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Biomedical subjects

R Parini

Publications and source records attributed to R Parini.

23 records · Page 2Linked to original sources
PubMed1981

Theophylline distribution in the premature neonate.

Theophylline (T) tissue distribution was studied in 11 premature newborns treated with T for prematurity apnea, who had died from severe pathology. To investigate the pattern of distribution of T, in particular the role of the blood-brain barrier in this period of life, two animal species were employed (rat and guinea pig), differing widely in their postnatal development. T was administered to the animals acutely and chronically and the resulting data were compared to human findings. In human prematures no specific accumulation and a wide variety in tissue concentrations, as in tissue/blood ratios, were observed. In the rat, unlike the guinea pig, brain/blood ratios of T concentration declined as postnatal age rose, suggesting that development of the blood-brain barrier plays a major role.

Aging↗
PubMed1981

Theophylline metabolism during the first month of life and development.

The metabolic pathway of theophylline (T) was studied in 12 newborns, one young infant, six children, and three adult volunteers. T was injected IV, and blood and urine samples were assayed for T, caffeine (C), and their metabolites by a high-pressure liquid chromatography technique. We confirmed the methylation of T to C in newborn infants but not in older subjects. Demethylation of T to 3-methylxanthine was found in the young infant, in children, and in adults, but not in newborns. The major products excreted by neonates were T, 1-methyluric acid, and 1,3-dimethyluric acid. Children excreted a larger fraction of methyluric acids than adults. Renal and body clearance of T and C are reported and discussed in relation to the age.

Adult↗
PubMed1980

Plasma glutamic acid levels in premature newborn.

24 premature, newborn infants were investigated for plasma glutamic acid (GA) levels before and after a normal milk feed, to ascertain if the ingestion of GA present in the milk could result in an increase of its plasma level. No increases were detected in plasma between 5 and 90 min after the feed. These results may be important in respect to the problem of the possible toxicity of monosodium glutamate (MSG) added to baby foods.

Animals↗
PubMed1980

Multiexponential elimination of gentamicin. A kinetic study during development.

The long-term disposition of gentamicin (up to 100-240 h) was studied in 13 premature newborns (33 weeks mean gestational age) and in 7 infants and children (1 month to 8 years). The data fitted bi- or triexponential curves with terminal half-lives averaging 51 and 37 h. Newborns showed lower values of body clearance, central compartment and steady state volumes of distribution than infants and children (respectively, 12.8 vs. 50.4 ml/min/1.73 m2, 9.03 vs. 17.5 liters/1.73 m2, and 15.7 vs. 35.5 liters/1.73 m2). The ratio between the amount of gentamicin predicted at steady state in the tissue compartment and in the total body was also significantly lower in newborns than in the older group (0.4 vs. 0.52). These data provide pharmacokinetic demonstration of an age dependence in gentamicin tissue distribution and excretion during the early stages of human development.

Adult↗