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BACKGROUND: Dupilumab, a human monoclonal anti-interleukin (IL)-4Ra antibody blocks the shared receptor component of IL-4 and IL-13, drivers of type 2 inflammation. Dupilumab is approved for severe/refractory asthma inadequately controlled by existing therapies, but knowledge of its effect on real-world disease burden is lacking. This study investigates real-world effects of dupilumab on asthma exacerbation risk and oral corticosteroid (OCS) use in Japanese individuals with asthma. METHODS: This retrospective, cohort study used a Japanese insurance claims database to identify patients who started dupilumab between 26 March 2019-31 May 2020. Patients were followed for ±365 days from dupilumab initiation. The study primarily assessed the annual incidence rate of severe asthma exacerbations occurring simultaneously with hospitalizations or OCS bursts. Secondary and exploratory endpoints assessed OCS dosage and duration, and healthcare resource utilization (HRU), respectively. RESULTS: At dupilumab initiation (N = 215), mean age was 57.2 years, 41.9% of patients were aged ≥65 years, and 59.5% were female. Dupilumab significantly reduced the annual incidence of severe asthma exacerbations from 1.29 to 0.74 (95% confidence interval, 0.44-0.76) per patient per year. Mean OCS dosage decreased from 10.4 to 7.2 mg/day in chronic OCS users; median frequency of OCS bursts decreased from 3 to 0. Both unscheduled outpatient visits (35.8% vs 29.8%) and hospitalizations (21.9% vs 12.1%) decreased. Mean (standard deviation) duration of hospitalization also decreased from 6.7 (27.6) to 2.2 (8.1) days. CONCLUSIONS: Japanese patients with asthma who received dupilumab had reduced incidence rates of severe asthma exacerbations, OCS use, and HRU over 12 months.
Assuntos
Antiasmáticos , Asma , Humanos , Feminino , Pessoa de Meia-Idade , Masculino , Antiasmáticos/uso terapêutico , Estudos Retrospectivos , Estudos de Coortes , Japão/epidemiologia , Asma/tratamento farmacológico , Asma/epidemiologia , Efeitos Psicossociais da Doença , Corticosteroides/uso terapêuticoRESUMO
BACKGROUND: Safety and efficacy data for dupilumab beyond 1 year are lacking for patients from Japan with moderate-to-severe asthma. METHODS: The TRAVERSE open-label extension (OLE) study (NCT02134028) assessed the safety and efficacy of dupilumab 300 mg every 2 weeks up to 96 weeks in 2282 patients who completed a previous dupilumab asthma study. The primary endpoint was incidence of treatment-emergent adverse events (TEAEs). Secondary endpoints included annualized severe exacerbation rate and change from parent study baseline in pre-bronchodilator forced expiratory volume in 1 second (FEV1), asthma control, quality of life, and blood eosinophil levels. Anti-drug antibodies (ADA) were evaluated. We report results in 160 (7.8% of exposed population) patients recruited from Japanese centers with non-oral corticosteroid (OCS)-dependent asthma rolled over from two parent studies, and in subgroups with a type 2 inflammatory phenotype. RESULTS: TEAEs were consistent with the parent studies and the known safety profile of dupilumab. One patient permanently discontinued treatment due to TEAEs. Exacerbation rates remained low and were sustained to Week 96, as were improvements in pre-bronchodilator FEV1. Rapid, sustained improvements were observed in dupilumab-treated patients who previously received placebo in a parent study, while further improvements in exacerbation rates, asthma control, and asthma-related quality of life were observed in those continuing dupilumab. Blood eosinophil levels decreased progressively while on treatment. Treatment-emergent ADA responses were highest in patients who had previously received placebo. Efficacy results were consistent in patients with a type 2 phenotype. CONCLUSIONS: Long-term dupilumab treatment was well tolerated and efficacious in patients with non-OCS-dependent, moderate-to-severe asthma recruited from Japan. (Funded by Sanofi and Regeneron Pharmaceuticals, Inc.; ClinicalTrials.gov identifier, NCT02134028).
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Antiasmáticos , Asma , Humanos , Corticosteroides/uso terapêutico , Anticorpos Monoclonais/uso terapêutico , Asma/tratamento farmacológico , Asma/induzido quimicamente , Broncodilatadores/uso terapêutico , Método Duplo-Cego , Qualidade de Vida , Resultado do Tratamento , JapãoRESUMO
OBJECTIVES: To identify, describe and summarize evidence on residual symptoms and disease burdens in rheumatoid arthritis (RA) patients qualified as being in remission or low disease activity (LDA). METHODS: A systematic literature review (SLR) was conducted according to Cochrane collaboration guidelines. The population of interest was adult patients with RA in remission or LDA. The reported outcomes of interest were any symptoms or burdens. RESULTS: Fifty-one publications were identified through an eDatabase search. Together with 17 articles found through other sources, 68 were included for full text review. The most commonly reported residual symptoms were pain (number of studies = 25), fatigue (n = 21) and morning stiffness (n = 5). Reported disease burdens included mental health (n = 15), sleep disturbances (n = 7) and work productivity (n = 5), impairment in quality of life (n = 21), and functional disability (n = 34). Substantial residual symptoms and disease burdens were found to be present in patients in remission or LDA. CONCLUSION: This is the first SLR to investigate residual symptoms and disease burdens in RA patients in remission or LDA. The results indicate that despite achieving conventional clinical targets, the disease continues to affect patients, suggesting the existence of unmet need under the current treatment paradigm.
Assuntos
Artrite Reumatoide/diagnóstico , Qualidade de Vida , Adulto , Antirreumáticos/uso terapêutico , Artrite Reumatoide/complicações , Artrite Reumatoide/tratamento farmacológico , Fadiga/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Dor/epidemiologia , Indução de RemissãoRESUMO
OBJECTIVE: To examine patient-reported outcomes (PROs) in patients with different rheumatoid arthritis (RA) disease activity levels and identify residual symptoms. METHODS: Post hoc analyses of overall and Japanese data from two randomized controlled trials including RA patients with previous inadequate responses to methotrexate (NCT01710358) or no/minimal previous disease-modifying antirheumatic drug treatment (NCT01711359) (sponsor: Eli Lilly and Company). Week 24 assessments were disease activity (Simplified Disease Activity Index, Disease Activity Score/Disease Activity Score 28 joints-erythrocyte sedimentation rate) and PROs (pain visual analog scale [VAS], morning joint stiffness [MJS], Health Assessment Questionnaire-Disability Index, Functional Assessment of Chronic Illness Therapy-Fatigue, and Medical Outcomes Study Short Form 36 Health Survey Physical and Mental Component Scores). RESULTS: Patients achieving remission/low disease activity (LDA) at Week 24 had larger/significant improvements from baseline in pain, MJS, disability, fatigue, and physical and emotional quality of life versus patients with high/moderate disease activity. Some patients achieving remission and LDA, reported residual pain (pain VAS >10 mm): 20.8-39.3% and 48.7-70.0% (overall study populations), 16.0-34.5% and 47.1-62.0% (Japanese patients). Residual MJS and fatigue were also reported. CONCLUSION: Remission/LDA were associated with improvements in PROs in overall and Japanese patient populations; however, some patients achieving remission had residual symptoms, including pain.
Assuntos
Antirreumáticos/uso terapêutico , Artrite Reumatoide/tratamento farmacológico , Metotrexato/uso terapêutico , Medidas de Resultados Relatados pelo Paciente , Adulto , Idoso , Antirreumáticos/efeitos adversos , Artrite Reumatoide/epidemiologia , Ensaios Clínicos Fase III como Assunto , Feminino , Humanos , Japão , Masculino , Metotrexato/efeitos adversos , Pessoa de Meia-Idade , Qualidade de Vida , Ensaios Clínicos Controlados Aleatórios como AssuntoRESUMO
Spleen tyrosine kinase (Syk) is associated with Fcγ receptors (FcγRs) and transmits activation signals through FcγRs in myeloid cells. Thus, application of drugs to inhibit Syk activity can affect the development of immune diseases mediated by autoantibodies, while unexpected systemic effects by the inhibition may be concerned because Syk has multiple physiological functions. We used tamoxifen-inducible systemic conditional Syk knockout (KO) mice to evaluate the role of Syk in the pathogenesis of autoimmune arthritis and to investigate the systemic effects of Syk deletion. In a collagen antibody-induced arthritis model, Syk KO mice were almost completely protected from disease induction and showed significantly attenuated accumulation of neutrophils and macrophages in the joints. Syk-deleted macrophages showed less IL-6 and MCP-1 production upon FcγR ligation and exhibited reduced FcγR-mediated phagocytosis in vitro. Syk-deleted macrophages produce more RANTES upon FcγR ligation, indicating a Syk-independent signaling through the FcγR. We further found that both wild-type and Syk-deleted macrophages induced neutrophil chemotaxis upon FcγR ligation in vitro, and air-pouch model demonstrated that Syk-deleted neutrophils have a potential to infiltrate into local tissues in response to collagen and anti-collagen antibodies. However, Syk-deleted neutrophils exhibited greatly decreased neutrophil extracellular traps formation and FcγR-mediated phagocytosis. Our results indicated that Syk deficiency rendered mice completely unresponsive to immune activation by anti-collagen antibodies with disabling one pathway of FcγR-mediated signaling that was crucial for arthritis induction.
Assuntos
Artrite Experimental/imunologia , Autoanticorpos/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Macrófagos/imunologia , Neutrófilos/imunologia , Proteínas Tirosina Quinases/metabolismo , Animais , Autoanticorpos/imunologia , Movimento Celular/genética , Movimento Celular/imunologia , Células Cultivadas , Colágeno/imunologia , Citocinas/genética , Citocinas/metabolismo , Regulação da Expressão Gênica , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Macrófagos/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neutrófilos/efeitos dos fármacos , Fagocitose , Proteínas Tirosina Quinases/genética , Receptores de IgG/metabolismo , Transdução de Sinais/genética , Transdução de Sinais/imunologia , Quinase SykRESUMO
This study compared the time profile of FEV1 after COPD diagnosis among rapid decliners, slow decliners, and sustainers in the year of COPD diagnosis. COPD subjects were identified from the annual medical checkup records of Hitachi, Ltd., employees in Japan (April 1998-March 2019). Subjects were categorized into 3 groups (rapid decliner [decrease of FEV1 ≥ 63 mL/year], slow decliner [< 63 and ≥ 31 mL/year], and sustainer [< 31 mL/year]) for 5 years. The time profile of FEV1 was compared using mixed-effects model for 5 years after diagnosis; risk factors of rapid decliner were detected using logistic model/gradient boosting decision tree. Of 1294 eligible subjects, 18.6%, 25.7%, and 55.7% were classified as rapid decliners, slow decliners, and sustainers, respectively. The annual rates of FEV1 decline were similar 3 years before and until COPD diagnosis. The mean FEV1 in rapid decliners was 2.82 ± 0.04 L in year 0 and 2.41 ± 0.05 L in year 5, and in sustainers, it was 2.67 ± 0.02 L and 2.72 ± 0.02 L (year 0, p = 0.0004). In conclusion, FEV1 declined yearly before diagnosis and the time profiles of FEV1 were different in the 3 groups after COPD diagnosis. Therefore, appropriate treatment of the 3 groups with regular lung function tests is necessary to follow FEV1 decline after COPD onset.
Assuntos
Doença Pulmonar Obstrutiva Crônica , Humanos , Doença Pulmonar Obstrutiva Crônica/diagnóstico , Estudos Retrospectivos , Japão , Volume Expiratório Forçado , Testes de Função Respiratória , PulmãoRESUMO
BACKGROUND: Airflow limitation is a critical physiological feature in chronic obstructive pulmonary disease (COPD), for which long-term exposure to noxious substances, including tobacco smoke, is an established risk. However, not all long-term smokers develop COPD, meaning that other risk factors exist. OBJECTIVE: This study aimed to predict the risk factors for COPD diagnosis using machine learning in an annual medical check-up database. METHODS: In this retrospective observational cohort study (ARTDECO [Analysis of Risk Factors to Detect COPD]), annual medical check-up records for all Hitachi Ltd employees in Japan collected from April 1998 to March 2019 were analyzed. Employees who provided informed consent via an opt-out model were screened and those aged 30 to 75 years without a prior diagnosis of COPD/asthma or a history of cancer were included. The database included clinical measurements (eg, pulmonary function tests) and questionnaire responses. To predict the risk factors for COPD diagnosis within a 3-year period, the Gradient Boosting Decision Tree machine learning (XGBoost) method was applied as a primary approach, with logistic regression as a secondary method. A diagnosis of COPD was made when the ratio of the prebronchodilator forced expiratory volume in 1 second (FEV1) to prebronchodilator forced vital capacity (FVC) was <0.7 during two consecutive examinations. RESULTS: Of the 26,101 individuals screened, 1213 met the exclusion criteria, and thus, 24,815 individuals were included in the analysis. The top 10 predictors for COPD diagnosis were FEV1/FVC, smoking status, allergic symptoms, cough, pack years, hemoglobin A1c, serum albumin, mean corpuscular volume, percent predicted vital capacity, and percent predicted value of FEV1. The areas under the receiver operating characteristic curves of the XGBoost model and the logistic regression model were 0.956 and 0.943, respectively. CONCLUSIONS: Using a machine learning model in this longitudinal database, we identified a number of parameters as risk factors other than smoking exposure or lung function to support general practitioners and occupational health physicians to predict the development of COPD. Further research to confirm our results is warranted, as our analysis involved a database used only in Japan.
RESUMO
We have reported previously that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces apoptosis in the human lymphoblastic T-cell line L-MAT, although these cells do not express the aromatic hydrocarbon receptor (AhR). The AhR-dependent pathway for the induction of immunotoxicity by TCDD has been studied extensively, but the AhR-independent pathway is not understood. Several studies have reported that TCDD elevates the concentration of free intracellular calcium ([Ca(2+)](i)) in various types of cells. However, the precise mechanism of the increase in [Ca(2+)](i) that occurs during apoptosis induced by TCDD has not been elucidated. Upon treatment of L-MAT cells with 20nM TCDD, we observed an early increase in [Ca(2+)](i), within 30min of the addition of TCDD, which was followed by an additional increase at 90min, after which the increase in [Ca(2+)](i) was sustained until 3h after the addition of TCDD. A chelator of intracellular calcium, 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetra(acetoxymethyl ester) (BAPTA-AM), blocked the induction of apoptosis by TCDD in L-MAT cells, but EGTA, a chelator of extracellular calcium, did not. An antagonist of calcium-dependent calmodulin (CaM), W-7, inhibited the induction of apoptosis by TCDD in L-MAT cells. Moreover, W-7 suppressed the mitochondrial release of cytochrome c to the cytosol. These results demonstrate that activated Ca(2+)/CaM could transmit apoptotic signal(s) to mitochondria. The results suggest that Ca(2+)/CaM signals may play an important role in the induction of apoptosis in L-MAT cells by TCDD.
Assuntos
Apoptose/efeitos dos fármacos , Sinalização do Cálcio/efeitos dos fármacos , Calmodulina/metabolismo , Citocromos c/metabolismo , Dibenzodioxinas Policloradas/toxicidade , Linfócitos T/efeitos dos fármacos , Western Blotting , Calmodulina/antagonistas & inibidores , Caspase 3/metabolismo , Fracionamento Celular , Linhagem Celular Tumoral , Quelantes/farmacologia , Fragmentação do DNA/efeitos dos fármacos , Ácido Egtázico/análogos & derivados , Ácido Egtázico/farmacologia , Retículo Endoplasmático/efeitos dos fármacos , Retículo Endoplasmático/metabolismo , Humanos , Receptores de Hidrocarboneto Arílico/metabolismo , Sulfonamidas/farmacologia , Linfócitos T/metabolismo , Linfócitos T/patologiaRESUMO
Zipper-interacting protein kinase (ZIPK) is a widely expressed serine/threonine kinase that has been implicated in cell death and transcriptional regulation, but its mechanism of regulation remains unknown. Here, we identified threonine-265 (Thr265) in ZIPK as a major autophosphorylation site. Mutational analyses revealed that autophosphorylation of Thr265 were essential for its full catalytic activity toward an exogenous substrate as well as for cell death induction. Furthermore, leukemia inhibitory factor (LIF) stimulated Thr265 phosphorylation of ZIPK, thereby leading to phosphorylation and activation of signal transducer and activator of transcription (STAT3). Taken together, our findings demonstrate that ZIPK is positively regulated through Thr265 phosphorylation and that this phosphorylation is essential for its function.
Assuntos
Interleucina-6/fisiologia , MAP Quinase Quinase Quinases/metabolismo , Treonina/metabolismo , Animais , Células HeLa , Humanos , Camundongos , Células NIH 3T3 , Fosforilação , Fator de Transcrição STAT3/metabolismoRESUMO
The overtraining extinction effect (OEE), a phenomenon in which extended training facilitates extinction, has been found in mammals and reptiles. However, fish have never shown OEE. No study has yet investigated OEE in newts, a representative amphibian species. We tested whether newts, Cynops pyrrhogaster, show OEE in a straight-array task. All animals received five trials per day and were given a piece of dried worm during reinforced trials. They showed significant acquisition and extinction effects in reinforced and nonreinforced trials. However, we found no difference in extinction performance between a group with 25-trial acquisition and one with 75-trial acquisition, suggesting that OEE was not found in newts. OEE has generally been explained in terms of frustration-related mechanisms. Our results suggest that emotional reactions to nonreward, such as frustration, may not influence behavior in amphibians.
Assuntos
Extinção Psicológica , Sobreaprendizagem , Salamandridae , Animais , Feminino , Esquema de Reforço , Reforço PsicológicoRESUMO
We have previously reported that protein kinase C (PKC) theta (theta) and protein tyrosine kinase are involved in 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced apoptosis of L-MAT, a human lymphoblastic T cell line. In the current report, we show that Vav1, a GDP/GTP exchange factor for Rho-like small GTPases, could be detected by Western blotting in the membrane fraction of L-MAT cells after TCDD treatment and was precipitated by incubating with an antibody against PKC theta. Furthermore, the degree of phosphorylation of Vav1, which can be detected using the phosphotyrosine-specific antibody PY-20 or 4G10, is significantly increased after treatment with TCDD. In addition, pretreatment of the cells with genistein, a protein tyrosine kinase inhibitor, abolished the phosphorylation of Vav1 and inhibited the apoptosis. These results suggest that TCDD treatment may activate an unidentified protein tyrosine kinase. Accordingly we hypothesize that this kinase phosphorylates Vav1, following which phosphorylated Vav1 may translocate to the membrane with PKC theta. Finally, PKC theta may mediate the transfer of the apoptotic signal to downstream components.
Assuntos
Apoptose/fisiologia , Isoenzimas/metabolismo , Dibenzodioxinas Policloradas/toxicidade , Proteína Quinase C/metabolismo , Proteínas Proto-Oncogênicas c-vav/metabolismo , Linfócitos T/metabolismo , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular Transformada , Humanos , Fosforilação/efeitos dos fármacos , Fosforilação/fisiologia , Proteína Quinase C-theta , Coelhos , Linfócitos T/citologia , Linfócitos T/efeitos dos fármacosRESUMO
Daxx has been shown to play an essential role in type I IFN-mediated suppression of B cell development and apoptosis. Recently, we demonstrated that Tyk2 is directly involved in IFN signaling for the induction and translocation of Daxx, which may result in growth arrest and/or apoptosis of B lymphocyte progenitors. To clarify the molecular mechanisms of how Daxx acts on growth suppression of B lymphocytes, we examined functions of a sumoylation-defective Daxx KA mutant (Daxx K630/631A), which substituted Lys 630 and Lys 631 to Ala. Importantly, Daxx KA localized in the cytoplasm, whereas wild-type Daxx localized in the nucleus. Murine pro-B cell line Ba/F3 expressing Daxx KA revealed a resistance to the IFN-induced growth suppression. It is noteworthy that treatment with an exportin inhibitor, leptomycin B, resulted in nuclear localization of Daxx KA and recovery of the IFN-induced growth suppression in Ba/F3 cells. Moreover, Daxx KA decreased the binding potential to promyelocytic leukemia protein (PML), and overexpression of PML recruited Daxx KA into PML oncogenic domains. Notably, a Daxx-small ubiquitin-related modifier fusion protein exhibited increased nuclear localization and ability to suppress cell growth in Ba/F3 cells. These results demonstrate that the IFN-induced growth suppression of B lymphocytes requires nuclear localization of Daxx through its sumoylation and proper interactions with PML.
Assuntos
Linfócitos B/citologia , Linfócitos B/metabolismo , Proteínas de Transporte/metabolismo , Inibidores do Crescimento/fisiologia , Interferons/fisiologia , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas Nucleares/metabolismo , Receptores de Glucocorticoides/fisiologia , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina/metabolismo , Ativação Transcricional , Transporte Ativo do Núcleo Celular/genética , Alanina/genética , Substituição de Aminoácidos/genética , Animais , Linfócitos B/fisiologia , Proteínas de Transporte/genética , Proteínas de Transporte/fisiologia , Linhagem Celular , Linhagem Celular Tumoral , Proteínas Correpressoras , Citoplasma/genética , Citoplasma/metabolismo , Inibidores do Crescimento/antagonistas & inibidores , Células HeLa , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/fisiologia , Lisina/genética , Camundongos , Chaperonas Moleculares , Proteínas de Neoplasias/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/fisiologia , Proteína da Leucemia Promielocítica , Fatores de Transcrição/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Enzimas de Conjugação de Ubiquitina/fisiologia , Regulação para Cima/fisiologiaRESUMO
Signal transducer and activator of transcription 3 (STAT3) is a latent cytoplasmic transcription factor that can be activated by cytokines and growth factors. It plays important roles in cell growth, apoptosis and cell transformation, and is constitutively active in a variety of tumor cells. In this study, we provide evidence that zipper-interacting protein kinase (ZIPK) interacts physically with STAT3. ZIPK specifically interacted with STAT3, and did not bind to STAT1, STAT4, STAT5a, STAT5b or STAT6. ZIPK phosphorylated STAT3 on serine 727 (Ser727) and enhanced STAT3 transcriptional activity. Small interfering RNA-mediated reduction of ZIPK expression decreased leukemia inhibitory factor (LIF)- and IL-6-induced STAT3-dependent transcription. Furthermore, LIF- and IL-6-mediated STAT3 activation stimulated ZIPK activity. Taken together, our data suggest that ZIPK interacts with STAT3 within the nucleus to regulate the transcriptional activity of STAT3 via phosphorylation of Ser727.
Assuntos
Proteínas Serina-Treonina Quinases/imunologia , Fator de Transcrição STAT3/imunologia , Transdução de Sinais/imunologia , Proteínas Reguladoras de Apoptose , Proteínas Quinases Dependentes de Cálcio-Calmodulina , Linhagem Celular Tumoral , Proteínas Quinases Associadas com Morte Celular , Ativação Enzimática/efeitos dos fármacos , Ativação Enzimática/genética , Ativação Enzimática/imunologia , Humanos , Interleucina-6/farmacologia , Fator Inibidor de Leucemia , Fosforilação/efeitos dos fármacos , Ligação Proteica/genética , Ligação Proteica/imunologia , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Processamento de Proteína Pós-Traducional/genética , Processamento de Proteína Pós-Traducional/imunologia , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Fator de Transcrição STAT3/genética , Fator de Transcrição STAT3/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transcrição Gênica/efeitos dos fármacos , Transcrição Gênica/genética , Transcrição Gênica/imunologiaRESUMO
Interval between acquisition and extinction (A-E interval) was varied in order to investigate effects of regularly alternated partial reinforcement on resistance to extinction and to assess the notion of pattern memory which was suggested on the basis of single alternation study. Random alternation (RA) and double alternation (DA) groups were trained with extensive trials and then extinguished under one-day's (RA1, DA1) or 23-days' (RA23, DA23) A-E interval. RA1 was more resistant to extinction than DA1, but DA23 did not differ from RA23. Moreover, extinction performance of DA schedule was retained well in spite of the extension of A-E interval, unlike that of RA schedule. These extinction results cannot be interpreted consistently even by the N-length variables. The persistence of DA schedule shown in delayed extinction was discussed in terms of the pattern memory assumption.
RESUMO
Thermo-sensitive copolymer consists of poly(2-ethoxyethyl vinyl ether) and poly(hydroxyethyl vinyl ether) (EOVE200-HOVE400), whose sol-gel transition temperature was 20.5 degrees C, was synthesized and its applicability to a drug delivery system was examined. Vitamin E (VE) was enclosed in EOVE200-HOVE400 and the release of VE was measured by varying the temperature 10<-->30 degrees C. There was no release of VE from EOVE200-HOVE400 at 30 degrees C, while VE was released when the temperature was reduced to 10 degrees C.