Modulation of cholestatic factor production by serum components

When lymph node cells from sensitized guinea pigs were stimulated in vitro with a specific antigen and their culture supernatant was injected into the mesenteric vein of rats, a marked decrease in bile flow was demonstrated. The treatment of activated lymphocytes with a higher molecular weight fraction of normal human serum Fr-1 and Fr-2 was shown to decrease the reduction of bile flow. Conversely, a lower molecular weight fraction of serum (Fr-3) was found to augment the reduction of bile flow. These findings suggest that the serum components may regulate the production of a factor (or factors) causing the decrease in bile flow from the activated lymphocytes.

Lipid peroxide formation in isolated hepatocytes by cytotoxic factors produced from lymphokine-activated macrophages

When peripheral blood lymphocytes from patients with chronic active hepatitis were stimulated with liver specific lipoprotein (LSP), considerably higher frequencies of lymphocyte transformation and MIF production were induced. Peritoneal macrophages from guinea pigs were activated by lymphokine-containing lymphocyte culture supernatant and produced a cytotoxic (or cytostatic) factor acting on isolated hepatocytes in culture. The cytotoxic (or cytostatic) factor, which was fractionated by Sephadex G-75 column gel filtration followed by DEAE-cellulose column chromatography, had cytotoxic effect on isolated liver cells and produced a significant amount of lipid peroxide. These results suggested the possibility that the cytotoxic effects may be caused at least partially by the lipid peroxide formation.

Induction of liver cell injury by antibody-dependent monocyte-mediated cytotoxicity in vitro

The isolated liver cells coated with the anti-liver cell membrane antibody were damaged by incubation with the peripheral blood mononuclear cells. This was demonstrated by measuring the reduction of protein synthesis in the target liver cells. Adherent cells from the peripheral blood mononuclear cells were shown to have a sufficient capacity acting on the isolated liver cells as an effector when they were separated from the peripheral blood of normal and patients with acute or chronic active hepatitis. However, those from patients with liver cirrhosis or hepatoma did not show such effector activity in antibody-dependent cell-mediated liver cell damage. These results suggest that possibly antibody-dependent macrophage-mediated cytotoxicity may play some role in the induction of liver cell injury because the anti-hepatocyte membrane antibody is frequently detected in patient's sera, especially in those with chronic active hepatitis.

Cordycepin analogues of 2-5A and its derivatives. Chemical synthesis and biological activity

Cordycepin (3'-deoxyadenosine) analogues of 2-5A were prepared by dicyclohexylcarbodiimide-induced polymerization of cordycepin 5'-monophosphate. A series of oligomers of the general formula p5'(3'dA)-2'[p5'(3'dA)]n (n = 1-5) was obtained. Cordycepin trimer 5'-monophosphate (n = 2) and cordycepin tetramer 5'-monophosphate (n = 3) were converted to the corresponding 5'-di- and triphosphates via the phosphorimidazolide method. Confirmation of assigned structures was provided through enzyme digestions, 1H and 31P NMR, and comparison with material which was synthesized by a completely independent route. Neither the cordycepin trimer triphosphate, ppp5'(3'dA)-2'p5'(3'dA)2'p5'(3'dA), nor the cordycepin tetramer triphosphate, ppp5'(3'dA)2'p5'(3'dA)2'p5'(3'dA)2'p5'-(3'dA), were inhibitors of translation in cell-free extracts of mouse L-cells programmed with encephalomyocarditis virus. In rabbit reticulocyte lysates, the cordycepin trimer triphosphate was devoid of activity, whereas the cordycepin tetramer triphosphate had approximately 1/100th the activity of 2-5A tetramer triphosphate, ppp5'A2'p5'A2'p5'A2'p5'A. Even though the cordycepin analogues were unable to activate the 2-5A-dependent endoribonuclease, they were able to bind to the endonuclease, thereby antagonizing the translational inhibitory effects of 2-5A. Thus, replacement of the 3'-hydroxyl groups of all the ribose moieties of 2-5A results in an analogue which can bind to the 2-5A-dependent endoribonuclease but is incapable of activating the enzyme. The 3'-hydroxyl groups of 2-5A, therefore, are critical for activation of the 2-5A-dependent endonuclease.

Characterization of antibody to 2'-5' linked oligoadenylic acid

Antibody to 2'-5' linked triadenylate, A2'p5'A2'p5'A, was prepared by injecting bovine serum albumin conjugated with A2'p5'A2'p5'A into rabbits. The [8-14C]-A2'p5'A2'p5'A used in the study was synthesized by nonenzymatic template-directed condensation of [8-14C]AMP and 5'-phosphorimidazolide of A2'p5'A on poly U. The specificity of the antibody was determined by the inhibition of the binding of the radioisotope probe to the antibody by a competitor using the ammonium sulfate precipitation method. The cross reactivity of a number of modified oligonucleotides has been evaluated in order to gain information on the structural feature involved in the binding to the antibody. The adenine moiety and 2'-5' internucleotide linkage are crucial regions for the binding. The antibody reacted not only on A2'p5'A2'p5'A and A2'p5'A2'p5'A2'p5'A, but also on a cordycepin analogue of the trimer, (3'dA)2'p5'(3'dA)2'p5'(3'dA), significantly. Considerable cross reaction was observed with oligoadenylates bearing both 2'-5' and 3'-5' internucleotide linkages, while there was little cross reaction with 3'-5' linked oligoadenylates. The antibody showed very low or no affinity for adenosine, adenine mononucleotides, other nucleotides and other 2'-5' linked trinucleotides. The cross reactivity of the modified oligonucleotides is indicated to have relation to the biological activity of the corresponding 5'-phosphorylated oligonucleotides, so far reported. The antibody was further purified by affinity chromatography using RNA-Sepharose and AMP-Sepharose giving high specificity.

[Collagen metabolism of skeletal muscles following injuries of the peripheral nerves]

In order to elucidate the mechanisms of fibrosis and atrophy of skeletal muscles after peripheral nerve injuries, the biochemical changes in collagen from gastrocunemius muscles of adult albino rabbits have been analyzed after denervation of the proximal portion of sciatic nerve. The wet weight of gastrocunemii was found to decrease at the end of the second week after denervation, and the total collagen content in the muscles progressively increased throughout the whole observation period of 12 weeks. In contrast, the amount of connectin, an intracellular elastic protein was found to decrease after denervation. The amounts of total soluble collagen, pepsin-released collagen and the reducible cross-links were remarkably increased with the passage of time after denervation. The total glycosylated hydroxylysine, especially glucosylgalactosylhydroxylysine contents of the collagen were found to decrease after denervation. These findings strongly indicate that the progressive fibrosis of skeletal muscles after peripheral nerve injury may be mostly produced by the enhanced formation of immatured collagen fibers in tissues, rather than the decrease in the amount of structural muscle proteins as discussed before.

Prebiotic peptide-formation in the solid state. II. Reaction of glycine with adenosine 5'-triphosphate and P1,P2-diadenosine-pyrophosphate

When a solution containing gly-N-pa and imidazole is evaporated to dryness and then maintained at a temperature between 65 degrees C and 100 degrees C, high yields of AppA and obligoglycines are obtained. We believe that ImpA is formed first, and then activates the carboxyl group of glycine or gly-A-pA. If glycine, ATP or AppA, and imidazole are heated together in the solid state, ImpA is formed and ATP , or indirectly from imidazole and gly-N-pA. Next the carboxyl group or glycine is activated by the ImpA formed in situ. The subsequent reactions of activated glycine leads to the formation of oligoglycines and the 2' (3')-glycylester of pA. Under plausible prebiobic conditions, good yields of oligoglycines up to the octamer can be obtained from glycine, ATP and imidazole.

Prebiotic peptide-formation in the solid state. III. Condensation reactions of glycine in solid state mixtures containing inorganic polyphosphates

The reactions of glycine with inorganic polyphosphates in the solid state have been studied. The formation of peptides up to the decamer occurs at moderate temperatures(r.t.-100 degrees C) in the presence of imidazole and magnesium chloride. If adenosine 5' -monophosphate is added to the reaction mixture, 2'(3') -o-glycyl adenosine 5'-monophosphate is also obtained. These reactions could have occurred on the primitive earth.

Prebiotic peptide-formation in the solid state. I. Reactions of benzoate ion and glycine with adenosine 5'-phosphorimidazolide

The reactions of benzoate ion and of glycine with adenosine 5-phosphorimidazolide have been investigated. Benzoate reacts first to give the anhydride, benzoyl-adenylate, which, in the presence of excess imidazole, reacts further to give the 2'- and 3'-esters of adenosine 5'-phosphate. Glycine also first attacks the imidazolide to give an anhydride, but this compound may react further either to give 2- and 3'-esters or to form peptides, depending on the reaction conditions.