The postingestive consequences of fat condition preferences for flavors associated with high dietary fat.

To investigate whether children acquire conditioned preferences for flavors associated with high dietary fat content, 27 3- and 4-year-old children participated in a series of 12 conditioning or mere exposure sessions. Following an overnight fast, children who participated in conditioning trials consumed fixed quantities of a flavored yogurt drink that on half the days was high in fat and energy (954 kJ, 18 g fat/150 g serving) or contained no fat (277 kJ, 0 g fat/150 g serving). Children in the conditioning group consumed 150 g servings, children in the mere exposure group tasted 16 g or less of these same stimuli. Preferences were assessed before and after conditioning when the children were hungry and also postconditioning when the children were satiated. Results provided evidence for conditioned preferences based on the postingestive consequences of dietary fat. Children in the conditioning group learned to prefer the high-density paired flavor over the low-density paired flavor, and increased their preference for the high-density paired flavor from pre- to postconditioning. Children in the mere exposure group showed positive shifts in preference for both the fat-free and the high-fat paired flavors. In the conditioning group, preferences for the high-fat flavor was depressed by satiety, whereas the preference of the mere exposure group did not vary with hunger state. Conditioned flavor preferences, based on the postingestive consequences of fat intake, may contribute to children's preferences for foods high in dietary fat.

Guanine-7-oxide, a novel antitumor antibiotic.

A new antibiotic, PD 113,876, was isolated from the culture broth of a Streptomyces sp. and was shown by X-ray diffraction analysis to be the N-7 oxide of guanine. This novel antimetabolite is very active in vivo against L1210 lymphocytic leukemia.

Daily variation in plasma zinc concentrations in women fed meals at six-hour intervals.

Ten pre-menopausal women participated in two studies to measure the daily variations in plasma zinc when meals were fed at 6-h intervals and to determine if the response was related to shifts in serum insulin, glucose, calcium, or phosphorus concentrations. In Study 1, identical meals were fed at 6-h intervals for 2 d, and blood was sampled 8 times between each meal. In Study 2, the women fasted from 1800 h on d 1 to noon the next day, and blood was sampled hourly from 0700-1200 on d 2. The postprandial plasma zinc response was similar following all four meals and accounted for 50% of the total within subject variation in plasma zinc. A small (2-6%) increase occurred within the first 60 min; then plasma zinc declined to a low point at 4 h after the meal. This characteristic pattern was not observed during the fasting study. Serum phosphorus varied consistently after each meal with a net efflux from circulation that preceded an efflux of zinc by 2 h. The postprandial response of serum glucose and insulin were related to the postprandial plasma zinc response measured 6 h earlier; the variables were not correlated at concurrent time points. The data show that food intake is a determinant of the daily variations in plasma zinc. The net efflux of zinc from circulation following meals may reflect hepatic zinc uptake in association with an increase in postprandial liver metabolism.

Butirosin, a new aminoglycosidic antibiotic complex: isolation and characterization.

Butirosin, a new water-soluble aminoglycosidic antibiotic complex, active against gram-positive and gram-negative bacteria, has been isolated from fermentation filtrates of Bacillus circulans by ion exchange. The complex has been resolved into isomeric A and B components, C(21)H(41)N(5)O(12), by means of Dowex 1 x 1 or Dowex 1 x 2 chromatography. Properties of the free bases and the N, N', N'', N'''-tetraacetyl derivatives of butirosin A and B are given.

Pre-breakfast plasma zinc concentrations: the effect of previous meals.

The aim of this study was to determine the effect of the time and size of the last meal of the previous day on pre-breakfast 0700 hours plasma zinc concentrations. Nine healthy women were each studied on four separate occasions when the same standard meal was taken either at 1800 hours (study 1); double meal at 1800 hours (study 2); at 2400 hours (study 3); or at 1800 hours and 2400 hours (study 4). Mean differences between 1800 hours (day 1) and 0700 hours (day 2) plasma zinc (mumol/L +/- SEM) were 1.6 +/- 0.3 for study one; 0.8 +/- 0.3 for study two; 0.1 +/- 0.3 for study three and 0.0 +/- 0.2 for study four. The differences for studies two, three and four were significantly less than the difference for study one (p less than 0.05). The difference for study four was also less than the difference for study two (p less than 0.05). Changes in time and size of the meals accounted for 59% of within-subject variation in 0700 hours plasma zinc concentrations. It is concluded that pre-breakfast 0700 hours plasma zinc concentrations are affected by the time and the size of the meal(s) consumed the previous evening.