Noninvasive and Continuous Monitoring of On-Chip Stem Cell Osteogenesis Using a Reusable Electrochemical Immunobiosensor.

Noninvasive monitoring of biofabricated tissues during the biomanufacturing process is needed to obtain reproducible, healthy, and functional tissues. Measuring the levels of biomarkers secreted from tissues is a promising strategy to understand the status of tissues during biofabrication. Continuous and real-time information from cultivated tissues enables users to achieve scalable manufacturing. Label-free biosensors are promising candidates for detecting cell secretomes since they can be noninvasive and do not require labor-intensive processes such as cell lysing. Moreover, most conventional monitoring techniques are single-use, conducted at the end of the fabrication process, and, challengingly, are not permissive to in-line and continual detection. To address these challenges, we developed a noninvasive and continual monitoring platform to evaluate the status of cells during the biofabrication process, with a particular focus on monitoring the transient processes that stem cells go through during in vitro differentiation over extended periods. We designed and evaluated a reusable electrochemical immunosensor with the capacity for detecting trace amounts of secreted osteogenic markers, such as osteopontin (OPN). The sensor has a low limit of detection (LOD), high sensitivity, and outstanding selectivity in complex biological media. We used this OPN immunosensor to continuously monitor on-chip osteogenesis of human mesenchymal stem cells (hMSCs) cultured 2D and 3D hydrogel constructs inside a microfluidic bioreactor for more than a month and were able to observe changing levels of OPN secretion during culture. The proposed platform can potentially be adopted for monitoring a variety of biological applications and further developed into a fully automated system for applications in advanced cellular biomanufacturing.

Care of patients on home parenteral nutrition during the first year of the COVID-19 pandemic: Management of central line-associated bloodstream infections.

BACKGROUND AND AIM: The aim of this study was to analyze central line-associated bloodstream infections (CLABSI) in home parenteral nutrition (HPN) patients assisted by an interdisciplinary team during the first year of the COVID-19 pandemic in Argentina. METHODS: Longitudinal, retrospective and analytical study of patients on HPN for ≥90 days during 2020. Data collection included age (adults >18 years, pediatric ≤18 years), gender, diagnosis, type of catheter, number of lumens, venous access, days on HPN, infusion modality and number of CLABSI-associated events. In COVID-19 cases, number of patients, disease progression, mortality rate and microorganisms involved were analyzed. RESULTS: A total of 380 patients were included, 120 (31.6%) pediatric and 260 (68.4%) adult patients. Median age was 44.50 years (10; 62.25). Twelve patients (3.15% of the total) had COVID-19; of these, two pediatric and seven adult patients had no complications, and three adults died of COVID-19 pneumonia. The diagnoses observed were benign chronic intestinal failure (CIF, n = 311), grouped into short bowel (n = 214, 56.3%), intestinal dysmotility (n = 56, 14.7%), intestinal fistula (n = 20, 5.3%), and extensive small bowel mucosal disease (n = 21, 5.5%); malignant tumors (n = 52, 13.7%); other (n = 17, 4.4%). Total catheter days were 103,702. Median days of PN duration per patient were 366 (176.2, 366). The types of catheters used were tunneled (317 patients, 83.4%); peripherally inserted central (PICC) line (55 patients, 14.5%) and ports (8 patients; 2.1%). A total of 111 CLABSI was registered, with a prevalence of 1.09/1000 catheter days (adult, 0.86/1000 days; pediatric, 1.51/1000 days). The microorganisms identified in infectious events were Gram + bacteria (38, 34.5%); Gram-bacteria (36, 32%); mycotic (10, 9%); polymicrobial (4, 3.6%); negative culture and signs/symptoms of CLABSI (23, 20.3%). The odds ratio between pediatric and adult patients was 2.29 (1.35, 3.90). CONCLUSION: The rate of CLABSI during the COVID-19 pandemic was within the ranges reported by international scientific societies. The risk of CLABSI was higher in pediatric patients, and mortality rate in COVID-19 infected patients was higher than in the general population.

Tunable and Compartmentalized Multimaterial Bioprinting for Complex Living Tissue Constructs.

Recapitulating inherent heterogeneity and complex microarchitectures within confined print volumes for developing implantable constructs that could maintain their structure in vivo has remained challenging. Here, we present a combinational multimaterial and embedded bioprinting approach to fabricate complex tissue constructs that can be implanted postprinting and retain their three-dimensional (3D) shape in vivo. The microfluidics-based single nozzle printhead with computer-controlled pneumatic pressure valves enables laminar flow-based voxelation of up to seven individual bioinks with rapid switching between various bioinks that can solve alignment issues generated during switching multiple nozzles. To improve the spatial organization of various bioinks, printing fidelity with the z-direction, and printing speed, self-healing and biodegradable colloidal gels as support baths are introduced to build complex geometries. Furthermore, the colloidal gels provide suitable microenvironments like native extracellular matrices (ECMs) for achieving cell growths and fast host cell invasion via interconnected microporous networks in vitro and in vivo. Multicompartment microfibers (i.e., solid, core-shell, or donut shape), composed of two different bioink fractions with various lengths or their intravolume space filled by two, four, and six bioink fractions, are successfully printed in the ECM-like support bath. We also print various acellular complex geometries such as pyramids, spirals, and perfusable branched/linear vessels. Successful fabrication of vascularized liver and skeletal muscle tissue constructs show albumin secretion and bundled muscle mimic fibers, respectively. The interconnected microporous networks of colloidal gels result in maintaining printed complex geometries while enabling rapid cell infiltration, in vivo.

Evaluación de los aprendizajes en ciencias morfológicas: Anatomía Humana, embriología y genética e histología / Evaluation of learning in morphological science: Human Anatomy, embryology and genetics and histology

Este trabajo es el resultado de experiencias e investigaciones efectuadas en el campo del proceso de la evaluación de aprendizaje en las asignaturas morfológicas de Anatomía Humana, Embriología y Genética e Histología de la carrera de medicina de la Universidad Mayor de San Simón, realizando una crítica al modelo de evaluación tradicional basado, sobre todo, en la medición de los contenidos declarativos.La propuesta del trabajo es sistematizar una evaluación alternativa, integral y tridimensional donde el docente formula objetivos, indicadores de aprendizaje y evalúa en función de estos criterios aplicando instrumentos pertinentes a las diferentes áreas, no solamente conceptuales sino también procedimentales y actutidinales, utilizando los distintos instrumentos y momentos de evaluación donde se evaluará a cada estudiante en función de su desempeño y no en relación a los logros de sus compañeros, priorizando las autoevaluaciones y las coevaluaciones. Con este objetivo se plantea, sobre la base de un aprendizaje significativo, sistematizar las evaluaciones integrales, dinámicas y continuas en las materias morfológicas de la carrera de medicina, proponiendo, en base a una sistematización de las experiencias de aprendizaje, modelos operativos de evaluación de los aprendizajes en las tres asignaturas de las ciencias morfológicas.

La coloración fluorescente con naranja de acridina y el PAP: validación de ambas técnicas para la detección de trichomonas vaginalis / Fluorescent staining with acridine orange and PAP smear: validation tests of both tecniques for the detection of trichomonas vaginalis

Se efectuó la validación de la colorización de Papanicolaou, utilizada para citología vaginal, frente a la colorización fluorescente con naranja de acridina, a fin de evaluar el valor de un resultado negativo para Trichomonas vaginalis obtenido en un PAP. Se estudiaron 80 muestras de flujo vaginal de mujer entre 18 y 45 años, pacientes de consultorios externos de Ginecología del Hospital Municipal de la ciudad de Bahía Blanca, Provincia de Buenos Aires (Argentina). Las muestras se colorearon paralelamente por la técnica de Papanicolaou y por la coloración fluorescente con naranja de acridina. Los resultados mostraron que el PAP presenta una sencibilidad del 54,5 por ciento para la detección de T. vaginalis, validación efectuada frente a la coloración fluorescente con naranja de acridina, para una prevalencia de enfermedad en el grupo de mujeres estudiadas del 13,75 por ciento y un nivel de confianza del 95 por ciento. Para ensayos "en paralelo" con ambas coloraciones, el valor global de la prueba fue del 93,8 por ciento, con un valor predictivo del resultado negativo del 93,2 por ciento. Concluimos que si bien T. vaginalis es detectada en el PAP, éste no presenta sencibilidad significativamente elevada como para ser considerada como única prueba, debiéndose complementar siempre con una coloración fluorescente con naranja acridina, u otra prueba de similar valor

Algunas consideraciones sobre el examen en fresco en el diagnóstico de trichomonas vaginalis / Some considerations about the wet mount technique in the trichomonas vaginalis diagnosis

Para evaluar la importancia de la inmediata observación del examen en fresco entre porta y cubreobjetos del flujo vaginal, para la investigación de Trichomonas vaginalis, se procesaron 500 muestras en dos grupos de mujeres que concurían para ser estudiadas en dos centros asistenciales de la ciudad de Bahía Blanca (Argentina), 250 pacientes en cada lugar. En el Centro "A" las muestras se procesaron inmediatamente, mientras que en el "B" la observación en fresco entre porta y cubreobjetos al microscopio óptico se realizó luego de transcurrida una hora y media y antes de las dos horas luego de la extracción. En ambos lugares se completó el estudio con coloraciones con May Grunwald Giemsa. La diferencia entre el examen en fresco tardío y el fresco inmediato fue de 16,36 puntos a favor de este último. Para obtener resultados equivalentes, si el examen en fresco resultare negativo para T. vaginalis siempre hay que efectuar una coloración de May Grunwald Giemsa. Solo así los valores predictivos de resultados negativos serán comparables