Inhibition of benzoyl peroxide/Cu2+-dependent lipid peroxidation by manganese

1. Formation of peroxides by benxoyl peroxide (BPO) and CuCl2 was examined in the human red blood cell ghost. 2. Amounts of peroxides formed increased with the amount of the ghost solution added. 3. Of all the cations tested only manganese ion inhibited the formation of peroxides in BPO-CuCl2 reaction system. 4. The formation of peroxides was inhibited approx. 50% with 0.4 microM manganese. 5. The inhibitory manner of manganese was non-competitive against copper.     

Effects of Hydrostatic Pressure on Carcinogenic Properties of Epithelia

The relationship between chronic inflammation and cancer is well known. The inflammation increases the permeability of blood vessels and consequently elevates pressure in the interstitial tissues. However, there have been only a few reports on the effects of hydrostatic pressure on cultured cells, and the relationship between elevated hydrostatic pressure and cell properties related to malignant tumors is less well understood. Therefore, we investigated the effects of hydrostatic pressure on the cultured epithelial cells seeded on permeable filters. Surprisingly, hydrostatic pressure from basal to apical side induced epithelial stratification in Madin-Darby canine kidney (MDCK) I and Caco-2 cells, and cavities with microvilli and tight junctions around their surfaces were formed within the multi-layered epithelia. The hydrostatic pressure gradient also promoted cell proliferation, suppressed cell apoptosis, and increased transepithelial ion permeability. The inhibition of protein kinase A (PKA) promoted epithelial stratification by the hydrostatic pressure whereas the activation of PKA led to suppressed epithelial stratification. These results indicate the role of the hydrostatic pressure gradient in the regulation of various epithelial cell functions. The findings in this study may provide clues for the development of a novel strategy for the treatment of the carcinoma.     

Meal feeding schedule and ventromedial hypothalamic lesions do not affect rhythm of pineal serotonin N-acetyltransferase activity in rats

Effects of meal feeding schedule and bilateral lesions of the ventromedial hypothalamus (VMH) on the circadian rhythm of pineal serotonin N-acetyltransferase (SNAT) activity were examined in rats, under LD (12:12) condition. Neither meal feeding nor VMH lesions affected the phase of the circadian rhythm of pineal SNAT activity, but the VMH lesions reduced the level. Meal feeding caused a shift of the phases of the daily rhythms of phosphoenolpyruvate carboxykinase and tyrosine aminotransferase activities in the liver. These findings suggest that the circadian rhythm of pineal SNAT activity is not entrained by the food intake, and that the VMH does not function as a master oscillator of the rhythm.     

Identification of (Na,K)ATPase inhibitor in brine shrimp,Artemia salina,as long-chain fatty acids

Summary An inhibitory activity to (Na,K)ATPase was found in cell extracts of the brine shrimp, Artemia salina, irrespective of its developmental stages. Organic solvent extraction together with gas chromatographic analysis reveals that the inhibitory activity is due to long-chain, non-esterified fatty acids and their derivatives. Unsaturated fatty acids, especially with cis-configuration, are more effective in inhibition than saturated ones.Abbreviations ATPase adenosine triphosphatase - EDTA ethylenediamine-tetraacetate - TLC thin-layer chromatography     

Altered localization of antigen recognized by proteinuriainducing monoclonal antibody in experimental nephrosis

Change in the localization of the antigen recognized by the proteinuria-inducing monoclonal antibody (MA) 5-1-6 in experimental nephrosis was studied by indirect and biotin-avidin immunofluorescence, and immunoperoxidase at light and electron microscopical levels. The proteinuric state was induced by the administration of the aminonucleoside of puromycin (PAN) or adriamycin. The antigen decreased in quantity and/or its distribution changed with an increase in the amount of protein excreted in both experimental models. Recovery from the alterations observed during the development and proteinuria appeared to occur when PAN-induced proteinuria subsided. This antigenic molecule may thus be essential for maintaining the normal permselectivity of glomerular capillary walls.     

Spontaneous malignant lymphoma in an African green monkey naturally infected with simian T-lymphotropic virus (STLV)

An African green monkey naturally infected with simian T-lymphotropic virus (STLV) developed spontaneous malignant lymphoma of diffuse pleomorphic type. The clinical, hematological and histopathological characteristics were very similar to those of human adult T-cell leukemia.     

Expression in Escherichia coli of chemically synthesized gene for the human immune interferon.

A 454 base pair fragment of double stranded DNA consisting of a gene for a human immune interferon (hIFN-gamma), initiation and termination signals plus appropriate restriction endonuclease sites, was totally synthesized. The synthesis involved preparation of 62 oligodeoxyribonucleotides by rapid, solid phase procedures, and enzymatic ligation of the oligonucleotides. This synthetic gene was expressed in E. coli under the control of the lac UV5 promoter. The product has antiviral activity which was acid labile and completely neutralized by antiserum to hIFN-gamma but not by antiserum to hIFN-alpha or hIFN-beta. Molecular weight of hIFN-gamma produced by E. coli was estimated to be about 32,000 and 17,000 by gel filtration and SDS-polyacrylamide gel electrophoresis respectively.     

Identification of membrane anchoring site of human renal dipeptidase and construction and expression of a cDNA for its secretory form

The chemical properties of human renal dipeptidase (hrDP) purified from the membrane fraction of kidney have been characterized. When treated with phosphatidylinositol-specific phospholipase C, hrDP was released from renal membrane fractions. After digestion with trypsin, carboxyl-terminal peptide was isolated employing anhydrotrypsin-agarose column chromatography and reversed-phase high performance liquid chromatography. The amino acid sequence of the peptide was identified at positions 363-369 in the primary structure deduced from the cDNA sequence (Adachi, H., Tawaragi, Y., Inuzuka, C., Kubota, I., Tsujimoto, M., Nishihara, T., And Nakazato, H. (1990) J. Biol. Chem. 265, 3992-3995). Further examination of the chemical composion of the peptide showed that it contained, respectively, 2, 1, 5, 1, and 1 mol of ethanolamine, glucosamine, mannose, inositol, and phosphate in addition to amino acids. These results suggest that the mature hrDP molecule lacks the carboxyl-terminal hydrophobic peptide extension predicted from the cDNA sequence and is anchored at Ser369 via glycosylphosphatidylinositol to the membrane. To characterize further the action of the enzyme, we have established expression systems for both secretory and membrane anchored forms of hrDP using COS-1 cells and found that both recombinant forms were as active as natural enzyme. Our expression system made it possible to prepare large amounts of soluble enzyme, and will contribute toward elucidation of the physiological roles of the enzyme.