The action of phenolic antioxidants, such as probucol, on various active oxygen species was investigated using luminol chemiluminescence and spin trapping with 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). The various active oxygen species, including hydroxyl radicals (Fenton reaction), superoxide anions, singlet oxygen and hypochlorite ions were examined with phenolic antioxidants under aqueous and nonaqueous conditions. Probucol showed a quenching effect on both superoxide anions and hypochlorite ions in nonaqueous solution. However, it had no effect on hydroxyl radicals. alpha-Tocopherol, a natural phenolic antioxidant, showed a stronger quenching effect on superoxide anions and hypochlorite ions than probucol, and quenched hydroxyl radicals in nonaqueous solution. Furthermore, Trolox showed a quenching effect on all active oxygen species in both aqueous and nonaqueous solution. The antioxidants were studied under comparable conditions in a series of test systems and the reactivity profiles depicted as 'radar charts' which are helpful for characterizing antioxidant action.

Antioxidants↗

PubMedDate not supplied

Identity elements of Escherichia coli tRNA(Ala).

Studies using the T7 transcription system revealed that the discriminator base A73 and the G20 in the variable pocket play important roles in the Escherichia coli alanine tRNA identity. The C60 in the T-loop, which is unique to alanine tRNA, was not found to be crucial for alanine identity. Anticodon replacement into the valine anticodon UAC did not decrease alanine charging activity, and no alanine charging activity was detected in the mutant valine tRNA possessing the alanine anticodon UGC.

Base Sequence↗

PubMedDate not supplied

Intraarterial digital subtraction angiography in detection of hepatocellular carcinoma.

To evaluate the usefulness of intraarterial digital subtraction angiography (IADSA) in hepatocellular carcinoma, IADSA was prospectively performed, combined with conventional film-screen angiography, in 40 patients in whom the tumor was histologically proven or highly suspected. Of the 16 main tumors less than 2 cm, IADSA detected 7 that were missed by film-screen angiography; 6 of these were less than 1 cm in size. With other diagnostic modalities including ultrasound, routine CT study, and CT after intraarterial Lipiodol injection, the detection rate of these tumors was low. IADSA's contribution is important in the detection of small hepatocellular carcinomas.

Adult↗

PubMedDate not supplied

1173C>T polymorphism in VKORC1 modulates the required warfarin dose.

The response to warfarin is highly variable among individuals and such variability is likely to have some genetic basis. We evaluted the effect of VKORC1 polymorphisms on warfarin response among Japanese, taking advantage of its unique population structure in which CYP2C9 *2 and *3 alleles are relatively rare. Thirty-one patients (12-34 years old; median, 22) on warfarin were recruited from a pediatric cardiology clinic. Genotyping of the C>T polymorphism at position 1173 in intron 1 of VKORC1 revealed that 26 patients (84%) were T/T homozygotes at nucleotide 1173, whereas 5 (16%) were C/T heterozygotes. Complete linkage disequilibrium was observed between the 1173C > T polymorphism and another polymorphism, the 3730G > A, in the 3' untranslated region. The C/T heterozyogtes at the 1173C > T polymorphism tended to require more warfarin than the T/T homozygotes, when adjusted for international normalized ratio (p = 0.003). Both the 1173C > T polymorphism and the 3730G > A polymorphism are likely to be inert from a functional standpoint. Rather, based on the complete linkage disequilibrium between 1173C > T and 3730G > A polymorphisms, we suspect that the actual change that defines the relative resistance to warfarin may be present in the proximity of these two polymorphisms.

Adolescent↗

PubMedDate not supplied

Nicotinamide, a poly (ADP-ribose) synthetase inhibitor, ameliorates B-cell function in partially depancreatized rats.

We studied the effect of nicotinamide, a poly (ADP-ribose) synthetase inhibitor, on B-cell functions in 7-week-old male Wistar rats after 90% pancreatectomy (Px). Nicotinamide (0.5 g/kg body wt.) was injected once a day i.p. from 1 week before the surgery, and the injection was continued for 12 weeks after Px. Plasma glucose levels were significantly lower in Px rats treated with nicotinamide (NA rats) than in Px rats without treatment. In in vitro experiments with perfusion of the isolated pancreas, insulin secretion induced by 16.7 mM glucose was blunted in Px rats whereas insulin secretion induced by 19 mM arginine was increased. Nicotinamide treatment restored glucose-induced insulin secretion to normal and partly suppressed the hyperresponse of insulin to arginine. In addition, nicotinamide partially restored the priming effect induced by 28 mM glucose. The insulin content of the perfused pancreas was slightly but significantly greater in NA rats than in Px rats. Histological examination revealed fibrotic degeneration and degranulation in the islets of Px rats, whereas the normal structure was retained in most islets of NA rats. These results suggest that nicotinamide ameliorates islet function in partially depancreatized rats.

Analysis of Variance↗