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  • Analytical Chemistry and Spectroscopy  (20)
  • Datenerhebung  (2)
  • Metabolism  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Ribose administration during exercise: Effects on substrates and products of energy metabolism in healthy subjects and a patient with myoadenylate deaminase deficiency (1991)
    Springer
    Journal of molecular medicine 69 (1991), S. 151-155 
    Details
    ISSN: 1432-1440
    Keywords: Myoadenylate deaminase ; AMP-deaminase ; Deficiency ; Ribose ; Lactate ; Ammonia ; Hypoxanthine ; Muscle ; Metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Nine healthy men and a patient with myoadenylate deaminase deficiency were exercised on a bicycle ergometer (30 minutes, 125 Watts) with and without oral ribose administration at a dose of 2 g every 5 minutes of exercise. Plasma or serum levels of glucose, free fatty acids, lactate, ammonia and hypoxanthine and the urinary hypoxanthine excretion were determined. After 30 minutes of exercise without ribose intake the healthy subjects showed significant increases in plasma lactate (p〈0.05), ammonia (p〈0.01) and hypoxanthine (p〈0.05) concentrations and a decrease in serum glucose concentration (p〈0.05). When ribose was administered, the plasma lactate concentration increased significantly higher (p〈 0.05) and the increase in plasma hypoxanthine concentration was no longer significant. The patient showed the same pattern of changes in serum or plasma concentrations with exercise with the exception of hypoxanthine in plasma which increased higher when ribose was administered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01665856
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  • 2
    Electronic Resource
    Electronic Resource
    Metabolism of D-ribose administered continuously to healthy persons and to patients with myoadenylate deaminase deficiency (1989)
    Springer
    Journal of molecular medicine 67 (1989), S. 1205-1213 
    Details
    ISSN: 1432-1440
    Keywords: (D-)ribose ; Metabolism ; Myoadenylate ; (adenylate-, AMP-)deaminase deficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary D-ribose was administered orally or intravenously over at least 5 h to eight healthy volunteers and five patients with myoadenylate deaminase deficiency. Intravenous administration rates were 83, 167, and 222 mg/kg/h, which were well tolerated but oral administration of more than 200 mg/kg/h caused diarrhea. The average steady state serum ribose level ranged between 4.8 mg/100 ml (83 mg/kg/h, oral administration) and 81.7 mg/100 ml (222 mg/kg/h, intravenous administration). Serum glucose level decreased during ribose administration. The intestinal absorption rate of orally administered ribose was 87.8%–99.8% of the intake at doses up to 200 mg/kg/h without first pass effect. Urinary losses were 23% of the intravenously administered dose at 222 mg/kg/h. Ribose appeared to be excreted by glomerular filtration without active reabsorption; a renal threshold could not be demonstrated. The amount of ribose transported back from the tubular lumen depended on the serum ribose level. There was no difference in ribose turnover in healthy subjects and patients with MAD deficiency.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01716208
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  • 3
    Electronic Resource
    Electronic Resource
    Wird die Diagnose bei persistierenden kindlichen Hörstörungen immer noch zu spät gestellt? (1998)
    Springer
    HNO 46 (1998), S. 598-602 
    Details
    ISSN: 1433-0458
    Keywords: Schlüsselwörter Diagnosezeitpunkt ; Verzögerte Diagnose ; Medizinische Register ; Datenerhebung ; Kindliche Hörstörungen ; Key words Age at diagnosis ; Delay of diagnosis ; Medical registries ; Data collection ; Hearing loss in childhood
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Since 1994, the German Registry for Hearing Loss in Children has registered data of 1500 children and by now can present results concerning the age at diagnosis of permanent hearing loss in children in Germany. The mean age at diagnosis is still very high. There is a strong correlation between age at diagnosis and degree of hearing loss, i.e., severe and profound hearing loss, is diagnosed distinctly earlier than mild and moderate hearing loss. On average, mild hearing loss is diagnosed with 6.2 years, moderate h.l. with 4.4 years, severe hearing loss with 2.5 years and profound hearing loss with 1.9 years. This corresponds with the results of regional German studies. At least regionally, in other European countries the age at diagnosis is known to be distinctly lower. In 36% of the children registered in Germany the delay between first suspicion and diagnosis of permanent hearing loss is 1 year or more.
    Notes: Zusammenfassung Das Deutsche Zentralregister (DZH) für kindliche Hörstörungen hat seit 1994 Patientendatensätze von 1500 Kindern erfaßt und kann mittlerweile u.a. Aussagen und Ergebnisse zum Diagnosezeitpunkt persistierender kindlicher Hörstörungen in der Bundesrepublik Deutschland vorlegen. Nach wie vor ist das mittlere Alter bei der Diagnose persistierender kindlicher Hörstörungen sehr hoch. Das Diagnosealter korreliert stark mit dem Grad der Hörstörung, d.h. an Taubheit grenzende und hochgradige Hörstörungen werden deutlich früher diagnostiziert als leichte und mittlere. So werden leichte Hörstörungen im Durchschnitt erst mit 6;2 Jahren diagnostiziert, mittlere mit 4;4 Jahren, hochgradige mit 2;5 Jahren und an Taubheit grenzende mit 1;9 Jahren. Dies entspricht den Ergebnissen bereits vorliegender regionaler deutscher Studien [1–2]. Aus anderen europäischen Länderen sind zumindest regional deutlich frühere Diagnosezeitpunkte bekannt [3–5]. Bei 36% der im DZH erfaßten Kinder liegt zwischen dem ersten Verdacht auf Vorliegen einer persistierenden kindlichen Hörstörung und der Sicherstellung der Diagnose ein Jahr und mehr.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001060050279
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  • 4
    Electronic Resource
    Electronic Resource
    Datenschutz innerhalb des länderübergreifenden Deutschen Zentralregisters für kindliche Hörstörungen (1998)
    Springer
    HNO 46 (1998), S. 339-345 
    Details
    ISSN: 1433-0458
    Keywords: Schlüsselwörter Datenschutz ; Datensicherheit ; Medizinische Register ; Datenerhebung ; Kindliche Hörstörungen ; Key words Medical registries ; Data collection and security ; Hearing loss and childhood
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary The German Registry for Hearing Loss in Children (DZH) processes nationwide data from audiological centers. Coping with the accrued data and its subsequent management and analysis requires a high degree of security and control. To establish a nationwide registry it is necessary at an early stage to take into consideration the legal requirements of the participating states. Use of the DZH as an example demonstrates how a pragmatic solution can be reached. Special issues concerning data collection, transfer, storage and deletion, coding strategies to ensure anonymity, checking for duplicate entries, data separation, and automated data analysis and data protection are explained.
    Notes: Zusammenfassung Das Deutsche Zentralregister für kindliche Hörstörungen (DZH) verarbeitet bundesweit Daten von verschiedenen audiologischen Einrichtungen. Die Bewältigung der anfallenden Datenmengen, die nachfolgende Datenverwaltung und -analyse erfordern neben einer differenzierten und kontrollierbaren Verarbeitung ein Höchstmaß an Datensicherheit. Vor allem die länderübergreifende Struktur eines Registers erfordert schon bei der Planung engste Zusammenarbeit mit dem zuständigen Landesdatenschutzbeauftragten und auch mit den Landesdatenschutzbeauftragten anderer beteiligter Bundesländer. Am Beispiel des DZH wird demonstriert, wie eine kooperative Zusammenarbeit pragmatisch realisiert werden kann. Besonderheiten bei der Datenerhebung, Datentransfer, Speicherung und Löschung von Daten, technische Datenschutzmaßnahmen, Sicherstellung von Anonymität durch Codierungsstrategien, Duplikatsprüfung, Datentrennung und automatisierte Datenauswertung werden an Beispielen erläutert.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001060050249
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  • 5
    Electronic Resource
    Electronic Resource
    FAB and tandem mass spectrometry for endorphin- and ACTH peptides of molecular weight to 2000 (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 649-657 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Four β-endorphins (β-endorphin 6-17, 2-17, 1-16, and 1-17) and two adrenocorticotropic hormone (ACTH) peptides (ACTH 1-10 and (1-16)-NH2) were studied by using fast atom bombardment coupled with tandem mass spectrometry. The capability to reproduce metastable ion and collisionally activated decomposition spectra on two different commercial sector mass spectrometers in two different laboratories was found to be acceptable (deviations in relative abundance are less than ± 50%). The endorphin peptides fragment metastably or upon collisional activation to give abundant B-series ions as well as Y-series ions, whereas Y-series ions are the principal ionic species produced upon the desorption by fast atom bombardment. The ACTH peptides also fragment to give Y-series ions, but of relatively low abundance compared to those from the endorphins. For both sets of peptides, high-energy collisionally activated decomposition and metastable ion decomposition daughter ion spectra are precise, structurally informative - even for peptides up to m/z 2000 - and complementary to spectra of daughter ions produced by desorption ionization alone.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200151203
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  • 6
    Electronic Resource
    Electronic Resource
    Fast atom bombardment and tandem mass spectrometry for structure determination: Remote site fragmentation of steroid conjugates and bile salts (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 89-98 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of 35 steroid conjugates (sulfates and glucuronides) and bile salts were investigated by using fast atom bombardment and tandem mass spectrometry. Collisional activation of the [M - H]- anions of sulfate conjugates and bile salts predominantly yields fragment ions arising by reactions occurring remote from the charge site. These reactions are sometimes sensitive to differences in stereochemistry at positions remote from the charge site and are useful for positional isomer differentiation. On the other hand, collisional activation of the [M - H]- anions of the glucouronide conjugates leads primarily to charge-driven fragementations.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200150206
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  • 7
    Electronic Resource
    Electronic Resource
    Reactions of propene and cyclopropane radical cations with neutral ethylene (1993)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 28 (1993), S. 185-192 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The gas-phase reactions of propene and cyclopropane radical cations with neutral ethylene were investigated by using Fourier transform, chemical ionization and tandem mass spectrometries. Both reactions form covalent C5H10 adduct ions. The adduct ions are hypothesized to form initially as distonic radical cations that isomerize via a substituted cyclopropane intermediate and are detected as the most stable C5H10 isomer, the 2-methylbut-2-ene radical cation. The rate constant for each reaction is approximately 20% of the theoretical collision rate, indicating that product ions are formed in one out of every five collisions of the C3H6 radical cations with neutral C2H4.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210280309
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  • 8
    Electronic Resource
    Electronic Resource
    Elucidation of some fragmentations of small peptides using sequential mass spectrometry on a hybrid instrument (1989)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 3 (1989), S. 217-221 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Sequential daughter-ion-scanning analyses of small peptides have been performed using a hybrid tandem instrument of BEqQ configuration. Precursor ions are selected by B and allowed or induced (by high-energy collisional activation) to decompose in the region preceding E. Decoupling of E from the accelerating voltage permits the selection of the first-generation daughter ion whilst retaining appropriate float voltages for the quadrupole assemblies. The daughter ion selected by E is further subjected to low-energy collisional-activation dissociation (CAD) in q and the fragment-ion spectrum is obtained by scanning Q. The sequential daughter-ion-scanning technique has been used to establish that ‘internal’ fragments of the types, (AY′) and (BY′), are formed via initial Y-type cleavage. Fragmentation of a protonated peptide (angiotensin III) by loss of the C-terminal amino acid residue, yielding a (Bn′ + OH) ion, is reported for the first time. This process is analogous to that previously described for metal-cationized peptides.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290030704
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  • 9
    Electronic Resource
    Electronic Resource
    The Chemistry of C6H6O radical cations: A study of rearrangement reactions of halogen substituted ethyl phenyl ethers (1979)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1979), S. 474-481 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New experimental data on the rearrangement reaction of various phenoxyethyl halides to give [C6H6O]+· are presented and compared with previous studies so that a coherent picture of this process can be developed. By examining the metastable kinetic energy release for low energy decomposing molecular ions of the phenoxyethyl halides, it has been concluded that formation of [C6H6O] occurs by competitive 1,2 and 1,3 hydrogen shifts from the alkyl carbons to oxygen followed by a rate determining C—O bond cleavage. This is substantiated by the absence of a primary hydrogen isotope effect. For more highly activated molecular ions, a new mechanism comes into play as evidenced by the appearance of a small hydrogen isotope effect. It is postulated that this third mechanism involves transfer of the alkyl hydrogen to the ortho position of the ring by a rate determining 1,5 shift, followed by a 1,3 hydrogen shift from the ortho methylene group to oxygen and rapid C—O bond cleavage. This 1,3 hydrogen shift to oxygen appears to be ‘catalysed’ by the halogen atoms yielding phenol ions. No indications have been found for the formation of tautomeric 2,4-cyclohexadienone ions. Furthermore, highly activated molecular ions produce [C6H6O]+· which can undergo metastable decomposition to lose carbon monoxide. Kinetic energy release measurements for the latter reaction show that the majority of these [C6H6O]+·ions have been formed as phenol ions as well. These arguments are supported by energetic measurements and by comparisons with previous ion cyclotron resonance and collisional activation studies.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210140904
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  • 10
    Electronic Resource
    Electronic Resource
    Stereochemistry of HOH and HOAc elimination from 1-tetralol and 1-acetoxytetralin radical cations (1982)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 17 (1982), S. 269-273 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Water and acetic acid eliminations from 1-tetralin radical cations have been shown previously to be highly regiospecific 1,4 processes. Utilizing deuterium labeling, high resolution peak ratio measurements and metastable ion defocusing techniques, the stereochemistry of these processes has been investigated. cis-4-d1- and trans-4-d1-1-Tetralol both lose HOH and DOH in appreciable amounts; similarly, both acetoxy derivatives lose HOAc and DOAc. These results are interpreted in terms of an ionic epimerization which operates in competition with a stereospecific 1,4 elimination mechanism. A hydrogen exchange process which occurs between the 4-carbon and the oxygen atom situated on the 1-carbon of 1-tetralol has also been observed. This process accounts for observed H/D ratios in the ethene elimination reaction of various deuterium labeled 1-tetralols.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210170606
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