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
    Copenhagen : Munksgaard International Publishers
    Experimental dermatology 9 (2000), S. 0 
    ISSN: 1600-0625
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Mast cells can be found in contact with epidermis in certain circumstances; especially in chronic inflammatory skin diseases and chronic ulcers, but the significance of this association is obscure. In this study, the association of mast cells with wound healing was studied by counting mast cells in the wound edges at different stages after wounding the donor site skin for pinch-grafting. Chronic venous leg ulcers were biopsed for comparison. Tryptase- and chymase-positive mast cells were stained enzyme-histochemically for active proteinases. Both the number of tryptase-positive, i.e. total mast cells, and chymase-positive mast cells decreased during wound healing, but only the change in chymase-positive mast cells was statistically significant (P≤0.03) the maximal decrease being 63% on day 7. No mast cells could be found in the vicinity of epithelialization margin. In venous leg ulcers, significantly more mast cells were present in the perilesional skin near the epithelium margin than in the wound bed (P=0.03), and mast cells were also seen in close contact with the basement membrane. Immunoreactivity for IL-4 and TNF-α in mast cells was studied to see if either of these molecules was associated with wound healing. In normally healing wounds, only a minority of mast cells were immunoreactive for these cytokines and no change in positive mast cell numbers could be seen during wound healing. In chronic wounds, IL-4 was absent in mast cells, and TNF-α positive mast cells were present only in perilesional skin and in small numbers. These results show that mast cells; especially chymase-positive; decrease in number and can not be found in the epithelialization zone in normal wound healing, whereas tryptase-positive mast cells are associated with delayed wound healing and epithelialization in chronic wounds. Thus it seems, that mast cells attempt to control hyperproliferation of epidermis in chronic wounds.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    Experimental dermatology 10 (2001), S. 0 
    ISSN: 1600-0625
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Mast cells are suggested to participate in regenerative processes, but their influence on epithelialization and wound healing has not been well studied. Since mast cells can be found in contact with epidermis in chronic inflammatory skin diseases and venous ulcers, the effect of mast cells on keratinocyte growth was studied. Keratinocytes were cultured in serum-free conditions with (complete medium) or without (basal medium) epidermal growth factor (EGF) and bovine pituitary extract (BPE) to reach subconfluence in a 24-well plate, and the cells were treated with different mast cell mediators histamine, heparin and tryptase, or lysate from HMC-1 cells, a human leukemic mast cell line. Whole skin cultures were used as a model for in vitro wounds to study the effect of mast cells on epithelial outgrowth from skin specimens. Histamine inhibited 3H-thymidine incorporation of keratinocytes dose-dependently by 29% at 1 mM, and 89% at 5 mM histamine. In whole skin culture, histamine inhibited epithelial outgrowth dose-dependently by 64% already at 0.1 mM histamine and maximally (91%) at 1 mM histamine. Heparin inhibited 3H-thymidine incorporation dose-dependently by up to 33% at 2 μg/ml in the absence, but not in the presence, of EGF/BPE. In contrast, in whole skin culture, heparin first inhibited the epithelial outgrowth by up to 27% at 2 μg/ml, but then reversed the inhibition to 30% stimulation at 200 μg/ml. Skin tryptase (0.0285 to 2.85 μg/ml) with or without heparin (0.5 to 20 μg/ml) did not affect thymidine incorporation in keratinocytes. Lysate from HMC-1 cells, but not that from control, neuroblastoma cells, inhibited 3H-thymidine incorporation in keratinocytes dose-dependently, and maximal (47%) inhibition was reached with 16,700 lysed HMC-1 cells/ml. In whole skin culture, HMC-1 lysate inhibited the epithelial outgrowth by up to 36% at 67,000 lysed cells/ml. The results show that mast cells and their mediators are inhibitory to keratinocyte 3H-thymidine incorporation and epithelial outgrowth in vitro, although, the inhibitory effect of histamine was seen at high concentrations suggesting a requirement for close morphologic vicinity of mast cells to keratinocytes. Thus, mast cells are assumed to control epidermal regeneration and to impair epithelialization of chronic ulcers.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    British journal of dermatology 152 (2005), S. 0 
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background  Numerous mast cells are present in chronic leg ulcers. Tryptase and chymase are the major mediators of mast cells, but their significance is mostly dependent on their activity. In addition, the proteinases may affect ulcer epithelialization.Objectives  To study levels and activity of tryptase and chymase in wash samples and biopsies from chronic leg ulcers and the possible effect of these proteinases on keratinocyte growth and adherence.Methods  Wash samples were taken from 16 patients and a superficial shave biopsy was taken in eight of these patients; a second biopsy series was obtained from the edge of chronic venous leg ulcers (n = 6).Results  Significant levels of soluble tryptase activity and histamine, but low levels of chymase activity, were measured in wash samples from chronic ulcers. No tryptase-inhibiting activity, but clear chymase-inhibiting activity, was detected in the wash samples. In superficial wound bed biopsies, relatively marked levels of chymase activity together with histamine and tryptase activity were detected. In the second biopsy series, about 80% of the mast cells belonged to the MCTC type (tryptase- and chymase-immunopositive). However, about 55–61% of the chymase-immunopositive cells displayed chymase activity and 64 ± 17% of the tryptase-positive cells revealed immunoreactivity of α1-antichymotrypsin. As the activity of chymase and tryptase was detected in the ulcer base in a ratio of 1 : 8, a preparation containing both chymase and tryptase was partially purified from human skin yielding a similar activity ratio of 1 : 11–13. Treatment of fibronectin-coated plastic surfaces with this preparation decreased the adherence of cultured human keratinocytes, this effect being attributable mainly to chymase. In 2-day cultures using growth factor/serum-deficient low- or high-calcium medium, the tryptase–chymase preparation inhibited the slow growth and at higher concentrations it even induced detachment of keratinocytes. This effect was attributed to chymase, and it was partially regulated by heparin and histamine.Conclusions  Even though chymase is partially inactivated in chronic leg ulcers, accumulated mast cells in the close proximity of the epithelium edge and their chymase may impair keratinocyte adherence and migration.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Journal of Steroid Biochemistry 5 (1974), S. 655-658 
    ISSN: 0022-4731
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Journal of Steroid Biochemistry 17 (1982), S. xli 
    ISSN: 0022-4731
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 0165-7992
    Keywords: Automation ; Biphenyl derivatives ; Flourenone derivatives ; Mutagenicity ; Phenanthrenequinone derivatives ; SOS response
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , 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
    Acta neurochirurgica 17 (1967), S. 24-31 
    ISSN: 0942-0940
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die zerebrale Zirkulation bei Kaninchen wurde durch fortlaufende Registrierung des zerebro-venösen Sauerstoffdruckes gemessen. Der intrakranielle Druck wurde auf hydrostatische Weise durch einen in den lumbalen Subarachnoidalraum eingeführten Katheter erhöht. In den hier dargestellten Versuchen wurden sehr hohe Drucke, im allgemeinen um 140 mmHg, untersucht. Dabei wurde festgestellt, daß die meisten Versuchstiere selbst bei so hohen Drucken ihre Hirndurchblutung für einige Zeit verhältnismäßig gut aufrecht erhalten konnten und daß die Toleranz durch Infusion vasopressorisch wirkender Pharmaka verbessert werden konnte. Periodische Atmung und Schwankungen des Blutdruckes schienen anzuzeigen, daß das Tier die Grenze seiner Toleranzfähigkeit erreicht hatte. Wenn die intrakranielle Drucksteigerung beendet wurde, stieg der Sauerstoffdruck in den zerebralen Venen oft höher als vor Beginn der Drucksteigerung; unter Berücksichtigung der Arbeit vonHäggendal, Löfgren, Nilsson undZwetnow (1966) spricht dieses wahrscheinlich für eine zerebrale Hyperämie.
    Abstract: Résumé La circulation cérébrale chez les lapins fut contrôlée par un enregistrement continu de la tension de l'oxygène dans les veines cérébrales (PcvO2). La tension intracranienne fut augmentée en appliquant une pression hydro-statique au moyen d'un cathéter introduit dans l'espace sous-arachnoidien. Dans les expériences rapportées des tensions très hautes, en général 140 mmHg, ont été réalisées. Dans la plupart des cas les animaux d'expérience pouvaient maintenir leur circulation cérébrale relativement bien pendant quelque temps, même avec une si haute pression et leur tolérance pouvait être élevée par la perfusion de «vasopresseurs». La respiration périodique et les oscillations de la pression sanguine semblaient indiquer que l'animal avait atteint sa limite de tolérance. Quand l'hypertension intracranienne fut supprimée le PcvO2 montait souvent plus haut qu'avant. D'après l'étude deHäggendal, Löfgren, Nilsson etZwetnow (1966), ceci indique vraisemblablement une hyperémie·cérébrale.
    Notes: Summary The cerebral circulation in rabbits was monitored by continuous recording of the cerebral venous oxygen tension (Pcvo2). The intracranial pressure was raised by applying hydrostatic pressure through a catheter introduced into the lumbar subarachnoid space. In the experiments reported here, very high pressures, generally 140 mmHg, were investigated. It was found that in most cases the experimental animals could maintain their cerebral circulation reasonably well for some time, even with such high pressures, and that their tolerance could be raised by infusion of vasopressors. Periodic breathing and oscillations in blood pressure seemed to indicate that the animal had reached its limit of tolerance. When the application of high intracranial pressure was stopped, the Pcvo2 often rose higher than before the application of pressure; considering the report ofHäggendal, Löfgren, Nilsson, andZwetnow (1966) this presumably indicated cerebral hyperaemia.
    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...