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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of IH764-3, a potent component isolated from Salvia miltiorrhiza, on the proliferation and function of cultured fibroblasts was studied. It was found that the fibroblast growth curve had a dose-dependent relationship with IH764-3 concentration. The incorporation of 3H-TdR and 3H-proline into fibroblasts was significantly inhibited by IH764-3, and calmodulin, fibronectin and thrombospondin contents in the test group were obviously lower than those in the control group. Flow cytometry showed that in the IH764-3-treated group, the percentage of cells in G0/G1 phase was higher than that in the control. Electron microscopic observation (TEM and SEM) showed that in the treated group, collagen secretion was decreased. All of these results indicate that IH764-3 exerts a direct inhibitory effect on fibroblast proliferation and affects their ability to synthesize collagen.
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PMID:The effect of IH764-3 on fibroblast proliferation and function. 128 82

Fibronectin (Fn), an acute phase glycoprotein synthesized by the liver, has an important immunomodulatory role. We have investigated the changes in plasma Fn in patients after renal transplantation in order to determine whether these changes predict graft injury or rejection episodes. Besides normal healthy controls, healthy pregnant controls, and a trauma control group, we used two groups of chronic renal failure patients as controls: group I, patients with end-stage renal failure (ESRF) on peritoneal dialysis; group II, patients with ESRF on hemodialysis. These were compared with two groups of renal transplant patients: group III, patients 3 months after successful renal transplantation; group IV, patients studied sequentially 10 days immediately posttransplantation. The renal transplant patients were treated with low-dose cyclosporine, azathioprine, and steroids. Citrated plasma samples were collected for Fn assay by a sandwich-type ELISA and for SDS-PAGE analysis and Western blotting. The mean plasma Fn levels were as follows: healthy controls 311.6 SEM, 13.5 micrograms/ml; healthy pregnant controls 357 SEM, 5.9 micrograms/ml; trauma controls 262.3 SEM 31.7, micrograms/ml; group I 169 SEM, 25.1 micrograms/ml; group II 199 SEM, 27.2 micrograms/ml; group III 272 SEM, 21.7 micrograms/ml; group IV 212 SEM, 27.4 micrograms/ml (day 3 postop). There was a significant difference in the plasma Fn levels on day 3 posttransplant between the patients with delayed and immediate renal function (P less than 0.03) (group IV). A significant decrease in plasma Fn levels occurred immediately after steroid therapy was stopped (P less than 0.03) in patients treated for acute rejection. Plasma Fn levels were significantly decreased in the presence of delayed graft function but did not predict rejection.
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PMID:Plasma fibronectin levels during acute rejection and acute tubular necrosis in renal transplant patients. 141 24

Human neutrophils adherent to a polystyrene plastic surface are vigorously activated, whereas those adherent to fibronectin manifest only a priming response. The basis of these metabolic differences was further characterized; polystyrene-adherent cells, which were shown to spread quickly upon adhesion, exhibited an increase of cytoskeleton-associated actin (F-actin) (measured by a nitrobenzoxadiazole-phallacidin fluorescent staining assay) and a decrease of monomeric G-actin concentration (measured by a DNase inhibition assay); in contrast, fibronectin-adherent cells exhibited little spreading and decreased their F-actin, after 1.5 min of adhesion, to 33.49 +/- 6.9% (mean +/- SD, n = 5) of initial levels found in suspended cells before plating. Actin depolymerization in fibronectin-adherent cells was confirmed by measuring G-actin, which sharply increased during the first minute of adhesion, rising from 0.065 +/- 0.007 to 0.20 +/- 0.035 microgram/microgram of protein (mean +/- SEM, p less than 0.05), and then remained elevated during 5 min of observation. In contrast, soluble fibronectin induced a decrease of G-actin in suspended cells. Cells pretreated with 1 microM cytochalasin D and allowed to adhere to a plastic surface did not spread, failed to generate O2-, and exhibited elevated concentrations of G-actin (0.1 to 0.2 microgram/microgram of protein) during the 5 min of observation. Actin changes, as well as respiratory burst, in adherent cells were shown to proceed through a pertussis toxin-insensitive pathway. Fluo-3 measurements of intracellular Ca2+ concentrations ([Ca2+]i) showed a fourfold and twofold [Ca2+]i increase in polystyrene- and fibronectin-adherent cells, respectively, after 2 min. The small rise in [Ca2+]i in fibronectin-adherent cells corresponds to a primed response of these cells to subsequent activation with FMLP. Ionomycin (1 microM) added to neutrophils just before adhesion on fibronectin induced full activation, i.e., O2- production and actin polymerization. The metabolic events controlling metabolic priming and actin depolymerization are as yet uncharacterized, but fibronectin receptor-linked responses beyond the mediation of cell adhesion have now been identified, suggesting complex metabolic functions of integrin receptors.
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PMID:Comparison of actin changes and calcium metabolism in plastic- and fibronectin-adherent human neutrophils. 150 Jul 23

Studies with a range of monoclonal and polyclonal antisera to components of the human, rat, and chick vitronectin receptor, alpha V beta 3, and the VLA beta 1 chain show that chick and rat osteoclasts express similar integrin receptors to those described in man. Biochemical analysis with monoclonal antibody 23C6 confirmed the presence on chick osteoclasts of a vitronectin receptor heterodimer of similar size (110/95 kDa reduced) to that immunoprecipitated from human osteoclastoma giant cells. The synthetic peptide GRGDSP, corresponding to the cell adhesion sequence in fibronectin, but not GRGESP peptide, induced significant (P less than 0.005) osteoclast retraction in chick and rat osteoclasts at IC50s (+/- SEM) of 210.0 +/- 14.4 and 191.4 +/- 13.7 microM, respectively; monoclonal anti-vitronectin receptor alpha V beta 3 complex antibody, 23C6, produced similar changes in chick osteoclasts (IC50 = 1.45 +/- 0.22 microM). Antibody 23C6 inhibited the number of pits resorbed in dentine by chick osteoclasts over a concentration range of 4.4 to 88 micrograms/ml; a significant 76% reduction (P = 0.03) was observed at a final concentration of 88 micrograms/ml (6 microM). The effect of peptides upon dentine resorption was less dramatic. No consistent inhibition was seen using chick osteoclasts. Inhibitory effects on resorption by rat osteoclasts were, however, observed; significant reduction in resorption occurred with both GRGDSP (78%; P less than 0.01) and GRGESP (67%; P = 0.02) peptides at 400 microM peptide concentration. These data demonstrate that osteoclast function can be disrupted by low concentrations of the anti-vitronectin receptor antibody, 23C6. The inhibitory effects of the peptides used in this study produced effects on dentine resorption which were generally weaker and variable, although osteoclast cell adhesion was consistently inhibited in an Arg-Gly-Asp (RGD)-dependent manner. We conclude that the vitronectin receptor may play an important role in effecting resorption of mineralized tissues by osteoclasts.
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PMID:Arg-Gly-Asp (RGD) peptides and the anti-vitronectin receptor antibody 23C6 inhibit dentine resorption and cell spreading by osteoclasts. 171 31

It has been suggested that matrix molecules like fibronectin and laminin influence the differentiation and migration of embryonic cells. We investigated the role of these two glycoproteins in somitogenesis as well as in the differentiation and migration of the avian Wolffian (pronephric and mesonephric) duct. At first, we described essential steps in the development of these two organ anlagen by light microscopy, SEM and TEM. To localize fibronectin and laminin more exactly in the actual stages, we used the indirect immunoperoxidase reaction at the light microscopic level and the peroxidase-antiperoxidase technique at the ultrastructural level. Fibronectin was found at the surface of the unsegmented paraxial mesoderm, increasing in the cranial direction, and in the basal laminae of somites and Wolffian duct. The mesenchymal tip of the duct contains a moderate amount of fibronectin. In the two investigated organ anlagen, laminin was found mainly in the basal laminae. The role of fibronectin and laminin was investigated further by using synthetic peptides that mimic the main cell binding domain of either fibronectin or laminin, and that competitively inhibit their cell surface receptors. Thus, the pentapeptides GRGDS, YIGSR, and for control, SHLVE were micro-injected under the ectoderm of 2-day-old embryos. After treatment with GRDS, the Wolffian duct and the segmental plate are more compact. The rounded cells exhibit only short processes and narrow intercellular spaces. At the side of injection the duct shows a delay in migration. After treatment with YIGSR the Wolffian duct migrated laterally over the somatopleure. The basal laminae seem to be incomplete. SHLVE had no effect. Our results suggest that fibronectin is a prerequisite for the migration of the Wolffian duct, and that laminin probably plays a role in guiding the duct. The epithelialization during somitogenesis and differentiation of the duct is a more complex process involving also fibronectin and laminin.
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PMID:The role of fibronectin and laminin in development and migration of the avian Wolffian duct with reference to somitogenesis. 186 90

Growth factor-induced changes of cytosolic free calcium ion concentration ([Ca2+]i) and phosphatidylinositol (PI) turnover in cultured human retinal pigment epithelial (RPE) cells were studied, and their temporal relationship was compared. After a 24-hr serum depletion, RPE cells were loaded with fura-2/AM, and [Ca2+]i was analyzed using a digital imaging microscopy system. The resting [Ca2+]i in a single cultured human RPE cell was 153 +/- 1.5 nM (mean +/- the standard error of the mean [SEM], n = 105). The percentage of reactive cells that had Ca2+ transients induced by various growth factors were: epidermal growth factor, 18%; basic fibroblast growth factor (bFGF), 5%; nerve growth factor, 15%; platelet-derived growth factor (PDGF), 70%; insulin-like growth factor, 0%; fibronectin, 0%; insulin, 3%; and fetal bovine serum (FBS), 100%. The PDGF showed a peak concentration of 237 +/- 4.7 nM (mean +/- SEM, n = 67) and FBS, 774 +/- 34.5 nM (mean +/- SEM, n = 52). Chelation of the extracellular Ca2+ by EGTA made the resting and peak concentration lower. The Ca2+ transients occurred within 60 sec and lasted less than 5 min after the application of the growth factors. However, measurements of phosphoinositides in 24-hr serum-starved RPE cells revealed that growth factor-induced PI turnover was much slower than Ca2+ transients. In addition, FBS, bFGF, and PDGF increased the contents of inositol phosphate, inositol biphosphate, and inositol triphosphate (IP3) in RPE cells slowly up to 60 min except that PDGF showed a peak of IP3 at 15 min after stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Growth factor-induced cytosolic calcium ion transients in cultured human retinal pigment epithelial cells. 191 91

Reduced oxygen tension is regarded as the primary physiologic signal for the production of erythropoietin (EPO). There is little information available about early changes of EPO production in man due to severe hypoxia. The purpose of the present study was to examine the time course of EPO in serum of patients with acute cardiogenic pulmonary edema (ACPE). In 29 patients (seventy-five +/- six years, mean age +/- SEM) who were hospitalized within two hours after onset of symptoms of ACPE, serum EPO concentrations were monitored for up to seventy-two hours. At the moment of admission all patients showed significantly increased EPO concentrations of 121 +/- 64 mU/mL (mean +/- SEM) compared with a healthy population (15-35 mU/mL). Twenty-three patients who recovered within thirty minutes (group A) exhibited a quick return of their EPO serum levels to normal. The remaining 6 patients (group B) had a protracted clinical course and their EPO concentration showed a further increase up to the end of the observation period. The comparative monitoring of concentrations of alpha-1-proteinase inhibitor, antithrombin III, C-reactive protein, fibronectin, hapotoglobin, and transerrin in serum and plasma revealed no significant changes. Thus a major contribution of fluid shifts into or from the intravascular compartment to the observed changes in EPO concentration seems to be unlikely. The data suggest that the production and release of EPO in the kidneys due to altered oxygen delivery is a fast-responding mechanism.
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PMID:Serum-erythropoietin concentration during acute cardiogenic pulmonary edema. 201 19

Severely malnourished young children (n = 72) were treated with intravenous fibronectin to assess its efficacy as an adjunct treatment for kwashiorkor and/or marasmus. The protein was given in a double-blind study during the first 4 d of hospitalization together with standard nutrition and supportive therapy. Fibronectin concentrations as well as albumin, transferrin, prealbumin, and alpha-2-macroglobulin were monitored in samples taken before each dose of fibronectin and in samples taken five times thereafter. Sick individuals had significantly lower concentrations of all five proteins than did healthy control individuals of matching ages. Mean fibronectin concentrations were 98 +/- 7 mg/L (mean +/- SEM) for sick vs 303 +/- 21 mg/L for healthy individuals. Concentrations of all five proteins increased at a greater daily rate in patients treated with fibronectin than in patients who received placebos. Eighty-seven percent of the treated children survived to the end of the treatment and observation periods (mean hospitalization 14.7 d) whereas only 56% of the control subjects survived (P = 0.004). These data support the use of intravenous fibronectin as an adjunct in the treatment of severe malnutrition at a dosage of 7.5 mg.kg-1.d-1 over a 4-d period.
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PMID:Improvement in plasma protein concentrations with fibronectin treatment in severe malnutrition. 211 55

The pharmacokinetics and thrombolytic properties of a variant of human tissue-type plasminogen activator (t-PA), obtained by deletion mutagenesis of the NH2-terminal fibronectin-like finger (F) and epidermal growth factor (E) domains, and substitution of the three known glycosylated Asn residues by Gln (t-PA-delta FE3X), were studied in dogs with a copper coil-induced thrombosis of the left anterior descending coronary artery. Bolus injections were given during 2 min to groups of three dogs. Injection of 0.15 mg/kg resulted in peak antigen levels in plasma of 1.58 +/- 0.72 micrograms/ml (mean +/- SEM) and caused reperfusion within 14 +/- 6 min. With 0.075 mg/kg, corresponding values of 0.81 +/- 0.20 micrograms/ml and 31 +/- 15 min were obtained. A bolus of 0.038 mg/kg yielded plasma peak levels of 0.43 +/- 0.20 micrograms/ml but did not cause coronary recanalization within 3 h. A bolus injection of natural t-PA (Mel-t-PA) at a dose of 0.1 mg/kg in four dogs resulted in plasma peak levels of 0.46 +/- 0.09 micrograms/ml and caused partial coronary artery reperfusion within 3 h in one of four dogs (after 31 min). None of these injections caused a significant decrease of the fibrinogen level. Pharmacokinetic parameters for t-PA-delta FE3X were alpha half-life (t1/2) 14-18 min, beta t1/2 72-125 min, and plasma clearance 21-36 ml/min. For Mel-t-PA, the corresponding values were 3 min, 8 min, and 520 ml/min. We conclude that the variant t-PA-delta FE3X has a markedly longer plasma t1/2 than does Mel-t-PA and, when administered as a bolus injection, a higher thrombolytic efficacy.
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PMID:Pharmacokinetics and thrombolytic properties of a nonglycosylated mutant of human tissue-type plasminogen activator, lacking the finger and growth factor domains, in dogs with copper coil-induced coronary artery thrombosis. 245 51

This study evaluates the potential for endothelial seeding of a collagen-impregnated Dacron graft with or without surface modifiers (fibronectin, heparin) to attach and retain these cells during flow. Human umbilical endothelial cells were harvested, cultured, labeled with Indium111-oxine and seeded onto 30 mm X 4 mm diameter grafts. Six graft surfaces were studied: 1) a collagen-impregnated Dacron graft, HemashieldR (C); 2) C + fibronectin (C + F); 3) C + heparin (C + H); 4) C + F + H; 5) HytrelR + F (Hyt + F); and 6) Hyt + F + H. Radioactive loss determined the percentage attachment and then percentage retention of labeled inoculum after a one-hour in vitro perfusion. Scanning electron and light microscopy demonstrated the endothelium on the graft surface following perfusion. Fibronectin-coated grafts had a significantly higher percentage attachment than those without fibronectin (ANOVA, P less than 0.05). However, the percentage retention following perfusion was similar for all Dacron grafts and statistically inferior to the HytrelR grafts studied (ANOVA, P less than 0.05). SEM evaluation of the C + F + H graft surface was qualitatively the most impressive Dacron surface for seeding, yet was inferior to the HytrelR graft. We conclude that fibronectin benefits the initial attachment of endothelium to collagen-coated Dacron rivaling the HytrelR surface. Fibronectin does not improve percentage retention of the HemashieldR surface during perfusion, therefore, some of its initial benefit is lost.
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PMID:An experimental collagen-impregnated Dacron graft: potential for endothelial seeding. 252 47


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