Jorge Humberto Nicola

Mechanisms of polymer film deposition from r.f. discharges of acetylene, nitrogen and helium mixtures☆

Mixtures of C2H2, He and N2 were polymerized in an r.f. discharge. Quantitative optical emission spectroscopy was used to determine relative concentrations of the key species CH and CN in the plasma as a function of the proportions of monomer gases in the feed, and to delineate the behavior of the electron mean energy and number density in the discharge. Transmission IR spectroscopy (IRS) and electron spectroscopy for chemical analysis (ESCA) of films deposited from discharges containing different proportions of nitrogen revealed the incorporation of both CH and CN in the deposited material. Deposition rates were also determined and their connection with deposition mechanisms via gas-phase and surface reactions is outlined.

Criptolise por coagulação com laser de CO2 em tonsilite crônica caseosa: método conservador e resultados

Introduction: Conventional cryptolysis with CO2 laser has been performed with success and in this case, a considerable volume of tissue is removed without warring about possible reduction of the immunological function of the tonsils. In the present paper we propose an alternative cryptolysis method with CO2 laser for chronic causeous tonsillitis. In this way, the desired effect is obtained by coagulation with laser and not by the volatilization of the tissues. The preservation of tissues is optimized. Method of study: Clinical prospective. Objectives: To present a modified cryptolysis technique with CO2 laser, which inhibits the retention of the caseous and preserves the tonsilar parenchyma. Material and Method: The cryptolysis were performed on a group of thirty-one individuals with chronic causeous tonsillitis, with great elimination of caseous and other associated symptoms. The patients were selected from the ORL HC-UNICAMP ambulatory. We used 6W CO2 laser in continuous mode, unfocused, and Swiftlase around the opening of the crypts, and, afterwards over the entire tonsilar surface producing only a superficial coagulation. To eradicate the symptoms we performed on average seven applications, repeated every three weeks. Results: The proposed technique was effective in 87% of the cases. For the remaining 13%, it was also necessary to volatize the regions adjacent to the crypts. There was a two-year follow-up without evidence of complications. Conclusion: We conclude this to be a safe and efficient method, able to be performed in the ambulatory under topic anesthesia; therefore, permitting to the patients immediate return to their activities.

Histopathological evaluation in biopsies of palatine tonsils submitted to cryptolysis by coagulation with CO2 laser for treatment of chronic caseous tonsillitis.

OBJECTIVE To perform histopathological evaluation in biopsies of palatine tonsils in a group of patients, with symptoms of chronic caseous tonsillitis, treated with an innovative and conservative method, using CO(2) laser. BACKGROUND DATA In general, the treatment of chronic caseous tonsillitis with CO(2) laser, as described in the literature, refers to the clinical experience of the authors and, the technique used for criptolysis encourages tissue vaporization, which leads to the consequent reduction of the tonsillar parenchyma. MATERIALS AND METHODS The individuals were submitted to cryptolysis coagulation with only 6 W of CW, CO(2) laser power, in scanned and unfocused mode, over a mean area of 2.2 mm diameter, leading to energy doses from 18 to 54.5 joules/cm(2). Biopsies were performed at the beginning and end of each treatment. A comparative analysis was performed between the initial and final biopsies taking into consideration possible alterations in the following: germinal centers, lymphoid tissue, sub-epithelial fibrosis, and parenchyma fibrosis. RESULTS The histopathological analysis of these biopsies showed that the laser, used at a specific energy density, could relieve the symptoms of the disease causing neither increase of the fibrotic content nor decrease of the lymphoid structure. The action of the laser, following the proposed technique, is superficial, causing only epithelial coagulation, which enables a weakening of the tension forces in the crypt borders, causing them to open. This effect results in the reduction and even disappearance of caseous retention. CONCLUSION We, therefore, conclude that the proposed method of treatment with CO(2) laser, called laser cryptolysis by coagulation (LCC) is an effective and conservative method, causing no significant morphological alterations to the tonsils.

Wavelength, frequency, and color: absolute or relative concepts?

OBJECTIVE The purpose of the present study is to call attention to well-established concepts in optics, which, however, are not necessarily known by medical laser users but may be important for interpretation of some data. BACKGROUND DATA In reviewing some aspects of the physical concepts of wavelength, frequency, photon energy, and color, it was possible to establish, beyond doubt, the right conditions to use these terms to classify specific laser radiations. This may help in the correct interpretation of some low-level laser therapy (LLLT) experimental results. MATERIALS AND METHODS In order to achieve our objective--maintaining the readers interest--we use the simplest physical concepts and equations necessary for nonphysicists to understand this subject. RESULTS The most important result pointed out through this study is the fact that the numerical value for wavelength, normally assigned to commercial lasers, should not be used to describe the light propagation inside the tissue. CONCLUSION The knowledge of the relation among the magnitudes discussed in the present study and their effects, although it does not add much to the use of a laser merely as a cutting instrument, becomes of fundamental significance when used to determine the effects that depend on light propagation within biological tissue and that do not result only from absorption of light energy. This will certainly help in the understanding of phenomena whose causes are attributed to the electric and magnetic polarization of laser radiation, as seems to be the case observed in laser biostimulation.

Photodynamic effect produced by HeNe radiation in Harderian glands of Wistar rats: an experimental model for PDT studies

In rats, the Harderian Gland secret Protoporphirin IX which is retained at acinar lumina. Since this photosensitizer is important for PDT of malignant tumors, we propose to study this gland as a model to help understanding PDT with endogenous photosensitizers. Twenty Wistar SPF adult rats were submitted to surgical exposure of both Harderian glands, revealing red fluorescence upon UV, characterizing the protoporphirin IX presence. After that, one gland of each pair (one kept as control) was irradiated with an 8 mW HeNe (6328 angstrom) for 45 minutes, delivering about 2.7 joules/mm2. After 24 hours a group of 10 animals were scarified and the glands removed for histological analysis. The remaining animals were subjected to the same procedure but the glands were removed immediately after laser treatment. Histological and fluorescence analysis immediately after laser irradiation showed cell fragmentation with loss of acinar architecture with diffusion of protoporphirin in the cytoplasm of damaged cells, as well as interstitial edema. After 24 hours these alterations were more pronounced with accentuated loss of intraluminal protoporphirin and beginning of leukocytic demarcation of necrotic areas. The innate Harderian glands of rats, exposed to HeNe laser, showed a similar behavior as tumor tissue under PDT.

Low-power CO2 laser in the treatment of chronic pharyngitis: a five-year experience

Spatial and temporal coherence are properties of laser light we studied for some time as responsible for biophysical phenomena, capable of significant contributions in the treatment of chronic inflammatory lesions. In this paper we present the results of five years experience in the application of CO2 low power laser (LPL) therapy as a new means of treating chronic pharyngitis. Based on our previous studies, we selected 85 patients with nonspecific chronic pharyngitis to be treated at our laser unit. The patients were grouped as follows: Group I, 40 patients, predominance of hyperemic aspect; and Group II, 45 patients, predominance of hypertrophied aspect. Both groups were submitted to low power irradiation of CO2 laser in eight to ten sessions, one week interval according to the evolution of symptoms. The good results obtained lead us to conclude that this new application for LPL is very suitable for systematic treatment of chronic pharyngitis: a very common and disturbing symptom for a great number of ear, nose, and throat patients, still lacking an effective form of therapy.

Comparative histologic study of alterations in rat skeletal muscles due to carbon dioxide laser with varying power but constant energy

The aim of our study was to compare biolgic effects such as tissue damage and regeneration in rat skeletal muscle after CO2 laser application with pulses of constant energy density, but with varying power and exposure time. We used three different laser conditions: 20 W by 0.5 s, 10 W by 1.0 s and 5.0 W by 2.0 s, all having the same energy density (10 joules in a constant area). The animals were sacrificed immediately after laser application, and after 1, 4, 7, 15 and 21 days. Tissue damage produced by the CO2 laser with high power provokes more profound craters with less tissue damage at the margins. As shown by lesser tissue carbonization, fewer foreign body giant cell granulomas and less tissue fibrosis and, on the other hand, an accelerated regeneration of muscle tissue.

Construction and evaluation of a non-laser optical system for photodynamic process excitation

Purpose: To show that a non-laser light source can be constructed, using a 500 W Tungsten lamp and optical filters, and that this light source produces photodynamic effect via protoporphyrin IX (PpIX) similar to the effect produced by HeNe laser light. Methods: The broad band spectrum from a Tungsten lamp was filtered. Infrared and blue part of the spectrum was discarded by absorption process and the fraction of the spectrum, centered at the red portion, was filtered by an interference filter. Photodynamic effect was studied by the activity on endogenous PpIX of Harderian glands of Wistar rats. Twenty rats were used for the experiment. Each animal had its two Harderian gland surgically exposed, so one of them was treated with the system while the other was kept as control. After a 30 minutes period of treatment, the animals were sacrificed and their glands were removed for histological analysis. This analysis was compared to earlier published results obtained with HeNe laser light. Results: The resultant light source emission was centered around (636 ± 6.5) nm and gives up to 11.3 mW/cm2 power density. It produces photodynamic effect in Harderian gland, observed either by fluorescence spectroscopy or by histological microscopy. Conclusion: There is no noticeable difference in Photodynamic effect results if activated by HeNe laser or by the proposed non-laser light source emitting at the red portion of the spectrum.

Symptomatic Hemangioma of Oral Cavity Treated With CO2 Laser

The CO2 laser has been used by our group as a secure and efficient tool for the treatment of symptomatic oral cavity hemangiomas which can be responsible for disturbance for swallowing, phonation and in hygienic, besides discomfort and bleeding to patients. During the last four years, twelve patients with symptomatic oral cavity hemangioma were treated at the Laser Unit of our University. The treatment consisted in the application of CO2 laser at medium to low intensity according to characteristics and location of the lesions. For hemangiomas located at sites of easy surgical access such as anterior 1/3 of the tongue, lips, bucal vestibule we use 10 to 37 J/mm2 over the surface of the lesion. When the hemangioma was located at difficult surgical access sites, such as, tonsils, posterior 1/3 of tongue, or at pharyngeal wall we used 3.0 to 4.0 J/mm2 encircling the whole hemangioma. This causes reduction in the size of the lesion throughout sclerosis of nutrition vessels. After this initial procedure we applied 0.8 to 1.0 J/mm2 over the whole extent of the lesion. For both procedures we observed no significant bleeding or inflammatory reaction. The patients referred minimal post-operative discomfort with good cicatricial evolution. The evident reduction in the vascularization and size could be confirmed by photographic documentation. The good results described above, with disappearance of symptoms lead to the conclusion that CO2 laser is an efficient and secure method of treatment for symptomatic hemangioma of the oral cavity.

Monitoring of Native Fluorescence Induced by a Glucose Diet in Wistar Rats

OBJECTIVE To investigate red fluorescence found in the digestive tract of Wistar rats submitted to stress produced by a liquid diet of 5% glucose and maintenance in darkness. BACKGROUND DATA Protoporphyrin IX (PpIX) is produced by the Harderian gland, located in the inner corner of the eyes of rats. Under stressful conditions this gland increases the production of PpIX, which can be detected in different regions of the body, in a manner reminiscent of a porphyria. MATERIAL AND METHODS Sixty-five Wistar rats were used in this study. The fluorescence spectra were registered with optical resolution better than 1.7 nm. The rats were fed a 5% glucose diet, exclusively, up to 120 h. The animals were evaluated throughout the diet period, which included two sequential experiments: considering the red fluorescence of their intestinal tract and the fluorescence that appeared in some external parts of their bodies (paw, tail, nose, and scrotum). The normal diet was reintroduced and new spectra were obtained after 24 and 48 h. RESULTS Experiment I showed a marked, time-dependent increase in the intestinal content of porphyrin in rats fed the glucose diet. The fluorescence spectrum of the material identified it as PpIX. The spectra collected in Experiment II showed an increase in fluorescence in the four external areas associated with the duration of the diet. This fluorescence disappeared after reintroduction of the regular diet. CONCLUSION The feeding of a restricted diet (5% glucose) to Wistar rats resulted in reversible porphyria. Measurement of the fluorescence intensity may be a reliable method for monitoring the porphyrin content of tissues.