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BACKGROUNDAlthough convalescent plasma has been widely used to treat severe coronavirus disease 2019 (COVID-19), data from randomized controlled trials that support its efficacy are limited.METHODSWe conducted a randomized, double-blind, controlled trial among adults hospitalized with severe and critical COVID-19 at 5 sites in New York City (USA) and Rio de Janeiro (Brazil). Patients were randomized 2:1 to receive a single transfusion of either convalescent plasma or normal control plasma. The primary outcome was clinical status at 28 days following randomization, measured using an ordinal scale and analyzed using a proportional odds model in the intention-to-treat population.RESULTSOf 223 participants enrolled, 150 were randomized to receive convalescent plasma and 73 to receive normal control plasma. At 28 days, no significant improvement in the clinical scale was observed in participants randomized to convalescent plasma (OR 1.50, 95% confidence interval [CI] 0.83-2.68, P = 0.180). However, 28-day mortality was significantly lower in participants randomized to convalescent plasma versus control plasma (19/150 [12.6%] versus 18/73 [24.6%], OR 0.44, 95% CI 0.22-0.91, P = 0.034). The median titer of anti-SARS-CoV-2 neutralizing antibody in infused convalescent plasma units was 1:160 (IQR 1:80-1:320). In a subset of nasopharyngeal swab samples from Brazil that underwent genomic sequencing, no evidence of neutralization-escape mutants was detected.CONCLUSIONIn adults hospitalized with severe COVID-19, use of convalescent plasma was not associated with significant improvement in day 28 clinical status. However, convalescent plasma was associated with significantly improved survival. A possible explanation is that survivors remained hospitalized at their baseline clinical status.TRIAL REGISTRATIONClinicalTrials.gov, NCT04359810.FUNDINGAmazon Foundation, Skoll Foundation.

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Caveolae-associated protein caveolin-1 (Cav-1) plays key roles in cellular processes such as mechanosensing, receptor coupling to signaling pathways, cell growth, apoptosis, and cancer. In 1321N1 astrocytoma cells Cav-1 interacts with the P2Y2 receptor (P2Y2R) to modulate its downstream signaling. P2Y2R and its signaling machinery also mediate pro-survival actions after mechanical injury. This study determines if Cav-1 knockdown (KD) affects P2Y2R signaling and its pro-survival actions in the 1321N1 astrocytoma cells mechanical injury model system. KD of Cav-1 decreased its expression in 1321N1 cells devoid of or expressing hHAP2Y2R by ~88% and ~85%, respectively. Cav-1 KD had no significant impact on P2Y2R expression. Post-injury densitometric analysis of pERK1/2 and Akt activities in Cav-1-positive 1321N1 cells (devoid of or expressing a hHAP2Y2R) revealed a P2Y2R-dependent temporal increase in both kinases. These temporal increases in pERK1/2 and pAkt were significantly decreased in Cav-1 KD 1321N1 (devoid of or expressing a hHAP2Y2R). Cav-1 KD led to an ~2.0-fold and ~2.4-fold decrease in the magnitude of the hHAP2Y2R-mediated pERK1/2 and pAkt kinases' activity, respectively. These early-onset hHAP2Y2R-mediated signaling responses in Cav-1-expressing and Cav-1 KD 1321N1 correlated with changes in cell viability (via a resazurin-based method) and apoptosis (via caspase-9 expression). In Cav-1-positive 1321N1 cells, expression of hHAP2Y2R led to a significant increase in cell viability and decreased apoptotic (caspase-9) activity after mechanical injury. In contrast, hHAP2Y2R-elicited changes in viability and apoptotic (caspase-9) activity were decreased after mechanical injury in Cav-1 KD 1321N1 cells expressing hHAP2Y2R. These findings support the importance of Cav-1 in modulating P2Y2R signaling during mechanical injury and its protective actions in a human astrocytoma cell line, whilst shedding light on potential new venues for brain injury or trauma interventions.

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Intracellular calcium elevation triggers a wide range of cellular responses. Calcium responses can be affected or modulated by membrane receptors mutations, localization, exposure to agonists/antagonists, among others ( Burgos et al., 2007 ; Martínez et al., 2016 ). Changes in intracellular calcium concentration can be measured using the calcium sensitive fluorescent ratiometric dye fura-2 AM. This method is a high throughput way to measure agonist mediated calcium responses.

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Some receptors that block axonal regeneration or promote cell death after spinal cord injury (SCI) are localized in membrane rafts. Flotillin-2 (Flot-2) is an essential protein associated with the formation of these domains and the clustering of membranal proteins, which may have signaling activities. Our hypothesis is that trauma will change Flot-2 expression and interference of this lipid raft marker will promote functional locomotor recovery after SCI. Analyses were conducted to determine the spatiotemporal profile of Flot-2 expression in adult rats after SCI, using the MASCIS impactor device. Immunoblots showed that SCI produced a significant decrease in the level of Flot-2 at 2 days post-injury (DPI) that increased until 28 DPI. Confocal microscopy revealed Flot-2 expression in neurons, reactive astrocytes and oligodendrocytes specifically associated to myelin structures near or close to the axons of the cord. In the open field test and grid walking assays, to monitor locomotor recovery of injured rats infused intrathecally with Flot-2 antisense oligonucleotides for 28 days showed significant behavioral improvement at 14, 21 and 28 DPI. These findings suggest that Flot-2 has a role in the nonpermissive environment that blocks locomotor recovery after SCI by clustering unfavorable proteins in membrane rafts.

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Judaism has many traditions, customs, rules, and laws, which relate to the proper and ethical disposition of a decedent when a Medical Examiner/ Coroner is involved. In almost all United States jurisdictions, statutes mandate the need to determine the cause and manner of death (Coroners' Act PA Pl. 323, num. 130, section 1237). This article is a review of some religious writings, legal precedents, and forensic authorities, which may help to assist the Medical Examiner/Coroner when confronted with a Jewish decedent. There can be flexibility as to the extent that such forensic studies can and should be performed. The final consent and interpretation of the rules, laws, traditions, and customs will rest with the courts and local rabbinic authority.

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Cholesterol modulates the plasmalemma's biophysical properties and influences the function and trafficking of membrane proteins. A fundamental phenomenon that remains obscure is how the plasmalemma's lipid composition regulates the activatable pool of membrane receptors. An outstanding model to study this phenomenon is the nicotinic acetylcholine receptor (nAChR), since the nAChR activatable pool has been estimated to be but a small fraction of the receptors present in the plasmalemma. Studies on the effect of cholesterol depletion in the function of the Torpedo californica nAChR, using the lipid-exposed nAChR mutation (alpha C418W) that produces a congenital myasthenic syndrome (CMS), demonstrated that cholesterol depletion causes a remarkable increase in the alpha C418W nAChR's macroscopic current whereas not in the wild-type (WT). A variety of approaches were used to define the mechanism responsible for the cholesterol depletion mediated-increase in the alpha C418W nAChR's macroscopic current. The present study suggests that a substantial fraction of the alpha C418W nAChRs is located in caveolin-1-positive domains, "trapped" in a non-activatable state, and that membrane cholesterol depletion results in the relocation of these receptors to the activatable pool. Co-fractionation and co-immunoprecipitation of the alpha C418W nAChR and the membrane raft protein caveolin-1 (cav1) support the notion that interactions at lipid-exposed domains regulate the partition of the receptor into membrane raft microdomains. These results have potential implications as a novel mechanism to fine-tune cholinergic transmission in the nervous system and in the pathogenesis associated to the alpha C418W nAChR.

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Receptor desensitization, or decreased responsiveness of a receptor to agonist stimulation, represents a regulatory process with the potential to have a significant impact on cell behavior. P2Y(2), a G-protein-coupled receptor activated by extracellular nucleotides, undergoes desensitization at many tissues, including the vascular endothelium. Endothelial cells from a variety of vascular beds are normally exposed to extracellular nucleotides released from damaged cells and activated platelets. The purpose of the present study was to compare P2Y(2) receptor desensitization observed in endothelial cells derived from bovine retina, a model of microvascular endothelium, and human umbilical vein endothelial cells (HUVECs), a model of a large blood vessel endothelium. P2Y(2) receptor desensitization was monitored by following changes in UTP-stimulated intracellular free Ca(2 +) in single cells using fura-2 microfluorometry. Both endothelial cell models exhibited desensitization of the P2Y(2) receptor after stimulation with UTP. However, the cells differed in the rate, dependence on agonist concentration, and percentage of maximal desensitization. These results suggest differential mechanisms of P2Y(2) receptor desensitization and favors heterogeneity in extracellular nucleotide activity in endothelial cells according to its vascular bed origin.

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Evidence-based medicine (EBM) integrates the best available external evidence in the care of individual patients with the individual clinical expertise and the patient preferences. This method has been designed for use in daily clinical practice. We describe the rationale for EBM and its principles and application in this article. EBM enables gastroenterologists to update the knowledge required to provide patients with high quality medical care. EBM requires four steps: a) formulating a clinical question arising from a doubt concerning a patient; b) conducting an efficient literature search to answer this question; c) critically appraising this evidence using explicit methods to selected articles to determine the validity of their design and the clinical relevance of their results; and d) applying these results to the patient (taking into account their values and preferences and personal and social circumstances). In this paper, we explain the principles and basic concepts of EBM and their application to gastroenterology and we provide an extensive compilation of internet databases of valid information relevant to gastroenterologists. We also provide a selection of useful tools for self-directed learning of critical appraisal skills. Link updates can be accessed at the following URL: http://www.enlacesmedicos.com/e.htm

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The Rapunzel syndrome is a rare form of gastric trichobezoar crossing the pylorus and extending throughout the bowel. The case of a 22-year-old Peruvian woman is reported. This is the thirteenth patient with Rapunzel syndrome reported in the literature. The epidemiology, clinical manifestations, diagnosis and treatment are briefly reviewed.

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Composting of fish processing wastes and biosolids with wood by-products and yard trimmings was conducted during the summer of 1996 and winter of 1997 in NW Patagonia using: (i) static piles for fish offal and (ii) turning piles for biosolids. Fish offal was mixed with sawdust + wood shavings (FOC) at 3:1 ratio by weight and biosolids with wood shavings (BCw) and yard trimmings (BCt) at 1:1 ratio by volume. Samples were taken at six dates during the composting period and analyzed to determine the factors that predict compost maturity. Composting of biosolids was affected by the type of bulking agent during winter. Thermophilic temperatures > or = 55 degrees C were sustained long enough to satisfy the USEPA requirements for processes to further reduce pathogens (PFRP) in FOC and BCt, and for processes to significantly reduce pathogens (PSRP) in summer BCw, while in winter BCw temperatures were lower than those recommended for effective pathogen reduction. However, coliform fecal content in all BC treatments was less than 10 most probable number (MPN) g(-1) dry sample at the end of the process. The ratio of water soluble carbon (WSC) to total nitrogen (TN) appeared to be a more adequate index to predict compost maturity than the ratio of total organic carbon to nitrogen.

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In studies conducted in patients undergoing cardiac catheterizations, some hemodynamic changes were observed after the acute sublingual administration of the angiotensin converting enzyme inhibitors (ACEI) captopril, enalapril, and lisinopril. These changes consisted of an increase in pulmonary artery pressure, pulmonary vascular resistance (PVR) and induction of hypoxia. The pressure changes were transitory and disappeared after 25 min. The possible mechanisms involved in these changes may relate to interactions of the ACEI with peripheral receptor systems for hormones and neurotransmitters. We have thus undertaken the task of evaluating the potential effect of ACEI on biological receptor molecules. We have begun with studies on muscarinic receptors, and the recently characterized neuropeptide Y (NPY) receptors of endothelial cells. Equilibrium binding assays with 3H-QNB have been conducted for muscarinic receptors using rat brain synaptosomes, due to its expression of multiple muscarinic receptors subtypes. In addition 125BH-NPY binding assays were conducted on intact adrenal medullary endothelial cells. Enalapril and captopril, 10(-7) to 10(-3) M, were not able to produce significant inhibition of either muscarinic or NPY receptor probes. The paradoxical changes elicited by sublingual ACEI seems not to involve interaction with muscarinic or NPY receptors

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Amiloride (AM) is a well known potassium sparing diuretic. The effects of AM at the cellular level include blockade of Na+/H+ exchange in several tissues and inhibition of passive sodium flux in epithelial cells. In this study we have explored the interactions of amiloride with muscarinic receptors, using isolated rat tracheal rings and compared its effects to those of the muscarinic receptor subtype-selective antagonist pirenzepine (PZ). The results obtained demonstrate the ability of AM (100 uM to 1mM) to inhibit the ACh induced rat tracheall contractions. The inhibition resulted in the reduction of the Emax values of ACh in this preparation, and the apparent Ki for AM was of 478 uM. This effect was also observed in a sodium-free choline medium, indicating that it is independent from sodium transport mechanisms sensitive to AM. In contrast to AM, PZ displayed a surmountable type of antagonism with a pA2 value of 6.52. The results demonstrate a differential antagonism by AM and PZ of the muscarinic receptors present in the smooth muscle of the rat trachea

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An equilibrium kinetics model is proposed to described some of the enzymatic properties of the cyclic GMP-stimulated phosphodiesterase activity associated with brain clathrin coated vesicles. The model assumes the presence of pharmacologically distinct regultory and catalytic domains in the enzyme. The model contemplates that random fashion occupancy of the regulatory site by the substrate, cyclic GMP, induces a conformational change which leads to the generation of a actived catalytic state. Therefore, cyclic GMP is a positive allosteric modulator of the coated vesicle enzyme. Experimental data revealed that occupancy or activation of the regulatory site was not essential for catalysis to occur since hydrolysis occured after loss (200%) of the activation by cyclic GMP. This constitutes an example of non-essential substrate activation. Analysis of this PDE following activation by cGMP and after loss of the regulation, activation capacity of the enzyme allows the calculation of the various kinetic parameters inherent in the model

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Los ensayos recogidos en este volumen surgían como resultado de un seminario organizado en torno al documento que proporciona el título Mestizaje:

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