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61.
Several studies have shown that chronic alcoholics have increased susceptibility to infections due to higher exposure to infectious agents as well as breakdown in their immune defenses. As Strongyloides stercoralis infection is usually more relevant in immunocompromised patients, the aim of this study was to evaluate the frequency of S. stercoralis infection in alcoholics. Thus, coproparasitological examination was carried out in 145 subjects, from which 45 were chronic alcoholics (mean age of 45.7 +/- 11.0 years), 10 were nonalcoholic cirrhotic patients (mean age of 50.2 +/- 13.1 years), and 90 were asymptomatic nonalcoholic subjects (mean age of 46.7 +/- 10.1 years), which served as controls. From the alcoholics, 9 had hepatic cirrhosis, 9 had chronic pancreatitis and 27 had neither cirrhosis nor pancreatitis. For the diagnosis of strongyloidiasis, the Baermann-Moraes and Lutz methods were used in three fecal samples from each subject. Samples were collected at alternated days, and three slides of each sample were analyzed for each method, thus totalizing 2,610 slides examined. The frequency of strongloidiasis in the total alcoholic group (33.3%) and in the subgroups of alcoholics, i.e., patients with hepatic cirrhosis (44.4%), with chronic pancreatitis (33.3%), and those with no cirrhosis or pancreatitis (29.6%) was statistically higher than that found in the control group (5.5%). None of the individuals with nonalcoholic hepatic cirrhosis had S. stercoralis infection. Our results showed that the chronic alcoholism itself is an important factor that predisposes to strongyloidiasis.  相似文献   
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63.
Recent global commitments have placed forest and landscape restoration at the forefront of countries' efforts to recover ecosystem services, conserve biodiversity, and mitigate the effects of climate change. However, it needs to be asked if current native tree seedling supply meets an increase in demand for forest restoration? This study assessed the current configuration, distribution, and production capacity of forest nurseries producing native trees in Brazil. Brazil provides an interesting example of how global agreements aligned with national policies can lead to the proliferation of native seedling nurseries, and the challenges faced to restore species‐rich native forest ecosystems. We found that the nurseries in the Atlantic Forest region can still meet an increase in demand—both in terms of seedling quantity and diversity—because most of their production capacity is not currently used. However, not all Brazilian biomes have sufficient nurseries to meet restoration demands, thus there is a risk of using native species from a few biogeographical regions in a much spatially wider and ecologically diverse area. In addition, lack of seed supply and qualified labor can hamper the growth of the market. Barriers to seed supply may also lead to low levels of genetic variability and floristic representation in the populations and ecosystems to be restored. We conclude that restoration of high‐diversity forest ecosystems requires policies and supportive programs, with emphasis on private nurseries, to guarantee adequate supply of native tree seedlings and provide the necessary incentives to develop the emergent economy of forest restoration.  相似文献   
64.
65.
The viability of algae-based biodiesel industry depends on the selection of adequate strains in regard to profitable yields and oil quality. This work aimed to bioprospecting and screening 12 microalgae strains by applying, as selective criteria, the volumetric lipid productivity and the fatty acid profiles, used for estimating the biodiesel fuel properties. Volumetric lipid productivity varied among strains from 22.61 to 204.91 mg l?1 day?1. The highest lipid yields were observed for Chlorella (204.91 mg l?1 day1) and Botryococcus strains (112.43 and 98.00 mg l?1 day?1 for Botryococcus braunii and Botryococcus terribilis, respectively). Cluster and principal components analysis analysis applied to fatty acid methyl esters (FAME) profiles discriminated three different microalgae groups according to their potential for biodiesel production. Kirchneriella lunaris, Ankistrodesmus fusiformis, Chlamydocapsa bacillus, and Ankistrodesmus falcatus showed the highest levels of polyunsaturated FAME, which incurs in the production of biodiesels with the lowest (42.47–50.52) cetane number (CN), the highest (101.33–136.97) iodine values (IV), and the lowest oxidation stability. The higher levels of saturated FAME in the oils of Chlamydomonas sp. and Scenedesmus obliquus indicated them as source of biodiesel with higher oxidation stability, higher CN (63.63–64.94), and lower IV (27.34–35.28). The third group, except for the Trebouxyophyceae strains that appeared in isolation, are composed by microalgae that generate biodiesel of intermediate values for CN, IV, and oxidation stability, related to their levels of saturated and monosaturated lipids. Thus, in this research, FAME profiling suggested that the best approach for generating a microalgae-biodiesel of top quality is by mixing the oils of distinct cell cultures.  相似文献   
66.
Right ventricular (RV) afterload is commonly defined as pulmonary vascular resistance, but this does not reflect the afterload to pulsatile flow. The purpose of this study was to quantify RV afterload more completely in patients with and without pulmonary hypertension (PH) using a three-element windkessel model. The model consists of peripheral resistance (R), pulmonary arterial compliance (C), and characteristic impedance (Z). Using pulmonary artery pressure from right-heart catheterization and pulmonary artery flow from MRI velocity quantification, we estimated the windkessel parameters in patients with chronic thromboembolic PH (CTEPH; n = 10) and idiopathic pulmonary arterial hypertension (IPAH; n = 9). Patients suspected of PH but in whom PH was not found served as controls (NONPH; n = 10). R and Z were significantly lower and C significantly higher in the NONPH group than in both the CTEPH and IPAH groups (P < 0.001). R and Z were significantly lower in the CTEPH group than in the IPAH group (P < 0.05). The parameters R and C of all patients obeyed the relationship C = 0.75/R (R(2) = 0.77), equivalent to a similar RC time in all patients. Mean pulmonary artery pressure P and C fitted well to C = 69.7/P (i.e., similar pressure dependence in all patients). Our results show that differences in RV afterload among groups with different forms of PH can be quantified with a windkessel model. Furthermore, the data suggest that the RC time and the elastic properties of the large pulmonary arteries remain unchanged in PH.  相似文献   
67.
A series of succinyl hydroxamates/bishydroxamates as well as a new structural type of matrix metalloproteinase (MMP)/bacterial protease (BP) inhibitors, incorporating iminodiacetic (IDA) hydroxamate/bishydroxamate moieties, has been synthesized and tested for interaction with four vertebrate proteases, MMP-1, MMP-2, MMP-8 and MMP-9, and a BP, the collagenase isolated from Clostridium histolyticum (ChC). The new derivatives generally showed inhibition constants in the range of 8-62 nM against the five proteases mentioned above.  相似文献   
68.
Floristic differentiation and vegetation definition is an important step to recognize biome distribution and for biodiversity conservation. Here, we aim to verify if the distribution of the costal lowland vegetation in Brazilian littoral is congruent with climatic gradient and the previous vegetation definitions. Additionally we discussed the importance of terms for the Atlantic Forest conservation. Our study was based on floristic and geo-climatic data from 58 published surveys. We generate a checklist of 1088 woody species and verified species distribution according to environmental gradient using a Detrended Correspondence Analysis (DCA). We compared DCA??s groups with the a priori vegetation definition and generate an a posteriori classification using TWINSPAN. DCA and TWINSPAN resulted in groups determined mainly by rainfall (r = ?0.65) and soil sandiness (r = ?0.71). Those groups were not congruent with both the previous vegetation definitions. The coastal lowland vegetation comprises two distinctive floristic groups representing forests and scrubs that occur in wetter climates (Ombrophilous lowland forests) in the Brazilian states of Santa Catarina, Paraná and São Paulo and in drier climates of Espírito Santo, Rio de Janeiro (Restinga-Northern group) and Rio Grande do Sul (Restinga-Southern group) states. The floristic and historical relationships between Ombrophylous lowland forests and Restingas suggest that conservation initiatives should be more conservative and treat collectively all coastal lowland vegetation as a biodiversity hotspot.  相似文献   
69.
Gap junctions are specialized cell-cell contacts that provide direct intercellular communication between eukaryotic cells. The tyrosine-sorting signal (YXX?), present at amino acids 286-289 of Cx43 (connexin43), has been implicated in the internalization of the protein. In recent years, ubiquitination of Cx43 has also been proposed to regulate gap junction intercellular communication; however, the underlying mechanism and molecular players involved remain elusive. In the present study, we demonstrate that ubiquitinated Cx43 is internalized through a mechanism that is independent of the YXX? signal. Indeed, expression of a Cx43-Ub (ubiquitin) chimaera was shown to drive the internalization of a mutant Cx43 in which the YXX? motif was eliminated. Immunofluorescence, cycloheximide-chase and cell-surface-protein biotinylation experiments demonstrate that oligomerization of Cx43-Ub into hemichannels containing wild-type Cx43 or mutant Cx43Y286A is sufficient to drive the internalization of the protein. Furthermore, the internalization of Cx43 induced by Cx43-Ub was shown to depend on its interaction with epidermal growth factor receptor substrate 15.  相似文献   
70.
Three anthracene derivatives, auxenone, oncocalyxonol and auxemim, were isolated from Auxemma ontocalyx. The structures of these compounds as 1,4,8-trihydroxy-2-methoxy-5-methyl-9,10-anthraquinone, rel-9alpha,11alpha-epoxy-1,4,8alpha,11alpha-tetrahydroxy-2-methoxy-8a beta-methyl-5,6,7,8,8a,9, 10,10a beta-octahydro-10-anthracenone and rel-8alpha,11beta-epoxy-2,11-dimethoxy-8a beta-methyl-5,6,7,8,8a,9-hexahydro-1,4-anthracenedione were determined by analysis of spectral data (1D and 2D NMR, IR, HREIMS and UV).  相似文献   
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