Síndrome de las plaquetas pegajosas, la condición de trombofilia heredada más frecuente en pacientes mexicanos

Antecedentes: el síndrome de las plaquetas pegajosas supone trastornos en la agregabilidad de las plaquetas, caracterizados por incremento anormal de las mismas y tendencia a fenómenos vasoclusivos, arteriales y venosos. El mecanismo patogénico no se conoce; su existencia sólo puede determinarse con las pruebas de agregación plaquetaria. Su prevalencia tampoco se conoce pero hay datos que sugieren que es frecuente. Algunos autores opinan que es responsable de 20% de las trombosis arteriales inexplicables y de 13% de las venosas en las que no es posible identificar una causa. Objetivos: revisar la información disponible sobre el síndrome de las plaquetas pegajosas y su trascendencia en México. Conclusiones: el síndrome de las plaquetas pegajosas es la condición de trombofi lia más frecuente en México. Existen pocos reportes de la evaluación clínica de pacientes mexicanos, lo que hace imperativo realizar estudios prospectivos rigurosos para establecer su magnitud

Factores que afectan algunas de las pruebas del tamiz neonatal

Introducción: los métodos analíticos del tamiz metabólico, adaptados al estudio de sangre impregnada en un papel fi ltro, pueden afectarse por factores externos que alteran falsamente los resultados. Objetivo: identificar los factores que afectan las pruebas y el control de calidad del tamiz neonatal. Material y métodos: se realizó análisis retrospectivo y observacional, desde junio del 2002 hasta octubre del 2004, y se estudió el tamiz neonatal de 632 pacientes para identificar los factores que alteran los resultados y determinar cuáles son las pruebas más susceptibles. Se evaluó la calidad de la muestra, y las condiciones de almacenamiento y transporte. Resultados: entre los 632 estudios, en 42 pacientes (6.6%) estuvieron alterados uno o varios de los analitos; en 11 de estos últimos (1.7% del total y 26% de los estudios con resultados anormales) se comprobó un defecto metabólico y en los restantes 31 alguna interferencia. Las pruebas más susceptibles al efecto de la interferencia fueron glucosa-6-fosfato deshidrogenasa (13 casos), uridil galactosa transferasa (nueve casos) y tripsinógeno inmunoreactivo (cinco casos). Las causas más frecuentes de interferencia fueron muestras mal conservadas y administración de medicamentos anticonvulsivantes (ácido valproico). Discusión: la elevada frecuencia de resultados falsos positivos en el tamiz neonatal hace imperativo establecer acciones preventivas para disminuir el número de muestras rechazadas y obliga a descartar las fuentes comunes de interferencia antes de emitir algún diagnóstico presuntivo

Investigación de las mutaciones Leiden del factor V y G20210A de la protrombina en pacientes pediátricos con hemofilia A grave: informe preliminar

Introducción: Se ha descrito que las características clínicas de la hemofilia A grave se ven modificadas favorablemente por el efecto de factores protrombóticos, específicamente las mutaciones Leiden del factor V y la G20210A de la protrombina. Pacientes y métodos: Se estudiaron 13 pacientes con diagnóstico de hemofilia A grave en quienes se investigó la presencia de las mutaciones: Leiden del factor V y la G20210A de la protrombina por medio de reacción en cadena de la polimerasa en tiempo real. Resultados: Al investigar la presencia de las mutaciones todos los pacientes presentaron el genotipo homocigoto normal para las mutaciones Leiden del factor V y la G20210A de la protrombina. Conclusiones: estos 13 pacientes son el inicio de una línea de investigación que tiene como finalidad conocer los cambios que se producen en los pacientes con hemofilia A grave que son también portadores de factores protrombóticos, es necesario incrementar el número de pacientes para obtener la frecuencia de dichas mutaciones en los pacientes con hemofilia grave

Vitamin D levels in the pre- and post-COVID-19 pandemic periods in pediatric patients with chronic kidney disease

IntroductionVitamin D (VD) deficiency is common in children with chronic kidney disease (CKD) because of multiple factors. During the coronavirus disease 2019 (COVID-19) pandemic, it increased because of medicine shortage and no enough medical service for patients with non-COVID-19 diseases.ObjectiveTo analyze the effects of the COVID-19 pandemic-related lockdown on the serum levels and status of 25-hydroxyvitamin D3 (25-[OH]D) in children with CKD.Materials and methodsThis retrospective study included patients (6–18 years old) who were diagnosed with CKD stage 2–5 and routinely measured for serum VD levels between May 2019 and December 2022. Serum 25-(OH)D levels were measured before, during, and after the pandemic (2019, 2020–2021, and 2022, respectively). The daily dose of cholecalciferol supplementation and the readjustment (if required) were recorded.ResultsThis study included 171 patients (median age: 12 years). Before the pandemic, the median serum VD level was 25.0 ng/mL (19.3% VD deficiency). Then, VD supplementation was adjusted to 400–1,200 UI daily in 98.8% (n = 169) of patients. During the pandemic, the median VD level decreased to 22.5 ng/mL (43.3% VD deficiency). Hence, the supplementation was readjusted, and after the pandemic, the level was 28.7 ng/mL (18.7% VD deficiency), indicating a statistically significant increase in serum VD levels from the prepandemic period (p = 0.007).ConclusionDecreased serum VD levels and increased VD deficiency frequency were observed in patients with CKD during the COVID-19 but improved after readjustment of supplementation

Whole-Genome Sequences of Five Acinetobacter baumannii Strains From a Child With Leukemia M2

Acinetobacter baumannii is an opportunistic pathogen and is one of the primary etiological agents of healthcare-associated infections (HAIs). A. baumannii infections are difficult to treat due to the intrinsic and acquired antibiotic resistance of strains of this bacterium, which frequently limits therapeutic options. In this study, five A. baumannii strains (810CP, 433H, 434H, 483H, and A-2), all of which were isolated from a child with leukemia M2, were characterized through antibiotic susceptibility profiling, the detection of genes encoding carbapenem hydrolyzing oxacillinases, pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), adherence and invasion assays toward the A549 cell line, and the whole-genome sequence (WGS). The five strains showed Multidrug resistant (MDR) profiles and amplification of the blaOXA-23 gene, belonging to ST758 and grouped into two PFGE clusters. WGS of 810CP revealed the presence of a circular chromosome and two small plasmids, pAba810CPa and pAba810CPb. Both plasmids carried genes encoding the Sp1TA system, although resistance genes were not identified. A gene-by-gene comparison analysis was performed among the A. baumannii strains isolated in this study and others A. baumannii ST758 strains (HIMFG and INCan), showing that 86% of genes were present in all analyzed strains. Interestingly, the 433H, 434H, and 483H strains varied by 8–10 single-nucleotide variants (SNVs), while the A2 and 810CP strains varied by 46 SNVs. Subsequently, an analysis using BacWGSTdb showed that all of our strains had the same resistance genes and were ST758. However, some variations were observed in relation to virulence genes, mainly in the 810CP strain. The genes involved in the synthesis of hepta-acylated lipooligosaccharides, the pgaABCD locus encoding poly-β-1-6-N-acetylglucosamine, the ompA gene, Csu pili, bap, the two-component system bfms/bfmR, a member of the phospholipase D family, and two iron-uptake systems were identified in our A. baumannii strains genome. The five A. baumannii strains isolated from the child were genetically different and showed important characteristics that promote survival in a hospital environment. The elucidation of their genomic sequences provides important information for understanding their epidemiology, antibiotic resistance, and putative virulence factors

Treatment with tocilizumab or corticosteroids for COVID-19 patients with hyperinflammatory state: a multicentre cohort study (SAM-COVID-19)

Objectives: The objective of this study was to estimate the association between tocilizumab or corticosteroids and the risk of intubation or death in patients with coronavirus disease 19 (COVID-19) with a hyperinflammatory state according to clinical and laboratory parameters. Methods: A cohort study was performed in 60 Spanish hospitals including 778 patients with COVID-19 and clinical and laboratory data indicative of a hyperinflammatory state. Treatment was mainly with tocilizumab, an intermediate-high dose of corticosteroids (IHDC), a pulse dose of corticosteroids (PDC), combination therapy, or no treatment. Primary outcome was intubation or death; follow-up was 21 days. Propensity score-adjusted estimations using Cox regression (logistic regression if needed) were calculated. Propensity scores were used as confounders, matching variables and for the inverse probability of treatment weights (IPTWs). Results: In all, 88, 117, 78 and 151 patients treated with tocilizumab, IHDC, PDC, and combination therapy, respectively, were compared with 344 untreated patients. The primary endpoint occurred in 10 (11.4%), 27 (23.1%), 12 (15.4%), 40 (25.6%) and 69 (21.1%), respectively. The IPTW-based hazard ratios (odds ratio for combination therapy) for the primary endpoint were 0.32 (95%CI 0.22-0.47; p < 0.001) for tocilizumab, 0.82 (0.71-1.30; p 0.82) for IHDC, 0.61 (0.43-0.86; p 0.006) for PDC, and 1.17 (0.86-1.58; p 0.30) for combination therapy. Other applications of the propensity score provided similar results, but were not significant for PDC. Tocilizumab was also associated with lower hazard of death alone in IPTW analysis (0.07; 0.02-0.17; p < 0.001). Conclusions: Tocilizumab might be useful in COVID-19 patients with a hyperinflammatory state and should be prioritized for randomized trials in this situatio

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Modelado matemático de una estructura reflectiva para incrementar la irradiancia sobre paneles solares

En el presente proyecto se realiza el modelado matemático de una estructura reflectiva propuesta por los autores para incrementar la irradiancia sobre paneles solares, de tal manera que se obtenga un factor de incremento y posteriormente, pueda ser utilizado para analizar el comportamiento del panel en cuanto a sus condiciones estándares como: eficiencia, potencia y temperatura. La estructura reflectiva propuesta consta de espejos cuyas magnitudes tanto de orientación como de dimensiones se determinarán a través del modelamiento matemático del mismo. Durante el proceso de modelamiento, se ha considerado factores de gran importancia como el comportamiento de los distintos tipos de concentradores solares existentes en la actualidad, con la finalidad de analizar el efecto reflectivo de los mismos y aplicarlo.In the present project the mathematical modeling of a reflective structure proposed by the authors is done to increase the irradiance on solar panels, in such a way that an increase factor is obtained and later, it can be used to analyze the behavior of the panel in terms of its standard conditions such as: efficiency, power and temperature. The proposed reflective structure consists of mirrors whose magnitudes of both orientation and dimensions will be determined through mathematical modeling thereof. During the modeling process, factors of great importance have been considered, such as the behavior of the different types of solar concentrators currently in existence, in order to analyze the reflective effect of the same and apply it

Analytical recommendations for SARS-CoV-2 identification by RT-PCR in pediatric patients

Coronavirus disease 2019 (COVID-19) is caused by the severe acute respiratory syndrome 2 coronavirus (SARS-CoV-2) and is currently listed as a global public health emergency. Timely identification and protocol implementations for molecular detection of this virus are vital for medical decision-making. Identification of SARS-CoV-2 infection cases is based on detection of the virus RNA by molecular tests, particularly real-time reverse transcription-polymerase chain reaction (RT-PCR). Technical and operational details specific to each center must be considered to perform the molecular diagnosis of SARS-CoV-2 in pediatric patients. The term “qualified laboratories” involves laboratories in which all users, analysts, and anyone reporting results are trained to develop and interpret results through a procedure implemented previously by an instructor. Such knowledge is essential in detecting and identifying errors during each of its phases: pre-analytical, analytical, and post-analytical, which allow the establishment of continuous improvement policies to ensure the quality of the results, but above all, the physical integrity of health workers