Pervasive Downward Bias in Estimates of Liability-Scale Heritability in Genome-wide Association Study Meta-analysis: A Simple Solution.

BACKGROUND: Single nucleotide polymorphism-based heritability is a fundamental quantity in the genetic analysis of complex traits. For case-control phenotypes, for which the continuous distribution of risk in the population is unobserved, observed-scale heritability estimates must be transformed to the more interpretable liability scale. This article describes how the field standard approach incorrectly performs the liability correction in that it does not appropriately account for variation in the proportion of cases across the cohorts comprising the meta-analysis. We propose a simple solution that incorporates cohort-specific ascertainment using the summation of effective sample sizes across cohorts. This solution is applied at the stage of single nucleotide polymorphism-based heritability estimation and does not require generating updated meta-analytic genome-wide association study summary statistics. METHODS: We began by performing a series of simulations to examine the ability of the standard approach and our proposed approach to recapture liability-scale heritability in the population. We went on to examine the differences in estimates obtained from these 2 approaches for real data for 12 major case-control genome-wide association studies of psychiatric and neurologic traits. RESULTS: We found that the field standard approach for performing the liability conversion can downwardly bias estimates by as much as approximately 50% in simulation and approximately 30% in real data. CONCLUSIONS: Prior estimates of liability-scale heritability for genome-wide association study meta-analysis may be drastically underestimated. To this end, we strongly recommend using our proposed approach of using the sum of effective sample sizes across contributing cohorts to obtain unbiased estimates.

Tetanus, analysis of 29 cases.

BACKGROUND: Tetanus disease is caused by Clostridium tetani, an anaerobe bacteria found in dust and soil. Once reached human body through damaged tissues, C. tetani releases several neurotoxins which block the inhibitory function, leading to an increased muscle tone, ultimately causing respiratory failure. Severe tetanus is a life-threatening disease, especially in low-income-regions. METHODS: This is a retrospective case-series study, undertaken at two hospitals of Vigo (population area 600,000 inhabitants). Tetanus cases were identified through the discharge databases of both hospitals between the years 1995-2019. Epidemiological and clinical data were obtained from the patient's medical records. RESULTS: A total of 33 cases were identified; median age was 67 years, and most of patients were women (n=16, 55.2%). Generalized tetanus was the most common clinical course, and neck stiffness was the most frequent symptom. A total of 25 patients (86%) were admitted to the Intensive Care Unit, 21 required invasive ventilation and 2 patients died. DISCUSSION: The incidence of tetanus was low but most of cases were severe. Mortality was slightly higher than previously reported. Interestingly, the deceased patients were old-women, consistent with previously reported research in high-income-regions, while mortality in low-income-countries concentrates in middle-aged men.

Comparing Methods for Modeling Acquiescence in Multidimensional Partially Balanced Scales / Comparación de Métodos Para Modelar la Aquiescencia en Escalas Multidimensionales Parcialmente Balanceadas

BACKGROUND: The inclusion of direct and reversed items in scales is a commonly-used strategy to control acquiescence bias. However, this is not enough to avoid the distortions produced by this response style in the structure of covariances and means of the scale in question. This simulation study provides evidence on the performance of two different procedures for modelling the influence of acquiescence bias on partially balanced multidimensional scales: a method based on exploratory factor analysis (EFA) with target rotation, and a method based on random intercept factor analysis (RIFA). METHOD: The independent variables analyzed in a simulation study were sample size, number of items per factor, balance of substantive loadings of direct and reversed items, size and heterogeneity of acquiescence loadings, and inter-factor correlation. RESULTS: The RIFA method had better performance over most of the conditions, especially for the balanced conditions, although the variance of acquiescence factor loadings had a certain impact. In relation to the EFA method, it was severely affected by a low degree of balance. CONCLUSIONS: RIFA seems the most robust approach, but EFA also remains a good alternative for medium and fully balanced scales

ANTECEDENTES: la inclusión de ítems directos e inversos en escalas es una estrategia comúnmente utilizada para controlar el sesgo de aquiescencia. No obstante, esto es insuficiente para evitar las distorsiones producidas por este estilo de respuesta en la estructura de covarianzas y medias de la escala. El presente estudio de simulación aporta evidencia sobre el rendimiento de dos procedimientos para controlar la influencia del sesgo de aquiescencia en escalas multidimensionales parcialmente balanceadas: un método basado en análisis factorial exploratorio con rotación target (EFA), y un método basado en el análisis factorial confirmatorio con intercepto aleatorio (RIFA). MÉTODO: las variables independientes del estudio de simulación fueron: tamaño muestral, número de ítems por factor, balanceo de los pesos sustantivos de los ítems directos e inversos, tamaño y heterogeneidad de los pesos en aquiescencia, y correlación entre factores. RESULTADOS: el método RIFA tiene mejor funcionamiento en general, especialmente para las condiciones balanceadas, aunque la varianza de los pesos de aquiescencia tuvo impacto en su rendimiento. El método EFA se ve principalmente afectado en la situación de bajo balanceo. CONCLUSIONES: el RIFA parece la aproximación más robusta, aunque el EFA se mantiene como una alternativa a considerar para escalas con balanceo medio o completo

Chondroid Metaplasia in a Fibroepithelial Polyp of Gingiva.

Gingival masses are commonly encountered in clinical practice and can be a result of many conditions one of them could be metaplasia. Metaplasia is defined as the replacement of the lining of an organ with the type of lining normally found at another site. We are reporting a case of a 17-year-old Mexican male who presented with a pedunculated nodule associated to maxillary anterior gingiva. The histopatological examination revealed a chondroid material covered by stratified squamous epithelium and was diagnosed as chondroid metaplasia.

Linfedema genital crónico gigante. Contribución de 2 casos, abordaje quirúrgico y revisión de la literatura / Chronic giant genital lymphedema: contribution of 2 cases, description of surgical approach and literature review

Objetivo. Exponer una descripción detallada de la técnica quirúrgica para el linfedema genital crónico gigante. Comentar otras opciones quirúrgicas de extirpación y reconstrucción. Método. Se presentan los casos de 2 varones con linfedema genital crónico gigante de más de 2 años de evolución, con gran afectación funcional y un estado de ánimo y autoestima bajos. Se realiza una descripción por pasos de la técnica quirúrgica y los cuidados posteriores. Resultados. Se realizó la extirpación completa del linfedema genital crónico gigante hasta tejido sano, la disminución de la oquedad condicionada por la extirpación, con flaps de piel y tejido celular subcutáneo, y la reparación del defecto de la piel con injertos cutáneos libres de espesor parcial obtenidos del abdomen. El resultado estético fue muy bueno y se obtuvo un magnífico resultado psicológico, con mejoría de la autoestima y el estado de ánimo. Conclusiones. El tratamiento quirúrgico en casos avanzados es la única opción posible. Con la técnica descrita se obtienen buenos resultados (estéticos, funcionales y psicológicos) (AU)

Aim. To provide a detailed description of the surgical technique for the chronic giant genital lymphedema. To explain other surgical methods of removal and reconstruction. Method. Based in 2 males with a chronic giant genital lymphedema with more than 2 years of evolution, with high functional impairment, low mood and low self-esteem. Description, step by step, of the surgical procedures and postoperative care. Results. The removal of the chronic giant genital lymphedema up to healthy tissue was performed. Reduction of the cavity conditioned by the removal, with flaps of skin and subcutaneous tissue. Repair of skin defect with partial thickness skin grafts obtained from the abdomen. Very good aesthetic result and splendid psychological outcome with improved self-esteem and mood. Conclusions. Surgical treatment in advanced cases is the only option. With the described technique good results (aesthetic, functional and psychological) are obtained (AU)

Arteritis de células gigantes con afectación del epidídimo / Giant cell arteritis with epididymal involvement

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Utilidad de la ultrasonografía introital en incontinencia de orina de esfuerzo, curva ROC / Usefulness of introital ultrasonography in stress incontinence of urine, ROC curve

Para determinar si existe una variable en ultrasonografía introital que pueda utilizarse para distinguir mujeres con incontinencia de orina de esfuerzo (IOE) y mujeres continentes, realizamos este estudio de tipo diagnóstico prospectivo de un solo centro involucrando 24 mujeres continentes y 43 mujeres con IOE todas voluntarias seleccionadas según los criterios de inclusión- exclusión, se realizó ultrasonografía introital a todas ellas consignando diversos parámetros de distancias y ángulos en reposo durante Valsalva y Kegel, de todas las variables analizadas la altura H durante Valsalva fue la mejor para distinguir entre pacientes incontinentes y continentes siendo 15.5 mm el valor de corte según la curva de ROC correspondiente.

Objective: To determine if there is a variable on introital ultrasonography (IUS) that can be used to distinguish between women with stress urinary incontinence and continent women. Patients and methods: This single centre, prospective, diagnostic study, comprised 24 women continent and 43 incontinent who were all appropriately informed volunteers selected according to the inclusion criteria. IUS with a transvaginal probe was performed on all women; the measurement plane was standardized and coordinates were obtained at rest, on straining and Kegel. Several distances and angles were measured to determine if any provided an objective distinction between continent and incontinent women. Results: Among all the IUS variables assessed, the height H (the vertical distance from a horizontal line drawn at the lower border of the symphysis and the bladder neck) on straining (Valsalva) was the best for distinguishing continent and incontinent women. The receiver operating characteristic curves showed that with a threshold of 15,5 mm, the height H on straining had a sensitivity of 70.8 percent and a specificity of 82.9 percent for detecting Stress Urinary incontinence (SUI). The sliding (calculated as the difference between the height H at rest and under stress) and the height H at rest could also discriminate, but with lower significance. Conclusions: IUS is an important tool for diagnosing SUI; there are three independent variables, one dynamic (sliding) and two static (height H at rest and straining), that can be used to distinguish between continent women and those with SUI. The height H at Valsalva is the most reliable, as it has the highest sensitivity and specificity. We think that the simplicity, low financial cost and reliability of IUS could allow it to be a routine procedure for physicians working in incontinence units.

Ecuación de Framingham de Wilson y ecuación de REGICOR. Estudio comparativo / Comparison of coronary risk estimates derived using the Framingham and REGICOR equations

Introducción y objetivos. Comparar dos ecuaciones de valoración del riesgo coronario (RC), Framingham de Wilson y REGICOR, en una muestra poblacional de sujetos dislipémicos de nuestra área sanitaria. Valorar las posibles repercusiones terapéuticas derivadas de las mediciones obtenidas por ambos métodos. Pacientes y método. La muestra poblacional estaba constituida por 815 pacientes dislipémicos de 35-74 años. Se determinó el RC mediante ambas ecuaciones y se compararon las puntuaciones obtenidas, la clasificación en las categorías de RC a los 10 años y el número de sujetos potencialmente tratables con medicación hipolipemiante en función de los resultados obtenidos con ambas escalas. Resultados. Se observó una óptima correlación entre ambas mediciones al tener en cuenta los valores cuantitativos (r = 0,983; p < 0,001), aunque ésta disminuyó al valorar los resultados por categorías de RC (p = 0,489; p < 0,001). La concordancia fue mala en su conjunto (κ = 0,06) y sólo fue aceptable en el grupo de riesgo bajo (κ = 0,53). La tabla de Wilson proporcionó unos valores de RC global 2,4 veces superiores a los obtenidos con la calibración de REGICOR, y las diferencias se presentaran principalmente en las categorías de RC moderado y alto. El número de candidatos a ser tratados con hipolipemiantes fue 5 veces superior según la ecuación de Wilson que con la de REGICOR. Conclusiones. La sobrevaloración que se obtiene al calcular el RC mediante la función de Framingham implica un mayor porcentaje de pacientes potencialmente tratables con fármacos hipolipemiantes. Este hecho apoya la necesidad de disponer de tablas de RC ajustadas para nuestra población

Introduction and objectives. To compare two equations for evaluating coronary risk, the Framingham-Wilson equation and the Framingham equation adjusted for the Spanish population (REGICOR), in a group of dyslipidemic patients in our healthcare area. In addition, the therapeutic implications of using the 2 methods were also evaluated. Patients and method. The study included 815 dyslipidemic patients, aged 35-74 years, from our healthcare area. Coronary risk was determined using the 2 equations and subjects were categorized as either low-risk (0%- 9%), moderate-risk (10%-19%), or high-risk (≥20%). To compare the application of the 2 equations, we evaluated differences in derived scores, coronary risk category, and the number of patients regarded as potentially treatable with hypolipidemic drugs. Results. The best correlation observed between the 2 methods was for quantitative scores (r=0.983; P<.001). The correlation was poorer when coronary risk categories were compared (r=0.489; P<.001). Overall, the concordance was poor (κ=0.06), and was only acceptable for low-risk patients (κ=0.53). The coronary risk estimates derived from the Wilson table were 2.4 times higher than those obtained using REGICOR. The main differences were for moderate and high-risk patients. In addition, the number of patients regarded as potentially treatable with hypolipidemic drugs was five times higher when the Wilson equation was used. Conclusions. The overestimate of coronary risk obtained using the Framingham-Wilson equation leads to a greater number of patients being regarded as candidates for hypolipidemic treatment. Our data show the importance of using tables adjusted for the Spanish population