Efecto del precondicionamiento hipóxico en la respuesta a un insulto hiperóxico en el sistema nervioso central de ratones recién nacidos

Mammal fetal life elapses in a low oxygen environment relative to the extra uterine. Interestingly, in the human being partial pressure of oxygen increases from fetal 3.3 kPa (25–30 mmHg) to 10.5 kPa (75–85 mmHg) in the first minutes after birth in the newly born infant. This rapid and brisk increase in oxygen availability to tissue generates a physiologic oxidative stress. However, both the lungs and the antioxidant defense system do not mature until late in gestation. Therefore, preterm infants often need respiratory support and oxygen supplementation in the delivery room to achieve postnatal stabilization. The use of supplementary oxygen will cause oxidative stress and damage. In experimental studies in newborn sheep it has been shown that brief resuscitation maneuvers performed in the first minutes after birth produce lung damage and oxidative stress that can have long-lasting consequences. In human newborn infants the use of 100% oxygen instead of air for resuscitation enhances oxidative stress and increases mortality. Furthermore, the use of high oxygen inspired fractions in very preterm infants increased specific morbidities such as bronchopulmonary dysplasia. We hypothesized that delaying oxygenation after birth would preserve reducing equivalents, enhance redox adaptation, and protect the brain against oxygen derived free radicals produced by a hyperoxic insult. The objectives of the study were to determine oxidative stress and damage biomarkers in brain of mice pups during fetal-to-neonatal transition in a breathing atmosphere of FiO2 of 0.14 vs. 0.21. We also studied the consequences of a hyperoxic insult with a FiO2 of 1.0 after postnatal stabilization either with FiO2 of 0.14 or 0.21. Moreover, we analyzed the expression of genes involved in the antioxidant defense system, activation of the expression HIF-1a, inflammation, and the expression of different receptors involved in neurotransmission. Finally, we performed a histological study of different layers of the cerebral cortex to determine morphological changes, apoptosis, and inflammatory changes. Furthermore, we opted to study the effects of perinatal hypoxic preconditioning on mitochondrial morphometry. To proof our hypothesis valid, we designed an experimental model in which we placed pregnant mice in an oxy-cage either with a reduced FiO2 (0.14) or room air (FiO2=0.21) at G18 (8 hours before delivery). 8 hours after birth, both groups were switched to room air (Hx14/21/21 and Nx21/21/21 groups) or subjected to a hyperoxic insult (FiO2=1.0) (Hx14/100/21 and Nx21/100/21) and reset to FiO2=0.21 after 1 hour. Pups were further evaluated either at P1 or kept in the oxy-cage with FiO2=0.21 oxygen until 1 week post-partum (P7). The brains were snap-frozen and kept at -80°C until analysis. We determined the following oxidative stress biomarkers: GSH/GSSG, cysteine/cystine, homocysteine/homocystine ratios, and metabolites of oxidative damage and inflammation such as m-tyr/Phe, o-tyr/Phe, 3NO2-tyr/p-tyr, 3Cl-tyr/p-tyr and 8-OHdG/2dG ratios by liquid chromatography coupled to mass spectrometry (UPLC-MS/MS). In addition, we assessed the expression of antioxidant defense genes, response to HIF-1α, and changes in neurotransmitter receptors by qPCR (both at P1 and P7). Finally, we determined morphology, apoptosis, and inflammation of the different layers of the brain cortex by immunohistochemistry. The mitochondrial morphometry was performed using electron microscopy at P1 mice. In general, we found less oxidative stress and damage to proteins and DNA in the preconditioned hypoxic group. A period of hypoxia after birth seemed to better favor the maintenance of a reducing environment thus protecting them against the switch to a hyperoxic environment. The results obtained in this group were still maintained one week thereafter. In the Hx14/100/21, we found downregulation of antioxidant defense enzymes when compared to the Nx21/100/21 at P1 and P7. Besides, we also observed an upregulation of the HIF-1α targets in mice born under hypoxic conditions. At a histological level, we found higher damage, increased apoptosis and a marked tendency towards inflammation in the cortex of the Nx21/100/21 group when compared to the Hx14/100/21 group. Mitochondria showed better morphology and characteristics during adaptation to re-oxygenation when birth occurred in a hypoxic atmosphere (Hx14/100/21) as opposed to normoxic conditions (Nx21/100/21). We conclude that in mice pups performing fetal-to-neonatal transition under hypoxic conditions (hypoxic preconditioning) and smoothly transitioning to normoxia seemed to better withstand a hyperoxic insult after birth as reflected by less oxidative stress, less damage and less inflammation in brain tissue.Mammal fetal life elapses in a low oxygen environment relative to the extra uterine. Interestingly, in the human being partial pressure of oxygen increases from fetal 3.3 kPa (25–30 mmHg) to 10.5 kPa (75–85 mmHg) in the first minutes after birth in the newly born infant. This rapid and brisk increase in oxygen availability to tissue generates a physiologic oxidative stress. However, both the lungs and the antioxidant defense system do not mature until late in gestation. Therefore, preterm infants often need respiratory support and oxygen supplementation in the delivery room to achieve postnatal stabilization. The use of supplementary oxygen will cause oxidative stress and damage. In experimental studies in newborn sheep it has been shown that brief resuscitation maneuvers performed in the first minutes after birth produce lung damage and oxidative stress that can have long-lasting consequences. In human newborn infants the use of 100% oxygen instead of air for resuscitation enhances oxidative stress and increases mortality. Furthermore, the use of high oxygen inspired fractions in very preterm infants increased specific morbidities such as bronchopulmonary dysplasia. We hypothesized that delaying oxygenation after birth would preserve reducing equivalents, enhance redox adaptation, and protect the brain against oxygen derived free radicals produced by a hyperoxic insult. The objectives of the study were to determine oxidative stress and damage biomarkers in brain of mice pups during fetal-to-neonatal transition in a breathing atmosphere of FiO2 of 0.14 vs. 0.21. We also studied the consequences of a hyperoxic insult with a FiO2 of 1.0 after postnatal stabilization either with FiO2 of 0.14 or 0.21. Moreover, we analyzed the expression of genes involved in the antioxidant defense system, activation of the expression HIF-1a, inflammation, and the expression of different receptors involved in neurotransmission. Finally, we performed a histological study of different layers of the cerebral cortex to determine morphological changes, apoptosis, and inflammatory changes. Furthermore, we opted to study the effects of perinatal hypoxic preconditioning on mitochondrial morphometry. To proof our hypothesis valid, we designed an experimental model in which we placed pregnant mice in an oxy-cage either with a reduced FiO2 (0.14) or room air (FiO2=0.21) at G18 (8 hours before delivery). 8 hours after birth, both groups were switched to room air (Hx14/21/21 and Nx21/21/21 groups) or subjected to a hyperoxic insult (FiO2=1.0) (Hx14/100/21 and Nx21/100/21) and reset to FiO2=0.21 after 1 hour. Pups were further evaluated either at P1 or kept in the oxy-cage with FiO2=0.21 oxygen until 1 week post-partum (P7). The brains were snap-frozen and kept at -80°C until analysis. We determined the following oxidative stress biomarkers: GSH/GSSG, cysteine/cystine, homocysteine/homocystine ratios, and metabolites of oxidative damage and inflammation such as m-tyr/Phe, o-tyr/Phe, 3NO2-tyr/p-tyr, 3Cl-tyr/p-tyr and 8-OHdG/2dG ratios by liquid chromatography coupled to mass spectrometry (UPLC-MS/MS). In addition, we assessed the expression of antioxidant defense genes, response to HIF-1α, and changes in neurotransmitter receptors by qPCR (both at P1 and P7). Finally, we determined morphology, apoptosis, and inflammation of the different layers of the brain cortex by immunohistochemistry. The mitochondrial morphometry was performed using electron microscopy at P1 mice. In general, we found less oxidative stress and damage to proteins and DNA in the preconditioned hypoxic group. A period of hypoxia after birth seemed to better favor the maintenance of a reducing environment thus protecting them against the switch to a hyperoxic environment. The results obtained in this group were still maintained one week thereafter. In the Hx14/100/21, we found downregulation of antioxidant defense enzymes when compared to the Nx21/100/21 at P1 and P7. Besides, we also observed an upregulation of the HIF-1α targets in mice born under hypoxic conditions. At a histological level, we found higher damage, increased apoptosis and a marked tendency towards inflammation in the cortex of the Nx21/100/21 group when compared to the Hx14/100/21 group. Mitochondria showed better morphology and characteristics during adaptation to re-oxygenation when birth occurred in a hypoxic atmosphere (Hx14/100/21) as opposed to normoxic conditions (Nx21/100/21). We conclude that in mice pups performing fetal-to-neonatal transition under hypoxic conditions (hypoxic preconditioning) and smoothly transitioning to normoxia seemed to better withstand a hyperoxic insult after birth as reflected by less oxidative stress, less damage and less inflammation in brain tissue

Hypoxic preconditioning induces neuroprotection against oxidative stress

Brain is an oxyregulator organ, however extremely vulnerable to oxygen. Both high and low oxygen concentrations generate free radicals and may cause oxidative stress and damage because of an insufficient response of the antioxidant system. Hypoxic preconditioning (HP) exerts neuroprotective effects and may be a protecting tool against oxygen fluctuations, thus preventing neuronal damage in events such as ischaemia, acute hypoxia, stroke, or traumatic brain injury, among others. This review aims to discuss the molecular mechanisms involved in the neuroprotective action of HP against oxidative stress and subsequently upon the brain under pro-oxidant conditions. Activation of the antioxidant defences represents the first line to neutralize oxidative stress and is characterized by low reactive oxygen species, reduced oxidative damage biomarkers, and increased level of reduced glutathione. These protective mechanisms decrease cell death activating anti-apoptotic signalling pathways and reducing neuroinflammation by the inactivation of microglia and astroglia cells. HP could be considered a new approach to reduce oxidative stress derived damage caused by a great variety of brain pathologies. Despite our intriguing findings, further experiments are needed for a better understanding of the molecular mechanisms involved in the neuroprotective actions of HP

Impairment of PGC-1 alpha up-regulation enhances nitrosative stress in the liver during acute pancreatitis in obese mice

Acute pancreatitis is an inflammatory process of the pancreatic tissue that often leads to distant organ dysfunction. Although liver injury is uncommon in acute pancreatitis, obesity is a risk factor for the development of hepatic complications. The aim of this work was to evaluate the role of PGC-1α in inflammatory response regulation in the liver and its contribution to the detrimental effect of obesity on the liver during acute pancreatitis. For this purpose, we induced acute pancreatitis by cerulein in not only wild-type (WT) and PGC-1α knockout (KO) mice, but also in lean and obese mice. PGC-1α levels were up-regulated in the mice livers with pancreatitis. The increased PGC-1α levels were bound to p65 to restrain its transcriptional activity toward Nos2. Lack of PGC-1α favored the assembly of the p65/phospho-STAT3 complex, which promoted Nos2 expression during acute pancreatitis. The increased transcript Nos2 levels and the pro-oxidant liver status caused by the down-regulated expression of the PGC-1α-dependent antioxidant genes enhanced nitrosative stress and decreased energy charge in the livers of the PGC-1α KO mice with pancreatitis. It is noteworthy that the PGC-1α levels lowered in the obese mice livers, which increased the Nos2 mRNA expression and protein nitration levels and decreased energy charge during pancreatitis. In conclusion, obesity impairs PGC-1α up-regulation in the liver to cause nitrosative stress during acute pancreatitis.This work was supported by Grant GV/2019/153 from the Generalitat Valenciana, Conselleria d’Educació, Investigació, Cultura I Esport

Construction and validation of a questionnaire of risk and protective factors for drug use in college youth

En este artículo se presenta la construcción y validación del Cuestionario de medición de factores de riesgo y de protección para el consumo de drogas en jóvenes universitarios. Se estableció la validez de contenido, la validez de constructo mediante análisis factoriales y la fiabilidad del cuestionario. La muestra correspondió a 763 estudiantes, entre 15 y 25 años, de una universidad privada de Cali, Colombia. La consistencia interna del cuestionario fue de 0,906 y se definieron seis factores psicosociales de riesgo y protección (malestar emocional, satisfacción en las relaciones interpersonales, preconceptos y valoración de las drogas, espiritualidad, permisividad social y accesibilidad a las drogas y, habilidades sociales y de autocontrol). El instrumento actual constituye una herramienta útil para la evaluación del consumo de drogas y sus factores psicosociales asociados en jóvenes universitarios. No obstante, el cuestionario será aplicado en posteriores estudios con el fin de establecer su validez predictiva.This paper presents the construction and validation of the Risk and protective factors for drug use questionnaire in college youth. Content validity, construct validity and reliability were established. The sample consisted of 763 students between 15 and 25 years old, from a private university in Cali, Colombia. The questionnaire reliability was 0,906, and six psychosocial risk and protective factors were defined (emotional disturbance, satisfaction with interpersonal relations, beliefs and appraisal about drugs, spirituality, social permissiveness and access to drugs, social skills and self-control). The current questionnaire is a useful tool to assess drug use and the psychosocial factors associated to it in college youth. However, it will be administered in later studies in order to establish its predictive validity

Lime mortar-compacted bentonite-magnetite interfaces: An experimental study focused on the understanding of the EBS long-term performance for high-level nuclear waste isolation DGR concept

The aim of this study was to obtain evidences regarding the physical and geochemical processes occurring as a result of the combined effects of cementitious materials from the concrete degradation and magnetite from steel corrosion on the bentonite barrier during disposal of high-level radioactive waste.A series of six experiments were done that attempt to reproduce the repository conditions prevailing from 1000 to 3000 years after emplacement of wastes. A lime mortar was used as the source of calcium and alkalinity as this is the presumed reactive product produced during concrete degradation at long-term. Magnetite powder was used to simulate the final corrosion product of cast iron and C-steel under anaerobic conditions. Either a natural FEBEX bentonite or a pretreated "aged" sample, depleted in exchangeable Mg and enriched in K, were used as the swelling clay component. Experiments, with both types of bentonite, were performed simultaneously in cylindrical specimens (50 mm diameter, 25 mm length), confined in a Teflon® sleeve/steel case cells. These specimens were composed of cement mortar in contact with compacted bentonite, which was in turn in contact with compressed magnetite powder. They were hydrated with an artificial Na+-Ca2+×SO42-type Spanish reference clayey formation water for 18 months at 60 °C and constant hydraulic pressure applied through the base of the mortar.After dismantling and sampling the specimens, distribution of soluble ions, exchangeable cations and mineralogy were studied in the bentonite by different instrumental techniques. Iron migration or any impact of the corrosion products in the bentonite was not noticeable in the clay. Both, mortar and magnetite acted as sinks of chloride and sulfate. Small quantities of Ca-Al-sulfates and carboaluminates, which can allocate chlorides, were determined near the mortar-bentonite interface. Portlandite dissolved near the bentonite interface and induced the formation of calcium silicates hydrates (C-S-H) phases cementing the clay interface characterizing a calcium front that was developed from the mortar towards the bentonite. Magnesium silicate hydrates (M-S-H) phases were also concentrated at the interface with mortar in the natural bentonite. It was also determined that natural bentonite has potentially higher buffering capacity attenuating the calcium alkaline front than the pretreated clay. In both cases, a low porosity bentonite-mortar zone was experimentally created at the interface. This type of material should be carefully studied in order to predict the potential for further development of a diffusive alkaline alteration, the radionuclides retention and the consequences in the hydration rate of the unaffected bentonite bufferThe research leading to these results has received funding from the European Atomic Energy Community's Seventh Framework Program (FP7/2007–2011) under grant agreement no. 249681

Bentonite powder XRD quantitative analysis using Rietveld refinement: Revisiting and updating bulk semiquantitative mineralogical compositions

Bentonite is a claystone formed by a complex mineralogical mixture, composed of mont-morillonite, illite, and accessory minerals like quartz, cristobalite, feldspars, carbonates, and minor amounts of iron oxy-hydroxides. Bentonite presents complexity at various scales: (1): a single mineral may present different chemical composition within the same quarry (e.g., feldspars solid solu-tions); (2): montmorillonite presents variability in the cation-exchange distribution while illite may be presented as mixed-layer with smectite sheets; and (3): hardness and crystal size are larger in accessory minerals than in clay minerals, preventing uniform grinding of bentonite. The FEBEX bentonite used is originally from Almería (Spain), and it is a predominantly calcium, magnesium, and sodium bentonite. This Spanish FEBEX bentonite has been hydrothermally altered at laboratory scale for 7–14 years. A thermal gradient was generated by heating a disk of pressed iron powder, simulating the metal waste canister, in contact with the compacted bentonite sample. Hydration was forced from the opposite direction. XRD recorded patterns were very similar. In order to min-imize the bias of XRD semi-quantitative determination methods, Rietveld refinement was per-formed using BGMN software and different structural models. Confidence in the quantification of the main phases allows us to convincingly detect other subtle changes such as the presence of calcite in the hydration front, right at the interface between the saturated and unsaturated bentonite, or the presence of goethite, and not hematite, in the saturated bentonite, near the source of hydration. Smectite component was 72 ± 3% and the refinement was consistent with the presence of ~10% illite, comparable with previous characterization

HIV screening and retention in care in people who use drugs in Madrid, Spain: a prospective study

Background: The burden of human immunodeficiency virus (HIV) infection in people who use drugs (PWUD) is significant. We aimed to screen HIV infection among PWUD and describe their retention in HIV care. Besides, we also screen for hepatitis C virus (HCV) infection among HIV-seropositive PWUD and describe their linkage to care. Methods: We conducted a prospective study in 529 PWUD who visited the "Cañada Real Galiana" (Madrid, Spain). The study period was from June 1, 2017, to May 31, 2018. HIV diagnosis was performed with a rapid antibody screening test at the point-of-care (POC) and HCV diagnosis with immunoassay and PCR tests on dried blood spot (DBS) in a central laboratory. Positive PWUD were referred to the hospital. We used the Chi-square or Fisher's exact tests, as appropriate, to compare rates between groups. Results: Thirty-five (6.6%) participants were positive HIV antibodies, but 34 reported previous HIV diagnoses, and 27 (76%) had prior antiretroviral therapy. Among patients with a positive HIV antibody test, we also found a higher prevalence of homeless (P < 0.001) and injection drug use (PWID) (P < 0.001), and more decades of drug use (P = 0.002). All participants received HIV test results at the POC. Of the 35 HIV positives, 28 (80%) were retained in HIV medical care at the end of the HIV screening study (2018), and only 22 (62.9%) at the end of 2020. Moreover, 12/35 (34.3%) were positive for the HCV RNA test. Of the latter, 10/12 (83.3%) were contacted to deliver the HCV results test (delivery time of 19 days), 5/12 (41.7%) had an appointment and were attended at the hospital and started HCV therapy, and only 4/12 (33.3%) cleared HCV. Conclusions: We found almost no new HIV-infected PWUD, but their cascade of HIV care was low and remains a challenge in this population at risk. The high frequency of active hepatitis C in HIV-infected PWUD reflects the need for HCV screening and reinforcing the link to care.This work was funded by a research grant from Merck Sharpe & Dohme (Grant Number MISP IIS#54846) and Instituto de Salud Carlos III (ISCII; Grant Numbers PI20CIII/00004, and RD16CIII/0002/0002 to SR). The funders had no role in the study design, data collection, analysis, decision to publish, or preparation of the manuscript.S

Treatment with tocilizumab or corticosteroids for COVID-19 patients with hyperinflammatory state: a multicentre cohort study (SAM-COVID-19)

Objectives: The objective of this study was to estimate the association between tocilizumab or corticosteroids and the risk of intubation or death in patients with coronavirus disease 19 (COVID-19) with a hyperinflammatory state according to clinical and laboratory parameters. Methods: A cohort study was performed in 60 Spanish hospitals including 778 patients with COVID-19 and clinical and laboratory data indicative of a hyperinflammatory state. Treatment was mainly with tocilizumab, an intermediate-high dose of corticosteroids (IHDC), a pulse dose of corticosteroids (PDC), combination therapy, or no treatment. Primary outcome was intubation or death; follow-up was 21 days. Propensity score-adjusted estimations using Cox regression (logistic regression if needed) were calculated. Propensity scores were used as confounders, matching variables and for the inverse probability of treatment weights (IPTWs). Results: In all, 88, 117, 78 and 151 patients treated with tocilizumab, IHDC, PDC, and combination therapy, respectively, were compared with 344 untreated patients. The primary endpoint occurred in 10 (11.4%), 27 (23.1%), 12 (15.4%), 40 (25.6%) and 69 (21.1%), respectively. The IPTW-based hazard ratios (odds ratio for combination therapy) for the primary endpoint were 0.32 (95%CI 0.22-0.47; p < 0.001) for tocilizumab, 0.82 (0.71-1.30; p 0.82) for IHDC, 0.61 (0.43-0.86; p 0.006) for PDC, and 1.17 (0.86-1.58; p 0.30) for combination therapy. Other applications of the propensity score provided similar results, but were not significant for PDC. Tocilizumab was also associated with lower hazard of death alone in IPTW analysis (0.07; 0.02-0.17; p < 0.001). Conclusions: Tocilizumab might be useful in COVID-19 patients with a hyperinflammatory state and should be prioritized for randomized trials in this situatio

Anales del III Congreso Internacional de Vivienda y Ciudad "Debate en torno a la nueva agenda urbana"

Acta de congresoEl III Congreso Internacional de Vivienda y Ciudad “Debates en torno a la NUEVa Agenda Urbana”, ha sido una apuesta de alto compromiso por acercar los debates centrales y urgentes que tensionan el pleno ejercicio del derecho a la ciudad. Para ello las instituciones organizadoras (INVIHAB –Instituto de Investigación de Vivienda y Hábitat y MGyDH-Maestría en Gestión y Desarrollo Habitacional-1), hemos convidado un espacio que se concretó con potencia en un debate transdisciplinario. Convocó a intelectuales de prestigio internacional, investigadores, académicos y gestores estatales, y en una metodología de innovación articuló las voces académicas con las de las organizaciones sociales y/o barriales en el Foro de las Organizaciones Sociales que tuvo su espacio propio para dar voz a quienes están trabajando en los desafíos para garantizar los derechos a la vivienda y los bienes urbanos en nuestras ciudades del Siglo XXI