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
    Basic research in cardiology 79 (1984), S. 440-447 
    ISSN: 1435-1803
    Keywords: myocardium ; ischemia ; infarction ; reperfusion ; pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We investigated the temporal and spatial development of infarcts in porcine hearts to evaluate the time-dependent beneficial effect of reperfusion on infarct size. The left anterior descending coronary artery (LAD) was occluded in 17 pigs for different periods of time followed by 4 hours of reperfusion. Transmural needle biopsies subdivided into subendocardial and subepicardial halves were taken from the ischemic apex after 60 min of ischemia to determine the tissue concentrations of ATP and NAD. The myocardium-at-risk was assessed with a fluorescent dye injected into the right atrium at the end of the experiments, just after the LAD had been reoccluded. The excised hearts were cut into slices parallel to the heart basis. The ischemic myocardium was measured by planimetry of the nonfluorescent areas whereas the infarcted tissue was determined with the NBT stain and related to the area-at-risk. Ischemic cell death started in the jeopardized left ventricular subendocardial septum after about 30 min of ischemia. The further progress involved the right subendocardial septum and the subendocardium of the left anterior free wall. Already after 75 min of ischemia most of the myocytes-at-risk were irreversibly injured. Infarctions reached their final extent after 90–120 min of ischemia. These results indicate that in hearts without a significant collateral blood flow reperfusion can only reduce infarct size if its initiated within 60–75 min of ischemia. Like in canine hearts infarctions progress from the ischemic subendocardium towards the outer layers.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1435-1803
    Keywords: mannitol ; ischemia ; reperfusion ; infarct size ; pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We investigated the effect of reperfusion with hyperosmotic mannitol on the infarct size in porcine hearts. The distal half of the left anterior descending coronary artery was occluded in each of 21 anesthetized pigs for 75 min and was reperfused for 2 h. During reperfusion mannitol (1075 mosmol/kg) was intracoronarily infused at a dose of 0.5 ml/min in 6 pigs (“low” mannitol group), at a dose of 1.5 ml/min in another 6 pigs (“high” mannitol group), and at a dose of 5 ml/min in 3 pigs for the first 8 min of reperfusion (“very high” mannitol group). 6 pigs served as controls. Although mannitol infusion increased plasma osmolality in the ischemic, reperfused myocardium in all experiments, the infarct size expressed as the ratio of the infarcted tissue over the area at risk of necrosis was not significantly influenced. Infarct size amounted to 72±25% in the control group, to 75±14% in the “low” mannitol group, to 78±18% in the “high” mannitol group, and to 93±8% in the “very high” mannitol group. These results clearly indicate that reperfusion with hyperosmotic mannitol after 75 min of ischemia does not exert any beneficial effect on the infarct size.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1435-1803
    Keywords: infarct size ; pig ; residual blood flow ; ventricular fibrillation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The left anterior descending coronary artery was occluded in each of 28 thoracotomized pigs around an intracoronary catheter for periods between 30 and 240 min followed by 90 min of reperfusion. The catheter was connected via an external pump with another arterial catheter. The pump rate was set to deliver 1.5 ml (group I), 3 ml (group II), or 6 ml blood/min (group III) respectively during ischemia. The distribution of the residual blood flow during ischemia was determined in group II with non-radioactive microspheres. We delineated the risk region by a fluorescent dye and the infarcted tissue with a tetrazolium stain. The higher residual blood flow in groups II and III reduced the incidence of ventricular fibrillation during ischemia from 70% (group I) to 28%, suggesting that the amount of residual blood flow is one important determinant for this rhythm disturbance. The subendocardial-subepicardial blood flow ratio in the risk region of the anterior wall was 41%. Infarcts started to develop after 30 min of ischemia (groups I and II). In all groups necrosis progressed most rapidly within the first 90 min of ischemia indicating that besides the beneficial effect of a high residual blood flow only early reperfusion is able to salvage a substantial amount of jeopardized myocardium. Compared to conventional regionally ischemic canine and porcine heart preparations the described model offers the following advantages: Accurate delineation of the risk region, eligible residual blood flow, reduction of ventricular fibrillation with higher residual blood flows, and the possibility to selectively test the metabolic influence of drugs on ischemic injury while avoiding systemic effects.
    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...