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  • 1
    ISSN: 1432-1076
    Keywords: Phenylketonuria ; Selective ; sustained attention ; Impaired frontal lobe functions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Twenty normally intelligent children with early treated phenylketonuria (PKU) (IQ: mean=101.4, SD=10.0; age: mean=10 years 11 months, SD=1.3 years) and 20 healthy controls, matched for age, sex and IQ, were assessed for their selective (Stroop Task) and sustained attention (Test-d-2). Using positron emission tomography an activation of the frontal lobe during the Stroop task had previously been demonstrated. In addition to the Stroop Task and the Test-d-2, a short-term memory test as a “non-frontal-lobe-function-task” was administered to all subjects. Group comparisons demonstrated that PKU children had specific deficits in selective and sustained attention, which were significantly correlated with the concurrent serum phenylalanine concentration. Conclusion The results give evidence that even dietary treated children with PKU were suffering from impaired attentional control mechanisms in spite of a normal IQ. The deficits might be the result of impaired frontal lobe functions.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1076
    Keywords: Key words Phenylketonuria ; l-dopa therapy ; Neuropsychological tests
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Eight adult, untreated patients with classical phenylketonuria received L-dopa and a decarboxylase inhibitor for 2 weeks. No effect of l-dopa therapy on choice reaction time tasks, sustained attention, frontal lobal function as well as latencies of visual evoked potentials was found. The results raise the question if adult patients with phenylketonuria really suffer from functional dopamine deficiency.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-1076
    Keywords: Key words Phenylketonuria ; Positron emission tomography ; Dopamine D2-receptor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Patients with phenylketonuria (PKU) may suffer from cognitive and neurological deficits which are related to reduced intracerebral concentrations of catecholamines. The function of phenylalanine (Phe) as an inhibitor of the uptake of the precursor amino acid tyrosine (Tyr) through the blood-brain barrier as well as an inhibitor of the expression of dopamine receptors in the brain is under investigation. Positron emission tomography (PET) is a method for quantitatively determining biochemical and physiological processes in vivo. In the current pilot study, l-[1-11C]-Tyr and 18F-fluoro-ethyl-spiperone (FESP) have been used. The metabolic pathway of carboxylic labelled Tyr is mainly incorporation into protein. From the measured tissue and plasma activity as a function of time in combination with a compartimental model the Protein Synthesis Rate (PSR) for Tyr can be calculated. FESP is a ligand which binds irreversibly to the dopamine D2-receptor and has also a low non specific binding, although affinity to the serotonin receptor has been described. The ratio of FESP concentration in striatum and in cerebellum is a measure of the receptor status in vivo. In patients with plasma Phe levels above the maximum therapeutic concentration (〉 700 μmol/l) the PSR for Tyr was decreased as compared to controls and patients with plasma Phe concentrations within the therapeutic range, indicating a decreased availability of Tyr for neurotransmitter synthesis, and hence explaining the reduced cerebral concentration of catecholamines.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    European journal of pediatrics 155 (1996), S. S101 
    ISSN: 1432-1076
    Keywords: Key words Phenylketonuria ; Psychological characteristics ; Social ; findings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Psychosocial aspects in phenylketonuric (PKU) patients are reported. In two separate studies patients with PKU differing in age (children versus adolescents), were assessed. The main message of the first prospective study on 58 10-year-old patients is that normally intelligent PKU patients who were treated early and strictly did not show a higher risk for severe emotional and behavioural maladjustment compared with healthy controls at the age of 10 years. The data were obtained in the course of the German PKU Collaborative Study by the “Personality Questionnaire for Children (PFK 9–14)”. All patients received nutritional, medical, and psychological counselling every 6 months. In the second retrospective study, 34 early treated, normally intelligent adolescents with PKU (age: mean = 14.6, SD = 2.0, range = 11–18 years) and their mothers were assessed with several psychometric personality inventories and self-developed questionnaires concerning their psychosocial situation and their disease- and diet-specific knowledge. Using the Mannheimer Biographic Inventory (MBI), the Personality Questionnaire for Children (PFK 9–14), and the Freiburger Personality Inventory (FPI) the adolescent patients described their social life and their emotional development as being distinctly restricted. Their knowledge concerning disease and diet was alarmingly poor and the majority had great difficulties in satisfactory dietetic management without parental help. In addition to the burdensome diet, developmental crises like puberty may cause more frequently emotional and behavioural problems in PKU patients.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-1076
    Keywords: Key words Phenylketonuria ; Non-PKU HPA ; intellectual and neurological outcome
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The intellectual, neurological, and neuropsychological outcome of patients with non-phenylketonuric-hyperphenylalaninaemia (PKU-HPA) (serum phenylalanine levels under free diet 〈 600 μmol/l) has not been systematically studied so far. We therefore tested 28 patients (mean age = 21.8, SD = 4.2 years) for IQ (WAIS-R/WISC-R), school performance, job career, clinical neurological examination, fine motor performance (motor performance task), and selective and sustained attention (stroop task, Dot Pattern Exercise from the Sonneville visual attention task). In addition, cranial MRI (1.5 T unit) was obtained in 10 of these patients. Clinical-neurological examination revealed no significant abnormalities in the non-PKU-HPA patients. They also had a normal IQ (mean = 101.9, SD = 13.6). Compared to their healthy siblings, they attended a normal school and had a normal job career. The motor performance task revealed no deficits in fine motor abilities. The patients performed normally in the stroop task and the dot pattern exercise. Their MRIs were normal. Our results indicate that patients with non-PKU-HPA are not at risk for developing intellectual, neurological, and neuropsychological impairment, as described for patients with treated mild or classical phenylketonuria. From this point of view a dietary treatment is not necessary in patients with hyperphenylalaninaemia.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    European journal of pediatrics 155 (1996), S. S64 
    ISSN: 1432-1076
    Keywords: Key words Hyperphenylaninaemia ; Phenylketonuria ; Evoked potentials ; Metabolic disorders ; Dopamine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We performed studies of multimodal evoked potentials and peripheral sensory and motor nerve conductions in 33 early and 6 late treated patients with phenylketonuria. The studies revealed the following picture: 1. In 27% of early treated patients latencies of visual evoked potentials were increased. The cause for these changes is unknown. 2. Nerve conduction studies showed the presence of a minor sensory neuropathy which in rare cases may also affect peripheral motor nerves. This neuropathy did not have features of a central-peripheral distal axonopathy which argues against a toxic/nutritional causation. 3. Deficits in the central sensory, motor, and auditory pathways were present, but rare in early treated patients. If the results of electrophysiological studies reported by different groups are compared, the emerging picture is very similar and the majority of the – minor – differences is likely to be explained by technical aspects.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    European journal of pediatrics 155 (1996), S. S173 
    ISSN: 1432-1076
    Keywords: Key words Phenylketonuria ; Maternal phenylketonuria ; Phenylalanine ; Pregnancy outcome ; Phenylalanine restricted diet
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The German maternal phenylketonuria (MPKU) Study began in 1989 and since 1992 works together with the American-Canadian MPKU Study. Main goals of the study are: (1) to find women with phenylketonuria (PKU) and mild untreated hyperphenylalaninaemia (HPA); (2) to inform them about the risks of an untreated pregnancy with PKU and HPA; (3) to evaluate the efficacy of the phenylalanine (Phe) restricted dietary treatment prior to and during pregnancy by following the physical and cognitive development of offspring from treated pregnancies. An interim report of the study is presented. Until now, 43 pregnancies have been followed. They resulted in 34 live births, 24 from women with PKU and 10 from women with HPA. There are significant negative correlations between the gestational age in which the dietary control (blood Phe level 〈 360 μmol/l) was reached and pregnancy outcome as measured by growth parameters and early cognitive and motor developmental quotients at the age of 2 years. For minimizing risks of MPKU, preconceptional dietary control is strongly recommended. Tracking and timely information of young women about risks of MPKU is of outmost importance.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-1076
    Keywords: Key words Phenylketonuria ; Hyperphenylalaninaemia ; Phenylalanine levels ; Treatment recommendations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Treatment of hyperphenylalaninaemias due to phenylalanine hydroxylase deficiency with a low phenylalanine (Phe) diet is highly successful in preventing neurological impairment and mental retardation. There is consensus that, for an optimal outcome, treatment should start as early as possible, and that strict blood Phe level control is of primary importance during the first years of life, but for adolescent and adult patients international treatment recommendations show a great variability. A working party of the German Working Group for Metabolic Diseases has evaluated research results on IQ data, speech development, behavioural problems, educational progress, neuropsychological results, electroencephalography, magnetic resonance imaging, and clinical neurology. Based on the actual knowledge, recommendations were formulated with regard to indication of treatment, differential diagnosis, and Phe level control during different age periods. The development of the early-and-strictly-treated patient in middle and late adulthood still remains to be investigated. Therefore, the recommendations should be regarded as provisional and subject to future research. Efficient treatment of phenylketonuria has to go beyond recommendations for blood Phe level control and must include adequate dietary training, medical as well as psychological counselling of the patient and his family, and a protocol for monitoring outcome. Conclusions Early-and-strictly-treated patients with phenylketonuria show an almost normal development. During the first 10 years treatment should aim at blood Phenyl-alanine levels between 40 and 240 μmol/L. After the age of 10, blood phenylalanine level control can be gradually relaxed. For reasons of possible unknown late sequelae, all patients should be followed up life-long.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-1076
    Keywords: Key words Bone tumours in children ; Plasminogen activators ; LMWH
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To evaluate the role of fibrinolytic and proteolytic proteins in children and adolescents suffering from Ewing sarcoma or osteosarcoma with respect to postoperative complications and late outcome, a prospective two-arm two-centre study was conducted. Plasminogen, plasminogen activator inhibitor (PAI)-1, tissue-type plasminogen activator (t-PA) and urokinase plasminogen activator (u-PA) were investigated in the pre-surgical period and in the postoperative follow-up period in children suffering from Ewing sarcoma (ES; n = 36) or osteosarcoma (OS; n = 39). In addition, the factor V mutation (FV) Q506, protein C, protein S, antithrombin and lipoprotein (a) were determined. All children received LMWH (EnoxaparinR) 1 mg/kg sc. once daily over a period of 6 weeks to 3 months. Besides a short-lasting increase of PAI-1 in patients with OS on day 1 and in children with Es on day 14, a small and significant but clinically irrelevant difference was found on days 7–10 for plasminogen, t-PA and u-PA. No thromboembolic complications occurred in patients treated with LMWH and having a prothrombotic genetic risk factor. Within one year of surgery 7 out of 36 patients with ES and 5 out of 39 children with OS showed a relapse of their disease. Prior to the first local tumour therapy, 5 out of 7 children with ES and relapse had elevated u-PA concentrations compared with 2 out of 5 children in the OS group. No such differences were found for PAI-1- or t-PA antigen. Conclusion The role of u-PA as a possible follow-up marker for a poorer outcome in children with ES should be evaluated in a prospective multicentre study.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-1076
    Keywords: Key words Homocystinuria ; Excitotoxicity ; Organotypic cultures ; Xenopus oocytes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The excitotoxic action of homocysteine and related sulphur-containing metabolites was investigated in organotpyic cultures derived from rat brain cortex and hippocampus by inhibition experiments using antagonists selective for different glutamate receptor subtypes. In addition the direct interaction of these metabolites with glutamate receptors expressed in frog oocytes was tested by conventional two electrode voltage clamp techniques. Conclusion Neurodegeneration and epilepsy observed in homocystinuria may be mediated by l-homocysteic and l-homocysteine sulphinic acid. Both metabolites exhibit excitotoxic potency by interaction with different glutamate receptor subtypes.
    Type of Medium: Electronic Resource
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