bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of the CO2 laser in soft tissue dental surgery
Authors: Pick Robert M. , Pecaro Bernard C. 
Published: March 2007

AbstractThe use of the carbon dioxide laser for the removal of soft tissue lesions in the oral cavity is presented. The laser was used to remove numerous benign lesions and growths, for incisional and excisional biopsies, and for the removal of microinvasive and macroinvasive carcinomas. Owing to its coagulation properties, the laser was used effectively in treating patients with oral lesions compounded by blood dyscrasias. Because of the advantages of a relatively bloodless surgery; decreased postoperative discomfort; minimal swelling and scarring; and the laser's ability to coagulate, vaporize, or cut, the CO2 surgical laser offers the dental surgeon a viable and in many cases an improved alternative to the scalpel. Laser techniques and several case reports are discussed.
An alternative method of vascular anastomosis by laser: Experimental and clinical study
Authors: Okada Masayoshi , Shimizu Kazuta , Ikuta Hiroshi , Horii Hiroyuki , Nakamura Kazuo 
Published: March 2007

AbstractIn vascular surgery, it is now very difficult to maintain the long‐term patency after a conventional vascular anastomosis, especially for small‐caliber vessels. A low‐energy CO2 laser was experimentally employed to make a vascular anastomosis with only a few sutures. Subsequently, it could be confirmed that optimal conditions for vascular anastomosis by laser were 20–40 mW in output and 6–12 sec/mm in irradiation time. On the other hand, pressure tolerance test as well as tensile strength test and microscopic examinations at the sites of anastomoses by laser were compared with the conventional suture method. There were no significant differences between laser and suture methods. On the basis of the excellent results of this study, the laser was clinically applied for anastomoses of the peripheral vessels in 35 patients. The first clinical laser application in the world was successful in a 44‐year‐old female patient with chronic renal failure in 1985. All patients are doing well without any complications from vascular anastomosis by laser. From these experimental and clinical studies, it can be concluded that anastomosis by laser should be recommended for small‐caliber vessels such as aortocoronary bypass surgery.
Tissue interactions and measurement of ablation rates with ultraviolet and visible lasers in canine and human arteries
Authors: Sartori Michele , Henry Philip D. , Sauerbrey Roland , Tittel Frank K. , Weibaecher Donald , Roberts Robert 
Published: March 2007

AbstractAblation rates measured as the depth of tissue excavation per unit time were determined in human and canine aortas subjected to radiation with ultraviolet (UV) excimer (ArF 193 nm, KrF 248 nm, XeF 351 nm) and visible lasers [continuous wave (cw) and 50‐ms chopped argon ion, 478 nm‐514 nm: pulsed double‐frequency Nd:YAG, 532 nm]. For UV and pulsed double‐frequency Nd:YAG lasers ablation rates were constant in time and depended linearly on average laser power, but for cw and chopped argon lasers ablation rates varied with irradiation time and were nonlinearly dependent on laser power. In human aortas, atherosclerosis without gross calcification had no influence on ablation rates. Charring and tissue disruption were observed with cw and chopped argon ion, whereas excimer and pulsed Nd:YAG lasers produced only minimal injury to surrounding tissue. We conclude that the determination of ablation rates is useful for the selection of laser wavelengths and power densities applicable to angioplasty and that UV and pulsed visible lasers permit a better control of ablation compared to continuous wave lasers.
NADH in situ laser fluorimetry: Effect of pentobarbital on continuously monitored myocardial redox state
Authors: Renault Guy , Muffat‐Joly Martine , Polianski Juliette , Hardy Roger Ian , Boutineau Jean‐Louis , Duvent Jean‐Louis , Pocidalo PhD Jean‐Jacques 
Published: March 2007

AbstractNAHD laser fluorimetry was applied to in situ monitoring of pentobarbital overload effect on myocardial redox state in rats. Experiments were carried out on open‐chest rats anesthetized with pentobarbital. Use of very thin optical probes allowed measurements of NADH fluorescence directly within the myocardial wall. Quantitative analysis of fluorescent and backscattered light signals was made possible on‐line.In 8 animals, a slow IV infusion of 6% pentobarbital (2 mg·min−1 for 10 min) induced an average twofold increase in NADH fluorescence, with constant return to baseline level prior to injection after a maximum period of 50 min. Thus, pentobarbital overload strongly affects the myocardial energetic state, and this effect was precisely evaluated with NADH fluorescence monitoring. In situmonitored myocardial redox state variations during pentobarbital infusion can constitute a reference for similar studies on pharmacological agents aimed at protecting tissues against ischemic biochemical damages.
Smoke from laser surgery: Is there a health hazard?
Authors: Nezhat Camran , Winer Wendy K. , Nezhat Farr , Nezhat Ceana , Forrest Deborah , Reeves William G. 
Published: March 2007

AbstractThe composition of plume produced during carbon dioxide laser endoscopic treatment for endometriosis was examined to determine whether it represented a hazard to the surgical staff. A total of 32 plume samples were collected from 17 women undergoing laser laparoscopic treatment for endometriosis and/or adhesions. The smoke was found to consist of particles having a median aerodynamic diameter of 0.31 μm with a range of 0.10–0.80 μm. The size range has two consequences: (1) using a human red blood cell as a model for all cells, it can be stated with greater than 99.9999% certainty that no cell‐size particles, including cancer cells, are present in the plume; (2) particles in this size range are too small to be effectively filtered by currently available surgical masks.
Sutureless bowel anastomosis using Nd:YAG laser
Authors: Mercer C. D. , Minich P. , Pauli B. 
Published: March 2007

AbstractSmall bowel anastomoses were performed without sutures by using the Nd:YAG laser to produce welded enterotomies. Optimal energy levels for contact and noncontact laser were determined. Anastomoses produced using five target energy levels between 100 and 500 J were examined. Short‐term anastomotic strength of these enterotomies was measured 1 min after the welding. Bursting pressure of the laser welded enterotomies was compared to the bursting pressure of traditional two‐layer, inverting, interrupted sutured bowel anastomoses. The overall mean bursting pressure of non‐contact‐welded enterotomies was 50.6 mmHg. Optimal laser settings determined in this initial phase were then used to produce anastomoses in rabbits which are recovered postoperatively for 1 or 2 weeks in order to examine long‐term viability and integrity of the anastomoses. All chronic rabbit preparations recovered without complication. The mean bursting pressure was 200 mmHg, not significantly different from that of uncut bowel or two‐layer sutured anastomosis.
Phycocyanin: Laser activation, cytotoxic effects, and uptake in human atherosclerotic plaque
Authors: Morcos N. Charle , Berns Michael , Henry Walter L. 
Published: March 2007

AbstractPhycocyanin is a phycobiliprotein with peak absorption at 620 nm. The laser activation, cytotoxic effects, and uptake into atherosclerotic plaque of phycocyanin was studied. Optimal activation was produced by argon dye laser at 0.5 W and a total energy dose of 300 J/cm2 at 620 nm and 650 nm, irradiated through blood with a hematocrit of 8%. Activation was evidenced by reduction of optical density by 0.3 units at 340 nm caused by oxidation of the reduced nicotinamide adenine dinucleotide phosphate (NADPH) in a buffered reaction solution containing 0.1 mg/ml of phycocyanin. Cytotoxicity was evaluated by measuring viability of mouse myeloma cells in culture after incubation with phycocyanin (0.25 mg/ml) and irradiated by 300 J/cm2 at 514 nm. After 72 hours post‐treatment the cells showed 15% viability compared to 69% and 71% for control cells exposed to laser only or phycocyanin only, respectively. Atherosclerotic artery segments obtained within 5 hours postmortem were perfused with 0.1 mg/ml phycocyanin in oxygenated Krebs Ringer solution at 30 mm Hg for 5 minutes followed by washout with phycocyanin‐free Krebs for 10 minutes. Artery sections examined histologically by light and fluorescence microscopy showed specific fluorescence localization within the plaque particularly at the elastic laminae and to a larger extent at the internal elastic lamina but not in the medial muscle layer. In conclusion, phycocyanin is a cytotoxic photosensitizer that exhibits specific binding to plaque and is activated at a wavelength minimally absorbed by blood. These properties suggest potential therapeutic use for plaque localization and regression.
Mechanism of tissue fusion in argon laser‐welded vein‐artery anastomoses
Authors: White Rodney A. , Kopchok George E. , Donayre Carlos E. , Peng Shi‐Kaung , Fujitani Roy M. , White Geoffrey H. , Uitto Jouni 
Published: March 2007

AbstractThe mechanism of laser vascular tissue welding remains unknown. This study compared the acute tissue response and long‐term healing of sutured and laser‐welded anastomoses of vein segments used to bypass ligated canine femoral arteries. For each procedure, one anastomosis was formed using running 6‐0 polypropylene suture (control), and the other anastomosis was formed using argon laser tissue welding (experimental). The vein grafts were harvested at 4 (n = 2), 8 (n = 1), 12 (n = 1), and 16 (n = 2) weeks, and selected samples were evaluated by histologic examination, electron microscopy, tensile strength testing, and by measuring the formation of [3H]hydroxyproline as an index of collagen synthesis. Examination of successful laser fusions immediately after they were formed showed bonding of collagen to collagen and elastin to collagen. Follow‐up evaluations showed that the precision of tissue apposition affected the rate of healing and tensile strength. Laser‐welded anastomoses demonstrated a progression of healing similar to sutured repairs, with remodeling of fibrous tissue and collagen being the primary component of weld integrity. This study demonstrates that sutured and argon laser‐welded vein‐artery anastomoses heal comparably up to 16 weeks postoperatively, and that laser welding is a satisfactory alternative to sutured anastomoses.
Robotized scanning laser handpiece for the treatment of port wine stains and other angiodysplasias
Authors: Rotteleur G. , Mordon S. , Buys B. , Sozanski J. P. , Brunetaud J. M. 
Published: March 2007

AbstractPort wine stains are currently treated by the argon laser with the “point‐by‐point” technique, or the “painting technique.” In both cases, the quality of the results depends greatly on the dermatologist's experience. Furthermore, the first technique is slow, and the second is painful and requires anesthesia. Therefore, we have decided to design a robotized system with the following specifications: easy, fast, nonpainful treatment giving a homogeneous and reproduceable blanching. The system is made of a handpiece with the scanning mechanism and a control box with the microprocessor. The system is independent of the laser (no electrical connection) and has its own power meter. The deposit of energy was optimized in function of heat diffusion in the skin. Over a 12‐month period, 123 patients were treated with the robotized handpiece. The treatment modalities and the results conformed to the above‐mentioned specifications. Hypertrophic scars were not reported. Therefore, we think that this system will be an interesting tool for the laser treatment of port wine stains and other cutaneous angiodysplasias.
Photodynamic therapy: Response of normal canine urethra using a cylindrical fiber
Authors: Manyak Michael J. , Matthews Donna M. , Smith Paul D. , Nochomovitz Lucien E. , Russo Angelo 
Published: March 2007

AbstractNormal urethral response to photodynamic therapy (PDT) utilizing a cylindrical fiber was assessed in ten study and two control NIH foxhounds. The canine urethras were treated 48 hours after intravenous injection of 3 mg/kg dihematoporphyrin ether (Photofrin II). A 1‐mm fused silica optical fiber, with the distal 2–3 cm modified for cylindrical light distribution (660‐μm diameter), was placed in the pendulous urethra. An argon‐pumped dye laser delivered 100 mW of 630‐nm light for 7 minutes (42 J) to the treatment area. Urethroscopy using either a 2.5‐mm or a 2.8‐mm flexible pediatric bronchoscope with video recording capability was performed immediately after PDT (12 animals) and 6 weeks later (nine animals); intravenous urography was performed 3 days and 6 weeks after PDT. There was no evidence of either urethral damage or stricture formation in any animal. Histopathology of the first three study specimens, obtained at 6 weeks, confirmed the absence of any pathology. Flexible instrumentation facilitates post‐treatment assessment. This study demonstrates for the first time that, when a cylindrical fiber is used, photodynamic therapy may be applied to the urethra without damage to the normal urethral mucosa. This result has implications for potential treatment of initial or recurrent carcinoma in situ of the urethra using PDT.
CO2 and argon laser vascular welding: Acute histologic and thermodynamic comparison
Authors: Kopchok George E. , White Rodney A. , White Geoffrey H. , Fujitani Roy , Vlasak Jerry , Dykhovsky Leon , Grundfest Warren S. 
Published: March 2007

AbstractCO2 and argon lasers have been used successfully for vascular welding in both experimental and clinical settings. This study compared the thermodynamics during CO2 and argon laser welding of 1‐cm longitudinal arteriotomies in a canine model. Continuous recordings using an AGA 782 digital thermographic system with spatial and thermal resolution of ±0.2 mm and ±0.2°C, respectively, were analyzed. A HGM argon laser using a 300‐μm optic fiber held at 1 cm from the vessel edges (spot diameter = 2.8 mm) with concomitant room temperature saline irrigation (1 drop/sec) was used for argon welds. Total exposure time was 150 sec/cm. CO2 welds were performed with a Sharplan CO2 laser (spot diameter = 0.22 mm) with no irrigation for total exposure time of 10 sec/cm. Thermodynamic results and laser parameters are summarized as follows: Argon–n = 20; power = 500 mW; energy fluence = 1,400 J/cm2; Tmax = 48.8°C; T mean ± S.D. = 45.1 ± 2.7°C; CO2–n = 20; power = 150 mW; energy fluence = 3,000 J/cm2; Tmax 84.0°C; T mean ± S.D. = 60.7 ± 9.8°C. There was a significant difference (P < .05) in thermal measurements between successful CO2 and argon vascular welds. Temperature rise during the argon welds was limited by saline irrigation. In contrast, during CO2 laser welding, the temperature rose quickly to its maximum and was maintained at a relatively high level as the laser progressed (0.1 cm/sec) along the anastomosis. Histologic examination revealed charring at the CO2 weld site but absence of thermal damage at the argon laser weld. These thermodynamic differences may account for the different welding mechanisms currently described.
The first sutureless, laser‐welded, end‐to‐end bowel anastomosis
Authors: Sauer Jude S. , Hinshaw J. Raymond , McGuire Kevin P. 
Published: March 2007

AbstractThe use of laser energy to weld together tissue offers great promise in the expanding field of laser surgery. The published results of laser welding intestinal tissue have, to date, been limited to the successful laser closures of small enterotomies. This is the first report of using laser energy alone to create an end‐to‐end small bowel anastomosis. A biocompatible, water‐soluble, intraluminal stent was employed during the laser welding of this sutureless, stapleless ileal anastomosis in a rabbit model. Excellent recovery and healing were observed. The rapidity, ease, and potential for full precision automation of laser welding mandates further research.
Fluorescence spectroscopy guidance of laser ablation of atherosclerotic plaque
Authors: Deckelbaum Lawrence I. , Stetz Mark L. , O'Brien Ken M. , Cutruzzola Francis W. , Gmitro Arthur F. , Laifer Lawrence I. , Gindi Gene R. 
Published: March 2007

AbstractLaser‐induced fluorescence (LIF) spectroscopy can only be used for laser angioplasty guidance if high‐power laser ablation does not significantly alter the pattern of tissue fluorescence. Although the spectra of normal and atherosclerotic arteries differ, the change in fluorescence spectra following laser angioplasty has not been well studied. Therefore, the purpose of this study was to assess whether laser‐induced fluorescence spectroscopy could guide selective laser ablation of atherosclerotic plaque and, if so, to develop a quantitative LIF score that could be used to control a “smart” laser angioplasty system.Baseline LIF spectroscopy of 50 normal and 50 atherosclerotic human aortic specimens was performed using an optical fiber coupled to a He‐Cd laser and optical multichannel analyzer. LIF was then serially recorded during erbium:YAG laser ablation of 27 atherosclerotic specimens. Laser ablation was terminated when the arterial LIF spectrum visually appeared normal. Histologic analysis revealed a mean initial plaque thickness of 1,228 ± 54 μm and mean residual plaque thickness of 198 ± 27 μm. Ablation of the media occurred in only three specimens.A discriminant function was derived to discriminate atherosclerotic from normal tissue for computer guidance of laser angioplasty. The LIF score, derived from stepwise multivariate linear regression analysis of the LIF spectra, correctly classified 93% of aortic specimens. The spectra obtained from the atherosclerotic specimens subjected to fluorescence‐guided laser revealed a change in score from “atherosclerotic” to “normal” following plaque ablation. Seven atherosclerotic specimens were subjected to laser angioplasty with on‐line computer control using the LIF score. Mean initial plaque thickness was 1,014 ± 86 μm, and mean residual plaque thickness was 78 ± 29 μm. There was no evidence of ablation of the media. Therefore, LIF guidance of laser ablation resulted in minimal residual plaque without arterial perforation. These findings support the feasibility of an LIF‐guided laser angioplasty system for selective atherosclerotic plaque ablation.
Photofrin II localization in rat cecum
Authors: Bjorkman David J. , Brigham Earl J. , Peterson Brian J. , Straight Richard C. 
Published: March 2007

AbstractLaser excitation of photodynamic agents localizing in colonic tumors may allow the early diagnosis and treatment of colon cancer. The efficacy of these agents requires a high ratio of tumor to background photosensitizer accumulation and fluorescence. To assess normal colonic background fluorescence and hematoporphyrin accumulation 31 rats were studied after an intravenous injection of Photofrin II (PF‐II) at a dose of 5 mg/kg. An increase in mucosal fluorescence and porphyrin content was noted in the cecum 24 hours after injection.Cecal accumulation of PF‐II may affect its efficacy in the localization and treatment of cecal tumors. Further investigation into the mechanism and clinical significance of this finding is needed.
Spectroscopic differences between human cancer and normal lung and breast tissues
Authors: Tang G. C. , Pradhan A. , Alfano R. R. 
Published: March 2007

AbstractSteady‐state spectra, time‐resolved spectroscopic, and excitation spectra from human cancer and normal tissues have been measured. Spectroscopic differences between normal and cancerous tissues have been found that could be used as a basis for an instrument for the early detection of cancer.
Er:YAG laser ablation of tissue: Effect of pulse duration and tissue type on thermal damage
Authors: Walsh Joseph T. , Flotte Thomas J. , Deutsch Thomas F. 
Published: March 2007

AbstractThe thermal damage caused by 2.94‐μm Er:YAG laser ablation of skin, cornea, aorta, and bone was quantified. The zone of residual thermal damage produced by normal‐spiking‐mode pulses (pulse duration ≈ 200 μs) and Q‐switched pulses (pulse duration ≈ 90 ns) was compared. Normal‐spiking‐mode pulses typically leave 10–50 μm of collagen damage at the smooth wall of the incisions; however, at the highest fluences (≈ 80 J/cm2) tears were produced in cornea and aorta and as much as 100 μm of damaged collagen is found at the incision edge. Q‐switched pulses caused less thermal damage, typically 5–10 μm of damage in all tissues.
Er:YAG laser ablation of tissue: Measurement of ablation rates
Authors: Walsh Joseph T. , Deutsch Thomas F. 
Published: March 2007

AbstractThe ablation of both soft and hard tissue using the normal‐spiking‐mode Er:YAG laser has been quantified by measuring the number of pulses needed to perforate a measured thickness of tissue. Bone is readily ablated by 2.94 μm radiation; however, at per pulse fluences greater than 20 J/cm2, plasma formation decreases ablation efficiency. At low fluence, desiccation can prevent efficient ablation of bone. The ablation efficiency for aorta and skin is higher than for bone. The ablation efficiency, 540 μg/J, and the ablation depth per pulse, >400 μm, for skin are too high to be readily explained by simple models of ablation and thus provide evidence for a more complex explosive removal process.
Laser dentistry: A new application of excimer laser in root canal therapy
Authors: Pini Roberto , Salimbeni Renzo , Vannini Matteo , Barone Roberto , Clauser Carlo 
Published: March 2007

AbstractWe report the first study of the application of excimer lasers in dentistry for the treatment of dental root canals. High‐energy ultraviolet (UV) radiation emitted by an XeCl excimer laser (308 nm) and delivered through suitable optical fibers can be used to remove residual organic tissue from the canals. To this aim, UV ablation thresholds of dental tissues have been measured, showing a preferential etching of infiltrated dentin in respect to healthy dentin, at laser fluences of 0.5–1.5 J/cm2. This technique has been tested on extracted tooth samples, simulating a clinical procedure. Fibers of decreasing core diameters have been used to treat different sections of the root canal down to its apical portion, resulting in an effective, easy, and fast cleaning action. Possible advantages of excimer laser clinical applications in respect to usual procedures are also discussed.
Ocular fluorometry: Principles, fluorophores, instrumentation, and clinical applications
Authors: Docchio Franco 
Published: March 2007

AbstractOcular fluorometry is rapidly evolving as a versatile technique for research and diagnosis in ophthalmology. The main reasons for this increasing success are (1) the ideal characteristics of the eye as an optical device for excitation of tissue fluorescence and for the detection of the fluorescent emission; (2) the development of novel fluorometric techniques, including differential and time‐resolved fluorescence spectroscopy; and (3) the increasing use of coupling geometries with high‐resolution and high spatial selectivity. Both endogenous and exogenous fluorophores are of interest to ocular fluorometry. The most significant among endogenous fluorophores are the fluorescing pigments of the lens and of the retinal pigment epithelium (RPE). The nature, topography, and fluorescence properties of such pigments depend on age and pathology and on the level of light exposure. Exogenous fluorophores of interest are both intentionally induced and unintentionally accumulated drugs (some of which are phototoxic). Laser‐based fluorometric techniques play a leading role in ocular fluorometry. The peculiar properties of the laser for the excitation of fluorescence make this source a favorite candidate for ocular fluorometry both in vitro and in vivo.