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61.
Blaney Davidson EN Scharstuhl A Vitters EL van der Kraan PM van den Berg WB 《Arthritis research & therapy》2005,7(6):R1338-R1347
Osteoarthritis (OA) is a common joint disease, mainly effecting the elderly population. The cause of OA seems to be an imbalance
in catabolic and anabolic factors that develops with age. IL-1 is a catabolic factor known to induce cartilage damage, and
transforming growth factor (TGF)-beta is an anabolic factor that can counteract many IL-1-induced effects. In old mice, we
observed reduced responsiveness to TGF-beta-induced IL-1 counteraction. We investigated whether expression of TGF-beta and
its signaling molecules altered with age. To mimic the TGF-beta deprived conditions in aged mice, we assessed the functional
consequence of TGF-beta blocking. We isolated knee joints of mice aged 5 months or 2 years, half of which were exposed to
IL-1 by intra-articular injection 24 h prior to knee joint isolation. Immunohistochemistry was performed, staining for TGF-beta1,
-2 or -3, TGF-betaRI or -RII, Smad2, -3, -4, -6 and -7 and Smad-2P. The percentage of cells staining positive was determined
in tibial cartilage. To mimic the lack of TGF-beta signaling in old mice, young mice were injected with IL-1 and after 2 days
Ad-LAP (TGF-beta inhibitor) or a control virus were injected. Proteoglycan (PG) synthesis (35S-sulfate incorporation) and PG content of the cartilage were determined. Our experiments revealed that TGF-beta2 and -3 expression
decreased with age, as did the TGF-beta receptors. Although the number of cells positive for the Smad proteins was not altered,
the number of cells expressing Smad2P strongly dropped in old mice. IL-1 did not alter the expression patterns. We mimicked
the lack of TGF-beta signaling in old mice by TGF-beta inhibition with LAP. This resulted in a reduced level of PG synthesis
and aggravation of PG depletion. The limited response of old mice to TGF-beta induced-IL-1 counteraction is not due to a diminished
level of intracellular signaling molecules or an upregulation of intracellular inhibitors, but is likely due to an intrinsic
absence of sufficient TGF-beta receptor expression. Blocking TGF-beta distorted the natural repair response after IL-1 injection.
In conclusion, TGF-beta appears to play an important role in repair of cartilage and a lack of TGF-beta responsiveness in
old mice might be at the root of OA development. 相似文献
62.
Małgorzata Szymczak-Żyła Brygida Wawrzyniak-Wydrowska Grażyna Kowalewska 《Hydrobiologia》2006,554(1):155-164
The transformation of chlorophyll a by two benthic bivalves – Dreissena polymorpha and Mytilus edulis and, for comparison, by the chironomid Chironomus plumosus – was examined. D. polymorpha is a suspension-feeding, freshwater but very salinity-tolerant species, M. edulis a suspension-feeding marine species, and C.␣plumosus a typical detritivorous freshwater species. All three are common in the Odra Estuary. Specimens of the three species were
collected from this area in the period 1999–2003. The bivalves were transferred to a compartment on land and kept in tanks
filled with water (filtered and unfiltered) collected simultaneously with the organisms, under light and temperature conditions
similar to those obtaining in their natural environment. Pigments in the water samples, faeces and pseudofaeces from the tanks,
and in the gut content from C. plumosus, were determined with HPLC. The digestion products of the three species were mainly phaeophorbides a, generally thought to originate mainly from zooplankton grazing, and pyrophaeophytin a in minor quantities. The results indicate that the main chlorophyll a derivatives in faeces and pseudofaeces and gut content of the three species were the same as those in the sediments of the
Baltic Sea, including the Odra Estuary. Our previous studies have shown that the sediments in this area are richer in phaeophorbides
a than sediments from other parts of the southern Baltic Sea. All this suggests that the benthos may play an important role
in the transformation of chlorophyll a in the Odra Estuary area. 相似文献
63.
During the last decades, farmland habitats in central European countries have changed significantly, seriously affecting populations of many farmland bird species. We compiled available published data on densities of three owl species, Athene noctua, Asio otus and Strix aluco collected in the Polish farmland. All results of censuses based on the playback method conducted between 1980–2005 were included in the analysis. The proportions of grassland, fields, built-up land and forest at each studied plot were estimated and used as predictors in additive models. Proportions of main land use types, extracted with the principal component analysis, explained much of the variation found in owl densities, although some of the relationships were nonlinear. In general, owl densities were found to be affected positively by a high percentage of grasslands and built-up land, and negatively by the amount of fields and forests. Little owl densities showed a significant negative trend over the study period. It seems that high prey availability is an important factor accounting for the positive relationship between grassland proportion and owl density. The significant decrease in grassland areas and increase in forest coverage that were recently recorded in Poland may thus negatively affect populations of the three owl species studied here. 相似文献
64.
Rafał Jakub Bułdak Renata Polaniak Łukasz Bułdak Krystyna Żwirska‐Korczala Magdalena Skonieczna Aleksandra Monsiol Michał Kukla Anna Duława‐Bułdak Ewa Birkner 《Bioelectromagnetics》2012,33(8):641-651
The aim of this study was to assess the influence of cisplatin and an extremely low frequency electromagnetic field (ELF‐EMF) on antioxidant enzyme activity and the lipid peroxidation ratio, as well as the level of DNA damage and reactive oxygen species (ROS) production in AT478 carcinoma cells. Cells were cultured for 24 and 72 h in culture medium with cisplatin. Additionally, the cells were irradiated with 50 Hz/1 mT ELF‐EMF for 16 min using a solenoid as a source of the ELF‐EMF. The amount of ROS, superoxide dismutase (SOD) isoenzyme activity, glutathione peroxidase (GSH‐Px) activity, DNA damage, and malondialdehyde (MDA) levels were assessed. Cells that were exposed to cisplatin exhibited a significant increase in ROS and antioxidant enzyme activity. The addition of ELF‐EMF exposure to cisplatin treatment resulted in decreased ROS levels and antioxidant enzyme activity. A significant reduction in MDA concentrations was observed in all of the study groups, with the greatest decrease associated with treatment by both cisplatin and ELF‐EMF. Cisplatin induced the most severe DNA damage; however, when cells were also irradiated with ELF‐EMF, less DNA damage occurred. Exposure to ELF‐EMF alone resulted in an increase in DNA damage compared to control cells. ELF‐EMF lessened the effects of oxidative stress and DNA damage that were induced by cisplatin; however, ELF‐EMF alone was a mild oxidative stressor and DNA damage inducer. We speculate that ELF‐EMF exerts differential effects depending on the exogenous conditions. This information may be of value for appraising the pathophysiologic consequences of exposure to ELF‐EMF. Bioelectromagnetics 33:641–651, 2012. © 2012 Wiley Periodicals, Inc. 相似文献
65.
Waszkiewicz N Szajda SD Zalewska A Szulc A Kępka A Minarowska A Wojewódzka-Żelezniakowicz M Konarzewska B Chojnowska S Ladny JR Zwierz K 《Folia histochemica et cytobiologica / Polish Academy of Sciences, Polish Histochemical and Cytochemical Society》2012,50(1):1-11
The relationship between alcohol consumption and glycoconjugate metabolism is complex and multidimensional. This review summarizes the advances in basic and clinical research on the molecular and cellular events involved in the metabolic effects of alcohol on glycoconjugates (glycoproteins, glycolipids, and proteoglycans). We summarize the action of ethanol, acetaldehyde, reactive oxygen species (ROS), nonoxidative metabolite of alcohol--fatty acid ethyl esters (FAEEs), and the ethanol-water competition mechanism, on glycoconjugate biosynthesis, modification, transport and secretion, as well as on elimination and catabolism processes. As the majority of changes in the cellular metabolism of glycoconjugates are generally ascribed to alterations in synthesis, transport, glycosylation and secretion, the degradation and elimination processes, of which the former occurs also in extracellular matrix, seem to be underappreciated. The pathomechanisms are additionally complicated by the fact that the effect of alcohol intoxication on the glycoconjugate metabolism depends not only on the duration of ethanol exposure, but also demonstrates dose- and regional-sensitivity. Further research is needed to bridge the gap in transdisciplinary research and enhance our understanding of alcohol- and glycoconjugate-related diseases. 相似文献
66.
The present study analyzed binding of Cu2+ to tetrapeptides in water solution at several levels of theoretical approximation. The methods used to study the energetic
and structural properties of the complexes in question include semiempirical hamiltonians, density functional theory as well
as ab initio approaches including electron correlation effects. In order to shed light on the character of interactions between
Cu2+ and peptides, which are expected to be mainly electrostatic in nature, decomposition of interaction energy into physically
meaningful components was applied. 相似文献
67.
68.
Iwona Żur Andrzej Skoczowski Sebastian Pieńkowski Franciszek Dubert 《Acta Physiologiae Plantarum》2002,24(1):11-17
The uptake rate of 14C-labelled sucrose, myo-inositol and PC was studied in callus cultures of two oilseed rape cultivars, characterized by different in vitro regeneration ability. Transfer of calli onto regeneration stimulating medium resulted in changes of examined substances uptake
rate, which were depended on tissue morphogenic potential. Non-regenerating calli of both cultivars increased uptake rate
of sucrose whereas changes in incorporation of other compounds were under genome control. Significant increase of uptake rate
of all tested compounds was observed as result of organogenesis initiation. Such differences, in the responses of organogenic
and non-organogenic tissue indicate that this parameter could be useful as marker of organogenesis
A correlation was observed between the rate of sucrose uptake and its concentration in the medium, which suggests an advantage
to passive transport through the callus cell membrane. Lack of such correlation in the case of other labels indicates that
this processes are selective and under cell control. 相似文献
69.
Żur Iwona Skoczowski Andrzej Niemczyk Elżbieta Dubert Franciszek 《Acta Physiologiae Plantarum》2002,24(1):3-10
Changes in the membrane lipid and sterols content and composition were studied during induction and differentiation in callus
cultures of Brassica napus var. oleifera. Callus induction was associated with an increase of DGDG content, significant changes in fatty acids composition of all
lipid fractions and increased degree of lipid unsaturation. The membrane lipid composition of tissue at different degrees
of differentiation was found to vary significantly, particularly two weeks after transfer of callus to regeneration medium.
The main differences concerned the content and composition of galactolipids. Curiously in many cases, these differences declined
during subsequent culture, in spite of the morphogenesis process which was in progress. Another result of differentiation
was the change in free sterol composition: in shoot regenerating calli the content of stigmasterol had rose whereas the accumulation
of campesterol decreased. Even though observed changes in membrane properties may not play a role in morphogenesis they are
nevertheless useful as developmental markers and can be invaluable in understanding biochemical basis of morphogenesis. 相似文献
70.
Does a heavy fruit crop reduce the tree ring increment? Results from a 12-year study in a subalpine zone 总被引:1,自引:0,他引:1
Life history theory posits that an increased investment in reproduction should result in decreased vegetative investment. Switching resources from growth to reproduction are also expected in species experiencing selection pressure for high variation of seed crops. In this study, we tested whether the reproductive effort of trees, measured as the number of fruits produced, is related to their radial growth increment. We examined a population of Sorbus aucuparia, a fleshy-fruited tree species with highly variable interannual individual fruit production growing in the subalpine zone and under strong selection pressure from pre-dispersal seed predators. We used 12-year data to test the relationship between fruit crop and radial growth increments in current, previous and subsequent years, and found no trade-off between growth and reproduction. For almost all trees, there was no correlation between fruit crop and radial growth increment in the same year or next year. Only a few trees showed a positive correlation between fruit crop and previous-year growth. In the statistics, we took advantage of the high variability of individual fruit crops in high production years. In four heavy crop years, we compared the radial growth increments of trees with heavy crops with those of trees with low fruit crops. Current and next-year radial growth did not differ between trees with low and high fruit crops. In all those years, however, trees having heavy fruit crops had higher previous-year growth increments. We suggest that the harsh subalpine weather conditions account for the lack of a trade-off between growth and reproduction in the studied population. 相似文献