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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Development genes and evolution 206 (1996), S. 344-348 
    ISSN: 1432-041X
    Keywords: Key words Regeneration ; Pattern formation ; Vitamin A ; Homeosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Homeosis, the ectopic formation of a body part, is one of the key phenomena that prompted the identification of the essential selector genes controlling body organization. Shared elements of such homeotic genes exist in all studied animal classes, but homeotic transformations of the same order of magnitude as in insects, such as the duplication of the thorax in Drosophila mutants, have not been described in vertebrates. Here we investigate the capacity of retinoic acid to modify tail regeneration in amphibians. We show that retinoic acid causes the formation of an additional body segment in regenerating tails of Rana temporaria tadpoles. A second pelvic section, including vertebral elements, pelvic girdle elements and limb buds, forms at the mid-tail level. This is the first report of a homeotic duplication of a whole body segment in vertebrate axial regeneration.
    Type of Medium: Electronic Resource
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  • 12
    ISSN: 1432-0568
    Keywords: Limb development ; Evolutionary mechanisms ; Bird origins ; Dinosaurs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The underlying theme of this study is the contribution of developmental mechanisms to the generation of morphological novelty in evolution. The syndesmosis tibiofibularis, an important structural and functional link between the two zeugopod bones of the bird hindlimb, is used as a model for evolutionary novelty. We analyze the structural, developmental and adaptive aspects of its origin in a combined descriptive, experimental, and comparative approach.The ontogeny of the syndesmosis in the chick embryo involves several developmental steps, including the formation of a separate cartilage rudiment that in turn stimulates the formation of an osseous crest on the tibia, which with eventually replace the cartilage element itself. Some of the epigenetic requirements for the formation of the cartilage element and the osseous crest are demonstrated by experimentally increasing the distance between the two zeugopod bones, an operation that results in the absence of both cartilage and crest. Although a syndesmosis tibiofibularis associated with an osseous crest on the tibiotarsus is unique to birds in extant vertebrates, the presence of a distinct crest at the corresponding location in theropod dinosaurs indicates that a syndesmosis also existed in this group of archosaurs.The results of the study suggest that in the case of the syndesmosis tibiofibularis phenotypic evolutionary novelty is based on a caenogenetic feature, i.e. a feature that initially arose in response to changing developmental conditions. In conclusion we propose a model for the stepwise evolutionary modification of the sauropsid hindlimb, integrating adaptive trends and developmental mechanisms that interactively determine the transformations of skeletal limb morphology. The syndesmosis tibiofibularis and the mechanisms of its formation are not only shown to have played a key-role in this process, but its presence in theropod dinosaurs also points towards the origin of birds.
    Type of Medium: Electronic Resource
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Electrical engineering 80 (1997), S. 183-189 
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents The application of numerical field calculation demonstrates that the amplitudes of the pair of field waves produced by a certain pair of permeance and m.m.f. waves are not equal any longer due to the effects of saturation. Within the paper a new method is given to calculate these amplitudes maintaining the interaction of permeance and m.m.f. waves but taking into account saturation. As an example the calculation of slot harmonics demonstrates the usefulness of the new method.
    Notes: Übersicht Mit Hilfe von numerischer Feldberechnung wird gezeigt, daß die Amplituden eines Feldwellenpaars, das durch das Zusammenwirken einer Leitwerts- und Durchflutungswelle entsteht, unter dem Einfluß der Sättigung nicht mehr gleich sind. In diesem Artikel wird ein Verfahren vorgestellt, mit dem diese Amplituden auch unter Berücksichtigung des Einflusses der Sättigung aus dem Zusammenwirken von Leitwerts- und Durchflutungswellen berechnet werden können. Am Beispiel der Berechnung der Nutungsharmonischen wird die Tauglichkeit des Verfahrens demonstriert.
    Type of Medium: Electronic Resource
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  • 14
    ISSN: 1432-0495
    Keywords: Key words Heavy metals ; Sediment India
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  The concentrations of various metals (Cr, Cu, Co, Fe, Mn, Ni, Pb, Zn, and Cd) were determined in recently deposited surface sediments of the Gomati River in the Lucknow urban area. Markedly elevated concentrations (milligrams per kilogram) of some of the metals, Cd (0.26–3.62), Cu (33–147), Ni (45–86), Pb (25–77), and Zn (90–389) were observed. Profiles of these metals across the Lucknow urban stretch show a progressive downstream increase due to additions from 4 major drainage networks discharging the urban effluents into the river. The degree of metal contamination is compared with the local background and global standards. The geoaccumulation index order for the river sediments is Cd〉Zn〉Cu〉Cr〉Pb. Significant correlations were observed between Cr and Zn, Cr and Cu, Cu and Zn and total sediment carbon with Cr and Zn. This study reveals that the urbanization process is associated with higher concentrations of heavy metals such as Cd, Cu, Cr, Pb, and Zn in the Gomati River sediments. To keep the river clean for the future, it is strongly recommended that urban effluents should not be overlooked before their discharge into the river.
    Type of Medium: Electronic Resource
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 56 (1978), S. 389-397 
    ISSN: 1432-1440
    Keywords: Renin ; Angiotensinogen ; Angiotensin II ; Aldosteron ; Lebercirrhose ; Renin ; Angiotensinogen ; Angiotensin II ; Aldosterone ; Cirrhosis of the liver
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Plasma renin activity (PRA), plasma renin concentration (PRC), angiotensinogen, angiotensin II (AT II) and plasma aldosterone were determined by radioimmunoassay in 77 patients with cirrhosis of the liver [group I: with ascites, untreated (n=23); group II: patients with ascites during treatment (n=32); group III: after removal of fluids, but under further spironolactone therapy (n=10); group IV: untreated subjects without ascites (n=12)]. With the exception of decreased angiotensinogen values in all groups ranging between 39% (group IV) and 73% (group III) no significant changes of the other parameters of the RAAS were found in untreated patients. A highly significant increase of PRA, PRC, AT II and plasma aldosterone was observed in treated cirrhotics with (group II) or without (group III) ascites. In the total series of patients AT II was closely related to PRA, PRC and aldosterone emphasizing again the predominant role of AT II to stimulate aldosterone secretion. Plasma sodium was inversely correlated to PRA, PRC, AT II and aldosterone, but no relationship was detected between these parameters of the RAAS and plasma potassium. Our results indicate that hyperaldosteronism in cirrhosis appears unlikely to be the major determinant of avid renal sodium retention and ascites formation. An increased activity of the RAAS is most often initiated by therapeutic factors and/or markedly altered electrolyte metabolism. Therefore, basal conditions of the patients to be studied must be well defined to exclude any artificially induced stimulation of the RAAS.
    Notes: Zusammenfassung Im Plasma von 77 Patienten mit Lebercirrhose [Gruppe I: unbehandelte Kranke mit Aszites (n=23); Gruppe II: dekompensierte Patienten während saluretischer Behandlung (n=32); Gruppe III: nach Aszitesausschwemmung, aber unter weiterer Spironolacton-Therapie (n=10); Gruppe IV: kompensierte, unbehandelte Cirrhosen (n=12)] wurden radioimmunologisch Reninaktivität (PRA) und Reninkonzentration (PRC), Angiotensinogen, Angiotensin II (AT II) und Aldosteron bestimmt. Abgesehen von einer Angiotensinogen-Verminderung zwischen 39% (Gruppe IV) und 73% (Gruppe III) in allen Gruppen waren bei unbehandelten Patienten in der Regel keine Veränderungen der übrigen Parameter des RAAS nachweisbar. Bei behandelten Kranken mit (Gruppe II) oder ohne (Gruppe III) Aszites fand sich eine hochsignifikante Zunahme der PRA, PRC, AT II- und Aldosteron-Plasmaspiegel. In der gesamten Cirrhosegruppe ergab sich eine enge, direkt proportionale Beziehung zwischen AT II und PRA, PRC sowie Aldosteron, was auf eine vorrangige Bedeutung von AT II für die Stimulierung der Aldosteronsekretion hindeutet. Die Plasma-Natriumkonzentration war invers zur PRA, PRC und zum AT II wie zum Aldosteron korreliert, jedoch konnte keine Beziehung zum Plasmakalium festgestellt werden. Aus den erhobenen Befunden geht hervor, daß ein Hyperaldosteronismus bei Cirrhosekranken kaum als Ursache für die übersteigerte renale Natriumretention und die Aszitesbildung in Frage kommt. Überwiegend wird die Stimulierung des RAAS erst durch therapeutische Eingriffe und/oder durch ausgeprägte Störungen des Elektrolyt-Stoffwechsels hervorgerufen. Daher sind genau definierte Ausgangsbedingungen für die Untersuchung von Cirrhosepatienten unerläßlich, um therapiebedingte Aktivitätssteigerungen des RAAS ausschließen zu können.
    Type of Medium: Electronic Resource
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  • 16
    ISSN: 1432-1440
    Keywords: Cod liver oil ; Prostanoids ; Fatty acid pattern ; Low density lipoprotein ; Diabetes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ten healthy and twenty diabetic volunteers (type 1) received 15 capsules (à 450 mg) cod liver oil for 2 weeks daily in addition to a “normal” diet. The levels of eicosapentaenoic acid in the plasma phospholipids of both groups were increased after the treatment. The inhibition of the prostacyclin formation by LDL was diminished when the LDL was isolated after the treatment in comparison to LDL taken in the same concentration and from the same donors before it. The thromboxane B2 (TXB2) synthesis capacity of clotting whole blood, thrombin-induced TXB2 formation by platelets as well as the 15(S)-hydroxy-11α,9α-epoxymethano-5Z, 13E-prostadienoic acid-induced platelet aggregation were not altered by the treatment in healthy volunteers, whereas in diabetics the TXB2 formation capacity of clotting whole blood was decreased after the treatment in comparison with before it.
    Type of Medium: Electronic Resource
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  • 17
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 65 (1987), S. 912-919 
    ISSN: 1432-1440
    Keywords: Heterogeneity of cardiac myxomas ; Immunohistology of cardiac myxomas ; Endothelial characteristics of cardiac myxomas ; Monoclonal antibodies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Histogenesis of cardiac myxoma is still unclear. Beside endothelial cells a variety of different cell types were detected in this benign cardiac tumor. Cryostat sections of four myxomas were analysed in the indirect immunoperoxidase technique using monoclonal antibodies (MoABs) directed against MHC class I and II antigens, as well as different surface determinants specific for endothelial cells or monocytes/macrophages. Tumor cells forming cell clusters and blood vessel like structures differed in their expression of endothelial antigens suggesting cellular heterogeneity within single and different myxomas. Like in fetal cardiac tissue vascular channels rarely carried HLA-class II antigens. Tumor cells carrying antigens of monocytes/macrophages, as well as intracellular alkaline phosphatase of endothelial cells could represent subpopulations of an early differentiation stage. This analysis further supports previous hypothesis of an endothelial origin of myxomas.
    Type of Medium: Electronic Resource
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  • 18
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 45 (1967), S. 265-269 
    ISSN: 1432-1440
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary In the present analysis, facts are presented to show, that among rats an inheritable deficiency of glucose-6-phosphatedehydrogenase in erythrocytes can be observed. Most probably in our case it is a mutation in a well controlled rat family. This deficiency of glucose-6-phosphatedehydrogenase persisted over many generations until the whole family died as a result of an animalhouse infection. The rate of mortality as well as frequency of sterility in the concerned family was remarcably high among the newborns and young ones. The biochemical evaluation of the material and the analysis of the mode of inheritance were not possible due to technical reasons.
    Notes: Zusammenfassung In den vorliegenden Untersuchungen wird gezeigt, daß bei der Ratte ein vererbbarer Glucose-6-Phosphatdehydrogenasemangel beobachtet werden kann. In unserem Fall handelt es sich mit großer Wahrscheinlichkeit um eine Mutation, die in einer gut überwachten Rattenfamilie auftrat. Der Glucose-6-Phosphatdehydrogenasemangel blieb über mehrere Generationen, bis zum Aussterben der Familie infolge eines Stallinfektes, nachweisbar. In dem befallenen Familienzweig war eine über dem Durchschnitt liegende Absterberate der Neugeborenen und der Jungen, sowie die Häufigkeit von Sterilität auffällig. Die biochemische Auswertung des Materials, sowie eine Analyse des Vererbungsmodus war aus äußeren Gründen nicht möglich.
    Type of Medium: Electronic Resource
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  • 19
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 60 (1982), S. 317-318 
    ISSN: 1432-1440
    Keywords: Adenosine deaminase ; Lymphocytes ; Cell-mediated immunity ; Hodgkin's disease ; Adenosine deaminase ; Lymphozyten ; Zellvermittelte Immunität ; Morbus Hodgkin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Aktivität der Adenosindesaminase (EC3.5.4.4.) ADA in Blutplasma, Erythrozyten und Lymphozyten wurde bei 23 Patienten mit Morbus Hodgkin und teilweise bei 99 Referenzpersonen bestimmt. Die Enzymaktivitäten wurden mit Adenosin als Substrat und durch Analyse des Ammoniaks gemessen. Zwischen den ADA-Aktivitäten in Blutplasma, Erythrozyten und Lymphozyten wurde keine Korrelation festgestellt. Die Lymphozyten der Patienten wiesen niedrigere ADA-Aktivitäten auf als die Lymphozyten der Referenzpersonen. Die ADA-Aktivität in Plasma oder Erythrozyten ist nicht vermindert. Die herabgesetzten ADA-Aktivitäten in den Lymphozyten der Patienten können zur gestörten zellvermittelten Immunantwort bei Morbus Hodgkin in Beziehung gesetzt werden.
    Notes: Summary The activity of adenosine deaminase (ADA) (EC3.5.4.4.) was determined in the blood plasma, erythrocytes, and lymphocytes of 23 patients with Hodgkin's disease and partly also in 99 control subjects. The enzyme activities were measured using adenosine as substrate and by analysis of ammonia. No correlation was found between the ADA activities in lymphocytes, erythrocytes, and blood plasma. The lymphocytes of the patients revealed lower ADA activities (U/g protein) than the lymphocytes of control subjects. The ADA activity is not reduced in plasma or erythrocytes. The lower activities of ADA in the lymphocytes of patients may be related to the impaired cell-mediated immunity of the Hodgkin's disease.
    Type of Medium: Electronic Resource
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  • 20
    ISSN: 1432-1440
    Keywords: MHC ; Cadaver kidney transplantation ; Graft survival rate ; Blood transfusions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The influence of prospective HLA-DR matching on the graft survival rate was investigated in a multicenter analysis of 85 transplants. Simultaneously in a retrospective analysis of graft outcome the importance of matching for MT-antigens MT1, MT2 and MT3 as a newly defined B-cell alloantigen system was evaluated. HLA-DR antigens and MT-specificities were determined on B-cells enriched by nylon-wool filtration using locally well characterised HLA-DR antisera and the antiserum set of the 8th International Histocompatibility Workshop (“discase set”) which allowed the definition of the HLA-DR specificities HLA-DR 1–9 and of the MT-antigens MT 1–3. HLA-DR matching showed a significantly improved graft outcome only in HLA-DR identical donor-recipient combinations. In 11 of 60 patients with one HLA-DR compatibility additional matching for two MT-antigens, however, improved the two year graft survival rate from 60% to 91%. Altogether 17 patients were matched for two MT-specificities with their kidney donor and showed a superior prognosis of 94% at two years compared to 53% or 17% of recipients with one or zero MT compatibility. Graft outcome in this patient group was also superior to that of HLA-DR identical or HLA-AB identical grafts. These data suggested that the MT-system rather than the HLA-DR antigens may be of critical importance in cadaver kidney transplantation. In addition a favorable influence of pretransplant blood transfusions on less HLA-DR matched grafts was confirmed.
    Type of Medium: Electronic Resource
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