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Attention deficit disorders: a study of peptide-containing urinary complexes
K Hole1, O Lingjaerde, L Mørkrid
1Department of Physiology, University of Bergen, Norway.
Insights
Urinary peptide patterns differ in children with attention deficit disorder (ADD). Specific complex variations may help diagnose ADD with or without hyperactivity, offering potential biochemical markers.
Area of Science:
- Biochemistry
- Neuroscience
- Pediatrics
Background:
- Abnormal urinary peptide and protein-associated peptide complexes are observed in behavioral disorders.
- Gel filtration patterns of these urinary substances show disorder-specific characteristics.
Purpose of the Study:
- To investigate urinary peptide-containing complexes in children diagnosed with attention deficit disorder (ADD), with or without hyperactivity.
- To identify potential biochemical markers for differentiating ADD subtypes.
Main Methods:
- Gel filtration analysis of urinary precipitates from 104 children (91 boys, 13 girls) with ADD and 36 healthy controls.
- Clinical, neuropsychological, and psychophysiological assessments for patient selection.
- Purification and functional analysis of a specific urinary peptide fraction from hyperactive patients.
Main Results:
- Urinary gel filtration patterns in ADD patients differed significantly from controls.
- Increased benzoic acid-glycoprotein-peptide complexes were found in 64 patients with attention deficit disorder with hyperactivity (ADDH).
- Reduced uric acid complexes were observed in 35 patients, primarily those with ADD without hyperactivity.
- A purified peptide fraction from hyperactive patients enhanced platelet uptake of 14C[5-HT].
Conclusions:
- Urinary peptide complex patterns show promise as potential diagnostic biomarkers for attention deficit disorder subtypes.
- Further research is warranted to validate these findings for clinical diagnostic applications.
- Biochemical analysis of urinary peptides may aid in the diagnosis of behavioral disorders like ADD.
Abstract:
In several behavioral disorders, we have observed that abnormal amounts of peptides and protein-associated peptide complexes are excreted in the urine. The gel filtration patterns of these excreted substances have some specificity for the different disorders. The urinary excretion of peptide-containing complexes was studied in 91 boys and 13 girls (mean age 9.4 years, range 1-23) with the clinical diagnosis of attention deficit disorder (ADD), with or without hyperactivity. The gel filtration of urine precipitate showed patterns in all patients that were different from those seen in 36 normal controls. Sixty-four patients had increased benzoic acid-glycoprotein-peptide complexes in the late peaks. The symptoms of all these patients fit the criteria for diagnosis of attention deficit disorder with hyperactivity (ADDH). Thirty-five patients showed reduced amounts of uric acid complexes in the late peaks. Clinically, this group, with the exception of three patients, fit the criteria for diagnosis of attention deficit disorder without hyperactivity. Five patients showed reduced amounts of all urinary complexes; four of these were hyperactive. Moderate exercise in control children did not change the urinary pattern. One urinary peptide fraction from hyperactive patients, purified to homogeneity, increased the uptake of 14C[5-HT] in platelets. Strict clinical, neuropsychological, and psychophysiological selection of the patients reduced the heterogeneity of the patterns. Although more studies are needed, the findings seem promising for the possibility of developing biochemical tests that may be helpful diagnostically.