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Biomedical subjects

A Kurdowska

Publications and source records attributed to A Kurdowska.

32 records · Page 2Linked to original sources
PubMed1988

Effects of dexamethasone and insulin on the acute phase response of Morris hepatoma cells and of rat hepatocytes in culture.

Dexamethasone and insulin stimulate production of several plasma proteins in primary cultures of adult rat hepatocytes but inhibit their production in primary cultures of Morris hepatoma cell line 7777W. The acute phase response elicited in cultured cells by crude cytokines from activated rat peritoneal macrophages is considerably higher in hepatocytes in the presence of hormones, and especially of dexamethasone. In hepatoma cells the hormones enhance the cytokine-induced formation of fibrinogen and cysteine proteinase inhibitor but are without significant effect on suppression of albumin and alpha-fetoprotein synthesis by macrophage supernatants.

Acute-Phase Proteins↗
PubMed1988

The cascade of inflammatory cytokines regulating synthesis of acute phase proteins.

The acute phase cytokines: interleukin 1, tumor necrosis factor alpha (cachectin) and beta (lymphotoxin), hepatocyte stimulating factor and several interferons, all belong to the family of endotoxin-inducible, low molecular weight proteins. Their synthesis in macrophages, fibroblasts, lymphocytes, epithelial and some tumor cells is enhanced by the same cytokines, often in the autocrine manner, and suppressed by dexamethasone. The principal hepatocyte stimulating factor (HSF) regulating synthesis of acute phase proteins is probably identical with IFN-beta 2/BSF-2/IL-6, but other inflammatory cytokines (IL-1, TNF alpha, IFN-gamma) are able to induce distinct sets of acute phase proteins, or to modulate the final response pattern. The effect of hrIFN-gamma on production of acute phase proteins by human hepatoma Hep G2 cells is discussed in detail. It is concluded that the cascades of inflammatory cytokines in different tissues represent amplification and regulatory pathways controlling the development of acute phase response in vivo.

Acute-Phase Proteins↗
PubMed1987

Comparison of the acute phase response of cultured Morris hepatoma 7777 cells and of rat hepatocytes.

Isolated Morris hepatoma cells (line 7777) or adult rat hepatocytes were cultured for 3 days and daily production of four plasma proteins was estimated in the cell media by rocket immunoelectrophoresis with monospecific antisera. Addition of cytokines from rat peritoneal macrophages to cultured hepatocytes or hepatoma cells augmented accumulation in the medium of two positive acute phase proteins: fibrinogen (FIB) and cysteine proteinase inhibitor (CPI). At the same time synthesis of alpha-fetoprotein (AFP) was inhibited in hepatoma cells but remained undetectable in hepatocytes. Rat macrophage cytokines typically depressed synthesis of albumin (ALB) in cultured rat hepatocytes but increased production of this protein by hepatoma cells.

Acute-Phase Proteins↗
PubMed1987

Limited effects of recombinant human and murine interleukin 1 and tumour necrosis factor on production of acute phase proteins by cultured rat hepatocytes.

Albumin, fibrinogen, alpha 1-acid glycoprotein and cysteine proteinase inhibitor were determined by electroimmunoassay in the media of primary cultures of rat hepatocytes exposed to dialysed supernatants of rat, mouse and human macrophages or to recombinant human and murine interleukin 1 and tumour necrosis factor. Recombinant cytokines in the range of 1 to 1000 ng/ml caused only reduction of albumin synthesis and slight stimulation of alpha 1 acid glycoprotein production while crude preparations of macrophage cytokines elicited typical acute phase response. The results suggest that interleukin 1 or tumour necrosis factor are not likely the principal mediators responsible for the direct stimulation of normal rat hepatocytes to acute phase protein synthesis.

Animals↗
PubMed1986

Comparison of antiproteolytic activities of alpha-1-proteinase inhibitors from the plasma of some mammalian species.

Alpha-1-proteinase inhibitors isolated from plasmas of horse, ox, pig, rabbit and man were used for determination of some kinetic parameters of interaction with three horse leucocyte proteinases and bovine pancreatic trypsin and chymotrypsin. Effective molar ratio of enzyme-to-inhibitor, inactivation rate constant and inhibition constant were measured. In horse, ox, pig and rabbit two principal electrophoretic forms of alpha 1-PI could be distinguished. Both forms effectively inhibited trypsin but usually only one form reacted promptly and stoichiometrically with chymotrypsin and leucocyte elastases. It appears that genetic variability and functional heterogeneity of multiple forms of alpha 1-PI as well as lack of other tissue inhibitors of proteinases may be responsible for lung emphysema occurring in man and horse.

Animals↗
PubMed1986

Alpha-1-acute phase globulin in the blood of tunicamycin-injected rats. Isolation of the non-glycosylated form, its inhibitory properties and synthesis in liver slices.

Plasma of rats injected with tunicamycin (2 micrograms/g body wt) shows on crossed immunoelectrophoresis the presence of an additional, slowly migrating component of alpha 1-acute-phase globulin (alpha 1-AP-globulin). The native and modified forms of alpha 1-AP-globulin were jointly isolated on the column of immobilized antibodies and then separated by chromatofocusing on polybuffer exchanger. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate demonstrated that tunicamycin-induced form of rat alpha 1-AP-globulin has Mr of 50,000 and is devoid of carbohydrates as inferred from the lack of staining with Schiff reagent. However, during incubation with papain in vitro it is only slightly less effective than mature glycosylated alpha 1-AP-globulin (Mr 68 000) in inhibiting hydrolysis of CBZ-Lys-ONp. Incubation of liver slices from control and tunicamycin-injected rats with 14C-leucine demonstrated that tunicamycin reduces synthesis and release to the medium of alpha 1-AP-globulin and some other plasma proteins, but the proportion of aglyco-alpha 1-AP-globulin is higher than in plasma.

Acute-Phase Proteins↗
PubMed1985

Biosynthesis and secretion of alpha 1 acute-phase globulin in primary cultures of rat hepatocytes.

Experimental inflammation in rats led to a sevenfold increase in serum levels of alpha 1 acute-phase globulin. This increase is correlated with elevated levels of translatable mRNA for alpha 1 acute-phase globulin in the liver. Biosynthesis and secretion of alpha 1 acute-phase globulin were studied in rat hepatocyte primary cultures. An intracellular form of alpha 1 acute-phase globulin with an apparent relative molecular mass of 63 500 and a secreted form of 68 000 were found. The intracellular form of alpha 1 acute-phase globulin could be deglycosylated by endoglucosaminidase H treatment indicating that its oligosaccharide chains were of the high-mannose type. The secreted form of alpha 1 acute-phase globulin was not sensitive to endoglucosaminidase H, but was susceptible to the action of sialidase reflecting carbohydrate side-chains of the complex type. Pulse-chase experiments revealed a precursor-product relationship for the high-mannose and the complex type alpha 1 acute-phase globulin. In the hepatocyte medium newly synthesized alpha 1 acute-phase globulin was detected 30 min after the pulse. Unglycosylated alpha 1 acute-phase globulin was found in the cells as well as in the medium when the transfer of oligosaccharide chains onto the polypeptide chains was blocked by tunicamycin. Tunicamycin led to a marked delay in alpha 1 acute-phase globulin secretion.

Animals↗
PubMed1983

Kinetics and stoichiometry of inactivation of some pancreatic and leucocyte serine proteinases by rabbit alpha 1-proteinase inhibitors F and S.

Purified rabbit alpha 1-proteinase inhibitors F and S were incubated with bovine trypsin, chymotrypsin or horse leucocyte neutral proteinases in order to determine the stoichiometry of inhibition, inactivation rates of the enzymes and dissociation constants of the complexes. Trypsin reacted with the two forms of alpha 1-PI with different velocities but in the molar ratio of 1:1 and yielding stable complexes. Chymotrypsin reacted very fast with the two forms of alpha 1-PI but required a three-fold molar excess of alpha 1-PI-S for almost complete inhibition, and again the dissociation constants were low. Leucocyte proteinases also needed certain molar excess of the inhibitor but the reaction was complicated by instability of the complexes, especially with Z-Ala-ONp as substrate. We conclude that the interaction of rabbit alpha 1-PI with leucocyte proteinases, and particularly alpha 1-PI-S with chymotrypsin, includes not only complex formation but also some inactivation of the inhibitor.

Animals↗
PubMed1981

Interaction of horse plasma antithrombin III and alpha 1-proteinase inhibitor with some serine proteinases.

Antithrombin III and alpha 1-proteinase inhibitor isolated simultaneously from horse citrated plasma were tested for inhibitory activity against bovine trypsin and chymotrypsin, as well as elastase-like neutral proteinases from horse leucocytes. The stoichiometry of reaction and kinetic parameters (kass, Ko) were estimated and related to the protein pattern obtained after exposure of these proteinases to horse inhibitors as analyzed by polyacrylamide gel electrophoresis (PAGE and PAGE-SDS). As shown by fast reaction rates and low values of dissociation constants the two inhibitors effectively inactivate trypsin. On the other hand, AT III is completely inactive against chymotrypsin or leucocyte elastases with alpha 1PI only partly inhibits these enzymes.

Animals↗