Efficacy of a laser with a pulse duration of 300 ps in skin rejuvenation and treatment of pigmentation disorders in Asians: a series of four cases.

The photothermal effect of lasers is minimized and the photoacoustic effect is maximized as the pulse duration is shortened. Therefore, picosecond lasers with a short pulse and high peak power can be used to effectively treat various pigment disorders by reducing tissue damage. The first picosecond lasers were used for tattoo removal; they are also widely used for pigment treatment because of their reduced side effects compared with nanosecond lasers. Recently, picosecond lasers have been shown to be effective in the treatment of various skin conditions such as acne scars and large pores. There are many studies on picosecond lasers; however, there are no studies on a laser with a pulse duration of 300 ps. This report describes the use of a 300 ps Nd:YAG laser for treating pigment disorders and for skin rejuvenation in four Asians, with no side effects. Determining the clinical significance of the 300 ps pulse duration through comparative studies with various picosecond lasers is needed.

A retrospective analysis of the clinical efficacies of Q-switched Alexandrite and Q-switched Nd:YAG lasers in the treatment of nevus of Ota in Korean patients.

BACKGROUND: While the Q-switched Alexandrite laser (QSAL) and the Q-switched neodymium: yttrium-aluminum-garnet (QSNY) laser have been widely used in treating nevus of Ota, few studies compared them. OBJECTIVE: To compare the efficacies of the QSAL and the QSNY laser in the treatment of nevus of Ota in Korean patients. METHODS AND MATERIALS: A retrospective multicenter study was conducted in 76 patients with nevus of Ota. Thirty-one patients were treated with a QSAL (5.5-8.0 J/cm(2), 4-mm spot size) and 45 patients were treated with QSNY laser (6.0-12.0 J/cm(2), 2-mm spot size). Treatment outcomes were categorized into five grades and the results were compared with the relevant variables taken into account using multivariate logistic regression analysis. RESULTS: QSAL treatment was more likely to achieve a better response compared with that with QSNY laser treatment. The odds ratio of achieving an excellent response, compared with the odds ratio of having a poor response, was 12.213-times more likely when a QSAL was used than when a QSNY laser was used (p = 0.026). CONCLUSION: The QSAL tends to be more efficient than the QSNY laser in the treatment of nevus of Ota in Korean patients. Further controlled, prospective comparison studies are needed.

Atrophic acne scar treatment using triple combination therapy: dot peeling, subcision and fractional laser.

Atrophic scars are a common complication of acne. Many modalities are proposed but each does not yield satisfactory clinical outcomes. Thus, a new combination therapy is suggested that incorporates (i) dot peeling, the focal application and tattooing of higher trichloroacetic acid concentrations; (ii) subcision, the process by which there is separation of the acne scar from the underlying skin; and (iii) fractional laser irradiation. In this pilot study, the efficacy and safety of this method was investigated for the treatment of acne scars. Ten patients received this therapy for a year. Dot peeling and subcision were performed twice 2-3 months apart and fractional laser irradiation was performed every 3-4 weeks. Outcomes were assessed using scar severity scores and patients' subjective ratings. Acne scarring improved in all of the patients completing this study. Acne scar severity scores decreased by a mean of 55.3%. Eighty percent of the patients felt significant or marked improvement. There were no significant complications at the treatment sites. It would appear that triple combination therapy is a safe and very effective combination treatment modality for a variety of atrophic acne scars.

Adaptation of the myoglobin knockout mouse to hypoxic stress.

Myoglobin knockout (myo-/-) mice were previously reported to show no obvious phenotype but revealed several compensatory mechanisms that include increases in cardiac capillary density, coronary flow, and hemoglobin. The aim of this study was to investigate whether severe hypoxic stress can exhaust these compensatory mechanisms and whether this can be monitored on the gene and protein level. Myo-/- and wild-type (WT) mice we e exposed to hypoxia (10% O(2)) fo 2 wk. Thereafter hemodynamic parameters were investigated by invasive measurement combined with magnetic resonance imaging. Cardiac gene and protein expression were analyzed using cDNA arrays and two-dimensional gel electrophoresis plus mass spectrometry, respectively. Hematocrit levels increased from 44% (WT) and 48% (myo-/-) to 72% in both groups. Similar to WT controls, hypoxic myo-/- animals maintained stable cardiovascular function (mean arterial blood pressure 82.4 mmHg, ejection fraction 72.5%). Cardiac gene expression of hypoxic myo-/- mice differed significantly from WT controls in 17 genes (e.g., keratinocyte lipid binding protein +202%, cytochrome c oxidase Vb +41%). Interestingly, hypoxia inducible factor-1alpha remained unchanged in both groups. Proteome analysis revealed reduced levels of heart fatty acid-binding protein and heat shock protein 27 both in hypoxic myo-/- and WT mice. Our data thus demonstrate that myo-/- mice do not decompensate du ing hypoxic st ess but a e surprisingly well adapted. Changes in ene gy metabolism of fatty acids may contribute to the robustness of myoglobin-deficient mice.