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1.
Clin Cancer Res ; 29(18): 3633-3640, 2023 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-37406106

RESUMO

PURPOSE: We report updated clinical outcomes from a phase II study of pembrolizumab, trastuzumab, and chemotherapy (PTC) in metastatic esophagogastric cancer in conjunction with outcomes from an independent Memorial Sloan Kettering (MSK) cohort. PATIENTS AND METHODS: The significance of pretreatment 89Zr-trastuzumab PET, plasma circulating tumor DNA (ctDNA) dynamics, and tumor HER2 expression and whole exome sequencing was evaluated to identify prognostic biomarkers and mechanisms of resistance in patients treated on-protocol with PTC. Additional prognostic features were evaluated using a multivariable Cox regression model of trastuzumab-treated MSK patients (n = 226). Single-cell RNA sequencing (scRNA-seq) data from MSK and Samsung were evaluated for mechanisms of therapy resistance. RESULTS: 89Zr-trastuzumab PET, scRNA-seq, and serial ctDNA with CT imaging identified how pre-treatment intrapatient genomic heterogeneity contributes to inferior progression-free survival (PFS). We demonstrated that the presence of intensely avid lesions by 89Zr-trastuzumab PET declines in tumor-matched ctDNA by 3 weeks, and clearance of tumor-matched ctDNA by 9 weeks were minimally invasive biomarkers of durable PFS. Paired pre- and on-treatment scRNA-seq identified rapid clearance of HER2-expressing tumor clones with expansion of clones expressing a transcriptional resistance program, which was associated with MT1H, MT1E, MT2A, and MSMB expression. Among trastuzumab-treated patients at MSK, ERBB2 amplification was associated with improved PFS, while alterations in MYC and CDKN2A/B were associated with inferior PFS. CONCLUSIONS: These findings highlight the clinical relevance of identifying baseline intrapatient heterogeneity and serial ctDNA monitoring of HER2-positive esophagogastric cancer patients to identify early evidence of treatment resistance, which could guide proactive therapy escalation or deescalation.


Assuntos
Neoplasias da Mama , Neoplasias Esofágicas , Neoplasias Gástricas , Humanos , Feminino , Receptor ErbB-2/metabolismo , Receptor de Morte Celular Programada 1/uso terapêutico , Radioisótopos/uso terapêutico , Zircônio , Biomarcadores Tumorais/metabolismo , Neoplasias Esofágicas/tratamento farmacológico , Neoplasias Esofágicas/genética , Neoplasias Esofágicas/induzido quimicamente , Neoplasias Gástricas/tratamento farmacológico , Neoplasias Gástricas/genética , Neoplasias Gástricas/patologia , Trastuzumab/efeitos adversos , Neoplasias da Mama/tratamento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos
2.
J Soc Work (Lond) ; 23(3): 411-427, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-38603438

RESUMO

Summary: The Covid-19 pandemic (Coronavirus) has created complex challenges for recipients of social services worldwide and for the social workers entrusted with assisting them. This article presents a study of the decision-making process of Israeli social workers when coping with ethical and legal dilemmas arising during the pandemic. Method: A qualitative self-administered survey was completed by 478 social workers who worked during the Covid-19 pandemic. Thematic analysis was used to identify major themes. Findings: We identified three major themes. The first theme was concern over the potential violation of the service users' privacy and confidentiality due to the unique circumstances of the pandemic. The second theme was the danger to the social workers' health when serving clients during the pandemic. The third theme focused on difficulties in providing professional services during the pandemic. Applications: We present several recommendations to help social workers cope with ethical and legal decisions in national emergencies.

3.
J Aging Soc Policy ; 33(1): 1-21, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-30895898

RESUMO

In view of the growing need to address the rights of older people as consumers, this study captures the perceptions and meanings that older people attribute to their experiences as older consumers, particularly regarding consumer fraud, using qualitative-phenomenological methodology based on semi-structured, open-ended interviews with 16 older consumers in Israel. The findings raise distinctive aspects of their experiences, including physical and cognitive characteristics of aging, social response to aging, and involvement of family members in decision making and support. The study concludes by offering several sociolegal policy recommendations for protecting older consumers, directed to them, their family members, professionals interacting with them, and the legal system.


Assuntos
Comportamento do Consumidor , Tomada de Decisões , Fraude , Percepção , Populações Vulneráveis/psicologia , Idoso , Idoso de 80 Anos ou mais , Família/psicologia , Feminino , Humanos , Entrevistas como Assunto , Israel , Masculino , Pessoa de Meia-Idade , Pesquisa Qualitativa
4.
Lancet Oncol ; 21(6): 821-831, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32437664

RESUMO

BACKGROUND: Addition of trastuzumab to first-line chemotherapy improves overall survival in patients with HER2-positive metastatic gastric cancer. We assessed the safety and activity of pembrolizumab in combination with trastuzumab and chemotherapy in first-line HER2-positive metastatic oesophagogastric (gastric, oesophageal, or gastroesophageal junction) cancer. METHODS: This study was an investigator-initiated, open-label, non-randomised, single-arm, single centre, phase 2 trial in patients aged 18 years or older with HER2-positive metastatic oesophagogastric cancer. Eligible patients had measurable or evaluable non-measurable disease, Eastern Cooperative Oncology Group performance status of 0, 1, or 2, and left ventricular ejection fraction of at least 53%. Patients were eligible to receive an initial induction cycle of 200 mg flat dose of intravenous pembrolizumab and 8 mg/kg loading dose of intravenous trastuzumab. For subsequent cycles, patients received 130 mg/m2 of intravenous oxaliplatin or 80 mg/m2 of cisplatin on day 1, 850 mg/m2 of oral capecitabine twice a day for 2 weeks followed by 1 week off (or intravenous 5-fluorouracil, 800 mg/m2 per day on days 1-5), and a 200 mg flat dose of intravenous pembrolizumab, and 6 mg/kg of trastuzumab, administered on day 1 of each 3-week cycle. The primary endpoint was 6-month progression-free survival, defined as the proportion of patients alive and free of progression at 6 months, assessed in patients who received at least one dose of trastuzumab and pembrolizumab. The regimen would be considered worthy of further investigation if 26 or more of 37 patients were progression-free at 6 months. This trial is registered with ClinicalTrials.gov, NCT02954536, and is ongoing, but closed to enrolment. FINDINGS: Between Nov 11, 2016, and Jan 23, 2019, 37 patients were enrolled. At the time of data cutoff on Aug 6, 2019, median follow-up among survivors was 13·0 months (IQR 11·7-23·5). The primary endpoint was achieved; 26 (70%; 95% CI 54-83) of 37 patients were progression-free at 6 months. The most common treatment-related adverse event of any grade was neuropathy, which was reported in 36 (97%) of 37 patients. The most common grade 3 or 4 adverse events were lymphocytopenia (seven [19%] patients with grade 3 and two [5%] with grade 4), grade 3 decreased electrolytes (six [16%] patients), and grade 3 anaemia (four [11%] patients). Serious adverse events occurred in two patients patients (both grade 3 nephritis leading to treatment discontinuation). Four patients discontinued pembrolizumab because of immune-related adverse events. There were no treatment-related deaths. INTERPRETATION: Pembrolizumab can be safely combined with trastuzumab and chemotherapy and has promising activity in HER2-positive metastatic oesophagogastric cancer. A randomised phase 3 clinical trial assessing the efficacy and safety of pembrolizumab versus placebo in combination with trastuzumab and chemotherapy in first-line HER2-positive metastatic oesophagogastric cancer is underway. FUNDING: Merck & Co.


Assuntos
Adenocarcinoma/tratamento farmacológico , Anticorpos Monoclonais Humanizados/administração & dosagem , Antineoplásicos Imunológicos/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias Esofágicas/tratamento farmacológico , Junção Esofagogástrica/efeitos dos fármacos , Receptor ErbB-2/antagonistas & inibidores , Neoplasias Gástricas/tratamento farmacológico , Trastuzumab/administração & dosagem , Adenocarcinoma/imunologia , Adenocarcinoma/mortalidade , Adenocarcinoma/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Monoclonais Humanizados/efeitos adversos , Antineoplásicos Imunológicos/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Progressão da Doença , Neoplasias Esofágicas/imunologia , Neoplasias Esofágicas/mortalidade , Neoplasias Esofágicas/patologia , Junção Esofagogástrica/imunologia , Junção Esofagogástrica/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Cidade de Nova Iorque , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Receptor de Morte Celular Programada 1/imunologia , Intervalo Livre de Progressão , Receptor ErbB-2/imunologia , Transdução de Sinais , Neoplasias Gástricas/imunologia , Neoplasias Gástricas/mortalidade , Neoplasias Gástricas/patologia , Fatores de Tempo , Trastuzumab/efeitos adversos , Adulto Jovem
5.
Front Cell Neurosci ; 13: 92, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30918483

RESUMO

Palmitoyl-protein thioesterase 1 (PPT1) is a depalmitoylation enzyme that is mutated in cases of neuronal ceroid lipofuscinosis (NCL). The hallmarks of the disease include progressive neurodegeneration and blindness, as well as seizures. In the current study, we identified 62 high-confident PPT1-binding proteins. These proteins included a self-interaction of PPT1, two V-type ATPases, calcium voltage-gated channels, cytoskeletal proteins and others. Pathway analysis suggested their involvement in seizures and neuronal morphology. We then proceeded to demonstrate that hippocampal neurons from Ppt1-/- mice exhibit structural deficits, and further investigated electrophysiology parameters in the hippocampi of mutant mice, both in brain slices and dissociated postnatal primary cultures. Our studies reveal new mechanistic features involved in the pathophysiology of this devastating neurodegenerative disease.

6.
Pain Res Manag ; 2018: 7257681, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29861805

RESUMO

FMS patients demonstrate an altered profile of chemokines relative to healthy controls (HC). Eotaxin-2 is a potent chemoattractant distributed in a variety of tissues. The aim of the study was to compare serum levels of eotaxin-2 between FMS patients and HC and to examine a potential correlation between eotaxin-2 levels and clinical parameters of FMS. Methods. 50 patients with FMS and 15 HC were recruited. Data on the severity of FMS symptoms and depression were collected. Serum levels of eotaxin-2 (ELISA) were determined in all participants. High-sensitive CRP (hs-CRP) was measured in the FMS group. Results. The FMS cohort included predominantly females (84%), mean age of 49, and mean disease duration of 6 years. FMS patients exhibited significantly higher eotaxin-2 levels (pg/ml) versus HC: 833 (±384) versus 622 (±149), p=0.04. Mean hs-CRP level among FMS patients was 4.8 ± 6 mg/l, a value not indicative of acute inflammation. No correlation was found between eotaxin-2 and hs-CRP levels. No correlation was found between eotaxin-2 and severity measures of FMS or depression. Conclusion. Eotaxin-2 does not appear to be a candidate for a disease activity biomarker in FMS. Further research is warranted into the role of this chemokine in the pathophysiology of the FMS.


Assuntos
Quimiocina CCL24/sangue , Fibromialgia/sangue , Adulto , Proteína C-Reativa/metabolismo , Estudos de Coortes , Feminino , Fibromialgia/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Medição da Dor , Escalas de Graduação Psiquiátrica , Adulto Jovem
7.
Cancer ; 124(7): 1374-1382, 2018 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-29338080

RESUMO

BACKGROUND: A phase 1 trial was used to evaluate a combination of cisplatin, gemcitabine, and escalating doses of veliparib in patients with untreated advanced pancreatic ductal adenocarcinoma (PDAC) in 2 cohorts: a germline BRCA1/2-mutated (BRCA+) cohort and a wild-type BRCA (BRCA-) cohort. The aims were to determine the safety, dose-limiting toxicities (DLTs), maximum tolerated dose, and recommended phase 2 dose (RP2D) of veliparib combined with cisplatin and gemcitabine and to assess the antitumor efficacy (Response Evaluation Criteria in Solid Tumors, version 1.1) and overall survival. METHODS: Gemcitabine and cisplatin were dosed at 600 and 25 mg/m2 , respectively, over 30 minutes on days 3 and 10 of a 21-day cycle. Four dose levels of veliparib were evaluated: 20 (dose level 0), 40 (dose level 1), and 80 mg (dose level 2) given orally twice daily on days 1 to 12 and 80 mg given twice daily on days 1 to 21 (dose level 2A [DL2A]). RESULTS: Seventeen patients were enrolled: 9 BRCA+ patients, 7 BRCA- patients, and 1 patient with an unknown status. DLTs were reached at DL2A (80 mg twice daily on days 1 to 21). Two of the 5 patients in this cohort (40%) experienced grade 4 neutropenia and thrombocytopenia. Two grade 5 events occurred on protocol. The objective response rate in the BRCA+ cohort was 7 of 9 (77.8%). The median overall survival for BRCA+ patients was 23.3 months (95% confidence interval [CI], 3.8-30.2 months). The median overall survival for BRCA- patients was 11 months (95% CI, 1.5-12.1 months). CONCLUSIONS: The RP2D of veliparib was 80 mg by mouth twice daily on days 1 to 12 in combination with cisplatin and gemcitabine; the DLT was myelosuppression. Substantial antitumor activity was seen in BRCA+ PDAC. A randomized phase 2 trial is currently evaluating cisplatin and gemcitabine with and without veliparib for BRCA+ PDAC (NCT01585805). Cancer 2018;124:1374-82. © 2018 American Cancer Society.


Assuntos
Adenocarcinoma/tratamento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Proteína BRCA1/genética , Proteína BRCA2/genética , Carcinoma Ductal Pancreático/tratamento farmacológico , Mutação em Linhagem Germinativa , Neoplasias Pancreáticas/tratamento farmacológico , Adenocarcinoma/genética , Adenocarcinoma/patologia , Adulto , Idoso , Benzimidazóis/administração & dosagem , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/patologia , Cisplatino/administração & dosagem , Estudos de Coortes , Desoxicitidina/administração & dosagem , Desoxicitidina/análogos & derivados , Feminino , Seguimentos , Heterozigoto , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patologia , Prognóstico , Taxa de Sobrevida , Gencitabina , Neoplasias Pancreáticas
8.
Biol Open ; 1(3): 220-31, 2012 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-23213412

RESUMO

Bidirectional transport is a key issue in cellular biology. It requires coordination between microtubule-associated molecular motors that work in opposing directions. The major retrograde and anterograde motors involved in bidirectional transport are cytoplasmic dynein and conventional kinesin, respectively. It is clear that failures in molecular motor activity bear severe consequences, especially in the nervous system. Neuronal migration may be impaired during brain development, and impaired molecular motor activity in the adult is one of the hallmarks of neurodegenerative diseases leading to neuronal cell death. The mechanisms that regulate or coordinate kinesin and dynein activity to generate bidirectional transport of the same cargo are of utmost importance. We examined how Ndel1, a cytoplasmic dynein binding protein, may regulate non-vesicular bidirectional transport. Soluble Ndel1 protein, Ndel1-derived peptides or control proteins were mixed with fluorescent beads, injected into the squid giant axon, and the bead movements were recorded using time-lapse microscopy. Automated tracking allowed for extraction and unbiased analysis of a large data set. Beads moved in both directions with a clear bias to the anterograde direction. Velocities were distributed over a broad range and were typically slower than those associated with fast vesicle transport. Ironically, the main effect of Ndel1 and its derived peptides was an enhancement of anterograde motion. We propose that they may function primarily by inhibition of dynein-dependent resistance, which suggests that both dynein and kinesin motors may remain engaged with microtubules during bidirectional transport.

9.
Cancer ; 118(19): 4795-800, 2012 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-22437754

RESUMO

BACKGROUND: Neuroendocrine tumor (NET) cell lines frequently express both insulin-like growth factor (IGF) ligand and the cognate IGF-1 receptor (IGF-1R) and, as such, potentially depend on the activation of IGF-1R and its downstream effectors for growth and survival. Preclinical studies suggest that somatostatin analogs and mammalian target of rapamycin (mTOR) inhibitors exhibit antitumor activity against NETs through inhibition of IGF-1-dependent signaling, suggesting that IGF-1R inhibition may be a promising therapeutic approach to NETs. Therefore, the authors of this report evaluated the safety and efficacy of MK-0646, a fully human monoclonal antibody (MoAb) that binds to the IGF-1R, as monotherapy in patients with metastatic, well-differentiated NETs. METHODS: A phase 2 study was performed in which patients received intravenous MK-0646 10 mg/kg once weekly over 1 hour. Archived pretreatment tumor tissue was obtained and genotyped for v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS), phosphatidylinositol-3-kinase, catalytic, alpha polypeptide (PIK3CA); and v-raf murine sarcoma viral oncogene homolog B1 (BRAF) mutations, and immunohistochemistry was performed to measure the expression IGF-1R. RESULTS: Twenty-five patients received treatment (40% women; median age, 61 years; age range, 37-83 years), including 15 patients with carcinoid tumors and 10 patients with pancreatic NETs. No partial or complete responses were observed. The median progression-free survival was 4.2 months in the pancreatic NET cohort (range, 0.7-6.7 months) and 2.7 months in the carcinoid cohort (range, 2-3 months). Serious adverse events that were potentially related to MK-0646 included grade 3/4 hyperglycemia in 8 of 25 patients (32%), grade 2 hypersensitivity reaction in 1 of 24 patients (4%), and grade 3 lipase elevation in 1 of 25 patients (4%). CONCLUSIONS: Despite a compelling preclinical rationale, MK-0646 was inactive as a single agent in well-differentiated NETs. Further studies of MK-0646 as a monotherapy in unselected NETs are unwarranted.


Assuntos
Anticorpos Monoclonais/uso terapêutico , Antineoplásicos/uso terapêutico , Tumores Neuroendócrinos/tratamento farmacológico , Receptor IGF Tipo 1/antagonistas & inibidores , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais/efeitos adversos , Anticorpos Monoclonais/farmacologia , Anticorpos Monoclonais Humanizados , Antineoplásicos/administração & dosagem , Antineoplásicos/efeitos adversos , Antineoplásicos/farmacologia , Tumor Carcinoide/tratamento farmacológico , Intervalo Livre de Doença , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Genótipo , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Tumores Neuroendócrinos/patologia , Neoplasias Pancreáticas/tratamento farmacológico , Receptor IGF Tipo 1/metabolismo , Falha de Tratamento
10.
Oncology ; 81(2): 65-72, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21968463

RESUMO

BACKGROUND: S-1 is a novel oral agent combining the 5-fluorouracil (FU) prodrug tegafur with gimeracil and oteracil, which inhibit 5-FU degradation by dihydropyrimidine dehydrogenase and phosphorylation within the gastrointestinal tract, respectively. The study was designed to identify the maximum tolerable dose and the dose-limiting toxicities of two schedules of S-1 combined with oxaliplatin and bevacizumab, in advanced solid tumor patients. METHODS: Schedule A: S-1 was administered orally at 20 mg/m(2) twice daily for 14 consecutive days, escalated by 5 mg/m(2), with fixed-dose intravenous bevacizumab 7.5 mg/kg and oxaliplatin 130 mg/m(2) on day 1 of each 3-week cycle. Schedule B: S-1 was administered at 25 mg/m(2) twice daily for 7 consecutive days, escalated by 5 mg/m(2), with fixed-dose intravenous bevacizumab 5 mg/kg and oxaliplatin 85 mg/m(2) on day 1 of each 2-week cycle. RESULTS: The maximum tolerated dose and recommended phase II dose of S-1 was 25 mg/m(2) twice daily for 14 days for schedule A and 35 mg/m(2) twice daily for 7 days for schedule B. The most common dose-limiting toxicities were grade 3 diarrhea. Both regimens were well tolerated. No pharmacokinetic interactions between oxaliplatin and S-1 components were observed. CONCLUSIONS: S-1, oxaliplatin and bevacizumab can be administered with acceptable safety and tolerability and without evidence of pharmacokinetic interactions.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias/tratamento farmacológico , Administração Oral , Adulto , Idoso , Anticorpos Monoclonais Humanizados/administração & dosagem , Anticorpos Monoclonais Humanizados/farmacocinética , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Bevacizumab , Combinação de Medicamentos , Feminino , Humanos , Masculino , Dose Máxima Tolerável , Pessoa de Meia-Idade , Compostos Organoplatínicos/administração & dosagem , Compostos Organoplatínicos/farmacocinética , Oxaliplatina , Ácido Oxônico/administração & dosagem , Ácido Oxônico/farmacocinética , Tegafur/administração & dosagem , Tegafur/farmacocinética
11.
EMBO J ; 29(1): 107-19, 2010 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-19927128

RESUMO

Regulated activity of the retrograde molecular motor, cytoplasmic dynein, is crucial for multiple biological activities, and failure to regulate this activity can result in neuronal migration retardation or neuronal degeneration. The activity of dynein is controlled by the LIS1-Ndel1-Nde1 protein complex that participates in intracellular transport, mitosis, and neuronal migration. These biological processes are subject to tight multilevel modes of regulation. Palmitoylation is a reversible posttranslational lipid modification, which can dynamically regulate protein trafficking. We found that both Ndel1 and Nde1 undergo palmitoylation in vivo and in transfected cells by specific palmitoylation enzymes. Unpalmitoylated Ndel1 interacts better with dynein, whereas the interaction between Nde1 and cytoplasmic dynein is unaffected by palmitoylation. Furthermore, palmitoylated Ndel1 reduced cytoplasmic dynein activity as judged by Golgi distribution, VSVG and short microtubule trafficking, transport of endogenous Ndel1 and LIS1 from neurite tips to the cell body, retrograde trafficking of dynein puncta, and neuronal migration. Our findings indicate, to the best of our knowledge, for the first time that Ndel1 palmitoylation is a new mean for fine-tuning the activity of the retrograde motor cytoplasmic dynein.


Assuntos
Proteínas de Transporte/química , Proteínas de Transporte/metabolismo , Dineínas/metabolismo , 1-Alquil-2-acetilglicerofosfocolina Esterase/química , 1-Alquil-2-acetilglicerofosfocolina Esterase/metabolismo , Sequência de Aminoácidos , Animais , Sítios de Ligação/genética , Células COS , Proteínas de Transporte/genética , Proteínas de Ciclo Celular/química , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular , Chlorocebus aethiops , Citoplasma/metabolismo , Feminino , Complexo de Golgi/metabolismo , Humanos , Técnicas In Vitro , Lipoilação , Camundongos , Proteínas Associadas aos Microtúbulos/química , Proteínas Associadas aos Microtúbulos/genética , Proteínas Associadas aos Microtúbulos/metabolismo , Microtúbulos/metabolismo , Modelos Biológicos , Dados de Sequência Molecular , Complexos Multiproteicos , Neurônios/metabolismo , Gravidez , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Homologia de Sequência de Aminoácidos , Transfecção
12.
Isr J Psychiatry Relat Sci ; 44(4): 255-65, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-18250514

RESUMO

Sidney J. Blatt's unique contribution to the study of internal representations of parental figures is delineated, and empirical research dealing with interpersonal and intrapersonal aspects of maternal representations in middle childhood is reviewed. Children's representations of mother and father, as well as of an unknown parent, provide evidence of the interconnected effects of actual interpersonal experiences and intrapersonal factors. In addition, new findings related to cultural differences affecting children's maternal representations suggest a broader and more complex perspective for the definition of interpersonal experiences. Taken together, these studies suggest an understanding of an individual's internal world of representations as dialectical transactions between his or her circumstances and rules of organization of interpersonal knowledge, on one hand, and the actual interpersonal experiences and cultural beliefs, on the other. The importance of the study of continuity and change for the understanding of the effects of interpersonal and intrapersonal factors in children's construction of parental representations is underscored.


Assuntos
Relações Interpessoais , Comportamento Materno , Relações Mãe-Filho , Desenvolvimento da Personalidade , Psiquiatria/tendências , Comportamento Social , Adoção , Criança , Feminino , Previsões , Humanos
13.
Nature ; 444(7121): 929-32, 2006 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-17122770

RESUMO

The distribution of fitness effects of protein mutations is still unknown. Of particular interest is whether accumulating deleterious mutations interact, and how the resulting epistatic effects shape the protein's fitness landscape. Here we apply a model system in which bacterial fitness correlates with the enzymatic activity of TEM-1 beta-lactamase (antibiotic degradation). Subjecting TEM-1 to random mutational drift and purifying selection (to purge deleterious mutations) produced changes in its fitness landscape indicative of negative epistasis; that is, the combined deleterious effects of mutations were, on average, larger than expected from the multiplication of their individual effects. As observed in computational systems, negative epistasis was tightly associated with higher tolerance to mutations (robustness). Thus, under a low selection pressure, a large fraction of mutations was initially tolerated (high robustness), but as mutations accumulated, their fitness toll increased, resulting in the observed negative epistasis. These findings, supported by FoldX stability computations of the mutational effects, prompt a new model in which the mutational robustness (or neutrality) observed in proteins, and other biological systems, is due primarily to a stability margin, or threshold, that buffers the deleterious physico-chemical effects of mutations on fitness. Threshold robustness is inherently epistatic-once the stability threshold is exhausted, the deleterious effects of mutations become fully pronounced, thereby making proteins far less robust than generally assumed.


Assuntos
Epistasia Genética , beta-Lactamases/genética , beta-Lactamases/metabolismo , Escherichia coli/enzimologia , Escherichia coli/genética , Deriva Genética , Mutação/genética , Seleção Genética , beta-Lactamases/química
14.
J Cell Sci ; 118(Pt 14): 3163-71, 2005 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-15985466

RESUMO

The Sf9 cell line, derived from the moth Spodoptera frugiperda, is highly and specifically sensitive to the Bacillus thuringiensis Cry1C toxin. Upon exposure to Cry1C, ionic pores are formed in the plasma membrane leading to cell swelling and death. Here, we describe a unique transient tolerance to Cry1C of dividing cells, which allowed completion of the division process in the presence of Cry1C. Correlatively, arresting the cells at G2-M phase by nocodazole treatment rendered them insensitive to Cry1C. When the arresting agent was removed, the cells completed their division and gradually regained Cry1C sensitivity. In comparison to normal cells with 1-2% cell-division frequency, the M-phase arrested cells bound less toxin in binding assays. Moreover, no lipid rafts could be isolated from the membranes of M-phase arrested cells. Caveolin-1, identified here for the first time in insect cells, was immunodetected as a lipid raft component of normal cells, but was only present in the membrane-soluble fraction of G2-M-arrested cells. Thus M-phase-linked changes in lipid raft organization may account for diminished Cry1C binding and toxicity. Furthermore, considering the pivotal role of lipid rafts in different cell functions of many cell types, the lack of organized lipid rafts in dividing cells may transiently affect cell susceptibility to pathogens, toxins and other lipid raft-linked functions.


Assuntos
Proteínas de Bactérias/farmacologia , Toxinas Bacterianas/farmacologia , Endotoxinas/farmacologia , Inseticidas/farmacologia , Microdomínios da Membrana/metabolismo , Spodoptera/metabolismo , Animais , Bacillus thuringiensis/química , Toxinas de Bacillus thuringiensis , Proteínas de Bactérias/metabolismo , Toxinas Bacterianas/metabolismo , Western Blotting , Divisão Celular/efeitos dos fármacos , Divisão Celular/fisiologia , Células Cultivadas , Endotoxinas/metabolismo , Fase G1/efeitos dos fármacos , Fase G1/fisiologia , Fase G2/efeitos dos fármacos , Fase G2/fisiologia , Proteínas Hemolisinas , Resistência a Inseticidas , Inseticidas/metabolismo , Mitose/efeitos dos fármacos , Spodoptera/citologia
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