Laser Light Treatment Research Articles

Assessment the effect of He-Ne laser treatment of Balanites aegyptiaca seeds on the amelioration of active constituents, antioxidant capacity, and anticancer impact in vitro

Background and objective Cancer is still a major health problem worldwide, with an estimated 18.1 million new cases in 2018, and it is expected to increase by 75% by 2030. Chemotherapeutic drugs have disadvantages such as toxicity to noncancerous tissues, drug resistance, and recurrence of cancer. Medicinal plants with their active components have great potential as an important source for novel drug discovery owing to their availability, efficiency, and safety. Searching for new strategies to obtain new drugs with higher efficiency and more safety represents an urgent need. Laser light treatment for seeds is known to improve germination, plant growth, and bioactive substance. The goal of this study was to investigate the effect of laser irradiation on improvement of the phytochemicals compounds and biological activities of Balanites aegyptiaca seeds.Materials and methods The effect of laser pretreatment was investigated at different powers, that is, 25, 50, 100, and 200 mW, with two-time intervals for each power (2 and 4 min), on B. aegyptiaca seeds to enhance the germination and antioxidant activity of the methanolic extracts of their dry plant material through different assays and select the most powerful laser pretreatment extract to evaluate the anticarcinogenic activity on different cell lines.Results and conclusion The results bring to light that the most efficient laser treatment for seeds of B. aegyptiaca was at 200 mW/4 min, which induces the highest yield percentage, total phenolic and flavonoid contents, metal chelating, reducing power, as well as free diphenylpicrylhydrazyl and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activities. Based on these outcomes, the antiproliferative screening assay of the methanolic extracts for the shoots (S) and roots (R) dry plant material of B. aegyptiaca after helium-neon laser treatment at 200 mW for 4 min compared with control was performed on a panel of three cancer cell lines (HepG2, HCT116, and MCF-7) using the sulphorhodamine-B assay, and cytotoxicity was determined using normal BHK fibroblast cell line. Obtained results indicated that these extracts should be regarded as potential anticarcinogenic resources against the HepG2 cell line, displayed moderate activity against MCF-7 and HCT116 cell lines, and exhibited no activity against the growth of the normal BHK cell line. Furthermore, a comparison between these laser-treated extracts, and their mixtures against their control extracts and their mixtures, using the doxorubicin as the reference drug on the HepG2 cell line was in favor of the laser-treated roots and shoots extracts, respectively.

Laser Light Treatment Improves the Mineral Composition, Essential Oil Production and Antimicrobial Activity of Mycorrhizal Treated Pelargoniumgraveolens

Pelargonium graveolens, rose-scented geranium, is commonly used in the perfume industry. P. graveolens is enriched with essential oils, phenolics, flavonoids, which account for its tremendous biological activities. Laser light treatment and arbuscular mycorrhizal fungi (AMF) inoculation can further enhance the phytochemical content in a significant manner. In this study, we aimed to explore the synergistic impact of these two factors on P. graveolens. For this, we used four groups of surface-sterilized seeds: (1) control group1 (non-irradiated; non-colonized group); (2) control group2 (mycorrhizal colonized group); (3) helium-neon (He-Ne) laser-irradiated group; (4) mycorrhizal colonization coupled with He-Ne laser-irradiation group. Treated seeds were growing in artificial soil inculcated with Rhizophagus irregularis MUCL 41833, in a climate-controlled chamber. After 6 weeks, P. graveolens plants were checked for their phytochemical content and antibacterial potential. Laser light application improved the mycorrhizal colonization in P. graveolens plants which subsequently increased biomass accumulation, minerals uptake, and biological value of P. graveolens. The increase in the biological value was evident by the increase in the essential oils production. The concomitant application of laser light and mycorrhizal colonization also boosted the antimicrobial activity of P. graveolens. These results suggest that AMF co-treatment with laser light could be used as a promising approach to enhance the metabolic content and yield of P. graveolens for industrial and pharmaceutical use.

Developmental Stages-Specific Response of Anise Plants to Laser-Induced Growth, Nutrients Accumulation, and Essential Oil Metabolism.

Compared to seeds and mature tissues, sprouts are well known for their higher nutritive and biological values. Fruits of Pimpinella anisum (anise) are extensively consumed as food additives; however, the sprouting-induced changes in their nutritious metabolites are hardly studied. Herein, we investigated the bioactive metabolites, phytochemicals, and antioxidant properties of fruits, sprouts (9-day-old), and mature tissue (5-week-old) of anise under laser irradiation treatment (He-Ne laser, 632 nm). Laser treatment increased biomass accumulation of both anise sprouts and mature plants. Bioactive primary (e.g., proteins and sugars) and secondary metabolites (e.g., phenolic compounds), as well as mineral levels, were significantly enhanced by sprouting and/or laser light treatment. Meanwhile, laser light has improved the levels of essential oils and their related precursors (e.g., phenylalanine), as well as enzyme activities [e.g., O–methyltransferase and 3-Deoxy-D-arabino-heptulosonate-7-phosphate synthase (DAHPS)] in mature tissues. Moreover, laser light induced higher levels of antioxidant and anti-lipidemic activities in sprouts as compared to fruits and mature tissues. Particularly at the sprouting stage, anise was more responsive to laser light treatment than mature plants.

Enhancing biomass and productivity of coumarins and essential oil in ajwain (Trachyspermum ammi) sprouts via laser light treatment

Ajwain, Trachyspermum (T.) ammi, is a coumarin-rich, highly nutritive, and medicinally important herb, however, there is not enough data on the efficiency of laser irradiation in inducing such properties. Herein, the effect of seed treatment with laser irradiations [helium-neon (He-Ne, 632 nm, 5 mW) and helium-cadmium (He-Cd, 460 nm, 16.2 mW)] at 500 mJ energy for 5 min on the biomass, photosynthesis, and the metabolism of coumarins, essential oil, and their precursor metabolites in two varieties of ajwain sprouts i.e., Desi and Chakwal was investigated for the first time. Laser irradiation increased sprout biomass accumulation by improving photosynthesis, chlorophyll content, and respiration. Additionally, laser treatment enhanced the metabolism of coumarins and essential oil, which was explained by the increased availability of their precursors (phenylalanine, cinnamic acid, and shikimic acid). There were also increases in the activity of the key enzymes involved in the biogenesis of phenylpropanoid and coumarins, i.e., 3-Deoxy-D-arabino-heptulosonate-7-phosphate synthase (DAHPS), cinnamate-4-hydroxylase (C4H), 4-coumarate: coenzyme A ligase (4CL), and p-coumarate 3-hydroxylase (C3H). Furthermore, laser treatment induced the accumulation of total and individual phenolics and flavonoids. Consequently, laser treatment significantly improved the antibacterial properties of ajwain sprouts against four foodborne pathogens included Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, and Salmonella spp. Ajwain variety-specific responses to laser light treatment confirmed by principal component analysis (PCA) showed that Desi variety was more responsive. The efficiency of He-Ne was greater than He-Cd laser, which suggests He-Ne laser treatment as a promising approach to boost the production of valuable pigments, coumarins, and essential oils in ajwain sprouts.

Effect of Laser Light on Growth, Physiology, Accumulation of Phytochemicals, and Biological Activities of Sprouts of Three Brassica Cultivars.

Brassica sprouts are known as a good source of antimicrobial bioactive compounds such as phenolics and glucosinolates (GLs). We aim at understanding how He-Ne laser light treatment (632 nm, 5 mW) improves sprout growth and physiology and stimulates the accumulation of bioactive metabolites in three Brassica spp., i.e., mustard, cauliflower, and turnip. Moreover, how these changes consequently promote their biological activities. Laser light improved growth, photosynthesis, and respiration, which induced the accumulation of primary and secondary metabolites. Laser light boosted the levels of pigments, phenolics, and indole and aromatic precursors of GLs, which resulted in increased total GLs and glucoraphanin contents. Moreover, laser light induced the myrosinase activity to provoke GLs hydrolysis to bioactive sulforaphane. Interestingly, laser light also reduced the anti-nutrient content and enhanced the overall biological activities of treated sprouts including antioxidant, antibacterial, anti-inflammatory, and anticancer activities. Accordingly, laser light is a promising approach for boosting the accumulation of beneficial metabolites in Brassica sprouts and, subsequently, their biological activities.

Combined effect of thermal and laser treatment on the destruction of active centers in Bi-doped phosphosilicate fibers

The destruction of laser-active centers in bismuth-doped phosphosilicate fibers exposed to laser light at 532 nm and 1240 nm during annealing at 300 – 600 °C was demonstrated. Both laser radiations were shown to facilitate bleaching of the bismuth-related active centers (BACs), although the rate of this process for 1240 nm is noticeably slower than that of the 532 nm. A phenomenological model including optical excitation processes and thermally activated conversion through a first-order reaction is presented to describe the joint impact of thermal and laser-light treatment. The proposed model is consistent with our experimental data on bleaching and allows us to determine some parameters inherent to the studied process. We demonstrate that the time behavior of the BACs destruction induced with different laser light is characterized by different activation energies. The possible underlying mechanism of the bleaching is discussed taking into account the structural features of phosphosilicate glass.

Laser Light Treatment of Seeds for Improving the Biomass Photosynthesis, Chemical Composition and Biological Activities of Lemongrass Sprouts

Compared to seeds and mature plants, sprouts are well characterized based on their nutritive values and biological properties. Moreover, laser light application is known to be a promising approach to improving plant growth, photosynthesis, and nutraceutical values. However, no studies have investigated the phytochemicals and biological activity of lemongrass (Cymbopogon proximus (Hochst. ex A.Rich.) Chiov.) sprouts or the further improvement of their quality by applying laser light treatment. We carried out a preliminary experiment for the optimization of laser treatment conditions, finding that a helium neon (He–Ne) laser at 632 nm and 5 mW for 5 min provided the most favorable conditions. We then investigated fresh weight, photosynthetic reactions, and primary and secondary metabolites, including sugars, amino acids, organic acids, essential oils, and phenolic compounds. Moreover, we studied the effect of laser light-induced changes in chemical compositions on the antioxidant, anti-diabetic, and anti-cholesterol activities of Cymbopogon proximus sprouts grown from laser-treated seeds. Laser light treatment increased the photosynthesis and respiration and hence the fresh weight of Cymbopogon proximus sprouts. Overall, sprouting increased most bioactive primary and secondary metabolites as compared to seeds. Increased photosynthesis by laser light improved carbon allocation and raised non-structural carbohydrates, which in turn led to improved synthesis of amino acids, organic acids, and essential oils, as well as phenolic and flavonoid compounds. As a result, laser light significantly improved the antioxidant capacity in terms of increasing the levels of ferric reducing antioxidant power (FRAP) (from 9.5 to 21 µmole trolox/g fresh weight (FW)), oxygen radical absorbance (ORAC) (from 400 to 1100 µmole trolox/100 g FW), and DPPH (from 5% to 25% of inhibation) and enhanced the hypocholesterolemic and antidiabetic activity through increasing the percentage of cholesterol micellar solubility (CMS) inhibition (from 42% to 62%) and glycemic index (from 33 to 17 µmole/g) over sprouts and seeds. In conclusion, the synergism of seed laser treatment and sprouting induced the health-promoting bioactive compounds in Cymbopogon proximus as compared to seeds, which can be applied at a large scale to improve the biochemical, physiological, and nutraceutical values of medicinal and crop sprouts.

A235 EFFECTS OF SACRAL PHOTOBIOMODULATION ON THE AUTONOMIC NERVOUS SYSTEM IN PATIENTS WITH COLONIC DYSMOTILITY

BackgroundPatients with chronic refractory constipation show colon dysmotility, including impaired coordination of descending colon-sigmoid colon-rectum-anal sphincter motor functions; this may involve slow colonic transit and colo-anal dyssynergia. Impaired neuronal communication between the sacral defecation center and the distal colon may be causative. In addition, patients with lumbosacral neurological conditions (with lower back pain) may not be able to evoke an effective defecation reflex.AimsTo evaluate if a single therapeutic session of sacral low-level laser therapy (LLLT) would affect the autonomic activity in patients with chronic constipation as revealed by changes in heart rate variability, and to report a multi-session treatment case study.MethodsIn 41 patients with chronic constipation, one session of LLLT was executed, using red LED light at a wavelength of 660 nm for 10 minutes and infrared LED light at wavelength of 840 nm for 10 minutes followed by infrared laser light with wavelength of 825 nm for 20 minutes, while measuring the electrocardiogram. One patient received this treatment 8x over 3 weeks.ResultsThe lumbar-sacral light array treatment showed a significant decrease in parasympathetic activity (RSA & RMSSD) whereas pure sacral laser light treatment showed a significant increase in parasympathetic activity (RSA & RMSSD) as well as a reduction in sympathetic activity (Baevsky’s stress index: SI) (table). A single session of LLLT was also executed during HRCM in 8 patients with some but not all showing evoked colonic motility. Before COVID-19 shutdown, one patient was successfully treated. With a history of chronic constipation without ability to have spontaneous bowel movements for 5 years, symptoms improved from 13 to 8 (on a 20 scale) and quality of life improved from 1.5 to 2.5 (on a 0–4 scale) after 8 sessions. Sympathetic reactivity from supine to standing markedly reduced, from highly elevated measured as the Baevsky index from 55 to 153 s-2 it improved from 42 to 75 s-2 upon standing after 4 sessions. Parasympathetic reactivity did not change.ConclusionsA single session of sacral LLLT markedly affected autonomic nervous activity reflected in changes in HRV. The LLLT is likely affecting the sacral defecation center through peripheral nerves entering and exiting the spinal cord including the dorsal root ganglia. LLLT treatment of a patient with inability to generate spontaneous bowel movements, resulted in ability to have complete evacuations associated with marked reduction in sympathetic reactivity during the supine-standing test, after 4 LLLT sessions. Funding AgenciesCIHRFarncombe Family Digestive Health Research Institute

Laser light as a promising approach to improve the nutritional value, antioxidant capacity and anti-inflammatory activity of flavonoid-rich buckwheat sprouts

Buckwheat sprouts are rich in several nutrients such as antioxidant flavonoids that have a positive impact on human health. Although there are several studies reported the positive impact of laser light on crop plants, no studies have applied laser light to enhance the nutritive values of buckwheat sprouts. Herein, the contents of health-promoting minerals, metabolites and enzymes as well as the antioxidant and anti-inflammatory activities were determined in laser-treated (He–Ne laser, 632 nm, 5 mW) common buckwheat (CBW) and tartarybuckwheat (TBW) sprouts. Out of 49 targeted minerals, vitamins, pigments and antioxidants, more than 35 parameters were significantly increased in CBW and/or TBW sprouts by laser light treatment. Also, laser light boosted the antioxidant capacity and anti-inflammatory activities through inhibiting cyclooxygenase-2 and lipoxygenase activities, particularly in TBW sprouts. Accordingly, laser light could be recommended as a promising method to improve the nutritional and health-promoting values of buckwheat sprouts.

Protective role of carotenoids in the visual cycle.

Exposure to light and accumulation of aberrant visual cycle by-products causes stress in the retina. The physical and chemical properties of carotenoids may provide protection against such scenario. These pigments exist in retinas of many vertebrates, including humans. However, the absence of carotenoids in mice, the preferred ophthalmologic animal model, hindered molecular and biochemical examination of the pigments' role in vision. We established a mouse model that accumulates significant amounts of carotenoids in the retina due to inactivating mutations in the Isx and Bco2 genes. We introduced a robust light damage protocol for the mouse retina using green (532 nm) and blue (405 nm) low-energy lasers. We observed that blue but not green laser light treatment triggered the formation of aberrant retinaldehyde isomers in the retina. The production of these visual cycle by-products was accompanied by morphologic damage in inferior parts of the mouse retina. Zeaxanthin supplementation of mice shielded retinoids from these photochemical modifications. These pigments also reduced the extent of the damage to the retina after the blue laser light insult. Thus, our study discovered a novel role of carotenoids in the visual cycle and indicated that vertebrates accumulate carotenoids to shield photoreceptors from short-wavelength light-induced damage.-Widjaja-Adhi, M. A. K., Ramkumar, S., von Lintig, J. Protective role of carotenoids in the visual cycle.

Research and Application of Laser Light Device for Plant Growth

This paper designs a new laser lighting device for plant growth using main spectroscopy technology by semiconductor laser to synthetize photosynthesis of plants in comparison with natural light (the control group). "Fengxiang" strawberry is used as an experimental material to study the effect of laser light on the growth and fruit quality of strawberry. The results show that the laser light has significantly increased the growth of strawberry plants, and the average fruit weight and plant weight index are higher than the control group. Moreover, soluble solids content, soluble sugar content, solid acid ratio and soluble protein content in strawberry fruit are significantly higher than those of the control group after the laser light treatment. Laser light promotes the realization of strawberry fruit ripening and marketing in advance. In short, the laser light plant growth device improves yield and fruit quality of strawberry greatly, achieves efficiency in production, and has a good prospect in the application and popularization.

Effect of laser diode light irradiation on growth capability of human hair follicle dermal papilla cells.

Low level laser therapy is widely used to relieve pain and inflammation, and to restore cellular functions. The photons of light are absorbed by mitochondria in cells, leading to an increase in the production of adenosine triphosphate (ATP), nitric oxide release, blood flow, and reactive oxygen species (ROS). This study proposed the use of a laser diode array at 808 nm to stimulate the proliferation and to activate the functions of dermal papilla cells, which were an important part of the hair growth cycle. These cells were isolated from human hair follicles and were exposed to 808 nm light at various doses from 0.5, 1, 2.5, 4, and 6 J/cm2. The rate of cell proliferation and the gene expression profile of dermal papilla cells were investigated and compared with the control in which the cells did not received any light treatment. The growth curves of the dermal papilla cells were used to determine the specific growth rates. Higher specific growth rates were observed in the cells exposed to laser at doses higher than 0.5 J/cm2. The effect of the laser light treatment on several gene markers, specifically for dermal papilla cells, was evaluated using real-time polymerase chain reaction (qPCR). Our result shows that collagen type 1 (Col1), alkaline phosphatase (Alp), and versican (Vcan) did not increase when the cells were irradiated by the laser light. Interestingly, sex determining region y-box 2 (Sox2) gene was up-regulated when 0.5 J/cm2, and 1 J/cm2 light was used, while an increase in the level of fibroblast growth factor 7 (Fgf7) gene was observed with light irradiation at 0.5 J/cm2, 1 J/cm2, 2.5 J/cm2, and 4 J/cm2. Too high irradiation dose was shown to yield no effect on the gene expression of dermal papilla cells.

The effectiveness of laser treatments for onychomycosis in adults in the community: a systematic review protocol

Review question/objective The objective of this review is to investigate if laser treatments can effectively treat onychomycosis of the nails in healthy adults living in the community. More specifically, the objectives are to identify: whether the investigated experimental methods, modes and treatment regimens utilizing laser interventions, applied to adults (> 18 years) living in the community with at least one nail infected with onychomycosis, produce outcomes comparable to the current 'gold standard treatment' of oral terbinafine over a minimum 12-week treatment period. Inclusion criteria Types of participants This review will consider studies that include males and females over the age of 18 years who have at least one nail with diagnosed onychomycosis using fungal culture, and direct microscopy, KOH method or periodic acid-Schiff (PAS).Males and females over the age of 18 years with diagnosed diabetes, HIV, cancer, transplant recipients and pregnant females will be excluded. Types of intervention(s)/phenomena of interest Studies that evaluate types of laser therapy for the treatment of onychomycosis including but not limited to; long pulse Nd:YAG laser, Flashlamp pumped short pulsed Nd:YAG 1064nm, 1320nm Nd:YAG laser, modelocked femtosecond pulsed Ti:Sapphire laser, near infra-red Diode lasers, low level laser light treatment inclusive of dose duration and frequency. Types of outcomes This review will consider studies that include the following outcome measures: Primary outcome is cure or clinical response. Cure is defined as positive: 1. Clear nail growth (CNG) defined by at least 3mm growth in three to 12 months, or 2. No dermatophyte isolated from nail samples grown on a mycological culture medium, and 3. Absence of microscopically detectable fungal elements from nail samples treated with KOH, or 4. Absence of microscopically detectable fungal elements using PAS stain, or 5.100% normal nail appearance in three to 18 months plus negative culture and microscopic results. Secondary Outcomes: Compliance rate measured by client attendance for treatments. Recurrence as identified at follow-up at six and/or 12months minimum timeframe. Presence or absence of adverse effects. Adverse affects include skin irritation (erythema) adjacent to the treated nails, nail bed irritation, nail discoloration, onycholysis and periungual burning sensation. Client satisfaction with treatment outcome.

Effect of laser light treatment on some biochemical and physiological processes in seeds and seedlings of white lupine and faba bean

The aim of present study was to determine the changes of some biochemical and physiological processes, which occurred in seeds and seedlings of white lupine and faba bean after pre-sowing treatment with laser beams. It was found this treatment of seeds considerably increased the activity of amylolytic enzymes in seeds of both plants. The greatest differentiation of the enzymatic activity was noticed after 120 h from the time of sowing but the activity of these enzymes in the seeds of both tested plants was similar and it had the same course in time. The irradiated seeds of white lupine and faba bean had higher fresh weight at the time of imbibition than the seeds which were not treated with laser beams. It resulted in earlier and more uniform germination. The concentration of free radicals increased considerably in the seeds pre-treated with laser beams and the largest increase in seeds of both plant species was noticed after five exposures to laser beams. Treating seeds with laser beams considerably increased the amount of indole-3-acetic acid (IAA) in the germinating seeds. Three exposures of seeds caused the largest increase of this plant hormone content in the seeds. The activity of IAA in faba bean was slightly higher than in white lupine seeds. Pre-sowing stimulation with laser had a positive influence on the growth and development of seedlings, which had longer hypocotyl and roots in comparison to seedlings which grew from non irradiated seeds.

The response of Na+/K+-ATPase of human erythrocytes to green laser light treatment

The objective of this study was to investigate the response of Na(+)/K(+)-ATPase of human erythrocytes to green laser irradiation. Effects of green laser light of fluences 9.5-63.3 J.cm(-2) and merocyanine 540-mediated laser light treatment were studied. Isolated erythrocyte membranes (protein concentration of 1 mg/ml) were irradiated by Nd:YAG laser (532 nm, 30 mW) and then incubated in a medium with 2 mM ATP for 30 min. Activity of ATPase was determined colorimetrically by measuring the colored reaction product of liberated inorganic phosphate and malachite green at 640 nm. Contribution of Na(+)/K(+)-ATPase to overall phosphate production was determined using ouabain. A positive effect of green laser light on Na(+)/K(+)-ATPase activity was observed. The dependence of enzymatically liberated inorganic phosphate on light fluence showed a linear correlation (R(2)=0.96, P=0.0005) for all fluences applied (9.5-63.3 J.cm(-2)). On the other hand, MC 540-mediated phototreatment caused a suppression of enzyme activity.

Anastomotic Vessels Remain Viable after Photodynamic Therapy in Primate Models of Choroidal Neovascularization

Anastomotic vessels in exudative age-related macular degeneration (AMD) represent a serious clinical feature that reportedly does not respond well to either photocoagulation or photodynamic therapy (PDT). Anastomoses also occur in various animal models of choroidal neovascularization (CNV). In the present study, anastomotic vessels and their patency were evaluated in two primate CNV laser-trauma models after PDT, by using two novel photosensitizers. In cynomolgus (Macaca fascicularis) and squirrel (Saimiri sciureus) monkey eyes (n = 20), matrix placement of laser photocoagulation sites elicited CNV as a component of the development of fibrovascular tissue (FVT). FVT sites received PDT according to specific drug infusion and laser light treatment parameters. FVTs and anastomoses were evaluated by fundus photography, fluorescein angiography, and histologic examination. Anastomoses averaged approximately 48% of FVT sites, with greatest occurrence in the macaque. Although PDT with each photosensitizer effectively produced FVT closure, both retinal vessels and anastomoses remained patent. Although PDT is effective in closing the choroidal neovascularization in FVT, this technique was ineffective in occluding anastomotic vessels and their associated tributaries within the mid- to proximal retina. Various factors (vascular diameter, composition, blood flow, orientation) may contribute to continued anastomotic patency. By convention, such vessels would typically be defined as chorioretinal anastomoses (CRAs); however, continuing studies suggest the possibility that these neovessels constitute dual-origin hybrids. Regardless of origin, viable anastomoses provide one potential mechanism for revascularization to occur after PDT and may help to explain why CRAs are considered a poor prognostic sign in patients with AMD.

Lasers in dermatology – State of the art

Abstract Owing to the increasing diversity of technological developments and to the resulting versatility of treatment options, the range of laser applications in dermatology has been expanding rapidly. A large variety of benign skin disorders originating from diverse epithelial, adnexal, vascular or other tissue elements, but also many disease-related or acquired cutaneous lesions as well as signs of aged skin or disorders of hair growth can be amenable to laser light treatment. In fact, modern laser technology does improve the majority of such cases either by means of appropriate wavelengths targeting vascular or pigmented lesions or by laser ablation widely utilized to superficially remove circumscribed disorders and moreover for skin resurfacing purposes mainly in photodamaged skin areas. As a consequence, we meanwhile face a broad number of potential indications in Dermatology. Nevertheless, also non-ablative skin rejuvenation techniques using intense pulsed light sources (IPL technology) or radiofrequency (RF) devices for a non-optical energy delivery as well as the introduction of photodynamic therapy have noticeably influenced today's concepts especially with regard to skin rejuvenation purposes.

Effect of Tumor Host Microenvironment on Photodynamic Therapy in a Rat Prostate Tumor Model

Tumor host microenvironment plays an important role in tumor growth, metastasis, and response to cancer therapy. In this study, the influence of tumor host environment on tumor pathophysiology, photosensitizer distribution, and photodynamic therapy (PDT) treatment effect was examined in the metastatic at lymph node and lung (MatLyLu) rat prostate tumor. MatLyLu tumors implanted in different host environment [i.e., orthotopically (in the prostate) or s.c.] were compared for difference in vessel density, average vessel size, vascular permeability, tumor vascular endothelial growth factor production, and tumor oxygenation. Uptake of photosensitizer verteporfin in tumors in both sites was determined by fluorescence microscopy. To compare tumor response to PDT, both orthotopic and s.c. MatLyLu tumors were given the same doses of verteporfin and laser light treatment, and PDT-induced tumor necrotic area was measured histologically. Orthotopic MatLyLu tumors were found to grow faster, have higher vessel density and more permeable vasculature, have higher vascular endothelial growth factor protein levels, and have lower tumor hypoxic fraction than the s.c. tumors. Uptake of photosensitizer verteporfin in the orthotopic tumor was higher than in the s.c. tumors at 15 minutes after injection (1 mg/kg, i.v.), and became similar at 3 hours after injection. For the vascular targeting PDT treatment (0.25 mg/kg verteporfin, 50 J/cm(2) at 50 mW/cm(2), 15 minutes drug-light interval), there was no significant difference in PDT-induced tumor necrotic area between the orthotopic and s.c. tumors, with 85% to 90% necrosis in both types of tumors. However, tumor necrosis induced by the cellular targeting PDT (1 mg/kg verteporfin, 50 J/cm(2) at 50 mW/cm(2), 3 hours drug-light interval) was significantly different in the orthotopic (64%) versus the s.c. (29%) tumors. Tumor host environment can significantly affect photosensitizer verteporfin distribution and PDT treatment effect. Verteporfin-PDT regimen targeting tumor cells is more sensitive to such influence than the vascular targeting PDT. Our study showed the importance of tumor host environment in determining tumor physiologic properties and tumor response to PDT. To obtain clinically relevant information, orthotopic tumor model should be used in the experimental studies.

Speckle-contrast monitoring of tissue thermal modification.

Measurements of the contrast value of time-averaged speckle-modulated images of cartilage tissue are used to study tissue thermal modification in the case of laser-light treatment. This modification is related to thermally induced internal stress relaxation in the matrix of the treated tissue. The specific feature of the evolution of time-averaged speckle contrast with a change in the current temperature of modified collagen tissue is the typical looplike form of the contrast-temperature dependencies associated with irreversible changes in tissue structure and correlated with changes in the tissue diffuse transmittance and the tissue internal stress mentioned by other researchers.

Anthracycline derivatives as photosensitizing agents in photodynamic laser therapy: an in vitro study with squamous epithelial cancer cells of the mouth cavity

Photodynamic laser therapy performed with hematoporphyrin derivatives has become increasingly important in the treatment of well-defined tumors in superficial sites. Limitations of this procedure result from the side effects of hematoporphyrin derivatives. In searching for possible alternatives to the usual photosensitizing agents, we studied the cytostatic drugs adriamycin and epirubicin. In order to evaluate the photodynamic effects of these agents we conducted in vitro studies on isolated cells from a squamous cell carcinoma of the oral cavity. The light source employed was an argon laser with wavelengths at 488/514 nm. Comparison of the cytostatic effect achieved by these anthracycline derivatives with and without laser light treatment showed a pronounced photodynamic effect. These results may herald new photodynamic therapeutic modalities.