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

We have used fluorescein isosthiocyanate-conjugated gelatin (FITC-gelatin) (1 mg/ml) to localize cell surface fibronectin in unfixed live cells in cultures. FITC-gelatin stains the fibronectin matrix on primary cultures of rat and chick embryo fibroblasts as well as untransformed, established cell lines. In live cultured cells, fibronectin in many areas of the extracellular matrix is inaccessible to antibody and cannot be visualized by immunofluorescence staining. In contrast, fibronectin in these areas is fully stainable by FITC-gelatin. At a low concentration (20 micrograms/ml), FITC-gelatin stains the fibronectin matrix of primary cultured cells but not of "untransformed" established cell lines. SEM can detect only the matrix stainable with the low concentration of FITC-gelatin, such as that expressed by primary chick embryo fibroblasts. The binding of fibronectin to the extracellular matrix is very stable and FITC-gelatin remained bound to the matrix for at least 10 d in culture. Radioiodinated gelatin has been used to quantitate the level of cell surface fibronectin in living normal and transformed cells. FITC-gelatin appears to be a useful probe for studying the fibronectin of living cells in culture.
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PMID:Studies of fibronectin matrices in living cells with fluoresceinated gelatin. 699 87

The nephrotoxicity of cyclosporin A (CSA) after chronic treatment is well known and includes in later stages tubular atrophy associated with interstitial fibrosis. In order to examine whether interstitial fibrosis due to CSA treatment in vivo is related to a hyperproliferative activity of fibroblasts, the effects of CSA on the growth characteristics of cultured human skin fibroblasts (HUSF) were investigated at CSA concentrations ranging from 10 ng/ml to 50 micrograms/ml. We found that CSA at concentrations higher than 7.5 micrograms/ml inhibited cell proliferation (p < 0.05 at concentrations above 5 micrograms/ml; n = 3) and cloning efficiency (p < 0.05 at concentrations above 5 micrograms/ml; n = 3) in a dose-dependent manner and caused a promotion of cell attachment at concentrations above 10 micrograms/ml (p < 0.05; n = 4), but did not influence cell spreading. At lower concentrations CSA-treated HUSF did not differ in their growth characteristics from the corresponding controls. A 50% inhibition of proliferation was calculated by extrapolation for a CSA concentration of 70 micrograms/ml for HUSF. The inhibition of HUSF proliferation was reversible even at the highest CSA concentration of 50 micrograms/ml. Under the same experimental conditions, a 50% inhibition of proliferation was observed for Madin-Darby canine kidney (MDCK) cells to be 5.5 micrograms/ml, e.g. at a 15-fold lower CSA concentration. Moreover, CSA caused a dose-dependent and reversible cell elongation of HUSF and a significant increase in the average cell diameter from 19.2 +/- 0.3 microns (control; mean +/- SEM, n = 4) to 22.2 +/- 0.2 microns for 50 micrograms/ml CSA (mean +/- SEM, n = 4) and in median cell volume from 4,210 +/- 160 fl (control; mean +/- SEM, n = 4) to 7,020 +/- 190 fl for 50 micrograms/ml CSA (mean +/- SEM; n = 4). These alterations described above were not correlated with a cytotoxic effect as checked by a fluorescent staining for cell vitality. Alterations in the organization of cytoskeletal components such as stress fibers, intermediate-sized filaments and microtubules directly due to CSA treatment were not observed. In contrast, the amount of fibronectin present on the cell surface was considerably increased by CSA. Although HUSF in culture do not respond to CSA treatment by an increased proliferative activity, they are much less affected by CSA than other cell types (i.e MDCK cells).(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Human fibroblasts in culture exhibit a low sensitivity against cyclosporin A treatment. 752 75

The nephric duct of the chick embryo starts to form at about stage 10 of Hamburger and Hamilton ([1951] J. Morphol. 88:49-92) and extends posteriorly, fusing with the cloaca at about the end of the third day of incubation (HH stage 17). Evidence from the literature suggests that the extension involves active migration of the posterior tip. This investigation concerned some molecules that might control this migration: fibronectin, vitronectin, the beta 1 integrin receptor, and NCAM polysialic acid. The concentration of fibronectin in the extracellular matrix was found by immunocytochemistry to be negligible at the posterior end of the duct; treatment of the living embryo with GRGDS failed to halt further extension of the duct; SEM examination of embryos treated with the synthetic peptides of fibronectin GRGDS, GRDGS, SDGR, and GRGES, or with vitronectin, revealed negligible morphological effects on the duct. It is concluded that there is yet no evidence that fibronectin is an important factor in duct migration. NCAM polysialic acid had a similar distribution to fibronectin, but treatment of the living embryo with Endo-N caused cessation of extension of the duct. Endo-N is an enzyme that specifically degrades PSA without affecting the NCAM polypeptide itself. It is suggested therefore that PSA may play an important role in duct extension. The synthetic peptides of fibronectin each produced distinctive patterns of blebbing on the surfaces of cells in trunk mesoderm, but the duct cells were unaffected. GRGES and SDGR caused blebbing on cells in the somites and the anterior segmental plate, though not on cells in the posterior segmental plate. This suggests that integrin receptors change in the anterior segmental plate as the mesoderm forms somites from somitomeres.
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PMID:Posterior extension of the chick nephric (Wolffian) duct: the role of fibronectin and NCAM polysialic acid. 754 37

Although increased plasma fibronectin (PF) levels have been found in diabetic patients with microalbuminuria, there is still controversy about its clinical implication for detecting early diabetic nephropathy. To evaluate the PF concentration as a possible marker for early diabetic nephropathy, three groups of sex-and age-matched patients were studied I) 22 insulin dependent diabetic (IDDM) patients with microalbuminuria (mean age +/- SEM: 23.3 +/- 3.6 years, mean urinary albumin excretion rate (AER) +/- SEM: 47.1 +/- 39.5 micrograms/min); II) 17 IDDM patients with normoalbuminuria (mean age: 23.4 +/- 4.4 years, mean AER: 7.8 +/- 2.1 micrograms/min) and III) 20 healthy control subjects (mean age: 22.6 +/- 4.1 years, mean AER: 6.7 +/- 2.1 micrograms/min). PF and urinary excretion of albumin were measured by an immunoturbidimetric method using commercially available kits (Boehringer Mannheim GMBH FRG, and Miles Lab., UK). The mean PF was significantly higher in the group with microalbuminuria (406.5 +/- 122.9 micrograms/ml) than in the group with normoalbuminuria (295.6 +/- 96.9 micrograms/ml, P < 0.01) or in the control group (299.54 +/- 105.5 micrograms/ml, P < 0.01). A weak positive correlation was found between PF and urinary albumin values (r = 0.35, P < 0.05). There were no significant correlations between PF and the other variables such as age, duration of diabetes, body mass index, arterial blood pressure, fasting blood glucose, fructosamine and HbA1 in the diabetic patients or in the control group. Our results suggest that the PF concentration could be a weak marker for early diabetic nephropathy. We cannot therefore use PF instead of microalbuminuria because there is only a weak correlation between PF and microalbuminuria.
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PMID:Can we use plasma fibronectin levels as a marker for early diabetic nephropathy. 762 76

Fibronectin like antigen (Fn) and transferrin (Trs) levels were measured in the seminal plasma of 40 fertile and 102 infertile men. The concentrations of both proteins were significantly (P < 0.001) higher in the fertile controls compared to the infertile groups. The levels of Fn and Trs (mean value +/- SEM) in the fertile men were 857.9 +/- 9.8 micrograms ml-1 and 164.0 +/- 6.5 micrograms ml-1, respectively; in the azoospermic men (n = 17) 552.7 +/- 24.65 micrograms ml-1 and 20.7 +/- 2.19 micrograms ml-1, respectively; in the group of severe oligozoospermia (n = 35) 568.34 +/- 25.7 micrograms ml-1 and 31.1 +/- 4.18 micrograms ml-1, respectively; in the moderate oligozoospermic group (n = 8) 572.50 +/- 47.9 micrograms ml-1 and 43.4 +/- 15.4 micrograms ml-1 respectively, and in the asthenozoospermic group (n = 26) 512.76 +/- 40.4 micrograms ml-1 and 47.0 +/- 7.9 micrograms ml-1, respectively. Of special interest was the finding from a group of 16 normospermic men (partners of couples with unexplained infertility) who showed significantly lower levels of Fn like antigen, 632.5 +/- 26.9 micrograms ml-1 (P < 0.001) and Trs 41.8 +/- 6.94 micrograms ml-1 (P < 0.0001) compared to normals. No correlation was found between Fn levels with either Trs or FSH levels or sperm count. In conclusion, our results indicate that male infertility is associated with changes in seminal plasma Fn like antigen concentrations and that it can be possibly used as an index of sperm fertilizing capacity.
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PMID:Seminal fibronectin-like antigen and transferrin concentrations in infertile and fertile men. 763 43

We examined DNA synthesis in non-enzymatically isolated neonatal rat pancreatic islets sub-cultured to eliminate fibroblast contamination, which was excluded both by demonstrating no effect of fibroblast growth factor (FGF) on 3H-thymidine incorporation and by immunofluorescence of attached islets using a mouse anti-fibroblast monoclonal antibody. 3H-thymidine incorporation in islets increased with increasing glucose up to a concentration of 21.1 mM in both free-floating islets (11,789 cpm/micrograms DNA +/- 1,610 SEM) and islets attached to fibronectin coated plastic (43,043 cpm/micrograms DNA +/- 9,203 SEM). These values were significantly higher when compared to 3H-thymidine incorporation in medium containing 11.1 mM glucose (p < 0.007, and p < 0.0001 for free-floating and attached islets respectively). 3H-thymidine incorporation was significantly higher in attached islets than in free-floating islets at all glucose concentrations tested (p < 0.005 at 11.1 mM, 16.1 mM, and 21.1 mM; and p < 0.01 at 26.1 mM). 5-bromo-2'-deoxyuridine (BrDU) staining of islets showed an increased number of positive nuclei in cells localised within attached islets (37.6 nuclei per islet +/- 5.1 SEM) compared to free-floating islets (7.62 nuclei per islet +/- 1.04 SEM, p < 0.001), indicating that attachment influenced proliferation of islet cells not physically in contact with the matrix. No difference in glucose-stimulated insulin release was observed between attached and free-floating islets. In conclusion, a fibroblast free islet culture was used to document the stimulatory effect of islet attachment on DNA synthesis, which was greater than the stimulation exerted by glucose alone.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:In vitro growth of neonatal rat islet cells is stimulated by adhesion to matrix. 764 70

Hypersensitivity pneumonitis (HP) is characterized by the accumulation of inflammatory cells in the lung parenchyma, and may progress to fibrosis. The content of the fibroblast derived collagen metabolite procollagen-III-peptide (PCP-III) in bronchoalveolar lavage (BAL) fluid of HP patients has been found to be increased. Previous studies have shown elevation of the fibroblast adhesion molecules, vitronectin and fibronectin in the BAL fluid of recent onset HP. In view of these observations, it was hypothesized that increases in PCP-III would be associated with increases in vitronectin and fibronectin in the BAL fluid of subjects with untreated recent onset HP. BAL was performed in 14 patients with HP and nine normal controls. The aminoterminal domain of PCP-III was measured by radioimmunoassay, and vitronectin and fibronectin by enzyme-linked immunosorbent assay. Detectable amounts of BAL PCP-III were seen in all HP patients but not in the normal controls (mean +/- SEM 5.1 +/- 1.2 versus < 0.2 ng.ml-1; i.e. below the limit of detection of the PCP-III assay). The BAL fluid concentration of PCP-III correlated well with the amount of vitronectin (r = 0.638) and fibronectin (r = 0.710). Except for PCP-III and mast cells, no significant correlations were found between PCP-III, vitronectin, fibronectin and the cellular parameters. The findings suggest that an increased turnover of collagens and proteoglycans is present in the lower respiratory tract of patients with recent onset HP, possibly reflecting remodelling of the extracellular matrix.
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PMID:Bronchoalveolar lavage procollagen-III-peptide in recent onset hypersensitivity pneumonitis: correlation with extracellular matrix components. 768 10

Bronchoalveolar lavage (BAL) has gained widespread use as a tool for investigating human lung diseases. In certain cases, it can be useful to obtain BAL material in a serial manner. There is convincing evidence from experimental and clinical studies that BAL can cause influx of neutrophils into the bronchoalveolar space. However, conflicting data have been reported on whether this side effect of BAL also affects previously nonlavaged lung areas. In addition, there is little information available on whether multiple repetitive BAL procedures cause damage to lung tissue. To reexamine the short-term effects of serial BAL procedures, the left lung of 10 cynomolgus monkeys was lavaged with five 20-ml aliquots of saline four times at 24-h intervals (Group A). 72 h after the initial BAL, the right lung was lavaged as a control. The percentage of neutrophils increased significantly (p < 0.05), with the greatest effect seen at 48 h (30.7 +/- 5.8 versus 0.8 +/- 0.3%, mean +/- SEM). No significant changes were observed in the control BAL of the right lung at 72 h. A multidisciplinary approach was used to assess the long-term effects of multiple BAL procedures. BAL was performed 14 times over 26 mo at 2-mo intervals (Group B, n = 5). The right lung was lavaged as a control 25 mo after the initial BAL. In addition to standard cellular BAL parameters, the concentrations of fibronectin, procollagen III amino-terminal peptide-related antigen, total phospholipids, and lactate dehydrogenase activity were measured.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Short-term and long-term effects of serial bronchoalveolar lavages in a nonhuman primate model. 802 42

Human neutrophils (5 x 10(4) incubated on fibronectin precoated wells released 2.83 +/- .25 nmoles of superoxide (0(2)-) (x +/- 1 SEM, n = 15) in response to 5.9 nM (100 ng/ml) Tumor Necrosis Factor Alpha (TNF). On the contrary, the 0(2)- production induced by interleukin-8 (IL-8) (doses ranging from 0.1 nM to 1 microM) was comparable to that of "resting" cells (< .6 nmoles/5 x 10(4) cells). IL-8 (100 nM) did not affect the TNF-dependent 0(2)- production when added with TNF at the beginning of the assay, but reduced it by approximately 80% when added with TNF on neutrophils previously incubated for 1 hour on fibronectin. As compared with IL-8, N-formyl-methionyl-leucyl-phenylalanine (FMLP, 100 nM) failed to suppress the TNF-triggering of the oxidative burst in neutrophils plated on fibronectin. The data suggest that the interaction of neutrophils with fibronectin uncovers the capacity of IL-8 to limit the cell response to TNF, without affecting the response to the combination of FMLP and TNF. Thus, although the chemotactic factors IL-8 and FMLP share the capacity of triggering the oxidative burst of neutrophils incubated in suspension, only IL-8 has the potential to down-regulate the responsiveness of fibronectin-adherent cells to TNF.
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PMID:Interleukin-8 down-regulates the oxidative burst induced by tumor necrosis factor alpha in neutrophils adherent to fibronectin. 804 57

Gestational proteinuric hypertension (GPH), a major cause of maternal death, may be characterised by hypertension and proteinuria alone or may progress to disturbed coagulation and multiorgan failure. Since the condition can only be reversed by termination of pregnancy, there is a need for reliable indicators of severity. We found circulating levels of tissue plasminogen activator (tPA) (27.98 +/- 2.12 v. 7.17 +/- 0.81 ng/ml, mean +/- SEM), fibrin(ogen) degradation products (FDP) (7.55 +/- 1.99 v. 1.92 +/- 0.47 micrograms/ml) and fibronectin (221 +/- 15.2 v. 120 +/- 15.2 micrograms/ml) to be significantly increased in 21 patients with severe GPH when compared with 21 normotensive, age- and gestational age-matched pregnant controls. More importantly, patients who developed severe GPH showed a progressive increase in tPA and FDP levels with time. This was in contrast to patients who had hypertension and proteinuria alone, in whom tPA and FDP concentrations did not increase. Parallel measurements did not reveal a fall in platelet count or an increase in urinary protein excretion in patients who subsequently progressed to severe disease. Our findings may be of assistance to clinicians faced with the need to prolong pregnancy in patients with GPH in order to ensure fetal viability.
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PMID:Serial measurements of circulating tissue plasminogen activator and fibrin(ogen) degradation products predict outcome in gestational proteinuric hypertension. 811 15


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