Markers of oxidative stress in fit, health-conscious elderly people living in the Paris area. The Research Group on Ageing (GERBAP)

Lipid peroxidation index and antioxidant indicators were assessed by biochemical means in 193 healthy elderly volunteers (103 men and 90 women), ages 70-89 y and living freely in the Paris area. Lipid peroxidation index was in the same range as in young adults. Zinc, copper, and selenium levels were satisfactory and similar to those in young adults, though the range of copper values tended to be higher. Copper and selenium levels were higher in elderly women than in men. However, for selenium values this sex-related difference disappeared in elderly volunteers > 75 y. Copper-zinc-superoxide dismutase and glutathione peroxidase activities were similar to those in young adults, with no influence of sex or age. Vitamin E and total carotene, closely related to cholesterol levels, were satisfactory. Our findings show that markers of oxidative stress are not influenced by old age when good health and nutritional status are preserved, as in this selected population.

[Reference intervals and biological profile in a group of healthy elderly population in the Paris region]. / Intervalles de référence et profil biologique d'une population de sujets âgés "en bonne santé" habitant la région parisienne. (Group d'évaluation et de recherche des biologistes de l'APHP).

The superimposition of pathological processes on ageing-related metabolic changes makes the interpretation of laboratory data difficult in the elderly. Therefore, in order to establish reference values of anthropometric, hematological and biochemical variables, we have carefully selected fit, health-conscious elderly subjects on the basis of clinical and biological criteria. We observed a trend for a wider range of values than in young adults. For some variables, the values were shifted down (eg: albumin, vitamin D) or up (eg: glucose, urea, cholesterol, ferritin), as a result of slow metabolic changes or progressive functional decline of different organs. The high prevalence of hypovitaminosis D was worthy of note, particularly in women, suggesting a high risk of deficiency.

[Adaptation of a method for determining serum iron after deproteinization on a parallel analyzer]. / Adaptation d'une méthode de dosage du fer sérique après déprotéinisation sur analyseur parallèle.

The study of the determination of iron in sera by a bathophenanthroline method after deproteinization, has been realized according to the protocol Valtec conceived by SFBC, after adaptation on a FP9 parallel analyzer. The critical study of this adaptation included trials of within run precision (CV of 1.25%), total precision (CV 2.29 to 4.66%) as also evaluation of analytical range: the limit of linearity is 140 mumol/l. The evaluation of inaccuracy performed with patient specimens leads to establishment of follow up norms and interpretation norms of allometry line. Our whole results are in agreement with the performance standards of the protocol for the validation of methods published by the Société Française de Biologie Clinique. Finally the described method is quick acting, reliable and very inexpensive.

[Adaptation of a diazoreaction method for determining total and conjugated bilirubins on a parallel analyser]. / Adaptation d'une méthode de dosage par diazoréaction des bilirubines totale et conjuguée sur un analyseur parallèle.

A diazoreaction method of estimation of bilirubin has been adapted on a FP9 parallel analyzer. Biotrol's kit could be used only after modifications of the protocol. The critical study of this adaptation included trials of within run precision (CV 1.93 to 4.42%), total precision (CV 2.59 to 6.66%) as also evaluation of analytical range: the limit of linearity is 340 mumol/l. The evaluation of inaccuracy performed with patient specimens leads to establishment of follow-up norms and interpretation norms of allometry line. Our whole results are in conformity with the performance standards of the protocol for the validation of methods published by the Société Française de Biologie Clinique. Finally the described method is quick acting, reliable and very inexpensive.

Aminotransferases in elderly people: influence of pyridoxal 5'-phosphate addition on the determination of serum aminotransferases in healthy elderly subjects.

Aspartate aminotransferase (ASAT) and alanine aminotransferase (ALAT) activity was measured in a group of 81 healthy subjects over 70 years of age and another of 180 younger persons, in order to investigate histograms and means of aminotransferase values in both groups and the variation in stimulation of these enzyme activities by pyridoxal 5'-phosphate (P5P) added in vitro. It was found that ASAT and ALAT mean values were significantly higher in both groups in the presence of P5P, than in the absence of P5P. ASAT and ALAT mean values obtained with and without P5P in old people were similar to those found in young subjects. In addition, mean stimulation percentages by P5P were identical in both groups.