Yoshihiro Yamamoto

Antitumor effect of heat-killed Lactobacillus plantarum L-137 through restoration of impaired interleukin-12 production in tumor-bearing mice

Abstractu2002We have previously reported that heat-killed Lactobacillus plantarum L-137 is a potent inducer of interleukin-12 (IL-12) inu2009vivo as well as inu2009vitro in mice. In order to develop effective usage of L. plantarum L-137 for tumor immunotherapy, we examined its antitumor effect against DBA/2 mice inoculated with syngenic P388D1 tumor cells in different treatment schedules. Daily injection of L. plantarum L-137 from the day of tumor inoculation induced a steep increase in plasma IL-12 only after the first injection but not after subsequent injections, and had no effect on tumor growth and survival time. In contrast, daily injection of L. plantarum L-137 from the 7th day after tumor inoculation exerted a marked antitumor effect but such an effect was not evident in mice treated with L. plantarum L-137 twice a week from the 7th day. IL-12 production was considerably impaired at the first injection but steeply increased after the third injection in the mice injected daily with L. plantarum L-137 from the 7th day. Our results suggest that daily administration of L. plantarum L-137 is required to exert an antitumor effect at the late stages of tumor development when IL-12 production is considerably impaired.

Nigerooligosaccharides augments natural killer activity of hepatic mononuclear cells in mice

Nigerooligosaccharides (NOS), a mixture of nigerose and nigerosylmaltooligosaccharides, is immunopotentiating oligosaccharides found in foodstuffs. Augmentation of natural killer (NK) activity by NOS was studied in vitro and in vivo in mice. In vitro treatment of hepatic mononuclear cells (MNC) from normal mice with 1 micro/ml NOS 17 h or just prior to the cytotoxicity assay enhanced their cytotoxicity against YAC-1 cells. NK activity of hepatic MNC was also enhanced in mice injected intraperitoneally with 0.4 mg NOS or in mice given 1% NOS solution orally as a drinking fluid. In association with the augmentation of NK activity, increase in the liver weight induced by intravenous inoculation of EL-4 tumor cells was significantly suppressed by intraperitoneal pretreatment with 0.4 mg NOS. Moreover, drinking 1% NOS significantly improved the survival curve of mice intravenously inoculated with EL-4 cells. Our results suggest that the immunopotentiating activity of NOS is exerted partly through the augmentation of NK activity.

Effects of Intake of a Mixture of Thiamin, Arginine, Caffeine, and Citric Acid on Adiposity in Healthy Subjects with High Percent Body Fat

We assessed the effects of intake of thiamin, arginine, caffeine, and citric acid (TACC) on lipid metabolism in healthy subjects. Thirty-one subjects with high percent body fat (≥25.0%) were randomly assigned to a 12-wk intervention with daily intake of TACC-supplemented tea (1.1, 1240, 52, and 540 mg, respectively; n=16) or control tea (n=15). The percent body fat decreased significantly during the intervention in both groups, especially in the TACC group. A percentage decrease in triceps skinfold was significantly greater in the TACC group than in the control group. The decrease in abdominal visceral fat in obese subjects was significantly greater in the TACC group than in the control group. Serum triglyceride was significantly lower during intervention than that during the non-intervention period in the TACC group. These results suggest that TACC may be effective in reducing body fat in obese subjects.

Nigerooligosaccharides augments mitogen-induced proliferation and suppresses activation-induced apoptosis of human peripheral blood mononuclear cells.

Nigerooligosaccharides (NOS), a mixture of nigerose and nigerosylmaltooligosaccharides, consists of immunopotentiating oligosaccharides found in foodstuffs. We have previously reported that activation of peripheral blood mononuclear cells (PBMC) in response to concanavalin A (Con A) or a streptococcal preparation of OK‐432 is augmented in healthy young adults and elderly subjects after the intake of NOS‐supplemented syrup. A reappraisal of the data suggests that NOS augments proliferation but partly suppresses activation‐induced apoptosis of PBMC in response to these mitogens. To confirm this hypothesis, PBMC from healthy male subjects were stimulated with Con A or OK‐432 in the presence of nigerose at the concentrations at which it was detected in the blood of subjects who had ingested NOS‐supplemented syrup. Cellular activation, specifically metabolic demand, viability and proliferation, was assessed from glucose consumption, by WST‐1 colorimetry and by 5‐bromo‐2′‐deoxy‐uridine incorporation assay, respectively. The Con A‐induced activation of PBMC in each measurement was significantly augmented by nigerose. OK‐432‐induced decreases in the viability of PBMC were significantly inhibited by nigerose. Stimulation of PBMC with Con A or OK‐432 induced apoptosis, but nigerose suppressed such activation‐induced cell death. These results indicated that nigerose activated PBMC in vitro in a manner similar to the process observed in vivo, providing further evidence for the effectiveness of consumption of NOS‐supplemented syrup.

Fatty acid analysis of triacylglycerols: Preparation of fatty acid methyl esters for gas chromatography

A method to prepare fatty acid methyl esters was developed for fatty acid analysis of triacylglycerols by gas chromatography (GC). Triacylglycerols were mixed with methanolic CH3ONa in hexane containing a mid-polar solvent for 10xa0s at room temperature. Under these conditions, trioleoylglycerol was converted to methyl oleate with an average yield of 99.3%. This procedure gave reliable and reproducible data on fatty acid compositions determined by GC.