Abstract: Objective: To determine the exposure to aflatoxin B1 (AFB1) in southern Mexico and the presence of the aflatoxin signature mutation in hepatocellular carcinoma (HCC) tissue from patients from a cancer referral center. Materials and methods: We estimated the prevalence and distribution of AFB1 in a representative sample of 100 women and men from Chiapas using the National Health and Nutrition Survey 2018-19. We also examined the presence of the aflatoxin signature mutation in codon 249 (R249S), and other relevant mutations of the TP53 gene in HCC tissue blocks from 24 women and 26 men treated in a national cancer referral center. Results: The prevalence of AFB1 in serum samples was 85.5% (95%CI 72.1-93.1) and the median AFB1 was 0.117 pg/µL (IQR, 0.050-0.350). We detected TP53 R249S in three of the 50 HCCs (6.0%) and observed four other G>T transversions potentially induced by AFB1. Conclusion: Our analysis provides evidence that AFB1 may have a relevant role on HCC etiology in Mexico.

Resumen: Objetivo: Determinar la exposición a aflatoxina_B1 (AFB1) en el sur de México y la presencia de la mutación característica de AFB1 en tejido de carcinoma hepatocelular (CHC) de pacientes de un centro oncológico. Material y métodos: Se estimó la prevalencia y distribución de AFB1 en una muestra representativa de 100 mujeres y hombres de Chiapas a partir de la Encuesta Nacional de Salud y Nutrición 2018-19. También se observó la presencia de la mutación característica de AFB1 en el codón 249 (R249S), y otras mutaciones relevantes del gen TP53 en bloques de tejido de CHC de 24 mujeres y 26 hombres estudiados en un centro de referencia nacional de oncología. Resultados: La prevalencia de AFB1 en las muestras de suero fue de 85.5% (IC95% 72.1-93.1) y la mediana de la concentración 0.117 pg/µL (IQR, 0.050-0.350). Se detectó TP53 R249S en tres de 50 casos de CHC (6.0%) y se observaron cuatro transversiones G>T potencialmente inducidas por AFB1. Conclusión: El presente análisis proporciona evidencia de que la AFB1 puede tener un papel relevante en la etiología del CHC en México.

ABSTRACT Introduction: In global health crises the media is important for reporting on important issues to the population. Objective: To characterize and find associations of perceived fear or exaggeration conveyed by the media in the COVID-19 pandemic. Methods: Analytical and multicenter cross-sectional study. A virtual survey was conducted among 4009 people, in 17 cities of Peru, from March 15-20, 2020. The instrument, previously validated, evaluated three factors: the exaggeration of the media; the fear generated and the communication coming from health personnel, family members and friends. Relationship coefficients and p-values were calculated through the use of generalized linear models, with Gaussian family and identity linkage function. Values of p <0.05 were considered statistically significant. Results: Social networks (64%) and television (57%) were perceived by all participants as exaggerating information; also, television (43%) and social networks (41%) increased the perception of fear. As for their family/friends, they perceived that they exaggerated the situation (39%) and generated fear (25%). In the multivariate analysis, women (p<0.001), those who had completed high school (p=0.023), were university students (p=0.037) and those with a postgraduate degree (p=0.002) had a lower total score of fear and perception of exaggeration. Conclusions: The perception of exaggeration and fear generation in the population were mostly caused by television and social networks.

RESUMEN Introducción: En crisis sanitarias mundiales los medios de comunicación son importantes para informar sobre los temas relevantes a la población. Objetivo: Caracterizar y encontrar asociaciones de la percepción de miedo o exageración que transmiten los medios de comunicación en la pandemia del COVID-19 en ciudades del Perú. Métodos: Estudio transversal analítico y multicéntrico. Se realizó una encuesta virtual a 4009 personas, en 17 ciudades del Perú, del 15-20 de marzo del 2020. El instrumento, previamente validado, evaluó tres factores: la exageración de los medios; el miedo generado y la comunicación que provenía del personal de salud, familiares y amigos. Los coeficientes de relación y los valores p fueron calculados a través del uso de modelos lineales generalizados, con familia Gaussian y función de enlace identity. Se consideraron a los valores de p <0,05 como estadísticamente significativos. Resultados: Los participantes percibieron que las redes sociales (64 %) y la televisión (57 %) exageraban la información; también, los participantes manifestaron que la televisión (43 %) y las redes sociales (41 %) aumentaron la percepción del miedo. En cuanto a su familia/amigos, percibían que exageraban la situación (39 %) y generaban miedo (25 %). Al análisis multivariado, las mujeres (p<0,001), las que tuvieron secundaria completa (p=0,023), las universitarias (p=0,037) y con postgrado (p=0,002) tuvieron un menor puntaje total de miedo y percepción de exageración. Conclusiones: La percepción de exageración y generación de miedo en la población fueron en mayor medida ocasionados por la televisión y las redes sociales.

In this study, we evaluated several techniques for the detection of the yeast form of Cryptococcus in decaying wood and measured the viability of these fungi in environmental samples stored in the laboratory. Samples were collected from a tree known to be positive for Cryptococcus and were each inoculated on 10 Niger seed agar (NSA) plates. The conventional technique (CT) yielded a greater number of positive samples and indicated a higher fungal density [in colony forming units per gram of wood (CFU.g-1)] compared to the humid swab technique (ST). However, the difference in positive and false negative results between the CT-ST was not significant. The threshold of detection for the CT was 0.05.10³ CFU.g-1, while the threshold for the ST was greater than 0.1.10³ CFU-1. No colonies were recovered using the dry swab technique. We also determined the viability of Cryptococcus in wood samples stored for 45 days at 25ºC using the CT and ST and found that samples not only continued to yield a positive response, but also exhibited an increase in CFU.g-1, suggesting that Cryptococcus is able to grow in stored environmental samples. The ST.1, in which samples collected with swabs were immediately plated on NSA medium, was more efficient and less laborious than either the CT or ST and required approximately 10 min to perform; however, additional studies are needed to validate this technique.