Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
1.
Health Promot Pract ; : 15248399231221779, 2024 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-38264944

RESUMO

The Supplemental Nutrition Assistance Program-Education (SNAP-Ed) provides nutrition education and support for healthy living in SNAP-qualifying communities. SNAP-Ed supports policy, systems, and environmental (PSE) efforts to make the healthy choice an easier choice. SNAP-Ed implementers have widely adopted healthy eating PSE supports. However, physical activity (PA) PSE strategies are less common, with limited awareness between states of how other SNAP-Ed implementers approach PA-focused PSE work. Physical Activity Policy, Research, and Evaluation Network (PAPREN) Rural Active Living Workgroup project members sought to explore how Extension-based SNAP-Ed implements PA-focused PSE approaches. A sample of Extension-based SNAP-Ed program (n = 8) leaders were purposefully recruited from eligible universities in six of the seven SNAP-Ed regions. An interview guide to systematically collect information about current Extension SNAP-Ed implementation focused on PA PSE strategies was developed iteratively by the PAPREN Rural Active Living Workgroup Extension PA PSE project team. PA PSE Extension SNAP-Ed implementation efforts occurred at the state, county, and community levels and/or within local organizations. PA PSEs included school PA policy change, shared-use agreements, active transportation promotion, park development, walking challenges, and PA-promoting signage. All interviews highlighted the importance of partnerships at local, county, and state levels for PSE efforts. Extension-based SNAP-Ed shows potential to bring community partners together to plan and implement PA-focused PSE approaches. With a focus on SNAP-eligible people and substantial geographic reach, Extension SNAP-Ed is uniquely situated as a public health partner to broadly implement PA PSE changes.

2.
J Healthy Eat Act Living ; 3(1): 36-45, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37794919

RESUMO

The Physical Activity Guidelines for Americans (Guidelines) advises older adults to be as active as possible. Yet, despite the well documented benefits of physical activity just 12.8% of those ages 65 and older meet the Guidelines. To address this, the U.S. Department of Health and Human Services (HHS) developed a Midcourse Report focused on effective strategies to improve older adult physical activity behaviors. The first step in this process was a systematic literature review. A literature review team was contracted to examine the evidence on key settings and effective behavioral intervention strategies, as well as effective policy, systems, and environmental (PSE) approaches, to improve physical activity among older adults. The PSE search employed an equity-centered framework adapted to researching PSE approaches for improving physical activity outcomes in older adults. Sixteen thousand eight hundred and eighty-three titles and abstracts were screened, and 734 full articles were reviewed for inclusion. Of those, 64 original research articles were included for the final review to answer two questions, one (plus 5 sub-questions) focused on Settings/Strategies literature (45 studies) and one (plus 2 sub-questions) focused on PSE literature (19 studies). The literature review process identified key settings and evidence-based strategies to support older adults in becoming more physically active, and provides a foundation for the Physical Activity Guidelines for Americans Midcourse Report: Implementation Strategies for Older Adults. More research is needed to address how factors related to equity and psychosocial constructs influence physical activity behaviors among older adults.

3.
J Healthy Eat Act Living ; 3(1): 7-18, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37794922

RESUMO

Lee and Cubbin's (2009) call for a "socially just" Ecological Model of Physical Activity (EMPA) prompted an inquiry into physical activity (PA), active living (AL) research that advances social justice framed as a set of equity-centered principles for research. In response to the call, we conducted a scoping review to explore how PAAL research has operationalized equity to advance a socially-just EMPA. We searched for original research, published between 2010 and 2020, using key terms for 'physical activity' and 'equity' that produced 5,152 non-duplicated records. Title-abstract screening for exclusion/inclusion criteria disqualified 4,392 records. A review protocol and coding guide was developed, piloted, and revised by team members. The remaining 760 abstracts were reviewed and consensus coded for PA Variable (dependent or independent) and Factor (individual outcome or contextual exposure), Equity (population demographic or social-environmental determinant), and Social Ecological Milieu (SEM) (PAAL-specific or SEM-general policy, system, or environment (PSE) operations. Of the 463 studies selected, PA codified as an individual outcome (67%) more often than as a contextual-exposure (33%) factor. Equity codified more frequently as a population demographic (69%) rather than as a social-environmental determinant (31%). The SEM codified as PAAL-specific (44%) or as SEM-general (56%) PSE factors. Based on multistep study abstract reviews, the selected studies more often missed the opportunity to center equity in PAAL research by examining social, environmental, political, and systemic factors as institutionalized inequities at the root of PAAL disparities. We will not achieve a socially-just EMPA without shared conceptualizations of equity followed by intentional action.

4.
Gac Sanit ; 36(5): 459-467, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34172312

RESUMO

OBJECTIVE: To perform a cross-cultural adaptation, content validity and feasibility of The School Physical Activity and Nutrition Environment Tool (SPAN-ET) for the Spanish context. It is a valuable tool for making comprehensive assessments of school environments in three environmental categories: policy, situation/social, and physical. METHOD: We followed the cross-cultural adaptation guidelines which consist of a five-stage methodological approach: 1) forward translation, 2) synthesis, 3) back translation, 4) adaptation to the Spanish context, and 5) pilot testing. In addition, an expert panel performed a content validity analysis to assess the level of comprehensibility, applicability, and cultural appropriateness of the SPAN-ET for its use in Spain. The pilot test was carried out in five schools to assess the feasibility of the tool in the Spanish context. RESULTS: After applying the guidelines for the translation and cultural adaptation of the SPAN-ET into the Spanish context, the new tool (SPAN-ET-ES) preserves the main dimensions of the original document to evaluate school environments in Spain. The evaluation of the SPAN-ET-ES, done by an expert panel, concluded that items included in the revised version of the SPAN-ET-ES were relevant (S-CVI/Ave=0.96), clear (S-CVI/Ave=0.96), simple (S-CVI/Ave=0.98), and non-ambiguous (S-CVI/Ave=0.98) for the Spanish context. Finally, the pilot test offered empirical evidence for the feasibility and content validity of the SPAN-ET-ES at assessing school environments in Spain. CONCLUSIONS: SPAN-ET-ES is a feasible tool for assessing nutrition and physical activity environments at schools in Spain.


Assuntos
Comparação Transcultural , Traduções , Exercício Físico , Estudos de Viabilidade , Humanos , Reprodutibilidade dos Testes , Instituições Acadêmicas , Inquéritos e Questionários
5.
Perm J ; 252021 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-35348067

RESUMO

INTRODUCTION: The Southern California region of Kaiser Permanente developed a COVID-19 Home Monitoring program as an alternative to hospital admission to decrease hospital bed days and mitigate the adverse effects of a surge. To date, more than 15,000 patients have been enrolled and approximately 10% of enrolled patients have been escalated to hospital care for timely treatment. Our objective is to describe our COVID-19 Home Monitoring program and present early results. METHODS: We conducted an observational retrospective study of all patients enrolled in the COVID-19 Home Monitoring program between April 13, 2020 through February 12, 2021. Data analysis conducted includes patient demographics, enrollment, entry points, length of stay, mortality, additional treatment, utilization, adherence, satisfaction, and alert triggers. RESULTS: A total of 12,461 of 13,055 patients (95.5%) recovered and completed the program, 1387 patients (10.6%) were admitted to the hospital, and 20 patients (0.2%) died while they were being monitored at home. The mortality rate at 30 days from enrollment was 1.6%. Hospital length of stay for ambulatory patients receiving oxygen only was 5.4 days compared to 3.1 days for those ambulatory patients receiving oxygen, dexamethasone, and remdesivir. CONCLUSION: COVID-19 home monitoring appears to be safe and effective. Initial data suggest it can serve as an alternative to hospitalization, decreasing hospital length of stay when patients receive therapies in the ambulatory setting otherwise reserved for the hospital. Initial results of this Home Monitoring program appear to be promising, and a longer term prospective study is warranted.


Assuntos
COVID-19 , Serviços de Assistência Domiciliar , California , Humanos , Estudos Prospectivos , Estudos Retrospectivos
6.
J Sch Health ; 89(6): 435-443, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30937920

RESUMO

BACKGROUND: Classroom-based physical activity (CBPA) breaks are a common strategy to increase elementary school children's physical activity (PA) levels. There is limited research examining how teacher-level factors impact teacher implementation of CBPA breaks. In this study, we assessed the relationship of teacher-level factors with teacher use of a CBPA resource. METHODS: We randomized 6 elementary schools in rural Oregon into control (N = 3) or intervention (N = 3) conditions. Each teacher at intervention schools received the CBPA resource. Teachers at control schools received 1 CBPA-Toolkit per grade level to share, and received no training. We surveyed teachers on their use of the toolkit, implementation support and self-efficacy, and value for PA. Logistic regression was used to examine the odds of toolkit use by teacher-level factors. RESULTS: Among survey respondents (N = 83), 57% were self-identified toolkit users and 48% attended a training. Training participation and teacher implementation self-efficacy were associated with greater odds of using the toolkit (odds ratio, OR = 7.76 [95% confidence interval, CI = 1.39-43.19] and OR = 5.54 [95% CI = 1.24-23.87], respectively). CONCLUSION: CBPA tools supported with training aimed at developing teachers' implementation self-efficacy increased the likelihood of teachers employing CBPA tools.


Assuntos
Exercício Físico , Capacitação em Serviço/organização & administração , Professores Escolares , Instituições Acadêmicas/organização & administração , Adulto , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Percepção , Adulto Jovem
8.
J Phys Act Health ; 15(9): 637-643, 2018 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-29584527

RESUMO

BACKGROUND: Classroom-based physical activity (CBPA) breaks are a cost-effective strategy to promote physical activity (PA) at school. Despite teachers' critical roles in sustained implementation of CBPA breaks, few studies examined the association of teacher-level factors with student PA levels, and none focused on rural schools. METHODS: We monitored children's PA levels over 4 consecutive school days at 6 rural Oregon elementary schools with Walk4Life pedometers. During the same week, teachers recorded all student PA opportunities (recess, PE, and CBPA breaks) and answered a 26-item questionnaire about factors influencing their use of CBPA breaks. Mixed-effects models were used to associate teacher-level factors and PA opportunities with children's moderate to vigorous PA (MVPA; in minutes per day), controlling for child-level covariates. RESULTS: When teachers valued PA, students accumulated more MVPA (1.07 min/d; P < .01) than students of teachers reporting low PA value. Students did more MVPA (1 min/d; P < .001) when teachers agreed the school operating conditions posed barriers to providing PA than when teachers disagreed that barriers existed. PE classes contributed significantly to student's PA levels. CONCLUSION: Provision of PE, increasing teacher value for PA, and further investigation of how teacher-level factors relate to students' MVPA levels during CBPA breaks at rural elementary schools are warranted.


Assuntos
Exercício Físico/fisiologia , Educação Física e Treinamento/estatística & dados numéricos , Jogos e Brinquedos , População Rural/estatística & dados numéricos , Professores Escolares/psicologia , Estudantes/estatística & dados numéricos , Actigrafia/métodos , Criança , Feminino , Humanos , Masculino , Instituições Acadêmicas/estatística & dados numéricos , Inquéritos e Questionários
9.
Prev Med Rep ; 8: 38-41, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28840095

RESUMO

Among rural families, rates of both child obesity and household food insecurity (FI) are higher compared to non-rural families. These disparities result from a complex interplay of social and environmental conditions that influence behavior. The Transtheoretical Model suggests individual readiness to change underlies success in modifying obesity-preventing behaviors; however, whether an association between readiness to change obesity-related behaviors and FI status among rural families exists is unknown. We examined the association between readiness to change family-level nutrition and physical activity (PA) behaviors that predict child obesity and family FI status within a sample of rural families to better understand these relationships. Families (n = 144) were recruited from six rural Oregon communities in 2013. Families completed a FI screener and the Family Stage of Change Survey (FSOC), a measure of readiness to change family-level nutrition and PA behaviors associated with obesity. Demographic differences by FI status were explored, and regression was applied to examine relationships between FI and FSOC scores, adjusting for relevant covariates. Among FI families (40.2%), more were non-white (77.8% vs. 22.2%; p = 0.036) and had lower adult education (30.4% vs. 11.8% with > high school degree; p = 0.015) compared to non-FI families. After adjusting for education, race, ethnicity, and eligibility for federal meal programs, readiness to provide opportunities for PA was lower among FI families (p = 0.002). These data highlight a need to further investigate how food insecurity and low readiness to provide PA opportunities, i.e. "physical activity insecurity" may be contributing to the higher obesity rates observed among rural children and families.

10.
Prog Community Health Partnersh ; 11(2): 183-196, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28736411

RESUMO

BACKGROUND: Individual risk factors for obesity are well-known, but environmental characteristics that influence individual risk, especially in rural communities, are not confirmed. Rural communities face unique challenges to implementing environmental strategies, such as walkability, aimed at supporting weight healthy lifestyles. Cooperative Extension, a community-embedded weight health partner, convened and engaged community members in self-exploration of local resources and readiness to change environmental characteristics perceived to promote unhealthy eating and inactivity. This approach leveraged Extension's mission, which includes connecting rural communities with land-grant university resources. OBJECTIVES: HEAL MAPPS™ (Healthy Eating Active Living Mapping Attributes using Participatory Photographic Surveys) was developed as a participatory action research methodology. Adopted by Extension community partners, HEAL MAPPS™ involved residents in photomapping, characterizing, and communicating lived experiences of their rural community, and prioritizing interventions to change the obesogenic context. METHODS: Extension educators serving rural communities in six Western U.S. states were trained to implement HEAL MAPPS™. Extension engaged community members who mapped and evaluated their encounters with environmental attributes that shape their dietary and activity patterns. The method partnered residents with decision makers in identifying issues, assessing resources and readiness, and prioritizing locally relevant environmental strategies to reduce access disparities for rural populations with high obesity risk. CONCLUSIONS: HEAL MAPPS™ revealed differences in resource availability, accessibility, and affordability within and among rural communities, as well as in readiness to address the obesogenic context. Extension functioned successfully as the backbone organization, and local community health partner, cooperatively implementing HEAL MAPPS™ and engaging constituents in shaping weight healthy environments.


Assuntos
Pesquisa Participativa Baseada na Comunidade , Promoção da Saúde/métodos , Obesidade/prevenção & controle , Saúde Pública , Planejamento Ambiental , Feminino , Grupos Focais , Pesquisa sobre Serviços de Saúde , Humanos , Estilo de Vida , Masculino , Fotografação , Fatores de Risco , Saúde da População Rural , População Rural , Estados Unidos
11.
Health Educ Behav ; 44(4): 648-657, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28125908

RESUMO

BACKGROUND: Family homes are a key setting for developing lifelong eating and physical activity habits, yet little is known about how family home nutrition and physical activity (FNPA) environments influence food insecurity (FI) and childhood obesity, particularly in rural settings. AIMS: This study examined associations among FNPA, FI, and body mass index (BMI) in rural children. METHOD: Parents of 186 elementary school-age children completed FNPA and FI surveys. Child anthropometrics were directly measured. Logistic and linear regressions were used to examine associations. RESULTS: Approximately 37% of children were overweight/obese; 43% of families were at risk for FI. Children whose families limited watching TV while eating were less likely to be obese (odds ratio [OR] = 0.56, p = .03) as were children whose families monitored intake of chips, cookies, and candy (OR = 0.54, p = .01). FI was higher in obese than normal weight children (OR = 11.00, p = .003) but only among families not eligible to receive free/reduced-cost school meals. Among eligible families, lower odds of FI were found for those who ate meals together often (OR = 0.31, p = .04) and for those with children frequently enrolled in organized sports/activities (OR = 0.65, p = .04). Findings were not significant after adjusting for multiple comparisons. DISCUSSION: Results suggest that favorable FNPA factors were associated with healthier BMI and lower odds of FI. CONCLUSION: Opportunities for healthy eating at home may support rural children's weight health. Additional resources may be necessary to promote food security among low-income families. Future research is warranted to better understand FNPA in relationship to the disproportionate rates of obesity and FI in rural populations.


Assuntos
Índice de Massa Corporal , Abastecimento de Alimentos , Avaliação Nutricional , População Rural , Criança , Dieta , Exercício Físico/fisiologia , Comportamento Alimentar , Feminino , Humanos , Masculino , Obesidade Infantil , Pobreza , Inquéritos e Questionários
12.
J Sch Health ; 86(1): 39-47, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26645419

RESUMO

BACKGROUND: Practical tools are needed that reliably measure the complex physical activity (PA) and nutrition environments of elementary schools that influence children's health and learning behaviors for obesity prevention. The School Physical Activity and Nutrition-Environment Tool (SPAN-ET) was developed and beta tested in 6 rural Oregon elementary schools. METHODS: Extension educators were trained to assess elementary school PA and nutrition environments using the SPAN-ET. Two auditors per school worked with school health stakeholders and collected data via document review, interviews, and direct observations. A reliability analysis using percent agreement and kappa statistics was performed to determine consistency between independent auditors. Content analyses of qualitative data were used to triangulate intercoder ratings, verify evidence, and improve reliability. RESULTS: Across the 6 schools, for all 182 measured criteria (PA = 103; nutrition = 79), the percent agreement ranged from 80.8% to 96.8% and kappa from 0.61% to 0.94. CONCLUSION: The SPAN-ET was a reliable instrument for assessing the quality of elementary school PA and nutrition environments, and a sensitive measure for objectively identifying specific attributes of SPAN-ET areas of interest to target for school environmental and policy improvements aimed at supporting students' obesity preventing behaviors.


Assuntos
Serviços de Alimentação , Promoção da Saúde , Educação Física e Treinamento , Serviços de Saúde Escolar , Criança , Exercício Físico , Feminino , Humanos , Entrevistas como Assunto , Masculino , Obesidade/prevenção & controle , Observação , Oregon , Pesquisa Qualitativa , Instituições Acadêmicas
13.
J Appl Gerontol ; 35(10): 1095-120, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-25608869

RESUMO

The growing numbers of older adults in the United States will have a significant impact on community resources, which will affect the ability of residents to live and thrive in their local community regardless of age. For this study, we applied explanatory sequential mixed methods and community-based participatory research (CBPR) to discover how attributes of the physical, social, and service environments determine residents' perceptions of community age-friendliness and conditions for aging-in-place. A population survey measuring county residents' (n = 387) perceptions and importance of community resources that support community livability are explained by thematic results of the CBPR, that is, emergent proximal and distal age-friendly factors. Our qualitative approach engaged local people (n = 237) in participatory processes to study and share perceptions of environmental attributes in six communities in one Oregon county. Findings are integrated to explain similarities and differences in older residents' lived experience of rural and urban settings with regard to age-friendly foci.


Assuntos
Planejamento Ambiental , Vida Independente , Características de Residência , Meio Social , Seguridade Social , Adulto , Idoso , Serviços de Saúde Comunitária , Pesquisa Participativa Baseada na Comunidade , Feminino , Mapeamento Geográfico , Habitação , Humanos , Masculino , Pessoa de Meia-Idade , Oregon , Percepção , Fotografação , População Rural , Apoio Social , Inquéritos e Questionários , População Urbana , Adulto Jovem
14.
Nutrients ; 7(12): 9707-20, 2015 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-26610566

RESUMO

Obesity and food insecurity rates are higher among rural compared to non-rural populations. Little is known, however, about how family-home environments influence childhood obesity-related behaviors, particularly in rural settings. This study examined associations between the family-home nutrition (FN) environment, food insecurity, and dietary intake (fruits, vegetables, whole grains, dairy, protein foods, and added sugars) in rural elementary school-age children (grades K-5/6; n = 102). Parents/caregivers completed surveys on FN, food insecurity, and the Block Kids Food Screener (BKFS). Body mass index (BMI, kg/m2) was calculated from measured height and weight. Approximately 33% of children were classified as overweight/obese and 28% of families were at-risk for food insecurity. Multivariable linear regression analyses examined associations between dietary intakes with FN and food insecurity. More favorable FN scores were associated with lower added sugar intake (B = -1.38, p = 0.04) and higher vegetable (B = 0.15, p < 0.001), fruit (B = 0.71, p = 0.01), and dairy (B = 0.31, p < 0.001) intakes. No significant associations were found between food insecurity and dietary intake. Given the association between higher FN scores and more favorable dietary intake, promoting healthy FN environments among rural children is warranted.


Assuntos
Dieta , Avaliação Nutricional , População Rural , Adolescente , Criança , Estudos Transversais , Proteínas Alimentares , Ingestão de Energia , Comportamento Alimentar , Feminino , Abastecimento de Alimentos , Frutas , Humanos , Masculino , Inquéritos e Questionários , Verduras , Grãos Integrais
15.
Prev Med Rep ; 2: 478-82, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26844106

RESUMO

OBJECTIVE: To evaluate the relationship between physical activity (PA, min/school-day) at school and body mass index (BMI, kg/m(2)) among rural elementary-aged children. METHODS: Height (cm), weight (kg), and PA were measured for 1767 children (5-12 years) enrolled in six rural Oregon elementary schools in fall, 2013. PA at school was measured over four days using Walk4Life pedometers. Children with ≥ 3 valid monitoring days (n = 1482) were included in analyses. Means (min/d) were calculated for wear time, total PA (TPA: combined light, moderate, vigorous PA), and moderate to vigorous PA (MVPA: step count > 120/min). BMI z-scores were calculated and regression models were run to examine the relationship between PA and BMI z-scores, adjusting for wear time, sex, and grade. RESULTS: Overweight (38.1%: BMI ≥ 85(th) percentile for age and sex) and obesity (19.4%: BMI ≥ 95(th) percentile) prevalence was similar for boys (n = 782) and girls (n = 700). More MVPA was associated with lower BMI (P < 0.001), independent of sex, wear time or grade. Mean MVPA was 18.9 +/- 8 min/d, versus 15.2 +/- 6.7 min/d for healthy-weight and obese children, respectively. CONCLUSIONS: Children are not meeting minimum MVPA recommendations (60 min/d) during school hours. Efforts to promote PA for obesity prevention in rural elementary schools should focus on increasing opportunities for MVPA.

16.
Blood ; 104(12): 3437-44, 2004 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-15304397

RESUMO

In most myeloid leukemias induced in mice by gamma-radiation, one copy of chromosome 2 has suffered a deletion. To search for a potential tumor suppressor gene in that region, we have delineated the deletions in a panel of these tumors. A commonly deleted region of 2 megabase pairs (Mbp) includes the gene encoding the PU.1 transcription factor, a powerful inducer of granulocytic/monocytic differentiation. Significantly, in 87% of these tumors the remaining PU.1 allele exhibited point mutations in the PU.1 DNA binding domain. Surprisingly, 86% of these mutations altered a single CpG, implicating deamination of deoxycytidine, a common mutational mechanism, as the origin of this lesion. The "hot spot" resides in the codon for a contact residue essential for DNA binding by PU.1. In keeping with a tumor suppressor role for PU.1, enforced expression of wild-type PU.1 in the promyelocytic leukemia cells inhibited their clonogenic growth, induced monocytic differentiation, and elicited apoptosis. The mutant PU.1 found in tumors retained only minimal growth suppressive function. The results suggest that PU.1 normally suppresses development of myeloid leukemia by promoting differentiation and that the combination of gene deletion and a point mutation that impairs its ability to bind DNA is particularly leukemogenic.


Assuntos
Deleção de Genes , Leucemia Mieloide/genética , Mutação Puntual , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/fisiologia , Transativadores/genética , Transativadores/fisiologia , Animais , Sítios de Ligação/genética , Diferenciação Celular/genética , Proliferação de Células , Células Clonais/patologia , DNA/metabolismo , Leucemia Mieloide/etiologia , Masculino , Camundongos , Proteínas Proto-Oncogênicas/química , Transativadores/química , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/fisiologia
17.
J Mol Biol ; 337(3): 611-9, 2004 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-15019781

RESUMO

We used selective acylation of 2'-amine-substituted nucleotides to visualize local backbone conformations that occur preferentially at bulged sites in DNA duplexes. 2'-Amine acylation reports local nucleotide flexibility because unconstrained 2'-amino nucleotides more readily reach a reactive conformation in which the amide-forming transition state is stabilized by interactions between the amine nucleophile and the adjacent 3'-phosphodiester group. Bulged 2'-amine-substituted cytidine nucleotides react approximately 20-fold more rapidly than nucleotides constrained by base-pairing at 35 degrees C. In contrast, base-paired 2'-amine-substituted nucleotides flanked by a 5' or 3' bulge react two- or six-fold more rapidly, respectively, than the perfectly paired duplex. The relative lack of 2'-amine reactivity for nucleotides adjacent to a DNA bulge emphasizes, first, that structural perturbations do not extend significantly into the flanking duplex structure. Second, the exquisite sensitivity towards very local perturbations in nucleic acid structure suggests that 2'-amine acylation can be used to chemically interrogate deletion mutations in DNA. Finally, these data support the mechanical interpretation that the reactive ribose conformation for 2'-amine acylation requires that the base lies out of the helix and in the major groove, a mechanistic insight useful for designing 2'-amine-based sensors.


Assuntos
DNA/química , Acilação , Aminas/química , Pareamento de Bases , Citidina/química , Cinética , Conformação de Ácido Nucleico , Maleabilidade
18.
Biochemistry ; 41(21): 6866-74, 2002 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-12022892

RESUMO

2'-Amine-substituted nucleotides in hybridized duplexes can be chemically tagged in an acylation reaction that is faster for mismatched or flexible nucleotides than for residues constrained by base pairing. Here we explore mismatch and hybridization detection using probe oligodeoxynucleotides containing single 2'-aminocytidine or -uridine nucleotides annealed to DNA or RNA targets under nonstringent conditions, below T(m). Consistent with a mechanism in which 2'-amine acylation is gated by local nucleotide flexibility, we find that efficient acylation is correlated with formation of weaker or fewer hydrogen bonds in base pair mismatches. Using 2'-aminocytidine-containing probes annealed to both DNA and RNA targets, mismatches are reliably detected as rapid selective acylation of the 2'-amine group in two sequence contexts. For probe oligonucleotides containing 2'-aminouridine residues, good discrimination between U-A base pairs and U-G mismatches could be obtained for DNA-DNA but not for DNA-RNA duplexes upon the introduction of a single 2'-O-Me group 5' to the 2'-amino nucleotide. The 2'-O-Me group introduces a structural perturbation, presumably to a more A-form-like structure, that exaggerates local flexibility at mismatches in DNA strands. Thus, 2'-amine acylation can be used to interrogate all possible mismatches in DNA-DNA duplexes and mismatches involving 2'-amine-substituted cytidine nucleotides in DNA-RNA heteroduplexes. Applications of this chemistry include detecting and chemically proofreading single nucleotide polymorphisms in both DNA and RNA targets and quantifying absolute amounts of RNA.


Assuntos
Pareamento Incorreto de Bases , DNA/metabolismo , Ácidos Nucleicos Heteroduplexes/metabolismo , Sondas de Oligonucleotídeos/metabolismo , RNA/metabolismo , Acilação , DNA/química , Ácidos Nucleicos Heteroduplexes/química , RNA/química , Termodinâmica
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA