Using the placental form of glutathione S-transferase (GST-P) as a marker of carcinogen-initiated hepatocytes, we investigated how a choline-deficient (CD) diet and BR931, a carcinogenic hypolipidemic agent, modify populations of single GST-P-positive hepatocytes. The liver of male Fischer rats (6-7 weeks old) fed a CS or basal diet contained mostly single or double GST-P-positive hepatocytes. Feeding a CD diet for 2-4 weeks led to increases in the number of aggregates of two and three GST-P-positive hepatocytes. By 8-12 weeks, there was an emergence of discrete foci of GST-P-positive hepatocytes consisting of more than 20 hepatocytes. Feeding a BR931 diet for 4-8 weeks resulted in no significant change in the number of single GST-P-positive hepatocytes in the liver as compared to feeding a basal diet. It is suggested that single GST-P-positive hepatocytes in the liver of relatively young rats maintained on a commercial diet may represent endogenously initiated cells. A CD diet promotes endogenously initiated cells to form larger aggregates or foci of GST-P-positive cells.
The O-specific polysaccharide from the lipopolysaccharide of Pseudomonas aeruginosa NCTC 8505 (IATS serotype O:3) consists of a tetrasaccharide repeating unit comprising L-rhamnose, N-acetyl-D-glucosamine (GlcNAc), bacillosamine, and N-acetyl-L-galactosaminuronic acid (L-GalNAcA) (Y. Tahara and S. G. Wilkinson, Eur. J. Biochem. 134:299-304, 1983). Incubation of GlcN or UDP-GlcNAc with cell extracts or EDTA-treated cells of P. aeruginosa NCTC 8505 yielded a mixture of UDP-ManNAc, UDP-GalNAc, UDP-GlcNAcA, UDP-ManNAcA, UDP-L-GalNAc, and UDP-L-GalNAcA. The last two compounds, here identified for the first time, may be intermediates in the synthesis of the L-GalNAcA moiety of the O-specific portion of the lipopolysaccharide of P. aeruginosa.
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