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1.
J Thromb Haemost ; 5(11): 2204-10, 2007 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17958739

RESUMO

BACKGROUND: Several studies suggest that antiphospholipid antibodies interfere with the activity of activated protein C (APC). This acquired form of APC resistance has been proposed as a possible pathogenic mechanism underlying hypercoagulability associated with the antiphospholipid syndrome (APS). OBJECTIVES: We wanted to investigate the inhibitory effect of recombinant APC (rAPC) on ex vivo thrombin generation in plasma and the modification of this effect by the presence of lupus anticoagulants (LA). PATIENTS/METHODS: We analyzed plasmas from 81 patients with LA (52 patients fulfilling the criteria for the APS) and 91 controls. Percent inhibition of the endogenous thrombin potential (ETP) as a parameter of APC sensitivity was determined in plasmas using a thrombin generation-based APC resistance test probed with rAPC. All results were normalized using pooled normal plasma (PNP) as a reference. RESULTS: Normalized percent inhibition of ETP by APC was lower in patients with LA [61.4%, 95% confidence interval (CI) 45.8-74.5%] compared to controls (107.8%, 95% CI: 107.1-109.3%). In patients with LA and APS, median inhibition was lower than in patients with LA without APS (44.6%, 95% CI: 30.1-55.7% vs. 78.8%, 95% CI: 73.9-95.8%). This difference also persisted when patients on warfarin therapy were excluded from the APS subgroup. CONCLUSIONS: APC resistance can be demonstrated with a thrombin generation-based test in a majority of patients with the LA laboratory phenotype. A history of thrombotic events in patients with LA is associated with a stronger resistance to the anticoagulant effect of APC.


Assuntos
Resistência à Proteína C Ativada/complicações , Síndrome Antifosfolipídica/complicações , Inibidor de Coagulação do Lúpus/sangue , Trombina/farmacologia , Trombose/etiologia , Adulto , Testes de Coagulação Sanguínea , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Proteína C/farmacologia , Proteínas Recombinantes , Trombofilia/complicações , Varfarina/farmacologia , Varfarina/uso terapêutico
2.
Eur J Cancer ; 43(11): 1670-8, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17574838

RESUMO

AIM: To test the reliability, validity and sensitivity of the European Organisation for Research and Treatment of Cancer (EORTC) QLQ-MY24 questionnaire, designed to assess the quality of life of myeloma patients with the QLQ-C30. METHODS: The study was carried out through the EORTC Quality of Life Group using clinical trials in seven countries. All trials used the QLQ-C30 and QLQ-MY24 at baseline and a follow-up timepoint. RESULTS: Two hundred and forty patients participated. The questionnaires were acceptable to patients. The hypothesised scale structure (disease symptoms, side-effects, body image and future perspective) was confirmed by multi-trait scaling, internal consistency and correlation analysis. Most scales demonstrated sensitivity to change and discriminated between clinically different patients. The social support scale (4 items) was removed due to observed ceiling effects. CONCLUSION: The final questionnaire contains 20 items, QLQ-MY20, and is a reliable and valid instrument recommended for use with the QLQ-C30 in myeloma patients.


Assuntos
Mieloma Múltiplo/psicologia , Qualidade de Vida , Inquéritos e Questionários/normas , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Cooperação do Paciente , Estudos Prospectivos , Sensibilidade e Especificidade
3.
J Thromb Haemost ; 3(5): 848-53, 2005 May.
Artigo em Inglês | MEDLINE | ID: mdl-15869575

RESUMO

BACKGROUND: The optimal intensity of oral anticoagulation for the prevention of recurrent thrombosis in patients with antiphospholipid antibody syndrome is uncertain. Retrospective studies show that only high-intensity oral anticoagulation [target international normalized ratio (INR) >3.0] is effective but a recent randomized clinical trial comparing high (INR range 3.0-4.0) vs. moderate (INR 2.0-3.0) intensities of anticoagulation failed to confirm this assumption. METHODS: We conducted a randomized trial in which 109 patients with antiphospholipid syndrome (APS) and previous thrombosis were given either high-intensity warfarin (INR range 3.0-4.5, 54 patients) or standard antithrombotic therapy (warfarin, INR range 2.0-3.0 in 52 patients or aspirin alone, 100 mg day(-1) in three patients) to determine whether intensive anticoagulation is superior to standard treatment in preventing symptomatic thromboembolism without increasing the bleeding risk. RESULTS: The 109 patients enrolled in the trial were followed up for a median time of 3.6 years. Mean INR during follow-up was 3.2 (SD 0.6) in the high-intensity warfarin group and 2.5 (SD 0.3) (P < 0.0001) in the conventional treatment patients given warfarin. Recurrent thrombosis was observed in six of 54 patients (11.1%) assigned to receive high-intensity warfarin and in three of 55 patients (5.5%) assigned to receive conventional treatment [hazard ratio for the high intensity group, 1.97; 95% confidence interval (CI) 0.49-7.89]. Major and minor bleeding occurred in 15 patients (two major) (27.8%) assigned to receive high-intensity warfarin and eight (three major) (14.6%) assigned to receive conventional treatment (hazard ratio 2.18; 95% CI 0.92-5.15). CONCLUSIONS: High-intensity warfarin was not superior to standard treatment in preventing recurrent thrombosis in patients with APS and was associated with an increased rate of minor hemorrhagic complications.


Assuntos
Síndrome Antifosfolipídica/tratamento farmacológico , Fibrinolíticos/farmacologia , Trombose/patologia , Trombose/prevenção & controle , Varfarina/uso terapêutico , Administração Oral , Adulto , Algoritmos , Anticorpos Anticardiolipina/química , Anticoagulantes/uso terapêutico , Aspirina/uso terapêutico , Ensaios Clínicos como Assunto , Feminino , Humanos , Coeficiente Internacional Normatizado , Masculino , Pessoa de Meia-Idade , Razão de Chances , Recidiva , Risco , Estatística como Assunto , Tromboembolia/tratamento farmacológico , Fatores de Tempo , Resultado do Tratamento
4.
Thromb Haemost ; 83(5): 704-8, 2000 May.
Artigo em Inglês | MEDLINE | ID: mdl-10823266

RESUMO

The Lupus Ratio (LR) test for lupus anticoagulants integrates screening, mixing with normal plasma and confirmation procedures into one assay. The sensitivity and reproducibility of the APTT based version of this assay was tested in an interlaboratory study that was part of the Fifth International Survey of Lupus Anticoagulants (ISLA-5). One LA negative plasma containing heparin, six LA positive plasmas and a normal pooled plasma (NP) were distributed to 31 laboratories world-wide together with two APTT reagents, one with a high and one with a low phospholipid concentration. The laboratories performed two APTTs, one with each reagent, on 1:1 mixtures of test plasma and NP. The ratio between the two clotting times was divided by the corresponding ratio for the NP. This final ratio is the LR of that plasma. The overall sensitivity was found to be 95.1%, and the normal, heparin-containing sample was reported to be negative by all the laboratories. When the results were grouped in low, medium and high positive plasmas, a "consensus" regarding the strength of each plasma was easily found. 85.0% of the results were in agreement with this consensus. This study shows that with the LR test, it is possible to obtain high interlaboratory agreement regarding the presence or absence of LA as well as the semi-quantification of this inhibitor.


Assuntos
Inibidor de Coagulação do Lúpus/sangue , Tempo de Tromboplastina Parcial , Anticoagulantes/farmacologia , Heparina/farmacologia , Humanos , Indicadores e Reagentes , Variações Dependentes do Observador , Fosfolipídeos/sangue , Valores de Referência , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
5.
Bone Marrow Transplant ; 17(4): 577-81, 1996 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-8722358

RESUMO

Evidence of activation of coagulation was sought in serial plasma samples from 25 ABMT candidates with malignant lymphoma admitted for bone marrow harvesting: 10 females and 15 males, median age 41 years (range 27-58 years). Nineteen patients had non-Hodgkin's lymphoma (NHL) and six had Hodgkin's disease. Of those with NHL, 14 had high-grade and five low- grade disease. The plasma levels of markers of activation (prothrombin fragment 1 + 2, thrombin-antithrombin complexes, fibrinopeptide A and fibrinmonomers) increased significantly (P < 0.001) in association with harvesting. Except for fibrinopeptide A, the indicators of activation were still significantly elevated 24 h after marrow aspiration. Beta-thromboglobulin, a marker of the platelet release reaction, also increased significantly (P < 0.01). Four out of nine patients in whom a long-term central venous catheter was inserted just after marrow aspiration, developed catheter-related deep vein thrombosis, verified venographically, shortly after harvesting. These results suggest that patient with malignant lymphoma undergoing marrow harvesting develop a hypercoagulable state, and that insertion of a central intravenous catheter immediately after marrow harvesting should be avoided to prevent the development of symptomatic deep vein thrombosis.


Assuntos
Coagulação Sanguínea , Transplante de Medula Óssea , Cateterismo Venoso Central/efeitos adversos , Ílio/lesões , Linfoma/sangue , Esterno/lesões , Tromboflebite/etiologia , Transplante Autólogo , Ferimentos e Lesões/sangue , Adulto , Anticoagulantes/farmacologia , Anticoagulantes/uso terapêutico , Antitrombina III/análise , Biomarcadores/sangue , Coagulação Sanguínea/efeitos dos fármacos , Ritmo Circadiano , Feminino , Fibrina/análise , Fibrinólise/efeitos dos fármacos , Fibrinopeptídeo A/análise , Heparina/farmacologia , Heparina/uso terapêutico , Doença de Hodgkin/classificação , Doença de Hodgkin/complicações , Doença de Hodgkin/terapia , Humanos , Linfoma/complicações , Linfoma/terapia , Linfoma não Hodgkin/classificação , Linfoma não Hodgkin/complicações , Linfoma não Hodgkin/terapia , Masculino , Pessoa de Meia-Idade , Fragmentos de Peptídeos/análise , Peptídeo Hidrolases/análise , Inibidor 1 de Ativador de Plasminogênio/análise , Contagem de Plaquetas , Pré-Medicação , Protrombina/análise , Veia Subclávia , beta-Tromboglobulina/análise
6.
Am J Clin Pathol ; 103(1): 108-11, 1995 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-7817935

RESUMO

The authors have evaluated two commercial assays for lupus anticoagulants (LA), the DVVtest+DVV confirm (American Diagnostica, Greenwich, CT) and the PTT-LA+Staclot LA (Diagnostica Stago, Asnieres-Sur-Seine, France). The assays were compared with a previously described quantitative, semi-automated, and computer-assisted test, which is based on two assays, using the activated partial thromboplastin time (APTT) and the Russell's viper venom time (RVVT), respectively. Thirty well-characterized LA-positive and 30 LA-negative plasma samples were used to test the commercial assays. In some samples, both commercial tests failed to detect weak or moderately strong LAs. The sensitivity was 80% for the DVVtest+DVV confirm and 67% for the PTT-LA+Staclot LA. However, by applying both the two commercial tests to all plasma samples, 29 of 30 LA-positive plasma samples were diagnosed (sensitivity 97%). No false positive test results were found (specificity 100%).


Assuntos
Testes de Coagulação Sanguínea/métodos , Inibidor de Coagulação do Lúpus/análise , Estudos de Avaliação como Assunto , Humanos , Sensibilidade e Especificidade
7.
Thromb Res ; 72(4): 287-94, 1993 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-8303668

RESUMO

We have recently developed a computer-assisted, semi-automated test for lupus anticoagulants (LA), based on the Activated Partial Thromboplastin Time (APTT) and the Russell's Viper Venom Time (RVVT). In this test, plasma samples mixed 1:1 with pooled normal plasma are tested at one low (screening procedure) and one high (confirming procedure) cephalin concentration, using an automated clot timer. The ratio of these two clotting times, divided by the corresponding ratio for normal plasma, was defined as the Lupus Ratio (LR). Based on the LR of several dilutions of a strong LA positive plasma, a standard curve was constructed for LA quantitation in both the APTT and the RVVT system. In the present article, we discuss the use of different LA positive plasma as standards for the identification as well as quantitation of LA. Due to the heterogeneity of LA, the shape and slope of the standard curves as well as the cut-off points between "normal" and "pathological" values varied from one plasma to another. Thus, the result of LA quantitation of a given plasma varied considerably, according to the choice of standard plasma. A strong LA plasma should be chosen as a standard, since any standard plasma only allows the quantitation of plasmas with a lower LR than its own. A pool of several plasmas is also suitable as a standard. In addition to LA quantitation, such a standard could be used to define the cut-off between "normal" and "abnormal" results in each assay, as a certain dilution of the standard plasma. The present study also confirms the greater sensitivity of the APTT as compared to the RVVT for LA detection.


Assuntos
Inibidor de Coagulação do Lúpus/sangue , Adolescente , Adulto , Autoanálise , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tempo de Tromboplastina Parcial , Tempo de Protrombina , Padrões de Referência , Titulometria
8.
Thromb Res ; 86(5): 385-91, 1997 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-9211629

RESUMO

UNLABELLED: It is well known that plasmas with lupus anticoagulants (LA) may give false low activated protein C (APC) ratios, and these false positive tests are not necessarily corrected by mixing with factor V deficient plasma (FVdef). In the present study, we show that repeating the test after mixing 1 + 1 with pooled normal plasma (NP) instead of mixing with FVdef confirm the presence of the Leiden mutation (FV-Leiden) in patients with antiphospholipid antibodies (APA). Samples from sixteen patients with a low APC-ratio were examined. Eight samples contained APAs, including five samples with LA. RESULTS: The APC-ratios of eleven samples, including four with APAs, became normal when retested after mixing the plasma 1 + 1 with NP. All of them were heterozygous for FV-Leiden. One additional patient, who had partial correction of the APC-ratio, proved to be homozygous for the Leiden mutation. The remaining four samples, all of which had high positive tests for APAs, remained unchanged. One of these four was heterozygous for FV-Leiden, while the other three had normal FV. CONCLUSION: Normalisation of a low APC-ratio after dilution 1 + 1 with NP confirms the diagnosis of FV-Leiden. PCR analysis could be reserved for cases not affected by this procedure.


Assuntos
Anticorpos Antifosfolipídeos/sangue , Transtornos da Coagulação Sanguínea/sangue , Deficiência do Fator V/sangue , Deficiência do Fator V/diagnóstico , Proteína C/metabolismo , Proteína C/farmacologia , Transtornos da Coagulação Sanguínea/diagnóstico , Resistência a Medicamentos , Fator V/análise , Reações Falso-Positivas , Humanos , Inibidor de Coagulação do Lúpus/sangue , Tempo de Tromboplastina Parcial , Sensibilidade e Especificidade
9.
Thromb Res ; 57(2): 235-46, 1990 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-2107590

RESUMO

Lupus anticoagulants (LA) are IgG or IgM antibodies which prolong phospholipid-dependent coagulation tests. For the detection and quantitation of such antibodies, we have developed an ELISA with cephalin as the coating antigen. The sensitivity of this assay was compared to the activated partial thromboplastin time (APTT). LA was defined as greater than or equal to 5 sec prolongation of the APTT with standard cephalin dilution, or greater than or equal to 10 sec prolongation with a high cephalin dilution, on a 1:1 mixture of patient and control plasma. Plasma samples from 158 healthy individuals were tested for anticephalin antibodies. The 97.5 percentile was chosen as the upper reference limit and allocated a value of 1 ELISA unit. A "four-parameter logistic" model was used for transformation of the absorbances to ELISA units. Of 314 plasma samples referred for LA screening, positive results were found in 62 by both APTT and ELISA. Twenty-three samples were ELISA positive and APTT negative; this finding may be explained by greater sensitivity of the ELISA, which gave positive results in a four-fold greater dilution than the APTT. Prolongation of the APTT without antibody activity was found in 8 samples of which 2 had an inhibitor of factor VIII:C, the remaining 6 probably had true LA. In conclusion, our computer-assisted ELISA is a sensitive and reliable test method for quantitation of anticephalin antibodies. This assay has a high concordance with LA as detected with the APTT.


Assuntos
Autoanticorpos/análise , Fatores de Coagulação Sanguínea/imunologia , Ensaio de Imunoadsorção Enzimática , Fosfatidiletanolaminas/imunologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Fatores de Coagulação Sanguínea/análise , Computadores , Ensaio de Imunoadsorção Enzimática/normas , Feminino , Humanos , Inibidor de Coagulação do Lúpus , Masculino , Pessoa de Meia-Idade , Tempo de Tromboplastina Parcial
10.
Thromb Res ; 61(3): 201-11, 1991 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-1902996

RESUMO

Of 42 purified human myeloma proteins tested, two (IgG3 Her and IgM Mag) were found to possess strong lupus anticoagulant (LA) and anti-cephalin activity, as assessed by a dilute activated partial thromboplastin time (dAPTT) and ELISA test, respectively. For these proteins, we confirmed the observation reported by others that LA activity is present in the antigen-binding (Fab) portion of the immunoglobulin molecule. Rabbit anti-idiotype antibodies against IgG3 Her inhibited the anti-cephalin activity of this protein, suggesting that the anti-cephalin activity of IgG3 Her depends on the hypervariable part of the immunoglobulin and thus most probably is a true antigen-antibody reaction. The anti-Her idiotype antibodies were also able to bind to and inhibit the anti-cephalin activity of IgM Mag. ELISA binding and inhibition experiments showed that the anti-idiotype antiserum contained at least two sets of anti-idiotypes; one set that recognizes a cross-reactive idiotype shared by IgG3 Her and IgM Mag, and another set that seems to be unique to the immunizing protein IgG3 Her. Both sets of anti-idiotype antibodies also bound weakly to polyclonal (patient) IgG, indicating an idiotypic cross reaction.


Assuntos
Anticorpos Anti-Idiotípicos/análise , Anticorpos Monoclonais/imunologia , Fatores de Coagulação Sanguínea/imunologia , Coagulação Sanguínea/imunologia , Imunoglobulina G/análise , Fosfatidiletanolaminas/imunologia , Anticorpos Anti-Idiotípicos/imunologia , Fatores de Coagulação Sanguínea/análise , Ensaio de Imunoadsorção Enzimática , Humanos , Fragmentos Fab das Imunoglobulinas/análise , Fragmentos Fab das Imunoglobulinas/imunologia , Fragmentos Fc das Imunoglobulinas/análise , Fragmentos Fc das Imunoglobulinas/imunologia , Fragmentos de Imunoglobulinas/análise , Fragmentos de Imunoglobulinas/imunologia , Imunoglobulina G/imunologia , Imunoglobulina M/análise , Imunoglobulina M/imunologia , Inibidor de Coagulação do Lúpus , Tempo de Tromboplastina Parcial
11.
Thromb Res ; 66(1): 43-53, 1992 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-1412182

RESUMO

The effect of different methods of plasma preparation on the results of 1) a clotting assay for lupus anticoagulant (LA) detection (the dilute activated partial thromboplastin time, dAPTT), and of 2) an ELISA test for anticephalin antibody (aCEPHA) detection, was evaluated. It is well known that platelet disintegration resulting from freeze-thawing of plasma samples may release procoagulant phospholipid--"LA-bypassing" activity. Even with fresh plasma, the dAPTT of LA positive samples was sensitive to the presence of residual blood platelets. This effect was accentuated by freezing and thawing: with test plasma that had been prepared by a centrifugation force of 3,000 g or less for 15 min at 4 degrees C, freeze-thawing caused a significant shortening of the dAPTT. This phenomenon could not be demonstrated with filtered test plasma, which was platelet free. Surprisingly, ultracentrifugation also led to a substantial shortening of the dAPTT compared to filtered plasma, and should not be recommended as a method of plasma preparation for LA detection. The ELISA test was less sensitive to residual platelets than the dAPTT. Thus, plasma prepared by a centrifugation force of at least 1,500 g may be stored at -20 degrees C before performance of the ELISA test. For the dAPTT, filtering of test plasma and control plasma after centrifugation is recommended for maximum sensitivity, regardless of whether they are to be examined in the fresh state or after freezing and thawing.


Assuntos
Autoanticorpos/sangue , Inibidor de Coagulação do Lúpus/sangue , Fosfolipídeos/imunologia , Manejo de Espécimes/métodos , Testes de Coagulação Sanguínea , Ensaio de Imunoadsorção Enzimática , Congelamento , Humanos , Tempo de Tromboplastina Parcial
12.
Thromb Res ; 94(4): 213-20, 1999 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-10336236

RESUMO

This study was conducted to investigate whether antiphospholipid antibodies (APA) can interfere with the phospholipid-dependent inhibition of coagulation exerted by tissue factor pathway inhibitor (TFPI). Eleven patients with APA and eleven healthy controls matched for age and gender were enrolled. Blood samples were drawn before and 5 minutes after an intravenous injection of unfractionated heparin 5000 IE, which is known to cause TFPI release in healthy individuals. The preheparin samples showed significantly higher TFPI free antigen levels in the APA positive patients than in the controls (21.7 vs. 14.2 ng/ml, p = 0.03). TFPI activity as measured in a chromogenic substrate assay also was higher in patients, but this difference was not statistically significant (1.13 vs. 1.01 U/ml, p = 0.2). The TFPI levels showed a considerable rise in both patients and controls after heparin injection. In both assays, the postheparin levels were significantly higher in patients than in controls (TFPI antigen: 179 vs. 153 ng/ml, p = 0.05; TFPI activity: 3.26 vs. 2.51 U/ml, p = 0.03). A modified diluted prothrombin time assay (dPT) was used to measure TFPI anticoagulant activity. In this assay, samples from the patients with the strongest effect of lupus anticoagulants (LAs) on preheparin coagulation times showed little or no increase after heparin injection. This result may reflect an inhibition of TFPI anticoagulant activity by strong LAs. In conclusion, we have found that patients with APA have higher TFPI amidolytic activity/antigen level both before and after heparin stimulation of TFPI release. These observations do not explain the higher thrombotic risk in these patients but may reflect an upregulated tissue factor activity, which has been demonstrated in these patients. TFPI anticoagulant activity, however, as measured in a dPT assay, may be inhibited by strong LAs.


Assuntos
Anticorpos Antifosfolipídeos/sangue , Fibrinolíticos/farmacologia , Heparina/farmacologia , Lipoproteínas/sangue , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Trombose/sangue , Trombose/imunologia , Tempo de Coagulação do Sangue Total
13.
Thromb Res ; 35(1): 81-90, 1984 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-6474410

RESUMO

A prolongation of the thrombin clotting time by at least 25% was found in the presence of 8 of 26 IgG myeloma proteins, 2 of 5 IgA proteins and 1 of 10 macroglobulins, in a concentration of 10 mg/ml. Normal pooled immunoglobulin in concentrations up to 83 mg/ml were inactive. 2 IgG and 2 IgM monoclonal immunoglobulins caused an acceleration of the thrombin time by at least 20%; this phenomenon has not been reported before. Corresponding results were obtained with these proteins when the polymerization of des-AA and des-AABB fibrin monomers were investigated in a light scattering system. Studies with enzymatically produced Fab, F(ab')2 and Fc fragments from normal and monoclonal immunoglobulin suggested that the polymerization inhibitory activity resides in the Fab portion of the immunoglobulin molecule. While the ability to inhibit fibrin polymerization may be an immunoglobulin specific effect, the acceleration caused by certain other monoclonal immunoglobulins may be an unspecific effect similar to that seen with dextran or albumin.


Assuntos
Anticorpos Monoclonais , Produtos de Degradação da Fibrina e do Fibrinogênio/metabolismo , Fragmentos de Imunoglobulinas/metabolismo , Imunoglobulinas/metabolismo , Animais , Bovinos , Luz , Proteínas do Mieloma/metabolismo , Polímeros/metabolismo , Espalhamento de Radiação , Tempo de Trombina
14.
Thromb Res ; 69(2): 239-50, 1993 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-8446953

RESUMO

We describe the design of a quantitative test for lupus anticoagulants (LA), based on the Activated Partial Thromboplastin Time (APTT) and the Russell Viper Venom Time (RVVT). In this assay system, test plasmas mixed 1:1 with a pooled normal plasma (NP) are tested at a low as well as a high cephalin concentration, using an ACL 3000 automated clot timer. The ratio of these two clotting times, divided by the corresponding ratio for the NP, was defined as the Lupus Ratio (LR) and calculated by means of a computer program. The frequency distribution of the LR in a reference population of 150 healthy individuals was determined, and the 97.5 percentile was defined as the upper reference limit and allocated the value one Lupus Anticoagulant Unit (LA-U). Using dilutions of one strong LA positive plasma, standard curves for LA-U determination were constructed for the APTT as well as the RVVT based test, and fitted with a log-logit computer model. The sensitivity of the tests was comparable to that of the Kaolin Clotting Time (KCT). Plasma samples from warfarin treated patients were uniformly negative, while most heparin-containing plasmas were positive in both tests. Plasmas deficient in Factors V, VIII and IX were negative, whereas one Factor VIII-inhibitor containing plasma was positive in the APTT and negative in the RVVT. The present work shows that it is possible to adapt the APPT as well as the RVVT for LA quantification. With an automated clot timer and computer based calculation of results, the assays are simple and reproducible and have a high sensitivity and specificity.


Assuntos
Testes de Coagulação Sanguínea/métodos , Inibidor de Coagulação do Lúpus/sangue , Adulto , Idoso , Idoso de 80 Anos ou mais , Computadores , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes
15.
Thromb Res ; 40(4): 473-82, 1985 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-4082120

RESUMO

When a purified myeloma protein with the ability to inhibit fibrin polymerization was preincubated with sheep anti-human F(ab')2 antibodies, there was a marked reduction of the ability to prolong the thrombin clotting time, while anti-Fc antibodies had only a slight effect. A monoclonal immunoglobulin which shortens the thrombin time was uninfluenced by anti-F (ab')2 as well as by anti-Fc antibodies. Partial reduction and alkylation of the immunoglobulins did not modify their effect on the thrombin time. None of the immunoglobulins bound to fibrinogen or fibrin monomer that had been linked to CNBr-activated agarose. Myeloma proteins may interfere with fibrin polymerization in two ways: some proteins inhibit polymerization in a reaction that depends on the Fab (antigen binding) part of the molecule; however, antibody binding activity against fibrinogen or fibrin monomer has not been demonstrated. Other (rare) myeloma proteins accelerate fibrin polymerization; this effect cannot be ascribed to any particular portion of the molecule and is probably of an unspecific nature.


Assuntos
Anticorpos Monoclonais/imunologia , Fibrina/metabolismo , Animais , Complexo Antígeno-Anticorpo , Bovinos , Fibrinogênio/metabolismo , Fibrinopeptídeo A/análise , Fibrinopeptídeo B/análise , Fragmentos Fab das Imunoglobulinas , Fragmentos Fc das Imunoglobulinas , Substâncias Macromoleculares , Proteínas do Mieloma/imunologia
16.
Thromb Res ; 86(2): 141-52, 1997 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-9175235

RESUMO

We have recently shown that D-dimers are degraded by human neutrophil elastase (HNE) in vitro, causing rapid decrease in the D-dimer levels measured by a Latex test, but not with an ELISA test employing the same monoclonal antibody against D-dimer. To see if such discrepant D-dimer concentrations occurred in patients with high HNE concentration, we examined 80 plasma samples from 8 patients with sepsis with a Latex and an ELISA test and calculated the ratio between the D-dimer values obtained with the two tests. Twenty healthy pregnant and twenty pre-eclamptic patients, who are known to have raised D-dimer but low HNE concentrations, were chosen as controls. HNE levels were estimated by determining the HNE-alpha 1-proteinase inhibitor complex (HNE-A1PI) concentration. HNE-A1PI concentration was increased in sepsis patients compared with pre-eclamptic patients (p < 0.0005) and healthy pregnant women (p < 0.0005). In sepsis patients, the D-dimer results were skewed towards lower ratios between Latex and ELISA values compared to pre-eclamptic patients (p = 0.008) and healthy pregnant women (p = 0.0001). In plasma samples from patients with the largest discrepancy between Latex and ELISA D-dimer values, Western blotting with immunostaining indicated degradation of D-dimers to D-like fragments similar to those observed following degradation of cross-linked fibrin by HNE in vitro. We conclude that in sepsis patients there is a marked discrepancy between Latex and ELISA D-dimer values that may be caused by HNE. In such patients Latex D-dimer assays may cause severe underestimation of fibrinolysis.


Assuntos
Ensaio de Imunoadsorção Enzimática/métodos , Produtos de Degradação da Fibrina e do Fibrinogênio/análise , Testes de Fixação do Látex/métodos , Elastase de Leucócito/sangue , Sepse/sangue , Adulto , Estudos de Casos e Controles , Feminino , Fibrinólise , Humanos , Técnicas In Vitro , Masculino , Pessoa de Meia-Idade , Neutrófilos/enzimologia , Pré-Eclâmpsia/sangue , Gravidez , Sepse/enzimologia , alfa 1-Antitripsina/análise
17.
Thromb Res ; 104(4): 275-82, 2001 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-11728529

RESUMO

Although there is international consensus regarding the general principles of testing for lupus anticoagulants (LAs), no agreement exists as far as the analysis of the clotting time results is concerned. Twenty-nine laboratories participating in the Fifth International Survey of Lupus Anticoagulants (ISLA-5) reported the activated partial thromboplastin time (APTT)-based clotting times obtained on seven defined test samples and a normal plasma (NP) using the same two reagents with low and high phospholipid (PL) concentrations, respectively. These clotting times were used to analyse how various methods of calculating the results may influence the apparent sensitivity of LA tests. We found that the use of a separate screening test may lead to the exclusion of samples where the presence of LA would have been detected by a combined screening and confirmatory method. For instance, the dilute APTT (dAPTT) gave a sensitivity of 53.5% (screening test), while the calculation of a ratio between the clotting times obtained with two different PL concentrations gave a sensitivity of 68.1% (confirmatory test). The normalisation of results by dividing with the corresponding results of NP increased the apparent sensitivity. The screening test ratio between dAPTT results of test samples and NP gave a sensitivity of 84.7%. The normalised ratio between the clotting times obtained with the two reagents (lupus ratio, LR) gave a sensitivity of 95.1%. We conclude that when testing for LA, all samples should be tested with both low (screening procedure) and high (confirmatory procedure) PL concentrations. These two clotting times should be evaluated in relation to each other and to the corresponding results obtained with a reference plasma (normalisation).


Assuntos
Inibidor de Coagulação do Lúpus/análise , Testes de Coagulação Sanguínea/instrumentação , Testes de Coagulação Sanguínea/métodos , Testes de Coagulação Sanguínea/normas , Técnicas de Laboratório Clínico/instrumentação , Técnicas de Laboratório Clínico/normas , Interpretação Estatística de Dados , Relação Dose-Resposta a Droga , Humanos , Cooperação Internacional , Variações Dependentes do Observador , Fosfolipídeos/farmacologia , Padrões de Referência , Sensibilidade e Especificidade
18.
Pharmacoeconomics ; 16(4): 329-41, 1999 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-10623362

RESUMO

A review of current treatment options in multiple myeloma is presented, including data on health-related quality of life and pharmacoeconomics. For induction chemotherapy, no combination of cytostatic drugs has been shown to be consistently superior to the simple cyclic oral treatment with melphalan and prednisone that has been available for 30 years. The total resource consumption and direct costs per patient treated with melphalan and prednisone is approximately $US10,000 (1995 values). As median survival is prolonged from less than a year in untreated patients to 30 to 36 months, this treatment must be considered cost effective. Interferon-alpha has a modest effect on progression-free and overall survival when added to chemotherapy regimens. However, the high cost and toxicity of this drug results in an unfavourable cost-utility ratio, estimated to be between $US50,000 to $US100,000 per quality-adjusted life-year gained. Clinical trials suggest that high dose chemotherapy followed by autologous stem cell support administered to patients who have achieved disease stabilisation or objective response to conventional induction chemotherapy, prolongs median survival by about 1.5 years. Preliminary cost-utility analyses suggest a cost per life-year gained of $US30,000 to $US40,000. Further potential improvements of this therapeutic modality are under way. Several bisphosphonates have been tested for the ability to prevent the skeletal complications of multiple myeloma. Monthly infusions of pamidronate have been shown in 1 randomised trial to significantly reduce the rate of skeletal complications. Unfortunately, the rapid and widespread acceptance of this therapy seems to preclude further prospective, placebo-controlled trials with cost-utility evaluation.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/economia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/economia , Qualidade de Vida , Humanos , Ensaios Clínicos Controlados Aleatórios como Assunto
19.
Pharmacoeconomics ; 12(1): 89-103, 1997 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10169390

RESUMO

This study evaluated the cost utility of adding interferon-alpha 2b to conventional treatment in patients with multiple myeloma. It also provides a methodology for transforming complex quality-of-life profiles into a single index value on the conventional 0 to 1 quality-adjusted life-year scale (QALY). From 1990 to 1992, 583 patients with newly diagnosed, symptomatic multiple myeloma were enrolled in a randomised, multicentre, phase III study to evaluate the addition of interferon-alpha 2b to treatment with melphalan and prednisone. Addition of interferon-alpha 2b yielded a 12% increase in median survival time, at the expense of a slight reduction in quality of life during the first year of treatment. The gain in survival time was not large enough to reach statistical significance. Patients receiving interferon-alpha 2b also had a 5- to 6-month prolongation of the plateau phase. Cost per QALY gained by adding interferon-alpha 2b was conservatively estimated at $US110,000. Potentially better cost effectiveness may be found in different treatment regimens or in certain patient subgroups.


Assuntos
Análise Custo-Benefício/economia , Interferon-alfa/economia , Melfalan/economia , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/economia , Prednisona/economia , Idoso , Combinação de Medicamentos , Feminino , Humanos , Interferon-alfa/uso terapêutico , Masculino , Melfalan/uso terapêutico , Pessoa de Meia-Idade , Prednisona/uso terapêutico , Qualidade de Vida
20.
Med Oncol ; 18(1): 65-77, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11778972

RESUMO

In a population-based study, the Nordic Myeloma Study Group found a survival advantage for high-dose melphalan with autologous blood stem-cell support compared to conventional chemotherapy in myeloma patients under 60 yr of age (risk ratio: 1.62; confidence interval [CI] 1.22-2.15; p = 0.001). A study of health-related quality of life (HRQoL) was integrated in the trial, using the EORTC QLQ-C30 questionnaire. Of the 274 patients receiving intensive therapy 221 (81%) were compared to 113 (94%) of 120 patients receiving conventional melphalan-prednisone treatment. Prior to treatment, there were no statistically significant differences in any HRQoL score between the two groups. One month after the start of induction chemotherapy, the patients on intensive treatment had more sleep disturbance than the control patients. At 6 mo, corresponding to a mean of 52 d after high-dose melphalan, the patients on intensive treatment had moderately lower scores for global QoL and role and social functioning and there was also a significantly higher score for appetite loss. At 12 and 24 mo, the HRQoL was similar to that of the control patients. At 36 mo, there was a trend toward less fatigue, pain, nausea, and appetite loss in the intensive-treatment group. Thus, the 18 mo of prolonged survival seem to be associated with a good health-related quality of life. Despite the moderate HRQoL reduction associated with the early intensive chemotherapy phase, this treatment modality must be regarded as an important step forward in the care of multiple myeloma.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Nível de Saúde , Mieloma Múltiplo/tratamento farmacológico , Qualidade de Vida , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Apetite , Feminino , Transplante de Células-Tronco Hematopoéticas , Humanos , Masculino , Melfalan/administração & dosagem , Pessoa de Meia-Idade , Estudos Prospectivos , Transtornos do Sono-Vigília/induzido quimicamente , Comportamento Social , Apoio Social , Análise de Sobrevida
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