bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular, cellular, and tissue responses following photodynamic therapy
Authors: Gomer Charles J. , Ferrario Angela , Hayashi Naganobu , Rucker Natalie , Szirth Bernard C. , Murphree A. Linn 
Published: March 2007

AbstractPhotodynamic therapy (PDT) is being utilized in the treatment of a wide variety of malignant tumors. Results using PDT have been encouraging, and controlled clinical trials are currently being performed. The procedure exploits both the tumor‐localizing and ‐photosensitizing properties of hematoporphyrin derivative or its purified component, Photofrin II. When this porphyrin mixture is administered systemically, it is retained preferentially in tumor tissue as compared to surrounding normal tissue. Localized tumor destruction induced by PDT results from the photochemical generation of cytotoxic oxygen species within the tumor. This review will provide a summary of historical and current research pertaining to molecular, cellular, and tissue responses induced by PDT. Emphasis is placed on information related to the chemistry of current photosensitizers, subcellular targets, preclinical treatment parameters, and clinical responses following PDT.
Comparison of local tumor recurrence following excision with the CO2 laser, Nd:YAG laser, and argon beam coagulator
Authors: Lanzafame Raymond J. , Qiu Kang , Rogers David W. , Naim John O. , Caldwell Fred C. , Hall Freddy Perry, Darline , Hinshaw J. Raymond 
Published: March 2007

AbstractThis study compares the incidence of local tumor recurrence following primary excision with the CO2 laser, Nd:YAG laser (contact), Argon Beam Coagulator, or electrocautery. One hundred eight Fisher 344 rats with R3230AC mammary tumors (1.6 ± 0.04 [SD] cm diameter) were used. All animals were randomized into groups of similar tumor size. In groups C and CS, excision was performed with a Sharplan 1060 CO2 laser (TEMoo, 25 W, continuous wave [CW], 0.2‐mm spot size). Wounds in group CS were “sterilized” (0.5‐mm spot size, 25 W, CW) by gently heating the wound without causing blanching or charring. In group N, a 0.4‐mm contact Laser Blade± and a Cooper 8000 Nd:YAG laser at 20 W CW was used. In groups SA1 and SA2, tumors were excised with the scalpel, and hemostasis and wound “sterilization” were accomplished with the Bard System 6000 Argon Beam Coagulator (ABC) at 40 W and 4 liters/min argon gas flow in SA1 and 12liters/min in SA2. In group E, excision was accomplished at 40 W blend mode, 10 W spray mode. In group EA, excision was accomplished at 60 W cutting current, and hemostasis was achieved with the ABC. The animals were examined for evidence of recurrence for 34 days postoperatively. Mortalities were excluded from analysis. The incidence of recurrence was 11/14 (79%) in C, 6/16 (38%) in CS, 10/14 (71%) in SA1, 6/13 (46%) in SA2, 6/15 (40%) in N, 7/10 (70%) in EA, and 3/15 (20%) in E. Group E is statistically different (P < .01) from groups EA, C, and SA1. Group C was different (P < .01) from groups E, CS, and N. These results demonstrate an inverse relationship between tumor recurrence and local thermal effects at the surgical site. The ABC did not increase tumor recurrence. Contact YAG surgery was similar to CO2 laser excision and “sterilization.” An attempt to study the influence of gas flow and pressure on local tumor recurrence and metastases should be made.
Effects of blood flow on laser probe temperature in human arteries
Authors: Silverman Steven H. , Khoury Adib I. , Abela George S. , Seeger James M. 
Published: March 2007

AbstractLaser recanalization using metal capped fibers occurs by thermal vaporization of occluding plaque. However, little is known about the effects of blood and flow on the temperature of the laser probe or the arterial wall during lasing. To study this, probe and arterial wall temperatures were measured while a metal capped fiber, activated by an argon laser, was held stationary in a stenotic human peripheral artery. Arteries were perfused with saline and blood, and flow was varied from 0 to 140 cc/min. Probe temperatures were significantly higher in blood than in saline. However, the increased probe temperature achieved in blood was not transferred to the arterial wall. Increasing flow decreased probe temperature in both media, but again arterial wall temperatures were minimally affected. Thus, the presence of blood and flow may significantly affect heat generation and heat transfer during arterial recanalization using metal capped fibers.
Cellular effects of the pulsed tunable dye laser at 577 nanometers on human endothelial cells, fibroblasts, and erythrocytes: An in vitro study
Authors: Glassberg Edward , Lask Gary P. , Tan Elaine M. L. , Uitto Jouni 
Published: March 2007

AbstractThe 577‐nm flashlamp‐pumped tunable dye laser pulsed at 450 μs is rapidly becoming the treatment of choice for removal of portwine stains and other vascular ectasias. In this study, we examined the mechanisms of vessel destruction by determining the effects of laser irradiation on three types of primary target cells–erythrocytes, endothelial cells, and fibroblasts. Human endothelial cells and fibroblasts in microwell plates were irradiated at various energy densities with the laser, after which several aspects of cellular biology were determined, including (1) viability of cells by trypan blue exclusion test; (2) cell proliferation by [3H]thymidine incorporation; and (3) rate of protein synthesis using [3H]leucine incorporation as a marker. In endothelial cell cultures, both [3H]thymidine and [3H]leucine incorporations were inhibited at energy levels of 5–12 J/cm2 (P < 0.01). In fibroblast cultures, cell proliferation was similarly inhibited, while supratherapeutic energy density (⩾12 J/cm2) was required for inhibition of protein synthesis. The laser energy in the range of 5–8.5 J/cm2 had no effect on cell viability. Erythrocytes as target cells for laser energy demonstrated rapid, dose‐dependent lysis, as determined by release of free hemoglobin into culture medium. Addition of erythrocytes into a coculture with endothelial cells abolished the direct inhibitory effect noted in cultures when endothelial cells were present alone. The results of the latter experiment imply that erythrocytes are the primary target cell absorbing the laser energy at 577 nm. However, direct laser effects on endothelial cells may also contribute to the mechanisms of ablation of the vascular ectasias by the tunable dye laser at 577 nm.
Laser‐Assisted intestinal anastomosis
Authors: Vlasak Jerry W. , Kopchok George E. , White Rodney A. 
Published: March 2007

AbstractLaser‐assisted tissue fusion has been investigated as a new technology to enhance the healing of soft tissues. Laser fusion of intestinal anastomoses shows promise as a method to obtain primary healing while eliminating a foreign‐body reaction associated with the sutures. This paper reviews the experimental data that are available regarding laser‐assisted intestinal anastomoses and summarizes our experience using the CO2, Nd:YAG, and argon lasers to form fusions in small bowel.
Argon laser treatment of urethral stricture and vesical neck contracture
Authors: Adkins William C. 
Published: March 2007

AbstractThe physical characteristics of the argon laser wavelength allow a precise incision with excellent hemostasis and negligible heating of adjacent tissues resulting in less scarring. These qualities are used to advantage in the treatment of strictures. The argon laser was used to perform 13 internal urethrotomies and ten vesical neck incisions. The operative method used is similar to optical internal urethrotomy. The argon probe incises hemostatically, reducing the need for extensive fulguration of tissues at the operative site and thereby reducing the tendency for more scar tissue to form and compromise the operation. The same hemostasis reduces the need for postoperative indwelling urethral catheterization. Utility of the argon device in most instances allows treatment to be conducted on an outpatient basis without general anesthesia and without use of postoperative urethral catheters, yielding an effective, cost‐saving therapy.
Anastomosis of bypass grafts using a low‐powered CO2 laser
Authors: Frazier O. H. , Shehab S. Anne , Zirl Robert , Radovancevic Branislav , Nakatani Takeshi , Bossart Mattie I. , Parnis Steven M. 
Published: March 2007

AbstractThe purpose of this study was to evaluate the feasibility of using a low‐powered CO2 laser to perform end‐to‐side anastomoses of bypass grafts. The internal jugular veins of 13 domestic swine were removed and used as grafts to bypass their ligated carotid arteries. Each end of the vein graft was apposed to the artery with four to six temporary stay sutures, and a waveguide delivery CO2 laser with a power density of 900 mW/mm2 was used to perform the anastomoses, after which the sutures were removed. The animals were sacrificed postoperatively at five time intervals: 2 to 4 hours, 5 days, 1 month, 3 months, and 5 months. Of the 10 anastomoses studied at 2 to 4 hours, 70% were fully patent, none thrombosed, and 30% disrupted. Of the 16 anastomoses studied between 5 days and 5 months postoperatively, 88% were patent, 12% thrombosed, and none disrupted. None of the animals developed aneurysms at any stage of this investigation. Histologic analysis of acute studies revealed thermal damage such as charring of tissue, unraveling of the collagen fibrils, and the formation of microvacuoles. Within 3 months, the anastomotic sites showed localized healing with intimal fibromuscular proliferation and dense fibrous tissue. Good apposition of tissue was found to be of great importance in achieving patency of vessels in this procedure.
Effect of low‐energy laser irradiation on colony formation capability in different human tumor cells in vitro
Authors: Marchesini Renato , Dasdia Teresa , Melloni Elsa , Rocca Emilio 
Published: March 2007

AbstractFibroblasts and lymphocytes are the most widely used cells for studying the so‐called biostimulative effect of low‐power laser in vitro. In contrast, stimulation of cancer cells by laser light has not been investigated extensively. The present study attempted to evaluate whether or not human tumor cells could exhibit an increase in colony‐forming capability following low‐watt laser irradiation. LoVo and HT29 (colon carcinoma), MCF7 (breast carcinoma), M14 and JR1 (malignant melanoma) cell lines were irradiated at different doses of light delivered from an argon or an argon‐dye laser. Radiant exposures between 4.2 and 150 kJ/m2 at irradiances ranging from 35 to 500 W/m2 were delivered. Results were mixed. Of the 41 experiments performed, five showed a significant statistical increase in the number of colonies (P< 0.05), whereas three showed a decrease (P < 0.05). Nevertheless, the trend of most data was toward an increase in colony formation, and Wilcoxon's signed‐ranks test suggested that light increases tumor cell culture growth (P < 0.03).
In vitro photosensitization I. Cellular uptake and subcellular localization of mono‐L‐aspartyl chlorin e6, chloro‐aluminum sulfonated phthalocyanine, and photofrin II
Authors: Roberts W. Gregory , Berns Michael W. 
Published: March 2007

AbstractThe mechanisms of cellular uptake, subcellular localization, and cellular retention kinetics of the photosensitizers photofrin II (PfII), mono‐L‐aspartyl chlorin e6 (MACE), and chloro‐aluminum sulfonated phthalocyanine (CASPc) are reported in this paper. Each photosensitizer's cellular uptake mechanism was determined by preferentially inhibiting endocytosis by chilling cells to 2°C, while allowing diffusion across the membrane. Subcellular localization was studied by computer‐enhanced low‐light level video fluorescence microscopy, while flow cytometry was used to determine uptake and retention kinetics. The results indicate that PfII enters the cell primarily by diffusion across the membrane, whereas MACE and CASPc enter the cell through endocytosis.
Acoustic and plasma‐guided laser angioplasty
Authors: Bhatta Krishna M. , Rosen David I. , Dretler Stephen P. 
Published: March 2007

AbstractThe feasibility of using acoustic and plasma‐guided laser (APGL) for angioplasty was studied in vitro. A flashlamp‐pumped tunable dye laser operating at a wavelength of 504 nm (coumarin green) was used as the laser source. Acoustic signals were recorded with a hydrophone, which has a useful frequency response of up to 350 kHz. Plasma optical emissions were transmitted retrograde along the laser fiber and reflected through a beam splitter to an optical detection system consisting of a series of spectral filters (to transmit plasma radiation from 380 nm to 440 nm and block any 504 nm laser light) and a photomultiplier tube.Measurements of the acoustic and the plasma optical signals were obtained from blood, atheromatous plaque, and normal arterial wall. Results of monitoring show that it is possible to know without direct vision whether the laser energy is being discharged in the lumen (blood), on the normal arterial wall, or on the atheromatous plaque. Blood produced strong acoustic signals but no plasma signals; plaque produced strong plasma and strong acoustic signals. Neither plasma nor significant acoustic signals were produced by the normal arterial wall. These distinctions may allow clinical laser ablation of plaque to be performed with fewer complications.
Light distributions in artery tissue: Monte Carlo simulations for finite‐diameter laser beams
Authors: Keijzer Marleen , Jacques Steven L. , Prahl Scott A. , Welch Ashley J. 
Published: March 2007

AbstractFinite‐width light distributions in arterial tissue during Argon laser irradiation (476 nm) are simulated using the Monte Carlo method. Edge effects caused by radial diffusion of the light extend ±1.5 mm inward from the perimeter of a uniform incident beam. For beam diameters exceeding 3 mm the light distribution along the central axis can be described by the one‐dimensional solution for an infinitely wide beam. The overlapping edge effects for beam diameters smaller than 3 mm reduce the penetration of the irradiance in the tissue. The beam profile influences the light distribution significantly. The fluence rates near the surface for a Gaussian beam are two times higher on the central axis and decrease faster radially than for a flat profile. The diverging light from a fiber penetrates tissue in a manner similar to collimated light.
Picosecond optical breakdown: Tissue effects and reduction of collateral damage
Authors: Zysset Beat , Fujimoto James G. , Puliafito Carmen A. , Birngruber Reginald , Deutsch Thomas F. 
Published: March 2007

AbstractThe effects of picosecond laser‐induced optical breakdown on tissue were investigated using high‐intensity 40 ps Nd:YAG laser pulses at 1.06 μm. Tissue damage was evaluated using the corneal endothelium in vitro as a model system. Systematic studies were performed to determine the scaling of the tissue damage and damage range with pulse energy. For suprathreshold lesions, the radius of the damage zone varies as the cube root of the pulse energy, in agreement with simple physical scaling laws. A minimum damage range of less than 100 μm was observed for pulse energies of 8 μJ. Damage morphology was investigated by scanning electron microscopy. Three different damage patterns were observed: cell damage, cell removal, and rupture of Descemet's membrane. Different irradiation geometries were used to study damage mediated by either the shock wave or the cavitation bubble. Comparative studies using 10 ns pulses demonstrated that picosecond pulses yielded a significant reduction in collateral tissue damage.
Laser dentistry: Root canal diagnostic technique based on ultraviolet‐induced fluorescence spectroscopy
Authors: Pini Roberto , Salimbeni Renzo , Vannini Matteo , Cavalieri Stefano , Barone Roberto , Clauser Carlo 
Published: March 2007

AbstractA diagnostic technique to detect residual tissues at different levels of the root canal during an endodontic treatment is presented. The diagnostic system is based on ultraviolet‐induced fluorescence spectroscopy and uses suitable optical fibers for local delivery of excitation light and to collect back fluorescence spectra. Spectra of root canal tissues have been obtained from split teeth by labeling with a fluorescent solution. Residual tissue can be discriminated in respect to healthy dentin because of their different spectral responses: the spectral shape of the first response shows a clear peak at 530 nm because of a selective absorption of the fluorescent dye, whereas for the second response, the spectral curve monotonically increases toward ultraviolet wavelengths with no particular structure. This technique has been tested on unsplit teeth simulating operative conditions. A compact spectroscopic system has been devised that can be easily integrated in an excimer laser system to perform residual tissue detection during laser cleaning of the canals.
Reflectance during pulsed holmium laser irradiation of tissue
Authors: Nishioka Norman S. , Domankevitz Yacov 
Published: March 2007

AbstractAlthough generally ignored in considerations of laser ablation of tissue, reflectance of laser light from tissue during laser‐induced ablation is a potentially important factor in determining ablation efficiency because it determines the amount of laser light coupled into the target. To determine the significance of reflectance changes induced by laser irradiation, we examined the reflectance of liver samples during pulsed holmium laser ablation by placing the target at one focus of an ellipsoidal reflector and a detector at the other focus. The temporal behavior, total reflectance, and effect of multiple pulses were examined. Tissue reflectance as large as 50% was observed during holmium laser irradiation but depended upon laser radiant exposure and number of laser pulses. These measurements suggest that changes in the optical properties of the target during ablation are important and should be considered in detailed modeling of the ablation process.
Should there be a formal mechanical‐optic‐electronic biomedical‐engineering program?
Authors: Goldman Leon 
Published: March 2007

AbstractTo progress in the development of laser medicine and laser surgery, multidisciplinary efforts are required. One important phase in its development is the laser biomedical engineering program being offered following the basic laboratory research. Some of this type of programming is present today, but more development is needed for a formal program offering crossfertilization between engineering and medical uses. Therefore, a formal program is being proposed, which will be reviewed by mixed groups over a period of time. A final recommendation will indicate whether to go ahead with this revision of the program, to wait for further development of the program, or to maintain the status quo. The relationship of technical training for technicians in laser biomedical engineering is also reviewed.
Crosslinking of extracellular matrix proteins: A preliminary report on a possible mechanism of argon laser welding
Authors: Murray Louann W. , Su Lyndon , Kopchok George E. , White Rodney A. 
Published: March 2007

AbstractIn order to elucidate the biochemical mechanism of laser welding of tissues, we have compared protein profiles from argon laser–treated specimens with controls. Extracellular matrix components from untreated and laser‐welded skin and blood vessels were extracted with guanidine hydrochloride and separated by SDS polyacrylamide gel electrophoresis. When compared with matched, untreated tissues, protein electrophoretic profiles from laser‐treated samples showed several changes. In both tissue types, argon laser treatment decreased the concentration of a 235 kd protein that migrates between the alpha and beta chains of type I collagen. Laser‐treated blood vessels showed significantly more low molecular weight protein at the dye front than in control tissue, whereas significantly more high molecular weight protein appeared in laser‐treated skin samples when compared with untreated tissue. These results suggest that the argon laser may either degrade or crosslink proteins in vivo. Laser‐induced protein crosslinks may be the biochemical basis of argon laser welding.
Possibility of choriocapillary occlusion under experimental subretinal hemorrhage by photocoagulation with lasers of different wavelengths
Authors: Miki Tokuhiko , Inoue Kazunori , Obana Akira , Shiraki Kunihiko 
Published: March 2007

AbstractTo clarify the possibility of occluding choroidal neovascularization in subretinal hemorrhage with various laser wavelengths, lesions of experimental subretinal hemorrhage were photocoagulated with argon, dye, and krypton lasers and were examined by light and electron microscopy. Our experimental results revealed that laser photocoagulation with wavelengths longer than 590 nm was effective in occluding the choriocapillaries under a thin subretinal hemorrhage. Complete occlusion of choriocapillaries was accomplished by red dye laser (630 nm) or krypton red laser. The choroidal lesion coagulated by 590 nm dye laser showed more extensive reaction than the other lesions at a posttreatment interval of 7 days. The red dye laser (630 nm) or krypton red laser is recommended for the treatment of neovascular maculopathy under thin subretinal hemorrhage because of less reaction and complete occlusion of the choroidal neovascularization.
Catastrophic injury secondary to the use of coaxial gas‐cooled fibers and artificial sapphire tips for intrauterine surgery: A report of five cases
Authors: Baggish Michael S. , Daniell James F. 
Published: March 2007

AbstractFive women undergoing endometrial ablation with the Nd‐YAG laser developed sudden gas embolism. In each case laser intrauterine contact surgery was carried out utilizing coaxial fibers with (three cases) and without (two cases) artificial sapphire tips but commonly cooled by air or nitrogen. Four of the five women died in a sequence of sudden cardiovascular collapse followed by irreversible cardiac arrest. One woman was critically ill and following prolonged hospitalization survived with neurological deficits.
Helium‐neon laser‐induced respiratory burst of phagocytic cells
Authors: Karu T. I. , Ryabykh T. P. , Fedoseyeva G. E. , Puchkova N. I. 
Published: March 2007

AbstractThe effect of He‐Ne laser radiation (λ = 632.8 nm, I = 6.8 W/m2, irradiation time from 5 to 50 sec) on kinetics of spontaneous and Candida ablicans‐stimulated chemiluminescence of mouse spleen cells was studied. It was found that laser radiation caused significant enhancement (180–250%) both of spontaneous chemiluminescence and Candida‐induced chemiluminescence. The effective dose interval ranges from 100 to 300 J/m2, with a maximum at 200 J/m2. This finding shows that He‐Ne laser irradiation can induce the respiratory burst (generation of reactive oxygen species having bactericidal activity) of phagocytic cells.
Effect of Nd:YAG laser energy on articular cartilage healing in the dog
Authors: Hardie Elizabeth M. , Carlson Cathy S. , Richardson Daniel C. 
Published: March 2007

AbstractThe effect of low dose neodymium:yttrium aluminum garnet (Nd:YAG) laser therapy on cartilage healing was studied. Partial‐ and full‐thickness cartilage defects were surgically created in the femoral condyles of 20 adult dogs. The cartilage defects in one limb of each dog were exposed to 30 J of Nd:YAG laser energy. The dogs were euthanatized 1 week (n = 6), 1 month (n = 7), and 6 months (n = 7) after surgery. Plastic‐embedded, undecalcified histologic sections of each cartilage defect were examined for evidence of cartilage healing. Special stains were used to determine the type of repair tissue present, and morphometric measurements of repair tissue were made. No effect of Nd:YAG laser therapy on cartilage healing was noted.