Do Chemformers Dream of Organic Matter? Evaluating a Transformer Model for Multistep Retrosynthesis.

Synthesis planning of new pharmaceutical compounds is a well-known bottleneck in modern drug design. Template-free methods, such as transformers, have recently been proposed as an alternative to template-based methods for single-step retrosynthetic predictions. Here, we trained and evaluated a transformer model, called the Chemformer, for retrosynthesis predictions within drug discovery. The proprietary data set used for training comprised ∼18 M reactions from literature, patents, and electronic lab notebooks. Chemformer was evaluated for the purpose of both single-step and multistep retrosynthesis. We found that the single-step performance of Chemformer was especially good on reaction classes common in drug discovery, with most reaction classes showing a top-10 round-trip accuracy above 0.97. Moreover, Chemformer reached a higher round-trip accuracy compared to that of a template-based model. By analyzing multistep retrosynthesis experiments, we observed that Chemformer found synthetic routes, leading to commercial starting materials for 95% of the target compounds, an increase of more than 20% compared to the template-based model on a proprietary compound data set. In addition to this, we discovered that Chemformer suggested novel disconnections corresponding to reaction templates, which are not included in the template-based model. These findings were further supported by a publicly available ChEMBL compound data set. The conclusions drawn from this work allow for the design of a synthesis planning tool where template-based and template-free models work in harmony to optimize retrosynthetic recommendations.

Data Sharing in Chemistry: Lessons Learned and a Case for Mandating Structured Reaction Data.

The past decade has seen a number of impressive developments in predictive chemistry and reaction informatics driven by machine learning applications to computer-aided synthesis planning. While many of these developments have been made even with relatively small, bespoke data sets, in order to advance the role of AI in the field at scale, there must be significant improvements in the reporting of reaction data. Currently, the majority of publicly available data is reported in an unstructured format and heavily imbalanced toward high-yielding reactions, which influences the types of models that can be successfully trained. In this Perspective, we analyze several data curation and sharing initiatives that have seen success in chemistry and molecular biology. We discuss several factors that have contributed to their success and how we can take lessons from these case studies and apply them to reaction data. Finally, we spotlight the Open Reaction Database and summarize key actions the community can take toward making reaction data more findable, accessible, interoperable, and reusable (FAIR), including the use of mandates from funding agencies and publishers.

Factores asociados al miedo a la COVID-19 previo al retorno a clases presenciales en una facultad de Medicina peruana

Objetivo: Determinar los factores asociados al miedo a la COVID-19 en el retorno a clases presenciales en estudiantes de Medicina. Materiales y métodos: Estudio de tipo observacional, analítico y transversal. Por medio de un muestreo por conveniencia, se aplicó un cuestionario a 252 estudiantes de una facultad de Medicina en Huancayo, Perú. Este estuvo conformado por una primera sección de información del estudio y consentimiento informado, luego por una sección de características sociodemográficas y una última que incluía cuestionarios validados y empleados en un contexto similar como el cuestionario de miedo a la COVID-19 (FCV-19S) y aspectos psicológicos como el cuestionario DASS-21, conformado por tres subsecciones, que valoran la depresión, ansiedad y estrés en presencia y nivel. Para determinar la correlación entre las escalas, se utilizó las pruebas de Pearson. Además, se calcularon las razones de prevalencia crudas y ajustadas por medio de modelos lineales generalizados. La significancia fue definida como un valor p <0,05. Resultados: Se obtuvo una media del puntaje de miedo a la COVID-19 de 14,99 ± 6,32 puntos y un 26,98 % de los estudiantes mostraron un nivel alto de miedo. La prevalencia de depresión, ansiedad y estrés fue de 30,95 %, 31,75 % y 28,57 %, respectivamente. En el análisis de regresión crudo, se encontró que los factores asociados al alto miedo fueron la vacunación completa (RPc: 0,64), la depresión (RPc: 1,76), la ansiedad (RPc: 2,42) y el estrés (RPc: 2,22); mientras que, en el análisis de regresión ajustado, la vacunación completa (RPc: 0,65), la confianza en las medidas propuestas por la universidad (RPa: 0,50), la confianza en las medidas del estado (RPa: 1,76) y la ansiedad (RPa: 2,18) fueron los factores asociados al alto miedo. Conclusiones: Estos resultados sugieren que cada institución educativa adquiera medidas y estrategias con el fin de brindar lugares seguros que reduzcan el contagio de la COVID-19 y en los que se pueda desarrollar un ambiente educativo óptimo.

Objective: To identify the factors associated with fear of COVID-19 prior to returning to in-person classes among medical students. Materials and methods: An observational, analytical and cross-sectional study. Through convenience sampling, a questionnaire was administered to 252 students from a medical school in Huancayo, Peru. The questionnaire consisted of a first section comprising the study information and informed consent, another one devoted to the sociodemographic characteristics and a last section which included validated questionnaires used in similar contexts, such as the Fear of COVID-19 Scale (FCV-19S), and a psychological questionnaire, i.e., the DASS-21 questionnaire, made up of three subscales that assess both the presence and level of depression, anxiety and stress. To determine the correlation between the scales, the Pearson correlation coefficient was used. In addition, crude and adjusted prevalence rates were calculated using generalized linear models. The significance was defined as a p value < 0.05. Results: The average fear of COVID-19 score was 14.99 ± 6.32 points and 26.98 % of the students showed a high level of fear. The prevalence of depression, anxiety and stress was 30.95 %, 31.75 % and 28.57 %, respectively. The results of the crude regression analysis indicated that the factors associated with high fear were complete vaccination (cPR: 0.64), depression (cPR: 1.76), anxiety (cPR: 2.42) and stress (cPR: 2.22). Moreover, the results of the adjusted regression analysis revealed that complete vaccination (cPR: 0.65), trust in university policies and guidelines (aPR: 0.50), trust in government policies (aPR: 1.76) and anxiety (aPR: 2.18) were factors associated with high fear. Conclusions: These results suggest that each educational institution should adopt measures and strategies to provide safe places that reduce the spread of COVID-19 and enable the development of an optimal educational environment.

Factores asociados a la anosmia y ageusia en pacientes COVID-19 de una provincia peruana

Objetivo: identificar la presentación clínica y los factores asociados a la anosmia y ageusia en pacientes con la COVID-19 en un centro de salud de una provincia del Perú en el período de 2020-2021. Métodos: estudio transversal analítico a través de los datos del programa COVID-19 del Policlínico Essalud de Jauja - Perú. Se detallaron características sociodemográficas, sintomatología y comorbilidades de los pacientes. A través de un análisis bivariado se identificó los factores asociados a la anosmia y ageusia. Resultados: se identificó a 356 pacientes: 53,1 % fueron mujeres, la edad media fue 48,7 años (±17,8) y 261 (73,3 %) con COVID-19 leve. Del total, el 22,2 % presentó anosmia y 19,9 % ageusia; de los cuales la mayoría fueron menores de 65 años y del sexo femenino. Presentaron síntomas asociados un 86,1 % de los pacientes con anosmia y un 83,1% con ageusia. Los principales factores asociados a la anosmia fueron: la edad menor a 65 años (p=0,027), tos (p<0,001), cefalea (p<0,001), disnea (p<0,001), congestión nasal (p<0,001) y fiebre (p<0,001); y a la ageusia: edad menor a 65 años (p=0,006), tos (p=0,001), cefalea (p<0,001), disnea (p<0,001), congestión nasal (p<0,001) y diarrea (p<0,001). Conclusiones: la anosmia y ageusia son síntomas frecuentes de la COVID-19. La mayoría de pacientes presentaron estos síntomas asociados a los síntomas comunes. Gran parte de los que presentaban anosmia presentaron congestión nasal por lo que es recomendable considerar diferenciarlos al momento de realizar el diagnóstico.

Summary Objective: To identify the clinical presentation and factors associated with anosmia and ageusia in patients with COVID-19 in a health center in a province of Peru for the period 2020-2021. Methods: Cross-sectional analytical study through data from the COVID-19 program of the Essalud Polyclinic in Jauja, Peru. Sociodemographic characteristics, symptoms and comorbidities of the patients were detailed. A bivariate analysis identified the factors associated with anosmia and ageusia. Results: 356 patients were identified: 53.1 % were women, mean age was 48.7 years (±17.8) and 261 (73.3%) with mild COVID-19. Of the total, 22.2% had anosmia and 19.9% ageusia; of which the majority were under 65 and female. Associated symptoms were found in 86.1% of patients with anosmia and 83.1% with ageusia. The main factors associated with anosmia were age younger than 65 years (p=0.027), cough (p<0.001), headache (p<0.001), dyspnea (p<0.001), nasal congestion (p<0.001) and fever (p<0.001); and ageusia: age younger than 65 years (p=0.006), cough (p=0.001), headache (p<0.001), dyspnea (p<0.001), nasal congestion (p<0.001) and diarrhea (p<0.001). Conclusion: Anosmia and ageusia are common symptoms of COVID-19. Most patients had these symptoms associated with common symptoms. Many of those who had anosmia had nasal congestion, so it is advisable to consider differentiating them when making the diagnosis.

De Novo Drug Design Using Reinforcement Learning with Graph-Based Deep Generative Models.

Machine learning provides effective computational tools for exploring the chemical space via deep generative models. Here, we propose a new reinforcement learning scheme to fine-tune graph-based deep generative models for de novo molecular design tasks. We show how our computational framework can successfully guide a pretrained generative model toward the generation of molecules with a specific property profile, even when such molecules are not present in the training set and unlikely to be generated by the pretrained model. We explored the following tasks: generating molecules of decreasing/increasing size, increasing drug-likeness, and increasing bioactivity. Using the proposed approach, we achieve a model which generates diverse compounds with predicted DRD2 activity for 95% of sampled molecules, outperforming previously reported methods on this metric.

Consumption of Galactose by Trypanosoma cruzi Epimastigotes Generates Resistance against Oxidative Stress.

In this study, we demonstrate that Trypanosoma cruzi epimastigotes previously grown in LIT medium supplemented with 20 mM galactose and exposed to sub-lethal concentrations of hydrogen peroxide (100 µM) showed two-fold and five-fold viability when compared to epimastigotes grown in LIT medium supplemented with two different glucose concentrations (20 mM and 1.5 mM), respectively. Similar results were obtained when exposing epimastigotes from all treatments to methylene blue 30 µM. Additionally, through differential centrifugation and the selective permeabilization of cellular membranes with digitonin, we found that phosphoglucomutase activity (a key enzyme in galactose metabolism) occurs predominantly within the cytosolic compartment. Furthermore, after partially permeabilizing epimastigotes with digitonin (0.025 mg × mg-1 of protein), intact glycosomes treated with 20 mM galactose released a higher hexose phosphate concentration to the cytosol in the form of glucose-1-phosphate, when compared to intact glycosomes treated with 20 mM glucose, which predominantly released glucose-6-phosphate. These results shine a light on T. cruzi's galactose metabolism and its interplay with mechanisms that enable resistance to oxidative stress.

Exploring Graph Traversal Algorithms in Graph-Based Molecular Generation.

Here, we explore the impact of different graph traversal algorithms on molecular graph generation. We do this by training a graph-based deep molecular generative model to build structures using a node order determined via either a breadth- or depth-first search algorithm. What we observe is that using a breadth-first traversal leads to better coverage of training data features compared to a depth-first traversal. We have quantified these differences using a variety of metrics on a data set of natural products. These metrics include percent validity, molecular coverage, and molecular shape. We also observe that by using either a breadth- or depth-first traversal it is possible to overtrain the generative models, at which point the results with either graph traversal algorithm are identical.

Comparative Study of Deep Generative Models on Chemical Space Coverage.

In recent years, deep molecular generative models have emerged as promising methods for de novo molecular design. Thanks to the rapid advance of deep learning techniques, deep learning architectures such as recurrent neural networks, variational autoencoders, and adversarial networks have been successfully employed for constructing generative models. Recently, quite a few metrics have been proposed to evaluate these deep generative models. However, many of these metrics cannot evaluate the chemical space coverage of sampled molecules. This work presents a novel and complementary metric for evaluating deep molecular generative models. The metric is based on the chemical space coverage of a reference dataset-GDB-13. The performance of seven different molecular generative models was compared by calculating what fraction of the structures, ring systems, and functional groups could be reproduced from the largely unseen reference set when using only a small fraction of GDB-13 for training. The results show that the performance of the generative models studied varies significantly using the benchmark metrics introduced herein, such that the generalization capabilities of the generative models can be clearly differentiated. In addition, the coverages of GDB-13 ring systems and functional groups were compared between the models. Our study provides a useful new metric that can be used for evaluating and comparing generative models.

Molecular representations in AI-driven drug discovery: a review and practical guide.

The technological advances of the past century, marked by the computer revolution and the advent of high-throughput screening technologies in drug discovery, opened the path to the computational analysis and visualization of bioactive molecules. For this purpose, it became necessary to represent molecules in a syntax that would be readable by computers and understandable by scientists of various fields. A large number of chemical representations have been developed over the years, their numerosity being due to the fast development of computers and the complexity of producing a representation that encompasses all structural and chemical characteristics. We present here some of the most popular electronic molecular and macromolecular representations used in drug discovery, many of which are based on graph representations. Furthermore, we describe applications of these representations in AI-driven drug discovery. Our aim is to provide a brief guide on structural representations that are essential to the practice of AI in drug discovery. This review serves as a guide for researchers who have little experience with the handling of chemical representations and plan to work on applications at the interface of these fields.

Generating carbon schwarzites via zeolite-templating.

Zeolite-templated carbons (ZTCs) comprise a relatively recent material class synthesized via the chemical vapor deposition of a carbon-containing precursor on a zeolite template, followed by the removal of the template. We have developed a theoretical framework to generate a ZTC model from any given zeolite structure, which we show can successfully predict the structure of known ZTCs. We use our method to generate a library of ZTCs from all known zeolites, to establish criteria for which zeolites can produce experimentally accessible ZTCs, and to identify over 10 ZTCs that have never before been synthesized. We show that ZTCs partition space into two disjoint labyrinths that can be described by a pair of interpenetrating nets. Since such a pair of nets also describes a triply periodic minimal surface (TPMS), our results establish the relationship between ZTCs and schwarzites-carbon materials with negative Gaussian curvature that resemble TPMSs-linking the research topics and demonstrating that schwarzites should no longer be thought of as purely hypothetical materials.

Unexpected Diffusion Anisotropy of Carbon Dioxide in the Metal-Organic Framework Zn2(dobpdc).

Metal-organic frameworks are promising materials for energy-efficient gas separations, but little is known about the diffusion of adsorbates in materials featuring one-dimensional porosity at the nanoscale. An understanding of the interplay between framework structure and gas diffusion is crucial for the practical application of these materials as adsorbents or in mixed-matrix membranes, since the rate of gas diffusion within the adsorbent pores impacts the required size (and therefore cost) of the adsorbent column or membrane. Here, we investigate the diffusion of CO2 within the pores of Zn2(dobpdc) (dobpdc4- = 4,4'-dioxidobiphenyl-3,3'-dicarboxylate) using pulsed field gradient (PFG) nuclear magnetic resonance (NMR) spectroscopy and molecular dynamics (MD) simulations. The residual chemical shift anisotropy for pore-confined CO2 allows PFG NMR measurements of self-diffusion in different crystallographic directions, and our analysis of the entire NMR line shape as a function of the applied field gradient provides a precise determination of the self-diffusion coefficients. In addition to observing CO2 diffusion through the channels parallel to the crystallographic c axis (self-diffusion coefficient D∥ = (5.8 ± 0.1) × 10-9 m2 s-1 at a pressure of 625 mbar CO2), we unexpectedly find that CO2 is also able to diffuse between the hexagonal channels in the crystallographic ab plane (D⊥ = (1.9 ± 0.2) × 10-10 m2 s-1), despite the walls of these channels appearing impermeable by single-crystal X-ray crystallography and flexible lattice MD simulations. Observation of such unexpected diffusion in the ab plane suggests the presence of defects that enable effective multidimensional CO2 transport in a metal-organic framework with nominally one-dimensional porosity.

Subcellular localization of glycolytic enzymes and characterization of intermediary metabolism of Trypanosoma rangeli.

Trypanosoma rangeli is a hemoflagellate protist that infects wild and domestic mammals as well as humans in Central and South America. Although this parasite is not pathogenic for human, it is being studied because it shares with Trypanosoma cruzi, the etiological agent of Chagas' disease, biological characteristics, geographic distribution, vectors and vertebrate hosts. Several metabolic studies have been performed with T. cruzi epimastigotes, however little is known about the metabolism of T. rangeli. In this work we present the subcellular distribution of the T. rangeli enzymes responsible for the conversion of glucose to pyruvate, as determined by epifluorescense immunomicroscopy and subcellular fractionation involving either selective membrane permeabilization with digitonin or differential and isopycnic centrifugation. We found that in T. rangeli epimastigotes the first six enzymes of the glycolytic pathway, involved in the conversion of glucose to 1,3-bisphosphoglycerate are located within glycosomes, while the last four steps occur in the cytosol. In contrast with T. cruzi, where three isoenzymes (one cytosolic and two glycosomal) of phosphoglycerate kinase are expressed simultaneously, only one enzyme with this activity is detected in T. rangeli epimastigotes, in the cytosol. Consistent with this latter result, we found enzymes involved in auxiliary pathways to glycolysis needed to maintain adenine nucleotide and redox balances within glycosomes such as phosphoenolpyruvate carboxykinase, malate dehydrogenase, fumarate reductase, pyruvate phosphate dikinase and glycerol-3-phosphate dehydrogenase. Glucokinase, galactokinase and the first enzyme of the pentose-phosphate pathway, glucose-6-phosphate dehydrogenase, were also located inside glycosomes. Furthermore, we demonstrate that T. rangeli epimastigotes growing in LIT medium only consume glucose and do not excrete ammonium; moreover, they are unable to survive in partially-depleted glucose medium. The velocity of glucose consumption is about 40% higher than that of procyclic Trypanosoma brucei, and four times faster than by T. cruzi epimastigotes under the same culture conditions.

Interaction of Trypanosoma evansi with the plasminogen-plasmin system.

Trypanosoma evansi is a widely-distributed haemoflagellated parasite of veterinary importance that infects a variety of mammals including horses, mules, camels, buffalos, cattle and deer. It is the causal agent of a trypanosomiasis known as Surra which produces epidemics of great economic importance in Africa, Asia and South America. The main pathology includes an enlarged spleen with hypertrophy of lymphoid follicles, congested lungs, neuronal degeneration and meningoencephalitis, where migration of the parasites from the blood to the tissues is essential. Most cells, including pathogenic cells, use diverse strategies for tissue invasion, such as the expression of surface receptors to bind plasminogen or plasmin. In this work, we show that T. evansi is able to bind plasminogen and plasmin on its surface. The analysis of this binding revealed a high affinity dissociation constant (Kd of 0.080±0.009µM) and 1×10(5) plasminogen binding sites per cell. Also a second population of receptors with a Kd of 0.255±0.070µM and 3.2×10(4) plasminogen binding sites per cell was determined. Several proteins with molecular masses between ∼18 and ∼70kDa are responsible for this binding. This parasite-plasminogen interaction may be important in the establishment of the infection in the vertebrate host, where the physiological concentration of available plasminogen is around 2µM.

[Adenosine deaminase in experimental trypanosomiasis: future implications]. / Adenosin deaminasa en la tripanosomiasis experimental: futuras implicaciones.

The adenosine deaminase represents a control point in the regulation of extracellular adenosine levels, thus playing a critical role in the modulation of purinergic responses to certain pathophysiological events. Several studies have shown that serum and plasma enzyme levels are elevated in some diseases caused by microorganisms, which may represent a compensatory mechanism due to the elevated levels of adenosine and the release of inflammatory mediators. Recent research indicates that adenosine deaminase activity decreases and affects hematological parameters of infected animals with Trypanosoma evansi, so that such alterations could have implications in the pathogenesis of the disease. In addition, the enzyme has been detected in this parasite; allowing the inference that it could be associated with the vital functions of the same, similar to what occurs in mammals. This knowledge may be useful in the association of chemotherapy with specific inhibitors of the enzyme in future studies.

Systematic Tuning and Multifunctionalization of Covalent Organic Polymers for Enhanced Carbon Capture.

Porous covalent polymers are attracting increasing interest in the fields of gas adsorption, gas separation, and catalysis due to their fertile synthetic polymer chemistry, large internal surface areas, and ultrahigh hydrothermal stabilities. While precisely manipulating the porosities of porous organic materials for targeted applications remains challenging, we show how a large degree of diversity can be achieved in covalent organic polymers by incorporating multiple functionalities into a single framework, as is done for crystalline porous materials. Here, we synthesized 17 novel porous covalent organic polymers (COPs) with finely tuned porosities, a wide range of Brunauer-Emmett-Teller (BET) specific surface areas of 430-3624 m(2) g(-1), and a broad range of pore volumes of 0.24-3.50 cm(3) g(-1), all achieved by tailoring the length and geometry of building blocks. Furthermore, we are the first to successfully incorporate more than three distinct functional groups into one phase for porous organic materials, which has been previously demonstrated in crystalline metal-organic frameworks (MOFs). COPs decorated with multiple functional groups in one phase can lead to enhanced properties that are not simply linear combinations of the pure component properties. For instance, in the dibromobenzene-lined frameworks, the bi- and multifunctionalized COPs exhibit selectivities for carbon dioxide over nitrogen twice as large as any of the singly functionalized COPs. These multifunctionalized frameworks also exhibit a lower parasitic energy cost for carbon capture at typical flue gas conditions than any of the singly functionalized frameworks. Despite the significant improvement, these frameworks do not yet outperform the current state-of-art technology for carbon capture. Nonetheless, the tuning strategy presented here opens up avenues for the design of novel catalysts, the synthesis of functional sensors from these materials, and the improvement in the performance of existing covalent organic polymers by multifunctionalization.

Adenosin deaminasa en la tripanosomiasis experimental: futuras implicaciones / Adenosine deaminase in experimental trypanosomiasis: future implications

La adenosin deaminasa representa un punto de control en la regulación de los niveles extracelulares de adenosina, desempeñando así un papel fundamental en la modulación de las respuestas purinérgicas a ciertos eventos patofisiológicos. Diversos estudios señalan que los niveles séricos y plasmáticos de la enzima se elevan en algunas enfermedades causadas por microorganismos, lo cual podría representar un mecanismo compensatorio como consecuencia de la elevación de las concentraciones de adenosina y la liberación de mediadores inflamatorios. Recientes investigaciones indican que la actividad de la adenosin deaminasa disminuye e influye en los parámetros hematológicos de animales infectados con Trypanosoma evansi, de manera que tales alteraciones podrían tener implicaciones en la patogénesis de la enfermedad. Adicionalmente, la enzima ha sido detectada en este parásito; lo que permite inferir que podría estar asociada a las funciones vitales del mismo, de manera similar a lo que ocurre en los mamíferos. Este conocimiento puede ser útil al asociar la quimioterapia con inhibidores específicos de la enzima en futuros estudios.

The adenosine deaminase represents a control point in the regulation of extracellular adenosine levels, thus playing a critical role in the modulation of purinergic responses to certain pathophysiological events. Several studies have shown that serum and plasma enzyme levels are elevated in some diseases caused by microorganisms, which may represent a compensatory mechanism due to the elevated levels of adenosine and the release of inflammatory mediators. Recent research indicates that adenosine deaminase activity decreases and affects hematological parameters of infected animals with Trypanosoma evansi, so that such alterations could have implications in the pathogenesis of the disease. In addition, the enzyme has been detected in this parasite; allowing the inference that it could be associated with the vital functions of the same, similar to what occurs in mammals. This knowledge may be useful in the association of chemotherapy with specific inhibitors of the enzyme in future studies.

Antígenos parasitarios de O-Glicosilación incompleta: Un enfoque inmunoterapeutico contra el cáncer / Incomplete O-Glycosylation parasite antigens: An immunotherapeutic approach against cancer

Es cada vez mayor la evidencia experimental y clínica de que el sistema inmune interviene activamente en la patogénesis y el control de la progresión tumoral. Una respuesta antitumoral efectiva depende de la correcta interacción de diversos componentes del sistema inmune, como las células presentadoras de antígeno y diferentes sub-poblaciones de células T. Sin embargo, los tumores malignos desarrollan numerosos mecanismos para evadir su reconocimiento y eliminación. Diversos estudios reportan que estructuras asociadas a tumor tales como los antígenos Tn y sialil-Tn se expresan en algunos parásitos protozoarios y helmintos, planteando numerosas interrogantes a nivel de la interacción parásito-hospedador. Considerando que existe una correlación negativa entre ciertas infecciones parasitarias y el desarrollo de cáncer, los antígenos de O-glicosilación incompleta obtenidos de parásitos podrían ser potenciales estructuras miméticas para la inducción de respuestas cruzadas contra antígenos tumorales. Actualmente, el área de la glicobiología del cáncer tiene muchas expectativas para encontrar solución a uno de los grandes problemas de salud que afecta a la población tanto desde el punto de vista económico como social.

There is increasing experimental and clinical evidence that the immune system plays an active role in the pathogenesis and control of tumor progression. An effective antitumor response depends on the correct interaction of the various components of the immune system, such as antigen presenting cells and sub-populations of T cells. However, malignant tumors develop numerous mechanisms to evade recognition and elimination. Several studies report that structures associated with tumors such as Tn and sialyl-Tn antigens are expressed in some protozoan parasites and helminths, thus raising many questions regarding parasite-host interactions. The negative correlation between certain parasite infections and cancer development suggests that antigens from incomplete O-glycosylation obtained from parasites could represent potential mimetic structures for inducing cross responses against tumor antigens. Currently, cancer glycobiology is a promising area in the search for a solution to one of the major health problems affecting the population both from an economic and a social perspective.

El apoyo social asistencial en pacientes reumáticos: impacto de la intervención en México / Institutional social case work in rheumatic patients: impact of the intervention in Mexico

La afección biopsicosocial del paciente reumático puede ser tan grave que requiere de apoyo social asistencial (ASA). Objetivo: Conocer las repercuciones del ASA en pacientes reumáticos de un centro de tercer nivel. Diseño: Estudio descriptivo y transversal. Material y Métodos: Se estudiaron 84 pacientes referidos por reumatólogos para ASA de mayo de 1990 a agosto de 1993. Descripción del ASA: Se aplicó un estudio socioeconómico que evalúa datos generales, ingresos, condiciones de vivienda, de alimentación, relaciones familiares, actitud del paciente, costo del tratamiento, acceso a servicios de salud, incapacidad física y depresión. Se realizó un diagnóstico y en conjunto con el paciente se elaboró un plan de apoyo social. La entrevista tuvo una duración promedio de 30 minutos. Análisis: Se utilizó estadística descriptiva, X², t de Student y análisis multivariado para evaluar las características de aquellos con una respuesta adecuada. Reultados: De los 84 pacientes, 92 por ciento eran de clase socioeconómica baja; 38 por ciento tenían primaria incompleta; 87 por ciento se encontraban incapacitados parcialmente y el 43 por ciento mostró una mala actitud ante el problema. Un 63 por ciento requirió de apoyo económico cuyo costo promedio fue de N$ 4,894. El 65 por ciento resolvió su problema y en el análisis discriminante los factores que predecían éxito del programa de ASA fueron actitud, costo, incapacidad, residencia en el DF, condiciones de alimentación y vivienda, edad menor de 40 años y relaciones familiares adecuadas. Conclusiones: Es importante realizar una buena selección de candidatos para recibir ASA y lograr los mejores resultados. El procedimiento puede causar dependencia hacia el prestador del ASA

La calidad de la atención médica en el Servicio de Reumatología de un centro de tercer nivel vista a través de la satisfacción del paciente

La satisfacción del paciente con la atención médica recibida se debe considerar cuando se evalúa calidad de la atención. Objetivos: a) primario: conocer el grado de satisfacción del paciente con los diversos elementos involucrados en la consulta externa de reumatología de un centro de tercer nivel y b) secundarios: evaluar su relación con las siguientes variables: diagnóstico, capacidad funcional, escolaridad, depresión, tipo de médico (residente vs médico de base) y nivel socio-económico y diseñar estrategias para corregir los problemas que se identifiquen y un programa de seguimiento y evaluación periódicos: Diseño: estudio descriptivo y transversal. Material y métodos: Se aplicó un cuestionario a 220 pacientes al salir de su consulta médica habitual a través de un entrevistador entrenado. El instrumento evaluaba los diversos elementos que a nuestro juicio deben medirse en los diferentes servicios de nuestro departamento, las preguntas se contestaban en su mayoría en escalas visuales análogas de 0-10. Análisis: Se utilizó estadística descriptiva entre grupos se realizó con estadística no paramétrica; se consideró significativo un valor de alfa de 0.05 bimarginal sin ajuste para comparaciones múltiples. resultados: Se encontró en general que el grado de satisfacción con la atención recibida es alto pero significativamente menor para el servicio de recepción (p < 0.05). Los pacientes de menor escolaridad se encontraban más deprimidos, más satisfechos y conocían con menor frecuencia el nombre del médico y su diagnóstico (p < 0.05). Conslusiones: La satisfacción del paciente puede utilizarse para mejorar la calidad de la atención médica; debe fomentarse su detección y atender sugerencias