Low anterior resection with transanal transection and single-stapled anastomosis: technical aspects and initial results.

BACKGROUND: Rectal cancer (RC) is a surgical challenge due to its technical complexity. The double-stapled (DS) technique, a standard for colorectal anastomosis, has been associated with notable drawbacks, including a high incidence of anastomotic leak (AL). Low anterior resection with transanal transection and single-stapled (TTSS) anastomosis has emerged to mitigate those drawbacks. METHODS: Observational study in which it described the technical aspects and results of the initial group of patients with medium-low RC undergoing elective laparoscopic total mesorectal excision (TME) and TTSS. RESULTS: Twenty-two patients were included in the series. Favourable postoperative outcomes with a median length of stay of 5 days and an AL incidence of 9.1%. Importantly, all patients achieved complete mesorectal excision with tumour-free margins, and no mortalities were reported. CONCLUSION: TTSS emerges as a promising alternative for patients with middle and lower rectal tumours, offering potential benefits in terms of morbidity reduction and oncological integrity compared with other techniques.

Is it healthy urban agriculture? Human exposure to potentially toxic elements in urban gardens from Andalusia, Spain.

Different vegetable species and topsoils were collected from different urban gardens of Seville, Cordoba, and Huelva (South Spain) and from two small towns in a mining area (Riotinto), together with topsoil close to the plants. The concentration of potentially toxic elements (PTEs) (As, B, Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, and Zn) was evaluated in edible plant parts and in the soils. The same species were also purchased from Seville local markets and from a peri-urban area (domestic garden in a rural area) and also analyzed. Plant/soil pollution relation was studied and human health risk was assessed by different parameters. Soils of urban gardens from the mining area were more contaminated with As, Cr, Cu, Pb, and Zn in comparison with other locations, and generally, soils from cities showed higher values of As, Pb, and Zn than the peri-urban ones. The mean concentration of almost all potentially toxic elements was higher in leafy than in fruiting and bulbous species. Arsenic, Cd, and Pb concentrations were below health-based guidance values in all vegetables except Cd in one sample in the peri-urban area. In general, PTEs concentration in vegetables from city urban gardens did not exceed the one found in market vegetables for almost all studied elements, except in lettuce for almost elements. The hazard quotient (HQ) values were lower than the unit for all PTEs in plant species from the studied gardens, as well as the hazard index (HI), indicating that consumption of these vegetables can be considered safe and without risk to human health. Also, cancer risk values for As were below the established limits in all vegetables from the studied urban gardens, including those from the As-contaminated soils in the mining area.

Predictive models and applicability of artificial intelligence-based approaches in drug allergy.

PURPOSE OF REVIEW: Drug allergy is responsible for a huge burden on public healthcare systems, representing in some instances a threat for patient's life. Diagnosis is complex due to the heterogeneity of clinical phenotypes and mechanisms involved, the limitations of in vitro tests, and the associated risk to in vivo tests. Predictive models, including those using recent advances in artificial intelligence, may circumvent these drawbacks, leading to an appropriate classification of patients and improving their management in clinical settings. RECENT FINDINGS: Scores and predictive models to assess drug allergy development, including patient risk stratification, are scarce and usually apply logistic regression analysis. Over recent years, different methods encompassed under the general umbrella of artificial intelligence, including machine and deep learning, and artificial neural networks, are emerging as powerful tools to provide reliable and optimal models for clinical diagnosis, prediction, and precision medicine in different types of drug allergy. SUMMARY: This review provides general concepts and current evidence supporting the potential utility of predictive models and artificial intelligence branches in drug allergy diagnosis.

Group 2 innate lymphoid cells are key in lipid transfer protein allergy pathogenesis.

Background: Immunopathology in food allergy is characterized by an uncontrolled type 2 immune response and specific-IgE production. Recent studies have determined that group 2 innate lymphoid cells (ILC2) participate in the food allergy pathogenic mechanism and their severity. Our objective was to investigate the role of ILC2 in peach-allergic patients due to non-specific lipid transfer protein (Pru p 3) sensitization. Methods: The immune response in peripheral blood mononuclear cells was characterized in lipid transfer protein-allergic patients and healthy controls. We have analyzed the Pru p 3 uptake on ILC2, the expression of costimulatory molecules, and their involvement on the T-cell proliferative response and cytokine production under different experimental conditions: cytokines involved in group 2 innate lymphoid cell activation (IL-33 and IL-25), Pru p 3 as main food allergen, and the combination of both components (IL-33/IL-25+Pru p 3) using cell sorting, EliSpot, flow cytometry, and confocal microscopy. Results: Our results show that Pru p 3 allergen is taken up by group 2 innate lymphoid cells, regulating their costimulatory molecule expression (CD83 and HLA-DR) depending on the presence of Pru p 3 and its combination with IL-33/IL-25. The Pru p 3-stimulated ILC2 induced specific GATA3+Th2 proliferation and cytokine (IL-4, IL-5, and IL-13) production in lipid transfer protein-allergic patients in a cell contact-dependent manner with no changes in Tbet+Th1- and FOXP3+Treg cell differentiation. Conclusions: The results indicate that in lipid transfer protein-allergic patients, the responsible allergen, Pru p 3, interacts with group 2 innate lymphoid cells, promoting a Th2 cell response. Our results might be of interest in vivo, as they show a role of group 2 innate lymphoid cells as antigen-presenting cells, contributing to the development of food allergy. Consequently, group 2 innate lymphoid cells may be considered as potential therapeutic targets.

Realism and the point at infinity: The end of the line?

Philosophers of mathematics often rely on the historical progress of mathematics in support of mathematical realism. These histories typically build on formal semantic tools to evaluate the changes in mathematics, and on these bases present later mathematical concepts as refined versions of earlier concepts which are taken to be vague. Claiming that this view does not apply to mathematical concepts in general, we present a case-study concerning projective geometry, for which we apply the tools of cognitive linguistics to analyse the developmental trajectory of the domain. On the basis of this analysis, we argue for the existence of two conceptually incompatible inferential structures, occurring at distinct moments in history, both of which yield the same projective geometric theorems; the first invoked by the French mathematicians Girard Desargues (1591-1661) and Jean-Victor Poncelet (1788-1867), and the second characterising a specific modern mode. We demonstrate that neither of these inferential structures can be considered as a refinement of the other. This case of conceptual development presents an issue to the standard account of progress and its bearing on mathematical realism. Our analysis suggests that the features that distinguish the underlying conceptually incompatible inferential structures are invisible to the standard application of the tools of formal semantics. Thus this case-study stands as an example of the manner and necessity of linguistics-specifically cognitive linguistics-to inform the philosophy of mathematics.

A synthetic glycodendropeptide induces methylation changes on regulatory T cells linked to tolerant responses in anaphylactic-mice.

Introduction: Lipid transfer proteins (LTPs) are allergens found in a wide range of plant-foods. Specifically, Pru p 3, the major allergen of peach, is commonly responsible for severe allergic reactions. The need for new alternatives to conventional food allergy treatments, like restrictive diets, suggests allergen immunotherapy as a promising option. It has been demonstrated that sublingual immunotherapy (SLIT) with synthetic glycodendropeptides, such as D1ManPrup3, containing mannose and Pru p 3 peptides induced tolerance in mice and that the persistence of this effect depends on treatment dose (2nM or 5nM). Moreover, it produces changes associated with differential gene expression and methylation profile of dendritic cells, as well as phenotypical changes in regulatory T cells (Treg). However, there are no works addressing the study of epigenetic changes in terms of methylation in the cell subsets that sustain tolerant responses, Treg. Therefore, in this work, DNA methylation changes in splenic-Treg from Pru p 3 anaphylactic mice were evaluated. Methods: It was performed by whole genome bisulphite sequencing comparing SLIT-D1ManPrup3 treated mice: tolerant (2nM D1ManPrup3), desensitized (5nM D1ManPrup3), and sensitized but not treated (antigen-only), with anaphylactic mice. Results: Most of the methylation changes were found in the gene promoters from both SLIT-treated groups, desensitized (1,580) and tolerant (1,576), followed by the antigen-only (1,151) group. Although tolerant and desensitized mice showed a similar number of methylation changes, only 445 genes were shared in both. Remarkably, interesting methylation changes were observed on the promoter regions of critical transcription factors for Treg function like Stat4, Stat5a, Stat5b, Foxp3, and Gata3. In fact, Foxp3 was observed exclusively as hypomethylated in tolerant group, whereas Gata3 was only hypomethylated in the desensitized mice. Discussion: In conclusion, diverse D1ManPrup3 doses induce different responses (tolerance or desensitization) in mice, which are reflected by differential methylation changes in Tregs.

Analytical Solution to a Third-Order Rational Difference Equation.

Inspired by some open conjectures in a rational dynamical system by G. Ladas and Palladino, in this paper, we consider the problem of solving a third-order difference equation. We comment the conjecture by Ladas. A third-order rational difference equation is solved analytically. The solution is compared with the solution to the linearized equation. We show that the solution to the linearized equation is not good, in general. The methods employed here may be used to solve other rational difference equations. The period of the solution is calculated. We illustrate the accuracy of the obtained solutions in concrete examples.

Multiple models for outbreak decision support in the face of uncertainty.

Policymakers must make management decisions despite incomplete knowledge and conflicting model projections. Little guidance exists for the rapid, representative, and unbiased collection of policy-relevant scientific input from independent modeling teams. Integrating approaches from decision analysis, expert judgment, and model aggregation, we convened multiple modeling teams to evaluate COVID-19 reopening strategies for a mid-sized United States county early in the pandemic. Projections from seventeen distinct models were inconsistent in magnitude but highly consistent in ranking interventions. The 6-mo-ahead aggregate projections were well in line with observed outbreaks in mid-sized US counties. The aggregate results showed that up to half the population could be infected with full workplace reopening, while workplace restrictions reduced median cumulative infections by 82%. Rankings of interventions were consistent across public health objectives, but there was a strong trade-off between public health outcomes and duration of workplace closures, and no win-win intermediate reopening strategies were identified. Between-model variation was high; the aggregate results thus provide valuable risk quantification for decision making. This approach can be applied to the evaluation of management interventions in any setting where models are used to inform decision making. This case study demonstrated the utility of our approach and was one of several multimodel efforts that laid the groundwork for the COVID-19 Scenario Modeling Hub, which has provided multiple rounds of real-time scenario projections for situational awareness and decision making to the Centers for Disease Control and Prevention since December 2020.

Artificial neural network-based heuristic to solve COVID-19 model including government strategies and individual responses.

The current work aims to design a computational framework based on artificial neural networks (ANNs) and the optimization procedures of global and local search approach to solve the nonlinear dynamics of the spread of COVID-19, i.e., the SEIR-NDC model. The combination of the Genetic algorithm (GA) and active-set approach (ASA), i.e., GA-ASA, works as a global-local search scheme to solve the SEIR-NDC model. An error-based fitness function is optimized through the hybrid combination of the GA-ASA by using the differential SEIR-NDC model and its initial conditions. The numerical performances of the SEIR-NDC nonlinear model are presented through the procedures of ANNs along with GA-ASA by taking ten neurons. The correctness of the designed scheme is observed by comparing the obtained results based on the SEIR-NDC model and the reference Adams method. The absolute error performances are performed in suitable ranges for each dynamic of the SEIR-NDC model. The statistical analysis is provided to authenticate the reliability of the proposed scheme. Moreover, performance indices graphs and convergence measures are provided to authenticate the exactness and constancy of the proposed stochastic scheme.

A Cloud-Based Machine Learning Approach to Reduce Noise in ECG Arrhythmias for Smart Healthcare Services.

ECG (electrocardiogram) identifies and traces targets and is commonly employed in cardiac disease detection. It is necessary for monitoring precise target trajectories. Estimations of ECG are nonlinear as the parameters TDEs (time delays) and Doppler shifts are computed on receipt of echoes where EKFs (extended Kalman filters) and electrocardiogram have not been examined for computations. ECG, certain times, results in poor accuracies and low SNRs (signal-to-noise ratios), especially while encountering complicated environments. This work proposes to track online filter performances while using optimization techniques to enhance outcomes with the removal of noise in the signal. The use of cost functions can assist state corrections while lowering costs. A new parameter is optimized using IMCEHOs (Improved Mutation Chaotic Elephant Herding Optimizations) by linearly approximating system nonlinearity where multi-iterative function (Optimized Iterative UKFs) predicts a target's unknown parameters. To obtain optimal solutions theoretically, multi-iterative function takes less iteration, resulting in shorter execution times. The proposed multi-iterative function provides numerical approximations, which are derivative-free implementations. Signals are updated in the cloud environment; the updates are received by the patients from home. The simulation evaluation results with estimators show better performances in terms of reduced NMSEs (normalized mean square errors), RMSEs (root mean squared errors), SNRs, variances, and better accuracies than current approaches. Machine learning algorithms have been used to predict the stages of heart disease, which is updated to the patient in the cloud environment. The proposed work has a 91.0% accuracy rate with an error rate of 0.05% by reducing noise levels.

Impact of Biochar Amendment on Soil Properties and Organic Matter Composition in Trace Element-Contaminated Soil.

The application of biochar as an organic amendment in polluted soils can facilitate their recovery by reducing the availability of contaminants. In the present work, the effect of biochar application to acid soils contaminated by heavy metal spillage is studied to assess its effect on the quantity and composition of soil organic matter (SOM), with special attention given to soil humic acids (HAs). This effect is poorly known and of great importance, as HA is one of the most active components of SOM. The field experiment was carried out in 12 field plots of fluvisols, with moderate and high contamination by trace elements (called MAS and AS, respectively), that are located in the Guadiamar Green Corridor (SW Spain), which were amended with 8 Mg·ha-1 of olive pit biochar (OB) and rice husk biochar (RB). The results indicate that 22 months after biochar application, a noticeable increase in soil water holding capacity, total organic carbon content, and soil pH were observed. The amounts of oxidisable carbon (C) and extracted HAs in the soils were not altered due to biochar addition. Thermogravimetric analyses of HAs showed an increase in the abundance of the most thermostable OM fraction of the MAS (375-650 °C), whereas the HAs of AS were enriched in the intermediate fraction (200-375 °C). Spectroscopic and chromatographic analyses indicate that the addition of biochar did not alter the composition of the organic fraction of HAs, while Cu, Fe, and as were considerably accumulated at HAs.

Transcriptional changes in dendritic cells underlying allergen specific induced tolerance in a mouse model.

To investigate food allergy-tolerance mechanisms induced through allergen-specific immunotherapy we used RNA-Sequencing to measure gene expression in lymph-node-derived dendritic cells from Pru p 3-anaphylactic mice after immunotherapy with glycodendropeptides at 2 nM and 5 nM, leading to permanent tolerance and short-term desensitization, respectively. Gene expression was also measured in mice receiving no immunotherapy (anaphylaxis); and in which anaphylaxis could never occur (antigen-only). Compared to anaphylaxis, the antigen-only group showed the greatest number of expression-changes (411), followed by tolerant (186) and desensitized (119). Only 29 genes changed in all groups, including Il12b, Cebpb and Ifngr1. The desensitized group showed enrichment for genes related to chronic inflammatory response, secretory granule, and regulation of interleukin-12 production; the tolerant group showed genes related to cytokine receptor activity and glucocorticoid receptor binding, suggesting distinct pathways for similar outcomes. We identified genes and processes potentially involved in the restoration of long-term tolerance via allergen-specific immunotherapy, representing potential prognostic biomarkers.

Objetos de aprendizaje para el estudio de la Ontogenia Humana. Argumentación teórica

RESUMEN Introducción: con la apertura a las Tecnologías de la Informática y las Comunicaciones en el país y principalmente en el sistema educacional se han desarrollado estrategias para mejorar la calidad de las clases en las aulas cubanas. Los objetos de aprendizaje constituyen actualmente una poderosa herramienta de apoyo a la docencia por lo que es necesario profundizar en su estudio desde la perspectiva pedagógica. Con el objetivo de argumentar sobre los referentes teóricos de los objetos de aprendizaje para el estudio de la Ontogenia Humana se realizó esta revisión bibliográfica. Desarrollo: la asignatura Ontogenia Humana y SOMA es nueva dentro del plan de estudio, por ello está en pleno desarrollo la creación de medios para el aprendizaje, que se sustenten en la didáctica especial como elemento de la creatividad pedagógica de los profesores, siendo necesario argumentar los referentes teóricos de los objetos de aprendizaje, su evolución en el proceso enseñanza - aprendizaje en las Ciencias Médicas. Caracterización, ventajas y desventajas. Conclusiones: los objetos de aprendizaje brindan la posibilidad a los estudiantes de interactuar y dinamizar los procesos, potenciando las actividades educativas, lo que resulta de gran utilidad para fortalecer los contenidos de Ontogenia Humana.

ABSTRACT Introduction: with the opening to Information Technology and Communications in the country and mainly in the educational system, strategies have been developed to improve the quality of classes in Cuban classrooms. Learning objects are currently a powerful tool to support teaching, so it is necessary to deepen their study from a pedagogical perspective. With the aim of arguing about the theoretical references of learning objects for the study of Human Ontogeny, this bibliographic review was carried out. Development: the subject Human Ontogeny and SOMA is new within the study plan, for this reason the creation of means for learning is in full development, which are based on special didactics as an element of the pedagogical creativity of teachers, being necessary to argue the theoretical references of learning objects, their evolution in the teaching-learning process in Medical Sciences. Characterization, advantages and disadvantages. Conclusions: the learning objects provided the possibility for students to interact and streamline the processes, enhancing educational activities, which is very useful to strengthen the contents of Human Ontogeny.

RESUMO Introdução: com a abertura à Tecnologia da Informação e Comunicações no país e principalmente no sistema educacional, foram desenvolvidas estratégias para melhorar a qualidade das aulas nas salas de aula cubanas. Os objetos de aprendizagem são atualmente uma poderosa ferramenta de apoio ao ensino, pelo que é necessário aprofundar o seu estudo numa perspetiva pedagógica. Como objetivo de discutir os referenciais teóricos dos objetos de aprendizagem para o estudo da Ontogenia Humana, foi realizada esta revisão bibliográfica. Desenvolvimento: a disciplina Ontogenia Humana e SOMA é nova dentro do plano de estudos, por isso a criação de meios de aprendizagem está em pleno desenvolvimento, os quais se baseiam na didática especial como elemento da criatividade pedagógica dos professores, sendo necessário discutir a referenciais teóricos dos objetos de aprendizagem, suaevolução no processo de ensino-aprendizagem em Ciências Médicas. Caracterização, vantagens e desvantagens. Conclusões: os objetos de aprendizagem possibilitaram aos alunos interagir e agilizar os processos, potencializando as atividades educativas, o que é muito útil para fortalecer os conteúdos de Ontogenia Humana.

Methylation changes induced by a glycodendropeptide immunotherapy and associated to tolerance in mice.

Introduction: Allergen-specific immunotherapy (AIT) is applied as treatment to rise tolerance in patients with food allergies. Although AIT is thoroughly used, the underlying epigenetic events related to tolerant induction are still unknown. Thus, we aim to investigate epigenetic changes that could be related to tolerance in dendritic cells (DCs) from anaphylactic mice to lipid transfer proteins, Pru p 3, in the context of a sublingual immunotherapy (SLIT) with a glycodendropeptide (D1ManPrup3) that has demonstrated tolerant or desensitization responses depending on the treatment dose. Methods: Changes in DNA methylation in CpG context were determined comparing Sensitized (Antigen-only) animals and two groups receiving SLIT with the D1ManPrup3 nanostructure (D1ManPrup3-SLIT): Tolerant (2nM D1ManPrup3) and Desensitized (5nM D1ManPrup3), against anaphylactic animals. DNA from lymph nodes-DCs were isolated and then, Whole Genome Bisulphite Sequencing was performed to analyze methylation. Results: Most differentially methylated regions were found on the area of influence of gene promoters (DMPRs). Compared to the Anaphylactic group, the highest value was found in Desensitized mice (n = 7,713 DMPRs), followed by Tolerant (n = 4,091 DMPRs) and Sensitized (n = 3,931 DMPRs) mice. Moreover, many of these epigenetic changes were found in genes involved in immune and tolerance responses (Il1b, Il12b, Il1a, Ifng, and Tnf) as shown by functional enrichment (DCs regulation, B cell-mediated immunity, and effector mechanisms). Discussion: In conclusion, different doses of D1ManPrup3-SLIT induce different DNA methylation changes, which are reflected in the induction of distinct responses, tolerance, or desensitization.

Objetos de aprendizaje para el estudio de la Ontogenia Humana. Argumentación teórica / Learning objects for the study of Human Ontogeny. Theoretical argument

Introducción: con la apertura a las Tecnologías de la Informática y las Comunicaciones en el país y principalmente en el sistema educacional se han desarrollado estrategias para mejorar la calidad de las clases en las aulas cubanas. Los objetos de aprendizaje constituyen actualmente una poderosa herramienta de apoyo a la docencia por lo que es necesario profundizar en su estudio desde la perspectiva pedagógica. Con el objetivo de argumentar sobre los referentes teóricos de los objetos de aprendizaje para el estudio de la Ontogenia Humana se realizó esta revisión bibliográfica. Desarrollo: la asignatura Ontogenia Humana y SOMA es nueva dentro del plan de estudio, por ello está en pleno desarrollo la creación de medios para el aprendizaje, que se sustenten en la didáctica especial como elemento de la creatividad pedagógica de los profesores, siendo necesario argumentar los referentes teóricos de los objetos de aprendizaje, su evolución en el proceso enseñanza–aprendizaje en las Ciencias Médicas. Caracterización, ventajas y desventajas. Conclusiones: los Objetos de Aprendizaje brindan la posibilidad a los estudiantes de interactuar y dinamizar los procesos, potenciando las actividades educativas, lo que resulta de gran utilidad para fortalecer los contenidos de Ontogenia Humana(AU)

Introduction: with the opening to Information Technology and Communications in the country and mainly in the educational system, strategies have been developed to improve the quality of classes in Cuban classrooms. Learning objects are currently a powerful tool to support teaching, so it is necessary to deepen their study from a pedagogical perspective. With the aim of arguing about the theoretical references of learning objects for the study of Human Ontogeny, this bibliographic review was carried out. Development: the subject Human Ontogeny and SOMA is new within the study plan, for this reason the creation of means for learning is in full development, which are based on special didactics as an element of the pedagogical creativity of teachers, being necessary to argue the theoretical references of learning objects, their evolution in the teaching-learning process in Medical Sciences. Characterization, advantages and disadvantages. Conclusions: the Learning Objects provided the possibility for students to interact and streamline the processes, enhancing educational activities, which is very useful to strengthen the contents of Human Ontogeny(EU)

The perception of quantity ain't number: Missing the primacy of symbolic reference.

Clarke and Beck's defense of the theoretical construct "approximate number system" (ANS) is flawed in serious ways - from biological misconceptions to mathematical naïveté. The authors misunderstand behavioral/psychological technical concepts, such as numerosity and quantical cognition, which they disdain as "exotic." Additionally, their characterization of rational numbers is blind to the essential role of symbolic reference in the emergence of number.

Epigenetics in Food Allergy and Immunomodulation.

Food allergy (FA) is an increasing problem worldwide and, over recent years, its prevalence is rising in developed countries. Nowadays, the immunological and cellular processes that occur in the allergic reactions are not fully understood, which hampers the development of in vitro diagnostic tools and further treatment options. Moreover, allergic diseases could be reinforced by environmental exposure and genetic modifications. Gene expression can be controlled by different epigenetic mechanisms like DNA methylation, histone modifications, and microRNAs. In addition, several environmental factors such as dietary components (vitamin D, butyrate, folic acid) are able to regulate this epigenetic mechanism. All these factors produce modifications in immune genes that could alter the development and function of immune cells, and therefore the etiology of the disease. Furthermore, these epigenetic mechanisms have also an influence on immunomodulation, which could explain sustained responsiveness or unresponsiveness during immunotherapy due to epigenetic modifications in key genes that induce tolerance in several FA. Thus, in this review we focus on the different epigenetic mechanisms that occur in FA and on the influence of several dietary components in these gene modifications.

Bases informacionales para el estudio morfométrico de placentas en embarazos gemelares

RESUMEN Introducción: En Cuba existen muy pocos estudios morfofuncionales de placentas procedentes de embarazos gemelares que permitan establecer un patrón morfométrico general. Implementar estas bases informacionales contribuiría a perfeccionar las acciones del Programa Nacional de Salud Sexual y Reproductiva en el país. Objetivo: Sistematizar información sobre estudios morfométricos en placentas gemelares para construir la base epistémica de la caracterización del patrón morfométrico de las placentas gemelares y su relación con la corionicidad, la función de este órgano y el grado de bienestar fetal y neonatal. Método: Se aplicó una estrategia de búsqueda en el período enero de 2020 hasta abril de 2021, en bases de datos internacionales (Medline, EMBASE, LILACS, Scopus, Google Académico) para la revisión bibliográfica, mediante la utilización del método de análisis y crítica de las fuentes desde el procedimiento de análisis de contenido. Se empleó un algoritmo para la toma de decisiones en torno a la pertinencia, actualidad novedad y aportes. Resultados: Se hallaron 16 fuentes bibliográficas sobre el tema de investigación, entre ellas: solo una tesis (6,25 %) y 4 textos editados (25 %). Predominaron los artículos científicos (68,75 %) de los últimos cinco años (93,75 %). Todas las fuentes contribuyeron a la construcción de los referentes teóricos. Conclusiones: El estudio morfométrico de la placenta en embarazos gemelares es un área insuficientemente desarrollada en el conocimiento de las ciencias básicas biomédicas, dada la escasa producción bibliográfica sobre el tema.

ABSTRACT Introduction: In Cuba there are very few morphofunctional studies of placentas from twin pregnancies that allow establishing a general morphometric pattern. Implementing these informational databases would help to improve the actions of the National Sexual and Reproductive Health Program in the country. Objective: To systematize information on morphometric studies in twin placentas to build the epistemic basis for the characterization of the morphometric pattern of twin placentas and its relationship with chorionicity, the function of this organ and the degree of fetal and neonatal well-being. Method: A search strategy was applied in the period January 2020 to April 2021, in international databases (Medline, EMBASE, LILACS, Scopus, Google Scholar) for the bibliographic review, using the analysis and criticism method. of the sources from the content analysis procedure. An algorithm was used to make decisions about relevance, news, news and contributions. Results: 16 bibliographic sources were found on the research topic, among them: only one thesis (6.25%) and 4 edited texts (25.0%). Scientific articles (68.75%) from the last five years (93.75%) predominated. All the sources contributed to the construction of the theoretical referents. Conclusions: The morphometric study of the placenta in twin pregnancies is an insufficiently developed area in the knowledge of basic biomedical sciences, given the scarce bibliographic production on the subject.

RESUMO Introdução: Em Cuba existem poucos estudos morfofuncionais de placentas de gestações gemelares que permitam estabelecer um padrão morfométrico geral. A implementação desses bancos de dados informativos ajudaria a melhorar as ações do Programa Nacional de Saúde Sexual e Reprodutiva no país. Objetivo: Sistematizar informações sobre estudos morfométricos em placentas gêmeas para construir a base epistêmica para a caracterização do padrão morfométrico de placentas gêmeas e sua relação com a corionicidade, a função desse órgão e o grau de bem-estar fetal e neonatal. Método: Foi aplicada uma estratégia de busca no período de janeiro de 2020 a abril de 2021, em bases de dados internacionais (Medline, EMBASE, LILACS, Scopus, Google Scholar) para a revisão bibliográfica, utilizando o método de análise e crítica das fontes da análise de conteúdo procedimento. Um algoritmo foi usado para tomar decisões sobre relevância, notícias, notícias e contribuições. Resultados: Foram encontradas 16 fontes bibliográficas sobre o tema da pesquisa, entre elas: apenas uma tese (6,25%) e 4 textos editados (25,0%). Predominaram artigos científicos (68,75%) dos últimos cinco anos (93,75%). Todas as fontes contribuíram para a construção dos referentes teóricos. Conclusões: O estudo morfométrico da placenta em gestações gemelares é uma área pouco desenvolvida no conhecimento das ciências biomédicas básicas, dada a escassa produção bibliográfica sobre o assunto.