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  • 1
    ISSN: 1434-4726
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Recently vitamin A has been shown to have an inhibitory effect on the carcinogenic potential of tobacco smoke constituents and vitamin A deficiency has been reported to be capable of reducing the tumor induction time in the respiratory tract of animals treated with polycyclic aromatic hydrocarbons. Prospectives epidemiological investigations have shown an inverse association between vitamin A and risk of lung cancer. We have done therefore histologic and electron microscopic investigations on the influence of a chronic vitamin A deficit diet on the epithelial structures of trachea in rats. Further we measured vitamin A, RBP and zinc in the blood in alcoholics, cancer patients and controls. After 12 week of a vitamin A deficit diet the male rats showed focal metaplasias. Mean levels of vitamin A in patients with alcoholic liver diseases and in patients with head and neck cancer and simultaneous alcoholic liver diseases were deceased compared to healthy controls and patients with head neck cancer without liver diseases. The mean levels for zinc and RBP were in the groups with liver diseases likewise decreased compared with the two others groups. We conclude that the chronic alcoholism leads to a vitamin A deficit in humans and this may be one cause for the higher risk for cancer in chronic alcoholics.
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  • 2
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1600-0765
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The local salivary immunoglobulin A (IgA) response in patients with aggressive periodontitis to oral microorganisms and its role for the pathogenesis has not been determined. This study investigated the hypothesis that aggressive periodontitis patients have impaired oral secretory immunity. Our test group was made-up of 19 aggressive periodontitis patients and 19 age- and gender-matched periodontally healthy controls. Total IgA, IgA subclass 1, IgA subclass 2 and IgA reactive to Actinobacillus actinomycetemcomitans Y4, Treponema denticola ATCC 35404 and Candida albicans DSM 3454 were determined by enzyme-linked immunosorbent assay in whole unstimulated and stimulated saliva. A statistically significantly lower concentration and secretion rate of total salivary IgA (P 〈 0.01) and IgA1 (P 〈 0.001) was found in the aggressive periodontitis group in resting and stimulated saliva. A decrease of IgA2 (P 〈 0.05) was seen in resting saliva. Although only minor differences were detected in the concentration and secretion of bacteria-reactive IgA in both groups, the proportion of bacteria-reactive IgA from the total IgA was significantly higher (P 〈 0.01) in the aggressive periodontitis group in all three microorganisms tested. Our results indicate an inhibition of total secretory IgA. In particular an IgA subclass 1-specific decrease in aggressive periodontitis was noted, while the bacteria-reactive humoral immune system in saliva was activated. The role of the decrease of IgA1 immunoglobulins in aggressive periodontitis with respect to susceptibility for periodontal diseases has to be elucidated.
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  • 4
    ISSN: 1573-4986
    Keywords: Vitamin A ; retinol ; N-linked oligosaccharides ; membrane glycoproteins ; dipeptidylpeptidase IV
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The effect of vitamin A deficiency onN-linked oligosaccharides of membrane glycoproteins was studied in rat liver in order to evaluate the suggested role of retinol in proteinN-glycosylation. First, oligosaccharides of newly synthesized glycoproteins from rough endoplasmic reticulum of vitamin A deficient liver were compared with that of pair-fed controls. Oligosaccharides were metabolically labelled withd-[2-3H]mannose, released from the glycoproteins with endoglycosidase H, purified by reversed phase HPLC and ion exchange chromatography, and were reduced with sodium borohydride. HPLC fractionation of the oligosaccharide alditols showed that the glycoproteins carried mainly four oligosaccharide species, Glc1Man9GlcNAc2, Man9GlcNAc2, Man8GlcNAc2 and Man7GlcNAc2, in identical relative amounts in the vitamin A deficient and the control tissue. In particular, no increase in the proportion of short chain oligosaccharides was noted in vitamin A deficient liver. Second, the number ofN-linked oligosaccharides was estimated in dipeptidylpeptidase IV (DPP IV), a major glycoprotein constituent of the hepatic plasma membrane, comparing the newly synthesized glycoprotein from rough endoplasmic reticulum and the mature form of DPP IV from the plasma membrane. No evidence was obtained that retinol deficiency caused incomplete glycosylation of this membrane glycoprotein. From these data, the suggested role of retinol as a cofactor involved in the synthesis ofN-linked oligosaccharides of glycoproteins must be questioned.
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  • 5
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
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  • 6
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-1440
    Keywords: Gamma-glutamyl isoenzymes ; Phytohaemagglutinins ; Affinity chromatography ; Liver diseases ; Kidney diseases ; Gamma-Glutamyltransferase ; Isoenzyme ; Phytohämagglutinine ; Affinitätschromatographie ; Lebererkrankungen ; Nierenerkrankungen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung In der vorliegenden Untersuchung wird eine neue Möglichkeit der Isoenzymdifferenzierung der Gamma-Glutamyltransferase (GGT) (EC Nr.2.3.2.2.) mit Hilfe von Concanavalin A und Con A-Sepharose aufgezeigt. Auf Grund des unterschiedlichen Zuckeranteils des Glykoproteins kann eine Unterscheidung zwischen Leber- und Nieren-GGT erreicht werden. Weiterhin konnte erstmals ein verändertes Anlagerungsverhalten eines Glykoproteins an Concanavalin A bei bestimmten Erkrankungen nachgewiesen werden. So verliert die Gamma-Glutamyltransferase bei alkoholtoxischer Hepatitis durch vermehrte Neuraminsäurekonzentration am Molekül ihre Con A-Affinität. Mögliche Ursachen der differenten Con A-GGT-Bindungsfähigkeit, sowie der weitere Einsatz affinitätschromatographischer Isoenzymdifferenzierung mit Hilfe von Con A-Sepharose werden diskutiert.
    Notes: Summary In this investigation a new possibility of isoenzyme-differentiation of the gamma-glutamyltransferase (GGT) (EC Nr.2.3.2.2.) was demonstrated by Concanavalin A and Con A-Sepharose. Because of the different sugar content of the glycoproteins distinction between liver- and kidney-GGT is possible. Furthermore it was possible for the first time to show a different precipitation behaviour of one glycoprotein to Concanavalin A in certain diseases. In case of alcoholic hepatitis GGT looses its Concanavalin A-affinity because of increased neuraminic acid concentration. The possible reasons of the different behaviour of the binding affinity of Concanavalin A and Con A-Sepharose and GGT as well as additional use for enzyme-differentiation by Con A-Sepharose affinity chromatography are discussed.
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  • 8
    ISSN: 1432-1440
    Keywords: Glycoproteins ; Glycosyltransferases ; Lectins ; Oncology ; Immunology ; Glycoproteine ; Glycosyltransferassen ; Lectine ; Onkologie ; Immunologie
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Zunehmende chemische und biochemische Kenntnisse über Struktur, Biosynthese und Katabolismus der Glycopteine haben auch neue Einblicke in die Pathobiochemie und klinische Bedeutung der Glycoproteine ermöglicht. Diese werden in der vorliegenden Übersicht zusammenfassend dargestellt. 1. Während der Fetalperiode besitzen die endständigen Kohlenhydratreste der Glycoproteine wichtige Funktionen bei der Zell-Adhäsion, -Fusion und gerichteten Migration. Daneben wird die Rolle der endständigen N-Acetylneuraminsäure (NANA) von Glycoproteinen für die immunologische Toleranz zwischen Mutter und Kind diskutiert. 2. Unter onkologischen Gesichtspunkten wird der Einfluß des Glycoproteinmusters der Plasmamembran für das Tumorwachstum und die Metastasierung beschrieben. Veränderte Glycosyltransferase-Aktivitäten im Serum von Tumorpatienten gewinnen zunehmend an diagnostischer Bedeutung. 3. Durch endständige Kohlenhydratreste von Glycoproteinen wird nicht nur die Immunogenität von Makromolekülen, sondern auch die Immunkompetenz des Organismus beeinflußt. Hierdurch erlangen diese Strukturen sowohl bei der immunologischen Tumorabwehr als auch bei Autoimmunerkrankungen klinische Relevanz. Über Ergebnisse ausgewählter Fachgebiete wird in einer nachfolgenden Übersicht berichtet (Klin. Wochenschr.57, 199 (1979)
    Notes: Summary Increasing knowledge on structure, biosynthesis and catabolism of glycoproteins have given new insights on the patho-biochemical and clinical significance of these macromolecules. The most important results and conclusions are summarized in this review. 1. The terminal sugars of glycoproteins—N-acetylneuraminic acid (NANA) and L-fucose—as well as the penultimate galactose molecule have important functions in cell interaction, adhesion and recognition. Moreover, these carbohydrates mediate the migration and distribution of cells and it is believed that they are essential part of the feto-maternal “immunological barrier”. 2. Evidence indicating that the composition and pattern of plasma membrane glycoproteins is associated with tumour growth and metastatic formation is accumulating. Moreover, the determination of serum glycosyltransferase activity is gaining increasing interest, because the level of theses enzymes is substantially elevated in patients with neoplastic disease. 3. Diseases of the autoimmunosystem are likely linked to a disturbed glycoprotein metabolism. The clinical importance is underlined by studies on immunotherapy of tumours.
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  • 9
    ISSN: 1432-1440
    Keywords: Gluten Gluten-sensitive enteropathy ; HLA ; Lectin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The corn protein gluten causes the gluten-sensitive enteropathy in susceptible persons (HLA-antigens). The diagnosis is made on the basis of the morphological criteria of villous atrophy of the jejunal mucosa and the clinical observation that the malabsorption can be healed by a gluten-free diet. The disease, which occurs in children and adults, is a distinct entity. Life-long adherence to a gluten-free diet is difficult. Intentional or unintentional reintroduction of gluten often causes masked disease states. These are best classified on the basis of electron-microscopy study of the jejunal biopsy. We propose a new classification of the phases of remission. A group of diseases exist which are closely related to gluten-sensitive enteropathy. Frequently villous atrophy is detectable. However, the disease does not respond to a gluten-free diet. The pathophysiology of these diseases is at present unclear. Diseases involving autoimmune processes also appear to be associated with gluten-sensitive enteropathy. The common factor is probably an immuno-genetic defect. This is supported by the existence of common HLA-antigen constellations. Gluten has been characterised in vitro as a lectin with oligomannose specifity. This provides a new pathomechanism for the gluten induced enterocytic destruction.
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  • 10
    ISSN: 1432-1440
    Keywords: Ascites ; Liver cirrhosis ; Plasminogen ; Antiproteases ; Fibrinolysis ; Dexamethasone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Fibrinolysis induced by the infusion of plasminogen activators into the circulation has been shown to cause coagulation disorders in ascites retransfusion. Dexamethasone is known to inhibit the synthesis of plasminogen activators by peritoneal macrophages. We therefore assessed its potential in preventing the occurrence of fibrinolysis by injecting 16 mg dexamethasone intraperitoneally in 10 patients 24 h before ascites retransfusion was performed. In addition, the effect of dexamethasone upon the activity or concentration of several proteases and antiproteases related to coagulation in plasma and ascites was analyzed on 15 occasions. An increase of the activity of plasminogen, α2-antiplasmin, and antithrombin III, and in the concentration of α1-protease inhibitor in ascites was induced by the dexamethasone injection. However, the reaction was not identical in all patients. Those patients having an increase of plasminogen activities of 0.6 CTA U/ml or more did not show signs of fibrinolysis during retransfusion. The results obtained indicate that intraperitoneal injection of dexamethasone decreases the concentration of plasminogen activators in ascites and thereby reduces the risk of coagulation disorders during retransfusion procedures. Since the effect is variable and not sustained, assessment of preoperative plasminogen concentrations is mandatory in order to prevent complications.
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