bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigating the CO2 laser for plantar digital neurectomy in horses
Authors: Montgomery Tom C. , McNaughton Scott D. 
Published: March 2007

AbstractA histological study of plantar digital nerve sections cut with a carbon dioxide laser in horses was conducted. A series of nerve cuts were made with variable power densities to determine the appropriate theoretical level which would yield the most desired tissue effects. Power densities in the lower ranges used appeared to provide tissue effects judged most likely to prevent neuroma formation through increased thermal sealing of the proximal stump at the axon level. Clinical observation and follow‐up of horses subjected to laser neurectomy tend to support the reported concept that the laser is superior to conventional instruments for prevention of painful neuroma in peripheral nerves.
An accurate laser radiometer for determining visible exposure times
Authors: Royston David D. 
Published: March 2007

AbstractA laser light radiometer has been developed for the Electro‐Optics Branch of the Center for Devices and Radiological Health (CDRH). The radiometer measures direct laser radiation emitted in the visible spectrum. Based upon this measurement, the instrument's microprocessor automatically determines at what time duration the exposure to the measured laser radiation would exceed either the class I accessible emission limits of the Federal Performance Standard for laser products or the maximum permissible exposure limits of laser user safety standards. The instrument also features automatic background level compensation, pulse measurement capability, and self‐diagnosis. Measurement of forward surface illumination levels preceding HpD photoradiation therapy is possible.
Effects of varying intensities of laser energy on articular cartilage: A preliminary study
Authors: Schultz Robert J. , Krishnamurthy Shanker , Thelmo William , Rodriguez Jose E. , Harvey Gregory 
Published: March 2007

AbstractThe effects of laser energy on articular cartilage were studied utilizing the neo‐dymium YAG laser. Partial‐thickness cartilage defects were surgically attempted in the femoral condyles of knee joints in guinea pigs. The defects were exposed to laser energy of varying intensities [group I, 25 J (5 W × 5 sec); group II, 75 J (15 W × 5 sec); group III, 125 J (25 W × 5 sec)]. A fourth group was studied, in which the defect was not lased. Animals were killed at weekly intervals from 1 to 6 weeks and the knee joints were subjected to histological analysis. At 5 weeks, the knees exposed to 25 and 75 J demonstrated a reparative process with chondral proliferation. The knees exposed to 125 J demonstrated fibrotic tissue and tissue necrosis that resulted in fibrosis. In the knees not exposed to laser energy, numerous foci of granulation tissue were present at all stages with the end point of healing being one of fibrosis with disorganized patchy cartilage islands.
The CO2 laser as an ideal microsurgical tool
Authors: Ohshiro Toshio 
Published: March 2007

AbstractThe CO2 laser was used as a multipurpose microsurgical tool. It effectively evacuated cysts, vaporized tumors, coagulated fine blood vessels, abraded and flattened scars and rough tissue, and separated the epidermis from the dermis. Focused and defocused modes were applied to various lesions ranging from cysts to freckles. CO2 laser microsurgery differs from previous methods in that extremely fine and controlled therapy can be conducted with minimal damage to surrounding tissues and organs. Theories, techniques, and several case reports are described.
The “chemo‐laser” technique for the treatment of decorative tattoos: A more complete dye‐removal procedure
Authors: Dismukes Don E. 
Published: March 2007

AbstractA technique embodying the use of chemical agents and the argon laser was developed in the 1981–1982 that provides for a more complete removal of tattoo dye with one treatment. The number of visits for the laser treatment to the patient is reduced to two or three treatment sessions, compared to five to eight visits previously required. The area of “chemo‐laser” approximated the normal skin without hypertrophk scar tissue more than the areas of multiple or heavy laser treatment.
Tunable dye laser (577 nm) treatment of port wine stains
Authors: Morelli J.G. , Tan O.T. , Margolis R. , Seki Y. , Boll J. , Carney J.M. , Anderson R.R. , Parrish J.A. , Furumoto H. , Garden J. 
Published: March 2007

AbstractDespite steady improvement in the laser treatment of port wine stains (PWS), hypertrophic scarring remains a serious side‐effect in approximately 10% of patients. The tunable dye laser (577 nm) has been shown to cause selective vascular destruction in normal and PWS skin. We have treated ten patients using a tunable dye laser (577 nm, 300 m̈sec) resulting in clearing of the PWS without any evidence of hypertrophic scarring.Treatment requires no anesthesia or wound care, and there were no postoperative infections.
Bursting pressures of CO2 laser‐welded rabbit lleum
Authors: Sauer Jude S. , Rogers David W. , Raymond Hinshaw J. 
Published: March 2007

AbstractIn this study, the short‐term bond strength of laser‐welded New Zealand white rabbit ileum was examined. Forty‐eight longitudinally oriented 0.5‐cm transmural, scalpel incisions were reanastomosed solely through the use of the CO2 continuous wave laser at low energy levels. Random power levels of 250, 500, 750, or 1,000 mW were delivered to weld sites by either continuous application for 30 seconds or a pulsating application (ie, 0.5 seconds on, 0.5 seconds off) for 60 seconds. This provided 53.6, 107.1, 160.7, and 214.3 J/cm2, respectively. With the aid of a plexiglass clamp and pressure monitored infusion system, each type of weld was tested six times to determine the intraluminal hydrostatic pressure required to burst the welded seam 1 minute after completing the weld. For the welds made with 107.1, 160.7, and 214.3 J/cm2 in both lasing modes, the mean bursting pressure was 40.7 mmHg (SD ± 24.9) with no statistically significant difference in weld strengths at these energy densities. There was also no difference between continuous and pulsating delivery methods. However, the energy density of 53.6 J/cm2 in either method produced a mean bursting pressure significantly lower than those produced by the higher energy densities tested and below the estimated basal ileal intraluminal pressure of approximately 9 mmHg. Since 107.1 J/cm2 energy density caused the minimal gross tissue changes while producing an equally strong bond and since continuous is faster than pulsating, 500 mW of continuous delivery was considered the optimal setting for the CO2 laser welding of rabbit ileum.
Study of the in vivo and in vitro photosensitizing capabilities of uroporphyrin I compared to photofrin II
Authors: Stuart Nelson J. , Sun Chung‐Ho C. , Berns Michael W. 
Published: March 2007

AbstractThe in vivo biological activity of uroporphyrin I has been studied by determining the amount of necrosis produced in murine tumors exposed to various total doses of light at 615 nm. Similarly, the in vitro photosensitizing activity of uroporphyrin I was examined by measuring the percentage of cells killed in a cell culture system.Light doses used were 25–400 J/cm2. Mice that received uroporphyrin I at 40 mg/kg had only minimal superficial necrosis upon histological examination at doses of 400 J/cm2 (615 nm). Those tumors that received 300 J/cm2 or less showed no histological evidence of necrosis. Mice that received hematoporphyrin derivative (Photofrin II) at 10 mg/kg were completely necrotic at total doses of 100 J/cm2 (630 nm). PTK2 epithelial cells incubated with uroporphyrin I at either 40 μg/ml or 80 μ/ml and 10 J/cm2 (615 nm) showed no apparent damage and had 100% cell survival. By contrast, those cells treated with hematoporphyrin derivative (Photofrin II) at 25 μ/ml and 10 J/cm2 (630 nm) exhibited 100% cell kill.It is concluded that uroporphyrin I is a poor photosensitizer in both in vivo and in vitro systems compared to hematoporphyrin derivative (Photofrin II).
Cylindrical irradiator fiber tip for photodynamic therapy
Authors: Arnfield M. , Gonzalez S. , Mcphee M. , Tulip J. , Lea P. 
Published: March 2007

AbstractIn photodynamic therapy (PDT) the uniform distribution of intratumor or externally applied light is desirable but often difficult to achieve. An optical fiber tip producing cylindrical or lateral light emission can facilitate the application of laser energy by direct implantation of the tip into solid tumors or within tubular cavities of the body such as the bronchus or esophagus. A procedure is described for fabricating such a fiber tip, the main component of which is a hollow glass cylinder containing a light‐scattering material. Light distributions emitted from the tip in air are documented. Useful properties of the tip include good light distribution, durability, heat resistance, and simplicity of construction.
Contact neodymium: YAG laser surgery in gastroenterology: A preliminary report
Authors: Joffe Stephen N. 
Published: March 2007

AbstractFifty‐four patients have been successfully endoscopically treated without complications using contact neodymium:YAG laser probes (endoprobes) for tumors and bleeding and, during open surgery (laser scalpel), for liver and pancreatic resections. The contact probes made from a synthetic sapphire crystal with its optical properties, geometric design, and thermal conductivity have proven to be more effective than the current conventional noncontact method of delivering laser energy through a quartz fiber. Advantages include greater precision, sterilizability, avoidance of the tip melting, and a requirement for lower neodymium: YAG laser energy with reduced tissue damage. The configuration of the probes allows coagulation, cutting, or vaporization, depending on the clinical condition being treated.
Urologic dosimetry studies with the Nd: YAG and CO2 lasers: Bladder and kidney
Authors: Stein Barry S. 
Published: March 2007

AbstractDose recommendations for the use of the Nd: YAG and CO2 lasers have been accepted with little laboratory analysis. We have examined both endoscopic and open applications in the bladder and open applications on the kidney with the lasers over a variety of power and pulse duration settings. In addition, we have studied the effect of varying the temperature of the tissue and irrigation solution on the depth of penetration.We found that with the Nd: YAG laser, the maximum depth of penetration in our animal model was only 2.62 mm in the bladder. This occurred during an endoscopic treatment with settings of 50 W at 4 seconds with irrigation solution of 25°C. The depth of penetration using current recommendations of 40 W for 2 seconds was<1 mm at all temperatures. Room temperature irrigation solution may be the ideal compromise, but higher‐power long‐pulse durations or repeated treatments to the same area may be necessary to achieve penetrations of 3–5 mm. In open applications on bladder and kidney, the maximum depth of penetration in our animal model was 2.75 mm, which was found during a treatment with settings of 60 W at 4 seconds with the kidney parenchyma at 25°C.Using the CO2 laser on open applications of bladder strips, we obtained a maximum depth of penetration of 1.75 mm at 30 W of power for 1/2 second at 85°C tissue temperature. Unfortunately, penetration by the CO2 laser is accompanied by vaporization of tissue, leaving a large crater. Minimal injury exists beyond this area. In the kidney, we obtained a maximum depth of penetration of 1.75 mm at 30 W of power at 25°C and 20 W of power at 2°C each for 1/2 second.
Optical dosimetry in photodynamic therapy
Authors: Grossweiner Leonard I. 
Published: March 2007

AbstractThe diffusion approximation for the radiant flux distribution in a tissue layer has been applied to optical dosimetry in photodynamic therapy of malignant tumors. The model assumes that tumor eradication requires a minimum absorbed energy by the localized photosensitizer, taken as 0.19 J/cm3 for hematoporphyrin derivative (HPD) at 630 run. The analysis leads to the required incident irradiance for front surface illumination as a function of the tumor depth, the optical penetration depth of the tumor, and the concentration of localized sensitizer. The effect of HPD photobleaching on the required light dose and drug dose levels is considered. The results are given in tabular form for typical clinical applications.
Milliwatt carbon dioxide laser and hepatic surgery in mice: Surgical technique and pathology
Authors: Rao Leela N. , Ammirati Mario , Murthy Satya M. , Goldschmidt Robert A. , Ciric Ivan S. , Scanlon Edward F. 
Published: March 2007

AbstractThe milliwatt carbon dioxide laser was used to induce focal lesions and to perform wedge resections in the livers of 75 strain A mice. The procedures were feasible and well tolerated by the mice, with only one postoperative death in the wedge resection group in an early experiment. The hepatic lesions produced by the laser were characterized histologically by an inner area of vaporization, an intermediate area of coagulation necrosis, and an outer rim of cells with variable damage. The lesions healed by fibroblastic proliferation and scar formation with no hepatocytic contribution. The small vessel and bile ductule sealing effect of CO2 laser, together with the sound healing of laser‐induced wounds, highlights the usefulness of this modality in liver surgery in general, and suggests its particular application in the treatment of liver trauma and a variety of hepatic focal lesions, neoplastic or otherwise.
Modeling optical and thermal distributions in tissue during laser irradiation
Authors: Jacques Steven L. , Prahl Scott A. 
Published: March 2007

AbstractThe propagation of light energy in tissues is an important problem in phototherapy, especially with the increased use of lasers as light sources. Often a slight difference in delivered energy separates a useless, efficacious, or disastrous treatment. Methods are presented for experimental characterization of the optical properties of a tissue and computational prediction of the distribution of light energy within a tissue. A standard integrating sphere spectrophototneter measured the total transmission, Tt, total reflectance, Rt, and the on‐axis transmission, Ta, for incident collimated light that propagated through the dermis of albino mouse skin, over the visible spectrum. The diffusion approximation solution to the one‐dimensional (1‐D) optical transport equation computed the expected Tt, and Rt, for different combinations of absorbance, k, scattering, s, and anisotropy, g, and by iterative comparison of the measured and computed Tt, and Rt, values converged to the intrinsic tissue parameters. For example, mouse dermis presented optical parameters of 2.8 cm−1, 239 cm−1, and 0.74 for k,s, and g, respectively, at 488 nm wavelength. These values were used in the model to simulate the optical propagation of the 488‐nm line of an argon laser through mouse skin in vivo. A 1‐D Green's function thermal diffusion model computed the temperature distribution within the tissue at different times during laser irradiation. In vitro experiments showed that the threshold temperature range for coagulation was 60°–70° C, and the kinetics were first order, with a temperature‐dependent rate constant that obeyed an Arrhenius relation (molar entropy 276 cal/mol‐°K, molar enthalpy 102 kcal/mol). The model simulation agreed with the corresponding in vivo experiment that a 2‐s pulse at 55 W/cm2 irradiance will achieve coagulation of the skin.
Ultraviolet laser ablation of skin: Healing studies and a thermal model
Authors: Lane R. J. , Wynne J. J. , Geronemus R. G. 
Published: March 2007

AbstractWe have followed the course of healing of incisions made with the krypton‐fluoride excimer laser. Incisions were made in guinea pig skin, in vivo, under identical conditions of irradiation. The progressive healing of these incisions was followed over the course of 3 weeks. We noted excellent healing with re‐epithelialization, and the re‐formation of collagen fibers with minimal fibrosis. We present a simple thermal model for ablation of tissue by a short pulse of strongly absorbed laser radiation.
The influence of mechanical forces and flow mechanisms on vessel occlusion
Authors: Fankhauser F. , Kwasniewska S. , Bebie H. 
Published: March 2007

AbstractThe exact mechanism of irradiation‐induced occlusion of normal or abnormal retinal vessels is still to a large extent obscure. Blood flow acts as a powerful heat dissipation mechanism. Therefore, a procedure which reduces flow velocity as rapidly as possible after the beginning of irradiation may work with higher efficiency. A theory based on a simplified assumption states that vessel narrowing techniques, which involve only a short length of the vessel to be occluded by a small focus diameter irradiation beam, are less efficient in bringing blood velocity down than a procedure which narrows the vessel over a greater length by a larger focus diameter irradiation beam.The thrombus building up over a greater length of the affected part of the vessel may also better resist the pressure head building up after thrombogenesis is complete because friction between thrombus and vessel wall is larger, and occlusion may, therefore, be more durable. One has to assess, therefore, whether a small‐spot technique, which is presumed to be less efficient and may need repetitions, is in fact less innocuous for the surrounding retina—as is generally assumed—than a technique using a larger beam diameter, which, because it is more efficient, may need fewer or even no repetitions.
Mechanisms of healing in the injured lung treated with the Nd‐YAG laser
Authors: Cole Peter H. , Wolfe Walter G. 
Published: March 2007

AbstractAn experimental study was done to evaluate the pattern of healing after sealing an incision in the pulmonary parenchyma with the Nd‐YAG laser. Gross and histologic examinations of healing were compared with those of lung cauterized or sutured with chromic catgut. The results indicate that the use of the Nd‐YAG laser to seal small vessels and air leaks has distinct advantages over cautery or suture closure of incisions in pulmonary tissue.
Safety of high‐energy neodymium: YAG laser pulses in YAG sclerostomy
Authors: March Wayne F. , Gherezghiher Tseggai , Shaver Robert P. , Koss Michael C. , Nordquist Robert E. 
Published: March 2007

AbstractYAG sclerostomy was performed in 15 eyes of nine cynomolgus monkeys. Individual pulse energies ranged between 10 and 135 millijoules. Total pulse energy ranged between 2,000 and 36,000 millijoules in order to test the extreme range of energy that might be required. Both acute effects and chronic effects were studied in the corneal endothelium, the lens capsule, the iris, the ciliary body, the retina, and the sclera. Techniques included flat preparations of the corneal endothelium, paraffin sections for light microscopy, and scanning and transmission electron microscopy. Our conclusion is that individual pulse energies of up to 135 millijoules with a total of up to 36 joules of energy are safe in monkey eyes when performing YAG sclerostomy.
Tissue precooling for thermochemical damage reduction during laser surgery
Authors: Laufer G. , Joachims H. Z. , Mordechovitz D. , Armon E. 
Published: March 2007

AbstractThis report describes a preliminary investigation of the possibility of reducing the thermal damage induced by lasers in the course of laser surgery. Skin incisions made by CO2 laser beams – with and without precooling – were evaluated and compared with scalpel cuts. Full thickness cuts were carried out on the flanks of adult cats. Precooling was achieved by spraying chlorethyl just before the laser application. Both the precooled and the regular laser incisions were bloodless. The precooled cuts however produced considerably less amount of charring and therefore smoother and cleaner cut edge.The incisions were sutured and the cats were kept under supervision. Upon inspection four weeks later all incisions were completely healed. No skin thickening or keloid were present. The scar produced by the regular laser technique was much more pronounced and wide relative both to the scars of the precooled or the scalpel cuts which were almost alike.
Study of three laser systems for treatment of superficial varicosities of the lower extremity
Authors: Apfelberg David B. , Smith Teruko , Maser Morton R. , Lash Harvey , White David N. 
Published: March 2007

AbstractThree separate laser modalities were investigated in the treatment of superficial varicosities/telangiectasias of the lower extremities. Sixteen patients were treated and followed for 12 months. The superpulse CO2, the pulsed focally specific CO2, and the Nd:YAG laser transmitted through a diffusing sapphire tip were able to produce cosmetically satisfactory permanent obliteration of vessels after a 12‐months follow‐up interval. These results were a significant improvement over six‐months results indicating a long fading time for laser treatment of leg veins.
Large vessel sealing with the argon laser
Authors: White Rodney A. , Kopchok George , Donayre Carlos , Lyons Richard , White Geoffrey , Klein Stanley R , Pizzurro Damon , Abergel R. Patrick , Dwyer Richard M. , Uitto Jouni 
Published: March 2007

AbstractThis study compared the histology, biochemistry, and tensile strength of laser‐welded and sutured canine venotomies, arteriotomies, and arteriovenous fistulas. Twelve animals had bilateral femoral vessels studied, with one repair (control) closed with interrupted 6‐0 polypropylene sutures, and the contralateral repair (experimental) welded with the argon laser. Specimens were examined at weekly intervals from 1 to 4 weeks (four animals for each type of repair), and were evaluated histologically by hematoxylin and eosin, elastin, and trichrome stains; biochemically by the formation of [3H]hydroxyproline as an index of collagen synthesis; and mechanically by tensile strength determinations. At removal, all experimental closures were patent without hematomas, aneurysms, or luminal dilatation. Histologic and biochemical examination and tensile strength determinations suggest that laser welding may be an alternative to sutures for repair of large‐diameter venotomies, arteriotomies, and arteriovenous fistulas, as healing is comparable to that seen with suture repairs up to 4 weeks postoperatively.
Ultrastructural study of arterial wall repair after argon laser micro‐anastomosis
Authors: Godlewski G. , Rouy S. , Dauzat M. 
Published: March 2007

AbstractA carotid end‐to‐end anastomosis was performed in 50 Wistar rats by means of a Coherent 900 argon laser. The vessel sealing was obtained with laser shots (average 19) or 300 mW power and 5‐second duration, the beam being focused in a spot of 150 μm diameter (1,700 W/cm2). From day 0 to day 120, 25 specimens underwent semithin and electron microscopic examinations. The results showed the immediate sealing effect of the argon laser owing to protein denaturation and collagen fusion of the media and adventitia 100 μm in width. Re‐endothelialization of the anastomotic line began by day 3, while myofibroblast proliferation was observed in the media by day 10. By day 20 media scar was still occupied by numerous myofibroblasts and surrounded by abundant collagen and elastic fibres. At long term the endothelial repair was complete and the anastomotic strength was assured by medial collagenous network.