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  • 1
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cytogenetic and molecular genetic findings in 91 patients with Turner syndrome are reported. In 87 patients, chromosome studies were carried out both in lymphocyte and fibroblast cultures. Mosaicism was demonstrated in 58 of these patients (66.7%), whereas only 18 (20.7%) were apparent non-mosaic 45,X, and 11 patients (12.6%) showed non-mosaic structural aberrations of the X chromosome. Among the mosaic cases 16 (18.4% of all patients) displayed a second cell line containing small marker chromosomes. The association of Y-specific chromosomal material with the presence of marker chromosomes was demonstrated in 6 out of 7 mixoploid fibroblast cell lines by polymerase chain reaction amplification and by Southern-blot analysis. The observation of ring formation and morphological variability in vivo and in vitro, and the continous reduction in the percentage of cells containing marker chromosomes in longterm cultivation experiments indicated an increased instability of marker chromosomes. The findings suggest that in vivo selection of structurally altered sex chromosomes exists. Thus, the observation of apparent non-mosaic 45,X chromosomal complements in liveborn individuals with Turner syndrome does not contradict the hypothesis that some degree of mosaicism is necessary for survival in early pregnancy.
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  • 3
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung 1. Der Vergleich der tryptischen Peptide von normaler und dibucain-resistenter Pseudocholinesterase zeigte eine unterschiedliche elektrophoretische Beweglichkeit für die mit radioaktivem DFP markierbaren Peptide. Die Ergebnisse ließen auf den Verlust einer negativen Ladung in der Nähe der esteratischen Stelle des aktiven Zentrums bei der Enzymvariante schließen. 2. Die quantitative Untersuchung der interindividuellen Variabilität des Pseudocholinesteraseantigens und der Enzymaktivität in einer Stichprobe der Bevölkerung ergab eine enge Korrelation der Werte. Seren, die die C5-Variante enthielten, hatten mehr Pseudocholinesteraseantigen als C5-negative Seren. Die Möglichkeit der Erkennung subtoxischer Insecticidbelastungen wurde aufgezeigt. 3. Immunologische und biochemische Untersuchungen an kultivierten menschlichen Fibroblasten von normalen und enzymdefizienten Individuen ergaben keine Evidenz für die Synthese von Pseudocholinesterase.
    Notes: Summary 1. The comparison of the tryptic peptides of usual and dibucain-resistent Pseudocholinesterase revealed a different electrophoretic mobility of those peptides which can be labelled with radioactive DFP. The results suggested the loss of a negative charge near the esteratic site of the active center in the variant enzyme. 2. The investigation of quantitative interindividual variation of Pseudocholinesterase antigen and enzyme activity in a sample of the population showed a high correlation of the values. Sera containing the C5-variant have more antigen than C5-negative sera. A possibility to detect subtoxic exposure to organophosphates was pointed out. 3. Immunological and biochemical investigations on human cultured fibroblasts from normal and enzyme deficient individuals failed to give evidence for the synthesis of Pseudocholinesterase.
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  • 4
    ISSN: 1432-1076
    Keywords: Farber disease ; Lipogranulomatosis ; Acid ceramidase deficiency ; Arthropathy ; Hoarseness ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A 20-month-old girl showed typical clinical signs of Farber disease: hoarseness since birth, and periarticular subcutaneous painful nodules. Complete deficiency of acid ceramidase activity was found in cultured skin fibroblasts. An electron microscopic examination of a dermal nodule disclosed pathognomonic tubular inclusions in histiocytes. In epidermal cells zebra-body-like and needle-like lysosomal inclusions were found. Their ultrastructure is different from that of the intrahistiocytic lysosomal inclusions. Probably three clinical types of Farber disease may be distinguished according to the symptomatology and the course of the discase: a severe type, an intermediate type and a relatively mild type. The activity of acid ceramidase does not correlate with prognosis of the disease, while a correlation between first appearance of dermal nodules and clinical course appears likely.
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  • 5
    ISSN: 1432-0584
    Keywords: Chronic myelogenous leukemia ; Trisomy 8 ; Trisomy 8 mosaicism syndrome ; Constitutional disorders
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A 17-year-old woman was admitted for bone marrow transplantation with the diagnosis of atypical Philadelphia-negative chronic myelogenous leukemia (aCML), cytogenetically characterized by trisomy 8 as the sole chromosome aberration. A striking feature was a congenital opacity of the right cornea. Chromosomal analysis of skin fibroblasts were performed and revealed a mosaic for trisomy 8. Commonly, a distinct clinical picture leads to the diagnosis of trisomy 8 mosaicism syndrome (T8ms), but an extreme phenotypic variability has been observed. To our knowledge the development of an aCML in a patient with T8ms has not been reported. A review of the literature revealed that an association to other hematological disorders had been described in two cases. The question of whether our patient's aCML was a random event or not is discussed. The patient is now 24 months post transplant and shows no evidence of disease. Her Karnofsky score is 100%. We conclude that it might be worthwhile to look for an associated constitutional trisomy 8 mosaicism in all patients with trisomy 8 leukemia.
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  • 6
    ISSN: 1434-6036
    Keywords: PACS. 71.27.+a Strongly correlated electron systems; heavy fermions - 75.10.Lp Band and itinerant models - 75.30.Kz Magnetic phase boundaries
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: The importance of Hund's rule coupling for the stabilization of itinerant ferromagnetism is investigated within a two-band Hubbard model. The magnetic phase diagram is calculated by finite-temperature quantum Monte-Carlo simulations within the dynamical mean-field theory. Ferromagnetism is found in a broad range of electron fillings whereas antiferromagnetism exists only near half filling. The possibility of orbital ordering at quarter filling is also analyzed.
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  • 7
    ISSN: 1434-6036
    Keywords: PACS. 71.27.+a Strongly correlated electron systems; heavy fermions - 71.10.Fd Lattice fermion models (Hubbard model, etc.) - 71.30.+h Metal-insulator transitions and other electronic transitions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: We show analytically that, under certain assumptions, the periodic Anderson model and the Hubbard model become equivalent within the dynamical mean field theory for quasiparticle weight . A scaling relation is derived which is validated numerically using the numerical renormalization group at zero temperature and quantum Monte Carlo simulations at finite temperatures. Our results show that the f-electrons of the half-filled periodic Anderson model with nearest neighbor hybridization get localized at a finite critical interaction strength , also at zero temperature. This transition is equivalent to the Mott-transition in the Hubbard model.
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  • 8
    ISSN: 1434-6036
    Keywords: PACS. 71.27.+a Strongly correlated electron systems; heavy fermions - 74.25.Jb Electronic structure - 79.60.-i Photoemission and photoelectron spectra
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: The spectral properties of La1–xSrxTiO3, a doped Mott insulator with strong Coulomb correlations, are calculated with the ab initio computational scheme LDA+DMFT(QMC). It starts from the non-interacting electronic band structure as calculated by the local density approximation (LDA), and introduces the missing correlations by the dynamical mean-field theory (DMFT), using numerically exact quantum Monte-Carlo (QMC) techniques to solve the resulting self-consistent multi-band single-impurity problem. The results of the LDA+DMFT(QMC) approach for the photoemission spectra of La1–xSrxTiO3 are in good agreement with experiment and represent a considerable qualitative and quantitative improvement on standard LDA calculations.
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  • 9
    ISSN: 1432-1440
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary The changes in systolic and diastolic arterial pressures during diastolic augmentation with pump volumes varying from 2–20 ml were studied in 19 dogs. Increases in stroke volume of the counterpulsator led to a paralleling drop in maximal and mean systolic pressure, whereas maximal diastolic pressure could be elevated. Hence with larger pump volumes a change in the arterial pulse configuration could result. The possible complications which may occur with the quick periodical pumping of volumes up to 20 ml as to hemolysis and changes in peripheral arterial flow to various organs are discussed.
    Notes: Zusammenfassung An 19 Hunden wurden in insgesamt 66 Gegenpulsationsserien mit Hubvolumina von 2–20 ml die Veränderungen des maximalen und mittleren systolischen sowie des maximalen und mittleren diastolischen Aortendruckes untersucht. Dabei zeigte sich, daß der systolische Druck mit zunehmenden Hubvolumina in verstärktem Maße absinkt. Der mittlere diastolische Druck dagegen fällt wesentlich weniger ab als der mittlere systolische Druck, so daß es, insbesondere bei größeren Hubvolumina, zu einer Annäherung beider Drucke und zu einer eindrucksvollen Umkehr des Kurvenprofils kommen kann. In Anbetracht einer möglichen klinischen Anwendung des Verfahrens der arteriellen Gegenpulsation wird auf die möglichen Komplikationen hingewiesen, die mit der rasch erfolgenden periodischen Verschiebung größerer Hubvolumina auftreten können.
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  • 10
    ISSN: 1432-1440
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 1. Bei 44 Stoffwechselgesunden, 20 Diabetikern und 5 Kranken mit Lebercirrhose wurde der Gehalt an nicht-veresterten Fettsäuren im arteriellen und hirn venösen Blut bestimmt. Signifikante A-V-Differenzen konnten weder im Mittel aller Messungen, noch bei erhöhtem Blutspiegel von Diabetikern oder bei intravenöser Infusion einer Fettlösung nachgewiesen werden. Damit ergab sich kein Anhalt für eine cerebrale Utilisation von nicht-veresterten Fettsäuren. 2. Bei 29 Patienten, die nur 12–16 Std nüchtern waren, wurden im arteriellen und hirnvenösen Blut Acetacetat undβ-Hydroxybutyrat enzymatisch bestimmt. Dabei ergaben sich statistisch signifikante A-V-Differenzen. 3. Bei 16 Normalpersonen betrugen die arterio-hirnvenösen Differenzen für Acetacetat 0,03 µMol/ml, fürβ-Hydroxybutyrat 0,01 µ Mol/ml und für die Gesamtketonkörper 0,04 µMol/ml. Der arterielle Ketonkörpergehalt lag bei 0,73 µMol/ ml. 4. Bei 5 Kranken mit chronischer Urämie (Harnstoff-N 80 mg-%, pH art. 7,28) lag der arterielle Ketonkörperspiegel mit 1,18 µMol/ml signifikant über dem der Normalpersonen. Die arterio-hirnvenösen Differenzen betrugen für Acetacetat 0,03 µMol/ml, fürβ-Hydroxybutyrat 0,07 µMol/ml und für die Gesamtketonkörper 0,10 µMol/ml. Die Ketonkörper-A-V-Differenzen sind gegenüber dem Normalkollektiv statistisch signifikant erhöht. 5. Bei 2 Kranken mit ausgeprägter cerebraler Arteriosklerose sowie bei 1 Kranken mit Leberinsuffizienz waren die arteriellen Blutspiegel und A-V-Differenzen ebenfalls erhöht. 6. Bei 5 Diabetikern ohne Stoffwechselentgleisung waren die arteriellen Blutspiegel und A-V-Differenzen normal. 7. Es besteht eine statistisch signifikante Korrelation zwischen Höhe des Ketonkörperblutspiegels und Größe der A-V-Differenz. 8. Bei 8 Kranken (5 Hirnarteriosklerosen, 2 Urämien, 1 Leberinsuffizienz) wurde eine Stoffwechselbilanz ermittelt: Hirndurchblutung 49,6 ml/100 g·min, O2-Verbrauch 3,01 ml/100 g·min, Glucoseverbrauch 4,04 mg/100 g·min, Acetacetatverbrauch 0,12 mg/100 g·min,β-Hydroxybutyratverbrauch 0,23 mg/100 g·min, Gesamtketonkörperaufnahme somit 0,35mg/100 g·min, Lactatabgabe 0,51 mg/100 g·min, CO2-Abgabe 2,59 ml/100 g·min. Der Glucoseoxydationsquotient (Glucose-A-V-Differenz minus Lactat-A-V-Differenz: O2-A-V-Differenz) war mit 1,17 stark reduziert. Unter Berücksichtigung der Sauerstoffäquivalente für die vom Hirn aufgenommenen Ketonkörper ergibt sich ein fast normaler Quotient von 1,32. Etwa 10 % des aufgenommenen Sauerstoffs wurde bei diesen Kranken für die Oxydation der Ketonkörper verbraucht. 9. Mit unseren Befunden konnten wir nachweisen, daß das Gehirn des Menschen unter normalen und besonders unter bestimmten krankhaften Bedingungen nicht ausschließlich Glucose zur Energiegewinnung oxydativ und glycolytisch abbaut, sondern auch Ketonkörper utilisiert.
    Notes: Summary (1) In 44 subjects without metabolic diseases, 20 diabetics and 5 patients with liver cirrhosis, non-esterified fatty acid levels were assessed in the arterial and cerebral venous blood. No significant a-v differences were found in either the mean values of all measurements or in the single groups showing elevated blood fatty acid levels (i.e. diabetics or after intravenous infusion of a fatty emulsion). These findings suggest that there is no utilisation of non-esterified fatty acids by the brain. (2) Acetoacetate andβ-hydroxybutyrate in the arterial and cerebral venous blood were assayed enzymatically in 29 patients fasted for only 12–16 hours. The measurements revealed significant a-v differences. (3) In 16 normal subjects the mean arterial-cerebral venous difference of acetoacetate was 0.03 µM/ml, that ofβ-hydroxybutyrate 0.01 µM/ml, and that of the total ketone bodies 0.04 µM/ml. The arterial level of the ketone bodies was 0.71 µM/ml. (4) In 5 patients with chronic uremia (BUN 80 mg-%, art. pH 7.28) the mean arterial level of ketone bodies (1.18 µ M/ml) exceeded significantly the values found in normal subjects. The a-v differences attained 0.03 µM/ml for acetoacetate, 0.07 µM/ml forβ-hydroxybutyrate and 0.10 µM/ml for total ketone bodies. Compared with the normal values, the a-v difference of the total ketone bodies is significantly elevated. (5) In 2 patients with severe cerebral arteriosclerosis and in 1 patient with hepatic insufficiency the arterial levels and the a-v differences were also elevated. (6) A-v differences were normal in 5 diabetics without acidosis nor ketonaemia. (7) There exists a significant correlation between the arterial level and the a-v differences of ketone bodies (p〈0.01). (8) In 8 patients (5 cerebral arteriosclerosis, 2 uremia, 1 hepatic insuffieiency) the metabolic balance of the brain was calculated: cerebral blood flow 49.6 ml/100 g·min, cerebral oxygen uptake 3.01 ml/100 g·min, cerebral glucose uptake 4.04 mg/100 g·min, cerebral acetoacetate uptake 0.12 mg/100 g·min, cerebralβ-hydroxybutyrate uptake 0.23 mg/100 g·min, cerebral lactate release 0.51 mg/100 g·min cerebral CO2 release 2.59 ml/100 g·min. The glucose-oxygen quotient (glucose a-v difference minus lactate a-v difference divided by oxygen a-v difference) was markedly reduced (1.17). Taking into account the oxygen substrate equivalents of the ketone bodies utilized by the brain an almost normal glucoseoxygen quotient results (1.32). In these patients about 10 % of the oxygen consumed was required for the oxydation of the ketone bodies. (9) Our findings clearly demonstrate that under normal and especially under certain pathological conditions the human brain derives the energy required not only by the oxydative and glycolytic metabolization of glucose but also by the oxydative breakdown of ketone bodies.
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