Sungkoo Lee

Protective role of nitric oxide-mediated inflammatory response against lipid peroxidation in ultraviolet B-irradiated skin

Ultraviolet (UV) irradiation is known to induce serious oxidative damage in the skin via lipid peroxidation. Nitric oxide (NO) synthesized by keratinocytes, melanocytes and endothelial cells in response to proinflammatory cytokines and UV radiation, has been reported to prevent UV‐induced apoptosis in the skin. We have examined the effects of NO on UVB‐induced lipid peroxidation in murine skin in vivo. UVB induced a dose‐dependent increase in lipid peroxidation of skin extracts in vitro; however, lipid peroxidation in the skin in vivo remained unaffected at irradiation doses of less than 1·0 J cm−2 and decreased significantly at doses over 1·5 J cm−2 (P < 0·01). Time‐delayed inhibition of lipid peroxidation in the skin in vivo was observed after irradiation at 1·5 J cm−2. Administration of N G‐nitro‐ l‐arginine methyl ester ( L‐NAME), an inhibitor of NO synthesis, enhanced lipid peroxidation (P < 0·05), while it suppressed the ear‐swelling response (ESR), a biological marker of inflammation. By contrast, administration of sodium nitroprusside, an NO enhancer, suppressed lipid peroxidation (P < 0·01), while it enhanced the ESR. Expression of inducible nitric oxide synthase (iNOS) was observed from 12 to 48 h postirradiation at doses of 0·4–1·6 J cm−2. The UVB‐induced iNOS expression was markedly inhibited by L‐NAME, suggesting that iNOS is a major enzyme in the production of NO. These results suggest that NO acts as a mediator of the inflammatory response in UVB‐irradiated skin, and that lipid peroxidation is inversely regulated with the NO‐mediated inflammatory response in vivo.

Relationship of protoporphyrin IX synthesis to photodynamic effects by 5-aminolaevulinic acid and its esters on various cell lines derived from the skin

Background  5‐Aminolaevulinic acid (ALA) and its esters act as precursors to the fluorescent photosensitizer protoporphyrin IX (PpIX) in photodynamic therapy (PDT). There is little information about how ALA and its esters induce PpIX synthesis and photodynamic effects in cell lines derived from the skin.

Photodetection of basal cell carcinoma using methyl 5‐aminolaevulinate‐induced protoporphyrin IX based on fluorescence image analysis

Background.  The preferential accumulation of 5‐aminolaevulinic acid (ALA)‐induced protoporphyrin IX (PpIX) in neoplastic cells supports its potential use in the photodetection of porphyrin fluorescence in tumour cells. Hence, epithelial tumours, including basal cell carcinoma (BCC), might be visualized using the fluorescence of selectively accumulated ALA‐induced PpIX.

Paraneoplastic pemphigus without an underlying neoplasm

We describe a 52‐year‐old man with paraneoplastic pemphigus (PNP) without any evidence of an underlying neoplasm over an 8‐year follow‐up period. He had a chronic relapsing vesiculobullous eruption for approximately 7 years (from April 1998 to May 2005). Initially, scattered flaccid vesicles with crusts developed on the face and trunk, which waxed and waned several times. Our patient was diagnosed as having PNP based on immunopathological criteria for PNP, i.e. histopathological, immunoblotting and immunoprecipitation analyses. However, physical and laboratory examinations including serial blood tests with peripheral blood smear, whole‐body positron emission tomography/computed tomography and abdominal ultrasound were unable to detect any underlying neoplasm over an 8‐year follow‐up period.

Growth of ZnO Nanorod Arrays on Flexible Substrates: Effect of Precursor Solution Concentration

We report a low-temperature aqueous solution growth of uniformly aligned ZnO nanorod arrays on flexible substrates. The substrate is Indium Tin Oxide (ITO) film coated on polyethylene terephthalate (PET). Solutions with five different concentrations of the precursors with equimolar Zinc Nitrate and Hexamethylenetetramine (HMT) in distilled water were prepared to systematically study the effect of precursor solution concentration on the structural and optical properties of ZnO nanorods. It was concluded that the precursor concentration have great influence on the morphology, crystal quality, and optical property of ZnO nanorods. The diameter, density, and orientation of the nanorods are dependent on the precursor solution concentration. X-ray diffraction and micro-Raman spectroscopy showed that the ZnO nanorods with the highest concentration of 50 mM were highly aligned and have the highest level of surface coverage. It was also found that the diameter and length of the nanorods increases upon increasing precursor solution concentration. This is the first systematic investigation of studying the effect of precursor solution concentration on the quality of ZnO nanorods grown on ITO/PET substrates by low-temperature solution method. We believe that our work will contribute to the realization of flexible organic-inorganic hybrid solar cell based on ZnO nanorods and conjugated polymer.

Two cases of clear cell sarcoma with different clinical and genetic features: cutaneous type with BRAF mutation and subcutaneous type with KIT mutation

Clear cell sarcoma (CCS), also known as malignant melanoma of soft parts, is a rare malignancy constituting approximately 1% of all soft‐tissue sarcomas. It occurs predominantly in the lower extremities of young adults, manifesting as a deep, painless, slow‐growing mass. CCS is sometimes confused with other types of melanoma because of its melanocytic differentiation. Although BRAF and KIT mutations are well‐known melanocytic tumour‐promoting mutations frequently found in cutaneous melanoma, they are rare or absent in CCS. We present two cases of CCS with different clinical and genetic features. Both female patients, aged 25 and 20 years, presented with a palpable nodule on a lower extremity. Biopsies of both tumours revealed features diagnostic of CCS. Each tumour cell was positive for S100 protein and HMB‐45. However, one patients tumour was localized to the dermis, with many multinucleated giant cells, whereas the other was located in the deep subcutaneous fat layer near bone. Fluorescence in situ hybridization demonstrated the presence of a characteristic Ewing sarcoma RNA‐binding protein (EWSR)1 gene rearrangement in both cases. Reverse‐transcription polymerase chain reaction (PCR) and sequencing of the PCR product revealed an EWSR1–activating transcription factor 1 type 1 fusion transcript in both cases. In addition, we detected BRAF mutation in the dermal type and KIT mutation in the subcutaneous type. It is of interest that the BRAF and KIT mutations are known to be very rare in CCS. On the basis of our observations, we suggest that mutation inhibitors may be useful in selected patients with mutated CCS lineages.

Reduction of Electrical Hysteresis in Cyclically Bent Organic Field Effect Transistors by Incorporating Multistack Hybrid Gate Dielectrics

We have fabricated flexible organic field effect transistors (OFETs) on polyimide substrate with low hysteresis and low leakage current under repetitive bending. The insertion of an ultrathin atomic-layer-deposited Al 2 O 3 layer in between spin-coated poly-4-vinyl phenol organic layers in a multistack hybrid gate dielectric for OFETs significantly improved stability in the electrical hysteresis during cyclic bending. The observed hysteresis stability for cyclically bent multistack hybrid OFET devices was attributed to efficient blocking of charges injected from the gate electrode due to improved mechanical stability. Cyclically bent samples showed no cracking for thinner Al 2 O 3 layers in the multistack hybrid gate dielectrics.

Pemphigus foliaceus induced by an angiotensin II receptor blocker

A 76‐year‐old Korean woman presented with pruritic erythematous vesicles and crusted plaques over her entire body. She had been taking an angiotensin II receptor blocker (ARB) (candesartan) for 2 months before developing the skin lesions. The patients was diagnosed with pemphigus foliaceus based on the clinical and immunopathological criteria, including intra‐epidermal bulla on skin histopathology, intercellular deposit of C3 and IgG on direct immunofluorescence, and autoantibodies to the 160‐kDa antigen on both immunoblot and ELISA. The medication was changed to another antihypertensive agent and the patient was treated with prednisolone for 2 months. The vesiculobullous skin lesions gradually disappeared. However, the skin lesions reappeared 2 months after starting a different ARB (telmisartan). This case illustrates the importance of taking a complete drug history in patients who present with bullous diseases. Furthermore, ARBs should be added to the list of nonthiol drugs that can possibly induce pemphigus.

A case of porphyria cutanea tarda in association with idiopathic myelofibrosis and CREST syndrome

We report a 56‐year‐old Korean woman with porphyria cutanea tarda (PCT), showing multiple scarring bullae and hypertrichosis on sun‐exposed areas of skin with postinflammatory hyperpigmentation. Sclerodermoid changes were also found on both hands, the face and neck. The patient had suffered from CREST syndrome, manifesting with Raynaud’s phenomenon and sclerodactyly, for more than 15 years. Anticentromere antibody was positive. She had presented with splenomegaly 3 years before the development of PCT, and was diagnosed as having idiopathic myelofibrosis, based on bone marrow biopsy. In summary, she had had CREST syndrome for 15 years and later developed idiopathic myelofibrosis and PCT. This is the first reported case of PCT in association with idiopathic myelofibrosis and CREST syndrome.

Cutaneous abscess by Trichosporon asahii developing on a steroid injection site in a healthy adult

We report a rare case of cutaneous abscess by Trichosporon asahii in an immunocompetent adult. A 31‐year‐old Korean woman presented to our hospital with a cutaneous abscess. She had received an intralesional steroid injection 4 months earlier on the site of a hypertrophic scar. Direct sequencing of the intergenic spacer regions of the rRNA genes identified T. asahii. The decreased local immunity after the steroid injection might have triggered the infection by T. asahii. A cutaneous abscess formation by T. asahii in an immunocompetent patient is an unusual cutaneous finding that to our knowledge has not been reported previously. The local immune reaction of the skin is important for the prevention of Trichosporon infection.