Biomedical subjects

Marcos Pinotti

Publications and source records attributed to Marcos Pinotti.

4 recordsLinked to original sources

PubMed2006

Clinical study of the gingiva healing after gingivectomy and low-level laser therapy.

OBJECTIVE: The purpose of this study was to investigate gingival healing after gingivectomy and adjunctive use of low-level laser therapy (LLLT). BACKGROUND DATA: LLLT has been used in animal experiments to examine the influence of laser radiation on the wound healing process since the 1960s. However, clinical trials in dentistry are scarce, and most of them refer to treatment after extraction of the third molars, with only a few reports in the area of periodontics. METHODS: Twenty patients with periodontal disease were selected, and treatment was planned for gingivectomy to bilateral maxillary and mandibular premolar teeth. After surgery, one side was submitted to LLLT using a 685-nm wavelength, output power of 50 mW, and energy density of 4 J/cm(2). The other side was used as the control and did not receive laser irradiation. Healing was evaluated, clinically and biometrically, immediately post-surgery and at days 3, 7, 14, 21, 28, and 35. Results were submitted to statistical analysis. RESULTS: Biometrical evaluation indicated a significant improvement in healing for the laser group at 21 and 28 days. Clinical evaluation showed better repair for the laser group, mainly after the third day. CONCLUSION: LLLT was an effective adjunctive treatment that appeared to promote healing following gingivectomy.

Gingiva↗

PubMed2004

Particle image velocimetry for flow analysis in longitudinal planes across a mechanical artificial heart valve.

In the last decades a great number of in vitro studies have been conducted to improve the design and to understand the transvalvular flow patterns under steady-state and pulsating flow conditions. Steady-state tests are useful for studying the flow established upstream and downstream of the valve prosthesis in different flow conditions and, in particular, at the peak flow rate. In the present study, the particle image velocimetry (PIV) technique is employed to visualize the flow patterns in a precommercial model of a bi-leaflet mechanical heart valve prosthesis in a steady-state flow regime. The use of the PIV technique and a convenient test rig provide good conditions with which to investigate the whole flow field upstream and downstream of the valve. Velocity and vorticity maps are obtained for the flow passing through the prosthesis in different axial planes. A new and simple solution for the measurement test chamber is proposed. This innovative approach of observing the flow in staggered planes (other than diametrical planes) allows a flow analysis to be performed upstream and downstream of the valve in regions near the tube wall where it has the maximum potential for injury of the vessel's inner cell layer.

Blood Flow Velocity↗

PubMed2003

Improvement on the auxiliary total artificial heart (ATAH) left chamber design.

The auxiliary total artificial heart (ATAH) is an electromechanically driven artificial heart with reduced dimensions, which is able to be implanted in the right thoracic or abdominal cavities of an average human patient without removing the natural heart or the heart neurohumoral inherent control mechanism for the arterial pressure. This device uses a brushless direct current motor and a mechanical actuator (roller screw) to move two diaphragms. The ATAH's beating frequency is regulated through the change of the left preload, based on Frank-Starling's law, assisting the native heart in obtaining adequate blood flow. The ATAH left and right stroke volumes are 38 ml and 34 ml, respectively, giving approximately 5 L/min of cardiac output at 160 bpm. Flow visualization studies were performed in critical areas on the ATAH left chamber. A closed circuit loop was used with water and glycerin (37%) at 25 degrees C. Amberlite particles (80 mesh) were illuminated by a 1 mm planar helium-neon laser light. With left mean preload fixed at 10 mm Hg and the afterload at 100 mm Hg, the heart rate varied from 60 to 200 bpm. Two porcine valves were used on the inlet and outlet ports. The flow pattern images were obtained using a color micro-camera and a video recorder. Subsequently, these images were digitized using a PC computer. A persistent stagnant flow was detected in the left chamber inlet port. After improvement on the left chamber design, this stagnant flow disappeared.

Animals↗

PubMed2003

Modeling and simulation of pulsatile blood flow with a physiologic wave pattern.

This article presents a computational fluid dynamics (CFD) model to analyze pulsatile blood flow in a human artery. The model assumes the vessel as being a straight wall tube, and the blood flow is considered to be incompressible, Newtonian, and axisymmetric. Physiologically realistic resting conditions were adopted for the simulation tests. The main objective was to identify regions where pulsatile effects were significant. Velocity profiles were obtained for both normal and stenosed vessels. The results have shown that, for normal vessels, pulsatile effects prevail close to the vessel wall. The presence of stenosed sections resulted in flow alterations, with flow recirculation areas changing both size and location during the cardiac cycle. These results are especially important in the design of artificial organs. The knowledge of the flow pattern in complex geometries such as artificial hearts, prosthetic valves, and ventricular assist devices can help avoid or minimize thrombogenesis and hemolysis.

Arteries↗