Effects of butyrate on cell cycle progression and polyploidization of various types of mammalian cells.

We studied the effect of butyrate on cell cycle progression and polyploidization in three fibroblast (rat 3Y1, human IMR-90, and human embryo lung HEL) and two epithelial (human embryo kidney HEK and monkey kidney BSC-1) cells. In these cells, except for 3Y1, G1 arrest with butyrate was incomplete, and the production of tetraploid cells was detectable in the presence of butyrate. G2 arrest with butyrate was also incomplete in HEL and BSC-1 cells, and the number of HEL cells increased in the presence of butyrate. On the contrary, most BSC-1 cells that divided in the presence of butyrate were unstable and the number of attached cells decreased. These results indicate that the effect of butyrate on cell cycle progression varies with the cell type and that polyploidization can be induced by a single treatment with butyrate.     

Effects of bile acids and lectins on immunoglobulin production in rat mesenteric lymph node lymphocytes

Summary We investigated the effect of bile acids either alone or in combination with lectins on immunoglobulin (Ig) production in vitro of rat mesenteric lymph node (MLN) lymphocytes to examine their immunoregulatory activities. Among free bile acids examined, chenodeoxycholic acid stimulated IgE production by MLN lymphocytes and inhibited IgA production at the concentration of 0.3 mM, whereas cholic and deoxycholic acids exerted the comparable effect at 3 mM. Among conjugated bile acids, deoxycholic acid derivatives stimulated IgE production more strongly than cholic acid derivatives. On the other hand, free and conjugated bile acids did not affect IgG production. The IgE production by MLN lymphocytes was stimulated by concanavalin A and inhibited by pokeweed mitogen, and the effect of phytohemmagglutinin and lipopolysaccharide was marginal. These lectins did not affect IgA and IgG production by the lymphocytes. In the presence of lectins, free bile acids affected IgE production at 0.03 mM. These results suggest the possibility that bile acid is a stimulant for food allergy.     

Serum and liver lipid composition and lecithin: cholesterol acyltransferase in horses, Equus caballus.

1. The lipid composition of serum and liver and some properties of serum lecithin: cholesterol acyltransferase of the horse were investigated. 2. Phospholipids and cholesterol were the major components of serum lipids and the concentration of triglyceride was considerably low. The concentration of liver lipids was comparable with that of other mammals. 3. Fatty acid composition of serum cholesterol ester resembled that of the 2-position of lecithin, except palmitic acid. 4. The activity of serum cholesterol esterifying enzyme was found to be 0.03-0.09 mumol/hr per ml. There was an equimolar decrease in free cholesterol and lecithin during incubation, and changes in unsaturated fatty acids in these two components were in good agreement. 5. Cholesterol esterification was reversibly inhibited by 5,5'-dithiobis-(2-nitrobenzoic acid). The acyl-transferase had a specificity for linoleic acid.     

Synthesis and central nervous system actions of thyrotropin-releasing hormone analogs containing a 1-substituted 2-oxoimidazolidine moiety

A series of thyrotropin-releasing hormone (TRH) analogs in which the pyroglutamic acid residue was replaced by (S)-2-oxoimidazolidine-4-carboxylic acid (Oic-OH) and the related derivatives was prepared, and the central nervous system (CNS) actions were examined. Of these, 1-benzyl-Oic-His-Pro-NH2 (2c) showed the most potent activities, which were 1.5-8 times greater than those of TRH. Moreover, the thyrotropin (TSH)-releasing activity of 2c was about 1/16 times weaker than that of TRH.     

Detection of specific antibodies against fimbriae and membrane proteins from the oral anaerobe Bacteroides gingivalis in patients with periodontal diseases

Sera from a number of patients with periodontal diseases were shown to have specific immunoglobulin G (IgG) antibodies against fimbriae and membrane proteins of Bacteroides gingivalis, a suspected pathogen, by using Western blottin analysis. The sera had a strong tendency to react with fimbriae, or exactly oligomeric structures of fimbriae with a native beta-structure rich-conformation. However, the sera did not react with fimbrilin, a constituent protein of fimbriae, which is denatured by sodium dodecyl sulfate.     

Factors in the Fermentation-Inhibition Test for Measurement of Growth-Inhibiting Antibody to Mycoplasma pneumoniae

Factors in the fermentation-inhibition test for the measurement of growth-inhibiting antibody in serum to Mycoplasma pneumoniae were studied. The fermentation-inhibiting antibody titer, as read on the day when the color of the control cup without serum had just changed to yellow, was constant among inoculum dilutions of 10^–2 to 10^–5 (10⁶ to 10³ CFU/ml) of a M. pneumoniae broth culture. The use of 10^–3 to 10^–5 dilutions (10⁵ to 10³ CFU/ml) was adequate for inoculation, inasmuch as one day delay in reading did not result in a significant decrease in the test. Heat inactivation of the serum gave no significant effect on the titer. The test was simple and reliable. The growth-inhibiting antibody was shown to be detectable in the test, when the growth of M. pneumoniae was suppressed at least to 1/100 of the growth of the control without serum. The growth-inhibiting antibody titer rose later than the complement-fixing antibody titer in some cases after M. pneumoniae infection. It is suggested that, when an erythromycin-sensitive strain of M. pneumoniae is used, the titer transiently rises and does not show a real growth-inhibiting antibody titer in sera from patients under erythromycin administration.