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The resonance Raman spectra of [2-13C]-, [4a-13C]-, [4-13C]-8 [10a-13C]-, [2,4,4a, 10a-13C]-, [5-15N]-, [1,3-15N]-, and [1,3,5-15N]riboflavin bound to egg-white proteins were observed for N(3)-H and N(3)-D forms with spontaneous Raman technique by using the 488.0-nm excitation line of an argon ion laser. The fluorescence of riboflavin was quenched by forming a complex with egg-white riboflavin binding protein. The in-plane displacements of the C(2), C(4a), N(1), N(3), and N(5) atoms during each Raman active vibration were calculated from the observed isotopic frequency shifts. The 1252-cm-1 mode of the N(3)-H form was found to involve large vibrational displacements of the C(2) and N(3) atoms and to be strongly coupled with the N(3)-H bending mode. This line can be used as an indicator for state of N(3)-H...protein interaction. The 1584-cm-1 mode, which is known to be resonance-enhanced upon excitation near the 370-nm absorption band, was accompanied by the displacement of the N(5) atom in particular. The 1355-cm-1 mode was most strongly resonance-enhanced by the 450-nm absorption band and involved the displacements of all carbon atoms of ring III. Both lines can be used as structure probes for elucidating the structure of electronically excited states of isoalloxazine.

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Mammalian muscles synthesize L-carnosine, but its roles were unknown. Previously, we found in rats that the administration of a certain amount of L-carnosine elicited an inhibition of the hyperglycemia induced by the injection of 2-deoxy-D-glucose (2DG) into the lateral cerebral ventricle (LCV), and that intravenous injection of L-carnosine inhibited sympathetic nerves and facilitated the parasympathetic nerve. Moreover, the suppressive effect of L-carnosine on the hyperglycemia induced by 2DG was eliminated by thioperamide, a histaminergic H3 receptor. These findings suggested that L-carnosine might control the blood glucose level through regulating autonomic nerves via H3 receptor. To further clarify the function of L-carnosine, we examined its role in the control of the blood glucose. In this experiment, the following results were observed in rats: (i) A certain amount (0.01% or 0.001%) but not a larger amount (0.1%) of L-carnosine given as a diet suppressed the hyperglycemia induced by LCV-injection of 2DG (2DG-hyperglycemia); (ii) LCV-injection but not the injection into the intraperitoneal space (IP) of a certain amount of L-histidine suppressed the 2DG-hyperglycemia; (iii) treatments of diphenhydramine, an H1 antagonist, and alpha-fluoromethylhistidine, an inhibitor of histamine-synthesizing enzyme, reduced the 2DG-hyperglycemia; (iv) the plasma L-carnosine concentration and carnosinase activity showed daily changes; (v) the plasma L-carnosine concentration was significantly lower in the streptozotocin-diabetic rats; (vi) exercise by a running wheel tended to increase carnosine synthase activity in the gastrocnemius muscle and elevated the plasma L-carnosine concentration in the dark (active) period, and enhanced the plasma carnosinase activity in the light period; (vii) IP-injection of certain amount of L-carnosine stimulated the feeding response to IP-injection of 2DG. These findings suggest a possibility that L-carnosine released from muscles due to exercise functions to reduce the blood glucose level through the regulation of the autonomic nerves.

To exert beneficial effects for the host, for example, improving the intestinal microflora, a probiotic must reach the intestine as a viable strain. These properties must be demonstrated by in vitro as well as in vivo methods. However, only a few well-designed human clinical studies have shown these properties. Lactobacillus johnsonii La1 has been shown to give many beneficial effects for the host, but it is unclear whether a viable strain of L. johnsonii La1 has the effect of improving host intestinal microflora. In the present study, a randomised double-blind placebo-controlled cross-over trial was conducted to elucidate the effect of L. johnsonii La1 on human intestinal microflora. Twenty-two young healthy Japanese women were randomly divided into two groups, and either received fermented milk with L. johnsonii La1 or a fermented milk without L. johnsonii La1 (placebo) daily for 21 d. Consumption of the fermented milk: (a) increased total Bifidobacterium and Lactobacillus, and decreased lecithinase-positive Clostridium in the faeces; (b) increased the faecal lactic acid concentrations; (c) decreased the faecal pH; (d) increased the defecation frequency. These changes were stronger than those observed with the placebo. L. johnsonii La1 was identified in all subjects only after the consumption of the fermented milk. These results suggest that L. johnsonii La1 can contribute to improve intestinal microflora with probiotic properties.

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Probiotics have potential to improve host immunity; however, there is less evidence showing their efficacy against infections and nutritional status in the elderly. We conducted a double-blinded feeding trial in the elderly to elucidate the effect of fermented milk containing Lactobacillus johnsonii La1 (LC1 w ) on infections and nutritional status. Twenty-four completely enterally fed elderly in-patients aged over 70 years were randomly assigned into two groups. All subjects were administered 3768 kJ (900 kcal)/d of total enteral nutrition (EN) through tube feeding for 12 weeks. Subjects in the LC1 group were administered 373 kJ (89 kcal)/d of LC1 fermented milk after feeding of 3395 kJ (811 kcal)/d of EN for 12 weeks. In the control group, 373 kJ/d of the same EN was replaced from the fermented milk. In the LC1 group, the percentage of days with infections during the run-in observation period was 15·4 (SD 17·3) %, which significantly decreased to 5·7 (SD 8·1) % during the intervention period (P¼ 0·018), and the reduction was larger than that of the control group (P¼ 0·047). Blood Hb increased (P, 0·05), and there was a tendency towards an increase in serum albumin and a decrease in TNF-a (a pro-inflammatory cytokine) in the LC1 group. There was a trend towards an increase in blood phagocytic activity (a natural immunity marker) in the subjects whose initial level was low in the LC1 group. There were no changes in those parameters in the control group. Administration of fermented milk containing the probiotic L. johnsonii La1 may contribute to suppressing infections by improving nutritional and immunological status in the elderly.