A machine-learning regional clustering approach to understand ventilator-induced lung injury: a proof-of-concept experimental study.

BACKGROUND: The spatiotemporal progression and patterns of tissue deformation in ventilator-induced lung injury (VILI) remain understudied. Our aim was to identify lung clusters based on their regional mechanical behavior over space and time in lungs subjected to VILI using machine-learning techniques. RESULTS: Ten anesthetized pigs (27 ± 2 kg) were studied. Eight subjects were analyzed. End-inspiratory and end-expiratory lung computed tomography scans were performed at the beginning and after 12 h of one-hit VILI model. Regional image-based biomechanical analysis was used to determine end-expiratory aeration, tidal recruitment, and volumetric strain for both early and late stages. Clustering analysis was performed using principal component analysis and K-Means algorithms. We identified three different clusters of lung tissue: Stable, Recruitable Unstable, and Non-Recruitable Unstable. End-expiratory aeration, tidal recruitment, and volumetric strain were significantly different between clusters at early stage. At late stage, we found a step loss of end-expiratory aeration among clusters, lowest in Stable, followed by Unstable Recruitable, and highest in the Unstable Non-Recruitable cluster. Volumetric strain remaining unchanged in the Stable cluster, with slight increases in the Recruitable cluster, and strong reduction in the Unstable Non-Recruitable cluster. CONCLUSIONS: VILI is a regional and dynamic phenomenon. Using unbiased machine-learning techniques we can identify the coexistence of three functional lung tissue compartments with different spatiotemporal regional biomechanical behavior.

Mechanical and morphological characterization of the emphysematous lung tissue.

Irreversible alveolar airspace enlargement is the main characteristic of pulmonary emphysema, which has been extensively studied using animal models. While the alterations in lung mechanics associated with these morphological changes have been documented in the literature, the study of the mechanical behavior of parenchymal tissue from emphysematous lungs has been poorly investigated. In this work, we characterize the mechanical and morphological properties of lung tissue in elastase-induced emphysema rat models under varying severity conditions. We analyze the non-linear tissue behavior using suitable hyperelastic constitutive models that enable to compare different non-linear responses in terms of hyperelastic material parameters. We further analyze the effect of the elastase dose on alveolar morphology and tissue material parameters and study their connection with respiratory-system mechanical parameters. Our results show that while the lung mechanical function is not significantly influenced by the elastase treatment, the tissue mechanical behavior and alveolar morphology are markedly affected by it. We further show a strong association between alveolar enlargement and tissue softening, not evidenced by respiratory-system compliance. Our findings highlight the importance of understanding tissue mechanics in emphysematous lungs, as changes in tissue properties could detect the early stages of emphysema remodeling. STATEMENT OF SIGNIFICANCE: Gas exchange is vital for life and strongly relies on the mechanical function of the lungs. Pulmonary emphysema is a prevalent respiratory disease where alveolar walls are damaged, causing alveolar enlargement that induces harmful changes in the mechanical response of the lungs. In this work, we study how the mechanical properties of lung tissue change during emphysema. Our results from animal models show that tissue properties are more sensitive to alveolar enlargement due to emphysema than other mechanical properties that describe the function of the whole respiratory system.

Routine Kidney Graft Ultrasound After Elective Ureteric Stent Removal: Does it Help?

Transplantation (KTx) is considered to be the best renal replacement therapy, and improving its outcomes remains a primary challenge. KTx ureteral stenting has been used to prevent urological complications, but there is no consensus on the timing of stent removal, and literature regarding routine ultrasonography after ureteric stent removal (RUSUS) to detect complications is lacking. Point-of-care ultrasound has been gaining drive in the medical community in recent years, including nephrologists. We aimed to define the incidence of urological complications diagnosed with RUSUS, if those findings changed patient's management and ultrasound utility. Contrary to previously published data, in our cohort RUSUS allowed a timely diagnosis and early treatment of urological complications, a key factor for successful transplantation. KTx point-of-care ultrasound is a cost-effective and reproducible test that provides relevant information to guide clinical decisions, seeming most efficient when performed approximately 2 weeks post ureteral stent removal. Interventional nephrologists can promptly perform these examinations, reducing waiting times and improving graft and patient's survival.

Impact of Antimicrobial Stewardship Program Intervention Acceptance on Hospital Length of Stay.

Background: Inappropriate antibiotic use is a major public health concern. Excessive exposure to antibiotics results in the proliferation of multidrug-resistant bacteria, increase in potentially avoidable adverse drug reactions, healthcare utilization, and cost. Currently, systematic reviews and controlled trials assessing the effects of antimicrobial stewardship programs (ASP) on hospital length of stay (LOS), mortality, and cost-savings are conflicting. Some studies reported a significant cost-savings driven by shorter hospital LOS while the others found no effect and, in some cases, prolonged LOS. Shortening the time to appropriate therapy and reducing unnecessary days of therapy have been shown to reduce hospital LOS. Objective: The purpose of this study was to evaluate the effects of prescriber acceptance to ASP interventions on hospital LOS. Methods: Between January 2018 and December 2019, 764 charts were retrospectively reviewed for patients who received antimicrobial treatment and in whom an ASP intervention was performed. Patients were allocated into 2 groups: those whose ASP interventions were accepted and those whose were rejected. Provider responses were then documented within 24 hours of being communicated. The primary outcome was hospital LOS. Secondary outcomes included 30-day readmission rates and inpatient antimicrobial duration of therapy (DOT). Results: There were 384 patients with an accepted ASP intervention and 380 with a denied intervention. Baseline characteristics were similar between both groups, except for a difference in the types of intervention performed (P < 0.001). The median hospital LOS for patients in the accepted intervention group was 6.5 days compared to 7 days in the rejected intervention group (P = 0.009). Antimicrobial DOT was also shorter in the accepted intervention group (5 vs 7 days; P < 0.001). There was no difference in 30-day readmission rates (P = 0.98). Conclusion: Prescriber acceptance to ASP interventions decreases hospital LOS and antimicrobial DOT without affecting 30-day readmission rates.

Hormone Receptor-Positive / HER2-Negative Early Breast Cancer High-Risk Population: An Algorithm for Optimization Systemic Adjuvant Treatment Based on 2022 Updates.

Prognostic and predictive factors for early and late distant distance recurrence risk in estrogen-receptor positive and HER2-receptor negative early breast cancer are well known, but not all these variables work equally for the prediction. The following are the most widely accepted variables for categorizing risk levels: clinic-pathologic features (tumor size, lymph node involvement, histological grade, age, menopausal status, Ki-67 expression, estrogen, and progesterone expression), primary systemic treatment response (pathologic response and/or Ki-67 downstaging), and gene expression signatures stratification. Treatment guidelines from cancer societies and collaborative groups, online predict-tools, real-world data and experts' opinion recommends different adjuvant strategies (chemotherapy, endocrine therapy, ovarian suppression, olaparib, or abemaciclib) depending on the low (< 10%), intermediate (10%-20%) or high-risk of distance recurrence at least in the first 5 years. Multiple randomized prospective trials were updated in 2022, that evidence allow us to perform a stratification of risk in pre- and postmenopausal women with estrogen-receptor positive and HER2-receptor negative early breast cancer based on a combination of clinic-pathologic features and genomic assays and guide the adjuvant systemic treatment recommendation for those with high risk.

WarpPINN: Cine-MR image registration with physics-informed neural networks.

The diagnosis of heart failure usually includes a global functional assessment, such as ejection fraction measured by magnetic resonance imaging. However, these metrics have low discriminate power to distinguish different cardiomyopathies, which may not affect the global function of the heart. Quantifying local deformations in the form of cardiac strain can provide helpful information, but it remains a challenge. In this work, we introduce WarpPINN, a physics-informed neural network to perform image registration to obtain local metrics of heart deformation. We apply this method to cine magnetic resonance images to estimate the motion during the cardiac cycle. We inform our neural network of the near-incompressibility of cardiac tissue by penalizing the Jacobian of the deformation field. The loss function has two components: an intensity-based similarity term between the reference and the warped template images, and a regularizer that represents the hyperelastic behavior of the tissue. The architecture of the neural network allows us to easily compute the strain via automatic differentiation to assess cardiac activity. We use Fourier feature mappings to overcome the spectral bias of neural networks, allowing us to capture discontinuities in the strain field. The algorithm is tested on synthetic examples and on a cine SSFP MRI benchmark of 15 healthy volunteers, where it is trained to learn the deformation mapping of each case. We outperform current methodologies in landmark tracking and provide physiological strain estimations in the radial and circumferential directions. WarpPINN provides precise measurements of local cardiac deformations that can be used for a better diagnosis of heart failure and can be used for general image registration tasks. Source code is available at https://github.com/fsahli/WarpPINN.

Morphometric analysis of airways in pre-COPD and mild COPD lungs using continuous surface representations of the bronchial lumen.

Introduction: Chronic Obstructive Pulmonary Disease (COPD) is a prevalent respiratory disease that presents a high rate of underdiagnosis during onset and early stages. Studies have shown that in mild COPD patients, remodeling of the small airways occurs concurrently with morphological changes in the proximal airways. Despite this evidence, the geometrical study of the airway tree from computed tomography (CT) lung images remains underexplored due to poor representations and limited tools to characterize the airway structure. Methods: We perform a comprehensive morphometric study of the proximal airways based on geometrical measures associated with the different airway generations. To this end, we leverage the geometric flexibility of the Snakes IsoGeometric Analysis method to accurately represent and characterize the airway luminal surface and volume informed by CT images of the respiratory tree. Based on this framework, we study the airway geometry of smoking pre-COPD and mild COPD individuals. Results: Our results show a significant difference between groups in airway volume, length, luminal eccentricity, minimum radius, and surface-area-to-volume ratio in the most distal airways. Discussion: Our findings suggest a higher degree of airway narrowing and collapse in COPD patients when compared to pre-COPD patients. We envision that our work has the potential to deliver a comprehensive tool for assessing morphological changes in airway geometry that take place in the early stages of COPD.

Criterios para la identificación de síndromes de cáncer de mama hereditarios. Revisión de la literatura y recomendaciones para el Instituto Nacional de Cancerología - Colombia / Criteria for the identification of hereditary breast cancer syndromes. Review of the literature and recommendations for the Instituto Nacional de Cancerología - Colombia

Introducción. Los síndromes de cáncer de mama hereditario (SCMH) corresponden a un 5% a 10% de todos los casos de la enfermedad, en su mayoría explicados por mutaciones en los genes BRCA1 y BRCA2. Se han publicado múltiples guías y recomendaciones internacionales actualizadas, con el fin de dar lineamientos para seleccionar los casos con sospecha de un SCMH. Como antecedentes locales, el Instituto Nacional de Cancerología de Colombia cuenta con un "Programa institucional para la identificación y manejo de familias con sospecha de cáncer hereditario", con fines asistenciales, dentro del cual el cáncer de mama es la patología más remitida al servicio de genética (55%; 540/986). En el 21% de los casos con cáncer de mama que cumplieron criterios NCCN se diagnosticó un SCMH, la mayoría asociados a mutaciones en los genes BRCA1 y BRCA2 (12,3%) y en menor proporción a otros genes de susceptibilidad al cáncer de mama (8,6%).Objetivo. Identificar los criterios de selección más implementados para diagnosticar los casos de cáncer de mama hereditarios a través de una revisión de la literatura, y realizar un consenso Institucional sobre las indicaciones de remisión a consejería genética y solicitud de pruebas para fines diagnósticos y de tratamiento sistémico con iPARP. Materiales y métodos. Se realizó una revisión narrativa de la literatura científica publicada en los últimos 10 años, al 30 de agosto del 2021, sobre la prevalencia de mutaciones germinales en los genes BRCA1 y BRCA2, y en otros genes no BRCA, en pacientes con cáncer de mama, obteniéndose en total 146 y seleccionándose un total de 41 artículos. En el interior de las unidades funcionales de mama y tejidos blandos, genética y oncología clínica, se presentó la evidencia disponible, realizando una discusión amplia entre las tres unidades y finalmente se definieron las indicaciones para remisión a genética, para solicitar estudios genéticos y de tratamiento sistémico con iPARP.Resultados. Según lo reportado en la literatura, los principales criterios de sospecha de un SCMH deben incluir: el subtipo triple negativo, la presentación bilateral, la edad muy temprana de diagnóstico y los antecedentes familiares (AF) de cáncer de mama antes de los 50 años o cáncer de ovario a cualquier edad.Conclusiones. Se adoptan las recomendaciones de la NCCN para la remisión a consejería genética y solicitud de estudios genéticos para identificar cáncer de mama hereditario, y se establecen los criterios del estudio OlympiA para la solicitud de estudios genéticos con el fin de guiar el tratamiento sistémico con iPARP en el Instituto Nacional de Cancerología. Lo anterior permitirá que desde nuestra Institución se ofrezca adecuadamente este servicio a la población colombiana.

ntroduction: Hereditary breast and ovarian cancer syndromes (HBOC) represents 5% to 10% of all breast cancer cases, and BRCA1andBRCA2 explain most of these syndromes. Multiple guidelines and updated recommendations have been published to define which patients should be selected for genetic testing based on a clinical suspicion of a HBOC syndrome. For context, the Instituto Nacional de Cancerología from Colombia developed an "Institutional Program for the identification and management of families with suspected hereditary cancer" for healthcare purposes, within which breast cancer is the most referred pathology to the genetics service (55%; 540/986). Inherited cancer was diagnosed in 21% of the patients with breast cancer who met NCCN criteria; most of these were associated with BRCA1 and BRCA2 mutations (12.3%) and to a lesser extent to other breast cancer susceptibility genes (8.6%).Objective: To identify the most implemented selection criteria to diagnose inherited breast cancer cases, through a review of the literature, and to achieve an institutional consensus on the indications for referral to genetic counseling and genetic testing for diagnostic and systemic treatment with PARPi.Materials and methods: A narrative review of the scientific literature published in the last 10 years as of August 30, 2021 on the prevalence of germline mutations in the BRCA1 and BRCA2 genes, and in other non-BRCA genes, in patients with breast cancer was carried out. Overall, 146 articles were first identified but only 41 were selected. Within the functional units of breast and soft tissue, genetics and clinical oncology, the available evidence was presented and a broad discussion was carried out; finally the indications for referral to genetic counseling, for genetic testing and for systemic treatment with PARPi were defined.Results: As reported in the literature, clinical criteria for HBOC syndrome should include: triple negative subtype, bilateral presentation, very early age of diagnosis and family history (FH) of breast cancer before 50 years of age or ovarian cancer at any age. Conclusions: The NCCN recommendations for referral to genetic counseling and ordering genetic testing to diagnose HBOC cases are adopted at the Instituto Nacional de Cancerología from Colombia, as well as the OlympiA study criteria for ordering genetic testing to guide systemic PARPi therapy. This will allow our Institution to adequately offer this service to the Colombian population.

Estudios de extensión para la estadificación del cáncer de mama infiltrante. Revisión de la evidencia y abordaje terapéutico en el Instituto Nacional de Cancerología - Colombia / Extension studies for the staging of infiltrating breast cancer. Review of evidence and therapeutic approach at the Instituto Nacional de Cancerología - Colombia

La estadificación del cáncer de mama tiene como objetivo determinar la extensión de la enfermedad, definir el tratamiento y el pronóstico de la misma. La American Joint Committee on Cancer(AJCC) ha asignado el estadio utilizando el tamaño del tumor (T), la presencia de compromiso ganglionar (N), y la presencia o ausencia de metástasis a distancia (M). Con el advenimiento de la biología molecular, se integra a la estadificación anatómica la información pronóstica con el grado histológico, el estado de los receptores hormonales y el resultado del receptor de HER2. En el Instituto Nacional de Cancerología (INC), la incorporación del TNM pronóstico trajo consigo un aumento de estadio en el 14,47% de los casos y una disminución en el 40,3%; este resultado se atribuyó en parte al mayor porcentaje de tumores localmente avanzados dentro de la institución. Por subtipo biológico, los tumores luminales presentan mayor riesgo de metástasis óseas, los tumores triple negativo a pulmón y sistema nervioso central; y los tumores HER2 a SNC, hígado y pulmón. Teniendo en cuenta este compromiso a distancia, los métodos de estadificación comúnmente utilizados son gammagrafía ósea (GO), radiografía de tórax (RxT), ecografía hepática (UH) y/o tomografía computarizada (TC). En el caso de identificar hallazgos sospechosos en estos exámenes o si el cuadro clínico del paciente lo sugiere, se realizan estudios adicionales como TC o resonancia magnética nuclear (RMN). Los cambios en la estadificación clínica y la biología del cáncer de mama motivaron a las Unidades de Seno y Tejidos Blandos y Oncología Clínica del Instituto Nacional de Cancerología a revisar la evidencia científica disponible para recomendar la pertinencia de los estudios de extensión.

The staging of breast cancer has the objective to determine the extent of the disease, define treatment and prognosis. The American Joint Committee on Cancer (AJCC) has assigned the stage using the size of the tumor (T), the presence of lymph node involvement (N), and the presence or absence of distant metastases (M). With the advent of molecular biology, prognostic information with histological grade, hormone receptor status, and HER2 receptor is integrated with anatomic staging. In the National Institute of Cancerology (INC) the incorporation of TNM brought with it an increase in stage in 14.47% of cases and a decrease in 40.3%; this result was attributed in part to the higher percentage of locally advanced tumors within the institution. By biological subtype, luminal tumors have a higher risk of bone metastases, triple negative tumors to the lung and central nervous system; and HER2 tumors to CNS, liver and lung. Taking this distant involvement into account, the commonly used staging methods are bone scan (BS), chest radiography (CXR), liver ultrasound (UH) and/or computed tomography (CT) scans. In the case of identifying suspicious findings in these tests or if the patient's clinical condition suggests it, additional studies such as CT or magnetic resonance imaging (MRI) are performed. Changes in the clinical staging and biology of breast cancer motivated the Breast and Clinical Oncology Functional Unit of the National Cancer Institute to review the available scientific evidence to recommend the relevance of extension studies.

Whole-lung finite-element models for mechanical ventilation and respiratory research applications.

Mechanical ventilation has been a vital treatment for Covid-19 patients with respiratory failure. Lungs assisted with mechanical ventilators present a wide variability in their response that strongly depends on air-tissue interactions, which motivates the creation of simulation tools to enhance the design of ventilatory protocols. In this work, we aim to create anatomical computational models of the lungs that predict clinically-relevant respiratory variables. To this end, we formulate a continuum poromechanical framework that seamlessly accounts for the air-tissue interaction in the lung parenchyma. Based on this formulation, we construct anatomical finite-element models of the human lungs from computed-tomography images. We simulate the 3D response of lungs connected to mechanical ventilation, from which we recover physiological parameters of high clinical relevance. In particular, we provide a framework to estimate respiratory-system compliance and resistance from continuum lung dynamic simulations. We further study our computational framework in the simulation of the supersyringe method to construct pressure-volume curves. In addition, we run these simulations using several state-of-the-art lung tissue models to understand how the choice of constitutive models impacts the whole-organ mechanical response. We show that the proposed lung model predicts physiological variables, such as airway pressure, flow and volume, that capture many distinctive features observed in mechanical ventilation and the supersyringe method. We further conclude that some constitutive lung tissue models may not adequately capture the physiological behavior of lungs, as measured in terms of lung respiratory-system compliance. Our findings constitute a proof of concept that finite-element poromechanical models of the lungs can be predictive of clinically-relevant variables in respiratory medicine.

Fully Three-Dimensional Hemodynamic Characterization of Altered Blood Flow in Bicuspid Aortic Valve Patients With Respect to Aortic Dilatation: A Finite Element Approach.

Background and Purpose: Prognostic models based on cardiovascular hemodynamic parameters may bring new information for an early assessment of patients with bicuspid aortic valve (BAV), playing a key role in reducing the long-term risk of cardiovascular events. This work quantifies several three-dimensional hemodynamic parameters in different patients with BAV and ranks their relationships with aortic diameter. Materials and Methods: Using 4D-flow CMR data of 74 patients with BAV (49 right-left and 25 right-non-coronary) and 48 healthy volunteers, aortic 3D maps of seventeen 17 different hemodynamic parameters were quantified along the thoracic aorta. Patients with BAV were divided into two morphotype categories, BAV-Non-AAoD (where we include 18 non-dilated patients and 7 root-dilated patients) and BAV-AAoD (where we include the 49 patients with dilatation of the ascending aorta). Differences between volunteers and patients were evaluated using MANOVA with Pillai's trace statistic, Mann-Whitney U test, ROC curves, and minimum redundancy maximum relevance algorithm. Spearman's correlation was used to correlate the dilation with each hemodynamic parameter. Results: The flow eccentricity, backward velocity, velocity angle, regurgitation fraction, circumferential wall shear stress, axial vorticity, and axial circulation allowed to discriminate between volunteers and patients with BAV, even in the absence of dilation. In patients with BAV, the diameter presented a strong correlation (> |+/-0.7|) with the forward velocity and velocity angle, and a good correlation (> |+/-0.5|) with regurgitation fraction, wall shear stress, wall shear stress axial, and vorticity, also for morphotypes and phenotypes, some of them are correlated with the diameter. The velocity angle proved to be an excellent biomarker in the differentiation between volunteers and patients with BAV, BAV morphotypes, and BAV phenotypes, with an area under the curve bigger than 0.90, and higher predictor important scores. Conclusions: Through the application of a novel 3D quantification method, hemodynamic parameters related to flow direction, such as flow eccentricity, velocity angle, and regurgitation fraction, presented the best relationships with a local diameter and effectively differentiated patients with BAV from healthy volunteers.

Distribution and Magnitude of Regional Volumetric Lung Strain and Its Modification by PEEP in Healthy Anesthetized and Mechanically Ventilated Dogs.

The present study describes the magnitude and spatial distribution of lung strain in healthy anesthetized, mechanically ventilated dogs with and without positive end-expiratory pressure (PEEP). Total lung strain (LSTOTAL) has a dynamic (LSDYNAMIC) and a static (LSSTATIC) component. Due to lung heterogeneity, global lung strain may not accurately represent regional total tissue lung strain (TSTOTAL), which may also be described by a regional dynamic (TSDYNAMIC) and static (TSSTATIC) component. Six healthy anesthetized beagles (12.4 ± 1.4 kg body weight) were placed in dorsal recumbency and ventilated with a tidal volume of 15 ml/kg, respiratory rate of 15 bpm, and zero end-expiratory pressure (ZEEP). Respiratory system mechanics and full thoracic end-expiratory and end-inspiratory CT scan images were obtained at ZEEP. Thereafter, a PEEP of 5 cmH2O was set and respiratory system mechanics measurements and end-expiratory and end-inspiratory images were repeated. Computed lung volumes from CT scans were used to evaluate the global LSTOTAL, LSDYNAMIC, and LSSTATIC during PEEP. During ZEEP, LSSTATIC was assumed zero; therefore, LSTOTAL was the same as LSDYNAMIC. Image segmentation was applied to CT images to obtain maps of regional TSTOTAL, TSDYNAMIC, and TSSTATIC during PEEP, and TSDYNAMIC during ZEEP. Compliance increased (p = 0.013) and driving pressure decreased (p = 0.043) during PEEP. PEEP increased the end-expiratory lung volume (p < 0.001) and significantly reduced global LSDYNAMIC (33.4 ± 6.4% during ZEEP, 24.0 ± 4.6% during PEEP, p = 0.032). LSSTATIC by PEEP was larger than the reduction in LSDYNAMIC; therefore, LSTOTAL at PEEP was larger than LSDYNAMIC at ZEEP (p = 0.005). There was marked topographic heterogeneity of regional strains. PEEP induced a significant reduction in TSDYNAMIC in all lung regions (p < 0.05). Similar to global findings, PEEP-induced TSSTATIC was larger than the reduction in TSDYNAMIC; therefore, PEEP-induced TSTOTAL was larger than TSDYNAMIC at ZEEP. In conclusion, PEEP reduced both global and regional estimates of dynamic strain, but induced a large static strain. Given that lung injury has been mostly associated with tidal deformation, limiting dynamic strain may be an important clinical target in healthy and diseased lungs, but this requires further study.

Determination of the Respiratory Compensation Point by Detecting Changes in Intercostal Muscles Oxygenation by Using Near-Infrared Spectroscopy.

This study aimed to evaluate if the changes in oxygen saturation levels at intercostal muscles (SmO2-m.intercostales) assessed by near-infrared spectroscopy (NIRS) using a wearable device could determine the respiratory compensation point (RCP) during exercise. Fifteen healthy competitive triathletes (eight males; 29 ± 6 years; height 167.6 ± 25.6 cm; weight 69.2 ± 9.4 kg; V˙O2-máx 58.4 ± 8.1 mL·kg−1·min−1) were evaluated in a cycle ergometer during the maximal oxygen-uptake test (V˙O2-máx), while lung ventilation (V˙E), power output (watts, W) and SmO2-m.intercostales were measured. RCP was determined by visual method (RCPvisual: changes at ventilatory equivalents (V˙E·V˙CO2−1, V˙E·V˙O2−1) and end-tidal respiratory pressure (PetO2, PetCO2) and NIRS method (RCPNIRS: breakpoint of fall in SmO2-m.intercostales). During exercise, SmO2-m.intercostales decreased continuously showing a higher decrease when V˙E increased abruptly. A good agreement between methods used to determine RCP was found (visual vs NIRS) at %V˙O2-máx, V˙O2, V˙E, and W (Bland-Altman test). Correlations were found to each parameters analyzed (r = 0.854; r = 0.865; r = 0.981; and r = 0,968; respectively. p < 0.001 in all variables, Pearson test), with no differences (p < 0.001 in all variables, Student's t-test) between methods used (RCPvisual and RCPNIRS). We concluded that changes at SmO2-m.intercostales measured by NIRS could adequately determine RCP in triathletes.

Hyaline cartilage differentiation of fibroblasts in regeneration and regenerative medicine.

Amputation injuries in mammals are typically non-regenerative; however, joint regeneration is stimulated by BMP9 treatment, indicating the presence of latent articular chondrocyte progenitor cells. BMP9 induces a battery of chondrogenic genes in vivo, and a similar response is observed in cultures of amputation wound cells. Extended cultures of BMP9-treated cells results in differentiation of hyaline cartilage, and single cell RNAseq analysis identified wound fibroblasts as BMP9 responsive. This culture model was used to identify a BMP9-responsive adult fibroblast cell line and a culture strategy was developed to engineer hyaline cartilage for engraftment into an acutely damaged joint. Transplanted hyaline cartilage survived engraftment and maintained a hyaline cartilage phenotype, but did not form mature articular cartilage. In addition, individual hypertrophic chondrocytes were identified in some samples, indicating that the acute joint injury site can promote osteogenic progression of engrafted hyaline cartilage. The findings identify fibroblasts as a cell source for engineering articular cartilage and establish a novel experimental strategy that bridges the gap between regeneration biology and regenerative medicine.

Physiological and metabolic alterations in basil (Ocimum basilicum L) varieties under distinct soil water levels / Alteraciones fisiológicas y metabólicas en variedades de albahaca (Ocimum basilicum L) bajo distintos niveles de agua del suelo

Basil (Ocimum basilicumL.) is a medicinal species used in several areas, such as food, medicines and cosmetics, and the understanding of its physiological behavior under environmental conditions is of paramount importance for the improvement of cultivation methods. The objective of this study was to evaluate the influence of different water availability under physiological, biochemical and metabolic characteristics, in three distinct genotypes: 'Alfavaca basilicão', 'Gennaro de menta' and 'Grecco à palla', during two different phenological stages (vegetative and reproductive). It was found that the water deficit promotes physiological changes to tolerate water stress, and the studied genotypes have different routes to achieve this physiological tolerance, which culminates in a distinct accumulation of metabolites in plants, and can be considered interesting if the final product is the production of essential oils.

La albahaca (Ocimum basilicum L.) es una planta medicinal utilizada en varias áreas: alimenticia, medicinal e industria cosmética; es de suma importancia el entendimiento de su comportamiento fisiológico bajo diferentes condiciones ambientales con el fin de mejorar los procesos del cultivo. El objetivo de este estudio fue evaluar la influencia de diferentes disponibilidades hídricas en las características fisiológicas, bioquímicas y metabólicas en tres genotipos de albahaca: "Alfavaca basilicão", "Gennaro de menta" y "Grecco à palla" durante dos etapas fenológicas (vegetativa y reproductiva). Fue encontrado que el déficit hídrico promueve cambios fisiológicos con el fin de tolerar el estrés hídrico. Los genotipos estudiados presentaron diferentes rutas para alcanzar esta tolerancia fisiológica, la cual culmina con distintas acumulaciones de metabolitos en las plantas, y puede ser considerado interesante si el producto final es la producción de aceites esenciales.

Three-Dimensional Whole-Organ Characterization of the Regional Alveolar Morphology in Normal Murine Lungs.

Alveolar architecture plays a fundamental role in the processes of ventilation and perfusion in the lung. Alterations in the alveolar surface area and alveolar cavity volume constitute the pathophysiological basis of chronic respiratory diseases such as pulmonary emphysema. Previous studies based on micro-computed tomography (micro-CT) of lung samples have allowed the geometrical study of acinar units. However, our current knowledge is based on the study of a few tissue samples in random locations of the lung that do not give an account of the spatial distributions of the alveolar architecture in the whole lung. In this work, we combine micro-CT imaging and computational geometry algorithms to study the regional distribution of key morphological parameters throughout the whole lung. To this end, 3D whole-lung images of Sprague-Dawley rats are acquired using high-resolution micro-CT imaging and analyzed to estimate porosity, alveolar surface density, and surface-to-volume ratio. We assess the effect of current gold-standard dehydration methods in the preparation of lung samples and propose a fixation protocol that includes the application of a methanol-PBS solution before dehydration. Our results show that regional porosity, alveolar surface density, and surface-to-volume ratio have a uniform distribution in normal lungs, which do not seem to be affected by gravitational effects. We further show that sample fixation based on ethanol baths for dehydration introduces shrinking and affects the acinar architecture in the subpleural regions. In contrast, preparations based on the proposed dehydration protocol effectively preserve the alveolar morphology.

Pultruded FRP Beams with Embedded Fibre Bragg Grating Optical Sensors for Strain Measurement and Failure Detection.

Composites have added new dimensions to the design and construction of buildings and structures. One of the wider spread composite applications in the construction industry is composite beams or pillars, which can be manufactured through pultrusion processes. These types of construction elements are usually used to withstand the weight of large loads, so their integrity must be guaranteed. Due to optical sensors' advantages over their electrical counterparts-small sizes, low weight, non-conductive, and immunity to electromagnetic interference-and FBGs having an outstanding position among optical fibre sensors-due to their multiplexation capability and relatively easy monitoring-in this study, we propose the integration of FBG sensors for the observation and analysis of the integrity of structures made with composite beams over time. The validation test results showed the successful embedding integration of FBG-based fibre optical sensors in an FRP pultrusion beam and strain transmission up to 7500 µÉ› from the composite test piece to the sensor. Additionally, we were able to anticipate the piece failure by the FBG spectrum deformation.

Detoxification of phenanthrene in Arabidopsis thaliana involves a Dioxygenase For Auxin Oxidation 1 (AtDAO1).

Polycyclic aromatic hydrocarbon (PAH) contamination has a negative impact on ecosystems. PAHs are a large group of toxins with two or more benzene rings that are persistent in the environment. Some PAHs can be cytotoxic, teratogenic, and/or carcinogenic. In the bacterium Pseudomonas, PAHs can be modified by dioxygenases, which increase the reactivity of PAHs. We hypothesize that some plant dioxygenases are capable of PAH biodegradation. Herein, we investigate the involvement of Arabidopsis thaliana At1g14130 in the degradation of phenanthrene, our model PAH. The At1g14130 gene encodes Dioxygenase For Auxin Oxidation 1 (AtDAO1), an enzyme involved in the oxidative inactivation of the hormone auxin. Expression analysis using a ß-glucuronidase (GUS) reporter revealed that At1g14130 is prominently expressed in new leaves of plants exposed to media with phenanthrene. Analysis of the oxidative state of gain-of-function mutants showed elevated levels of H2O2 after phenanthrene treatments, probably due to an increase in the oxidation of phenanthrene by AtDAO1. Biochemical assays with purified AtDAO1 and phenanthrene suggest an enzymatic activity towards the PAH. Thus, data presented in this study support the hypothesis that an auxin dioxygenase, AtDAO1, from Arabidopsis thaliana contributes to the degradation of phenanthrene and that there is possible toxic metabolite accumulation after PAH exposure.

Evaluation of Lung Aeration and Respiratory System Mechanics in Obese Dogs Ventilated With Tidal Volumes Based on Ideal vs. Current Body Weight.

We describe the respiratory mechanics and lung aeration in anesthetized obese dogs ventilated with tidal volumes (VT) based on ideal (VTi) vs. current (VTc) body weight. Six dogs with body condition scores ≥ 8/9 were included. End-expiratory respiratory mechanics and end-expiratory CT-scan were obtained at baseline for each dog. Thereafter, dogs were ventilated with VT 15 ml kg-1 based on VTi and VTc, applied randomly. Respiratory mechanics and CT-scan were repeated at end-inspiration during VTi and VTc. Data analyzed with linear mixed models and reported as mean ± SD or median [range]. Statistical significance p < 0.05. The elastance of the lung, chest wall and respiratory system indexed by ideal body weight (IBW) were positively correlated with body fat percentage, whereas the functional residual capacity indexed by IBW was negatively correlated with body fat percentage. At end-expiration, aeration (%) was: hyperaeration 0.03 [0.00-3.35], normoaeration 69.7 [44.6-82.2], hypoaeration 29.3 [13.6-49.4] and nonaeration (1.06% [0.37-6.02]). Next to the diaphragm, normoaeration dropped to 12 ± 11% and hypoaeration increased to 90 ± 8%. No differences in aeration between groups were found at end-inspiration. Airway driving pressure (cm H2O) was higher (p = 0.002) during VTc (9.8 ± 0.7) compared with VTi (7.6 ± 0.4). Lung strain was higher (p = 0.014) during VTc (55 ± 21%) than VTi (38 ± 10%). The stress index was higher (p = 0.012) during VTc (SI = 1.07 [0.14]) compared with VTi (SI = 0.93 [0.18]). This study indicates that body fat percentage influences the magnitude of lung, chest wall, and total respiratory system elastance and resistance, as well as functional residual capacity. Further, these results indicate that obese dogs have extensive areas of hypoaerated lungs, especially in caudodorsal regions. Finally, lung strain and airway driving pressure, surrogates of lung deformation, are higher during VTc than during VTi, suggesting that in obese anesthetized dogs, ventilation protocols based on IBW may be advantageous.