bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular surgery of the basement membrane by the argon laser
Authors: Helmsworth Thomas F. , Wright Creighton B. , Schemer Scott M. , Schlemm Donna J. , Keller Stephen J. 
Published: March 2007

AbstractAlthough the argon laser is used successfully to weld a number of different tissues, the underlying chemical and cellular mechanisms for this process are not precisely defined. Consequently, a biochemical model has been developed in vitro using the welldefined extracellular matrix from the murine Engelbreth‐Holm‐Swarm (EHS) sarcoma. Control and experimental samples of EHS basement membranes were irradiated with a Trimedyne argon laser at 500–3,000 Joules/cm2 at 0°C. The samples were diluted into cold phosphate‐buffered saline and allowed to gel at 35°C. The time course of the gelation reaction was followed in a spectrophotometer at 360 nm. Irradiation reduced the absorbance 7.5–15% compared to controls and was independent of the dilution over a 10‐fold range. Gelation was also measured by determining the amount of protein by the Bradford assay that could be collected by centrifugation at 10,000g for 10 minutes. Argonirradiated samples had 30–40% less protein in the precipitate than the controls. The addition of 5 mM beta‐mercaptoethanol to the EHS extract blocked the effect of the laser on the gelation reaction. In addition, when gelation was carried out in the absence of calcium and magnesium, there were no differences between laser‐treated samples and controls. The basement membrane proteins were separated by electrophoresis through polyacrylamide gels under denaturing plus reducing or denaturing and non‐reducing conditions. No differences in the polypeptide composition were noted between irradiated and control samples using either Coomassie‐ or silver‐staining techniques. The irradiated and control samples were also analyzed on 1.5% agarose gels in 10 mm Tris‐HCl, pH 8 containing 0.1% SDS. Both samples produced a single Coomassie‐positive band, but the control migrated at 0.5 and the irradiated sample at 0.6. In sum, the conformation of extracellular matrix proteins can be altered by the argon laser at welding energies at low temperatures, even though no new covalent interactions were observed.
Endometrial ablation for the treatment of menorrhagia: A comparison of patients with normal, enlarged, and fibroid uteri
Authors: Lomano Jack 
Published: March 2007

AbstractOne hundred sixty‐one patients underwent endometrial ablation with the Nd:YAG laser for the treatment of refractory menorrhagia. Patients were divided into one of three groups: those with a normal‐sized uterus; those with an enlarged uterus (> than 10 cm); and those with uterine fibroids, which had been documented clinically, ultrasonographically, or by a combination of hysteroscopy and laparoscopy or by one or the other. All patients were considered candidates for hysterectomy. Both preoperatively and postoperatively, patients monitored their menstrual cycles and evaluated their flow according to predetermined categories of amenorrhea, light flow, normal flow, heavy flow, and severe flow. After treatment, 68% of patients with normal‐sized uterus and 91% of patients with an enlarged uterus (> than 10 cm) and 88%of patients with uterine fibroids became amenorrheic or had light flow. None of the patients in this last group have had to undergo hysterectomy. This study indicates that the patient with an enlarged or fibroid uterus may not have contraindications for endometrial ablation. Endometrial ablation may be effective in at least temporarily controlling bleeding in those patients with enlarged or myomatous uterus.
Influence of probe motion on laser probe temperature in circulating blood
Authors: Hehrlein Christoph , Splinter Robert , Littmann Laszlo , Tuntelder Jan R. , Tatsis George P. , Svenson Robert H. 
Published: March 2007

AbstractThe purpose of this study was to evaluate the effect of probe motion on laser probe temperature in various blood flow conditions. Laser probe temperatures were measured in an in vitro blood circulation model consisting of 3.2 mm‐diameter plastic tubes. A 2.0 mm‐diameter metal probe attached to a 300 μm optical quartz fiber was coupled to an argon laser. Continuous wave 4 watts and 8 watts of laser power were delivered to the fiber tip corresponding to a 6.7 ± 0.5 and 13.2 ± 0.7 watts power setting at the laser generator. The laser probe was either moved with constant velocity or kept stationary. A thermocouple inserted in the lateral portion of the probe was used to record probe temperatures. Probe temperature changes were found with the variation of laser power, probe velocity, blood flow, and duration of laser exposure. Probe motion significantly reduced probe temperatures. After 10 seconds of 4 watts laser power the probe temperature in stagnant blood decreased from 303 ± 18°C to 113 ± 17°C (63%) by moving the probe with a velocity of 5 cm/sec. Blood flow rates of 170 ml/min further decreased the probe temperature from 113 ± 17°C to 50 ± 8°C (56%). At 8 watts of laser power a probe temperature reduction from 591 ± 25°C to 534 ± 36°C (10%) due to 5 cm/sec probe velocity was noted. Probe temperatures were reduced to 130 ± 30°C (78%) under the combined influence of 5 cm/sec probe velocity and 170 ml/min blood flow. In conclusion, laser‐heated metal probe temperatures are reduced by probe motion in blood independent of temperature losses due to blood flow. Probe motion in combination with blood flow markedly decreases probe temperatures.
193 nm excimer laser ablation of bone
Authors: Lustmann Joshua , Ulmansky Mario , Fuxbrunner Amihay , Lewis Aaron 
Published: March 2007

AbstractThe argon fluoride excimer laser is investigated as a cutting‐ablating tool for bone surgery. Quantitative measurements are presented for various fluences of laser energy and number of pulses. Histological data are presented that demonstrate the minimal damage to the surrounding material from the laser interaction. Comparisons are made for non‐decalcified and decalcified bone. The differences observed, as a function of decalcification in the fluences required for specified depth penetration, are noted and a possible explanation is suggested.
Design and evaluation of a fiberoptic fluorescence guided laser recanalization system
Authors: Garrand Timothy J. , Stetz Mark L. , O'Brien Kenneth M. , Gindi Gene R. , Sumpio Bauer E. , Deckelbaum Lawrence I. 
Published: March 2007

AbstractCurrent angioplasty techniques for recanalization of totally occluded arteries are limited by the inability to cross the occlusion and by the risk of perforation. A fiberoptic fluorescence guided laser recanalization system was developed and evaluated in vitro for recanalization of 17 human femoral or tibial totally occluded arterial segments (length 1.9–6.8 cm, diameter 2.5–6.0 mm). A 400 or 600 μm silica fiber was coupled to a helium‐cadmium laser (λ = 325 nm) for fluorescence excitation and to a holmium: YAG laser (λ = 2.1 μm) for tissue ablation. Fluorescence was recorded during recanalization after every other holmium laser pulse. During recanalization, each arterial segment was bent 30–90 degrees with respect to the fiber to simulate arterial tortuosity. Ablation continued with fiber advancement as long as the fluorescence confirmed that the target tissue was atherosclerotic. Arterial spectra were classified as normal or atherosclerotic by an on‐line computerized fluorescence classification algorithm (sensitivity 93%, specificity 95%). Normal fluorescence necessitated redirection of the fiber > 30 times per segment to continue recanalization. Fifteen of 17 totally occluded arteries had multiple recanalization channels created following total energy delivery of 40–1,016 Joules per segment with no angiographic or histologic evidence of laser perforation. Two heavily calcified arterial occlusions were not recanalized due to inhibition of holmium: YAG laser ablation by the recording of normal fluorescence spectra. Therefore, this fluorescence guided laser recanalization system appears safe and effective for recanalization of totally occluded arteries and merits in vivo evaluation. However, the lower sensitivity of fluorescence detection of heavily calcified plaques may limit the efficacy (but not safety) of fluorescence guided recanalization of heavily calcified occlusions.
A new concept for a realtime feedback system in angioplasty with a flashlamp pumped dye laser
Authors: Scheu Manfred , Kagel Henning , Zwaan Martin , Lebeau Annette , Engelhardt Ralf 
Published: March 2007

AbstractThe feasibility of using a pulsed dye laser in angioplasty for detection and disintegration of calcified plaques was studied in vitro. A flashlamp—pumped dye laser (495 nm, 2 μs) was used as the exciting source for laser‐induced‐fluorescence (LIF) signals. Spectral data in the 520 nm to 800 nm region of normal intima, calcified plaque and fibro‐fatty plaques were analyzed with an optical multichannel analyzer, using the same fiber for energy delivery and fluorescence diagnostic. Good signal to noise ratio and different spectra for different specimens were obtained within only 2 μs. The spectral difference is caused by selective reabsorption of oxyhemoglobin in the vessel wall. Time resolved LIF‐spectroscopy shows that the fluorescence intensity reaches its maximum value before the maximum laser intensity is delivered. Fluorescence analysis can be performed in less than 300 ns and therefore the laser can be controlled before plasma threshold is reached. The described in vito results can lead to a clinical useful feedbacksystem for energy control of μs lasers in angioplasty if the blood interference effects can be minimized by changing the laser excitation wavelength or staining the tissue.
Argon laser‐assisted anastomoses in medium‐size vessels: One‐year follow‐up
Authors: Kuroyanagi Yutaka , Taguchi Masakatsu , Yano Takashi , Jones Darrell N. , Shionoya Shigehiko 
Published: March 2007

AbstractLaser‐assisted anastomosis of medium‐size vessels can be performed with satisfactory short‐term patency. This study was undertaken to evaluate patency and structural integrity up to 1 year. An argon laser was used to make bilateral femoral arteriovenous anastomoses in 12 dogs compared to conventional suture method in another 8 dogs. These anastomoses were evaluated for patency and aneurysm formation at 1 hour; 1, 2, 4, and 8 weeks; and 12 months after surgery. All anastomotic sites were patent and without aneurysmal change or luminal narrowing at all harvesting intervals. Histologic examination revealed that within 1 month laser anastomotic sites were almost completely healed and without intimal hyperplasia. In suture anastomoses, foreign‐body reaction remained evident up to 1 year.Use of the argon laser for medium size vessel anastomoses resulted in excellent patency without aneurysm formation or intimal hyperplasia even in the long term. These data suggest promising clinical applications.
Argon laser initiated resin photopolymerization for the filling of root canals in human teeth
Authors: Potts Thomas V. , Petrou Athos 
Published: March 2007

AbstractThis work was undertaken to determine if 488 nm light is transmitted through dentin in quantities adequate to polmerize resin located several millimeters from the light source (an optical fiber). The spread of polymerization in a camphorquinone activated resin due to 488 nm light emanating from an opaque plastic canal was compared with light emanating from a canal of the same diameter in tooth dentin. Results indicated that irradiation of a resin‐filled chamber via an opaque canal generated a series of ellipsoidal forms, while irradiation via a root canal generated bullet‐shaped forms of much larger volume and weight. The base of these bullet‐shaped forms was flat against the dentin‐resin interface and surrounded the canal. These results indicated that 488 nm argon laser light was transmitted through dentin and could act to polymerize resin at a distance of several millimeters from the canal. Further experiments verified that resin in lateral canals of tooth roots was readily polymerized by 488 nm light applied at low power levels (50 mW). These experiments demonstrate the effectiveness of the argon laser in polymerizing light activated dental resins located within or adjacent to tooth dentin at distances up to several milimeters from the fiberoptic terminus. The flexibility and control that these procedures make possible in the obturation of root canals may lead to substantial improvements in endodontic therapy.
Micron‐resolution ranging of cornea anterior chamber by optical reflectometry
Authors: Huang David , Wang Jyhpyng , Lin Charles P. , Puliafito Carmen A. , Fujimoto James G. 
Published: March 2007

AbstractNoncontact, high resolution measurements of anterior eye structures using optical coherence domain reflectometry are described. Distances between intraocular structures are measured by directing a beam of short coherence length light onto the eye and performing an interferometric measurement on the optical group delay of reflected signals. Measurements of corneal thickness, corneal excision depth, and anterior chamber depth are demonstrated in vitro, and the location of tissue boundaries is resolved to within ± 2 μm. The full‐width‐half‐maximum longitudinal resolution is 10 μm. Sensitivities to reflected signals as small as 10−10 of the incident power are achieved by heterodyne detection.
Plasma‐mediated ablation of corneal tissue at 1053 nm using a Nd:YLF oscillator/regenerative amplifier laser
Authors: Niemz Mark H. , Klancnik Edward G. , Bille Josef F. 
Published: March 2007

AbstractPlasma‐mediated ablations were performed on human donor corneas with a short pulsed Nd:YLF laser system at 1053 nm. The pulses were 60 psec in duration at a repetition rate of 1.0 kHz. The laser beam was oriented perpendicular to the cornea surface. The threshold energy densities for ablation of epithelium, Bowman's membrane and stroma were measured. They were 6.1±1.8 J/cm2, 21.0±5.1 J/cm2 and 10.4±1.8 J/cm2, respectively. The mean rate of tissue removal at the stromal energy density threshold was about 1 μm per pulse. The walls of the laser excisions were smooth with distortions of less than 1 μm. A new quantitative model of plasma‐mediated ablation is introduced and found to closely predict the observed results. Based on the promising nature of the experimental data further investigations are planned in the use of a mode locked Nd:YLF laser as an alternative to excimer lasers for refractive corneal surgery.
Use of the pulsed Nd:YAG laser for intraoral soft tissue surgery
Authors: White Joel M. , Goodis Harold E. , Rose Charles L. 
Published: March 2007

AbstractApplication of a neodymium:yttrium‐aluminum‐garnet (Nd:YAG) laser was compared to conventional scalpel in dental soft tissue surgery. Two surgery sites on 29 patients were randomly selected and treated. An additional 41 patients were exclusively treated with the Nd:YAG laser. The surgical technique was then evaluated for periodontal pocket depths, degree of pain perceived, bleeding, inflammation, procedure time, and anesthesia. Surgical prognosis was made at the time of surgery and compared to actual healing 1 week and 1 month after surgery.No differences were observed between laser and scalpel surgery in terms of pocket depth reduction, postoperative pain, postoperative inflammation, and treatment time. However, operative and postoperative bleeding with laser surgery were significantly less than with conventional surgery. Anesthesia is required for scalpel surgery, the majority of laser‐treated sites evoked minimal pain without anesthesia.These results indicate that the Nd:YAG laser can be used successfully for intraoral soft tissue applications are well tolerated without anesthesia and minimal bleeding compared to scalpel surgery.
Post polymerization strength values of an argon laser cured resin
Authors: Blankenau R. J. , Powell G. L. , Kelsey W. P. , Barkmeier W. W. 
Published: March 2007

AbstractA hybrid composite resin, Prisma APH, and a microfilled composite resin, Silux Plus, were compared regarding diametral tensile strength values following conventional visible light polymerization and argon lasing. The time interval between resin polymerization and physical property testing ranged from 1 hour to 20 days. Results demonstrated considerable mean tensile strength value variation in the earlier phases of the study with a lessening of the differences between the tensile strengths achieved by each method of polymerization as the 20 day interval was approached. It was concluded that composite resin testing protocols should be lengthened to be able to fully assess the effects of the widely variant, time dependent mean test results.
Laser‐assisted microvascular anastomosis using CO2 and KTP/532 lasers
Authors: Samonte Bernadette R. , Fried Marvin P. 
Published: March 2007

AbstractThe milliwatt carbon dioxide (CO2) laser has been shown to be an effective device for performing laser‐assisted microvascular anastomosis (LAMA) with consistently high patency rates, minimal tissue disruption, and rapid surgical time as well as the potential for reduced inflammation due to fewer foreign bodies (sutures) in the wound. The purpose of this investigation was to determine the feasibility of using the potassium titanyl phosphate (KTP) laser to perform LAMA and to compare it to CO2 LAMA in both arteries and veins. Patency rates, inflammatory response, and course of healing were evaluated through histological analysis.Twenty‐eight rats were divided into two groups, which underwent either CO2 or KTP LAMA and then were sacrificed at 3 days, and 1, 2, 4, 8, and 12 weeks postoperatively. Patency rates for arteries and veins were comparable for both wavelengths (CO2: 100% for arteries, 93% for veins; KTP: 93% for arteries, 93% for veins). Histological grading of inflammation and fibrosis showed no significant difference between the two groups.This study demonstrated the efficacy of using the KTP/532 laser in performing LAMA. We found the KTP and CO2 LAMA to have comparable patterns of tissue damage and course of healing. Although this experiment did not investigate the mechanism(s) of tissue welding, our results suggest that successful LAMA may be independent of wavelength.
Alternative lasers for endoscopic surgery: Comparison of pulsed thulium‐holmium‐chromium:YAG with continuous‐wave neodymium:YAG laser for ablation of colonic mucosa
Authors: Bass Lawrence S. , Oz Mehmet C. , Trokel Stephen L. , Treat Michael R. 
Published: March 2007

AbstractPrecise and controllable tissue vaporization is essential for minimizing risk in removal of sessile polyps from the lumen of thin walled gastrointestinal organs such as the colon. We compared the ablative efficiency on canine colonic mucosa of the THC:YAG laser with the clinically employed cw Nd:YAG laser. Fresh canine colon was treated with a progressive dose schedule using each laser at several enery/power densities. Ablation depth was measured on fresh tissue and thermal (non‐ablation or coagulative) damage examined histologically. The THC:YAG ablation rates were 13.7 ± 0.8 and 10.2 ± 0.4 μm/J at 55 and 85 J/cm2, respectively. The Nd:YAG laser generated 3.7 ± 0.3, 2.8 ± 0.1, and 3.6 ± 0.2 μm/J at 4,460, 5,095, and 5,730 W/cm2, respectively. There was a significant (P< 0.001) difference among the THC:YAG ablation rates and between the THC: YAG and Nd:YAG ablation rates (ANOVA). The THC:YAG laser craters had significantly less collateral thermal damage than Nd:YAG. The pulsed THC:YAG laser should have an important clinical role since its use could reduce the risk of perforation in endoscopic laser procedures such as the removal of sessile polyps.
Studies in fiber guided excimer laser surgery for cutting and drilling bone and meniscus
Authors: Dressel Martin , Jahn Renate , Neu Walter , Jungbluth Karl‐Heinz 
Published: March 2007

AbstractOur experiments on transmitting high‐power excimer laser pulses through optical fibers and our investigations on excimer laser ablation of hard tissue show the feasibility of using the excimer laser as an additional instrument in general and accident surgery involving minimal invasive surgery. By combining XeCl‐excimer lasers and tapered fused silica fibers we obtained output fluences up to 32 J/cm2 and ablation rates of 3 μm/pulse of hard tissue. This enables us to cut bone and cartilage in a period of time which is suitable for clinical operations. Various experiments were carried out on cadavers in order to optimize the parameters of the excimer laser and fibers: e.g., wavelength, pulse duration, energy, repetition rate, fiber core diameter. The surfaces of the cut tissue are comparable to cuts with conventional instruments. No carbonisation was observed. The temperature increase is below 40°C in the tissue surrounding the laser spot. The healing rate of an excimer laser cut is not slower than mechanical treatments; the quality is comparable.
Laser beam diameter for port wine stain treatment
Authors: Keijzer Marleen , Pickering John W. , van Gemert Martin J. C. 
Published: March 2007

AbstractOptimal port wine stain treatment requires the selective absorption of light by the ectatic blood vessels. We investigated whether deeper blood vessels can be coagulated, without damaging other cutaneous structures, by varying the laser beam diameter. The penetration of the light was simulated with a random walk (Monte Carlo) program. Scattering of the light plays a major role: practically all light that is absorbed in a blood vessel in the dermis is scattered light. In the epidermis, where the distribution is more centered, a larger beam diameter does not increase the energy density as much as deeper within the dermis where the blood vessels lie and where the light is totally diffuse. Increasing the laser beam diameter from 200 μm to 1 mm or more, makes a typical blood vessel absorb 2.5 times more energy, while the energy absorbed by the epidermis remains the same. The larger the laser beam diameter the better the treatment.
Preliminary results of intraoperative excimer laser angioplasty: Phase 1: An adjunct to coronary artery bypass surgery
Authors: Frazier O. H. , Diethrich Edward B. , Johansson Bo , Conger Jeff L. , Burnett Clay M. , Bylock Anders , Kadipasaoglu Kamuran A. 
Published: March 2007

AbstractThe excimer laser underwent phase I clinical trials at three centers to determine its safety for intraoperative coronary laser angioplasty as an adjunct to coronary artery bypass grafting. A 308‐nm Xenon‐Chloride, pulsed‐wave excimer laser was used to perform angioplasty in 30 patients undergoing coronary artery bypass surgery. Forty vessels (30 patients) were treated, in which the extent of occlusion ranged from 30% to 100%, with complete occlusion in 40% of all vessels. Improvement in vessel luminal caliber was achieved in 33 (79%) vessels, with perforations occurring in 4 (12%) vessels, 2 of which required surgical repair. The lumens of the remaining 8 (19%) vessels were not enlarged, and 2 (5%) of these vessels were perforated. Luminal enlargement was most often achieved in totalled occluded vessels in which 16/17 (94%) were recanalized. No patients died within 30 days post‐operatively. Five patients demonstrated biochemical and electrocardiographic evidence of myocardial injury 48 hr postoperatively, and one patient died of cardiac arrest 139 days postoperatively. On the basis of these results, we believe that excimer laser angioplasty can be performed safely to improve coronary luminal patency, even in totally occluded vessels, in an operative setting. The long‐term value of this procedure remains to be elucidated.