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91.
Maintenance of differentiated phenotype of cultured rat hepatic lipocytes by basement membrane matrix 总被引:37,自引:0,他引:37
S L Friedman F J Roll J Boyles D M Arenson D M Bissell 《The Journal of biological chemistry》1989,264(18):10756-10762
This study examined the role of extracellular matrix in regulating matrix phenotype of hepatic lipocytes, the major source of matrix in liver. Lipocytes (Ito, stellate, or fat-storing cells) were purified from normal rat liver and established in primary culture on either uncoated plastic, plastic coated with individual matrix proteins, or a "complete" gel matrix, a basement membrane-like matrix derived from the Engelbreth-Holm-Swarm (EHS) murine tumor. The ultrastructure of lipocytes cultured on the gel matrix resembled that of cells in normal liver, whereas lipocytes on plastic had dispersed nuclear chromatin and expanded rough endoplasmic reticulum, consistent with active proliferation and secretion. Lipocytes on the gel matrix exhibited no proliferative activity; cells maintained on plastic proliferated and produced type I collagen predominantly. Total collagen secretion by lipocytes on the gel matrix was 29% of that of cells on plastic, and consisted of type III collagen only. This difference extended to proteoglycan production, which was less than 5% of the amount produced by cells in conventional culture on plastic. The effects of the EHS gel were not reproduced by the individual components of the gel (laminin, type IV collagen, and heparan sulfate proteoglycan) or by a type I collagen gel. They were also reversible upon transfer of the cells to conventional culture. In contrast to lipocytes, collagen synthesis by hepatocytes was similar whether cultured on EHS gel or on plastic. These results show that the extracellular matrix can modulate matrix protein production by lipocytes and imply that, in early hepatic inflammation, changes in the hepatic subendothelial matrix may underlie stimulation of lipocyte matrix production and progression of the fibrotic process. 相似文献
92.
Codistribution of collagen types IV and AB2 in basement membranes and mesangium of the kidney. an immunoferritin study of ultrathin frozen sections 总被引:38,自引:12,他引:26 下载免费PDF全文
Affinity-purified rabbit antibodies specific for collagen types I, III, AB2 and for a partially characterized type IV collagen derived from a murine tumor were used to study the distribution of collagens in the normal mouse kidney. Immunofluorescence staining of conventional frozen sections demonstrated that types I and III were present in bundles around large vessels and in fibers surrounding glomeruli and tubules, whereas types IV and AB2 were distributed in a linear fashion along basement membranes of tubules, glomeruli, and Bowman's capsule and in the mesangial stalk. The distribution of types IV nd AB2 was examined at the ultrastructural level by staining of 600- to 800-A thick frozen sections with a three-stage procedure employing specific collagen antibodies, biotinyl sheep antirabbit IgG, and avidin-ferritin conjugates. Labeling by this procedure demonstrated codistribution of types AB2 and the putative type IV in all three basement membranes. In addition, mesangial matrix was shown to contain both of these collagen types. These results support recent biochemical evidence of collagen heterogeneity in basement membranes, and also support the concept of a structural relationship between mesangial matrix and glomerular basement membranes. 相似文献
93.
We investigated characteristics of established non-indigenous (ENI) terrestrial vertebrates in Israel and adjacent areas,
as well as attributes of areas they occupy. Eighteen non-indigenous birds have established populations in this region since
1850. A database of their attributes was compiled, analyzed, and compared to works from elsewhere. Most ENI bird species are
established locally; a few are spreading or widespread. There has been a recent large increase in establishment. All ENI birds
are of tropical origin, mostly from the Ethiopian and Oriental regions; the main families are Sturnidae, Psittacidae, Anatidae,
and Columbidae. Most species have been deliberately brought to Israel in captivity and subsequently released or escaped. Most
of these birds are commensal with humans to some degree, are not typically migratory, and have mean body mass larger than
that of the entire order. ENI birds are not distributed randomly. There are centers in the Tel-Aviv area and along the Rift
Valley, which is also a corridor of spread. Positive correlations were found between ENI bird richness and mean annual temperature
and urbanization. Mediterranean forests and desert regions have fewer ENI species than expected. Apart from birds we report
on non-indigenous species of reptiles (2) and mammals (2) in this region. 相似文献
94.
M. López‐Gómez A. Gine M.D. Vela C. Ornat F.J. Sorribas M. Talavera S. Verdejo‐Lucas 《The Annals of applied biology》2014,165(3):466-473
The relationship between the initial (Pi) and final (Pf) population densities of Meloidogyne javanica and yield of watermelon, Citrullus lanatus, cv. Sugar Baby were determined in pot and field experiments. In the pots, the maximum reproduction rate of the nematode was 14, and the equilibrium density was 49 400 eggs/100 cm3 of soil. Yield data represented as fresh top weight fitted the Seinhorst damage function (P < 0.001, R2 = 0.7), and the minimum relative yield (m) was 0.65 at Pi ≥ 3200 eggs/100 cm3 of soil and the tolerance limit (T) 74 eggs/100 cm3. In the field experiments (2011 and 2012), the maximum reproduction rate was 73 and 70, and the equilibrium density 32 and 35 second‐stage juveniles (J2)/100 cm3 soil. Yield data represented as fruit weight fitted the Seinhorst damage function in 2011 (P < 0.001, R2 = 0.92) and the m‐ and T‐values were 0.63 and 20 J2/100 cm3 of soil, respectively. Meloidogyne incognita and M. javanica needed similar length of time for development to egg‐laying females and life cycle completion at 24.4°C. 相似文献
95.
Few comprehensive works have investigated non-indigenous snails and slugs as a group. We compiled a database of non-indigenous
gastropods in Israel to explore how they arrived and spread, characteristics of their introduction, and their biological traits.
Fifty-two species of introduced gastropods are known from Israel (of which nine species subsequently went extinct): 19 species
of freshwater snails and 33 species of terrestrial gastropods. The majority of these species are found only in human-dominated
habitats. Most of those found in natural habitats are aquatic species. Most snails are introduced unintentionally from various
parts of the Holoarctic region, reaching Israel as stowaways with horticultural imports and the aquarium trade, but some are
brought intentionally to be used as pets or for food. Because the study of this group in Israel is very limited, information
regarding their distribution in the country and their effects on other species is incomplete. Though only nine species of
non-indigenous snails have been found to date in natural habitats, some of these are very abundant. More information and research
is required to enable effective management schemes. 相似文献
96.
Anne Friesgaard Christensen Grith Lykke Sørensen Kim Hørslev-Petersen Uffe Holmskov Hanne Merete Lindegaard Kirsten Junker Merete Lund Hetland Kristian Stengaard-Pedersen Søren Jacobsen Tine Lottenburger Torkell Ellingsen Smedegaard Lis Andersen Ib Hansen Henrik Skjødt Jens Kristian Pedersen Ulrik Birk Lauridsen Anders Svendsen Ulrik Tarp Jan Pødenphant Aage Vestergaard Anne Grethe Jurik Mikkel Østergaard Peter Junker 《Arthritis research & therapy》2010,12(2):1-9
Introduction
Surfactant protein D (SP-D) is a collectin with immuno-regulatory functions, which may depend on oligomerization. Anti-microbial and anti-inflammatory properties have been attributed to multimeric SP-D variants, while trimeric subunits per se have been suggested to enhance inflammation. Previously, we reported low circulating SP-D in early rheumatoid arthritis (RA), and the present investigation aims to extend these data by serial SP-D serum measurements, studies on synovial fluid, SP-D size distribution and genotyping in patients with early RA.Methods
One-hundred-and-sixty disease-modifying antirheumatic drug (DMARD) naïve RA patients with disease duration less than six months were studied prospectively for four years (CIMESTRA (Ciclosporine, Methotrexate, Steroid in RA) trial) including disease activity measures (C-reactive protein, joint counts and Health Assessment Questionnaire (HAQ) score), autoantibodies, x-ray findings and SP-D. SP-D was quantified by enzyme-linked immunosorbent assay (ELISA) and molecular size distribution was assessed by gel filtration chromatography. Further, SP-D Met11Thr single nucleotide polymorphism (SNP) analysis was performed.Results
Serum SP-D was significantly lower in RA patients at baseline compared with healthy controls (P < 0.001). SP-D increased slightly during follow-up (P < 0.001), but was still subnormal at four years after adjustment for confounders (P < 0.001). SP-D in synovial fluid was up to 2.5-fold lower than in serum. While multimeric variants were detected in serum, SP-D in synovial fluid comprised trimeric subunits only. There were no significant associations between genotype distribution and SP-D. Baseline SP-D was inversely associated to CRP and HAQ score. A similar relationship was observed regarding temporal changes in SP-D and CRP (zero to four years). SP-D was not associated to x-ray findings.Conclusions
This study confirms that circulating SP-D is persistently subnormal in early and untreated RA despite a favourable therapeutic response obtained during four years of follow-up. SP-D correlated negatively to disease activity measures, but was not correlated with x-ray progression or SP-D genotype. These observations suggest that SP-D is implicated in RA pathogenesis at the protein level. The exclusive presence of trimeric SP-D in affected joints may contribute to the maintenance of joint inflammation.Trial registration
(j.nr NCT00209859). 相似文献97.
98.
Effect of Ca2+, Ba2+, and Sr2+ on alginate microbeads 总被引:7,自引:0,他引:7
Microcapsules of alginate cross-linked with divalent ions are the most common system for cell immobilization. In this study, we wanted to characterize the effect of different alginates and cross-linking ions on important microcapsule properties. The dimensional stability and gel strength increased for high-G alginate gels when exchanging the traditional Ca2+ ions with Ba2+. The use of Ba2+ decreased the size of alginate beads and reduced the permeability to immunoglobulin G. Strontium gave gels with characteristics lying between calcium and barium. Interestingly, high-M alginate showed an opposite behavior in combination with barium and strontium as these beads were larger than beads of calcium-alginate and tended to swell more, also resulting in increased permeability. Binding studies revealed that different block structures in the alginate bind the ions to a different extent. More specifically, Ca2+ was found to bind to G- and MG-blocks, Ba2+ to G- and M-blocks, and Sr2+ to G-blocks solely. 相似文献
99.
Dentini M Caucci D Barbetta A Crescenzi V Skjåk-Braek G Capitani D Mannina L Viel S 《Biomacromolecules》2006,7(1):54-63
Galactose depleted locust bean gum was selectively oxidized in C(6) position and epimerized with mannuronan C(5)-epimerases to obtain the corresponding artificial uronanes. These new pseudo-alginates were characterized by NMR spectroscopy and circular dichroism (CD). Specifically, 1D and 2D NMR techniques allowed the degree of epimerization, the distribution of mannuronic and guluronic acid residues in the polysaccharidic chain, and the average G block length to be determined. In addition, NMR diffusion experiments showed that the epimerization reaction did not significantly degrade the polysaccharidic chains. Circular dichroism was used to investigate the kinetics of the epimerization reaction and to evidence the specific interaction between the epimerized locust bean samples with Ca(II) ions in dilute solution. All of the samples considered in this study form wall to wall gels in concentrated polymer solutions. 相似文献
100.
Roll P Sanlaville D Cillario J Labalme A Bruneau N Massacrier A Délepine M Dessen P Lazar V Robaglia-Schlupp A Lesca G Jouve E Rudolf G Rochette J Lathrop GM Szepetowski P 《PloS one》2010,5(10):e13750