Comparison of epidermal/dermal damage between the long-pulsed 1064 nm Nd:YAG and 755 nm alexandrite lasers under relatively high fluence conditions: quantitative and histological assessments

OBJECTIVE

The purpose of this study was to compare degrees of epidermal/dermal tissue damage quantitatively and histologically after laser irradiation, to find ideal treatment conditions with relatively high fluence for skin rejuvenation.

BACKGROUND DATA

A number of recent studies have evaluated the clinical efficacy and safety of therapeutic lasers under relatively low fluence conditions.

METHODS

We transmitted the long-pulsed 1064 nm Nd:YAG and 755 nm Alexandrite lasers into pig skin according to different fluences and spot diameters, and estimated epidermal/dermal temperatures. Pig skin specimens were stained with hematoxylin and eosin for histological assessments. The fluence conditions comprised 26, 30, and 36 J/cm2, and the spot diameter conditions were 5, 8, and 10 mm. Pulse duration was 30 ms for all experiments.

RESULTS

Both lasers produced reliable thermal damage on the dermis without any serious epidermal injuries, under relatively high fluence conditions. The 1064 nm laser provided more active fibrous formations than the 755 nm laser, while higher risks for tissue damages simultaneously occurred.

CONCLUSIONS

The ideal treatment conditions for skin rejuvenation were 8 mm diameter with 30 J/cm2 and 10 mm diameter with 26 J/cm2 for the 1064 nm laser, and 8 mm diameter with 36 J/cm2 and 10 mm diameter with 26 J/cm2 for the 755 nm laser.

A proposal of a standardized protocol to evaluate waterproof effect of eyeliner and mascara

OBJECTIVE

Eye make-up products must have waterproofing properties to make sure that their colours do not smudge or wash away easily and remain intact despite water or perspiration. Until now, most research has focused on composition and components of make-up products and not on the level of waterproof. This study aimed to find methods to assess the waterproof degree of eyeliners and mascaras and determine the suitability of these methods.

METHODS

Twenty female subjects were selected to test the waterproof of eyeliners, whereas 20 sets of false eyelashes were used to evaluate the waterproof of mascaras. For evaluating water-resistant properties, after test sites where eyeliners and mascaras were applied were immersed in water and natural drying for over 20 min (not artificial drying by drier etc.), L* value of the eyeliners applied on the forearm before and after the immersions, and intensity analysis values of mascaras applied on the false eyelashes were used to calculate the mean percentage waterproof removal ratio (%WPR). A product was hypothesized to be water resistant if the value for the mean %WPR was ≤50%.

RESULTS

The non-waterproof eyeliners were not waterproof if their mean %WPR was >50%, whereas the waterproof eyeliners were waterproof if their mean %WPR was <50%. For mascaras, the mean %WPR was <50% after 1- to 2-h marks after immersion in water for both non-waterproof and waterproof products. After 3-4 h, the mean %WPR for the non-waterproof mascaras was >50%, rendering them not waterproof, whereas the mean %WPR for the waterproof mascaras was <50%, making them waterproof.

CONCLUSION

We have evaluated the waterproof properties by analysing photographed images of the test sites where eyeliners and mascaras were applied. Results of the comparison between non-waterproof and waterproof eyeliners and mascaras, and the methods used, in particular, will be found useful in evaluating waterproof of other make-up products.

The effects of 1064 nm Nd:YAG laser irradiation under the different treatment conditions for skin rejuvenation: quantitative and histologic analyses

OBJECTIVE

The aim of this study was to estimate heat distributions and evaluate degrees of tissue damages histologically after transmitting therapeutic lasers to find optimum ranges for skin rejuvenation.

BACKGROUND DATA

To treat skin aging, many researchers attempted to evaluate treatment effects for the different approaches. The noninvasive skin rejuvenation method was mostly employed to optimize the therapeutic effects by quantifying the laser conditions. However, current approaches produced low reliability for predicting tissue damage.

METHODS

We transmitted the 1064 nm Nd:YAG laser into a skin-mimicking phantom and pig skin samples according to the different fluences and spot diameters, and analyzed its internal-external temperatures. For histologic analyses, we also stained pig skin samples with hematoxylin and eosin (H&E) and compared degrees of tissue damage. The spot diameter conditions were classified into 5, 8, and 10 mm, and the fluence conditions were divided into 26, 30, and 36 J/cm(2). In addition, the pulse duration was set to 30 ms.

RESULTS

In our experiments, the conditions of a spot diameter of 5 mm with a fluence of 36 J/cm(2) and a spot diameter of 10 mm with a fluence of 26 J/cm(2) yielded the maximum surface temperatures>40°C. Regarding histologic evaluations, we also found that the degrees of internal thermal injuries are worsened as spot diameters and fluences increased.

CONCLUSIONS

We selected the optimum treatment conditions for skin rejuvenation as being the laser condition of a spot diameter of 5 mm with a fluence of 36 J/cm(2) and a spot diameter of 10 mm with a fluence of 26 J/cm(2).

A quantitative evaluation method of skin texture affected by skin ageing using replica images of the cheek

OBJECTIVE

Skin texture is a fine structure of skin surface where the hill and furrow were crossed to form a star shape. This study was performed to establish a quantitative evaluation method of skin texture affected by skin ageing using replica images of the cheek.

METHODS

After producing replicas of the left cheek areas of 80 female subjects, representative replica images were chosen to establish six-level facial skin texture index. Using this new index, skin texture of different-aged subjects was visually assessed by multiple examiners. The number of star configurations was also analysed using the same replica images. Other factors contributing to skin texture, such as skin elasticity, roughness, dermal density, moisture and gloss, were also analysed.

RESULTS

The concordance between skin texture scores evaluated by three researchers was high (0.896), and there was a high correlation between skin texture score and age (r = 0.642). The number of star configurations showed high correlations with skin texture scores (r = 0.753) and with age (r = 0.776). Skin texture scores were highly correlated with skin roughness and dermal density, but not with moisture, gloss and elasticity.

CONCLUSION

This study suggests that visual grading of skin texture score based on new facial skin texture index and quantification of star configurations will be useful in evaluating skin ageing.

Production and characterization of monoclonal antibodies directed to the kringle V and protease domains of human apolipoprotein(a)

Production and use of anti-apolipoprotein(a) monoclonal antibodies (MAbs) specific to single copy regions in the polymorphic lipoprotein(a) (Lp(a)) has been emphasized to be important for the standardization of measurements of the coronary heart disease risk factor, Lp(a). Here, mouse MAbs were prepared against the kringle V (V) and protease (P) domains of human apolipoprotein(a) (apo(a)), which domains are present in single copy in the apo(a) molecule. The cDNA for apo(a)VP was cloned from human liver cDNA library, and the V-P recombinant protein overexpressed in Escherichia coli was used as an antigen for the antibody production. Two antibodies named as MAb(a)20 and MAb(a)23 were finally produced, and they were characterized for their binding specificity and epitopes. The specificity of the antibodies was confirmed by an immunoblotting procedure and an enzyme-linked immunoassay (ELISA). It was shown that the antibodies had little, if any, cross-reactivity with human plasminogen, which is relatively abundant in human serum and is highly homologous (85%) with apo(a) in amino acid (aa) sequence. For epitope analysis, 3'-deletional series of apo(a)VP cDNA were constructed, and expression products of them were analyzed for the binding MAb(a)20 and MAb(a)23 do. It has been revealed that distinct epitopes were recognized by the two MAbs: MAb(a)23 (gamma2b, kappa) bound to the V region about 60 aa downstream from the N-terminal, and MAb(a)20 (gamma1, kappa) bound to the P region close to the C-terminal. A one step-sandwich ELISA system for Lp(a) was developed using MAb(a)20 as a capturing antibody and horseradish peroxidase (HRP)-coupled MAb(a)23 as a detecting antibody. The assay was found to be sensitive and useful for detecting Lp(a) in the range of 4-150 microg/dL (80 pM-3 nM).

Tissue engineered artificial skin composed of dermis and epidermis

We made an artificial skin comprised of a stratified layer of keratinocytes and a dermal matrix with a type I collagen containing fibroblasts. In this work, we showed keratinocyte behavior under primary culture, gel contractions varying with concentration of collagen solution, and cell growth plots in the collagen gel. The optimum behavior of dermal equivalent could be obtained using 3.0 mg/ml collagen solution and attached gel culture. The attached gel culture had a jumping effect of growth factor on cell growth at the lag phase. To develop the artificial skin, 1x10(5) cells/cm2 of keratinocytes were cultured on the dermal equivalent at air-liquid interface. Finally, to overcome the problem that artificial skin of collagen gel was torn easily during suturing of grafting, we prepared histocompatible collagen mesh and attached the mesh to the bottom of the gel. Cultured artificial skins were successfully grafted onto rats.