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1.
JCI Insight ; 9(13)2024 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-38781563

RESUMO

Prenatal exposure to viral pathogens has been known to cause the development of neuropsychiatric disorders in adulthood. Furthermore, COVID-19 has been associated with a variety of neurological manifestations, raising the question of whether in utero SARS-CoV-2 exposure can affect neurodevelopment, resulting in long-lasting behavioral and cognitive deficits. Using a human ACE2-knock-in mouse model, we have previously shown that prenatal exposure to SARS-CoV-2 at later stages of development leads to fetal brain infection and gliosis in the hippocampus and cortex. In this study, we aimed to determine whether infection of the fetal brain results in long-term neuroanatomical alterations of the cortex and hippocampus or in any cognitive deficits in adulthood. Here, we show that infected mice developed slower and weighed less in adulthood. We also found altered hippocampal and amygdala volume and aberrant newborn neuron morphology in the hippocampus of adult mice infected in utero. Furthermore, we observed sex-dependent alterations in anxiety-like behavior and locomotion, as well as hippocampal-dependent spatial memory. Taken together, our study reveals long-lasting neurological and cognitive changes as a result of prenatal SARS-CoV-2 infection, identifying a window for early intervention and highlighting the importance of immunization and antiviral intervention in pregnant women.


Assuntos
COVID-19 , Modelos Animais de Doenças , Hipocampo , Complicações Infecciosas na Gravidez , Efeitos Tardios da Exposição Pré-Natal , SARS-CoV-2 , Animais , Feminino , Gravidez , Camundongos , Efeitos Tardios da Exposição Pré-Natal/virologia , Hipocampo/patologia , Complicações Infecciosas na Gravidez/virologia , Complicações Infecciosas na Gravidez/patologia , Masculino , Comportamento Animal , Humanos , Ansiedade , Enzima de Conversão de Angiotensina 2/metabolismo , Neurônios/patologia , Neurônios/virologia , Transtornos do Neurodesenvolvimento/virologia
2.
Stem Cell Reports ; 18(7): 1516-1533, 2023 07 11.
Artigo em Inglês | MEDLINE | ID: mdl-37352850

RESUMO

Alzheimer's disease (AD) is the most common neurodegenerative disorder, but its root cause may lie in neurodevelopment. PSEN1 mutations cause the majority of familial AD, potentially by disrupting proper Notch signaling, causing early unnoticed cellular changes that affect later AD progression. While rodent models are useful for modeling later stages of AD, human induced pluripotent stem cell-derived cortical spheroids (hCSs) allow access to studying the human cortex at the cellular level over the course of development. Here, we show that the PSEN1 L435F heterozygous mutation affects hCS development, increasing size, increasing progenitors, and decreasing post-mitotic neurons as a result of increased Notch target gene expression during early hCS development. We also show altered Aß expression and neuronal activity at later hCS stages. These results contrast previous findings, showing how individual PSEN1 mutations may differentially affect neurodevelopment and may give insight into fAD progression to provide earlier time points for more effective treatments.


Assuntos
Doença de Alzheimer , Células-Tronco Pluripotentes Induzidas , Humanos , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Células-Tronco Pluripotentes Induzidas/metabolismo , Mutação , Neurônios/metabolismo , Presenilina-1/genética , Presenilina-1/metabolismo
3.
Pharmacol Biochem Behav ; 202: 173115, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33493546

RESUMO

Selective serotonin transport (SERT) inhibitors such as fluoxetine are the most commonly prescribed treatments for depression. Although efficacious for many symptoms of depression, motivational impairments such as psychomotor retardation, anergia, fatigue and amotivation are relatively resistant to treatment with SERT inhibitors, and these drugs have been reported to exacerbate motivational deficits in some people. In order to study motivational dysfunctions in animal models, procedures have been developed to measure effort-related decision making, which offer animals a choice between high effort actions leading to highly valued reinforcers, or low effort/low reward options. In the present studies, male and female rats were tested on two different tests of effort-based choice: a fixed ratio 5 (FR5)/chow feeding choice procedure and a running wheel (RW)/chow feeding choice task. The baseline pattern of choice differed across tasks for males and females, with males pressing the lever more than females on the operant task, and females running more than males on the RW task. Administration of the SERT inhibitor and antidepressant fluoxetine suppressed the higher effort activity on each task (lever pressing and wheel running) in both males and females. The serotonin receptor mediating the suppressive effects of fluoxetine is uncertain, because serotonin antagonists with different patterns of receptor selectivity failed to reverse the effects of fluoxetine. Nevertheless, these studies uncovered important sex differences, and demonstrated that the suppressive effects of fluoxetine on high effort activities are not limited to tasks involving food reinforced behavior or appetite suppressive effects. It is possible that this line of research will contribute to an understanding of the neurochemical factors regulating selection of voluntary physical activity vs. sedentary behaviors, which could be relevant for understanding the role of physical activity in psychiatric disorders.


Assuntos
Antidepressivos/administração & dosagem , Comportamento de Escolha/efeitos dos fármacos , Comportamento Alimentar/efeitos dos fármacos , Fluoxetina/administração & dosagem , Atividade Motora/efeitos dos fármacos , Inibidores Seletivos de Recaptação de Serotonina/administração & dosagem , Animais , Feminino , Masculino , Ratos , Ratos Sprague-Dawley , Reforço Psicológico , Recompensa , Antagonistas do Receptor 5-HT2 de Serotonina/administração & dosagem , Fatores Sexuais
4.
BMC Public Health ; 19(1): 1451, 2019 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-31684909

RESUMO

BACKGROUND: Adolescent alcohol consumption is an issue of ongoing concern and programs targeting parents have been identified as an important component in minimizing and preventing alcohol related harm in adolescents. This paper aims to evaluate existing parent based alcohol education programs with a focus on understanding parent specific outcomes including parental attitudes, parent-child communication, alcohol specific rule setting and parental monitoring; study quality, the extent of stakeholder engagement in program design and the level of theory application. METHOD: A systematic review of electronic databases EBSCO, Emerald, ProQuest, PubMed, Ovid, ScienceDirect, Taylor and Francis and Web of Science was conducted from database inception to August 2019. A total of 4288 unique records were retrieved from the eight databases. Studies were included if they evaluated school based alcohol education programs that included a parent component and detailed outcome measures associated with parent data. The methodological quality of the included studies was assessed using the Effective Public Health Practice Project (EPHPP) quality assessment tool. RESULTS: In total 17 studies qualified for assessment, detailing 13 individual parent programs. Of these, ten programs demonstrated positive effects in at least one parent reported outcome measure. Stakeholder engagement during the design of programs was lacking with the majority of programs. One third of the programs did not report theory use and when theory was used reporting was weak with three programs applying theory, five testing theory and none building theory. According to the EPHPP tool, overall ten programs were rated as weak, three as moderate and none as strong. CONCLUSION: Future studies are recommended to further enhance the effectiveness of parental programs by improving study quality, increasing stakeholder engagement and increasing the level of theory application and reporting.


Assuntos
Consumo de Bebidas Alcoólicas/prevenção & controle , Educação em Saúde , Pais/educação , Adolescente , Humanos , Relações Pais-Filho , Pais/psicologia , Avaliação de Programas e Projetos de Saúde , Ensaios Clínicos Controlados Aleatórios como Assunto
5.
Gastroenterology ; 157(1): 210-226.e12, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30878468

RESUMO

BACKGROUND & AIMS: The CCNE1 locus, which encodes cyclin E1, is amplified in many types of cancer cells and is activated in hepatocellular carcinomas (HCCs) from patients infected with hepatitis B virus or adeno-associated virus type 2, due to integration of the virus nearby. We investigated cell-cycle and oncogenic effects of cyclin E1 overexpression in tissues of mice. METHODS: We generated mice with doxycycline-inducible expression of Ccne1 (Ccne1T mice) and activated overexpression of cyclin E1 from age 3 weeks onward. At 14 months of age, livers were collected from mice that overexpress cyclin E1 and nontransgenic mice (controls) and analyzed for tumor burden and by histology. Mouse embryonic fibroblasts (MEFs) and hepatocytes from Ccne1T and control mice were analyzed to determine the extent to which cyclin E1 overexpression perturbs S-phase entry, DNA replication, and numbers and structures of chromosomes. Tissues from 4-month-old Ccne1T and control mice (at that age were free of tumors) were analyzed for chromosome alterations, to investigate the mechanisms by which cyclin E1 predisposes hepatocytes to transformation. RESULTS: Ccne1T mice developed more hepatocellular adenomas and HCCs than control mice. Tumors developed only in livers of Ccne1T mice, despite high levels of cyclin E1 in other tissues. Ccne1T MEFs had defects that promoted chromosome missegregation and aneuploidy, including incomplete replication of DNA, centrosome amplification, and formation of nonperpendicular mitotic spindles. Whereas Ccne1T mice accumulated near-diploid aneuploid cells in multiple tissues and organs, polyploidization was observed only in hepatocytes, with losses and gains of whole chromosomes, DNA damage, and oxidative stress. CONCLUSIONS: Livers, but not other tissues of mice with inducible overexpression of cyclin E1, develop tumors. More hepatocytes from the cyclin E1-overexpressing mice were polyploid than from control mice, and had losses or gains of whole chromosomes, DNA damage, and oxidative stress; all of these have been observed in human HCC cells. The increased risk of HCC in patients with hepatitis B virus or adeno-associated virus type 2 infection might involve activation of cyclin E1 and its effects on chromosomes and genomes of liver cells.


Assuntos
Adenoma de Células Hepáticas/genética , Carcinoma Hepatocelular/genética , Instabilidade Cromossômica/genética , Ciclina E/genética , Neoplasias Hepáticas/genética , Fígado/metabolismo , Proteínas Oncogênicas/genética , Adenoma de Células Hepáticas/patologia , Adenoma de Células Hepáticas/virologia , Animais , Carcinoma Hepatocelular/patologia , Carcinoma Hepatocelular/virologia , Estruturas Cromossômicas , Dano ao DNA/genética , Replicação do DNA , Dependovirus , Fibroblastos , Hepatite B Crônica , Hepatócitos , Fígado/patologia , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/virologia , Neoplasias Hepáticas Experimentais/genética , Neoplasias Hepáticas Experimentais/patologia , Camundongos , Estresse Oxidativo/genética , Infecções por Parvoviridae , Parvovirinae , Poliploidia , Pontos de Checagem da Fase S do Ciclo Celular
6.
Am J Speech Lang Pathol ; 28(1S): 330-340, 2019 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-30054625

RESUMO

Purpose The Story Goodness Index (SGI) is a hybrid analysis of narrative discourse combining 2 macrostructural measures: story grammar and story completeness. Initially proposed by Lê and colleagues ( Lê, Coelho, Mozeiko, & Grafman, 2011 ), the SGI is intended to characterize the discourse performance of individuals with cognitive-communication disorders. In this study, the SGI was utilized to examine the discourse of 2 groups, one with closed head injuries and another with non-brain injured (NBI) peers. The intent of this study was to ascertain whether the SGI could differentiate the discourse performance of the 2 groups, as was previously reported for individuals with penetrating traumatic brain injury and an NBI comparison group ( Lê, Coelho, Mozeiko, Krueger, & Grafman, 2012 ). Because of the retrospective nature of this study, the wordless visual narrative used to elicit discourse was different from the narrative used by Lê and colleagues (2012) . Method A retrospective analysis of discourse was performed on 55 individuals with a history of closed head injury and 47 NBI socioeconomically matched peers. During the initial assessment, participants were engaged in a narrative retell task. Each participant was shown a wordless picture story and then asked to retell the story to the examiner. Story narratives were reanalyzed for story grammar (organization) and completeness (critical content). Results A significant group difference was noted for the story grammar measure, but not for story completeness. Although the SGI plots depicted the heterogeneity in discourse performance of the 2 groups, a chi-square test of independence revealed no significant association between group membership and SGI quadrant. Conclusions Findings from this study were inconsistent with those of Lê and colleagues. The studies did not use identical SGI protocols; specifically, different picture stimuli were used to elicit the story retells. Therefore, this study cannot be considered a replication. The story used by Lê and colleagues was judged to be more complex, requiring more inference for story interpretation. Future studies should interpret findings within the context of the story stimuli presented.


Assuntos
Lesões Encefálicas Traumáticas/psicologia , Transtornos da Comunicação/etiologia , Narração , Adolescente , Adulto , Idoso , Estudos de Casos e Controles , Transtornos Cognitivos/diagnóstico , Transtornos Cognitivos/etiologia , Transtornos da Comunicação/diagnóstico , Feminino , Seguimentos , Humanos , Transtornos da Linguagem/diagnóstico , Transtornos da Linguagem/etiologia , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Estimulação Luminosa/métodos , Estudos Retrospectivos , Medida da Produção da Fala/métodos , Adulto Jovem
7.
J Res Pract ; 14(1)2018.
Artigo em Inglês | MEDLINE | ID: mdl-30057632

RESUMO

We report on the implementation experience of carrying out data collection and other activities for a public health evaluation study on whether U.S. President's Emergency Plan for AIDS Relief (PEPFAR) investment improved utilization of health services and health system strengthening in Uganda. The retrospective study period focused on the PEPFAR scale-up, from mid-2005 through mid-2011, a period of expansion of PEPFAR programing and health services. We visited 315 health care facilities in Uganda in 2011 and 2012 to collect routine health management information system data forms, as well as to conduct interviews with health system leaders. An earlier phase of this research project collected data from all 112 health district headquarters, reported elsewhere. This article describes the lessons learned from collecting data from health care facilities, project management, useful technologies, and mistakes. We used several new technologies to facilitate data collection, including portable document scanners, smartphones, and web-based data collection, along with older but reliable technologies such as car batteries for power, folding tables to create space, and letters of introduction from appropriate authorities to create entrée. Research in limited-resource settings requires an approach that values the skills and talents of local people, institutions and government agencies, and a tolerance for the unexpected. The development of personal relationships was key to the success of the project. We observed that capacity building activities were repaid many fold, especially in data management and technology.

8.
Health Policy Plan ; 31(7): 897-909, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27017824

RESUMO

OBJECTIVES : PEPFAR's initial rapid scale-up approach was largely a vertical effort focused fairly exclusively on AIDS. The purpose of our research was to identify spill-over health system effects, if any, of investments intended to stem the HIV epidemic over a 6-year period with evidence from Uganda. The test of whether there were health system expansions (aside from direct HIV programming) was evidence of increases in utilization of non-HIV services-such as outpatient visits, in-facility births or immunizations-that could be associated with varying levels of PEPFAR investments at the district level. METHODS : Uganda's Health Management Information System article-based records were available from mid-2005 onwards. We visited all 112 District Health offices to collect routine monthly reports (which contain data aggregated from monthly facility reports) and annual reports (which contain data aggregated from annual facility reports). Counts of individuals on anti-retroviral therapy (ART) at year-end served as our primary predictor variable. We grouped district-months into tertiles of high, medium or low PEPFAR investment based on their total reported number of patients on ART at the end of the year. We generated incidence-rate ratios, interpreted as the relative rate of the outcome measure in relation to the lowest investment PEPFAR tertile, holding constant control variables in the model. RESULTS : We found PEPFAR investment overall was associated with small declines in service volumes in several key areas of non-HIV care (outpatient care for young children, TB tests and in-facility deliveries), after adjusting for sanitation, elementary education and HIV prevalence. For example, districts with medium and high ART investment had 11% fewer outpatient visits for children aged 4 and younger compared with low investment districts, incidence rate ratio (IRR) of 0.89 for high investment compared with low (95% CI, 0.85-0.94) and IRR of 0.93 for medium compared with low (0.90-0.96). Similarly, 22% fewer TB sputum tests were performed in high investment districts compared with low investment, [IRR 0.78 (0.72-0.85)] and 13% fewer in medium compared with low, [IRR 0.88 (0.83-0.94)]. Districts with medium and high ART investment had 5% fewer in-facility deliveries compared with low investment districts [IRR 0.95 for high compared with low, (91-1.00) and 0.96 for medium compared with low (0.93-0.99)]. Although not statistically significant, the rate of maternal deaths in high investment district-months was 13% lower than observed in low investment districts. CONCLUSIONS : This study sought to understand whether PEPFAR, as a vertical programme, may have had a spill-over effect on the health system generally, as measured by utilization. Our conclusion is that it did not, at least not in Uganda.


Assuntos
Atenção à Saúde/organização & administração , Apoio Financeiro , Serviços de Saúde/estatística & dados numéricos , Cooperação Internacional , Saúde Global , Infecções por HIV/tratamento farmacológico , Humanos , Estudos Retrospectivos , Uganda
9.
PLoS One ; 11(2): e0146720, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26914708

RESUMO

Achieving an AIDS-free generation will require the adoption and implementation of critical health policy reforms. However, countries with high HIV burden often have low policy development, advocacy, and monitoring capacity. This lack of capacity may be a significant barrier to achieving the AIDS-free generation goals. This manuscript describes the increased focus on policy development and implementation by the United States President's Emergency Plan for AIDS Relief (PEPFAR). It evaluates the curriculum and learning modalities used for two regional policy capacity building workshops organized around the PEPFAR Partnership Framework agreements and the Road Map for Monitoring and Implementing Policy Reforms. A total of 64 participants representing the U.S. Government, partner country governments, and civil society organizations attended the workshops. On average, participants responded that their policy monitoring skills improved and that they felt they were better prepared to monitor policy reforms three months after the workshop. When followed-up regarding utilization of the Road Map action plan, responses were mixed. Reasons cited for not making progress included an inability to meet or a lack of time, personnel, or governmental support. This lack of progress may point to a need for building policy monitoring systems in high HIV burden countries. Because the success of policy reforms cannot be measured by the mere adoption of written policy documents, monitoring the implementation of policy reforms and evaluating their public health impact is essential. In many high HIV burden countries, policy development and monitoring capacity remains weak. This lack of capacity could hinder efforts to achieve the ambitious AIDS-free generation treatment, care and prevention goals. The Road Map appears to be a useful tool for strengthening these critical capacities.


Assuntos
Síndrome da Imunodeficiência Adquirida/prevenção & controle , Saúde Global , Infecções por HIV/prevenção & controle , Política de Saúde , Cooperação Internacional , Feminino , Reforma dos Serviços de Saúde , Humanos , Masculino , Programas Nacionais de Saúde , Parcerias Público-Privadas , Estados Unidos
10.
Health Promot Pract ; 17(4): 569-77, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-26315033

RESUMO

Objective To examine the process of implementing, disseminating, and sustaining a pediatric pedestrian safety program in Miami-Dade County Public Schools as well as its utilization by education practitioners. Method A review of the programmatic phases, grant funding, publications, partnerships, curriculum completion data, teacher trainings, and 31 WalkSafe Curriculum Dissemination Surveys. Results The program has maintained partnerships with the school district, trauma centers, and other important stakeholders since the program's inception while grant funding has enabled the development, growth, and continuation of the program. Survey responses indicated the curriculum is easy to use and age-appropriate for learning, as well as identified sustainable measures for the future. Conclusion A multicomponent approach is essential for piloting, implementing, and sustaining an evidence-based pedestrian safety program in South Florida's public schools. Sustainable partnerships, policy through school board support, continued grant funding, community involvement, and evolving with the needs of schools and their communities are vital to sustaining program presence in the community.


Assuntos
Acidentes de Trânsito/prevenção & controle , Promoção da Saúde/organização & administração , Pedestres , Instituições Acadêmicas/organização & administração , Ferimentos e Lesões/prevenção & controle , Adolescente , Criança , Currículo , Humanos , Desenvolvimento de Programas , Segurança
11.
Breast J ; 17(5): 521-4, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21726350

RESUMO

We report a case of a 93-year-old woman who was diagnosed with estrogen receptor (ER)-positive, progesterone receptor-positive, T2N0M0 (stage I) breast cancer (BC) at the age of 45. Twenty-two years later, she was diagnosed with metastatic lesions to the lungs consistent with the breast primary. Her disease was stable on tamoxifen, anastrozole, and exemestane for 14 years. Subsequently, she was found to have metastatic lesions to thoracic spine as well as progressively increasing bilateral pleural effusions. At that time, she was deemed not to be a good candidate for chemotherapy and therapy was changed to fulvestrant. Two years later (38 years after initial diagnosis of BC), she was diagnosed with new metastatic liver lesions; although her pulmonary and bone metastases remained stable. Therefore, she was started on palliative chemotherapy with single-agent capecitabine. The treatment was discontinued after the second cycle upon the patient's request owing to grade 2 hand and foot syndrome. She expired 2 years later after fighting BC for four decades. She survived for 18 years after the diagnosis of metastatic breast cancer (MBC) while maintaining a good quality of life. To the authors' knowledge, this is the first reported case in the literature with the longest overall survival in a patient with MBC. We provide a detailed clinical analysis in conjunction with a brief literature review.


Assuntos
Neoplasias Ósseas/secundário , Neoplasias da Mama/patologia , Neoplasias da Mama/terapia , Carcinoma Ductal de Mama/secundário , Neoplasias Hepáticas/secundário , Neoplasias Pulmonares/secundário , Idoso , Idoso de 80 Anos ou mais , Neoplasias Ósseas/tratamento farmacológico , Neoplasias Ósseas/radioterapia , Neoplasias da Mama/diagnóstico , Carcinoma Ductal de Mama/diagnóstico , Carcinoma Ductal de Mama/terapia , Evolução Fatal , Feminino , Humanos , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Pulmonares/tratamento farmacológico , Pessoa de Meia-Idade , Fatores de Tempo
12.
Breast Cancer Res Treat ; 123(2): 427-35, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20585851

RESUMO

In order to examine the efficacy and safety of nanoparticle albumin-bound paclitaxel (nab-P) in combination with bevacizumab (B) and gemcitabine (G) for the first-line treatment of patients with HER2-negative metastatic breast cancer (MBC). In this single-center, open-label phase II trial, patients with HER2-negative MBC received gemcitabine 1500 mg/m(2), nab-paclitaxel 150 mg/m(2), and bevacizumab 10 mg/kg (each administered intravenously) on days 1 and 15 of a 28-day cycle. The primary end point was progression free survival (PFS); secondary end points were overall response rate (ORR), complete (CR) and partial (PR) response rates, clinical benefit (ORR + stable disease), overall survival (OS), and safety. Thirty patients were enrolled. One patient was ineligible and was not included in analysis. Median PFS was 10.4 months (95% CI: 5.6-15.2 months). ORR was 75.9%, comprising eight (27.6%) CRs and 14 (48.3%) PRs; five patients had stable disease (SD) and two patients (6.9%) had progressive disease (PD) as their best response. The clinical benefit rate was 93.1% (27/29) in the overall group and 84.6% in the triple-negative cohort (11/13). The 18-month survival rate was 77.2% (95% CI: 51.1-90.5%). Eight (27.6%) patients experienced grade 3 or 4 toxicity: grade 4 neutropenic fever (n = 1) and grade 3 infection (n = 6), leukopenia, thrombocytopenia, peripheral neuropathy, seizure, shortness of breath, hematuria, and cardiac tamponade (one each). First-line therapy with nab-P, B, and G demonstrated a median PFS of 10.4 months and a 75.9% ORR with acceptable toxicity; this novel combination warrants investigation in a randomized study.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias da Mama Masculina/tratamento farmacológico , Neoplasias da Mama/tratamento farmacológico , Receptor ErbB-2/análise , Adulto , Idoso , Albuminas/administração & dosagem , Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais Humanizados , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Bevacizumab , Neoplasias da Mama/química , Neoplasias da Mama/mortalidade , Neoplasias da Mama/secundário , Neoplasias da Mama Masculina/química , Neoplasias da Mama Masculina/mortalidade , Neoplasias da Mama Masculina/secundário , Desoxicitidina/administração & dosagem , Desoxicitidina/análogos & derivados , Intervalo Livre de Doença , Esquema de Medicação , Feminino , Florida , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Paclitaxel/administração & dosagem , Modelos de Riscos Proporcionais , Medição de Risco , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento , Gencitabina
13.
J Am Chem Soc ; 131(17): 6056-7, 2009 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-19400589

RESUMO

Thermodynamic stereocontrol of the (hexamethyldisilazide)magnesium enolates of propiophenone in THF is reported. The overall stereoselectivity proves to be very sensitive to concentration, since dimeric species with bridging enolates show no stereoselectivity while monomeric enolates show a very strong thermodynamic preference for the Z enolate. Kinetically, interconversion among aggregates is remarkably slow, whereas stereoisomerization of the monomer, even in the absence of a proton source such as ketone or amine, is remarkably fast. Furthermore, stereoisomerization takes place in the absence of a proton source or excess ketone. These observations contrast with accepted views of these fundamentally important processes and have implications for understanding the identity and reactivity of metal enolates.


Assuntos
Álcoois/química , Magnésio/química , Compostos Organometálicos/química , Termodinâmica , Furanos/química , Cinética , Conformação Molecular , Propiofenonas/química , Estereoisomerismo , Fatores de Tempo
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