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81.
Background
Autonomic nervous system (ANS) dysfunction is present in up to one third of patients with tetanus. The prognostic value of ANS dysfunction is known in severe tetanus but its value is not well established in mild to moderate tetanus. 相似文献82.
Cancer patients are at increased risk for thrombosis. Among the predisposing factors for the hemostatic imbalance, drugs have a definite role. Induction of thrombosis by drugs involves a variety of mechanisms: Enhancement of procoagulant activity, reduction in anticoagulants synthesis, stimulation of platelet aggregation and endothelial damage. L-asparaginase is associated with thrombotic events, mainly in the venous system. Supportive therapy with fresh frozen plasma is probably insufficient and heparin needs further evaluation. Venous thromboembolism has recently emerged following thalidomide use particularly in combination chemotherapy. The hematopoietic growth factors granulocyte colony-stimulating factor, macrophage-granulocyte colony-stimulating factor and erythropoietin have also been implicated in venous as well as in arterial thrombotic events. Numerous drugs are associated with thrombotic microangiopathy i.e., cyclosporine A, tacrolimus, cisplatin, bleomycin, gemcitabine. The clinical presentation, pathological mechanisms and therapeutic modalities are discussed. 相似文献
83.
Effects of losartan on the blood-brain barrier permeability in long-term nitric oxide blockade-induced hypertensive rats 总被引:1,自引:0,他引:1
Kucuk M Kaya M Kalayci R Cimen V Kudat H Arican N Elmas I Korkut F 《Life sciences》2002,71(8):937-946
Hypertension is closely associated with vascular endothelial dysfunction. The aim of this study was to investigate the effects of Angiotensin II (ANG II) receptor antagonist losartan on the blood-brain barrier (BBB) permeability in L-NAME-induced hypertension and/or in ANG II-induced acute hypertension in normotensive and hypertensive rats. Systolic blood pressure was measured by tail cuff method before, during and following L-NAME treatment (1 g/L). Losartan (3 mg/kg) was given to the animal for five days. Acute hypertension was induced by ANG II (60 microg/kg). Arterial blood pressure was directly measured on the day of the experiment. BBB disruption was quantified according to the extravasation of the albumin-bound Evans blue dye. Losartan significantly reduced the mean arterial blood pressure from 169 +/- 3.9 mmHg to 82 +/- 2.9 mmHg in L-NAME and from 171 +/- 2.9 mmHg to 84 +/- 2.9 in L-NAME plus losartan plus ANG II groups (p < 0.05). The content of Evans blue dye in the cerebral cortex significantly increased in L-NAME (p < 0.01). Moreover, the content of Evans blue dye markedly increased in the cerebellum (p < 0.001) and slightly increased in diencephalon region (p < 0.05) in L-NAME plus ANG II. Losartan reduced the increased BBB permeability to Evans blue dye in L-NAME (p < 0.01) and L-NAME plus ANG II (p < 0.001). These results indicate that L-NAME and L-NAME plus ANG II both lead to an increase in microvascular Evans blue dye efflux to brain, and losartan treatment attenuates this protein-bound dye transport into brain tissue presumably due to its protective effect on endothelial cells of brain vessels. 相似文献
84.
Evren Terzi Cokun Kse Ümit Büyüksar Erkan Avc Nadir Ayrlm S. Nami Kartal 《International biodeterioration & biodegradation》2009,63(6):806-809
Particleboard specimens produced by adding waste tire rubber particles were assayed against white- and brown-rot fungi and termites in laboratory conditions. Particleboards were manufactured from a mixture of pine and poplar particles bonded with two different resins (melamine/urea formaldehyde [MUF] and polyisocyanate [PI]) by adding waste tire rubber particles at three different levels (10%/90%, 20%/80%, and 30%/70% by weight of waste tire rubber/wood). The particleboard specimens with waste tire rubber were not generally resistant against four fungi tested. Only MUF-containing specimens showed considerably better performance in decay resistance tests using the brown-rot fungus, Postia placenta; however, addition of waste tire rubber into those specimens did not provide resistance in comparison with control specimens without tire rubber. Formosan termites were also able to degrade particleboard specimens with waste tire rubber. 相似文献
85.
Helen Bothwell Sarah Bisbing Nina Overgaard Therkildsen Lindsay Crawford Nadir Alvarez Rolf Holderegger Stéphanie Manel 《Conservation Genetics》2013,14(2):467-481
It is generally accepted that most plant populations are locally adapted. Yet, understanding how environmental forces give rise to adaptive genetic variation is a challenge in conservation genetics and crucial to the preservation of species under rapidly changing climatic conditions. Environmental variation, phylogeographic history, and population demographic processes all contribute to spatially structured genetic variation, however few current models attempt to separate these confounding effects. To illustrate the benefits of using a spatially-explicit model for identifying potentially adaptive loci, we compared outlier locus detection methods with a recently-developed landscape genetic approach. We analyzed 157 loci from samples of the alpine herb Gentiana nivalis collected across the European Alps. Principle coordinates of neighbor matrices (PCNM), eigenvectors that quantify multi-scale spatial variation present in a data set, were incorporated into a landscape genetic approach relating AFLP frequencies with 23 environmental variables. Four major findings emerged. 1) Fifteen loci were significantly correlated with at least one predictor variable (R adj 2 > 0.5). 2) Models including PCNM variables identified eight more potentially adaptive loci than models run without spatial variables. 3) When compared to outlier detection methods, the landscape genetic approach detected four of the same loci plus 11 additional loci. 4) Temperature, precipitation, and solar radiation were the three major environmental factors driving potentially adaptive genetic variation in G. nivalis. Techniques presented in this paper offer an efficient method for identifying potentially adaptive genetic variation and associated environmental forces of selection, providing an important step forward for the conservation of non-model species under global change. 相似文献
86.
Onal Merih Kocak Nadir Duymus Fahrettin Bozkurt Mete Kaan Elsurer Cagdas Erdur Omer Onal Ozkan 《Molecular biology reports》2021,48(7):5579-5586
Molecular Biology Reports - Tonsil tissue is a very important component of the human immunity system, contributing to the functioning of the cellular and humoral defence system, especially in... 相似文献
87.
Muhammad Kamran Fabrizio Frontalini Dang-Peng Xi Kamran Mirza Arman Jafarian Khalid Latif Fahad Ali Muhammad Kashif Nadir Fawad Muhammad Shafi Xiao-Qiao Wan 《Palaeoworld》2021,30(2):337-355
The Middle Eocene Climatic Optimum (MECO) at ~40 Ma is a significant global warming event associated with pronounced changes in the hydrosphere, atmosphere, and biosphere. The Kohat Formation in the Kohat Basin (eastern Tethys, Pakistan) is studied for identifying the response of larger benthic foraminifera (LBF) to MECO. The LBF assemblages in the Kohat Formation, covering from the Shallow Benthic Zones (SBZ) 15 to 17, suggest middle Lutetian to early Bartonian in age. Microfacies analyses indicate a lagoonal (inner carbonate ramp facies belt) to open marine (middle carbonate ramp facies belt) paleodepositional environment of the Kohat Formation. A distinct positive δ13C shift marks the stratigraphic position of the MECO in this formation. At the Peak-MECO event that is marked by the onset of the positive carbon isotope excursion (CIE), no evident compositional variation in the LBF assemblages is observed. However, significant changes in the LBF assemblages with the local first and last occurrences of some LBF genera can be observed in the Post-MECO and CIE recovery phase. These changes are verified by the sudden disappearance of Alveolina and orthophragminids and initial dominance of larger shell-size Nummulites fabianii, Heterostegina, and Linderina species accompanied by an increase in the species diversity. Here, we argue that the change in the observed LBF assemblages in the uppermost part of the Kohat Formation might be related to a larger foraminiferal turnover occurring during the Post-MECO event and corresponds to the CIE recovery phase. 相似文献
88.
For the last 2 decades, supertree reconstruction has been an active field of research and has seen the development of a large number of major algorithms. Because of the growing popularity of the supertree methods, it has become necessary to evaluate the performance of these algorithms to determine which are the best options (especially with regard to the supermatrix approach that is widely used). In this study, seven of the most commonly used supertree methods are investigated by using a large empirical data set (in terms of number of taxa and molecular markers) from the worldwide flowering plant family Sapindaceae. Supertree methods were evaluated using several criteria: similarity of the supertrees with the input trees, similarity between the supertrees and the total evidence tree, level of resolution of the supertree and computational time required by the algorithm. Additional analyses were also conducted on a reduced data set to test if the performance levels were affected by the heuristic searches rather than the algorithms themselves. Based on our results, two main groups of supertree methods were identified: on one hand, the matrix representation with parsimony (MRP), MinFlip, and MinCut methods performed well according to our criteria, whereas the average consensus, split fit, and most similar supertree methods showed a poorer performance or at least did not behave the same way as the total evidence tree. Results for the super distance matrix, that is, the most recent approach tested here, were promising with at least one derived method performing as well as MRP, MinFlip, and MinCut. The output of each method was only slightly improved when applied to the reduced data set, suggesting a correct behavior of the heuristic searches and a relatively low sensitivity of the algorithms to data set sizes and missing data. Results also showed that the MRP analyses could reach a high level of quality even when using a simple heuristic search strategy, with the exception of MRP with Purvis coding scheme and reversible parsimony. The future of supertrees lies in the implementation of a standardized heuristic search for all methods and the increase in computing power to handle large data sets. The latter would prove to be particularly useful for promising approaches such as the maximum quartet fit method that yet requires substantial computing power. 相似文献
89.
Bjørn Økland Nadir Erbilgin Olav Skarpaas Erik Christiansen Bo Långström 《Biological invasions》2011,13(5):1151-1164
Frequent bark beetle outbreaks cause biome-scale impacts in boreal and temperate forests worldwide. Despite frequent interceptions at ports of entry, the most aggressive bark beetle species of Ips and Dendroctonus in North America and Eurasia have failed to establish outside their original home continents. Our experiments showed that Ips typographus can breed in six North American spruce species: Engelmann spruce, white spruce¸ Sitka spruce, Lutz spruce, black spruce and red spruce. This suggests that differences between the Eurasian historical host and North American spruce species are not an insurmountable barrier to establishment of this tree-killing species in North America. However, slightly diminished quality of offspring beetles emerged from the North American spruces could reduce the chance of establishment through an Allee effect. The probabilistic nature of invasion dynamics suggests that successful establishments can occur when the import practice allows frequent arrivals of non-indigenous bark beetles (increased propagule load). Model simulations of hypothetical interactions of Dendroctonus rufipennis and I. typographus indicated that inter-species facilitations could result in more frequent and severe outbreaks than those caused by I. typographus alone. The potential effects of such new dynamics on coniferous ecosystems may be dramatic and extensive, including major shifts in forest structure and species composition, increased carbon emissions and stream flow, direct and indirect impacts on wildlife and invertebrate communities, and loss of biodiversity. 相似文献
90.
Hande Bas Ayata Metin Güden Cemile Ceylan Nadir Kücük Kayihan Engin 《Reports of Practical Oncology and Radiotherapy》2011,16(3):95-102