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1.
Zhonghua Xue Ye Xue Za Zhi ; 38(12): 1017-1023, 2017 Dec 14.
Artigo em Chinês | MEDLINE | ID: mdl-29365393

RESUMO

Objective: To investigate the efficacy and safety of IA regimen which contains idarubicin (IDA) 8 mg/m(2), 10 mg/m(2) or 12 mg/m(2) as induction chemotherapy for adult patients with de-novo acute myeloid leukemia (AML) . Methods: A total of 1 215 newly diagnosed adult AML patients, ranging from May 2011 to March 2015 in the First Affiliated Hospital of Soochow University and other 36 clinical blood centers in China were enrolled in the multicenter, single-blind, non-randomized, clinical controlled study. To compare the response rate of complete remission (CR) , adverse events between different dose idarubicin combined with cytarabine (100 mg/m(2)) as induction chemotherapy in newly diagnosed patients of adult AML. Results: Of 1 207 evaluable AML patients were assigned to this analysis of CR rate. The CR rates of IDA 8 mg/m(2) group, IDA 10 mg/m(2) group and IDA 12 mg/m(2) group were 73.6% (215/292) , 84.1% (662/787) and 86.7% (111/128) , respectively (P<0.001) . After adjusted for age, blast ratio of bone marrow, FAB classification and risk stratification, the odds ratios (95% CI) of IDA 10 mg/m(2) group and IDA 12 mg/m(2) group were 0.49 (0.34-0.70) and 0.36 (0.18-0.71) , as compared with the IDA 8 mg/m(2) group (P<0.001, P=0.003) . In the intermediate and favorable groups, CR rates was 76.5% (163/213) , 86.9% (506/582) and 86.1% (68/79) in different doses of IDA (P=0.007) . Interestingly, IA regimen with IDA 10 mg/m(2) was the only beneficial factor affecting CR in this group after adjusted for age, blast ratio of bone marrow and FAB classification[OR=0.47 (95% CI 0.31-0.71) , P<0.001]. CR rates in adverse group was 50.0% (18/36) , 60.6% (43/71) and 81.8% (18/22) respectively (P=0.089) . However, the odds ratios (95% CI) of IDA 12 mg/m(2) when compared with the IDA 8 mg/m(2) was 0.22 (0.06-0.80) , after adjusted for age, blast ratio of bone marrow and FAB classification. The median time (days) of neutrophil count less than 0.5×10(9)/L in IDA 8 mg/m(2) group, IDA 10 mg/m(2) group and IDA 12 mg/m(2) group were 14 (11-18) , 15 (11-20) and 18 (14-22) , respectively (P=0.012) and of platelet count lower than 20×10(9)/L were 14 (7-17) , 15 (11-20) and 17 (15-21) , respectively (P=0.001) . The incidences of lung infection in the three groups were 9.8%, 13.5% and 25.2%, respectively (P<0.001) . Conclusions: For young adult patients (aged 18-60 years) with AML in China, intensifying induction therapy with idarubicin 10 mg/m(2) is clinically superior to IDA 8 mg/m(2) and IDA 12 mg/m(2) in favorable intermediate AML subgroup. However, idarubicin 12 mg/m(2) is more suitable to adverse AML subgroup.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Leucemia Mieloide Aguda/tratamento farmacológico , Adolescente , Adulto , China , Citarabina , Humanos , Idarubicina , Pessoa de Meia-Idade , Indução de Remissão , Método Simples-Cego , Resultado do Tratamento , Adulto Jovem
2.
Leukemia ; 29(3): 715-26, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25179733

RESUMO

Multiple myeloma (MM) is incurable in virtually all patients due to the presence of innate and emergent drug-resistance. To identify potential drug resistance mechanisms in MM we used iTRAQ (isobaric tags for relative and absolute quantitation) mass spectrometry to compare protein expression profiles of drug-resistant (RPMI 8226-R5) and sensitive (RPMI 8226-S) isogenic cell lines. We identified selective overexpression of myristoylated alanine-rich C-kinase substrate (MARCKS) in drug-resistant R5 cells. MARCKS overexpression was also observed in several drug-resistant human myeloma cell lines (HMCLs) and in drug-resistant primary MM samples. Functionally, inhibition of MARCKS phosphorylation by enzastaurin or knockdown of the gene by RNAi significantly enhanced the sensitivity of resistant HMCLs and primary MM samples to bortezomib and to other anti-myeloma drugs, providing evidence that MARCKS can modulate drug response. Mechanistically, pMARCKS (phosphorylated form of MARCKS) was found to function as an E2F-1 cofactor to regulate SKP2 transcription. pMARCKS promoted cell-cycle progression by facilitating SKP2 expression, suppressing p27(Kip1) and potentially counteracting drug-induced cell-cycle arrest by promoting Cyclin E/CDK2 activity. Importantly, MARCKS knockdown in combination with bortezomib treatment overcame bortezomib resistance, significantly inhibited tumor growth and prolonged host survival in a MM xenograft model. These data provide a rationale for therapeutic targeting of pMARCKS to improve the outcome of patients with refractory/relapsed MM.


Assuntos
Antineoplásicos/farmacologia , Ácidos Borônicos/farmacologia , Regulação Neoplásica da Expressão Gênica , Peptídeos e Proteínas de Sinalização Intracelular/genética , Proteínas de Membrana/genética , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/genética , Pirazinas/farmacologia , Animais , Bortezomib , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Ciclina E/genética , Ciclina E/metabolismo , Quinase 2 Dependente de Ciclina/genética , Quinase 2 Dependente de Ciclina/metabolismo , Inibidor de Quinase Dependente de Ciclina p27/genética , Inibidor de Quinase Dependente de Ciclina p27/metabolismo , Modelos Animais de Doenças , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/genética , Fator de Transcrição E2F1/genética , Fator de Transcrição E2F1/metabolismo , Humanos , Indóis/farmacologia , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas de Membrana/metabolismo , Camundongos , Mieloma Múltiplo/mortalidade , Mieloma Múltiplo/patologia , Substrato Quinase C Rico em Alanina Miristoilada , Transplante de Neoplasias , Fosforilação , Cultura Primária de Células , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Proteínas Quinases Associadas a Fase S/genética , Proteínas Quinases Associadas a Fase S/metabolismo , Transdução de Sinais , Análise de Sobrevida
3.
Oncogene ; 26(30): 4394-403, 2007 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-17260018

RESUMO

Previously, we reported that the paralogous zinc-finger proteins--CTCF and brother of the regulator of imprinted sites (BORIS), directly contribute to transcriptional regulation of NY-ESO-1 in lung cancer cells. To further examine mechanisms that mediate expression of this cancer-testis gene, we performed software-guided analysis of the NY-ESO-1 promoter region, which revealed several potential Sp1-binding motifs. Sequential 5-aza-2'deoxycytidine/depsipeptide FK228 treatment markedly induced BORIS expression and enhanced nuclear translocation of Sp1 in lung cancer cells. Transient transfection assays using promoter-reporter constructs, as well as gel-shift and chromatin immunoprecipitation experiments revealed that NY-ESO-1 promoter activity coincided with occupancy of the proximal Sp1-binding site in lung cancer cells. Mutations within the Sp1 recognition sequence specifically eliminated binding of Sp1 to this motif in vitro, and markedly diminished NY-ESO-1 promoter activity in vivo. siRNA-mediated inhibition of Sp1 expression decreased NY-ESO-1 promoter activity, whereas knock down of CTCF expression augmented NY-ESO-1 transcription in lung cancer cells. Co-immunoprecipitation experiments indicated that Sp1 physically interacts with BORIS but not with CTCF in vivo. Collectively, these findings suggest that BORIS recruits Sp1 to mediate de-repression of NY-ESO-1 during pulmonary carcinogenesis.


Assuntos
Antígenos de Neoplasias/genética , Proteínas de Ligação a DNA/fisiologia , Regulação Neoplásica da Expressão Gênica , Neoplasias Pulmonares/metabolismo , Proteínas de Membrana/genética , Proteínas Repressoras/fisiologia , Fator de Transcrição Sp1/fisiologia , Antígenos de Neoplasias/análise , Sequência de Bases , Sítios de Ligação , Fator de Ligação a CCCTC , Linhagem Celular Tumoral , Depsipeptídeos/farmacologia , Humanos , Proteínas de Membrana/análise , Dados de Sequência Molecular , Regiões Promotoras Genéticas
4.
Hum Reprod ; 20(7): 1969-74, 2005 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15932910

RESUMO

BACKGROUND: Vitrification is assumed to be a promising method to cryopreserve human oocytes but still needs optimization. In this study, rabbit oocytes (fertilized by ICSI) were vitrified with cryoloops, and the effect of three different cryopreservation protocols on spindle configuration and embryo quality was assessed. METHODS: Metaphase II rabbit oocytes were randomly assigned to one of four groups: (i) control; (ii) E40 [40% ethylene glycol (EG)]; (iii) ED20 [20% EG + 20% dimethylsulphoxide (DMSO)]; and (iv) ED20 + M (20% EG + 20% DMSO + vitrification machine). After warming, one part of each group was fertilized by ICSI to examine the fertilization and embryo cleavage ability, and the others were immunostained for tubulin and chromatin before visualization using confocal microscopy. RESULTS: The survival rates after warming were 79.1, 83.1 and 82.3%, respectively. In protocols E40 and ED20, the spindles were severely injured and the embryo quality not good compared with those in the ED20 + M group. CONCLUSIONS: The fastest cooling rate in combination with EG and DMSO as cryoprotectants had the fewest adverse effects on the spindle configuration of rabbit oocytes and embryo development.


Assuntos
Criopreservação/métodos , Oócitos , Animais , Cromossomos/ultraestrutura , Crioprotetores , Dimetil Sulfóxido , Desenvolvimento Embrionário , Etilenoglicol , Feminino , Humanos , Técnicas In Vitro , Metáfase , Microtúbulos/ultraestrutura , Oócitos/citologia , Coelhos , Injeções de Esperma Intracitoplásmicas , Fuso Acromático/ultraestrutura
5.
Ann Thorac Surg ; 72(2): 371-8; discussion 378-9, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11515869

RESUMO

BACKGROUND: It has previously been demonstrated that 17-allylamino geldanamycin (17-AAG) enhances paclitaxel-mediated cytotoxicity and downregulates vascular endothelial factor expression in non-small cell lung cancer. This project was designed to evaluate the tumoricidal and antiangiogeneic effects of 17-AAG and paclitaxel in H358 non-small cell lung cancer cells grown as xenografts in nude mice. METHODS: In vitro cytotoxic drug combination effects were evaluated by (4, 5-dimethylthiazo-2-yl)-2, 5-diphenyl tetrazolium bromide-based proliferation assays. The combinations of 17-AAG and paclitaxel were administered intraperitoneally in nude mice bearing H358 tumor xenografts. Tumor volumes were measured weekly. Tumor expression of erbB2, vascular endothelial cell growth factor, von Willebrand factor (tumor microvasculature), and activated caspase 3 (apoptosis) were determined by immunohistochemistry. RESULTS: Five- to 22-fold enhancement of paclitaxel cytotoxicity was achieved by paclitaxel + 17-AAG combination that was paralleled with marked induction of apoptosis. This combination treatment profoundly suppressed tumor growth and significantly prolonged survival of mice bearing H358 xenografts. Immunohistochemical staining of tumor tissues indicated profound reduction of vascular endothelial cell growth factor expression associated with reduction of microvasculature in tumors treated with 17-AAG. Apoptotic cells were more abundant in tumors treated with 17-AAG + paclitaxel than in those treated with 17-AAG or paclitaxel alone. CONCLUSIONS: Concurrent exposure of H358 cells to 17-AAG and paclitaxel resulted in supraadditive growth inhibition effects in vitro and in vivo. Analysis of molecular markers of tumor tissues indicated that therapeutic drug levels could be achieved with this chemotherapy regimen leading to significant biological responses. Moreover, 17-AAG-mediated suppression of vascular endothelial cell growth factor production by tumor cells may contribute to the antitumor effects of this drug combination in vivo.


Assuntos
Alilamina/farmacologia , Antibióticos Antineoplásicos/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Carcinoma Pulmonar de Células não Pequenas/patologia , Sobrevivência Celular/efeitos dos fármacos , Neoplasias Pulmonares/patologia , Paclitaxel/farmacologia , Quinonas/farmacologia , Células Tumorais Cultivadas/efeitos dos fármacos , Animais , Apoptose/efeitos dos fármacos , Benzoquinonas , Benzotiazóis , Carcinoma Pulmonar de Células não Pequenas/irrigação sanguínea , Sinergismo Farmacológico , Quimioterapia Combinada , Fatores de Crescimento Endotelial/análise , Humanos , Lactamas Macrocíclicas , Neoplasias Pulmonares/irrigação sanguínea , Linfocinas/análise , Camundongos , Camundongos Nus , Transplante de Neoplasias , Neovascularização Patológica/patologia , Tirfostinas/farmacologia , Fator A de Crescimento do Endotélio Vascular , Fatores de Crescimento do Endotélio Vascular
6.
J Immunother ; 24(2): 151-61, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11265773

RESUMO

Global alterations in chromatin structure profoundly influence gene expression in thoracic neoplasms, silencing tumor suppressors while facilitating the expression of various cancer testis antigens such as NY-ESO-1. Although recent studies have shown that histone deacetylase inhibitors can potentiate tumor suppressor gene induction mediated by demethylating agents in cancer cells, the ability of these agents to augment cancer testis antigen expression have not been fully defined. The authors designed the current study to determine whether the histone deacetylase inhibitor, depsipeptide FR901228 (DP), could enhance NY-ESO-1 induction mediated by the DNA demethylating agent 5-Aza-2'-deoxycytidine (DAC) in cell lines established primarily from thoracic cancers. Quantitative reverse-transcriptase polymerase chain reaction analysis revealed that, under exposure conditions potentially achievable in clinical settings, DAC dramatically induced NY-ESO-1 expression in cultured cancer lines. DP alone mediated negligible target gene induction but significantly augmented DAC-mediated induction of NY-ESO-1. After DAC or sequential DAC-DP treatment, HLA-A*0201 cancer cells were recognized by an HLA-A*0201 CTL specific for NY-ESO-1. Although sequential DAC/DP exposure did not uniformly enhance immune recognition of target cells compared with DAC alone, this treatment mediated profound induction of apoptosis in cancer cells but not normal human bronchial epithelia. The apoptotic effects of DAC, DP, or sequential DAC-DP did not correlate in an obvious manner with histology, or the magnitude of NY-ESO-1 induction in cancer cells. Although the mechanisms have not been fully defined, sequential DAC-DP treatment may be a novel strategy to augment antitumor immunity in cancer patients.


Assuntos
Antibacterianos/uso terapêutico , Antibióticos Antineoplásicos/uso terapêutico , Apoptose/efeitos dos fármacos , Depsipeptídeos , Proteínas de Membrana , Neoplasias/patologia , Peptídeos Cíclicos , Proteínas/imunologia , Linfócitos T Citotóxicos/imunologia , Antibacterianos/farmacologia , Antibióticos Antineoplásicos/farmacologia , Antígenos de Neoplasias/imunologia , Western Blotting , Neoplasias da Mama , Carcinoma Pulmonar de Células não Pequenas , Carcinoma de Células Escamosas , Neoplasias Esofágicas , Citometria de Fluxo , Humanos , Neoplasias Pulmonares , Melanoma , Mesotelioma , Neoplasias/tratamento farmacológico , Neoplasias/imunologia , Neoplasias Pleurais , Proteínas/análise , Células Tumorais Cultivadas
7.
Ann Thorac Surg ; 71(1): 295-301; discussion 301-2, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11216765

RESUMO

BACKGROUND: Although MAGE-3 has been detected in approximately 40% of lung and esophageal cancers, expression of this cancer testis antigen appears to be below the threshold for immune recognition in patients with these malignancies. The aim of this study was to determine if the demethylating agent, 5-Aza-2'-deoxycytidine (DAC) and if the histone deacetylase inhibitor Depsipeptide FR901228 (DP) could enhance MAGE-3 expression in lung and esophageal cancer cells. METHODS: Eleven lung and esophageal cancer lines and cultured normal human bronchial epithelial (NHBE) cells were exposed to normal media (NM), DAC, DP, or combination DAC/DP at varying concentrations and exposure durations. MAGE-3 expression was evaluated by quantitative RT-PCR (TaqMan) and immunohistochemistry techniques. Trypan blue exclusion techniques were used to examine the proliferation of cancer cells after drug exposure. RESULTS: Relative to untreated controls, MAGE-3 expression was enhanced 32-fold (range 3.9 to 110) by DAC alone (0.1 micromol/L x 72 h), 2.1-fold (0.4 to 4.2) by DP alone (25 ng/mL x 6h), and 57-fold (4.6 to 209) by sequential DAC/DP exposure. Increased MAGE-3 mRNA copy numbers coincided with enhanced protein levels in these cells. MAGE-3 expression persisted after drug exposure. Flow cytometry confirmed the presence of functional HLA class I expression in these cells. Sequential DAC/DP treatment mediated pronounced growth inhibition in cancer cells but not NHBE. CONCLUSIONS: Sequential DAC/DP treatment may be a novel strategy to simultaneously augment MAGE-3 expression and induce growth arrest in thoracic malignancies.


Assuntos
Antígenos de Neoplasias/metabolismo , Azacitidina/análogos & derivados , Depsipeptídeos , Neoplasias Esofágicas/metabolismo , Neoplasias Pulmonares/metabolismo , Proteínas de Neoplasias/metabolismo , Peptídeos Cíclicos , Adenocarcinoma/metabolismo , Antibacterianos/farmacologia , Antibióticos Antineoplásicos/farmacologia , Azacitidina/farmacologia , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Metilases de Modificação do DNA/antagonistas & inibidores , Decitabina , Inibidores Enzimáticos/farmacologia , Inibidores de Histona Desacetilases , Humanos , Imuno-Histoquímica , Melanoma/metabolismo , Proteínas de Neoplasias/genética , RNA Mensageiro/análise , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Células Tumorais Cultivadas/efeitos dos fármacos
8.
Cancer Res ; 59(24): 6068-73, 1999 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-10626792

RESUMO

Although SV40 oncoproteins have been detected in malignant pleural mesotheliomas (MPMs), their role in the pathogenesis and clinical behavior of these neoplasms remains controversial. In the present study, we sought to define the relevance of SV40 T/t antigen expression in established human mesothelioma cell lines deficient for p16INK4a as well as ARF expression. SV40 early region sequences were readily detected in genomic DNA isolated from pleural mesothelioma lines; however, levels of SV40 T/t antigen expression were highly variable in these cells. An adenoviral vector expressing an antisense transcript to SV40 early region inhibited T antigen expression and mediated significant growth inhibition and apoptosis in T-antigen-positive mesothelioma cells and SV40-transformed COS-7 cells. Abrogation of T/t antigen expression coincided with enhanced p21/WAF-1 expression, suggesting that restoration of p53-mediated pathways may have contributed to the growth inhibition and apoptosis induced by the antisense construct. These effects were not observed after similar treatment of mesothelioma or lung cancer cells containing no SV40 DNA sequences. Collectively, these data suggest that SV40 oncoproteins contribute to the malignant phenotype of pleural mesotheliomas and indicate that interventions designed to abrogate their expression may be efficacious in the treatment of individuals with these neoplasms.


Assuntos
Antígenos Transformantes de Poliomavirus/genética , Apoptose , Mesotelioma/tratamento farmacológico , Oligonucleotídeos Antissenso/uso terapêutico , Neoplasias Pleurais/tratamento farmacológico , Vírus 40 dos Símios/genética , Adenoviridae/genética , Divisão Celular/efeitos dos fármacos , Técnicas de Transferência de Genes , Genes Precoces , Genes Virais , Vetores Genéticos/genética , Humanos , Mesotelioma/metabolismo , Proteínas Oncogênicas/fisiologia , Fenótipo , Neoplasias Pleurais/metabolismo , Células Tumorais Cultivadas
9.
Clin Cancer Res ; 4(11): 2885-90, 1998 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-9829756

RESUMO

Esophageal adenocarcinoma (SKGT-2, SKGT-4, and SKGT-5) and epidermoid carcinoma (HCE-4) cells containing variable retinoblastoma (Rb), cyclin D1, p16, and p53 expression patterns were exposed to the synthetic flavone, flavopiridol. The IC50 was approximately 100-150 nM for each of these cell lines. Exposure of esophageal carcinoma cells to 300 nM flavopiridol induced cell cycle arrest and apoptosis, resulting in a 90% inhibition of proliferation relative to that of nontreated cells after a 5-day exposure to the drug. Western blot analysis revealed diminution of cyclin D1, Rb, and p107 protein levels after flavopiridol exposure. Whereas cell cycle arrest and overall growth inhibition did not correlate in any obvious manner with the genotype of these cell lines, apoptosis seemed to be more pronounced in SKGT-2 and SKGT-4 cells that lack Rb expression. Pretreatment of esophageal cancer cells with 9-cis-retinoic acid did not substantially potentiate flavopiridol activity in these cell lines. Although the precise mechanism of flavopiridol-mediated cytotoxicity has not been fully defined, this drug is an attractive agent for molecular intervention in esophageal cancers and their precursor lesions; further evaluation of flavopiridol in this clinical context is warranted.


Assuntos
Antineoplásicos/farmacologia , Apoptose , Ciclo Celular/efeitos dos fármacos , Neoplasias Esofágicas/tratamento farmacológico , Flavonoides/farmacologia , Piperidinas/farmacologia , Divisão Celular/efeitos dos fármacos , Humanos , Células Tumorais Cultivadas
10.
Cancer Gene Ther ; 3(6): 357-64, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-8988838

RESUMO

We have been investigating the molecular basis of esophageal carcinogenesis in an attempt to develop gene therapy of established esophageal cancers and premalignant esophageal lesions. In this report we demonstrate the efficacy of adenovirally mediated p16 gene replacement in esophageal squamous cell cancers. Adenoviral p16 efficiently transduced epidermoid cancer cells containing p16 mutations, and expression of exogenous p16 in these cells correlated with G1 cell cycle arrest and profound growth inhibition. No effects were observed in esophageal adenocarcinoma cells due to extremely poor transduction of these cells by adenovirus. These results may have implications regarding the design of clinical trials using p16 gene replacement strategies for intervention in esophageal cancers.


Assuntos
Adenoviridae/genética , Proteínas de Transporte/genética , Divisão Celular/genética , Neoplasias Esofágicas/terapia , Terapia Genética , Adenocarcinoma/metabolismo , Adenocarcinoma/terapia , Western Blotting , Proteínas de Transporte/análise , Proteínas de Transporte/metabolismo , Ciclo Celular/fisiologia , Divisão Celular/efeitos dos fármacos , Ciclina D1 , Inibidor p16 de Quinase Dependente de Ciclina , Ciclinas/análise , Ciclinas/metabolismo , Regulação Neoplásica da Expressão Gênica/genética , Genes Supressores de Tumor/genética , Humanos , Neoplasias Experimentais , Neoplasias de Células Escamosas/metabolismo , Neoplasias de Células Escamosas/terapia , Proteínas Oncogênicas/análise , Proteínas Oncogênicas/metabolismo , Proteína do Retinoblastoma/análise , Proteína do Retinoblastoma/metabolismo , Transdução Genética/genética , Células Tumorais Cultivadas , beta-Galactosidase/genética , beta-Galactosidase/metabolismo
12.
IEEE Trans Neural Netw ; 6(3): 669-77, 1995.
Artigo em Inglês | MEDLINE | ID: mdl-18263352

RESUMO

It has been observed by many authors that the backpropagation (BP) error surfaces usually consist of a large amount of flat regions as well as extremely steep regions. As such, the BP algorithm with a fixed learning rate will have low efficiency. This paper considers dynamic learning rate optimization of the BP algorithm using derivative information. An efficient method of deriving the first and second derivatives of the objective function with respect to the learning rate is explored, which does not involve explicit calculation of second-order derivatives in weight space, but rather uses the information gathered from the forward and backward propagation, Several learning rate optimization approaches are subsequently established based on linear expansion of the actual outputs and line searches with acceptable descent value and Newton-like methods, respectively. Simultaneous determination of the optimal learning rate and momentum is also introduced by showing the equivalence between the momentum version BP and the conjugate gradient method. Since these approaches are constructed by simple manipulations of the obtained derivatives, the computational and storage burden scale with the network size exactly like the standard BP algorithm, and the convergence of the BP algorithm is accelerated with in a remarkable reduction (typically by factor 10 to 50, depending upon network architectures and applications) in the running time for the overall learning process. Numerous computer simulation results are provided to support the present approaches.

13.
IEEE Trans Neural Netw ; 6(5): 1300-3, 1995.
Artigo em Inglês | MEDLINE | ID: mdl-18263424

RESUMO

It is shown that if there are P noncoincident input patterns to learn and a two-layered feedforward neural network having P-1 sigmoidal hidden neuron and one dummy hidden neuron is used for the learning, then any suboptimal equilibrium point of the corresponding error surface is unstable in the sense of Lyapunov. This result leads to a sufficient local minima free condition for the backpropagation learning.

14.
Zhonghua Fu Chan Ke Za Zhi ; 29(12): 706-7, 760, 1994 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-7712894

RESUMO

A case of successful clinical pregnancy after transfer of frozen-thawed embryos was reported in this paper. The woman is a 45,XO karyotype Turner's syndrome patient with primary amenorrhea, and her husband has azospermia. She was given hormone replacement therapy to achieve adequate endometrial development. The donated embryos from two sources were frozen on April 27 and April 30, 1994 respectively. The transfer was done on May 25, 1994. Urinary beta-hCG became positive 14 days later. On July 8th, an intra-uterine embryonic sac containing an embryonic bud with good primitive heart beats was seen under vaginal B-ultrasound. Blood hCG reached 232,900 IU/L on July 25. The pregnancy is going on smoothly. The methods of freezing and thawing embryos were described.


Assuntos
Criopreservação , Transferência Embrionária , Embrião de Mamíferos , Fertilização in vitro , Gravidez , Adulto , Feminino , Humanos
15.
Sheng Li Xue Bao ; 44(5): 502-9, 1992 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-1293766

RESUMO

Two types of plasminogen activator (PAs) are present in human endometrium, and their contents vary with the different phases of menstrual cycle, i.e. high in the proliferative phase and low in the secretory phase. In the present study by immunohistochemical technique, both uPA and tPA antigens were demonstrated in the stromal and glandular cells of the endometrium. In cell culture, tPA was released only from stromal cells and uPA only from glandular cells as determined by SDS-PAGE followed by fibrin overlay technique, but PA inhibitor type-1 (PAI-1) was secreted by both stromal and glandular cells. Furthermore, secretion of PAs from endometrial cells was enhanced by adding estradiol and markedly inhibited by progesterone in a dose dependent manner, while the PAI reacted just in the opposite way. The effect of the peptide hormones, hCG, GnRH, PRL, as well as cAMP in cell culture on the secretion of PAs and PAI was similar to that of estradiol, while forskolin demonstrated definitely more stimulative effect on tPA than uPA. Taking into account of the finding of the present study, it appears that, under hormonal control, a balance between PAs and PAI in the endometrium exists. The physiological roles of the PAs and PAI in the endometrium were discussed.


Assuntos
Endométrio/metabolismo , Inibidor 1 de Ativador de Plasminogênio/metabolismo , Ativadores de Plasminogênio/metabolismo , Adulto , Estradiol/farmacologia , Feminino , Humanos , Pessoa de Meia-Idade , Inibidor 1 de Ativador de Plasminogênio/fisiologia , Progesterona/farmacologia , Ativador de Plasminogênio Tecidual/metabolismo , Ativador de Plasminogênio Tecidual/fisiologia , Ativador de Plasminogênio Tipo Uroquinase/metabolismo , Ativador de Plasminogênio Tipo Uroquinase/fisiologia
16.
Life Sci ; 50(3): 227-33, 1992.
Artigo em Inglês | MEDLINE | ID: mdl-1731175

RESUMO

Platelet G proteins were assessed in 7 normal volunteers before and after 14 days of lithium administration at therapeutic plasma levels. Cholera and pertussis toxin catalyzed ADP-ribosylation of platelet membrane proteins were measured by SDS-PAGE. Immunoblotting with specific antibodies was used to measure platelet membrane alpha i content. There was a statistically significant 37% increase in pertussis toxin mediated ADP-ribosylation of a 40,000 Mr protein in platelet membranes after lithium administration, but cholera toxin mediated ADP-ribosylation of a 45,000 Mr protein and alpha i immunoblotting were unchanged by lithium. Increased pertussis toxin stimulated ADP-ribosylation in the absence of changes in alpha i content could be explained by a shift in platelet Gi in favor of its undissociated, inactive form. This would be consistent with increased platelet adenylyl cyclase activity found in these same subjects after lithium.


Assuntos
Plaquetas/efeitos dos fármacos , Proteínas de Ligação ao GTP/metabolismo , Lítio/farmacologia , Adenosina Difosfato Ribose/metabolismo , Toxina Adenilato Ciclase , Adenilil Ciclases/metabolismo , Adulto , Autorradiografia , Plaquetas/metabolismo , Membrana Celular/efeitos dos fármacos , Toxina da Cólera/farmacologia , Eletroforese em Gel de Poliacrilamida , Feminino , Humanos , Immunoblotting , Lítio/administração & dosagem , Masculino , Peso Molecular , Toxina Pertussis , Fatores de Virulência de Bordetella/farmacologia
17.
Eur J Pharmacol ; 206(2): 159-62, 1991 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-1648502

RESUMO

Incubation of rat glioma C6 cells with 10 microM desipramine for five days in vitro resulted in a 31% reduction of beta-adrenoceptors and a 38% reduction in isoproterenol-stimulated cyclic AMP accumulation. In contrast, forskolin or cholera toxin-stimulated cyclic AMP was unaffected by desipramine. Surprisingly, the beta-adrenoceptor desensitization was accompanied by an increase in the ratio of dissociation constants (KL/KH) for the low and high affinity states of the beta-adrenoceptor respectively and supports the concept of a complex interaction between the receptor and Gs protein.


Assuntos
Desipramina/farmacologia , Receptores Adrenérgicos beta/efeitos dos fármacos , Animais , Toxina da Cólera/farmacologia , Colforsina/farmacologia , AMP Cíclico/metabolismo , Proteínas de Ligação ao GTP/metabolismo , Isoproterenol/farmacologia , Cinética , Receptores Adrenérgicos beta/metabolismo , Células Tumorais Cultivadas/efeitos dos fármacos , Células Tumorais Cultivadas/metabolismo
18.
Psychopharmacol Bull ; 27(3): 199-208, 1991.
Artigo em Inglês | MEDLINE | ID: mdl-1775589

RESUMO

Considerable evidence suggests that signal transduction pathways are targets of lithium (Li) action. A number of investigators have reported that Li attenuates both adenylate cyclase (AC) activity and phosphoinositide (PI) turnover in rodents and in humans, thus "dampening" these systems. We have studied selected components of these second-messenger systems in a series of clinical and preclinical investigations. To overcome confounding effects of alterations in mood state, we examined AC activity and G-protein ribosylation in peripheral blood cells from 10 healthy volunteers, prior to and following 14 days of Li administration. Basal and postreceptor [cesium fluoride (CsF) or Gpp(NH)p] stimulated AC activity were unaffected in lymphocytes. In contrast, both basal and stimulated AC activity in platelets were significantly augmented, compatible with an attenuation of Gi function. Ribosylation of platelet Gs by cholera toxin was unchanged, whereas that of Gi by pertussis toxin (PT) was increased. Given that undissociated G protein is the preferred substrate for PT, our results suggest that Li interferes with subunit dissociation and the subsequent activation of Gi. To determine if Li has similar effects on Gi in the central nervous system, we measured extracellular (EC) cyclic adenosine monophosphate (cAMP) in rat brain by in vivo microdialysis, revealing a dose-dependent increase in cAMP by norepinephrine (NE) antagonized by propranolol. Chronic (4-week) Li doubled basal EC cAMP, while decreasing the fractional response to 100 microM NE. Thus, using in vivo microdialysis, we observed the reported reduction in NE-stimulated AC activity, but only as a function of elevated basal cAMP. Increased basal AC activity has been observed following chronic Li in both humans and rat tissues but generally has not been considered relevant. The PI generating system is another proposed major target for Li that we have studied using an in vitro cell culture model of peripheral blood cells. Chronic (6-day) exposure of neutrophil-like HL60 cells to 1 mM LiCl did not affect agonist fMet-Leu-Phe (fMLP) induced PI turnover. In contrast, Li attenuated both agonist and phorbol ester stimulated Na+/H+ exchange, suggesting reduced protein kinase C (PKC) function. Western blot analysis revealed altered levels of PKC in both membrane and cytosolic fractions. The functional consequences of these complex effects on the two major signal transduction pathways and their interactions in the intact living organism remain to be elucidated.


Assuntos
Química Encefálica/efeitos dos fármacos , Lítio/farmacologia , Transdução de Sinais/efeitos dos fármacos , Adulto , Animais , Plaquetas/efeitos dos fármacos , Plaquetas/metabolismo , Células Cultivadas , Diálise , Feminino , Humanos , Técnicas In Vitro , Masculino , Microquímica , Ratos , Ratos Endogâmicos
19.
Psychopharmacol Bull ; 27(3): 247-53, 1991.
Artigo em Inglês | MEDLINE | ID: mdl-1663633

RESUMO

Chronic treatment with a number of antidepressants results in a down-regulation and/or a desensitization of rat cortical beta-adrenergic receptors (beta ARs). Although these effects generally have been attributed to elevations in intrasynaptic norepinephrine via presynaptic mechanisms, the recent demonstration of similar changes in beta ARs following in vitro incubation of cultured cells with desipramine (DMI) suggests that direct, postsynaptic mechanisms may also be involved. To study these mechanisms, we incubated rat C6 glioma cells with 10 microM DMI for 1 or 5 days. DMI produced a significant reduction in beta AR density following chronic (but not acute) treatment (BMAX control = 1325 +/- 78 fmol/mg; DMI = 1179 +/- 96; p less than .05). Interestingly, the beta AR down-regulation was accompanied by an increase in KL/KH ratio (ratio of dissociation constants for the low- and high-affinity states of the receptor), suggesting that these drugs may stabilize the high-affinity complex. DMI treatment attenuated the cyclic adenosine monophosphate (cAMP) response to 1 microM isoproterenol (control = 540 +/- 82 pmol/mg/15 min; DMI = 335 +/- 64; p less than .05), but not to agents acting distal to the receptor (cholera toxin or forskolin). Coincubation of C6 cells with either the phospholipase A2 (PLA2) inhibitor mepacrine or the protein kinase C (PKC) inhibitor H7, during chronic treatment with DMI, blocked the down-regulation of beta ARs. Incubation of C6 cells with phorbol esters (PKC activators) also down-regulated beta ARs, effects that were nonadditive with those of DMI. Incubation with H7 alone resulted in an up-regulation of beta ARs, consistent with a tonic regulatory effect of PKC on beta ARs.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Desipramina/farmacologia , Fosfolipases A/metabolismo , Proteína Quinase C/metabolismo , Receptores Adrenérgicos beta/efeitos dos fármacos , Animais , Regulação para Baixo , Fosfolipases A2 , Ratos , Células Tumorais Cultivadas/efeitos dos fármacos , Células Tumorais Cultivadas/enzimologia
20.
Chin Med J (Engl) ; 103(10): 851-5, 1990 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-2125259

RESUMO

Different methods of ovum pick-up were used in an IVF program from January 1, 1988 to January 31, 1989. In the initial stage of the program, laparotomy ovum pick-up with surgical treatment of pelvic diseases resulted in two cases of clinical pregnancy in 1987 with full-term delivery of two healthy babies. Transvaginal ovum pick-up with a needle using an ultrasonic endovaginal transducer was started in late 1987. In 1988-1989 the transvaginal method was employed more frequently than laparotomy, and it has become a routine practice in the IVF program. The ultrasonic endovaginal approach seemed to give a low ovum recovery rate (70.99%), but the fertilization rate was high (85.10%, P less than 0.05), and the rate of embryo transfer was 89.33%. The average number of pre-embryo per transfer was 2.26. These figures were quite similar in the two groups. The ultrasonic transvaginal approach for egg retrieval was noninvasive, easily accepted by patients. We suggest that it can be done repeatedly on one patient to improve the cumulative pregnancy rate. However, the laparotomy for ovum pick-up has shown some special merits and is still indicated in some cases.


Assuntos
Fertilização in vitro/métodos , Adulto , Feminino , Humanos , Laparotomia , Folículo Ovariano/diagnóstico por imagem , Ultrassonografia
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