Isoprene, monoterpene, and other volatile organic compound (VOC) emissions from grasslands, shrublands, forests, and peatlands in China were characterized to estimate their regional magnitudes and to ...compare these emissions with those from landscapes of North America, Europe, and Africa. Ecological and VOC emission sampling was conducted at 52 sites centered in and around major research stations located in seven different regions of China: Inner Mongolia (temperate), Changbai Mountain (boreal‐temperate), Beijing Mountain (temperate), Dinghu Mountain (subtropical), Ailao Mountain (subtropical), Kunming (subtropical), and Xishuangbanna (tropical). Transects were used to sample plant species and growth form composition, leafy (green) biomass, and leaf area in forests representing nearly all the major forest types of China. Leafy biomass was determined using generic algorithms based on tree diameter, canopy structure, and absolute cover. Measurements of VOC emissions were made on 386 of the 541 recorded species using a portable photo‐ionization detector method. For 105 species, VOC emissions were also measured using a flow‐through leaf cuvette sampling/gas chromatography analysis method. Results indicate that isoprene and monoterpene emissions, as well as leafy biomass, vary systematically along gradients of ecological succession in the same manner found in previous studies in the United States, Canada, and Africa. Applying these results to a regional VOC emissions model, we arrive at a value of 21 Tg C for total annual biogenic VOC emissions from China, compared to 5 Tg C of VOCs released annually from anthropogenic sources there. The isoprene and monoterpene emissions are nearly the same as those reported for Europe, which is comparable in size to China.
Vegetation composition and biomass were surveyed for three specific sites in Atlanta, GA; near Rhinelander, WI; and near Hayden, CO. At each research site emissions of biogenic volatile organic ...compounds (BVOCs) from the dominant vegetation species were sampled by enclosing branches in bag enclosure systems and sampling the equilibrium head space onto multi-stage solid adsorbent cartridges. Analysis was performed using a thermal desorption technique with gas chromatography (GC) separation and mass spectrometry (MS) detection. Identification of BVOCs covering the GC retention index range (stationary phase DB-1) from approximately 400 to 1400 was achieved (volatilities C
4 – C
14).
Identificar e sumarizar evidências científicas sobre a eficácia do uso do ácido tranexâmico na prevenção de hemorragia em puérperas.
O estudo apresentou como cerne o sistema Paciente/Problema, ...Intervenção, Comparação e Resultado (PICO), o qual viabilizou recursos para busca de dados nas principais bases científicas (MEDLINE PubMed). Os termos utilizados na pesquisa foram: tranexamic acid; postpartum haemorrhage; delivery; puerperium . Foram utilizados como critérios de inclusão: Diretrizes e artigos completos, realizados em humanos, publicados em língua inglesa. Foram excluídos artigos que não associaram Transamin a eventos hemorrágicos após o parto e estudos anteriores ao ano de publicação da última diretriz sobre o tema (2017).
A utilização de ácido tranexâmico (TXA) mostrou-se efetiva em diminuir a mortalidade relacionada à hemorragia pós-parto. O experimento WOMAN, comparou mulheres medicadas com Transamin e placebo, demonstrou que o uso do tratamento diminuiu a mortalidade por hemorragia nos partos vaginais e cesáreos, principalmente se administrado nas 3 primeiras horas pós parto, este, porém, perde 10% do benefício, a cada 15 minutos de atraso na infusão. Consequentemente, ocorreram 33% menos laparotomias para controle de hemorragia após partos. Alguns estudos colocam o TXA, como profilaxia para partos cesáreos, e os resultados mostraram 60% de diminuição de hemorragias leves e moderadas, 68% para hemorragias severas e 70% da necessidade de transfusão sanguínea. Uma grande preocupação ao usar o TXA, é a possibilidade da ocorrência de eventos tromboembólicos, porém, os estudos mostraram que o seu uso, não aumentou a incidência.
A literatura evidencia que a hemorragia é a principal causa de mortalidade materna, sendo que no período pós-parto grande parte das mortes ocorrem nas primeiras 24 horas após o nascimento. Tal condição reflete um desequilíbrio entre os sistemas de coagulação e fibrinólise, no parto e puerpério imediato, devido a altos níveis do ativador do plasminogênio tecidual, os quais estimulam a via fibrinolítica. Nesse sentido, o uso de TXA, um inibidor da fibrinólise, mostrou-se ser uma estratégia válida e aplicável. Com base nisso, tem-se que a utilização de TXA recomendada se concentra em uma dose fixa 1 g (100 mg/ml) por via intravenosa a 1ml/ min, com uma segunda dose de 1g por via intravenosa se o sangramento continuar após 30 minutos ou reiniciar dentro de 24 horas após o término da primeira dose. Como efeitos adversos, o TXA esteve associado a quadros de náusea e vômito e não promoveu o desenvolvimento de eventos vasculares oclusivos dentro de 3 meses após o parto.
Tendo em vista as publicações, há efetividade do ácido tranexâmico em reduzir a mortalidade materna associada a hemorragia pós-parto. O melhor prognóstico é iniciar precocemente a administração logo após o princípio do sangramento. Recomenda-se o uso do Transamin 1 grama intravenosa em até 3 horas pós-parto, houve redução de laparotomias e transfusões sanguíneas e revelou-se que não há aumento de ocorrências de eventos tromboembólicos. De acordo com a exposição, conclui-se que o uso do ácido tranexâmico para prevenção e no tratamento de hemorragias em puérperas pode ser realizado de forma segura e eficiente.
Autosomal dominant polycystic kidney disease (ADPKD), Type I is a common genetic disorder and an important cause of renal failure. The disease is characterized by progressive cyst formation in a ...variety of organs including the kidney, liver and pancreas. We have previously shown that in the case of
PKD1, renal cyst development is likely to require somatic inactivation of the normal allele coupled to a germline
PKD1 mutation. In this report, we have used unique reagents to show that intragenic, somatic mutations are common in hepatic cysts. All pathogenic mutations were shown to have altered the previously normal copy of the gene. These data extend the “two-hit” model of cystogenesis to include a second focal manifestation of the disease.
Biogenic volatile organic compounds (BVOCs) were measured on tethered balloon platforms in 11 deployments between 1985 and 1996. A series of balloon sampling packages have been used to describe ...boundary layer dynamics, BVOC distribution, chemical transformations of BVOCs, and to estimate BVOC emission rates from terrestrial vegetation. Measurements indicated a slow decrease of concentration for BVOCs with altitude in the mixed layer when sampling times were greater than average convective turnover time; surface layer concentrations were more variable because of proximity to various emission sources in the smaller surface layer footprint. Mixed layer concentrations of isoprene remained fairly constant in the middle of the day, in contrast to canopy-level isoprene concentrations, which continued to increase until early evening. Daytime emissions, which increase with temperature and light, appear to be balanced by changes in entrainment and oxidation. Daytime measurements of methacrolein and methyl vinyl ketone, reaction products of the atmospheric oxidation of isoprene, showed fairly constant ratio to each other with altitude throughout the mixed layer. BVOC emission flux estimates using balloon measurements and from the extrapolation of leaf level emissions to the landscape scale were in good agreement.
Landscape flux potentials for biogenic volatile organic compounds (BVOCs) were derived for three ecosystems in the continental U.S. (Fernbank Forest, Atlanta, GA; Willow Creek, Rhinelander, WI; ...Temple Ridge, CO). Analytical data from branch enclosure measurements were combined with ecological survey data for plant species composition and biomass.Other quantitative flux measurements at the leaf and landscape level were incorporated to scale the results from the enclosure measurements to the landscape level.Flux estimates were derived by using a one week ambient temperature and light record (30 min time resolution) and adjusting all emission rates to these conditions with temperature and light correction algorithms.
The molecular signature that defines tumor microvasculature will likely provide clues as to how vascular-dependent tumor proliferation is regulated. Using purified endothelial cells, we generated a ...database of gene expression changes accompanying vascular proliferation in invasive breast cancer. In contrast to normal mammary vasculature, invasive breast cancer vasculature expresses extracellular matrix and surface proteins characteristic of proliferating and migrating endothelial cells. We define and validate the up-regulated expression of VE-cadherin and osteonectin in breast tumor vasculature. In contrast to other tumor types, invasive breast cancer vasculature induced a high expression level of specific transcription factors, including SNAIL1 and HEYL, that may drive gene expression changes necessary for breast tumor neovascularization. We demonstrate the expression of HEYL in tumor endothelial cells and additionally establish the ability of HEYL to both induce proliferation and attenuate programmed cell death of primary endothelial cells in vitro. We also establish that an additional intracellular protein and previously defined metastasis-associated gene, PRL3, appears to be expressed predominately in the vasculature of invasive breast cancers and is able to enhance the migration of endothelial cells in vitro. Together, our results provide unique insights into vascular regulation in breast tumors and suggest specific roles for genes in driving tumor angiogenesis.
In temperate regions the chemistry of the lower troposphere is known to be significantly affected by biogenic volatile organic compounds (VOCs) emitted by plants. The chemistry of the lower ...troposphere over the tropics, however, is poorly understood, in part because of the considerable uncertainties in VOC emissions from tropical ecosystems. Present global VOC models predict that base emissions of isoprene from tropical rainforests are considerably higher than from savannas. These global models of VOC emissions which rely mainly on species inventories are useful, but significant improvement might be made with more ecologically based models of VOC emissions by plants. Ecosystems along a successional transect from woodland savanna to primary rainforest in central Africa were characterized for species composition and vegetation abundance using ground surveys and remotely sensed data. A total of 336 species (mostly trees) at 13 sites were recorded, and 208 of these were measured for VOC emissions at near‐optimal light and temperature conditions using a leaf cuvette and hand‐held photoionization detector (PID). A subset of 59 species was also sampled using conventional VOC emission techniques in order to validate the PID technique. Results of ecological and VOC emission surveys indicate both phylogenetic and successional patterns along the savanna‐rainforest transect. Genera and families of trees which tend to emit isoprene include Lophira, Irvingia, Albizia, Artocarpus, Ficus, Pterocarpus, Caesalpiniaceae, Arecaceae, and Moraceae. Other taxa tend to contain stored VOCs (Annonaceae and Asteraceae). Successional patterns suggest that isoprene emissions are highest in the relatively early successional Isoberlinia forest communities and progressively decrease in the later successional secondary and primary rainforest communities. Stored VOCs appear to increase along the savanna‐rainforest succession, but these data are more tentative. These findings are consistent with successional patterns of isoprene and terpene fluxes in North American forests and highlight the feasibility of constructing better predictive models of VOC emissions.
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