Related Experiment Video

Updated: Aug 12, 2026

Biochemical Measurement of Neonatal Hypoxia
13:13

Biochemical Measurement of Neonatal Hypoxia

Published on: August 24, 2011

Factors determining blood phenylalanine in the neonatal period

D Burman, J B Holton, A F Morris

    Clinica Chimica Acta; International Journal of Clinical Chemistry
    |July 23, 1975
    PubMed

    Insights

    Blood phenylalanine levels are higher in low birth weight infants and increase with age. Urban infants also showed higher levels, with no significant sex-based differences observed in this large infant study.

    Area of Science:

    • Biochemistry
    • Pediatrics
    • Neonatology

    Background:

    • Blood phenylalanine levels are a key indicator in infant health.
    • Understanding factors influencing these levels is crucial for early detection of metabolic disorders.
    • Birth weight, age, sex, and geographic location are potential influencing factors.

    Purpose of the Study:

    • To investigate the impact of age, sex, birth weight, and area of birth on blood phenylalanine levels in a large infant cohort.
    • To identify specific demographic and environmental factors associated with altered phenylalanine concentrations.

    Main Methods:

    • Analysis of blood phenylalanine levels in 41,795 infants.
    • Stratification of data based on infant age, sex, birth weight (low vs. normal), and area of birth (urban vs. rural).

    Main Results:

    • Infants with low birth weight exhibited higher mean phenylalanine levels compared to normal birth weight infants up to 43 days of age.
    • A consistent trend of increasing blood phenylalanine with advancing age was observed in both birth weight categories.
    • No significant sex-based differences in phenylalanine levels were found.
    • Infants residing in urban areas showed significantly higher blood phenylalanine levels than those in rural areas across several age and birth weight groups.

    Conclusions:

    • Birth weight and age are significant determinants of blood phenylalanine levels in infants.
    • Environmental factors, specifically urban living, may be associated with elevated phenylalanine levels.
    • Further research is warranted to explore the mechanisms behind these observed differences and their clinical implications.

    More Related Videos

    Assessment and Evaluation of the High Risk Neonate: The NICU Network Neurobehavioral Scale19:15

    Assessment and Evaluation of the High Risk Neonate: The NICU Network Neurobehavioral Scale

    Published on: August 25, 2014

    In Vivo Real-Time Study of Drug Effects on Carotid Blood Flow in the Ovine Fetus11:59

    In Vivo Real-Time Study of Drug Effects on Carotid Blood Flow in the Ovine Fetus

    Published on: April 28, 2023

    Related Concept Videos

    Background and Environment Affect Phenotype02:27

    Background and Environment Affect Phenotype

    Although the genetic makeup of an organism plays a major role in determining the phenotype, there are also several environmental factors, such as temperature, oxygen availability, presence of mutagens, that can alter an organism’s phenotype.
    An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...
    Inborn Errors of Metabolism01:20

    Inborn Errors of Metabolism

    Phenylketonuria (PKU) is a protein metabolism disorder characterized by high blood levels of the amino acid phenylalanine. This results from a mutation in the gene responsible for phenylalanine hydroxylase, an enzyme that converts phenylalanine into tyrosine. When this enzyme is deficient, phenylalanine builds up in the blood, leading to symptoms such as vomiting, rashes, seizures, growth deficiency, and severe mental retardation. An early diagnosis and a diet restricting phenylalanine intake...
    Factors Affecting Protein-Drug Binding: Patient-Related Factors01:29

    Factors Affecting Protein-Drug Binding: Patient-Related Factors

    Protein-drug binding, a pivotal aspect of pharmacokinetics, is subject to considerable variability influenced by an array of patient-related factors. The intricate interplay of age, individual differences, and pathological conditions significantly impact the binding dynamics and subsequent pharmacological effects.
    Age stands as a key determinant in protein-drug binding. Neonates, characterized by low albumin content, experience heightened concentrations of unbound drugs such as phenytoin and...
    Pharmacokinetics in Pediatric Patients: Overview and Drug Absorption01:23

    Pharmacokinetics in Pediatric Patients: Overview and Drug Absorption

    Understanding the physiological differences in the pediatric population is crucial for effective pharmacotherapy. Neonates, infants, and children exhibit significant variations in gastric pH, gastric emptying time, intestinal transit time, and biliary function. These variations profoundly affect oral drug absorption, necessitating a nuanced approach to pediatric dosing.Neonates present with a unique physiological profile, having a gastric pH greater than 4 and faster and more irregular gastric...
    Pharmacokinetics in Pediatric Patients: Drug Distribution01:17

    Pharmacokinetics in Pediatric Patients: Drug Distribution

    Drug distribution in the pediatric population exhibits unique challenges and considerations due to the physiological differences between children, particularly neonates and infants, and adults. A crucial aspect of pediatric pharmacology is understanding how these differences impact the pharmacokinetics of various drugs, necessitating age-specific dosing strategies to ensure efficacy and safety.Neonates and infants have a higher total body water content, ~75%–90% of their body weight, compared...
    Pharmacokinetics in Pediatric Patients: Drug Metabolism01:24

    Pharmacokinetics in Pediatric Patients: Drug Metabolism

    In pediatric care, understanding the nuances of hepatic drug metabolism is crucial, as it significantly differs from that of adults. This divergence is primarily due to the developmental stage of drug-metabolizing enzymes, which affects how medications are processed in the body. In neonates, for instance, the activity of Phase I enzymes—critical for the initial breakdown of drugs—is markedly reduced, functioning at just 20–40% of the levels seen in adults. This reduction poses a challenge in...