Impacts of Arctic Shrubs on Root Traits and Belowground Nutrient Cycles Across a Northern Alaskan Climate Gradient.

Deciduous shrubs are expanding across the graminoid-dominated nutrient-poor arctic tundra. Absorptive root traits of shrubs are key determinants of nutrient acquisition strategy from tundra soils, but the variations of shrub root traits within and among common shrub genera across the arctic climatic gradient are not well resolved. Consequently, the impacts of arctic shrub expansion on belowground nutrient cycling remain largely unclear. Here, we collected roots from 170 plots of three commonly distributed shrub genera (Alnus, Betula, and Salix) and a widespread sedge (Eriophorum vaginatum) along a climatic gradient in northern Alaska. Absorptive root traits that are relevant to the strategy of plant nutrient acquisition were determined. The influence of aboveground dominant vegetation cover on the standing root biomass, root productivity, vertical rooting profile, as well as the soil nitrogen (N) pool in the active soil layer was examined. We found consistent root trait variation among arctic plant genera along the sampling transect. Alnus and Betula had relatively thicker and less branched, but more frequently ectomycorrhizal colonized absorptive roots than Salix, suggesting complementarity between root efficiency and ectomycorrhizal dependence among the co-existing shrubs. Shrub-dominated plots tended to have more productive absorptive roots than sedge-dominated plots. At the northern sites, deep absorptive roots (>20 cm depth) were more frequent in birch-dominated plots. We also found shrub roots extensively proliferated into the adjacent sedge-dominated plots. The soil N pool in the active layer generally decreased from south to north but did not vary among plots dominated by different shrub or sedge genera. Our results reveal diverse nutrient acquisition strategies and belowground impacts among different arctic shrubs, suggesting that further identifying the specific shrub genera in the tundra landscape will ultimately provide better predictions of belowground dynamics across the changing arctic.

Downregulation of histone methyltransferase EHMT2 in CD4+ T-cells may protect HTLV-1-infected individuals against HAM/TSP development.

Approximately 5% of human T-cell leukemia virus type 1 (HTLV-1)-infected individuals will develop one of the HTLV-1-related diseases, such as HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) or adult T-cell leukemia. However, the mechanisms responsible for the appearance of symptoms have not been fully clarified. It is believed that viral factors, host genetic and epigenetic mechanisms are implicated in this process. Studies have shown the involvement of histone methyltransferases in retrovirus infection, but no study observed their expression in HTLV-1-infected patients. Among them, euchromatic histone-lysine N-methyltransferase (EHMT)-1 and EHMT-2 were related to retroviral latency in HIV-1 infection. We investigated whether histone methyltransferases EHMT1 and EHMT2 exert any influence on HAM/TSP development by assessing their expression levels in CD4+ T-cells from HTLV-1-infected patients. CD4+ T-cells were immunomagnetically isolated from peripheral blood mononuclear cells of HTLV-1-infected or non-infected individuals and the expression levels of EHMT1 and EHMT2 were determined by RT-qPCR. We observed that EHMT2 was negatively regulated in HTLV-1 asymptomatic carriers compared to non-infected individuals. No difference was observed for EHMT1. These results suggest that EHMT2 downregulation in CD4+ T-cells may be linked to a protection mechanism against the development of HAM/TSP.

Use of noninvasive ventilation in severe acute respiratory distress syndrome due to accidental chlorine inhalation: a case report. / Uso da ventilação não invasiva em síndrome do desconforto respiratório agudo grave por inalação acidental de cloro: um relato de caso.

Acute respiratory distress syndrome is characterized by diffuse inflammatory lung injury and is classified as mild, moderate, and severe. Clinically, hypoxemia, bilateral opacities in lung images, and decreased pulmonary compliance are observed. Sepsis is one of the most prevalent causes of this condition (30 - 50%). Among the direct causes of acute respiratory distress syndrome, chlorine inhalation is an uncommon cause, generating mucosal and airway irritation in most cases. We present a case of severe acute respiratory distress syndrome after accidental inhalation of chlorine in a swimming pool, with noninvasive ventilation used as a treatment with good response in this case. We classified severe acute respiratory distress syndrome based on an oxygen partial pressure/oxygen inspired fraction ratio <100, although the Berlin classification is limited in considering patients with severe hypoxemia managed exclusively with noninvasive ventilation. The failure rate of noninvasive ventilation in cases of acute respiratory distress syndrome is approximately 52% and is associated with higher mortality. The possible complications of using noninvasive positive-pressure mechanical ventilation in cases of acute respiratory distress syndrome include delays in orotracheal intubation, which is performed in cases of poor clinical condition and with high support pressure levels, and deep inspiratory efforts, generating high tidal volumes and excessive transpulmonary pressures, which contribute to ventilation-related lung injury. Despite these complications, some studies have shown a decrease in the rates of orotracheal intubation in patients with acute respiratory distress syndrome with low severity scores, hemodynamic stability, and the absence of other organ dysfunctions.

Uso da ventilação não invasiva em síndrome do desconforto respiratório agudo grave por inalação acidental de cloro: um relato de caso / Use of noninvasive ventilation in severe acute respiratory distress syndrome due to accidental chlorine inhalation: a case report

RESUMO A síndrome do desconforto respiratório agudo é caracterizada por lesão pulmonar inflamatória difusa, classificada em leve, moderada e grave. Clinicamente observam-se hipoxemia, opacidades bilaterais na imagem pulmonar e diminuição da complacência pulmonar. A sepse está entre as causas mais prevalentes (30 - 50%). Dentre as causas diretas de síndrome do desconforto respiratório agudo, a inalação de cloro é uma causa incomum, gerando, na maior parte dos casos, irritação de mucosas e vias aéreas. Apresentamos um caso de síndrome do desconforto respiratório agudo grave após inalação acidental de cloro em piscina, sendo utilizada ventilação não invasiva como tratamento com boa resposta neste caso. Classificamos como síndrome do desconforto respiratório agudo grave baseado na relação pressão parcial de oxigênio/fração inspirada de oxigênio < 100, embora a classificação de Berlin seja limitada em considerar pacientes com hipoxemia grave manejados exclusivamente com ventilação não invasiva. A taxa de falha da ventilação não invasiva nos casos de síndrome do desconforto respiratório agudo está em torno de 52%, estando associada à maior mortalidade. As possíveis complicações do uso da ventilação mecânica não invasiva com pressão positiva na síndrome do desconforto respiratório agudo seriam o atraso para a intubação orotraqueal sendo a mesma realizada em uma condição clínica pior e um alto nível de pressões de suporte, somados a esforços inspiratórios profundos, gerando elevados volumes correntes e pressões transpulmonares excessivas, que contribuem para injúria pulmonar associada à ventilação. Apesar disto, alguns estudos mostraram diminuição nas taxas de intubação orotraqueal em pacientes com síndrome do desconforto respiratório Agudo com baixos escores de gravidade, estabilidade hemodinâmica e ausência de outras disfunções orgânicas.

ABSTRACT Acute respiratory distress syndrome is characterized by diffuse inflammatory lung injury and is classified as mild, moderate, and severe. Clinically, hypoxemia, bilateral opacities in lung images, and decreased pulmonary compliance are observed. Sepsis is one of the most prevalent causes of this condition (30 - 50%). Among the direct causes of acute respiratory distress syndrome, chlorine inhalation is an uncommon cause, generating mucosal and airway irritation in most cases. We present a case of severe acute respiratory distress syndrome after accidental inhalation of chlorine in a swimming pool, with noninvasive ventilation used as a treatment with good response in this case. We classified severe acute respiratory distress syndrome based on an oxygen partial pressure/oxygen inspired fraction ratio <100, although the Berlin classification is limited in considering patients with severe hypoxemia managed exclusively with noninvasive ventilation. The failure rate of noninvasive ventilation in cases of acute respiratory distress syndrome is approximately 52% and is associated with higher mortality. The possible complications of using noninvasive positive-pressure mechanical ventilation in cases of acute respiratory distress syndrome include delays in orotracheal intubation, which is performed in cases of poor clinical condition and with high support pressure levels, and deep inspiratory efforts, generating high tidal volumes and excessive transpulmonary pressures, which contribute to ventilation-related lung injury. Despite these complications, some studies have shown a decrease in the rates of orotracheal intubation in patients with acute respiratory distress syndrome with low severity scores, hemodynamic stability, and the absence of other organ dysfunctions.

Anomalia de UHL / UHL's anomaly

A anomalia de Uhl é uma doença considerada congênita do ventrículo direito, caracterizada pela ausência total do miocárdio ventricular, de etiologia ignorada, com frequência clínica bastante incomum, que se expressa, preferencialmente, no paciente neonato. Tratando-se de enfermidade raramente reportada na literatura médica, a anomalia de Uhl é muito pouco conhecida no universo da pediatria e até pela grande maioria dos cardiologistas. Este trabalho procura abordar as bases morfofuncionais, clínicas e do tratamento da doença em questäo, em regime de revisäo e de atualizaçäo do assunto.

Cardiopatia neoplásica / Neoplasic cardiopathy

Mesmo diante do avanço propedêutico observado na Cardiologia moderna, devido à sua freqüência clínica realmente incomum, a chamada Cardiopatia Neoplásica exibe reduzido reconhecimento diagnóstico na prática médica. Os tumores cardíacos primários benignos sao menos raros do que os malignos, com predominância, neste aspecto, dos mixomas, ao passo que, em termos de câncer metastático, as neoplasias broncogênicas e de mama sao as que mais envolvem o coraçao durante seu curso evolutivo.