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Biomedical subjects

R L Boeckx

Publications and source records attributed to R L Boeckx.

28 records · Page 2Linked to original sources

Reference values for cerebrospinal fluid glutamine concentration in infants.

We measured cerebrospinal fluid glutamine concentration in a reference group of 85 newborn to 30-month-old infants. All of the spinal taps were performed for the diagnosis of illnesses unrelated to hyperammonemia or hepatic encephalopathy. We also analyzed samples from patients with meningitis or cerebral hemorrhage, or who were receiving total parenteral nutrition. The mean glutamine concentration in cerebrospinal fluid in the reference group was somewhat lower than values reported for older children and adults. Values were significantly higher in patients with meningitis or cerebral hemorrhage and in those infants receiving total parenteral nutrition.

Age Factors↗

Comparison of a high performance liquid chromatographic and an enzyme immunoassay technique for quantitation of theophylline in serum.

High performance liquid chromatograhic (HPLC) and enzyme immunoassay (EMIT) methods for quantitating theophylline concentrations in serum were evaluated. For both methods, standard curves were linear over the therapeutic range of serum concentrations. Precision was acceptable, with coefficients of variation being less than 9%. The HPLC assay was slightly, but not significantly, more precise. No interference was noted in either method by caffeine, theobromine, diphylline, 8-chlorotheophylline, or by metabolites such as 1-methylxanthine, and 3-methylxanthine, or by potentially interfering compounds such as urea and uric acid. The two methods correlated well, with a correlation coefficient of 0.98%. The enzyme immunoassay was superior in terms of lower costs, greater ease of performance, and potential for automation.

Chromatography, High Pressure Liquid↗

The neurological manifestations of chronic inhalation of leaded gasoline.

Abnormal neurological signs were found in 46 of 50 children and adolescents chronically sniffing leaded gasoline. These abnormalities resolved within eight weeks in all but one case. Exaggerated deep reflexes, postural tremor and evidence of cerebellar dysfunction occurred in a highly significnat number of patients. Forty-nine had blood lead levels greater than or equal to 40ug/dl. The mean blood lead levels were significantly higher in those with (a) abnormally brisk deep reflexes and (b) with evidence of cerebellar dysfunction, than in those without these findings. Five optional treatment regimes were employed and a classification was used, based on clinical findings, initial blood lead levels and the response to the calcium disodium edatate mobilization test. 39 patients received chelation therapy. These data suggest that neurological manifestations occur frequently in those abusing leaded gasoline and that chelation therapy has an important place in their management.

Adolescent↗

Gasoline sniffing and tetraethyl lead poisoning in children.

Two cases of acute organic lead poisoning following gasoline sniffing, with one death, are reported. Signs of lead encephalopathy with elevated blood lead levels and markedly decreased levels of erythrocytic delta-amino levulinic dehydratase (ALAD) were demonstrated. Erythrocytic ALAD activity was used as a screening test for the detection of tetraethyl lead (TEL) poisoning in a group of 43 children who were presumed gasoline sniffers. Their mean ALAD activity was 190 units compared to a mean of 538 units for a control group. A survey of schoolchildren in another isolated community revealed that 59% had decreased ALAD activity, which correlated well with a history of gasoline sniffing. Only 5% of the children had blood lead levels over 40 microgram/dl. The two surveys herein reported suggest that there may be large numbers of children living in isolated communities who are suffering from TEL poisoning as a result of gasoline sniffing. This constitutes a major medical, public health, and social problem heretofore virtually unrecognized.

Adolescent↗

Effect of biotin on ribonucleic acid synthesis.

A single injection of biotin to biotin-deficient rats produces a two-fold increase in the incorporation, both in vivo and in vitro of precursors into nucleic acids as early as 2 h after the biotin treatment. The specific activity of the precursor pool is not affected by biotin. Analysis of the polysome profile at various times following biotin treatment and a kinetic study of the effect of excess poly(U) on the incorporation of phenylalanine by cell-free amino acid incorporation experiments indicate a marked decrease in messenger-free ribosomes in rat liver after biotin administration.

Animals↗

Biotin-mediated protein biosynthesis.

The effect of administration of biotin to biotin-deficient rats on protein biosynthesis was studied. Biotin treatment resulted in stimulation by more than twofold of amino acid incorporation into protein, both in vivo and in vitro in rat liver, pancreas, intestinal mucosa and skin. Analysis of the products of amino acid incorporation into liver proteins in vivo and in vitro indicated that the synthesis of some proteins was stimulated more than twofold, but others were not stimulated at all. This indicates a specificity in the stimulation of protein synthesis mediated by biotin.

Animals↗

The potential toxicity to neonates of multivitamin preparations used in parenteral nutrition.

This study compares two groups of infants weighing less than 1500 g at birth. In the propylene glycol (PG) group, 30 infants received MVI-Concentrate containing 300 mg of PG daily with their intravenous nutrition (ivn), and vitamin E, 50 mg/week by intramuscular injection. In the mannitol group, 30 infants received MVI-Pediatric (containing 245 mg mannitol), 65% of a vial/day. Serum and urine osmolality, serum PG, blood-urea-nitrogen, creatinine, sodium, and glucose were measured on days 0, 2, 5, 12, 19, 26, 33 and 40 of ivn. Weight, urine output, and fluid intake were measured daily. Vitamin E levels were measured on days 5, 26, and 33 of ivn. There were no significant differences between the groups in birth weight, gestational age, sex, age, or weight at start of ivn. Our results indicated that neither MVI-Concentrate nor MVI-Pediatric was associated with a clinically significant diuresis. MVI-Pediatric, 65% of a vial/day, may produce higher than desirable blood levels of vitamin E, and use of drugs containing PG can produce significant blood levels of PG, in very low birth weight infants.

Diuresis↗