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El reflujo gastroesofágico (RGE) es el paso fisiológico del contenido gástrico hacia el esófago, presente en condiciones normales a cualquier edad y es uno de los problemas gastrointestinales más comunes en niños. El estado nutricional es adecuado y muchas veces por arriba de los percentiles de peso y talla y es un niño “vomitador feliz”. En cambio, la enfermedad por reflujo gastroesofágico (ERGE) está asociada con síntomas molestos respiratorios, digestivos, trastornos durante el sueño, lesiones dentales las que en un gran número de casos pasan desapercibidas y son notadas hasta que han causado un daño significativo y pueden ir desde prurito, ardor de mucosa, aumento de la sensibilidad dental y lingual, sabor amargo, erosiones hasta caries dental, estas cumplen un importante papel en la edad pediátrica, sobre todo cuando el niño presenta trastornos en las funciones neurosensoriales, motoras, como daño neurológico secundario a encefalopatía hipóxico isquémica, defectos del tubo neural, atresia esofágica y enfermedades degenerativas. Dentro de las complicaciones de ERGE cabe resaltar neumonía por broncoaspiración, otitis, faringoamigdalitis, crup y compromiso en el estado nutricional. La ERGE tiene gran importancia médica y social debido al incremento en su incidencia y a los síntomas duraderos ya que reducen la calidad de vida. La habilidad de poder distinguir entre las manifestaciones clínicas de RGE y ERGE en los diferentes grupos etarios nos permite identificar que pacientes deben ser extensamente evaluados y manejados con tratamiento conservador o si estos requieren ser derivados al odontólogo pediatra. Debido a que existe desconocimiento acerca de las lesiones dentales que se producen en la ERGE decidimos hacer la presente revisión ya que es muy importante que el personal de salud: estudiantes, médicos y odontólogos sean capaces de identificar, diagnosticar e implementar recomendaciones apropiadas, dar tratamiento específico tanto desde el punto de vista médico como dental dadas las repercusiones que esta conlleva y así derivar oportunamente.

Nanotechnology has developed rapidly in the last two decades with significant effort focused on the development of nano-enabled materials with new or improved properties that offer solutions for current world challenges. The commercialization of products containing engineered nanomaterials (ENM) has progressed much more rapidly than the development of practical approaches to ensure their safe and sustainable use. The lack of adequate detection and characterization techniques and reproducible and validated methods for toxicological studies have been identified as major limitations. The rapid development of ENM of increasing complexity and diversity and concerns over the adequacy of existing regulations also contribute to safety concerns with these materials. The full potential of nanotechnology can only be realized when feasible, cost-effective strategies to ensure a safe-by-design approach, effective risk assessment approaches and appropriate regulatory guidelines are in place.

Mean sensitivity (MS) derived from a standard test grid using microperimetry is a sensitive outcome measure in clinical trials investigating new treatments for degenerative retinal diseases. This study hypothesizes that the functional decline is faster at the edge of the dense scotoma (eMS) than by using the overall MS.Multicenter, international, prospective cohort study: ProgStar Study.Stargardt disease type 1 patients (carrying at least 1 mutation in the ABCA4 gene) were followed over 12 months using microperimetry with a Humphrey 10-2 test grid. Customized software was developed to automatically define and selectively follow the test points directly adjacent to the dense scotoma points and to calculate their mean sensitivity (eMS).Among 361 eyes (185 patients), the mean age was 32.9 ± 15.1 years old. At baseline, MS was 10.4 ± 5.2 dB (n = 361), and the eMS was 9.3 ± 3.3 dB (n = 335). The yearly progression rate of MS (1.5 ± 2.1 dB/year) was significantly lower (β = -1.33; P.001) than that for eMS (2.9 ± 2.9 dB/year). There were no differences between progression rates using automated grading and those using manual grading (β = .09; P = .461).In Stargardt disease type 1, macular sensitivity declines significantly faster at the edge of the dense scotoma than in the overall test grid. An automated, time-efficient approach for extracting and grading eMS is possible and appears valid. Thus, eMS offers a valuable tool and sensitive outcome parameter with which to follow Stargardt patients in clinical trials, allowing clinical trial designs with shorter duration and/or smaller cohorts.

The development of reliable and practical tools to ensure the safe and sustainable use of nanomaterials has not kept pace with the rapid commercialization of nanotechnology-enabled products. Here we present an overview of some of the current challenges and opportunities for the evaluation of the safety of engineered nanomaterials (ENM), based on input from an IUPAC (International Union of Pure and Applied Chemistry) sponsored workshop in Queretaro, Mexico. The workshop covered detection and characterization of ENM, their transformations in consumer products and the environment, current gaps in nanotoxicology methods and challenges for standardization and risk assessment. Key future research priorities include developing methods to detect and characterize ENM in complex matrices and determinations of their transformations in such environments. The extension of methods to more challenging materials such as complex or advanced nanomaterials and carbon-based materials is also needed. Furthermore, an increased availability of validated protocols and reference materials will be necessary to advance both nanosafety studies and material characterization. A focus on accurate dosimetry, appropriate control experiments and more realistic in vitro models will help to address current gaps in nanotoxicology. Finally, there is an urgent need for reliable data and improved data reporting guidelines, supported by computational modeling, in order to allow the development of grouping and read across methods.

Purpose To investigate the natural history of Stargardt disease (STGD1) using fixation location and fixation stability. Design Multicenter, international, prospective cohort study. Methods Fixation testing was performed using the Nidek MP-1 microperimeter as part of the prospective, multicenter, natural history study on the Prog ression of Star gardt disease (ProgStar). A total of 238 patients with ABCA4-related STGD1 were enrolled at baseline (bilateral enrollment in 86.6%) and underwent repeat testing at months 6 and 12. Results Outcome measures included the distance of the preferred retinal locus from the fovea (PRL) and the bivariate contour ellipse area (BCEA). After 12 months of follow-up, the change in the eccentricity of the PRL from the anatomic fovea was −0.0014 degrees (95% confidence interval [CI], −0.27 degrees, 0.27 degrees; P = .99). The deterioration in the stability of fixation as expressed by a larger BCEA encompassing 1 standard deviation of all fixation points was 1.21 degrees squared (deg2) (95% CI, −1.23 deg2, 3.65 deg2; P = .33). Eyes with increases and decreases in PRL eccentricity and/or BCEA values were observed. Conclusions Our observations point to the complexity of fixation parameters. The association of increasingly eccentric and unstable fixation with longer disease duration that is typically found in cross-sectional studies may be countered within individual patients by poorly understood processes like neuronal adaptation. Nevertheless, fixation parameters may serve as useful secondary outcome parameters in selected cases and for counseling patients to explain changes to their visual functionality.

In complement dependent cytotoxicity crossmatch negative renal transplant candidates with human leukocyte antigen donor-specific antibodies (DSA), both the presence of DSA C1q+ and the dominant DSA fluorescence were significantly associated with a positive flow cytometry crossmatch (FXM+). The C1q+ assay was highly specific, but had low sensitivity when predicting FXM+, so the clinical significance of a FXM+ in the absence of DSA C1q+ remains to be clarified in future studies.

To examine the association between characteristics of Stargardt disease and visual acuity (VA), to estimate the longitudinal rate of VA loss, and to identify risk factors for VA loss.Retrospective, multicenter cohort study.A total of 176 patients (332 eyes) with molecularly and clinically confirmed Stargardt disease enrolled from the United States and Europe.Standardized data report forms were used to collect retrospective data on participants' characteristics and best-corrected or presenting VA from medical charts. Linear models with generalized estimating equations were used to estimate the cross-sectional associations, and linear mixed effects models were used to estimate the longitudinal VA loss.Yearly change in VA.The median duration of observation was 3.6 years. At baseline, older age of symptom onset was associated with better VA, and a longer duration of symptoms was associated with worse VA. Longitudinal analysis estimated an average of 0.3 lines loss (P0.0001) per year overall, but the rate varied according to baseline VA: (1) eyes with baseline VA ≥20/25 (N = 53) declined at a rate of approximately 1.0 line per year; (2) eyes with VA between 20/25 and 20/70 (N = 65) declined at a rate of approximately 0.9 lines per year; (3) eyes with VA between 20/70 and 20/200 (N = 163) declined at a rate of 0.2 lines per year; and (4) eyes with VA worse than 20/200 (n = 49) improved at a rate of 0.5 lines per year. Older age of onset was associated with slower VA loss: Patients with onset age30 years showed 0.4 lines slower change of VA per year (P = 0.01) compared with patients with onset age ≤14 years.Given the overall slow rate of VA loss, VA is unlikely to be a sensitive outcome measure for treatment trials of Stargardt disease. However, given the faster decline in younger patients and those with no or mild visual impairment, VA may be a potential outcome measure for trials targeting such subgroups of patients. These observations will need to be assessed in a prospective study bearing in mind the inherent limitations of retrospective datasets.

Two trials were performed in Balcarce, Argentina (37° 45' LS; 58° 18' LW) during 1993-94, to assess the effect of eight herbicides applied individually or in tank mixtures, on nodule number, nodule dry weight, seed yield and N percent in seed in soybean Asgrow 3205, inoculated with Bradyrhizobium japonicum CB 1809. Individual herbicides and doses in kg ha-1 of a.i. were metribuzin (0.48), acetochlor (0.90), metolachlor (1), flumioxazin (0.075), trifluralin (0.96), imazaquin (0.20), imazethapyr (0.10) and chlorimuron ethyl (0.0125). The mixtures were metribuzin+acetochlor (0.48+0.9), flumioxazin+acetochlor (0.075+0.9), imazaquin+acetochlor (0.2+0.9), metribuzin+metolachlor (0.48+1.92), and flumioxazin+ metolachlor (0.075+1.92). A control treatment without herbicides was included. Both trials were laid out as randomized complete blocks with four replicates, on a loam illitic thermic petrocalcic Paleudoll, 5.7% organic matter (OM), 25% clay, 30.4 cmol kg-1 CEC. Nodules were sampled at V2 (second node), V6 (sixth node) and R5 (beginning seed) growth stages. Herbicides did not significantly affect the beginning of nodulation or nodule number and mass at R5, not either grain yield or N accumulation. This indicates lack of interference between soil interacting herbicides and N fixation in the high organic matter, loam soils of SE Buenos Aires province, even though a tendency in less number and dry weight of nodules was evident at the two latter growth stages. Durante 1993-94 realizaram-se dois experimentos em Balcarce, Argentina (37° 45' LS; 58° 18' LO) para avaliar o efeito de oito herbicidas, aplicados isoladamente ou em misturas, sobre o número e peso de nódulos, rendimento e percentagem de N nos grãos de soja Asgrow 3205 que receberam inoculação da estirpe CB1809 de Bradyrhizobium japonicum. Os herbicidas aplicados isoladamente e suas doses em kg ha-1 de i.a. foram metribuzin (0,48), acetochlor (0,90), metolachlor (1), flumioxazin (0,075), trifluralin (0,96), imazaquin (0,20), imazathapyr (0,10) e chlorimuron ethyl (0,0125). As misturas foram metribuzin+acetochlor (0,48+0,9), flumioxazin+acetochlor (0,075+0,9), imazaquin+acetochlor (0,2+0,9), metribuzin+metolachlor (0,48+1,92), e flumioxazin+metolachlor (0,075+1,92). Incluiu-se um controle sem herbicidas. Os experimentos foram conduzidos no delineamento em blocos completos ao acaso, com quatro repetições. Usou-se um solo Paleudol petrocálcico, franco, ilítico, térmico, com matéria orgânica 5,7%, argila 25%, e CTC 30,4 cmol kg-1. Os nódulos foram amostrados em V2 (segundo nó), V6 (sexto nó) e R5 (começo de semente). Os herbicidas não alteraram o início da nodulação nem o número ou peso dos nódulos em R5, e também não houve efeito no rendimento de grãos, o que sugere que não há interferência entre eles e fixação de N nos solos francos com alto conteúdo de matéria orgânica do sudeste de Buenos Aires. Por outro lado, evidenciou-se uma tendência à formação de menos nódulos e menor peso dos nódulos, nos dois últimos níveis de crescimento.

El presente documento remite a un tema de cada vez mayor actualidad, tanto si la referenciaes a México como si se aborda el ámbito internacional: el estrés laboral , entendido como ese proceso de desgaste mental y cognitivo que, invariablemente, hoy en día parece ser un acompañante intrínseco a la jornada laboral (y más allá de ella abarcando las diferentes esferas de la vida cotidiana). Éste debe ser planteado y analizado bajo una óptica diferente al énfasis puesto en torno a la preocupación por la medición, la caracterización, la evaluación,el desarrollo de modelos para el control del estrés laboral, entre lo más destacado; pero con un profundo descuido respecto a la base de su discusión, construcción y definición históricasocial, vertiente en torno a la cual se desarrolla el presente ensayo, en el que además de las pistas de análisis e investigación expuestas, se lleva a cabo un trabajo de aproximación e interpretación histórico social, del que se destacan las narrativas de médicos del primer nivel de atención, adscritos a la Secretaría de Salud (SSA).

Los cambios que en la organización de los sistemas de salud se han venido registrando en el mundo, han tenido un particular impacto en la manera en que se ofrece la atención a pacientes que recurren a los servicios del primer nivel, proporcionados por instituciones encargadas de prestar atención a población abierta, como lo es el caso del Instituto de Salud del Estado de México. Así, el presente documento se propone llevar a cabo una primera descripción y análisis de la transformación de los servicios de salud, de cara a un modelo de atención biomédica que enfrenta graves dificultades para responder a las necesidades de la población; en el caso que nos ocupa, en lo que corresponde a la atención de pacientes diabéticos no insulino dependientes. Todo ello en el marco de la retórica de cambio que pretendió justificar una reforma en el ámbito de la salud, a juego con las expectativas generadas por el proceso de descentralización de un sector que es clave para el desarrollo de cualquier sociedad.

En el presente documento, se realiza una aproximación históricocontextual que invita a pensar en la #147;atención médica #148;, y en la relación que el médico mantiene con el paciente, desde una posición crítica; para ello se hace referencia a tres momentos de la historia: la etapa grecohipocrática, la Edad Media y la llamada #147;sociedad moderna #148;, en los que con referentes muy particulares se recrean condiciones que dan origen a figuras específicas que atienden el padecimiento físico y corporal tenido como tal en cada época, y que vale la pena recordar. Para los dos primeros casos no se plantea lo que hoy conocemos como descripción y diagnóstico clínico. Así, en el marco de la crítica a los fundamentos y valores occidentales, el planteamiento de una aproximaci ón a los orígenes de la #147;atención médica #148; como parte de la cultura y de la razón del llamado mundo moderno, nos ayuda a entender y a diferenciar la presencia y desenvolvimiento de una actuación médica vinculada desde sus orígenes con los planteamientos biomédicos en torno al llamado proceso salud-enfermedad.

El objetivo del presente documento es recuperar parte del marco en que se ha desenvuelto la epidemiología social en la política sanitaria del país, así como sus retos y expectativas frente a los importantes cambios que se están registrando en torno al papel y funciones de los sistemas de salud en México y, en general, en el ámbito latinoamericano. En este sentido, hablamos de la salud como una de las problemáticas que más impactan la existencia y convivencia al interior de una población, presentándose como causa y efecto de las relaciones sociales que ahí se desarrollan.

Under the auspices of the Organic Analysis Working Group (OAWG) of the Comit? Consultatif pour la Quantit? de Mati?re (CCQM) a key comparison, CCQM K55.b, was coordinated by the Bureau International des Poids et Mesures (BIPM) in 2010/2011. Nineteen national measurement institutes and the BIPM participated. Participants were required to assign the mass fraction of aldrin present as the main component in the comparison sample for CCQM-K55.b which consisted of technical grade aldrin obtained from the National Measurement Institute Australia that had been subject to serial recrystallization and drying prior to sub-division into the units supplied for the comparison. Aldrin was selected to be representative of the performance of a laboratory's measurement capability for the purity assignment of organic compounds of medium structural complexity [molar mass range 300 Da to 500 Da] and low polarity (pKOW < ?2) for which related structure impurities can be quantified by capillary gas phase chromatography (GC). The key comparison reference value (KCRV) for the aldrin content of the material was 950.8 mg/g with a combined standard uncertainty of 0.85 mg/g. The KCRV was assigned by combination of KCRVs assigned by consensus from participant results for each orthogonal impurity class. The relative expanded uncertainties reported by laboratories having results consistent with the KCRV ranged from 0.3% to 0.6% using a mass balance approach and 0.5% to 1% using a qNMR method. The major analytical challenge posed by the material proved to be the detection and quantification of a significant amount of oligomeric organic material within the sample and most participants relying on a mass balance approach displayed a positive bias relative to the KCRV (overestimation of aldrin content) in excess of 10 mg/g due to not having adequate procedures in place to detect and quantify the non-volatile content?specifically the non-volatile organics content?of the comparison sample. There was in general excellent agreement between participants in the identification and the quantification of the total and individual related structure impurities, water content and the residual solvent content of the sample. The comparison demonstrated the utility of 1H NMR as an independent method for quantitative analysis of high purity compounds. In discussion of the participant results it was noted that while several had access to qNMR estimates for the aldrin content that were inconsistent with their mass balance determination they decided to accept the mass balance result and assumed a hidden bias in their NMR data. By contrast, laboratories that placed greater confidence in their qNMR result were able to resolve the discrepancy through additional studies that provided evidence of the presence of non-volatile organic impurity at the requisite level to bring their mass balance and qNMR estimates into agreement. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Filosofia e Ciências Humanas.

The aim of the present study was to evaluate the frequency of HLA-A and HLA-B antigens in a sample of the Mexico City Mestizo population. Previous similar studies were done by other authors in nonrelated individuals, while the present investigation was performed in families (parents and offspring), and therefore, a more accurate estimate of gene and haplotype frequencies was obtained. The predominant antigens in descending order are A2, A24, and A28 at the A locus, whereas B39 and B35 are at the B locus, all with gene frequencies above 0.1. As expected, the two more frequent haplotypes were A2-B16 and A2-B35 (considering main specificities), both with frequencies of 0.056. Seven of the 18 significant delta values of the haplotypes (observed vs. expected) remained significant after correcting for the number of comparisons, indicating the presence of linkage disequilibrium between the HLA-A and HLA-B regions. However, only A1-B8 and A19-B13 were found to be in disequilibrium in another Mexico City Mestizo sample which had very similar HLA-A and HLA-B allele frequencies to those in the present survey, suggesting that the biological significance of the other associations is rather doubtful. Am. J. Hum. Biol. 9:1-5 © 1997 Wiley-Liss, Inc.

El objetivo del documento es destacar el peso que tiene la enseñanza de la investigación en el nivel licenciatura, donde el estudiante universitario adquiere las bases de su trabajo profesional y de su presencia intelectual; en este sentido, se toma el caso de la Facultad de Ciencias Políticas y Administración Pública de la Universidad Autónoma del Estado de México, en torno al cual se hacen algunas puntualizaciones, que de manera genérica destacan la importancia de repensar el modelo docente actual que aproxima la investigación (como campo de conocimiento y práctica profesional) a los alumnos de licenciatura.

En México, la llamada teoría de la transición epidemiológica ha sido y sigue siendo un punto de referencia en el campo de la investigación, y desde luego en el ámbito gubernamental ante la necesidad de comprender y de explicar, en su caso de actuar, en torno a los cambios en los patrones de salud y de enfermedad que se registran en el país hacia la segunda mitad del siglo XX; sin embargo, dada la complejidad que han alcanzado nuestras sociedades, el sentido de una inevitable transición en salud que marca la diferencia entre sociedades subdesarrolladas y desarrolladas, se encuentra en entredicho, por lo que se vuelve urgente replantear la vigencia y los alcances de esta teoría para generar políticas en salud viables y en consecuencia con un favorable impacto en el complejo y diverso panorama de la salud.