Phosphoric acid concentration affects dentinal MMPs activity.

OBJECTIVES: To evaluate whether the concentration of phosphoric acid (PA) has an effect on the proteolytic activity of sound human demineralized dentin. It is hypothesized that the activity of matrix-bound and extracted enzymes depends on the PA concentration used to demineralize dentin. METHODS: One-gram aliquots of mid-coronal human dentin powder were demineralized with 1wt%, 10wt% and 37wt% PA. Concentrations of released calcium were measured for each set of demineralization. Extracted MMP-2 was immunologically identified by western blot and its activity was determined by conventional gelatin zymography. Analysis of released hydroxyproline (HYP) and in situ zymography were performed to evaluate the activity of insoluble, bound-matrix enzymes. RESULTS: The amount of released calcium from dentin powder treated with 37wt% PA was significantly higher (p≤0.05) than that obtained by dentin demineralization with 10wt% and 1wt% PA. Expression and activity of endogenous enzymes, extracted from or bound to dentin matrix, were detected for all samples regardless of the PA concentration. However, the expression and activity of extracted MMP-2 were significantly higher when dentin was treated with 10wt% PA (p<0.05), followed by 1wt% and 37wt% PA. Similarly, the highest concentration of released HYP (i.e. meaning higher percentage of collagen degradation) and the highest activity in in situ zymography were observed when dentin samples were treated with 10wt% PA (p<0.05). CONCLUSIONS: It was confirmed that PA does not denature endogenous enzymes of dentin matrices, but it may somehow modulate the expression and activity of these enzymes in a concentration-dependent manner. CLINICAL SIGNIFICANCE: Endogenous proteases have been identified and suggested to be responsible for the digestion of dentin matrix when activated by the acidic components of dental adhesives. Proteolytic activity of dentinal MMPs showed to be dependent on phosphoric acid concentration. The clinically-used concentration (37%) does not inhibit MMPs activity, but slows it.

Role of omega-3 polyunsaturated fatty acids in the production of prostaglandin E2 and nitric oxide during experimental murine paracoccidioidomycosis.

There has recently been increased interest in the potential health effects of omega-3 polyunsaturated fatty acids on the immune system. Paracoccidioidomycosis is the most important endemic mycosis in Latin America. Macrophages have a fundamental role and act as first line of organism defense. The purpose of this study was to analyze the effect of n-3 fatty acids on the production of PGE2 and NO by mice infected with Pb18 and fed a diet enriched with LNA for 8 weeks. To study the effect of omega-3 fatty acids on macrophage activity during experimental paracoccidioidomycosis, mice were infected with Pb18 and fed a diet supplemented with LNA. PGE2 in the serum of animals was analyzed and NO in the supernatants of macrophages cultured and challenged in vitro with Pb18 was measured. Omega-3 fatty acids seemed to decrease the production of PGE2 in vivo in the infected group fed an LNA-supplemented diet during the 4th and 8th weeks of the experiment. At the same time, we observed an increase in synthesis of NO by peritoneal macrophages in this group. Omega-3 fatty acids thus appear to have an immunomodulatory effect in paracoccidioidomycosis.

Dermatofibrossarcoma protuberans: tumor hemorrágico de perna esquerda. Relato de caso e revisäo da literatura / Dermatofibrosarcoma Protuberans: hemorragic tumor of the left lower limb, a case report and review of the literature

Os autores relatam um caso de dermatofibrossarcoma protuberans em perna esquerda, cuja manifestaçäo hemorrágica levou à participaçäo do cirurgiäo vascular. Baseado em uma revisäo da literatura, o quadro clínico e o manejo säo discutidos.

Transient platelet aggregation as a mechanism of unstable angina. Aggressive treatment with coronary angioplasty.

Decreased oxygen supply rather than increased demand may be the primary pathogenic mechanism of myocardial ischemia in patients with unstable angina. Coronary artery spasm and in vivo platelet aggregation may play an important role in the mechanism by which the magnitude of fixed obstruction secondary to coronary atherosclerosis is transiently exacerbated. In this case report, we describe a patient who developed chest pain accompanied by ischemic ECG changes during coronary arteriography, due to a transient thrombotic aggravation of a fixed, significant coronary stenosis. Percutaneous transluminal coronary angioplasty was performed with relief of the coronary stenosis and of the symptoms.

Complete and delayed reversal of a large dyskinetic area with early spontaneous reperfusion during evolving myocardial infarction.

Sequential angiographic studies have shown that spontaneous reperfusion occurs in approximately 30 to 40% of patients during evolving myocardial infarction. However, it is difficult to establish the effects of spontaneous reperfusion on left ventricular function. We report the case of a 65 year old woman with clinical features of acute myocardial infarction with early spontaneous reperfusion and complete recovery of ventricular function 1 year later.