Volume 5, Issue 3 - Topic Issue: Vascular and skin lesions / Issue Editor: Xiuli Wang

Objective: To explore the effects of 532 nm continuous laser combined with photodynamic therapy (PDT) versus 595 nm pulsed dye laser (PDL) on a chicken comb model of vascular malformation. Study design: Ninety adult male chickens were divided into three groups (A, B and C). One comb side of the chickens was taken randomly as the treatment side, and the other side as the self-control side. Group A was irradiated once with a 532 nm continuous laser after a single intravenous injection of hematoporphyrin monomethyl ether (HMME). In group B treatment side of combs was irradiated once with a 595 nm pulsed dye laser (PDL). In the control group C, the combs were treated neither with photosensitizer nor with irradiation. Results: Compared with the self-control sides, part of the treated combs were blanched after HMME-PDT while the histopathology showed an absence of erythrocytes and the vessel lumina were obliterated, leaving the normal overlying epidermis completely intact. At the same time selective destruction of the capillaries in the target area and obvious reduction of vascular vessel number were seen ( p <0.01). In nine cases (30%) treatment was completely ineffective resulting in a total effective rate of 70% (21 cases). No scar formation was observed at all. After PDL treatment most of the treated combs were blanched while histopathology showed an absence of erythrocytes and the vessel lumina were obliterated, leaving the overlying epidermis with slight injuries and scabs. Here again, destruction of the capillaries in the target area and obvious reduction of vascular vessel number ( p <0.01) were obtained. The total effective rate was 93% (28 cases); in two cases scars occurred. The combs of the control group showed no change compared with self-control sides ( p >0.05). Conclusion: In the chicken comb model it was shown that both 532 nm HMME-PDT and 595 nm PDL treatment could damage capillaries in the superficial dermis of combs. The 532 nm HMME-PDT had fewer side effects compared with 595 nm PDL, but the inefficiency rate of 532 nm HMME-PDT group was higher than the 595 nm PDL group. No significant difference was observed in the macroscopic and histopathological results of both groups ( p >0.05).

The uniformity of light dosimetry is an important parameter that affects the efficacy of photodynamic therapy (PDT). Although this uniformity can be improved by a three-dimensional (3D) digital PDT illumination system, it has a low field-of-view (FOV) utilization rate. A checkerboard calibration method using color coding is proposed to calibrate both the projector and camera of the system with a broad common FOV. Experiments reveal that the proposed method increases the utilization rate by up to three times compared with noncolor-coding methods with almost the same accuracy. A fine distinction of phantom lesions in the 3D system can be obtained by clustering, which may be used to optimize the treatment and light-dosimetry evaluation.

Background and objectives: Antimicrobial photodynamic therapy (aPDT) is a technique that combines the photoactivation properties of an innocuous chromophore or photosensitizer (PS) and light, producing reactive oxygen molecules that trigger cell death processes. In this study the in-vitro application of aPDT to fight fungal infections was investigated using methylene blue (MB) as the PS. Materials and methods: The antimicrobial PDT process was carried out with MB and red laser light (λ=633 nm) to activate the PS. Testing was performed with suspensions of various species of dermatophyte fungi ( Trichophyton mentagrophytes , Microsporum canis and Microsporum gypseum ), including a fungus, which to our knowledge, has not been previously studied using this dye ( Trichophyton tonsurans ). For T. tonsurans further optimization tests were carried out. Results and discussion: The fungicidal effect of MB-aPDT was evident. Microsporum strains were slightly more sensitivity to the treatment than Trichophyton strains. The response of T. tonsurans to aPDT was less than to the other fungi tested under the same conditions, or even with higher fluence. However, repetitive aPDT treatment with very low doses of light can achieve a good effectiveness with this strain effecting total growth inhibition. Light may even disturb fungi growth in some circumstances, especially in strain such as T. tonsurans . Conclusion: This study with Trichophyton and Microsporum strains showed that MB was an effective PS to inhibit fungal growth through aPDT, reaching a total inhibition in most of the fungi tested. It was found that repeated exposure with low-power light within the framework of aPDT treatment can achieve better results than a single exposure at higher power.

Objective: The purpose of this study was to evaluate the in vivo response of two different laser fluences (4 and 8 J/cm 2 ) on molecular markers involved in muscle repair after a cryolesion of the tibialis anterior (TA) muscle. Study design: Forty-eight male Wistar rats were randomly distributed into six groups: control (C); normal/uninjured TA muscle treated with either 4 J/cm 2 (L4J) or 8 J/cm 2 (L8J) laser irradiation; injured TA muscle without treatment (IC); and injured TA muscle treated with either 4 J/cm 2 (IL4J) or 8 J/cm 2 (IL8J) laser irradiation. The injured region was irradiated daily for 5 consecutive days, starting immediately after the cryolesion was set using a GaAlAs laser (continuous wave; wavelength, 830 nm; tip area, 0.0028 cm 2 ; power, 20 mW). The animals were euthanized on the sixth day after injury. The injured right TA muscles were removed for histological evaluation, zymography, and immunoblotting and biotin switch analyses. Nitrite and nitrate plasma levels were measured to evaluate the nitric oxide (NO) production. Results: After low-level laser therapy (LLLT), in both injured treatment groups (IL4J and IL8J) the injured area was reduced, the NO production decreased and the S-nitrosated COX-2 was lowered. Moreover, both laser fluences increased the activity and expression of MMP-2. Conclusion: These results suggest that LLLT, for both fluences, could be an efficient therapeutic approach to modulate molecules involved in injured muscle, accelerating regeneration process.

We report the use of a 577-nm wavelength high-power optically pumped semiconductor laser (HOPSL) to treat 12 patients with multiple recalcitrant non-genital warts that had not responded to conservative and invasive treatment. The patients were treated weekly using a 577 nm HOPSL connected to a scanner device. Ten patients with warts showed complete clearance after treatment. One patient had partial clearance and one did not respond at all. Slight to medium pain (visual analog scale, VAS=2–6) was reported during treatment. After treatment there was no evidence of scarring. After the 6-month follow-up there was no recurrence of the completely cleared warts.

Background: Patients suffering from anal cancer have to undergo different anticancer therapies, including radiotherapy. Radiodermatitis represents a debilitating side effect of radiotherapy, often leading to painful lesions and a suspension of the radiotherapy treatment. No widely recognized treatment of radiodermatitis is currently available. Objective: The present report introduces an innovative technique based on the use of laser light to manage radiodermatitis of the anal region in a decisive fashion. Study design: Two cases of radiodermatitis are presented, the occurrence of which followed combined chemoradiotherapy for anal squamous cell carcinoma. Both patients complained about strong pain, severe itch and spontaneous bleeding from the lesions. In addition, they reported limitations in their daily life activities as well as a negative impact on their quality of life. Both patients received laser irradiation therapy by applying two wavelengths simultaneously (970±15 nm and 660±15 nm) for a total of six laser sessions. The chosen treatment parameters were as follows: peak power, 6 W, 50% duty cycle for 360 s; peak power, 6 W in continuous mode for another 120 s resulting in spatially averaged energy fluences of 67.5 J/cm 2 and 45 J/cm 2 , respectively. Results: Complete healing of the lesions and symptoms was achieved within 2 weeks. Remission of the symptoms continued after 2 months with no documented side effects. Both patients managed to complete the radiotherapy sessions and reported maximum satisfaction with the treatment. Conclusions: These cases can prepare the ground to consider class-IV laser therapy, an innovative option to manage radiodermatitis with predictable effectiveness and a consequent improvement in the quality of life of the patients. Patients experiencing radiodermatitis suffer from pain accompanied by limited independence in daily activities, decreased life quality, and reduced self-esteem which often leads to depression. Resolution of radiodermatitis can result in fewer cases of radiotherapy suspension and a better outcome in the oncological treatment as well as an improved quality of life, usually very quickly.

Objective: A first experience of using a Nd:YAG laser with a wavelength of 1318 nm for limited forms of pulmonary tuberculosis surgery is reported. Subjects and methods: During the period from June 2013 to August 2015 a total of 32 patients (19 men and 13 women) underwent surgery for tuberculous granulomas. The average age of the patients was 37.3 years (median, 36 years; range, 18–61 years). Resections of granulomas were carried out using the laser alone (25 patients) or in combination with suturing devices (seven patients). Results: Overall 39 tuberculomas were removed from the 32 patients. The biggest growth measured 2.4×2.2×3.1 cm, while the smallest measured 0.5×0.5×0.5 cm. Overall, the average surgery time was 57 min (median, 50 min; range, 25–115 min). In the combined resection subgroup (using the laser and staplers), the average surgery time was 75 min (median, 50 min; range, 45–115 min). In the subgroup where lung resection was carried out using the laser alone, the average surgery time was 52 min (median, 45 min; range 25–95 min). Total blood loss during surgery was 53 ml (median, 45 ml; range 10–150 ml), 87 ml (median, 50 ml; range 15–150 ml) in the combined lung resection subgroup and 44 ml (median, 35 ml; range, 10–100 ml) in the laser only resection subgroup. Morphological analysis revealed the following results: a high level of tubercular activity was maintained in 12/39 (31%) resected tuberculous granulomas, a moderate level of tubercular activity was detected in 11/39 (28%) resected masses and remitting activity was identified in 16/39 (41%) resected masses. Along the laser resection line of the lung the edge of a tuberculous growth was found in 10/39 cases (26%). The average post-operative duration of pleural drainage was 3.9 days (median, 3 days; range, 2–9 days) in total, 4.1 days (median, 5 days; range, 2–6 days) in the combined subgroup and 3.8 days (median, 3 days; range, 2–9 days) in the laser-only subgroup. The number of post-operative complications assessed according to the Clavien-Dindo scale was two out of 32 patients (6.2%), with two cases of residual pleural cavities. Post operative mortality was 0%. Conclusion: Our first experience of using the Nd:YAG laser with a wavelength of 1318 nm for the resection of limited forms of tuberculosis demonstrated a high level of efficacy and excellent aero- and hemostatic properties with a low rate of post-operative complications even though the differences between the combined resection and laser-only subgroups were not statistically significant ( p >0.05). However, the method is applicable in surgery of limited forms of lung tuberculosis in different variants, performing pure laser resections and as an additional method for other types of lung resections.