Self-Healing Photocurable Epoxy/thiol-ene Systems Using an Aromatic Epoxy Resin

A rapid and efficient method to obtain self-healing epoxy resins is discussed. This method is based on the use of a thiol-disulfide oligomer obtained by partial oxidation of a multifunctional thiol using a hypervalent iodine (III) compound as oxidant. The oligomer was characterized by Fourier transform infrared spectroscopy (FTIR), Raman and nuclear magnetic resonance spectroscopies, and gel permeation chromatography (GPC). The oligomer was a joint component of the thiol-ene system along with a tetra-allyl-functionalized curing agent. The kinetics of the photopolymerization of diglycidylether of bisphenol A (DGEBA) revealed that conversions of the epoxy groups as high as 80% were achieved in only 15 minutes by increasing the concentration of the thiol-ene system in the formulation. The disulfide bonds introduced in the copolymer using the thiol-disulfide oligomer allowed the repairing of the test specimens in as little as 10 minutes when the specimens were heated at 80°C or for 500 minutes at room temperature. The analysis of the mechanical properties using dynamic mechanical analysis (DMA) showed that the specimens displayed a healing efficiency up to 111% compared with the unhealed specimens, depending on the amount of polythioethers present in the copolymer

Intralesional infiltrations of arteriosclerotic tissue cells-free filtrate reproduce vascular pathology in healthy recipient rats

Lower-extremity arterial disease is a major health problem with increasing prevalence, often leading to non-traumatic amputation, disability and mortality. The molecular mechanisms underpinning abnormal vascular wall remodeling are not fully understood. We hypothesized on the existence of a vascular tissue memory that may be transmitted through soluble signaling messengers, transferred from humans to healthy recipient animals, and consequently drive the recapitulation of arterial wall thickening and other vascular pathologies. We examined the effects of the intralesional infiltration for 6 days of arteriosclerotic popliteal artery-derived homogenates (100 µg of protein) into rats’ full-thickness wounds granulation tissue. Animals infiltrated with normal saline solution or healthy brachial arterial tissue homogenate obtained from traumatic amputation served as controls. The significant thickening of arteriolar walls was the constant outcome in two independent experiments for animals receiving arteriosclerotic tissue homogenates. This material induced other vascular morphological changes including an endothelial cell phenotypic reprogramming that mirrored the donor’s vascular histopathology. The immunohistochemical expression pattern of relevant vascular markers appeared to match between the human tissue and the corresponding recipient rats. These changes occurred within days of administration, and with no cross-species limitation. The identification of these “vascular disease drivers” may pave novel research avenues for atherosclerosis pathobiology

An individual based computational model of intestinal crypt fission and its application to predicting unrestrictive growth of the intestinal epithelium.

Intestinal crypt fission is a homeostatic phenomenon, observable in healthy adult mucosa, but which also plays a pathological role as the main mode of growth of some intestinal polyps. Building on our previous individual based model for the small intestinal crypt and on in vitro cultured intestinal organoids, we here model crypt fission as a budding process based on fluid mechanics at the individual cell level and extrapolated predictions for growth of the intestinal epithelium. Budding was always observed in regions of organoids with abundant Paneth cells. Our data support a model in which buds are biomechanically initiated by single stem cells surrounded by Paneth cells which exhibit greater resistance to viscoelastic deformation, a hypothesis supported by atomic force measurements of single cells. Time intervals between consecutive budding events, as simulated by the model and observed in vitro, were 2.84 and 2.62 days, respectively. Predicted cell dynamics was unaffected within the original crypt which retained its full capability of providing cells to the epithelium throughout fission. Mitotic pressure in simulated primary crypts forced upward migration of buds, which simultaneously grew into new protruding crypts at a rate equal to 1.03 days-1 in simulations and 0.99 days-1 in cultured organoids. Simulated crypts reached their final size in 4.6 days, and required 40 6.2 days to migrate to the top of the primary crypt. The growth of the secondary crypt is independent of its migration along the original crypt. Assuming unrestricted crypt fission and multiple budding events, a maximal growth rate of the intestinal epithelium of 0.10 days-1 43 is predicted and thus approximately 22 days are required for a 10-fold increase of polyp size. These predictions are in agreement with the time reported to develop macroscopic adenomas in mice after loss of Apc in intestinal stem cells

Depredación por Podisus maculiventris (Say) sobre larvas de Choristoneura rosaceana (Harris)

Choristoneura rosaceana (Harris) es una plaga del manzano Malus domestica Borkh. de reciente aparición en México. Su control depende básicamente del uso de insecticidas químicos; sin embargo, existen registros de enemigos naturales de esta plaga que ejercen un control considerable. El objetivo del estudio fue evaluar la capacidad de depredación de Podisus maculiventris (Say) sobre C. rosaceana. Para lo anterior, en agosto y septiembre de 2014, se recolectaron 1200 larvas de C. rosaceana en huertos de manzano. Asimismo, se recolectaron 87 especímenes del depredador P. maculiventris, de diferentes estadios ninfales, de los cuales 75 se recolectaron en huertos de manzano y 17 en parcelas de maíz, además se recolectaron 22 grupos de huevos (17 en maíz y cinco en manzano). Se realizaron ensayos de consumo de P. maculiventris sobre larvas de C. rosaceana, donde el promedio fue de 0.72 larvas consumidas por día, siendo el primer estadio ninfal el que mostró un mayor promedio de consumo (1.9 larvas/día), en las primeras 24 h y el segundo estadio mostró el mayor promedio a los 7 días (1.2 larvas consumidas/día).Choristoneura rosaceana (Harris) es una plaga del manzano Malus domestica Borkh. de reciente aparición en México. Su control depende básicamente del uso de insecticidas químicos; sin embargo, existen registros de enemigos naturales de esta plaga que ejercen un control considerable. El objetivo del estudio fue evaluar la capacidad de depredación de Podisus maculiventris (Say) sobre C. rosaceana. Para lo anterior, en agosto y septiembre de 2014, se recolectaron 1200 larvas de C. rosaceana en huertos de manzano. Asimismo, se recolectaron 87 especímenes del depredador P. maculiventris, de diferentes estadios ninfales, de los cuales 75 se recolectaron en huertos de manzano y 17 en parcelas de maíz, además se recolectaron 22 grupos de huevos (17 en maíz y cinco en manzano). Se realizaron ensayos de consumo de P. maculiventris sobre larvas de C. rosaceana, donde el promedio fue de 0.72 larvas consumidas por día, siendo el primer estadio ninfal el que mostró un mayor promedio de consumo (1.9 larvas/día), en las primeras 24 h y el segundo estadio mostró el mayor promedio a los 7 días (1.2 larvas consumidas/día)

Depredación por Podisus maculiventris (Say) sobre larvas de Choristoneura rosaceana (Harris)

Choristoneura rosaceana (Harris) es una plaga del manzano Malus domestica Borkh. de reciente aparición en México. Su control depende básicamente del uso de insecticidas químicos; sin embargo, existen registros de enemigos naturales de esta plaga que ejercen un control considerable. El objetivo del estudio fue evaluar la capacidad de depredación de Podisus maculiventris (Say) sobre C. rosaceana. Para lo anterior, en agosto y septiembre de 2014, se recolectaron 1200 larvas de C. rosaceana en huertos de manzano. Asimismo, se recolectaron 87 especímenes del depredador P. maculiventris, de diferentes estadios ninfales, de los cuales 75 se recolectaron en huertos de manzano y 17 en parcelas de maíz, además se recolectaron 22 grupos de huevos (17 en maíz y cinco en manzano). Se realizaron ensayos de consumo de P. maculiventris sobre larvas de C. rosaceana, donde el promedio fue de 0.72 larvas consumidas por día, siendo el primer estadio ninfal el que mostró un mayor promedio de consumo (1.9 larvas/día), en las primeras 24 h y el segundo estadio mostró el mayor promedio a los 7 días (1.2 larvas consumidas/día).Choristoneura rosaceana (Harris) es una plaga del manzano Malus domestica Borkh. de reciente aparición en México. Su control depende básicamente del uso de insecticidas químicos; sin embargo, existen registros de enemigos naturales de esta plaga que ejercen un control considerable. El objetivo del estudio fue evaluar la capacidad de depredación de Podisus maculiventris (Say) sobre C. rosaceana. Para lo anterior, en agosto y septiembre de 2014, se recolectaron 1200 larvas de C. rosaceana en huertos de manzano. Asimismo, se recolectaron 87 especímenes del depredador P. maculiventris, de diferentes estadios ninfales, de los cuales 75 se recolectaron en huertos de manzano y 17 en parcelas de maíz, además se recolectaron 22 grupos de huevos (17 en maíz y cinco en manzano). Se realizaron ensayos de consumo de P. maculiventris sobre larvas de C. rosaceana, donde el promedio fue de 0.72 larvas consumidas por día, siendo el primer estadio ninfal el que mostró un mayor promedio de consumo (1.9 larvas/día), en las primeras 24 h y el segundo estadio mostró el mayor promedio a los 7 días (1.2 larvas consumidas/día)

Epidermal growth factor suppresses intestinal epithelial cell shedding both in vitro and in vivo via a MAPK dependent pathway

Cell shedding from the intestinal villus is a key element of tissue turnover, essential to maintain health and homeostasis. However, the signals regulating this process are not well understood. We asked whether shedding is controlled by epidermal growth factor receptor (EGFR), an important driver of intestinal growth and differentiation. In 3D ileal enteroid culture and cell culture models (MDCK, IEC-6, IPEC-J2 cells), extrusion events were suppressed by EGF, as determined by direct counting of released cells or rhodamine-phalloidin labeling of condensed actin rings. Blockade of MEK/ERK, but not other downstream pathways such as PI3K or PKC, reversed EGF inhibition of shedding. These effects were not due to a change in cell viability. Furthermore, EGF-driven MAPK signaling inhibited both caspase-independent and -dependent shedding pathways. Similar results were found in vivo, in a novel zebrafish model for intestinal epithelial shedding. Together, the data show that EGF suppresses cell shedding in the intestinal epithelium through a selective, MAPK dependent pathway affecting multiple extrusion mechanisms. EGFR signaling may be a therapeutic target for disorders featuring excessive cell turnover, such as inflammatory bowel diseases

Impact of preemptive hospitalization on health outcomes at the temporary COVID-19 hospital in Mexico City: a prospective observational study.

INTRODUCTION: In response to the evolution of the coronavirus disease 2019 (COVID-19) pandemic, the admission protocol for the temporary COVID-19 hospital in Mexico City has been updated to hospitalize patients preemptively with an oxygen saturation (SpO2) of >90%. METHODS: This prospective, observational, single-center study compared the progression and outcomes of patients who were preemptively hospitalized versus those who were hospitalized based on an SpO2 ⩽90%. We recorded patient demographics, clinical characteristics, COVID-19 symptoms, and oxygen requirement at admission. We calculated the risk of disease progression and the benefit of preemptive hospitalization, stratified by CALL Score: age, lymphocyte count, and lactate dehydrogenase (<8 and ⩾8) at admission. RESULTS: Preemptive hospitalization significantly reduced the requirement for oxygen therapy (odds ratio 0.45, 95% confidence interval 0.31-0.66), admission to the intensive care unit (ICU) (0.37, 0.23-0.60), requirement for invasive mechanical ventilation (IMV) (0.40, 0.25-0.64), and mortality (0.22, 0.10-0.50). Stratification by CALL score at admission showed that the benefit of preemptive hospitalization remained significant for patients requiring oxygen therapy (0.51, 0.31-0.83), admission to the ICU (0.48, 0.27-0.86), and IMV (0.51, 0.28-0.92). Mortality risk remained significantly reduced (0.19, 0.07-0.48). CONCLUSION: Preemptive hospitalization reduced the rate of disease progression and may be beneficial for improving COVID-19 patient outcomes