Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0029713 (immaturity)
 4,335 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mean urinary excretion values of some phenolic acids and alcohols have been measured by gas chromatography in 44 neonates (36 males, 6 females) during the first 2 days and days 3-7 of life, and the effect of prematurity and jaundice assessed. 4-Hydroxy-3-methoxymandelic acid (VMA) output rises immediately after birth in term but not in preterm infants. A similar increase in homovanillic acid (HVA) output was restricted to nonjaundiced term babies; in nonjaundiced preterm babies there was a steady rise during the first week. The ratio of HVA to VMA output was higher in these infants than in adults, suggesting a more rapid turnover of dopamine than adrenaline and noradrenaline. Unlike adult values, both HVA and VMA excretion values were directly related to urine volume, an observation perhaps related to renal immaturity. An unexplained reduction in HVA output in jaundiced as opposed to nonjaundiced infants was observed in the first 2 days of life. The ratio of 4-hydroxy-3-methoxyphenylglycol to VMA was about the same as in the adult. p-Hydroxyphenyl-lactic acid (p-HPLA), because of its superior stability, was measured in preference to p-hydroxyphenylpyruvic acid as an index of tyrosyluria. An output of 1 mg p-HPLA/24 h is proposed as the upper limit of normal. Prematurity was associated with a significant rise in p-HPLA output. A dramatic increase in excretion of this acid was noted in jaundiced, compared with nonjaundiced infants, presumably a manifestation of general enzyme immaturity.
 ...
PMID:Urinary phenolic acid and alcohol excretion in the newborn. 120 Jun 75

Twelve-hour urinary excretion of 4-hydroxy-3-methoxymandelic acid (VMA), homovanillic acid (HVA), and 3-methoxy-4-hydroxyphenylglycol (MHPG) was studied in 20 premature infants, 8 without apnea and 12 with apnea. All infants were studied at 1-3 days of postnatal age (before apnea). Nonapneic infants were restudied at 10-15 days of postnatal age. Apneic infants were also restudied 24 h after apnea. Apnea was not associated with decreased urinary excretion of VMA and MHPG. Only HVA, when expressed as microgram/kg body weight, was significantly lower after the onset of apnea. This difference disappeared when HVA was expressed as microgram/mg creatinine. We suggest that apnea of prematurity may not be related to the immaturity of catecholamine pathways.
 ...
PMID:Study of neurotransmitters in premature infants with or without apnea of prematurity. 613 Aug 40