排序方式: 共有61条查询结果,搜索用时 15 毫秒
31.
Serene M. L. Lee Celine Schelcher Rüdiger P. Laubender Natalja Fr?se Reinhard M. K. Thasler Tobias S. Schiergens Ulrich Mansmann Wolfgang E. Thasler 《PloS one》2014,9(10)
Isolated human primary hepatocytes are an essential in vitro model for basic and clinical research. For successful application as a model, isolated hepatocytes need to have a good viability and be available in sufficient yield. Therefore, this study aims to identify donor characteristics, intra-operative factors, tissue processing and cell isolation parameters that affect the viability and yield of human hepatocytes. Remnant liver pieces from tissue designated as surgical waste were collected from 1034 donors with informed consent. Human hepatocytes were isolated by a two-step collagenase perfusion technique with modifications and hepatocyte yield and viability were subsequently determined. The accompanying patient data was collected and entered into a database. Univariate analyses found that the viability and the yield of hepatocytes were affected by many of the variables examined. Multivariate analyses were then carried out to confirm the factors that have a significant relationship with the viability and the yield. It was found that the viability of hepatocytes was significantly decreased by the presence of fibrosis, liver fat and with increasing gamma-glutamyltranspeptidase activity and bilirubin content. Yield was significantly decreased by the presence of liver fat, septal fibrosis, with increasing aspartate aminotransferase activity, cold ischemia times and weight of perfused liver. However, yield was significantly increased by chemotherapy treatment. In conclusion, this study determined the variables that have a significant effect on the viability and the yield of isolated human hepatocytes. These variables have been used to generate an algorithm that can calculate projected viability and yield of isolated human hepatocytes. In this way, projected viability can be determined even before isolation of hepatocytes, so that donors that result in high viability and yield can be identified. Further, if the viability and yield of the isolated hepatocytes is lower than expected, this will highlight a methodological problem that can be addressed. 相似文献
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Natalja Genina Heikki Räikkönen Jyrki Heinämäki Peep Veski Jouko Yliruusi 《AAPS PharmSciTech》2010,11(2):959-965
We nano-coated powdered lactose particles with the enzyme β-galactosidase using an ultrasound-assisted technique. Atomization
of the enzyme solution did not change its activity. The amount of surface-attached β-galactosidase was measured through its
enzymatic reaction product D-galactose using a standardized method. A near-linear increase was obtained in the thickness of
the enzyme coat as the treatment proceeded. Interestingly, lactose, which is a substrate for β-galactosidase, did not undergo
enzymatic degradation during processing and remained unchanged for at least 1 month. Stability of protein-coated lactose was
due to the absence of water within the powder, as it was dry after the treatment procedure. In conclusion, we were able to
attach the polypeptide to the core particles and determine precisely the coating efficiency of the surface-treated powder
using a simple approach. 相似文献
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Vladimir Chekulayev Kati Mado Igor Shevchuk Andre Koit Andrus Kaldma Aleksandr Klepinin Natalja Timohhina Kersti Tepp Manana Kandashvili Lyudmila Ounpuu Karoliina Heck Laura Truu Anu Planken Vahur Valvere Tuuli Kaambre 《Biochemistry and Biophysics Reports》2015
The aim of the work was to evaluate whether or not there is glycolytic reprogramming in the neighboring cells of colorectal cancer (CRC). Using postoperative material we have compared the functional capacity of oxidative phosphorylation (OXPHOS) in CRC cells, their glycolytic activity and their inclination to aerobic glycolysis, with those of the surrounding and healthy colon tissue cells. Experiments showed that human CRC cannot be considered a hypoxic tumor, since the malignancy itself and cells surrounding it exhibited even higher rates of OXPHOS than healthy large intestine. The absence of acute hypoxia in colorectal carcinomas was also confirmed by their practically equal glucose-phosphorylating capacity as compared with surrounding non-tumorous tissue and by upregulation of VEGF family and their ligands. Studies indicated that human CRC cells in vivo exert a strong distant effect on the energy metabolism of neighboring cells, so that they acquire the bioenergetic parameters specific to the tumor itself. The growth of colorectal carcinomas was associated with potent downregulation of the creatine kinase system. As compared with healthy colon tissue, the tumor surrounding cells display upregulation of OXPHOS and have high values of basal and ADP activated respiration rates. Strong differences between the normal and CRC cells in the affinity of their mitochondria for ADP were revealed; the corresponding Km values were measured as 93.6±7.7 µM for CRC cells and 84.9±9.9 µM for nearby tissue; both these apparent Km (ADP) values were considerably (by almost 3 times) lower in comparison with healthy colon tissue cells (256±34 µM). 相似文献
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Anderson J Strelkowa N Stan GB Douglas T Savulescu J Barahona M Papachristodoulou A 《EMBO reports》2012,13(7):584-590
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The seasonal influenza A virus undergoes rapid evolution to escape human immune response. Adaptive changes occur primarily in antigenic epitopes, the antibody-binding domains of the viral hemagglutinin. This process involves recurrent selective sweeps, in which clusters of simultaneous nucleotide fixations in the hemagglutinin coding sequence are observed about every 4 years. Here, we show that influenza A (H3N2) evolves by strong clonal interference. This mode of evolution is a red queen race between viral strains with different beneficial mutations. Clonal interference explains and quantifies the observed sweep pattern: we find an average of at least one strongly beneficial amino acid substitution per year, and a given selective sweep has three to four driving mutations on average. The inference of selection and clonal interference is based on frequency time series of single-nucleotide polymorphisms, which are obtained from a sample of influenza genome sequences over 39 years. Our results imply that mode and speed of influenza evolution are governed not only by positive selection within, but also by background selection outside antigenic epitopes: immune adaptation and conservation of other viral functions interfere with each other. Hence, adapting viral proteins are predicted to be particularly brittle. We conclude that a quantitative understanding of influenza’s evolutionary and epidemiological dynamics must be based on all genomic domains and functions coupled by clonal interference. 相似文献
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Lemos Cruz Pamela Carqueijeiro Ines Koudounas Konstantinos Bomzan Dikki Pedenla Stander Emily Amor Abdallah Cécile Kulagina Natalja Oudin Audrey Lanoue Arnaud Giglioli-Guivarc’h Nathalie Nagegowda Dinesh A Papon Nicolas Besseau Sébastien Clastre Marc Courdavault Vincent 《Protoplasma》2023,260(2):607-624
Protoplasma - The medicinal plant Catharanthus roseus biosynthesizes many important drugs for human health, including the anticancer monoterpene indole alkaloids (MIAs) vinblastine and vincristine.... 相似文献
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The anionic protease inhibitor BWI-1 from buckwheat seeds. Kinetic properties and possible biological role 总被引:2,自引:0,他引:2
Yakov E. Dunaevsky Inna P. Gladysheva Ekaterina B. Pavlukova Galina A. Beliakova Dmitry P. Gladyshev Alla I. Papisova Natalja I. Larionova Mikhail A. Belozersky 《Physiologia plantarum》1997,101(3):483-488
Kinetic characteristics and effects on the growth of filamentous fungi of one of the main anionic protease inhibitors, BWI-1, isolated from buckwheat seeds, have been studied. The inhibition constants of bovine trypsin, chymotrypsin and cathepsin G from human granulocytes with BWI-1 were found to be 1.1, 67 and 200 n M , respectively. Analysis of the amino acid sequence of BWI-1 in the vicinity of the reactive site revealed its homology to the potato proteinase inhibitor I family. It is suggested that the inability of BWI-1 to bind elastase of human granulocytes is due to the basic nature of the amino acid residue (Arg) at the Pj position in its reactive site. It was demonstrated that BWI-1 was able to suppress the germination of the spores and the growth of the mycelium of two filamentous fungi. 相似文献