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1.
Nurs Crit Care ; 24(5): 256-262, 2019 09.
Artículo en Inglés | MEDLINE | ID: mdl-30460729

RESUMEN

INTRODUCTION: Treatment of infections that require high-level isolation can cause anxiety and fear among health care workers. Adequate and complete multi-professional simulation-based training could reduce those feelings and improve patient care. OBJECTIVE: The purpose of this study was to assess the impact of multi-professional simulation-based training on the risk perception and preparedness of health care workers (registered nurses, doctors and ancillary staff) who care for patients assessed to be at risk or confirmed to have Ebola, level 3-4 biohazard. METHODS: A prospective before-after study was designed. Health care workers who participated in a multi-professional simulation training course to improve the care of patients potentially infected with Level 3 and 4 biohazards were evaluated about their risk perception. The training was based on clinical scenarios. The evaluation was conducted using questionnaire based on Likert scale. After the training, a satisfaction survey about the most important aspects of the course was also conducted. RESULTS: Fifty-eight health care workers participated in the training course, 22 of whom were registered nurses. Participants presented positive changes after the training, increasing their sense of security, predisposition and confidence (p < 0.000001 for all). CONCLUSION: Multi-professional simulation-based training significantly improves the perception of safety and preparedness of health care workers regarding the care of patients potentially infected with Ebola virus and other Level 3-4 biohazards. RELEVANCE TO CLINICAL PRACTICE: The implementation of educational training strategies - such as simulations - is beneficial in improving the capacity of response and coping, as well as in reducing feelings of fear and insecurity.


Asunto(s)
Adaptación Psicológica , Actitud del Personal de Salud , Personal de Salud/educación , Personal de Salud/psicología , Fiebre Hemorrágica Ebola/enfermería , Estrés Laboral/terapia , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Factores de Riesgo
2.
Biochem Biophys Res Commun ; 451(4): 603-8, 2014 Sep 05.
Artículo en Inglés | MEDLINE | ID: mdl-25128829

RESUMEN

Bluetongue virus core protein VP6 is an ATP hydrolysis dependent RNA helicase. However, despite much study, the precise role of VP6 within the viral capsid and its structure remain unclear. To investigate the requirement of VP6 in BTV replication, we initiated a structural and biological study. Multinuclear nuclear magnetic resonance spectra were assigned on his-tagged full-length VP6 (329 amino acid residues) as well as several truncated VP6 variants. The analysis revealed a large structured domain with two large loop regions that exhibit significant conformational exchange. One of the loops (amino acid position 34-130) could be removed without affecting the overall fold of the protein. Moreover, using a BTV reverse genetics system, it was possible to demonstrate that the VP6-truncated BTV was viable in BHK cells in the absence of any helper VP6 protein, suggesting that a large portion of this loop region is not absolutely required for BTV replication.


Asunto(s)
Virus de la Lengua Azul/genética , ARN Helicasas/química , Proteínas del Núcleo Viral/química , Animales , Virus de la Lengua Azul/fisiología , Cricetinae , Resonancia Magnética Nuclear Biomolecular , Fragmentos de Péptidos/aislamiento & purificación , Fragmentos de Péptidos/metabolismo , Replicación Viral
3.
Nucleic Acids Res ; 38(15): 5226-41, 2010 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-20410074

RESUMEN

Direct targeting of critical DNA-binding elements of a repressor by its cognate antirepressor is an effective means to sequester the repressor and remove a transcription initiation block. Structural descriptions for this, though often proposed for bacterial and phage repressor-antirepressor systems, are unavailable. Here, we describe the structural and functional basis of how the Myxococcus xanthus CarS antirepressor recognizes and neutralizes its cognate repressors to turn on a photo-inducible promoter. CarA and CarH repress the carB operon in the dark. CarS, produced in the light, physically interacts with the MerR-type winged-helix DNA-binding domain of these repressors leading to activation of carB. The NMR structure of CarS1, a functional CarS variant, reveals a five-stranded, antiparallel beta-sheet fold resembling SH3 domains, protein-protein interaction modules prevalent in eukaryotes but rare in prokaryotes. NMR studies and analysis of site-directed mutants in vivo and in vitro unveil a solvent-exposed hydrophobic pocket lined by acidic residues in CarS, where the CarA DNA recognition helix docks with high affinity in an atypical ligand-recognition mode for SH3 domains. Our findings uncover an unprecedented use of the SH3 domain-like fold for protein-protein recognition whereby an antirepressor mimics operator DNA in sequestering the repressor DNA recognition helix to activate transcription.


Asunto(s)
Proteínas Bacterianas/química , Regiones Operadoras Genéticas , Proteínas Represoras/química , Factores de Transcripción/química , Secuencia de Aminoácidos , Proteínas Bacterianas/genética , Sitios de Unión , ADN/química , Proteínas de Unión al ADN/química , Modelos Moleculares , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Resonancia Magnética Nuclear Biomolecular , Estructura Secundaria de Proteína , Factores de Transcripción/genética , Dominios Homologos src
4.
Nat Struct Mol Biol ; 27(5): 424-437, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-32398827

RESUMEN

Oncogene activation during tumorigenesis generates DNA replication stress, a known driver of genome rearrangements. In response to replication stress, certain loci, such as common fragile sites and telomeres, remain under-replicated during interphase and subsequently complete locus duplication in mitosis in a process known as 'MiDAS'. Here, we demonstrate that RTEL1 (regulator of telomere elongation helicase 1) has a genome-wide role in MiDAS at loci prone to form G-quadruplex-associated R-loops, in a process that is dependent on its helicase function. We reveal that SLX4 is required for the timely recruitment of RTEL1 to the affected loci, which in turn facilitates recruitment of other proteins required for MiDAS, including RAD52 and POLD3. Our findings demonstrate that RTEL1 is required for MiDAS and suggest that RTEL1 maintains genome stability by resolving conflicts that can arise between the replication and transcription machineries.


Asunto(s)
ADN Helicasas/genética , ADN Helicasas/metabolismo , G-Cuádruplex , Genoma Humano/genética , Mitosis , Animales , Línea Celular , ADN Helicasas/química , ADN Polimerasa III/genética , ADN Polimerasa III/metabolismo , Inestabilidad Genómica , Humanos , Inmunoprecipitación , Ratones , Enzimas Multifuncionales/genética , Enzimas Multifuncionales/metabolismo , Conformación de Ácido Nucleico , ARN Helicasas/genética , ARN Helicasas/metabolismo , Proteína Recombinante y Reparadora de ADN Rad52/genética , Proteína Recombinante y Reparadora de ADN Rad52/metabolismo , Recombinasas/genética , Recombinasas/metabolismo , Ribonucleasa H/genética , Ribonucleasa H/metabolismo
6.
Protein Sci ; 16(10): 2278-86, 2007 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-17766377

RESUMEN

TA0095 is a 96-residue hypothetical protein from Thermoplasma acidophilum that exhibits no sequence similarity to any protein of known structure. Also, TA0095 is a member of the COG4004 orthologous group of unknown function found in Archaea bacteria. We determined its three-dimensional structure by NMR methods. The structure displays an alpha/beta two-layer sandwich architecture formed by three alpha-helices and five beta-strands following the order beta1-alpha1-beta2-beta3-beta4-beta5-alpha2-alpha3. Searches for structural homologs indicate that the TA0095 structure belongs to the TBP-like fold, constituting a novel superfamily characterized by an additional C-terminal helix. The TA0095 structure provides a fold common to the COG4004 proteins that will obviously belong to this new superfamily. Most hydrophobic residues conserved in the COG4004 proteins are buried in the structure determined herein, thus underlying their importance for structure stability. Considering that the TA0095 surface shows a large positively charged patch with a high degree of residue conservation within the COG4004 domain, the biological function of TA0095 and the rest of COG4004 proteins might occur through binding a negatively charged molecule. Like other TBP-like fold proteins, the COG4004 proteins might be DNA-binding proteins. The fact that TA0095 is shown to interact with large DNA fragments is in favor of this hypothesis, although nonspecific DNA binding cannot be ruled out.


Asunto(s)
Proteínas Arqueales/química , Proteínas de Unión al ADN/química , Modelos Moleculares , Thermoplasma , Secuencia de Aminoácidos , Proteínas Arqueales/clasificación , Datos de Secuencia Molecular , Resonancia Magnética Nuclear Biomolecular , Pliegue de Proteína , Estructura Secundaria de Proteína , Alineación de Secuencia
7.
Nat Commun ; 8: 15987, 2017 07 11.
Artículo en Inglés | MEDLINE | ID: mdl-28695888

RESUMEN

The widespread application of high-throughput sequencing methods is resulting in the identification of a rapidly growing number of novel gene fusions caused by tumour-specific chromosomal rearrangements, whose oncogenic potential remains unknown. Here we describe a strategy that builds upon recent advances in genome editing and combines ex vivo and in vivo chromosomal engineering to rapidly and effectively interrogate the oncogenic potential of genomic rearrangements identified in human brain cancers. We show that one such rearrangement, an microdeletion resulting in a fusion between Brevican (BCAN) and Neurotrophic Receptor Tyrosine Kinase 1 (NTRK1), is a potent oncogenic driver of high-grade gliomas and confers sensitivity to the experimental TRK inhibitor entrectinib. This work demonstrates that BCAN-NTRK1 is a bona fide human glioma driver and describes a general strategy to define the oncogenic potential of novel glioma-associated genomic rearrangements and to generate accurate preclinical models of this lethal human cancer.


Asunto(s)
Benzamidas/uso terapéutico , Brevicano/genética , Glioma/genética , Indazoles/uso terapéutico , Fusión de Oncogenes , Receptor trkA/genética , Animales , Benzamidas/farmacología , Sistemas CRISPR-Cas , Ensayos de Selección de Medicamentos Antitumorales , Estudios de Factibilidad , Femenino , Edición Génica , Glioma/tratamiento farmacológico , Humanos , Indazoles/farmacología , Ratones Endogámicos C57BL , Ratones Desnudos , Neoplasias Experimentales , Cultivo Primario de Células , Receptor trkA/antagonistas & inhibidores
8.
J Ethnopharmacol ; 146(1): 311-7, 2013 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-23313391

RESUMEN

ETHNOPHARMACOLOGICAL RELEVANCE: Heteropterys brachiata is a plant species that has been used in traditional Mexican medicine for the treatment of nervous disorders. AIM OF THE STUDY: To evaluate the anxiolytic, anticonvulsant, antidepressant and sedative effects produced by the methanolic extract of Heteropterys brachiata (HbMeOH) in ICR mice. Additionally, we determine the acute toxicity profiles of the extract and the presence of its main constituents. MATERIAL AND METHODS: The neuropharmacological effects of the extract were evaluated using a variety of models, such as the elevated plus maze (EPM), the forced swimming test (FST), the pentobarbital potentiation test (PTBt), pentylenetetrazole-induced seizures test (PTZt), and the open field test (OFT). HPLC was employed for obtention of phytochemical profile. RESULTS: HbMeOH produced a significant antidepressant effect in FST at 500 and 750 mg/kg doses, while doses from 500 to 1500 mg/kg exhibited a clear dose-dependent anxiolytic activity in EPM. A dose of 500 mg/kg showed a significant anticonvulsant activity in PTZt and an absence of sedation effects in PTBt. The main compounds of HbMeOH were chlorogenic acid and chlorogenic acid methyl ester, as well as less abundant terpene-type compounds. Furthermore, the extract was either safe with no deaths in mice treated orally with 2000 mg/kg. CONCLUSIONS: HbMeOH extract which contains mainly hydroxycinnamic acids and triterpene-type compounds, possesses antidepressant, anxiolytic and anticonvulsive properties and can be considered safe or of low toxicity when orally administrated. These findings lend pharmacological justification to the traditional use of Heteropterys brachiata in the treatment of nervous disorders.


Asunto(s)
Ansiolíticos/uso terapéutico , Anticonvulsivantes/uso terapéutico , Antidepresivos/uso terapéutico , Malpighiaceae , Extractos Vegetales/uso terapéutico , Animales , Ansiedad/tratamiento farmacológico , Ácido Clorogénico/análogos & derivados , Ácido Clorogénico/aislamiento & purificación , Ácido Clorogénico/uso terapéutico , Femenino , Ratones , Ratones Endogámicos ICR , Pentilenotetrazol , Componentes Aéreos de las Plantas , Extractos Vegetales/química , Convulsiones/inducido químicamente , Convulsiones/tratamiento farmacológico , Pruebas de Toxicidad Aguda
10.
Biomol NMR Assign ; 3(1): 37-40, 2009 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-19636942

RESUMEN

The CarS antirepressor activates a photo-inducible promoter in Myxococcus xanthus by physically interacting with the CarA repressor and eliminating the latter's binding to operator DNA. Interestingly, interactions with both CarS and operator are crucially dependent on the DNA recognition helix of the CarA winged-helix DNA-binding domain. The CarA-CarS and the CarA-operator interfaces therefore overlap, and CarS may have structural features that mimic operator DNA. CarS has no known sequence homologues and its Gly and Pro contents are unusually high. Here, we report (1)H, (13)C and (15)N backbone and side chain assignments of CarS1, an 86-residue truncated yet fully functional variant of CarS. Secondary structural elements inferred from these data differ from those predicted from sequence.


Asunto(s)
Proteínas Bacterianas/química , Espectroscopía de Resonancia Magnética/métodos , Factores de Transcripción/química , Secuencia de Aminoácidos , Isótopos de Carbono/química , Datos de Secuencia Molecular , Isótopos de Nitrógeno/química , Estructura Terciaria de Proteína , Subunidades de Proteína , Protones , Homología de Secuencia de Aminoácido
11.
Chemistry ; 14(2): 488-99, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-17943702

RESUMEN

Incorporation of disulfide bonds to stabilize protein and peptide structures is not always a successful strategy. To advance current knowledge on the contribution of disulfide bonds to beta-hairpin stability, a previously reported beta-hairpin-forming peptide was taken as a template to design a series of Cys-containing peptides. The conformational behavior of these peptides in their oxidized, disulfide-cyclized peptides, and reduced, linear peptides, was investigated on the basis of NMR parameters: NOEs, and 1H and 13C chemical shifts. We found that the effect of disulfide bonds on beta-hairpin stability depends on its location within the beta-hairpin structure, being very small or even destabilizing when connecting two hydrogen-bonded facing residues. When the disulfide bond is linking non-hydrogen-bonded facing residues, we estimated that its contribution to the free-energy change of beta-hairpin folding is approximately -1.0 kcal mol(-1). This value is larger than those reported for most beta-hairpin-stabilizing cross-strand side-chain-side-chain interactions, except for some aromatic-aromatic interactions, in particular the Trp-Trp one, and the cation-pi interaction between Trp and the non-natural methylated Arg/Lys. As disulfide bonds are frequently used to stabilize peptide conformations, our conclusions can be useful for peptide, peptidomimetic, and protein design, and may even extend to other chemical cross-links.


Asunto(s)
Disulfuros/química , Péptidos/química , Simulación por Computador , Enlace de Hidrógeno , Espectroscopía de Resonancia Magnética/métodos , Modelos Moleculares , Conformación Proteica , Pliegue de Proteína , Estructura Secundaria de Proteína , Termodinámica
12.
Aging Ment Health ; 12(2): 193-201, 2008 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-18389399

RESUMEN

OBJECTIVES: To examine the main and the stress-buffering effects of social networks on depressive symptoms among elderly Cuban men and women living in La Havana. METHOD: Information was gathered from a representative sample of the elderly population in Havana (n = 1905), as part of the SABE (Salud, Bienestary Enuejecimiento) study. Depressive symptoms were measured using the 15-item Geriatric Depression Scale. The structure and function of social networks were studied. Gender-specific multivariate logistic regressions were fitted to test the main (independent of stressors) and the stress-buffering effects (in the presence of financial strain or disabilities) on depressive symptoms. RESULTS: Social ties were associated with a lower prevalence of depressive symptoms in women and men independently of the presence of stressors. Women who were or had been married, lived in an extended family, and enjoyed balanced exchanges with relatives and children reported low prevalence of depressive symptoms. Men were less likely to report depressive symptoms if they were currently married, and did not live alone. Social networks buffered the effect of financial strain on depression, but not in the event of disability. CONCLUSION: In Cuba, networks centered on children and extended family were associated with low frequency of depressive symptoms, ruling contrary to common findings in developed societies. These living arrangements have an important role in buffering the impact of financial strain on depressive symptoms.


Asunto(s)
Depresión/epidemiología , Apoyo Social , Actividades Cotidianas , Anciano , Áreas de Influencia de Salud , Trastornos del Conocimiento/diagnóstico , Trastornos del Conocimiento/epidemiología , Cuba/epidemiología , Depresión/psicología , Femenino , Humanos , Persona de Mediana Edad , Pruebas Neuropsicológicas , Prevalencia
13.
Rev Panam Salud Publica ; 15(3): 176-84, 2004 Mar.
Artículo en Español | MEDLINE | ID: mdl-15096290

RESUMEN

OBJECTIVES: To look at the individual features of three different methods used to estimate simple parameters--means, totals, and percentages, as well as their standard errors--and of logistic regression models, and to describe how such methods can be used for analyzing data obtained from complex samples. METHODS: Data from Cuba's Second National Survey of Risk Factors and Non-Communicable Chronic Ailments [Segunda Encuesta Nacional de Factores de Riesgo y Afecciones Crónicas No Transmisibles], which was conducted in 2001, were studied. A complex, stratified multi-stage cluster sampling design was used. Cuba's 14 provinces and the municipality of Isla de la Juventud served as the strata, while the clusters consisted of sampled geographic areas (SGA), blocks, and sectors. Samples were weighted in inverse proportion to their probability of being selected, and estimates were performed by sex and age group (15-34, 35-54, 55-74, and 75 or more years). Taylor approximations were used to estimate variances. Three statistical methods were compared: conventional analysis, which assumes all data were obtained through simple random sampling; weighted analysis, which only takes into account the weight of the samples when performing estimates; and adjusted analysis, which looks at all aspects of the sampling design (namely, the disparity in the probability of being included in the sample and the effect of clustering on the data). RESULTS: The point estimates obtained with the three different types of analytic methods were similar. Standard error (SE) estimates for the prevalence of overweight and of arterial hypertension that were obtained by conventional analysis were underestimated by 19.3% and by more than 11.5%, respectively, when such estimates were compared to those obtained with the other two analytic methods. On the other hand, weighted analysis generated SE values that were much smaller than those obtained with the other two types of analyses. The same pattern was noted when odds ratios were calculated using the different methods. CONCLUSIONS: Analytic methods that take into account the way the data are structured as well as the study design give a more realistic picture of the problem under study and provide more exact estimates of the study parameters and their SE than conventional analytic methods. Because data from epidemiologic and public health research are often obtained through complex sampling designs, the methods described in this paper and the statistical packages that utilize them should be used more widely.


Asunto(s)
Encuestas Epidemiológicas , Proyectos de Investigación , Cuba , Tamaño de la Muestra
14.
VozAndes ; 17(1): 46-49, 2006.
Artículo en Español | LILACS | ID: biblio-1100708

RESUMEN

La membrana Pre- pilórica es una malformación es una malformación congénita poco frecuente que se asocia a vómito progresivo y alteraciones en el peso y la talla es importante definir que el vómito puede tener múltiples orígenes entre los cuales tenemos: técnica defectuosa de la alimentación, infecciones, entidades neurológicas, endocrinol{ogicas, renales, etc. lo que hace indispensable manejar una historia clínica minuciosa. Se evidencia la gran capacidad de hemeorresis del ser humano que pese a no recibir el aporte nutricional adecuado, se adapta a las circunstancias creando una nueva curva de crecimiento muy por debajo de lo normal pero paralela. Se presenta la evolución de un paciente masculino con Membrana Pre-pilórica tratado quirúrgicamente a los 6 años 8 meses de edad, determinándose la historia natural de la patología, su diagnóstico diferencial y las consecuencias pondo estaturales que pueden cursar sin dar alteraciones concurrentes del desarrollo psicomotor, como en éste caso. Conclusión: El vómito progresivo asociado a deterioro pondo-estatural en neonatos y lactantes deben estudiarse detalladamente debido a que su etiología puede ser secundaria a múltiples patologías.


The Pyloric membrane is a malformation is a rare congenital malformation that is associated with progressive vomiting and changes in weight and height, it is important to define that vomiting can have multiple origins, among which we have: defective feeding technique, infections , neurological entities, endocrinol {ogicas, renal, etc. which makes it essential to manage a thorough medical history. It is evident the great capacity of hemeorresis of the human being that despite not receiving the adequate nutritional contribution, adapts to the circumstances creating a new growth curve well below normal but parallel. The evolution of a male patient with a Pre-pyloric Membrane treated surgically at 6 years 8 months of age is presented, determining the natural history of the pathology, its differential diagnosis and the post-statural consequences that can occur without giving concurrent alterations of psychomotor development. , as in this case. Conclusion: Progressive vomiting associated with fundus-statural impairment in neonates and infants should be studied in detail because its etiology may be secondary to multiple pathologies.


Asunto(s)
Humanos , Niño , Anomalías Congénitas , Peso por Estatura , Desnutrición , Vómitos , Trastornos de Alimentación y de la Ingestión de Alimentos , Obstrucción de la Salida Gástrica
15.
Rev. panam. salud pública ; 7(4): 249-254, abr. 2000. tab
Artículo en Español | LILACS | ID: lil-264873

RESUMEN

Se presenta una comparación de las tasas de participación y de las razones de la falta de respuesta en encuestas realizadas en cinco países de América Latina y el Caribe con el objetivo de medir la prevalencia de comportamientos de riesgo que determinan la transmisión del virus de la inmunodeficiencia humana. Dichas encuestas se basaron en muestras probabilísticas de la población de ambos sexos comprendida entre 15 y 49 años de edad, excepto en México, donde se estudió solo a los hombres. Se estimaron tres componentes de la participación: las proporciones de viviendas entrevistadas, de viviendas entrevistadas con personas elegibles y de personas elegibles que cumplimentaron la entrevista. Además, se calculó un índice global que combinaba los tres componentes. La tasa global de respuesta osciló entre 35,6 por ciento en México y 81,4 por ciento en Chile, y el componente de esta tasa con mayor variabilidad fue la participación de personas elegibles, que varió entre 50 por ciento en México y 95 por ciento en Cuba. Estos valores fueron más bajos de lo esperado, sobre todo en los hombres, y servirán de orientación para futuras encuestas, ya que se deberán considerar tasas de rechazo mayores de las previstas en el protocolo. Los resultados permiten inferir la validez de las estimaciones de la prevalencia de los diversos comportamientos de riesgo observados y establecen una referencia para calcular el tamaño muestral de futuras encuestas y mejorar la metodología de la investigación


This study compares participation rates and reasons for nonresponse in surveys conducted in five countries of Latin America and the Caribbean. The objective of the surveys was to measure the prevalence of risk behaviors affecting the transmission of human immunodeficiency virus. The surveys were based on probability samples of the population of both sexes between 15 and 49 years old, except in Mexico, where only men were included. Proportions of three components of participation were estimated: residences interviewed, interviewed residences with eligible persons, and eligible persons who completed the interview. In addition, an overall index that combined the three components was calculated. The overall response rate ranged from 35.6% in Mexico to 81.4% in Chile. The component with the greatest variability was the participation of eligible persons, which ranged from 50% in Mexico to 95% in Cuba. These values were lower than what had been expected, especially among men, and will serve to guide future surveys, since rejection rates higher than the ones expected in the protocol should be considered. The results make it possible to infer the validity of the prevalence estimates for the various observed risk behaviors. The results also establish a benchmark to calculate the sample size in future surveys and to improve research methodology


Asunto(s)
Humanos , Masculino , Femenino , Adolescente , Adulto , Asunción de Riesgos , Enfermedades de Transmisión Sexual , VIH , Investigación , Recolección de Datos , Salud Pública , América Latina
16.
Artículo en Español | PAHO | ID: pah-32696

RESUMEN

Se presenta una comparación de las tasas de participación y de las razones de la falta de respuesta en encuestas realizadas en cinco países de América Latina y el Caribe con el objetivo de medir la prevalencia de comportamientos de riesgo que determinan la transmisión del virus de la inmunodeficiencia humana. Dichas encuestas se basaron en muestras probabilísticas de la población de ambos sexos comprendida entre 15 y 49 años de edad, excepto en México, donde se estudió solo a los hombres. Se estimaron tres componentes de la participación: las proporciones de viviendas entrevistadas, de viviendas entrevistadas con personas elegibles y de personas elegibles que cumplimentaron la entrevista. Además, se calculó un índice global que combinaba los tres componentes. La tasa global de respuesta osciló entre 35,6 por ciento en México y 81,4 por ciento en Chile, y el componente de esta tasa con mayor variabilidad fue la participación de personas elegibles, que varió entre 50 por ciento en México y 95 por ciento en Cuba. Estos valores fueron más bajos de lo esperado, sobre todo en los hombres, y servirán de orientación para futuras encuestas, ya que se deberán considerar tasas de rechazo mayores de las previstas en el protocolo. Los resultados permiten inferir la validez de las estimaciones de la prevalencia de los diversos comportamientos de riesgo observados y establecen una referencia para calcular el tamaño muestral de futuras encuestas y mejorar la metodología de la investigación


Asunto(s)
Investigación , Salud Pública , Recolección de Datos/estadística & datos numéricos , Asunción de Riesgos , Enfermedades de Transmisión Sexual , VIH , América Latina
17.
Rev. panam. salud pública ; 15(3): 176-184, Mar. 2004. ilus, tab
Artículo en Español | LILACS | ID: lil-363963

RESUMEN

OBJETIVOS: En el presente trabajo se discuten las particularidades de tres métodos de estimación de parámetros simples -medias, totales y porcentajes, y sus respectivos errores estándar-, así como de los modelos de regresión logística, en el análisis de los datos de muestras complejas. MÉTODOS: Se tomaron los datos de la Segunda Encuesta Nacional de Factores de Riesgo y Afecciones Crónicas No Transmisibles, realizada en Cuba en el año 2001. Se usó un diseño muestral complejo estratificado y por conglomerados polietápicos. Los estratos estuvieron conformados por las 14 provincias de Cuba y el municipio especial Isla de la Juventud, mientras que los conglomerados fueron las áreas geográficas muestrales (AGEM), manzanas y secciones. Las muestras se ponderaron en proporción inversa a las probabilidades de selección y para la estimación se realizó una estratificación por sexo y grupo de edad (15-34, 35-54, 55-74 y 75 años o más). Las varianzas se estimaron mediante las aproximaciones de Taylor. Se compararon tres métodos estadísticos: el análisis convencional, que da por sentado que los datos provienen de un muestreo simple aleatorio; el análisis ponderado, que solo toma en consideración los pesos muestrales para obtener las estimaciones; y el análisis con ajustes, que toma en cuenta la desigualdad en las probabilidades de selección y el efecto de la conglomeración en los datos. RESULTADOS: Las estimaciones puntuales obtenidas mediante las tres estrategias de análisis fueron similares. Los errores estándar estimados para la prevalencia de sobrepeso obtenidos por el análisis convencional se subestimaron en 19,3 por ciento y para la prevalencia de hipertensión en más de 11,5 por ciento en relación con los otros métodos. El análisis ponderado generó valores de los errores estándar mucho menores que los calculados por otros métodos. Resultados similares se encontraron al estimar los valores de la razón de posibilidades. CONCLUSIONES: Los métodos de análisis que toman en cuenta la estructura de los datos y las características del diseño ofrecen una visión más realista del problema estudiado. Con ellos se obtienen estimaciones más precisas de los parámetros y de sus errores estándar. La frecuencia con que se encuentran datos procedentes de diseños muestrales complejos en estudios epidemiológicos y de salud pública exige una mayor utilización de estos métodos y de los paquetes estadísticos que los contemplan.


Asunto(s)
Encuestas Epidemiológicas , Proyectos de Investigación , Cuba , Tamaño de la Muestra
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