The influence of morphological distribution of melanin on parameter selection in laser thermotherapy for vascular skin diseases.

Port wine stains (PWSs) are congenital vascular malformations that progressively darken and thicken with age. Currently, laser therapy is the most effective way in clinical management of PWS. It is known that skin pigmentation (melanin content) affects the radiant exposure that can be safely applied to treat PWS. However, the effect of melanin distribution in the epidermis on the maximum safe radiant exposure has not been studied previously. In this study, 10 different morphological distributions of melanin were proposed according to the formation and migration characteristics of melanin, and the two-scale heat transfer model was employed to investigate the influence of melanin distribution on the threshold radiant exposure of epidermis and blood vessels. The results show that melanin distributions do have a strong effect on laser parameter selection. When uniform melanin distribution is assumed, the threshold radiant exposure to damage a typical PWS blood vessel (50 µm diameter) is 8.62 J/cm2 lower than that to injure epidermis. The optimal pulse duration is 1-5 ms for a typical PWS blood vessel of 50 µm when melanin distribution is taken into consideration. PWS blood vessels covered by non-uniformly distributed melanin are more likely to have poor response to laser treatment.

The Effects of Relaxation Before or After Skin Damage on Skin Barrier Recovery: A Preliminary Study.

OBJECTIVES: Psychological interventions administered before wounding can reduce stress and improve healing. However, in many cases, it would be more practical for interventions to be delivered after wounding. This preliminary study investigated whether a brief relaxation intervention could improve healing when administered either before or after skin damage produced by tape stripping in comparison to a control group. METHODS: One hundred twenty-one healthy adults were randomized into one of three groups: (a) relaxation prestripping group, (b) relaxation poststripping group, or (c) no relaxation. Participants completed measures of stress, fatigue, relaxation, and pain. Relaxation consisted of listening to 20 minutes of guided relaxation, whereas the control condition was quiet reading for 20 minutes. Skin barrier function was measured using transepidermal water loss at baseline, immediately after tape stripping and 25 minutes later. RESULTS: Relaxation either before or after tape stripping improved skin barrier recovery compared with the control group (F(2,92) = 3.58, p = .032, partial η = 0.074). Participants who took part in the relaxation intervention were significantly more relaxed and reported greater reductions in pain than the control group did 25 minutes after tape stripping. Perceived stress over the last month was not significantly related to healing. CONCLUSIONS: This study showed that a relaxation intervention had a beneficial effect on skin barrier recovery regardless of whether the intervention was administered before or after wounding. Future research needs to replicate these findings in other wound types and in clinical settings, and investigate the biological mechanisms involved.

[Observation on effect of badu shengji san and its decomposed recipes on morphological changes of injured skin tissues in rats].

OBJECTIVE: To study the effect of Badu Shengji San (BDSJS) and its decomposed recipes on morphological changes of injured skin in rats. METHOD: SD rats with injured skin were treated with BDSJS and its different decomposed recipes for consecutively 14 days. Morphological changes in the injured skin were observed by H&E staining. RESULT: Mercury and lead-containing ingredients significantly decreased epidermal thickness and caused vascular hemorrhage, hyperemia and inflammatory cell infiltration in reticular layer of dermis. The compatible herbs alleviated epidermal thickness and reduced dermal lesions. CONCLUSION: BDSJS' mercury and lead-containing ingredients can accelerate the healing of skin wound and its compatible herbs can relieve the dermis injury induced by mercury and lead.

Effect of aged garlic extract on wound healing: a new frontier in wound management.

Successful wound healing depends upon angiogenesis, and impaired angiogenesis is a hallmark of the chronic wounds encountered with diabetes and venous or arterial insufficiency. To intervene and improve wound closure, it is essential to investigate the effects of different natural remedies in wound healing. The chicken dorsum skin excisional wound assay was used to investigate the influence of different concentrations of aged garlic solution (AGS) on wound healing. Gross, histopathology, scanning electron microscopy (SEM) and computer-based three-dimensional (3D) image-probing techniques were utilized to determine the effects of AGS on wound closure, re-epithelialization, dermal matrix regeneration, and angiogenesis. Ninety chicks, aged 1 week and divided in 6 groups, were topically exposed to different concentrations of AGS for 6 days: control (group A), 1% (group B), 5% (group C), 10% (group D), 15% (group E), and skin lotion (group F). Different patterns, ranging from incomplete to almost complete wound closure, were observed among different groups with highly significant results (P < 0.001) in group E. Histological investigations revealed a positive augment in the re-epithelialization of all AGS exposed wounds. An increase in the number of new loosely packed collagen and maturation of collagen bundles was observed in all treated wounds at days 4 and 6 post-wounding, respectively. Similar results were achieved through SEM of treated wounds. Histological investigations revealed the profuse dose-dependent neovascularization among AGS-treated wounds. Abbott curve, angular spectrum, and different parameters of 3D surface roughness of wounds were also measured for the precise quantification of angiogenesis. A very highly significant (P < 0.001) increase in angiogenesis was observed among all treated groups. No significant change was observed among control and skin lotion-treated groups. These observations substantiate the beneficial use of AGS in the treatment of wounds. Additional studies are needed to study the specific wound-healing mechanisms of chemical, or group of chemicals, present in AGS.

TUNEL assay for histopathologic evaluation of irreversible chromosomal damage following nonablative fractional photothermolysis.

BACKGROUND: Fractional photothermolysis is extremely popular in skin rejuvenation and remodeling procedures. However, the extent of thermal cellular injury beyond the borders of the coagulated microcolumns produced with fractional phototherapy is undefined. METHODS: Six abdominoplasty patients were pretreated with the Lux1540 Fractional Erbium device (Palomar, Inc., Burlington, Mass.) at various clinical laser settings. After tissue excision, the panni were immediately biopsied. Biopsy specimens were fixed in formalin, embedded in paraffin, sectioned, and evaluated with the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL) procedure for cellular necrosis/apoptosis. Tissue was sectioned horizontally and longitudinally to help define the depth and distribution of the microcolumns of injury in a three-dimensional plane. RESULTS: The extent of cellular necrosis/apoptosis at variable depths within the epidermis and dermis was demonstrated successfully with the TUNEL technique. After the Lux1540 treatment, TUNEL-positive nuclei were identified in a vertically oriented fashion that extended from the epidermis into the papillary and reticular dermis, highlighting the areas of injury. The TUNEL-positive nuclei defined lesions that were approximately 175 to 225 microm in diameter and penetrated to variable depths (200 to 900 microm), depending on the fluence used for treatment (18 to 100 mJ). CONCLUSIONS: TUNEL immunofluorescent labeling provided an accurate assessment of cellular damage within and surrounding the microthermal zones of coagulated collagen with respect to column depth and width. Because of its specificity, the TUNEL assay can be a useful adjunct to other histologic stains used to characterize cellular damage and matrix denaturation in skin treated with any fractional ablative or nonablative laser device.

Pápulas queratósicas acrales / Acral keratotic papules

No disponible

Thermal response of human skin epidermis to 595-nm laser irradiation at high incident dosages and long pulse durations in conjunction with cryogen spray cooling: an ex-vivo study.

BACKGROUND AND OBJECTIVES: Improved laser treatment of cutaneous hypervascular lesions is expected by utilizing higher incident dosages, longer pulse durations and longer wavelengths than those currently used in clinical settings. However, simply increasing the incident dosage will also increase the risk of nonspecific thermal injury to the epidermis due to light absorption by melanin. In this study, we investigated the thermal response of human skin epidermis to 595-nm wavelength laser irradiation at high incident dosages (up to 20 J/cm(2)) and long pulse durations (up to 40 milliseconds) in conjunction with cryogen spray cooling (CSC) using ex-vivo human skin samples. STUDY DESIGN/MATERIALS AND METHODS: The Candela V-beam trade mark laser (595-nm wavelength) was used in the experiments. Ex-vivo human skin samples (Fitzpatrick types I-VI) were irradiated at the incident dosages D(0) = 4, 6, 10, 15, and 20 J/cm(2), laser pulse durations tau(laser) = 1.5, 10, and 40 milliseconds, without and with CSC (refrigerant-134A, spurt duration tau(CSC) = 100 milliseconds). Thermal injury to the epidermis was evaluated by histological observations. RESULTS: Under the same incident dosage, longer pulse durations led to reduced thermal injury to the epidermis. Without CSC, no demonstrable thermal injury to the epidermis was observed in skin types I-II irradiated at the incident dosage as high as 15 J/cm(2), and in skin types III-IV at 10 J/cm(2). When CSC was applied, no evidence of thermal injury to the epidermis was present in skin types I-II even when irradiated at the maximum available incident dosage of the laser system (20 J/cm(2)). In skin types III-IV, no demonstrable thermal injury to the epidermis was observed when using incident dosage as high as 15 J/cm(2) in conjunction with CSC. In skin type VI, thermal injury to the epidermis could not be avoided even at the setting D(0) = 4 J/cm(2), tau(laser) = 40 milliseconds in conjunction with CSC. CONCLUSIONS: For a given incident dosage, longer pulse durations help reduce thermal injury to the epidermis. When a 100-millisecond cryogen spurt is applied, thermal injury to the epidermis can be prevented in ex-vivo skin types I-IV when irradiated at higher incident dosages (15-20 J/cm(2)) than those currently used in clinical settings. Further studies on optimizing the CSC parameters in conjunction with the laser irradiation parameters are needed to protect skin types V-VI from thermal injury to the epidermis.

Topical stratum corneum lipids accelerate barrier repair after tape stripping, solvent treatment and some but not all types of detergent treatment.

Topical acetone treatment extracts lipids from the stratum corneum, and disrupts the permeability barrier, resulting in a homeostatic response in the viable epidermis that ultimately repairs the barrier. Recently, we have developed an optimal lipid mixture (cholesterol, ceramide, palmitate and linoleate 4.3:2.3:1:1.08) that, when applied topically, accelerates barrier repair following extensive disruption of the barrier by acetone. The present study determined if topical treatment with this optimal lipid mixture would have beneficial effects following disruption of the barrier by petroleum ether, tape stripping, or by detergent treatment. Also, we determined if barrier repair was accelerated after moderate disturbances of barrier function. Following moderate or extensive disruption of the barrier by acetone or petroleum ether (solvents), or tape stripping (mechanical), application of the optimal lipid mixture accelerated barrier repair. Additionally, following barrier disruption with N-laurosarcosine free acid or dodecylbenzensulphuric acid (detergents), the optimal lipid mixture similarly accelerated barrier repair. However, following disruption of the barrier with different detergents, sodium dodecyl sulphate and ammonium lauryl sulphosuccinate, the optimal lipid mixture did not improve barrier recovery. Thus, the optimal lipid mixture is capable of accelerating barrier repair following disruption of the barrier by solvent treatment or tape stripping (mechanical), and by certain detergents such as Sarkosyl and dodecylbenzensulphuric acid. The ability of the optimal lipid mixture to accelerate barrier repair after both moderate and extensive degrees of barrier disruption suggests a potential clinical use for this approach.