bluuebunny/crossref_metadata_2025_split huggingface dataset:
In vitro study examining the effect of sub‐lethal QS 755 nm lasers on the expression of p16INK4a on melanoma cell lines
Authors: Chan Henry H.L. , Xiang Leihong , Leung Joseph C.K. , Tsang Kenneth W.T. , Lai Kar‐neng 
Published: January 2003

AbstractBackground and ObjectivesQ‐switched lasers had been used in the treatment of lentigo maligna but their role remains controversial. While previous studies have addressed the change in adhesion molecule expression after sub‐lethal laser damage, no study has addressed the impact of sub‐lethal laser damage at a molecular level. The p16 gene has been proposed as the candidate gene for melanoma. Our objective is to examine the effect of sub‐lethal laser damage on p16 expression in melanoma cell lines.Study Design/Materials and MethodsThree human melanoma cell lines—HTB 66, Sk‐mel‐24 (HTB 71), and G361—were irradiated by a Q‐switched 755 nm Alexandrite laser at fluencies that ranged from 0.85 to 2.0 J/cm2. HTB 66 was the only cell line with significant expression of p16INK4a while the other two cells lines were p16INK4a negative and served as negative control. Protein and mRNA expression for p16 were assessed by flow cytometry and RT‐PCR, respectively.ResultsThe level of p16INK4a protein in cell line HTB 66 increased significantly after laser irradiation as compared with non‐irradiated cells. The level of p16INK4a protein did not change in p16INK4a‐negative cell lines (Sk‐mel‐24 and G361). However, there was only a slight increase in the percentage of G0/G1 phase cells.ConclusionsSub‐lethal laser damage could increase DNA damage leading to an increase in p16 expression, and such effect would be particularly undesirable for patients with p16 mutation. Further studies are warranted to examine the role of sub‐lethal laser damage in inducing p16 mutation. Lasers Surg. Med. 32:88–93, 2003. © 2003 Wiley‐Liss, Inc.
Cooling efficiency of cryogen spray during laser therapy of skin
Authors: Svaasand L.O. , Randeberg L.L. , Aguilar G. , Majaron B. , Kimel S. , Lavernia E.J. , Nelson J.S. 
Published: January 2003

AbstractBackground and ObjectivesCryogen spray cooling (CSC) is used extensively for epidermal protection during laser‐induced photothermolysis of port wine stains and other vascular skin lesions. The efficacy of CSC depends critically on the heat transfer coefficient (H) at the skin surface for which, however, no reliable values exist. Reported values for H, based on tissue phantoms, vary from 1,600 to 60,000 W/m2 K.Study Design/Materials and MethodsA simple experimental model was designed and constructed, consisting of a pure silver‐measuring disk (diameter 10 mm, thickness ∼1 mm), embedded in a thermal insulator. The disk was covered with a 10 μm thick stratum corneum layer, detached from in vivo human skin. The heat transfer coefficient of the stratum corneum/cryogen interface was measured during CSC with short spurts of atomized tetrafluoroethane.ResultsH was found to be dependent on the specific design of the cryogen valve and nozzle. With nozzles used in typical clinical settings, H was 11,500 W/m2 K, when averaged over a 100 ms spurt, and 8,000 W/m2 K when averaged over a 200 ms spurt.ConclusionsThe presented model enables accurate prediction of H and thus improve control over temperature depth profile and cooling efficiency during laser therapy. Thereby, it may contribute to improvement of therapeutic outcome. Lasers Surg. Med. 32:137–142, 2003. © 2003 Wiley‐Liss, Inc.
Update on non‐ablative light therapy for rejuvenation: A review
Authors: Sadick Neil S. 
Published: January 2003

AbstractBackground and ObjectivesNon‐ablative technologies are playing an increasing role in the management of photoaging. Newer radiofrequency technologies have added to this therapeutic armamentarium. Shorter wavelength technologies are more effective in targeting pilosebaceous vascular and pigmentary alterations while longer wavelength technologies are most effective in wrinkle reduction mediated through dermal remodeling. An overiew of the various technologies available to the practicing laser surgeon are outlined in the present review. Lasers Surg. Med. 32:120–128, 2003. © 2003 Wiley‐Liss, Inc.
Electrosurgical resurfacing: A clinical, histologic, and electron microscopic evaluation
Authors: Sarradet M. Dale , Hussain Mussarrat , Goldberg David J. 
Published: January 2003

AbstractBackgroundRadiofrequency resurfacing is a new technology for ablative facial resurfacing.ObjectivesTo evaluate the efficacy of radiofrequency resurfacing in reduction of perioral and periorbital rhytides, and to assess it's effects on collagen remodeling by electron microscopic evaluation.ResultsFourteen of the fifteen subjects (93%) were 100% re‐epithelialized by day 7. All 15 patients (100%) had resolution of post‐treatment erythema by 3 months. Clinical investigator assessment evaluation revealed mild to moderate improvement in 100% of patients. Histologic changes were consistent with new upper papillary dermal collagen formation. Post‐treatment ultrastuctural changes showed either new Type III or mature Type I collagen formation.ConclusionsRadiofrequency resurfacing is an effective ablative resurfacing method for mild to moderate improvement of Fitzpatrick Type I–III rhytides. It is a low risk procedure with potentially shorter periods of post‐operative re‐epithelialization and erythema as compared to standard ablative laser procedures. Lasers Surg. Med. 32:111–114, 2003. © 2003 Wiley‐Liss, Inc.
Dynamic behavior of cryogen spray cooling: Effects of spurt duration and spray distance
Authors: Aguilar Guillermo , Wang Guo‐Xiang , Nelson J. Stuart 
Published: January 2003

AbstractBackground and ObjectivesCryogen spray cooling (CSC) is used to minimize the risk of epidermal damage during laser dermatologic surgery. Since optimization of CSC permits the safe use of higher light doses, which improves therapeutic outcome in many patients with superficial skin lesions, studies have focused on understanding spray–surface interactions and cooling dynamics. The objective of this study is to measure accurately temperature variations at the sprayed surface and the effects of spurt duration (Δt) and nozzle‐to‐sprayed surface distance (L) on cooling dynamics during CSC.Study Design/Materials and MethodsA fast‐response temperature measurement sensor is built using thin (20 μm) aluminum foil placed on top of a poly methyl‐methacrylate resin (Plexiglass®) with a 50 μm bead diameter thermocouple positioned in between. Liquid film residence time (tr) and minimum surface temperature (Tmin) are systematically measured as a function of Δt and L.ResultsTwo distinct spray–surface interaction mechanisms are recognized. The transition between them occurs at a critical length Lc≈25–30 mm. Noticeable characteristics include: (1) for spurts at L < Lc, shorter tr, and lower Tmin are reached as compared to L > Lc, Tmin is dependent on Δt and L, while tr is a function of Δt only; (2) for spurts at L > Lc, Tmin still depends on L but not on Δt, while tr becomes a function of both Δt and L. Finally, for all Δt, tr reaches a maximum at L = 40 mm.ConclusionsBased on our results, a good choice to achieve low Tmin and tr for the treatment of superficial skin lesions may be met by using Δt of ≈30–50 milliseconds and the shortest spray distance that is tolerable by the patient. Spurt durations (Δt) of more than 30–50 milliseconds at spray distances (L) greater than Lc lead to higher Tmin and longer tr. These parameters may be appropriate for laser therapy of deeper targets. Lasers Surg. Med. 32:152–159, 2003. © 2003 Wiley‐Liss, Inc.
Using a “non uniform pulse sequence” can improve selective coagulation with a Nd:YAG laser (1.06 μm) thanks to Met‐hemoglobin absorption: A clinical study on blue leg veins
Authors: Mordon Serge , Brisot Dominique , Fournier Nathalie 
Published: January 2003

AbstractBackground and ObjectivesEvaluation of the efficacy, on 1–2 mm blue leg telangiectasia, of a 1,064 nm Nd:YAG laser emitting in a non uniform pulse sequence calculated to consider Met‐Hb formation during laser irradiation of a blood vessel.Materials and MethodsA 1,064 nm Nd:YAG laser (Quantel Medical, Athos, France) was used in a non uniform pulse sequence mode, fluences: 300–360 J/cm2 spot: 2 mm, + 5°C contact cooling. The clinical evaluation was performed on 11 female patients, average age: 43 (25–57) years, phototype I–VI. All subjects were previously examined with Doppler ultrasound. A treatment site (6 × 4 cm) was selected on each patient. The topography of the vessels network was reported on a tracing plastic frame before each session and 6 weeks after the last one. These frames were digitized and the number of vessels was determined using the Digitized Tracing Frames Technique. Side effects were noted before and after every treatment, and 6 weeks after the last one. This study lasted for 10 months.Results and DiscussionsPatients tolerated the procedure without anesthesia. Moderate pain, transient erythema and edema, one hyperpigmentation and one matting were noted. There was no hypopigmentation. 55% (P < 0.002) vessels clearance after one session, 86% after two sessions (P < 0.001), and 98% (P < 0.001) after three sessions were obtained. On two patients, the treatment was completed after two sessions with a full clearance. Data reported in this study were obtained thanks to a computerized calculation of vessels clearance. They are similar or superior to those reported in the literature about 1,064 nm Nd:YAG lasers and leg telangiectasia.ConclusionsSince, it was developed to consider the modification of blood absorption and the methemoglobin formation which leads to an increase of the 1.06 μm wavelength absorption, the non uniform pulse mode emphasizes the efficacy of this 1,064 nm Nd:YAG laser concerning the treatment of blue leg veins telangiectasia between 1 and 2 mm. This mode gives the possibility to deliver high energy while preserving the surrounding tissue and leads to a rapid vessel clearance with reduced pain and few side effects when compared to previously published clinical studies using a 1.06 μm laser. Lasers Surg. Med. 32:160–170, 2003. © 2003 Wiley‐Liss, Inc.
Topical rose Bengal: Pre‐clinical evaluation of pharmacokinetics and safety
Authors: Wachter Eric , Dees Craig , Harkins Jay , Scott Timothy , Petersen Mark , Rush Rusty E. , Cada Amy 
Published: January 2003

AbstractBackground and ObjectivesRose bengal (RB) is a potent photosensitizer that has largely been overlooked as a potential photodynamic therapy (PDT) agent. In this study, the feasibility of topical delivery of RB to the epidermis has been evaluated.Study Design/Materials and MethodsTopical formulations of RB were assessed on murine and rabbit skin for pharmacokinetic properties, cutaneous toxicity, and photosensitization.ResultsHydrophilic formulations (≤1% RB) exhibited rapid, selective, uniform delivery to the epidermis, with no significant acute cutaneous toxicity in normal skin. Illumination (532 nm) elicited no acute phototoxicity for light intensities ≤100 mW/cm2 at a light dose of 100 J/cm2; use of higher intensities resulted in superficial thermal damage. Repeat treatment of rabbit skin (weekly for four weeks) elicited minor phototoxicity only at the highest concentration (1% RB).ConclusionsThese results indicate that RB is safe for PDT treatment of skin disorders, exhibiting negligible effects in normal skin. Lasers Surg. Med. 32:101–110, 2003. © 2003 Wiley‐Liss, Inc.
IPL technology: A review
Authors: Raulin Christian , Greve Bärbel , Grema Hortensia 
Published: January 2003

AbstractBackground and ObjectivesIntense pulsed light (IPL) systems are high‐intensity light sources, which emit polychromatic light. Unlike laser systems, these flashlamps work with noncoherent light in a broad wavelength spectrum of 515–1,200 nm. These properties allow for great variability in selecting individual treatment parameters and adapting to different types of skin types and indications. The purpose of this article was to critically review international medical publications of the many indication in which IPL technology can be used, including our own evaluations and experiences.Study Design/Materials and MethodsThe range of therapeutic uses for high‐intensity flashlamps was reviewed, ranging from benign cavernous hemangiomas, benign venous malformations, essential telangiectasias, leg telangiectasias, poikiloderma of Civatte, and port‐wine stains to pigmented lesions, cosmetically undesired hypertrichosis, and facial rhydids. The relative benefits and risks were discussed in detail and compared with other laser systems.ResultsBecause of the wide spectrum of potential combinations of wavelengths, pulse durations, pulse frequency, and fluences, a great deal of experience is required when using IPL technology. Proper patient selection and critical diagnostics serve to keep the adverse effects of the treatment to a minimum.ConclusionsThe distinctive technical conditions involved combine to make IPL technology an alternative and auxiliary treatment option to existing laser systems and conventional therapies. Lasers Surg. Med. 32:78–87, 2003. © 2003 Wiley‐Liss, Inc.
Measurements of laser light attenuation following cryogen spray cooling spurt termination
Authors: Edris Ahmad , Choi Bernard , Aguilar Guillermo , Nelson J. Stuart 
Published: January 2003

AbstractBackground and ObjectivesCryogen spray cooling (CSC) is used to minimize the risk of epidermal damage during laser dermatological surgery. However, while CSC can protect the epidermis from non‐specific thermal damage, the cryogen film on the skin surface may pose a potential problem of laser light attenuation due to optical scattering.Study Design/Materials and MethodsThis study is focused on measuring the light transmittance changes that occur following cryogen spurt termination. The wavelengths studied were chosen for their clinical relevance to treatment of hypervascular skin lesions (594 nm) and laser‐assisted hair removal (785 nm). Following delivery of cryogen spurts to the surface of an epoxy skin phantom, continuous records of light transmittance for 594 and 785 nm were obtained using an integrating sphere‐based light collection apparatus.ResultsShortly after spurt termination, there was negligible light attenuation by the cryogen film at the two wavelengths studied.ConclusionsFor the typical clinical use of a 30 milliseconds spurt duration and 30 milliseconds delay between spurt termination and delivery of the laser pulse, a minimum average transmittance value of ∼97% was measured. Lasers Surg. Med. 32:143–147, 2003. © 2003 Wiley‐Liss, Inc.
Analysis of epidermal protection using cold air versus chilled sapphire window with water or gel during 810 nm diode laser application
Authors: Chang C.W. David , Reinisch Lou , Biesman Brian S. 
Published: January 2003

AbstractBackground and ObjectivesMany cutaneous laser devices incorporate a temperature‐based epidermal protection system to minimize surface damage while continuing to affect targeted tissue. The use of cold air is a new technique to aid in epidermal protection during the application of cutaneous lasers. This study investigates the efficacy of cold air versus chilled sapphire in regards to epidermal preservation when used with an 810 nm diode laser.Study Design/Material and MethodsWhite‐haired pink piglets and dark‐haired pigmented piglets were treated using the 810 nm diode laser in conjunction with either (1) no cryogen protection; (2) cold air alone; (3) chilled sapphire window alone; (4) cold air with water/gel; or (5) chilled sapphire window with water/gel. Laser fluence was varied by adjusting laser duration time while maintaining the intensity at 60 W. Biopsies were obtained from the sacrificed animals, stained with Masson's trichrome, and analyzed for extent of epidermal damage.ResultsAmong white‐haired pink pigs, the cold air afforded the same degree of epidermal preservation as the chilled sapphire window. Epidermal protection was further enhanced with the addition of either gel or water. Among dark‐haired pigmented pigs, the chilled sapphire window alone likewise provided significant epidermal protection, although the cold air alone did not. However, with the addition of water/gel, epidermal preservation was demonstrated in both.ConclusionsCold air is an effective means in promoting epidermal preservation, though slightly inferior to the chilled sapphire window on darkly pigmented subjects. Combining either method with water or gel further enhances surface protection, enabling safe use of higher fluences. Lasers Surg. Med. 32:129–136, 2003. © 2003 Wiley‐Liss, Inc.
Newly designed hydrogel with both sensitive thermoresponse and biodegradability
Authors: Yoshida Takatsune , Aoyagi Takao , Kokufuta Etsuo , Okano Teruo 
Published: February 2003

AbstractThe synthesis and characterization of thermoresponsive hydrogels on the basis of N‐isopropylacrylamide (IPAAm) copolymers crosslinked with biodegradable poly(amino acids) are described. This hydrogel was prepared with two kinds of reactive IPAAm‐based copolymers containing poly(amino acids) as the side‐chain groups and activated ester groups. We introduced the graft chains by decarboxylation polymerization of amino acid N‐carboxyanhydrides initiated from lateral amino groups in the PIPAAm copolymer. The hydrogels easily crosslinked with degradable poly(amino acid) chains by only mixing the copolymer aqueous solutions. The gelling method in this study would provide some of the following innovative features: (1) no necessary removal of unreacted monomers and so forth, (2) simpler loading of drugs into the hydrogels (only mixing when gelling), and (3) easier insertion into the body. On the basis of the swelling ratio measurement of the hydrogel, large volume changes dependent on temperature changes were observed. Moreover, the enzymatic temperature‐dependent degradation was confirmed. The results suggested that these hydrogels could be used for an injectable or implantable matrix of temperature‐modulated drug release. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 779–787, 2003
Synthesis and characterization of two novel star blocks: tCum[poly(isobutylene‐b‐norbornadiene)]3 and tCum[poly(norbornadiene‐b‐isobutylene)]3
Authors: Peetz Ralf M. , Moustafa Ahmed F. , Kennedy Joseph P. 
Published: February 2003

AbstractTwo structurally closely related three‐arm star blocks were synthesized and characterized: tCum(PIB‐b‐PNBD)3 and tCum(PNBD‐b‐PIB)3 [where tCum (tricumyl) stands for the phenyl‐1,3,5‐tris(‐2‐propyl) fragment and PIB and PNBD are polyisobutylene and polynorbornadiene, respectively]. The syntheses were accomplished in two stages: (1) the preparation of the first (or inner) block fitted with appropriate chlorine termini capable of initiating the polymerization of the second (or outer) block with TiCl4 and (2) the mediation of the polymerization of the second block. Therefore, the synthesis of tCum(PIB‐b‐PNBD)3 was effected with tCum(PIB‐Clt)3 [where Clt is tert‐chlorine and number‐average molecular weight (Mn) = 102,000 g/mol] by the use of TiCl4 and 30/70 CH3Cl/CHCl3 solvent mixtures at −35 °C. PNBD homopolymer contamination formed by chain transfer was removed by selective precipitation. According to gel permeation chromatography, the Mn's of the star blocks were 107,300–109,200 g/mol. NMR spectroscopy (750 MHz) was used to determine structures and molecular weights. Differential scanning calorimetry (DSC) indicated two glass‐transition temperatures (Tg's), one each for the PIB (−65 °C) and PNBD (232 °C) phases. Thermogravimetric analysis thermograms showed 5% weight losses at 293 °C in air and at 352 °C in N2. The synthesis of tCum(PNBD‐b‐PIB)3 was achieved by the initiation of isobutylene polymerization with tCum(PNBD‐Clsec)3 (where Clsec is sec‐chlorine and Mn = 2900 g/mol) by the use of TiCl4 in CH3Cl at −60 °C. DSC for this star block (Mn = 14,200 g/mol) also showed two Tg's, that is, at −67 and 228 °C for the PIB and PNBD segments, respectively. It is of interest that the Clsec terminus of PNBD, , readily initiated isobutylene polymerization. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 740–751, 2003
Cationic polymerization of norbornadiene
Authors: Peetz Ralf M. , Moustafa Ahmed F. , Kennedy Joseph P. 
Published: February 2003

AbstractThe polymerization of norbornadiene (NBD) initiated by the 2‐chloro‐2,4,4‐trimethylpentane/titanium tetrachloride system was investigated. Efforts were made to develop conditions for the living polymerization of NBD by the use of proton trap and electron donor in the −35 to −60 °C range however this objective was only partially attained. The molecular weights increased linearly with conversion, and the rate was first‐order in confirmed monomer concentration up to approximately 25%; however, chain transfer became operational beyond this range. The microstructure of polynorbornadiene (PNBD) was investigated by high‐resolution 1H and 13C NMR spectroscopy. According to these techniques, the chain consisted of about equal amounts of exo/exo and exo/endo connected tricyclic repeat units. The head and tail groups were identified and quantitated, and this led to absolute molecular weight determination by integration. Molecular weights obtained by this method and by gel permeation chromatography (relative to polyisobutylene standards) were in good agreement. NMR spectroscopy indicated the presence of small but still identifiable amounts of branching units and their structures. The plot of the glass‐transition temperature against the reciprocal of the number‐average molecular weight was linear and yielded a glass‐transition temperature of 323 °C for the infinite molecular weight polymer. According to thermogravimetric analysis, PNBD was stable up to approximately 250 °C and showed a 5% weight loss at approximately 335 °C. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 732–739, 2003
Catalytic‐chain‐transfer polymerization of styrene revisited: The importance of monomer purification and polymerization conditions
Authors: Roberts G. Evan , Heuts Johan P. A. , Davis Thomas P. 
Published: February 2003

AbstractThe cobaloxime‐mediated catalytic‐chain‐transfer polymerization of styrene at 60 °C was studied with an emphasis on the effects of monomer purification and polymerization conditions. Commonly used purification methods, such as column chromatography and simple vacuum distillation, were not adequate for obtaining kinetic data to be used in mechanistic modeling. A purification regime involving inhibitor removal with basic alumina, followed by polymerization of the styrene in the presence of the cobaloxime and subsequent vacuum distillation, was found to be essential to this end. It was then possible to quantitatively investigate effects such as the initiator concentration and conversion dependencies of the apparent chain‐transfer constant that resulted from the occurrence of cobalt–carbon bond formation. A value of about 9 × 103 was found for the true chain‐transfer constant to cobaloxime boron fluoride, that is, its value in the absence of cobalt–carbon bond formation. Furthermore, previous predictions were confirmed: the measured chain‐transfer constant decreased with increasing initiator concentration and conversion. Finally, it was confirmed that the presence of light increased the amount of free Co(II) catalyst in agreement with other studies. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 752–765, 2003