Effects of 830 and 670 nm laser on viability of random skin flap in rats.

OBJECTIVE: This study aimed to investigate the effect of 830 and 670 nm diode laser on the viability of random skin flaps in rats. BACKGROUND DATA: Low-level laser therapy (LLLT) has been reported to be successful in stimulating the formation of new blood vessels and reducing the inflammatory process after injury. However, the efficiency of such treatment remains uncertain, and there is also some controversy regarding the efficacy of different wavelengths currently on the market. MATERIALS AND METHODS: Thirty Wistar rats were used and divided into three groups, with 10 rats in each. A random skin flap was raised on the dorsum of each animal. Group 1 was the control group, group 2 received 830 nm laser radiations, and group 3 was submitted to 670 nm laser radiation (power density=0.5 mW/cm(2)). The animals underwent laser therapy with 36 J/cm(2) energy density (total energy=2.52 J and 72 sec per session) immediately after surgery and on the 4 subsequent days. The application site of laser radiation was one point at 2.5 cm from the flap's cranial base. The percentage of skin flap necrosis area was calculated on the 7th postoperative day using the paper template method. A skin sample was collected immediately after to determine the vascular endothelial growth factor (VEGF) expression and the epidermal cell proliferation index (KiD67). RESULTS: Statistically significant differences were found among the percentages of necrosis, with higher values observed in group 1 compared with groups 2 and 3. No statistically significant differences were found among these groups using the paper template method. Group 3 presented the highest mean number of blood vessels expressing VEGF and of cells in the proliferative phase when compared with groups 1 and 2. CONCLUSIONS: LLLT was effective in increasing random skin flap viability in rats. The 670 nm laser presented more satisfactory results than the 830 nm laser.

A delivery system to avoid self-aggregation and to improve in vitro and in vivo skin delivery of a phthalocyanine derivative used in the photodynamic therapy.

The hydrophilic character and aggregation phenomena exhibited by the photosensitizer zinc phthalocyanine tetrasulfonate (ZnPcSO(4)) make it difficult for this compound to penetrate the skin, and reduce the compound's photodynamic efficacy. A microemulsion (ME) was developed to increase the skin penetration of ZnPcSO(4) while avoiding its aggregation. Ternary phase diagrams composed of surfactants (Span® 80/Tween® 80), canola oil and a propylene glycol (PG)/water mixture (3:1) were constructed as a basis for choosing an adequate ME preparation. Rheological, electrical conductivity, dynamic light scattering and zeta potential studies were carried out to characterize the ME formulations. Monomerization of ZnPcSO(4) in the ME was determined photometrically and fluorometrically. In vitro skin penetration and retention of the compound in the skin were measured using porcine ear skin mounted on a diffusion cell apparatus. The in vivo accumulation 6h after ZnPcSO(4) application was determined fluorometrically in hairless mice skin. Confocal laser scanning microscopy was used to visualize ZnPcSO(4) distribution in the skin. A ME composed of canola oil:surfactant:PG-water at 38:47:15 (w/w/w) was chosen for ZnPcSO(4.) This was oil-in-water with internal phase diameter of 15.7±0.15nm. Spectroscopic techniques confirmed that the ME was able to keep ZnPcSO(4) in its monomeric form. In the in vitro penetration of ZnPcSO(4) in the stratum corneum (SC) and in epidermis (without stratum corneum) with dermis ([E+D]) was 33.0- and 28.0-fold higher, respectively compared to the control solution of the drug. In vivo studies, confirmed that when the ME was used as carrier, ZnPcSO(4) concentrations in the SC and [E+D] were about 1.6- and 5.6-fold higher, respectively, than controls. Visualization of ZnPcSO(4) skin penetration by confocal laser scanning microscopy confirmed that the ME increased both penetration and biodistribution of this photosensitizer in the skin.

An outbreak of scalp white piedra in a Brazilian children day care.

White piedra is a superficial mycosis caused by Trichosporon spp. that affects the hair shaft of any part of the body. It is presented an outbreak of scalp white piedra seen in 5.8% of the children frequenting a day care in Northeastern of São Paulo State, Brazil. Mycological exam and culture identified T. cutaneum in all five cases, and scanning electron microscopy of nodules around hair shaft infected by Trichosporon spp. is demonstrated comparing them with those of black piedra and with nits of Pediculous capitis.

An outbreak of scalp white piedra in a Brazilian children day care / Surto de piedra branca afetando os cabelos do couro cabeludo de crianças em creche brasileira

White piedra is a superficial mycosis caused by Trichosporon spp. that affects the hair shaft of any part of the body. It is presented an outbreak of scalp white piedra seen in 5.8 percent of the children frequenting a day care in Northeastern of São Paulo State, Brazil. Mycological exam and culture identified T. cutaneum in all five cases, and scanning electron microscopy of nodules around hair shaft infected by Trichosporon spp. is demonstrated comparing them with those of black piedra and with nits of Pediculous capitis.

Piedra branca caracteriza-se por ser micose superficial, causada por Trichosporon spp., que compromete a haste dos pelos de qualquer região do corpo. Um surto de piedra branca, afetando os cabelos do couro cabeludo, foi registrado em 5,8 por cento das crianças que freqüentavam uma creche na região nordeste do estado de São Paulo. Exame micológico direto e cultura identificaram T. cutaneum nas cinco crianças afetadas. Enfatiza-se a utilização da microscopia eletrônica de varredura, que mostrou nódulos circundando a haste dos cabelos infectada por Trichosporon spp., comparando-os com nódulos de Piedra nigra e com lêndeas de Pediculus capitis.

Reverse hexagonal phase nanodispersion of monoolein and oleic acid for topical delivery of peptides: in vitro and in vivo skin penetration of cyclosporin A.

PURPOSE: To obtain and characterize reverse hexagonal phase nanodispersions of monoolein and oleic acid, and to evaluate the ability of such system to improve the skin penetration of a model peptide (cyclosporin A, CysA) without causing skin irritation. METHODS: The nanodispersion was prepared by mixing monoolein, oleic acid, poloxamer, and water. CysA was added to the lipid mixture to obtain a final concentration of 0.6% (w/w). The nanodispersion was characterized; the skin penetration of CysA was assessed in vitro (using porcine ear skin mounted in a Franz diffusion cell) and in vivo (using hairless mice). RESULTS: The obtainment of the hexagonal phase nanodispersion was demonstrated by polarized light microscopy, cryo-TEM and small angle X-ray diffraction. Particle diameter was 181.77 +/- 1.08 nm. At 0.6%, CysA did not change the liquid crystalline structure of the particles. The nanodispersion promoted the skin penetration of CysA both in vitro and in vivo. In vitro, the maximal concentrations (after 12 h) of CysA obtained in the stratum corneum (SC) and in the epidermis without stratum corneum (E) + dermis (D) were approximately 2 fold higher when CysA was incorporated in the nanodispersion than when it was incorporated in the control formulation (olive oil). In vivo, 1.5- and 2.8-times higher concentrations were achieved in the SC and [E+D], respectively, when the nanodispersion was employed. No histopathological alterations were observed in the skin of animals treated with the nanodispersion. CONCLUSION: These results demonstrate that the hexagonal phase nanodispersion is effective in improving the topical delivery of peptides without causing skin irritation.

Liquid crystalline phases of monoolein and water for topical delivery of cyclosporin A: characterization and study of in vitro and in vivo delivery.

Reverse cubic and hexagonal phases of monoolein have been studied as drug delivery systems. The present study was aimed at investigating whether these systems enhance the cutaneous penetration of cyclosporin A (CysA) in vitro (using porcine ear skin) and in vivo (using hairless mice). Different mesophases were obtained depending on CysA concentration. CysA at 4% allowed the formation of reverse cubic and hexagonal phases in a temperature range of 25-40 degrees C. At 8%, CysA induced the formation of other phases, which might be due to an interaction between the polar groups of the peptide and monoolein. In vitro, the cubic phase increased the penetration of CysA in the stratum corneum (SC) and epidermis plus dermis ([E+D]) at 12 h post-application. The reverse hexagonal phase increased CysA penetration in [E+D] at 6 h and percutaneous delivery at 7.5 h post-application. In vivo, both liquid crystalline phases increased CysA skin penetration. Topical application of these systems, though, induced skin irritation after a 3-day exposure. These results demonstrate that liquid crystalline systems of monoolein are effective in optimizing the delivery of peptides to the skin. The skin irritation observed after topical application of cubic and hexagonal phases should be minimized for their safe use as topical delivery systems.

Glycerol monooleate/solvents systems for progesterone transdermal delivery: in vitro permeation and microscopic studies

A liberaçäo transdérmica de muitos fármacos é dificultada pelas características de barreira do estrato córneo. Promotores químicos de absorçäo cutânea säo capazes de interagir com os constituintes do estrato córneo, induzindo aumento temporário e reversível na permeabilidade da pele. O objetivo deste trabalho foi avaliar a influência de sistemas monoleína (monoleato de glicerol)/solventes na absorçäo percutânea de um fármaco lipofílico (a progesterona), através do estrato córneo de camundongos sem pelo, bem como o efeito da monoleína nas características estruturais do estrato córneo, por meio de microscopia eletrônica de varredura...