bluuebunny/crossref_metadata_2025_split huggingface dataset:
A study on the possible involvement of nonlinear mechanism of light absorption by HpD with Nd: YAG laser
Authors: Marchesini Renato , Melloni Elsa , Fava Giannino , Pezzoni Gabriella , Savi Giuseppina , Zunino Franco , Docchio Franco 
Published: March 2007

AbstractThe purpose of this study was to investigate whether excitation of porphyrin could be related to nonlinear mechanisms of absorption of porphyrin itself or of the medium in which porphyrin is embedded.This possibility was proposed as an explanation for results of previous experiments where a Nd:YAG laser was used. An MS‐2 sarcoma transplanted into the hind pad of BALB/c mice was used as the experimental tumor model. Mice were given HpD i.v. (25 mg/kg) 24 h before exposure to light delivered from an IR laser (1,060 nm). Since at dose‐rates ranging between 600 and 1,200 mW/cm2the thermal effect tended to mask the nonlinear effect, the temperature of the limb of mice was kept cold by running water. Irradiation performed under cooling conditions did not show any tumor growth inhibition. Experiments in vitro performed on HT‐29 cells by a continuous wave (CW) or pulsed (Q‐switch) Nd: YAG laser indicated no appreciable difference in DNA synthesis between irradiated and nonirradiated cells.Our results did not evidence nonlinear mechanisms of absorption by HpD with Nd:YAG laser both in CW and pulsed (nanosecond range) modes.Whether this effect should occur, in any case it is unlikely to be suitable to induce a photodynamic effect due to its low efficiency. Nd: YAG laser could induce a heating related effect, which can improve the therapeutic efficacy of PDT.
Laryngo‐tracheal laser surgery and general anesthesia
Authors: Thode Susan A. 
Published: March 2007

AbstractThe use of the carbon dioxide laser in treatment of laryngo‐lracheal lesions is extremely effective when combined with general anesthesia. However, the potential for intraoperative complication is increased due to a pathological reduction in the size of the airway and the presence of an endotracheal tube. To avoid the hazard of endotracheal tube ignition, specific techniques are employed.
Mid‐infrared fiber optics
Authors: Fuller Terry A. 
Published: March 2007

AbstractFiber optics for carbon dioxide laser surgery have been in developmental research for the past ten years. An up‐to‐date presentation of infrared fiber optics as they pertain to laser surgery is presented. Optical properties such as intrinsic and extrinsic electronic absorption, multiphonon absorption, and scatter mechanisms are discussed. Real‐world considerations for materials selection and fabrication techniques for both crystalline and glassy fiber optics give the reader a perspective regarding the stage of development of these devices. Data are presented indicating transmission ranges and absorption coefficients for both bulk materials and fabricated fiber optics. The conclusions are drawn based on the needs of the clinician as they relate to the degree of existing technology.
Photodynamic therapy: The state of the art
Authors: Carruth J. A. S. 
Published: March 2007

AbstractPhotodynamic therapy is a new and exciting treatment modality for many forms of localised malignant disease. A considerable amount of laboratory and clinical research has been carried out using the tumour sensitiser haematoporphyrin derivative activated by red light at a wavelength of 630 n commonly produced by either an argon/dye laser or a pulsed gold vapour laser. It appears certain mat continuing research will produce better tumour sensitisers activated by different wavelengths of light, but it will be several years before any new drug/light combination is ready for clinical trials.This paper presents an overview of the current situation and a summary of some of the exciting results that are being obtained in clinical trials throughout the world.
HeNe laser irradiation delivered transcutaneously: Its effect on the sciatic nerve of rats
Authors: Nissan M. , Rochkind S. , Razon N. , Bartal A. 
Published: March 2007

AbstractFor our study of the effect of low energy laser irradiation (LELI) on living tissue we used HeNe laser on rats. The exponential absorption was reaffirmed in the living tissues overlying the sciatic nerve.An optimal range of energy between 3.5 and 7 J—associated with energy concentration of 4–10 J/cm2 delivered transcutaneously—was found to cause a significant increase in action potential in the sciatic nerve. The effect lasted for more than 8 months after the irradiation session.
Use of the CO2 laser for malignant disease of the oral cavity
Authors: Duncavage James A. , Ossoff Robert H. 
Published: March 2007

AbstractThe CO2 laser has provided the otolaryngologist/head and neck surgeon with a valuable addition in the diagnosis and treatment of malignant disease of the oral cavity. It is also helpful in the treatment of the premalignant clinical leukoplakias of the oral cavity. Carcinoma in situ has been diagnosed and treated successfully with the CO2 laser. The T1 carcinomas of the tongue, floor of mouth, and tonsil can be successfully managed with the CO2 laser. It also offers the patient a relatively painless method of debulking large obstructing tumors. Other advantages of the CO2 laser include hemostasis, precise visualization, and less edema and pain than the conventional techniques.
Clinical report: Laser myocardial revascularization
Authors: Mirhoseini Mahmood , Cayton Mary M. , Shelgikar Suhas , Fisher John C. 
Published: March 2007

AbstractA significant number of patients with ischemic heart disease are not candidates for coronary artery bypass or percutaneous transluminal angioplasty and do not respond to medical management. This group includes those who have diffuse coronary artery disease, those with poor ventricular function, and those who have had poor results from previous surgery.Developing a method to directly revascularize the myocardium by creating channels through the ventricular wall has challenged many investigators. Early methods, including needle acupuncture, were successful in the acute phase, but long‐term patency could not be achieved. Closure of the channels was due to fibrosis and scarring.Experiments in our laboratory demonstrated that myocardial channels, made with the CO2 laser, remained patent up to five years. Histopathologic examination of the channels showed minimal damage to the surrounding cells in the acute phase. Studies at intervals of two months to two years showed patent endothelialized channels, with no evidence of fibrosis. Channels created in the myocardium protected the ventricle against an ischemic event when the left anterior descending branch of the coronary artery was ligated.Clinical experience with direct myocardial revascularization by CO2 laser indicates it may be a viable method of treating those patients with ischemic heart disease who are not candidates for other forms of management. The treatment and early postoperative follow‐up in one patient are described.
Current laser dentistry
Authors: Goldman Leon , Goldman Bernard , Lieu Neal Van 
Published: March 2007

AbstractCurrent laser dentistry since our initial studies in 1964 is reviewed. Three areas are considered: routine dental office practice, tooth restoration, and oral surgery. For tooth restoration and oral surgery, CO2 and neodymium:YAG lasers are used and lasers are used in photodynamic therapy for oral cancer. Dental office practice today is concerned mostly with uncontrolled studies of biostimulation and requires more basic research and controlled clinical studies. The laser industry in the United States should take a more active interest in defining the applications of lasers in dentistry.
Hyperthermic potentiation of photodynamic therapy employing photofrin I and II: Comparison of results using three animal tumor models
Authors: Waldow Stephen M. , Henderson Barbara W. , Dougherty Thomas J. 
Published: March 2007

AbstractHyperthermia induced by a microwave source (2,450 MHz) was used alone and in combination with photodynamic therapy (PDT) to treat the SMT‐F, EMT‐6, and RIF animal tumors in vivo. PDT was administered using either Photofrin I or II as the photosensitizer and an argon‐pumped tunable dye laser (630 nm) as the light source. Greater than additive increases in long‐term tumor control were achieved when hyperthermia was given immediately post‐PDT in the SMT‐F and RIF tumor systems. Only additive (or independent) increases in tumor control were achieved when hyperthermia was given immediately before PDT in all these tumor systems and when heat was applied post‐PDT using the EMT‐6 tumor.In a series of experiments using the SMT‐F tumor, it was observed that decreases in PDT drug or light doses could be offset (in terms of tumor control) by the addition of a subsequent heat treatment. This result, along with others presented, indicates the clinical potential of PDT and hyperthermia as adjuvant cancer modalities.
New techniques for reducing the thermochemical damage in the course of laser surgery
Authors: Armon Eliahu , Laufer Gabriel 
Published: March 2007

AbstractNew techniques were proposed for reducing the damage incurred to living tissues owing to temperature rise induced by surgical lasers. Precooling of the tissue and spatial filtering were evaluated numerically and were shown to be most effective in most surgical procedures. Application of pulse trains was also evaluated numerically and optimal operating conditions were identified.
CO2 laser surgery of intramedullary spinal cord tumors
Authors: Heppner Fritz , Ascher Peter W. , Holzer Peter , Mokry Michael 
Published: March 2007

AbstractOf a total of 580 patients suffering from expanding spinal disease, 15 cases of intramedullary lesions were dealt with by the use of the CO2 laser. Sharp cutting and precisely controlled depth effect are the advantages that make the CO2 laser very useful for surgery within the spinal cord. In tumors of tough consistency the neoplastic tissue is usually sharply demarcated, in which case the CO2 laser is used for dissection along this borderline, at an output energy of 15–20 W, infocus, continuous wave (CW). In tumors of soft consistency, characterized by a more‐or‐less diffuse zone of invasion—eg, glioblastomas—vaporization [20 W, out‐of‐focus, CW] and removal by ultrasound‐microsuction is recommended. This procedure should advance layer by layer until normal looking tissue is reached. In this way intramedullary tumors may be removed with minimal side effects. The postoperative course involves less pain and less edematous reaction, and the rehabilitation time is shortened compared with conventional surgical treatment. In benign neoplasms long‐term results are good; malignant cases require additional x‐ray treatment and chemotherapy.
Electron microscopy of CO2‐laser‐induced effects in human fibrocartilage
Authors: Whipple Terry L. , Marotta Joseph J. , May Thomas C. , Caspari Richard B. , Meyers John F. 
Published: March 2007

AbstractPrevious reports of effects of CO2 laser energy on human fibrocartilage suggest thermal injury extends to a depth of approximately 70 μm from the target surface with power settings of 35 W and exposure times of 0.5 seconds. The present study was undertaken to look for more subtle evidence of thermal alteration of human fibrocartilage treated with CO2 laser irradiation.Fifteen human menisci were irradiated at power settings of 10, 20, and 30 W with exposure times of 0.1 and 0.5 seconds. The specimens were immediately fixed and sectioned for electron microscopic examination. Loss of a normal cross banding, and marginal clarity of individual collagen fibers were observed in the extracellular matrix and were observed at distances up to 300 μm from the exposed tissue surface. In addition, cellular changes at similar tissue depth consisted of cell membrane invaginations, clumping of nuclear chromatin, breakdown of endoplasmic reticulum architecture, and loss of mitochondria and Golgi complexes from the cytoplasm were observed.This study demonstrates deeper penetration of a radiation that was previously appreciated by light microscopy in irradiated human fibrocartilage, although the implications with respect to contraside viability and healing potential of the tissue in vivo is not known.
Acoustic nerve tumor surgery before and since the laser: Comparison of results
Authors: Cerullo Leonard J. , Mkrdichian Edward H. 
Published: March 2007

AbstractA random computer selection of 21 patients who underwent 28 operations for acoustic neurinoma between 1974 and 1980 using conventional methods, including the operating microscope and microtechnique, was compared with a cohort of 22 patients who underwent 25 operations between 1980 and 1984 utilizing a carbon dioxide laser. Completeness of tumor removal, anatomical and functional preservation of the facial nerve, preservation of hearing, morbidity and mortality, average hospital stay, and eventual outcome were used as markers and were compared. Utilizing P values, the study demonstrated a significantly superior outcome, and as a result a better life quality, in patients who were operated on utilizing a CO2 laser in addition to conventional microsurgical technique.
Examination of tooth pulp following laser beam irradiation
Authors: Serebro Leslie , Segal Trevor , Nordenberg Daniel , Gorfil Colin , Bar‐Lev Moshe 
Published: March 2007

AbstractAn attempt was made to determine the maximum amount of laser energy which could be utilized without impairing pulpal vitality. Forty rat molar teeth were irradiated in vivo; the Sharplan CO2 laser modality, focused to a 0.2‐mm‐diameter spot size was used. The energy output was varied by changing the power and/or the pulse duration. Subsequent histological examination of the irradiated teeth showed that the duration of exposure was more significant than the power. A pulse of 0.2 sec/10 W appears to be the safety limit in preserving pulpal vitality.
Morphological and surface temperature changes in femoral arteries following laser irradiation
Authors: Sorensen Elsie M. B. , Thomsen Sharon , Welch A. J. , Badeau Albert F. 
Published: March 2007

AbstractA low‐power carbon dioxide laser was to irradiate rat femoral arteries under the same conditions required to anastomose severed human arteries by thermal coagulation. Mean surface temperature changes were measured at the site of laser impact with the artery to evaluate the resultant histopathological changes as a function of laser power. More severe thermal coagulative changes, necrosis, and swelling resulted with increased laser power. Comparison of the temperature‐time relationships showed that the peak surface temperature rise at the surface of these arteries was about 25°C for one pulse at 200 mW laser power, compared to an approximate 7°C rise for one pulse at 120 or 150 mW laser power. Increase in the surface temperature resulted in an increased severity of histopathological injury. These results showed that necrosis of medial layer smooth muscle cells occurred beyond the laser exposure site, suggesting that heat conduction could result in significant damage to reconnected vessel and could be a factor in the formation of a weak bond or an aneurysm.
Pulmonary procedures assisted by optosurgical and electrosurgical devices: Comparison of damage potential
Authors: Locicero Joseph , Frederiksen James W. , Hartz Renee S. , Michaelis Lawrence L. 
Published: March 2007

AbstractElectrosurgical devices have been used widely in thoracic surgery to assist in dissection and to reduce hemorrhage. Recent experimental data have shown that lasers may be used to resect and control small air leaks while conserving normally functioning lung. This investigation quantitates the amount of damage produced by the electrosurgical unit (ESU), the carbon dioxide laser (CO2), and the neodymium: YAG laser (YAG) compared to standard suture (SU) techniques. Six dogs were anesthetized, intubated, and ventilated. The left chest was opened and the lower lobe exposed, where four sets of lesions were created using each device. All lesions were visually similar to those lesions that would be created for sealing at the time of a pulmonary resection. The lesions were harvested immediately following wounding as well as at 1, 3, and 6 week intervals. They were examined histologically and ranked from least to most damage produced at each interval. A grading system (0–4+) was also devised to compare the injury to simultaneously harvested normal lung. Immediately following injury, histologic ranking was: CO2 (2+), suture (2+), ESU (3+), YAG (4+). By 6 weeks, the suture damage had become minimal and the ranking was: suture (1+), CO2 (2+), YAG (4+), ESU (4+). The ESU consistently produced more extensive damage than any other device. It appears that the most suitable long‐term adjunctive devices to assist in pulmonary surgery are suture and the CO2 laser. The YAG laser may have specific indications in circumstances when significant blood loss may be encountered. ESU usage should be minimized when attempting to preserve functioning lung tissue.
Is an anesthesiologist's presence justified during therapeutic laser endoscopy?
Authors: Lichtiger Monte , Russin David J. 
Published: March 2007

AbstractDiagnostic endoscopy has generally been done under intravenous sedation. Diazapam and meperidine are the two most frequent drugs used. Even though these drugs produce sedation, analgesia, and amnesia, they do not provide a quiet field. Therapeutic laser endoscopy requires a quiet field. We conclude that an anesthesiologist is needed at the head of the table. Despite the increased cost of the procedure, the anesthesiologist is able to tailor the anesthesia to fit the needs of both the patient and the endoscopist.
Resection of abdominal hollow organs by laser
Authors: Skobelkin Oleg K. , Breckov Eugeny I. , Bashilov Vitaly P. , Korepanov Valentine I. , Litwin Gregory D. , Smoljaninov Michael V. , Malyshev Boris N. , Salyuk Victor A. 
Published: March 2007

AbstractDuring a ten‐year period 642 abdominal hollow organ resections have been performed by means of a new, original technique — that is, CO2 laser irradiation combined with specially designed instrumentation. This resulted in a remarkable decrease in postoperative morbidity and mortality. The article describes the laser procedure.
Comparison of the optical transmission properties of pulses and continuous wave light in biological tissue
Authors: LaPlant M. , Parker J. , Stewart B. , Waner M. , Straight R. C. 
Published: March 2007

AbstractThe purpose of this study is to compare the optical transmission of the pulsed gold vapor laser (628 nm) to that of the continuous wave argon‐pumped dye laser (630 nm) in a homogenous tissue model. Gluteal muscle was taken from a rabbit, and sections of varying thicknesses were made. The tissue samples were positioned at the aperture of an integrating sphere. The laser light was passed through an optical attenuator, coupled to a 600‐μm fiber, and then directed onto the surface of the tissue. Transmitted light was collected by the integrating sphere. Light measurements were made with a radiometer. This procedure was repeated for samples of differing thickness using the gold vapor laser as the light source. The identical procedure was performed using the argon‐pumped dye laser. No significant difference was found in percent transmission of light using the gold vapor laser as compared to the argon‐pumped dye laser.
Silver oxide in YAG sclerostomy
Authors: March Wayne F. , Shaver Robert P. , Gherezghiher PhD Tseggai , Nordquist Robert E. 
Published: March 2007

AbstractYAG sclerostomy is a filtering procedure performed entirely with the neodymium:YAG laser through a goniolens as an alternative to trabeculectomy in the treatment of glaucoma. Extremely large pulse powers have been required in the past to complete the procedure. We found that an injection of silver‐stabilized protein intrasclerally prior to the procedure makes it possible to perform the procedure with low total power.
Hyperthermia from interstitial laser irradiation in normal rat brain
Authors: Elias Zev , Powers Stephen K. , Atstupenas Eliot , Brown J. Tony 
Published: March 2007

AbstractThis study examined both the effect of variations in optical fiber tip and in light wavelength on laser‐induced hyperthermia in rat brain. Normal rat brains were exposed to argon laser light (454–514.5 nm) delivered through an intracerebral end‐emitting (bare‐tipped) or a diffusion‐emitting (sapphire‐tipped) optical fiber probe. Interstitial thermister probes recorded temperatures after thermal equilibration at varying distances from the emitting source. The end‐emitting fiber produced significantly (P < 0.05) higher elevations in tissue temperature than the diffusion‐emitting fiber at the same laser power output. This is due to the smaller surface area (1.2 mm2 versus 7.8 mm2) of the end‐emitting fiber, which results in a greater rate of energy delivery to tissue adjacent to the fiber tip.Changes in intracerebral temperature measurements were also recorded at similar distances from a diffusion‐emitting fiber at a continuous total laser power output of 150 mW for light wavelengths of 454–514.5 nm, 700 nm, and 750 nm and at a total laser output of 1.1 W for 1,060 nm. Variations in brain tissue temperature with distance from the laser emission source were compared for each laser group with the tissue temperature profile generated by a radiofrequency (wavelength 600–625 m) interstitial probe. Similar temperature changes were found for all visible wavelengths near the probe, suggesting that the thermal response of brain adjacent to an interstitial laser fiber is primarily dependent upon the rate of energy delivery and not upon wavelength. The thermal profile versus distance from the light source depends mostly upon the level of temperature rise near the interstitial laser fiber tip and not the wavelength of laser light used. These results have important implications in interstitial applications of laser for hyperthermia and photochemotherapy.
Thermal injury by laser pulses: Protection by heat shock despite failure to induce heat‐shock response
Authors: Polla B. S. , Anderson R. Rox 
Published: March 2007

AbstractPulsed lasers produce a variety of therapeutically useful effects in tissues by thermal mechanisms. In contrast with conventional hyperthermia, pulsed lasers rapidly induce extremely high temperatures confined to small areas within the tissues. It is not established, however, how cellular damage and repair responses differ between conventional and pulsed laser‐induced hyperthermia. We have addressed this question by examining the induction of cellular heat‐shock proteins (HSPs) and protection by heat‐shock response against pulsed laser vs conventional hyperthermia.Cultured human dermal fibroblasts at confluency were exposed to single 2‐μsec, 10.6‐μm‐wavelength pulses from a pulsed CO2 laser at radiant exposures between 0 and 1.3 J/cm2. Cell monolayers were directly exposed after removal of overlying medium. Positive control for the ability of the cells to synthesize of HSPs was obtained by heating the cells for 20 min in a water bath at 45°C or 47°C. The cultures were then labeled with L‐[35S] methionine (Met), and proteins analyzed by sodium dodecyl sulfate polyacrylamide and two‐dimensional gel electrophoresis 2 hr after exposure. The morphological alterations induced by laser or heat were similar under phase contrast microscopy. Conventional heating induced a heat‐shock response, with the appearance of HSPs 2 hours after heating. In contrast, synthesis of HSPs could not be detected following laser irradiation, even at exposures decreasing both cell viability and incorporation of [35S] Met into cellular protein. Pre‐exposure of cells to temperatures which induced synthesis of HSPs, however, significantly decreased cell death induced by subsequent laser irradiation.These data provide insight into the biological events induced by pulsed lasers at the cellular level. Synthesis of HSPs, although not induced by brief laser pulses, may play a role in protection against laser‐induced cell injury.