bluuebunny/crossref_metadata_2025_split huggingface dataset:
Role of immersion refractometry for investigating laser‐induced effects in cells
Authors: Tribble Jerri , Kozub John , Aly Al , Ossoff Robert , Edwards Glenn 
Published: March 2007

AbstractThe broad background of scattered light observed in spectra of cell suspensions is reduced by factors of up to 20 by immersion refractometry allowing for improved spectroscopic determination of the absorption properties of cells in the 325–820 nm range. Refractive‐index matched spectra of E. coli C1a exhibit a set of resonant features near 422, 561, and 582 nm. Exposure wavelengths are chosen based on this spectrum and cell viability is investigated in E. coli suspensions exposed to 350, 400, 422, 440, and 700 nm radiation delivered in nanosecond pulses with total doses from 500 millijoules to 60 Joules. We observe a loss in cell viability for doses greater than 1 Joule at 422 nm and for all doses at other wavelengths; exposures of less than 1 Joule at 422 nm enhance growth. Excluding exposures at wavelengths within the resonant feature, longer wavelengths are less effective at reducing the viability of E. coli C1a. This indicates the occurrence of at least two absorption processes. © 1992 Wiley‐Liss, Inc.
Effect of aspirin on photodynamic therapy utilizing chloroaluminum sulfonated phthalocyanine (CASP)
Authors: Stern Scott J. , Craig Jock R. , Flock Stephen , Small Susan 
Published: March 2007

AbstractThe efficacy of photodynamic therapy (PDT) is mediated through a direct vascular effect. Interference with platelet function and resulting vascular stasis have been recently demonstrated utilizing the photosensitizer dihematoporphyrin ether (DHE).We examined the effect of aspirin, a known inhibitor of both cyclooxygenase and platelet activity, on PDT using chloroaluminum sulfonated phthalocyanine (CASP). Thirty‐six rats implanted with a window chamber were given either 0.1 mg/kg (low dose) or 10 mg/kg (high dose) aspirin immediately before, immediately after, or 6 hours after the completion of CASP‐PDT. Aspirin in either dosage did not appear to have any effect on the window vasculature when given immediately after light exposure. A moderate inhibition of vascular response was seen in animals treated with aspirin pre‐PDT, whereas high‐dose aspirin completely abrogated the CASP‐PDT vascular response when given 6 hours post‐PDT.These data indicate that aspirin can effect CASP‐PDT in both time‐dependent and dose‐dependent fashions. © 1992 Wiley‐Liss, Inc.
Ultrafast imaging of tissue ablation by a XeCl excimer laser in saline
Authors: Preisack Melitta B. , Neu Walter , Nyga Ralf , Wehrmann Manfred , Haase Karl K. , Karsch Karl R. 
Published: March 2007

AbstractTo determine the temporal evolution of laser induced tissue ablation, arterial wall specimens with either hard calcified or fatty plaques and normal tissue were irradiated in a 0.9% saline solution using a XeCl excimer laser (wavelength 308 nm, energy fluence 7 J/cm2, pulse width 30 ns) through a 600 μm fused silica fiber pointing perpendicular either at a 0.5 mm distance or in direct contact to the vascular surface. Radiation of a pulsed dye laser (wavelength 580 nm) was used to illuminate the tissue surface. The ablation process and the arising bubble above the tissue surface were recorded with a CCD camera attached to a computer based image‐processing system. Spherical cavitation bubbles and small tissue particles emerging from the irradiated area have been recorded. The volume of this bubble increased faster for calcified plaques than for normal tissue. © 1992 Wiley‐Liss, Inc.
Treatment of lupus pernio with the flashlamp pulsed dye laser
Authors: Goodman Matthew M. , Alpern Kenneth 
Published: March 2007

AbstractLupus pernio, a form of cutaneous sarcoidosis usually affecting the face, is often disfiguring and resistant to therapies, both medical and surgical. To our knowledge, there have been no previous reports of laser therapy for this condition. We describe a case of nasal lupus pernio successfully managed with the flashlamp pulsed dye laser. © 1992 Wiley‐Liss, Inc.
Immediate retinal adhesion by CO2 laser irradiation using a fiberoptic intraocular probe
Authors: Derowe Ari , Bartov Elisha , Treister Giora , Belkin Michael , Katzir Abraham 
Published: March 2007

AbstractUsing an experimental fiberoptically guided CO2 laser system, we produced lesions on fresh bovine retinas. These lesions were shown to achieve immediate measurable chorioretinal adhesion. This model provides preliminary data on the use of a fiberoptic CO2 laser probe to produce chorioretinal lesions and possible future use in intraocular surgery for retinal detachment. The advantages of using CO2 laser energy are minimal damage surrounding desired lesion and its versatility as a coagulator and cutter. With modifications, CO2 endolaser may have a role in intraocular surgery. © 1992 Wiley‐Liss, Inc.
Interstitial Nd:YAG laser ablation in normal rabbit liver: Trial to maximize the size of laser‐induced lesions
Authors: Matsumoto Reiko , Selig Abby M. , Colucci Vincent M. , Jolesz Ferenc A. 
Published: March 2007

AbstractIn order to apply interstitial laser ablation to relatively small liver tumors in humans, it will be necessary to optimize the irradiation schedule. Nd:YAG laser was applied to normal rabbit liver in vivo at various power and energy outputs, including a protocol in which irradiation was repeated twice, with and without fiber tip advancement during the intermission. Ex vivo and in vivo tissue were also irradiated to determine the effect of perfusion on the lesion size. We obtained the same monotonic relationship between laser settings and lesion size in rabbit liver as we previously reported in rat liver. MR‐guided fiber advancement between heating periods increased the transverse diameter of the lesion, and MR monitoring demonstrated this process. Our results suggest that repeated irradiation with brief intermissions, when combined with fiber advancement, may increase the lesion size. © 1992 Wiley‐Liss, Inc.
Absorption characteristics at 1.9 μm: Effect on vascular welding
Authors: Kung Robert T. V. , Stewart Robert B. , Zelt David T. , L'ltalien Gilbert J. , Lamuraglia Glenn M. 
Published: March 2007

AbstractA 1.9 μm laser was used to investigate the acute weld strengths for anastomoses of rat and rabbit aortas and femoral arteries. The wall thicknesses for these vessels approximately matched the optical absorption depth of 125 μm for 1.9 μm radiation in vascular tissues. A low power (150 mW) 1.9 μm laser was used. Laser power was delivered through silica fiber optics for manual control. The fiber tip was held approximately 1 mm from the target resulting in a laser spot size of 0.7 mm at the tissue. The linear delivery rate was approximately 0.3 mm/sec. Acute burst pressures of the welds showed a linear correlation with the reciprocal of the vessel radius. These results suggest that the product of the weld strength times the optical absorption depth is constant over the range of vessel sizes studied. A weld strength for a weld thickness equal to the optical absorption depth was determined to be 4 × 106 dynes/cm2, which is comparable to the strength of sutured anastomoses. These acute studies suggest that a laser wavelength with absorption depth in tissue matched to the vessel wall thickness should yield optimum welds. Therefore, a laser operating near 1.9 μm is suitable for small vessel welding. © 1993 Wiley‐Liss, Inc.
Viable bacteriophage in CO2 laser plume: Aerodynamic size distribution
Authors: Matchette L. Stephanie , Vegella Thomas J. , Faaland Robert W. 
Published: March 2007

AbstractThe size of CO2 laser generated plume particles containing viable bacteriophage, ΦX174, was determined with 2 models (10–830 and 15–500) of Andersen bioaerosol cascade impactors. Samples were collected during 100 one‐second laser exposures (approximately 68 W/cm2) of a bacteriophage‐agar substrate with and without a space‐confining hood. The hood appeared to facilitate collection of the largest particles (P < 0.1). In addition, Andersen model 15–500 was a more efficient collector of the largest particles, a phenomenon which is likely a function of the dynamic nature of the laser plume as well as impactor design. We found that laser plume particles containing viable bacteriophage are very large, in one instance exhibiting a count median aerodynamic diameter (CMAD) and mass median aerodynamic diameter (MMAD) of 23 and 55 μm, respectively. Furthermore, the appearance of viable bacteriophage in these plume particles constitutes an extremely rare event. The limitations of cascade impactor design when used to analyze particles with high water concentrations generated in a laser plume are discussed. © 1993 Wiley‐Liss, Inc.
Laser induced wounds and scarring modified by antiinflammatory drugs: A murine model
Authors: Hædersdal Merete , Poulsen Thomas , Wulf Hans Christian 
Published: March 2007

AbstractScarring is a well‐known side effect to cutaneous laser treatment. Therefore we investigated if wounds and scarring could be decreased by pharmacological interference in the acute inflammatory reaction following laser therapy.A copper vapor laser operating at 578 nm was used at three different intensities and doses. The antiinflammatory drugs meth‐ylprednisolone (1 mg/kg/24 h) and indomethacin (2 mg/kg/24 h) were administered through the drinking water. The laser induced wounds were evaluated daily and histologic and biochemical analyses were used to estimate scarring.The administration of antiinflammatory drugs resulted at some laser intensities in increased scores of maximum wound area, healing time, cumulated wound area, fibrosis, hydroxyproline, and hydroxylysine, being mostly pronounced for indomethacin at 0.8 W/spot. The maximum wound area and the wound healing time could be used as a predictor of scarring. A dose response was shown between the laser intensities and the mentioned parameters.We recommend carefulness in the laser treatment of patients receiving indomethacin and disrecommend use of the drug in the prophylaxis against laser induced scarring. © 1993 Wiley‐Liss, Inc.
Sub ablation effects of the KTP laser on wound healing
Authors: Kyzer Michael D. , Aly Al S. , Davidson Jeffrey M. , Reinisch Lou , Ossoff Robert H. 
Published: March 2007

AbstractThe KTP laser (wavelength 532 nm) was used in a sub ablative format to determine the effect of low energy density irradiation on the normal healing by primary intention of scalpel skin incisions in rats. Two longitudinal lased strips were created by a 1 cm diameter defocused beam on the shaved, cleaned dorsal epidermis of 32 Sprague‐Dawley rates; one strip was produced with a 2.0 W beam (54 J, or 18 J/cm2 total dose), and the other with a 3.5 W beam (94.5 J or 31.5 J/cm2, total dose). Scalpel incisions were made longitudinally within the irradiated zones, using contra lateral scalpel incisions on unirradiated skin as controls. Tensio‐metric analysis of wound strength was performed at 3, 7, 14, and 23 days following surgery. The data from fresh tissue tensiometry indicate that KTP laser irradiation of skin incisions results in a lower tensile strength for the wound at 7 and 14 days. The decrease in tensile strength is proportional to the total energy density of the exposure. At days 3 and 23, the tensile strength of the wound was independent of the sub ablative laser exposure. The results are in general agreement with studies of the healing process of laser incisions and may help us to understand the details of the healing process from laser incisions. © 1993 Wiley‐Liss, Inc.
Structural changes in dental enamel induced by high energy continuous wave carbon dioxide laser
Authors: Pogrel M. A. , Muff D. F. , Marshall G. W. 
Published: March 2007

AbstractThe morphological changes in dental enamel exposed to a high energy continuous beam surgical carbon dioxide laser were studied with a wet‐scanning electron microscope. Utilizing a 1 mm focused beam, energy levels of 5, 10, and 12.5 watts were applied to the external enamel surface of teeth for between 0.05 and 2 seconds. Subsequent examination showed melting and resolidi‐fication of the surface enamel. Examination in cross section revealed three different zones of change, which were consistent in thickness. The outer layer of melted and resolidified enamel approximates 100 μm in width, whereas the next zone of acid resistant amorphous enamel measures only 12 μm in width and the third zone of porous enamel measures ∼ 110 μm in width. Though of no immediate practical value in dentistry, the exact physical chemical changes occurring in the enamel warrant further investigation. © 1993 Wiley‐Liss, Inc.
Relation between skin surface temperature and minimal blanching during argon, Nd‐YAG 532, and CW dye 585 laser therapy of port‐wine stains
Authors: Mordon S. , Beacco C. , Rotteleur G. , Brunetaud J. M. 
Published: March 2007

AbstractLaser photocoagulation has proven to be valuable in the treatment of port‐wine stains. In this application, the minimal blanching technique is used as an indicator of suitable dosage since it has been demonstrated that the immediate appearance a white mark is required to achieve permanent blanching a few months later. The objective of the investigations undertaken in this study was to correlate the temperature attained at the surface of port‐wine stains with immediate blanching, upon irradiation with different laser fluences. A comparative study was performed using an argon laser (all lines), a 532 nm Nd:YAG and a 585 nm argon pumped dye laser. Surface temperature was studied using an infrared camera. Temperature was measured on 10 different port‐wine stains using different fluences. Whitening threshold fluence was related to surface temperature. It appeared that whitening threshold fluence corresponded to a surface temperature of 53°C (±3°C). The whitening threshold fluence was dependent on port‐wine stains and wavelength. However, whitening threshold fluence remained lower for 532 nm and 585 nm and it correlated to the absorption curve of hemoglobin. © 1993 Wiley‐Liss, Inc.
Neodymium: YAG contact laser photocoagulation of the in vivo canine epicardium: Dosimetry, effects of various lasing modes, and histology
Authors: Littmann Laszlo , Svenson Robert H. , Chuang Chi Hui , Splinter Robert , Kempler Pal , Norton H. James , Tuntelder Jan R. , Thompson Michelle , Tatsis George P. 
Published: March 2007

AbstractNeodymium:YAG laser photocoagulation (LPC) is an investigational technique for the treatment of drug‐resistant postinfarction ventricular tachycardia that requires cardiopulmonary bypass and open heart surgery. The purpose of this experimental study was to evaluate the feasibility of contact epicardial LPC to reach subepicardial, deep myocardial, and subendocardial regions without ventriculotomy and to analyze the dose‐response relationships of this new technology. In 24 open‐chest, closed heart dogs, a total of 219 epicardial laser lesions were generated under sterile conditions. Laser source was a continuous wave 1064 nm Nd:YAG; the delivery system consisted of a 400 μ bare quartz fiber fed into an 8F electrode catheter in direct contact with the epicardial surface. Laser variables were power at 10–15–20 W; lasing time, 6–12–18–24 s; lasing mode, continuous and pulse‐pause; fiber mode, optical fiber tip inside and extending out from the electrode catheter. Hearts were harvested at 1 week. Histologic measurements included lesion surface diameter, internal diameter, and depth. Results: Significant linear correlation was found between the total delivered energy and all measured lesion parameters. Transmural lesions were found at energy levels of 270–480 J. Maximum depth measured up to 1.68 cm; at high energies, it was limited by myocardial thickness only. At constant energy levels, power and lasing time did not independently affect lesion dimensions; lasing mode and fiber mode had statistically significant but minor effects. Laser lesions were homogeneous and sharply demarcated without epicardial crater or endocardial thrombus formation. Endocardial surface cooling by circulating blood and the presence of epicardial vessels resulted in modifications in lesion morphology. In 29 out of 74 grossly transmural lesions, there was a 0.082 ± 0.127 cm thin surviving subendocardium. Forty‐five coagulation lesions were truly transmural with no surviving myocardial strands. In conclusion, contact epicardial LPC can result in deep, transmural myocardial coagulation lesions. Lesion dimensions can be adequately controlled by total delivered energy. Closed heart epicardial Nd:YAG laser photocoagulation could become a new, less invasive surgical technique for the treatment of drug‐resistant ventricular tachycardia. © 1993 Wiley‐Liss, Inc.
Noncontact determination of skin blood flow using the laser speckle method: Application to patients with peripheral arterial occlusive disease (PAOD) and to type‐I diabetics
Authors: Ruth Bernhard , Schmand Jochen , Abendroth Dietmar 
Published: March 2007

AbstractThe laser speckle method allows the noncontact determination of skin blood flow and its dynamics from a distance of 5 cm. The method is based on the time dependency of the speckle pattern formed by the scattered light of a 5 mW He‐Ne laser (632.8 nm). Utilizing the speckle intensity measured through a pinhole, an electronic circuit generates an output signal denoted as blood flow parameter B. All measurements were carried out on the foot dorsum during steady‐state, ischemia, and reactive hyperemia induced by a 3‐min arterial occlusion. The investigations were carried out in four groups: healthy subjects, asymptomatic smokers, PAOD‐patients, and type‐I diabetics (D) with severe late complications. As shown by parallel measurements with the tcpO2‐method, the initial value Binit of the blood flow parameter B indicates the steady‐state blood flow. Binit decreases significantly from 5.95 ± 2.55 (S.D.) for the control to 4.07 ± 1.69 (PAOD) and 3.81 ± 1.51 (D). The half‐time BTrh for the increase of B at the beginning of the reactive hyperemia is significantly increased from 4.10 ± 2.06 s (control) to 14.5 ± 15.4 s (smokers), 17.6 ± 32.7 s (PAOD), and 5.31 ± 3.55 s (D). Other characteristic values such as peak value and time of peak during the reactive hyperemia as well as the final steady‐state value and the time of its achievement exhibit similar effects. The correlation coefficients between the different characteristic values obtained from the laser speckle method indicate that the characteristic times of the dynamics and the absolute values of B vary separately and provide supplemental information. A two‐dimensional representation of the characteristic values facilitates the differentiation between the four measured groups. © 1993 Wiley‐Liss, Inc.
Effectiveness of corneal neovascularization photothrombosis using phthalocyanine and a diode laser (675 nm)
Authors: Pallikaris Ioannis G. , Tslimbaris Miltiades K. , Iliaki Olga E. , Naoumidi Irina I. , Georgiades Anthimos , Panagopoulos Ioannis A. 
Published: March 2007

AbstractWe used chloroaluminum sulfonated phthalocyanine as a photosensitizer and a diode laser as a light source for induction of photothrombosis of corneal neovascularization. Corneal neovascularization was induced in 1 eye of each of 10 New Zealand white rabbits using intrastromal 6.0 silk sutures. After the intravenous injection of phthalocyanine in a dose of 4 mg per kg of body weight, photothrombosis was carried out using a diode laser emitting at 675 nm. The animals were followed up by both fluorescein angiography and slit‐lamp photography for up to three months. At the end of the follow‐up period the eyes were prepared for histology. After photothrombosis, thrombus formation was induced within new vessels demonstrating histological characteristics of both arterioles and venules. Most of the vessels disappeared or remained closed during the follow‐up period. Recanalization of some of the thrombosed vessels occurred within the first 20 days after the operation. The combination of phthalocyanine and a 675 nm diode laser is effective for the induction of photothrombosis of corneal neovascularization. © 1993 Wiley‐Liss, Inc. © 1993 Wiley‐Liss, Inc.
Transmission of corneal collagen during arf excimer laser ablation
Authors: Ediger M. N. , Pettit G. H. , Weiblinger R. P. , Chen C. H. 
Published: March 2007

AbstractThe time‐resolved transmission of collagen films and 10‐μm sections of bovine cornea during ArF laser ablation has been investigated. The film studies were performed on thin layers of extracted bovine corneal collagen, the principal chromophore in 193 nm photoablation. Transmission measurements were made on both dry and water‐saturated films to assess the sensitivity of the ablation process to hydration. Distinct transient optical changes were observed in both fully desiccated and rehydrated films. Dehydrated films exhibit rapid reduction in film absorption over the time‐course of the ablating laser pulse, presumably due to chromophore bleaching or annihilation. In contrast, rehydrated films demonstrate a short‐lived enhancement of the attenuation. In either case, a single ablative laser pulse increased the long‐term transmission of the film, although this increase was a factor of five greater for dehydrated films than for rehydrated samples. Results obtained from corneal tissue sections were essentially identical to those derived from hydrated collagen films. © 1993 Wiley‐Liss, Inc.
Atherosclerotic tissue analysis by time‐resolved XeCl excimer laser reflectometry
Authors: Pettit G. H. , Sauerbrey R. , Tittel F. K. , Weilbacher D. , Henry P. D. 
Published: March 2007

AbstractThe temporal modification of XeCl laser pulses reflected from human aorta tissue immersed in saline has been studied. Dynamic tissue reflectivity of both normal and atherosclerotic tissues has been examined for various incident pulse fluences between 0.7 and 6.5 J/cm2. Changes in reflected pulse duration are observed for fluences at or above 2.6 J/cm2 with normal tissue targets and 3.0 J/cm2 with calcified plaque. Such reflected pulse analysis may prove useful in identifying tissue targets for ablation during laser angioplasty. © 1993 Wiley‐Liss, Inc.This article is a US Government work and, such, is in the public domain in the United States of America.
Comparative study between pulsed and continuous wave lasers for Photofrin® photodynamic therapy
Authors: Panjehpour Masoud , Overholt Bergein F. , Denovo Robert C. , Petersen Mark G. , Sneed Rick E. 
Published: March 2007

AbstractA study was conducted in the normal canine esophagus to compare continuous wave (CW) and pulsed laser light for photodynamic therapy with Photofrin® (4 mg/kg). Forty‐eight hours postinjection, 630 nm laser light (CW light from an argon‐pumped dye‐laser and pulsed light from a KTP/532‐pumped dye‐laser) was delivered using a 24 mm diameter cylindrical esophageal PDT balloon positioned at either distal or proximal esophagus. A 1.0 cm cylindrical diffuser placed in the center of the balloon delivered 300 J/cm of light at an intensity of 400 mW/cm. Three dogs received CW light proximally and pulsed light distally. Four dogs received CW light distally and pulsed light proximally.The light dose delivered to the esophageal mucosa was measured using three isotropic probes placed on the balloon wall. laser–induced fluorescence technique was used to compare photosensitizer fluorescence intensities at distal and proximal locations. Similar mucosal light doses and drug fluorescence intensities were verified for sites receiving pulsed or CW laser light.Two days after light delivery, the dogs were endoscoped to evaluate the severity of the lesions. While some response variability was observed among different animals, endoscopic examination of the lesions revealed comparable injury from CW and pulsed light in each subject. The animals were then euthanized and necropsies were performed. Based on the gross and histological examination of the lesions, the CW and pulsed laser–induced injuries could not be distinguished. © 1993 Wiley‐Liss, Inc.