Many animal studies on improvement of lipid metabolism, using dietary components, fast the animals on the final day of the feeding. Although fasting has a significant impact on lipid metabolism, its time-dependent influence is not fully understood. We examined the effects of several fasting times on lipid metabolism. Rats fed with a semisynthetic diet for 2 wk were killed after 0 (9:00 am), 6 (7:00 am–1:00 pm), 9 (0:00 am–9:00 am), and 13 h (8:00 pm–9:00 am) of fasting. Compared to the 0 h group, marked reduction of liver weight and hepatic triacylglycerol content was observed in the 9 and 13 h groups. Activities of hepatic enzymes involved in fatty acid synthesis gradually decreased during fasting. In contrast, drastic time-dependent reduction of gene expression, of the enzymes, was observed. Expression of carnitine palmitoyltransferase mRNA was higher in the fasting groups than in the 0 h group. Our study showed that fasting has a significant impact on several parameters related to lipid metabolism in rat liver.

Two cases of D-lactic acidosis associated with short bowel syndrome are described. The administration of kanamycin to the patients showed a decrease in D-lactate in blood and urine in parallel with disappearance of metabolic acidosis. Bacteriological analyses of the fecal flora showed an increase in Lactobacillus buchneri in the first patient and Lactobacillus fermenti IVa in the second; both bacteria were sensitive to kanamycin. Quantification of in vitro production of D-lactate by each species of bacteria isolated from the feces revealed that Lactobacillus produced more D-lactate than other species of bacteria. These observations indicate that Lactobacillus may play an important role in the induction of D-lactic acidosis in patients with short bowel syndrome.

A patient with the hyperornithinemia, hyperammonemia, homocitrullinuria syndrome is described. This patient represents the 12th documented case of this rare, presumably autosomal recessive condition. Increased levels of ammonia, ornithine and homocitrulline were demonstrated in blood and cerebrospinal fluid. The blood ammonia concentration could be lowered by supplementation of the diet with low doses of arginine. High doses of arginine precipitated seizures, although plasma levels of arginine and ornithine were not altered. The uptake of ornithine by the particulate fraction of the patient's fibroblasts was lower than that of controls, but still measurable. It is suggested that HHH patients have a partial impairment of the uptake of ornithine by mitochondria.

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The intracellular pH of control fibroblasts and of fibroblasts of a HHH -syndrome patient have been determined. Values of 6.94 +/- 0.15 and 7.05 +/- 0.14 for control and patient fibroblasts, respectively, were found. By means of analyses of malate in the cytosolic and particulate fractions of the fibroblasts the differences in pH between these two cellular compartments were estimated to be 1.34 +/- 0.12 and 1.38 +/- 0.18 for control and patient, respectively. Neither difference was statistically significant. The decrease in the rate of ornithine uptake by mitochondria of the patient's fibroblast is therefore not due to an increased intramitochondrial pH.