Browsing by Author "Sá, P."
Now showing 1 - 3 of 3
Results Per Page
Sort Options
- Corpus cavernosum from men with vasculogenic impotence is partially resistant to adenosine relaxation due to endothelial A(2B) receptor dysfunctionPublication . Faria, M.; Cardoso, T.; Lafuente-de-Carvalho, J.; Sá, P.ABSTRACT Although adenosine has been implicated in penile erection in human males, the receptor subtype responsible for adenosine regulation of human corpus cavernosum (HCC) smooth muscle tone is still a matter of debate. Using selective adenosine agonists and antagonists, we aimed at characterizing the adenosine receptors mediating relaxation of precontracted (with 1 M phenylephrine) HCC strips. HCC specimens were collected from control subjects (organ donors) and from patients with severe vasculogenic erectile dysfunction (ED). In control subjects, adenosine and 5 -N-ethyl-carboxamide adenosine (NECA) fully relaxed HCC. The selective A2A receptor agonist 2-[4-(2-p-carboxy ethyl)phenylamino]-5 -N-ethylcarboxamido adenosine (CGS21680C) produced only a partial relaxation (30–50%) of HCC, which could be further enhanced by simultaneous application of 100 M NECA. The selective A2B receptor antagonist N-(4-acetylphenyl)-2-[4-(2,3,6,7-tetrahydro- 2,6-dioxo-1,3-dipropyl-1H-purin-8-il)phenoxy] acetamida (MRS1706) (10 nM) attenuated NECA-induced relaxation without affecting CGS21680C action. The A2A receptor antagonist 4-{2-[7-amino-2-(2-furyl)[1,2,4]triazolo-[2,3-a][1,3,5]triazin-5- ylamino]ethyl}phenol (ZM241385) (50 nM) consistently reduced the actions of both agonists. In contrast to CGS21680C, NECAinduced relaxation was attenuated when endothelial production of NO and prostanoids was reduced by 100 M NG-nitro-Larginine and 10 M indomethacin, respectively. HCC strips from patients with vasculogenic ED were partially resistant to NECA but kept relaxation to CGS21680C; the remaining effect was sensitive to blockade of A2A receptors with 50 nM ZM241385. Data suggest that adenosine regulates HCC smooth muscle tone through the activation of two receptor populations, CGS21680C-sensitive (A2A) and -insensitive (A2B) receptors, located on smooth muscle fibers and on endothelial cells, respectively. Endothelial dysfunction may be correlated with a loss of adenosine A2B receptor activity in penile vessels from men with vasculogenic ED.
- Increased lung inflammation with oxygen supplementation in tracheotomized spontaneously breathing rabbits: an experimental prospective randomized studyPublication . Machado, H.; Nunes, C.; Sá, P.; Couceiro, A.; Moreira-Silva, A.; Águas, A.BACKGROUND: Mechanical ventilation is a well-known trigger for lung inflammation. Research focuses on tidal volume reduction to prevent ventilator-induced lung injury. Mechanical ventilation is usually applied with higher than physiological oxygen fractions. The purpose of this study was to investigate the after effect of oxygen supplementation during a spontaneous ventilation set up, in order to avoid the inflammatory response linked to mechanical ventilation. METHODS: A prospective randomised study using New Zealand rabbits in a university research laboratory was carried out. Rabbits (n = 20) were randomly assigned to 4 groups (n = 5 each group). Groups 1 and 2 were submitted to 0.5 L/min oxygen supplementation, for 20 or 75 minutes, respectively; groups 3 and 4 were left at room air for 20 or 75 minutes. Ketamine/xylazine was administered for induction and maintenance of anaesthesia. Lungs were obtained for histological examination in light microscopy. RESULTS: All animals survived the complete experiment. Procedure duration did not influence the degree of inflammatory response. The hyperoxic environment was confirmed by blood gas analyses in animals that were subjected to oxygen supplementation, and was accompanied with lower mean respiratory rates. The non-oxygen supplemented group had lower mean oxygen arterial partial pressures and higher mean respiratory rates during the procedure. All animals showed some inflammatory lung response. However, rabbits submitted to oxygen supplementation showed significant more lung inflammation (Odds ratio = 16), characterized by more infiltrates and with higher cell counts; the acute inflammatory response cells was mainly constituted by eosinophils and neutrophils, with a relative proportion of 80 to 20% respectively. This cellular observation in lung tissue did not correlate with a similar increase in peripheral blood analysis. CONCLUSIONS: Oxygen supplementation in spontaneous breathing is associated with an increased inflammatory response when compared to breathing normal room air. This inflammatory response was mainly constituted with polymorphonuclear cells (eosinophils and neutrophils). As confirmed in all animals by peripheral blood analyses, the eosinophilic inflammatory response was a local organ event.
- Spontaneous Dissection of the Renal Artery in Vascular Ehlers-Danlos SyndromePublication . Pereira, F.; Cardoso, T.; Sá, P.Ehlers-Danlos syndrome (EDS) is a rare heterogeneous group of connective tissue disorders. The vascular type (vEDS) is an autosomal dominant disorder caused by heterozygous mutations in the COL3A1 gene predisposing to premature arterial, intestinal, or uterine rupture. We report a case of a 38-year-old woman with a recent diagnosis of vEDS admitted in the Emergency Department with a suspicion of a pyelonephritis that evolved to a cardiopulmonary arrest. A fatal retroperitoneal hematoma related with a haemorrhagic dissection of the right renal artery was found after emergency surgery. This case highlights the need to be aware of the particular characteristics of vEDS, such as a severe vascular complication that can lead to a fatal outcome.