bluuebunny/crossref_metadata_2025 huggingface dataset:
Laser endoscopic sympathectomy for palmar hyperhidrosis
Authors: Kao Ming‐Chien
Published: March 2007

Hyperhidrosis palmaris is a common disorder among the Orientals. Despite numerous therapeutic modalities in practice, none has proved entirely satisfactory. With the introduction of video‐endoscopic surgery, we combined this system with a fiber optic Nd‐YAG laser unit, electrocautery, and a laser Doppler flowme‐ter to design a new and promising therapeutic technique for palmar hyperhidrosis.

General anesthesia with alternating one‐lung ventilation is essential for a safe and smooth endoscopic sympathectomy. An operating endoscope was introduced into thoracic cavity via the second intercostal space and then attached to a CCD camera video system, which provided clear visibility of the sympathetic trunk in most cases. The proper level of the sympathetic trunk was further confirmed with the aid of vasomotor response of the palmar skin resulting from electric stimulation on the related sympathetic trunk. Finally, the confirmed target was precisely vaporized with a low power Nd‐YAG laser through an endoscope.

Twenty patients underwent bilateral symapthectomy, mostly on T2 and its adjacent trunk. This technique did not cause any injury to the lung or bleeding. No Horner's syndrome was produced. It provided a precise ganglionectomy on a confirmed target under clear magnified vision. Consequently, a definite and long‐lasting therapeutic effect seemed warranted. It was considered to be a relative minor and safe procedure causing minimal discomfort and an almost invisible scar without producing serious complications. It also shortened the operation time and hospital stay remarkably in comparison with other open sympathectomy procedures. © 1992 Wiley‐Liss, Inc.
Augmentation of the systemic host anti‐tumor response through laser excision
Authors: Brien Thomas P. , Lanzafame Raymond J. , Nairn John O. , Rogers David W. , Wang Mian Jing , Hinshaw J. Raymond
Published: March 2007

This study examines whether primary laser excision results in augmentation of the systemic host anti‐tumor response to tumor rechallenge. Single R3230AC mammary tumor implants, (0.5 × 0.5 × 1.0 mm), were grown in 112 female Fisher 344 rats. The animals were randomized. Group S tumors were excised by scalpel. Group E was excised with a Surgistat electrocautery (Valley Labs, Boulder, CO). Group CS was excised with a Sharplan 1100 CO2 laser (Sharplan, Allendale, NJ) at 25 watts (W) continuous wave (C W) (0.2 mm spot size) and the wound was “sterilized” with a 5‐mm spot size by gently heating the tissue without blanching. Group K was excised with a KTP/532 laser (Laserscope, San Jose, CA) at 17 W CW using a 400 μ fiber. Group Y was excised with a Sharplan 2100 Nd:YAG laser set at 15W CW using a 0.2 mm clear sapphire tip. A second tumor implant, (0.5 × 0.5 × 1.0 mm), was placed at a remote site 14 days postoperatively. An unoperated control group was implanted. Secondary tumor volumes were measured for 36 days and the mean tumor volumes (MTV) were statistically compared. The MTV in groups CS, K, Y, and E was less than control (P < 0.01). The MTV in groups CS, K, Y, and E was less than group S, although this was not statistically different. Lasers and cautery appear to increase the host response against subsequent tumor challenge. This study corroborates earlier studies of other modalities. Further studies to determine whether this host sensitization is an immune response and to elucidate the mechanisms of this effect are warranted. © 1992 Wiley‐Liss, Inc.
Global status of clinical photodynamic therapy: The registration process for a new therapy
Authors: Marcus Stuart L. , Dugan Margaret H.
Published: March 2007

The clinical use of photodynamic therapy (PDT) has been ongoing for over a decade. However, attempts to apply for approval of the therapy from boards of health for general use began only in 1989. The unique nature of PDT and the resultant changes in the normal drug registration process, as well as steps which are being taken to approve PDT for the treatment of endobronchial lung cancer, superficial bladder cancer and esophageal cancer are described. The current clinical status of PDT in these indications is also reviewed. © 1992 Wiley‐Liss, Inc.
Effect of tissue pressure on contact laser insults
Authors: Wyman Andrew , Sweetland Helen M. , Rogers Kenneth
Published: March 2007

The effect of variations in tissue pressure transmitted through contact laser probes during tissue ablation has been investigated. Weights of 10 and 50 g were transmitted through the tip of the probes onto the gastric and colorectal wall. At all laser energies the depth of tissue vaporization was significantly greater at the higher tissue pressure with perforation of the viscus occurring at laser energies above 10 J. The lateral zones of thermal tissue necrosis were not influenced by tissue pressure. Deformation of the wall of the viscus under the pressure of the probe was identified as a sign of excessive tissue pressure likely to result in perforation of any tissue of similar thickness to the normal gastric or colorectal wall. © 1992 Wiley‐Liss, Inc.
He‐Ne laser irradiation of single identified neurons
Authors: Balaban Pavel , Esenaliev Rinat , Karu Tiina , Kutomkina Elena , Letokhov Vladilen , Oraevsky Alexander , Ovcharenko Nikolay
Published: March 2007

Silent (LPa2 and LPa3) and spontaneously active (V3, V5, V17) neurons of subesophageal ganglia of Helix pomatia were irradiated via a 125‐mm fiber probe with a 10‐mW He‐Ne laser (λ = 632.8 nm), and the rate of membrane depolarization, duration of latent period, and probability of spike activity were measured as the functions of light intensity. It was found that silent neurons can not be activated by He‐Ne laser irradiation. When the spontaneously active neurons generating spikes every 7–10 min were irradiated in between their spontaneous spikes, the depolarization of membrane and generation of action potentials occurred as a function of light intensity, I. The probability of spike generation increased until the intensity reached 1 W/cm2, and when 1 = 4 W/cm2 was equal to 1. The depolarization of the membrane had a threshold at I = 0.1 W/cm2, then increased with increasing the intensity, and reached a plateau at I = 0.7 W/cm2 (depolarization rate 0.18 mV/s). Duration of the latent period decreased from 28 s to 17 s when the intensity was increased from 0.05 to 0.3 W/cm2. Further increase of the light intensity, from 0.3 to 1.5 W/cm2, caused a less pronounced change in the duration of the latent period (e.g., latent period equal to 11 s at I = 1.5 W/cm2). © 1992 Wiley‐Liss, Inc.
Neodymium:YAG laser treatment of bladder neck contracture following prostatectomy
Authors: Silber Nahum , Servadio Giro
Published: March 2007

A total of 21 patients with postprostatectomy bladder neck contracture underwent treatment with Nd:YAG laser irradiation. A new 800‐μm hemispherical optical quarz fiber was used in contact technique to produce linear incisions in the scarred tissue. Within 11.2 months, median of follow‐up, there was improvement in the obstructive voiding symptoms in all the patients. Two patients who had still mild contracture in the first follow‐up cystoscopy were managed successfully with a second treatment. Endoscopic application of laser energy in the contact mode enables the immediate vaporization and disintegration of the fibrous area and secondary reepithelization of the bladder neck without scarring. © 1992 Wiley‐Liss, Inc.
Demonstration of synergistic effects of hyperthermia and photodynamic therapy using the chick chorioallantoic membrane model
Authors: Kimel S. , Svaasand L. O. , Hammer‐Wilson M. , Gottfried V. , Cheng S. , Svaasand E. , Berns M. W.
Published: March 2007

The chick chorioallantoic membrane (CAM) model was used to study vascular effects of photodynamic therapy (PDT) and hyperthermia (HPT) and the synergism of these modalities. The CAM is a convenient medium for monitoring the modifications of the vasculature. It is possible to view the CAM and to examine structural changes of individual blood vessels in real tune. Moreover, the CAM is a closed system which lends itself to mathematical modeling of the temporal and spatial temperature profile and in which HPT can be performed quantitatively and to a selected depth, using different lasers. A porphyrin‐type photosensitizer solution was applied to areas of the CAM, defined by teflon O‐rings placed on the surface. Uptake dynamics of the sensitizer into the CAM was determined by analyzing its fluorescence in vivo. The CAM area was irradiated with a dual‐wavelength laser system composed of a dye laser at 644 nm (to induce PDT) and a CO2 laser at 10.6 μm (to bring about HPT). Damage to the CAM vasculature, due to combined PDT + HPT, was compared to the outcome of the separate modalities, and a synergistic effect of about 40% was observed. © 1992 Wiley‐Liss, Inc.
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

The 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

The 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

To 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

Lupus 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

Using 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

In 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

A 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

The 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

Scarring 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

The 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

The 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

Laser 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

Neodymium: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

The 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

We 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

The 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

The 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

A 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.
Cytokine modulation of endothelial cell sensitivity to photodynamic therapy
Authors: Breider Mike A. , Lu Xiaochen , Panjehpour Masoud , Frazier Donita L.
Published: March 2007

The purpose of this study was to determine if recombinant angiogenic cytokines modulate the sensitivity of endothelial cells to the toxic effects of chloroaluminum sulphonated phthalocyanine (AlSPc) photodynamic therapy (PDT). Bovine pulmonary artery endothelial cells in 24‐well tissue culture plates were pretreated for 24 hr with AlSPc and either acidic fibroblast growth factor (FGF), platelet‐derived growth factor (PDGF), tumor necrosis factor‐α (TNF), interleukin‐1‐α (IL‐1), or transforming growth factor‐β (TGF) followed by argon‐pumped dye laser. Endothelial cell damage was monitored with 51chromium release. FGF, TGF, and, to a lesser extent, IL‐1, enhanced the PDT‐mediated damage to endothelial cells, whereas PDGF and TNF did not significantly modulate toxicity. The enhanced endothelial cell damage was seemingly not related to rate of cell proliferation or amount of photoactive drug uptake by the EC. These results suggest that presence of tumor secreted cytokines may enhance PDT‐mediated toxicity of tumor associated endothelial cells. © 1993 Wiley‐Liss, Inc.
Pump/probe transmission measurements of corneal tissue during excimer laser ablation
Authors: Pettit G. H. , Ediger M. N.
Published: March 2007

Transient changes in the transmission of a 355 nm probe pulse through corneal tissue during 193 nm ArF laser ablation have been examined. A significant decrease in collimated transmission of the probe beam was observed for time delays between 10 ns and 1 ms after the 193 nm laser pulse. At 10 ns delay the collimated probe transmission was 70% of the preablation level. Minimum collimated transmission (40%) was observed at 30 μs delay. Transmitted probe examination by both diode array and integrating sphere measurements indicate the observed attenuation is due to scattering of the incident probe beam and not due to absorption. The significant scattering at nanosecond delay times suggests onset of the ablation process during the ArF pulse. Scattering therefore may affect the deposition of the 193 nm radiation in the ablation target. © 1993 Wiley‐Liss, Inc.
In vitro decalcification of aortic valve leaflets with the Er:YSGG laser, Ho:YAG laser, and the cavitron ultrasound surgical aspirator
Authors: Williamson Warren A. , Aretz H. Thomas , Weng Guoxing , Shahian David M. , Hamilton William M. , Pankratov Michail M. , Shapshay Stanley M.
Published: March 2007

This study was designed to compare the efficacy of the erbium: yttrium‐scandium‐gallium‐garnet (Er:YSGG) laser and the holmium:yttrium‐aluminum‐garnet (Ho:YAG) lasers in debriding calcium from freshly explanted aortic valve leaflets and to compare the Er:YSGG laser with the Cavitron ultrasonic surgical aspirator (CUSA). Aortic valve leaflets were freshly explanted from patients undergoing aortic valve replacement for aortic stenosis. Initially, 4 leaflets each were debrided with the Er:YSGG and the Ho:YAG lasers to attempt removal of calcium deposits while preserving the underlying integrity of the leaflets and minimizing thermal damage. The Er:YSGG laser was more effective in doing so with less thermal and photoacoustic damage when compared with the Ho:YAG laser.

Twelve more leaflets each were then debrided with the Er:YSGG laser and the CUSA. The Er:YSGG laser again proved less injurious to the underlying leaflet. The CUSA‐treated leaflets demonstrated shattering and disruption of adjacent tissue as well as collagen fiber exposure. These changes were not seen with the Er:YSGG laser. Because of these properties, the Er:YSGG laser merits further evaluation as a tool for aortic valvuloplasty procedures in selected patients with senescent calcific aortic stenosis. © 1993 Wiley‐Liss, Inc.
Changes in oxidative metabolism of murine spleen following laser and superluminous diode (660–950 nm) irradiation: Effects of cellular composition and radiation parameters
Authors: Karu T. , Andreichuk T. , Ryabykh T.
Published: March 2007

Chemiluminescence (CL) of splenocytes of A/Sn mice was recorded after irradiation of the cells with various individual laser an superluminous diode probes at wavelengths from 660 to 950 nm (pulse repetition rates varying from 4 to 5,000 Hz) and at various doses. Laser radiation was found to increase or suppress the spontaneous CL of splenocytes suspension, the amplitude and the sign of the effect depending on the cellular composition of the samples. Direct correlations between the effect of laser radiation (per cent in changes of CL when irradiated at 820 nm, 1.1.103 J/m2, 292 Hz) and per cent of plasmacytes (r = 0.743, P<0.001), neutrophils (r = 0.650, P<0.001) as well as myelocytes and metamyelocytes (r = 0.505, P<0.01) were established. The correlation with per cent of lymphocytes (r = −0.590, P<0.001) was found to be a reverse one. Dependence of the irradiation effects on dose, pulse repetition rate, and wavelength are presented. © 1993 Wiley‐Liss, Inc.
Analgesic effect of Ga‐Al‐As diode laser irradiation on hyperalgesia in carrageenin‐induced inflammation
Authors: Honmura Akie , Ishii Akemi , Yanase Masahiro , Obata Junichi , Haruki Eiichi
Published: March 2007

This study concerned the effect of Ga‐Al‐As diode laser irradiation (780 nm, continuous wave, 31.8 J/s/cm2, spot size od 0.2 mm, 3 minutes/dose) on hyperalgesia induced in the hind paw of rats by injecting carrageenin. The pressure‐pain thresholds of hind paws were measured by the Randall‐Selitto test for evaluation of hyperalgesia. Two doses of laser irradiation, given to the inflamed region immediately before and after the injection of carrageenin, partially (∼ 50%) inhibited the occurrence of hyperalgesia accompanied with a progression of inflammation. This analgesic effect was equal to that of indomethacin (4 mg/kg, i.o.). In another group, the hyperalgesia was removed almost completely for at least 24 hours by one dose of laser irradiation, which was given 3 hours after the carrageenin injection, whereas the edema was not inhibited. This analgesic effect, however, was partially (∼ 50%) antagonized with a dose of 10 mg/kg (i.p.) of naloxone and totally inhibited with 30 mg/kg. These results suggest that low‐power laser irradiation on inflamed regions of carrageenin‐treated rats has a marked analgesic effect and that certain mechanisms that are not related to endogenous opioids are involved in a part of the mechanisms of the analgesic effects. © 1993 Wiley‐Liss, Inc.
MRI guided interstitial laser therapy in a rat malignant glioma model
Authors: El‐Ouahabi Abdessamad , Guttmann Charles R. G. , Hushek Stephen G. , Bleier Alan R. , Dashner Kathleen , Dikkes Pieter , McL. Black Peter , Jolesz Ferenc A.
Published: March 2007

We have used MR monitoring to guide and evaluate the effects of the Nd:YAG interstitial laser on a well‐characterized rat brain tumor model (C6). MRI was used to determine the tumor size, verify the location of the interstitial probe, and evaluate the size and location of the laser–induced lesion during and after treatment. During laser irradiation, an irreversible loss of signal intensity at the fiber tip and a reversible decrease in signal intensity around it were observed with MRI. None of the treatment protocols affected mean rat survival significantly. Although MRI‐guided interstitial laser therapy appears to be safe and easy, it does not provide a curative treatment for spatially disseminated gliomas where a “target volume” cannot be adequately defined. Better results can be expected, especially in well‐defined tumors, with improvements of both the imaging techniques and the laser treatment protocol. © 1993 Wiley‐Liss, Inc. © 1993 Wiley‐Liss, Inc.
Photodynamic activity of liposome‐delivered Cd‐texaphyrin using tumor‐bearing nude mice
Authors: König Karsten , Genze Felicitas , Miller Kurt , Rück Angelika , Reich Ella , Repassy Denes
Published: March 2007

Photodynamic effects in bladder‐tumor bearing nude mice induced by a krypton ion laser (752.5 nm) after i.v. application of liposome‐delivered cadmium texaphyrin were investigated. Cd‐texaphyrin possesses strong absorption transitions in the far red spectral region (around 760 nm) and a high quantum efficiency of singlet oxygen production. No therapeutic effects were obtained using irradiation 24 hours after administration of the sensitizer, whereas phototreatment 2 hours after application led to significant tumor reduction. This corresponds well with studies on fluorophore‐labeled liposomes indicating highest tumor accumulation 1–2 hours after administration. However, the induced cytotoxic effects were lower than those of HpD. © 1993 Wiley‐Liss, Inc.
Soft tissue studies with 805 nm diode laser radiation: Thermal effects with contact tips and comparison with effects of 1064 nm Nd:YAG laser radiation
Authors: Judy Millard M. , Matthews J. Lester , Aronoff Billie L. , Hults Donald F.
Published: March 2007

This study compares the perioperative depths of thermal coagulation, charring, and incision in rabbit liver, internal anterior abdominal wall skeletal muscle, and abdominal skin and in swine liver and abdominal skin obtained with 805 nm diode laser and 1,064 nm Nd:YAG laser radiation using 300‐μm‐diameter conicaltip and 1,200‐μm‐diameter spherical‐tip contact fibers by hand. Additionally, the total depth of tissue necrosis surrounding incisions made with both lasers and contact tips is determined 48 hours postoperatively in the three tissues, and healing of the liver and abdominal wall muscle 21 and 35 days postoperatively is assessed histologically. Perioperatively determined charring, coagulation, and incision depth obtained in all tissues with either 805 nm or 1,064 nm laser radiation were sensibly equivalent at equal laser power values for each of the two contact tip shapes tested. At equal laser power values, coagulation depths obtained in rabbit abdominal skin using the 300‐μm‐diameter conical tip differed significantly (P ⩽ 0.01) from those values obtained with the 1,200‐μm‐diameter spherical tip. Incision depths obtained with the two different contact tip shapes at equal laser power settings in the different tissues studied differed in a few instances with no apparent pattern relating to tissue type or laser power. Depth of incisions obtained with both laser and tip types increases in the range of 6–12 w, but plateaus in the range 12–18 w in the tissues studied. Incisions obtained with both diode and Nd:YAG laser contact were essentially hemostatic, with self‐limiting oozing at most. Tissue necrosis examined at 48 hours showed invasion of inflammatory cells in liver, abdominal skeletal muscle, and skin; 21 and 35 days postoperatively, histology samples of liver and skeletal muscle showed healing with normal fibrous tissue deposition. Results of this study support the essential equivalency of tissue thermal effects obtained with the 805 nm diode and Nd:YAG lasers in the contact mode and support the use of the diode laser as an alternative medical laser. © 1993 Wiley‐Liss, Inc.
Q‐switched CTE:YAG (2.69 μm) laser ablation: Basic investigations on soft (corneal) and hard (dental) tissues
Authors: Kermani O. , Lubatschowski H. , Asshauer Th. , Ertmer W. , Lukin A. , Ermakov B. , Krieglstein G. K.
Published: March 2007

Ablative infrared lasers either show poor transmission in optical fibers (Er:YAG: 2.94 μm; ErCr:YSGG: 2.79 μm) or are characterized by potential relevant thermal side effects (Ho:YAG: 2.1 μm). The CTE:YAG laser (Cr,Tm,Er doted YAG) emits radiation at a wavelength of 2.69 μm. Efficiently high optical fiber transmission is accomplished (attenuation: < 8db/m for Low‐Hydroxy‐Fused‐Silica (LHFS): 0.3 ppm). Since the laser can easily be run in the Q‐switch mode (pulse duration: 0.5–2.5 μs) thermal side effects of tissue interaction were expected to be low. Laser tissue interaction was studied on soft (porcine and human cornea), as well as on hard (human dental) tissue. Histological and micromorphological examinations were performed by light microscopy and scanning electron microscopy. It was found that ablation rates in corneal tissue increased from 5 to 90 μm/pulse with increasing laser fluences (5.5–20 J/cm2). Collateral thermal damage reached as far as 20 ± 5 μm, and was higher (up to 50 μm) when craters where processed in the contact mode using LHFS‐optical fibers. In comparison to soft tissue ablation, hard dental tissue ablation showed very little increase of ablation rate (1–3 μm/pulse) when higher fluences were applied. In dental tissue processing, the ablative effect was accompanied by a luminescence, indicating the presence of plasma. We conclude that the presented CTE:YAG laser can be considered as an effective tool for a variety of laser surgical applications where high power optical fiber delivery is required and where strong thermal side effects are not desired. © 1993 Wiley‐Liss, Inc.
Ab‐interno erbium (Er):YAG laser sclerostomy with iridotomy in Dutch cross rabbits
Authors: Hill Richard A. , Le Minh T. , Yashiro Hideko , Constan Chris , Treadway Anthony , Stern David , Lesiecki Michael L. , Brown Lisa , Berns Michael W.
Published: March 2007

An ab‐interno technique using a pigmented rabbit model has been developed that uses a pulsed erbium:YAG laser to create an iridotomy with a sclerostomy through the same corneal incision. Laser energy was delivered with an articulated arm terminating in side‐firing (850 or 650 μm OD) or end‐firing (850 or 400 μm OD) fiber optic endoprobes, which allowed iridotomies and sclerostomies, respectively, to be created. Initially, sclerostomies (8–10, 8 mJ/300 μs pulses) and basal iridotomies (1–3, 4 mJ/200 μs pulses) were created with the larger probes. Problems encountered with this technique included corneal decompensation and rapid formation of peripheral anterior synechiae with occlusion of sclerostomies. The smaller endoprobes were then used to create midperipheral iridotomies and sclerostomies utilizing the same energy parameters. Sclerostomies created in this manner remained patent in the first postoperative week until the animals were sacrificed to obtain material for histologic study. © 1993 Wiley‐Liss, Inc.
Current status of infrared fiber optics for medical laser power delivery
Authors: Merberg Glenn N.
Published: March 2007

There are a host of fiber‐optic delivery devices available for use with the Er:YAG, HF, CO, and CO2 lasers at 2.9, 2.8, 5.3, and 10.6 μm wavelengths, respectively. While many of these fibers are not as convenient to use as conventional silica fibers, they offer the ability to deliver infrared laser energy for a wide variety of medical applications. The fundamental attributes of fluoride glass, chalcogenide glass, single‐crystal sapphire, and polycrystalline silver halide optical fibers are reviewed and their practical properties tabulated. © 1993 Wiley‐Liss, Inc.