Biomedical subjects
Publications and source records attributed to L Martini.
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In order to study the interaction between the laser and biological tissues, we realized an experimental "in vivo" model using 12 Wistar male adult rats (mean b.w. 300 gr.). On the animals, during general anesthesia and after an accurate shearing of the back, we performed a cutaneous lozenge in order to value the characteristics and the possibilities of a last generation laser. It concerns of a CO2 laser (EASY LASER SP5, CLASS IV F.D.A.) with the possibility of employing of different variables. During this study were evaluated the most interesting variables: frequency, power and duty cycle. Among the variables we identified the frequency of the application range of the superpulse effect and the selective photothermolysis. The histological and morphological studies performed on the cutaneous specimens after laser treatment, showed that the correct application of this kind of laser can be an effective help for the surgeon during clinical practice.
The interest in developing a prosthesis that may be effective in nerve repair as an alternative to autologous grafts, promotes experimental investigations in order to improve the so called tubulization techniques. A review of the literature of the last 10 years is performed to draw an outline of the state of the research, pointing out three main topics: the animal model, the type of the conduit and the length of the repaired gap. The rat, the rabbit and non human primates are the species with which experimental models are most often fashioned for this purpose. Among the great number of investigated conduits, interesting perspectives are arrived at mainly by those obtained with biologic or degradable materials; until now, experimental nerve defects of 3 cm or less are better repaired with artificial guides while unsatisfactory results were reported for the repair of longer gaps. The introduction in the micro-environment of the conduit of neurotrophic substances represents a challenge for the future development of these investigations aimed at improving healing and obtaining nerve regeneration through extensive defects.
Within an experimental study project about the interaction between Laser and biological tissues, the authors utilized a Laser Doppler Flowmeter device and a Polarographic method to study the cutaneous microcirculation and the tissue pO2. Under standardized conditions, the experimental model considered the microcirculation measurement and the ptiO2 before and after the exsection of a cutaneous lozenge on the animals back realized with traditional surgical methods (scalpel and electrotome) or with a last generation CO2 Laser in continuous and in pulsed mode. The Laser Doppler Flowmeter showed that the largest perturbation of the microcirculatory flux occurred after the exsection realized with the scalpel and the electrotome. The CO2 Laser utilized in continuous mode showed an influence slightly lower on the microcirculation while in pulsed mode the perturbation was absent. The ptiO2 measurement showed similar results emphasizing that the CO2 surgical Laser technique is less invasive than the traditional. To sum up, these functional methods allowed a careful microcirculation an ptiO2 evaluation and provided useful information about vasal and metabolic alterations, showing that the CO2 surgical Laser utilized in pulsed mode appears to be the less harmful surgical technique for the tissues surrounding the exsection site.
L-arginine and L-lysine are essential amino acids which seem to possess some properties able to influence bone fractures healing. In fact, they seem to be involved not only in the increase of intestinal calcium adsorption but also in collagen synthesis, in insulin and growth hormone secretion and in osteoblastic activation. So, an experimental in vivo model was carried out by using 50 adult rabbits which, under general anaesthesia, were submitted to an osteotomy of the left fibula. Animals were divided into 5 groups and were daily treated with a mixture of lactose, L-arginine and L-lysine or with the only lactose (control group) at the same dosage as recommended for humans. They were sacrificed after 15, 30, 40, 50 and 60 days for radiological and histological studies. The results of the study showed that the pharmacological mixture containing L-arginine and L-lysine accelerates and ameliorates the healing processes and this positive effect was particularly evident from the 30th day after the osteotomy. We think that these results are linked not only to calcium metabolism but also to different biological properties which positively contribute to a good healing of bone fractures.
Biodegradable polymers gives interesting perspectives of use in making artificial conduits for peripheral nerve reconstruction. Poliphosphazenes are materials highly biocompatible and have a controllable reabsorption rate. According to the substitutes that are introduced in the molecule, they can also be used as a framework for drug release. Conduits obtained with poli [bis(etilalanate) phosphazene] were evaluated as guides for nerve regeneration in an experimental animal model. In six Wistar rats, under general anesthesia and with microsurgical technique, the ischiatic nerve was isolated. On the right side a segment of the nerve was removed in order to create a 10 mm gap. The defect was then repaired using the conduit. On the controlateral limb the nerve continuity was restored using as an autograft the segment removed from the right. Control were performed at 30, 90, 180 days and consisted in histological and electron microscopy investigations. They showed the gradual degradation of the conduit without signs of local and general toxicity. The regeneration of the nerve fibers in the lumen of the conduit was not significantly different from the one obtained with the autologous grafts. So poliphosphazene conduits may be considered effective as a guide for nerve regeneration, above all for the possibility of use the polymer as a carrier for neurite-promoting factors.