Resumen La memoria semántica (SM) es un tipo de memoria a largo plazo asociada con el almacenamiento de información general sobre el mundo. Aquí evaluamos las características de la batería SM, desarrollada por Catricalà et al. (2013), en una muestra de niños colombianos. Esta batería fue concebida originalmente para evaluar adultos, y presenta seis subpruebas que evalúan SM en diferentes modalidades, utilizando un conjunto común de 48 estímulos en las categorías de vida y no vida. El diseño del presente estudio es de tipo transversal y exploratorio. La muestra estaba compuesta por 111 niños, 57 niños (51%) y 54 niñas (49%), que tenían 6 (n = 68) y 7 (n = 43 ) años y no tenían discapacidad intelectual. Se utilizaron modelos de regresión lineal robustos y redes de correlación. Encontramos un efecto de la edad en la inteligencia general después de corregir por género, y no hubo diferencias en las seis puntuaciones de la subprueba después de realizar correcciones por género y edad. Además, se encontró que la edad se asociaba positivamente con el nombramiento de fotografías en color (β = .75, p = .039), nombrando en respuesta a una descripción oral (β = 1.81, p = .039), clasificación de imágenes en cuatro niveles (β = 7.22, p = .029) y verificación de oraciones (β = 26.66, p = .01). Además, hubo diferencias entre los resultados obtenidos en adultos en el estudio original y en los niños de nuestro estudio. Este estudio exploratorio respalda la viabilidad de la traducción al español de Catricalà et al. (2013) batería para evaluar SM en niños con una condición no clínica. Se necesitan estudios futuros para evaluar las propiedades psicométricas de esta batería SM, y para corroborar y expandir nuestros hallazgos en una muestra más grande de niños control, y en niños con algún grado de discapacidad intelectual o que padecen algunas condiciones neurodegenerativas o psiquiátricas.

Abstract. Semantic memory (SM) is a type of long-term memory associated with the storage of general information about the world. Here we assessed the characteristics of the SM battery, developed by Catricalà et al. (2013), in a sample of Colombian children. This battery was originally conceived to evaluate adults, and features six subtests that assess SM in different modalities, using a common set of 48 stimuli in both living and nonliving categories. The design of the current study is of a cross-sectional and exploratory type. The sample was composed of 111 children, 57 boys (51%) and 54 girls (49%), who were 6 (n = 68) and 7 (n = 43) years old and had no intellectual disability. Robust linear regression models and correlation networks were used. We found an effect of age on general intelligence after correcting for gender, and no differences on the six subtest scores after corrections for gender and age were performed. Furthermore, age was found to be positively associated with the naming of colored photographs (β = .75, p = .039), naming in response to an oral description (β = 1.81, p = .039), picture sorting at four levels (β = 7.22, p = .029), and sentence verification (β = 26.66, p = .01). In addition, there were differences between the results obtained in adults in the original study and in the children of our study. This exploratory study supports the feasibility of the Spanish translation of the Catricalà et al. (2013) battery to assess SM in children with a nonclinical condition. Future studies are needed to evaluate the psychometric properties of this SM battery, and to corroborate and expand our findings in a larger sample of control children, and in children with some degree of intellectual disability or suffering of some neurodegenerative or psychiatric conditions.

Objetivo: demostrar que la exposición al humo, producto de la electrocoagulación, origina cambios en la mucosa nasal en médicos en formación de un hospital público en México. Metodología: se realizó un estudio de cohorte fija prospectivo, cuyo universo de trabajo estuvo conformado por un total de 43 médicos, 20 corresponden a médicos de especialidades no quirúrgicas (no expuestos a la inhalación de humo del cauterio) y 23 médicos de especialidades quirúrgicas (expuestos a la inhalación de humo del cauterio), a quienes se les realizó una biopsia nasal al inicio y otra al finalizar los 4 años de su formación como especialistas. Las biopsias fueron revisadas por el Jefe de Patología del hospital, se calculó incidencia de cambios en la mucosa nasal, en los grupos expuesto y no expuesto, índice de exposición y riesgo relativo. Resultados: el total de los médicos especialistas en formación incluidos en el estudio, presentaron biopsia sin daños en la mucosa nasal al inicio del estudio; mismos que al término de sus 4 años de especialidad presentaron lo siguiente: el 70% de los médicos residentes expuestos tuvieron algún cambio histopatológico en la mucosa nasal (hiperplasia o metaplasia escamosa), mientras que solo el 5% (1/20) de los no expuestos lo presentó; el factor de riesgo de presentar daño a la mucosa nasal por la exposición en estudio se calculó en 13,8. Las lesiones más frecuentes por la exposición al humo producido por la electrocoagulación fueron la hiperplasia y la metaplasia escamosa. Conclusiones: nuestros resultados demuestras que los residentes expuestos al humo producido por la electrocoagulación presentan cambios en la mucosa nasal.

Objective: to prove that exposure to smoke resulting from electrocoagulation causes changes in the nasal mucosa of physicians in training at a public hospital in Mexico. Methodology: a prospective fixed cohort study was conducted with a working universe consisting of 43 physicians distributed as follows: a group of 20 professionals with non-surgical specialties (thus unexposed to electrocautery smoke inhalation), and another group of 23 with surgical specialties (thus they were exposed to electrocautery smoke inhalation). They underwent two nasal biopsies: one at the beginning of the study and another after training as specialists for four years. The biopsies were reviewed by the hospital´s chief of Pathology and the incidence of changes in the nasal mucosa in both groups was calculated together with exposure index and the relative risk. Results: the biopsies performed at baseline showed that none of the specialists in training included in this study had damages in the nasal mucosa. The final biopsies, performed after the four-year medical training, had the following results: 70% of the medical residents, who were exposed, showed some histopathological changes in the nasal mucosa (hyperplasia or squamous metaplasia), whereas only 5% (1/20) of the unexposed individuals had them; the risk factor for nasal mucosa damage by exposure was estimated at 13.8. The most common lesions resulting from exposure to smoke from electrocoagulation were hyperplasia and squamous metaplasia. Conclusions: our results demonstrate that residents exposed to smoke produced by electrocoagulation have changes in the nasal mucosa.

Objetivo: Demonstrar que a exposição à fumaça produzida pela electrocoagulação gera mudanças na mucosa nasal de médicos estudantes de um hospital público do México. Metodologia: Realizou-se um estudo prospectivo de coorte fixa, com um universo de trabalho de 43 médicos. 20 médicos de especialidades não cirúrgicas (não expostos à fumaça do cautério), e 23 médicos de especialidades cirúrgicas (expostos à fumaça do cautério). Realizou-se uma biopsia nasal no início e outra no final, após 4 anos da sua formação como especialistas. As biopsias foram realizadas pelo chefe de Patologia do hospital e os resultados foram processados com o programa Social Sciences (SPSS Statistics), versão 18. Foi possível avaliar a incidência das mudanças na mucosa nasal dos grupos expostos e dos grupos não expostos, também se calculou o índice de exposição e o risco relativo. Resultados : Nenhum dos médicos especialistas em formação incluídos no estudo tinha danos na sua mucosa nasal, segundo a biopsia feita no início do estudo. Depois de 4 anos na especialização: 70% dos médicos residentes expostos teve alguma mudança histopatológica na mucosa nasal (hiperplasia o metaplasia escamosa), enquanto que somente 5% (1/20) dos não expostos apresentou mudança. O fator de risco do dano na mucosa nasal pela exposição estudada se calculou em 13,8. Os prejuízos mais frequentes pela exposição à fumaça produzida pela electrocoagulação foram a hiperplasia e a metaplasia escamosa. Conclusão: Nossos resultados demonstram que os residentes expostos à fumaça produzida pela electrocoagulação apresentam mudanças na sua mucosa nasal.

La metaciclogénesis de Trypanosoma cruzi es la transformación del estadio epimastigota en tripomastigota metacíciclico que ocurre en la ampolla rectal del insecto vector. Durante este proceso se ha implicado una activación del metabolismo proteico, con probable participación de proteasas en la degradación de proteínas del parásito. En el presente trabajo se determinó el efecto de las condiciones de mantenimiento de T. cruzi en el laboratorio sobre la actividad de proteasas y su relación sobre la metaciclogénesis espontánea en cultivos axénicos. Se trabajó con el clon Dm30L de Trypanosoma cruzi mantenido en el laboratorio mediante pases trimestrales chipo-ratón (condición triatomino: CT) o repiques semanales durante 15 años en medio LITB (condición cultivo: CC). En ambas condiciones, se hizo curva de crecimiento durante 30 días en medio LITB suplementado con 10, 24 y 48 mM glucosa, calculándose el porcentaje de metacíclicos espontáneos y determinación de la actividad de proteasas. En 10 mM glucosa, parásitos de la CT presentaron mayor expresión de proteasas y porcentaje de metacíclicos respecto a la CC. En la CT, el crecimiento en 48 mM glucosa redujo las variables antes mencionadas, mientras que no se evidenció actividad proteolítica ni metaciclogénesis espontánea en parásitos de la CC en altas concentraciones de glucosa. En todos los casos se evidenció mayor actividad de cisteín proteasas durante la fase estacionaria del cultivo. No se reportó actividades metaloproteasas en ninguna de las condiciones estudiadas, pero sí en el clon Dm28c utilizado como control de la expresión de este tipo de enzima. Estos resultados sugieren que la expresión de proteasas está influenciada por la constitución genética del parásito y que la CC provoca disminución de la actividad proteolítica que persisten aún en condiciones de agotamiento de carbohidratos del medio, con una concomitante reducción significativa en el porcentaje de metacíclicos espontáneos.

Trypanosoma cruzi metacyclogenesis is the transformation of epimastigote stage to trypomastigote metacyclic that happens in the rectal ampulla of the insect vector. During this process it has been implicated protein metabolism activation, with proteases likely involvement in parasite protein degradation. In this study we determined the effect of T. cruzi keeping conditions in the laboratory on the activity of proteases and their relationship on spontaneous metacyclogenesis in axenic culture. We worked with Trypanosoma cruzi Dm30L clone maintained in the laboratory by quarterly passes triatomine-mouse (triatomine condition: TC) or serial culture media during 15 years in LITB medium (culture condition: CC). In both conditions, growth curve was made for 30 days in LITB medium supplemented with 10, 24 and 48 mM glucose, calculating the percentage of spontaneous metacyclics and determining proteases activity. In 10 mM glucose, TC parasites showed higher expression of proteases and metacyclic percentage relative to the CC. In TC, the growth in 48 mM glucose reduced the above variables, while no evidenced proteolytic activity nor spontaneous metacyclogenesis on CC parasites in high glucose concentrations. In all cases there was greater cysteine proteases activity during the stationary phase of the culture. Metalloprotease activity was not reported in any of the conditions studied, but it was detected in clone Dm28c used as control of expression of this type of enzyme. These results suggest that the expression of proteases is influenced by the genetic makeup of the parasite and the CC causes decrease of proteolytic activity which persists even in carbohydrate depleted conditions of the medium, with a concomitant significant reduction in the percentage of spontaneous metacyclics.

Amastigogenesis occurs first when metacyclic trypomastigotes from triatomine urine differentiate into amastigotes inside mammalian host cells and a secondary process when tissue-derived trypomastigotes invade new cells and differentiate newly to amastigotes. Using scanning electron microscopy, we compared the morphological patterns manifested by trypomastigotes and metacyclic forms of Trypanosoma cruzi during their axenic-transformation to amastigotes in acidic medium at 37°C. We show here that in culture MEMTAU medium, secondary and primary axenic amastigogenesis display different morphologies. As already described, we also observed a high differentiation rate of trypomastigotes into amastigotes. Conversely, the transformation rate of in vitro-induced-metacyclic trypomastigotes to amastigotes was significantly slower and displayed distinct patterns of transformation that seem environment-dependent. Morphological comparisons of extracelullar and intracellular amastigotes showed marked similarities, albeit some differences were also detected. SDS-PAGE analyses of protein and glycoprotein from primary and axenic extracelullar amastigotes showed similarities in glycopeptide profiles, but variations between their proteins demonstrated differences in their respective macromolecular constitutions. The data indicate that primary and axenic secondary amastigogenesis of T. cruzi may be the result of different developmental processes and suggest that the respective intracellular mechanisms driving amastigogenesis may not be the same.

Attempts to recreate all the developmental stages of Trypanosoma cruzi in vitro have thus far been met with partial success. It is possible, for instance, to produce trypomastigotes in tissue culture and to obtain metacyclic trypomastigotes in axenic conditions. Even though T. cruzi amastigotes are known to differentiate from trypomastigotes and metacyclic trypomastigotes, it has only been possible to generate amastigotes in vitro from the tissue-culture-derived trypomastigotes. The factors and culture conditions required to trigger the transformation of metacyclic trypomastigotes into amastigotes are as yet undetermined. We show here that pre-incubation of metacyclic trypomastigotes in culture (MEMTAU) medium at 37°C for 48 h is sufficient to commit the parasites to the transformation process. After 72 h of incubation in fresh MEMTAU medium, 90% of the metacyclic parasites differentiate into forms that are morphologically indistinguishable from normal amastigotes. SDS-PAGE, Western blot and PAABS analyses indicate that the transformation of axenic metacyclic trypomastigotes to amastigotes is associated with protein, glycoprotein and antigenic modifications. These data suggest that (a) T. cruzi amastigotes can be obtained axenically in large amounts from metacyclic trypomastigotes, and (b) the amastigotes thus obtained are morphological, biological and antigenically similar to intracellular amastigotes. Consequently, this experimental system may facilitate a direct, in vitro assessment of the mechanisms that enable T. cruzi metacyclic trypomastigotes to transform into amastigotes in the cells of mammalian hosts.

The amastigogenesis primary of T. cruzi occurs naturally when metacyclic trypomastigotes transform into amastigotes within the cells of the mammalian host. The in vitro study of the macromolecular changes that occur over several days during the transformation process should provide significant indications of how the parasite adapts to the mammalian host environment. We show here that metacyclic trypomastigotes pre-incubated at 37° C in a protein-rich medium reach a high degree of transformation to amastigotes when re-incubated in the fresh medium. Giemsa-stained smears show that during the pre-incubation phase, the metacyclic trypomastigotes undergo lengthening at the posterior end and a thinning out of the entire body. SDS-PAGE analysis of polypeptides and glycopeptides or Western blot with stage-specific antisera analyses indicate that the in vitro primary amastigogenesis is associated with abrupt changes in protein, glycoprotein, and stage-specific antigens that occur simultaneously during the first 24 hours of pre-incubation. Since the differentiating system consists of a rich media at 37° C, temperature and medium constitution must trigger a macromolecular differentiation to amastigotes that precedes the morphological transformation by several days. This transformation is associated with the rearrangement of stage-specific antigens and takes place when the culture medium is changed.