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  • Organic Chemistry  (27)
  • General Chemistry  (17)
  • Inorganic Chemistry  (16)
  • Phenylketonuria  (4)
  • 1
    ISSN: 1432-1076
    Keywords: CNS development ; Dietary treatment ; EEG ; IQ ; Phenylketonuria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In 34 children with phenylketonuria (PKU) treated early the prognostic value of the age on institution of the diet (within the first 3 months of life) and of the quality of dietary treatment was determined in two different ways: 1) following intelligence closely (IQ) and (2) evaluating the EEG development up to their 12th (n=34) and 15th (n=18) years of life as appropriate. In general, IQ scores were found to be normal from the 4th–15th years of life. In our group of patients there was no effect on the IQ of the timing of diet onset. Children with “strict” dietary control showed a significantly higher IQ than those with “loose” control. One hundred and fifty-four EEGs (10/20 system, awake with eyes closed) were recorded at intervals of 2 years and conventionally evaluated. The development of alpha-activity was found to be normal. Beta-activity was enhanced. Abnormal EEG findings like general slowing and generalized paroxysmal activity (GPA) with or without spikes were more frequent in children with PKU than in controls, with the exception of focal abnormalities. EEG abnormalities increased with advancing age independently of IQ development and showed no relation to either the age at the onset nor the quality of dietary treatment.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1076
    Keywords: Phenylketonuria ; Biopterin ; Phosphate-eliminating enzyme ; 6-Pyruvoyl tetrahydropterin synthase ; Amniotic fluid ; Erythrocytes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Amniocentesis was performed at 19 weeks gestation in a mother who had previously delivered a boy with “dihydrobiopterin synthetase” (DHBS) deficiency. The amniotic fluid contained neopterin in high (136 nmol/l) and biopterin in very low concentrations (1.8 nmol/l). The activity of the phosphate-eliminating enzyme (PEE, also called 6-pyruvoyl tetrahydropterin synthase, substrate: 7,8-dihydroneoptein triphosphate) which is present in liver and erythrocytes and defective in DHBS deficiency, was measured in the erythrocytes of the family members. The fetal sample showed only 2% of the activity of healthy adult controls and was comparable with that of the affected sibling. Obligate heterozygotes had activities around 20% of the controls. Two fetal control samples showed even higher activities than adult erythrocytes. Sepiapterin reductase activities were normal in all cases. At autopsy, PEE deficiency was confirmed in the liver of the fetus. We concluded that DHBS deficiency (and most probably also GTP cyclohydrolase I deficiency) can be diagnosed by metabolite measurements in amniotic fluid. PEE activity is measurable in erythrocytes, although the assay needs to be improved. Since maternal tetrahydrobiopterin does not cross the placenta, treatment of a tetrahydrobiopterin-deficient fetus with tetrahydrobiopterin in utero is not possible.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    European journal of pediatrics 157 (1998), S. 824-830 
    ISSN: 1432-1076
    Keywords: Key words Intelligence ; Neurology ; Neuropsychology ; Phenylketonuria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Due to the observation of severe neurological symptoms in single patients as well as brain imaging, neuropsychological and neurophysiological abnormalities, the long-term prognosis of treated phenylketonuria is still under discussion. We investigated the neurological outcome of 57 (24 male, 33 female) patients with phenylketonuria (diet onset 〈3 months) at a mean age of 23.6 (17–33) years in comparison to control subjects. Methods used were a clinical-neurological examination, tests for fine motor abilities, IQ test (WAIS-R), a neuropsychological attention task and MRI (30 patients only). Tremor was increased in the patients (28%) compared to controls (15%). Fine motor abilities were significantly reduced in three areas: hand-wrist steadiness, finger-hand dexterity and hand-wrist speed. Tremor as well as reduced fine motor skills were not associated with treatment-related variables, e.g. diet onset, strictness of biochemical control or amount of MRI white matter change. IQ was lower in patients (mean 97.6) compared to matched control subjects (mean 105.5). IQ at 12 years was correlated with biochemical control from birth up to the age of 12 and remained stable up to adult age, independent of biochemical control after 12 years of age. In contrast to the other outcome parameters, the performance in a neuropsychological attention task was influenced by the concurrent plasma phenylalanine concentration. Specific late-onset neurological impairment was not identified in this sample of early-treated adults with phenylketonuria. Conclusion Careful neurological investigation revealed subtle symptoms of brain damage even after early-initiated treatment in adult patients with phenylketonuria. At present it cannot be excluded that further neurological deterioration could emerge later in life. Thus, patients with phenylketonuria – either on or off diet – should be monitored throughout life.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    European journal of pediatrics 146 (1987), S. A17 
    ISSN: 1432-1076
    Keywords: Phenylketonuria ; Adolescents ; Dietary control ; Intelligence ; Psychological problems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Deactivation Behaviour of Arenes and Heteroarenes. XXXVI. The Solvent and Temperature Dependence of Deactivation Behaviour of 9, 9′-Bis(acridizinium-yl) at High ConcentrationAt room temperature the geometrical structure of the fluoresceing singlet state of 9, 9′-bis(acridizinium-yl) is determined by the solvent. In solvents of the type A (water, methanol, acetonitril) a plain S1-state emits, in the case of the solvent type B (ethanol, propanol-(2)) the S1-state is twisted. Both excited states have different emission spectroscopical properties.At high concentration (c ≥ 10-4 mol l-1) in the case of the solvent type B a new emission band is observed, and the monomer emission is quenched. This new band is interpreted as a fluorescence from a molecular associate in the excited state. The intensity of this associate band is increasing with decreasing temperature. It is shown that this band is the result of molecular association in the ground state. From the photochemical irradiation it follows that only in the case of the solvent type B a photocycloaddition is possible. The plain S1-state does not react.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 339 (1997), S. 482-484 
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On the Mass Spectrometric Characterization of ω-Chloralkylphenylphosphines
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 2 (1955), S. 196-202 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Viskosität von Lösungen des sogenannten KURROLschen Kaliumsalzes (KPO3)x ist nicht nur abhängig von den Herstellungsbedingungen, insbesondere der Temperaturführung, sowie vom genauen Molverhältnis K2O:P2O5 des Ausgangsmaterials und  -  hierdurch bedingt  -  vom Grad der Vernetzung der Polyphosphatketten, sondern auch von der Anwesenheit geringer Verunreinigungen. So läßt sich der höchstviskose Typ nur aus völlig arsenfreien Ausgangsprodukten darstellen. Arsen (V) wird in die Polyphosphatanionen eingebaut. Beim Behandeln mit Wasser hydrolysiert Arsen (V) momentan als Orthoarsenat heraus, wodurch Kettenbruch eintritt, und man erhält Lösungen von geringerer Viskosität, was schon merklich ist, wenn auf 106 Atome P 1 Atom Arsen kommt. Hieraus wird geschlossen, daß der durchschnittliche Kondensationsgrad der Polyphosphatanionen im höchstviskosen KURROLschen Kaliumsalz mindestens von der Größenordnung 106 sein muß.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 155 (1940), S. 129-162 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 313 (1971), S. 956-968 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Addition verschiedener elektrophiler Agenzien an ω-Methoxyolefine wurde untersucht, um Aufschluß über eine Methoxygruppenbeteiligung zu erhalten. Eine derartige Beteiligung konnte bei der Addition von Chlor und Brom an 5-Methoxypenten-(1) nachgewiesen werden; hier entstehen zu 10-15% die entsprechenden 2-Halogenmethyltetrahydrofurane, und zu 50-60% tritt Umlagerung unter Verschiebung der Methoxygruppe ein. Die Addition von Chlor oder Brom an 6-Methoxyhexen-(1) liefert zu 15-20% die entsprechenden 2-Halogenmethyltetrahydropyrane, eine Methoxylgruppenwanderung ist nicht nachweisbar. Die Reaktion von Chlor oder Brom mit 4-Methoxybuten-(1) und mit 7-Methoxyhepten-(1) liefert ausschließlich 1, 2-Additionsprodukte.Bei der Anlagerung von Chlor an Allyl-methyl-äther erhält man außer 73% 2,3-Dichlor-1-methoxypropan infolge nebenher ablaufender Dreikomponentenreaktionen 12% 1,2,3-Trichlorpropan, 7% 1,3-Dimethoxy-2-chlorpropan und 8% 1, 2-Dimethoxy-3-chlorpropan. Bei der Addition von 2,4-Dinitrophenylsulfenylchlorid und von Quecksilberacetat an ω-Methoxyolefine tritt weder Umlagerung noch Ringschluß ein. Mit 2, 4-Dinitrophenylsulfenylchlorid entstehen nebeneinander Markownikow- und anti-Markownikow-Produkte, der Anteil des Markownikow-Produktes steigt mit wachsender Kettenlänge vom Allyl-methyl-äther bis zum 7-Methoxyhepten-(1).
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 312 (1970), S. 622-634 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Elektrophile Additionen an Cyclooctadien-(1,5) können unter transannularer Beteiligung der zweiten Doppelbindung zu Bicylo [3,3,0] octanderivaten führen. Diese entstehen allerdings nur, wenn starke Protonsäuren, starke Lewis-Säuren oder Chlor als elektrophile Agenzien angewandt werden.Elektrophile Additionen in Methanol oder in Essigsäure als Lösungsmittel führen im ersten Reaktionsschritt vorzugsweise zu nicht umgelagerten Dreikomponentenprodukten; der elektrophile Angriff auf die zweite Doppelbindung erfolgt dann unter transannularer Beteiligung der OMe- oder OAc-Gruppe und führt zu Gemischen aus 9-Oxa-bicyclo[3,3,1]-nonan- und 9-Oxa-bicyclo[4,2,1]nonan-Derivaten.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
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