Library

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
Filter
  • 1985-1989
  • 1970-1974
  • 1965-1969  (3)
  • 1967  (3)
  • Electron microscopy
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Diabetologia 3 (1967), S. 435-442 
    ISSN: 1432-0428
    Keywords: Plasma insulin ; Pancreatic insulin ; Rabbit ; Pregnancy ; A-cells ; B-cells ; Electron microscopy ; Glucagon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Le contenu en insuline du plasma de lapins normaux et en gestation a été étudié par rapport à la quantité d'insuline qui pouvait être extraite de leurs pancréas. — Le contenu plasmatique moyen en insuline des lapins normaux, utilisés comme témoins, était de 25μU/ml (entre 18 et 33) et l'insuline extraite de leurs pancréas était de 3.56μg/100 mg de tissu (entre 3.33 et 3.76). — Lorsque la gestation était à un stade avancé, le contenu en insuline dans le sang s'élevait à 56μU/ml (entre 37 et 81), alors que l'insuline extraite du pancréas tombait à 1.17μg/100 mg de tissu (entre 0.65 et 1.73). — L'ultrastructure des cellules A et B pendant la gestation a également été étudiée. La teneur des granules B en insuline diminue et les cellules A présentent des signes évidents d'une haute activité. — Les observations précédentes suggéreraient que lors de la gestation avancée, une synthèse et une sécrétion de glucagon accrues augmentent l'activité sécrétrice du pancréas en insuline.
    Abstract: Zusammenfassung Bei normalen und graviden Kaninchen wurden die Plasma-Insulinspiegel und das aus dem Pancreas extrahierbare Insulin gemessen. — Die mittleren Insulinspiegel der normalen Kontrolltiere lagen bei 25μE/ml (zwischen 18–33), das Pankreasinsulin bei 3.56μg/100 mg Gewebe (3.33–3.76). Die Seruminsulin-spiegel steigen während der späten Schwangerschafts-stadien auf 56μE/ml (37–81) an und das extrahierbare Pancreas-Insulin nimmt auf 1.17μG/100 mg Gewebe (0.65–1.73) ab. — Wir untersuchten die Feinstruktur der Alpha- und Beta-Zellen während der Schwangerschaft: Dabei nahm das in den Beta-Granula gespeicherte Insulin ab und die Alpha-Zellen zeigten eindeutige Zeichen gesteigerter Aktivität. Die oben skizzierten Befunde könnten daraufhin deuten, daß während der späten Schwanger-schaftsstadien eine gesteigerte Glucagon-Synthese und Sekretion die insulinsekretorische Aktivität der Bauchspeicheldrüse erhöht.
    Notes: Summary Plasma insulin levels and extractable insulin of the pancreas of normal and pregnant rabbits have been studied. — The mean plasma insulin of non-pregnant controls was 25μU/ml (range 18 to 33); extractable pancreas insulin was 3.56μg/100 mg tissue (3.33 to 3.76). — The insulin level in the blood increases during late pregnancy to 56μU/ml (range 37 to 81) and the extractable pancreatic insulin decreases to 1.17μg/100 mg tissue (0.65 to 1.73). — The fine structure of B and A-cells has been studied in pregnancy: insulin stored in B granules decreases and the A-cells show definite signs of increased activity. — The above findings might be interpreted as suggesting that in late pregnancy an increased synthesis and secretion of glucagon augment the insulin secretory activity of the pancreas.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1432-1106
    Keywords: Deiters' nucleus ; Electron microscopy ; Primary fibres ; Operated cats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Following transection of the vestibular nerve in cats, the electron microscopical changes occurring in the lateral vestibular nucleus were studied after survival periods of 2–11 days. Material for study was taken from the rostroventral part of the nucleus of Deiters since this is known to receive the primary vestibular fibres. Degeneration of terminal boutons is evident two days after the lesion. Degenerating boutons show an increased electron optic density, mitochondrial changes and a loss of synaptic vesicles. They are often surrounded by a pericellular space filled with flocculent (probably protein) material. At three days and later this space is occupied by processes of astrocytes or of a type of phagocytic cells which surround or engulf the degenerating boutons. Nine to eleven days after the lesion almost all degenerating boutons have disappeared. There is evidence of phagocytosis of axons and myelin sheaths by astrocytes but mainly by phagocytes of yet undetermined origin. The “filamentous type” of bouton degeneration has not been observed. Degenerating boutons are found on neuronal perikarya and on proximal as well as on thin distal dendrites and on spines. They are common on small and medium-sized cells, but have also been seen on some giant cells. The degenerating boutons do not form series of synaptic complexes. Degenerating fibres and boutons have so far been found only ipsilateral to the lesion. The findings confirm and extend those made in corresponding experiments with silver impregnation procedures, but emphasize the limitations of the latter methods as regards conclusions concerning synaptic contacts.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1432-1106
    Keywords: Deiters' nucleus ; Electron microscopy ; Purkinje axons ; Operated cats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The present paper is an experimental study on the mode of termination of cerebellar corticovestibular fibres in the cat. The distribution of degenerating terminal structures as this appears in electron micrographs of eight animals with a survival time from three up to eleven days is described. The early stage of degeneration of Purkinje cell axons is a filamentous reaction during which fibres as well as boutons are enlarged and filled with filaments. The initial reaction is followed by shrinkage, and many fibres and boutons are at the 4 day stage electron dense, and no filaments can be recognized. Other fibres and boutons show intermediate stages of degeneration. Only dark degenerating axons and boutons are present at the 11 day stage. The observations are related to those made in other nuclei and regions where degeneration has been described in electron micrographs. Degenerating terminal myelinated fibres ending with terminal and en passage boutons are found. An attempt is made to correlate the findings with those made in normal animals and in Golgi sections. The mode of termination and the pattern of branching of Purkinje cell axons are discussed. The degenerating terminal structures are in synaptic contact with cells of all sizes and with all parts of the neurons, i. e., soma, proximal and distal dendritic trunks and spine-like projections. Elongated and rounded synaptic vesicles are present in the degenerating boutons. The glial reaction adjacent to degenerating boutons is also described, and brief mentioning is made of findings in the intracerebellar nuclei of the same animals. The findings in these nuclei are essentially the same as those made in the lateral vestibular nucleus.
    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...