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1.
JAMA ; 331(8): 665-674, 2024 02 27.
Artículo en Inglés | MEDLINE | ID: mdl-38245889

RESUMEN

Importance: Sepsis is a leading cause of death among children worldwide. Current pediatric-specific criteria for sepsis were published in 2005 based on expert opinion. In 2016, the Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3) defined sepsis as life-threatening organ dysfunction caused by a dysregulated host response to infection, but it excluded children. Objective: To update and evaluate criteria for sepsis and septic shock in children. Evidence Review: The Society of Critical Care Medicine (SCCM) convened a task force of 35 pediatric experts in critical care, emergency medicine, infectious diseases, general pediatrics, nursing, public health, and neonatology from 6 continents. Using evidence from an international survey, systematic review and meta-analysis, and a new organ dysfunction score developed based on more than 3 million electronic health record encounters from 10 sites on 4 continents, a modified Delphi consensus process was employed to develop criteria. Findings: Based on survey data, most pediatric clinicians used sepsis to refer to infection with life-threatening organ dysfunction, which differed from prior pediatric sepsis criteria that used systemic inflammatory response syndrome (SIRS) criteria, which have poor predictive properties, and included the redundant term, severe sepsis. The SCCM task force recommends that sepsis in children be identified by a Phoenix Sepsis Score of at least 2 points in children with suspected infection, which indicates potentially life-threatening dysfunction of the respiratory, cardiovascular, coagulation, and/or neurological systems. Children with a Phoenix Sepsis Score of at least 2 points had in-hospital mortality of 7.1% in higher-resource settings and 28.5% in lower-resource settings, more than 8 times that of children with suspected infection not meeting these criteria. Mortality was higher in children who had organ dysfunction in at least 1 of 4-respiratory, cardiovascular, coagulation, and/or neurological-organ systems that was not the primary site of infection. Septic shock was defined as children with sepsis who had cardiovascular dysfunction, indicated by at least 1 cardiovascular point in the Phoenix Sepsis Score, which included severe hypotension for age, blood lactate exceeding 5 mmol/L, or need for vasoactive medication. Children with septic shock had an in-hospital mortality rate of 10.8% and 33.5% in higher- and lower-resource settings, respectively. Conclusions and Relevance: The Phoenix sepsis criteria for sepsis and septic shock in children were derived and validated by the international SCCM Pediatric Sepsis Definition Task Force using a large international database and survey, systematic review and meta-analysis, and modified Delphi consensus approach. A Phoenix Sepsis Score of at least 2 identified potentially life-threatening organ dysfunction in children younger than 18 years with infection, and its use has the potential to improve clinical care, epidemiological assessment, and research in pediatric sepsis and septic shock around the world.


Asunto(s)
Sepsis , Choque Séptico , Humanos , Niño , Choque Séptico/mortalidad , Insuficiencia Multiorgánica/diagnóstico , Insuficiencia Multiorgánica/etiología , Consenso , Sepsis/mortalidad , Síndrome de Respuesta Inflamatoria Sistémica/diagnóstico , Puntuaciones en la Disfunción de Órganos
2.
JAMA ; 331(8): 675-686, 2024 02 27.
Artículo en Inglés | MEDLINE | ID: mdl-38245897

RESUMEN

Importance: The Society of Critical Care Medicine Pediatric Sepsis Definition Task Force sought to develop and validate new clinical criteria for pediatric sepsis and septic shock using measures of organ dysfunction through a data-driven approach. Objective: To derive and validate novel criteria for pediatric sepsis and septic shock across differently resourced settings. Design, Setting, and Participants: Multicenter, international, retrospective cohort study in 10 health systems in the US, Colombia, Bangladesh, China, and Kenya, 3 of which were used as external validation sites. Data were collected from emergency and inpatient encounters for children (aged <18 years) from 2010 to 2019: 3 049 699 in the development (including derivation and internal validation) set and 581 317 in the external validation set. Exposure: Stacked regression models to predict mortality in children with suspected infection were derived and validated using the best-performing organ dysfunction subscores from 8 existing scores. The final model was then translated into an integer-based score used to establish binary criteria for sepsis and septic shock. Main Outcomes and Measures: The primary outcome for all analyses was in-hospital mortality. Model- and integer-based score performance measures included the area under the precision recall curve (AUPRC; primary) and area under the receiver operating characteristic curve (AUROC; secondary). For binary criteria, primary performance measures were positive predictive value and sensitivity. Results: Among the 172 984 children with suspected infection in the first 24 hours (development set; 1.2% mortality), a 4-organ-system model performed best. The integer version of that model, the Phoenix Sepsis Score, had AUPRCs of 0.23 to 0.38 (95% CI range, 0.20-0.39) and AUROCs of 0.71 to 0.92 (95% CI range, 0.70-0.92) to predict mortality in the validation sets. Using a Phoenix Sepsis Score of 2 points or higher in children with suspected infection as criteria for sepsis and sepsis plus 1 or more cardiovascular point as criteria for septic shock resulted in a higher positive predictive value and higher or similar sensitivity compared with the 2005 International Pediatric Sepsis Consensus Conference (IPSCC) criteria across differently resourced settings. Conclusions and Relevance: The novel Phoenix sepsis criteria, which were derived and validated using data from higher- and lower-resource settings, had improved performance for the diagnosis of pediatric sepsis and septic shock compared with the existing IPSCC criteria.


Asunto(s)
Sepsis , Choque Séptico , Humanos , Niño , Choque Séptico/mortalidad , Insuficiencia Multiorgánica , Estudios Retrospectivos , Puntuaciones en la Disfunción de Órganos , Sepsis/complicaciones , Mortalidad Hospitalaria
3.
Antimicrob Agents Chemother ; 67(5): e0013223, 2023 05 17.
Artículo en Inglés | MEDLINE | ID: mdl-37039666

RESUMEN

Trypanosoma cruzi naturally infects a broad range of mammalian species and frequently results in the pathology that has been most extensively characterized in human Chagas disease. Currently employed treatment regimens fail to achieve parasitological cure of T. cruzi infection in the majority of cases. In this study, we have extended our previous investigations of more effective, higher dose, intermittent administration protocols using the FDA-approved drug benznidazole (BNZ), in experimentally infected mice and in naturally infected dogs and nonhuman primates (NHP). Collectively, these studies demonstrate that twice-weekly administration of BNZ for more than 4 months at doses that are ~2.5-fold that of previously used daily dosing protocols, provided the best chance to obtain parasitological cure. Dosing less frequently or for shorter time periods was less dependable in all species. Prior treatment using an ineffective dosing regimen in NHPs did not prevent the attainment of parasitological cure with an intensified BNZ dosing protocol. Furthermore, parasites isolated after a failed BNZ treatment showed nearly identical susceptibility to BNZ as those obtained prior to treatment, confirming the low risk of induction of drug resistance with BNZ and the ability to adjust the treatment protocol when an initial regimen fails. These results provide guidance for the use of BNZ as an effective treatment for T. cruzi infection and encourage its wider use, minimally in high value dogs and at-risk NHP, but also potentially in humans, until better options are available.


Asunto(s)
Enfermedad de Chagas , Nitroimidazoles , Tripanocidas , Trypanosoma cruzi , Ratones , Perros , Humanos , Animales , Tripanocidas/uso terapéutico , Tripanocidas/farmacología , Enfermedad de Chagas/tratamiento farmacológico , Enfermedad de Chagas/parasitología , Nitroimidazoles/uso terapéutico , Nitroimidazoles/farmacología , Protocolos Clínicos , Primates , Mamíferos
4.
J Intensive Care Med ; 37(6): 753-763, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-34812664

RESUMEN

Objective: The aim of this study was to develop evidence-based recommendations for the diagnosis and treatment of sepsis in children in low- and middle-income countries (LMICs), more specifically in Latin America. Design: A panel was formed consisting of 27 experts with experience in the treatment of pediatric sepsis and two methodologists working in Latin American countries. The experts were organized into 10 nominal groups, each coordinated by a member. Methods: A formal consensus was formed based on the modified Delphi method, combining the opinions of nominal groups of experts with the interpretation of available scientific evidence, in a systematic process of consolidating a body of recommendations. The systematic search was performed by a specialized librarian and included specific algorithms for the Cochrane Specialized Register, PubMed, Lilacs, and Scopus, as well as for OpenGrey databases for grey literature. The GRADEpro GDT guide was used to classify each of the selected articles. Special emphasis was placed on search engines that included original research conducted in LMICs. Studies in English, Spanish, and Portuguese were covered. Through virtual meetings held between February 2020 and February 2021, the entire group of experts reviewed the recommendations and suggestions. Result: At the end of the 12 months of work, the consensus provided 62 recommendations for the diagnosis and treatment of pediatric sepsis in LMICs. Overall, 60 were strong recommendations, although 56 of these had a low level of evidence. Conclusions: These are the first consensus recommendations for the diagnosis and management of pediatric sepsis focused on LMICs, more specifically in Latin American countries. The consensus shows that, in these regions, where the burden of pediatric sepsis is greater than in high-income countries, there is little high-level evidence. Despite the limitations, this consensus is an important step forward for the diagnosis and treatment of pediatric sepsis in Latin America.


Asunto(s)
Sepsis , Niño , Consenso , Cuidados Críticos/métodos , Humanos , América Latina , Sepsis/diagnóstico , Sepsis/terapia
5.
Addict Biol ; 26(6): e13072, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34137121

RESUMEN

Previous investigations have used global graph theory measures in order to disentangle the complexity of the neural reorganizations occurring in cocaine use disorder (CUD). However, how these global topological alterations map into individual brain network areas remains unknown. In this study, we used resting state functional magnetic resonance imaging (fMRI) data to investigate node-level topological dysfunctions in CUD. The sample was composed of 32 individuals with CUD and 32 healthy controls, matched in age, years of education and intellectual functioning. Graph theory measures of optimal connectivity distance, node strength, nodal efficiency and clustering coefficient were estimated in each participant using voxel-wise functional connectivity connectomes. CUD individuals as compared with healthy controls showed higher optimal connectivity distances in ventral striatum, insula, cerebellum, temporal cortex, lateral orbitofrontal cortex, middle frontal cortex and left hippocampus. Furthermore, clinical measures quantifying severity of dependence were positively related with optimal connectivity distances in the right rolandic operculum and the right lateral orbitofrontal cortex, whereas length of abstinence was negatively associated with optimal connectivity distances in the right temporal pole and the left insula. Our results reveal a topological distancing of cognitive and affective related areas in addiction, suggesting an overall reduction in the communication capacity of these regions.


Asunto(s)
Encéfalo/patología , Trastornos Relacionados con Cocaína/patología , Adulto , Encéfalo/diagnóstico por imagen , Mapeo Encefálico , Trastornos Relacionados con Cocaína/diagnóstico por imagen , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Gravedad del Paciente
6.
BMC Pediatr ; 21(1): 516, 2021 11 18.
Artículo en Inglés | MEDLINE | ID: mdl-34794410

RESUMEN

BACKGROUND: The clinical presentation and severity of Multisystem Inflammatory Syndrome in Children associated with COVID-19 (MIS-C) is widespread and presents a very low mortality rate in high-income countries. This research describes the clinical characteristics of MIS-C in critically ill children in middle-income countries and the factors associated with the rate of mortality and patients with critical outcomes. METHODS: An observational cohort study was conducted in 14 pediatric intensive care units (PICUs) in Colombia between April 01, 2020, and January 31, 2021. Patient age ranged between one month and 18 years, and each patient met the requirements set forth by the World Health Organization (WHO) for MIS-C. RESULTS: There were seventy-eight children in this study. The median age was seven years (IQR 1-11), 18 % (14/78) were under one year old, and 56 % were male. 35 % of patients (29/78) were obese or overweight. The PICU stay per individual was six days (IQR 4-7), and 100 % had a fever upon arrival to the clinic lasting at least five days (IQR 3.7-6). 70 % (55/78) of patients had diarrhea, and 87 % (68/78) had shock or systolic myocardial dysfunction (78 %). Coronary aneurysms were found in 35 % (27/78) of cases, and pericardial effusion was found in 36 %. When compared to existing data in high-income countries, there was a higher mortality rate observed (9 % vs. 1.8 %; p=0.001). When assessing the group of patients that did not survive, a higher frequency of ferritin levels was found, above 500 ngr/mL (100 % vs. 45 %; p=0.012), as well as more cardiovascular complications (100 % vs. 54 %; p = 0.019) when compared to the group that survived. The main treatments received were immunoglobulin (91 %), vasoactive support (76 %), steroids (70.5 %) and antiplatelets (44 %). CONCLUSIONS: Multisystem Inflammatory Syndrome in Children due to SARS-CoV-2 in critically ill children living in a middle-income country has some clinical, laboratory, and echocardiographic characteristics similar to those described in high-income countries. The observed inflammatory response and cardiovascular involvement were conditions that, added to the later presentation, may explain the higher mortality seen in these children.


Asunto(s)
COVID-19 , COVID-19/complicaciones , Niño , Preescolar , Enfermedad Crítica , Humanos , Lactante , Masculino , SARS-CoV-2 , Síndrome de Respuesta Inflamatoria Sistémica
7.
Pediatr Emerg Care ; 37(1): 44-47, 2021 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-33181794

RESUMEN

ABSTRACT: Pediatric inflammatory multisystem syndrome temporally associated with severe acute respiratory syndrome coronavirus 2 (PIMS-TS) is infrequent, but children might present as a life-threatening disease. In a systematic quantitative review, we analyzed 11 studies of PIMS-TS, including 468 children reported before July 1, 2020. We found a myriad of clinical features, but we were able to describe common characteristics: previously healthy school-aged children, persistent fever and gastrointestinal symptoms, lymphopenia, and high inflammatory markers. Clinical syndromes such as myocarditis and Kawasaki disease were present in only one third of cases each one. Pediatric intensive care unit admission was frequent, although length of stay was less than 1 week, and mortality was low. Most patients received immunoglobulin or steroids, although the level of evidence for that treatment is low. The PIMS-ST was recently described, and the detailed quantitative pooled data will increase clinicians' awareness, improve diagnosis, and promptly start treatment. This analysis also highlights the necessity of future collaborative studies, given the heterogeneous nature of the PIMS-TS.


Asunto(s)
COVID-19/complicaciones , SARS-CoV-2 , Síndrome de Respuesta Inflamatoria Sistémica/etiología , Corticoesteroides/uso terapéutico , Antibacterianos/uso terapéutico , Anticoagulantes/uso terapéutico , COVID-19/epidemiología , COVID-19/etiología , COVID-19/terapia , Niño , Terapia Combinada , Femenino , Humanos , Inmunoglobulinas Intravenosas/uso terapéutico , Inmunosupresores/uso terapéutico , Unidades de Cuidado Intensivo Pediátrico/estadística & datos numéricos , Tiempo de Internación/estadística & datos numéricos , Masculino , Síndrome Mucocutáneo Linfonodular/epidemiología , Síndrome Mucocutáneo Linfonodular/etiología , Miocarditis/epidemiología , Miocarditis/etiología , Síndrome de Respuesta Inflamatoria Sistémica/tratamiento farmacológico , Síndrome de Respuesta Inflamatoria Sistémica/epidemiología , Tratamiento Farmacológico de COVID-19
8.
Addict Biol ; 25(4): e12820, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-31436010

RESUMEN

Cocaine addiction is characterized by alterations in motivational and cognitive processes involved in goal-directed behavior. Recent studies have shown that addictive behaviors can be attributed to alterations in the activity of large functional networks. The aim of this study was to investigate how cocaine addiction affected the left frontoparietal network during goal-directed behavior in a stop-signal task (SST) with reward contingencies by correct task performance. Twenty-eight healthy controls (HC) and 30 abstinent cocaine-dependent patients (ACD) performed SST with monetary reward contingencies while undergoing a functional magnetic resonance imaging scan. The results showed that the left frontoparietal network (FPN) displayed an effect of cocaine addiction depending on reward contingencies rather than inhibition accuracy; and, second, we observed a negative correlation between dependence severity and the modulation of the left FPN network by the monetary reward in ACD. These findings highlight the role of the left FPN in the motivational effects of cocaine dependence.


Asunto(s)
Trastornos Relacionados con Cocaína/diagnóstico por imagen , Cognición , Lóbulo Frontal/diagnóstico por imagen , Motivación , Lóbulo Parietal/diagnóstico por imagen , Adulto , Estudios de Casos y Controles , Trastornos Relacionados con Cocaína/fisiopatología , Trastornos Relacionados con Cocaína/psicología , Femenino , Lóbulo Frontal/fisiopatología , Neuroimagen Funcional , Humanos , Inhibición Psicológica , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Vías Nerviosas/diagnóstico por imagen , Vías Nerviosas/fisiopatología , Lóbulo Parietal/fisiopatología , Recompensa
9.
Rev Chil Pediatr ; 91(2): 216-225, 2020 Apr.
Artículo en Inglés, Español | MEDLINE | ID: mdl-32730540

RESUMEN

The objective of this study was to describe the management of infants with acute bronchiolitis admit ted to 20 pediatric intensive care units (PICU) members of LARed in 5 Latin American countries. Pa tients and Method: Retrospective, multicenter, observational study of data from the Latin American Registry of Acute Pediatric Respiratory Failure. We included children under 2 years of age admitted to the PICU due to community-based acute bronchiolitis between May and September 2017. Demo graphic and clinical data, respiratory support, therapies used, and clinical results were collected. A subgroup analysis was carried out according to geographical location (Atlantic v/s Pacific), type of insurance (Public v/s Private), and Academic v/s non-Academic centers. Results: 1,155 patients were included in the registry which present acute respiratory failure and 6 were excluded due to the lack of information in their record form. Out of the 1,147 patients, 908 were under 2 years of age, and out of those, 467 (51.4%) were diagnosed with acute bronchiolitis, which was the main cause of admission to the PICU due to acute respiratory failure. The demographic and severity characteristics among the centers were similar. The most frequent maximum ventilatory support was the high-flow nasal can nula (47%), followed by non-invasive ventilation (26%) and invasive mechanical ventilation (17%), with a wide coefficient of variation (CV) between centers. There was a great dispersion in the use of treatments, where the use of bronchodilators, antibiotics, and corticosteroids, representing a CV up to 400%. There were significant differences in subgroup analysis regarding respiratory support and treatments used. One patient of this cohort passed away. Conclusion: we detected wide variability in respiratory support and treatments among Latin American PICUs. This variability was not explained by demographic or clinical differences. The heterogeneity of treatments should encourage collabora tive initiatives to reduce the gap between scientific evidence and practice.


Asunto(s)
Bronquiolitis/terapia , Cuidados Críticos/estadística & datos numéricos , Adhesión a Directriz/estadística & datos numéricos , Disparidades en Atención de Salud/estadística & datos numéricos , Unidades de Cuidado Intensivo Pediátrico/estadística & datos numéricos , Pautas de la Práctica en Medicina/estadística & datos numéricos , Enfermedad Aguda , Bronquiolitis/diagnóstico , Cuidados Críticos/métodos , Femenino , Humanos , Lactante , Recién Nacido , América Latina , Masculino , Guías de Práctica Clínica como Asunto , Sistema de Registros , Estudios Retrospectivos
10.
Glycobiology ; 29(4): 280-284, 2019 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-30649355

RESUMEN

Trypanosoma cruzi is a protozoan parasite that causes Chagas disease, a debilitating condition that affects over 10 million humans in the American continents. In addition to its traditional mode of human entry via the "kissing bug" in endemic areas, the infection can also be spread in non-endemic countries through blood transfusion, organ transplantation, eating food contaminated with the parasites, and from mother to fetus. Previous NMR-based studies established that the parasite expresses a variety of strain-specific and developmentally-regulated O-glycans that may contribute to virulence. In this report, we describe five synthetic O-glycan analytical standards and show their potential to enable a more facile analysis of native O-glycan isomers based on mass spectrometry.


Asunto(s)
Isótopos de Carbono/análisis , Espectrometría de Masas/métodos , Espectrometría de Masas/normas , Polisacáridos/análisis , Polisacáridos/química , Trypanosoma cruzi/química , Conformación de Carbohidratos , Isótopos de Carbono/química
11.
Pediatr Crit Care Med ; 19(3): e152-e156, 2018 03.
Artículo en Inglés | MEDLINE | ID: mdl-29252866

RESUMEN

OBJECTIVES: To develop a Latin American Consensus about Pediatric Cardiopulmonary Resuscitation. To clarify, reinforce, and adapt some specific recommendations for pediatric patients and to stimulate the implementation of these recommendations in clinical practice. DESIGN: Expert consensus recommendations with Delphi methodology. SETTING: Latin American countries. SUBJECTS: Experts in pediatric cardiopulmonary resuscitation from 19 Latin American countries. INTERVENTIONS: Delphi methodology for expert consensus. MEASUREMENTS AND MAIN RESULTS: The goal was to reach consensus with all the participating experts for every recommendation. An agreement of at least 80% of the participating experts had to exist in order to deliver a recommendation. Two Delphi voting rounds were sent out electronically. The experts were asked to score between 1 and 9 their level of agreement for each recommendation. The score was then classified into three groups: strong agreement (score 7-9), moderate agreement (score 4-6), and disagreement (score 1-3). Nineteen experts from 19 countries participated in both voting rounds and in the whole process of drafting the recommendations. Sixteen recommendations about organization of cardiopulmonary resuscitation, prevention, basic resuscitation, advanced resuscitation, and postresuscitation measures were approved. Ten of them had a consensus of 100%. Four of them were agreed by all the participants except one (94.7% consensus). One recommendation was agreed by all except two experts (89.4%), and finally, one was agreed by all except three experts (84.2%). All the recommendations reached a level of agreement. CONCLUSIONS: This consensus adapts 16 international recommendations to Latin America in order to improve the practice of cardiopulmonary resuscitation in children. Studies should be conducted to analyze the effectiveness of the implementation of these recommendations.


Asunto(s)
Reanimación Cardiopulmonar/métodos , Cuidados Críticos/métodos , Consenso , Técnica Delphi , Humanos , América Latina , Guías de Práctica Clínica como Asunto , Sociedades Médicas
12.
Exp Parasitol ; 189: 19-27, 2018 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-29726395

RESUMEN

Combination therapies based on the available drugs have been proposed as promising therapeutic alternatives for many diseases. Clomipramine (CLO) has been found to modify the evolution of the experimental infection. The objective of this study was to evaluate the combined effect of benznidazole (BZ) and clomipramine (CLO) against different life-stages of Trypanosoma cruzi in vitro and their efficacy in a murine model. Life-stages of T. cruzi, BZ-partially-resistant (Y) strain, were incubated with BZ and CLO and isobolograms and combination index (CI) were obtained. Swiss mice were infected with trypomastigotes and different treatment schedules were performed, each of which consisted of 30 consecutive daily doses. Treatment efficacy was evaluated by comparing parasitemia, qPCR, survival and histological analysis. These results were analyzed using multivariate analysis to determine the combined effect of the drugs in vivo. CLO + BZ showed synergistic activity in vitro against the clinically relevant life-stages of T. cruzi. The most susceptible forms were the intracellular amastigotes (CI: 0.20), followed by trypomastigotes (CI: 0.60), with no toxicity upon mammalian cells. The combination of both drugs CLO (1.25 mg/kg) and BZ (6.25 mg/kg), in vivo, significantly diminished the parasitic load in blood and the mortality rate. CLO + BZ presented a similar inflammatory response in cardiac and skeletal muscle (amount of inflammatory cells) to BZ (6.25 mg/kg). Finally, the results from the principal component analysis reaffirmed that both drugs administered in combination presented higher activity compared with the individual administration in the acute experimental model.


Asunto(s)
Enfermedad de Chagas/tratamiento farmacológico , Clomipramina/farmacología , Nitroimidazoles/farmacología , Tripanocidas/farmacología , Trypanosoma cruzi/efectos de los fármacos , Animales , Clomipramina/uso terapéutico , Relación Dosis-Respuesta a Droga , Sinergismo Farmacológico , Quimioterapia Combinada , Femenino , Concentración 50 Inhibidora , Masculino , Ratones , Análisis Multivariante , Músculo Esquelético/parasitología , Músculo Esquelético/patología , Miocardio/patología , Nitroimidazoles/uso terapéutico , Parasitemia/tratamiento farmacológico , Análisis de Componente Principal , Reacción en Cadena en Tiempo Real de la Polimerasa , Tripanocidas/uso terapéutico
13.
Bioinformatics ; 32(12): 1805-13, 2016 06 15.
Artículo en Inglés | MEDLINE | ID: mdl-27153569

RESUMEN

MOTIVATION: Hemeproteins have many diverse functions that largely depend on the rate at which they uptake or release small ligands, like oxygen. These proteins have been extensively studied using either simulations or experiments, albeit only qualitatively and one or two proteins at a time. RESULTS: We present a physical-chemical model, which uses data obtained exclusively from computer simulations, to describe the uptake and release of oxygen in a family of hemeproteins, called truncated hemoglobins (trHbs). Through a rigorous statistical analysis we demonstrate that our model successfully recaptures all the reported experimental oxygen association and dissociation kinetic rate constants, thus allowing us to establish the key factors that determine the rates at which these hemeproteins uptake and release oxygen. We found that internal tunnels as well as the distal site water molecules control ligand uptake, whereas oxygen stabilization by distal site residues controls ligand release. Because these rates largely determine the functions of these hemeproteins, these approaches will also be important tools in characterizing the trHbs members with unknown functions. CONTACT: lboechi@ic.fcen.uba.ar SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.


Asunto(s)
Hemoproteínas/metabolismo , Cinética , Ligandos , Oxígeno , Hemoglobinas Truncadas
14.
PLoS Comput Biol ; 12(1): e1004701, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-26788940

RESUMEN

Predicting function from sequence is an important goal in current biological research, and although, broad functional assignment is possible when a protein is assigned to a family, predicting functional specificity with accuracy is not straightforward. If function is provided by key structural properties and the relevant properties can be computed using the sequence as the starting point, it should in principle be possible to predict function in detail. The truncated hemoglobin family presents an interesting benchmark study due to their ubiquity, sequence diversity in the context of a conserved fold and the number of characterized members. Their functions are tightly related to O2 affinity and reactivity, as determined by the association and dissociation rate constants, both of which can be predicted and analyzed using in-silico based tools. In the present work we have applied a strategy, which combines homology modeling with molecular based energy calculations, to predict and analyze function of all known truncated hemoglobins in an evolutionary context. Our results show that truncated hemoglobins present conserved family features, but that its structure is flexible enough to allow the switch from high to low affinity in a few evolutionary steps. Most proteins display moderate to high oxygen affinities and multiple ligand migration paths, which, besides some minor trends, show heterogeneous distributions throughout the phylogenetic tree, again suggesting fast functional adaptation. Our data not only deepens our comprehension of the structural basis governing ligand affinity, but they also highlight some interesting functional evolutionary trends.


Asunto(s)
Hemoglobinas Truncadas , Secuencia de Aminoácidos , Biología Computacional , Evolución Molecular , Modelos Lineales , Modelos Moleculares , Datos de Secuencia Molecular , Oxígeno/metabolismo , Filogenia , Alineación de Secuencia , Hemoglobinas Truncadas/química , Hemoglobinas Truncadas/genética , Hemoglobinas Truncadas/fisiología
15.
Addict Biol ; 22(2): 479-489, 2017 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26610386

RESUMEN

Cocaine addiction is characterized by alterations in motivational and cognitive processes. Recent studies have shown that some alterations present in cocaine users may be related to the activity of large functional networks. The aim of this study was to investigate how these functional networks are modulated by non-drug rewarding stimuli in cocaine-dependent individuals. Twenty abstinent cocaine-dependent and 21 healthy matched male controls viewed erotic and neutral pictures while undergoing a functional magnetic resonance imaging scan. Group independent component analysis was then performed in order to investigate how functional networks were modulated by reward in cocaine addicts. The results showed that cocaine addicts, compared with healthy controls, displayed diminished modulation of the left frontoparietal network in response to erotic pictures, specifically when they were unpredicted. Additionally, a positive correlation between the length of cocaine abstinence and the modulation of the left frontoparietal network by unpredicted erotic images was found. In agreement with current addiction models, our results suggest that cocaine addiction contributes to reduce sensitivity to rewarding stimuli and that abstinence may mitigate this effect.


Asunto(s)
Trastornos Relacionados con Cocaína/diagnóstico por imagen , Lóbulo Frontal/diagnóstico por imagen , Lóbulo Parietal/diagnóstico por imagen , Recompensa , Adulto , Encéfalo/diagnóstico por imagen , Encéfalo/fisiopatología , Estudios de Casos y Controles , Trastornos Relacionados con Cocaína/fisiopatología , Lóbulo Frontal/fisiopatología , Neuroimagen Funcional , Humanos , Imagen por Resonancia Magnética , Masculino , Vías Nerviosas/diagnóstico por imagen , Vías Nerviosas/fisiopatología , Lóbulo Parietal/fisiopatología
16.
Infect Immun ; 84(9): 2627-38, 2016 09.
Artículo en Inglés | MEDLINE | ID: mdl-27354447

RESUMEN

Trypanosoma cruzi infection drives the expansion of remarkably focused CD8(+) T cell responses targeting epitopes encoded by variant trans-sialidase (TS) genes. Infection of C57BL/6 mice with T. cruzi results in up to 40% of all CD8(+) T cells committed to recognition of the dominant TSKB20 and subdominant TSKB18 TS epitopes. However, despite this enormous response, these mice fail to clear T. cruzi infection and subsequently develop chronic disease. One possible reason for the failure to cure T. cruzi infection is that immunodomination by these TS-specific T cells may interfere with alternative CD8(+) T cell responses more capable of complete parasite elimination. To address this possibility, we created transgenic mice that are centrally tolerant to these immunodominant epitopes. Mice expressing TSKB20, TSKB18, or both epitopes controlled T. cruzi infection and developed effector CD8(+) T cells that maintained an activated phenotype. Memory CD8(+) T cells from drug-cured TSKB-transgenic mice rapidly responded to secondary T. cruzi infection. In the absence of the response to TSKB20 and TSKB18, immunodominance did not shift to other known subdominant epitopes despite the capacity of these mice to expand epitope-specific T cells specific for the model antigen ovalbumin expressed by engineered parasites. Thus, CD8(+) T cell responses tightly and robustly focused on a few epitopes within variant TS antigens appear to neither contribute to, nor detract from, the ability to control T. cruzi infection. These data also indicate that the relative position of an epitope within a CD8(+) immunodominance hierarchy does not predict its importance in pathogen control.


Asunto(s)
Linfocitos T CD8-positivos/inmunología , Enfermedad de Chagas/inmunología , Glicoproteínas/inmunología , Inmunidad/inmunología , Epítopos Inmunodominantes/inmunología , Neuraminidasa/inmunología , Trypanosoma cruzi/inmunología , Animales , Enfermedad de Chagas/parasitología , Epítopos de Linfocito T/inmunología , Ratones , Ratones Endogámicos C57BL
17.
Neuroimage ; 124(Pt A): 287-299, 2016 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-26343318

RESUMEN

A "disinhibited" cognitive profile has been proposed for individuals with high reward sensitivity, characterized by increased engagement in goal-directed responses and reduced processing of negative or unexpected cues, which impairs adequate behavioral regulation after feedback in these individuals. This pattern is manifested through deficits in inhibitory control and/or increases in RT variability. In the present work, we aimed to test whether this profile is associated with the activity of functional networks during a stop-signal task using independent component analysis (ICA). Sixty-one participants underwent fMRI while performing a stop-signal task, during which a manual response had to be inhibited. ICA was used to mainly replicate the functional networks involved in the task (Zhang and Li, 2012): two motor networks involved in the go response, the left and right fronto-parietal networks for stopping, a midline error-processing network, and the default-mode network (DMN), which was further subdivided into its anterior and posterior parts. Reward sensitivity was mainly associated with greater activity of motor networks, reduced activity in the midline network during correct stop trials and, behaviorally, increased RT variability. All these variables explained 36% of variance of the SR scores. This pattern of associations suggests that reward sensitivity involves greater motor engagement in the dominant response, more distractibility and reduced processing of salient or unexpected events, which may lead to disinhibited behavior.


Asunto(s)
Atención/fisiología , Encéfalo/fisiología , Individualidad , Inhibición Psicológica , Recompensa , Adolescente , Adulto , Mapeo Encefálico , Toma de Decisiones/fisiología , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Modelos Neurológicos , Vías Nerviosas/fisiología , Tiempo de Reacción , Adulto Joven
18.
Int J Exp Pathol ; 97(5): 397-407, 2016 10.
Artículo en Inglés | MEDLINE | ID: mdl-27921351

RESUMEN

Inositol hexakisphosphate (IP6) and inositol both regulate insulin secretion, but their combined use in the management of diabetes deserves investigation. The combined effects of IP6 and inositol supplementation were investigated in streptozotocin-induced type 2 diabetic rats. The following groups of rats were studied for 8 weeks: non-diabetic control, non-diabetic high-fat diet control, diabetic untreated, diabetic rats treated with the combination of IP6 and inositol (650 mg/kg bw) and diabetic rats treated with glibenclamide (10 mg/kg bw). High-fat diet and streptozotocin were used to induce type 2 diabetes mellitus in Sprague-Dawley rats. Body weight, blood glucose, glycated haemoglobin, insulin, serum leptin, HOMA-insulin resistance scores, intestinal amylase activity, serum and faecal lipids and food and fluid consumption were measured. Treatment with the combination significantly reduced blood glucose (306 ± 53 mg/dl) and insulin resistance score (1.93 ± 0.45) compared with diabetic controls (522 ± 24 mg/dl and 5.1 ± 0.69 respectively). Serum leptin (2.8 ± 0.6 ng/dl) and faecal triglycerides (108 ± 8 mg/dl) were significantly increased in rats treated with the combination compared with the diabetic control (1.8 ± 0.06 ng/dl and 86 ± 4 mg/dl). Serum triglyceride (47 ± 5.1 mg/dl), total cholesterol (98 ± 3.2 mg/dl) and food intake (26 ± 0.3 g) were significantly reduced by 45%, 25% and 25%, respectively, in rats treated with the combination compared with the diabetic control. Inositol and IP6 combined supplementation may be effective in the management of type 2 diabetes mellitus and related metabolic disorders by regulating some aspects of lipid and carbohydrate metabolism.


Asunto(s)
Diabetes Mellitus Experimental/tratamiento farmacológico , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Hipoglucemiantes/uso terapéutico , Inositol/uso terapéutico , Ácido Fítico/uso terapéutico , Amilasas/metabolismo , Animales , Glucemia/metabolismo , Peso Corporal/efectos de los fármacos , Diabetes Mellitus Experimental/sangre , Diabetes Mellitus Experimental/fisiopatología , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/fisiopatología , Suplementos Dietéticos , Ingestión de Líquidos/efectos de los fármacos , Ingestión de Líquidos/fisiología , Evaluación Preclínica de Medicamentos/métodos , Quimioterapia Combinada , Ingestión de Alimentos/efectos de los fármacos , Ingestión de Alimentos/fisiología , Heces/química , Hipoglucemiantes/farmacología , Inositol/farmacología , Intestinos/enzimología , Leptina/sangre , Metabolismo de los Lípidos/efectos de los fármacos , Lípidos/sangre , Masculino , Ácido Fítico/farmacología , Ratas Sprague-Dawley
19.
Am J Respir Crit Care Med ; 191(10): 1147-57, 2015 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-25734408

RESUMEN

RATIONALE: Limited data exist about the international burden of severe sepsis in critically ill children. OBJECTIVES: To characterize the global prevalence, therapies, and outcomes of severe sepsis in pediatric intensive care units to better inform interventional trials. METHODS: A point prevalence study was conducted on 5 days throughout 2013-2014 at 128 sites in 26 countries. Patients younger than 18 years of age with severe sepsis as defined by consensus criteria were included. Outcomes were severe sepsis point prevalence, therapies used, new or progressive multiorgan dysfunction, ventilator- and vasoactive-free days at Day 28, functional status, and mortality. MEASUREMENTS AND MAIN RESULTS: Of 6,925 patients screened, 569 had severe sepsis (prevalence, 8.2%; 95% confidence interval, 7.6-8.9%). The patients' median age was 3.0 (interquartile range [IQR], 0.7-11.0) years. The most frequent sites of infection were respiratory (40%) and bloodstream (19%). Common therapies included mechanical ventilation (74% of patients), vasoactive infusions (55%), and corticosteroids (45%). Hospital mortality was 25% and did not differ by age or between developed and resource-limited countries. Median ventilator-free days were 16 (IQR, 0-25), and vasoactive-free days were 23 (IQR, 12-28). Sixty-seven percent of patients had multiorgan dysfunction at sepsis recognition, with 30% subsequently developing new or progressive multiorgan dysfunction. Among survivors, 17% developed at least moderate disability. Sample sizes needed to detect a 5-10% absolute risk reduction in outcomes within interventional trials are estimated between 165 and 1,471 [corrected] patients per group. CONCLUSIONS: Pediatric severe sepsis remains a burdensome public health problem, with prevalence, morbidity, and mortality rates similar to those reported in critically ill adult populations. International clinical trials targeting children with severe sepsis are warranted.


Asunto(s)
Salud Global/estadística & datos numéricos , Insuficiencia Multiorgánica/epidemiología , Sepsis/epidemiología , Adolescente , Niño , Preescolar , Estudios Transversales , Bases de Datos Factuales , Mortalidad Hospitalaria , Humanos , Lactante , Recién Nacido , Unidades de Cuidado Intensivo Pediátrico/estadística & datos numéricos , Insuficiencia Multiorgánica/microbiología , Insuficiencia Multiorgánica/mortalidad , Evaluación de Procesos y Resultados en Atención de Salud/estadística & datos numéricos , Prevalencia , Estudios Prospectivos , Respiración Artificial/estadística & datos numéricos , Sepsis/microbiología , Sepsis/mortalidad
20.
Neural Plast ; 2016: 9504642, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-26998365

RESUMEN

The topic of investigating how mindfulness meditation training can have antidepressant effects via plastic changes in both resting state and meditation state brain activity is important in the rapidly emerging field of neuroplasticity. In the present study, we used a longitudinal design investigating resting state fMRI both before and after 40 days of meditation training in 13 novices. After training, we compared differences in network connectivity between rest and meditation using common resting state functional connectivity methods. Interregional methods were paired with local measures such as Regional Homogeneity. As expected, significant differences in functional connectivity both between states (rest versus meditation) and between time points (before versus after training) were observed. During meditation, the internal consistency in the precuneus and the temporoparietal junction increased, while the internal consistency of frontal brain regions decreased. A follow-up analysis of regional connectivity of the dorsal anterior cingulate cortex further revealed reduced connectivity with anterior insula during meditation. After meditation training, reduced resting state functional connectivity between the pregenual anterior cingulate and dorsal medical prefrontal cortex was observed. Most importantly, significantly reduced depression/anxiety scores were observed after training. Hence, these findings suggest that mindfulness meditation might be of therapeutic use by inducing plasticity related network changes altering the neuronal basis of affective disorders such as depression.


Asunto(s)
Ansiedad/fisiopatología , Encéfalo/fisiología , Depresión/fisiopatología , Atención Plena , Plasticidad Neuronal , Adulto , Mapeo Encefálico , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Vías Nerviosas/fisiología , Adulto Joven
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