RESUMEN
A 62-year-old received orthotopic liver transplantation. Three weeks later, thrombotic microangiopathy developed. Testing revealed thrombotic thrombocytopenic purpura (TTP) characterized by low ADAMTS13 (A Disintegrin-like Metallopeptidase with ThromboSpondin type 1 motif 13) activity and no inhibitor of ADAMTS13 protein. Retrospective attainment of donor records revealed a TTP diagnosis, presumably hereditary TTP (hTTP), as an ADAMTS13 protein inhibitor was not mentioned. As the grafted liver does not produce ADAMTS13 protein, the recipient now functionally has hTTP and will likely need plasma transfusions indefinitely. While hTTP is extremely rare, it should be considered a contraindication to liver donation outside of exceptional circumstances. If a potential liver donor has TTP listed on medical history, attempts should be made to determine whether it is autoimmune or hereditary. An accurate medical history is critical as it is the only reliable way to identify hTTP, as outside of acute exacerbations of TTP, donors with hTTP can have normal laboratory values, including normal hemoglobin, platelets, and renal function.
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Trasplante de Hígado , Púrpura Trombocitopénica Trombótica , Microangiopatías Trombóticas , Humanos , Persona de Mediana Edad , Púrpura Trombocitopénica Trombótica/diagnóstico , Proteína ADAMTS13 , Estudios RetrospectivosRESUMEN
Painful or threatening experiences trigger escape responses that are guided by nociceptive neuronal circuitry. Although some components of this circuitry are known and conserved across animals, how this circuitry is regulated at the genetic and developmental levels is mostly unknown. To escape noxious stimuli, such as parasitoid wasp attacks, Drosophila melanogaster larvae generate a curling and rolling response. Rover and sitter allelic variants of the Drosophila foraging (for) gene differ in parasitoid wasp susceptibility, suggesting a link between for and nociception. By optogenetically activating cells associated with each of for's promoters (pr1-pr4), we show that pr1 cells regulate larval escape behavior. In accordance with rover and sitter differences in parasitoid wasp susceptibility, we found that rovers have higher pr1 expression and increased sensitivity to nociception relative to sitters. The for null mutants display impaired responses to thermal nociception, which are rescued by restoring for expression in pr1 cells. Conversely, knockdown of for in pr1 cells phenocopies the for null mutant. To gain insight into the circuitry underlying this response, we used an intersectional approach and activity-dependent GFP reconstitution across synaptic partners (GRASP) to show that pr1 cells in the ventral nerve cord (VNC) are required for the nociceptive response, and that multidendritic sensory nociceptive neurons synapse onto pr1 neurons in the VNC. Finally, we show that activation of the pr1 circuit during development suppresses the escape response. Our data demonstrate a role of for in larval nociceptive behavior. This function is specific to for pr1 neurons in the VNC, guiding a developmentally plastic escape response circuit.
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Proteínas Quinasas Dependientes de GMP Cíclico/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/fisiología , Reacción de Fuga , Larva/crecimiento & desarrollo , Nociceptores/metabolismo , Animales , Proteínas Quinasas Dependientes de GMP Cíclico/genética , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Drosophila melanogaster/crecimiento & desarrollo , Calor , Larva/genética , Larva/fisiología , Plasticidad Neuronal , Nocicepción , Regiones Promotoras Genéticas , Avispas/fisiologíaRESUMEN
BACKGROUND: Malignancy-related ascites accounts for approximately 10% of causes of ascites. Our AIM was to characterize the ascites fluid and correlate clinical outcomes in those with extrahepatic malignancy and ascites. METHODS: 241 subjects with extrahepatic solid tumors and ascites were reviewed from 1/1/2000 to 12/31/2019, 119 without liver metastasis and 122 with liver metastasis. RESULTS: Ascites fluid consistent with peritoneal carcinomatosis (PC) was most common, 150/241 (62%), followed by fluid reflecting the presence of portal hypertension (PH), 69/241 (29%). 22/241 (9%) had low SAAG and low ascites fluid total protein, with evidence of PC on cytology and or imaging in 20/22. Lung cancer was the most common malignancy in subjects with ascites due to PC at 36/150 (24%), pancreatic cancer was the most common in subjects with ascites with features of PH at 16/69 (23%). Chemotherapy or immunotherapy alone was the most common management approach. Significantly higher 5-year, 3-year and 1-year mortality rate were noted in subjects with evidence of PC on cytology/imaging versus subjects with no evidence of PC, and in subjects with liver metastasis compared to subjects without liver metastasis. Subjects with pancreatic cancer and evidence of PC on cytology/imaging had higher 1 and 5-year mortality rates compared to subjects without PC. CONCLUSIONS: Ascites in solid tumor malignancy is most commonly due to PC. We also observed ascites fluid with characteristics of PH in 29% of subjects. Higher mortality rates in subjects with peritoneal carcinomatosis and liver metastasis were noted. These findings may help inform prognosis and treatment strategies.
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Hipertensión Portal , Neoplasias Hepáticas , Neoplasias Pancreáticas , Neoplasias Peritoneales , Ascitis/etiología , Líquido Ascítico/química , Humanos , Hipertensión Portal/complicaciones , Neoplasias Hepáticas/secundario , Neoplasias Pancreáticas/complicaciones , Neoplasias Peritoneales/secundario , Neoplasias PancreáticasRESUMEN
BACKGROUND & AIMS: Recently, international experts proposed redefining non-alcoholic fatty liver disease (NAFLD) as metabolic dysfunction-associated fatty liver disease (MAFLD), based on modified criteria. It is suspected that outcomes such as mortality may differ for these clinical entities. We studied the impact of MAFLD and NAFLD on all-cause and cause-specific mortality in US adults. METHODS: We analyzed data from 7,761 participants in the Third National Health and Nutrition Examination Survey and their linked mortality through 2015. NAFLD was diagnosed by ultrasonographic evidence of hepatic steatosis without other known liver diseases. MAFLD was defined based on the criteria proposed by an international expert panel. The Cox proportional hazard model was used to study all-cause mortality and cause-specific mortality between MAFLD and NAFLD, with adjustments for known risk factors. RESULTS: During a median follow-up of 23 years, individuals with MAFLD had a 17% higher risk of all-cause mortality (hazard ratio [HR] 1.17; 95% CI 1.04-1.32). Furthermore, MAFLD was associated with a higher risk of cardiovascular mortality. NAFLD per se did not increase the risk of all-cause mortality. Individuals who met both definitions had a higher risk of all-cause mortality (HR 1.13, 95% CI 1.00-1.26), while individuals who met the definition for MAFLD but not NAFLD had a 1.7-fold higher risk of all-cause mortality (HR 1.66, 95% CI 1.19-2.32). Estimates for all-cause mortality were higher for those with advanced fibrosis and MAFLD than for those with advanced fibrosis and NAFLD. CONCLUSIONS: In this US population-based study, MAFLD was associated with an increased risk of all-cause mortality, while NAFLD demonstrated no association with all-cause mortality after adjusting for metabolic risk factors. LAY SUMMARY: Our findings provide further support for the idea that non-alcoholic fatty liver disease (NAFLD) is a part of a broader multi-system disease that also includes obesity, diabetes, high blood pressure, and high cholesterol. Therefore, re-defining NAFLD as metabolic dysfunction-associated fatty liver disease (MAFLD) may help improve our understanding of predictors that increase the risk of death.
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Hígado Graso/etiología , Enfermedades Metabólicas/complicaciones , Mortalidad/tendencias , Adulto , Índice de Masa Corporal , Hígado Graso/epidemiología , Hígado Graso/mortalidad , Femenino , Humanos , Masculino , Enfermedades Metabólicas/epidemiología , Enfermedades Metabólicas/mortalidad , Factores de Riesgo , Estados Unidos/epidemiologíaRESUMEN
BACKGROUND & AIMS: The association between physical activity (PA) and all-cause and cause-specific mortality from nonalcoholic fatty liver disease (NAFLD) requires investigation. We studied whether PA, measured by accelerometer, is associated with all-cause and cause-specific mortality among individuals with NAFLD. METHODS: We performed a longitudinal analysis using the 2003 to 2006 US National Health and Nutrition Examination Survey data of adults (age, ≥20 y) and collecting mortality data through December 2015. NAFLD was defined based on the hepatic steatosis index or US fatty liver index scores, in the absence of other causes of chronic liver disease. PA was measured from participants who wore accelerometers 10 h/d for a minimum of 4 days over a 7-day period and were classified as total PA, moderate to vigorous PA (MVPA), and sedentary behavior. RESULTS: Over an average follow-up period of 10.6 years, increasing the duration of total PA was associated with a reduced risk of death, from any cause, in an age- and sex-adjusted model (hazard ratio [HR], 0.52; 95% CI, 0.32-0.86 for highest quartile vs lowest quartile; P for trend = .001) and multivariable model (HR, 0.46; 95% CI, 0.28-0.75; P for trend < .001) among individuals with NAFLD. Increasing the duration of MVPA was associated with a lower risk of death from any cause in individuals with NAFLD. Furthermore, longer total PA was associated with a lower risk for cardiovascular disease-related death in individuals with NAFLD (HR, 0.28; 95% CI, 0.08-0.98 for highest quartile vs lowest quartile; P for trend = .007). We did not find this association for cancer-related mortality in individuals with NAFLD. Increasing the duration of sedentary behavior did not affect all-cause or cause-specific mortality in individuals with NAFLD. CONCLUSIONS: Longer total PA and MVPA, measured by accelerometers over a 7-day period, are associated with lower all-cause and cardiovascular mortality in individuals with NAFLD.
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Enfermedades Cardiovasculares , Enfermedad del Hígado Graso no Alcohólico , Adulto , Ejercicio Físico , Humanos , Encuestas Nutricionales , Conducta SedentariaRESUMEN
KEY POINTS: We have developed a novel porcine model of high-thoracic midline contusion spinal cord injury (SCI) at the T2 spinal level. We describe this model and the ensuing cardiovascular and neurohormonal responses, and demonstrate the model is efficacious for studying clinically relevant cardiovascular dysfunction post-SCI. We demonstrate that the high-thoracic SCI model, but not a low-thoracic SCI model, induces persistent hypotension along with a gradual reduction in plasma noradrenaline and increases in plasma aldosterone and angiotensin II. We additionally conducted a proof-of-concept long-term (12 weeks) survival study in animals with T2 contusion SCI demonstrating the potential utility of this model for not only acute experimentation but also long-term drug studies prior to translation to the clinic. ABSTRACT: Cardiovascular disease is a leading cause of morbidity and mortality in the spinal cord injury (SCI) population, especially in those with high-thoracic or cervical SCI. With this in mind, we aimed to develop a large animal (porcine) model of high-thoracic (T2 level) contusion SCI and compare the haemodynamic and neurohormonal responses of this injury against a low-thoracic (T10 level) model. Ten Yorkshire pigs were randomly subjected to 20 cm weight drop contusion SCI at either the T2 or the T10 spinal level. Systolic blood pressure (SBP), mean arterial pressure (MAP) and heart rate (HR) were continuously monitored until 4 h post-SCI. Plasma noradrenaline (NA), aldosterone and angiotensin II (ANGII) were measured pre-SCI and at 30, 60, 120 and 240 min post-SCI. Additionally, two Yucatan pigs were subjected to T2-SCI and survived up to 12 weeks post-injury to demonstrate the efficacy of this model for long-term survival studies. Immediately after T2-SCI, SBP, MAP and HR increased (P < 0.0001). Between decompression (5 min post-SCI) and 30 min post-decompression in T2-SCI, SBP and MAP were lower than pre-SCI (P < 0.038). At 3 and 4 h after T2-SCI, SBP remained lower than pre-SCI (P = 0.048). After T10-SCI, haemodynamic indices remained largely unaffected. Plasma NA was lower in T2- vs. T10-SCI post-SCI, whilst aldosterone and ANGII were higher. Both chronically injured pigs demonstrated a vast reduction in SBP at 12 weeks post-SCI. Our model of T2-SCI causes a rapid and sustained alteration in neurohormonal control and cardiovascular function, which does not occur in the T10 model.
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Sistema Cardiovascular , Traumatismos de la Médula Espinal , Animales , Presión Sanguínea , Modelos Animales de Enfermedad , Hemodinámica , Médula Espinal , PorcinosRESUMEN
Identifying effective therapies for nonalcoholic steatohepatitis (NASH) with fibrosis is a pressing challenge, with 1%-2% of the population in developed nations at risk of developing NASH cirrhosis and its complications. The design of NASH clinical therapeutic trials is hampered by the long period of minimally symptomatic disease that typically precedes the development of decompensated cirrhosis and the accompanying uncertainties regarding the best precirrhotic trial endpoints that reliably reflect a subsequent reduction in liver-related morbidity and mortality. The Liver Forum is a multistakeholder organization comprised of academic, industry, and regulatory experts working from a regulatory science perspective to identify barriers, prioritize research, and identify solutions to accelerate therapeutic development for NASH. Past work of The Liver Forum has focused on recommendations for disease definitions and baseline parameters to be implemented in clinical trials that are designed to assess disease status and prevent progression to cirrhosis, liver transplantation, hepatocellular carcinoma, and death. The purpose of this summary is to review currently available clinical data to identify parameters that change in parallel with liver histology and are likely to reflect clinically meaningful reductions in the risk of developing cirrhosis and its complications. We review available data on exploratory histological, blood-based, and imaging pharmacodynamic biomarkers that may reflect meaningful treatment responses and provide recommendations regarding measurements to be considered in phase 2 and 3 trials as well as during postmarketing monitoring trials.
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Ensayos Clínicos como Asunto/normas , Cirrosis Hepática/terapia , Enfermedad del Hígado Graso no Alcohólico/terapia , Humanos , Cirrosis Hepática/complicaciones , Enfermedad del Hígado Graso no Alcohólico/complicaciones , Índice de Severidad de la Enfermedad , Resultado del TratamientoRESUMEN
Nonalcoholic fatty liver disease (NAFLD) is an increasingly dominant cause of liver disease worldwide. The progressive subtype, nonalcoholic steatohepatitis, is a leading indication for liver transplantation and a noteworthy cause of hepatocellular carcinoma. The overall prevalence of NAFLD is on the rise, and even more concerning data modeling predicts that an increasing percentage of those with NAFLD will develop advanced disease. This increased volume of patients with advanced liver disease will impose a significant health care burden in terms of resources and cost. Thus, the identification of patients with established fibrosis or at high risk of developing advanced liver disease is critical to effectively intervene and prevent overall and liver-related morbidity and mortality. Herein, we provide a framework to consider for the identification of patients with NAFLD at high risk of nonalcoholic steatohepatitis with advanced fibrosis and provide a critical assessment of currently accessible diagnostic and treatment modalities.
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Enfermedad del Hígado Graso no Alcohólico/diagnóstico , Enfermedad del Hígado Graso no Alcohólico/terapia , Biomarcadores/análisis , Biopsia , Diagnóstico por Imagen , Dieta , Progresión de la Enfermedad , Humanos , Hipoglucemiantes/uso terapéutico , Estilo de Vida , Trasplante de Hígado , Pioglitazona/uso terapéutico , Vitamina E/uso terapéuticoRESUMEN
STUDY DESIGN: Review. OBJECTIVES: Clinical studies have shown that the hemodynamic management of patients following acute spinal cord injury (SCI) is an important aspect of their treatment for maintaining spinal cord (SC) perfusion and minimizing ischemic secondary injury to the SC. While this highlights the importance of ensuring adequate perfusion and oxygenation to the injured cord, a method for the real-time monitoring of these hemodynamic measures within the SC is lacking. The purpose of this review is to discuss current and potential methods for SC hemodynamic monitoring with special focus on applications using near-infrared spectroscopy (NIRS). METHODS: A literature search using the PubMed database. All peer-reviewed articles on NIRS monitoring of SC published from inception to May 2019 were reviewed. RESULTS: Among 125 papers related to SC hemodynamics monitoring, 26 focused on direct/indirect NIRS monitoring of the SC. DISCUSSION: Current options for continuous, non-invasive, and real-time monitoring of SC hemodynamics are challenging and limited in scope. As a relatively new technique, NIRS has been successfully used for monitoring human cerebral hemodynamics, and has shown promising results in intraoperative assessment of SC hemodynamics in both human and animal models. Although utilizing NIRS to monitor the SC has been validated, applying NIRS clinically following SCI requires further development and investigation. CONCLUSIONS: NIRS is a promising non-invasive technique with the potential to provide real-time monitoring of relevant parameters in the SC. Currently, in its first developmental stages, further clinical and experimental studies are mandatory to ensure the validity and safety of NIRS techniques.
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Hemodinámica/fisiología , Monitoreo Fisiológico/métodos , Consumo de Oxígeno/fisiología , Espectroscopía Infrarroja Corta/métodos , Traumatismos de la Médula Espinal/metabolismo , Médula Espinal/metabolismo , Animales , Humanos , Monitoreo Fisiológico/tendencias , Espectroscopía Infrarroja Corta/tendencias , Traumatismos de la Médula Espinal/diagnósticoRESUMEN
A 36-year-old man with obesity and dyslipidemia presented with elevated liver enzymes following a liver transplant to treat acute-on-chronic liver failure due to alcohol-associated hepatitis. What would you do next?
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Insuficiencia Hepática Crónica Agudizada , Consumo de Bebidas Alcohólicas , Glicerofosfolípidos , Humanos , Glicerofosfolípidos/sangre , Masculino , Adulto , Insuficiencia Hepática Crónica Agudizada/sangre , Insuficiencia Hepática Crónica Agudizada/etiología , Insuficiencia Hepática Crónica Agudizada/cirugía , Trasplante de Hígado , Hepatitis Alcohólica/complicaciones , Obesidad/complicaciones , Dislipidemias/complicaciones , Consumo de Bebidas Alcohólicas/sangreRESUMEN
During thermogenic activation, brown adipocytes take up large amounts of glucose. In addition, cold stimulation leads to an upregulation of glycolytic enzymes. Here we have investigated the importance of glycolysis for brown adipocyte glucose consumption and thermogenesis. Using siRNA-mediated knockdown in mature adipocytes, we explored the effect of glucose transporters and glycolytic enzymes on brown adipocyte functions such as consumption of glucose and oxygen. Basal oxygen consumption in brown adipocytes was equally dependent on glucose and fatty acid oxidation, whereas isoproterenol (ISO)-stimulated respiration was fueled mainly by fatty acids, with a significant contribution from glucose oxidation. Knockdown of glucose transporters in brown adipocytes not only impaired ISO-stimulated glycolytic flux but also oxygen consumption. Diminishing glycolytic flux by knockdown of the first and final enzyme of glycolysis, i.e., hexokinase 2 (HK2) and pyruvate kinase M (PKM), respectively, decreased glucose uptake and ISO-stimulated oxygen consumption. HK2 knockdown had a more severe effect, which, in contrast to PKM knockdown, could not be rescued by supplementation with pyruvate. Hence, brown adipocytes rely on glucose consumption and glycolytic flux to achieve maximum thermogenic output, with glycolysis likely supporting thermogenesis not only by pyruvate formation but also by supplying intermediates for efferent metabolic pathways.
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Adipocitos Marrones/efectos de los fármacos , Adipocitos Marrones/metabolismo , Agonistas Adrenérgicos beta/farmacología , Glucosa/metabolismo , Glucólisis/efectos de los fármacos , Consumo de Oxígeno/efectos de los fármacos , Tejido Adiposo Pardo/efectos de los fármacos , Tejido Adiposo Pardo/metabolismo , Animales , Células Cultivadas , Regulación hacia Abajo/efectos de los fármacos , Regulación hacia Abajo/fisiología , Ácidos Grasos/metabolismo , Isoproterenol/farmacología , Metabolismo de los Lípidos/efectos de los fármacos , Masculino , Ratones , Oxidación-Reducción/efectos de los fármacos , Termogénesis/efectos de los fármacosRESUMEN
Infections remain a leading cause of morbidity and mortality among patients with liver failure. A number of factors, including relative immune dysfunction and systemic inflammation, bacterial translocation, gut dysbiosis, small intestine bacterial overgrowth, altered bile acid pools, and changes in pH due to acid suppression, contribute to the high rates of infection in this population. Though a range of infections can complicate the course of cirrhotic patients, spontaneous bacterial peritonitis (SBP), cholangitis, and cholecystitis in addition to other infections (i.e. pneumonia, urinary tract infection, bacteremia, and Clostridioides difficile colitis) are more common in this population and will be reviewed in this article. Preventative strategies are directed at minimizing the risk of SBP through the use of targeted antimicrobial prophylaxis. Lastly, the critically ill cirrhotic patient may present with an acute need for liver transplantation. Thus, careful assessment for ongoing infection should be performed and treated to optimize outcomes of transplant, if needed.
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Antibacterianos/uso terapéutico , Infecciones Bacterianas/complicaciones , Fallo Hepático/complicaciones , Trasplante de Hígado , Infecciones Bacterianas/epidemiología , Infecciones Bacterianas/terapia , Enfermedad Crítica , Humanos , Infecciones/clasificación , Fallo Hepático/epidemiología , Fallo Hepático/terapia , Morbilidad/tendencias , Guías de Práctica Clínica como Asunto , Factores de RiesgoRESUMEN
GENERAL PURPOSE: To provide information from a review of literature about economic evaluations of preventive strategies for pressure injuries (PIs). TARGET AUDIENCE: This continuing education activity is intended for physicians, physician assistants, nurse practitioners, and nurses with an interest in skin and wound care. LEARNING OBJECTIVES/OUTCOMES: After participating in this educational activity, the participant should be better able to:1. Identify the purpose and methods used for this study.2. Compare costs and effectiveness related to preventative strategies for PIs. ABSTRACT: BACKGROUND: Pressure injuries (PIs) are a common and resource-intensive challenge for acute care hospitals worldwide. While a number of preventive strategies have the potential to reduce the cost of hospital-acquired PIs, it is unclear what approach is the most effective. OBJECTIVE: The authors performed a narrative review of the literature on economic evaluations of preventive strategies to survey current findings and identify important factors in economic assessments. DATA SOURCES: Ovid, MEDLINE, NHS Economic Evaluation Databases, and the Cochrane Database of Systematic ReviewsSELECTION CRITERIA: Potentially relevant original research articles and systematic reviews were considered. DATA EXTRACTION: Selection criteria included articles that were written in English, provided data on cost or economic evaluations of preventive strategies of PIs in acute care, and published between January 2004 and September 2015. Data were abstracted from the articles using a standardized approach to evaluate how the items on the Consolidated Health Economic Evaluation Reporting Standards checklist were addressed. DATA SYNTHESIS: The searches identified 192 references. Thirty-three original articles were chosen for full-text reviews. Nineteen of these articles provided clear descriptions of interventions, study methods, and outcomes considered. CONCLUSIONS: Limitations in the available literature prevent firm conclusions from being reached about the relative economic merits of the various approaches to the prevention of PIs. The authors' review revealed a need for additional high-quality studies that adhere to commonly used standards of both currently utilized and emerging ways to prevent hospital-acquired PIs.
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Gastos en Salud , Hospitalización/economía , Enfermedad Iatrogénica/economía , Úlcera por Presión/economía , Mejoramiento de la Calidad/economía , Ahorro de Costo , Humanos , Úlcera por Presión/terapiaRESUMEN
The individual contribution of different progenitor subtypes towards the mature rodent cerebral cortex is not fully understood. Intermediate progenitor cells (IPCs) are key to understanding the regulation of neuronal number during cortical development and evolution, yet their exact contribution is much debated. Intermediate progenitors in the cortical subventricular zone are defined by expression of T-box brain-2 (Tbr2). In this study we demonstrate by using the Tbr2(Cre) mouse line and state-of-the-art cell lineage labeling techniques, that IPC derived cells contribute substantial proportions 67.5% of glutamatergic but not GABAergic or astrocytic cells to all cortical layers including the earliest generated subplate zone. We also describe the laminar dispersion of clonally derived cells from IPCs using a recently described clonal analysis tool (CLoNe) and show that pair-generated cells in different layers cluster closer (142.1 ± 76.8 µm) than unrelated cells (294.9 ± 105.4 µm). The clonal dispersion from individual Tbr2 positive intermediate progenitors contributes to increasing the cortical surface. Our study also describes extracortical contributions from Tbr2+ progenitors to the lateral olfactory tract and ventromedial hypothalamic nucleus.
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Corteza Cerebral/embriología , Células-Madre Neurales/fisiología , Células Madre/fisiología , Proteínas de Dominio T Box/metabolismo , Animales , Astrocitos/metabolismo , Astrocitos/fisiología , Encéfalo/embriología , Encéfalo/metabolismo , Corteza Cerebral/metabolismo , Neuronas GABAérgicas/metabolismo , Neuronas GABAérgicas/fisiología , Ventrículos Laterales/metabolismo , Ventrículos Laterales/fisiología , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Células-Madre Neurales/metabolismo , Células Madre/metabolismo , Proteínas de Dominio T Box/genéticaRESUMEN
Although long noncoding RNAs (lncRNAs) are proposed to play essential roles in mammalian neurodevelopment, we know little of their functions from their disruption in vivo. Combining evidence for evolutionary constraint and conserved expression data, we previously identified candidate lncRNAs that might play important and conserved roles in brain function. Here, we demonstrate that the sequence and neuronal transcription of lncRNAs transcribed from the previously uncharacterized Visc locus are conserved across diverse mammals. Consequently, one of these lncRNAs, Visc-2, was selected for targeted deletion in the mouse, and knockout animals were subjected to an extremely detailed anatomical and behavioral characterization. Despite a neurodevelopmental expression pattern of Visc-2 that is highly localized to the cortex and sites of neurogenesis, anomalies in neither cytoarchitecture nor neuroproliferation were identified in knockout mice. In addition, no abnormal motor, sensory, anxiety, or cognitive behavioral phenotypes were observed. These results are important because they contribute to a growing body of evidence that lncRNA loci contribute on average far less to brain and biological functions than protein-coding loci. A high-throughput knockout program focussing on lncRNAs, similar to that currently underway for protein-coding genes, will be required to establish the distribution of their organismal functions.
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Conducta Animal/fisiología , Encéfalo/metabolismo , Secuencia Conservada/genética , ARN Largo no Codificante/genética , Animales , Ansiedad/genética , Secuencia de Bases/genética , Encéfalo/citología , Encéfalo/crecimiento & desarrollo , Evolución Molecular , Femenino , Masculino , Aprendizaje por Laberinto/fisiología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Noqueados , Actividad Motora/genética , Fenotipo , ARN Largo no Codificante/metabolismoRESUMEN
The heritability of abilities increases substantially over development, and much of heritable variation in abilities is shared with other abilities. No study, however, has formally tested the extent to which developmental increases in heritability occur on shared versus unique variation in child abilities. A transactional perspective predicts that the relative proportion of shared to total genetic variance will increase with age, whereas an endogenous perspective predicts that such proportion will be invariant with age. We tested these competing predictions using data from a sample of 292 twins providing a total of 578 cross-sectional and longitudinal observations between ages 0 and 6 years on measures of Communication, Gross Motor, Fine Motor, Problem-Solving, and Personal-Social abilities. Consistent with predictions of the transactional perspective, developmental increases in heritability were localized to variance shared across abilities.
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Desarrollo Infantil , Carácter Cuantitativo Heredable , Aptitud , Niño , Preescolar , Comunicación , Estudios Transversales , Femenino , Humanos , Lactante , Recién Nacido , Estudios Longitudinales , Masculino , Solución de Problemas , Desempeño Psicomotor , Encuestas y CuestionariosRESUMEN
Maximizing science achievement is a critical target of educational policy and has important implications for national and international economic and technological competitiveness. Previous research has identified both science interest and socioeconomic status (SES) as robust predictors of science achievement, but little research has examined their joint effects. In a data set drawn from approximately 400,000 high school students from 57 countries, we documented large Science Interest × SES and Science Interest × Per Capita Gross Domestic Product (GDP) interactions in the prediction of science achievement. Student interest in science is a substantially stronger predictor of science achievement in higher socioeconomic contexts and in higher-GDP nations. Our results are consistent with the hypothesis that in higher-opportunity contexts, motivational factors play larger roles in learning and achievement. They add to the growing body of evidence indicating that substantial cross-national differences in psychological effect sizes are not simply a logical possibility but, in many cases, an empirical reality.