Biomedical subjects

Kuo-Hsien Wang

Publications and source records attributed to Kuo-Hsien Wang.

5 recordsLinked to original sources

PubMed2006

Cosmetic applications of selected traditional Chinese herbal medicines.

Because tyrosinase catalyzes melanin synthesis, tyrosinase inhibitors are important in cosmetic skin-whitening. Oxidative stress contributes to skin aging and can adversely affect skin health, which means antioxidants active in skin cells may support skin health. We examined 25 traditional Chinese herbal medicines that might be useful for skin-whitening and skin health. Extracts (100microg/mL) were tested for cytotoxicity on human epidermal melanocytes (HEMn); 12 exhibited low cytotoxicity. Their effects on tyrosinase and melanin inhibitory activities and free radical scavenging activities were further assessed. Phenolic contents were evaluated using Folin-Ciocalteu reagent. Four herbs, Pharbitis nil, Sophora japonica, Spatholobus suberectus, and Morus alba, exhibited potent inhibitory effects on tyrosinase (IC(50) values 24.9, 95.6, 83.9, and 78.3microg/mL, respectively). Melanin inhibition was not dose-dependent. Sophora japonica (IC(50): 14.46microg/mL, 1,1-diphenyl-2-picrylhydrazyl (DPPH); 1.95microg/mL, hydroxyl radical) and Spatholobus suberectus (IC(50): 10.51microg/mL, DPPH; 4.36microg/mL, hydroxyl radical) showed good antioxidative activities and high phenolic contents (255 and 189mg of gallic acid/g extract, respectively). Among active anti-tyrosinase extracts, Sophora japonica and Spatholobus suberectus were especially potent in HEMn cells in terms of free radical scavenging effects and high phenolic contents, making them the strongest candidates for cosmetic application found in the current study.

Biphenyl Compounds↗

PubMed2005

HLA-B*5801 allele as a genetic marker for severe cutaneous adverse reactions caused by allopurinol.

Allopurinol, a commonly prescribed medication for gout and hyperuricemia, is a frequent cause of severe cutaneous adverse reactions (SCAR), which include the drug hypersensitivity syndrome, Stevens-Johnson syndrome, and toxic epidermal necrolysis. The adverse events are unpredictable and carry significant morbidity and mortality. To identify genetic markers for allopurinol-SCAR, we carried out a case-control association study. We enrolled 51 patients with allopurinol-SCAR and 228 control individuals (135 allopurinol-tolerant subjects and 93 healthy subjects from the general population), and genotyped for 823 SNPs in genes related to drug metabolism and immune response. The initial screen revealed strong association between allopurinol-SCAR and SNPs in the MHC region, including BAT3 (encoding HLA-B associated transcript 3), MSH5 (mutS homolog 5), and MICB (MHC class I polypeptide-related sequence B) (P < 10(-7)). We then determined the alleles of HLA loci A, B, C, and DRB1. The HLA-B*5801 allele was present in all (100%) 51 patients with allopurinol-SCAR, but only in 20 (15%) of 135 tolerant patients [odds ratio 580.3 (95% confidence interval, 34.4-9780.9); corrected P value = 4.7 x 10(-24)] and in 19 (20%) of 93 of healthy subjects [393.51 (23.23-6665.26); corrected P value = 8.1 x 10(-18)]. HLA alleles A*3303, Cw*0302, and DRB1*0301 were in linkage disequilibrium and formed an extended haplotype with HLA-B*5801. Our results indicated that allopurinol-SCAR is strongly associated with a genetic predisposition in Han Chinese. In particular, HLA-B*5801 allele is an important genetic risk factor for this life-threatening condition.

Aged↗

PubMed2004

Milium-like syringoma: a case study on histogenesis.

BACKGROUND: Milium-like syringoma is a variant of syringoma first described in 1987. Only few cases have been reported in the literature. It may be misleading clinically, and its histogenesis has not been clarified. CASE REPORT: We present a case of periorbital milium-like syringoma, with studies on the histopathologic, histochemical, and immunohistochemical features. RESULTS: Histology showed a large keratin-filled cyst in the upper portion of the lesion approximating the epidermis. Serial sections revealed that the cyst connected with the underlying syringomatous epithelial strands. Melanin was absent in the wall of the cyst, as demonstrated by Fontana-Masson stain. Cytokeratin 7 was expressed neither in the milia nor in the solid epithelial parts. Carcinoembryonic antigen (CEA) reactivity was seen in the luminal cells of the keratinous cysts. However, in the largest keratin-filled cyst clinically suggesting a milium, only the lower half of the cyst was positive for CEA. These results proved that the milia were part of syringoma with eccrine duct differentiation. Fusion of the upper half of the largest cyst with the epidermis may explain the absence of CEA positivity in this part, analogous with eccrine duct milia. Review of the literature indicated that this variant of syringoma occurs more often in Asians. CONCLUSION: We present evidence, and propose the histogenesis of milium-like syringoma, that it is a variant of syringoma with a prominent cystic component showing features of eccrine duct milia. Recognition of its nature is of therapeutic significance. Further studies are required to verify its clinical characteristics as compared with ordinary syringomas.

Adult↗

PubMed2004

Erbium:YAG laser pretreatment accelerates the response of Bowen's disease treated by topical 5-fluorouracil.

BACKGROUND: Topical 5-fluorouracil (5-FU) is a standard treatment for Bowen's disease. However, its efficacy may be limited by the presence of stratum corneum. The Er:YAG laser has shown a dramatic enhancement effect on the delivery of 5-FU in vitro by ablation of the stratum corneum. The efficacy of laser-assisted delivery of 5-FU has not been tested in human. OBJECTIVE: To see whether Er:YAG laser pretreatment can improve the efficacy of topical 5-FU in the treatment of Bowen's disease. METHODS: Three target lesions from a patient with multiple Bowen's disease were selected for a half-side comparison study. The Er:YAG laser was used to remove the cornified layer on one side of each lesion, followed by twice-daily application of 5-FU cream to both sides. Clinical and histologic responses were compared. RESULTS: Lesions pretreated with the Er:YAG laser showed more rapid clinical and histologic responses to topical 5-FU than those treated with 5-FU alone. Evaluation at 9 months after treatment showed no recurrences of lesions on both sides. CONCLUSIONS: Our preliminary study demonstrates that this Er:YAG laser-assisted modality is effective and shows accelerated clinical response and shortened treatment time compared with topical 5-FU as a single treatment.

Administration, Topical↗

PubMed2002

The effect of laser treatment on skin to enhance and control transdermal delivery of 5-fluorouracil.

The effect of three lasers (i.e., the ruby, erbium:YAG, and CO2) on the ability to enhance and control skin permeation of 5-fluorouracil (5-FU) was studied in vitro. Light microscopic and ultrastructural (scanning electron microscopic) changes in the nude mouse skin were also compared for these lasers. The histological observations and permeation profiles of each laser differed because the three lasers produce different physical and physiologic effects when striking the skin. The skin permeation of 5-FU could be moderately promoted by a single photomechanical wave generated by the ruby laser (at 4.0 and 7.0 J/cm(2)) without adversely affecting the viability or structure of the skin. The stratum corneum (SC) layer in the skin was partly ablated by an erbium:YAG laser, resulting in a greater enhancement effect on skin permeation of 5-FU. The flux of 5-FU across erbium:YAG laser-treated skin was 53-133-fold higher than that across intact skin. Both SC ablation and a thermal effect may contribute to the effect of the CO2 laser on skin structure. Lower energies of the CO2 laser did not modulate 5-FU permeation. A 36-41-fold increase in 5-FU flux was observed after exposure to higher fluences (4.0 and 7.0 J/cm(2)) of the CO2 laser. Histological changes induced by both the erbium:YAG and CO2 lasers had completely recovered within 4 days.

Administration, Cutaneous↗