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PubMedDate not supplied

Additive therapeutic effects of the liver extract preparation mixture adelavin-9 on interferon-beta treatment for chronic hepatitis C.

BACKGROUND/AIMS: We previously reported that intravenous interferon-beta administration was effective in treating patients with chronic hepatitis C and that there was no significant correlation between the response to therapy and host in vitro immunoglobulin production. The aims of this study were to evaluate the additive effect of a liver extract preparation and flavin adenine dinucleotide mixture and to reevaluate the correlation. METHODOLOGY: 65 patients with chronic hepatitis C received intravenously 6 million units of interferon-beta and 2 mL of a liver extract preparation and flavin adenine dinucleotide mixture. The results of this study were compared with those of our previous study, on interferon-beta monotherapy in 91 patients with chronic hepatitis C. In addition, peripheral blood mononuclear cells were obtained before interferon-beta administration and cultured. Immunoglobulin concentrations in their supernatants were measured and the correlation with the interferon response was evaluated. RESULTS: The virological end-of-treatment or sustained response occurred in 49 of 58 cases (84.5%), and 16 of 58 cases (27.6%), respectively. Biochemical end-of-treatment or sustained responses occurred in 22 of 58 cases (37.9%), and 30 of 58 cases (51.7%), respectively. These response rates were higher than those reported in our previous study of interferon monotherapy. Monovariate analysis indicated that the use of the liver extract preparation and flavin adenine dinucleotide mixture was a significant predictor of the virological end-of-treatment response and the sustained biochemical response, but by multivariate analysis these relationships were not significant. Immunoglobulin production was not correlated with the virological and biochemical responses. CONCLUSIONS: This study indicated that combination therapy with intravenous interferon-beta and the liver extract preparation and flavin adenine dinucleotide mixture was more effective than intravenous interferon-beta monotherapy. However, no correlation between the interferon response and in vitro immunoglobulin production was observed.

Adult↗
PubMed1991

1H NMR analyses of methyl group-containing metabolites in rat liver extracts--effects of starvation, anoxia, acute glycerol and carbon tetrachloride treatment and chronic ethanol administration on hepatic metabolism.

400 MHz 1H NMR spectroscopy was used to analyze methyl group-containing metabolites in perchloric acid extracts of livers of rats treated with carbon tetrachloride or fed with ethanol-containing liquid diets, and sacrificed with carbon dioxide anoxic euthanasia or pentobarbital euthanasia (with or without 12-18 hour fasting). In all cases, coenzyme A was detected using 1H NMR spectroscopy, but at higher levels for chronic ethanol-treated rats. Propionate was also detected in livers 6 hours after treatment with carbon tetrachloride. The assignments of the 1H NMR resonances in a spectrum of biological origin to these two metabolites have not been previously reported. Another unusual metabolite, 1,2-propanediol, was also observed in dramatically elevated levels in starved rats. The methyl groups for coenzyme A, propionate, and 1,2-propanediol have 1H NMR chemical shifts at 0.73 and 0.87 ppm, 1.18 ppm, and 1.14 ppm (from tetramethylsilane) respectively. In addition to the above mentioned resonances, glutamine, glutamate, proline, acetate, leucine, alanine, lactate, ethanol, beta-hydroxybutyrate, and valine were also observed in the 0.5-2.3 ppm methyl region of the 1H NMR spectra. Biochemical changes were also observed in these latter metabolites. beta-Hydroxybutyrate was increased by chronic ethanol administration; this increase was exacerbated by starvation. Alanine was decreased by chronic ethanol administration. Acetate was increased by chronic ethanol administration except when glycerol was added to the liver or when the rat was starved. We also observed an unassigned triplet at 0.81 ppm, and its appearance seems to be correlated with that of 1,2-propanediol.

Amino Acids↗
PubMed1976

Vinyl chloride dependent mutagensis: effects of liver extracts and free radicals.

The mutagenic effects of vinyl chloride (VC) on Salmonella typhimurium strain TA1530 are enhanced by mouse or rat liver extracts. The extracts prepared from mice pretreated either with vinyl chloride or the microsomal enzyme inducer, Aroclor 1254, did not produce any greater stimulation of VC-dependent mutagenesis than extracts from untreated animals. These same extracts, however, differed markedly in their capacity to stimulate the mutagenicity of dimethylnitrosamine (DMN), a compound which is converted to a mutagen by an NADPH dependent microsomal mixed function oxidase. The order of activity of the extracts with DMN was Aroclor pretreated is greater than untreated is greater than VC pretreated. Furthermore, the stimulatory effect of the liver extracts on VC mediated mutagenesis did not require NADPH and was still evident in liver extracts in which the microsomal mixed function oxidase system had been heat inactivated. The mutagenic activity of VC also was found to be stimulated by riboflavin in the presence of light suggesting that free radicals may be involved in VC dependent mutagenesis.

Aroclors↗
PubMed1998

Identification of amine acceptor protein substrates of transglutaminase in liver extracts: use of 5-(biotinamido) pentylamine as a probe.

Transglutaminase is a calcium-dependent enzyme which catalyzes amine incorporation and cross-linking of proteins. To isolate the amine acceptor protein substrates of transglutaminase in mammalian livers, a biotin-labeled primary amine substrate of transglutaminase, 5-(biotinamido) pentylamine, was used for biotin labeling of proteins in the liver extracts by endogenous transglutaminase activity. The biotin-labeled proteins were isolated and recovered by biotin-avidin-affinity chromatography. The obtained proteins were separated by SDS-PAGE. Proteins with molecular masses of 15, 24, 35, 40, 44, 93, and 134 kDa were the main components of labeled proteins in mouse liver extract. In rat and guinea pig liver extracts, 32-, 38-, 40-, 44-, and 134-kDa proteins and28-, 40-, 44-, 55-, 60-, 91-, and 134-kDa proteins were the main components of labeled proteins, respectively.Using amino-terminal amino acid sequence analyses and sequence homology searches, the 38-kDa protein from rat liver was identified as a subunit of glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.12), and the 28-kDa protein from guinea pig liver was identified as a subunit of glutathione S-transferase (class theta) (EC 2.5.1.18). Both the glyceraldehyde-3-phosphate dehydrogenase from rabbit muscle and glutathione S-transferase (class pi) from human placenta also could be amine acceptors in the amine incorporation catalyzed by guinea pig liver transglutaminase. These results suggest that these enzymes can be modified posttranslationally by cellular transglutaminase.

Amines↗
PubMed1993

Inhibition of glucagon secretion by crude liver extract in conscious dogs.

The feedback regulation between the endocrine gland and its target organ is an expected biological relationship. However, such a phenomenon is not documented between the endocrine pancreas and its major target organ, the liver. Several studies have documented a relationship between hepatic glycogen content and fasting plasma glucagon suggesting that liver may be a modulator of the pancreatic alpha cell function. To further examine this hypothesis, this study determined plasma glucagon, insulin and glucose after an overnight fast and again at frequent intervals up to 60 minutes after an intravenous administration of either crude liver extract or normal saline, 2 ml in 6 conscious dogs. Plasma glucagon and glucose declined significantly following administration of liver extract (p < 0.01), with no alteration in plasma insulin. However, normal saline administration failed to induce changes in any of the parameters studied. Furthermore, integrated responses were significantly larger for glucagon and glucose (p < 0.01), but not for insulin during infusion of the liver extract when compared with normal saline study. Therefore, this study suggests that hepatic tissue may synthesize and secrete a putative factor capable of inhibiting glucagon secretion by the pancreatic alpha cells.

Animals↗
PubMed2005

A deformable model for automatic CT liver extraction.

RATIONALE AND OBJECTIVES: This study was performed to design an automatic liver region extraction system to facilitate clinical liver size estimation and further serve as a prestage for liver reconstruction and volume estimation. MATERIALS AND METHODS: We present a modification of the well-known snakes algorithm for extracting liver regions in noisy CT images. Our modification addresses the issues of selection of the control points on an estimate of the contour and the determination of the weighting coefficients. The weighting coefficients are determined dynamically on the basis of the distance between the control points and the local curvature of the contour. RESULTS: The proposed method was used in extracting liver regions from 98 cross-sectional abdominal images. The overall performance was estimated by comparisons with original liver regions. CONCLUSION: The deformable model method enables an efficient and effective automatic liver region extraction in noisy environments. This approach eliminates human-in-the loop, which is the common practice for the majority of current methods.

Algorithms↗
PubMed1985

The inactivation of ubiquitin accounts for the inability to demonstrate ATP, ubiquitin-dependent proteolysis in liver extracts.

The low molecular weight polypeptide required for energy-dependent proteolysis, ubiquitin, is rapidly inactivated by 100,000 X g supernatants of rabbit liver extracts. Ubiquitin inactivation results from limited proteolysis by an endogenous contaminating lysosomal thiol protease having trypsin-like specificity. Evidence for this includes a pH optimum of 5.0 for the first order constant of ubiquitin inactivation and observation that inactivation is inhibited by EDTA, o-phenanthroline, iodoacetamide, p-chloromercuribenzoic acid, phenylmethylsulfonyl fluoride, N alpha-p-tosyl-L-lysine chloromethyl ketone, leupeptin, soybean trypsin inhibitor, and aprotinin. Metals stimulate but are not required for ubiquitin inactivation with the effect apparently mediated by a low molecular weight heat-labile component of crude extracts. When this heat-labile component is removed by gel exclusion chromatography a number of metals inhibit ubiquitin inactivation. In the presence of excess dithiothreitol, inhibition is relatively specific for Zn(II). Inhibition by Zn(II) is specifically overcome competitively by Cd(II) or by a concentration of ubiquitin in excess of Zn(II). The responsible cathepsin possesses a molecular mass of 35 kDa by gel exclusion chromatography and shows marked thermal lability at neutral pH but stability at acid pH. Proteolytic inactivation of ubiquitin results from limited cleavage of the carboxyl-terminal glycine dipeptide required for isopeptide bond formation and is supported by data on isoelectric point changes on subsequent digestion with carboxypeptidase B and by direct amino acid analysis. When the responsible cathepsin is inactivated, liver extracts display ATP,ubiquitin-dependent proteolysis that cannot be ascribed to contaminating erythrocytes. Thus the previous inability to demonstrate energy-dependent proteolysis in liver extracts is accounted for by the artifactual inactivation of ubiquitin.

Adenosine Triphosphate↗
PubMed1976

The exchange of erythrocyte membrane phospholipids with rat liver extracts in vitro.

Intact rat or human erythrocytes and their isolated (ghost) membranes were incubated with the high speed supernatant fraction of homogenates derived from 32P-labeled rat livers. Phospholipid molecules were transferred between the red cell membranes and the liver extracts, as reflected by the convergence of their specific radioactivities with time. Whereas ghosts usually approached isotopic equilibrium with the liver supernatant fraction during a few hours of incubation at 37 degrees C, the exchange of phospholipids by intact cells was no more than one-half, even after 18 hr. Phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine and sphingomyelin were all exchanged in both intact cells and ghosts, albeit to different extents. (A control experiment, incubating 32P-labeled rat erythrocytes or ghosts with unlabeled rat liver extracts, also demonstrated the exchange of all four major phospholipids.) These data may signify that the phospholipids on the cytoplasmic side of the membrane of intact erythrocytes do not exchange with the phospholipids in exogenous liver extracts. If so, all four major phospholipid classes would appear to be present to some extent at both membrane surfaces. The first inference is in agreement with several other studies on this membrane, while the second inference is not.

Animals↗
PubMed1991

Action of plasma and liver extract from adult mice on the mitotic activity of young mouse liver.

Inbred C3HS male mice, standardized for periodicity analysis were used. A hundred and seventy 25 +/- 2 days old mice were injected at 16:00 hs with saline, plasma or liver extract from 27 mice 90 days old. Controls were made at 08/16, 12/20, 16/24, 08/40, 12/44, 16/48, 08/64, 12/68 and 16/72 (time of day/time post-injection). The mitotic activity of the hepatocytes and litoral cells were determined. The injection of small doses of extract and plasma inhibits the mitotic activity of hepatocytes during the first and second following days. A compensatory wave appears in the third day. The extract inhibits the mitotic activity of litoral cells in the first day of control only, whereas the plasma inhibits this variable in the second and third day.

Animals↗
PubMed1985

Repair of O4-methyldeoxythymidine residues in DNA by mammalian liver extracts.

The enzymatic repair of O4-methyldeoxythymidine (O4-MedT) by mammalian liver extracts was investigated in vitro using double-stranded poly[d(A-T) X d(A-T)] alkylated with N-[methyl-3H]-N-nitrosourea as a substrate. The removal of O4-MedT by monkey liver extracts was proportional to the protein concentration of the reaction mixture up to approximately 4 mg/ml, while kinetic analysis revealed the repair reaction reached a plateau by 2 h at 37 degrees C. The removal of O4-MedT could not be accounted for by contaminating nuclease activity, for greater than 90% of the 3-methyldeoxythymidine (3-MedT) was always recovered, whereas O4-MedT declined to as little as 25% of control values. A DNA-glycoslyase is not involved in the repair of O4-MedT, for O4-methylthymine, the free base, was not detected in supernatants from monkey liver reaction mixtures following incubation with substrate and precipitation of macromolecules with ethanol, even though analysis of nucleic acid digests of these assays revealed O4-MedT was lost from the substrate. The order of O4MedT repair activity in human, monkey, partially hepatectomized rat and methylguanine DNA-methyltransferase activity, with human and monkey most active, partially hepatectomized rat intermediate in activity and control rat least active. Our findings suggest the same, or a similarly regulated mammalian liver DNA-methyltransferase repairs O6-methylguanine and O4-MedT residues in DNA, yet the affinity of the enzyme(s) differs for these promutagenic adducts, as we estimate 30-50 O6-methylguanines would be repaired for every one O4-MedT repaired.

Animals↗