RESUMEN
Consultants regularly need to decide whether a trainee can be entrusted to perform a clinical activity independently. 'Entrustable professional activities' (EPA) provide a framework for justifying and better utilising supervisor entrustment decisions for trainee feedback and assessment in the workplace. Since being proposed by Olle ten Cate in 2005, EPA are emerging as an integral part of many international medical curricula, and are being considered by the Royal Australasian College of Physicians in the current review of physician training. EPA are defined as tasks or responsibilities that can be entrusted to a trainee once sufficient competence is reached to allow for unsupervised practice. An example might be to entrust a trainee to 'Initiate and co-ordinate care of the palliative patient' with only off-site or indirect supervision. Rather than attempting to measure directly each of the many separate competencies required to undertake such a complex task, EPA direct the trainee and supervisor's attention to the trainee's performance in a limited number of selected, representative, important day-to-day activities. EPA-based assessment is gaining momentum, amongst significant concerns regarding feasibility of implementation. While the optimal process for designing and implementing EPA remains to be determined, it is an assessment strategy where the over-arching goal of optimal patient care remains in clear sight. This review explores the central role of trust in medical training, the case for EPA and potential barriers to implementing EPA-based assessment.
Asunto(s)
Competencia Clínica/normas , Educación Médica/normas , Médicos , Confianza , Rendimiento Laboral/educación , Educación Médica/métodos , HumanosRESUMEN
AIM: To review systematically the management of acute gout during hospitalization. METHODS: Case-file review of all episodes of acute gout occurring in a large tertiary hospital over a 20-month period. RESULTS: Of 134 acute gout episodes identified, the large majority (118) occurred in patients not admitted under the rheumatology unit. Baseline anti-gout medications were frequently ceased on admission and in 9% of episodes, no pharmacotherapy was prescribed. Delays in initiation of treatment occurred in up to 29% of patients. Acute management included anti-inflammatory monotherapy, or combinations of colchicine, non-steroidal anti-inflammatory drugs (NSAIDs) and corticosteroids. Of patients prescribed colchicine, 26% received >1.5 mg/day and a strong correlation was found between colchicine dose and the occurrence of diarrhoea. NSAIDs were prescribed in 29% of patients with pre-existing renal impairment. Overall, 25% of patients received inappropriate pharmacological management. In patients not under the direct care of the rheumatology unit, in-hospital rheumatology consultation was sought by the treating unit in 34% of episodes. Consultation was sought more frequently in patients with multiple joint involvement, but there were no other obvious differences in baseline clinical characteristics between cases with or without rheumatology involvement. In cases with rheumatology involvement, patients were investigated more frequently, they received more pharmacotherapeutic intervention, in particular combination anti-inflammatory therapy, and they achieved better symptomatic relief and long-term follow up. CONCLUSION: Acute gout episodes in hospital are variably investigated and treated with frequent suboptimal management. We recommend establishment of a hospital-wide protocol to support decision-making regarding investigations, treatment and follow up.
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Protocolos Clínicos , Gota/diagnóstico , Gota/terapia , Necesidades y Demandas de Servicios de Salud/tendencias , Hospitalización/tendencias , Enfermedad Aguda , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Protocolos Clínicos/normas , Manejo de la Enfermedad , Femenino , Estudios de Seguimiento , Supresores de la Gota/uso terapéutico , Necesidades y Demandas de Servicios de Salud/normas , Humanos , Masculino , Persona de Mediana Edad , Adulto JovenRESUMEN
It is now established that the subclasses of mast cells (MC) that reside in mucosal and serosal environments can be distinguished from one another in terms of their expression of specific secretory granule-localized proteases and proteoglycans. Further, the hematopoietic- and connective tissue-derived cytokines that regulate expression of the genes that encode these constituents of the granule can now be identified using recently developed gene-specific probes and recombinant cytokines. When bone marrow-derived MC (BMMC) were developed with recombinant interleukin 3 (rIL-3) and maintained with this cytokine in the absence or presence of recombinant c-kit ligand (rKL), they remained safranin-, produced almost no 35S-labeled heparin proteoglycans, and contained greater levels of mouse MC protease (MMCP) -5 mRNA and mast cell carboxypeptidase A (MC-CPA) mRNA than MMCP-6 mRNA. They did not contain MMCP-4 or -2 mRNA, genes expressed late in the differentiation of progenitor cells into serosal and mucosal MCs, respectively. In contrast, BMMC developed with rKL alone or by sequential culture in medium containing rIL-3 followed by rKL expressed high levels of MMCP-4 and -6 mRNA, as well as the transcripts that encode MMCP-5 and MC-CPA. Although rKL-developed BMMC were safranin+ and produced substantial amounts of 35S-labeled heparin proteoglycans, they contained only minimal amounts of histamine and MC-CPA enzymatic activity relative to serosal MC. These are the first studies to characterize the transcriptional granule phenotype of a population of BMMC derived using any recombinant cytokine, to demonstrate a dissociation between histochemical staining and granule maturation, and to demonstrate antagonistic regulation of late expressed protease genes by a cytokine.
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Factores de Crecimiento de Célula Hematopoyética/farmacología , Interleucina-3/farmacología , Mastocitos/enzimología , Serina Endopeptidasas/metabolismo , Animales , Células de la Médula Ósea , Diferenciación Celular/efectos de los fármacos , División Celular/efectos de los fármacos , Células Cultivadas , Gránulos Citoplasmáticos/enzimología , Expresión Génica , Heparina/análogos & derivados , Heparina/metabolismo , Técnicas In Vitro , Ratones , Proteoglicanos/metabolismo , ARN Mensajero/genética , Factor de Células MadreRESUMEN
OBJECTIVES: Elevated plasma C-reactive protein (CRP) levels predict coronary events, but it is unclear whether CRP plays a role in thrombosis associated with these events. We investigated tissue factor (TF) induction by CRP on peripheral blood mononuclear cells (PBMC) from patients with coronary disease. PATIENTS AND METHODS: PBMC from 35 patients with stable angina (SA) in study 1, 10 male patients with SA, 10 with unstable angina (UA) and 10 matched controls in study 2, and 25 patients with inflammatory disorders (ID) and 24 normal controls in study 3 were stimulated with CRP, interferon-gamma (IFN) or lipopolysaccharide (LPS), or their combination. PBMC from additional normal donors were also stimulated with CRP in adherent and non-adherent conditions, and TF activity, antigen and mRNA expression detected. RESULTS: CRP (5-25 microg mL(-1)) dose dependently induced more TF on PBMC from SA patients than 42 contemporary controls (P = 0.001, study 1). Compared with controls, patients with SA or UA had higher basal, and much higher CRP- or CRP/LPS-induced monocyte TF activity although serum CRP levels were similar (study 2). IFN induced monocyte TF activity in patients with angina, but not in controls. Basal or CRP-induced TF levels did not differ between controls and ID, even though ID patients had much higher serum CRP levels (study 3). CRP-induced monocyte TF activity correlated with serum CRP levels in controls (P = 0.005) and ID (P = 0.007) in study 3, but not in patients with angina (P =0.84) in study 2. CRP induced more TF activity, protein and mRNA under adherent than non-adherent conditions implying that it may mainly target macrophages in lymphocyte-rich lesions. CONCLUSIONS: Our results indicate that monocytes from patients with angina are preactivated and express TF but CRP is unlikely to be a major priming factor in vivo. IFN and CRP further increase TF levels that may contribute to the hypercoagulable state in coronary disease.
Asunto(s)
Proteína C-Reactiva/farmacología , Enfermedad de la Arteria Coronaria/sangre , Trombofilia/inducido químicamente , Adulto , Anciano , Angina de Pecho/sangre , Estudios de Casos y Controles , Células Cultivadas , Relación Dosis-Respuesta a Droga , Femenino , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , Interferón gamma/farmacología , Leucocitos Mononucleares/efectos de los fármacos , Leucocitos Mononucleares/patología , Lipopolisacáridos/farmacología , Masculino , Persona de Mediana Edad , Tromboplastina/genéticaRESUMEN
Having reviewed the literature on the association of aPL antibodies with clinical manifestations, it is clear that this group of autoantibodies are of considerable importance. The presence of aPL antibodies in some but not all individuals confers a risk of a clinical syndrome characterized by recurrent arterial or venous thrombosis, thrombocytopenia, hemolytic anemia, or positive Coombs' test, and in females, recurrent idiopathic fetal loss. In SLE, the risk is approximately 40%, compared with a risk of 15% in the absence of aPL antibodies. However, only one half of persons possessing these antibodies have SLE, and overall the risk is around 30%. In some circumstances, such as in chlorpromazine or infection-associated aPL antibodies, there appears to be no increased risk. At the other end of the spectrum are seen patients whose only clinical manifestations comprise features of this clinical syndrome, and this entity has been designated the primary antiphospholipid syndrome (PAPS). aPL antibodies are also important because they are not uncommon. They have been found frequently in women with idiopathic recurrent fetal loss (30%), in non-autoimmune patients with ischemic heart disease (20%), or venous thrombosis (up to 30%), or stroke (4-47%), and in chronic immune thrombocytopenia (30%). These autoantibodies can be detected using sensitive solid-phase immunoassays employing the CL antigen, or in appropriate coagulation tests to detect LA activity. These assays are simple to perform but require care in selection of the best test and in interpretation of results. Current tests do not distinguish between those persons at risk of the clinical events and those not at risk. Detection of specific isotypes (especially IgG) and antibody level may aid in such a designation. Treatment of aPL antibody-associated syndromes remains a controversial subject. Since thromboses are associated with significant morbidity and potential mortality, there is a good argument for long-term preventive antithrombotic therapy, at least for as long as the antibodies are detectable, in those patients in whom clinical complications have previously occurred. It is not generally recommended that this treatment be offered to individuals in whom aPL antibodies are detected but who have not suffered previous thromboses, since the risk of such events does not appear to be equal within a group of aPL antibody-positive persons. This particularly applies to pregnant women, since live births and uncomplicated pregnancies are observed regularly in the presence of aPL antibodies without specific treatment. A previous history of at least one unexplained, late fetal loss is considered a prerequisite before intervention in subsequent pregnancies.(ABSTRACT TRUNCATED AT 400 WORDS)
Asunto(s)
Autoanticuerpos/inmunología , Enfermedades Autoinmunes/inmunología , Fosfolípidos/inmunología , Anemia Hemolítica/etiología , Plaquetas/inmunología , Cardiolipinas/inmunología , Humanos , Infecciones/inmunología , Fosfatidiletanolaminas/inmunología , Trombocitopenia/etiología , Trombosis/etiologíaRESUMEN
Thrombospondin 1 (TSP1) is a multidomain glycoprotein from platelets and cells which functions in cell-cell and cell-matrix interactions. The structure of TSP1 is regulated by sulfhydryl-disulfide interchange in the carboxy-terminal Ca2(+)-binding loops and globular domain which markedly influence its interaction with cell surface integrins and its inhibition of neutrophil enzymes. We have identified murine monoclonal antibodies that recognized different disulfide-bonded forms of TSP1, made by preparing TSP1 in buffers containing either 0.1 mM or 2 mM Ca2+. Antibody HB8432 recognizes TSP1 prepared in buffers containing either 0.1 or 2 mM Ca2+, while antibodies D4.6 and A65M recognized only TSP1 prepared in buffers containing 0.1 mM Ca2+. The antibodies recognize these different TSP1 preparations either adsorbed to plastic or extracellular matrix. Immunohistochemistry of human rheumatoid synovial tissue using HB8432 resulted in staining of numerous blood vessel walls and matrix cells, while D4.6 and A65M stained a subset of the HB8432 positive blood vessels and only occasionally stained matrix cells. These results suggested that different disulfide-bonded forms of TSP1 were being expressed in different areas of inflamed tissue.
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Anticuerpos Monoclonales/inmunología , Cistina/química , Epítopos/inmunología , Glicoproteínas de Membrana/inmunología , Adsorción , Animales , Especificidad de Anticuerpos , Reacciones Antígeno-Anticuerpo , Artritis Reumatoide/inmunología , Artritis Reumatoide/metabolismo , Colágeno , Combinación de Medicamentos , Epítopos/química , Humanos , Laminina , Glicoproteínas de Membrana/análisis , Glicoproteínas de Membrana/química , Ratones , Plásticos , Unión Proteica , Estructura Terciaria de Proteína , Proteoglicanos , Conejos , Membrana Sinovial/química , TrombospondinasRESUMEN
Antiphospholipid antibodies have been found to be strongly associated with syndromes characterised by spontaneous arterial and venous thromboses, recurrent miscarriage, immune thrombocytopenia, and occasionally neurological manifestations. These antibodies can be detected using solid phase immunoassays, and by their effect on prolonging phospholipid dependent clotting tests. This latter phenomenon is termed the lupus anticoagulant (LA). The relationship between anticardiolipin antibodies (ACA) and the LA activity of plasma was investigated in 14 patients. Plasma of these patients exhibited both LA activity and high levels of ACA. The patients included 7 with systemic lupus erythematosus, 6 without and 1 chlorpromazine induced lupus anticoagulant. 7 patients had a history of thrombosis and 7 did not, despite high antibody levels. Plasma was incubated in a serial fashion with solid phase cardiolipin and the residual ACA level and LA activity were monitored using a solid phase enzyme linked immunoassay, and the kaolin clotting time (KCT) and activated partial thromboplastin time (APTT) respectively. There was no correlation between baseline ACA levels and parameters of LA activity (dKCT or dAPTT) in contrast to previous reports. However, there was a concurrent reduction in both LA and ACA levels over 24 hours during incubation with cardiolipin in all patients. The rate of reduction of both parameters was highly correlated (r = 0.99. p less than 0.001). The relative reduction of LA activity versus ACA level varied between patients, and may represent different affinities for phospholipid in thromboplastin versus phospholipid in solid phase. Thus, despite the lack of concordance between LA and ACA in many patients, the two activities can be removed concurrently in vitro, suggesting similar binding specificities of the antibodies. The incomplete concordance could be explained by varying affinities for different structural presentations of the lipid antigen.
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Factores de Coagulación Sanguínea/inmunología , Cardiolipinas/inmunología , Lupus Eritematoso Sistémico/inmunología , Trombosis/inmunología , Adulto , Anciano , Especificidad de Anticuerpos , Pruebas de Coagulación Sanguínea , Ensayo de Inmunoadsorción Enzimática , Humanos , Inhibidor de Coagulación del Lupus , Persona de Mediana Edad , Fosfolípidos/metabolismoRESUMEN
INTRODUCTION: This study aimed to determine outcomes of percutaneous vertebroplasty for osteoporotic vertebral compression fractures (VCFs). METHODS: Prospective assessment of short-term (Asunto(s)
Fracturas por Compresión/cirugía
, Osteoporosis/complicaciones
, Fracturas de la Columna Vertebral/cirugía
, Vertebroplastia/métodos
, Anciano
, Anciano de 80 o más Años
, Dolor de Espalda/diagnóstico
, Dolor de Espalda/etiología
, Dolor de Espalda/cirugía
, Evaluación de la Discapacidad
, Femenino
, Estudios de Seguimiento
, Fracturas por Compresión/etiología
, Humanos
, Masculino
, Persona de Mediana Edad
, Dimensión del Dolor/métodos
, Dimensión del Dolor/estadística & datos numéricos
, Estudios Prospectivos
, Radiología Intervencionista/métodos
, Fracturas de la Columna Vertebral/etiología
, Columna Vertebral/cirugía
, Resultado del Tratamiento
Asunto(s)
Anticuerpos/aislamiento & purificación , Fosfolípidos/inmunología , Factores de Coagulación Sanguínea/inmunología , Factores de Coagulación Sanguínea/metabolismo , Proteínas Sanguíneas/análisis , Colesterol , Cromatografía de Afinidad , Cromatografía por Intercambio Iónico , Electroforesis en Gel de Poliacrilamida , Ensayo de Inmunoadsorción Enzimática , Humanos , Inmunoglobulinas/análisis , Inhibidor de Coagulación del Lupus , Fosfatidilserinas , Fosfolípidos/metabolismoAsunto(s)
Anticuerpos/fisiología , Cardiolipinas/inmunología , Anticuerpos/análisis , Antígenos/inmunología , Autoanticuerpos/inmunología , Factores de Coagulación Sanguínea/inmunología , Factores de Coagulación Sanguínea/fisiología , Glicoproteínas/inmunología , Humanos , Inhibidor de Coagulación del Lupus , Fosfolípidos/inmunología , Reaginas/inmunología , beta 2 Glicoproteína IRESUMEN
OBJECTIVES: To compare the expression of leucocyte immunoglobulin-like receptors (LILRs) also known as ILTs and LIRs in rheumatoid arthritis (RA) synovial membrane before and after treatment with disease-modifying anti-rheumatic drugs (DMARDs) and investigate regulation of LILR-expression and function in vitro. METHODS: A study was performed on serial synovial biopsies obtained from 10 RA patients before and after treatment with DMARDs. Expression of the activating LILRA2 (ILT1 or LIR-7) and inhibitory LILRB2 (ILT4 or LIR-2) and LILRB3 (ILT5 or LIR-3) was evaluated by immunohistochemical staining, and quantified by a validated scoring system. Peripheral blood mononuclear cells and in vitro derived macrophages were used to determine effects of DMARDs on expression and function of LILRs. RESULTS: Abundant expression of LILRB2, B3 and A2 was found in synovial tissue of all patients before treatment. Number of inflammatory cells expressing both inhibitory and activating LILRs dramatically decreased in patients who responded to treatment, but remained high in those who did not. However, treatment of macrophages with DMARDs in vitro did not down-regulate LILR expression. On the other hand, reduction in LILR expression in RA synovia was associated with decreased inflammatory infiltrates in those who responded to treatment. Cross-linking of LILRA2 on macrophages caused substantial production of tumour necrosis factor (TNF-alpha) in a dose- and time-dependent manner that was strongly inhibited by dexamethasone. CONCLUSIONS: We show that expression of LILRs in RA synovium was significantly reduced only in patients who responded to treatment. However, clinical responses may not be due to direct effects of DMARDs on LILR expression but due to partial inhibition of LIRA2-mediated TNF-alpha production by steroids leading to suppression of inflammation.
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Antirreumáticos/uso terapéutico , Artritis Reumatoide/inmunología , Regulación hacia Abajo/efectos de los fármacos , Glicoproteínas de Membrana/metabolismo , Receptores Inmunológicos/metabolismo , Membrana Sinovial/inmunología , Anciano , Anciano de 80 o más Años , Antirreumáticos/farmacología , Artritis Reumatoide/tratamiento farmacológico , Células Cultivadas , Estudios de Cohortes , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Activación de Macrófagos , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Masculino , Persona de Mediana Edad , Receptores Fc/metabolismo , Índice de Severidad de la EnfermedadRESUMEN
This review has focused on some recent developments which have begun to define the immunologic specificity of aPL antibodies. These studies have revealed that these immunoglobulins are more complex than has been realised to date and, more importantly, they offer new approaches to investigate how the prothrombotic diathesis associated with aPL antibodies might arise.
Asunto(s)
Autoanticuerpos , Fosfolípidos/inmunología , Síndrome Antifosfolípido/inmunología , Síndrome Antifosfolípido/terapia , Autoanticuerpos/análisis , Autoanticuerpos/inmunología , Humanos , Lupus Eritematoso Sistémico/inmunologíaRESUMEN
OBJECTIVE: To determine the distribution of mast cell subsets and their density in synovium from normal subjects and from patients with osteoarthritis (OA) and rheumatoid arthritis (RA): METHODS: A sequential double-immunohistochemical staining technique was used to distinguish mast cells as positive for tryptase only (MCT) or for tryptase plus chymase (MCTC). Synovial tissue was obtained from RA patients (n = 16), OA patients (n = 18), and normal subjects (n = 15). Sections were analyzed to a depth of 1 mm from the synoviocyte lining layer by quantitative histomorphometry. Immunohistochemical data were correlated with histologic findings and clinical indices of disease activity. RESULTS: In normal synovium, the majority of mast cells belonged to the MCTC subset, outnumbering MCT cells by 5:1. The mean density of mast cells was significantly increased in RA synovia (60.9 cells/mm2) compared with OA (21.7 cells/mm2) and with normal (9.4 cells/mm2) synovia. Selective expansion of the MCT subset accounted for the increased mast cell density in OA. In RA, both subsets expanded and were associated with infiltrating inflammatory cells or with regions of highly cellular fibrous tissue (mainly MCTC). An association was noted between clinical parameters of activity or progression of rheumatoid disease and the density of MCTC cells, especially the density in the superficial layer of synovium. In RA synovia, we found no evidence of the chymase only, or MCC, immunophenotype. CONCLUSION: MCTC mast cells expand in RA but not OA, associate with regions of "active" fibrosis, and correlate with parameters of disease activity or progression of RA. These findings implicate the MCTC subset of mast cells in the pathologic mechanisms that mediate tissue damage in RA.
Asunto(s)
Artritis Reumatoide/patología , Mastocitos/fisiología , Membrana Sinovial/patología , Artritis Reumatoide/genética , Recuento de Células , Quimasas , Humanos , Inmunofenotipificación , Mastocitos/clasificación , Mastocitos/enzimología , Osteoartritis/genética , Osteoartritis/patología , Fenotipo , Serina Endopeptidasas/análisis , Coloración y EtiquetadoRESUMEN
That mast cells participate in inflammatory reactions is beyond argument. A major question posed by mast cell biologists is whether specific functions in inflammation are subserved by different subsets of the mast cell population. We have investigated the two major subsets of human mast cells (MC(T) and MC(TC)), in the chronic inflammatory processes associated with rheumatoid arthritis (RA). Whereas normal synovium contains mainly MC(TC) mast cells, the MC(T) subset is selectively expanded in early RA, in numbers that correlate with synoviocyte hyperplasia and T-lymphocyte infiltration. In contrast, in RA of long duration, MC(TC) mast cells predominate in numbers that correlate with clinical indices of rapidity of disease progression. We suggest that MC(T) mast cells participate in active inflammatory events, whereas MC(TC) mast cells may be more relevant in repair or damage to connective tissues.
Asunto(s)
Inflamación , Mastocitos/clasificación , Mastocitos/fisiología , Artritis Reumatoide/inmunología , Artritis Reumatoide/patología , Humanos , Inflamación/inmunología , Inflamación/patología , Mastocitos/inmunología , Membrana Sinovial/inmunología , Membrana Sinovial/patologíaRESUMEN
Patients with antiphospholipid syndrome (APS) suffer recurrent thromboses, thrombocytopenia, and/or fetal loss in association with Abs that can be detected in phospholipid-dependent assays. Despite the name, the Igs associated with APS are predominantly directed against epitopes on phospholipid-binding plasma proteins, such as beta 2-glycoprotein-1 (beta 2GP1) and prothrombin. The aim of this study was to examine the cellular immune response to beta 2GP1 in patients with APS. Using a serum-free stimulation assay, PBMCs from 8 of 18 patients with APS proliferated to purified beta 2GP1 or to the beta 2GP1 present in serum, whereas no stimulation was observed by PBMCs from healthy individuals, patients with other autoimmune diseases, or anticardiolipin Ab-positive patients without histories of thromboses or fetal loss. The immune response was Ag-specific, requiring class II molecules, CD4+ T cells, and APCs, and was associated with a selective expansion of CD4+ but not CD8+ T cells. The proliferating T cells produced IFN-gamma but not IL-4, indicating a bias toward a type 1 immune response. Chronic low grade stimulation of autoreactive beta 2GP1-specific, IFN-gamma-producing Th1 CD4+ T cells may contribute to the high risk of thromboses and pregnancy failure in patients with APS.
Asunto(s)
Síndrome Antifosfolípido/inmunología , Glicoproteínas/inmunología , Adulto , Anticuerpos Antifosfolípidos/sangre , Anticoagulantes/sangre , Anticoagulantes/inmunología , Células Presentadoras de Antígenos/inmunología , Síndrome Antifosfolípido/sangre , Linfocitos T CD4-Positivos/inmunología , Epítopos de Linfocito T/inmunología , Glicoproteínas/sangre , Glicoproteínas/aislamiento & purificación , Humanos , Inmunidad Celular , Interferón gamma/biosíntesis , Interferón gamma/sangre , Interleucina-4/biosíntesis , Interleucina-4/sangre , Leucocitos Mononucleares/inmunología , Leucocitos Mononucleares/metabolismo , Activación de Linfocitos , Persona de Mediana Edad , Fosfolípidos/sangre , Fosfolípidos/inmunología , beta 2 Glicoproteína IRESUMEN
Autoantibodies to phospholipid antigens can be characterized using solid phase immunoassays to detect anticardiolipin antibodies (ACA) or in phospholipid-dependent clotting tests where lupus anticoagulant (LA) activity can be demonstrated. It has not been established whether each activity is due to the same or separate antibody subgroups. Plasma from two patients with high levels of both activities were used for purification of ACA and LA using sequential ion-exchange, gel-filtration, and anti-Ig affinity chromatography. Plasma could be separated into fractions containing each activity in the absence of the other. In these fractions, antibodies responsible for LA activity do not bind to isolated phospholipids in solid phase immunoassays, and conversely antibodies binding in these assays (ACA) do not possess LA activity, suggesting LA are directed against a more complex lipid epitope. In addition, in one patient ACA was of IgG isotype only, whilst LA was due to IgG and IgM isotypes. In this patient, the IgG-ACA was heterogeneous with three peaks clearly separated on ion-exchange chromatography. Affinity purified antiphospholipid antibodies have been previously prepared from a number of patients using a phosphatidyl-serine column and antibodies purified in this manner possess ACA but not LA activity. Taken together, these data indicate that tests for ACA and LA define separable subgroups of phospholipid binding antibodies, thus explaining the discordance often seen between the two activities.
Asunto(s)
Autoanticuerpos/aislamiento & purificación , Factores de Coagulación Sanguínea/inmunología , Cardiolipinas/inmunología , Fosfolípidos/inmunología , Adulto , Factores de Coagulación Sanguínea/aislamiento & purificación , Cromatografía de Afinidad , Cromatografía en Gel , Cromatografía por Intercambio Iónico , Electroforesis en Gel de Poliacrilamida , Femenino , Humanos , Inmunoglobulina G/aislamiento & purificación , Inmunoglobulina M/aislamiento & purificación , Inhibidor de Coagulación del Lupus , Masculino , Trombosis/inmunologíaRESUMEN
Rheumatoid arthritis (RA) affects approximately 1% of the population and is a chronic inflammatory joint disease resulting in joint destruction, increased morbidity and mortality. Although the aetiology of this disease is unknown, the pivotal role played by cytokines and degradative enzymes in mediating inflammation and joint destruction, particularly early in the disease process, has been the focus of recent literature and will be the focus of this review. Up until recently, studies on early RA were limited as there was an inherent delay in patients reaching the rheumatologist's care and initial diagnostic confusion may have compounded these problems. In particular, the observation that early intervention improves outcome, has driven the study of early RA. It is difficult to define early RA but most studies have defined this as disease duration of less than 12 months from symptom onset. Clearly, it is important to study the synovial membrane in early disease, in particular to try and answer the important questions: (1) What are the earliest changes to occur in the RA synovium? (2) Can we distinguish RA on the basis of synovial membrane pathology? (3) Can synovial immunopathology predict outcome? (4) What is the role of arthroscopic biopsy in early RA?
Asunto(s)
Artritis Reumatoide/fisiopatología , Mediadores de Inflamación/fisiología , Membrana Sinovial/fisiopatología , Artritis Reumatoide/diagnóstico , Artritis Reumatoide/metabolismo , Artritis Reumatoide/patología , Artroscopía , Biopsia , Moléculas de Adhesión Celular , Quimiocinas/metabolismo , Quimiocinas/fisiología , Citocinas/metabolismo , Citocinas/fisiología , Humanos , Membrana Sinovial/metabolismo , Membrana Sinovial/patologíaRESUMEN
OBJECTIVE: Thrombospondin 1 (TSP1) is a potent active site inhibitor of leukocyte elastase and cathepsin G. This effect is markedly dependent on the disulfide-bond conformation of TSP1, with one isoform, TSP1(0.1), being the most potent. The aims of this study were to examine the expression of different disulfide-bonded isoforms of TSP1 in inflammatory environments in which elastase and cathepsin G are present in variable amounts, and to determine the relationship between these proteinases and their potential inhibitor. METHODS: Immunohistochemical staining and histomorphometric analysis were used to examine adjacent sections of synovial tissue from patients with rheumatoid arthritis (RA), osteoarthritis (OA), and meniscal trauma (MT), for expression of TSP1 and the TSP1(0.1) isoform, elastase, cathepsin G, and chymase. RESULTS: TSP1 localized to vessels and cells within the synovium. TSP1 expression was highly up-regulated in RA (mean density 98 cells and vessels/mm2, compared with 13/mm2 in OA and 17/mm2 in MT). The TSP1(0.1) isoform was found virtually exclusively in RA, with 44% of vascular TSP1 staining being due to the TSP1(0.1) isoform in RA, as compared with 7% in OA (P = 0.0047). Elastase- and cathepsin G-positive cells were abundant in RA, with mean densities of 106 cells/mm2 and 103 cells/mm2, respectively, compared with 2 cells/mm2 and 11 cells/mm2 in OA. There was a wide range of both TSP1 and proteinase expression within the RA group, but samples containing large numbers of elastase- and cathepsin G-positive cells also showed high expression of TSP1, especially TSP1(0.1). A strong correlation was found between elastase or cathepsin G densities and TSP1(0.1) expression in blood vessels (r = 0.86 and r = 0.76 respectively, P < 0.01). CONCLUSION: TSP1(0.1), with the most potent inhibitory activity in vitro, is specifically up-regulated in RA, and this up-regulation is in proportion to the numbers of surrounding leukocytes containing elastase and cathepsin G. One role of TSP1 may be to act as a matrix-based regulator of leukocyte-derived serine proteinases in vivo.