Geographic variations in the carbon isotope composition of the human diet and human hair were investigated. The carbon isotopic composition of common foodstuffs purchased in Chicago, USA, Tokyo, Japan and Munich, FRG, were determined by combustion and differential isotope ratio mass spectrometry. The dietary protein carbon for the United States (-18.1%) was calculated to be enriched in 13C relative to the Japanese (-21.2%) and the German (-23.6%) diets. To a large degree, the differences reflected the consumption of corn-fed animal products in the United States and Japan, as well as seafood in Japan. The carbon isotopic composition of hair (-16.4, -18.0 and -20.4%) for the three respective populations correlated with the calculated values of the dietary protein, but were 2-3% enriched in 13C. Changes in the isotopic composition of beard hair were shown to record the changes in dietary composition in travelers visiting the respective regions.

No abstract

Natural differences in 13C/12C ratios of various metabolic fuels can produce systematic changes in the 13C/12C ratio of breath CO2, and therefore introduce errors into 13CO2 breath tests. To gain insight into the potential problem, we compared 13C/12C ratios of plasma macronutrients to those of breath CO2 under conditions that should alter the percentages of carbohydrate and lipid being oxidized. In rats, 48 h of starvation decreased the 13C/12C ratio of breath CO2 by 3.5%. At this time the 13C/12C ratio of breath CO2 was very similar to that of plasma lipids. In humans, 30 min of heavy exercise increased the breath 13CO2/12CO2 ratio by 1.3%. These changes in breath 13C/12C ratios could be predicted from 13C/12C ratios of plasma macronutrients and the percentage of carbon dioxide derived from each macronutrient, but only when compared within the same populations. For example, the 13C/12C ratios of plasma macronutrients of residents of Chicago, Illinois (USA) and Tokyo (Japan) differed by 1-3%. An empirical correction of 13CO2 breath test data is recommended when breath tests are run under conditions that will change metabolic fuel utilization.

SummaryTo elucidate the effect of ␥ -aminobutyric acid (GABA) on both psychological and physical fatigue and on the performance advances for task solving, we assigned an arithmetic task for the Uchida-Kraepelin Psychodiagnostic Test (UKT) to 30 healthy Japanese subjects, 9 of whom were diagnosed as having chronic fatigue. The subjects were administered 250 mL of a test beverage containing GABA at the dose of 0, 25, and 50 mg before assigning task for the UKT. Psychological fatigue assessed by the Visual Analogue Scale (VAS) was significantly lower in the group administrated the beverage containing 50 mg GABA than in the control group ( p Ͻ 0.05). The results of the Profile of Mood States (POMS) also indicated that psychological fatigue was significantly reduced in the 50-mg-GABA group. The salivary secretion levels of chromogranin A and cortisol-markers of physical fatigue-in both 25-mg and 50-mg-GABA groups were significantly lower than those in the control group. The 50-mg-GABA group also showed higher score on UKT by solving the arithmetic task more accurately than the control group ( p Ͻ 0.01). The results suggest that intake of GABA-containing beverages, especially those containing 50 mg of GABA, may help reduce both psychological and physical fatigue and improve task-solving ability.

As part of our studies of selectin blockers, we prepared 1-deoxy-3'-O-sulfo LeX analogs (1-3), 1-deoxy-3'-O-phosphono LeX analogs (4), and 1-deoxy sLeX analogs (5-7), and examined their inhibitory activities against natural ligand (sLeX) binding to E-selectin, P-selectin, and L-selectin. The 1-deoxy sLeX 5 was up to 20 times more potent an inhibitor than the sLeX tetrasaccharide toward P- and L-selectin binding. This indicates that the modification of the 1 or 2 position of sLeX is useful in the design of a more potent selectin blocker.

No abstract

The reactions of newly prepared fac(S)-[IrIII(aet)3] or ΔLLL-fac(S)-[IrIII(l-cys-N,S)3]3− with Co2+, followed by the air or H2O2 oxidation, gave linear-type S-bridged trinuclear complexes, [CoIII{IrIII(aet)3}2]3+ and ΔLLLΔLLL-[CoIII{IrIII(l-cys-N,S)3}2]3−. The aet trinuclear complex was separated and optically resolved into the ΔΛ, ΔΔ, and ΛΛ isomers and the crystal structure of the ΔΛ isomer was determined by X-ray diffraction. [Co{Ir(aet)3}2](NO3)3·2H2O, chemical formula C12H40N9S6O11CoIr2, crystallizes in the triclinic, space group with a = 8.945(2), b = 12.073(3), c = 8.849(3) Å, α = 110.36(2), β = 102.55(2), γ = 70.88(2)°, U = 841(2) Å3, Z = 1, and R = 0.059. The central Co(III) has a trigonally distorted octahedral geometry, coordinated by six thiolato sulfur atoms from the octahedral Δ- and Λ-fac(S)-[Ir(aet)3] terminals. The other trinuclear complexes were characterized by their absorption, CD, and 13C NMR spectra. The meso–racemic isomerization, which results from the cleavage of the Co–S bonds, was recognized for [Co{Ir(aet)3}2]3+ in D2O, methanol–H2O, and ethanol–H2O. The cyclic voltammogram of rac-[Co{Ir(aet)3}2]3+ in water showed two almost reversible redox couples at −0.23 V and +0.73 V (vs. Ag/AgCl). The chemical properties of the present IrIIICoIIIIrIII complexes are discussed in comparison with those of the corresponding RhIIICoIIIRhIII and CoIIICoIIICoIII complexes.

Sensitive and specific methods for the simultaneous determination of gemfibrozil (Lopid), a lipid-lowering agent, and its metabolites in plasma and urine are described. The methods are based on a fully automated high performance liquid chromatographic (HPLC) system with fluorescence detection. Urine samples, diluted with acetonitrile, were directly analysed by HPLC using a flow and eluent programming method. In the case of plasma, gemfibrozil and its main metabolites were extracted from acidified samples and the resulting extracts injected into the chromatographic system. The sensitivity was approximately 100 ng/mL for gemfibrozil and its four metabolites using 0.5 mL plasma or urine. An acyl glucuronide of gemfibrozil excreted in human urine after oral administration of the drug was isolated and its structure and stability examined.