OBJECTIVES Nutritional aspects of breakfast, plasma levels of glucose and beta-hydroxybutyrate, body mass index and academic performance have been studied in urban and rural children (Extremadura, Spain). METHODS Representative samples of schoolchildren (3 to 12 years old, random cluster-sampling in schools). RESULTS Children's mean caloric intake with breakfast was 331 kcal. Rural populati...

Several compounds were evaluated in vitro as alternative electron sinks to ruminal methanogenesis. They were incubated with ruminal fluid, buffer mixture, and finely ground alfalfa hay for 24 h, at 0, 6, 12, and 18 mM initial concentrations. The propionate enhancer oxaloacetic acid, the butyrate enhancer beta-hydroxybutyrate, and the butyrate unsaturated analog 3-butenoic acid were ineffective ...

Effects of weaning age on blood glucose, ketones, and nonesterified fatty acids were examined using 16 Holstein heifer calves. Animals entered the study at 6 +/- 3.5 d of age and were fed 1.8 kg of milk twice daily to 28 (early weaning) or 56 d (late weaning) and a commercial pelleted calf starter from 0 (early) or 28 d (late). Blood was sampled once weekly for 14 wk and analyzed for beta-hydro...

In a previous study, we demonstrated that topical D-beta-hydroxybutyrate ameliorates corneal epithelial erosion and superficial punctate keratopathy in a rat model of dry eye disease. In the current investigation, we performed a prospective, randomized, multicentre, double-blind, placebo-controlled study to assess the safety and efficacy of 1% D-3-hydroxybutyrate eye drops in patients with dry ...

Background: It was hypothesized that under apparently good management practices in dairy farms, some cows may not be metabolically perfect during the breeding period and this may affect their performance. Aims: This study was conducted to assess probable metabolic drawbacks in mid-lactation dairy cows affecting their performance. Methods: Thirt...

The impact of fasting on IHL (intrahepatic lipid) content in human subjects has not been investigated previously, but results indicate that it may change rapidly in response to metabolic cues. The aim of the present study was to measure IHL content after fasting and to correlate this with circulating lipid intermediates. A total of eight healthy non-obese young males were studied before and aft...

The bacterial species Escherichia coli has proven to be a powerful tool in the molecular analysis of polyhydroxyalkanoate (PHA) biosynthesis. In addition, E. coli holds promise as a source for economical PHA production. Using this microorganism, clones have been developed in our laboratory which direct the synthesis of poly-beta-hydroxybutyrate (PHB) to levels as high as 95% of the cell dry wei...

Several DNA regions containing genes involved in poly-beta-hydroxybutyrate (PHB) biosynthesis and degradation and also in fatty acid degradation were identified from genomic sequence data and have been characterized in the serine cycle facultative methylotroph Methylobacterium extorquens AM1. Genes involved in PHB biosynthesis include those encoding beta-ketothiolase (phaA), NADPH-linked acetoa...

A rapid and reproducible method for the assay of 14C radioactivity in ketone bodies is described, based on the heat lability of acetoacetate and the ability of beta-hydroxybutyrate to quantitatively bind to and elute from an ion exchange resin. Potential interference from 14C activity in the ketone body metabolites (CO2, bicarbonate and acetone) during infusion of 14C-labeled ketone bodies is e...