8OHdG levels in brain do not indicate oxidative DNA damage in Alzheimer's disease.

Accumulation of oxidative DNA damage has been proposed to underlie aging and neurodegenerative diseases such as Alzheimer's Disease (AD). The DNA adduct 8-hydroxy-2'-deoxyguanosine (8OHdG) is considered a good indicator of oxidative DNA damage. To investigate whether this type of DNA damage is involved in AD etiology, 8OHdG levels were determined in postmortem human brain tissue of controls and AD patients (in frontal, occipital, and temporal cortex and in hippocampal tissue).

The influence of dietary restriction on the metabolism of theophylline and antipyrine in the ageing female BN/BiRij rat.

The influence of ageing and dietary restriction (DR) on the in vivo activities of different P450 enzymes was studied longitudinally in female BN/BiRij rats. For this purpose, antipyrine (AP) and theophylline (TH) were used as substrates. The metabolic clearances of AP (CIm AP) and TH (CIm TH) were used as indicators for P450 enzyme activities in vivo.

The influence of aging on the metabolism of simultaneously administered hexobarbital enantiomers and antipyrine before and after phenobarbital induction in male rats: a longitudinal study.

The influence of aging on the metabolism of antipyrine (AP) and hexobarbital enantiomers (R-HB and S-HB) with and without phenobarbital (PB) induction was investigated in a longitudinal study in rats aged 6, 12, 24 and 30 months. The metabolic clearances of AP (Clm AP), R-HB (Clm R-HB) and S-HB (Clm S-HB) were used as indicators for P450 enzyme activities in vivo. This also included the assessment of the clearances of formation of three AP metabolites, 3-hydroxymethylantipyrine (Cl-->HMA), 4-hydroxyantipyrine (Cl-->OHA) and norantipyrine (Cl-->NORA).

Cortisol production rate and the urinary excretion of 17-hydroxycorticosteroids, free cortisol, and 6 beta-hydroxycortisol in healthy elderly men and women.

Background: Although many workers have tested adrenal function in the elderly, few have studied the effect of aging on cortisol production rate or urinary free cortisol or 6 beta-hydroxycortisol excretion, and none have published comparisons of these variables between old people of defined health status and young people.

Methods: We have measured cortisol production rate and the urinary excretion of free cortisol, 6 beta-hydroxycortisol, 17-hydroxycorticosteroids (Porter-Silber chromogens) and creatinine in elderly men and women screened by the SENIEUR protocol and in young men; 17-hydroxycorticosteroid and 6 beta-hydroxycortisol excretion were also measured in young women. The period of measurement was 24 h or, usually, 48 h.

The relationship between phenazone (antipyrine) metabolite formation and theophylline metabolism in healthy and frail elderly women.

The influence of aging on the metabolism of phenazone (antipyrine), and the relationship between the formation of 3 phenazone metabolites and the metabolic clearance of theophylline in healthy and frail elderly women, were examined. Whereas the elimination half-life did not change, clearance of phenazone decreased by about 50% with age in healthy women receiving phenazone without theophylline. However, the summation of the urinary recovery of phenazone and the measured metabolites, expressed as percentage of the phenazone dose, was lower in the healthy elderly (37 +/- 9% vs 74 +/- 15%).