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排序方式: 共有952条查询结果,搜索用时 78 毫秒
41.
Hajizadeh S DeGroot J TeKoppele JM Tarkowski A Collins LV 《Arthritis research & therapy》2003,5(5):R234-R240
We investigated whether plasma and synovial fluid (SF) samples from patients with rheumatoid arthritis (RA) contained extracellular
mitochondrial DNA (mtDNA) or the oxidatively damaged DNA adduct 8-hydroxy-2'-deoxyguanosine (8-oxodG). Moreover, we correlated
the laboratory findings of the patients with RA with their levels of mtDNA and 8-oxodG. SF and plasma samples from 54 patients
with RA, SF from 30 non-arthritic control subjects, and plasma from 22 healthy volunteers were collected. The samples were
subjected to polymerase chain reaction (PCR) using mitochondrial genomic primers, and the products were analyzed by SDS–polyacrylamide-gel
electrophoresis. The intensities of the PCR-amplified bands were quantified and normalized to a reference sample. Furthermore,
the SF samples were assayed by enzyme-linked immunosorbent assay for 8-oxodG. Extracellular PCR-amplifiable mtDNA was detected
in the SF of 38 of 54 (70%) patients with RA, but not in any of the SF controls. PCR-amplifiable mtDNA was detected in the
plasma of 30 of 54 (56%) of patients with RA and in 6 of 22 (27%) of the healthy volunteers. The levels of mtDNA in the plasma
and SF samples of patients with RA were significantly higher (P < 0.0001) than in the respective control samples. The presence of both mtDNA and 8-oxodG in SF was significantly correlated
with the presence of rheumatoid factor in the patients with RA. Extracellular mtDNA and oxidized DNA were detected in the
SF of the great majority of patients with RA, but were absent or present at low levels in the control SF. These findings indicate
that endogenous nucleic acid compounds might participate in joint inflammation by activating immune cells in the joints to
produce proinflammatory cytokines. 相似文献
42.
Antonov VF Anosov AA Norik VP Korepanova EA Smirnova EY 《European biophysics journal : EBJ》2003,32(1):55-59
Electrical capacitance of the planar bilayer lipid membrane (BLM) formed from hydrogenated egg lecithin (HEL) has been studied during many passages through the phase transition temperature. In contrast to the BLM from individual synthetic phospholipids, membranes from HEL did not demonstrate any capacitance change at the phase transition temperature maximum, as measured by differential scanning calorimeter at 52 degrees C. Instead, two temperatures have been discerned by capacitance records: thickening at 42-43 degrees C and thinning at 57-59 degrees C. The first temperature region is close to the transition temperature of dipalmitoyllecithin, whereas the second is close to that of distearoyllecithin, two main components of the HEL. It was suggested that capacitance measurements were able to reveal a phase separation in the BLM from HEL which was not detected by differential scanning calorimetry. The phase transition of the BLM from the liquid crystal state to the gel state is followed by thickening of the bilayer structure, partly due to a gauche- trans transition of lipid molecules but mainly due to redistribution of the solvent n-decane. 相似文献
43.
Uroplakins and cytokeratins in the regenerating rat urothelium after sodium saccharin treatment 总被引:7,自引:2,他引:5
A sodium saccharin (NaSac) diet was used to induce cell damage and regeneration in the urothelium of the male rat urinary
bladder. Foci of terminally differentiated superficial cell exfoliation were detected after 5 weeks and their number increased
after 10 and 15 weeks of the diet. At the sites of superficial cell loss, regenerative simple hyperplasia developed. Within
5 weeks of NaSac removal, regeneration re-established normal differentiated urothelium. In order to follow urothelial differentiation
during regeneration we studied the expression of uroplakins and cytokeratins by means of immunocytochemistry and immunohistochemistry,
respectively. Normal urothelium was characterised by terminally differentiated superficial cells which expressed uroplakins
in their luminal plasma membrane and cytokeratin 20 (CK20) in the cytoplasm. Basal and intermediate cells were CK20 negative
and cytokeratin 17 (CK17) positive. In hyperplastic urothelium all cells synthesised CK17, but not CK20. Differentiation of
the superficial layer was reflected in three successive cell types: cells with microvilli, cells with rounded microridges
and those with a rigid-looking plasma membrane on the luminal surface. The cells with microvilli did not stain with anti-uroplakin
antibody. When the synthesis of uroplakins was detected rounded microridges were formed. With the elevated expression of uroplakins
the luminal plasma membrane becomes rigid-looking which is characteristic of asymmetric unit membrane of terminally differentiated
cells. During differentiation, syn-thesis of CK17 ceased in superficial cells while the synthesis of CK20 started. These results
indicate that during urothelial regeneration after NaSac treatment, specific superficial cell types develop in which the switch
to uroplakin synthesis and transition from CK17 to CK20 synthesis are crucial events for terminal differentiation.
Accepted: 19 August 1997 相似文献
44.
Christopher E. Anson Colin S. Creaser J.Allan Downie Orsolya Egyed Andrej V. Malkov Ljubica Mojovic G.Richard Stephenson Andrew T. Turner Karen E. Wilson 《Bioorganic & medicinal chemistry letters》1998,8(24):10883-3554
Derivatives of naringenin have been synthesized with organometalcarbonyl reporting groups for IR spectroscopy attached at C-2, C-3′, or C-6, and the products have been tested for the induction of nod gene expression using a Rhizobium leguminosarum strain which contains the Escherichia coli lacZ (β-galactosidase) gene fused to nodABC. Derivatives with an OMe substituent within the reporting group moiety showed residual gene induction activity. 相似文献
45.
Lovro ?ubelj Marko Bajec Biljana Mileva Boshkoska Andrej Kastrin Zoran Levnaji? 《PloS one》2015,10(5)
Science is a social process with far-reaching impact on our modern society. In recent years, for the first time we are able to scientifically study the science itself. This is enabled by massive amounts of data on scientific publications that is increasingly becoming available. The data is contained in several databases such as Web of Science or PubMed, maintained by various public and private entities. Unfortunately, these databases are not always consistent, which considerably hinders this study. Relying on the powerful framework of complex networks, we conduct a systematic analysis of the consistency among six major scientific databases. We found that identifying a single "best" database is far from easy. Nevertheless, our results indicate appreciable differences in mutual consistency of different databases, which we interpret as recipes for future bibliometric studies. 相似文献
46.
Amrita Roy Choudhury Emilia Sikorska Johannes van den Boom Peter Bayer ?ukasz Popenda Kosma Szutkowski Stefan Jurga Massimiliano Bonomi Andrej Sali Igor Zhukov Sabina Passamonti Marjana Novi? 《PloS one》2015,10(8)
We present a 3D model of the four transmembrane (TM) helical regions of bilitranslocase (BTL), a structurally uncharacterized protein that transports organic anions across the cell membrane. The model was computed by considering helix-helix interactions as primary constraints, using Monte Carlo simulations. The interactions between the TM2 and TM3 segments have been confirmed by Förster resonance energy transfer (FRET) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy, increasing our confidence in the model. Several insights into the BTL transport mechanism were obtained by analyzing the model. For example, the observed cis-trans Leu-Pro peptide bond isomerization in the TM3 fragment may indicate a key conformational change during anion transport by BTL. Our structural model of BTL may facilitate further studies, including drug discovery. 相似文献
47.
Ilia Ostrovski Leif E. Lovblom Mohammed A. Farooqi Daniel Scarr Genevieve Boulet Paul Hertz Tong Wu Elise M. Halpern Mylan Ngo Eduardo Ng Andrej Orszag Vera Bril Bruce A. Perkins 《PloS one》2015,10(11)
Objective
In vivo Corneal Confocal Microscopy (IVCCM) is a validated, non-invasive test for diabetic sensorimotor polyneuropathy (DSP) detection, but its utility is limited by the image analysis time and expertise required. We aimed to determine the inter- and intra-observer reproducibility of a novel automated analysis program compared to manual analysis.Methods
In a cross-sectional diagnostic study, 20 non-diabetes controls (mean age 41.4±17.3y, HbA1c 5.5±0.4%) and 26 participants with type 1 diabetes (42.8±16.9y, 8.0±1.9%) underwent two separate IVCCM examinations by one observer and a third by an independent observer. Along with nerve density and branch density, corneal nerve fibre length (CNFL) was obtained by manual analysis (CNFLMANUAL), a protocol in which images were manually selected for automated analysis (CNFLSEMI-AUTOMATED), and one in which selection and analysis were performed electronically (CNFLFULLY-AUTOMATED). Reproducibility of each protocol was determined using intraclass correlation coefficients (ICC) and, as a secondary objective, the method of Bland and Altman was used to explore agreement between protocols.Results
Mean CNFLManual was 16.7±4.0, 13.9±4.2 mm/mm2 for non-diabetes controls and diabetes participants, while CNFLSemi-Automated was 10.2±3.3, 8.6±3.0 mm/mm2 and CNFLFully-Automated was 12.5±2.8, 10.9 ± 2.9 mm/mm2. Inter-observer ICC and 95% confidence intervals (95%CI) were 0.73(0.56, 0.84), 0.75(0.59, 0.85), and 0.78(0.63, 0.87), respectively (p = NS for all comparisons). Intra-observer ICC and 95%CI were 0.72(0.55, 0.83), 0.74(0.57, 0.85), and 0.84(0.73, 0.91), respectively (p<0.05 for CNFLFully-Automated compared to others). The other IVCCM parameters had substantially lower ICC compared to those for CNFL. CNFLSemi-Automated and CNFLFully-Automated underestimated CNFLManual by mean and 95%CI of 35.1(-4.5, 67.5)% and 21.0(-21.6, 46.1)%, respectively.Conclusions
Despite an apparent measurement (underestimation) bias in comparison to the manual strategy of image analysis, fully-automated analysis preserves CNFL reproducibility. Future work must determine the diagnostic thresholds specific to the fully-automated measure of CNFL. 相似文献48.
Barbora Vidová Zuzana Šramková Lenka Tišáková Michaela Oravkinová Andrej Godány 《Biologia》2014,69(5):541-556
Endolysins as a class of antibacterial enzymes are expected to become a very useful tool for many purposes to control spreading of, e.g., multiresistant bacteria in different environments. Their antimicrobial properties could be broadened or altered by mutagenesis, domain swapping or gene shuffling. Therefore, the specific designing of endolysins to achieve their desired properties is challenging. This work is focused on the in silico analysis of protein domains presence in sequences of phage and prophage endolysins, followed by the study of variety of domain combinations in the individual endolysin types. The multiple sequence alignment of endolysin sequences revealed the recognition of sequence types with typical domain arrangement and conserved amino acids, divided according to the target substrate in bacterial cell walls. The five protein families of catalytic domains are specifically occurring in dependence of bacterial Gram-type. The presence, types and numbers of binding domains within endolysin sequences were also studied. The obtained results enable a more targeted design of endolysins with required antimicrobial properties. 相似文献
49.
Cytoplasmic dynein moves processively along microtubules, but the mechanism of how its heads use the energy from ATP hydrolysis, coupled to a linker swing, to achieve directed motion, is still unclear. In this article, we present a theoretical model based on the winch mechanism in which the principal direction of the linker stroke is toward the microtubule-binding domain. When mechanically coupling two identical heads (each with postulated elastic properties and a minimal ATPase cycle), the model reproduces stepping with 8-nm steps (even though the motor itself is much larger), interhead coordination, and processivity, as reported for mammalian dyneins. Furthermore, when we loosen the elastic connection between the heads, the model still shows processive directional stepping, but it becomes uncoordinated and the stepping pattern shows a greater variability, which reproduces the properties of yeast dyneins. Their slower chemical kinetics allows processive motility and a high stall force without the need for coordination. 相似文献
50.
Carvalho M Schwudke D Sampaio JL Palm W Riezman I Dey G Gupta GD Mayor S Riezman H Shevchenko A Kurzchalia TV Eaton S 《Development (Cambridge, England)》2010,137(21):3675-3685
The high sterol concentration in eukaryotic cell membranes is thought to influence membrane properties such as permeability, fluidity and microdomain formation. Drosophila cannot synthesize sterols, but do require them for development. Does this simply reflect a requirement for sterols in steroid hormone biosynthesis, or is bulk membrane sterol also essential in Drosophila? If the latter is true, how do they survive fluctuations in sterol availability and maintain membrane homeostasis? Here, we show that Drosophila require both bulk membrane sterol and steroid hormones in order to complete adult development. When sterol availability is restricted, Drosophila larvae modulate their growth to maintain membrane sterol levels within tight limits. When dietary sterol drops below a minimal threshold, larvae arrest growth and development in a reversible manner. Strikingly, membrane sterol levels in arrested larvae are dramatically reduced (dropping sixfold on average) in most tissues except the nervous system. Thus, sterols are dispensable for maintaining the basic membrane biophysical properties required for cell viability; these functions can be performed by non-sterol lipids when sterols are unavailable. However, bulk membrane sterol is likely to have essential functions in specific tissues during development. In tissues in which sterol levels drop, the overall level of sphingolipids increases and the proportion of different sphingolipid variants is altered. These changes allow survival, but not growth, when membrane sterol levels are low. This relationship between sterols and sphingolipids could be an ancient and conserved principle of membrane homeostasis. 相似文献