No abstract

Accurate assessment of dietary phosphorus intake is necessary to prevent hyperphosphatemia. The aim of this study was to evaluate the 24-h urine collection method for estimation of phosphate intake in healthy males. Two experiments, a 1-day and a 5-day loading test, were performed. After an overnight fast, subjects consumed test meals, 24-h urine collection was performed, and blood samples were obtained. In the 5-day loading test, a phosphorus supplement was orally administered on day 3. The association between the phosphorus content of test meals and urinary excretion, anthropometric indices, and blood biomarkers was analyzed to develop a more precise formula for estimating phosphorus intake. In the 1-day loading test, the standard deviation of predictive phosphorus intake, based on multiple linear regression analysis, was less than that for the phosphorus absorption rate. In the 5-day loading test, urinary phosphorus excretion was similar on days 2, 4 and 5, but was significantly higher on day 3 after phosphorus supplementation. Our results indicate that estimation of dietary phosphorus intake with the 24-h urine collection method, using the amount of phosphorus and urea nitrogen excretion, may increase the precision of short-term monitoring.

BackgroundNocturnal eating have recently increased. Serum phosphorus levels and regulators of phosphorus have circadian variations, so it is suggested that the timing of eating may be important in controlling serum phosphorus levels. However, there have been no reports on the effects of nocturnal eating on phosphorus metabolism.The objective was to evaluate the effects of nocturnal eating on phosphorus metabolism.MethodsFourteen healthy men participated in two experimental protocols with differing dinner times. The design of this study was a crossover study. The subjects were served test meals three times (breakfast; 07:30 h, lunch; 12:30 h, dinner; 17:30 or 22:30 h) a day. Blood and urine samples were collected to assess diurnal variation until the following morning.ResultsThe following morning, fasting serum phosphorus levels in the late dinner group were markedly higher than those in the early dinner group (p < 0.001), although serum calcium levels were maintained at approximately constant levels throughout the day in both groups. Fluctuations in urinary calcium excretion were synchronized with the timing of dinner eating, however, fluctuations in urinary phosphorus excretion were not synchronized. Urinary phosphorus excretions at night were inhibited in the late dinner group. In the late dinner group, intact parathyroid hormone levels didn’t decrease, and they were significantly higher in this group compared with the early dinner group at 20:00 h (p = 0.004). The following morning, fasting serum fibroblast growth factor 23 levels in the late dinner group had not changed, but those in the early dinner group were significantly increased (p = 0.003). Serum free fatty acid levels before dinner were significantly higher in the late dinner group compared with the early dinner group.ConclusionsOur results indicate that nocturnal eating inhibits phosphorus excretion. It is suggested that nocturnal eating should be abstained from to manage serum phosphorus levels to within an adequate range.

Echo-trace-analysis was applied to single echo-traces of Antarctic krill to estimate in situ swimming orientation, swimming speed, and backscattering pattern. Acoustic data were collected with a split-beam echosounder operating at 70 kHz on 11 January 2005 during the Southern Ocean survey by the training vessel Umitaka-maru of Tokyo University of Marine Science and Technology. While the acoustic data were collecting, the ship speed was 2 knots. A pulsewidth and a pulse-repetition-period of the echosounder were 0.6 ms and 0.27 s, respectively. Krill aggregations were observed at the depth range 15–30 m from the hull-mounted transducer and at upper and lower edges of them some single echo-traces were visually recognized on echograms. In this work, these echo traces were analyzed. As preliminary results, the average swimming orientation was 4.0 deg with a standard deviation of 14.2 deg and the average swimming speed was 0.33 m/s with a standard deviation of 0.16 m/s. The average swimming orientation was close to the orientation observed with a video plankton recorder by Lawson et al. [J. Acoust. Soc. Am. 119(1), 232–242 (2006)]. The estimated backscattering patterns showed peaks at incident angles around −10 to 10 deg and were similar to the patterns predicted by theoretical models.