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  • 1
    Electronic Resource
    Electronic Resource
    Selenium requirements in patients with inborn errors of amino acid metabolism and selenium deficiency (1980)
    Springer
    European journal of pediatrics 134 (1980), S. 65-68 
    Details
    ISSN: 1432-1076
    Keywords: Selenium ; Glutathione peroxidase ; Selenium deficiency ; Selenium supplementation ; Nutrition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The diets of 5 patients with phenylketonuria or maple-syrup-urine disease were supplemented with yeast which was rich in selenium. For 120 days the patients received 45 μg Se/day to increase the Se content of their diets to 10–12ng Se/Kjoule. Before supplementation the selenium content of serum (5–15 ng/ml) and whole blood (10–27 ng/ml), and the activity of the erythrocyte glutathione peroxidase (0.19–2.69 U37/g Hb), amounted to only 10–20% of normal. The serum selenium content reached normal values within 4 weeks of supplementation, followed by normalisation of the selenium content of whole blood within 4–8 weeks. Restoration of the activity of erythrocyte glutathione peroxidase took 9 to 15 weeks —the red cell life span. There was a significant positive correlation between the selenium content of the erythrocytes and the activity of erythrocyte glutathione peroxidase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00442405
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  • 2
    Electronic Resource
    Electronic Resource
    Plasma glutathione peroxidase after selenium supplementation in patients with reduced selenium state (1982)
    Springer
    European journal of pediatrics 138 (1982), S. 138-140 
    Details
    ISSN: 1432-1076
    Keywords: Selenium ; Supplementation ; Plasma ; Glutathione peroxidase ; Glutathione S-transferase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The plasma glutathione peroxidase (GSHPx) activity was measured in normal adults and children and in patients with reduced selenium state because of dietary treatment of metabolic diseases (phenylketonuria or maple-syrup-urine disease) before and after selenium supplementation. Besides GSHPx (measured with t-butyl hydroperoxide, cumene hydroperoxide and hydrogen peroxide as acceptor substrates) the activity of glutathione S-transferase was estimated in plasma. Plasma GSHPx activity in healthy children was significantly lower than in healthy adults. In 11 dietetically treated patients with phenylketonuria or maple-syrup-urine disease the plasma GSHPx was reduced to about 17% of the values of healthy children of the same age. No glutathione S-transferase activity could be found in plasma of children in normal or reduced Se state. During administration of yeast rich in Se (200μg Se/d) for 90 days 2 healthy adults showed no significant change of plasma GSHPx activity. During Se supplementation (75–100μg Se/d) for 120–163 days 5 dietetically treated patients with PKU or MSUD exhibited a significant increase of plasma GSHPx activity within 2 days. The values reached a plateau after 1 to 3 weeks of supplementation and remained at this level within the following 4 to 5 months. Therefore, the activity of plasma glutathione peroxidase can be used as an indicator of short-term changes of selenium intake in selenium deficient individuals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00441140
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  • 3
    Electronic Resource
    Electronic Resource
    The selenium state of healthy children (1977)
    Springer
    European journal of pediatrics 125 (1977), S. 81-88 
    Details
    ISSN: 1432-1076
    Keywords: Selenium ; Glutathione peroxidase ; Normal values ; Blood ; Infants ; Children ; Milk ; Nutrition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The selenium concentration of serum is age-dependent. The median value at birth ( $$\tilde x$$ =50×10−9g/ml) amounts to half of the median value of adults ( $$\tilde x$$ =102×10−9g/ml). After a decrease in early infancy to $$\tilde x$$ =34×10−9g/ml it steadily increases to $$\tilde x$$ =58×10−9g/ml in the second half of the first year, to $$\tilde x$$ =82×10−9g/ml in 1–5 year old children, and to $$\tilde x$$ =92×10−9g/ml in school children. The activities of the selenium containing enzyme glutathione peroxidase of erythrocytes are also reduced in early infancy (x=7.2±0.36 U37/g Hb), whereas the enzyme activities of cord blood erythrocytes (x=8.72±0.76 U37/g Hb) are in the same range as those of older children or adults. The selenium content of some commercially available milk formulas for infants are lower than those of human and cow's milk.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00470608
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  • 4
    Electronic Resource
    Electronic Resource
    Atypical vitamin B12-unresponsive methylmalonic aciduria in a sibship with severe progressive encephalomyelopathy: a new genetic disease? (1996)
    Springer
    European journal of pediatrics 155 (1996), S. 398-403 
    Details
    ISSN: 1432-1076
    Keywords: Key words Methylmalonic ; aciduria ; Vitamin B12 ; GABA ; Cerebrospinal fluid ; Encephalomyelopathy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We report on two siblings, a girl of 7 years and a boy of 2 years, who presented in infancy with hypotonia, athetoid movements, myopathy and severe developmental delay. The progressive clinical course was characterized by ophthalmoplegia, pyramidal tract signs, loss of visual contact and failure to thrive. The older sister died at the age of 7 years. The younger brother followed an almost identical clinical course. MRI of the brain revealed bilateral hypodensities and atrophy of the putamen. Neurophysiological investigations were consistent with peripheral neuropathy. Investigations for neurometabolic disorders in urine, plasma and CSF of both patients revealed a consistent increase of methylmalonic acid in urine, plasma and CSF as well as borderline low free GABA in CSF. Except for an inconstant elevation of lactate in the boy, metabolic acidosis, hypoglycaemia, episodic ketoacidosis, or hyperammonaemia, the usual concomitants of organoacidopathies, were absent in both children. Homocystinuria was excluded. Methylmalonic aciduria did not respond to antibiotic treatment, vitamin B12 therapy nor dietary protein restriction. Incorporation of [14C]propionate into protein in cultured fibroblasts was pathologically but inconsistently decreased. Both patients’ cell lines showed only minimal response to hydroxocobalamin and normal methylmalonyl-CoA mutase activity. Conclusion Even though the definitive underlying enzymatic defect in this sibship remains obscure our results suggest a new genetic disorder. This report illustrates that hitherto undescribed metabolic disorders remain to be elucidated even in long investigated areas of intermediary metabolism such as methylmalonic aciduria.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01955272
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  • 5
    Electronic Resource
    Electronic Resource
    Atypical vitamin B12-unresponsive methylmalonic aciduria in a sibship with severe progressive encephalomyelopathy: A new genetic disease? (1996)
    Springer
    European journal of pediatrics 155 (1996), S. 398-403 
    Details
    ISSN: 1432-1076
    Keywords: Methylmalonic aciduria ; Vitamin B12 ; GABA ; Cerebrospinal fluid ; Encephalomyelopathy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We report on two siblings, a girl of 7 years and a boy of 2 years, who presented in infancy with hypotonia, athetoid movements, myopathy and severe developmental delay. The progressive clinical course was characterized by ophthalmoplegia, pyramidal tract signs, loss of visual contanct and failure to thrive. The older sister died at the age of 7 years. The younger brother followed an almost identical clinical course. MRI of the brain revealed bilateral hypodensities and atrophy of the putamen. Neurophysiological investigations were consistent with peripheral neuropathy. Investigations for neurometabolic disorders in urine, plasma and CSF of both patients revealed a consistent increase of methylmalonic acid in urine, plasma and CSF as well as borderline low free GABA in CSF. Except for an inconstant elevation of lactate in the boy, metabolic acidosis, hypoglycaemia, episodic ketoacidosis, or hyperammonaemia, the usual concomitants of organoacidopathies, were absent in both children. Homocystinuria was excluded. Methylmalonic aciduria did not respond to antibiotic treatment, vitamin B12 therapy nor dietary protein restriction. Incorporation of [14C]propionate into protein in cultured fibroblasts was pathologically but inconsistently decreased. Both patients' cell lines showed only minimal response to hydroxocobalamin and normal methylmalonyl-CoA mutase activity. Conclusion Even though the definitive undorlying enzymatic defect in this sibship remains obscure our results suggest a new genetic disorder. This report illustrates that hitherto undescribed metabolic disorders remain to be elucidated even in long investigated areas of intermediary metabolism such as methylmalonic aciduria.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01955272
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  • 6
    Electronic Resource
    Electronic Resource
    Beeinflussung der katalytischen Eigenschaften von Al2O3—SiO2-Katalysatoren durch Alkalivergiftung (1974)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 403 (1974), S. 72-80 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Effect of Alkali Contamination on the Catalytic Properties of Al2O3—Si2Catalytic properties of amorphous Al2O3—SiO2 catalysts containing different amounts of Al2O3 in dehydration of isopropanol and cracking of cumene were examined after a defined contamination of the acid centers by sodium ethylate from alcoholic solution. In both reactions, the catalytic activity is decreased by treatment with sodium ethylate, the cracking of cumene being suppressed at a lower alkali concentration than the dehydration of isopropanol. In dehydration of isopropanol, the dependence of the catalytic activity on the alkali content is influenced strongly by the Al2O3 content of the catalysts. In the cracking of cumene, strongly acid Brönsted centers are active, whereas the dehydration of isopropanol proceeds by joint action of acid Lewis or Brönsted centers, respectively, with basic centers at the surface of the catalyst (hydroxide groups or oxygen anions).
    Notes: An amorphen Al2O3—SiO2-Katalysatoren unterschiedlichen Al2O3-Gehaltes wurden nach definierter Vergiftung der sauren Zentren mit Natriumäthylat aus alkoholischer Lösung die katalytischen Eigenschaften bei der Isopropanoldehydratisierung und bei der Cumolspaltung untersucht. Die Natriumbehandlung vermindert für beide Reaktionen die katalytische Aktivität, wobei die Cumolspaltung bereits bei niedrigeren Alkalikonzentrationen unterdrückt wird als die Isopropanoldehydratisierung. Der Charakter der Abhängigkeit der katalytischen Aktivität bei der Isopropanoldehydratisierung vom Alkaligehalt wird stark vom Al2O3-Gehalt der Katalysatoren beeinflußt. Für die Cumolspaltung sind stark saure BRÖNSTED-Zentren aktiv, während die Isopropanoldehydratisierung unter gemeinsamer Beteiligung von sauren Lewis- bzw. BrÖnsted-Zentren mit basischen Zentren der Katalysatoroberfläche (Hydroxidgruppen oder Sauerstoffionen) abläuft.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19744030109
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  • 7
    Electronic Resource
    Electronic Resource
    Hydroxidgruppen an Zeolithen. II. Zahl und Eigenschaften von Hydroxidgruppen an CeNaY- und HNaY-Zeolithen unterschiedlichen Austauschgrades (1974)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 404 (1974), S. 142-160 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Hydroxide Groups on Zeolites. II. Number and Properties of Hydroxide Groups on CeNaY and HNaY Zeolites of Different Exchange DegreeThe number of hydroxide groups on CeNaY and HNaY zeolites was examined by D2 exchange, and their properties in dependence of the cation exchange degrees were studied by IR spectroscopy. On CeNaY zeolites there exist six kinds and on HNaY zeolites at least seven kinds of hydroxide groups.On the CeNaY zeolites, the hydroxide groups are produced by dissociative chemisorption of water on Ce3+ ions. Their total number increases continuously with increasing exchange degree. Some of the hydroxide groups are acid BRÖNSTED centers whose number increases with increasing exchange degree and decreases with the temperature of preheating increasing to about 600°C.On the HNaY zeolites, the hydroxide groups are produced by thermal decomposition of the NH+4 ions, by dealumination and interaction of the Al3+ ions produced in this way in the place of cations with water. Above the threshold value of 35% the total number of the hydroxide groups increases very rapidly with increasing exchange degree. One part of the hydroxide groups decreasing with increasing exchange degree acts as acid BRÖNSTED centers. The number of these centers does not decrease until at preheating temperatures above 450°C.
    Notes: An CeNaY- und HNaY-Zeolithen wurden durch D2-Austausch die Zahl und infrarotspektroskopisch die Eigenschaften der Hydroxidgruppen in Abhängigkeit vom Kationenaustauschgrad untersucht. Es existieren an CeNaY-sechs Arten und an HNaY-Zeolithen mindestens sieben Arten von Hydroxidgruppen.An den CeNaY-Zeolithen entstehen die Hydroxidgruppen durch dissoziative Chemisorption von Wasser an Ce3+-Ionen. Ihre Gesamtzahl wächst kontinuierlich mit steigendem Austauschgrad. Einige der Hydroxidgruppen sind saure BRÖNSTED-Zentren, deren Zahl mit steigendem Austauschgrad wächst und mit steigender Vorerhitzungstemperatur bis etwa 600°C sinkt.An den HNaY-Zeolithen entstehen die Hydroxidgruppen durch thermische Zersetzung der eingetauschten NH+4-Ionen und mit wachsendem Austauschgrad zunehmend durch das Herauslösen von Gitteraluminium und Wechselwirkung der so entstehenden Al3+-Ionen auf Kationenplätzen mit Wasser. Die Gesamtzahl der Hydroxidgruppen wächst oberhalb des Schwellenwertes von 35% sehr stark mit steigendem Austauschgrad an. Ein mit steigendem Austauschgrad abnehmender Anteil der Hydroxidgruppen wirkt als saure BRÖNSTED-Zentren, deren Zahl erst bei Vorerhitzungstemperaturen oberhalb von 450°C abnimmt.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19744040206
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  • 8
    Electronic Resource
    Electronic Resource
    Untersuchungen an oxidischen Katalysatoren. XXIX. Spektroskopische und katalytische Untersuchungen an Ni2+-, Co2+-, Cr3+- und Cu2+-ausgetauschten MordenitenProfessor Günther Rienäcker gewidmet (1979)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 452 (1979), S. 6-16 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies on Oxide Catalysts. XXIX. Spectroscopic and Catalytic Investigations on Ni2+-, Co2+-, Cr3+-, and Cu2+-exchanged MordenitesNiNaM, CoNaM, CrNaM und CuNaM (M = Mordenite) have been characterized by UV-VIS, EPR and i.r. spectroscopy and the results were compared with the catalytic activity and the activity-time-dependence in the cracking of n-octane and with the shape selectivity in the cracking of a n-octane and isooctane mixture. Water molecules acting as ligands of the exchanged cations are able to dissociate yielding Brönsted acidity. Brönsted sites may be regarded as catalytic active centers in the cracking reaction. Unreduced transition metal cations facilitate the “coking” of the mordenite.The unreduced chromium and cobalt cations for which a position within the main channel is expected, affect the diffusion of the branched paraffin molecule thus increasing shape selectivity.
    Notes: NiNaM, CoNaM, CrNaM und CuNaM (M = Mordenit) wurden durch UV-VIS-Spektroskopie, EPR- und IR-Untersuchungen charakterisiert und die erhaltenen Ergebnisse mit der katalytischen Aktivität und dem Aktivitäts-Zeit-Verhalten dieser Proben bei der Spaltung von n-Octan und der Formselektivität in der Spaltung eines Gemisches von n/iso-Octan verglichen. Wassermolekeln als Liganden der eingetauschten Kationen können dissoziieren und so einen Beitrag zur Brönsted-Acidität liefern. Die Brönsted-Zentren können als katalytisch aktive Zentren in der Spaltreaktion angesehen werden. Nichtreduzierte Übergangsmetallkationen vergrößern die Neigung des Mordenits zum „Verkoken“ wesentlich. Die nichtreduzierten Co2+- und Cr3+-Kationen, für die eine Position im Hauptkanal angenommen werden kann, wirken als zusätzliche Diffusionsbremse auf die verzweigte Paraffinmolekel und erhöhen die Formselektivität des Mordenits.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19794520103
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  • 9
    Electronic Resource
    Electronic Resource
    Untersuchungen an oxidischen Katalysatoren. XXXIV. Redoxverhalten des Nickels in NiNaY-Zeolithen 1. Reduzierbarkeit und Reoxydierbarkeit von Nickel in NiNaY-Zeolithen (1983)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 499 (1983), S. 213-222 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies on Oxide Catalysts. XXXIV. Redoxbehaviour of Nickel in Zeolite NiNaY. 1. Reducibility and Reoxidizability of Nickel in Zeolites NiNaYThe properties of metallic nickel in reduced (470-870 K) and reoxidized (470, 670 K) samples were studied by chemical analysis (reaction with K2Cr2O7) and spectroscopic methods (FMR, IR after CO adsorption, UV/VIS). The reduction of Ni2+ cations from oxidic clusters proceeds in an onestep reaction. Contrary to this, isolated Ni2+ cations are reduced stepwise to Ni+ cations and subsequently to metallic nickel. The reduction degree depends in characteristic manner on the reduction temperature. Metallic nickel which was reduced at temperatures 〈 620 K, can be completely reoxidized at 470 K. Higher temperatures result in metallic aggregations which are not completely reoxidized even at 670 K.
    Notes: Die Eigenschaften von metallischem Nickel in reduzierten (470-870 K) und reoxydierten (470, 670 K) NiNaY-Proben wurden durch chemische Analyse (Reaktion mit K2Cr2O7) und spektroskopische Untersuchungen (FMR, IR nach CO-Chemisorption und UV/VIS) charakterisiert. Die Reduktion der Ni2+-Kationen oxidischer Cluster erfolgt einstufig, während isoliert lokalisierte Ni2+-Kationen über Ni+-Kationen zum Metall reduziert werden. Entsprechend der Lokalisierung und dem Austauschgrad ändert sich der Reduktionsgrad des Nickels in charakteristischer Weise mit der Reduktionstemperatur. Metallisches Nickel, das bei Temperaturen 〈 620 K erhalten wurde, kann bei 470 K vollständig reoxydiert werden. Höhere Reduktionstemperaturen führen zu Nickelaggregationen, die selbst bei 670 K nicht vollständig reoxydierbar sind.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19834990424
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  • 10
    Electronic Resource
    Electronic Resource
    27Al-MAS-NMR- und IR-spektroskopische Untersuchungen zur Aluminium-Koordination in röntgenamorphen SiO2 —Al2O3-Festkörpern (1984)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 517 (1984), S. 167-176 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 27Al MAS N.M.R. and I.R. Investigations on the Aluminium Coordination in Amorphous Silica-Alumina GelsAmorphous silica-alumina of different Si/Al ratios have been investigated by 27Al magic-angle spinning n.m.r. (MAS n.m.r.) and i.r. spectroscopy. Aluminosilicate framework structures were found for the Na+- and NH4+-exchanged forms of the investigated gels. The thermal deammoniation of the NH4+-exchanged gels, producing the H+ forms, causes an irreversible damage of the aluminosilicate framework. This process is accompanied by a change of the coordination state of a part of the aluminium, converting AlO4 into AlO6 units. The progress of the solid-state reaction upon further thermal treatment of the H+ forms is reflected by a considerable broadening of the n.m.r. spectra and a decrease of the intensity. The possibility that well-known results, including those of nonframework aluminium, obtained for comparable zeolitic systems may also be valid for amorphous solids, is discussed.
    Notes: Es wurden röntgenamorphe SiO2—Al2O3-Festkörper unterschiedlicher Si/Al-Verhältnisse mit der 27Al-NMR-Spektroskopie unter Verwendung der schnellen Probenrotation um den Magischen Winkel (MAS) untersucht und IR-spektroskopisch charakterisiert. Die Na- und NH4-Formen dieser Substanzen besitzen Alumosilicatstruktur. Die zu den H-Formen führende thermische Deammonisierung der NH4-Formen bewirkt eine irreversible strukturelle Schädigung des Alumosilicatgerüsts. Dabei wird ein Teil der AlO4-Einheiten unter Koordinationszahlwechsel in AlO6-Einheiten umgewandelt. Das Fortschreiten der Festkörperreaktion mit weiterer thermischer Behandlung der H-Formen zeigt sich in einer starken Verbreiterung der NMR-Signale und in einer Verringerung der Nachweisintensität. Die Übertragbarkeit entsprechender Beobachtungen an vergleichbaren Zeolithen einschließlich des Auftretens von „Extragitter“-Aluminium auf amorphe Analoga wird diskutiert.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19845171016
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