Resumen Las verrugas plantares son una patología común en la población. Estas lesiones son a menudo dolorosas y recidivantes. Entre los tratamientos más utilizados están las terapias tópicas destructivas y menos frecuentemente el tratamiento quirúrgico. Sin embargo, con frecuencia recurren, por lo que representan un desafío para el dermatólogo. Presentamos 3 casos de pacientes varones adultos con verrugas plantares recalcitrantes que fueron tratadas exitosamente con una sola sesión de láser PDL, sin recidiva luego de 8 a 12 meses de seguimiento.

Abstract Plantar warts are a common pathology in the population. These lesions are often painful and recurring. Among the most used treatments are topical destructive therapies, and less frequently, surgical treatment. However, they frequently recur, so they represent a challenge for the dermatologist. We present 3 adult males with a recalcitrant plantar wart that were successfully treated with a single PDL laser session, without relapse after 8-12 months of follow-up.

Abstract This paper discussed the synthesis of LTA zeolite from Pinheiro clay (PIN) aiming for adsorption of CO2. To obtain the LTA-PIN zeolite, the PIN was submitted to acid treatment, followed by calcination and hydrothermal treatment. These treatments promoted the reorganization of the crystalline structure of the PIN, leading to the LTA-PIN zeolite with 95.79% purity confirmed by XRD, SEM, XRF, and FTIR results. The performance of the LTA-PIN zeolite was similar to the one of the standard LTA zeolite. The CO2 adsorption by the zeolites could be properly described by the pseudo-second-order kinetic and Freundlich isotherm models, suggesting that physisorption was the main mechanism responsible for the deposition of CO2 at the surface of the zeolites. According to regeneration results, LTA-PIN zeolite can be reused five times without significant loss of CO2 adsorption capacity, contrary to the 12% reduction in CO2 adsorption capacity presented by the LTA-standard zeolite.

Resumen Objetivo: Proponer una clasificación preoperatoria a los pacientes con Tumor de Cuerpo Carotídeo y relacionarlos con complicaciones postoperatorias. Material y métodos: Todos los pacientes operados con diagnóstico de Tumor del Cuerpo Carotídeo entre el 2005 al 2014 en el Hospital Obrero N° 1 de la Caja Nacional de Salud en La Paz - Bolivia Resultados: Se analizaron y operaron 115 pacientes con un promedio de edad de 52 años (DE±11,725 y una moda de 57 años) de los cuales el 109 (94,80%) correspondieron al género femenino con una razón de 18:1. Todos los pacientes eran originarios y residentes de ciudades ubicadas a más de 2500 m.s.n.m. El promedio de evolución fue de 3 años (DE±2,189), y solo 7 pacientes (6,1%) presentan hábito tabáquico. 83 pacientes (72,2%) de los TCC se localizan en el lado izquierdo En las manifestaciones clínicas, todos los pacientes presentan el tumor localizado en el ángulo mandibular, por delante del músculo esternocleidomastoideo, describiéndose un crecimiento paulatino y permanente en 72 sujetos (62,6%), cefalea en 45 (39,1 %), presencia de latido en 30 sujetos (26,1 %), disfagia en 9 (7,9%), mareos en 16 (13,9%) y disfonía en 6 (5,2%). Entre los signos más evidentes de TCC, se describe el signo de Fontaine en 114 sujetos (99,2%), adenomegalia en 20 (17,4%) y otros menos frecuentes como soplo, abombamiento parafaringeo y compromiso de pares craneales. Todos los pacientes fueron clasificados en ambos sistemas (Shamblin y la nuestra llamada de los Andes). Se describen 39 pacientes (33,2%) con complicaciones postoperatorias, Grado I: 1 paciente sin complicaciones; Grado II: de 58 sujetos, 4 (3,5%) presentaban parálisis temporal del Hipogloso; en el Grado III: De los 41 sujetos, 24 (20,8%) presentaron ligadura de la arteria carótida externa, parálisis del hipogloso y glosofaringeo, lesión de recurrente y del laríngeo superior. En el grupo IV, de los 15 sujetos operados, 11 presentaron complicaciones (9,6% del total y 73% del grupo) entre las cuales están ligadura de la arteria carótida externa, lesión del hipogloso y un paciente con AVC y hemiparesia. Se describe una reoperación (0,86%) y ninguna mortalidad. Conclusión: Proponer una clasificación preoperatoria que tenga la posibilidad de asociarse a complicaciones y pronóstico.

Abstract Objective: To propose a preoperative classification of patients with Carotid Body Tumor and relate them to postoperative complications. Material and methods: All patients operated with a diagnosis of Carotid Body Tumor between 2005 and 2014 at the Obrero Hospital No. 1 of the National Health Fund in La Paz - Bolivia Results: 115 patients with an average age of 52 years (SD±11.725 and a mode of 57 years) were analyzed and operated on, of which 109 (94.80%) corresponded to the female gender with a ratio of 18: 1. All the patients were from and residents of cities located more than 2,500 meters above sea level. The mean evolution was 3 years (SD±2.189), and only 7 patients (6.1 %) had a smoking habit. 83 patients (72.2%) of CBTs are located on the left side In the clinical manifestations, all patients present the tumor located in the mandibular angle, in front of the sternocleidomastoid muscle, describing a gradual and permanent growth in 72 subjects (62.6%), headache in 45 (39.1 %), presence ofheartbeat in 30 subjects (26.1 %), dysphagia in 9 (7.9%), dizziness in 16 (13.9%) and dysphonia in 6 (5.2%). Among the most obvious signs of CBT, the Fontaine sign is described in 114 subjects (99.2%), adenomegaly in 20 (17.4%) and other less frequent signs such as murmur, parapharyngeal bulging and cranial nerve involvement. All patients were classified in both systems (Shamblin and ours called from the Andes). 39 patients (33.2%) with postoperative complications were described, Grade I: 1 patient without complications; Grade II: of 58 subjects, 4 (3.5%) had temporary hypoglossal paralysis; in Grade III: Of the 41 subjects, 24 (20.8%) presented external carotid artery ligation, hypoglossal and glossopharyngeal paralysis, recurrent lesión and superior larynx. In group IV, of the 15 operated subjects, 11 presented complications (9.6%of the total and 73% o f the group), among which are external carotid artery ligation, hypoglossal injury and one patient with stroke and hemiparesis. A reoperation (0.86%) and no mortality are described. Conclusión: Propose a preoperative classification that has the possibility of being associated with complications and prognosis.

Background: Transmitted drug resistance (TDR) occurs in patients with HIV infection who are not exposed to antiretroviral drugs but who are infected with a virus with mutations associated with resistance. Aim: To determine the prevalence of TDR and characterize HIV reverse transcriptase and protease mutation patterns. Material and Methods: HIV infected antiretroviral treatment-naive patients treated in three centers between 2014 and 2018 were studied. A genotyping study was carried out. The HIVdb Program (Stanford University) and the World Health Organization (WHO) TDR surveillance mutation list were used to register resistance-associated mutations. Results: We enrolled 220 patients aged a median of 29 (interquartile range (IQR) 24-34) years, 99% men. Median CD4 count was 365 cells/μL (IQR 250-499 cells/μL) and median viral load was 39.150 copies/mL (IQR 9,270 −120,000). The overall prevalence of RTD was 10.45% (95% CI 6.7-15.2, N = 23/220). The higher frequency of TDR was against non-nucleoside reverse transcriptase inhibitors, reaching 9.0% (95% CI 5.6-13.6), followed by nucleoside reverse transcriptase inhibitors reaching 1.8% (95% CI 0.49-4.5) and protease inhibitors reaching 0.45% (95% CI 0.01-2.5). The mutations in reverse transcriptase were M41L, L210W, D67N, K70E, M184V, K103N (6.36%, 95% CI 3.5-10.4), G190A, E138A, K101E, and I84V in protease. Conclusions: These results should prompt a change in recommendations for starting antiretoviral therapy, especially in first-line regimens that include non-nucleoside reverse transcriptase inhibitors.

Resumo Falsa pega é a denominação dada ao enrijecimento prematuro anormal do cimento em poucos minutos após a adição de água. Alguns fatores podem ocasionar falsa pega no cimento Portland CPI-S-32, por exemplo, concentração de álcalis no cimento, formação de alita (C3S) com baixa reatividade e temperatura e tempo de armazenamento do cimento nos silos. O aumento da temperatura causa a desidratação do sulfato de cálcio di-hidratado formando o hemi-hidrato (CaSO4.0,5H2O) ou anidrita (CaSO4), que causa a falsa pega. Assim, neste trabalho foi avaliada a influência da temperatura de armazenamento do clínquer (100, 105, 110, 120 e 130 °C) combinada com o tempo de armazenamento do cimento (30, 60 e 120 min) no comportamento de falsa pega do CPI-S-32. Foi verificado que temperatura de armazenamento acima de 110 °C e tempo de armazenamento acima de 60 min são condições que favorecem a falsa pega do cimento CPI-S-32. Análises físico-químicas, TG/DTG, FRX e DRX foram utilizadas como análises complementares aos ensaios de falsa pega do CPI-S-32.

Abstract The false setting is when cement stiffens prematurely in a few minutes after adding water. Some variables could cause false setting in CPI-S-32 Portland cement, for example, alkali concentration in the cement, the formation of alite (C3S) with low reactivity, and cement storage temperature and time in silos. Temperature increases cause calcium sulfate dihydrate to dehydrate, forming hemihydrate (CaSO4.0.5H2O) or anhydrite (CaSO4), which causes the false setting. In this study, the influence of cement storage temperature (100, 105, 110, 120, and 130 °C) combined with the cement storage time (30, 60, and 120 min) in a silo was studied regarding the CPI-S-32 false setting behavior. It was verified that temperatures above 110 °C and storage time above 60 min are conditions that favor the false setting of CPI-S-32 cement. Physicochemical analysis, TG/DTG, XRF, and XRD were applied as complementary analyzes for the false setting assays of CPI-S-32.

RESUMEN: El propósito del presente estudio fue identificar los secretos entre camarillas de un establecimiento hospitalario. Los hallazgos del presente estudio resaltan la importancia de la etnografía encubierta, mostrando los secretos de estos grupos. Se reportan dos casos relacionados, uno sobre choque séptico y otro sobre una cirugía no especializada, que afectaron la salud de los respectivos pacientes. Se demostró que el secreto compartido y la confianza mutua entre camarillas, conforman plenas agrupaciones cohesionadas en una organización, pues ellas protegen mutuamente sus secretos, resguardando información substancial y poniendo en peligro, incluso, la vida de otros individuos.

ABSTRACT: The purpose of the present study was to identify the secrets between cliques of a hospital establishment. The findings of the present study highlight the importance of covert ethnography, showing the secrets of these groups. Two related cases are reported, one on septic shock and the other on unspecialized surgery, which affected the health of the respective patients. It was shown that shared secrecy and mutual trust between cliques form full cohesive groups in an organization, since they mutually protect their secrets, safeguarding substantial information and even endangering the lives of other individuals.

RESUMO O objetivo do presente estudo foi identificar os segredos entre panelinhas de um estabelecimento hospitalar. Os achados do presente estudo destacam a importância da etnografia encoberta, mostrando os segredos desses grupos. São relatados dois casos relacionados, um em choque séptico e outro em cirurgia não especializada, que afetou a saúde dos respectivos pacientes. Foi demonstrado que o segredo compartilhado e a confiança mútua entre as panelinhas formam grupos coesos completos em uma organização, uma vez que protegem mutuamente seus segredos, salvaguardando informações substanciais e até colocando em risco a vida de outras pessoas.

Resumo O sulfametoxazol (SMX) é um antibiótico amplamente usado no tratamento de doenças e infecções e é frequentemente detectado em ecossistema de águas superficiais. Assim, este trabalho avaliou a capacidade de remoção deste antibiótico de sistemas aquosos utilizando argila Pirangi (PIR) do estado de Sergipe (Brasil). Amostras de argila Pirangi foram tratadas termicamente a 100, 400 e 600 °C e posteriormente modificadas com surfactante catiônico HDTMA. A modificação realizada baseou-se na organização em camadas da argila mineral possibilitando intercalação de surfactante catiônico, atribuindo caráter hidrofóbico à argila. A argila Pirangi tratada termicamente a 100 °C organofílica (org-PIR-100) apresentou maior capacidade máxima de adsorção de 27,3 mg.g-1 com remoção de 90% do SMX em 100 min e pH 6, seguindo o modelo de pseudossegunda ordem e isoterma de Langmuir. As argilas foram caracterizadas por FRX, FTIR, DRX, TG/DTG e BET, confirmando que as moléculas do surfactante foram incorporadas na superfície da argila e que a org-PIR-100 apresentou potencial para o uso em filtros de estações de tratamento de água.

Abstract Sulfamethoxazole (SMX) is a widely-used antibiotic in human and veterinary medicine for treating diseases and infections and is often detected in the surface water ecosystem. Thus, this study evaluated the capacity of removing SMX from aqueous systems using Pirangi clay (PIR) from the state of Sergipe (Brazil). Pirangi clay samples were treated at 100, 400 and 600 °C and modified with hexadecyltrimethylammonium (HDTMA) cationic surfactant. The modification process used was based on the layered organization of the mineral clay, allowing the intercalation of cationic surfactant, giving a hydrophobic character to the clay. The Pirangi clay treated at 100 °C and modified with HDTMA (org-PIR-100) showed adsorption capacity of 27.3 mg.g-1 with 90% removal of the SMX in 100 min and pH 6, following the pseudo-second-order model and Langmuir isotherm. Different characterization methods were employed to characterize the clays, such as XRF, FTIR, XRD, thermogravimetric analyzes (TG/DTG) and BET method, confirming that the surfactant molecules were incorporated on the clay surface and that org-PIR-100 showed potential for use in water treatment plant filters.

SUMMARY: The sphenoidal tubercle is a bone elevation located in the anterior edge of the infratemporal crest of the sphenoid greater wing, where the temporal and lateral pterygoid muscles have their origin. This bone accident presents varied morphology so its description and denomination are a topic of discussion. 60 dry skulls obtained from the morphology laboratory of the Biomedical Basic Sciences Department of the University of Talca were used for a morphological and morphometric analysis of the sphenoidal tubercle including its morphology, diameters (anteroposterior, transverse and vertical) and the distance to the grooves for the maxillary artery and maxillary nerve. Sphenoidal tubercle had a prevalence of 98.4 % of all dry skulls analyzed with a bilateral presentation in the 76.6 % of the cases. According to its different forms of presentation established by Cáceres et al., (2016) the pyramidal form was the most frequent with a 25.7 %. The average diameters were of 4.12 mm anteroposterior, 5.50 mm transverse and 3.89 mm vertical. The average distance to the grooves of the maxillary artery and maxillary nerve were 9.04 mm and 7.6 mm, respectively. Sphenoidal tubercle is a constant bone accident with a variated morphology and measures. Due to its anatomical relations with important neurovascular elements such as the maxillary artery and the maxillary nerve, it may be used as a reference point for surgical access to the infratemporal fossa. From this analysis we establish that the denomination of “infratemporal process” is more accurate, because the development of this bone accident is from muscular traction performed by the lateral pterygoid muscle and the deep portion of the temporal muscle causing great variations in its morphology, probably due to external and functional parameters or even influenced by the biotype.

RESUMEN: El tubérculo esfenoidal es una elevación ósea ubicada en el extremo anterior de la cresta infratemporal del ala mayor del hueso esfenoides, donde presta inserción al músculo temporal y pterigoideo lateral. Presenta morfología variada, por lo que su descripción y denominación resultan motivo de discusión. 60 cráneos secos obtenidos del Laboratorio de Morfología del Departamento de Ciencias Básicas Biomédicas de la Universidad de Talca, fueron utilizados para realizar un análisis morfológico y morfométrico del tubérculo esfenoidal evaluando forma, diámetros (anteroposterior, laterolateral y vertical) y distancia con el surco de la arteria y nervio maxilar. El tubérculo esfenoidal tuvo una prevalencia del 98,4 % del total de cráneos analizados, presentándose bilateralmente en el 76,6 % de los casos. De acuerdo a las diferentes formas de presentación establecidas por Cáceres et al (2016) la forma piramidal fue la más frecuente con un 25,7 %. Los diámetros promedio fueron de 4,12 mm anteroposterior, 5,50 mm laterolateral y 3,89 mm vertical. Las distancias promedio con el surco de la arteria y nervio maxilar fueron de 9,04 mm y 7,6mm, respectivamente. El tubérculo esfenoidal es un accidente óseo constante de morfología y dimensiones variadas. Debido a sus relaciones con elementos vasculares de importancia, tales como la arteria y nervio maxilar, podría ser utilizado como elemento de referencia para el acceso quirúrgico a la fosa infratemporal. A partir de su análisis planteamos que su denominación como “proceso infratemporal” sería más apropiado, debido a que se desarrollaría a partir de la tracción muscular ejercida por el musculo pterigoideo lateral y la porción profunda del músculo temporal, ocasionando variaciones notables en su morfología, probablemente debido a factores externos y funcionales o incluso influenciada por el biotipo.

En respuesta a la necesidad de generar alternativas que permitan asegurar la calidad y diferenciación del café de Nariño, se realizó esta investigación con el objetivo de evaluar la calidad física y sensorial del café variedad Colombia, fruto rojo, sembrado a plena exposición solar por caficultores del programa Nespresso AAA 2015, en diferentes altitudes y variaciones en el beneficio, en el Municipio de la Unión, Nariño. En cada finca se cosecharon diez kilos de café maduro con color rojo intenso, se procesaron con beneficio húmedo en la misma finca, se secaron con diferentes tiempos de exposición solar y se llevaron al laboratorio de Almacafé para evaluar sus características físicas y organolépticas como: aroma, fragancia, acidez, cuerpo, sabor, sabor residual, balance, taza limpia, dulzor y puntaje del catador. Igualmente se analizaron las relaciones de los factores climáticos y agronómicos de cada finca con la calidad de taza. Toda la información se analizó mediante análisis multivariado de componentes principales (ACP) y análisis de correspondencias múltiples (ACM). Se concluyó que las condiciones de altitud, no están asociadas particularmente con los parámetros de calidad de la bebida del café; menores contenidos de fósforo en el suelo, menor tiempo de fermentación (16 - 17h) y secado (20 - 25h de sol), se asociaron a mayores puntajes de calidad. La compleja interacción de todas las variables asociadas a la producción del café, es la que define al final, la calidad de taza.

In response to the need of generating alternatives to ensure the quality and differentiation of the Nariño coffee, this work was carried out with the objective of evaluating the physical and sensory quality of coffee variety Colombia, red fruit, sown to full sunlight by growers of Nespresso AAA program 2015, growing at different altitudes with variations in the coffee post-harvest, in the municipality of La Union, Nariño. Ten kilos of coffee fruit were harvested per farm; these fruits were processed through wet benefit and dried under different solar exposure times, and then were carried to the Almacafé laboratory to assess their physical and organoleptic characteristics such as: aroma, fragrance, acidity, body, taste, residual flavor, balance, clean cup, sweetness and score of taster. It was also analyzed the relationships between climatic and agronomic factors in each farm with the cup quality. The data were analyzed by multivariate analysis of principal components (PCA) and multiple correspondence analyses (ACM). The altitudes are not particularly associated with the quality parameters of the coffee drink; lower contents of P, less time of fermentation (16 - 17h) and drying (20 - 25h of sun), were associated with higher scores of quality. The complex interaction of all the variables associated to the coffee production of, is what defines, the cup quality.

Diversos casos de reação álcalis-sílica têm sido diagnosticados em estruturas de concreto nas quais foram utilizadas rochas graníticas. No entanto, este tipo de rocha é geralmente considerado como inócuo ou de reactividade pouco provável aos álcalis. As rochas graníticas são amplamente exploradas no norte e centro de Portugal, representando quase metade da produção total de agregados no país. O Projeto IMPROVE surgiu da necessidade de diagnosticar corretamente a potencial reatividade aos álcalis de granitos. No âmbito desse projeto foram estudadas diversas amostras colhidas em diferentes regiões de Portugal, apresentando-se neste artigo os resultados de oito destas. Os ensaios realizados incluem a caracterização petrográfica dos agregados e ensaios de expansão de barra de argamassa e prisma de concreto. Concluiu-se que o conteúdo em quartzo microcristalino se correlaciona melhor com os resultados do ensaio em prisma de concreto RILEM AAR-4.1 do que com os outros ensaios de expansão.

Several cases of alkali-silica reaction involving granitic aggregates have been diagnosed in damaged concrete structures in Portugal. Nonetheless, this kind of rock is usually regarded as slow/late reactive or even non-reactive to alkalis. Granitic rocks are widely exploited in Northern and Central Portugal, representing almost half of the produced aggregates in this country. Project IMPROVE rose from the need to accurately diagnose the potential reactivity of granites to alkalis. The study involved about forty granites collected from different regions in Portugal, from which the results of eight samples are being presented in this paper. The tests carried out include the petrographic analyses of the aggregates and mortar and concrete expansion tests. It was concluded that the content of microcrystalline quartz correlates better with the results of AAR-4.1 than with the other expansion tests.

We performed an epidemiological survey to healthcare personnel in Ayacucho Regional Hospital and healthcare centers (Huamanga Micro-Network) with respect to work exposure to hepatitis C virus (VHC), and we performed an ELISA test in sera in order to detect antibodies against the aforementioned virus. 320 of 518 healthcare workers participated, representing 44,1% (165/354) of hospital healthcare workers and 100% (164) of the Micro-Network health centers personnel. No sample was found to be positive, but 211 (65,9%) healthcare workers recognized having at least one working accident (69,2% at the hospital and 62,8% in the Micro-Network); 182 of the accidents (56,9%) involved percutaneous exposure; and 55,3% of the exposures were related to blood. As a conclusion, we did not find hepatitis C virus infection in healthcare workers; however, there is a high risk for infection because of having so many working accidents; so there is a need for implementing a labor risk prevention and management program.

Se efectuó una encuesta epidemiológica al personal de salud del Hospital Regional de Ayacucho y al personal de los establecimientos de salud de su jurisdicción (Microrred Huamanga), sobre la exposición laboral al virus de la hepatitis C (VHC); se realizó ELISA en suero para detectar anticuerpos contra el VHC. Participaron 320 de 518 trabajadores en total, representando 44,1% (156/354) del hospital y 100% (164) de la microrred. No se detectaron anticuerpos contra HVC en ninguna trabajador, pero 211 (65,9%) trabajadores reconocieron haber tenido al menos un accidente laboral (69,2% en el hospital y 62,8% en la microrred), siendo 182 (56,9%) percutáneos; en 55,3% el líquido contaminante fue la sangre. En conclusión, si bien no encontramos infección por el VHC en el personal de salud, la necesidad de implementar un programa de prevención y manejo de riesgos laborales quedó evidenciada y debería ser tomada en cuenta.

Objectives: To determine CD3+, CD4+, and CD8+ lymphocyte counts, as well as CD4+/CD8+ ratio in chronic carriers of hepatitis B virus (HBV) in an hyperendemic area in Peru (Huanta Province, Ayacucho Department). Materials and methods: This is a comparative study comprising three groups, matched with respect to age (¡Ü20 years old or 20 years old), in an approximate 1:1 ratio. 114 persons were included, who were divided in the following groups: 30 chronic carriers (cases), 44 patients with history of infection (non-carriers or controls), and 40 individuals with no previous contact with HBV (healthy persons). After obtaining an informed consent, two blood samples in a 30- to 45-day period were obtained from each participant, in order to characterize groups and to perform the appropriate studies. Tests performed included: ELISA for HBsAg, anticore for anti-HBc IgM and anti HBc IgG, and cell differentiation technique using flow cytometry for measuring T-lymphocyte subpopulations, CD3+, CD4+, and CD8+. Results: Reduced CD4+ lymphocyte counts per cubic milimeter were found in HBsAG chronic carriers (cases), compared to other groups (p= 0.017); while for CD3+ and CD8+ lymphocytes, as well as for CD4+/CD8+ ratio there were no differences between groups. Also, using analysis of variance (ANOVA), differences were found between the two age groups assessed (p= 0,033), but such differences were not found in the other groups. Conclusions: Lower levels of CD4+ lymphocytes/mm 3 in HBV chronic carriers were found, compared to other groups. It is suggested to perform additional studies on cell-mediated immunity in HBV infection, looking to assess specific cell populations that may be used as potential markers of the outcome of the disease.

Objetivos: Determinar los niveles de linfocitos CD3, CD4, CD8 y coeficiente CD4/CD8 en portadores del virus de la hepatitis B (VHB) de una zona hiperendémica del Perú (Huanta, departamento Ayacucho). Materiales y métodos: Estudio comparativo que incluyó tres grupos, pareados en función a la edad (¡Ü20 ó 20 años) y sexo, a una razón aproximadamente de 1:1. Se incluyeron 114 personas, en los siguientes grupos: 30 portadores crónicos (casos), 44 pacientes con antecedente de infección (no portador o control) y 40 individuos sin contacto previo con el VHB (sanos). De cada individuo, previo consentimiento informado, se obtuvieron dos muestras de sangre en un lapso de 30 a 45 días con la finalidad de caracterizar los grupos y realizar las pruebas de interés. Estas pruebas fueron: ELISA para HBsAg, anticore para anti HBc IgM y anti HBc IgG, y la técnica de diferenciación celular por citometría de flujo para la valoración de subpoblaciones de linfocitos T CD3+, CD4+ y CD8+. Resultados: Se encontró valores disminuidos del número de linfocitos T CD4/mm 3 en los portadores cróni cos de HBsAg (casos), respecto a los otros grupos (p = 0,017); en tanto que para los valores de linfocitos T CD3, T CD8 y coeficiente CD4/CD8 no se encontraron diferencias entre grupos. Asimismo, mediante ANOVA se halló diferencias entre los grupos de edad (mayor y menor de 20 años) de los casos (p = 0,033), característica no observada en los otros grupos. Conclusiones: Se evidenció niveles menores de linfocitos T CD4/mm 3 en l os portadores cróni cos del VHB rel aci ón a l os otros grupos. Se sugiere realizar mayores estudios de inmunidad celular en la infección del VHB, buscando evaluar poblaciones celulares específicas que puedan emplearse como posibles marcadores de la evolución de la enfermedad.