Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 70
Filtrar
1.
Ann Oncol ; 25(4): 773-780, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24351401

RESUMO

Insights into tumour biology of breast cancer have led the path towards the introduction of targeted treatment approaches; still, breast cancer-related mortality remains relatively high. Efforts in the field of basic research revealed new druggable targets which now await validation within the context of clinical trials. Therefore, questions concerning the optimal design of future studies are becoming even more pertinent. Aspects such as the ideal end point, availability of predictive markers to identify the optimal cohort for drug testing, or potential mechanisms of resistance need to be resolved. An expert panel representing the academic community, the pharmaceutical industry, as well as European Regulatory Authorities met in Vienna, Austria, in November 2012, in order to discuss breast cancer biology, identification of novel biological targets and optimal drug development with the aim of treatment individualization. This article summarizes statements and perspectives provided by the meeting participants.


Assuntos
Receptor ErbB-2/genética , Neoplasias de Mama Triplo Negativas/patologia , Neoplasias de Mama Triplo Negativas/terapia , Ensaios Clínicos como Assunto , Feminino , Humanos , Terapia de Alvo Molecular , Transdução de Sinais , Neoplasias de Mama Triplo Negativas/classificação , Neoplasias de Mama Triplo Negativas/genética
3.
Ann Oncol ; 21(8): 1573-1578, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20133383

RESUMO

BACKGROUND: Drug development traditionally has relied upon the complementary contributions of clinicians and scientists at academic institutions and at pharmaceutical companies. Greater regulatory burdens, increased bureaucratic requirements, restricted reimbursement, and spiralling research and development costs are exerting pressure on the drug development pipeline. The result is a de-emphasis of exploratory research, particularly independent academic research, despite its proven value in identifying new drug targets and developing innovative cancer therapies. DESIGN: An expert panel assembled by the Biotherapy Development Association-a nonprofit international forum for academic and industry researchers, patients, and government regulatory and postregulatory agencies-examined the growing schism between academia and industry and identified several causes of declining academic research. RESULTS: The authors propose solutions to sustain investigator-initiated research and provide a new model whereby expert organisations provide a forum for academia and industry to plan studies within a regulatory framework to support licensure/authorisation and reimbursement for new molecularly targeted agents and biomarkers. CONCLUSIONS: Investigator-initiated trials have led to the discovery and development of innovative, safe, and effective cancer treatments. To ensure that such research continues, action will be required on the parts of legislative and regulatory bodies, industry, universities, patient advocacy organisations, and preclinical and clinical academic scientists.


Assuntos
Antineoplásicos/uso terapêutico , Ensaios Clínicos como Assunto , Neoplasias/tratamento farmacológico , Pesquisadores , Humanos
5.
Ann Oncol ; 20(3): 403-12, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18854550

RESUMO

To air challenging issues related to patient and market access to new anticancer agents, the Biotherapy Development Association--an international group focused on developing targeted cancer therapies using biological agents--convened a meeting on 29 November 2007 in Brussels, Belgium. The meeting provided a forum for representatives of pharmaceutical companies and academia to interact with European regulatory and postregulatory agencies. The goal was to increase all parties' understanding of their counterparts' roles in the development, licensure, and appraisal of new agents for cancer treatment, events guided by an understanding that cancer patients should have rapid and equitable access to life-prolonging treatments. Among the outcomes of the meeting were a greater understanding of the barriers facing drug developers in an evolving postregulatory world, clarity about what regulatory and postregulatory bodies expect to see in dossiers of new anticancer agents as they contemplate licensure and reimbursement, and several sets of recommendations to optimize patients' access to innovative, safe, effective, and fairly priced cancer treatments.


Assuntos
Antineoplásicos/provisão & distribuição , Acessibilidade aos Serviços de Saúde , Antineoplásicos/economia , Europa (Continente) , Humanos , Mecanismo de Reembolso
6.
Ann Oncol ; 20(11): 1771-85, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19608616

RESUMO

BACKGROUND: Treatment options for patients with metastatic breast cancer (MBC) include a rapidly expanding repertoire of medical, surgical and supportive care measures. DESIGN: To provide timely and evidence-based recommendations for the diagnostic workup and treatment of patients with MBC, an international expert panel reviewed and discussed the evidence available from clinical trials regarding diagnostic, therapeutic and supportive measures with emphasis on their impact on the quality of life and overall survival of patients with MBC. RESULTS: Evidence-based recommendations for the diagnostic workup, endocrine therapy, chemotherapy, use of targeted therapies and bisphosphonates, surgical treatment and supportive care measures in the management of patients with MBC were formulated. CONCLUSIONS: The present consensus manuscript updates evidence-based recommendations for state-of-the-art treatment of MBC depending on disease-associated and biological variables.


Assuntos
Antineoplásicos/uso terapêutico , Neoplasias da Mama/patologia , Neoplasias da Mama/terapia , Ensaios Clínicos como Assunto , Medicina Baseada em Evidências , Feminino , Humanos , Mastectomia , Metanálise como Assunto , Prognóstico
7.
Cancer Treat Rev ; 74: 15-20, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30665053

RESUMO

Progress in and better understanding of cancer biology causes a shift in cancer drug development: away from the evaluation of drugs in large tumour histology defined patient populations towards targeted agents in increasingly heterogeneous molecularly defined subpopulations. This requires novel approaches in clinical trial design by academia and industry, and development of new assessment tools by regulatory authorities. Pharmaceutical industry is developing new targeted agents generating many clinical studies, including target combinations. This requires improved operational efficiency by development of innovative trial designs, strategies for early-stage decision making and early selection of candidate drugs with a high likelihood of success. In addition, patient awareness and ethical considerations necessitate that agents will be rapidly available to patients. Regulatory Authorities such as the European Medicine Agency and national agencies recognise that these changes require a different attitude towards benefit-risk analysis for drug approval. The gold standard of randomised confirmatory Phase III trials is not always ethical or feasible when developing drugs for treatment of small cancer populations. Alternative strategies comprise accelerated approval via conditional marketing approval, which can be granted in the EU based on small non-randomised Phase II trials. The paper describes innovative trial designs with their pros and cons and efforts of pharmaceutical industry and regulatory authorities to deal with the paradigm shift. Furthermore, all stakeholders should continue to share their experiences and discuss problems in order to understand the position and concerns of the other stakeholders to learn from each other and to progress the field of novel oncology clinical trial design.


Assuntos
Ensaios Clínicos como Assunto/métodos , Antineoplásicos , Ensaios Clínicos como Assunto/ética , Ensaios Clínicos como Assunto/normas , Ensaios Clínicos Fase I como Assunto/ética , Ensaios Clínicos Fase I como Assunto/métodos , Ensaios Clínicos Fase I como Assunto/normas , Ensaios Clínicos Fase II como Assunto/ética , Ensaios Clínicos Fase II como Assunto/métodos , Ensaios Clínicos Fase II como Assunto/normas , Ensaios Clínicos Fase III como Assunto/ética , Ensaios Clínicos Fase III como Assunto/métodos , Ensaios Clínicos Fase III como Assunto/normas , Desenvolvimento de Medicamentos , Humanos , Oncologia/ética , Oncologia/métodos , Oncologia/normas , Terapia de Alvo Molecular , Ensaios Clínicos Controlados Aleatórios como Assunto/ética , Ensaios Clínicos Controlados Aleatórios como Assunto/métodos , Ensaios Clínicos Controlados Aleatórios como Assunto/normas
8.
Leukemia ; 19(11): 1929-33, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16151466

RESUMO

In this randomized phase III study of the EORTC Leukemia Cooperative Group, patients with myelodysplastic syndromes (MDS) with 10-30% bone marrow blasts and hematopoietic failure were treated with low-dose cytosine arabinoside (LD-AraC) (2 x 10 mg/m2/day subcutaneously (s.c.) days 1-14) either alone or in combination with rhGM-CSF or interleukin-3 (IL-3) both given s.c. at a dose of 150 microg/day from day 8 to 21. A total of 180 evaluable patients with a median age of 65 years and refractory anemia with an excess of blasts (RAEB, n = 107) or RAEB in transformation (RAEBt, n = 73) were randomized. There were no differences among the three treatment regimens with respect to numbers of courses applied or treatment delays. Hemorrhage occurred in approximately 40% in all arms, whereas infection rates were higher in the granulocyte/macrophage colony stimulating factor (GM-CSF)- or IL3-containing arm. The overall response rate was 38.6% with no statistically significant difference among the three arms. In summary, a substantial proportion of patients had achieved relatively durable responses in all the three arms. No influence of either growth factor was detected on the grade of cytopenia. Thus, the combination of LD-AraC with GM-CSF or IL-3 cannot be recommended for routine use in a high-risk MDS population.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Leucemia/prevenção & controle , Síndromes Mielodisplásicas/tratamento farmacológico , Doença Aguda , Adulto , Idoso , Idoso de 80 Anos ou mais , Citarabina/administração & dosagem , Citarabina/efeitos adversos , Feminino , Fator Estimulador de Colônias de Granulócitos e Macrófagos/administração & dosagem , Fator Estimulador de Colônias de Granulócitos e Macrófagos/efeitos adversos , Humanos , Injeções Subcutâneas , Interleucina-3/administração & dosagem , Interleucina-3/efeitos adversos , Leucemia/etiologia , Masculino , Pessoa de Meia-Idade , Síndromes Mielodisplásicas/complicações , Fatores de Risco , Resultado do Tratamento
9.
Cancer Res ; 44(8): 3336-9, 1984 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-6744267

RESUMO

Treatment of Ehrlich ascites tumor cells with the alkylating agent triaziquone [2,3,5-tris(ethyleneimino)benzoquinone-1,4] and nitrogen mustard leads to a reduction of the posttranslational acetylation of histones. Acetylation of all core histones is affected. The reduction of labeling of acetylated sites is accompanied by a dose-dependent decrease in the extent of acetylation as indicated by the level of acetylation of H4. The depression of histone acetylation is expressed at all concentrations of the alkylating agents which cause significant inhibition of tumor cell proliferation. It could be excluded that the observed effects are caused by an impairment of acetyl coenzyme A synthesis.


Assuntos
Alquilantes , Carcinoma de Ehrlich/metabolismo , Histonas/metabolismo , Mecloretamina/toxicidade , Puromicina/farmacologia , Triaziquona/toxicidade , Acetatos/metabolismo , Ácido Acético , Acetilação , Animais , Histonas/isolamento & purificação , Masculino , Camundongos , Camundongos Endogâmicos , Trítio
10.
Biochim Biophys Acta ; 1358(1): 23-30, 1997 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-9296517

RESUMO

As shown previously, expression of Ha-ras oncogene in NIH 3T3 fibroblasts (+ ras cells) increases cellular concentrations of Ins(1,4,5)P3 and Ins(1,3,4,5)P4 and enhances bradykinin induced Ca2+ entry [1-3]. These cells respond to low concentrations of serum or bradykinin with sustained oscillations of the cell membrane potential due to pulsatile release of calcium from internal stores and subsequent activation of calcium sensitive K+ channels [1]. Furthermore Ha-ras oncogene expression leads to depolymerization of the actin filament network and delayed increase of cell volume [4-6]. Pretreatment of the same cells not expressing the oncogene (-ras cells) with Li+ similarly increases Ins(1,4,5)P3 and Ins(1,3,4,5)P4 [2]. As shown in the present study, -ras cells pretreated with Li+ similar to Ha-ras oncogene expressing cells respond to bradykinin with sustained oscillations of cell membrane potential, depolymerization of the actin filament network and increase of cell volume. The oscillations of the cell membrane potential and the depolymerization of the actin cytoskeleton can be inhibited by the calcium channel blocker lanthanum and the bradykinin induced increase of cell volume is inhibited by HOE 694, pointing to involvement of Na+/H+ exchange. The data indicate a close functional linkage of the calcium oscillations, cytoskeletal rearrangement and activation of the Na+/H+ exchanger. Thus, Li+ pretreatment mimicks crucial cellular events triggered by expression of the Ha-ras oncogene. However, unlike in cells expressing the Ha-ras oncogene, Li+ pretreatment alone does not allow for growth factor-independent proliferation of the cells.


Assuntos
Bradicinina/farmacologia , Genes ras , Lítio/farmacologia , Proteínas ras/metabolismo , Células 3T3/efeitos dos fármacos , Células 3T3/metabolismo , Animais , Divisão Celular , Tamanho Celular/efeitos dos fármacos , Expressão Gênica , Potenciais da Membrana/efeitos dos fármacos , Camundongos
11.
Leukemia ; 13(4): 553-7, 1999 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10214861

RESUMO

Myelodysplastic syndromes (MDS) caused by a clonal hematopoietic stem cell disorder progress to either overt leukemia or cytopenia, which leads to lethal infection or bleeding. Although several clinical trials have attempted to reverse cytopenia by using hematopoietic growth factors (HGF), success has been limited due in part to a limited understanding of the role of HGF in MDS progression. The FLT3 ligand, which binds to and activates the FLT3 receptor, does not have a stimulatory effect on hematopoietic cells, but can synergize with other HGF to support the expansion of both immature and committed progenitors. Using ELISA technology we measured endogenous serum levels in 93 patients with MDS: 29 RA, 1 RARS, 31 RAEB, 23 RAEBt, 9 CMML. 48.3% of RA patients' sera had significantly elevated FLT3 ligand levels ranging from 404 to 5735 pg/ml, whereas none of the RAEB, RAEBt, or CMML patients sera had levels different from controls. No significant correlation was found between FLT3 ligand levels and peripheral blood counts, bone marrow cellularity, age, cytogenetic abnormalities, or survival. Our data suggest that FLT3 ligand levels can be upregulated early in the course of MDS, which may represent an appropriate response to a decreased number of normal progenitors, or alternatively a dysregulated HGF system.


Assuntos
Proteínas de Membrana/sangue , Síndromes Mielodisplásicas/sangue , Adolescente , Adulto , Idoso , Anemia Refratária/sangue , Anemia Refratária/patologia , Anemia Refratária com Excesso de Blastos/sangue , Anemia Refratária com Excesso de Blastos/patologia , Biomarcadores , Biomarcadores Tumorais/sangue , Progressão da Doença , Feminino , Regulação da Expressão Gênica , Hematopoese , Humanos , Leucemia Linfocítica Crônica de Células B/sangue , Leucemia Linfocítica Crônica de Células B/patologia , Masculino , Pessoa de Meia-Idade , Síndromes Mielodisplásicas/complicações , Síndromes Mielodisplásicas/patologia , Proteínas Proto-Oncogênicas/efeitos dos fármacos , Proteínas Proto-Oncogênicas/fisiologia , Receptores Proteína Tirosina Quinases/efeitos dos fármacos , Receptores Proteína Tirosina Quinases/fisiologia , Fator de Células-Tronco/fisiologia , Tirosina Quinase 3 Semelhante a fms
12.
Leukemia ; 12(1): 59-64, 1998 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9436921

RESUMO

Prognosis in patients with myelodysplastic syndromes (MDS) is closely correlated with cytopenia. To date, no factor is available which is able to reliably stimulate megakaryopoiesis in vivo. Recently, the ligand of the mpl receptor was cloned and found to be thrombopoietin (TPO). We measured endogenous TPO serum levels in 69 patients suffering from MDS using an TPO receptor-based ELISA. Twenty-six of the patients suffered from refractory anemia (RA), 12 from RA with excess of blasts (RAEB), 25 from RAEB in transition (RAEBt), and six from chronic myelomonocytic leukemia (CMML). This assay uses a chimeric molecule consisting of the human TPO receptor fused to the Fc portion of human IgG as the capture reagent. Biotinylated antibody to TPO IgG was used for detection and the lower detection limit in serum was found to be 160 pg/ml. Samples obtained from healthy individuals with a normal platelet number were shown to be below detectable levels. In patients with RA, high endogenous serum TPO concentrations correlated with low platelet count and significantly elevated TPO concentrations were only found when megakaryopoiesis was absent or decreased in the bone marrow. This correlation was not detected in RAEB and RAEBt patients and no detectable TPO serum concentrations were found in six CMML patients whether they showed decreased or normal platelet count. Our data show that endogenous TPO production is upregulated by decreased circulating platelet count only in patients with refractory anemia. In the more advanced stages of MDS where the leukemic clone has further progressed, an inadequate TPO response occurs, possibly due to overexpression of the mpl receptor by the malignant clone.


Assuntos
Aberrações Cromossômicas , Leucemia Mielomonocítica Crônica/sangue , Síndromes Mielodisplásicas/sangue , Síndromes Mielodisplásicas/genética , Trombopoetina/sangue , Adulto , Idoso , Idoso de 80 Anos ou mais , Anemia/sangue , Anemia/genética , Anemia/patologia , Células da Medula Óssea/patologia , Deleção Cromossômica , Feminino , Humanos , Leucemia Mielomonocítica Crônica/genética , Leucemia Mielomonocítica Crônica/patologia , Contagem de Leucócitos , Masculino , Megacariócitos/patologia , Pessoa de Meia-Idade , Síndromes Mielodisplásicas/patologia , Contagem de Plaquetas
13.
Leukemia ; 11 Suppl 5: S10-4, 1997 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-9436932

RESUMO

In this study, 25 multiple myeloma (MM) patients at primary diagnosis and 18 MM patients at relapse or progressive disease (PD) were examined in order to investigate the incidence of P-glycoprotein (P-gp) expression at initial diagnosis and relapse or PD. Furthermore, P-gp expression in relation to VAD regimen response was determined. P-gp expression in the myeloma cells was determined using monoclonal antibody 4E3.16 and the rhodamine 123 functional test. The percentage of patients with P-gp overexpression at primary diagnosis ranged between 0 and 41% in the literature vs 32% in our study. The percentage of P-gp positive patients at relapse or PD ranged between 29 and 59% in the literature vs 33% in this analysis. All P-gp positive patients had a functional P-gp, ie a pumping P-gp. A significant difference concerning response (50 vs 58.3%) to VAD treatment and median survival (10 vs 12.5 months) between P-gp positive and P-gp negative patients could not be determined. Six of 12 P-gp negative MM patients at relapse or PD developed after VAD therapy a relapse combined with P-gp overexpression. These results do not confirm the suggestions that P-gp overexpression influences response to VAD treatment. However, the results described in the literature and our own emphasize the need for careful accompanying research programmes aimed at detecting the complexity of chemotherapy resistance in the light of developing a risk-adapting therapy for MM patients.


Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/biossíntese , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Mieloma Múltiplo/patologia , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/análise , Adulto , Idoso , Anticorpos Monoclonais , Proteína de Bence Jones/análise , Proteína C-Reativa/análise , Citarabina/administração & dosagem , Dexametasona/administração & dosagem , Progressão da Doença , Intervalo Livre de Doença , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Pessoa de Meia-Idade , Mieloma Múltiplo/sangue , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/mortalidade , Estadiamento de Neoplasias , Prognóstico , Recidiva , Taxa de Sobrevida , Vincristina/administração & dosagem , Microglobulina beta-2/análise
14.
Leukemia ; 10 Suppl 3: S23-S31, 1996 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-8656697

RESUMO

P-glycoprotein (P-gp) is a crucial factor in the development of chemotherapy resistance in malignant disorders. Between 1989 and 1995, P-gp expression was studied in bone marrow blast cells of 322 (239 AML; 83 ALL) acute leukemia patients. 166 AML patients with the AML-6 protocol (EORTC), containing daunorubicin, vincristine and conventional-dose cytarabine (ara-C), and 63 AML patients treated with intermediate-does Ara-C plus amsacrine. Further 71 ALL patients were treated according to a German standard polychemotherapy protocol (BMFT04/1989). P-gp was determined by using monoclonal antibodies C219 and 4E3, and the cutoff point for P-gp overexpression was set at >/= 10%. A significant (P < 0.06) difference in P-gp overexpression was demonstrated between AML (21.6%) and ALL (10.2%) patients at primary diagnosis and between primary diagnosis and relapse/refractoriness in AML (21.6%; 51.0%) and ALL (10.2%; 27.2%) patients. According to FAB classification P-gp overexpression was detected in AML patients significantly (P < 0.05) more frequently in classes M4, M5a and M5b and less frequently in M3, as compared to other types. For AML patients with P-gp overexpression at primary diagnosis or early relapse/refractoriness, the predictive value for nonresponse to the AML-6 protocol was 91 and 95%, respectively, while late-relapsed AML patients with P-gp overexpression had a significantly (P < 0.05) lower predictive value of 73% for nonresponse. Additionally, in refractory and late-relapsed P-gp--overexpressing AML patients treated with intermediate-dose ara-C plus amsacrine the predictive values for nonresponse were 44 and 39%, respectively, significantly (P < 0.05) lower as compared to AML-6 protocol-treated refractory or late-relapsed AML patients. In P-gp-overexpressing treated ALL patients the predictive values of 50 and 55% for non-response were calculated at primary diagnosis and late relapse, respectively. We conclude that P-gp overexpression is a common phenomenon in AML patients at primary diagnosis or relapse, has an inverse influence on AML-6 treatment outcome and should be taken into consideration in the development of new therapy strategies.


Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/biossíntese , Leucemia/tratamento farmacológico , Leucemia/metabolismo , Doença Aguda , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Resistência a Múltiplos Medicamentos , Resistencia a Medicamentos Antineoplásicos , Regulação Neoplásica da Expressão Gênica , Humanos , Incidência , Leucemia Mieloide/tratamento farmacológico , Leucemia Mieloide/metabolismo , Pessoa de Meia-Idade , Análise Multivariada , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/metabolismo , Valor Preditivo dos Testes , Prognóstico , Recidiva , Fatores de Risco , Células Tumorais Cultivadas , Regulação para Cima
15.
Leukemia ; 8(1): 16-23, 1994 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8289481

RESUMO

In a randomized phase II study, patients with myelodysplastic syndromes (MDS) with 10-30% blasts in the bone marrow and hematopoietic failure were treated with low-dose Ara C (2 x 10 mg/m2 subcutaneously (s.c.) days 1-14) and rhGM-CSF (fully glycosylated, Sandoz/Schering-Plough, 2 x 150 micrograms protein/day s.c.) given either following Ara C (days 15-21) or simultaneously (days 8-14) for 1-5 cycles. 108 patients with a median age of 65 years, range 17-80 years and refractory anemia with an excess of blasts (RAEB, n = 54), RAEB with transformation (RAEBt, n = 50) or with chronic myelomonocytic leukemia (CMML, n = 4) were evaluable. Complete remission was achieved in 15 cases (14%), 11 had a partial response (10%), and 16 a minor response (15%). Stable disease was reached in 35 cases (32%). There were 16 cases of toxic death (15%), progression occurred in 15 patients (14%). No differences existed between the two treatment arms with respect to response and duration of response. Prognostic factors for poor response included the presence of cytogenetic abnormalities and a history of previous blood transfusions. Major adverse events during treatment were hemorrhage (55%), infections (54%), and fever associated with GM-CSF administration (40%). The overall response rate ws 39%, median duration was 12.5 months from start of treatment which allowed responding patients to lead good quality life without further therapy. The question whether the combination is indeed superior to LD-Ara C alone is not settled but will be evaluated in an ongoing clinical trial.


Assuntos
Citarabina/uso terapêutico , Fator Estimulador de Colônias de Granulócitos e Macrófagos/uso terapêutico , Leucemia/etiologia , Síndromes Mielodisplásicas/complicações , Síndromes Mielodisplásicas/tratamento farmacológico , Doença Aguda , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Citarabina/administração & dosagem , Relação Dose-Resposta a Droga , Feminino , Fator Estimulador de Colônias de Granulócitos e Macrófagos/efeitos adversos , Humanos , Leucemia/prevenção & controle , Masculino , Pessoa de Meia-Idade , Proteínas Recombinantes/efeitos adversos , Proteínas Recombinantes/uso terapêutico , Fatores de Risco
16.
Clin Cancer Res ; 2(6): 1031-8, 1996 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9816264

RESUMO

Anemia remains a therapeutic problem in patients with myelodysplastic syndrome (MDS). In view of the recently reported potential of stem cell factor (SCF) in restoring erythropoiesis in combination with erythropoietin (Epo), we first aimed to define a correlation between SCF serum levels and anemia in MDS. Endogenous SCF levels in 50 MDS patients were determined by using a quantitative sandwich enzyme immunoassay. Broad interindividual variations were observed, but SCF serum levels were in the normal range with no correlation to peripheral blood count. A soft agar culture system was used to further define the role of SCF for stimulation of erythroid growth. Bone marrow mononucleated cells of 20 MDS patients (4 refractory anemia, 5 refractory anemia with excess of blasts, 7 refractory anemia with excess of blasts in transition, and 4 chronic myelomonocytic leukemia) were investigated, and SCF plus Epo was able to stimulate burst-forming unit-erythroid significantly more than SCF or Epo alone independent of French-American-British group. When mononucleated cells from six MDS patients (two refractory anemia, two refractory anemia with excess of blasts, and 2 refractory anemia with excess of blasts in transition) with elevated serum Epo levels were incubated in the presence of SCF and autologous serum, a significant dose-dependent stimulation of burst-forming unit-erythroid number and cells per colony was detected. Erythroid differentiation was further enhanced by adding serum with high colony-stimulating activity obtained from patients with severe aplastic anemia. Our data suggest that in MDS patients with high endogenous Epo serum levels SCF alone might be effective in stimulating erythropoiesis in vivo.


Assuntos
Eritropoese/efeitos dos fármacos , Eritropoetina/sangue , Síndromes Mielodisplásicas/tratamento farmacológico , Fator de Células-Tronco/farmacologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Transfusão de Sangue Autóloga , Relação Dose-Resposta a Droga , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Síndromes Mielodisplásicas/sangue , Fator de Células-Tronco/sangue
17.
Eur J Cell Biol ; 72(3): 222-8, 1997 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9084984

RESUMO

Expression of the Ha-ras oncogene in NIH 3T3 fibroblasts (+ras cells) results in growth factor-independent proliferation and marked alteration of cytoskeletal architecture including breakdown of actin stress fiber network. Compared to identical cells not expressing the oncogene (-ras cells), +ras cells exhibit a more alkaline intracellular pH (pHi) and a larger cell volume (CV), both of which are important mitogenic elements. They are due to a set point shift for activation of the Na+/H(+)-exchanger. Moreover +ras cells respond to stimuli like 0.5% fetal calf serum or bradykinin with sustained oscillation of the cell membrane potential (PD) due to stimulated Ca2+ entry which triggers pulsatile release of calcium from internal stores and subsequent activation of calcium-sensitive K+ channels. 10 mumol/l bepridil inhibit oscillations of PD and protect +ras cells against actin stress fiber depolymerization. It is shown that bepridil blocks both cellular calcium entry as measured by Mn2+ quenching of fura-2 fluorescence and activation of the Na+/H(+)-exchanger following expression of the Ha-ras oncogene. Inhibition of the Na+/H(+)-exchange with 10 mumol/l HOE 694, on the other hand, does not significantly alter Ha-ras stimulated calcium entry or cytoskeletal rearrangement. In -ras cells ionomycin (0.1 mumol/l) leads to a transient increase in Cai. This effect is paralleled by a transient depolymerization of actin stress fiber network which cannot be inhibited by HOE 694. Disruption of the actin cytoskeleton in -ras cells by cytochalasin D does not alter steady state cell volume or Na+/ H(+)-exchange activity. However, stimulation of cytochalasin-treated -ras cells with bradykinin leads to cell swelling which can be blunted by HOE 694. The results show that both cytoskeletal rearrangement and activation of the Na+/H(+)-exchanger following expression of the Ha-ras oncogene require stimulated calcium influx and Cai oscillations. The depolymerization of the actin cytoskeleton is permissive for the Na+/ H(+)-exchanger to cause cell swelling upon stimulation with bradykinin.


Assuntos
Actinas/metabolismo , Cálcio/metabolismo , Citoesqueleto/metabolismo , Proteína Oncogênica p21(ras)/metabolismo , Trocadores de Sódio-Hidrogênio/metabolismo , Células 3T3 , Animais , Bradicinina/farmacologia , Tamanho Celular/efeitos dos fármacos , Ativação Enzimática , Concentração de Íons de Hidrogênio , Camundongos
18.
J Invest Dermatol ; 96(6): 932-6, 1991 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-2045682

RESUMO

The myelodysplastic syndromes (MDS) represent clonal disorders of the hematopoietic stem cell that are associated with quantitative and qualitative disturbances of the peripheral blood cells and a high risk for the transition to overt leukemia. As epidermal Langerhans cells (LC) are bone-marrow-derived cells, we were interested to see whether they are altered in patients with MDS. Epidermal sheets were prepared from biopsies taken from the thighs of nine patients with MDS and five control persons and processed for immunoperoxidase staining of CD1a antigens. The density and morphology of CD1a+ cells (i.e., LC) was evaluated by visual assessment as well as automatic image analysis. The density of LC was reduced in seven of nine patients (range, 30-75% of normal), whereas the morphology of LC appeared to be altered in all MDS patients in that the LC displayed large and bizarre cell bodies with only a few and often abnormally long dendrites. The HLA-DR expression by LC was not altered, as shown by double immunofluorescence staining of CD1a and HLA-DR antigens. Ultrastructurally, LC again appeared enlarged and often presented with bizarre nuclei, yet displayed no other abnormalities. Our findings suggest that LC are abnormal in MDS and might even indicate a more wide-spread involvement of the dendritic cell lineage in this syndrome.


Assuntos
Células de Langerhans/patologia , Síndromes Mielodisplásicas/patologia , Humanos , Processamento de Imagem Assistida por Computador , Técnicas Imunoenzimáticas , Células de Langerhans/ultraestrutura , Microscopia , Microscopia Eletrônica
19.
Eur J Cancer ; 38 Suppl 4: S19-23, 2002 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11858959

RESUMO

Early drug development at EORTC has always been subject to structural changes to adapt to the rapid changes that occur in oncological drug development. The expertise of early drug developers has always been cross-fertilised with disease-/tumour-oriented groups and also backwards to the laboratory research groups. This results in the establishment of a solid and dedicated network of medical oncologists with focused expertise in cancer drug development. The EORTC Data Center is fully equipped with all expertise to support clinical research activities and includes regulatory, safety, and quality assurance desks. The EORTC New Drug development Programme (NDDP) provides methodological expertise to early clinical trials and coordinates phase I and phase II studies addressing various approaches. Through NDDP, the early clinical groups and the disease-/tumour-oriented groups have created specific networks to address early drug development in specific tumour types. This results in very efficient networks which have the resources and the patients to address and conduct challenging clinical trials in a standardised fashion ensuring the highest standards in cancer treatment.


Assuntos
Antineoplásicos/uso terapêutico , Agências Internacionais/organização & administração , Oncologia/organização & administração , Neoplasias/tratamento farmacológico , Pesquisa/organização & administração , Ensaios Clínicos como Assunto/métodos , Europa (Continente) , Humanos , Pesquisa/tendências
20.
Br J Pharmacol ; 124(4): 627-38, 1998 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9690853

RESUMO

1. Stimulation of chemotaxis of human polymorphonuclear leucocytes (PMNs) with the chemoattractive peptide fMLP (N-formyl-Met-Leu-Phe) is paralleled by profound morphological and metabolic alterations like changes of intracellular pH (pHi) and cell shape. The present study was performed to investigate the interrelation of cell volume (CV) regulatory ion transport, pHi and migration of fMLP stimulated PMNs. 2. Addition of fMLP to PMNs stimulated directed migration in Boyden chamber assays and was accompanied by rapid initial intracellular acidification and cell swelling. 3. Inhibition of the Na+/H+ exchanger suppressed fMLP stimulated cell migration, accelerated the intracellular acidification and inhibited the fMLP-induced cell swelling. 4. Step omission of extracellular Na+ caused intracellular acidification, which was accelerated by subsequent addition of gastric H+/K+ ATPase inhibitor SCH 28080, or by omission of extracellular K+ ions. In addition Na+ removal caused cell swelling, which was further enhanced by fMLP. 5. H+/K+ATPase inhibitors omeprazole and SCH 28080 inhibited stimulated migration and blunted the fMLP-induced increase in CV. 6. Increasing extracellular osmolarity by addition of mannitol to the extracellular solution caused cell shrinkage followed by regulatory volume increase, partially due to activation of the Na+/H+ exchanger. In fMLP-stimulated cells the CV increase was counteracted by simultaneous addition of mannitol. Under these conditions the fMLP stimulated migration was inhibited. 7. The antibacterial activity of PMNs was not modified by Hoe 694 or omeprazole. 8. Western analysis with a monoclonal anti gastric H+/K+ ATPase beta-subunit antibody detected a glycosylated 35 kD core protein in lysates of mouse and human gastric mucosa as well as in human PMNs. 9. The results indicate that fMLP leads to cell swelling of PMNs due to activation of the Na+/H+ exchanger and a K+-dependent H+-extruding mechanism, presumably an H+/K+ ATPase. Inhibition of these ion transporters suppresses the increase in CV and precludes PMNs from stimulated migration.


Assuntos
Quimiotaxia de Leucócito/efeitos dos fármacos , Mucosa Gástrica/enzimologia , Neutrófilos/efeitos dos fármacos , Inibidores da Bomba de Prótons , Trocadores de Sódio-Hidrogênio/antagonistas & inibidores , Animais , Atividade Bactericida do Sangue/efeitos dos fármacos , Western Blotting , Tamanho Celular/efeitos dos fármacos , Quimiotaxia de Leucócito/fisiologia , Contagem de Colônia Microbiana , Inibidores Enzimáticos/farmacologia , Escherichia coli/crescimento & desenvolvimento , Mucosa Gástrica/citologia , Mucosa Gástrica/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Técnicas In Vitro , Líquido Intracelular/química , Transporte de Íons/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Microscopia Confocal , N-Formilmetionina Leucil-Fenilalanina/farmacologia , Neutrófilos/citologia , Neutrófilos/fisiologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA