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K Decker

Publications and source records attributed to K Decker.

At least 145 records · Page 8Linked to original sources
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↗
PubMed1985

Toxicity of D-galactosamine for rat hepatocytes in monolayer culture.

Hepatocellular injury was induced by exposure of primary cultures of rat hepatocytes to 4 mM D-galactosamine. The cell damage was very similar to that seen in vivo and in the isolated perfused rat liver, both in biochemical and in structural terms. The severity of the lesions caused by D-galactosamine was dependent on the age of the culture being treated. Less severe damage was found with older cultures. Since the primary metabolic effects of D-galactosamine were age-independent, the reduction in cell damage seems to be due to progressive cell dedifferentiation. Dexamethasone (1 microM) suppressed the full development of the injury, while 1 microM triiodo-L-thyronine enhanced it. A protection of hepatocytes by alpha 2-macroglobulin against the effects of D-galactosamine could be observed neither in vivo nor in vitro. Direct cytotoxic effects of endotoxin from Salmonella minnesota R 595 could be demonstrated only on hepatocytes in the early phases of primary culture using rather high doses of the purified lipopolysaccharide. It is unlikely that they play a major role in the hepatocellular injury seen following endotoxinemia in vivo. Lowering of extracellular Ca2+ concentration and additions of calcium/calmodulin inhibitors did not prevent cell injury after treatment with D-galactosamine. The results suggest that cell death is not due to an increased influx of Ca2+ into the cells.

Albumins↗
PubMed1985

Cellular regulation of poly(ADP) ribosylation of proteins. I. Comparison of hepatocytes, cultured cells and liver nuclei and the influence of varying concentrations of NAD.

The in vitro rates (vinit) of poly(ADP-ribose) polymerase of permeabilized rat hepatocytes and of nuclei, isolated from hepatocytes, did not differ significantly. Incubation beyond 3 min resulted in diminished poly(ADP) ribosylation in hepatocytes compared with nuclei, coinciding with high rates of plasma membrane-associated NAD-glycohydrolase. Cultured cells (Drosophila Kc cells, gliosarcoma 9L, human fibroblasts and mouse spleen lymphocytes) exhibit variations of NAD-glycohydrolase and poly(ADP-ribose) polymerase activities and the assessment of poly(ADP-ribose) polymerase activity in permeabilized cells requires simultaneous assay of NAD-glycohydrolase. In rat liver nuclei during 10 min incubation with 500 microM NAD, 40% of NAD is consumed, 10% ADP-ribose is bound to proteins, and 20% ADP-ribose, 5% AMP and 2.7% adenosine are liberated. As determined by solvent partitioning (Jackowski, G & Kun, E, J biol chem 258 (1983) 12587) [1], the phenol-soluble protein-ADP-ribose fraction represents largely mono(ADP)-ribose protein adducts, whereas the H2O-soluble phase contains poly(ADP)-ribosylated proteins. The quantity of ADP-ribose protein adducts, the chain length of oligomers and the nature of apparent acceptor proteins in liver nuclei vary significantly with the concentration of NAD as substrate. At 500 microM NAD concentration the quantity of ADP-ribose containing adducts was in the nmol per mg DNA range, the polymers are long chains and the acceptor proteins predominantly non-histone proteins. At 0.1 microM NAD as substrate pmol quantities of monomeric ADP-ribose adducts per mg DNA were formed and the main acceptors were sharply discernable on the basis of molecular mass as histones, high mobility non-histone proteins, two protein groups of a mass of 66 and 44 kD respectively, and the poly(ADP-ribose) polymerase enzyme protein of 119 kD mass. Whereas products in the presence of 0.1 microM NAD may indicate acceptors of highest reactivity, protein adducts formed in the presence of 500 microM NAD resemble a pattern found in vivo.

ADP Ribose Transferases↗
PubMed1985

[Nonpuerperal mastitis].

The medical history of 37 women with nonpuerperal mastitis, who had been treated between January 1980 and July 1983 at the Dept. of Obstetrics and Gynaecology of the University of Tübingen, was reviewed because of the increasing prevalence of this disease. Defined by different history and clinical symptoms, two groups of patients were seen: 25 women with acute nonpuerperal mastitis and 12 women with chronic recurring nonpuerperal mastitis. The average age of the patients was 30 years. The inflammation was located mostly subareolar and around the nipple. The main symptoms were pain, erythema and swelling, in acute cases accompanied by fever and abscess formation. This process was strongly related to the interval between the onset of symptoms and the initiation of treatment. Anaerobes and Staphylococcus aureus could be cultured mainly from women with acute nonpuerperal mastitis. In females with chronic recurrent mastitis, mostly anaerobes were found. Women were treated with a prolactin inhibitor (bromocriptine), if abscess formation, leukocytosis or fever were absent. In patients with leukocytosis and/or fever this regimen was combined with antibiotics. Abscesses were treated surgically, in some cases in combination with prolactin inhibition and antibiotic administration. The results show that an early conservative treatment is important to prevent abscess formation. It seems that this treatment can reduce the rate of recurrences.

Abscess↗
PubMed1985

[Nuclear magnetic resonance tomography of the spine].

The present paper deals with the results of 48 MR examinations of known spinal abnormalities. The use of a method strictly related to the individual problem helps to reduce the duration of the examination. Sagittal cuts are particularly useful for demonstrating much of the spinal canal. The spin-echo method is used for all examinations. Demonstration of the cord was performed by using short repetition and echo times (TR, TE). For showing the outer margin of the spinal canal, longer TR and TE should be selected. Surface coils are important for demonstrating spinal disease, since the larger images can be performed without increasing the duration of the examination.

Humans↗
PubMed1985

Eicosanoids, signal molecules of liver cells.

The information that has been accumulated in recent years about metabolism and function of eicosanoids in the liver does not yet allow the presentation of a comprehensive picture. It suffices, however, to attribute to these mediators an important role in signal transduction between the different cells of the liver, especially in inflammatory reactions, in immunologic disorders, and in septic shock. Much knowledge has been gained in recent years about the biochemistry and physiology of eicosanoids in many other tissues; the methodology of the analysis of eicosanoids, their metabolites, and their cellular functions is rapidly improving. This will assist in the elucidation of the signal functions of arachidonic acid derivatives in the liver.

Animals↗
PubMed1985

Content and accessibility of sialic acid on the surface of rat hepatocytes during primary culture.

The content and accessibility of terminal sialic acid and galactose residues of rat hepatocytes in primary culture were determined by in situ labeling using either periodate or sialidase/galactose oxidase treatment followed by sodium borotritiide reduction. Rat erythrocytes which were used for comparison showed a strongly enhanced tritium incorporation into galactose after sialidase treatment. In contrast, with freshly prepared rat hepatocytes only a small amount of galactose labeling was achieved after sialidase treatment. The amount of galactose labeled following sialidase treatment increased with time in culture up to day 6 and roughly paralleled the increase of the total sialic acid content. Major changes of sialic acid-containing glycoconjugates were restricted to the gangliosides. There was a transient drop in surface labeling of ganglioside-associated sialic acid on the first day in culture. The specific radioactivity of the in situ-tritiated ganglioside-sialic acid also fell by 50% in this period. Between day 2 and 4, there was an increase in gangliosidesialic acid labeling but the specific radioactivity of the sialic acid remained constant. This indicates that newly synthesized gangliosides but not the preexisting ones were accessible to periodate oxidation. The data allow conclusions about turnover and topology of the sialic acid-containing glycolipids.

Animals↗
PubMed1985

Age- and hormone-dependent ganglioside patterns of rat hepatocytes in primary culture.

Using an improved procedure for the quantitative extraction of all glycolipids from small tissue samples the hepatic ganglioside pattern of rats was analysed during development. While this parameter remained fairly constant in adult animals, hepatocytes in primary culture showed drastic changes both in content and relative distribution among the various ganglioside species. The content of lipid-bound sialic acid increased several-fold during 6 days in monolayer and the pattern changed in favour of the higher sialylated forms. Dexamethasone delayed this transition and enhanced the content of GD1a and GM1 relative to GM3. The ganglioside content was also dependent on the density of hepatocytes in the primary culture. If the cell density was insufficient for formation of a confluent monolayer, higher ganglioside-sialic acid contents were found and the relative amount of GD3 increased after 3-4 days. These results support the notion that gangliosides are involved in cellular differentiation and cell-cell contact.

Aging↗
PubMed1984

Induction of rat alpha 2-macroglobulin in vivo and in hepatocyte primary cultures: synergistic action of glucocorticoids and a Kupffer cell-derived factor.

Turpentine injection into rats elicits enhanced secretion of acute phase proteins including alpha 2-macroglobulin (alpha 2M). Hypophysectomized rats, however, do not respond in this way unless dexamethasone is given together with turpentine. On the other hand, dexamethasone injection alone did not result in an induction of alpha 2M synthesis. When a medium of Kupffer cell cultures was added to hepatocytes, a dose-dependent stimulation of alpha 2M synthesis of up to 4-fold after 10-12 h was observed. However, the presence of low concentrations (10(-9)M) of dexamethasone was essential for the stimulatory effect. We conclude that the acute phase induction of alpha 2M in hepatocytes requires the synergistic action of glucocorticoids and a non-dialysable factor secreted by Kupffer cells.

Animals↗
PubMed1984

In vitro alkylation of calf thymus DNA by acrylonitrile. Isolation of cyanoethyl-adducts of guanine and thymine and carboxyethyl-adducts of adenine and cytosine.

Reaction of the rodent carcinogen acrylonitrile (AN) at pH 5.0 and/or pH 7.0 for 10 and/or 40 days with 2'-deoxyadenosine (dAdo), 2'-deoxycytidine (dCyd), 2'-deoxyguanosine (dGuo), 2'-deoxyinosine (dIno), N6-methyl-2'-deoxyadenosine (N6-Me-dAdo) and thymidine (dThd) resulted in the formation of cyanoethyl and carboxyethyl adducts. Adducts were not detected after 4 h. The adducts isolated were 1-(2-carboxyethyl)-dAdo (1-CE-dAdo), N6-CE-dAdo, 3-CE-dCyd, 7-(2-cyanoethyl)-Gua (7-CNE-Gua), 7,9-bis-CNE-Gua, imidazole ring-opened 7,9-bis-CNE-Gua, 1-CNE-dIno, 1-CE-N6-Me-dAdo and 3-CNE-dThd. Structures were assigned on the basis of UV spectra and electron impact (EI), chemical ionization (CI), desorption chemical ionization (DCI) and Californium-252 fission fragment ionization mass spectra. Evidence is presented which strongly suggests that N6-CE-dAdo was formed by Dimroth rearrangement of 1-CE-dAdo during the reaction between AN and dAdo. The carboxyethyl adducts resulted from initial cyanoethylation (by Michael addition) at a ring nitrogen adjacent to an exocyclic nitrogen atom followed by rapid hydrolysis of the nitrile moiety to a carboxylic acid. It was postulated that the facile hydrolysis is an autocatalyzed reaction resulting from the formation of a cyclic intermediate between nitrile carbon and exocyclic nitrogen. AN was reacted with calf thymus DNA (pH 7.0, 37 degrees C, 40 days) and the relative amounts of adducts isolated were 1-CE-Ade (26%), N6-CE-Ade (8%), 3-CE-Cyt (1%), 7-CNE-Gua (26%), 7,9-bis-CNE-Gua (4%), imidazole ring-opened 7,9-bis-CNE-Gua (19%) and 3-CNE-Thy (16%). Thus a carcinogen once adducted to a base in DNA was shown to be subsequently modified resulting in a mixed pattern of cyanoethylated and carboxyethylated AN-DNA adducts. Three of the adducts (1-CE-Ade, N6-CE-Ade and 3-CE-Cyt) were identical to adducts previously reported by us to be formed following in vitro reaction of the carcinogen beta-propiolactone (BPL) and calf thymus DNA. The results demonstrate that AN can directly alkylate DNA in vitro at a physiological pH and temperature.

Acrylonitrile↗
PubMed1984

Synthesis of prostanoids and cyclic nucleotides by phagocytosing rat Kupffer cells.

Rat Kupffer cells in monolayer culture were allowed to phagocytose unopsonized zymosan granules. They responded with a strongly stimulated synthesis and release of prostanoids, mainly the immunologically determined prostaglandins PGE2 and PGF2 alpha. The same response could be obtained by treatment with the calcium ionophore A23187. The effects of the ionophore and the zymosan particles were of the same magnitude but not additive. The rapid uptake of Ca2+ after contact with phagocytosable material recently described by us [(1983) Eur. J. Biochem. 131, 539-543] appears to mediate the enhanced prostaglandin synthesis. That response was suppressed not only by indomethacin but also by trifluoperazine which does not inhibit Ca2+ entry in the Kupffer cells. Similar effects by R24571 and 4-bromophenacyl bromide support the participation of calcium-calmodulin and of phospholipase A2. The calcium channel blocker Verapamil did not influence the zymosan-provoked production of prostaglandin PGE2 nor were any indications obtained for a feedback inhibition by PGE1 or PGE2. Contact with zymosan resulted in a rapid but transient rise of the intracellular levels of cAMP and cGMP: 10 nM indomethacin completely blocked the increase of both cyclic nucleotides while trifluoperazine elicited different responses in the cAMP and cGMP levels. The stimulated release of prostaglandin E2 was inhibited in a dose-dependent manner by nordihydroguaiaretic acid, an inhibitor of 5-lipoxygenase and by FPL 55712, known as a receptor antagonist for some leukotrienes. This suggests a regulatory role for its metabolites on prostaglandin synthesis.

Animals↗
PubMed1984

Calmodulin content and activity of Ca2+-ATPase and phospholipase A2 in rat Kupffer cells.

A protein resembling calmodulin was isolated from non-parenchymal and parenchymal cells of rat liver by affinity chromatography. The biological activity of the purified protein was assessed by the bovine brain cAMP phosphodiesterase assay. A highly sensitive radioimmunoassay as well as the cAMP phosphodiesterase method were employed to determine the calmodulin content of crude extracts from monolayer cultures of rat Kupffer cells and hepatocytes. An ATP-dependent, calmodulin-enhanced calcium transport was demonstrated in a membrane fraction of the non-parenchymal cells. Phospholipase A2 activity specific for 2-arachidonoyl phosphatide and with a pH optimum of 8.1 was measured in homogenized Kupffer cells; it was stimulated by agents previously shown to enhance prostaglandin synthesis in Kupffer cells, e.g. zymosan particles and lipopolysaccharide isolated from Salmonella minnesota. The increase in activity was completely prevented by pretreatment with or simultaneous addition of R 24571, a known calmodulin antagonist. However, if this inhibitor or calmodulin was added to the cell-free extract phospholipase A2 activity was not influenced. Phospholipase A1 activity could be detected at pH 5 only, showing a slight decrease in the homogenate of stimulated macrophages. Acyltransferase activity was high but independent of treatment of the Kupffer cells.

1-Acylglycerophosphocholine O-Acyltransferase↗
PubMed1984

Isolation and partial characterization of plasmid DNA from Arthrobacter oxidans.

A method for the extraction of the high molecular weight plasmid AO 1 from the gram-positive soil bacterium Arthrobacter oxidans is presented. Following digestion of this DNA with the restriction endonucleases AccI, Bam HI, Eco RI and Hind III, an average molecular mass of 157.8 kb was estimated. This value is in good agreement with the 160 kb size determined previously by electron microscopy (Brandsch et al. 1982). Using the same method, no plasmid DNA was found in strains of the genus Arthrobacter which do not degrade nicotine, e.g., A. albidus, A. globiformis and A. auricans.

Arthrobacter↗
PubMed1984

Induction of acute phase proteins by dexamethasone in rat hepatocyte primary cultures.

The effect of dexamethasone on the synthesis of acute phase proteins has been studied in primary cultures of rat hepatocytes. In the absence of dexamethasone no detectable amounts of alpha 2-macroglobulin were synthesized by hepatocytes cultured for 1 day. alpha 2-Macroglobulin synthesis was induced by dexamethasone concentrations of 10(-8) M or higher with a maximum at a concentration of 10(-7) M. alpha 1-Acid glycoprotein was synthesized in the absence of dexamethasone; however, its synthesis was also greatly stimulated by dexamethasone concentrations of 10(-8)-10(-6) M. Synthesis of alpha 1-proteinase inhibitor was stimulated only 1.4-fold at a dexamethasone concentration of 10(-7) M. The kinetics of induction of alpha 2-macroglobulin and alpha 1-acid glycoprotein were studied at a dexamethasone concentration of 10(-7) M. After an initial lag phase of 3 h the synthesis of both proteins showed a steady increase during 2 days. Synthesis of albumin remained unchanged under these experimental conditions. Unlike alpha 2-macroglobulin and alpha 1-acid glycoprotein tyrosine aminotransferase activity increased already during the first 3 h of induction by dexamethasone with a maximum at 12 h followed by a slight decrease.

Acute-Phase Proteins↗
PubMed1984

Phagocytosis of hepatocyte mitochondria by rat Kupffer cells in vitro.

Kupffer cells in primary culture bind and endocytose rapidly added rat liver mitochondria. Using phase contrast microscopy various stages of the uptake and digestion of these organelles were documented. Activities of mitochondrial enzymes within the Kupffer cells increased during the early phase of phagocytosis; they later declined, reaching the endogenous level of the Kupffer cell mitochondria after 3 to 4 h. The uptake was enhanced in the presence of heparin or rat serum, while iodoacetate, cytochalasin B or anti-fibronectin antisera were inhibitory. The transient presence of enzymatically active hepatocyte mitochondria renders Kupffer cells capable of producing urea. This mechanism partially explains earlier observations of urea formation in non-parenchymal rat liver cells.

Animals↗
PubMed1984

On the mechanism of lactate dehydrogenase leakage from normal and D-galactosamine-treated hepatocytes in monolayer culture.

Synthesis, degradation and leakage of lactate dehydrogenase and of total protein was measured using D-galactosamine-treated rat hepatocytes in monolayer culture. The kinetics of [3H]leucine incorporation into trichloroacetic acid-precipitable material and into isolated lactate dehydrogenase of cells and of the extra-cellular space revealed a similar extent of inhibition of both synthesis and leakage following exposure to D-galactosamine. Hepatocyte cultures that had been labeled before D-galactosamine treatment lost intracellular protein-associated radioactivity almost as rapidly as control cells up to the time of measurable enzyme leakage; thereafter, the rate of 3H-loss increased in the treated cells. Lactate dehydrogenase present in the medium is degraded less rapidly than the enzyme in the intracellular space. This explains the apparent increase of total lactate dehydrogenase activity in D-galactosamine-treated as compared to control cultures. Following [3H]leucine addition to D-galactosamine-treated cultures, the specific radioactivity of the leaked lactate dehydrogenase in the medium was never greater than that of the enzyme in the cytosolic compartment. The data rule out a direct excretion of newly synthesized enzyme as a result of D-galactosamine action.

Animals↗