Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 43
Filtrar
1.
Science ; 368(6498): 1477-1481, 2020 06 26.
Artigo em Inglês | MEDLINE | ID: mdl-32587019

RESUMO

The closet exoplanets to the Sun provide opportunities for detailed characterization of planets outside the Solar System. We report the discovery, using radial velocity measurements, of a compact multiplanet system of super-Earth exoplanets orbiting the nearby red dwarf star GJ 887. The two planets have orbital periods of 9.3 and 21.8 days. Assuming an Earth-like albedo, the equilibrium temperature of the 21.8-day planet is ~350 kelvin. The planets are interior to, but close to the inner edge of, the liquid-water habitable zone. We also detect an unconfirmed signal with a period of ~50 days, which could correspond to a third super-Earth in a more temperate orbit. Our observations show that GJ 887 has photometric variability below 500 parts per million, which is unusually quiet for a red dwarf.

2.
Case Rep Med ; 2020: 5730704, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32047518

RESUMO

Sarcoidosis is a systemic granulomatous disease of unknown aetiology characterised by the appearance of noncaseifying epithelioid granulomas in the affected organs, most commonly the lungs, skin, and eyes (Iannuzzi et al. 2007). Necrotizing Sarcoid Granulomatosis (NGS) is a rare and little-known form of disease, which also presents nodular lung lesions, and it shares pathologic and clinical findings with sarcoidosis, where the presence of necrosis may lead to misdiagnosis of tuberculosis (TB), leading to a consequent delay in treatment of the underlying entity (Chong et al. 2015). This is exactly what happened with the two cases that we present here.

3.
Artigo em Inglês | MEDLINE | ID: mdl-31707090

RESUMO

Adolescence is a developmental period marked by robust neural alterations and heightened vulnerability to stress, a factor that is highly associated with increased risk for emotional processing deficits, such as anxiety. Stress-induced upregulation of the dynorphin/kappa opioid receptor (DYN/KOP) system is thought to, in part, underlie the negative affect associated with stress. The basolateral amygdala (BLA) is a key structure involved in anxiety, and neuromodulatory systems, such as the DYN/KOP system, can 1) regulate BLA neural activity in an age-dependent manner in stress-naïve animals and 2) underlie stress-induced anxiety in adults. However, the role of the DYN/KOP system in modulating stress-induced anxiety in adolescents is unknown. To test this, we examined the impact of an acute, 2-day forced swim stress (FSS - 10 min each day) on adolescent (~postnatal day (P) 35) and adult Sprague-Dawley rats (~P70), followed by behavioral, molecular and electrophysiological assessment 24 h following FSS. Adolescent males, but not adult males or females of either age, demonstrated social anxiety-like behavioral alterations indexed via significantly reduced social investigation and preference when tested 24 h following FSS. Conversely, adult males exhibited increased social preference. While there were no FSS-induced changes in expression of genes related to the DYN/KOP system in the BLA, these behavioral alterations were associated with alterations in BLA KOP function. Specifically, while GABA transmission in BLA pyramidal neurons from non-stressed adolescent males responded variably (potentiated, suppressed, or was unchanged) to the KOP agonist, U69593, U69593 significantly inhibited BLA GABA transmission in the majority of neurons from stressed adolescent males, consistent with the observed anxiogenic phenotype in stressed adolescent males. This is the first study to demonstrate stress-induced alterations in BLA KOP function that may contribute to stress-induced social anxiety in adolescent males. Importantly, these findings provide evidence for potential KOP-dependent mechanisms that may contribute to pathophysiological interactions with subsequent stress challenges.


Assuntos
Ansiedade/psicologia , Complexo Nuclear Basolateral da Amígdala/metabolismo , Receptores Opioides kappa/metabolismo , Estresse Psicológico/psicologia , Natação/psicologia , Envelhecimento/psicologia , Animais , Ansiedade/etiologia , Ansiedade/genética , Dinorfinas/metabolismo , Feminino , Masculino , Técnicas de Patch-Clamp , Células Piramidais/metabolismo , Ratos , Ratos Sprague-Dawley , Receptores Opioides kappa/genética , Caracteres Sexuais , Comportamento Social , Estresse Psicológico/complicações , Estresse Psicológico/genética , Transmissão Sináptica , Ácido gama-Aminobutírico/fisiologia
5.
Neuropharmacology ; 117: 124-133, 2017 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-28163104

RESUMO

Anxiety disorders are one of the most common and debilitating mental illnesses worldwide. Growing evidence indicates an age-dependent rise in the incidence of anxiety disorders from adolescence through adulthood, suggestive of underlying neurodevelopmental mechanisms. Kappa opioid receptors (KORs) are known to contribute to the development and expression of anxiety; however, the functional role of KORs in the basolateral amygdala (BLA), a brain structure critical in mediating anxiety, particularly across ontogeny, are unknown. Using whole-cell patch-clamp electrophysiology in acute brain slices from adolescent (postnatal day (P) 30-45) and adult (P60+) male Sprague-Dawley rats, we found that the KOR agonist, U69593, increased the frequency of GABAA-mediated spontaneous inhibitory postsynaptic currents (sIPSCs) in the adolescent BLA, without an effect in the adult BLA or on sIPSC amplitude at either age. The KOR effect was blocked by the KOR antagonist, nor-BNI, which alone did not alter GABA transmission at either age, and the effect of the KOR agonist was TTX-sensitive. Additionally, KOR activation did not alter glutamatergic transmission in the BLA at either age. In contrast, U69593 inhibited sIPSC frequency in the central amygdala (CeA) at both ages, without altering sIPSC amplitude. Western blot analysis of KOR expression indicated that KOR levels were not different between the two ages in either the BLA or CeA. This is the first study to provide compelling evidence for a novel and unique neuromodulatory switch in one of the primary brain regions involved in initiating and mediating anxiety that may contribute to the ontogenic rise in anxiety disorders.


Assuntos
Envelhecimento/fisiologia , Complexo Nuclear Basolateral da Amígdala/metabolismo , Receptores Opioides kappa/fisiologia , Ácido gama-Aminobutírico/fisiologia , Animais , Complexo Nuclear Basolateral da Amígdala/efeitos dos fármacos , Benzenoacetamidas/antagonistas & inibidores , Benzenoacetamidas/farmacologia , Ácido Glutâmico/fisiologia , Potenciais Pós-Sinápticos Inibidores/efeitos dos fármacos , Masculino , Naltrexona/análogos & derivados , Naltrexona/farmacologia , Pirrolidinas/antagonistas & inibidores , Pirrolidinas/farmacologia , Ratos , Receptores Opioides kappa/agonistas , Receptores Opioides kappa/antagonistas & inibidores , Receptores Opioides kappa/biossíntese , Transmissão Sináptica/efeitos dos fármacos
6.
Eur J Paediatr Neurol ; 20(3): 426-30, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26943985

RESUMO

UNLABELLED: Harlequin syndrome (HS) is a rare autonomic disorder due to a hemifacial cutaneous sympathetic denervation. It is characterized by unilateral diminished sweating and flushing of the face even though after heat or prolonged exercise. It is typically acquired. Congenital cases only represent a 6% of all individuals with HS. All congenital HS cases reported so far showed a concomitant Horner syndrome, probably due to a stellate ganglion involvement. HS represents an uncommon autonomic disorder due to a hemifacial cutaneous sympathetic denervation. It is clinically characterized by a dramatic alteration in facial appearance: ipsilateral denervated pale and dry half from the other intact red and moist half. CONCLUSION: We present, to the best of our knowledge, the first case of a patient with a congenital HS as an isolated phenomenon.


Assuntos
Doenças do Sistema Nervoso Autônomo/congênito , Doenças do Sistema Nervoso Autônomo/diagnóstico , Rubor/congênito , Rubor/diagnóstico , Hipo-Hidrose/congênito , Hipo-Hidrose/diagnóstico , Doenças Raras/congênito , Doenças Raras/diagnóstico , Face , Humanos , Lactente , Masculino
7.
Geobiology ; 12(3): 231-49, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24612324

RESUMO

Despite the importance of oolitic depositional systems as indicators of climate and reservoirs of inorganic C, little is known about the microbial functional diversity, structure, composition, and potential metabolic processes leading to precipitation of carbonates. To fill this gap, we assess the metabolic gene carriage and extracellular polymeric substance (EPS) development in microbial communities associated with oolitic carbonate sediments from the Bahamas Archipelago. Oolitic sediments ranging from high-energy 'active' to lower energy 'non-active' and 'microbially stabilized' environments were examined as they represent contrasting depositional settings, mostly influenced by tidal flows and wave-generated currents. Functional gene analysis, which employed a microarray-based gene technology, detected a total of 12,432 of 95,847 distinct gene probes, including a large number of metabolic processes previously linked to mineral precipitation. Among these, gene-encoding enzymes for denitrification, sulfate reduction, ammonification, and oxygenic/anoxygenic photosynthesis were abundant. In addition, a broad diversity of genes was related to organic carbon degradation, and N2 fixation implying these communities has metabolic plasticity that enables survival under oligotrophic conditions. Differences in functional genes were detected among the environments, with higher diversity associated with non-active and microbially stabilized environments in comparison with the active environment. EPS showed a gradient increase from active to microbially stabilized communities, and when combined with functional gene analysis, which revealed genes encoding EPS-degrading enzymes (chitinases, glucoamylase, amylases), supports a putative role of EPS-mediated microbial calcium carbonate precipitation. We propose that carbonate precipitation in marine oolitic biofilms is spatially and temporally controlled by a complex consortium of microbes with diverse physiologies, including photosynthesizers, heterotrophs, denitrifiers, sulfate reducers, and ammonifiers.


Assuntos
Archaea/genética , Bactérias/genética , Carbonatos/metabolismo , Fungos/genética , Variação Genética , Sedimentos Geológicos/microbiologia , Archaea/metabolismo , Bactérias/metabolismo , Bahamas , Ciclo do Carbono , Fungos/metabolismo , Ciclo do Nitrogênio , Reação em Cadeia da Polimerase , Enxofre/metabolismo
8.
Lupus ; 20(12): 1321-3, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21719526
9.
J Appl Microbiol ; 110(6): 1571-83, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21447014

RESUMO

AIMS: Research into the relationship between pathogens, faecal indicator microbes and environmental factors in beach sand has been limited, yet vital to the understanding of the microbial relationship between sand and the water column and to the improvement of criteria for better human health protection at beaches. The objectives of this study were to evaluate the presence and distribution of pathogens in various zones of beach sand (subtidal, intertidal and supratidal) and to assess their relationship with environmental parameters and indicator microbes at a non-point source subtropical marine beach. METHODS AND RESULTS: In this exploratory study in subtropical Miami (Florida, USA), beach sand samples were collected and analysed over the course of 6 days for several pathogens, microbial source tracking markers and indicator microbes. An inverse correlation between moisture content and most indicator microbes was found. Significant associations were identified between some indicator microbes and pathogens (such as nematode larvae and yeasts in the genus Candida), which are from classes of microbes that are rarely evaluated in the context of recreational beach use. CONCLUSIONS: Results indicate that indicator microbes may predict the presence of some of the pathogens, in particular helminthes, yeasts and the bacterial pathogen Staphylococcus aureus including methicillin-resistant forms. Indicator microbes may thus be useful for monitoring beach sand and water quality at non-point source beaches. SIGNIFICANCE AND IMPACT OF THE STUDY: The presence of both indicator microbes and pathogens in beach sand provides one possible explanation for human health effects reported at non-point sources beaches.


Assuntos
Bactérias/isolamento & purificação , Praias , Monitoramento Ambiental/métodos , Helmintos/isolamento & purificação , Microbiologia da Água , Leveduras/isolamento & purificação , Animais , Contagem de Colônia Microbiana , Florida , Água do Mar/microbiologia , Água do Mar/parasitologia , Dióxido de Silício/análise
10.
Pediatr. aten. prim ; 13(49): 127-134, ene.-mar. 2011. ilus
Artigo em Espanhol | IBECS | ID: ibc-86369

RESUMO

Pese a la elevada incidencia de displasia de cadera clínicamente importante (3-5 casos por cada 1000 recién nacidos vivos) y a los ampliamente estudiados factores de riesgo principales (parto de presentación podálica, sexo femenino y antecedentes familiares de displasia evolutiva de cadera), no se ha conseguido encontrar una estrategia efectiva que reduzca la incidencia de casos tardíos. Reabrimos, a propósito de un caso, la controversia existente acerca del cribado ecográfico universal en la patología osteomuscular más frecuente de la infancia (AU)


Despite the elevated incidence of clinically relevant hip dysplasia (3-5 per 1000 live births) and the broadly studied main risk factors (breech position, female sex and family cases), we have not achieved an effective prevention strategy, and so the detection of late cases has not decreased. We reopen, following a case, the existent controversy upon universal ultrasound screening on the most frequent musculo-skeletal disorder in the infancy (AU)


Assuntos
Humanos , Masculino , Feminino , Recém-Nascido , Luxação Congênita de Quadril , Programas de Rastreamento/métodos , Fatores de Risco , Ultrassonografia , Acetábulo/lesões , Acetábulo/fisiopatologia , Osteoartrite/complicações , Osteoartrite/diagnóstico
11.
Alcohol ; 43(1): 25-33, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19185207

RESUMO

Withdrawal (WD) anxiety is a significant factor contributing to continued alcohol abuse in alcoholics. This anxiety is extensive, long-lasting, and develops well after the obvious physical symptoms of acute WD. The neurobiological mechanisms underlying this prolonged WD-induced anxiety are not well understood. The basolateral amygdala (BLA) is a major emotional center in the brain and regulates the expression of anxiety. New evidence suggests that increased glutamatergic function in the BLA may contribute to WD-related anxiety following chronic ethanol exposure. Recent evidence also suggests that kainate-type ionotropic glutamate receptors are inhibited by intoxicating concentrations of acute ethanol. This acute sensitivity suggests potential (KA-R) contributions by these receptors to the increased glutamatergic function seen during chronic exposure. Therefore, we examined the effect of chronic intermittent ethanol (CIE) and WD on KA-R-mediated synaptic transmission in the BLA of Sprague-Dawley rats. Our study showed that CIE, but not WD, increased synaptic responses mediated by KA-Rs. Interestingly, both CIE and WD occluded KA-R-mediated synaptic plasticity. Finally, we found that BLA field excitatory postsynaptic potential responses were increased during CIE and WD via a mechanism that is independent of glutamate release from presynaptic terminals. Taken together, these data suggest that KA-Rs might contribute to postsynaptic increases in glutamatergic synaptic transmission during CIE and that the mechanisms responsible for the expression of KA-R-dependent synaptic plasticity might be engaged by chronic ethanol exposure and WD.


Assuntos
Tonsila do Cerebelo/efeitos dos fármacos , Depressores do Sistema Nervoso Central/farmacologia , Etanol/farmacologia , Receptores de Ácido Caínico/efeitos dos fármacos , Síndrome de Abstinência a Substâncias/fisiopatologia , Transmissão Sináptica/efeitos dos fármacos , Alanina/análogos & derivados , Alanina/farmacologia , Animais , Encéfalo/patologia , Estimulação Elétrica , Eletrofisiologia , Potenciais Pós-Sinápticos Excitadores/efeitos dos fármacos , Masculino , Plasticidade Neuronal/efeitos dos fármacos , Técnicas de Patch-Clamp , Ratos , Ratos Sprague-Dawley , Receptores de Glutamato/efeitos dos fármacos
12.
J Org Chem ; 73(15): 6048-51, 2008 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-18598082

RESUMO

The transformation of enantiopure (2R,4R)- and (2S,4S)-N,N-dibenzyl-1,2:4,5-diepoxypentan-3-amine, 1 and 2, into the corresponding enantiopure (3S,5S)- and (3R,5R)-3,5-dihydroxy-3-aminopiperidines, 3 and 4 respectively, is described. The opening of the two epoxide rings with a range of amines takes place with total regioselectivity and high yields, in the presence of LiClO4. A mechanism to explain this transformation is proposed.


Assuntos
Aminas/química , Compostos de Epóxi/química , Piperidinas/química , Serina/química , Estrutura Molecular , Estereoisomerismo
14.
J Clin Microbiol ; 45(6): 1874-83, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17442792

RESUMO

A Luminex suspension array, which had been developed for identification of Cryptococcus neoformans and Cryptococcus gattii isolates, was tested by genotyping a set of 58 mostly clinical isolates. All genotypes of C. neoformans and C. gattii were included. In addition, cerebrospinal fluid (CSF) obtained from patients with cryptococcal meningitis was used to investigate the feasibility of the technique for identification of the infecting strain. The suspension array correctly identified haploid isolates in all cases. Furthermore, hybrid isolates possessing two alleles of the Luminex probe region could be identified as hybrids. In CSF specimens, the genotype of the cryptococcal strains responsible for infection could be identified after optimization of the PCR conditions. However, further optimization of the DNA extraction protocol is needed to enhance the usability of the method in clinical practice.


Assuntos
Cryptococcus neoformans/classificação , Cryptococcus/classificação , Citometria de Fluxo/métodos , Técnicas de Tipagem Micológica , Reação em Cadeia da Polimerase/métodos , Adulto , Idoso , Líquido Cefalorraquidiano/microbiologia , Criptococose/microbiologia , Cryptococcus/genética , Cryptococcus/isolamento & purificação , Cryptococcus neoformans/genética , Cryptococcus neoformans/isolamento & purificação , DNA Fúngico/análise , DNA Fúngico/isolamento & purificação , Feminino , Genótipo , Humanos , Masculino , Meningite Criptocócica/microbiologia , Microesferas , Pessoa de Meia-Idade , Dados de Sequência Molecular , Análise de Sequência de DNA , Especificidade da Espécie , Suspensões
15.
Philos Trans R Soc Lond B Biol Sci ; 360(1462): 1897-903, 2005 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-16214747

RESUMO

After the process of DNA barcoding has become well advanced in a group of organisms, as it has in the economically important fungi, the question then arises as to whether shorter and literally more barcode-like DNA segments should be utilized to facilitate rapid identification and, where applicable, detection. Through appropriate software analysis of typical full-length barcodes (generally over 500 base pairs long), uniquely distinctive oligonucleotide 'microcodes' of less than 25 bp can be found that allow rapid identification of circa 100-200 species on various array-like platforms. Microarrays can in principle fulfill the function of microcode-based species identification but, because of their high cost and low level of reusability, they tend to be less cost-effective. Two alternative platforms in current use in fungal identification are reusable nylon-based macroarrays and the Luminex system of specific, colour-coded DNA detection beads analysed by means of a flow cytometer. When the most efficient means of rapid barcode-based species identification is sought, a choice can be made either for one of these methodologies or for basic high-throughput sequencing, depending on the strategic outlook of the investigator and on current costs. Arrays and functionally similar platforms may have a particular advantage when a biologically complex material such as soil or a human respiratory secretion sample is analysed to give a census of relevant species present.


Assuntos
Biodiversidade , DNA/genética , Processamento Eletrônico de Dados/métodos , Fungos/genética , Técnicas de Diagnóstico Molecular/métodos , Citometria de Fluxo , Análise em Microsséries/métodos , Oligonucleotídeos/genética , Especificidade da Espécie
18.
Rev Neurol ; 38(3): 249-52, 2004.
Artigo em Espanhol | MEDLINE | ID: mdl-14963854

RESUMO

INTRODUCTION: Prenatal intracranial anomalies of a cystic nature are mainly either malformations (arachnoid cysts) or disruptive (porencephaly). They are usually incidental findings and, unless they undergo a progressive increase in size and become expansile or offer clinical features, they are usually managed 'expectantly'. Disruptive defects are more frequent in twin pregnancies. CASE REPORT: A one and a half-month-old male patient, fruit of a bichorial twin pregnancy, with bouts of paleness, cyanosis around the mouth and movements of the mouth that initially responded to treatment with valproate. Physical exploration was normal except for a significant increase in the cephalic perimeter. A notable anaemia was observed and neuroimaging revealed a left temporal intraparenchymatous cystic lesion; in addition, magnetic resonance imaging showed alterations in the linear and symmetrical signals in the parasagittal region. At three months the seizures reappeared and the cyst had increased in size, which led to the implantation of a cyst peritoneal shunt. The seizures ceased and the size of the cyst became stable, without full re expansion of the brain tissue. DISCUSSION: It is necessary to carry out a differential diagnosis of an arachnoid cyst and porencephaly. Given the history of being a twin, the notable degree of anaemia at the age of one month and the image suggesting parasagittal cerebral injury (a pattern of hypoxic ischemic encephalopathy in the full term neonate), we think that our patient was suffering from antenatal or perinatal cerebrovascular damage, which conditioned the development of an expansile porencephalic cyst and cortical damage that accounted for the symptoms of epilepsy.


Assuntos
Cistos Aracnóideos/etiologia , Encéfalo/anormalidades , Doenças em Gêmeos , Epilepsias Parciais/etiologia , Hipóxia-Isquemia Encefálica/congênito , Anemia/etiologia , Anticonvulsivantes/uso terapêutico , Apneia/etiologia , Cistos Aracnóideos/diagnóstico , Cistos Aracnóideos/cirurgia , Cianose/etiologia , Diagnóstico Diferencial , Progressão da Doença , Epilepsias Parciais/tratamento farmacológico , Humanos , Hipóxia-Isquemia Encefálica/complicações , Lactente , Imageamento por Ressonância Magnética , Masculino , Procedimentos Neurocirúrgicos , Cavidade Peritoneal , Lobo Temporal/patologia , Gêmeos Dizigóticos , Ácido Valproico/uso terapêutico
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...