Biomedical subjects

L Mugnai

Publications and source records attributed to L Mugnai.

4 recordsLinked to original sources

PubMed1991

The effect of nitric oxide generators on ischemia reperfusion injury and histamine release in isolated perfused guinea-pig heart.

Experiments were carried out to provide evidence of the effect of L-arginine (L-Arg), its analogue NG-monomethyl-L-arginine (MeArg) and of some nitrovasodilators (sodium nitroprusside, NaNP; 3-morpholino-sydnonimine, SIN-1) which spontaneously release nitric oxide (NO) on ischemia-reperfusion injury, histamine release and mast cell degranulation, occurring after multiple ligature and release of the left anterior descending (LAD) coronary artery in isolated perfused guinea-pig hearts. The reopening of the LAD coronary artery leads to a release of histamine related to a decrease in microdensitometry of cardiac mast cells and to calcium overload. The perfusion of the heart with NO-donors significantly reduces either the release of histamine, the loss of mast cell metachromasia and the overload of calcium. These effects were potentiated by SOD. The results suggest that the endogenous formation of NO and molecules able to generate NO have a role in the prevention of post-ischemic tissue injury.

Animals↗

PubMed1991

Effects of nucleus basolateralis amygdalae neurotoxic lesions on aversive conditioning in the rat.

After bilateral stereotaxic administration of ibotenic acid on the n. basolateralis amygdalae, male adult rats were tested in the light-dark box apparatus to measure the time-course of the acquisition and retention of passive and active avoidance responses. The results show that after the lesions both passive avoidance and active avoidance acquisition were impaired. Passive avoidance responses were retained quite well, while active avoidance responses disappeared quickly. Conditioned freezing was almost completely absent. Thus it appears that the n. basolateralis plays a facilitatory role in all the conditioned responses which were investigated.

Amygdala↗

PubMed1991

Effect of nitric oxide generators on ischemia-reperfusion injury and histamine release in isolated perfused guinea pig heart.

In an ischemia-reperfusion model obtained in isolated perfused guinea pig heart by means of a double ligature of the left anterior descending coronary artery, the reperfusion of the ischemic myocardium leads to a release of lactate dehydrogenase and histamine, related to a decrease in the microdensitometry of cardiac mast cells and to a tissue calcium overload. The perfusion of the heart with L-arginine and with nitric oxide donors significantly reduces the release of histamine, the loss of mast cell metachromasia and calcium overload. These effects were potentiated by superoxide dismutase.

Animals↗

PubMed1991

Mast cell fixation and staining in image analysis.

Modern image analysers automatically perform densitometric measurements and elaborate digital images. Elaboration however is subject to operator interpretation and often eliminates precious information from the areas of interest. For this reason, it was appropriate to find a staining method which would overcome this drawback and, in the case of mast cell histochemistry, limit staining to granule content. The following current staining techniques were tested: Toluidine Blue in buffered solution (solut. a) and in 0.003% alcoholic solution (solut. b) and alcoholic Astra Blue, pH 0.2 Densitometric analysis was performed on both 5 microns and semithin sections of mouse tongue fixed in Isotonic formaldehyde-acetic acid (IFAA). Digital images were obtained using 630 nm and 546 nm wavelengths for Toluidine Blue and 610 nm for Astra Blue. Direct comparison between the two Toluidine Blue solutions revealed that more pixels were captured by the 5 microns sections stained with solut. a, whilst the opposite occurred in semithin sections. Both dyes introduced a certain amount of error due to the orthochromatic component of the nucleus and cytoplasmic basophily, which had to be eliminated through image elaboration. Because of its subjective nature, this operation may in turn lead to further errors. The choice of Astra Blue as an alternative to Toluidine Blue in densitometric analysis of mastocytes is based on its property to restrict staining to the granules of mast cells. A comparison between Astra Blue and the two Toluidine Blue solutions showed that, at all transmission levels, preparations stained with Astra Blue captured more pixels than those stained with Toluidine Blue. Consequently our results suggest that the most suitable technique for densitometric image analysis is fixation of mast cells in IFAA followed with Astra Blue.

Animals↗