C-type lectin-like receptors on NK cells, which appear to regulate the activation/inhibitory balance of these cells, controlling cytotoxicity and cytokine production. We previously identified a human C-type lectin-like receptor, closely related to both the beta-glucan receptor and the lectin-like receptor for oxidized-LDL, named MICL (myeloid inhibitory C-type lectin-like receptor), which we had shown using chimeric analysis to function as an inhibitory receptor. Using a novel MICL-specific monoclonal antibody, we show here that human MICL is expressed primarily on myeloid cells, including granulocytes, monocytes, macrophages, and dendritic cells. Although MICL was highly N-glycosylated in primary cells, the level of glycosylation was found to vary between cell types. MICL surface expression was down-regulated during inflammatory/activation conditions in vitro, as well as during an in vivo model of acute inflammation, which we characterize here. This suggests that human MICL may be involved in the control of myeloid cell activation during inflammation.


Assuntos
Regulação para Baixo , Lectinas Tipo C/metabolismo , Receptores Mitogênicos/metabolismo , Animais , Anticorpos Monoclonais/imunologia , Células Cultivadas , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Glicosilação , Humanos , Inflamação/imunologia , Inflamação/metabolismo , Macrófagos/imunologia , Macrófagos/metabolismo , Camundongos
14.
Dermatology ; 213(1): 6-11, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16778419

RESUMO

BACKGROUND: Web-based systems are increasingly being considered for medical education. A draft legislation on distance-learning programs was licensed in Italy by the National Commission for Continuous Education in November 2003. A series of pilot studies were developed, among these the DermoFAD project, based on five simulated clinical cases of acne and a systematic appraisal of the evidence for their clinical management. From July 1 to August 27, 2004, a total of 500 medical doctors participated in a free of charge evaluation program of the project. OBSERVATIONS: Users were distributed all over Italy. Two hundred and eighty-one (56.2%) were primary care physicians, 83 (16.6%) dermatologists, and 136 (27.2%) other medical specialists. A wide range of connecting times was observed. The pass rate of each individual case, at first attempt, ranged from 44 to 77%. When asked to assess the overall distance-learning experience, 98% of the doctors considered it to be enjoyable. A total of 2,152 continuing medical education (CME) credits were awarded. Over 50% of the users stated they would still use the system if they had to pay for it. CONCLUSIONS: Our experience shows that distance learning is feasible and is well accepted by physicians. The DermoFAD program was an efficient means of delivering CME to the Italian medical community at large.


Assuntos
Dermatologia/educação , Internet , Estudos de Viabilidade , Itália
15.
J Leukoc Biol ; 79(1): 87-94, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16244110

RESUMO

Microbicidal activity of neutrophils is usually measured by colony-counting techniques after cell lysis in distilled water. While studying the effect of the reduced nicotinamide adenine dinucleotide phosphate-oxidase inhibitor diphenyleneiodonium (DPI) on the staphylocidal activity of neutrophils, we obtained inconsistent results: various degrees of inhibition in some experiments and no effect in others. The lysis step, i.e., dilution of neutrophils in distilled water, was the source of error. Cell-associated microorganisms were not dispersed effectively by this treatment. We overcame this problem by using water at pH 11 for cell lysis. Under these conditions, killing was inhibited completely and reproducibly by DPI. Here, we show that cell lysis in distilled water is incomplete and leads to an overestimate of microbial killing. This hinders identification of partial defects and makes complete defects appear as partial. We found that DPI-treated neutrophils and chronic granulomatous disease neutrophils were completely defective in killing of Staphylococcus aureus and Candida albicans and partially defective in killing of Escherichia coli after lysis with water pH 11, whereas after lysis in distilled water, killing of S. aureus and C. albicans was approximately 60% and approximately 70% of control killing, respectively, and killing of E. coli was normal. Likewise, killing of S. aureus by myeloperoxidase-deficient neutrophils was severely impaired after lysis in water pH 11 but appeared normal after lysis in distilled water. As most studies about neutrophil microbicidal activity have been performed using distilled water, our findings indicate that previous data about killing defects and the effects of agents that modulate microbicidal activity of neutrophils should be re-evaluated.


Assuntos
Bioensaio , Doença Granulomatosa Crônica , Neutrófilos/microbiologia , Fagocitose , Bioensaio/métodos , Candida albicans/crescimento & desenvolvimento , Células Cultivadas , Contagem de Colônia Microbiana , Inibidores Enzimáticos/farmacologia , Escherichia coli/crescimento & desenvolvimento , Doença Granulomatosa Crônica/enzimologia , Doença Granulomatosa Crônica/microbiologia , Doença Granulomatosa Crônica/patologia , Humanos , Concentração de Íons de Hidrogênio , Viabilidade Microbiana/imunologia , Neutrófilos/enzimologia , Neutrófilos/patologia , Oniocompostos/farmacologia , Peroxidase/antagonistas & inibidores , Peroxidase/deficiência , Peroxidase/metabolismo , Fagocitose/efeitos dos fármacos , Reprodutibilidade dos Testes , Staphylococcus aureus/crescimento & desenvolvimento
18.
BMC Health Serv Res ; 3(1): 24, 2003 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-14693035

RESUMO

BACKGROUND: Research has shown that many healthcare professionals have problems with guidelines as they would prefer to be given all relevant information relevant to decision-making rather than being told what they should do. This study assesses doctors' judgement of the validity, relevance, clarity and usability of the Italian translation of Clinical Evidence (CE) after its free distribution launched by the Italian Ministry of Health. METHODS: Opinions elicited using a standardised questionnaire delivered either by mail or during educational or professional meetings. RESULTS: Twenty percent (n = 1350) doctors participated the study. Most of them found CE's content valid, useful and relevant for their clinical practice, and said CE can foster communications among clinicians, particularly among GPs and specialists. Hospital doctors (63%) more often than GPs (48%) read the detailed presentation of individual chapters. Twenty-nine percent said CE brought changes in their clinical practice. Doctors appreciated CE's nature of an evidence-based information compendium and would have not preferred a collection of practice guidelines. CONCLUSIONS: Overall, the pilot initiative launched by the Italian Ministry of Health seems to have been well received and to support the subsequent decision to make the Italian edition of Clinical Evidence concise available to all doctors practising in the country. Local implementation initiatives should be warranted to favour doctor's use of CE.


Assuntos
Atitude do Pessoal de Saúde , Medicina Baseada em Evidências/normas , Médicos/psicologia , Guias de Prática Clínica como Assunto/normas , Obras Médicas de Referência , Medicina Baseada em Evidências/estatística & dados numéricos , Humanos , Disseminação de Informação , Itália , Corpo Clínico Hospitalar/psicologia , Médicos/classificação , Médicos de Família/psicologia , Projetos Piloto , Administração em Saúde Pública , Inquéritos e Questionários
19.
FEBS Lett ; 553(3): 360-4, 2003 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-14572651

RESUMO

We previously showed that a metalloprotease and a serine protease mediate shedding of the TNF-R75 (75-kDa tumor necrosis factor receptor) in neutrophils. Here we show that elastase is the TNF-R75 solubilizing serine protease. Release of the TNF-R75 by resting cells was almost totally inhibited by the serine protease inhibitor diisopropylfluorophosphate (DFP), by two synthetic, chemically unrelated, elastase-specific inhibitors and by alpha1-protease inhibitor. Release after TNF or FMLP (N-formyl-L-methionyl-L-leucyl-L-phenylalanine) stimulation was blocked by DFP and a metalloprotease inhibitor used in combination. Supernatants from resting neutrophils contained a 28-kDa fragment of the receptor, compatible with that generated by elastase, whose appearance was inhibited by DFP. Upon FMLP stimulation, the release of 28-kDa and 40-kDa fragments was observed, which was inhibited by DFP and a metalloprotease inhibitor, respectively. We conclude that elastase is the TNF-R75 sheddase of resting neutrophils and that it contributes to shedding of this receptor in stimulated cells.


Assuntos
Antígenos CD/metabolismo , Neutrófilos/enzimologia , Elastase Pancreática/metabolismo , Receptores do Fator de Necrose Tumoral/metabolismo , Animais , Antígenos CD/análise , Western Blotting , Humanos , Ácidos Hidroxâmicos/farmacologia , Isoflurofato/farmacologia , Metaloproteases/antagonistas & inibidores , Peso Molecular , N-Formilmetionina Leucil-Fenilalanina/antagonistas & inibidores , N-Formilmetionina Leucil-Fenilalanina/farmacologia , Neutrófilos/fisiologia , Elastase Pancreática/antagonistas & inibidores , Fragmentos de Peptídeos/antagonistas & inibidores , Fragmentos de Peptídeos/metabolismo , Testes de Precipitina , Inibidores de Proteases/farmacologia , Receptores do Fator de Necrose Tumoral/análise , Receptores do Fator de Necrose Tumoral/antagonistas & inibidores , Receptores Tipo II do Fator de Necrose Tumoral , Proteínas Recombinantes/antagonistas & inibidores , Proteínas Recombinantes/metabolismo , Suínos , Fator de Necrose Tumoral alfa/farmacologia
20.
J Leukoc Biol ; 72(4): 718-26, 2002 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-12377941

RESUMO

Polymorphonuclear leukocytes (PMN) respond to tumor necrosis factor (TNF) with a respiratory burst (RB) only after adherence to surfaces coated with extracellular matrix proteins such as fibronectin and fibrinogen (permissive substrates) but not with others such as laminin or collagen (nonpermissive substrates). As PMN adherence to both types of surfaces is dependent on beta(2) integrins, we investigated the molecular basis of the different metabolic response to TNF. In particular, we evaluated the relative role of each beta(2) integrin (alpha(L)beta(2), alpha(M)beta(2), and alpha(X)beta(2)) in adherence and O(2)(-) production of PMN residing on fibronectin- and laminin-coated surfaces, which were considered as models of permissive and nonpermissive surfaces, respectively. By using alpha chain-specific monoclonal antibodies (mAb), we show that alpha(M)beta(2) and alpha(X)beta(2) mediate adherence to fibronectin and laminin; alpha(L)beta(2) is not involved in adherence to laminin and has only a minimal contribution in adherence to fibronectin. Furthermore, production of O(2)(-) in response to TNF was induced by immobilized anti-alpha(L)beta(2) but not anti-alpha(M)beta(2) or anti-alpha(X)beta(2) mAb. A strong correlation was also found between expression of alpha(L)beta(2) and TNF-induced RB on fibronectin. Lastly, PMN responded to TNF on laminin with a RB after the inclusion of alpha(L)-specific mAb in the laminin coat. Thus, we conclude that TNF-induced RB by PMN residing on fibronectin is mediated by alpha(L)beta(2) and that alpha(M)beta(2) and alpha(X)beta(2) are likely to play an ancillary role to the signaling activity of alpha(L)beta(2) by facilitating its recruitment to sites of adherence. The nonpermissiveness of laminin appears to be a consequence of its inability to act as a ligand for alpha(L)beta(2).


Assuntos
Antígeno-1 Associado à Função Linfocitária/metabolismo , Neutrófilos/efeitos dos fármacos , Explosão Respiratória , Fator de Necrose Tumoral alfa/farmacologia , Adesão Celular , Células Cultivadas , Reagentes de Ligações Cruzadas , Citoesqueleto/metabolismo , Fibronectinas/metabolismo , Humanos , Integrina alfaXbeta2/metabolismo , Laminina/metabolismo , Antígeno de Macrófago 1/metabolismo , Neutrófilos/citologia , Neutrófilos/metabolismo , Superóxidos/metabolismo
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