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排序方式: 共有1019条查询结果,搜索用时 15 毫秒
1.
Paul McDonough D Merrill Dane Connie C W Hsia Cuneyt Yilmaz Robert L Johnson 《Journal of applied physiology》2006,100(2):474-481
In a previous study, our laboratory showed that young dogs born at sea level (SL) and raised from 2.5 mo of age to beyond somatic maturity at a high altitude (HA) of 3,100 m show enhanced resting lung function (Johnson RL Jr, Cassidy SS, Grover RF, Schutte JE, and Epstein RH. J Appl Physiol 59: 1773-1782, 1985). To examine whether HA-induced adaptation improves pulmonary gas exchange during exercise and whether adaptation is reversible when animals return to SL before somatic maturity, we raised 2.5-mo-old foxhounds at HA (3,800 m) for 5 mo (to age 7.5 mo) before returning them to SL. Lung function was measured under anesthesia 1 mo and 2 yr after return to SL and during exercise approximately 1 yr after return. In animals exposed to HA relative to simultaneous litter-matched SL controls, resting circulating blood and erythrocyte volumes, lung volumes, septal volume estimated by a rebreathing technique, and lung tissue volume estimated by high-resolution computed tomography scan were persistently higher. Lung diffusing capacity, membrane diffusing capacity, and pulmonary capillary blood volume estimated at a given cardiac output were significantly higher in animals exposed to HA, whereas maximal oxygen uptake and hematocrit were similar between groups. We conclude that relatively short exposure to HA during somatic maturation improves long-term lung function into adulthood. 相似文献
2.
Effect of Digestion with Phospholipase A2 on Endogenous Protein Phosphorylation in Particulate Fractions from Rat Brain Synaptosomes 总被引:1,自引:1,他引:0
The endogenous phosphorylation of synapsin 1 in cyclic AMP-containing media was greatly decreased by digestion of synaptic vesicles and synaptosomal membranes with phospholipase A2, suggesting that the system is functionally dependent on the membrane structure. Treatment of the synaptic vesicle fraction with phospholipase A2 also caused a small but significant inhibition of the Ca2+/calmodulin-dependent phosphorylation of the same protein. The Ca2+/calmodulin-dependent phosphorylation of other major acceptors, and the basal phosphorylation of a 52-kD acceptor enriched in the vesicle fraction, remained unchanged after cleavage of the membrane phospholipids with phospholipase A2. The significance of the selective effect of phospholipase A2 treatment on endogenous membrane phosphorylation is discussed. 相似文献
3.
Masanori Ito Kazuhiro Yoshida Eikai Kyo Ayse Ayhan Hirofumi Nakayama Wataru Yasui Hisao Ito Eiichi Tahara 《Virchows Archiv. B, Cell pathology including molecular pathology》1990,59(1):173-178
We have examined the expression of mRNAs for epidermal growth factor (EGF), transforming growth factor-alpha (TGF-α), EGF
receptor (EGFR), PDGF-A chain (PDGFA), PDGF-B chain (PDGFB) and PDGF receptor (PDGFR) genes in seven human colorectal carcinoma
cell lines and 18 human colorectal carcinomas.
In surgically resected specimens of the 18 colorectal tumors, TGF-α, EGFR, PDGFA, PDGFB and PDGFR mRNAs were detected at various
levels in 15 (83%), 9 (50%), 18 (100%), 8 (44%) and 12 (67%), respectively. They were also detected in normal tissues. Interestingly,
EGF mRNA was detected in only five (28%) of the tumors, but not in normal mucosa. Expression of EGF was also confirmed immunohistochemically
in tumor cells. Of the five tumors expressing EGF, four expressed EGFR mRNA and showed a tendency to invade veins and lymphatics.
All the colorectal carcinoma cell lines expressed TGF-α mRNA, and five cell lines expressed EGFR mRNA simultaneously. Production
of TGF-α protein by DLD-1 and CoLo320DM cells was confirmed by TGF-α specific monoclonal antibody binding assay. The spontaneous3H-thymidine uptake by DLD-1 was suppressed by an anti-TGF-α monoclonal antibody. PDGFA and PDGFB mRNA were also expressed
in four cell lines, but PDGFR and EGF mRNA was not detected. These results suggest that human colorectal carcinomas express
multi-loops of growth factors and that TGF-α produced by tumor cells functions as an autocrine growth factor in human colonic
carcinoma. 相似文献
4.
W J Malaisse M T Yilmaz F Malaisse-Lagae A Sener 《Biochemical medicine and metabolic biology》1988,40(1):35-41
In rat pancreatic islets, tumoral islet cells (RINm5F line), parotid gland, and in human erythrocytes, but not in rat hepatocytes, the production of 3H2O from D-[2-3H]glucose is 20-30% lower than from D-[5-3H]glucose. This coincides with the production of tritiated lactic acid from D-[2-3H]glucose and may be attributable to an intramolecular hydrogen transfer in the phosphoglucoisomerase reaction. It is concluded that the production of 3H2O from D-[2-3H]glucose is not a reliable tool to assess the total rate of hexose phosphorylation. 相似文献
5.
Endogenous protein phosphorylation patterns were compared in occluded and non-occluded cytosol fractions prepared from rat forebrain. The occluded fraction was taken as representative of synaptosomal cytosol. One- and two-dimensional autoradiographs revealed the presence in non-occluded cytosol of a substrate for cAMP- and Ca2+/calmodulin-dependent protein kinase activities of Mr 300kD, corresponding to phosphorylated microtubule-associated protein-2 (MAP-2); this protein was absent in occluded cytosol. In contrast, a major substrate for protein kinase C was observed exclusively in occluded cytosol after phosphorylation under basal conditions. However, after phosphorylation in the presence of exogenous lipids, approximately equal amounts of the 82kD substrate were detected in both fractions, suggesting that protein kinase C in the occluded fraction was present in a partially activated state. Other minor differences in phosphorylation patterns between the two fractions were observed.Special Issue dedicated to Prof. Eduardo De Robertis. 相似文献
6.
Lasse T. Keetz Eva Lieungh Kaveh Karimi-Asli Sonya R. Geange Emiliano Gelati Hui Tang Yeliz A. Yilmaz Kjetil S. Aas Inge H. J. Althuizen Anders Bryn Stefanie Falk Rosie Fisher Anne Fouilloux Peter Horvath Sunniva Indrehus Hanna Lee Danica Lombardozzi Frans-Jan W. Parmentier Norbert Pirk Vigdis Vandvik Ane V. Vollsnes Olav Skarpaas Frode Stordal Lena M. Tallaksen 《Global Change Biology》2023,29(15):4440-4452
Dynamic Global Vegetation Models (DGVMs) provide a state-of-the-art process-based approach to study the complex interplay between vegetation and its physical environment. For example, they help to predict how terrestrial plants interact with climate, soils, disturbance and competition for resources. We argue that there is untapped potential for the use of DGVMs in ecological and ecophysiological research. One fundamental barrier to realize this potential is that many researchers with relevant expertize (ecology, plant physiology, soil science, etc.) lack access to the technical resources or awareness of the research potential of DGVMs. Here we present the Land Sites Platform (LSP): new software that facilitates single-site simulations with the Functionally Assembled Terrestrial Ecosystem Simulator, an advanced DGVM coupled with the Community Land Model. The LSP includes a Graphical User Interface and an Application Programming Interface, which improve the user experience and lower the technical thresholds for installing these model architectures and setting up model experiments. The software is distributed via version-controlled containers; researchers and students can run simulations directly on their personal computers or servers, with relatively low hardware requirements, and on different operating systems. Version 1.0 of the LSP supports site-level simulations. We provide input data for 20 established geo-ecological observation sites in Norway and workflows to add generic sites from public global datasets. The LSP makes standard model experiments with default data easily achievable (e.g., for educational or introductory purposes) while retaining flexibility for more advanced scientific uses. We further provide tools to visualize the model input and output, including simple examples to relate predictions to local observations. The LSP improves access to land surface and DGVM modelling as a building block of community cyberinfrastructure that may inspire new avenues for mechanistic ecosystem research across disciplines. 相似文献
7.
In the context of the proposed work, two different amino acids (Glycine, Phenylalanine) have interacted with copper ions in a phosphate buffer (PBS) in place of enzymes. This interaction resulted in the nucleation of copper phosphate crystals and the formation of flower-shaped amino acid-copper hybrid nanostructures (AA-hNFs), which grew through self-assembly. While Cu (II) ions in the structure of AA-hNFs were used as Fenton's agent for the catalytic activity. SEM, energy dispersive X-ray spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy measurements were used to define the AA-hNFs′ characterisation. The peroxidase-like activities of AA-hNFs were investigated by UV/VIS spectrophotometer. Metal nanoparticles have peroxidase-like activity. A class of enzymes known as peroxidases is able to catalyze the conversion of hydrogen peroxide into hydroxyl radicals. These radicals also take part in electron transfers with substrates, which results in color during oxidation. When cupric oxide nanoparticles are added to the peroxidase substrate while H2O2 is present, a blue color product with a maximum absorbance at=652 nm can result, demonstrating the catalytic activity of a peroxidase. The morphology and composition of AA-hNFs were carefully characterized and the synthesized parameters were optimized systematically. Results showed that the nanoparticles were dispersed with an average diameter of 7–9 μm and indicated a uniform flower shape. The results of the investigation are anticipated to significantly advance a number of technical and scientific sectors. 相似文献
8.
Maria Tsekoura Evdokia Billis Elias Tsepis Sofia Lampropoulou Charlotte Beaudart Olivier Bruyere Ozlem Yilmaz Gullistan Bahat John Gliatis 《Journal of musculoskeletal & neuronal interactions》2020,20(4):505
Objective:To translate and validate into Greek, the SARC-F questionnaire, a screening tool for sarcopenia.Methods:Questionnaire was back-translated and culturally adapted into Greek according to guidelines proposed by the World Health Organization. A convenience sample of 197 Greek elderly people (71.6±7.8 years, 68.5% women) was recruited, 64 of which were classified as persons at risk of sarcopenia according to the SARC-F. Internal consistency, test-retest and inter-rater reliability were evaluated. Validity (sensitivity, specificity, predictive positive value and predictive negative value) was assessed against the definition from the European Working Group of Sarcopenia in Older People (EWGSOP2), which is considered gold standard. Receiver-operating characteristic analysis was also performed to calculate the area under the curve.Results:SARC-F demonstrated high internal consistency (Cronbach’s alpha of 0.93) and excellent inter-rater and test-retest reliability, with intraclass correlation coefficient (ICC) of 0.91 (95% CI 0.79-0.96), and 0.93 (95% CI 0.91-0.95), respectively. According to the definition of sarcopenia from the EWGSOP2, 53 (26.85) participants were identified as probable sarcopenic and 23 (11.6%) as sarcopenic. Sensitivity of the tool for sarcopenia was 34.4 and specificity was 93.2. Positive predictive values were 26.4 and negative predictive values were 66.6%.Conclusion:Τhe SARC-F was successfully adapted into Greek language. The Greek SARC-F revealed low sensitivity but high specificity with EWGSOP2 sarcopenia definitions, indicating that it can detect with precision the absence of sarcopenia. 相似文献
9.
10.
Journal of Ichthyology - In this study, vertebrae, otoliths (asteriscus and lapillus), sectioned lapillus and pectoral fin rays were evaluated for age determination of Silurus glanis L., 1758... 相似文献