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C Rüegg

Publications and source records attributed to C Rüegg.

33 records · Page 2Linked to original sources
PubMed1997

Systemic release of soluble TNF receptors after high-dose TNF in isolated limb perfusion.

Isolated limb perfusion (ILP) with high dose tumour necrosis factor (TNF), interferon gamma and melphalan (TIM) is an efficient treatment for patients with regionally advanced melanoma and sarcoma. In 44 patients, we determined the kinetics of soluble TNF receptors (sTNF-RI and RII) plasma concentrations, and correlated them with systemic TNF and interleukin 6 (IL-6) levels and shock. Seven patients treated conventionally by ILP without cytokine served as controls. Elevated levels of both sTNF-Rs were observed within 30 min after beginning of the TIM-ILP. A first peak of sTNF-Rs levels was observed 3 h after ILP and was followed by a rapid decrease reaching a nadir at 12-14 h post ILP. This first peak was followed by a second, long-lasting elevation of both sTNF-Rs levels persisting for 4 to 5 days after TIM-ILP. Patients treated by ILP without TNF/interferon gamma (IFN-gamma) had no detectable increase in either sTNF-Rs or in circulating TNF, demonstrating that the release of TNF-Rs was dependent upon the administration of TNF/IFN-gamma. High plasma levels of TNF and IL-6 were observed in patients that had more than 5% leakage during the TIM-ILP, but no significant correlation between TNF levels and the peak values of both sTNF-Rs was observed. The levels of TNF and IL-6 were, however, significantly related to each other. TNF systemic levels, but not sTNF-Rs concentrations, correlated significantly with the severity of the shock observed after TIM-ILP. Patients in which sTNF-RII concentration was in excess over circulating TNF, had no shock or grade I shock only, suggesting that sTNF-RII may play a protective, although limited, role in inhibiting activity of circulating TNF.

Chemotherapy, Cancer, Regional Perfusion↗
PubMed1997

Role of integrins and evidence for two distinct mechanisms mediating human colorectal carcinoma cell interaction with peritoneal mesothelial cells and extracellular matrix.

Peritoneal carcinomatosis involves a series of events including tumor cell interactions with mesothelial cells and the extracellular matrix (ECM). We have studied the adhesive and invasive properties of four human colorectal carcinoma cell lines (Co115, HT29, SW480, SW620) confronted in vitro with a human mesothelial cell monolayer or with the ECM proteins collagen IV, laminin-1, fibronectin, tenascin-C and vitronectin. Quantitation was achieved following staining of tumor cells with the calcein-AM fluorescent dye. We found that all four cell lines rapidly adhered to a mesothelial cell monolayer. This adhesion event was not inhibitable by anti-integrin and anti-CD44 antibodies. Following initial attachment, the SW480 and SW620 cells invaded the mesothelial cell monolayer more aggressively than HT29 and Co115 cells. All cell lines adhered to ECM proteins with each one exhibiting an individual adhesion pattern. Adhesion to matrix was completely integrin-dependent. When tested in an invasion assay, HT29 and Co115 cells crossed Matrigel-coated filters while SW480 and SW620 cells did not. This invasion was inhibited by anti-beta 1 integrin antibodies. Taken together, our results demonstrate that the initial colorectal tumor cell-mesothelial cell interaction occurs through an integrin-independent mechanism while adhesion to matrix proteins and invasion through Matrigel are integrin-dependent events. Furthermore, the different invasive capacity of SW480 and SW620 versus HT29 and Co115 cells upon interaction with a mesothelial cell monolayer or Matrigel suggests that these two invasion events may be mediated by distinct mechanisms.

Cell Adhesion↗
PubMed1997

Lack of antitumour activity of human recombinant tumour necrosis factor-alpha, alone or in combination with melphalan in a nude mouse human melanoma xenograft system.

The most promising developments in the field of isolated limb perfusion have centred around the use of the recombinant cytokine tumour necrosis factor-alpha (rTNF-alpha) in combination with melphalan. While the results of clinical trials are impressive, the exact antitumour mechanisms of rTNF-alpha and its role in combination with melphalan remain unclear. Our aim was to study the antitumour activity of human rTNF-alpha with or without the combination of melphalan in a nude mouse human melanoma xenograft system. In a first attempt to define the maximal tolerated single dose of rTNF-alpha in this setting, 15 animals were exposed to increasing doses of rTNF-alpha (60-2500 microg/kg intraperitoneally). All but one animal survived and tumour growth was not influenced by these single dose applications of rTNF-alpha even at the very high doses. Anti-tumour activity of repeated application of melphalan (three times 9 mg/kg in group 2 and three times 6 mg/kg in group 3), of rTNF-alpha alone (nine doses of 50 microg/kg in group 4), and of rTNF-alpha in combination with melphalan (nine doses of 50 microg/kg rTNF-alpha and three times 6 mg/kg melphalan in group 5) was further compared with non-treated animals (group 1). Tumour growth was significantly inhibited in all animals treated with melphalan (group 2, 3 and 5), but was not decreased in animals treated with rTNF-alpha alone (group 4). Mean final tumour volumes and mean tumour weight were not different in group 2 (789 +/- 836 mm3, 0.38 +/- 0.20 g), group 3 (1173 +/- 591 mm3, 0.55 +/- 0.29 g) and group 5 (230 +/- 632 mm3, 0.37 +/- 0.29 g), but significant lower than group 1 (3156 +/- 1512 mm3, 2.35 +/- 0.90 g) and group 4 (3228 +/- 1990 mm3, 2.00 +/- 1.16 g). There were no significant differences between high and low dose melphalan treatment and between melphalan treatment in combination with rTNF-alpha. Histological examination did not show differences between treated and non-treated animals besides slightly inhibited mitotic activities of tumour cells in melphalan-treated animals. While tumour growth of human xenotransplanted melanoma in nude mice could be inhibited by melphalan, we failed to demonstrate any antitumour effect of rTNF-alpha. The combination of melphalan and rTNF-alpha did not enhance the antiproliferative effect of melphalan alone. Human xenotransplanted tumours on nude mice might not be the ideal experimental setting for studies of potential direct antineoplastic activity of rTNF-alpha, and these results support the concept that TNF-alpha exerts its antitumour activity indirectly, possibly by impairing the tumour vasculature and by activating the immune system.

Animals↗
PubMed1995

Rapid increase in plasma tenascin-C concentration after isolated limb perfusion with high-dose tumor necrosis factor (TNF), interferon gamma (IFN gamma) and melphalan for regionally advanced tumors.

The matrix protein tenascin-C (TN-C) is present in the blood of healthy individuals at concentrations around 1 mg/l. Elevated serum levels have been reported in cancer patients. In this study we have measured the concentration of circulating TN-C in 40 patients with melanoma, soft-tissue sarcoma (STS) or squamous-cell carcinoma (SCC) of the limbs, and have found a minor increase in the mean concentration compared with healthy subjects. Only 10 patients had TN-C levels above the normal range. No correlation was observed between TN-C levels and tumor burden. Nineteen patients were treated by isolation limb perfusion (ILP) with TNF, IFN gamma, melphalan (11 melanoma, 2 SCC and I STS), melphalan alone (3 melanoma) or hyperthermia at 41.5 degrees C (2 melanoma). ILP with TNF, IFN gamma and melphalan induced a rapid increase in plasma TN-C levels, peaking in most patients between 24 or 48 hr after ILP. Two patients treated with hyperthermia only had a slow increase in TN-C concentration peaking at day 4, while the patients treated with melphalan alone had no significant change. In some cases elevated TN-C levels persisted for over 8 weeks after ILP. The early rise in TN-C concentration correlates with the increase in circulating C-reactive protein. Our findings suggest that circulating TN-C behaves, at least in part, as an acute-phase protein and that it may play a role in the inflammatory response.

Adult↗
PubMed1995

Sequence of a human transcript expressed in T-lymphocytes and encoding a fibrinogen-like protein.

A murine cDNA sequence (termed pT49), encoding a protein related to the fibrinogen (Fib) beta and gamma chains, has been previously reported [Koyama et al., Proc. Natl. Acad. Sci. USA 84 (1987) 1609-1613]. We used a murine pT49 probe to screen a human small intestine cDNA library, and obtained a set of overlapping cDNA clones encoding a Fib-like protein that is 80% identical with the product of the murine pT49 gene. The deduced amino acid (aa) sequence contains a predicted signal peptide and five consensus motifs for N-linked glycosylation. The presence of conserved Cys residues involved in the assembly of the mature Fib complex and of two alpha-helical regions permissive for coiled-coil formation, suggests that this Fib-like protein may be secreted as a multichain complex. Two mRNA species of approx. 4.5 and approx. 1.5 kb were detected by Northern blot hybridization of a human pT49-homolog cDNA probe with RNA obtained from resting peripheral blood T-lymphocytes. By RT-PCR analysis of purified peripheral blood T-lymphocyte subsets, we found expression of the pT49-homolog transcript in both CD3+/CD4+ and CD3+/CD8+ T-lymphocytes. The coding region of the human pT49-homolog cDNA was fused at its 3' end with a tag-coding sequence and was expressed in CHO cells. The corresponding gene product was immunoprecipitated with an anti-tag antibody from the cell lysate and from the culture supernatant of metabolically labeled transfectants and was identified as approx. 62 and approx. 64-70-kDa proteins, respectively.

Amino Acid Sequence↗
PubMed1994

[Hematological reference values for foals in the first two months of life].

Hematologic reference values were established in 18 healthy foals in the first two months of life. Blood samples were collected prior to colostrum consumption and at 30 hours, 1 week, 3, 5, 7 and 9 weeks of age. PCV, Hb and RBC decreased during the first week and RBC, but not PCV and Hb, increased toward the end of the second month. With the exception of the sample at 1 week, the foals had mean RBC values significantly higher than those of controls. Mean MCV and MCH did not change during the first week, but decreased slightly thereafter; all means were smaller than in controls. The numbers of neutrophils increased mainly during the first week, and the numbers of lymphocytes increased gradually during the first two months. The mean N:L-ratio was highest at 1 week and lowest at 5 weeks.

Animals↗
PubMed1993

Sequence and tissue distribution of the integrin alpha 9 subunit, a novel partner of beta 1 that is widely distributed in epithelia and muscle.

The integrin family of adhesion receptors consists of several heterodimeric glycoproteins, each composed of one alpha and one beta subunit. A novel integrin alpha subunit partial cDNA isolated from TGF-beta stimulated guinea pig airway epithelial cells has previously been reported (Erle, D.J., D. Sheppard, J. Bruess, C. Rüegg, and R. Pytela. 1991. Am. J. Respir. Cell Mol. Biol. 5:170-177). We have now determined cDNA and amino acid sequence for the human homolog of this subunit, named alpha 9, from a human lung cDNA library, a human small intestine cDNA library, and cDNA from the cell lines U937, HL-60 and Tera-2. This sequence is predicted to encode a 1006-amino acid mature protein that shares 39% identity with the previously identified integrin subunit alpha 4. By Northern blot analysis, alpha 9 mRNA was detected in the human carcinoma cell lines Tera-2 and Caco-2. Anti-peptide antibodies against the predicted COOH-terminal sequence of alpha 9 immunoprecipitated a heterodimer (140 kD/115 kD nonreduced; 150 kD/130 kD reduced) from Tera-2 lysates. Immunodepletion of beta 1-containing integrins with Tera-2 lysates removed alpha 9 immunoreactivity, suggesting that beta 1 is the principal beta subunit partner for alpha 9 in these cells. alpha 9 was detected by immunohistochemistry in airway epithelium, in the basal layer of squamous epithelium, and in smooth muscle, skeletal muscle, and hepatocytes.

Amino Acid Sequence↗
PubMed1992

Role of integrin alpha 4 beta 7/alpha 4 beta P in lymphocyte adherence to fibronectin and VCAM-1 and in homotypic cell clustering.

Integrins are heterodimeric cell surface proteins that mediate both cell-cell and cell-extracellular matrix interactions. We and others recently identified cDNAs encoding a novel integrin beta subunit, beta 7, in lymphocytes. We have now detected beta 7 mRNA in mouse TK-1 T lymphoma cells, which are known to express the putative Peyer's patch homing receptor alpha 4 beta P. We used an anti-peptide antiserum and a novel mAb against the beta 7 subunit to show that TK-1 cells express beta 7 as the only subunit associated with alpha 4. We conclude that beta 7 and beta P are identical. We also show that activated peripheral blood T cells express alpha 4 beta 7. We studied the function of alpha 4 beta 7/alpha 4 beta P in TK-1 cells, which do not express very late antigen (VLA)-4 (alpha 4 beta 1). Cells adhered to intact fibronectin and to a fibronectin fragment containing the CS-1 region, but not to a fragment containing the RGD sequence. Adhesion to fibronectin was inhibited by antibodies to alpha 4, suggesting that alpha 4 beta 7 is a fibronectin receptor. We confirmed that alpha 4 beta 7 binds to the CS-1 region of fibronectin using affinity chromatography. TK-1 cell adhesion to the vascular cell adhesion molecule VCAM-1 was also inhibited by antibodies to alpha 4, implying that alpha 4 beta 7 also plays a role in the adherence of lymphocytes to endothelial cells. TK-1 cell binding to fibronectin and VCAM-1 is markedly increased by brief PMA stimulation. We also found that mAbs against alpha 4 and beta 7 induce homotypic clustering of TK-1 cells. Taken together these results suggest that alpha 4 beta 7/alpha 4 beta P recognizes some or all of the same widely distributed ligands recognized by VLA-4 (alpha 4 beta 1) and that the role of alpha 4 beta 7/alpha 4 beta P may not be restricted to lymphocyte homing.

Amino Acid Sequence↗
PubMed1992

Evidence of a role for mesothelial cell-derived interleukin 8 in the pathogenesis of asbestos-induced pleurisy in rabbits.

Although acute asbestos-induced pleurisy is characterized by an influx of neutrophils, the identity of the factors that attract these cells to the pleural space and the source of the factors are unknown. We found that instillation of crocidolite asbestos into the pleural space of rabbits led to the appearance in pleural liquid of chemotactic activity for neutrophils, and that this chemotactic activity was inhibited significantly by a neutralizing antibody to human interleukin 8 (IL-8). Cultured rabbit pleural mesothelial cells incubated with crocidolite asbestos also released chemotactic activity for neutrophils, which was inhibited significantly by the anti-IL-8 antibody. To determine whether rabbit pleural mesothelial cells synthesize IL-8, we generated a probe for rabbit IL-8 mRNA by amplifying cDNA prepared from stimulated pleural mesothelial cells using the polymerase chain reaction (PCR) and primers based on homologous sequences in human and sheep IL-8 cDNAs. Homology-based PCR yielded a single cDNA fragment with a nucleotide sequence 88% identical to that of a corresponding region of human IL-8 cDNA. With the radiolabeled PCR product as a probe, we demonstrated rapid induction of IL-8 mRNA expression in pleural mesothelial cells exposed to asbestos. As expected, tumor necrosis factor-alpha also led to the appearance of IL-8 in the rabbit pleural space and stimulated cultured pleural mesothelial cells to synthesize and release IL-8. We conclude that asbestos directly stimulates pleural mesothelial cells to synthesize IL-8 and that mesothelial cell-derived IL-8 may play an important role in mediating asbestos-induced pleural inflammation.

Animals↗
PubMed1991

Complete amino acid sequence of an integrin beta subunit (beta 7) identified in leukocytes.

The integrins are a large family of heterodimeric cell-surface glycoproteins that play key roles in the adherence of cells to other cells and to extracellular matrix proteins. We have previously reported the identification of a novel integrin beta subunit partial cDNA from leukocytes. We have now determined the complete sequence of this subunit, designated as beta 7, from overlapping clones obtained from a PEER T leukemia cell library and a peripheral T cell library. The beta 7 cDNA contains a single large open reading frame predicted to encode a 798-amino acid protein precursor (signal peptide plus mature protein). The beta 7 protein, like the other beta subunit proteins, is predicted to contain a large extracellular portion, a transmembrane domain, and a cytoplasmic tail. The deduced beta 7 amino acid sequence is 32-46% identical to the six previously sequenced human integrin beta subunits. beta 7 is most similar to the leukocyte integrin common beta subunit (beta 2, CD18). Analysis of variant beta 7 cDNA clones and reverse transcription-polymerase chain reaction products suggest that alternatively spliced beta 7 mRNAs can be generated by the removal of exons that encode most of the cysteine-rich region of the extracellular portion of beta 7. By Northern blot analysis, beta 7 mRNA was detected in T and B cell lines and in macrophage-like cell lines, but not in any of the nonleukocyte cell lines tested. Peripheral T cells and some lymphoma lines express little beta 7 mRNA before stimulation; but after stimulation with phorbol ester, beta 7 mRNA levels increased markedly. Integrin beta 7 is expected to play a role in adhesive interactions of leukocytes.

Amino Acid Sequence↗
PubMed1991

Novel integrin alpha and beta subunit cDNAs identified in airway epithelial cells and lung leukocytes using the polymerase chain reaction.

The integrins are a large group of cell surface glycoproteins that mediate cell-matrix and cell-cell adhesive interactions. Integrins play a role in normal lung development, in host defense against pulmonary infection, and in the pathogenesis of the adult respiratory distress syndrome. Integrins are heterodimers consisting of one alpha subunit and one beta subunit. We identified consensus sequences within integrin subunits and used oligonucleotide primers based on these sequences to amplify cDNA by the polymerase chain reaction (PCR). We previously reported the use of this homology PCR technique for the identification of one novel integrin beta subunit, beta 6, from guinea pig airway epithelial cells. Here we demonstrate that primers based on alpha subunit consensus sequences can also be used for homology PCR. We have used the alpha and beta subunit primers to amplify and clone a large variety of integrin partial cDNAs from several cell types and species. Comparison of the deduced amino acid sequences reveals a high degree of cross-species conservation (86 to 98% identity). One alpha subunit (identified in guinea pig airway epithelial cells) and one beta subunit (identified in rabbit leukocytes obtained by bronchoalveolar lavage and in human and mouse leukocyte cell lines) have novel sequences that are related to but clearly distinct from all previously reported integrin sequences (24 to 61% identity). These novel cDNAs are very likely to encode previously unsequenced integrin subunit proteins that are expressed in the lung. Homology PCR is a powerful technique for the identification of known and novel integrin alpha and beta subunit cDNAs in cells from the lung and other organs.

Amino Acid Sequence↗
PubMed1982

Comparison of amino acid sequence and thermostability of tyrosinase from three wild type strains of Neurospora crassa.

The thermostability of tyrosinase from three wild type strains of Neurospora crassa has been investigated. For this purpose a sequence comparison of two thermostable and one thermolabile tyrosinase isoenzyme was carried out. It revealed that at position 201 the thermostable enzyme forms share an aspartate residue in contrast to an asparagine residue in the thermolabile form. In addition, one of the thermostable isoenzymes displays five other substitutions. Since the relative stability of the thermostable forms as compared to the thermolabile one decreases with increasing ionic strength, the common aspartate residue is thought to bring about the additional stability of the thermostable isoenzymes by forming a salt bridge between aspartate 201 and a positively charged group of the protein. The strong pH-dependency of the thermostability with an apparent pKA of 6.6 indicates a histidinium side chain as the most likely ionic group to be involved in the salt bridge. This conjecture is also supported by measurements of the stability towards the chaotropic agent guanidinium chloride. The difference of the free energy change of denaturation delta GDH2O between the apoenzymes of a thermostable and a thermolabile isoenzyme was calculated as 2.5 kcal mol-1. Furthermore, it was shown that the copper ions of the native and the cobalt ions of Co(II)-substituted tyrosinase strongly enhance the stability of the protein as compared to its apoform.

Amino Acid Sequence↗
PubMed1981

Cobalt tyrosinase: replacement of the binuclear copper of Neurospora tyrosinase by cobalt.

The antiferromagnetically spin-coupled copper(II) pair in Neurospora tyrosinase was substituted by cobalt, yielding a stoichiometry of 2 mol of Co/mol of protein. The low magnitude of the high-spin Co(II) EPR signal indicates spin coupling of the two Co(II) ions similar to that observed in the native enzyme. The absorption spectrum with four transitions in the visible region of intermediate intensity (epsilon 607(670), epsilon 564(630), epsilon 526(465)), a shoulder at 635 nm, and the near-infrared bands at 1180 (epsilon 30) and 960 nm (epsilon 15) indicate tetrahedral coordination around the Co(II) center. The cobalt(II) tyrosinase is enzymatically inactive, and there is no evidence that it binds molecular oxygen. Upon addition of cyanide or the competitive tyrosinase inhibitors L-mimosine, benzoic acid, or benzhydroxamic acid te absorption spectrum changes in a characteristic manner. This optical perturbation shows that binding of these inhibitors (and presumably of the substrates) occurs at or near the metal site. One Co(II) ion can be removed preferentially by incubation with KCN at high pH, indicating the two ions not to be in an identical environment.

Catechol Oxidase↗