Effect of the shear rate and residence time on the lysis of AC16 human cardiomyocyte cells via surface acoustic waves.

The efficient breakage of one cell or a concentration of cells for releasing intracellular material such as DNA, without damaging it, is the first step for several diagnostics or treatment processes. As the cell membrane is easy to bend but resistant to stretching, the exposure of the cell to a shear rate during a short period of time can be sufficient to damage the membrane and facilitate the extraction of DNA. However, how to induce high shear stresses on cells in small microliter volumes samples has remained an elusive problem. Surface acoustic waves operating at high frequencies can induce acoustic streaming leading to shear rates sufficient to cell lysis. Lysis induced by acoustic streaming in sessile droplets has been investigated in the past from the lysis efficiency point of view. However, the effects of the velocity field and shear rate induced by acoustic streaming on the lysis process remain unexplored. Here, we study the lysis of AC16 human cardiomyocytes in microliter droplets under the effect of the shear rate induced by acoustic streaming. It is identified that for a given shear rate, the extracted DNA is also affected by the actuation period which can be attributed to a cycling process that leads to an accumulation of damage on the cell membrane.

In-droplet cell lysis of AC16 human cardiomyocyte cells via surface acoustic waves.

Although several lysis methods are available, biomedical applications are pushing the demand for miniaturised systems and thus for new ways to lyse cells in small volumes. In this work, we demonstrate in-droplet cell lysis of AC16 human cardiomyocyte cells in 20 µL droplets using high frequency surface acoustic waves. The acoustic streaming leads to high shear flow creating porous or breaking the cell membrane and releasing intracellular material. Contrary to previous work where the lysis efficiency is measured by a cell-permeant dye that can be used to determine cell viability, here we propose to quantify the DNA extracted from the cells as a measure of the lysis efficiency. This reagent-free method provides a valuable cell lysis alternative for many biological and biomedical applications, particularly for the development of point-of-care platforms.

Mortalidad en fibrosis quística: análisis retrospectivo de cinco años en institución de alta complejidad: Medellín - Colombia / Cystic fibrosis mortality: retrospective analysis of five years in a highly complex institution: Medellín - Colombia

INTRODUCTION: cystic fibrosis (CF) is a chronic, progressive disease with multisystem involvement and high mortality. An early diagnosis and a multidisciplinary approach lead to longer survival and better quality of life. OBJECTIVE: to characterize the patients who died with CF diagnosis in the period between 2011 and 2017 in the Hospital Universitario San Vicente in Colombia. METHODOLOGY: descriptive study of case series, with retrospective data collection. Results: 168 patients with CF were found in follow-up at the institution during the study period, of which 17 died (10,1%). Eleven deaths corresponded to children under 15 years old (64.7%), with equal distribution of gender (women 52.9% and men 47.1%). The median age at diagnosis was 3 years and median death 12 years. The most frequent clinical compromise was sinopulmonary and gastrointestinal. Pulmonary hypertension occurred in 29.4%. All the patients had a severe functional and nutritional compromise and 82.4% were colonized by Pseudomona aeruginosa. None had multidisciplinary management and most had a low socioeconomic level. BiPAP was used as a palliative measure in 6 patients and all died from ventilatory failure. CONCLUSION: CF mortality in our population continues to present at an early age. The diagnosis of the disease is still made late, compared to developed countries. There was a high proportion of bacterial colonization of the airway and the patients presented a severe clinical and functional status before dying.

INTRODUCCIÓN: la fibrosis quística (FQ) es una enfermedad crónica, progresiva, con compromiso multisistémico y de alta mortalidad. Un diagnóstico temprano y un manejo multidisciplinario llevan a una mayor sobrevida y mejor calidad de vida. OBJETIVO: caracterizar los pacientes que fallecieron con diagnóstico de FQ en el periodo comprendido entre 2011 y 2017 en el Hospital Universitario San Vicente Fundación (HUSVF) de Colombia. METODOLOGÍA: estudio descriptivo de series de casos, con recolección de la información de forma retrospectiva. RESULTADOS: Se encontraron 168 pacientes con FQ en seguimiento en la institución durante el periodo del estudio, de los cuales 17 fallecieron (10.1%). Once muertes correspondieron a menores de 15 años (64.7%), hubo una distribución de género equitativa (mujeres 52.9% y hombres 47.1%). La mediana de edad al momento del diagnóstico fue de 3 años y la de muerte 12 años. El compromiso clínico más frecuente fue sinopulmonar y gastrointestinal. La hipertensión pulmonar se presentó en el 29.4%. Todos los pacientes tenían un grave compromiso funcional, nutricional y el 82,4% estaban colonizados por Pseudomonas aeruginosa. Ninguno tuvo manejo multidisciplinario y la mayoría presentaban un bajo nivel socieconómico. En 6 pacientes se utilizó BiPAP como medida paliativa y todos murieron por falla ventilatoria. CONCLUSIÓN: la mortalidad por FQ en nuestra población se sigue presentando a edades tempranas. El diagnóstico de la enfermedad aún se realiza de forma tardía, comparado con países desarrollados. Hubo alta proporción de colonización bacteriana de la vía aérea y los pacientes presentaron un estado clínico y funcional grave antes de morir.

Tuberculosis and cigarette smoke exposure: An update of in vitro and in vivo studies.

Tuberculosis (TB) has been declared the first cause of death by an infectious agent. Annually, 10.4 million people suffer active TB. Most infected individuals live in low-income countries, where social and economic conditions enhance the dissemination and progression of the disease. These countries have a high percentage of smokers. Thousands of studies have linked cigarette smoke (CS) with increased risk of many diseases, such as cancer and lung diseases. Numerous in vitro studies have been conducted to evaluate the general and specific toxic effects of CS in lung immune function. Smoke exposure increases the risk of TB development three-fold. However, until now, only few animal studies have been performed to analyze the association between smoke and TB. In the present work, we review in vitro and in vivo studies whose aim was to analyze the molecular basis of TB susceptibility caused by exposure to CS.

Factores de riesgo asociados a la sífilis congénita en tres instituciones desalud de Sincelejo (Colombia) / Risk factors associated with congenital syphilis in three health institutions in

Objetivo: Se Identificaron los factores de riesgo para sífilis congénita, relacionados con los antecedentes deinfecciones de transmisión sexual, las prácticas sexuales de la madre y su pareja, la asistencia al control prenatal,tratamiento para sífilis y vía del parto, en un grupo de puérperas, registradas en la IPS San Luis, las Américas y elHospital Universitario de Sincelejo entre los años 2007 a 2010. Metodología: Se desarrollo un estudio descriptivo y de corte con una selección muestral intencional de 34 madres cuyos hijos tuvieron pruebas de VDRL y FTA - abspositivos, que residían en Sincelejo y que fue posible su ubicación, quienes firmaron el consentimiento informado. Se aplicó un instrumento dirigido a la madre del niño con sífilis congénita, que fue tabulado en una base de SPSS 15.0.Resultados: Se encontró que la mayoría de las madres eran de estrato uno y dos, que no alcanzaron un nivel de educación media; 68,0% tenía entre 16 y 24 años de edad, 55,8% de los compañeros sexuales no se hizo la prueba para el diagnostico de Sífilis y 88,2% no usó preservativo antes ni durante el tratamiento. Conclusiones: La inasistencia o la asistencia irregular a las consultas prenatales y la poca adherencia a las medidas de protección sexual por parte de la pareja, fueron aspectos que interfirieron con un tratamiento eficaz de las gestantes. Los contactos de las madres infectadas y tratadas no están siendo diagnosticados en un alto porcentaje, lo que refleja una falla en el seguimiento a los contactos de las gestantes para evitar la reinfección.

Objectives: To identify risk factors for congenital syphilis associated with a history of sexually transmitted infections, sexual practices of the mother and her partner, attendance for prenatal care, treatment for syphilis and type of delivery, in a group of postpartum women, registered in San Luis, Las Americas IPS's and the Hospital Universitario de Sincelejo from 2007 to 2010. Methodology: We developed a descriptive and cross-sectional study with an intentional selection of 34 mothers whose children had VDRL and FTA-ABS positive, residing in Sincelejo and were possible to locate, that signed the informed consent. An instrument is directed to the mother of the child with congenital syphilis, which was tabulated on a foundation of SPSS 15.0. Results: We found that most mothers were in strata one and two, that did not reach the middle school level; 68,0% were between 16 and 24 years old, 55.8% of sexual partners did not test for the diagnosis of syphilis and 88.2% did not use condoms before or during the treatment. Conclusions: The absence or irregular attendance at the prenatal care program and poor adherence to protective measures of sexual partners, are issues that interfere with effective treatment for pregnant women. Thecontacts of the infected and treated mothers are not being diagnosed in a large percentage, reflecting a failure in the following up of the contact of pregnant women to avoid re-infection.