Cerebrospinal fluid free choline in movement disorders of paediatric onset.

We measured free choline in cerebrospinal fluid (CSF) of 78 patients with movement disorders of paediatric onset and various controls as a putative index of central phospholipid metabolism. Most of the disorders studied were myoclonic disorders, such as progressive myoclonus epilepsy, the opsoclonus-myoclonus syndrome, and essential myoclonus, but other movement disorders, interictal seizure disorders, and different neurological and nonneurological disorders were also included. There were no significant differences in CSF choline concentrations in myoclonic disorders or other movement disorders compared with controls. The CSF choline levels were lowest in children with seizure disorders including progressive myoclonus epilepsy. In progressive myoclonus epilepsy, the CSF choline values resembled other epileptic disorders rather than other myoclonic disorders. When all the data were analysed collectively, no significant relation of CSF choline was found to patient age, gender, aliquot of CSF measured, or the length of time the sample was stored at -70 degrees C. Separate analyses of data from children and adults showed a trend toward a biphasic relation between patient age and CSF choline which could be pursued in developmental studies of normal subjects. Reduced CSF choline may indicate increased choline incorporation into brain phospholipids, disturbances of choline metabolism, decreased choline release, or non-neural factors.

Vitamin E toxicity in neonatal piglets.

Intravenous vitamin E was associated with the deaths of 38 infants in the US in 1984. Because the vitamin E preparation used contained both vitamin E and a high level of polysorbate detergent, the etiology of the syndrome remains unknown. In this study, we determined the tissue disposition of an intravenous preparation of vitamin E solubilized with polysorbate (E-Ferol) in neonatal piglets. One to two-day-old piglets were injected daily with 50 IU/kg/d of vitamin E for a period of 13 days. Other groups were injected intramuscularly, or with a slow, 7 h intravenous infusion with 50 IU/kg/d vitamin E for six days. Massive splenic accumulation of vitamin E (16,004 micrograms/g vs 73 micrograms/g in controls) occurred following rapid injection, with far lesser concentrations in the liver and lung. Levels of vitamin E in the kidney and heart were only slightly above control. Tissue changes correlated with dosage and duration of vitamin E administration and suggested massive accumulation of vitamin E in cells of the mononuclear phagocyte system. Following slow intravenous infusion the highest levels of vitamin E occurred in the liver rather than spleen. Intramuscular injections at similar doses produced slight, but insignificant changes in tissue levels of vitamin E. We speculate that rapid intravenous injection of vitamin E emulsions produces massive accumulation in phagocytic cells of the spleen and to a lesser extent liver and lung, possibly leading to increased susceptibility to sepsis and/or abnormal pulmonary function. Slow infusions of vitamin E produce major accumulations in the liver rather than spleen.(ABSTRACT TRUNCATED AT 250 WORDS)

Therapeutic drug monitoring in a pediatric laboratory.

Therapeutic drug monitoring using a new and faster high pressure liquid chromatographic (HPLC) method is discussed. Analysis of chloramphenicol and succinate esters and a large number of anticonvulsive drugs can be carried out using the same buffer and reverse-phase HPLC column by changing the solvent concentration to reflect the choice of drugs. A buffer prepared from 0.02 M sodium acetate and trifluoroacetic acid provides an optimal mobile phase for separation of a wide variety of drugs commonly used in pediatric medicine. Sample preparation and the use of special internal standards without extensive extractions provides excellent accuracy, reliability and sensitivity, and requires a minimum of preparation.

N-Acetylcysteine therapy of acute heavy metal poisoning in mice.

Therapy of acute heavy metal poisoning is currently limited to a group of moderately toxic drugs containing sulfhydryl groups. N-Acetylcysteine (NAC) was used in these studies to determine if this sulfhydryl containing amino acid would reduce the overall mortality of a group of heavy metal compounds. D-Penicillamine and dimercaprol (BAL) were also used for comparison. Groups of at least 100 mice (28 g) were injected subcutaneously with 2-190 mg/kg of copper, arsenic, thallium or cadmium for LD50 determinations. Other groups were injected 30-60 min later with NAC (200 mg/kg), d-penicillamine (50 mg/kg), or BAL (10 mg/kg), and mortality was monitored for 2 weeks. The LD50 for each treatment group was determined by regression analysis of log-probit transformed data. In arsenite treatment group the survival time was lengthened in NAC-treated animals although the LD50 was not significantly changed. BAL was only slightly more effective than NAC. The mortality in animals given copper and treated with NAC was almost eliminated, except at the highest doses. BAL provided the greatest protection, whereas d-penicillamine produced the least. The LD50 of copper was significantly changed from 60.5 mg/kg in control groups to 139 mg/kg in NAC-treated groups, and to 150 mg/kg and 91 mg/kg in BAL and d-penicillamine-treated groups. NAC and BAL were totally ineffective in the treatment of thallium and cadmium poisoning.

Kinetics of primidone metabolism and excretion in children.

The metabolism and excretion of orally administered primidone was studied in 12 children, aged 7 to 14 yr during long-term dosing. Plasma concentrations of primidone (Pr) peaked at 4 to 6 hr and declined exponentially from 6 to 24 hr, with half-life (t1/2) values ranging from 4.5 to 11 hr. A mean of 92% (72% to 123%) of the administered dose was recovered within 24 hr from the urine as Pr and its metabolites. Of the total Pr daily dose, 42.3% (15.2% to 65.9%) was recovered as unchanged drug, 45.2% (16.3% to 65.3%) as phenylethylmalonamide (PEMA), and 4.9% (1.1% to 8.0%) as phenobarbital (Pb). The mean rate constant for conversion of Pr to PEMA (K1) was 0.0424 hr-1, for conversion of Pr to Pb (K2) was 0.0045 hr-1, and for excretion of unchanged Pr (K3) was 0.0389 hr-1. Of Pb excreted, 43% (13% to 100%) was unchanged, 15% (0% to 27%) was unconjugated p-OH Pb, 20% (0% to 44%) was conjugated p-OH Pb, and 22% (0% to 33%) was conjugated 3,4-OH Pb. KE appears to be important determinant of the steady-state plasma concentration of Pb, but interindividual differences in K2 have little influence on the overall rate constant for elimination of Pr.