An α-amylase inhibitor from kidney bean (Phaseolus vulgaris cultivar Tora) was separated into two isomers by chromatofocusing. The pI values were 4.70 for the main inhibitor (TAI-I) and 4.60 for the minor inhibitor (TAI-II). TAI-I and TAI-II, which had the same molecular weight of 40, 000, contained carbohydrates of 9.4 and 8.9%, respectively. Amino acid analyses of both inhibitors gave high contents of Asx, Ser, Val, Thr and Glx, although there was little difference in the amino acid composition between the two inhibitors. These inhibitors showed similar inhibitory activities against pancreatic and salivary α-amylases. However, the time required to achieve maximum inhibition of pancreatic α-amylase for TAI-II was less than that for TAI-I. Both inhibitors had similar thermal stability, the inhibitory activity being reduced by about 40% after 20 min of heating at 80°C.

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It is reported that the greater part of Staphylococcus aureus isolated in hospitals is methicillin-resistant Staphylococcus aureus (MRSA) carrying penicillin-binding protein (PBP) 2' and showing high resistance to methicillin. We attempted to isolate MRSA from air in the street, station, train, etc. to estimate the frequency of emergence and the degree of resistance of MRSA in an urban living environment. Among the 988 strains growing on a mannitol/NaCl medium, which is selective for staphylococcal bacteria, 39 strains grew on the medium containing 16 μg/ml of methicillin and were Gram-positive cocci and positive in the coagulase test. Five strains were S. aureus and 21 strains were other staphylococcus species. They did not have PBP 2' and were borderline resistant against methicillin. This result indicates that there are few highly resistant MRSA strains in the air of an urban environment such as in streets, stations or inside trains, which is different from the case in hospitals.

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Bed climate and the subjective sleep quality of the aged in two different nursing homes (NH) were surveyed. Thirty aged volunteers were selected from nursing homes in central Tokyo (T) and in a suburb of Nagano (N). They were divided into four groups depending on their NH and Activity of Daily Living (ADL). The four groups were : subjects with almost no problems in daily life with a high ADL score [T-high, N-high] and subjects who normally stayed in bed all day with a low ADL score [T-low, N-low]. The temperature and humidity of the bedroom and bed climate, the circadian rhythm of subjective sleepiness, vitality and overall feeling, and subjective sleep quality were surveyed. The bedroom temperature was lower and the humidity was higher in the N-high and N-low compared to the T-high and T-low. The bed climate in the daytime was significantly lower in the T-high compared to the other groups. The bed climate at night did not show any significant difference among the groups which were maintained at 32-34°C and 50-60% RH. The daytime sleepiness was lowest in the T-high compared to the other groups and that of the T-low tended to be lower than in the N-low. The subjective sleep quality was significantly higher in the T-high and T-low compared to the N-high and N-low. These results suggest that subjective sleep quality may differ depending on the nursing home and it has a high possibility of showing improvement by changing the caregiving system.

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To evaluate the loss of biologically active cobalamin in milk during light-induced riboflavin degradation, various milk samples were exposed to fluorescent light (3, 500 lx) for 24 h at 4°C. Total cobalamin was extracted and assayed by the chemiluminescent method with the hog intrinsic factor, a mammalian cobalamin-binding protein. The cobalamin concentration was decreased by between 1% and 27%, depending on the type of milk tested. This loss of cobalamin may be indirectly due to the free radicals formed by light-induced riboflavin.

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A simple and selective HPLC method with electrochemical detection is described for measuring trans-resveratrol in grapes and their processed foods. This method can determine trans-resveratrol, whose retention time was ca. 12 min, with a commercially available ODS column by isocratic elution with a 0.05 M citric acid-disodium hydrogenphosphate buffer (pH 3.0) /methanol (= 60 : 40, v/v) containing 3.5 mm sodium octanesulfonate. The theoretical detection limit of trans-resveratrol was 2.28 ng/ml at a signal to noise ratio of 3. The concentrations of resveratrol that could be determined were 3.42 μg/ml for red wine, 0.39 μg/ml for white wine, 0.20-0.88 μg/ml for beverages, and 2.30 μg/g for grapes.

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[in Japanese]

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