Biomedical subjects

Henrik Uebel

Publications and source records attributed to Henrik Uebel.

4 recordsLinked to original sources

PubMed2006

Serum level of semicarbazide-sensitive amine oxidase in children with ADHD.

BACKGROUND: The objective of this study was to analyze the extracellularly acting semicarbazide-sensitive amine oxidase (SSAO) serum levels in children with ADHD for the first time. SSAO is known to show deviations from normal in various somatic disorders and to interplay with the intracellularly active MAO. In humans two forms of SSAO a circulating form in plasma and a membrane-bound form are involved in monoaminergic metabolism. METHODS: We analyzed serum levels of SSAO in 27 children meeting ICD-10 criteria of Hyperkinetic Disorder (F90) or DSM-IV criteria of ADHD combined type by HPLC method and fluorimetric detection. A group of 42 healthy volunteers within the same age range (7.0 - 14.0 years) served as controls. RESULTS: No significant differences between children with ADHD (SSAO activity M = 773, SD = 217 mU/l) and healthy controls (SSAO activity M = 775, SD = 256 mU/l) in SSAO serum levels were found (F = 2.18; p > 0.14). Further, stimulant medication status had no influence on the result (F = 2.52; p > 0.11). CONCLUSION: There is no evidence for a deviation of SSAO serum activity in ADHD. Hence, extracellularly acting SSAO does not seem to be a promising factor for further research in ADHD. But progress in knowledge of its physiologic role and of the relationship between the membrane-bound and the circulating serum form may open new avenues for research on SSAO in ADHD.

Journal Article↗

PubMed2006

Colour perception in ADHD.

Attention-deficit/hyperactivity disorder (ADHD) is associated with unexplained impairments on speeded naming of coloured stimuli. These deficits may reflect hypofunctioning retinal dopaminergic mechanisms impairing particularly blue-yellow colour discrimination. Colour perception and rapid colour naming ability were investigated in 14 children with ADHD and 13 healthy peers matched for age, gender, and IQ, using the Farnsworth-Munsell 100 Hue Test (FMT) and the Stroop-Colour-Word test. Children with ADHD committed more errors on the FMT, particularly on discrimination of colours along the blue-yellow axis, and were slower on Stroop subtests involving colour naming. However, the latter deficit was accounted for similarly by blue-yellow and red-green discrimination abilities. Blue-yellow colour perception problems in ADHD contribute to but do not fully explain the observed slowed colour naming.

Adolescent↗

PubMed2004

Neuronal network models of ADHD -- lateralization with respect to interhemispheric connectivity reconsidered.

BACKGROUND: Recent research on structural and functional anatomy related to ADHD has concentrated on fronto-striatocerebellar circuits. These findings and resultant neurobiological models of ADHD may explain some of the disturbances. On the other hand, there is some evidence that the restricted look at anterior-posterior anomalies might neglect the important additional information of lateralization problems related to hemispheric connectivity. OBJECTIVE: Hence, the role of lateralization in the pathophysiology of ADHD should be reconsidered. METHOD: After a short review of imaging studies in ADHD the special role of the corpus callosum (including the influence of its anomalies on general brain development, lateralization and functioning) is outlined and the first case of total agenesis of corpus callosum in a child with ADHD is presented and discussed within this context. CONCLUSIONS: In view of the remaining inconsistencies concerning structural and functional brain anomalies in ADHD, attention should be paid not only to anterior- posterior but also to left-right aspects of functional and structural brain anomalies. This should include disturbances probably related to anomalies of the corpus callosum, especially in regard to co-existing problems like dyslexia and developmental coordination disorder.

Agenesis of Corpus Callosum↗

PubMed2004

Comparative efficacy of once-a-day extended-release methylphenidate, two-times-daily immediate-release methylphenidate, and placebo in a laboratory school setting.

BACKGROUND: Given the dosing limitations of methylphenidate short-acting preparations in treating ADHD, galenics with longer release of the substance were developed mainly to avoid drug intake during school hours. OBJECTIVES: This investigation was conducted to assess the efficacy and the duration of action of a new extended-release formulation of methylphenidate (Medikinet retard) as a once-daily treatment for children with attention-deficit hyperactivity disorder (ADHD). METHOD: This was a randomized, double-blind, crossover multicentre study with three treatment conditions: once-daily extended-release methylphenidate, twice-daily immediate-release methylphenidate and placebo given to 79 children (8-14 years old) with ADHD. Daily assessments in an analogue classroom setting included blind ratings of attention and deportment and a performance measure (math test) obtained 5 times over an 8-hour period. Secondary measures included an ADHD rating scale, based on DSMIV/ ICD-10 separately rated for the morning and the afternoon. RESULTS: Both active treatment conditions displayed significant time course effects and were superior to placebo in improving all efficacy measures. Once a day extended-release methylphenidate was not different from the same dose of twice daily immediate-release methylphenidate. CONCLUSIONS: These data provide support for the benefit of this novel, once-daily methylphenidate preparation in the treatment of ADHD. The longer duration of action of Medikinet Retard has the potential to simplify psychostimulant treatment, thus reducing dose diversion and eliminating the need for in-school administration.

Adolescent↗