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Biomedical subjects

C J Wiedermann

Publications and source records attributed to C J Wiedermann.

At least 91 records · Page 5Linked to original sources
PubMed1996

Interaction of substance P with epidermal growth factor and fibroblast growth factor in cyclooxygenase-dependent proliferation of human skin fibroblasts.

Substance P (SP), fibroblast growth factor (FGF), and epidermal growth factor (EGF) are mitogens for fibroblasts. EGF acts as a progression factor, whereas FGF and SP have competence factor activity. The ability of eicosanoids to regulate proliferation of fibroblasts and the increased production of prostaglandins by fibroblasts in response to the growth factors, led us to investigate the involvement of cyclooxygenase-dependent arachidonic acid metabolites in the mitogenic response of serum-starved human skin fibroblasts to SP, FGF, and EGF. We tested the interaction of a submaximal concentration of SP(10(-9)M) with baFGF(40 micrograms/ml) and EGF(0.01 microgram/ml) both on fibroblast proliferation and release of arachidonic acid metabolites. A combination of SP and EGF synergistically stimulated fibroblast proliferation and prostaglandin E2 release, whereas addition of SP to FGF-containing cultures did not affect cell growth. Inhibition of cyclooxygenase by acetylsalicylic acid augmented the growth response of fibroblasts to all: SP, FGF, and EGF. In the presence of acetylsalicylic acid, SP combined with FGF enhanced fibroblasts proliferation, whereas a combination with EGF inhibited cellular growth with respect to growth induced by EGF alone. Thus, interactions of SP with FGF and EGF differently affected the mitogenic response depending on the formation of arachidonic acid metabolites. The findings indicate that eicosanoids may be important mediators of competence and progression factor activities that may determine the effects of substance P on fibroblast proliferation in a cytokine network.

Animals↗
PubMed1996

RANTES chemokine expression in diseased and normal human tissues.

RANTES is a member of a large family of cytokines, called chemokines, which are thought to play a regulatory role in inflammatory processes. We have made recombinant human RANTES protein which was used to generate a panel of anti-RANTES monoclonal antibodies. Following characterization, select anti-RANTES monoclonal antibodies were used for immunohistologic staining of a large panel of normal, diseased and fetal tissue sections. Diseased tissues included eleven lymphomas and eight renal tumors. Most tissues were also tested in parallel for RANTES mRNA by in situ hybridization using RANTES mRNA specific oligomeric probes. As expected, most normal adult tissues contain few, if any, RANTES positive cells. In contrast, RANTES expression dramatically increases in inflammatory sites. In addition, megakaryocytes, some tumours, and select fetal tissues express high levels of RANTES message and protein. These results indicate a wider expression of RANTES than previously appreciated and suggest multiple physiologic roles for this soluble factor.

Animals↗
PubMed1996

Use of fluorochromes in the determination of chemotaxis and haptotaxis of granulocytes by micropore filter assays.

Most conventional assays for the in vitro measurement of polymorphonuclear leukocyte (PMN) migration are modifications of the Boyden chamber technique, which requires quantification of migrated cells on micropore filters. This quantification is accompanied by several disadvantages, comprising errors in direct cell counting, low sensitivity of turbidimetric methods, the loss of marker enzymes by activation of PMNs, or the use of radioactive isotopes. We set up an improved fluorometric method to measure chemotactic and haptotactic migration of PMNs using polycarbonate filter-bearing Transwell culture plate inserts. This improved fluorometric method allows the evaluation of effects of fluorescent-dye labeling on chemotaxis and haptotaxis - defined as cell migration due to cell surface- or matrix-bound gradients of chemoattractants - by collecting data in an automated system. Results were compared with data obtained from direct microscopic cell counting in Transwell experiments as well as in conventional 48-multiwell Boyden chamber assays. Calcein-AM and BCECF-AM proved to be fluorochromes with minimal effect on both types of PMN migration. We conclude that the fluorochromes are powerful tools for the analysis of PMN migration and allow modifications of chemotaxis/haptotaxis assays for automated quantification.

Chemotaxis↗
PubMed1995

Different patterns of deactivation of chemotaxis and haptotaxis of human peripheral blood mononuclear leukocytes by soluble and surface-bound attractants.

Soluble mediators and inducible cell-surface and matrix-bound molecules coordinate the cascade of events giving rise to leukocyte emigration. Knowledge of the specific mechanisms underlying the attraction of cells into a local site, however, remains sketchy. In particular, it is unclear how chemoattractants cause rapidly moving immune cells to adhere to the blood vessel wall and to enter tissues. Here we show that the neuroendocrine human growth hormone, a chemoattractant for monocytes and lymphocytes in vitro, promotes haptotaxis, the migration of the cells induced by surface-bound gradients. Combination of soluble growth hormone with soluble attractants, RANTES or formyl peptide, deactivates the migratory responses, as do combinations of surface-bound growth hormone with surface-bound RANTES or formyl peptide. In contrast, exposure of mononuclear leukocytes to combinations of soluble chemotactic with surface-bound haptotactic gradients of attractants does not deactivate migration. The findings suggest that growth hormone may act as haptotactic agent, on the one hand, and that soluble attractants do not appear to affect haptotaxis when acting in concert with a surface-bound attractant, on the other. This observation may have implications for the differential regulation of leukocyte accumulation in the vessel wall at systemic and local sites.

Amino Acid Sequence↗
PubMed1994

Fibroblast growth-promoting activity in proliferative vitreoretinopathy: antagonism by acetylsalicylic acid.

Proliferative vitreoretinopathy is a severe reactive process which leads to the formation of cellular membranes on the surface of the retina and in the vitreous. We determined the fibroblast growth-promoting activity of intraocular fluid from patients suffering from proliferative vitreoretinopathy, retinal detachment or cataract and further evaluated the effect of acetylsalicylic acid on growth-stimulated fibroblasts. The results demonstrated a significant enhancement of growth-promoting activity of intraocular fluid in proliferative vitreoretinopathy as compared to that of control samples. We showed that the augmented growth-promoting activity of intraocular fluid in proliferative vitreoretinopathy was significantly antagonized by inhibition of cyclooxygenase with acetylsalicylic acid (ID50 approximately 5 microM). In contrast, no significant effect was seen in corresponding control experiments. The findings suggest that metabolites of the cyclooxygenase pathway are involved in the regulation of enhanced intraocular fluid-induced fibroblast proliferation in proliferative vitreoretinopathy and that acetylsalicylic acid might be useful as an antiproliferative agent in intraocular fibrogenesis.

Adult↗
PubMed1994

Interleukin-1 receptor type I mRNA in mouse brain as affected by peripheral administration of bacterial lipopolysaccharide.

Following administration of endotoxin in vivo, alterations of interleukin-1 (IL-1) receptor binding have been reported. In order to assess in vivo regulation of IL-1 receptor gene expression in brain, mRNA levels for IL-1 receptor type I were measured after peripheral administration of bacterial lipopolysaccharide in mice. When 25 micrograms of lipopolysaccharide were administered intraperitoneally, IL-1 receptor type I mRNA in the brain was increased after 3 h. After 20 h, the level was diminished. This result suggests that bacterial lipopolysaccharide affects regulation of IL-1 receptor type I mRNA expression in mouse brain.

Animals↗
PubMed1994

Decreased beta-endorphin content in peripheral blood mononuclear leukocytes from patients with Crohn's disease.

Increased activation of lymphocytes in inflammatory bowel disease is reflected by alterations of various immunological functions including enhanced spontaneous secretion of rheumatoid factor by mononuclear cells. since in rheumatic diseases increased secretion of rheumatoid factor is associated with decreased levels of beta-endorphin in circulating blood mononuclear leukocytes, we investigated levels of leukocyte beta-endorphin in inflammatory bowel disease and compared them with those in hepatobiliary disorders and in healthy subjects. Levels of beta-endorphin were measured in extracts from peripheral blood mononuclear leukocytes by radioimmunoassay. beta-Endorphin levels ranged from 0 to 67 pg/10(6) cells. Mononuclear leukocytes from ulcerative colitis patients contained as much beta-endorphin as those from healthy control subjects. In patients with Crohn's disease, levels of beta-endorphin were reduced by as much as roughly 50%. An inverse relationship was found between leukocyte beta-endorphin on the one hand and erythrocyte sedimentation rate, blood granulocyte or thrombocyte counts, and C-reactive protein levels in plasma on the other. In patients with various hepatobiliary disorders including fatty liver disease, viral hepatitis, primary biliary cirrhosis, and cryptogenic or alcoholic cirrhosis, beta-endorphin levels were not significantly different from the normal range values. Data indicate that leukocyte beta-endorphin may be involved in regulation of the systemic inflammatory activity of Crohn's disease.

Adult↗
PubMed1994

Migration of neutrophils across endothelial monolayers is stimulated by treatment of the monolayers with beta-endorphin.

To study the effects of the cytokine and neuroendocrine hormone beta-endorphin on the transendothelial migration of neutrophils, bovine pulmonary artery endothelial cells were grown to confluence on PVP-free polycarbonate filters coated with gelatin. Pretreatment of endothelial cell cultures with 1 to 10 mumol/liter of beta-endorphin for 60 min resulted in significantly stimulated migration of subsequently added neutrophils across the endothelial monolayer. The number of neutrophils that migrated across beta-endorphin-treated endothelial cells was similar to the number that traversed untreated monolayers in response to gradients of formylpeptide. Consistently, an additive effect was seen when migration was induced by both beta-endorphin pretreatment of the endothelial cells and a formylpeptide chemotactic gradient. When used at optimal concentration, beta-endorphin was equally effective in stimulating neutrophil migration as was tumor necrosis factor-alpha. In the absence of formylpeptide the effect of apical surface exposure of endothelial cells to beta-endorphin versus basal surface exposure was comparable. Stimulation of neutrophil transendothelial migration in this system appeared to be specific and mediated by opiate receptors, since excess concentration of naloxone completely abolished the effect of beta-endorphin but not of tumor necrosis factor-alpha. These results suggest that beta-endorphin, released during stress, may act upon the endothelium to promote emigration of neutrophils from the vasculature.

Animals↗
PubMed1994

Human chorionic gonadotrophin: a chemoattractant for human blood monocytes, neutrophils and lymphocytes.

Treatment of rats with human chorionic gonadotrophin (hCG) induced in the testes an inflammation-like reaction characterized by migration of leukocytes into the interstitial space. In order to find out whether hCG acts in a direct manner in this process, we tested peripheral human blood leukocyte attraction by hCG in vitro. Chemotaxis through cellulose nitrate to gradients of test substances was measured using a 48-well microchemotaxis chamber. Human CG was found to be a potent attractor of neutrophils, monocytes and lymphocytes in vitro in the picomolar concentration range. Checkerboard analyses revealed that the type of migration depends on positive concentration gradients of hCG. The chemoattractant nature of hCG is consistent with its having a role to play in regulation of tissue accumulation of these cells within the reproductive tract.

Cells, Cultured↗
PubMed1993

Stimulation of the chemotactic migration of human fibroblasts by substance P.

Neuropeptides exert a variety of modulatory effects on inflammatory cellular responses. In order to investigate further activities of these cytokines on mechanisms in inflammatory processes, we determined the ability of substance P to promote human fibroblast chemotaxis. Cell migration was measured by two different assay types in modified Boyden chambers. Substance P was found to be a potent chemoattractant for human fibroblasts in vitro, eliciting a concentration-dependent migratory response. In further investigations we tested the chemoattractant potency of the fragments substance P-(1-4) and substance P-(3-11). As only the C-terminal analog promoted migratory responses, we suggest that the chemotactic responsiveness is largely encoded by the C-terminus of the neuropeptide, which is known to be active on neurokinin receptors. Involvement of neurokinin receptors of type 1 in the chemotactic response to substance P was indicated by fibroblast migration toward optimal concentration of a selective NK1 receptor agonist but not a NK2 receptor agonist. The observed ability of human fibroblasts to respond chemotactically to substance P elucidated another proinflammatory activity of this neuropeptide.

Amino Acid Sequence↗
PubMed1993

Attraction of human monocytes by the neuropeptide secretoneurin.

Secretoneurin is a newly discovered 33-amino-acid peptide derived from secretogranin II (chromogranin C) that is found in sensory afferent C-fibers. We show here that secretoneurin triggers the selective migration of human monocytes in vitro and in vivo. Combinations of secretoneurin with the sensory neuropeptides, substance P or somatostatin, synergistically stimulate such migration. The attraction of monocytes represents the first established function of secretoneurin as a sensory neuropeptide.

Animals↗
PubMed1993

Monocyte haptotaxis induced by the RANTES chemokine.

BACKGROUND: Soluble mediators and inducible cell-surface molecules coordinate the ordered cascade of events giving rise to inflammation. The specific mechanisms underlying the attraction of antigen-specific cells into a site of inflammation remain sketchy, however. In particular, it is unclear how chemoattractants cause rapidly moving immune cells to adhere to the blood vessel wall and to enter inflamed tissues. RESULTS: Here we show that RANTES, a potent chemo-attractant for monocytes and T lymphocytes, is inducibly expressed within an inflamed organ, binds to endothelial cells, and promotes haptotaxis, the migration of cells induced by surface-bound gradients. CONCLUSION: These findings lead us to propose a model for the role of RANTES in the migration of antigen-specific immune cells into an inflammatory site.

Journal Article↗
PubMed1993

Stimulation of monocyte chemotaxis by human growth hormone and its deactivation by somatostatin.

Monocyte infiltration occurs early in the course of inflammation and is a prerequisite for optimal repair of tissue damage. In this study, human recombinant growth hormone was shown to be a potent chemoattractant for human monocytes, inducing migration at picomolar concentrations of recombinant human growth hormone. Chemotaxis of monocytes was measured in vitro by a modified Boyden chamber assay using nitrocellulose micropore filters and measuring microscopically the migration depth of the leading front of monocytes. Somatostatin, which inhibits the release of growth hormone, and its long-acting analogue, octreotide, also stimulated chemotaxis of monocytes; however, the effective peptide concentration was in the micromolar range. When tested for chemotaxis in combination or in experiments using pretreatment with somatostatin and washing of treated cells, somatostatin significantly antagonized the chemotactic responses of monocytes to growth hormone. The inhibitory effect on growth hormone-stimulated chemotaxis was dose dependent and occurred at concentrations severalfold lower than the chemotactically active concentration of somatostatin. Combinations of growth hormone with interferon or substance P also deactivated the chemotactic responses. These observations suggest that human growth hormone may have a regulatory role in monocyte chemotaxis.

Chemotaxis, Leukocyte↗
PubMed1993

Induction of circulating IL-1 receptor antagonist by IFN treatment.

This study was undertaken to determine whether IFN induce IL-1 receptor antagonist (IL-1Ra), a specific inhibitor of IL-1. Plasma samples were obtained from healthy volunteers (n = 5) and patients with chronic hepatitis C (n = 5) treated with IFN-alpha, and from patients with renal cell carcinoma (n = 6) treated with IFN-gamma and assayed for IL-1Ra by a specific radioimmunoassay. Both types of IFN were administered subcutaneously. In vitro studies were carried out with PBMC from healthy volunteers. A single, low and nontoxic dose (1 x 10(6) U) of IFN-alpha induced circulating IL-1Ra, which reached peak levels within 12 h. This effect was dose-dependent and more pronounced with a higher dose (5 x 10(6) U). Peak IL-1Ra levels 12 h after 5 x 10(6) U IFN-alpha were 4.16 +/- 0.35 ng/ml in healthy volunteers and 5.7 +/- 0.73 ng/ml in patients with chronic hepatitis C (difference not significant). Thereafter levels declined but remained elevated for 24 h. IFN-gamma treatment led only to a modest increase of circulating IL-1Ra even at a dose of 400 micrograms; this dose, however, was associated with side effects similar to those seen after injection of 5 x 10(6) U IFN-alpha. PBMC stimulated with IFN-alpha or IFN-gamma produced IL-1Ra in vitro. The induction of IL-1Ra may contribute to the antiviral, anti-inflammatory, and antiproliferative effects of IFN.

Carcinoma, Renal Cell↗
PubMed1993

Substance P: a competence factor for human fibroblast proliferation that induces the release of growth-regulatory arachidonic acid metabolites.

Substance P (SP) was recognized to stimulate cell growth. The mechanisms of growth control by SP are unknown. We, therefore, investigated mechanisms of the effect of SP on proliferation of human skin fibroblasts. SP did not stimulate proliferation of fibroblasts growth arrested by serum starvation over 48 hours. However, in the presence of acetylsalicylic acid SP potently stimulated fibroblast growth. A bell-shaped dose-response curve with maximal stimulation at picomolar concentrations was found. Specificity of the mitogenic effect was analyzed by use of synthetic SP analogs. Only neurokinin-1 receptor agonists were active, whereas a specific neurokinin-2 receptor analog did not exhibit mitogenicity. Analyzing the supernatants of growth-arrested fibroblasts treated with SP indicated that SP provokes release of the arachidonic acid metabolites, prostaglandin E2, and prostacyclin but not thromboxane B2 or leukotriene B4. Since similar response patterns in proliferation and arachidonic acid metabolite release have been described for several proinflammatory cytokines, some of which are known to act as competence factors in proliferation, we characterized the mitogenic effect of SP. Results established that SP stimulates fibroblast growth in a manner typical of competence factors. We conclude that arachidonic acid metabolites are involved in the cell cycle-dependent mitogenic action of SP on human skin fibroblasts.

Arachidonic Acid↗
PubMed1993

Inhibition of recombinant human growth hormone-induced and prolactin-induced activation of neutrophils by octreotide.

Growth hormone, prolactin and somatostatin are polypeptide hormones of the neuroendocrine and peripheral nervous systems. In vitro, these have opposing effects on cells of the immune system. We compared the effects of these peptides on activation of neutrophils using a recombinant preparation of human growth hormone, human prolactin and octreotide, a long acting analog of somatostatin. In the absence of growth hormone, octreotide did not affect either neutrophil locomotion or respiratory burst. Octreotide, however, significantly antagonized growth hormone-induced activation of neutrophils for enhanced respiratory burst as well as growth hormone-induced inhibition of stimulated migration. As the effect of growth hormone on neutrophils is mediated by the prolactin receptor, its inhibition by octreotide was also tested using prolactin as priming agent. Data indicate comparable effects of octreotide on priming of neutrophils by prolactin. The effect of octreotide was dose-dependent and appeared to be selective, as activation of neutrophil respiration burst by gamma-interferon, and inhibition of stimulated migration by tumor necrosis factor-alpha were unaffected by octreotide. The present study suggests that octreotide may act on neutrophils directly by antagonizing growth hormone or prolactin at the cellular level.

Chemotaxis, Leukocyte↗
PubMed1993

Inhibition of superoxide anion release from circulating neutrophils by L-arginine in man.

In animal studies of myocardial ischemia/reperfusion L-arginine reduces necrotic injury by preservation of endothelial function and attenuation of neutrophil accumulation in ischemic cardiac tissue. Because release of oxygen radical species by circulating neutrophils is important in endothelial function and ischemia-reperfusion injury, this study investigated the effect of intravenous administration of L-arginine on the in vitro release of superoxide anion of neutrophils in healthy young adults. Neutrophils were obtained at various time points before, during, and after infusion of L-arginine (17 mg kg-1 min-1 for 30 min) and analyzed for superoxide dismutase inhibitable reduction of ferricytochrome c. The spontaneously occurring respiratory burst of polymorphonuclear leukocytes at basal conditions was compared with that after triggering by 1 mumol/l formylpeptide or 50 ng/ml phorbolester. Infusion of L-arginine inhibited both basal (P < 0.01) and formylpeptide-triggered (P < 0.05) release of superoxide anion did, but not affect release stimulated by phorbol 12-myristate 13-acetate. Pretreatment of neutrophils with 1 mmol/l L-arginine in vitro also significantly reduced formylpeptide-triggered (1 mumol/l) superoxide anion release, suggesting that the affects observed after in vivo pretreatment may be due to direct action of L-arginine on neutrophils. These findings demonstrate the ability of L-arginine to reduce release of oxygen radical species by circulating neutrophils in man.

Adult↗