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R Perotti

Publications and source records attributed to R Perotti.

At least 19 recordsLinked to original sources
PubMed1995

[Variation, over time, in the pH of the materials used for pulpal-dentinal protection. A new measurement method].

A modern AmpHel pH-meter permits the easy determination of dental materials pH. This new instrument has allowed, analysing seven cements and two varnishes used for pulpodentinal protection, continuously to specify this important parameter's modifications in the long run. The results of this study, conducted for six hours after cement mixing or varnishes application, certified glass ionomer cements' (Ketac-Cem, Fuji-Ionomer II) strong acidity, even higher than well known zinc phosphates' acidity is. A cavity liner's (Tubulitec) pH from an initial value of 6.07 decreased to 5.04 at sixth hour. On the contrary, much lower were the acidity of a modified ZOE (Temrex) and the one of a cavity varnish (Copalite): both showed a physiological pH from the beginning of the test.

Chemistry, Physical↗
PubMed1994

[Different susceptibilities to the development of nitroglycerin tolerance in the human peripheral venous and arterial circulations].

Aim of the study was to assess the relative susceptibility to the development of nitroglycerin tolerance in the arterial and venous circulation in man and to evaluate the interactions between nitroglycerin and N-acetylcysteine. Twenty patients with coronary artery disease underwent a continuous 24-h nitroglycerin infusion followed by a bolus administration of N-acetylcysteine. Forearm blood flow (ml/100 ml/min) and venous volume (ml/100 ml) were measured by strain gauge plethysmography under control conditions, at the end of nitroglycerin titration, after 24 h of infusion and after N-acetylcysteine; vascular resistance was calculated as mean cuff blood pressure/flow. After 24 h of nitroglycerin infusion, the initial increase in venous volume was reduced by 48% (p < 0.01), while the acute effects on vascular resistance were not attenuated in the whole group. N-acetylcysteine restored nitroglycerin venodilator effects in all 10 patients who developed venous tolerance but did not change significantly vascular resistance in 5 patients in whom attenuation of the arterial effects was observed during the infusion period. In conclusion, the results indicate that the susceptibility to the development of nitrate tolerance in man is higher in the venous than in the arterial circulation and that the sulphydryl group donor N-acetylcysteine is more effective in reversing nitroglycerin tolerance in the venous than in the arterial circulation.

Acetylcysteine↗
PubMed1994

[Percutaneous approach in the use of subclavian vein in pacemaker implantation].

BACKGROUND AND METHODS: We analyzed the complications of 1729 pacemakers implants (from October 1980 to December 1992) divided according to the way of leads insertion. The approaches from the subclavian vein was used in 1220 cases, the cephalic vein was used in 431 implants and the external jugular vein in 78. RESULTS: Major complications were: pocket bleeding (108 cases), pocket erosion (15 cases), infection (2 cases), lead fracture (5 cases), lead dislodgement (20 cases), pneumothorax (4 cases, only for subclavian puncture). There were no significative differences in the complications between the three approaches. On the other hand, the subclavian puncture reduces the time of the procedure, is less traumatic and allows to insert and to position several leads. CONCLUSIONS: We suggest to use the subclavian vein approach as first choice to implant one or more leads, being this way safe and fast.

Evaluation Studies as Topic↗
PubMed1992

Different susceptibility to the development of nitroglycerin tolerance in the arterial and venous circulation in humans. Effects of N-acetylcysteine administration.

BACKGROUND: Tolerance to the effects of organic nitrates develops rapidly during continuous exposure to these drugs; its main mechanism seems to be an intracellular sulfhydryl group depletion. However, the relative susceptibility to the development of nitroglycerin tolerance of the arterial or venous circulation in humans is still a matter of dispute. METHODS AND RESULTS: Twenty patients with coronary artery disease underwent a continuous 24-hour nitroglycerin infusion followed by a bolus administration of N-acetylcysteine. Forearm blood flow (ml/100 ml/min) and venous volume (ml/100 ml) were measured by strain gauge plethysmography under control conditions, at the end of nitroglycerin titration, after 24-hour infusion, and after N-acetylcysteine; vascular resistance was calculated as mean cuff blood pressure divided by flow. After 24 hours of nitroglycerin infusion, the initial increase in venous volume was reduced 48% (p less than 0.01), whereas the acute effects on vascular resistance were not attenuated in the whole group. N-Acetylcysteine completely restored nitroglycerin venodilator effects in all 10 patients in whom attenuation of the venous effects was observed during the infusion period. CONCLUSIONS: The data indicate that the susceptibility to the development of nitrate tolerance in humans is higher in the venous than in the arterial circulation, and that the sulfhydryl group donor N-acetylcysteine is extremely effective in reversing nitroglycerin tolerance in the venous circulation in humans.

Acetylcysteine↗
PubMed1992

[A weight and surface analysis of glass ionomer cements in the presence of acid solutions].

The surface and solubility of some glass ionomer cements have been assessed after exposure to four acids (acetic, formic, lactic and propionic), that are usually present in the bacterial plaque. Therefore, we prepared 80 samples--20 for earl of 4 commercial products; after 7 days and, then after 30 other days, the samples were examined by microscope and weighed. Finally, those showing the most significant modifications were photographed.

Acetates↗
PubMed1991

[Hemodynamic benefits of sequential atrioventricular pacing].

The purpose of this study was to evaluate the hemodynamic benefits of atrioventricular (A-V) sequential pacing. 30 pts implanted with DDD pacemakers underwent M-mode, B-mode and Doppler echocardiography. In each patient, left ventricular (LV) stroke volume was assessed by measuring the time-velocity integral of mitral inflow in the following modes and rates: VOO at 70 ppm or at the minimum stimulation rate and at 120 ppm; DOO at the same rates with different A-V delay (100, 150, 200, 250 and, whenever possible, 300 msec). The increase in stroke volume obtained with dual chamber pacing at the optimal A-V delay was 45 +/- 25% at 75 ppm and 29 +/- 14% at 120 ppm (p less than 0.05 75 vs 120 ppm). This increase was significantly higher in pts with than in pts without LV hypertrophy (respectively: 51.9 +/- 20.4 vs 36.9 +/- 20.8% at 75 ppm, p less than 0.05 and 33 +/- 13.4 vs 25.4 +/- 14.5% at 120 ppm, p = 0.08). Concerning the A-V delay, we noted that at 75 ppm stroke volume was significantly higher in DOO than in VOO with any A-V delay ranging +/- 100 msec from the optimal one; at 120 ppm the hemodynamic benefit of DOO pacing was observed only when the programmed A-V delay was the optimal one or very near to it. In conclusion, atrio-ventricular sequential pacing allows a significant increase in LV stroke volume over single chamber ventricular pacing both at 75 and 120 ppm. Programming the optimal A-V delay is absolutely necessary to obtain this hemodynamic benefit at the higher stimulation rate.

Aged↗