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Lasers in Medical Science May 2024Pulsed dye lasers are used effectively in the treatment of psoriasis with long remission time and limited side effects. It is, however, not completely understood which...
Pulsed dye lasers are used effectively in the treatment of psoriasis with long remission time and limited side effects. It is, however, not completely understood which biological processes underlie its favorable outcome. Pulsed dye laser treatment at 585-595 nm targets hemoglobin in the blood, inducing local hyperthermia in surrounding blood vessels and adjacent tissues. While the impact of destructive temperatures on blood vessels has been well studied, the effects of lower temperatures on the function of several cell types within the blood vessel wall and its periphery are not known. The aim of our study is to assess the functionality of isolated blood vessels after exposure to moderate hyperthermia (45 to 60°C) by evaluating the function of endothelial cells, smooth muscle cells, and vascular nerves. We measured blood vessel functionality of rat mesenteric arteries (n=19) by measuring vascular contraction and relaxation before and after heating vessels in a wire myograph. To this end, we elicited vascular contraction by addition of either high potassium solution or the thromboxane analogue U46619 to stimulate smooth muscle cells, and electrical field stimulation (EFS) to stimulate nerves. For measurement of endothelium-dependent relaxation, we used methacholine. Each vessel was exposed to one temperature in the range of 45-60°C for 30 seconds and a relative change in functional response after hyperthermia was determined by comparison with the response per stimulus before heating. Non-linear regression was used to fit our dataset to obtain the temperature needed to reduce blood vessel function by 50% (Half maximal effective temperature, ET50). Our findings demonstrate a substantial decrease in relative functional response for all three cell types following exposure to 55°C-60°C. There was no significant difference between the ET50 values of the different cell types, which was between 55.9°C and 56.9°C (P>0.05). Our data show that blood vessel functionality decreases significantly when exposed to temperatures between 55°C-60°C for 30 seconds. The results show functionality of endothelial cells, smooth muscle cells, and vascular nerves is similarly impaired. These results help to understand the biological effects of hyperthermia and may aid in tailoring laser and light strategies for selective photothermolysis that contribute to disease modification of psoriasis after pulsed dye laser treatment.
Topics: Animals; Rats; Male; Lasers, Dye; Myocytes, Smooth Muscle; Vasodilation; Temperature; Muscle, Smooth, Vascular; Endothelial Cells; Vasoconstriction; Endothelium, Vascular; Rats, Wistar
PubMed: 38703271
DOI: 10.1007/s10103-024-04070-7 -
ACS Omega Aug 2023The degradation of organic dye pollutants is a critical environmental issue that has garnered significant attention in recent years. To address this problem, we...
The degradation of organic dye pollutants is a critical environmental issue that has garnered significant attention in recent years. To address this problem, we investigated the potential of CaCrO chromite (CCO) as a photocatalyst for the degradation of cationic and anionic dye solutions under sunlight irradiation. CaCrO was synthesized via a sol-gel auto-combustion route and sintered at 900 °C. The Rietveld refined XRD profile confirmed the zircon-type structure of CaCrO crystallized in the tetragonal unit cell with 41/ space group symmetry. The surface morphology of the sample was investigated by field emission scanning electron microscopy (FESEM), which revealed the polyhedral texture of the grains. Energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) studies were carried out to analyze the elemental composition and chemical states of the ions present in the compound. Fourier transform infrared (FT-IR) spectroscopy analysis revealed the vibrational modes corresponding to the tetrahedral and dodecahedral metal oxide bonds. The optical band gap was approximated to be in the range of 1.928 eV by using the Tauc relation. The CaCrO catalyst with different contents (5, 20, 35, and 50 mg) was investigated for its photocatalytic performance for the degradation of RhB dye solution under sunlight irradiation using a UV-Vis spectrometer over the experimental wavelength range of 450-600 nm. The degradation efficacy increased from 70.630 to 93.550% for 5-35 mg and then decreased to 68.720% for 50 mg in 140 min under visible light illumination. The comparative study demonstrates that a higher degradation rate was achieved for cationic than anionic dyes in the order RhB > MB > MO. The highest deterioration (93.80%) was achieved for the RhB dye in 140 min. Equilibrium and kinetic studies showed that the adsorption process followed the Langmuir isotherm and pseudo-second-order models, respectively. The maximum adsorption capacity of 21.125 mg/g was observed for the catalyst concentration of 35 mg. From the cyclic test, it has been observed that the synthesized photocatalyst is structurally and morphologically stable and reusable. The radical trapping experiment demonstrated that superoxide and hydroxyl radicals were the primary species engaged in the photodegradation process. A possible mechanism for the degradation of RhB has been proposed. Hence, we conclude that CaCrO can be used as an efficient photocatalyst for the remediation of organic dye pollutants from the environment.
PubMed: 37636959
DOI: 10.1021/acsomega.3c02457 -
Optics Express Jul 2023We have used photon pair correlations generated via spontaneous parametric downconversion (SPDC) to measure the fluorescence lifetime of the organic dye rhodamine 6 G,...
We have used photon pair correlations generated via spontaneous parametric downconversion (SPDC) to measure the fluorescence lifetime of the organic dye rhodamine 6 G, demonstrating that fluorescence lifetime measurements can be achieved using a continuous wave (CW) laser, without pulsed or modulated lasers. Our entangled photon method, quantum fluorescence lifetime (Q-FL) measurements, uses one photon to excite fluorescence and the resulting fluorescence photon is timed and referenced to the arrival time of the other entangled photon. Thus, we can exploit the short timescale of photon pair correlations to conduct experiments that are typically carried out with pulsed lasers and we show that the inherent timing of the photons is fast enough to resolve the nanosecond scale fluorescence lifetime of the sample. This measurement paves the way towards using the time correlations of entangled photons for fluorescence imaging; capitalizing on the presence of fast, sub-100 ps correlations that have not been demonstrated classically.
PubMed: 37710542
DOI: 10.1364/OE.494744 -
Journal of Burn Care & Research :... Mar 2024Currently, most burn models for preclinical testing are on animals. For obvious ethical, anatomical, and physiological reasons, these models could be replaced with...
Currently, most burn models for preclinical testing are on animals. For obvious ethical, anatomical, and physiological reasons, these models could be replaced with optimized ex vivo systems. The creation of a burn model on human skin using a pulsed dye laser could represent a relevant model for preclinical research. Six samples of excess human abdominal skin were obtained within one hour after surgery. Burn injuries were induced on small samples of cleaned skin using a pulsed dye laser on skin samples, at varying fluences, pulse numbers and illumination duration. In total, 70 burn injuries were performed on skin ex vivo before being histologically and dermato-pathologically analyzed. Irradiated burned skin samples were classified with a specified code representing burn degrees. Then, a selection of samples was inspected after 14 and 21 days to assess their capacity to heal spontaneously and re-epithelize. We determined the parameters of a pulsed dye laser inducing first, second, and third degree burns on human skin and with fixed parameters, especially superficial and deep second degree burns. After 21 days with the ex vivo model, neo-epidermis was formed. Our results showed that this simple, rapid, user-independent process creates reproducible and uniform burns of different, predictable degrees that are close to clinical reality. Human skin ex vivo models can be an alternative to and complete animal experimentation, particularly for preclinical large screening. This model could be used to foster the testing of new treatments on standardized degrees of burn injuries and thus improve therapeutic strategies.
Topics: Animals; Humans; Burns; Skin; Epidermis; Lasers, Dye; Wound Healing
PubMed: 37202124
DOI: 10.1093/jbcr/irad071 -
In Vivo (Athens, Greece) 2024Postoperative scar formation is inevitable, and a gold standard management has not been established to date. Due to the fact long and large scar formation occurs in...
BACKGROUND
Postoperative scar formation is inevitable, and a gold standard management has not been established to date. Due to the fact long and large scar formation occurs in reconstructive surgery, this study analyzed the relationship between various factors in patients who received breast reconstruction using latissimus dorsi (LD) flap to investigate appropriate and effective management approaches.
PATIENTS AND METHODS
Twenty-seven patients who underwent breast reconstruction between June 2014 and January 2015 received laser therapy on their LD donor site at the Kyungpook National University Chilgok Hospital. Scar evaluation was performed on both the surgical scar and intact skin on the contralateral side. Scar evaluation was conducted at five specific points, 2 cm from the midpoint of the scar on each side. Laser treatment was performed at 4-week intervals, and patients were then followed-up for 6 months. To assess scars, gross images were taken using the same settings. In addition, spectrophotometry was used for color assessment, durometer for texture and pressure evaluation, and Vernier calipers and height gauges for a more precise and objective approach.
RESULTS
The mean age of the participants was 45.7 years, and the mean body mass index was 22.1 kg/m The operator-evaluated scar scale scores were 107.2 and 97.3 in the experimental and control groups, respectively. In the patient-rated questionnaire, the scores were 62.3 and 59.4 in the experimental and control groups, respectively.
CONCLUSION
When analyzing early-stage postoperative scars based on various factors, laser therapy is considered a very useful scar management approach. Additionally, when performing reconstructive surgery, tension force is regarded as a significant factor to take into account since it affects scar widening.
Topics: Humans; Middle Aged; Cicatrix; Superficial Back Muscles; Surgical Flaps; Mammaplasty; Laser Therapy; Treatment Outcome
PubMed: 38418124
DOI: 10.21873/invivo.13509 -
The Tokai Journal of Experimental and... Dec 2023Ecchymosis is a common side effect after injury and surgery. A pulsed dye laser (PDL) is the gold standard for vascular lesions and can minimize ecchymosis. Heating...
Ecchymosis is a common side effect after injury and surgery. A pulsed dye laser (PDL) is the gold standard for vascular lesions and can minimize ecchymosis. Heating induces hemoglobin modification due to oxidative and heat reactions with the formation of bilirubin and methemoglobin, resulting in color changes to brown-yellow. Therefore, downtime following cosmetic procedures can be shortened.
Topics: Humans; Ecchymosis; Lasers, Dye; Hot Temperature
PubMed: 37981852
DOI: No ID Found -
Skin Research and Technology : Official... Oct 2023Studies on pulsed dye laser (PDL) have shown the best efficacy and safety data for treating vascular anomalies among the various lasers used and the 595-nm PDL has been...
BACKGROUND
Studies on pulsed dye laser (PDL) have shown the best efficacy and safety data for treating vascular anomalies among the various lasers used and the 595-nm PDL has been used to treat cutaneous vascular anomalies for about 30 years. The purpose of this study was to assess the efficacy of 595 nm Pulsed Dye Laser in the management of facial flat angiomas present in the form of Port-Wine Stain.
MATERIALS AND METHODS
Seven cases of PWS in Fitzpatrick skin type ranged from I to III and colour ranging from pink to purple, were treated with 595 nm pulse Dye Laser. Patients underwent to 6-8 laser sessions at 20-30 days intervals. Results obtained were judged by dermatologist, by comparing pre-treatment and post-treatment photographs, 6 months after the last session and a quartile scale of lesion clearance (4-point Investigator Global Assessment scale): 1 = no or low results (0%-25% of the lesion area improved), 2 = slight improvement (25%-50% of the lesion area cleared), 3 = moderate-good improvement (50%-75%), and 4 = excellent improvement (75%-100%) was used. Possible side effects such as blisters, hyper/hypopigmentation, and scarring were monitored.
RESULTS
All patients observed global improvements. 71% of patients achieved excellent clearance and 29% patients achieved good-moderate clearance of their angioma. Patients were asked for a subjective evaluation of the results: 57% of patients were very satisfied, 29% were satisfied, and 14% patients were not very satisfied with the results. No patients were dissatisfied. No significant side effects were noted.
CONCLUSION
This research confirms the efficacy of the 595 nm PDL for flat angioma management, without considerable side effects.
Topics: Humans; Treatment Outcome; Lasers, Dye; Port-Wine Stain; Cicatrix; Hemangioma
PubMed: 37881052
DOI: 10.1111/srt.13494 -
Polymers Jul 2023Due to the increased application of lasers in different fields (industry, medicine, etc.), there is a growing need for new laser sources with good beam quality and...
Due to the increased application of lasers in different fields (industry, medicine, etc.), there is a growing need for new laser sources with good beam quality and variable emission wavelength. At the same time, for environmental reasons, the obtaining of novel eco-friendly active optical materials, such as those based on the deoxyribonucleic acid (DNA) biopolymer, with optimal light emission properties, is of high interest. The results obtained in this study of the temporal dependence of the transmittance and of the light emission in thin films of DNA-CTMA-Rhodamine 610 (at different Rhodamine concentrations) (DNA-CTMA-Rh610), when they are illuminated with continuous wave laser light at 532 nm (frequently used in the optical pumping of dye lasers), are presented and discussed. The transmittance results obtained for thin film samples are compared to those obtained for the DNA-CTMA-Rh610 solutions in butanol, from which the films have been made, and also with those obtained for Rh610 solutions in butanol with the same concentrations. The investigation was performed in order to assess the influence of the DNA-CTMA and of the green laser light at 532 nm wavelength on relevant chromophore properties such as light transmission and fluorescence emission. The results obtained revealed that the DNA-CTMA matrix has an active influence on the Rhodamine 610 emission, in the whole range of concentrations of the investigated samples.
PubMed: 37514494
DOI: 10.3390/polym15143105 -
Clinical and Experimental Dental... Dec 2023Different surface preparation and treatment methods may have dissimilar effects on the microleakage of composite resin. This study was conducted to determine the...
OBJECTVES
Different surface preparation and treatment methods may have dissimilar effects on the microleakage of composite resin. This study was conducted to determine the deproteinizing effect of 10% bromelain enzyme, 10% papain enzyme, CO , and erbium-YAG laser in regard to decrease in the microleakage of composite restorations.
MATERIALS AND METHODS
Thirty teeth were selected and 60 class V cavities were prepared on the lingual and buccal sides. They were divided into six groups (n = 10): Group 1, phosphoric acid gel; Group 2, bromelain enzyme 10%; Group 3, papain enzyme 10%; Group 4, mixed papain and bromelain enzymes 10%; Group 5, CO laser; and Group 6, erbium-YAG laser. They were stored in basic fuchsine and dye penetration was evaluated. Kruskal-Wallis and Mann-Whitney tests were used for statistical analysis, p < 0.05 RESULTS: In both occlusal and gingival margins, comparison of microleakage between groups 1, 2, 3, 4, and 5 showed no significant differences (p = 1) and group 6 had a significant difference with other groups (p ˂ 0.001).
CONCLUSIONS
Microleakage of composite resin in the dentin surface was not affected significantly using either bromelain or papain 10% enzymes or erbium laser. However, CO laser had a negative effect on the enamel and dentin margins and increased the microleakage. Erbium laser showed a better effect than enzymes on microleakage.
Topics: Humans; Erbium; Carbon Dioxide; Papain; Bromelains; Dental Cavity Preparation; Composite Resins; Lasers, Solid-State; Dental Caries
PubMed: 38037462
DOI: 10.1002/cre2.822 -
Lasers in Medical Science Sep 2023Applications of lasers in phototherapy have been the trend for the last few decades. The photodynamic therapy process normally depends on photosensitizers and laser...
Applications of lasers in phototherapy have been the trend for the last few decades. The photodynamic therapy process normally depends on photosensitizers and laser beams. Through this study, indocyanine green has been used as a photosensitizer, which is normally activated using laser lines between 750 and 805 nm. The activity of the indocyanine green to do fluorescence by other pulsed laser sources has been tested by fluorescence technique, and it has been proven that the laser lines at 810, 940, and 980nm are able to excite the indocyanine green with different extents. The indocyanine green activation has been tested by several laser lines (810, 940, and 980 nm) commonly used as surgical lasers. The generated oxygen has been measured after irradiating the indocyanine green with the different laser lines. A comparison has been made between laser irradiation as a pinpoint and a broad beam. It is found that the wide beam is more effective in activating oxygen production. In the end, it is concluded that lines 810 and 940nm were effective in activating the used dye, while the 980nm activity did not show enough efficiency.
Topics: Reactive Oxygen Species; Indocyanine Green; Photochemotherapy; Photosensitizing Agents; Oxygen; Lasers
PubMed: 37704871
DOI: 10.1007/s10103-023-03876-1