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  • 1
    ISSN: 1432-0428
    Keywords: Insulin receptor isotypes ; Type 2 (non-insulin-dependent) diabetes mellitus ; insulin receptor antibody
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The human insulin receptor exists in two isoforms (HIR-A α-subunit 719 amino acids and HIR-B α-subunit 731 amino acids) which are generated by alternative splicing of a small exon and display distinct patterns of tissue-specific expression. Using the polymerase chain reaction we have recently shown that skeletal muscle of non-diabetic individuals contains predominantly mRNA encoding HIR-A while in skeletal muscle derived from subjects with Type 2 (non-insulin-dependent) diabetes mellitus similar amounts of each mRNA are expressed. We used a polyclonal antibody which discriminates between HIR-A and HIR-B to assess the isoform expression at the protein level. The antibody showed clearly distinct displacement of insulin binding in skeletal muscle membranes of non-diabetic subjects compared to Type 2 diabetic subjects (displacement of specific 125I-insulin binding: 13 non-diabetic subjects 70.0%±14.34, 12 Type 2 diabetic subjects 32.6%±17.45). A control antibody which does not discriminate between both isoforms showed similar displacement of 125I-insulin in membranes of non-diabetic and Type 2 diabetic subjects. These data suggest that the altered expression of receptor isotype mRNA in the skeletal muscle of Type 2 diabetic subjects leads to an altered receptor isoform pattern in the plasma membrane. While skeletal muscle membranes of non-diabetic subjects contain predominantly HIR-A, membranes of Type 2 diabetic subjects show an increased level of HIR-B in addition to HIR-A.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0428
    Keywords: Glucose transporter ; human skeletal muscle ; Type 2 diabetes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Insulin resistance of the skeletal muscle is a key feature of Type 2 (non-insulin-dependent) diabetes mellitus. To determine whether a decrease of glucose carrier proteins or an altered subcellular distribution of glucose transporters might contribute to the pathogenesis of the insulin resistant state, we measured glucose transporter numbers in membrane fractions of gastrocnemius muscle of 14 Type 2 diabetic patients and 16 non-diabetic control subjects under basal conditions. Cytochalasin-B binding and immunoblotting with antibodies against transporter-subtypes GLUT 1 and GLUT 4 were applied. The cytochalasin-B binding values (pmol binding sites/g muscle) found in a plasma membrane enriched fraction, high and low density membranes of both groups (diabetic patients and non-diabetic control subjects) suggested a reduced number of glucose transporters in the plasma membranes of the diabetic patients compared to the control subjects (diabetic patients: 1.47 ± 1.01, control subjects: 3.61 ± 2.29,p ≤ 0.003). There was no clear difference in cytochalasin-B binding sites in high and low density membranes of both groups (diabetic patients: high density membranes 3.76 ± 1.82, low density membranes: 1.67 ± 0.81; control subjects: high density membranes 5.09 ± 1.68, low density membranes 1.45 ± 0.90). By Western blotting analysis we determined the distribution of the glucose transporter sub-types GLUT 1 and GLUT 4 in the plasma membrane enriched fraction and low density membranes of seven patients of each group. In agreement with the cytochalasin-B binding data and despite a high variance within one group, the results show a clear decrease of GLUT 4 in the plasma membrane enriched fraction of diabetic patients compared to control subjects. In contrast, we found no difference in the distribution of GLUT 1 in diabetic patients and control subjects. In conclusion, despite a high variance of glucose transporter numbers in the skeletal muscle of different individuals fractionation of muscle samples clearly suggests that the number of GLUT 4 is reduced in the plasma membrane fraction of skeletal muscle of lean diabetic patients in the basal state.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 32 (1975), S. 9-19 
    ISSN: 1432-0533
    Keywords: Centronuclear Myopathy ; Neuromuscular Disorders ; Type-I-Fiber-Atrophy ; “Myotube-Like Structures”
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Report of a case with congenital symmetrical slowly progressive neuromuscular disease. EMG shows signs of neurogenic atrophy together with a predominant myopathic pattern. Muscle biopsy reveals the characteristics of so-called centronuclear myopathy in combination with “myotube-like structures”. Myometric studies show preferential atrophy of type-I-fibres. Biopsy of the sural nerve indicates involvement of the peripheral nerve. The question whether this disease is essentially neurogenic or myopathic, is discussed. Neurogenic origin is given preference.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 53 (1975), S. 641-642 
    ISSN: 1432-1440
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-1440
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 57 (1979), S. 927-936 
    ISSN: 1432-1440
    Keywords: Muscle carnitine deficiency ; “Systemic carnitine deficiency” ; Carnitine palmityltransferase ; Vacuolar myopathy ; Lipid storage myopathy ; Mitochondrial anomalies ; Hereditary metabolic myopathies ; Muskelcarnitinmangel ; „systemischer Carnitinmangel“ ; Carnitin-Palmityltransferase ; vacuoläre Myopathie ; Lipidspeichermyopathie ; Mitochondrienanomalien ; hereditäre metabolische Myopathien
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es wird über zwei Geschwister berichtet, welche im Alter von 8 bzw. 10 Wochen unter den Zeichen einer Ateminsuffizienz bei zunehmender generalisierter muskulärer Schwäche ad exitum kamen. Auf eine zusätzliche Beteiligung des zentralen Nervensystems wies als einziger Befund ein deutlich erhöhtes Liquoreiweiß hin. Die Muskelbiopsie zeigte eine vacuoläre Myopathie. Histochemisch war eine vermehrte Speicherung von Fett, eine gesteigerte Aktivität an mitochondrialen Enzymen sowie geringer eine Glycogenvermehrung in zahlreichen Muskelfasern vor allem vom Typ I nachweisbar. Elektronenmikroskopisch ließ sich eine zum Teil großtropfige Verfettung im Verein mit vermehrten, vergrößerten und abnorm strukturierten Mitochondrien bestätigen. Biochemisch zeigte sich im Muskel, verglichen mit einem Normalkollektiv, ein eindeutiger Carnitinmangel, sowie eine Erhöhung der Carnitin-Palmityltransferaseaktivität. Retrospektiv ist vom klinischen Verlauf her zu vermuten, daß das Krankheitsbild dem sog. „systemischen Carnitinmangel“ zuzuordnen ist, auch wenn einige sonstige klinische Zusatzsymptome (Hepatomegalie, Kardiomyopathie) fehlten und eine Bestimmung von Serum- und Lebercarnitin nicht erfolgte, da die Kinder starben, bevor die Diagnose des Muskelcarnitinmangels bestätigt war. Das klinische Bild dieser beiden letalen Verläufe wird verglichen mit der Kasuistik eines isolierten Muskelcarnitinmangels. Dieses Kind zeigt einen wesentlich benigneren Verlauf einer Muskelerkrankung. Die morphologischen Befunde des Muskels erwiesen sich jedoch als weitgehend identisch. Biochemisch war die Carnitinverminderung des Muskels sogar ausgeprägter, während die Serumcarnitinwerte im Normbereich lagen. Eine Aktivitätssteigerung der Carnitin-Palmityltransferase war hier nicht nachzuweisen.
    Notes: Summary This report deals with two sisters who died with eight, respectively ten weeks under the signs of respiratory failure caused by progressive muscular weakness. Only an elevated cerebrospinal fluid protein was suspicious of an additional disturbance of the central nervous system. Muscle biopsy revealed a vacuolar myopathy. Histochemistry showed lipid storage, increased mitochondrial enzyme activity, and to a lower degree, glycogen accumulation especially in type I muscle fibers. Electron microscopy confirmed elevated lipid content in combination with increased, enlarged and abnormally structured mitochondria. Biochemical studies on muscle biopsy, in comparison with normal children, showed a significant decrease of carnitine content and an increased activity of carnitine palmityltransferase. Retrospectively from a clinical point of view this disease is suggestive of “systemic carnitine deficiency”, even if some symptoms (hepatomegaly, cardiomyopathy) were not present and serum- and liver carnitine was not measured because the children died before the diagnosis of muscle carnitine deficiency was confirmed. The clinical picture of theese two fatal cases is compared with another observation of muscle caritine deficiency. This child shows only a mild course of muscle disorder, but very similar morphological changes in muscle biopsy. Biochemically, there was a clear decrease in muscular carnitine, while the serum levels were in the normal range. The activity of muscular carnitine palmityltransferase was also normal.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 59 (1981), S. 1053-1059 
    ISSN: 1432-1440
    Keywords: Glycogenosis ; Glycogenosis type V (McArdle) ; Vacuolar myopathy ; Recurrent rhabdomyolysis ; Glycogen storage ; Muscle phosphorylase deficiency ; Glykogenose ; Glykogenose Typ V (McArdle) ; Vacuoläre Myopathie ; Rezidivierende Rhabdomyolyse ; Glykogenspeicherung ; Muskelphosphorylasemangel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es wird über die myopathologischen und biochemischen Befunde von sechs Patienten mit Glykogenose Typ V (McArdle) berichtet. Morphologisch findet sich in vier Fällen das typische Substrat einer vacuolären Myopathie mit vorwiegend subsarkolemmaler Glykogenvermehrung. Eine Biopsie zeigt nur sehr diskrete Strukturveränderungen, welche ohne entsprechende biochemische Befunde keine sichere diagnostische Festlegung zuließen. In einer weiteren Biopsie stehen die Zeichen der abgelaufenen Rhabdomyolyse quantitativ ganz im Vordergrund und überlagern die Speichermyopathie. Biochemisch ist in allen Fällen ein erhöhter Glykogengehalt nachweisbar, welcher mehrheitlich zwischen 2,5–4,23% liegt, bzw. nur bei dem klinisch ausgeprägtesten Fall mit abgelaufener Rhabdomyolyse über 5% beträgt. In allen Fällen kann zusätzlich ein Fehlen bzw. eine hochgradige Verminderung der Phosphorylaseaktivität objektiviert werden. Abgesehen von dem besonders schwer verlaufenden Fall ist keine sichere Korrelation zwischen der Quantität der myopathologischen und biochemischen Befunde zu erkennen, was bedeutet, daß bei entsprechendem klinischen Beschwerdebild eine ergänzende biochemische Untersuchung des Muskels durchgeführt werden sollte, selbst wenn morphologisch nur diskrete Veränderungen zu erkennen sind.
    Notes: Summary This report deals with structural and biochemical studies of muscle biopsies from six patients with glycogenosis type V (McArdle). From a morphological point of view in four cases the typical findings of vacuolar myopathy with glycogen storage especially under the sarcolemma can be demonstrated. One biopsy shows only mild structural changes which without additional biochemical analysis could be overlooked. In one case signs of recovery phase after rhabdomyolysis predominate the storage myopathy. Biochemical studies in all cases show an elevated glycogen content (2.5–4.23%). Only the from a clinical point of view most expressive patient with recurrent episodes of rhabdomyolysis exhibits a glycogen storage over 5%. All cases additionally show an absence or highly reduction of phosphorylase activity. Apart from the most expressive clinical course the extent of morphological and biochemical findings is not clearly correlated. Therefore if clinical signs suggest the diagnosis of glycogenosis type V it appears necessary to perform additional biochemical examination of muscle biopsy independent from the degree of morphological anomalies.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 59 (1981), S. 1195-1199 
    ISSN: 1432-1440
    Keywords: Fallbericht ; Pseudohypoparathyreoidismus ; hypocalcämische Myopathie ; Case report ; Pseudohypoparathyroidism ; Hypocalcemic myopathy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary A patient with the clinical features of pseudohypoparathyreoidism and elevated concentrations of serum CK and LDH, which normalized after successful therapy, is described. Clinical signs of myopathy did not exist. The bioptical material from the m. tibialis anterior was microscopically normal. The biochemical analysis revealed a reduced phosphorylase-a-activity with the total phosphorylase-activity (a and b) being within the normal range. The significance of these findings as well as possible pathogenetic mechanisms are discussed.
    Notes: Zusammenfassung Es wird über einen Fall von Pseudohypoparathyreoidismus berichtet, bei dem gleichzeitig erhöhte CPK- und LDH-Konzentrationen im Serum festgestellt wurden, die sich nach Therapie normalisierten. Klinische Zeichen einer Myopathie bestanden nicht. Das Biopsiematerial vom m. tibialis anterior war mikroskopisch unauffällig. Biochemisch fand sich eine verminderte Phosphorylase-a-Aktivität bei normaler Gesamtphosphorylase-Aktivität (a und b). Die Bedeutung des Befundes und die möglichen pathogenetischen Mechanismen werden diskutiert.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 60 (1982), S. 428-428 
    ISSN: 1432-1440
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 54 (1976), S. 423-430 
    ISSN: 1432-1440
    Keywords: Neuromuscular disorders ; Centronuclear myopathy ; Type I-fiber atrophy ; “Myotubelike structures” ; Neuromuskuläre Erkrankungen ; centronucleäre Myopathie ; Typ I-Faser Atrophie ; “Myotube-like structures”
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es wird über eine Familie berichtet, in welcher sowohl die Mutter, als auch ihre beiden Töchter an einer congenitalen, langsam progredienten neuromuskulären Erkrankung leiden. Die im Rahmen der Muskelbiopsie zu erhebenden histologischen, histochemischen und ultrastrukturellen Befunde zeigen bei der Mutter das Vollbild der sog. centronucleären Myopathie. Die charakteristischen zentralständigen Kerne mit den umgebenden pericentronucleären Strukturanomalien der Fasern werden nahezu in allen Muskelfasern angetroffen. Bei den Töchtern dagegen sind morphologisch fast ausschließlich die Typ I-Fasern befallen, welche zusätzlich im Durchmesser kleiner als normal erscheinen. Der Nachweis dieser beiden Formen von centronucleärer Myopathie in einer Familie beweist, daß hier offenbar zwei morphologische Varianten, wahrscheinlich sogar Stadien eines Krankheitsbildes vorliegen. Das zusätzliche Vorhandensein einiger weiterer struktureller Besonderheiten (rod bodies, core-ähnliche Areale) unterstreicht die Verwandtschaft der Erkrankung mit anderen congenitalen langsam progredienten Myopathien (nemaline myopathy, central core disease).
    Notes: Summary This report deals with a family in which the mother and her two daughters suffer from a congenital, slowly progressive neuromuscular disease. Histological, histochemical and ultrastructural observations of the mother's muscle biopsy reveal the characteristics of the centronuclear myopathy. In this case central nuclei and pericentronuclear abnormalities of muscle fibers are found in almost all fibers. Biopsies obtained of the two daughters show alterations especially of type I-fibers, which often are smaller than normal. The presence of these two forms of centronuclear myopathy in one family indicates that these may be only different morphological types or states of one illness. Additionally, other structural findings (rod bodies, core like regions) emphasize the similarities with other congenital slowly progressive myopathies (nemaline myopathy, central core disease).
    Type of Medium: Electronic Resource
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