bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of force on ablation depth for a XeCl excimer laser beam delivered by an optical fiber in contact with arterial tissue under saline
Authors: Gijsbers Geert H. M. , van den Broecke Duco G. , Sprangers René L. H. , van Gemert Martin J. C. 
Published: March 2007

AbstractThe effect of force applied to a 430 üm single fiber, delivering 60 pulses of 308 nm XeC1 laser radiation at 20 Hz, on the ablation depth in porcine aortic tissue under saline has been investigated. Energy densities of 8,15,25, 28, 31, 37, and 45 mJ/mm2 were used. Force was applied by adding weights from 0 to 10 grams to the fiber. The fiber penetration was monitored by means of a position transducer. At 0 grams, the ablation depth increased linearly with incident energy density, but the fiber did not penetrate the tissue; with any weight added, the fiber penetrated the tissue at energy densities above 15 mJ/mm2. The fiber did not penetrate during the first several pulses, possibly due to gas trapped under the fiber. After these first pulses, a smooth linear advancement of the fiber began, which lasted until the pulse train stopped. The ablation depth increased with increasing energy densities and weights. This effect was largest above 25 mJ/mm2 where the ablation efficiencies (unit mm3 /J), with weights added to the fiber, were substantially larger than values found in 308 nm ablation experiments described in the literature, which were conducted with either a focused laser beam or a fiber without additional force. The results imply that in 308 nm excimer laser angioplasty, force must be applied to the beam delivery catheter for efficient recanalization, and that experiments performed with a focused beam or without actual penetration of the fiber do not represent the situation encountered in excimer laser angioplasty. © 1992 Wiley‐Liss, Inc.
Laser reflections from surgical instruments
Authors: Wood Rodney L. , Sliney David H. , Basye Robert A. 
Published: March 2007

AbstractThe potential hazards to the eye and skin from accidental exposures caused by reflected laser beams from surgical instruments has long been of concern to operating room staff members. Reflectance values for argon neodymium:YAG and CO2 laser wavelengths were measured from 29 reference surfaces used on surgical instruments. From these measurements, nominal hazard zones could be determined for typical reflection hazards. © 1992 Wiley‐Liss, Inc.
Absence of rhodamine 123‐photochemotoxicity in human tumor xenografts
Authors: Ris Hans‐Beat , Altermatt Hans Jörg , Schaffner Thomas , Lim Chang Kee , Potter William R. , Althaus Ulrich 
Published: March 2007

AbstractRhodamine 123 (R123)‐photochemotoxicity was assessed in BALB/c nude mice bearing a xenografted human squamous cell carcinoma at various power densities and wavelengths and a given incident fluence of 150 Joules/cm2. One hour before light delivery, 1 mg R123/kg was injected i.p. in 20 animals. Surface irradiance was performed on the tumor and an equal size hind leg area of 40 animals. Three groups of 10 animals were treated at 514.5 nm and 0.1 W/cm2, 1 W/cm2, and 30 W/cm2, and one at 488 nm and 30 W/cm2. In each group, five animals received R123. The R123 concentration was measured in the tumor (0.023 ± 0.007 μg/g) and tumor‐free tissue (0.023 ± 0.008 μg/g) in three additional animals by high performance liquid chromatography 1 hour after R123‐administration. Histologic assessment 72 hours after light delivery revealed no tissue damage at nonthermal power densities, either in the tumor or in the tumor‐free tissue, irrespective of R123‐administration. At 30 W/cm2, neither in the tumor nor in tumor‐free tissues was there any significant difference in the depth of necrosis, irrespective of R123‐administration and the wavelength applied. Our results question the validity of R123 as a photosensitizer, at least in this rodent tumor model. © 1993 Wiley‐Liss, Inc.
Low power laser irradiation alters the rate of regeneration of the rat facial nerve
Authors: Anders Juanita J. , Borke Rosemary C. , Woolery Sara K. , van de Merwe Willem P. 
Published: March 2007

AbstractLow power laser irradiation has been reported to cause biological effects due to the photochemical and/or photophysical action of the radiation. This study determined quantitatively if transcu‐taneous low power laser irradiation can affect the regeneration of the rat facial nerve. The facial nerve was crushed unilaterally in anesthetized rats and transcutaneously irradiated daily with a laser beam directed at the area of the crush injury. Laser treatment began on the day of the crush injury and was continued daily for 7, 8, or 9 days. Preliminary experiments determined the most effective wavelength, laser power, length of irradiation, and treatment schedule. The wavelengths examined were 361, 457, 514, 633, 720, and 1064. The laser powers and lengths of irradiation examined ranged from 8.5 to 40 mW and 13 to 120 min. Irradiation treatment was done daily, on alternating days and on the first 4 days postcrush. The most effective laser parameters for the low power treatment included daily irradiation with a helium‐neon (HeNe) or argon pumped tunable dye laser a wavelength of 633 nm, with a power of 8.5 mW for 90 minutes (45.9 J, 162.4 J/cm2). The number of horseradish peroxidase (HRP) labeled neurons in the facial motor nucleus was used as an assay of the degree of regeneration. In rats in which the facial nerve was crushed but not irradiated, the average number of HRP labeled neurons in the facial nucleus was 22 on day 7 postcrush, 54 on day 8, 116 on day 9, and 1,149 on day 10. After HeNe or argon pumped tunable dye laser irradiation, the average number of HRP‐labeled neurons increased to 34 on day 7 postcrush, 148 on day 8, and 1,725 on day 9. There was a statistically significant difference between the control and irradiated rats on day 9 post‐crush (P < 0.01). These data indicate that transcutaneous low power irradiation with the lasers and parameters involved in this study increased the rate of regeneration of rat facial nerve following crush injury. © 1993 Wiley‐Liss, Inc.
XeCl laser ablation of atherosclerotic aorta: Luminescence spectroscopy of ablation products
Authors: Oraevsky Alexander A. , Jacques Steven L. , Pettit George H. , Tittel Frank K. , Henry Philip D. 
Published: March 2007

AbstractXeCl laser ablation of atherosclerotic aorta tissue was investigated. Luminescence spectra of ablation products were measured for soft and hard arterial tissues. A pronounced difference observed between plume luminescence for various plaques and normal vessel wall correlates with the chemical composition of the tissue. The mechanism of plume luminescence appeared to be thermochemical excitation of ablation products (particles, atoms, molecules, etc.) in the air. The process of soft tissue ablation was delayed with respect to the exciting laser pulse at relatively low laser fluences close to the ablation threshold. The kinetics of the ablation process as a function of laser‐pulse energy fluence is reported. The data indicate that tissue ejection mechanism, which involves vapor bubbles formation, expansion and explosion, is suitable for the description of the XeCl excimer laser ablation of soft tissues. © 1993 Wiley‐Liss, Inc.
Injury and adhesion formation following ovarian wedge resection with different thermal surgical modalities
Authors: Bhatta N. , Isaacson Keith , Flotte Thomas , Schiff Isaac , Anderson R. Rox 
Published: March 2007

AbstractThe purpose of this study is to determine the role of bleeding, acute thermal damage, and charring in adhesion formation. Postoperative adhesions were compared following ovarian wedge resection in 48 rabbits using different lasers, electrosurgery, and scalpel. Twelve ovaries were sectioned per modality, in randomized pairs. Acute thermal injury as assessed by histology, bleeding, and charring differed amonge the modalities used. Adhesions were assessed 4 weeks later, by an investigator completely blinded of the treatment protocol. The adhesion scores were 11.6 ± 8.0 with pulsed Er:YAG laser; 11.9 ± 7.5 with scalpel; 8.3 ± 9.3 with electrocautery; 6.7 ± 8.8 with a continuous (c.w.) Nd:YAG laser; 5.3 ± 4.8 with c.w. CO2 laser; 3.1 ± 2.7 with pulsed CO2 laser; 1.7 ± 1.8 with pulsed Ho:YAG laser; and 0.8 ± 1.5 in the control (no resection) group. Ho:YAG, Nd:YAG, and electrocautery were completely hemostatic. Bleeding was minimal with the CO2 lasers. Er:YAG and scalpel caused maximum bleeding, requiring hemostatic measures to prevent exanguination. Charring occurred with electrocautery, CO2 laser, and Nd:YAG laser. Bleeding and charring correlated with adhesion formation, but the histological depth of thermal damage did not. The Ho:YAG laser is a hemostatic, fiber‐optic compatible laser causing significantly fewer adhesions (P<0.04) than scalpel, electrocautery, Nd:YAG, Er:YAG, and c.w. CO2 lasers. Clinical use of the Ho:YAG laser, and the role of carbonization in promoting adhesions, deserve further study. © 1993 Wiley‐Liss, Inc.
Alteration of argon laser–induced scars by the pulsed dye laser
Authors: Alster Tina S. , Kurban Amal K. , Grove Gary L. , Grove Mary J. , Tan Oon Tian 
Published: March 2007

AbstractTen patients with portwine stains (PWS) with test sites previously exposed to an argon laser were evaluated and subsequently treated with five pulsed dye (585 nm) laser treatments over a 10 month period. Clinical assessments, skin surface texture analyses using optical profilometry, and light microscopic histological evaluations were performed prior to commencement and at the end of the study in all ten patients. A change in the skin texture with return of skin markings approximating those of normal skin measured by optical profilometry was observed in the argon treated PWS skin following pulsed dye laser treatments. © 1993 Wiley‐Liss, Inc.
Studies of acoustical and shock waves in the pulsed laser ablation of biotissue
Authors: Esenaliev Rinat O. , Oraevsky Alexander A. , Letokhov Vladilen S. , Karabutov Alexander A. , Malinsky Taras V. 
Published: March 2007

AbstractQuantitative studies are conducted into the absolute pressure values of the acoustical and shock waves generated and propagating in a biotissue under pulsed (τP = 50 ns) UV (λ = 308 nm) laser irradiation (below and above the ablation threshold). Powerful (several hundreds of bars in pressure) high‐frequency (f ≃ 107 Hz) acoustic compression and rarefaction pulses are found to be generated in the biotissue. The amplitudes and profiles of the acoustic pulses developing in atherosclerotic human aorta tissues and an aqueous CuCl2 solution under laser irradiation are investigated as a function of the laser pulse energy fluence. The results obtained point to the absence of the cold spallation of the objects of study by rarefaction waves. Based on experimental data, the rise rates, pressure gradients, and propagation velocities of shock waves in the biotissue are calculated. The experimental data are found to agree well with the theoretical estimates. © 1993 Wiley‐Liss, Inc.
Argon laser oral safety parameters for teeth
Authors: Powell G. Lynn , Morton Thomas H. , Whisenant Brian K. 
Published: March 2007

AbstractArgon lasers have been reported to prevent or reduce demineralization of enamel in extracted teeth and to polymerize dental composites (using 25–100 J/cm2). Prior to clinical trials on caries prevention and curing composites, safety parameters for intraoral use of the argon laser need to be established. This study was conducted to determine the enamel damage, pulp temperature changes, and associated pulpal tissue damage following irradiation at various argon laser energy levels using 1.6–6.0 watts, ∼ 1 and 2 mm diameter beam for 0.2–5.0 seconds. To evaluate pulpal damage, selected dogs' teeth were irradiated in vivo, extracted 7 days postlasing, fixed, decalcified, sectioned, stained, and read for pulpal damage. Pulp temperature and enamel damage tests utilized extracted dog and human teeth. Temperature probes were inserted in the pulp chambers and temperature changes recorded as enamel surface was lased. Enamel surface damage was evaluated by visual and microscope examination. Results showed that histologic pulpal damage occurred at > 600 J/cm2. Temperature changes were < 6° F in human teeth with ∼ 900 J/cm2. No enamel damage was observed at these energy densities. At energy densities needed for proposed uses, no apparent damage would be expected to pulp or enamel. © 1993 Wiley‐Liss, Inc.
Optical modelling of light distributions in skin tissue following laser irradiation
Authors: Miller Iain D. , Veitch A. Roy 
Published: March 2007

AbstractA Monte‐Carlo method is used to compute light distributions in a multilayer skin model for variable width finite beams. By means of a 4‐layer skin model in which blood may be represented as a discrete layer, vascular lesions such as portwine stains may be studied. Light distributions and thermal profiles are simulated, representing the irradiation of a portwine stain using 577 nm and 585 nm wavelengths. Damage thresholds at 585 nm are found to substantially exceed those predicted at 577 nm, although the nature of the damage differs at the two wavelengths. Variations due to beam width are found to be unimportant if the diameter exceeds 1 mm. The predictions are compared with clinical results, and a novel 5‐layer approach based on new optical parameters is adopted to account for discrepancies in epidermal temperature. © 1993 Wiley‐Liss, Inc.
Effect of irradiation by semiconductor laser on responses evoked in trigeminal caudal neurons by tooth pulp stimulation
Authors: Wakabayashi Hajime , Hamba Michiko , Matsumoto Koukichi , Tachibana Hitoshi 
Published: March 2007

AbstractThe effect of irradiation with a gallium‐aluminum‐arsenide semiconductor laser on responses evoked in trigeminal subnucleus caudal neurons by tooth pulp stimulation was investigated electrophysiologically in Wistar rats anesthetized with urethane plus α‐chloralose. The pulp of lower incisor was electrically stimulated and the evoked action potentials were extracellularly recorded in the ipsilateral caudal neurons. The laser beam was applied on the cervical surface of the stimulated incisor. The rate of firing discharges and the numbers of spikes evoked in the caudal neurons were compared before and after laser irradiation. Laser irradiation suppressed the late discharges in the response of the caudal neurons which were evoked by excitatory inputs from C‐fiber afferents, but did not suppress the early discharges evoked by inputs from Aδ‐fiber afferents. This indicates that low power laser irradiation (semiconductor laser: 830 nm, 350 mW, CW, through the tooth structures, for 120 s) inhibited the excitation of unmyelinated fibers of the pulp without affecting fine myelinated fibers. These results suggest that low power laser irradiation has a suppressive effect on injured tissue by blocking the depolarization of C‐fiber afferents. © 1993 Wiley‐Liss, Inc.
Cell vitality in cartilage tissue culture following excimer laser radiation: An in vitro examination
Authors: Fischer R. , Krebs R. , Scharf H.‐P. 
Published: March 2007

AbstractExcimer laser is used for cartilage debridement, although the resulting cell damage is yet unclear. For examination of cartilage survival after treatment, we used short‐term tissue cultures of human joint cartilage. Specimens were treated with a XeCl‐Excimer laser using different laser parameters, pulse energies, and repetition rates. Following treatment, discs were cultured for 8 days prior to examination. In contrast to the 20 μm damage zone as instant visible effect in histomorphologic examinations, we found a 0.3 mm zone in which ∼ 50% of cartilage cells had morphological signs of damage on light microscopic examinations. Autoradiography revealed that cartilage cells in an 0.5–0.7 mm area surrounding the laser craters had no collagen synthesis. This examination indicates that cell damage of excimer laser is higher than expected from prior studies. © 1993 Wiley‐Liss, Inc.
Tolerance of small bowel anastomoses in rabbits to photodynamic therapy with dihematoporphyrin ethers and 630 nm red light
Authors: Delaney Thomas F. , Sindelar William F. , Thomas Gunter F. , Deluca Anne M. , Taubenberger Jeffery K. 
Published: March 2007

AbstractPhotodynamic therapy (PDT) is being evaluated in experimental clinical trials in patients with peritoneal malignancies. Some patients require partial small bowel resection with re‐anastomosis prior to PDT because of bulky tumor or focal involvement of the small bowel by tumor. To assess the safety of PDT in this setting, the tolerance of small bowel anastomoses in New Zealand white rabbits to PDT with dihematoporphyrin ethers (DHE) and 630 nm light was studied. With conventional DHE doses of 1.5–2.5 mg/kg given 24 hours prior to surgery and light doses of 0–20 J/cm2 of 630 nm light, no adverse effects were seen on the healing of small bowel anastomoses. Higher photosensitizer doses of 10 mg/kg and 20 mg/kg in conjunction with 20 J/cm2, however, induced failure and breakdown of fresh anastomoses in 2/3 and 4/4 animals, respectively. © 1993 Wiley‐Liss, Inc.
Formation of pressure waves during in vitro excimer laser irradiation in whole blood and the effect of dilution with contrast media and saline
Authors: Baumbach Andreas , Haase Karl K. , Rose Carsten , Oberhoff Martin , Hanke Hartmut , Karsch Karl R. 
Published: March 2007

AbstractPressure waves during excimer laser ablation of vascular tissue may be responsible for complications of coronary excimer laser angioplasty. In this experimental study, pressure waves were measured during excimer laser irradiation in blood and contrast media using a polyvinilidenefluoride hydrophone. At a distance of 4 mm lateral to the tip of a 1.7 mm multifiber laser catheter, excimer laser irradiation in blood resulted in a linear increase of peak pressures from 1,365 ± 165 kPa at 30 mJ/mm2 to 2,866 ± 404 kPa at 60 mJ/mm2. In contrast media, peak pressure increased from 3,172 ± 573 kPa (30 mJ/mm2) to 5,763 ± 467 kPa (60 mJ/mm2). Contrast media and saline were added to blood. At a concentration of 60% contrast in blood, a 3.4 fold increase of peak pressures was documented as compared to pure blood. Further increase of the concentration did not result in higher pressure waves. Concentrations of saline in blood of 90% and 96% reduced the peak pressures by 16% and >50%, respectively, as compared to pure blood. © 1994 Wiley‐Liss, Inc.
Acute biological response to laser balloon angioplasty in the atherosclerotic rabbit
Authors: Alexopouios Dimitrios , Sanborn Timothy A. , Marmur Jonathan D. , Badimon Juan J. , Badimon Una , Dische Renate , Fuster Valentin 
Published: March 2007

AbstractLaser balloon angioplasty with Nd:YAG energy has been proposed as a method to seal intimal dissection and prevent elastic recoil after balloon angioplasty. To better define the vessel response to laser balloon angioplasty, its effects on luminal diameter, Indium‐111 labelled platelet deposition, and histology were studied in 10 atherosclerotic rabbits. Balloon angioplasty was performed in both iliac arteries and was followed by laser balloon angioplasty in only one iliac artery. The nonlased artery served as a control. Single (15–35 W for 20 sec) or repetitive laser pulses (12–25 W for 20 sec × 3) were used. Platelet deposition was quantified 2 hr after the intervention. Lumen diameter (mm) increased following balloon angioplasty from 0.99 ± 0.47 (mean ± SD) to 1.92 ± 0.43 and 0.89 ± 0.46 to 1.99 ± 0.57 in the balloon and laser‐treated arteries, respectively (P < 0.001 for both groups for comparisons to baseline, P = NS for between groups comparison). Laser balloon angioplasty resulted in a further increase in luminal diameter to 2.42 ± 0.53 (P < 0.02) when compared to the post balloon angioplasty diameter. Platelet deposition (106/cm vessel) was higher following laser balloon angioplasty (26.9, 10.2–189; median range) than after balloon angioplasty (10.6, 3.4–30), P < 0.001. Histologic evidence of laser “sealing” was present in only one artery. Thus although laser balloon angioplasty results in an improved lumen diameter, it is accompanied by increased platelet deposition. In the atherosclerotic rabbit model, abolition of vascular recoil rather than “sealing” seems to be the most important advantage of laser balloon angioplasty over conventional balloon angioplasty. © 1994 Wiley‐Liss, Inc.
Toxicity of photodynamic therapy with photofrin in the normal rat brain
Authors: Ji Ying , Powers Stephen K. , Brown J. Tony , Walstad Diana , Maliner Lloyd 
Published: March 2007

AbstractThe widespread acceptance of photodynamic therapy (PDT), a potential adjuvant brain tumor therapy under clinical evaluation since 1980, has been partially restrained by its potential toxicity toward normal brain tissue. This study examined PDT‐produced injury of normal rat brain as a function of photosensitizer dose. Brain injury was characterized by correlating measurements of the area of cerebral edema using T2‐weighted magnetic resonance images, measurement of brain water content at the lesion site, microscopic examination of histological sections through the PDT lesion, and by evaluation of the area of blood brain barrier (BBB) disruption using computerized morphometric analysis of the region of Evans blue (EB) dye‐labelled albumin extravasation. Monochromatic red light (630 nm) was delivered intracere‐brally using a 5‐mm‐long cylindrical, diffusion‐tip optical fiber at a constant energy dose of 15 joules.A Photofrin dose of 2 mg/kg of body weight produced a transient breakdown in the blood brain barrier around the site of the implanted optical fiber demonstrated by magnetic resonance imaging (MRI), extravasation of EB dye and pallor on hematoxylin and eosin‐stained microscopic tissue sections. A much larger area of BBB disruption was seen at a dose of 4 mg/kg of Photofrin, and this drug dose resulted in significant permanent brain injury. In this model, a Photofrin dose of 4 mg/kg body weight is not tolerated by the normal brain. © 1994 Wiley‐Liss, Inc.
Thermal side effects of fiber‐guided XeCl excimer laser drilling of cartilage
Authors: Fischer R. , Hibst R. , Schröder D. , Puhl W. , Steiner R. 
Published: March 2007

AbstractWe examined thermal effects during ablation of human joint cartilage using two XeCl excimer lasers with pulse durations of ∼ 20 ns and 60 ns. An increase in radiant exposure or repetition rate caused a rise in tissue temperature up to 82°C at a 100‐ μm distance. With increasing distance from the crater edge, the temperature dropped exponentially. Radiant exposures higher than 1.8 J/cm2 and repetition rates above 20 Hz lead to a formation of hot gaseous products escaping from the laser crater. When os‐teoarthritic cartilage is irradiated, these gases spread inside the tissue causing a temperature rise of > 50°C at a distance of 1 mm from the crater edge. In the contact mode, we found a linear rise of ablation rate with increasing repetition rate both in air or saline. But ablation rates in saline were only half the rates achieved in air. Both phenomenons can be explained by additional thermal effects of excimer lasers working in the range of higher repetition rates and pulse energies. © 1994 Wiley‐Liss, Inc.