LibGen: Generating High Quality Spectral Libraries of Natural Products for EAD-, UVPD-, and HCD-High Resolution Mass Spectrometers.

Compound annotation using spectral-matching algorithms is vital for (MS/MS)-based metabolomics research, but is hindered by the lack of high-quality reference MS/MS library spectra. Finding and removing errors from libraries, including noise ions, is mostly done manually. This process is both error-prone and time-consuming. To address these challenges, we have developed an automated library curation pipeline, LibGen, to universally build novel spectral libraries. This pipeline corrects mass errors, denoises spectra by subformula assignments, and performs quality control of the reference spectra by calculating explained intensity and spectral entropy. We employed LibGen to generate three high-quality libraries with chemical standards of 2241 natural products. To this end, we used an IQ-X orbital ion trap mass spectrometer to generate 1947 classic high-energy collision dissociation spectra (HCD) as well as 1093 ultraviolet-photodissociation (UVPD) mass spectra. The third library was generated by an electron-activated collision dissociation (EAD) 7600 ZenoTOF mass spectrometer yielding 3244 MS/MS spectra. The natural compounds covered 140 chemical classes from prenol lipids to benzypyrans with >97% of the compounds showing <0.2 Tanimoto-similarity, demonstrating a very high structural variance. Mass spectra showed much higher information content for both UVPD- and EAD-mass spectra compared to classic HCD spectra when using spectral entropy calculations. We validated the denoising algorithm by acquiring MS/MS spectra at high concentration and at 13-fold diluted chemical standards. At low concentrations, a higher proportion of spectra showed apparent fragment ions that could not be explained by subformula losses of the parent molecule. When more than 10% of the total intensity of MS/MS fragments was regarded as noise ions, spectra were considered as low quality and were not included in the libraries. As the overall process is fully automated, LibGen can be utilized by all researchers who create or curate mass spectral libraries. The libraries we created here are publicly available at MassBank.us.

Awakening the natural capability of psicose production in Escherichia coli.

Due to the rampant rise in obesity and diabetes, consumers are desperately seeking for ways to reduce their sugar intake, but to date there are no options that are both accessible and without sacrifice of palatability. One of the most promising new ingredients in the food system as a non-nutritive sugar substitute with near perfect palatability is D-psicose. D-psicose is currently produced using an in vitro enzymatic isomerization of D-fructose, resulting in low yield and purity, and therefore requiring substantial downstream processing to obtain a high purity product. This has made adoption of D-psicose into products limited and results in significantly higher per unit costs, reducing accessibility to those most in need. Here, we found that Escherichia coli natively possesses a thermodynamically favorable pathway to produce D-psicose from D-glucose through a series of phosphorylation-epimerization-dephosphorylation steps. To increase carbon flux towards D-psicose production, we introduced a series of genetic modifications to pathway enzymes, central carbon metabolism, and competing metabolic pathways. In an attempt to maximize both cellular viability and D-psicose production, we implemented methods for the dynamic regulation of key genes including clustered regularly interspaced short palindromic repeats inhibition (CRISPRi) and stationary-phase promoters. The engineered strains achieved complete consumption of D-glucose and production of D-psicose, at a titer of 15.3 g L-1, productivity of 2 g L-1 h-1, and yield of 62% under test tube conditions. These results demonstrate the viability of whole-cell catalysis as a sustainable alternative to in vitro enzymatic synthesis for the accessible production of D-psicose.

Validez y confiablidad de una escala para medir depresión, ansiedad y estrés aplicada a estudiantes de estomatología cubanos durante la COVID-19 / Validity and reliability of a depression, anxiety and stress scale in Cuban dental students during the COVID-19

Introduction: An indisputable consequence has to do with the psychological impact of the COVID-19 on health professionals and students. In Cuba, these psychological manifestations have scarcely been investigated, and there are no reports in the dental undergraduate program. Objective: To analyze the evidences of validity and reliability of a depression, anxiety and stress scale in Cuban dental students in the context of COVID-19. Methods: An instrumental and cross-sectional study was carried out, which included students of all years and Cuban universities. A documentary measurement instrument was validated, using its main psychometric evidence. Convergent validity was analyzed and reliability was estimated using Cronbach's alpha coefficient. Results: 301 students were included, of which 74.09 percent were women and whose ages ranged from 17 to 30 years. The asymmetry and kurtosis values of all items were adequate. The confirmatory factorial analysis showed that the factorial structure of 21 items distributed in 3 factors is satisfactory. The goodness of fit indices was equally satisfactory. The scale factors are directly and significantly related with the Generalized Anxiety Disorder-2 (p<0.01) and the Patient Health Questionnaire-2 (p<0.01); the scale shows evidences of convergent validity. With Cronbach's α coefficient, the scale scores were estimated to be reliable. Conclusions: The depression, anxiety and stress scale (DASS-21) in Cuban dental students in the context of COVID-19 turned out to be valid and reliable, in addition to allowing the evaluation of the dimensions of these three factors in this sector of the society(AU)

Introducción: La COVID-19 produce un innegable impacto psicológico en estudiantes y profesionales de la salud. En Cuba, estas manifestaciones psicológicas apenas se han estudiado, y no existen informes al respecto en el programa de pregrado que corresponde a estomatología. Objetivo: Analizar las evidencias sobre validez y confiablidad de una escala para medir depresión, ansiedad y estrés en estudiantes de estomatología cubanos en el contexto de la COVID-19. Métodos: Se realizó un estudio instrumental y trasversal con estudiantes de todos los cursos y universidades cubanas. Se validó un instrumento de medición de tipo documental mediante su principal evidencia psicométrica. Se analizó la validez convergente y se estimó la confiabilidad mediante el coeficiente alfa de Cronbach. Resultados: Se incluyeron 301 estudiantes, el 74,09 por ciento de los cuales son mujeres y cuyas edades oscilan de diecisiete a treinta años. Los valores de la asimetría y la curtosis de todos los ítems fueron adecuados. El análisis factorial confirmatorio mostró que la estructura factorial de los 21 ítems distribuidos en tres factores es satisfactoria. La bondad de los índices de ajuste también fue satisfactoria. Los factores de la escala están directa y significativamente relacionados con la escala para medir el trastorno de ansiedad gefneralizas-2 (p<0,01) y con el cuestionario sobre salud del paciente-2. La escala muestra evidencias de validez convergente. El coeficiente alfa de Cronbach permitió estimar la confiablidad de las puntuaciones del instrumento. Conclusiones: La escala para medir depresión, ansiedad y estrés (DASS-21) aplicada a estudiantes de estomatología cubanos en el contexto de la COVID-19 resulto ser válida y confiable, además de permitir la evaluación de las dimensiones de estos tres factores en este sector de la sociedad(AU)

Alternative Identification of Glycosides Using MS/MS Matching with an In Silico-Modified Aglycone Mass Spectra Library.

Glycosylation of metabolites serves multiple purposes. Adding sugars makes metabolites more water soluble and improves their biodistribution, stability, and detoxification. In plants, the increase in melting points enables storing otherwise volatile compounds that are released by hydrolysis when needed. Classically, glycosylated metabolites were identified by mass spectrometry (MS/MS) using [M-sugar] neutral losses. Herein, we studied 71 pairs of glycosides with their respective aglycones, including hexose, pentose, and glucuronide moieties. Using liquid chromatography (LC) coupled to electrospray ionization high-resolution mass spectrometry, we detected the classic [M-sugar] product ions for only 68% of glycosides. Instead, we found that most aglycone MS/MS product ions were conserved in the MS/MS spectra of their corresponding glycosides, even when no [M-sugar] neutral losses were observed. We added pentose and hexose units to the precursor masses of an MS/MS library of 3057 aglycones to enable rapid identification of glycosylated natural products with standard MS/MS search algorithms. When searching unknown compounds in untargeted LC-MS/MS metabolomics data of chocolate and tea, we structurally annotated 108 novel glycosides in standard MS-DIAL data processing. We uploaded this new in silico-glycosylated product MS/MS library to GitHub to enable users to detect natural product glycosides without authentic chemical standards.

Effects of lockdown by COVID-19 on glycemic control of Cuban children and adolescents with type 1 diabetes mellitus / Efectos del confinamiento por COVID-19 sobre el control glucémico de niños y adolescentes con diabetes mellitus tipo 1 / Efeitos do confinamento COVID-19 no controle glicêmico de crianças e adolescentes com diabetes mellitus tipo 1

Introduction: The purpose of this study was to determine the impact of confinement due to COVID-19 on glycemic control in children and adolescents with type 1 diabetes mellitus. Material and methods: An observational, descriptive study with a prospective design was carried out in Cuba, between November 2020 and May 2021. The sample consisted of 41 children and adolescents from a Provincial Center for Care and Education for Diabetic Patients. Anthropometric measurements (weight, height, and BMI) were obtained from the patients' medical records at the time of debut and at the time of the follow-up visit during the study period. Glycemic control was determined from the value of glycosylated hemoglobin (HbA1c). The comparison of the means between independent groups of variables was carried out using the ANOVA analysis of variance of a Kruskal-Wallis factor when quantitative variables were brought, and Pearson's Chi square in the case of categorical variables. Results: It was shown that during confinement, 78.05% of the patients had poor glycemic control. In addition, the requirements for higher total doses of insulin (p=0.005), both fast-acting (p=0.011) and slow-acting (p=0.008), and the highest dosage by weight in kilograms (p=0.003), and the highest evolution time (p=0.011) were significantly related to poor glycemic control. Most of the variables that were associated with poor glycemic control during confinement were also associated before said period. Conclusions: The confinement had a negative impact on the glycemic control of children and adolescents with type 1 diabetes mellitus in Cuba, since during this period the patients required higher doses of insulin and showed higher HbA1c figures.

Introducción: El propósito de este estudio fue determinar el impacto del confinamiento por COVID-19 en el control glucémico de niños y adolescentes con diabetes mellitus tipo 1. Material y métodos: Se realizó un estudio observacional, descriptivo con diseño prospectivo en Cuba, entre noviembre de 2020 y mayo de 2021. La muestra estuvo constituida por 41 niños y adolescentes de un Centro Provincial de Atención y Educación al Paciente Diabético. Las mediciones antropométricas (peso, talla e IMC) fueron obtenidas de las historias clínicas de los pacientes al momento del debut y al momento de la consulta de seguimiento durante el periodo del estudio. El control glucémico fue determinado a partir del valor de la hemoglobina glucosilada (HbA1c). La comparación de las medias entre grupos de variables independientes fue llevada a cabo mediante el análisis de varianza ANOVA de un factor de Kruskal-Wallis cuando se trataba de variables cuantitativas, y Chi cuadrado de Pearson en el caso de las variables categóricas. Resultados: Se observó que durante el confinamiento el 78,05 % de los pacientes presentaban un mal control glucémico. Además, los requerimientos de mayores dosis totales de insulina (p=0,005), tanto de acción rápida (p=0,011) como lenta (p=0,008), y la mayor dosificación por peso en kilogramos (p=0,003), y el mayor tiempo de evolución (p=0,011) se relacionaron significativamente con el mal control glucémico. La mayoría las variables que se asociaron a un mal control glucémico durante el confinamiento, también lo hacían antes de dicho período. Conclusiones: El confinamiento tuvo un impacto negativo sobre el control glucémico de niños y adolescentes con diabetes mellitus tipo 1 en Cuba, ya que durante este período los pacientes requirieron mayores dosis de insulina y mostraron mayores cifras de HbA1c.

Introdução: O objetivo deste estudo foi determinar o impacto do confinamento devido ao COVID-19 no controle glicêmico em crianças e adolescentes com diabetes mellitus tipo 1. Material e métodos: Estudo observacional, descritivo, com desenho prospectivo, realizado em Cuba, entre novembro de 2020 e maio de 2021. A amostra foi composta por 41 crianças e adolescentes de um Centro Provincial de Atenção e Educação para Diabéticos. As medidas antropométricas (peso, altura e IMC) foram obtidas dos prontuários dos pacientes no momento da estreia e no momento da consulta de acompanhamento durante o período do estudo. O controle glicêmico foi determinado a partir do valor da hemoglobina glicosilada (HbA1c). A comparação das médias entre grupos de variáveis ​​independentes foi realizada por meio da análise de variância ANOVA de um fator de Kruskal-Wallis no caso de variáveis ​​quantitativas e do Qui-quadrado de Pearson no caso de variáveis ​​categóricas. Resultados: Observou-se que durante o confinamento, 78,05% dos pacientes apresentaram mau controle glicêmico. Além disso, as necessidades de maiores doses totais de insulina (p=0,005), tanto de ação rápida (p=0,011) quanto de ação lenta (p=0,008), e a maior dosagem por peso em quilogramas (p=0,003), e o maior tempo de evolução (p=0,011) relacionaram-se significativamente com o mau controle glicêmico. A maioria das variáveis ​​que se associaram ao mau controle glicêmico durante o confinamento também se associaram antes desse período. Conclusões: O confinamento teve um impacto negativo no controle glicêmico de crianças e adolescentes com diabetes mellitus tipo 1 em Cuba, pois durante esse período os pacientes necessitaram de doses mais altas de insulina e apresentaram valores de HbA1c mais elevados.

[Validity and Reliability of the Wong-Law Emotional Intelligence Scale (WLEIS) in Cuban Dental Students in COVID-19 Times]. / Validez y confiabilidad de la Wong-Law Emotional Intelligence Scale (WLEIS) en estudiantes cubanos de Estomatología en tiempos de COVID-19.

Introduction: The pandemic produced by SARS-CoV-2 impacted on educative systems, which justifies the necessity of research about the emotional capacities of the university students to face the challenges that COVID-19 imposes. Objective: To analyze the evidences of validity and reliability of the Wong-Law Emotional Intelligence Scale (WLEIS) in Cuban dental students. Materials and methods: Cross-sectional study with instrumental design. The scale was administered through a virtual questionnaire and later distributed by means of social networks to 307 students (81 male and 226 female). A confirmatory factorial analysis was performed and the intern consistency and the relation between the scale and other variables were evaluated. Results: Through the confirmatory factorial analysis, the model of four correlationated factors was evaluated and an adequate adjust was found, χ2(98) = 303.1, P < .001, CFI = 0.948, TLI = 0.937, RMSEA = 0.083 and SRMR = 0.064. The results of the Omega intern consistency are ωSEA = 0.84, ωOEA = 0.77, ωUOE = 0.83 and ωUROE = 0.91. With respect to the relation of WLEIS with other variables, we had correlations ranging from 0.22 and 0.51 with general well-being, and inverse correlations ranging from -1 and -0.29 of three of its dimensions with depression, showing evidences of convergent and discriminant validity. Conclusion: The WLEIS in Cuban dental students in COVID-19 times resulted be valid and reliable.

Validation and application of the Insulin Treatment Appraisal Scale in Cuban patients with type 2 diabetes mellitus.

INTRODUCTION: The purpose of this study was to validate the Insulin Treatment Appraisal Scale (ITAS) in the Cuban population with type 2 diabetes mellitus. MATERIAL AND METHODS: A cross-sectional, multicentre analytical study was performed in Cuba from February 2020 to April 2021; 199 patients were surveyed in a hospital institution and in primary healthcare. We used the Insulin Treatment Appraisal Scale, consisting of 20 items, with a minimum score of 20 points and a maximum of 100, where the higher the score, the worse the perception of insulin therapy. The validity of the instrument was determined by means of an exploratory factor analysis. The internal consistency and reliability of the scale were calculated by means of Cronbach's alpha coefficient. A K-means cluster analysis was performed to establish a cut-off point for poor perception of insulin therapy. RESULTS: The exploratory factor analysis supported the validity of the instrument, with a Cronbach's alpha of 0.747. There were statistically significant differences between patients under insulin and non-insulin treatment in terms of the answers given in all items of the scale. The total mean score obtained was 51.96 ±â€¯10.78, and it was lower in insulin users compared to those who used other drugs (49.79 ±â€¯10.07 vs 55.09 ±â€¯11.12). A score ≥65 was proposed as a cut-off point for poor perception of insulin therapy. A positive relationship was found between the body mass index values and the total score of the scale. Being female and current treatment not involving insulin were factors associated with low perception of insulin therapy. CONCLUSIONS: The instrument proved to be valid for the population in which it was applied. Insulin users turned out to be the ones with the best perception about its use. A cut-off point of ≥65 points for poor perception of insulin treatment was proposed for evaluation and comparison in future studies in other patient populations.

Lesion Length as a Prognosis Marker of Mortality in Patients with Fournier's Gangrene: Proposal of a New Scoring System.

OBJECTIVE: To assess the prognostic value of mortality of a new system for quantifying the lesion length circumscribed to the genitals and adjacent anatomical areas in patients with Fournier's gangrene. METHODS: An observational, analytical and prospective study in the Urology service of the Arnaldo Milián Castro University Hospital, between January 2007 and December 2019. The sample consisted of 60 patients diagnosed with Fournier's gangrene. To determine the lesion length, a new quantification system was designed by the authors. Its predictive capacity was determined by binary logistic regression analysis and its discriminatory capacity by the area under the ROC curve. RESULTS: In the studied sample, Fournier's gangrene mortality was 26.7%. The logistic regression analysis demonstrated the prognostic value of mortality of the quantification system evaluated, for each point that the extension of the lesion increased, the risk of death increased by approximately five times, thus being superior to the methods previously used to quantify the injury. Results of the calibration of the quantification system by the Hosmer-Lemeshhow test showed that the data were adjusted to the regression equation (p = 0.278). An area under the curve of 0.957 was observed, which reflects a good discriminatory capacity, showing a sensitivity of 93.75% and a specificity of 93.18%. CONCLUSIONS: The system for quantifying the lesion length in patients with Fournier's gangrene proposed in the present study showed an excellent prognostic value for mortality. The integration of this new method into others prognostic scores could substantially increase sensibility and specificity on diagnostic, by means of offering a more precise approach of the lesion dimensions.

Lesion Length as a Prognosis Marker of Mortality in Patients with Fournier’s Gangrene: Proposal of a New Scoring System

Objective: To assess the prognostic value of mortality of a new system for quantifying the lesion length circumscribed to the genitals and adjacent anatomical areas in patients with Fournier’s gangrene. Methods: An observational, analytical and prospective study in the Urology service of the Arnaldo Milián Castro University Hospital, between January 2007 and December 2019. The sample consisted of 60 patients diagnosed with Fournier’s gangrene. To determine the lesion length, a new quantification system was designed by the authors. Its predictive capacity was determined by binary logistic regression analysis and its discriminatory capacity by the area under the ROC curve. Results: In the studied sample, Fournier’s gangrene mortality was 26.7%. The logistic regression analysis demonstrated the prognostic value of mortality of the quantification system evaluated, for each point that the extension of the lesion increased, the risk of death increased by approximately five times, thus being superior to the methods previously used to quantify the injury. Results of the calibration of the quantification system by the Hosmer-Lemeshhow test showed that the data were adjusted to the regression equation (p = 0.278). An area under the curve of 0.957 was observed, which reflects a good discriminatory capacity, showing a sensitivity of 93.75% and a specificity of 93.18%. Conclusions: The system for quantifying the lesion length in patients with Fournier’s gangrene proposed in the present study showed an excellent prognostic value for mortality. The integration of this new method into others prognostic scores could substantially increase sensibility and specificity on diagnostic, by means of offering a more precise approach of the lesion dimensions (AU)

Temporal inequality of RR intervals like a new psychophysiological indicator of mental stress / Desigualdad temporal de los intervalos RR como nuevo indicador psicofisiológico de estrés mental / Desigualdade temporal de intervalos RR como um novo indicador psicofisiológico de estresse mental

Introduction: Gini coefficient (Gini index or Gini ratio) is a parameter that is normally used in economy to measure the income distribution in a country or in the whole wide world, but it can be used to measure any kind of distribution. In the present study it is exposed an innovative proposal of application of the Gini coefficient to Heart Rate Variability (HRV) like a psychophysiological indicator of mental stress. Purpose: To assess the application of the Gini coefficient as a psychophysiological indicator of mental stress. Methods: The involved participants are 13 healthy individuals (age 19 ± 1.5 years). Heart rate was continuously recorded at rest (5 minutes) and during a mental stress (5 minutes). Linear and nonlinear methods of heart rate variability were assessed, and 2 new indicators (Sequential and Non-Sequential Gini) were calculated and proposed to measure HRV differences between states. Results: When comparing rest and mental stress conditions, a sensible decrease of the traditional indicators of the HRV was founded (p<0.05), an increase of the heart rate (p=0.004) and of the Sequential Gini (p=0.004) and Non-Sequential Gini (p=0.04). Conclusions: The results suggest that temporary inequality of the RR intervals analyzed from the Gini coefficient could be an adequate indicator of sympathetic activity present during the mental stress, with great potentialities with the objective to assess the consequences of psychosomatic affections and anxiety disorders.

Introducción: El coeficiente de Gini o índice de Gini es un parámetro que normalmente se usa en economía para medir la distribución del ingreso en un país o en todo el mundo, pero puede usarse para medir cualquier tipo de distribución. En el presente estudio se expone una propuesta innovadora de aplicación del coeficiente de Gini a la Variabilidad de la Frecuencia Cardíaca (VFC) como indicador psicofisiológico del estrés mental. Objetivo: Evaluar la aplicación del coeficiente de Gini como indicador psicofisiológico de estrés mental. Métodos: Los participantes involucrados son 13 individuos sanos (edad 19 ± 1,5 años). La frecuencia cardíaca se registró continuamente en reposo (5 minutos) y durante un estrés mental (5 minutos). Se evaluaron métodos lineales y no lineales de variabilidad de la frecuencia cardíaca, y se calcularon y propusieron 2 nuevos indicadores (Gini secuencial y no secuencial) para medir las diferencias de VFC entre estados. Resultados: Al comparar las condiciones de reposo y estrés mental, se encontró una sensible disminución de los indicadores tradicionales de la VFC (p<0,05), un aumento de la frecuencia cardiaca (p=0,004) y del Gini Secuencial (p=0,004) y Gini no secuencial (p=0,04). Conclusiones: Los resultados sugieren que la desigualdad temporal de los intervalos RR analizados a partir del coeficiente de Gini podría ser un indicador adecuado de la actividad simpática presente durante el estrés mental, con grandes potencialidades en la evaluación las consecuencias de afecciones psicosomáticas y trastornos de ansiedad.

Introdução: O coeficiente de Gini ou índice de Gini é um parâmetro normalmente usado em economia para medir a distribuição de renda em um país ou no mundo, mas pode ser usado para medir qualquer tipo de distribuição. No presente estudo, apresenta-se uma proposta inovadora de aplicação do coeficiente de Gini à Variabilidade da Frequência Cardíaca (VFC) como indicador psicofisiológico de estresse mental.Objetivo: Avaliar a aplicação do coeficiente de Gini como indicador psicofisiológico de estresse mental.Métodos: Os participantes envolvidos são 13 indivíduos saudáveis ​​(idade 19 ± 1,5 anos). A frequência cardíaca foi registrada continuamente em repouso (5 minutos) e durante o estresse mental (5 minutos). Métodos lineares e não lineares de variabilidade da frequência cardíaca foram avaliados e 2 novos indicadores (gini sequencial e não sequencial) foram calculados e propostos para medir as diferenças na VFC entre os estados.Resultados: Ao comparar as condições de repouso e estresse mental, foi encontrada diminuição significativa nos indicadores tradicionais da VFC (p<0,05), aumento da frequência cardíaca (p=0,004) e do Gini Sequencial (p= 0,004) e não - Gini sequencial (p=0,04).Conclusões: Os resultados sugerem que a desigualdade temporal dos intervalos RR analisados ​​a partir do coeficiente de Gini pode ser um indicador adequado da atividade simpática presente durante o estresse mental, com grande potencial na avaliação das consequências de condições psicossomáticas e transtornos de ansiedade.

Cambios de autoría al publicar los trabajos presentados en fórums nacionales estudiantiles

RESUMEN Introducción: Los problemas con la autoría de los artículos son frecuentes; sin embargo, en Cuba existen pocas investigaciones sobre el tema. Objetivo: Determinar los cambios de autoría en la publicación de los trabajos presentados en fórums nacionales estudiantiles de ciencias médicas en Cuba y sus factores asociados. Métodos: Estudio observacional y transversal con empleo de técnicas analíticas, que incluyó a la totalidad de los trabajos presentados en las ediciones 2016, 2017 y 2019 del Fórum Nacional de Ciencias Médicas. Mediante una estrategia de búsqueda en Google Académico se constató si los trabajos habían sido publicados en revistas científicas. Luego se identificaron los cambios en la autoría y se buscaron factores asociados. Se obtuvieron razones de prevalencia (RPa), intervalos de confianza al 95 % y valores p mediante modelos lineales generalizados. Resultados: De los 129 trabajos publicados, el 89,9 % (n= 116) tuvo cambios de autoría. En el análisis multivariado, hubo más frecuencia de cambios en los autores cuando los artículos se publicaron en revistas de profesionales (RPa: 1,29; IC 95 %: 1,11-1,50; p= 0,001) y cuando la publicación se dio posterior al evento (RPa: 1,20; IC 95 %: 1,01-1,42; p= 0,042); lo cual fue contrario cuando el autor para la correspondencia fue estudiante (RPa: 0,79; IC 95 %: 0,66-0,95; p= 0,010), ajustado por tres variables. Conclusiones: Casi la totalidad de los artículos tiene cambios en los autores y existen algunos factores asociados a una mayor o menor frecuencia en esos cambios (publicación, tiempo y autor corresponsal).

ABSTRACT Introduction: The problems with the articles' authorship are frequent; however, in Cuba there are few investigations on the topic. Objective: To determine the authorship changes in the publication of works presented in medical student forums at national level in Cuba and its associated factors. Methods: Observational and cross-sectional study using analytical techniques, that included all the works presented in 2016, 2017 and 2019 editions of the medical student forums at national level. A Google Scholar search strategy was carried out in order to check if these works had been published in scientific journals. After, authorship changes were identified and associated factors were looked for. Prevalence ratios (aPR), 95 % confidence intervals (95 % CI) and p values using generalized linear models were obtained. Results: Of the 129 published works, 89,9 % (n= 116) had authorship changes. In the multivariate analysis, there was more frequency of authorship changes when the articles were published in professionals' journals (aPR: 1,29; IC 95 %: 1,11 - 1,50; p= 0,001) and when the publication occurred later to the event (aPR: 1,20; IC 95 %: 1,01 - 1,42; p= 0,042); that which was contrary when the corresponding author was a student (aPR: 0,79; IC 95 %: 0,66 - 0,95; p= 0,010), adjusted by three variables. Conclusion: Almost the entirety of the articles had authorship changes and some factors associated to a higher or smaller frequency in those changes were determined (publication, time and corresponding author).

Perceived Stress by Students of the Medical Sciences in Cuba Toward the COVID-19 Pandemic: Results of an Online Survey.

INTRODUCTION: The aims of this study were to determine the usefulness of the Modified (10-item) Scale of Perceived Stress related to COVID-19 (EEP-10-C, for its acronym in Spanish) and to identify the levels of stress perceived by students of medical sciences in Cuba due to the COVID-19 pandemic. METHODS: A cross-sectional study was conducted, with self-reported data of students from 14 Cuban universities of medical sciences (n=200), through an online survey. The EEP-10-C was used as an instrument to identify stress. Its validity was determined through a confirmatory factor analysis and its internal consistency and reliability was measured by the Cronbach's alpha. A cluster analysis was performed to establish as the cut-off point the centre of the cluster with the highest values of stress perceived by the scale. RESULTS: The average age of the sample was 23.30± 1.91 years, with observed scores of the EEP-10-C between 0 and 29 points (13.25±5.404). When applying the cut-off point ≥25, only two students had high rates of perceived stress. The confirmatory factor analysis supported the validity of the instrument (α=0.755). The cut-off point ≥20 was proposed as a reference of high stress perceived for the study population, when applying this one, 14% of students presented high rates of stress. CONCLUSIONS: In Cuba, students of the medical sciences have participated in research and healthcare support, despite which they have presented low levels of stress. The main contribution of the research was the validation of the EEP-10-C for its use in assessing levels of stress in Cuban medical students, proposing the cut-off point ≥20 as a reference of high stress perceived.

Perceived Stress by Students of the Medical Sciences in Cuba Toward the COVID-19 Pandemic: Results of an Online Survey / Estrés percibido por estudiantes de ciencias médicas en Cuba ante la pandemia por COVID-19: resultados de una encuesta en línea

ABSTRACT Introduction: The aims of this study were to determine the usefulness of the Modified (10-item) Scale of Perceived Stress related to COVID-19 (EEP-10-C, for its acronym in Spanish) and to identify the levels of stress perceived by students of medical sciences in Cuba due to the COVID-19 pandemic. Methods: A cross-sectional study was conducted, with self-reported data of students from 14 Cuban universities of medical sciences (n = 200), through an online survey. The EEP-10-C was used as an instrument to identify stress. Its validity was determined through a confirmatory factor analysis and its internal consistency and reliability was measured by the Cronbach's alpha. A cluster analysis was performed to establish as the cut-off point the centre of the cluster with the highest values of stress perceived by the scale. Results: The average age of the sample was 23.30 ± 1.91 years, with observed scores of the EEP-10-C between 0 and 29 points (13.25 ± 5.404). When applying the cut-off point >25, only two students had high rates of perceived stress. The confirmatory factor analysis supported the validity of the instrument (a = 0.755). The cut-off point >20 was proposed as a reference of high stress perceived for the study population, when applying this one, 14% of students presented high rates of stress. Conclusions: In Cuba, students of the medical sciences have participated in research and healthcare support, despite which they have presented low levels of stress. The main contribution of the research was the validation of the EEP-10-C for its use in assessing levels of stress in Cuban medical students, proposing the cut-off point >20 as a reference of high stress perceived.

RESUMEN Introducción: Los objetivos de este estudio fueron determinar la utilidad de la Escala de Estrés Percibido Modificada (10 ítems) relacionada con COVID-19 (EEP-10-C) e identificar los niveles de estrés percibido por estudiantes de ciencias médicas en Cuba por la pandemia de COVID-19. Métodos: Se realizó un estudio transversal, con datos informados por los estudiantes de 14 universidades de ciencias médicas de Cuba (n = 200) a través de una encuesta en línea. El EEP-10-C se utilizó como instrumento para identificar el estrés. Su validez se determinó mediante análisis factorial confirmatorio y su consistencia interna y su confiabilidad, mediante alfa de Cronbach. Se realizó un análisis de conglomerados para establecer como punto de corte el centro del conglomerado con los valores más altos de estrés percibido en la escala. Resultados: La edad promedio de la muestra fue 23,30 ± 1,91 anos, con puntajes observados de la EEP-10-C entre0y29 puntos (13,25 ± 5,404). Al aplicar el punto de corte > 25, solo 2 estudiantes tuvieron altos índices de estrés percibido. El análisis factorial confirmatorio respaldó la validez del instrumento (a = 0,755). Se propuso el punto de corte > 20 como referencia de alto estrés percibido para la población de estudio; al aplicarlo, el 14% de los estudiantes tenían altos índices de estrés. Conclusiones: En Cuba, estudiantes de ciencias médicas han participado en investigaciones y apoyo a la atención de la salud, a pesar de lo cual han presentado bajos niveles de estrés. El principal aporte de la investigación fue la validación de la EEP-10-C para su uso en la evaluación de los niveles de estrés de los estudiantes de Medicina cubanos, y se propone el punto de corte > 20 como referencia del alto estrés percibido.

Factores pronósticos de mortalidad en pacientes con melanoma maligno cutáneo / Mortality Prognostic Factors in Patients with Cutaneous Malignant Melanoma

RESUMEN Fundamento: el melanoma maligno cutáneo es el tumor de piel más letal, por lo que resulta importante conocer los factores de riesgo de mortalidad de los pacientes que lo padecen. Objetivo: determinar los factores pronósticos de mortalidad en pacientes con melanoma maligno cutáneo diagnosticados y tratados en el Hospital Universitario Docente Celestino Hernández Robau entre enero de 2010 a diciembre de 2015. Método: se realizó un estudio observacional analítico de cohorte retrospectivo. La población estuvo constituida por todos los pacientes con melanoma maligno cutáneo diagnosticados y tratados en el Hospital en el periodo de estudio (N=142), y la muestra por 112 pacientes. Las variables analizadas fueron: edad, sexo, color de piel, subtipo histológico, índice de Breslow, nivel de Clark, índice mitótico, afectación ganglionar, metástasis a distancia, ulceración, localización topográfica, estadio clínico, tipo de tratamiento y niveles de lactato-deshidrogenasa sanguínea al diagnóstico. Se determinó el Odds Ratio (OR) y sus intervalos de confianza (IC) para los factores estadísticamente significativos. Se evaluó el área bajo la curva ROC para las variables cuantitativas y se realizó un análisis multivariado mediante Regresión Logística Binaria. Se trabajó con una confiabilidad del 95 %. Resultados: el análisis multivariado identificó como factores pronósticos de mortalidad el índice de Breslow con un estadístico C de 0,849 (IC:0,770-0,923), el nivel de Clark V (OR:1,246;IC:0,985-1,870), índice mitótico ≥ 6mm2 (OR:12,408;IC:9,012-14,897), afectación ganglionar ≥ 2 ganglios (OR=6,316;IC=4,541-8,291), metástasis a pulmón u otras vísceras (OR:6,206;IC:4,342-8,001), localización del tumor en cabeza, cuello o tronco (OR:9,720;IC:7,684-12,546), ulceración (OR:0,528;IC:0,120-0,856), tratamiento no quirúrgico (OR:8,311;IC:7,098-9,366) y el valor de LDH en sangre≥333 UI/l (OR:18,905;IC:14,750-21,053). Conclusiones: los factores pronósticos de mortalidad en pacientes con diagnóstico de melanoma maligno cutáneo fueron: el índice de Breslow, el nivel de Clark, el índice mitótico, la afectación ganglionar, las metástasis a pulmón u otras vísceras, la localización del tumor en cabeza, cuello o tronco, la presencia de ulceración, el tratamiento no quirúrgico y los mayores valores de LDH en sangre.

ABSTRACT Background cutaneous malignant melanoma is the most lethal skin tumor, so it is important to know the risk factors for mortality in patients who suffer from it. Objective to determine the prognostic factors of mortality in patients with cutaneous malignant melanoma diagnosed and treated at the Celestino Hernández Robau Teaching University Hospital between January 2010 and December 2015. Method a retrospective cohort analytical observational study was carried out. The population consisted of all patients with cutaneous malignant melanoma diagnosed and treated at the Hospital in the study period (N = 142), and the sample was 112 patients. The variables analyzed were: age, sex, skin color, histological subtype, Breslow index, Clark level, mitotic index, lymph node involvement, distant metastasis, ulceration, topographic location, clinical stage, type of treatment, and lactate dehydrogenase levels blood at diagnosis. The Odds Ratio (OR) and its confidence intervals (CI) were determined for the statistically significant factors. The area under the ROC curve was evaluated for the quantitative variables and a multivariate analysis was performed using Binary Logistic Regression. It was a reliability of 95 %. Results the multivariate analysis identified as prognostic factors of mortality the Breslow index with a C statistic of 0.849 (CI: 0.770-0.923), the Clark V level (OR: 1.246; CI: 0.985-1.870), mitotic index ≥ 6mm2 (OR: 12.408; CI: 9.012-14.897), lymph node involvement ≥ 2 nodes (OR = 6.316; CI = 4.541-8.291), metastasis to lung or other viscera (OR: 6.206; CI: 4.342-8.001), tumor location on the head, neck or trunk (OR: 9.720; CI: 7.684-12.546), ulceration (OR: 0.528; CI: 0.120-0.856), non-surgical treatment (OR: 8.311; CI: 7.098-9.366) and the LDH value in blood ≥333 IU / l (OR: 18.905; CI: 14.750-21.053). Conclusions the prognostic factors of mortality in patients with a diagnosis of cutaneous malignant melanoma were the Breslow index, the Clark level, the mitotic index, lymph node involvement, metastases to the lung or other viscera, the location of the tumor in the head, neck or trunk, the presence of ulceration, non-surgical treatment and the highest values ​​of LDH in blood.

Becas internacionales de investigación en Cuba: espacios para la superación científica estudiantil / International research scholarships in Cuba: Spaces for students' scientific improvement

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Respuesta autonómica cardiovascular al estrés mental inducido por la prueba de cálculo aritmético / Autonomic cardiovascular response to mental stress induced by the arithmetic computation test

Introducción: El estrés mental agudo, así como los estados de ansiedad inducidos para influenciar la reactividad psicofisiológica en jóvenes sanos, aportan cambios en los patrones nerviosos que pueden ser medidos mediante la variabilidad de la frecuencia cardiaca. Objetivo: Determinar las diferencias en los parámetros lineales del balance autonómico cardiovascular en individuos jóvenes en estado basal y durante la prueba de cálculo aritmético. Métodos: Se realizó un estudio cuasi-experimental, sin grupo control de tipo antes y después, en el Laboratorio de Ciencias Básicas Biomédicas de la Universidad de Ciencias Médicas de Santiago de Cuba. Población y muestra de 10 sujetos. Se registró el trazado electrocardiográfico (5 min) durante el reposo y luego durante la prueba de cálculo aritmético. Resultados: Existieron diferencias significativas entre ambos estados en las variables frecuencia cardiaca (p = 0,005); mínima (p = 0,007); máxima (p = 0,005); intervalo RR (p = 0,005); stress index (p = 0,028); índice simpático (p = 0,005); bajas frecuencias (p = 0,005); relación LF/HF (p = 0,005); RMSSD (p = 0,007); NN50 (p = 0,008); pNN50 (p = 0,005); índice parasimpático (p = 0,005) y altas frecuencias (p = 0,005). El estrés mental provocó una disminución parasimpática y un predominio simpático uniforme en todos los sujetos participantes en el estudio. Conclusiones: Durante el estrés mental inducido por la prueba de cálculo aritmético la dinámica lineal de la respuesta autonómica cardiovascular experimenta un aumento en la actividad simpática y una disminución del tono parasimpático, traduciendo una respuesta adaptativa en la regulación de la función cardiovascular por el sistema nervioso autónomo(AU)

Introduction: Acute mental stress and states of anxiety induced to influence psychophysiological reactivity in healthy young people, result in changes in nervous patterns which may be measured in terms of heart rate variability. Objective: Determine the differences in linear parameters for autonomic cardiovascular balance in young individuals at baseline and during the arithmetic computation test. Methods: A non-observational quasi-experimental before-after study without a control group was conducted at the Basic Biomedical Sciences Laboratory of the University of Medical Sciences of Santiago de Cuba. The study population and sample was 10 subjects. The electrocardiographic tracing (5 min) was recorded at rest and then during the arithmetic computation test. Results: Significant differences were found between the two states as to the variables heart rate (p = 0.005), minimum (p = 0.007), maximum (p = 0.005), RR interval (p = 0.005), stress index (p = 0.028), sympathetic index (p = 0.005), low frequencies (p = 0.005), LF/HF ratio (p = 0.005), RMSSD (p = 0.007), NN50 (p = 0.008), pNN50 (p = 0.005), parasympathetic index (p = 0.005) and high frequencies (p = 0.005). Mental stress caused a parasympathetic reduction and uniform sympathetic predominance in all the subjects participating in the study. Conclusions: During the mental stress induced by the arithmetic computation test, the linear dynamic of the autonomic cardiovascular response experiences an increase in sympathetic activity and a reduction in parasympathetic tone, displaying an adaptive response in cardiovascular function regulation by the autonomous nervous system(AU)

Diferencias en los parámetros lineales del balance autonómico basal entre estudiantes de medicina y atletas juveniles de béisbol / Differences in linear parameters of the basal autonomic balance between medical students and young baseball players

RESUMEN Introducción: La modulación autonómica cardiovascular puede ser considerada como una herramienta útil en la determinación del estado fisiológico de la interacción entre los sistemas nervioso autónomo y cardiovascular. Objetivo: Determinar las diferencias en los parámetros lineales del balance autonómico basal entre estudiantes de medicina y atletas juveniles de béisbol. Método: Se realizó un estudio analítico de tipo transversal en el Laboratorio de Ciencias Básicas Biomédicas de la Facultad Nº. 1 de la Universidad de Ciencias Médicas de Santiago de Cuba. Universo y muestra de 36 individuos (Grupo 1: 18 atletas juveniles de béisbol de alto rendimiento, Grupo 2: 18 estudiantes de medicina). Los datos fueron recolectados mediante de polígrafo PowerLab de 8 canales, y fueron procesados usando el software Kubios® versión 3.0.4 Premium. Resultados: Existieron diferencias significativas en los valores de pNN50 (p=0,009), índice de estrés (stress index [p=0,044]), y en los índices parasimpático (p=0,005) y simpático (p=0,001) entre estudiantes y atletas. La capacidad discriminatoria del índice parasimpático para asociarse con la mejor forma física de los atletas fue buena (área bajo la curva 0,784). El punto de corte óptimo por encima del cual el índice parasimpático se asocia al grupo de los atletas, quedó establecido en 0,57. Conclusiones: El índice parasimpático se asoció con el grupo de atletas, lo que evidencia el predominio vagal en la modulación de la actividad cardíaca en los sujetos de este grupo.

ABSTRACT Introduction: Cardiovascular autonomic modulation can be considered a useful tool in determining the physiological state of the interaction between the autonomic nervous system and the cardiovascular system. Objective: To determine the differences in linear parameters of the basal autonomic balance between medical students and young baseball players. Method: A cross-sectional analytical study was carried out in the Biomedical Basic Sciences Laboratory, Faculty No.1, of the Universidad de Ciencias Médicas in Santiago de Cuba. The population and sample consisted of 36 individuals (Group 1: 18 high-performance young baseball athletes, Group 2: 18 medical students). Data was collected using an 8-channel PowerLab polygraph and it was processed using the Kubios® Software version 3.0.4 Premium. Results: There were significant differences in the values between students and athletes: pNN50 (p=0.009), stress index (p=0.044) and in parasympathetic (p=0.005) and sympathetic (p=0.001) indexes. The discriminatory ability of the parasympathetic index to be associated with the best physical fitness of the athletes was good (area under the curve 0.784). The optimum cut-off point above which the parasympathetic index is associated with the group of athletes was set at 0.57. Conclusions: The parasympathetic index was associated with the group of athletes, showing the vagal predominance in the modulation of cardiac activity in the individuals belonging to this group.

Cardiac vagal imbalance to the isometric sustained weight test in adolescents with emotional eating behavior.

PURPOSE: To assess the relationship between emotional eating behavior and heart rate variability in Spanish adolescents during an isometric exercise test. METHODS: Participants included 52 adolescents aged between 13 and 18 years old. Heart rate was continuously recorded at rest (2 minutes) and during the sustained weight test (2 minutes). Linear and nonlinear methods of heart rate variability were assessed and related to the emotional eating behavior divided in two clusters. RESULTS: Statistically significant differences were observed in linear and non-linear parameters of heart rate variability comparing rest and sustained weight test. An increase in the value of emotional eating in overweight adolescents was founded. During the sustained weight test, there were differences between the two emotional eating clusters regarding the variables peak high frequency power, normalized low frequency power, normalized high frequency power, low frequency/high frequency ratio, and sample entropy. A positive correlation between the emotional eating behavior and the peak high frequency power was observed, though the prediction capacity of the high frequency waves is low it is observed that there is a good fit to the regression line. CONCLUSION: Results of this study shows that there was a relationship between vagal tone and emotional eating behavior in adolescents during an isometric exercise, with excessive parasympathetic predominance and sympathetic withdrawal during a physical effort.