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排序方式: 共有336条查询结果,搜索用时 31 毫秒
131.
132.
Daniela Curti Emanuela Izzo Liliana Brambilla Giovanna Facchetti Giovanni Sangiovanni Gianluigi Brambilla 《Neurochemical research》1995,20(9):1001-1006
Persistent stimulation of energy consumption, induced by depolarization with veratridine, mimics a condition of abnormally enhanced energy demand and causes an increase in the oxygen consumption rate (QO2) and in the interconversion of pyruvate dehydrogenase complex (PDHc) into its active form. Wistar rats at the age of 26 months do not show alterations of QO2 and of the ability of veratridine to increase QO2 in comparison with 6 month-old animals whereas the active form of PDHc is slightly but significantly reduced. Idebenone, a ubiquinone-like molecule (1 M), does not affect the QO2 or PDHc activation state in resting conditions but attenuates the veratridine-challenged increase in QO2 at all the ages tested and attenuates the increase in the percentage of PDHa reaching statistical significance in 26-month-old rats. At higher concentration (10 M) idebenone totally abolishes the veratridine-induced increase in PDHa also in the 6 month-old rats. At the lower concentration, the drug does not affect the increase in QO2 induced by an uncoupler of oxidative phosphorylation. The results obtained suggest a protective effect of idebenone on the cerebral tissue against stressful conditions; this action may be exerted at the level of some mitochondrial component and/or on the Na+ homeostasis. 相似文献
133.
Three years of experience in biomanipulating a small eutrophic lake: Lago di Candia (Northern Italy) 总被引:1,自引:1,他引:0
Results obtained from a step by step approach to the biomanipulation of a natural lacustrine environment (Lago di Candia,
Northern Italy) are presented. Since the diversion of the municipal sewage of the small town of Candia, runoff and precipitation
have been the sole contributors of nutrient to the lake. Fish population is mainly characterized by rudd (Scardinius erythrophthalmus) overstocking and by a low density of large-mouth-bass (Micropterus salmoides) and pike (Esox lucius). During 1986 about 12t of rudd (1–2 year old) were removed from the lake. Considering 1986 as ‘control year’, average Secchi disc transparency improved
from 2.3 m in 1986 to 3.3 m in 1988; phytoplankton biovolume decreased from 114 to 58 mm3 l−1 but zooplankton biovolume increased from 8 to 11.5 mm3 l−1. The results achieved show that a grodual biomanipulation treatment can have a satisfactory outcome, and has the advantage
of not producing catastrophic situations either in the biotic or in the abiotic compartments of the lake. 相似文献
134.
Gabriella Sandri Gianluigi Sottocasa Enrico Panfili Gianfranco Liut 《生物化学与生物物理学报:生物膜》1979,558(2):214-220
Rat liver mitochondria may be subfractionated in sediment and supernatant fractions by swelling in the presence of EDTA and oxaloacetate. The sediment is largely depleted of the Ca2+-binding glycoprotein and its Ca2+-transporting activity may be as low as 10–20% of the starting value. Both the rate of Ca2+ uptake and the capacity to maintain a high Ca2+ concentration gradient across the membrane are depressed. Addition of an osmotic supernatant to the assay mixture may partially restore the original Ca2+-transporting ability. The active component in the supernatant is the Ca2+-binding glycoprotein. This is shown by the following facts: (a) the effect is enhanced by the addition of the purified glycoprotein to the supernatant; (b) precipitation of the glycoprotein from the supernatant by affinity chromatography-purified antibodies abolishes the stimulatory effect, and (c) in the presence of 130 μM Mg2+, the glycoprotein alone may restore fully the Ca2+-transporting ability of the particles. The maximal velocity is already reached at 0.1 μg glycoprotein/mg mitochondrial protein. 相似文献
135.
Napoli N Giannelli G Parisi CV Antonaci A Maddalena G Antonaci S 《The new microbiologica》2005,28(1):13-21
Early virological response (EVR) to different interferon-based regimens plus ribavirin and its ability to predict the outcome of therapy in patients with chronic hepatitis C were investigated. The study design was as follows: 64 naive patients were considered, 32/64 received pegylated interferon alpha-2b (Peg-IFN-alpha2b) plus ribavirin and the remaining 32 received leucocyte interferon alpha (IFN-alpha) plus ribavirin. At week 4 of treatment, EVR was present in 68.7% and 37.5% of patients treated with Peg-IFN-alpha2b plus ribavirin, and with leucocyte interferon alpha (IFN-alpha) plus ribavirin, respectively (p = 0.024). At week 12, the cumulative EVR rates did not differ between the two groups (71.9% vs 56.2%, p >0.05) because a higher proportion of patients achieved EVR for the first time after more than 4 weeks of therapy in the standard IFN-alpha group. Sustained virological response (SVR) rates, however, resulted significantly higher in the Peg-IFN-alpha2b group (65.6% vs 37.5%; p = 0.045) since a higher proportion of patients who received standard IFN-alpha relapsed during the follow-up. In the standard IFN-alpha group, HCV genotype 1 (p = 0.035), high baseline viral load (p = 0.035) and the presence of bridging fibrosis/cirrhosis (p = 0.011) were closely associated with significantly lower SVR rates. In the Peg-IFN-alpha2b group, only bridging fibrosis/cirrhosis (p = 0.02) negatively influenced the outcome of treatment. Overall, 33/41 (80.5%) patients with EVR at week 12 were sustained responders, yielding a positive predictive value (PPV) of 0.80. However, when SVR was related to the time taken to reach EVR, 32/34 (94.1%) patients with EVR at week 4 of therapy (PPV = 0.94) versus 1/7 (14.3%) patients who had EVR after more than 4 weeks of therapy (PPV = 0.14) resulted sustained responders (p = 0.000057). In conclusion, EVR at week 4 of treatment is strongly associated with the likelihood of achieving SVR, regardless of the therapeutic regimen. However, when compared with standard IFN-alpha plus ribavirin, treatment with Peg-IFN-alpha2b plus ribavirin significantly increases the probability of viral clearance within the first 4 weeks of treatment. Finally, patients who do not clear the virus within the first 12 weeks of treatment have no chance of achieving SVR, justifying discontinuation of therapy in these patients. 相似文献
136.
(1)H/(15)N heteronuclear NMR spectroscopy shows four dynamic domains for phospholamban reconstituted in dodecylphosphocholine micelles
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We report the backbone dynamics of monomeric phospholamban in dodecylphosphocholine micelles using (1)H/(15)N heteronuclear NMR spectroscopy. Phospholamban is a 52-amino acid membrane protein that regulates Ca-ATPase in cardiac muscle. Phospholamban comprises three structural domains: a transmembrane domain from residues 22 to 52, a connecting loop from 17 to 21, and a cytoplasmic domain from 1 to 16 that is organized in an "L"-shaped structure where the transmembrane and the cytoplasmic domain form an angle of approximately 80 degrees (Zamoon et al., 2003; Mascioni et al., 2002). T(1), T(2), and (1)H/(15)N nuclear Overhauser effect values measured for the amide backbone resonances were interpreted using the model-free approach of Lipari and Szabo. The results point to the existence of four dynamic domains, revealing the overall plasticity of the cytoplasmic helix, the flexible loop, and part of the transmembrane domain (residues 22-30). In addition, using Carr-Purcell-Meiboom-Gill-based experiments, we have characterized phospholamban dynamics in the micros-ms timescale. We found that the majority of the residues in the cytoplasmic domain, the flexible loop, and the first ten residues of the transmembrane domain undergo dynamics in the micros-ms range, whereas minimal dynamics were detected for the transmembrane domain. Hydrogen/deuterium exchange factors measured at different temperatures support the existence of slow motion in both the loop and the cytoplasmic helix. We propose that these dynamic properties are critical factors in the biomolecular recognition of phospholamban by Ca-ATPase and other interacting proteins such as protein kinase A and protein phosphatase 1. 相似文献
137.
Stefano Managò Peppino Mirabelli Michela Napolitano Gianluigi Zito Anna C. De Luca 《Journal of biophotonics》2018,11(5)
The analysis of leukocytes of peripheral blood is a crucial step in hematologic exams commonly used for disease diagnosis and, typically, requires molecular labelling. In addition, only a detailed, laborious phenotypic analysis allows identifying the presence and stage of specific pathologies such as leukemia. Most of the biochemical information is lost in the routine blood tests. In the present study, we tackle 2 important issues of label‐free biochemical identification and classification of leukocytes using Raman spectroscopy (RS). First, we demonstrate that leukocyte subpopulations of lymphocytes (B, T and NK cells), monocytes and granulocytes can be identified by the unsupervised statistical approach of principal component analysis and classified by linear discriminant analysis with approximately 99% of accuracy. Second, we apply the same procedure to identify and discriminate normal B cells and transformed MN60 lymphocyte leukemic cell lines. In addition, we demonstrate that RS can be efficiently used for monitoring the cell response to low‐dose chemotherapy treatment, experimentally eliciting the sensitivity to a dose‐dependent cell response, which is of fundamental importance to determine the efficacy of any treatment. These results largely expand established Raman‐based research protocols for label‐free analysis of white blood cells, leukemic cells and chemotherapy treatment follow‐up. 相似文献
138.
139.
Paolo Rossi Youlin Xia Nandish Khanra Gianluigi Veglia Charalampos G. Kalodimos 《Journal of biomolecular NMR》2016,66(4):259-271
The ongoing NMR method development effort strives for high quality multidimensional data with reduced collection time. Here, we apply ‘SOFAST-HMQC’ to frequency editing in 3D NOESY experiments and demonstrate the sensitivity benefits using highly deuterated and 15N, methyl labeled samples in H2O. The experiments benefit from a combination of selective T 1 relaxation (or L-optimized effect), from Ernst angle optimization and, in certain types of experiments, from using the mixing time for both NOE buildup and magnetization recovery. This effect enhances sensitivity by up to 2.4× at fast pulsing versus reference HMQC sequences of same overall length and water suppression characteristics. Representative experiments designed to address interesting protein NMR challenges are detailed. Editing capabilities are exploited with heteronuclear 15N,13C-edited, or with diagonal-free 13C aromatic/methyl-resolved 3D-SOFAST-HMQC–NOESY–HMQC. The latter experiment is used here to elucidate the methyl-aromatic NOE network in the hydrophobic core of the 19 kDa FliT-FliJ flagellar protein complex. Incorporation of fast pulsing to reference experiments such as 3D-NOESY–HMQC boosts digital resolution, simplifies the process of NOE assignment and helps to automate protein structure determination. 相似文献
140.