Flagellar Motility of Trypanosoma cruzi Epimastigotes

The hemoflagellate Trypanosoma cruzi is the causative agent of American trypanosomiasis. Despite the importance of motility in the parasite life cycle, little is known about T. cruzi motility, and there is no quantitative description of its flagellar beating. Using video microscopy and quantitative vectorial analysis of epimastigote trajectories, we find a forward parasite motility defined by tip-to-base symmetrical flagellar beats. This motion is occasionally interrupted by base-to-tip highly asymmetric beats, which represent the ciliary beat of trypanosomatid flagella. The switch between flagellar and ciliary beating facilitates the parasite's reorientation, which produces a large variability of movement and trajectories that results in different distance ranges traveled by the cells. An analysis of the distance, speed, and rotational angle indicates that epimastigote movement is not completely random, and the phenomenon is highly dependent on the parasite behavior and is characterized by directed and tumbling parasite motion as well as their combination, resulting in the alternation of rectilinear and intricate motility paths

Improved Method for In Vitro Secondary Amastigogenesis of Trypanosoma cruzi: Morphometrical and Molecular Analysis of Intermediate Developmental Forms

Trypanosoma cruzi undergoes a biphasic life cycle that consists of four alternate developmental stages. In vitro conditions to obtain a synchronic transformation and efficient rates of pure intermediate forms (IFs), which are indispensable for further biochemical, biological, and molecular studies, have not been reported. In the present study, we established an improved method to obtain IFs from secondary amastigogenesis. During the transformation kinetics, we observed progressive decreases in the size of the parasite body, undulating membrane and flagellum that were concomitant with nucleus remodeling and kinetoplast displacement. In addition, a gradual reduction in parasite movement and acquisition of the amastigote-specific Ssp4 antigen were observed. Therefore, our results showed that the in vitro conditions used obtained large quantities of highly synchronous and pure IFs that were clearly distinguished by morphometrical and molecular analyses. Obtaining these IFs represents the first step towards an understanding of the molecular mechanisms involved in amastigogenesis

Regulatory elements involved in the post-transcriptional control of stage-specific gene expression in Trypanosoma cruzi: a review

Trypanosoma cruzi, a protozoan parasite that causes Chagas disease, exhibits unique mechanisms for gene expression such as constitutive polycistronic transcription of protein-coding genes, RNA editing and trans-splicing. In the absence of mechanism controlling transcription initiation, organized subsets of T. cruzi genes must be post-transcriptionally co-regulated in response to extracellular signals. The mechanisms that regulate stage-specific gene expression in this parasite have become much clearer through sequencing its whole genome as well as performing various proteomic and microarray analyses, which have demonstrated that at least half of the T. cruzi genes are differentially regulated during its life cycle. In this review, we attempt to highlight the recent advances in characterising cis and trans-acting elements in the T. cruzi genome that are involved in its post-transcriptional regulatory machinery

Protocolo de manejo en deshidratación hipernatrémica neonatal

La deshidratación hipernatrémica neonatal (DHN) es una enfermedad grave y se asocia con edema cerebral, hemorragia intracraneal y gangrena. El manejo de estos pacientes es controvertido por las complicaciones que se han reportado si la corrección de la natremia se lleva a cabo rápidamente. Se propone un protocolo para disminuir lentamente el sodio sérico. Metodología: Estudio prospectivo que incluyó a pacientes con Na sérico >150 mEq. Se manejaron con una carga rápida de solución salina y soluciones de rehidratación con 50 mEq de Na/L y glucosa al 5%. Se monitorizó el Na sérico a las 12 y las 24 horas. Resultados: Se ingresaron al estudio 51 pacientes, con una incidencia identificada de 10.2 casos por 1,000 recién nacidos vivos. El promedio de Na en el momento del ingreso fue de 158 mEq/l. El promedio de disminución de Na en las primeras 12 horas fue de 0.53 ± 0.08 mEq/l/h. En las siguientes 12 horas fue de 0.46 ± 0.09 mEq/l/h. No se presentaron alteraciones neurológicas en ningún paciente. Conclusiones: La rehidratación en el neonato con DHN con una o dos cargas de solución salina al 0.9% y el posterior manejo con soluciones con 50 mEq/l de Na y solución glucosada al 5% (“tercio normal”) fueron seguros para descender lentamente los niveles séricos de Na, aproximadamente, a 0.5 mEq/h

Impact of COVID-19 Pandemic on Cutaneous Squamous Cell Carcinoma: A Single-Centre Study of Epidemiologic, Clinic and Histopathological Factors

Background: The COVID-19 pandemic may have adversely affected the early diagnosis of skin cancer. Objective: To compare epidemiological, clinical and histopathological characteristics in patients undergoing cutaneous squamous cell carcinoma (SCC) surgery before and after the beginning of the pandemic. Material & methods: We conducted a cross-sectional study including two case series: (1) patients operated on for SCC in the year after the first state of alarm in Spain (15 March 2020), and (2) patients with SCC operated on in the previous year. Epidemiological, clinical and histopathological variables, tumour stage and risk grade were collected. Results: 248 patients were included (127 undergoing surgery before the pandemic and 121 after the pandemic). After the beginning of the pandemic, the percentage of high-risk SCC significantly increased from 35.3% to 46.2% (p = 0.011). However, no significant differences were found in thickness, perineural invasion or metastases. Conclusions: Although there has not been a significant reduction in the number of SCC operated on after the pandemic, there has been a significant increase in high-risk SCC. All this could lead to an increase in skin cancer mortality in the future. Resumen: Antecedentes: La pandemia de COVID-19 ha podido afectar negativamente el diagnóstico precoz del cáncer de piel. Objetivo: Comparar las características epidemiológicas, clínicas e histopatológicas en los pacientes intervenidos de carcinoma de células escamosas (CCE) cutáneo antes de la pandemia y después del inicio de la pandemia. Material y métodos: Se diseñó un estudio transversal que incluía 2 series de pacientes: 1) pacientes intervenidos de CCE el año posterior a la declaración del confinamiento general en España (15 de marzo de 2020), y 2) pacientes intervenidos de CCE el año previo. Se recogieron variables epidemiológicas, clínicas e histopatológicas, así como el estadio tumoral y el grado de riesgo. Resultados: Se incluyeron 248 pacientes (127 intervenidos antes de la pandemia y 121 intervenidos después de la pandemia). Tras el inicio de la pandemia, el porcentaje de CCE de alto riesgo aumentó significativamente de 32,3 a 45,5% (p = 0,011). No obstante, no se encontraron diferencias significativas en el grosor tumoral, la invasión perineural o la presencia de metástasis. Conclusiones: Aunque no se produjo una reducción significativa en el número de CCE intervenidos después de la pandemia, ha habido un incremento significativo en los CCE de alto riesgo. Todo ello puede conllevar un incremento en la mortalidad por cáncer de piel en el futuro

[Artículo traducido] Impacto de la pandemia COVID-19 en el carcinoma de células escamosas cutáneo: un estudio unicéntrico de los factores epidemiológicos, clínicos e histopatológicos

Resumen: Antecedentes: La pandemia de COVID-19 ha podido afectar negativamente el diagnóstico precoz del cáncer de piel. Objetivo: Comparar las características epidemiológicas, clínicas e histopatológicas en los pacientes intervenidos de carcinoma de células escamosas (CCE) cutáneo antes de la pandemia y después del inicio de la pandemia. Material y métodos: Se diseñó un estudio transversal que incluía 2 series de pacientes: 1) pacientes intervenidos de CCE el año posterior a la declaración del confinamiento general en España (15 de marzo de 2020), y 2) pacientes intervenidos de CCE el año previo. Se recogieron variables epidemiológicas, clínicas e histopatológicas, así como el estadio tumoral y el grado de riesgo. Resultados: Se incluyeron 248 pacientes (127 intervenidos antes de la pandemia y 121 intervenidos después de la pandemia). Tras el inicio de la pandemia, el porcentaje de CCE de alto riesgo aumentó significativamente de 32,3 a 45,5% (p = 0,011). No obstante, no se encontraron diferencias significativas en el grosor tumoral, la invasión perineural o la presencia de metástasis. Conclusiones: Aunque no se produjo una reducción significativa en el número de CCE intervenidos después de la pandemia, ha habido un incremento significativo en los CCE de alto riesgo. Todo ello puede conllevar un incremento en la mortalidad por cáncer de piel en el futuro. Abstract: Background: The COVID-19 pandemic may have adversely affected the early diagnosis of skin cancer. Objective: To compare epidemiological, clinical and histopathological characteristics in patients undergoing cutaneous squamous cell carcinoma (SCC) surgery before and after the beginning of the pandemic. Material & methods: We conducted a cross-sectional study including two case series: (1) patients operated on for SCC in the year after the first state of alarm in Spain (15 March 2020), and (2) patients with SCC operated on in the previous year. Epidemiological, clinical and histopathological variables, tumour stage and risk grade were collected. Results: 248 patients were included (127 undergoing surgery before the pandemic and 121 after the pandemic). After the beginning of the pandemic, the percentage of high-risk SCC significantly increased from 35.3% to 46.2% (p = 0.011). However, no significant differences were found in thickness, perineural invasion or metastases. Conclusions: Although there has not been a significant reduction in the number of SCC operated on after the pandemic, there has been a significant increase in high-risk SCC. All this could lead to an increase in skin cancer mortality in the future

The mKate fluorescent protein expressed by Leishmania mexicana modifies the parasite immunopathogenicity in BALB/c mice.

Parasites have been engineered to express fluorescent reporter proteins, yet the impact of red fluorescent proteins on Leishmania infections remains largely unknown. We analysed the infection outcome of Leishmania mexicana parasites engineered for the constitutive expression of mKate protein and evaluated their immunogenicity in BALB/c mice. Infection of BALB/c mice with mKate transfected L. mexicana (Lmex <sup>mKate</sup> ) parasites caused enlarged lesion sizes, leading to ulceration, and containing more parasites, as compared to Lmex <sup>WT</sup> . The mKate protein showed immunogenic properties inducing antibody production against the mKate protein, as well as enhancing antibody production against the parasite. The augmented lesion sizes and ulcers, together with the more elevated antibody production, were related to an enhanced number of TNF-α and IL-1β producing cells in the infected tissues. We conclude that mKate red fluorescent protein is an immunogenic protein, capable of modifying disease evolution of L. mexicana