Psyllium fiber reduces rise in postprandial glucose and insulin concentrations in patients with non-insulin-dependent diabetes.

The ability of psyllium fiber to reduce postprandial serum glucose and insulin concentrations was studied in 18 non-insulin-dependent diabetic patients in a crossover design. Psyllium fiber or placebo was administered twice during each 15-h crossover phase, immediately before breakfast and dinner. No psyllium fiber or placebo was given at lunch, which allowed measurement of residual or second-meal effects. For meals eaten immediately after psyllium ingestion, maximum postprandial glucose elevation was reduced by 14% at breakfast and 20% at dinner relative to placebo. Postprandial serum insulin concentrations measured after breakfast were reduced by 12% relative to placebo. Second-meal effects after lunch showed a 31% reduction in postprandial glucose elevation relative to placebo. No significant differences in effects were noted between patients whose diabetes was controlled by diet alone and those whose diabetes was controlled by oral hypoglycemic drugs. Results indicate that psyllium as a meal supplement reduces proximate and second-meal postprandial glucose and insulin concentrations in non-insulin-dependent diabetics.

Reduction of glycemic and lipid levels in db/db diabetic mice by psyllium plant fiber.

The soluble plant fiber psyllium significantly reduced fasting glucose and total cholesterol levels in the C57BL/KsJ db/db diabetic mouse relative to placebo-fed mice. Insulin levels were significantly higher in psyllium-fed than placebo-fed animals, indicating this fiber may delay the progression of diabetes in the animal model. High-density lipoprotein cholesterol levels rose moderately in both psyllium- and placebo-fed animals during the study, whereas triglyceride levels remained unchanged in both groups. Psyllium's effect on glycemic, lipid, and hormone parameters was not explained by weight loss or reduced food intake; these were similar in psyllium- and placebo-fed animals during the study. Our results show that psyllium fiber can beneficially moderate glycemic and lipid parameters in the db/db diabetes model.

Cell-free transcription and translation of isolated restriction fragments localize bacteriophage T5 pre-early genes.

In vitro transcription and translation of isolated restriction fragments containing all or part of the terminal redundancies of bacteriophage T5 localized virtually every pre-early gene to a small 6.3-kilobase BglI fragment. Among these genes were those encoding the A1 and A2 proteins, which are responsible for complete entry of the viral genome into its host, and the deoxynucleoside 5'-monophosphatase. A 3.9-kilobase BglI fragment containing the remainder of the pre-early region induced no proteins under these same conditions. Proteins induced by fragments including the right and left terminal redundancies were also compared and found to be identical. DNA immediately flanking the pre-early regions induced few proteins in vitro. Thus, this technique has allowed the overall gene organization of the pre-early region of T5 to be described.

Partial purification and characterization of a uracil-DNA glycosylase from wheat germ.

A uracil-DNA glycosylase has been purified over 1,000-fold from wheat germ, the first such repair activity isolated from a higher plant. The enzyme has a molecular weight of approximately 27,000 and is resistant to metal ion chelators, but inhibited by high concentrations of either mono or divalent cations. This glycosylase is unable to release uracil from the mononucleotides dUMP and dUTP or from wheat germ RNA. Twelve pyrimidine analogues which closely mimic uracil structurally and the nucleoside uridine were examined for their ability to inhibit glycosylase activity. However, only 5-azauracil and 6-aminouracil inhibited enzymatic release of uracil to the same degree as uracil itself. An inhibitor induced by bacteriophage T5 which inhibits Escherichia coli uracil-DNA glycosylase has been shown not to affect the glycosylase isolated from wheat germ, indicating that these two enzymes differ. The ability of the wheat germ uracil-DNA glycosylase to completely remove available uracil from synthetic DNA substrates in which thymine had been replaced by uracil in varying percentages was also examined and found not to depend on percentage of uracil in the substrates.