Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Diabetologia 1 (1966), S. 201-207 
    ISSN: 1432-0428
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Ce travail présente une simplification de la méthode de la mesure de l'activité insulinique sérique basée sur l'oxydation du glucose-1-14C par le tissu adipeux. Avec cette méthode deux personnes peuvent procéder à 40 dosages en une journée en utilisant deux rats seulement. L'index de précision est de l'ordre de 0,13. L'application de la méthode à la mesure de l'activité insulinique du sérum humain dialysé révèle la présence de 78 à 1020 μU/ml (465 ± 68 μU/ml). Environ 40% de cette activité insulinique totale s'est révélé être supprimable par l'adjonction d'anticorps anti-insuline purifiés à partir de sérum de cobaye. Les mêmes résultats ont été obtenus tant pour le sérum humain obtenu à jeun et dialyse que pour des extraits éthanoliques de ces sérums. Lorsqu'on reporte graphiquement la radioactivité du14CO2 produit en proportion de la dilution du sérum, on n'observe pas une augmentation de l'activité insulinique résultant de cette dilution. Par contre, une augmentation est observée lorsqu'on rapporte non pas directement la radioactivité du14CO2 mais l'activité insulinique correspondante obtenue par comparaison avec des courbes standards dans un tampon. Ceci paraît dû au fait que la pente des courbes standards d'insuline obtenues en présence de sérum est plus faible que celle des courbes obtenues dans le tampon de Krebs-Ringer.
    Abstract: Zusammenfassung In vorliegender Arbeit wird eine vereinfachte, auf der Stimulation der 1-14C-Glucose-oxydation beruhende Fettgewebsmethode zur Insulinbestimmung im Serum beschrieben. Zwei Personen können an einem Tag 40 Einzelbestimmungen durchführen, wofür nur zwei Ratten benötigt werden. Der Präzisionsindex liegt bei 0.13. Die Anwendung der Methode auf die Bestimmung der gesamten Insulinaktivität in dialysierten menschlichen Nüchternseren ergab Beträge von 78 — 1020 μE/ml (M = 465±68 μE/ml). Mit angereicherten Insulinantikörpern aus Meerschweinchenserum waren etwa 40% der gesamten Insulinaktivität hemmbar. Dies wurde sowohl in dialysierten menschlichen Nüchternseren, als auch in HCl-Äthanolextrakten aus Serum gefunden. Eine Zunahme der Insulinaktivität durch Serumverdünnung ist nicht zu beobachten, wenn man die Radioaktivität des entwickelten14CO2 gegen fallende Serumkonzentrationen aufträgt. Eine Aktivitätssteigerung wird jedoch vorgetäuscht, wenn die Impulse über eine Krebs-Bicarbonat-Ringerlösung-Insulin-Eichkurve in μE umgewandelt werden. Der Grund hierfür ist darin zu suchen, daß die Insulineichkurven in Anwesenheit von Serum flacher verlaufen, als in serumfreier Krebs-Bicarbonat-Ringerlösung.
    Notes: Summary The present study presents a simplified method for the measurement of insulin-like activity through its effect on stimulation of glucose-1-14C oxidation by adipose tissue. Forty determinations can be carried out by two persons in a single day and only two rats are required. The index of precision is in the neighbourhood of 0.13. When the method was applied to the measurement of total insulin-like activity in dialyzed human serum obtained from fasting subjects, the results obtained varied between 78-1020 μU/ml (465 ± 68 μU/ml). Approximately 40 per cent of the total insulin-like activity was suppressible in the presence of insulin antibodies partially purified from guinea pig serum. This was true both for dialyzed serum from fasting subjects and for acid ethanol extracts of serum. There was no increase in the insulin-like activity of serum upon dilution, provided that the radioactivity of the14CO2 formed was directly plotted against the decreasing serum concentrations. A fictitious increase in the insulin-like activity was obtained, however, when the radioactivity was transformed into insulin equivalents by comparison with a standard curve in buffer. It would seem that this is the result of the observation that insulin standard curves in the presence of serum are flatter than is the case in Krebs-Ringer buffer.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Diabetologia 1 (1965), S. 21-27 
    ISSN: 1432-0428
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Au cours de perfusions de foie isolé de rat, les auteurs décrivent, pendant des périodes allant jusqu' à six heures, la formation d'une substance hépatogène capable de stimuler l'oxidation de glucose-1 —14C en14CO2 par la graisse épididymaire de rat. Cette substance a donc une activité de type insulinique (≪ILA hépatique≫), mais cette activité n'est pas supprimée par l'adjonction d'anticorps anti-insuline obtenus chez le cobaye. La formation de cette ILA hépatique ne nécessite pas la présence d'insuline pancréatique exogène dans le milieu de perfusion et n'est donc pas l'insuline pancréatique exoène modifiée. Son activité ressemble à celle de l' ≪ILA non supprimable≫ du sérum humain. La production de cette substance par le foie perfuse est suffisamment active pour qu'il soit possible d'admettre qu'elle contribue peut-être à la formation de l'activité insulinique nonsupprimable du sérum et donc à sa persistance après pancréatectomie. Le rapport fait également état (Tableau 2) d'une activation thermique de l'effet biologique de solution d'insuline dans un tampon bicarbonate.
    Abstract: Zusammenfassung Die isolierte Rattenleber gibt bei Durehströmung bis zu 6 Stunden eine Substanz an das Medium ab („hepatische ILA”), die wie Insulin die Glukose-1 —14C — Oxydation durch das Rattennebenhodenfettgewebe stimuliert, jedoch durch Insulinantikörper aus Meerschweinchenserum nicht unterdrückbar ist. Die hepatische ILA ist nicht an die Zufuhr von Pankreasinsulin gebunden, stellt also kein Umwandlungsprodukt von freiem Insulin dar. Sie ähnelt in ihren Eigenschaften der nichthemmbaren Serum-ILA des Menschen. Entsprechend der Bildungsrate hepatischer ILA im Perfusionsversuch könnte die Leber quantitativ einen maßgeblichen Beitrag zur Aufrechterhaltung der nichthemmbaren Serum-ILA liefern. Im Zuge der vorliegenden Untersuchungen wurde außerdem beobachtet, daß die biologische Aktivität von Rinder-Kristallinsulin durch kurzes Erwärmen im Bicarbonatpuffer zunimmt (Tabelle l). Der Effekt beruht möglicherweise auf einer thermischen Dissoziationdes Insulins in Untereinheiten.
    Notes: Summary Perfusion of isolated rat liver for periods up to six hours resulted in the steady release of a substance — of hepatic origin — which stimulates the oxydation of glucose-1 —14O to14CO2 by rat epididymal adipose tissue. The activity of the substance, therefore, resembles that of insulin (“hepatic ILA”); however, the activity is not suppressed by the addition of antiinsulin antibodies obtained in guinea pigs. This hepatic ILA is released whether or not pancreatic insulin is added to the circulating medium and thus does not represent a metabolite of added pancreatic insulin. It has properties similar to those of “non-suppressible” ILA of human serum. The rate of production of hepatic ILA in the perfused rat liver is sufficient to warrant consideration of its contributing to a major extent to the maintenance of serum levels of “non-suppressible” ILA, particularly in pancreatectomized animals. Also described in this paper is an activation of the biologic activity of crystalline insulin as a result of heating in bicarbonate buffer (Table 1) and it is suggested on the basis of ultracentrifugation studies that this might be the result of “disaggregation” of insulin into smaller units.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1432-0428
    Keywords: Diabetes control ; glycosyl-albumin ; haemoglobin A1a−c ; non-enzymatic glycosylation ; diabetic ketoacidosis ; hyperglycaemia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Glycosylated haemoglobin (HbA1a−c) and serum albumin (glycosyl-albumin) have been determined in patients with severe diabetic ketoacidosis and non-acidotic coma. Within one week of therapy the level of glycosyl-albumin decreased from 184 mmol 5-hydroxymethylfurfural (HMF)/mol albumin to 152 mmol HMF/mol albumin (p〈0.01) and was gradually lowered by some 40% during a period of 17 days. In contrast, the level of HbA1a−c remained unchanged. From these observations and findings in a patient with insulinoma, it appears that glycosyl-albumin provides a more acute measure of variation in relative glycaemia than HbA1a−c, and may prove useful as a measure of medium-term diabetes control.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1432-0428
    Keywords: Insulin ; pyruvate dehydrogenase ; enzyme interconversion ; heart muscle ; alloxan-diabetes ; heart perfusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Evidence is presented for regulation by insulin of pyruvate dehydrogenase (PDH) interconversion in rat heart muscle in vivo and in vitro. In the alloxan diabetic rat the active (dephospho) enzyme amounted only to 12% of total PDH and was restored to 42% by insulin. Antilipolytic treatment of the diabetic animals was ineffective, indicating that the action of insulin was independent of a lowering of plasma non-esterified fatty acid concentration. On perfusion of isolated hearts from diabetic rats in the presence of glucose the proportion of pyruvate dehydrogenase in the active form remained low but was fully restored upon addition of insulin (2 mU/ml) to the medium. No effect of insulin was obtained in the absence of glucose. The correlation between the rate of pyruvate decarboxylation in the perfused heart and of pyruvate dehydrogenase activity, in vitro, suggests that in the diabetic heart the entry of pyruvate into the citric acid cycle is largely controlled by covalent modification of the pyruvate dehydrogenase complex rather than by feedback inhibition. The possible role of insulin therein is discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Diabetologia 10 (1974), S. 439-447 
    ISSN: 1432-0428
    Keywords: Localization ; insulin ; fat cell ghost ; insulin receptor ; ferritin-antiinsulin conjugate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The localization of insulin on the surface of fat cell ghosts, incubated at physiological concentrations of the hormone, was tested with ferritin labelled insulin antibodies. Insulin binding sites, as revealed by this approach, were found to be uniformly distributed around ghost membranes. About 20% of the number of vesicles or 15% of the membrane surface area of a ghost preparation was tagged with ferritin. No ferritin labelling was observed when insulin was omitted from the reaction mixture or when it was replaced by proinsulin, insulin A and B chain, glucagon, ACTH or oxytocin. The membranes were also devoid of ferritin when the antiinsulin conjugate was substituted by unspecificγ-globulin conjugate. The insulin binding sites demonstrated by the immunoferritin technique resembled the insulin receptor of fat cell membranes in so far as they showed trypsin sensitivity, heat lability and temperature dependency of insulin dissociation. From the distance between the ferritin particles and the membrane surface it appears that the insulin binding sites are located very close to or within the ghost membrane. The number of ferritin particles on individual membranes per unit area was higher than the number of insulin receptors calculated from the data of insulin binding studies on the basis of equal distribution of the receptor sites.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Annals of hematology 11 (1965), S. 309-311 
    ISSN: 1432-0584
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Annals of hematology 1 (1955), S. 295-297 
    ISSN: 1432-0584
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 1432-0584
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Annals of hematology 12 (1966), S. 352-357 
    ISSN: 1432-0584
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...