Abstract INTRODUCTION COVID-19 sequelae, or the short-, medium-, and long-term manifestations of the disease are under continuous study. There are currently few reports on the evolution of hematological variables following a demonstrated absence of SARS-CoV-2 after infection. OBJECTIVE Identify hematological alterations in Cuban adults recovered from SARS-CoV-2 infection, and their relation with disease severity. METHODS We selected 348 persons recovered from COVID-19 residing in Havana, Cuba with an RT-PCR study negative for SARS-CoV-2 performed two weeks after hospital discharge; a structured survey was administered to obtain clinical–epidemiological data. Three groups were established according to COVID-19 clinical criteria: asymptomatic, mild/moderately symptomatic, and severely symptomatic, which, in turn, were divided according to hospital discharge date and blood sample collection date. We performed hemograms with differential leukocyte counts and compared results among groups. We then measured the associations between hematological variables, personal medical history, and relevant lifestyle habits (smoking). RESULTS All hematological variables were within normal reference limits, although men from the group of severely ill patients had increased total leukocytes, neutrophils and lymphocytes, and decreased hemoglobin and eosinophils, which was also evident in those with a recovery time of 31–90 days. CONCLUSIONS The relation between hematological variables and degree of clinical severity offers evidence as to persistence of systemic alterations (possibly inflammatory) associated with viral infection. Their identification and characterization can facilitate personalized patient followup and rehabilitation.

ABSTRACT Introduction: Havana city was the most complex territory at the national level facingthe first outbreak of COVID-19. Its condition of capital, the population density, the limited geographical delimitation between its municipalities, the high inter-municipal and inter-provincial flow of people, added to the fact that it is the province that receives the largest number of travelers from abroad, conferred particularities on this territory. Objective: To determine the main clinical-epidemiological characteristics of patients affected by COVID-19 living in Havana. Methods: An observational, analytical, cross-sectional study was carried out. The sample contained 431 patients, older than one year, with epidemiological discharge from the SARS-CoV-2 infection. To collect information, a questionnaire was applied through an interview. Results: The average age of the sample was 45 years. More than half of the cases evolved in a symptomatic way (not serious or serious). Fever was the most frequent clinical manifestation. The individuals included in the sample, with blood group O or with a background of asthma, showed less risk of presenting symptomatic forms of the disease. Conclusions: The results suggest that age is the main risk factor for developing symptomatic forms (not severe or severe) of COVID-19. On the contrary, blood group O and a history of asthma are protective factors for these forms of clinical evolution.

RESUMEN Introducción: La Habana fue el territorio más complejo a nivel nacional en el enfrentamiento al primer brote de la COVID-19. Su condición de capital, la densidad poblacional, la escasa delimitación geográfica entre sus municipios, el elevado flujo intermunicipal e interprovincial de personas, sumado a que es la provincia que mayor número de viajeros recibe procedentes del extranjero, confirieron a este territorio particularidades en el enfrentamiento a la pandemia. Objetivo: Determinar las principales características clínico-epidemiológicas de pacientes cubanos residentes en La Habana afectados por la COVID-19. Métodos: Se realizó un estudio observacional, analítico, de corte transversal. La muestra quedó formada por 431 pacientes, mayores de un año, de alta epidemiológica de la infección por SARS-CoV-2. Para la recolección de información se aplicó un cuestionario a través de una entrevista. Resultados: La edad promedio de la muestra fue de 45 años. Más de la mitad de los casos evolucionaron de modo sintomático (no grave o grave). La fiebre fue la manifestación clínica más frecuente. Los individuos incluidos en la muestra, con grupo sanguíneo O, o con antecedentes de asma, mostraron menos riesgo de presentar formas sintomáticas de la enfermedad. Conclusiones: Los resultados sugieren que la edad constituye el principal factor de riesgo para desarrollar formas sintomáticas (no graves o graves) de la COVID-19. De modo contrario, el grupo sanguíneo O y el antecedente de asma son factores de protección para estas formas de evolución clínica.

ABSTRACT Introduction: In late 2019, a new coronavirus named Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) that causes respiratory-related illness was reported in Wuhan, China. This virus can attack human lung cells causing a disease called coronavirus disease 2019 (COVID-19), which can lead to pneumonia and acute respiratory distress syndrome. Objective: Describe the structural characteristics of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Methods: A review was written from 47 bibliographic references. Articles and information from national and international journals available in the PubMed, Scopus, Medline, SciELO databases were used. The quality, reliability and validity of the selected articles were analyzed to carry out an adequate review. Analysis-synthesis and logical deduction methods were applied. Development: An introduction to the general aspects of the structure of SARS-CoV-2 is provided by stating the characteristics of the structural and non-structural proteins encoded by the viral genome, which provides the basis for understanding viral entry mechanisms to the host cell, and may be useful to stimulate the search for novel insights and possible therapeutic targets to fight the infection. Conclusions: Knowledge of the structure of the SARS-CoV-2 virus and the characteristics of the structural and non-structural proteins provides the basis for understanding the viral mechanisms of infection and the strategies for developing effective therapeutics.

RESUMEN Introducción: A finales de 2019 se informó el brote de un nuevo coronavirus en Wuhan, China, llamado Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) que causa alteraciones en el aparato respiratorio. Este virus puede atacar las células humanas del pulmón causando una enfermedad denominada enfermedad por coronavirus 2019 (COVID-19), que puede producir neumonía y un síndrome de dificultad respiratoria aguda. Objetivo: Describir las características estructurales del virus SARS-CoV-2. Métodos: Se realizó una revisión bibliográfica a partir de 47 referencias. Se utilizaron artículos e información de revistas nacionales e internacionales disponibles en las bases de datos PubMed, Scopus, Medline, SciELO. Para llevar a cabo una revisión adecuada, se analizaron la calidad, fiabilidad y validez de los artículos seleccionados. Se aplicaron métodos de análisis-síntesis y deducción lógica. Desarrollo: Se proporciona una introducción de los aspectos generales de la estructura del SARS-CoV-2. Se enuncian las características de las proteínas estructurales y no estructurales codificadas por el genoma viral, lo que provee la base para comprender los mecanismos virales de entrada a la célula huésped. El artículo resulta de utilidad para estimular la búsqueda de nuevos conocimientos y posibles objetivos terapéuticos para combatir la infección. Conclusiones: El conocimiento sobre la estructura del virus SARS-CoV-2 y las características de las proteínas estructurales y no estructurales que lo forman ampara significativamente las bases para entender los mecanismos virales de la infección y las estrategias para el desarrollo terapéutico efectivo.

Abstract Introduction: The molecular characteristic features of tumor necrosis factor-alpha (TNFa) (−308A > G) and vascular endothelial growth factor (VEGF) (+405G > C) polymorphisms can be applied to define the number of embryos to be transferred during assisted reproductive procedures, to reduce the risk of multiple pregnancy and implantation failure rates. Objective: The objective of the study was to establish the relationship between individual predisposition in combination with VEGF (+405G > C) and TNFa (−308A > G) genetic polymorphisms and embryonic implantation rates in Cuban patients receiving in vitro fertilization (IVF) treatment. Methods: A cohort study was conducted at the National Centre for Medical Genetics, where 27 patients were evaluated in consultation for infertile couples. The identification of the genotypes was carried out using amplification-refractory mutation system-polymerase chain reaction . The Hardy-Weinberg equilibrium was determined by applying the Chi-square goodness of fit test, and a Principal Component Analysis (PCA) was performed to evaluate the genotypic population structure. Results: Subjects with a VEGF.CC/TNFa.GG variant genotype combination were grouped homogeneously in the PCA model with respect to axis 2, where the frequency of women with a low implantation rate was higher. Patients with a TNFa.AG variant genotype were grouped together, as they presented higher implantation rates. Conclusions: There is a relationship between VEGF.CC and TNFa.GG variant genotypes and a low implantation rate, when they are expressed individually or in combination in patients treated with IVF techniques, whereas the individual TNFa.AG variant genotype is associated with a higher implantation rate.

ABSTRACT Introduction: The vascular endothelial growth factor (VEGF) is a protein involved in the proliferation and cell migration of the vascular endothelium. In its gene, +405G>C Polymorphism has been reported. There are no population genetic reports of this variant in Cuba that allow the characterization of immunogenetic profiles at a molecular level for its application to allelic association studies. Objectives: To describe the genic and genotypic frequencies of the VEGF (+405 G>C) polymorphism in the Cuban population. Material and Methods: A descriptive cross-sectional observational study was carried out from October 2017 to March 2018 in 162 Cuban healthy newborns of both sexes for the neonatal screening for metabolic diseases, whose biological samples were conserved in the DNA bank of the National Center for Medical Genetics. The molecular characterization of the genotypes was carried out using a PCR-ARMS. The GENEPOP 4.4 software and the statistical software package STATISTICA 8.0 were used for the analysis of genic and genotypic frequencies. Results: The population did not adjust to the Hardy-Weinberg equilibrium model for the gene evaluated. The estimated gene frequencies of VEGF +405 G> C polymorphism were 0.33 for the G allele and 0.67 for the C allele. The calculation of the genotypic frequencies resulted in 0.14, 0.37 and 0.49, for the variants GG, GC and CC, respectively. Conclusions: The allelic frequencies of VEGF.C were higher than the frequencies of the VEGF.G allele, being the VEGF GG the least represented genotype in the group studied.

RESUMEN Introducción: El factor de crecimiento endotelial vascular (VEGF) es una proteína involucrada en la proliferación y migración celular del endotelio vascular, en cuyo gen se ha reportado el polimorfismo +405G>C. Se reconoce que no existen reportes genéticos poblacionales de esta variante en Cuba, que permitan caracterizar los perfiles inmunogenéticos a nivel molecular, para su aplicación en estudios de asociación alélica. Objetivo: Describir las frecuencias génicas y genotípicas del polimorfismo VEGF (+405 G>C) en la población cubana. Material y Métodos: Se realizó un estudio observacional, descriptivo, transversal, entre octubre de 2017 y marzo de 2018 en 162 neonatos cubanos, de ambos sexos y sanos, para el pesquisaje neonatal de enfermedades metabólicas, cuyas muestras biológicas se conservaban en el banco de ADN del Centro Nacional de Genética Médica. La caracterización molecular de los genotipos fue realizada mediante un PCR-ARMS. Se utilizó el software GENEPOP 4.4 y el paquete estadístico STATISTICA 8.0 para los cálculos de las frecuencias génicas y genotípicas. Resultados: La población no se ajustó al modelo de equilibrio de Hardy Weinberg para el gen evaluado. Las frecuencias génicas estimadas para el polimorfismo VEGF (+405 G>C) fueron de 0,33 para el alelo G y de 0,67 para el alelo C. El cálculo de las frecuencias genotípicas resultó en 0,14, 0,37 y 0,49, para las variantes GG, GC y CC, respectivamente. Conclusiones: Las frecuencias alélicas VEGF.C fueron superiores a la del alelo VEGF.G, siendo el genotipo VEGF.GG el de menor representación en el conjunto estudiado.

Health promotion constitutes one of the most important health tasks related to the work of the general stomatologist. It is a wider concept than prevention, since it comprises the biological, environmental, social and cultural fields, to mention some, where the political will of the State plays a fundamental role, for rising each day the life quality of the Cuban population regarding oral health. The results related to the promotion are mediate, of higher impact and they generally require an investment in health at long term, contrary to the medical treatments, results of which are faster, but less durable and deep. Taking in consideration these arguments, the present investigation was carried out, aimed at describing the new approaches on the health promotion and to offer a more updated information on the topic.

La promoción de salud constituye una de las acciones sanitarias más importante relacionada con la labor del estomatólogo general. Es un concepto más amplio que la prevención, ya que abarca las esferas biológica, ambiental, social y cultural, por citar algunas, donde la voluntad política del Estado desempeña una función fundamental, en aras de elevar cada día la calidad de vida de la población cubana en materia de salud bucal. Los resultados relacionados con la promoción son mediatos, de mayor impacto y generalmente requieren de una inversión en salud a largo plazo, a diferencia de los tratamientos médicos, cuyos resultados son más rápidos, pero menos duraderos y profundos. Tomando en consideración estos argumentos se llevó a cabo la presente investigación, con vistas a describir los nuevos enfoques sobre la promoción de salud y brindar una información más actualizada sobre el tema.