RESUMEN
We describe a microassay for measuring galactose (Gal) and galactose 1-phosphate (Gal-1-P) in dried blood spots. After a coupled enzyme reaction involving galactose dehydrogenase (GADH, EC 1.1.1.48) and alkaline phosphatase (AP, EC 3.1.3.1) in a microplate well, NADH fluorescence is measured by a highly sensitive fluorometric microplate reader, capable of rapid measurement of fluorescence (2 min per 96 samples). Within- and between-run CVs for measurements of Gal at 90 mg/L with Gal-1-P at 130 mg/L were both less than 5% (n = 8), and analytical recoveries for Gal at 90 mg/L and Gal-1-P at 130 mg/L were 98% and 92%, respectively. Five hundred dried blood-spot samples can be assayed within 2 h, with full calculation of results by an on-line microcomputer. This rapid and reliable assay system is very useful for the routine screening of newborns for galactosemia.
Asunto(s)
Galactosemias/diagnóstico , Tamizaje Masivo/métodos , Femenino , Fluorometría/instrumentación , Galactosemias/sangre , Galactosafosfatos/sangre , Humanos , Recién Nacido , Masculino , Microquímica , Microcomputadores , Estadística como AsuntoRESUMEN
Carnitine status was evaluated in 12 patients with hyperammonemic attacks caused by a deficiency in ornithine transcarbamylase. We found decreased free carnitine and increased acylcarnitine levels in the serum, a decreased free carnitine content and an elevated acyl/free carnitine ratio in the liver, and increased excretion of free and acylcarnitine in the urine. Analyses of urinary acylcarnitine using the secondary ion mass spectrometry technique revealed increased amounts of acetylcarnitine and dicarboxylic acid derivatives. These data suggest that the patients had a secondary carnitine deficiency, possibly an aggravating factor in urea cycle dysfunction. After oral administration of L-carnitine (50 to 100 mg/kg/d) in two patients, hyperammonemic episodes were less frequent. Blood ammonia levels decreased significantly, accompanied by an increase in serum free carnitine levels.
Asunto(s)
Amoníaco/sangre , Carnitina/deficiencia , Enfermedad por Deficiencia de Ornitina Carbamoiltransferasa , Carnitina/análogos & derivados , Carnitina/análisis , Carnitina/uso terapéutico , Niño , Preescolar , Femenino , Humanos , Recién Nacido , Hígado/análisis , MasculinoAsunto(s)
Cromosomas Humanos Par 2 , Cromosomas Humanos Par 9 , Glaucoma/congénito , Trisomía , Humanos , Recién Nacido , Cariotipificación , MasculinoRESUMEN
Carnitine status was evaluated in 8 patients with partial ornithine transcarbamylase (OTC) deficiency and 19 patients with secondary carnitine deficiency, who were used as positive references. Laboratory findings indicated that all patients with OTC deficiency had secondary carnitine deficiency especially in hyperammonemic attack. After L-carnitine administration in 2 patients with OTC deficiency, the number of attacks was significantly reduced in both cases.