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1.
Rev Med Interne ; 42(5): 302-309, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33518414

RESUMO

INTRODUCTION: In France, at the end of the sixth year of medical studies, students take a national ranking examination including progressive clinical case-based multiple-choice questions (MCQs). We aimed to evaluate the ability of these MCQs for testing higher-order thinking more than knowledge recall, and to identify their characteristics associated with success and discrimination. METHODS: We analysed the 72 progressive clinical cases taken by the students in the years 2016-2019, through an online platform. RESULTS: A total of 72 progressive clinical cases (18 for each of the 4 studied years), corresponding to 1059 questions, were analysed. Most of the clinical cases (n=43, 60%) had 15 questions. Clinical questions represented 89% of all questions, whereas basic sciences questions accounted for 9%. The most frequent medical subspecialties were internal medicine (n=90, 8%) and infectious diseases (n=88, 8%). The most frequent question types concerned therapeutics (26%), exams (19%), diagnosis (14%), and semiology (13%). Level 2 questions ("understand and apply") accounted for 59% of all questions according to the Bloom's taxonomy. The level of Bloom's taxonomy significantly changed over time with a decreasing number of level 1 questions ("remember") (P=0.04). We also analysed the results of the students among 853 questions of training ECNi. Success and discrimination significantly decreased when the number of correct answers increased (P<0.0001 both). The success, discrimination, mean score, and mean number of discrepancies did not differ according to the diagnosis, exam, imaging, semiology, or therapeutic type of questions. CONCLUSION: Progressive clinical case-based MCQs represent an innovative way to evaluate undergraduate students.


Assuntos
Estudantes de Medicina , Avaliação Educacional , França/epidemiologia , Humanos
3.
Leukemia ; 32(1): 83-91, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28592889

RESUMO

In the phase 3 RESONATE study, ibrutinib demonstrated superior progression-free survival (PFS), overall survival (OS) and overall response rate (ORR) compared with ofatumumab in relapsed/refractory CLL patients with high-risk prognostic factors. We report updated results from RESONATE in these traditionally chemotherapy resistant high-risk genomic subgroups at a median follow-up of 19 months. Mutations were detected by Foundation One Heme Panel. Baseline mutations in the ibrutinib arm included TP53 (51%), SF3B1 (31%), NOTCH1 (28%), ATM (19%) and BIRC3 (14%). Median PFS was not reached, with 74% of patients randomized to ibrutinib alive and progression-free at 24 months. The improved efficacy of ibrutinib vs ofatumumab continues in all prognostic subgroups including del17p and del11q. No significant difference within the ibrutinib arm was observed for PFS across most genomic subtypes, although a subset carrying both TP53 mutation and del17p had reduced PFS compared with patients with neither abnormality. Reduced PFS or OS was not evident in patients with only del17p. PFS was significantly better for ibrutinib-treated patients in second-line vs later lines of therapy. The robust clinical activity of ibrutinib continues to show ongoing efficacy and acceptable safety consistent with prior reports, independent of various known high-risk mutations.


Assuntos
Leucemia Linfocítica Crônica de Células B/patologia , Mutação/genética , Adenina/análogos & derivados , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Monoclonais/uso terapêutico , Anticorpos Monoclonais Humanizados , Antineoplásicos/uso terapêutico , Intervalo Livre de Doença , Feminino , Seguimentos , Humanos , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Leucemia Linfocítica Crônica de Células B/mortalidade , Masculino , Pessoa de Meia-Idade , Mutação/efeitos dos fármacos , Recidiva Local de Neoplasia/tratamento farmacológico , Recidiva Local de Neoplasia/mortalidade , Recidiva Local de Neoplasia/patologia , Piperidinas , Prognóstico , Pirazóis/uso terapêutico , Pirimidinas/uso terapêutico , Proteína Supressora de Tumor p53/genética
5.
Rev Med Interne ; 37(3): 166-72, 2016 Mar.
Artigo em Francês | MEDLINE | ID: mdl-26827272

RESUMO

BACKGROUND: The year 2016 will be pivotal for the evaluation of French medical students with the introduction of the first computerized National Ranking Test (ECNi). The SIDES, online electronic system for medical student evaluation, was created for this purpose. All the universities have already organized faculty exams but few a joint computerized ranking test at several universities simultaneously. We report our experience on the organization of a mock ECNi by universities Paris Descartes, Paris Diderot and Paris 13. METHODS: Docimological, administrative and technical working groups were created to organize this ECNi. Students in their fifth year of medical studies, who will be the first students to sit for the official ECNi in 2016, were invited to attend this mock exam that represented more than 50% of what will be proposed in 2016. A final electronic questionnaire allowed a docimological and organizational evaluation by students. An analysis of ratings and rankings and their distribution on a 1000-point scale were performed. RESULTS: Sixty-four percent of enrolled students (i.e., 654) attended the three half-day exams. No difference in total score and ranking between the three universities was observed. Students' feedback was extremely positive. Normalized over 1000 points, 99% of students were scored on 300 points only. Progressive clinical cases were the most discriminating test. CONCLUSION: The organization of a mock ECNi involving multiple universities was a docimological and technical success but required an important administrative, technical and teaching investment.


Assuntos
Computadores , Avaliação Educacional/métodos , Docentes de Medicina , Retroalimentação , Estudantes de Medicina , Inquéritos e Questionários , Universidades , Atitude do Pessoal de Saúde , Comportamento do Consumidor , Docentes de Medicina/psicologia , Humanos , Paris , Satisfação Pessoal , Universidades/organização & administração , Universidades/normas
7.
Leukemia ; 30(4): 929-36, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26639181

RESUMO

In chronic lymphocytic leukemia (CLL) the level of minimal residual disease (MRD) after therapy is an independent predictor of outcome. Given the increasing number of new agents being explored for CLL therapy, using MRD as a surrogate could greatly reduce the time necessary to assess their efficacy. In this European Research Initiative on CLL (ERIC) project we have identified and validated a flow-cytometric approach to reliably quantitate CLL cells to the level of 0.0010% (10(-5)). The assay comprises a core panel of six markers (i.e. CD19, CD20, CD5, CD43, CD79b and CD81) with a component specification independent of instrument and reagents, which can be locally re-validated using normal peripheral blood. This method is directly comparable to previous ERIC-designed assays and also provides a backbone for investigation of new markers. A parallel analysis of high-throughput sequencing using the ClonoSEQ assay showed good concordance with flow cytometry results at the 0.010% (10(-4)) level, the MRD threshold defined in the 2008 International Workshop on CLL guidelines, but it also provides good linearity to a detection limit of 1 in a million (10(-6)). The combination of both technologies would permit a highly sensitive approach to MRD detection while providing a reproducible and broadly accessible method to quantify residual disease and optimize treatment in CLL.


Assuntos
Antígenos CD/metabolismo , Citometria de Fluxo/normas , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Leucemia Linfocítica Crônica de Células B/terapia , Neoplasia Residual/diagnóstico , Adolescente , Adulto , Terapia Combinada , Europa (Continente) , Feminino , Seguimentos , Humanos , Imunofenotipagem , Leucemia Linfocítica Crônica de Células B/patologia , Masculino , Estadiamento de Neoplasias , Neoplasia Residual/genética , Neoplasia Residual/metabolismo , Prognóstico , Adulto Jovem
8.
Leukemia ; 27(1): 142-9, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23041722

RESUMO

Detection of minimal residual disease (MRD) in chronic lymphocytic leukaemia (CLL) is becoming increasingly important as treatments improve. An internationally harmonised four-colour (CLR) flow cytometry MRD assay is widely used but has limitations. The aim of this study was to improve MRD analysis by identifying situations where a less time-consuming CD19/CD5/κ/λ analysis would be sufficient for detecting residual CLL, and develop a six-CLR antibody panel that is more efficient for cases requiring full MRD analysis. In 784 samples from CLL patients after treatment, it was possible to determine CD19/CD5/κ/λ thresholds that identified cases with detectable MRD with 100% positive predictive value (PPV). However, CD19/CD5/κ/λ analysis was unsuitable for predicting iwCLL/NCI response status or identifying cases with no detectable MRD. For the latter cases requiring a full MRD assessment, a six-CLR assay was designed comprising CD19/CD5/CD20 with (1) CD3/CD38/CD79b and (2) CD81/CD22/CD43. There was good correlation between four-CLR and six-CLR panels in dilution studies and clinical samples, with 100% concordance for detection of residual disease at the 0.01% (10(-4)) level (n=59) and good linearity even at the 0.001-0.01% (10(-5)-10(-4)) level. A six-CLR panel therefore provides equivalent results to the four-CLR panel but it requires fewer reagents, fewer cells and a much simpler analysis approach.


Assuntos
Biomarcadores Tumorais/análise , Citometria de Fluxo/normas , Leucemia Linfocítica Crônica de Células B/patologia , Neoplasia Residual/diagnóstico , Antígenos CD/análise , Europa (Continente) , Humanos , Cadeias Leves de Imunoglobulina/imunologia , Cadeias kappa de Imunoglobulina/imunologia , Cadeias lambda de Imunoglobulina/imunologia , Imunofenotipagem , Leucemia Linfocítica Crônica de Células B/imunologia , Estadiamento de Neoplasias , Neoplasia Residual/imunologia , Prognóstico , Sensibilidade e Especificidade
9.
Leukemia ; 26(7): 1458-61, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22297721

RESUMO

Recent evidence suggests that - in addition to 17p deletion - TP53 mutation is an independent prognostic factor in chronic lymphocytic leukemia (CLL). Data from retrospective analyses and prospective clinical trials show that ∼5% of untreated CLL patients with treatment indication have a TP53 mutation in the absence of 17p deletion. These patients have a poor response and reduced progression-free survival and overall survival with standard treatment approaches. These data suggest that TP53 mutation testing warrants integration into current diagnostic work up of patients with CLL. There are a number of assays to detect TP53 mutations, which have respective advantages and shortcomings. Direct Sanger sequencing of exons 4-9 can be recommended as a suitable test to identify TP53 mutations for centers with limited experience with alternative screening methods. Recommendations are provided on standard operating procedures, quality control, reporting and interpretation. Patients with treatment indications should be investigated for TP53 mutations in addition to the work-up recommended by the International workshop on CLL guidelines. Patients with TP53 mutation may be considered for allogeneic stem cell transplantation in first remission. Alemtuzumab-based regimens can yield a substantial proportion of complete responses, although of short duration. Ideally, patients should be treated within clinical trials exploring new therapeutic agents.


Assuntos
Cromossomos Humanos Par 17/genética , Leucemia Linfocítica Crônica de Células B/genética , Mutação/genética , Guias de Prática Clínica como Assunto , Proteína Supressora de Tumor p53/genética , Humanos , Leucemia Linfocítica Crônica de Células B/diagnóstico , Leucemia Linfocítica Crônica de Células B/terapia , Prognóstico
11.
Eur J Anaesthesiol ; 25(12): 1002-8, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18471336

RESUMO

BACKGROUND AND OBJECTIVE: Blood oxygen concentration decrease may be associated with haemostatic impairments. We aimed to study the effect of oxygen decrease in a rabbit model of thrombosis and bleeding. METHODS: A total of 44 rabbits were anaesthetized, ventilated and monitored for blood pressure, blood arterial gas, temperature and carotid blood flow. The Folts model was used: a stenosis (75%) and an injury were carried out on the carotid artery, inducing thrombosis. Blood flow decreased as thrombus size increased until the pressure gradient was such that the thrombus was released and local arterial blood flow was suddenly restored. This is known as a cyclic flow reduction. After counting baseline cyclic flow reductions during a 20-min period (P1), rabbits were randomized blindly to one of three groups: hyperoxic, FiO2=100%; normoxic, FiO2 was decreased to obtain a PaO2 between 80 and 120 mmHg; hypoxic, PaO2 < 80 mmHg. Then CFRs were recorded over a second 20-min period (P2). At the end of the experiment, a hepatosplenic section was done and the amount of blood loss was recorded. After each period, the following parameters were measured: blood gas, ear-immersion bleeding time, haemoglobin, platelet count, prothrombin time, activated partial thromboplastin time and fibrinogen. RESULTS: Oxygen decrease during hypoxic and normoxic periods was associated with a decrease in cyclic flow reductions. Bleeding time increased in the hypoxic group unless hepatosplenic bleeding remained stable. A slight increase in activated partial thromboplastin time was observed in the normoxic and hypoxic groups. CONCLUSION: An abrupt decrease in oxygen administration was responsible for an antithrombotic effect. Increase in bleeding time occurred during hypoxia. No clinically relevant variation of any haemostasis parameters was observed.


Assuntos
Lesões das Artérias Carótidas/fisiopatologia , Trombose das Artérias Carótidas/fisiopatologia , Estenose das Carótidas/fisiopatologia , Hemorragia/fisiopatologia , Hipóxia/complicações , Animais , Tempo de Sangramento , Velocidade do Fluxo Sanguíneo , Gasometria , Lesões das Artérias Carótidas/sangue , Trombose das Artérias Carótidas/sangue , Trombose das Artérias Carótidas/etiologia , Estenose das Carótidas/sangue , Modelos Animais de Doenças , Hemorragia/sangue , Masculino , Agregação Plaquetária , Coelhos , Distribuição Aleatória
12.
J Thromb Haemost ; 5(2): 244-9, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17129221

RESUMO

BACKGROUND: Recombinant activated factor VII (rFVIIa) is increasingly used to secure hemostasis in hemorrhagic situations in trauma and surgical patients. Hypothermia is often observed in these clinical settings. OBJECTIVE: To study the efficacy and safety of rFVIIa in hypothermia in a rabbit model of bleeding and thrombosis. METHODS: Sixty-nine rabbits were anesthetized, ventilated and monitored for blood pressure, temperature and carotid flow. The Folts model was used: a stenosis (75%) and an injury were carried out on the carotid artery, inducing thrombosis. Blood flow decreased as thrombus size increased until the pressure gradient was such that the thrombus was released and local arterial blood flow was suddenly restored. This is known as a cyclic flow reduction (CFR). After counting baseline CFRs during a 20-min period (P1), rabbits were randomized blindly to one of four groups: normothermic (NT) placebo or rFVIIa (150 microg kg(-1)), hypothermic (HT) (34 degrees C) placebo or rFVIIa. Then CFRs were recorded over a second period (P2). At the end of the experiment, a hepato-splenic section was performed and the amount of blood loss was recorded. After each period, the following were measured: ear immersion bleeding time (BT), hemoglobin, platelet count, prothrombin time (PT), activated partial thromboplastin time (aPTT) and fibrinogen. RESULTS: Hypothermia increased BT and blood loss. These effects were reversed by rFVIIa. In NT rabbits, rFVIIa shortened BT but did not reduce blood loss. rFVIIa-treated rabbits bled similarly regardless of temperature. The incidence of CFRs was higher in treated than placebo animals regardless of temperature. rFVIIa decreased PT and aPTT without modifying platelet count or fibrinogen level. CONCLUSION: Hemostatic efficacy of rFVIIa was maintained in hypothermia. However, the number of CFRs was higher in the rFVIIa-treated group than in the placebo groups, whether for NT or HT rabbits.


Assuntos
Fator VII/uso terapêutico , Hemorragia/tratamento farmacológico , Hipotermia , Trombose/induzido quimicamente , Animais , Modelos Animais de Doenças , Fator VIIa , Hemorragia/complicações , Hemostasia , Coelhos , Proteínas Recombinantes/uso terapêutico , Fluxo Sanguíneo Regional , Método Simples-Cego
14.
Leukemia ; 18(5): 953-61, 2004 May.
Artigo em Inglês | MEDLINE | ID: mdl-15029207

RESUMO

Nodal mantle cell lymphoma (MCL) is a well-defined entity, but non-nodal leukemic cyclin D1 positive lymphoproliferative disorders have been reported and their relationship with MCL remains controversial and their prognosis heterogeneous. We prospectively studied the expression of cyclin D1 in CD5 positive leukemic B lymphoproliferative disorders at diagnosis and identified 65 cases overexpressing cyclin D1. We did not distinguish any clinical or biological criteria allowing one to identify a non-MCL group. Multivariate analysis identified age, anemia and p27kip1 expression as independent prognostic factors of survival. By univariate analysis, p27kip1 high expression proved to be the strongest predictor of prolonged survival. The median survival of p27 low expressors was 30 months, while it was not reached for p27 high expressors. A high level of p27 expression was often found associated with the absence of nodal involvement and the presence of somatic mutations, but neither of them was restricted to the p27 high expression group. In conclusion, we hypothesize that MCL and these cyclin D1 positive leukemic lymphoproliferative disorders represent a continuous spectrum of diseases. Determination of p27 expression level appears as a routine applicable test allowing identification of a subset of patients who could be considered for different therapeutic approaches.


Assuntos
Proteínas de Ciclo Celular/análise , Ciclina D1/análise , Transtornos Linfoproliferativos/metabolismo , Proteínas Supressoras de Tumor/análise , Adulto , Idoso , Aberrações Cromossômicas , Inibidor de Quinase Dependente de Ciclina p27 , Feminino , Genes de Imunoglobulinas , Humanos , Cadeias Pesadas de Imunoglobulinas/genética , Região Variável de Imunoglobulina/genética , Imunofenotipagem , Transtornos Linfoproliferativos/genética , Transtornos Linfoproliferativos/imunologia , Masculino , Pessoa de Meia-Idade , Prognóstico
15.
Leukemia ; 17(12): 2435-43, 2003 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-14523476

RESUMO

Flavopiridol, an inhibitor of cyclin-dependent kinases and other protein kinases, induces in vitro apoptosis of malignant cells from B-cell chronic lymphocytic leukemia (B-CLL). Previously, we reported that nitric oxide (NO), produced by an inducible NO synthase (iNOS), spontaneously expressed by the B-CLL cells, contributed to their deficiency in apoptosis. In the present work, we show that ex vivo treatment of leukemic cells from B-CLL patients with flavopiridol results in the inhibition of iNOS expression, as determined by immunofluorescence and Western blotting, and in a marked inhibition of NO production measured in situ with a specific fluorescent probe (DAF-2 DA). These effects are accompanied by membrane, mitochondrial and nuclear events of apoptosis. Flavopiridol exposure also results in the stimulation of caspase 3 activity and in caspase-dependent cleavage of p27(kip1), a negative regulator of the cell cycle, which is overexpressed in B-CLL. Thus, flavopiridol is capable of downregulating both iNOS and p27(kip1) expression in B-CLL cells. Furthermore, flavopiridol-promoted apoptosis is partly reverted by an NO donor, suggesting that inhibition of the NO pathway could participate in the apoptotic effects of flavopiridol on the leukemic cells.


Assuntos
Antineoplásicos/farmacologia , Proteínas de Ciclo Celular/metabolismo , Flavonoides/farmacologia , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Leucemia Linfocítica Crônica de Células B/metabolismo , Óxido Nítrico Sintase/metabolismo , Piperidinas/farmacologia , Proteínas Supressoras de Tumor/metabolismo , Idoso , Apoptose/efeitos dos fármacos , Inibidor de Quinase Dependente de Ciclina p27 , Regulação para Baixo/efeitos dos fármacos , Feminino , Humanos , Técnicas In Vitro , Masculino , Pessoa de Meia-Idade , Óxido Nítrico/metabolismo , Doadores de Óxido Nítrico/farmacologia , Óxido Nítrico Sintase Tipo II
16.
Leukemia ; 17(6): 1104-11, 2003 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12764376

RESUMO

B-cell chronic lymphocytic leukemia (B-CLL) is characterized by the accumulation of growth arrested clonal B lymphocytes that undergo apoptosis when treated with fludarabine. To further explore the mechanism for the cell cycle arrest, we examined the expression and activity of cyclin-dependent kinases and inhibitors in primary B-CLL cells. We observed high levels of p27kip1, cyclin D2, cyclin E, cdk2, and cdk4 expression in freshly isolated B-CLL cells. Despite high levels of cyclins and cdks, little cdk2 or cdk4 activity was observed with p27kip1 in complex with cyclinD2/cdk4 and cyclin E/cdk2. Remarkably, when B-CLL cells were treated in vitro with fludarabine, p27kip1 underwent caspase-specific degradation accompanied by an increase in cdk4 activity. We conclude that the G0/G1 arrest of B-CLL cells may protect against apoptosis and that the decrease in p27kip1 expression by caspase cleavage may be a key step in chemotherapy-induced apoptosis in B-CLL.


Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Quinases relacionadas a CDC2 e CDC28 , Caspases/metabolismo , Proteínas de Ciclo Celular/metabolismo , Leucemia Linfocítica Crônica de Células B/patologia , Proteínas Proto-Oncogênicas , Proteínas Supressoras de Tumor/metabolismo , Vidarabina/análogos & derivados , Vidarabina/farmacologia , Western Blotting , Inibidores de Caspase , Ciclo Celular/efeitos dos fármacos , Ciclina D2 , Ciclina E/metabolismo , Quinase 2 Dependente de Ciclina , Quinase 4 Dependente de Ciclina , Inibidor de Quinase Dependente de Ciclina p27 , Quinases Ciclina-Dependentes/metabolismo , Ciclinas/metabolismo , Inibidores Enzimáticos/farmacologia , Humanos , Marcação In Situ das Extremidades Cortadas , Leucemia Linfocítica Crônica de Células B/enzimologia , Testes de Precipitina , Proteínas Serina-Treonina Quinases/metabolismo , Frações Subcelulares , Células Tumorais Cultivadas
17.
Leukemia ; 17(1): 133-7, 2003 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-12529670

RESUMO

In B-CLL IgV(H) genes mutational status is a major prognostic factor. Since sequencing of IgV(H) genes is not available in most laboratories, an easily performed surrogate assay is desirable. To identify the best surrogate assay, and to better discriminate prognostic subgroups we analyzed clinical and biological data from 58 typical CLL cases. A higher serum thymidine kinase level (>15 U/l) proved to be a strong predictor of mutational status, and the only independent one among the studied parameters. To further identify prognostic subgroups, cluster analysis was employed on 38 cases on which all data were available, which segregated two groups including 25 and 13 patients, respectively. These two clusters differed by their proliferative potential and appeared to discriminate patients with very different clinical course and outcome. s-TK was strikingly different among these two clusters, suggesting that s-TK level could be used routinely to identify patients at risk of progression.


Assuntos
Linfócitos B/imunologia , Biomarcadores Tumorais , Genes de Imunoglobulinas/genética , Região Variável de Imunoglobulina/genética , Leucemia Linfocítica Crônica de Células B/genética , Leucemia Linfocítica Crônica de Células B/imunologia , Mutação , Timidina Quinase/sangue , Idoso , Antígenos CD/imunologia , Proteínas de Ciclo Celular/metabolismo , Ciclina D2 , Inibidor de Quinase Dependente de Ciclina p27 , Ciclinas/metabolismo , Progressão da Doença , Feminino , Humanos , Imunofenotipagem , L-Lactato Desidrogenase/metabolismo , Leucemia Linfocítica Crônica de Células B/diagnóstico , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Valor Preditivo dos Testes , Prognóstico , Taxa de Sobrevida , Proteínas Supressoras de Tumor/metabolismo , Microglobulina beta-2/metabolismo
18.
Leukemia ; 16(12): 2438-46, 2002 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-12454750

RESUMO

Recent work suggests that chronic lymphocytic leukemia (B-CLL) expressing unmutated immunoglobulin V genes could correspond to the proliferation of naive B cells whereas those expressing mutated genes, may correspond to the proliferation of post-germinal center B cells. Current data from gene profiling expression have failed to demonstrate a clear-cut distinction between these two forms of B-CLL disease. In the present study, we have investigated the complete V(H) nucleotide sequence and the presence of RNA transcripts from different C(H) domains in 25 B-CLL patients. Our results demonstrate that: (1) expression of IgD is not related to the mutational frequency and activation of the isotype switch pathway; (2) isotype switch, leading to simultaneous expression at the transcriptional and protein level of IgM, IgD, IgG and IgA, occurs in a small percentage of patients, and (3) different mechanisms such as VDJ duplication and trans-splicing or RNA splicing of long nuclear transcript, could be involved in isotype switch. Our results highlight the difficulty in assigning a normal counterpart to B-CLL cells and raise the possibility that a different B cell development pathway, independent from classical germinal centers, might exist in B-CLL.


Assuntos
Linfócitos B/imunologia , Genes de Imunoglobulinas/genética , Switching de Imunoglobulina/genética , Memória Imunológica , Leucemia Linfocítica Crônica de Células B/imunologia , Mutação , Adulto , Idoso , Idoso de 80 Anos ou mais , Sequência de Aminoácidos , Feminino , Humanos , Cadeias Pesadas de Imunoglobulinas/genética , Isotipos de Imunoglobulinas/genética , Região Variável de Imunoglobulina/genética , Leucemia Linfocítica Crônica de Células B/genética , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Fenótipo , RNA Mensageiro/análise
20.
Leukemia ; 15(4): 559-66, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11368357

RESUMO

Characteristics of treatment-induced cell cycle arrest are important for in vitro and in vivo sensitivity of acute myeloid leukemia (AML) cells to cytotoxic drugs. We analyzed the expression of the major G1 cell cycle regulators (p21Cip1, p27Kip1, cyclins D, cyclin E and pRb) in 41 fresh AML cell samples. The level of p27 expression was the only factor correlated with the response to chemotherapy, a high level of p27 expression being predictive of complete remission. There was a close relation between expression of pRb, cyclin D2 and FAB subtype, illustrated by the absence of both proteins in most samples having a monocytic component (M4, M5). We also assessed the expressions of pRb, cyclin E, p21 and p27 and the activity of cdk2, the major regulator of S-phase entry, after exposure to cytosine-arabinoside (AraC) and daunorubicin (DNR), and found these proteins could characterize time- and dose-dependent cellular response to each drug. We observed hyperphosphorylated pRb, increased levels of cyclin E and a high cdk2 activity, but no p21 induction, in AML cells exposed to 10(-6) M AraC. After exposure to 10(-5) M AraC, corresponding to the serum concentration reached in high-dose AraC regimens (HDAraC), a strong p21 induction was observed, associated with similarly overexpressed cyclin E and even higher cdk2 activity than after 10(-6) M AraC, while apoptosis was significantly increased. These data suggest that cdk2 activity is likely to play a role in AraC-induced apoptosis in AML cells. This mechanism may account for high efficacy of HDAraC in cells showing little sensitivity to conventional AraC doses.


Assuntos
Quinases relacionadas a CDC2 e CDC28 , Proteínas de Ciclo Celular , Ciclina E/análise , Ciclinas/análise , Leucemia Mieloide Aguda/metabolismo , Proteínas Associadas aos Microtúbulos/análise , Proteína do Retinoblastoma/análise , Proteínas Supressoras de Tumor , Apoptose , Ciclina D , Quinase 2 Dependente de Ciclina , Inibidor de Quinase Dependente de Ciclina p21 , Inibidor de Quinase Dependente de Ciclina p27 , Quinases Ciclina-Dependentes/análise , Citarabina/farmacologia , Dano ao DNA , Daunorrubicina/farmacologia , Humanos , Interleucina-3/farmacologia , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/patologia , Proteínas Serina-Treonina Quinases/análise , Fator de Células-Tronco/farmacologia
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