Michel Hanocq

Plasma and erythrocyte zinc, copper and selenium in cystic fibrosis

ABSTRACT. Plasma and erythrocyte zinc, copper and selenium were measured in 20 cystic fibrosis children, aged 7 to 19 years. Mean plasma zinc and copper levels were not different from those in age‐matched controls but very low zinc levels occurred sporadically. Plasma zinc concentrations were significantly lower in patients with moderate‐to‐severe growth retardation and with severe pulmonary disease as compared to patients without growth failure and with moderate pulmonary disease. Mean erythrocyte zinc (40.8 μg/g Hb ±9.2) and copper levels (3.56 μg/g Hb ±0.50) were very significantly increased (30.4 μg/g Hb ±5.2 and 2.73 μg/g Hb ±0.30 respectively, for age‐matched controls). Mean plasma and erythrocyte selenium levels (63 ng/ml ±15 and 329 ng/g Hb ±86) were significantly lower than those in age‐matched controls (82 ng/ml ±13 and 404 ng/g Hb ±116). The trace element concentrations in erythrocytes are discussed in relation to the activities of the copper‐ and zinc‐containing enzyme superoxide dismutase and the seleno‐enzyme glutathione peroxidase. We consider that more data on trace element metabolism in CF should be collected before specific supplementation is considered.

Erythrocyte and plasma trace element levels in clinical assessments : Zinc, copper, and selenium in normals and patients with Down's syndrome and cystic fibrosis.

On the basis of original investigations on zinc, copper, and selenium levels in plasma and erythrocytes of Downs syndrome (DS), cystic fibrosis (CF), and control subjects, the possible importance of erythrocytic trace element concentrations in clinical analysis is emphasized. Red blood cell levels of copper and zinc were found significantly increased in both groups of diseased patients as compared to age-matched controls, although plasma levels did not statistically differ. Plasma selenium levels were significantly lower in both investigated groups, but red blood cell levels were only decreased in CF and were not different from controls in DS. Significant differences were also found between zinc, copper, and selenium levels in erythrocytes of two control groups originating from distinct geographic areas, although plasma levels were not statistically different. Some factors likely to modify trace element concentrations in erythrocytes are examined and a more systematic determination of these levels is suggested for use in clinical analysis.

Pharmacokinetic study of orally administered zinc in humans: evidence for an enteral recirculation.

SummaryStarting from the experimental design of the established ‘Zinc Tolerance Tests’, the absorption and distribution of the essential trace element zinc in humans was investigated in 10 subjects by performing a pharmacokinetic study of the serum zinc profile after oral administration of a pharmacological dose of the metal, i.e. 0.69 mmol (45 mg) zinc as ZnSO4.7 H2O. The adopted experimental conditions include frequent measurements of serum concentrations, a total investigation time of 8 h after ingestion, and a correction of basal zinc levels taking into account the circadian variation. Rebound effects were evidenced in the time versus concentration curves showing a regular recycling of the element in the digestive tract. Estimation of the parameters by an original method allowed us to calculate the characteristics of the cycles. The first one occurred after 1.4 h, before the time needed for appearance of the maximum concentration which was around 2.3 h, and exhibited mean reabsorption of 70% of administered dose. The subsequent ones, maximum 5 during the investigation period, appeared at regular intervals of approximately 1.2 h, with a decrease in the quantity reabsorbed. These observations are consistent with the previously reported endogenous secretion of zinc, a physiological mechanism contributing to zinc homeostasis.

Macro Ionization Constants of Hydroxyzine, Cetirizine and an Analog

Abstract Thermodynamic dissociation constants of piperidine and piperazine compounds have been determined at 20°C by combining two experimental techniques. These compounds have chromophoric changes dependent upon the pH of the solution. Using spectrophotometric measurements and potentiometric titration data, all constants have been calculated. the values determined by means of both methods are in good agreement. Especially the two overlapping macroconstants of cetirizine have been computed using an adequate algorithm. Unexpectedly, pKal of [2-[4-[[4-chlorophenyl)phenylmethyl]-1-piperazinyl]ethoxy]acetic acid (CETIRIZINE) has been shown to be much lower than pKal of its analog ([2-[2-[4-(diphenylmethylene)-1-piperidinyl] ethoxy] ethoxy] acetic acid), probably because of an electronic effect : an intramolecular hydrogen bond between the carbonyl of the carboxylic acid group and the protonated nitrogen atom bearing the ethoxyacetic chain.