The sex difference in the regulation of liver regeneration after partial hepatectomy in the rat

The increases in the activity of hepatic thymidylate synthetase and thymidine kinase, which catalyzes the formation of thymidylate via the de novo and salvage pathways, respectively, were significantly suppressed 24 h after 70% partial hepatectomy in female rats administered either alpha- or beta-adrenoreceptor antagonists. The injection of beta-antagonist to male or ovariectomized female rats had no effect on the activities of these enzymes. Only alpha-adrenoceptor antagonist depressed these enzymatic activities of 24-h-regenerating liver in male and ovariectomized female rats. The decrease of the activities of thymidylate synthetase and thymidine kinase was accompanied by a concomitant reduction of DNA content in 24-h-regenerating liver. It is concluded that catecholamine regulates the female rat liver regeneration through both alpha- and beta-adrenergic pathways by the inductions of thymidylate synthase and thymidine kinase, while in adult male and ovariectomized female rats, only the alpha-mediated pathway is involved.     

Macrophage production of fibronectin, a chemoattractant for fibroblasts

Activation of macrophages results in the production of numerous enzymes and effector molecules. One of these monokines released by macrophages can cause directed migration of connective tissue fibroblasts in vitro. Production of this macrophage-derived chemotactic factor for fibroblasts requires activation of the macrophages either in vivo or in vitro and de novo protein synthesis. The chemotactic activity in the macrophage supernatants could be removed by a fibronectin-specific affinity column and was inhibited in the presence of antibodies to fibronectin. Furthermore, chemotactic activity in the depleted macrophage supernatants could be restored by the addition of exogenous fibronectin. Fibronectin was identified in activated macrophage supernatants by an enzyme-linked immunoassay for fibronectin. From these findings it was concluded that activated macrophages release a chemoattractant for fibroblasts and that the primary chemoattractant molecule is fibronectin. The production of fibronectin by activated macrophages may thus serve as an inflammatory mediator that in addition to its other functions can recruit fibroblasts to an area of damaged tissue, where they can proliferate and form the scar tissue necessary for tissue repair. Furthermore, in chronic inflammation, the prolonged activation of macrophages may be related to the extensive fibroblast infiltration and fibrosis that can accompany these lesions.     

1,N6-Etheno-2-aza-adenosine 3', 5'-cyclic phosphate: human erythrocyte membrane binding and activation of membrane protein kinase.

The relative efficiency of 1,N6-etheno-2aza-adenosine 3', 5'-monophosphate (cyclic 2-aza-epsilon AMP), 1,N6-etenoadenosine 3', 5'-monophosphate (cyclic epsilon AMP) and cyclic AMP in activation of membrane protein kinase and binding to membrane was examined using isolated membranes from human erythrocytes. Cyclic 2-aza-epsilon AMP was 81% as active as cyclic AMP in erythrocyte membrane binding and activation of membrane protein kinase. On the other hand, cyclic epsilon AMP was 37% as active toward membrane protein kinase and 29% toward membrane cyclic AMP binding. Since we have previously shown that the fluorescence of cyclic 2-aza-epsilon AMP is highly sensitive to the polarity of solvents, the high efficiency of cyclic 2-aza-epsilon AMP to substitute for cyclic amp suggests that it may be a suitable microenvironmental fluorescent probe for cyclic AMP binding sites.     

Corelike structures in a stable L-form ofStreptococcus pyogenes

Corelike structures, which were interpreted as straight, large cylinders containing ribosome-like particles surrounded by an amorphous substance of low electron density, were found in a stable L-form ofStreptococcus pyogenes grown in the absence of antibiotics.     

Plant growth-regulating activities of batatasin III analogues

Nine bibenzyls and 10 stilbenes were synthesized as analoguesof batatasin III, a growth inhibitor isolated from dormant yambulbils, and examined for their plant growth-regulating activities.The bioassays used were the elongation of dark-grown intactrice coleoptiles, auxin-induced elongation of excised oat coleoptiles,and germination of rape and barnyard grass seeds. In the elongationof intact rice coleoptiles, 3,3'-dihydroxy-5-methoxy- (batatasinIII), 3,5-dimethoxy-3'-nitro-, 4'-bromo-3-nitro-, 3-amino-3'-chloro-,3-amino-4'-chloro-bibenzyls and 3-benzyloxy-4'-bromo-5-methoxy-,3-benzyloxy-3',4'-dichloro-5-methoxy-stilbenes were inhibitory,and 4'-bromo-3-nitrostilbene was promotive at a concentrationof 100 mg/liter. The results obtained by the other bioassayswere qualitatively consistent with these findings, although3-amino-4'- chlorobibenzyl and 4'-bromo-3-nitrostilbene werenot tested in all the bioassays. In the seed germination, which was rather tolerant to the testanalogues, batatasin III was inactive but 3-benzyloxy-4'-bromo-5-methoxy-and 3-benzyloxy-3',4'-dichloro- 5-methoxystilbenes were veryactive. Thus, if substituted properly, bibenzyls and stilbenes are activewithout hydroxyl and methoxyl group(s) as the functional group. ³ Present address: The National Institute for EnvironmentalStudies, Yatabc, Ibaraki 300-21, Japan. (Received November 19, 1975; )     

Nucleic acid of flacherie viruses of the silkworm, Bombyx mori

It was reported previously that two spherical flacherie viruses of silkworm, FVS I and FVS II, had been isolated from flacherie silkworm larvae and the nucleic acid of FVS II was RNA as suggested by the experiments of incorporation of [³H]-uracil. In this paper, it has been confirmed by biochemical methods that the nucleic acid of FVS I and FVS II is RNA. FVS I and FVS II were labeled with ³²P in flacherie silkworms, and the viruses were analyzed by sucrose density gradient centrifugation. When the ³²P-labeled compound in the viruses was treated with 0.5 n KOH, the acid-insoluble ³²P-labeled compound changed to acid-soluble compounds. It was determined by paper chromatography and ion-exchange column chromatography that the alkali-decomposed compounds included four ribonucleotides. Therefore, the viral nucleic acid of FVS I and FVS II was determined to be RNA. The correlations between FVS I and FVS II particles were discussed, and it was suggested that FVS I and FVS II might be closely related or were the same viral species.     

Kinetic study of alpha-chymotrypsin catalysis with regard to the interaction between the specificity-determining site and the aromatic side chain of substrates.

In order to investigate how changes in the structures of side-chain aromatic groups of specific substrates influence binding and kinetic specificity in alpha chymotrypsin [EC 3.4.21.1]-catalyzed reactions, a number of nucleus-substituted derivatives of the specific ester substrates were prepared and steady-state kinetic studies were carried out at pH 6.5 and 7.8. Ac-Trp(NCps)-OMe was hydrolyzed more readily at low substrate concentration than Ac-Trp-OMe due to its smaller Km(app) value, suggesting that the bulky 2-nitro-4-carboxyphenylsulfenyl moiety interacts with outer residues rather than with those in the hydrophobic pocket and that this interaction increases the binding specificity. Inhibition experiments using the corresponding carboxylate and analogous inhibitors, however, showed that the carboxy group at the para position of the phenyl nucleus of the substituent sterically hinders association with the active site of alpha-chymotrypsin at pH 7.8 but not at pH 6.5. The kcat values of Ac-Trp(CHO)-0Me, Ac-Tyr(3-NO2)-OMe, and Ac-m-Tyr-OMe were much higher than those of the corresponding specific substrates, indicating that derivatives with a substitute as large as a formyl, nitro or hydroxyl group at the xi-position are stereochemically favorable to the catalytic process. Remarkable increases in Km(app) were also observed. The individual parameters for Ac-Dopa-OMe, however, were comparable to those for Ac-Tyr-OMe.     

Simple derivation of the function of genetic information and correction of the proof

The problem of predicting time to extinction in stochastics population models is approached in two ways. First, a finite Markov chain approximation is used to give the distribution of time to extinction and shown to predict simulation results accurately. Second, an approximate numerical integration technique is found to give good relative predictions of persistence using much less computer time. The relevance of the two approaches to real problems is discussed.     

Induced pluripotent stem cell‐derived myeloid cells expressing OX40 ligand amplify antigen‐specific T cells in advanced melanoma

Immune checkpoint inhibitors improved the survival rate of patients with unresectable melanoma. However, some patients do not respond, and variable immune‐related adverse events have been reported. Therefore, more effective and antigen‐specific immune therapies are urgently needed. We previously reported the efficacy of an immune cell therapy with immortalized myeloid cells derived from induced pluripotent stem cells (iPS‐ML). In this study, we generated OX40L‐overexpressing iPS‐ML (iPS‐ML‐Zsgreen‐OX40L) and investigated their characteristics and in vivo efficacy against mouse melanoma. We found that iPS‐ML‐Zsgreen‐OX40L suppressed the progression of B16‐BL6 melanoma, and prolonged survival of mice with ovalbumin (OVA)‐expressing B16 melanoma (MO4). The number of antigen‐specific CD8⁺ T cells was higher in spleen cells treated with OVA peptide‐pulsed iPS‐ML‐Zsgreen‐OX40L than in those without OX40L. The OVA peptide‐pulsed iPS‐ML‐Zsgreen‐OX40L significantly increased the number of tumor‐infiltrating T lymphocytes (TILs) in MO4 tumor. Flow cytometry showed decreased regulatory T cells but increased effector and effector memory T cells among the TILs. Although we plan to use allogeneic iPS‐ML in the clinical applications, iPS‐ML showed the tumorgenicity in the syngeneic mice model. Incorporating the suicide gene is necessary to ensure the safety in the future study. Collectively, these results indicate that iPS‐ML‐Zsgreen‐OX40L therapy might be a new method for antigen‐specific cancer immunotherapy.