A macroglycolipid containing galactose and N-acetylglucosamine as predominant sugar constituents was prepared together with glycophorin from rabbit erythrocyte membranes by extraction with lithium diiodosalicylate and partition in aqueous phenol. The macroglycolipid was effectively separated from the glycophorin fraction by ion-exchange chromatography in the presence of a detergent, Ammonyx LO. Its yield (ca. 4 mg/100 ml erythrocytes) was significantly higher than that of the macroglycolipids from human erythrocytes. The structure of the carbohydrate moiety in the macroglycolipid was analyzed by methylation analysis, Smith degradation, nitrous acid deamination, and chromium trioxide oxidation. Assuming one ceramide residue per molecule, the average number of sugars in the macroglycolipid was about 30. The macroglycolipid had a highly branching structure: Gal(alpha 1 leads to 3)Gal(beta 1 leads to 4)GlcNAc sequences are present at nonreducing termini and leads to 3 Gal(beta 1-4)GlcNAc repeating units are present in the inner core of the sugar chain. Some of the inner galactose residues branch at the C-6 position. Constituents of the ceramide moiety were also characterized.

Apoptotic cell death was induced in human lung cancer DMS114 cells by treatment with beta-hydroxyisovalerylshikonin (beta-HIVS), an ATP-noncompetitive inhibitor of protein tyrosine kinases. Changes in phosphoprotein profiles were analyzed by two-dimensional-polyacrylamide gel electrophoresis (2D-PAGE) after the cells were treated with beta-HIVS. One spot on the 2D gel showed a marked decrease in intensity and the corresponding protein was identified by mass spectrometry as dUTP nucleotidohydrolase (dUTPase). The beta-HIVS-induced decrease of dUTPase in the phosphoprotein fraction of DMS114 cells was confirmed using immunoblotting. Treatment of the cells with beta-HIVS-induced rapid reduction of dUTPase activity. An antioxidant N-acetyl-cysteine inhibited both the reduction of phosphorylated dUTPase and the induction of apoptosis by beta-HIVS treatment of DMS114 cells. Introduction of siRNA directed against dUTPase mRNA into DMS114 cells enhanced the susceptibility of beta-HIVS-induced apoptosis. Treatment of DMS114 cells with beta-HIVS and 5-fluorouracil, a specific inhibitor of thymidylate synthase used as a chemotherapeutic drug, revealed the synergistic effects of these drugs on the inhibition of cell growth. These results suggest that dUTPase activity is one of the crucial factors involved in apoptotic cell death in lung cancer cells.

This report presents the ultrastructural features of a congenital epulis. The granular cells of the epulis were packed with numerous membrane bound cytoplasmic granules containing particles, small vesicles, and electron-dense materials. These granules were negative in immunohistochemical reaction for CEA (DAKO PAP KIT). Cytoplasmic organelles such as mitochondria, rough surfaced endoplasmic reticulum, and Golgi apparatus, were absent. Nuclei were markedly indented. Occasionally, banded intracellular collagen fibrils were observed within the cytoplasm. Some of these fibrils were surrounded by a limiting membrane, whereas others appeared to lie free in the cytoplasm. The collagen fibrils were also seen within a deep invagination of the cell surface. There was no basal lamina around the granular cells. Sporadically, mast cells with many granules containing lamellar formations were found between the granular cells. These observations support the idea that granular cells of the congenital epulis are derived from mesenchymal cells, probably fibroblasts.

No abstract

In order to examine whether cytotoxicity test is available as bioassay of water micropollutants, cytotoxicities of 40 chemicals, which have been reported to occur in drinking water, were investigated using 3 different types of cultured cells including HL-60 cells, mouse peritoneal macrophages and rat liver hepatocytes, and the results were compared with their mutagenicity and carcinogenicity. Cancer promotion activity was assayed by use of morphological change of HL-60 cells. Lethality of chemicals was measured with trypan-blue exclusion test of HL-60 cells or lactose dehydrogenase released from rat hepatocytes. Influence of chemicals on cell functions was examined with phagocytic activity of macrophages and glycogenolytic activity of hepatocytes. Some of the chemicals showed strong cytotoxicities which depended on the structure of chemicals and the nature of cells, while cancer promotion activity was not found in any sample. Among the 3 tests, viability test using HL-60 cells was the most susceptible to the chemicals. No correlation was observed between the results of cytotoxicities and their mutagenicity. The results indicate that the combination of some cytotoxicity tests should become effective both to estimate the safety of drinking water and to identify the hazardous micropollutants.