Jae Eun Choi

Assessment of dermal toxicity of nanosilica using cultured keratinocytes, a human skin equivalent model and an in vivo model.

Assessments of skin irritation potentials are important aspects of the development of nanotechnology. Nanosilica is currently being widely used for commercial purposes, but little literature is available on its skin toxicity and irritation potential. This study was designed to determine whether nanosilica has the potential to cause acute cutaneous toxicity, using cultured HaCaT keratinocytes (CHK), a human skin equivalent model (HSEM), and invivo model. Nanosilica was characterized by scanning electron microscopy. We evaluated the cytotoxic effects of nanosilica on CHKs and the HSEM. In addition, we also investigated whether two commercially available nanosilicas with different sizes (7 and 10-20 nm) have different effects. To confirm invitro results, we evaluated the irritation potentials of nanosilicas on rabbit skin. Nanosilicas reduced the cell viabilities of CHKs in a dose-dependent manner. However, the HSEM revealed no irritation at 500 microg/ml of nanosilica. Furthermore, this result concurred with Draize skin irritation test findings. The present study data indicate that nanosilica does not cause acute cutaneous irritation. Furthermore, this study shows that the HSEM used provides more useful screening data than the conventional cell culture model on the relative toxicities of NPs.

Treatment of Becker's nevi with a long-pulse alexandrite laser.

BACKGROUND Beckers nevus (BN) can be a distressing cosmetic handicap for patients and a treatment challenge for physicians. Various treatment modalities have been used, but repigmentation commonly occurs after treatment. OBJECTIVE To evaluate the efficacy of long‐pulse alexandrite laser in the treatment of BN. MATERIALS AND METHODS Eleven Korean patients with Fitzpatrick skin type III to V were included in this study. A long‐pulsed alexandrite laser with a wavelength of 755 nm and a pulse duration of 3 ms was used. Patients were treated with a fluence of 20 to 25 J/cm2 and a spot size of 15 to 18 mm. Cryogen spray cooling was not used. RESULTS Two patients had excellent responses, five had good responses, and four had fair responses. Hair density simultaneously decreased with treatment in all patients. Although mild hypopigmentation was observed in some patients, and partial hypertrophic scarring was observed in one patient, the outcomes were cosmetically acceptable. No repigmentation was noted during the follow‐up period. CONCLUSION A long‐pulsed alexandrite laser without cryogen spray cooling is an effective and safe alternative in the treatment of BN. The authors have indicated no significant interest with commercial supporters.

Ablative fractional laser treatment for hypertrophic scars: comparison between Er:YAG and CO2 fractional lasers

Background: Nonablative fractional photothermolysis has been reported to show early promise in the treatment of hypertrophic scars, but there are few reports on ablative fractional photothermolysis for the treatment of hypertrophic scars. Aim: To evaluate and compare the efficacy and safety of Er:YAG fractional laser (EYFL) and CO2 fractional laser (CO2FL) for treatment of hypertrophic scars. Methods: Thirteen patients with hypertrophic scars were treated with 2,940 nm EYFL, and ten were treated with 10,600 nm CO2FL. An independent physician evaluator assessed the treatment outcomes using Vancouver scar scale (VSS) and 5-point grading scale (grade 0, no improvement; grade 1, 1–25%; grade 2, 26–50%; grade 3, 51–75%; grade 4, 76–100% improvement). Patients are queried about their subjective satisfaction with the treatment outcomes. Results: After the final treatment, average percentage changes of VSS were 28.2% for EYFL and 49.8% for CO2FL. Improvement was evident in terms of pliability, while insignificant in terms of vascularity and pigmentation. Based on physicians global assessment, mean grade of 1.8 for EYFL and 2.7 for CO2FL was achieved. Patients subjective satisfaction scores paralleled the physicians objective evaluation.Conclusion: CO2FL is a potentially effective and safe modality for the treatment of hypertrophic scars, particularly in terms of pliability.

A comparison of the scar prevention effect between carbon dioxide fractional laser and pulsed dye laser in surgical scars.

BACKGROUND The use of ablative lasers based on the fractional approach is a novel strategy for the treatment of postoperative and acne scars in addition to wrinkles. OBJECTIVE To evaluate and compare the efficacy of carbon dioxide ablative fractional laser (AFL) and the pulsed dye laser (PDL) for the improvement of surgical scars. MATERIALS AND METHODS Fourteen Korean patients with surgical scars were enrolled for this study. Half of each scar was treated with a 10,600-nm AFL and the contralateral half with the 595-nm PDL. For early intervention of the postoperative scar, the laser treatments were begun after 2 weeks from the Mohs micrographic surgery. RESULTS Both PDL and AFL produced statistically significant improvements. However, comparatively, there was no statistical difference between them. In each variable, AFL was more effective than PDL in the improvement of pliability and thickness. In contrast, PDL was superior to AFL in the improvement of vascularity and pigmentation. CONCLUSION Pulsed dye laser and AFL treatments for surgical scar provide significant improvement. Pulsed dye laser was more effective in color of scar compared with AFL, which showed marked improvement in the contour of scar. Overall improvement was not statistically different in the Vancouver Scar Scale.

Characteristics and Clinical Manifestations of Pigmented Purpuric Dermatosis

Background Pigmented purpuric dermatoses (PPD) are a spectrum of disorders characterized by a distinct purpuric rash. Although PPD can be easily diagnosed, the disease entity remains an enigma and a therapeutic challenge. Objective The purpose of this study was to investigate the characteristics and clinical manifestations of PPD and to elucidate the relationship between assumed etiologic factors and the clinical manifestations of PPD and treatment responses. Methods Retrograde analyses were performed to identify appropriate PPD patients who visited Korea University Medical Center Anam Hospital from 2002 to 2012. Results Information on 113 patients with PPD was analyzed, and 38 subjects with skin biopsy were included for this study. Schambergs disease was the most frequent clinical type (60.5%). Concomitant diseases included hypertension (15.8%), diabetes (10.5%), and others. Associated medication histories included statins (13.2%), beta blockers (10.5%), and others. Possibly associated etiologic factors were recent upper respiratory infection (5.3%), high orthostatic pressure due to prolonged standing (2.6%), and strenuous exercise (2.6%). A total of 36 patients (94.7%) were treated with one or more treatment methods, including oral antihistamines, pentoxifylline, topical steroids, and/or phototherapy. There was no significant difference in disease progress according to underlying diseases, medications, or association factors (p>0.05). Conclusion Our overall results were grossly consistent with the existing literature, excluding several findings. Although a possible relationship between PPD and cardiovascular disease or cardiovascular medication was proposed at the beginning of the study, no statistically significant correlations were found according to the specific clinical types and treatment responses (p>0.05).

A safety assessment of phototoxicity and sensitization of SiO2 nanoparticles

Despite widespread use of silicon dioxide (SiO2) NPs in industry and in our daily lives, no studies so far have evaluated the potential of their skin phototoxicity and sensitization. This study was designed to investigate the potential of phototoxicity and sensitization of SiO2 NPs. Assessment of the potential of skin phototoxicity was carried out using the 3T3 neutral red uptake test, an HSEM, and an animal model. The potential of skin sensitization was evaluated by a non-radioisotope local lymph node assay (non-RI LLNA). Findings from the present study suggest that the HSEM may be a reasonable model system for evaluation of skin phototoxicity of NPs. In addition, our data demonstrate that non-RI LLNA may be a useful method for identification of skin sensitization of NPs. In this study, we showed that SiO2 NPs do not induce phototoxicity or skin sensitization.

Retrospective analysis of melasma treatment using a dual mode of low-fluence Q-switched and long-pulse Nd:YAG laser vs. low-fluence Q-switched Nd:YAG laser monotherapy.

Abstract Background: Despite the effectiveness of low-fluence Q-switched Nd:YAG laser (QSNY) treatment in melasma, adverse events, including mottled hypopigmentation (MH) and rebound hyperpigmentation (RH) have been reported. Objective: To compare the effectiveness and safety of combination therapy using low-fluence QSNY and long-pulse Nd:YAG laser (LPNY) (Dual toning), with low-fluence QSNY monotherapy (QS toning), in Asian melasma patients. Materials and methods: Patients were treated for 10 sessions at 1-week intervals with QSNY (6 mm spot); 2.5–3.0 J/cm2 for QS toning (n = 177) or 2.1–2.5 J/cm2 for dual toning (n = 183). The dual toning group was immediately treated with LPNY (7 mm spot, 15–17 J/cm2). The results were evaluated using the modified Melasma Area and Severity Index (mMASI) score and the physicians global assessment. Results: MH or RH were significantly lower (1.1% vs. 14.1%) and the treatment efficacy was improved (median decrease of mMASI, 3.6 vs. 3.0) in the dual toning group compared with the QS toning group. Periorbital melasma showed distinctively high rates of adverse events in the QS toning group (23.9% vs. 5.7%), which were significantly reduced in the dual toning group (2.9%). Conclusion: Dual toning could represent a safe and effective treatment for Asian melasma patients, as it is associated with minimal adverse events and improved treatment efficacy compared with QS toning monotherapy.

Successful Treatment of Kimura's Disease with a 595-nm Ultra-Long Pulsed Dye Laser

Sir, Kimura’s disease (KD) is a rare, chronic inflammatory disorder that occurs predominantly in Asian males and is characterized by recurrent painless swellings involving the subcutaneous tissues, mainly in the head and neck region. It is also associated with eosinophilia and elevated levels of serum IgE. The histological features of KD are hyperplastic lymphoid tissue with well-developed lymphoid follicles, marked infiltration of eosinophils and vascular proliferation. Treatment is known to be difficult. We report here a case of KD that was treated successfully with an ultra-long pulsed dye laser (PDL).

Polycyclic Annular Lesion Masquerading as Lupus Erythematosus and Emerging as Tinea Faciei Incognito

Tinea incognito is a dermatophytic infection induced by immunosuppressive agents that lacks the classic features of a typical fungal infection. Although the treatment of tinea incognito is simple and relatively easy, its clinical manifestation varies and can masquerade as various skin disorders, causing misdiagnosis and thus preventing prompt and appropriate treatment. Here, we report an interesting case of tinea incognito occurring after topical steroid administration in an immunosuppressed patient with dermatitis artefacta. A 40-year-old female patient who had been taking systemic glucocorticoid for 4 years for chronic inflammatory demyelinating polyneuropathy presented with itching multiple erythematous erosive lesions on the face and upper chest for 2 months. Initial biopsy produced nonspecific findings. The skin lesion was aggravated and became polycyclic and erythematous; after azathioprine was added, her chronic inflammatory demyelinating polyneuropathy became aggravated. A second biopsy confirmed hyphae in the cornified layer. Complete remission was achieved after admonishing oral terbinafine and topical amorolfine.

Egr-1 is a key regulator of IL-17A-induced psoriasin upregulation in psoriasis

The early growth response (Egr)‐1 is a transcriptional factor which plays an important role in the regulation of cell growth, differentiation, cell survival and immune responses. Emerging evidences including our data demonstrate that the Egr‐1 expression is up‐regulated in the psoriatic skin lesions. The purpose of this study was to investigate the significance and regulatory mechanism of Egr‐1 in the pathogenesis of psoriasis. Through microarray analysis, we found out that psoriasin (S100A7) expression was increased in the Egr‐1 overexpressed cells. Our results showed that IL‐17A increased Egr‐1 expression in the skin of psoriatic patients and cultured human keratinocytes. We then investigated activation of mitogen‐activated protein kinase as an upstream signal regulator of Egr‐1 expression. IL‐17A‐induced Egr‐1 expression was suppressed by ERK inhibitor. In addition, IL‐17A induced psoriasin expression in cultured keratinocytes and the skin of IL‐17A intradermally injected mouse. IL‐17A‐mediated psoriasin upregulation was reduced after treatment of small interfering RNAs against Egr‐1. Furthermore, the results of chromatin immunoprecipitation assays demonstrated that Egr‐1 directly binds the psoriasin promoter. Our findings present a novel signalling mechanism by which IL‐17A can induce the Egr‐1‐dependent psoriasin expression via the ERK pathway in human keratinocytes. This study suggests that Egr‐1 may be a novel and important modulator in IL‐17A‐mediated immune response in psoriasis.