bluuebunny/crossref_metadata_2025_split huggingface dataset:
Low‐energy CO2 laser intestinal anastomosis: An experimental study
Authors: Rochkind Semion , Rabau Micha Y. , Goldman Gideon , Bar‐Nea Lilian , Wiznitzer Theodor 
Published: March 2007

AbstractIntestinal anastomosis was performed in 17 Wistar rats via tissue welding by the low‐energy CO2 laser.The postoperative course in the animals studied was uneventful. The integrity of the anastomosis was investigated manometrically, immediately upon completion of the anastomosis as well as 20 days later. Ten additional Wistar rats served as controls in which conventional interrupted one‐layer anastomosis was performed. The results show a significant superiority of the intestinal anastomoses that were constructed by means of laser tissue welding. The time to complete the anastomosis was also significantly shorter when laser rather than manual suturing was used.Serial histological examinations for up to 90 days following surgery revealed complete healing and epithelization of the anastomotic site.
Effect of CO2 and blood media on laser probe temperature
Authors: Silverman Steven H. , Khoury Adib I. , Seeger James M. , Tomaru Takanoubu , Hawkins Irvin F. , Abela George S. 
Published: March 2007

AbstractBlood may limit laser ablation of arterial plaque by decreasing thermal energy transfer from metal‐capped probes to arterial occlusions. Since a gas is a good insulator of heat, CO2 may be a better medium for laser recanalization. To study this possibility, a metal‐capped fiber was positioned in a segment of blood‐filled polyethylene tubing and activated with an argon laser. Probe temperatures were measured in blood and as the blood was displaced by flowing CO2 gas. Probe temperatures were higher at all powers studied in CO2 gas than in blood. Maximum probe temperatures averaged 518 ± 24°C after CO2 infusion versus 320 ± 7°C in blood, (P < 0.0001). Blood aggregate formation was noted on the probe surface in blood but not in CO2 medium. Thus CO2 gas may be a preferable medium for laser recanalization, since higher probe temperatures are achieved, and the probe surface remains free of insulating blood coagulate.
In vitro optical properties of human and canine brain and urinary bladder tissues at 633 nm
Authors: Splinter Robert , Cheong Wai Fung , van Gemert Martin J. C. , Welch A. J. 
Published: March 2007

AbstractAbsorption and scattering coefficients and scattering anisotropy factor are presented for human and canine cadaver tissues at the helium‐neon wavelength (633 nm). Measurements were performed with an integrating sphere arrangement and analyzed with the diffusion approximation of the equation of radiative transfer adapted to Kubelka‐Munk techniques.
Dynamic aspects of rhodamine dye photosensitization in vitro with an argon‐ion Laser
Authors: Shea Christopher R. , Chen Norah , Hasan Tayyaba 
Published: March 2007

AbstractPhototoxicity in cultured human bladder carcinoma cells treated by 514.5‐nm argon‐ion laser irradiation plus rhodamine‐123 (R123) or tetrabromo‐R123 (TBR) was assessed by counting total cell number and percent viability at 1, 24, 48, 72, and 96 h after irradiation. TBR was markedly more efficient than R123 at causing both reversible and persistent phototoxic cytostasis. Furthermore, TBR photosensitization caused net cytocidal effects at 0.5 J/cm2, which were not seen with R123 photosensitization at up to 40 J/cm2. The reduced phototoxic efficiency of R123 as compared to TBR appears, in part, to reflect the presence of a fraction of cells refractory to R123 photosensitization.
In vitro photosensitization II. An electron microscopy study of cellular destruction with mono‐L‐aspartyl chlorin e6and photofrin II
Authors: Roberts W. Gregory , Liaw L.‐H. L. , Berns Michael W. 
Published: March 2007

AbstractPrimary sites of subcellular destruction with photofrin II (PfII) and mono‐L‐aspartyl chlorin e6(MACE) were determined by transmission electron microscopy (TEM).Potorous tridactylus(PTK2) cells were grown in Rose chambers and incubated for 24 hr with a sensitizer concentration sufficient to provide 100% mortality. Cells were irradiated with laser light and fixed and processed for electron microscopy at various times post‐irradiation. The results indicate that PfII initially destroys mitochondria, whereas MACE destroys lysosomes. Both conclusions are consistent with fluorescence subcellular localization studies.
Change in laser‐induced arterial fluorescence during ablation of atherosclerotic plaque
Authors: Cutruzzola Francis W. , Stetz Mark L. , O'Brien Kenneth M. , Gindi Gene R. , Laifer Lawrence I. , Garrand Timothy J. , Deckelbaum Lawrence I. 
Published: March 2007

AbstractAnalysis of the change in arterial fluorescence during plaque ablation may provide the basis for developing a fluorescence guided ablation system capable of selective plaque ablation without risk of vessel perforation. Accordingly, fluorescence spectra were recorded from 91 normal and 91 atherosclerotic specimens of cadaveric human aorta. The ratio of the laser‐induced fluorescence intensity at 382 nm to 430 nm (LIF ratio) was capable of classifying these specimens with an 89% accuracy with a threshold value of 1.8 (atherosclerotic ⩾1.8, normal <1.8). To characterize the change in fluorescence during plaque ablation, mechanical plaque ablation with a cold microtome was performed on 16 atherosclerotic aortic specimens. Fluorescence spectra were recorded serially after each 100 μm of plaque ablation; recordings revealed a change in fluorescence spectra from atherosclerotic to a normal pattern. With an LIF ratio of 1.8 to signal termination of plaque ablation, 15 of the atherosclerotic plaques had a residual plaque thickness less than 200 μm; one specimen had a residual plaque thickness of 300 μm. No specimen demonstrated ablation of the media. There was a statistically significant correlation between LIF ratio and plaque thickness (r = .73, P < .001), but considerable variation in LIF ratio existed at each thickness. Therefore, laser‐induced fluorescence spectroscopy is capable of discriminating atherosclerotic from normal aorta and of signaling completion of plaque ablation.
Excimer ablation of human intervertebral disc at 308 nanometers
Authors: Wolgin Mark , Finkenberg John , Papaioannou Thanassis , Segil Clive , Soma Charles , Grundfest Warren 
Published: March 2007

AbstractExcimer laser energy, which has been shown to photoablate tissue at a precisely controllable rate with minimal thermal damage, was applied to human intervertebral disc in an effort to develop a technique for percutaneous discectomy. Cadaveric samples of human disc were used. Excimer laser energy was produced by a XeCl, magnetically switched, long‐pulse laser working at 308 nm, 20 Hz. Annulus tissue of approximately 1 mm thickness was placed in contact with the output tip of a 400 μm core diameter quartz fiber, and measurements of ablation rate were made at different radiant exposures. Ablation rates were found to vary linearly with radiant exposure, from 0.7 μm/pulse at 10 mJ/mm2 to 11.0 μm/pulse at 55 mJ/mm2, with a correlation coefficient of 0.984. Threshold radiant exposure, calculated by extrapolation, was found to be about 7 mJ/mm2. Histologic analysis showed a minimum of thermal damage in these specimens, and when ablated with modification to maintain constant fiber‐tissue contact, thermal injury was nearly absent, as compared to samples ablated with Nd:YAG through a contact probe. Thermographic analysis, performed using the AGA 782 Digital Thermography system, showed increasing temperature with increasing radiant exposure, with a maximum temperature of 47.2°C at 55 mJ/mm2. In that precise tissue ablation was demonstrated with minimal generated heat, and excimer energy at 308 nm is transmissible through fiber optics, excimer holds great promise for the development of a percutaneous discectomy technique.
Ablation of bone and polymethylmethacrylate by an XeCl (308 nm) excimer laser
Authors: Yow Lindy , Nelson J. Stuart , Berns Michael W. 
Published: March 2007

AbstractOne of the main problems in orthopaedics is the surgical removal of hard substances, such as bone and polymethylmethacrylate (PMMA). Such materials are often very difficult to remove without mechanical trauma to the remaining tissue. This study investigated the feasibility of the ultraviolet 308 nm excimer laser in the ablation of these materials. The beam was delivered through a 1 mm‐diameter fiber optic at 40 Hz with energy densities at the target surface of 20–80 J/cm2 per pulse.The goal of the study was to establish the ideal dosimetry for removing bone and PMMA with minimum trauma to the adjacent tissue. Histology revealed that the 308 nm laser effectively removed bone leaving a thermal damage zone of only 2–3 μm in the remaining tissue. Increasing the energy per pulse gave correspondingly larger and deeper cuts with increasing zones of thermal damage. The excimer laser was also effective in the ablation of PMMA, creating craters in the substrate with a thermal damage zone of 10–40 μm. The debris from both substrates was evaluated.
Parameters affecting laser palliation in patients with advanced digestive cancers
Authors: Brunetaud Jean Marc , Maunoury Vincent , Cochelard Dominique , Boniface Brigitte , Cortot Antoine , Paris Jean Claude 
Published: March 2007

AbstractNinety‐nine nonsurgical patients (group I) with esophagogastric cancer were referred to the laser center for palliation of dysphagia, and another 142 nonsurgical patients (group II) with a rectosigmoid cancer were referred for palliation of abnormal rectal discharge (125 patients) or occlusion (17 patients). The immediate success rate was 83% in group I and 90% in group II. Patients were retreated monthly. The average duration of palliation was 4.3 months ± 0.5 (± standard error) in group I and 9.3 months ± 0.95 in group II. Complication rate was 4% in group I and 3.4% in group II. Parameters affecting results were found only in group I. Factors that could negatively affect the immediate success rate included annular size of the tumor basis more than two thirds of the circumference, tumor localization at the upper third of the esophagus, and recurrence after a nonlaser treatment. The average duration of improvement after initial success was affected only by the circumferential extension.
Fatal air embolism as a complication of laser‐induced hyperthermia
Authors: Schröder Tom M. , Puolakkainen Pauli A. , Hahl Juha , Rämö O. Juhani 
Published: March 2007

AbstractLaser‐induced hyperthermia is a new treatment modality for malignancies. When large tumors are treated with laser thermia, relatively high laser powers (4–6 W) must be used to accomplish destruction of the cancerous cells. Overheating and burning of the laser fibers and contact tips during laser thermia treatment must be prevented by using coaxial gas or fluid flow. The present report describes a case of fatal air embolism as a complication of laser thermia using coaxial gas. The authors warn all surgeons performing this procedure not to use coaxial air flow for cooling the contact tips because of the potential risk of air embolism.
Correlation of fluorescence emission with the plaque content and intimal thickness of atherosclerotic coronary arteries
Authors: Gaffney Edward J. , Clarke Richard H. , Lucas Alexandra R. , Isner Jeffrey M. 
Published: March 2007

AbstractThe use of fluorescence emission for guidance during laser angioplasty may be limited by the complexity of the emission from the broad range of atherosclerotic plaques normally encountered in diseased coronary arteries. Fatty, fibrous, and calcific plaque content as well as maximal intimal thickness were measured and correlated with fluorescence intensity ratios from the emission spectra for a broad cross‐section of atherosclerotic plaques from human necropsy specimens. Multiple and stepwise regression analysis was used to analyze intensity ratios of 13 wavelengths between 390 and 600 nm corresponding to regions of observed spectral structure. The level of correlation of the intensity ratios with fatty and calcific plaque content was found to be dependent on the complexity of the atherosclerotic lesion. The fluorescence emission was found to correlate well with both fibrous plaque content and intimal thickness, allowing the differentiation between normal and atherosclerotic samples. In conclusion, plaque characteristics can be assessed by fluorescence emission, although the successful implementation of spectroscopic guidance is dependent on the level of prediction error which may vary with tissue type.
In vitro comparison of thulium‐holmium‐chromium:YAG and argon ion lasers for welding of biliary tissue
Authors: Oz Mehmet C. , Bass Lawrence S. , Popp Howard W. , Chuck Roy S. , Johnson Jeffrey P. , Trokel Stephen L. , Treat Michael R. 
Published: March 2007

AbstractLaser welding offers several potential advantages over suture closure, including improved healing, lack of a nidus for stone formation, and greater speed and ease. We examined in vitro gallbladder cystic duct welds created by two different systems, the thulmium‐holmium‐chromium (THC):YAG (2,150 nm) and argon ion (488–514 nm) lasers, in an effort to define suitable parameters for tissue fusion. Mean bursting pressures for argon welds were 95 mm Hg at 1.5 W CW and 26 mm Hg at 1.5 W, 50 msec chopped delivery. For the THC:YAG laser, the mean bursting pressure for welds created with 300 mJ pulses was 45 mm Hg. Full‐thickness tissue fusion and limited collateral thermal damage were observed histologically for both the CW argon and pulsed THC:YAG welds. Examination of the suggested mechanisms of tissue fusion for these photothermal lasers suggests that increased duration of tissue heating at the appropriate temperature results in more extensive collagen crosslinking and a stronger weld.
Evaluation of a smoke evacuator used for laser surgery
Authors: Smith Jerome P. , Moss C. Eugene , Bryant Charles J. , Fleeger Alan K. 
Published: March 2007

AbstractA preliminary study was conducted to determine the effectiveness of a smoke evacuation system used in laser surgery. A 30 W medical CO2 continuous wave (CW) laser was used to make cuts in a pork chop to simulate smoke production during laser surgery. A commercially available smoke evacuation system was used to control the smoke from the simulated surgery. The smoke concentration was measured at 6 in and at 3 and 4 ft from site of laser interaction. The nozzle of the smoke evacuator was located at distances of 2, 6, and 12 in from the surgical site to measure the relative effectiveness of the control. Complete control of smoke was achieved when the nozzle was located at 2 in, but significant amounts of smoke escaped when the nozzle was located at 6 and 12 in. Suggestions for the use of the smoke evacuation system and areas for further study are given.
Experimental studies of the application of the Er:YAG laser on dental hard substances: II. Light microscopic and SEM investigations
Authors: Keller Ulrich , Hibst Raimund 
Published: March 2007

AbstractMany studies have been undertaken trying to use various laser systems as optical drills on dental enamel and dentin, but the high radiant exposure needed and subsequent high temperature rises lead to fractures of the hard substances and possible damages to the pulp. Compared to the other laser systems, the use of the Er:Yag laser has given encouraging results. Optical and scanning electron microscopy showed only minimal if any damage of the surrounding tissue.
Visible action spectrum for melanin‐specific selective photothermolysis
Authors: Margolis Randall J. , Dover Jeffrey S. , Polla Luigi L. , Watanabe Shinichi , Shea Christopher R. , Hruza George J. , Parrish John A. , Anderson R. Rox 
Published: March 2007

AbstractThe skin of black and albino guinea pigs was irradiated with single, 750 nsec‐long laser pulses at 435, 488, 530, and 560 nm in order to determine an action spectrum for the gross threshold response of immediate epidermal whitening. In addition, the immediate and delayed gross and histologic changes induced at, above, and below the threshold radiant exposures at all four wavelengths were studied. The action spectrum in the black guinea pigs was consistent with the reported absorption spectrum of DOPA‐melanin. Histologically, there was epidermal damage immediately after radiant exposures at and above threshold at all four wavelengths. In addition, radiant exposures greater than threshold caused an immediate decrease in stainable epidermal pigment that was most marked at 435 and 488 nm. The healing response was also wavelength‐ and dose‐dependent. Seven days after above‐threshold exposures, there was little epidermal pigment in the 435 nm specimens. As wavelength increased, there was progressively more pigment, and in the 560 nm specimens, the epidermal pigment was equivalent to that seen in nonirradiated black guinea pig control specimens. Seven days after subthreshold radiant exposures, there was increased epidermal pigmentation and melanocytes at all four wavelengths. This was the most pronounced in the 435 nm specimens. There was no observable epidermal damage in albino guinea pig skin.
Comparative study of the “point‐by‐point technique” and the “scanning technique” for laser treatment of port‐wine stain
Authors: Mordon Serge R. , Rotteleur Guy , Buys Bruno , Brunetaud Jean Marc 
Published: March 2007

AbstractPhotocoagulation using the argon laser has been proven to be an effective method for the treatment of port‐wine stains (PWS). However, it is very difficult to reproduce the parameters of laser treatment. This leads to inaccurate energy dosages secondary to the difference in treatment patterns. The aim of this study was to compare the conventional point‐by‐point technique (PT) for PWS treatment against a new scanning technique (ST) using a device called “Hexascan” (PREIN & Partners, Ferney‐Voltaire, France). A total of 249 patients (171 females and 78 males) using the argon laser have been studied in a retrospective study. Clinical results are presented.For each technique, blanching and hypertrophic scarring were examined. The results are classified into two groups: satisfactory and unsatisfactory. The clinical results show that the ST with the Hexascan is superior to the conventional PT. Scarring is drastically reduced because overdosage and overheating are avoided. Because of precisely controlled spot patterns, quality and homogeneity of blanching is improved. Treatment time can be reduced to 20% of that of the PT.
Cytotoxicity and mutagenicity of excimer laser radiation
Authors: Kochevar Irene E. 
Published: March 2007

AbstractExcimer laser radiation at 193 nm, 248 nm and 308 nm cause DNA photochemistry. The photobiological effects resulting from exposure of cells to 308 nm and 248 nm radiation appear to be the same as those obtained using low irradiance CW sources at similar wavelengths. This indicates that the high irradiances available from the excimer laser cause the same DNA photochemistry as the lower‐irradiance CW sources. Excimer laser radiation at 193 nm causes less cytotoxicity than predicted based on the DNA absorption spectrum. This may result from absorption of 193 nm radiation by protein present between the cell surface, and nuclear DNA, or from less efficient DNA photochemistry using 193 nm radiation. In vitro assays indicate that DNA‐damaging effects resulting in cytotoxicity decrease in the order 248 nm > 308 nm > 193 nm.
Macrophage responsiveness to light therapy
Authors: Young Steve , Bolton Peter , Dyson Mary , Harvey Wil , Diamantopoulos Costas 
Published: March 2007

AbstractMacrophages are a source of many important mediators of wound repair. It was the purpose of this study to see if light could stimulate the release of these mediators.In this study an established macrophage‐like cell line (U‐937) was used. The cells were exposed in culture to the following wavelengths of light: 660 nm, 820 nm, 870 nm, and 880 nm. The 820‐nm source was coherent and polarised, and the others were non‐coherent. Twelve hours after exposure the macrophage supernatant was removed and placed on 3T3 fibroblast cultures. Fibroblast proliferation was assessed over a 5‐day period.The results showed that 660‐nm, 820‐nm, and 870‐nm wavelengths encouraged the macrophages to release factors that stimulated fibroblast proliferation above the control levels, whereas the 880‐nm wavelength either inhibited the release of these factors or encouraged the release of some inhibitory factors of fibroblast proliferation.These results suggest that light at certain wavelengths may be a useful therapeutic agent by providing a means of either stimulating or inhibiting fibroblast proliferation where necessary. At certain wavelengths coherence is not essential.
Alteration of spectral characteristics of human artery wall caused by 476‐nm laser irradiation
Authors: Chaudhry Hina W. , Richards‐Kortum Rebecca , Kolubayev Tatiana , Kittrell Carter , Partovi Firooz , Kramer John R. , Feld Michael S. 
Published: March 2007

AbstractFluorescence spectroscopy is a promising new technique for discrimination of normal and atherosclerotic arterial tissues. It has been suggested that this technique be used as a guidance system for laser angiosurgery catheters; however, irradiation by 476‐nm light can change the spectroscopic properties of arterial tissue. We present studies that establish intensity levels and exposure times at which alterations in tissue spectral properties are minimal. We also investigate the nature of spectral alterations following exposure of normal human aorta to high intensities of 476‐nm laser light. Changes in laser‐induced fluorescence (LIF) are characterized by two prominent features: the peak fluorescence intensity decreases permanently, and the fluorescence lineshape changes in a largely reversible way. We relate these changes to alterations in individual tissue chromophores: permanent changes in absolute fluorescence intensity are due to irreversible changes in tissue fluorophores, reversible changes in fluorescence lineshape are due alterations in tissue absorbers. A simple kinetic model is used to describe the decrease in absolute fluorescence intensity.
Does low‐Intensity helium‐Neon laser irradiation alter sensory nerve active potentials or distal latencies?
Authors: Basford J. R. , Daube J. R. , Hallman H. O. , Millard T. L. , Moyer S. K. 
Published: March 2007

AbstractThe effect of 1 mW helium neon continuous‐wave (0.633 μm) laser irradiation on superficial radial sensory and median sensory nerve function was examined in a double‐blind, controlled study involving 40 volunteers. No differences in action potential amplitudes, distal latencies, or forearm skin temperatures were found between the treated and control groups either at the time of irradiation or at subsequent evaluations 15 and 30 minutes later. As a result, we are unable to confirm reports that low‐energy lasers of this power and wavelength alter nerve function.