Melanin is a pigment produced from tyrosine in melanocytes. Although melanin has a protective role against UVB radiation-induced damage, it is also associated with the development of melanoma and darker skin tone. Tyrosinase is a key enzyme in melanin synthesis, which regulates the rate-limiting step during conversion of tyrosine into DOPA and dopaquinone. To develop effective RNA interference therapeutics, we designed a melanin siRNA pool by applying multiple prediction programs to reduce human tyrosinase levels. First, 272 siRNAs passed the target accessibility evaluation using the RNAxs program. Then we selected 34 siRNA sequences with ΔG ≥−34.6 kcal/mol, i-Score value ≥65, and siRNA scales score ≤30. siRNAs were designed as 19-bp RNA duplexes with an asymmetric 3′ overhang at the 3′ end of the antisense strand. We tested if these siRNAs effectively reduced tyrosinase gene expression using qRT-PCR and found that 17 siRNA sequences were more effective than commercially available siRNA. Three siRNAs further tested showed an effective visual color change in MNT-1 human cells without cytotoxic effects, indicating these sequences are anti-melanogenic. Our study revealed that human tyrosinase siRNAs could be efficiently designed using multiple prediction algorithms.
Dihydroxyphenylalanine ; Gene Expression ; Humans ; Melanins ; Melanocytes ; Melanoma ; Monophenol Monooxygenase* ; RNA ; RNA Interference ; RNA, Small Interfering* ; Skin Pigmentation ; Tyrosine ; Weights and Measures

PURPOSE: The purpose of this study was to assess the adhesiveness and cytotoxicity of 3, 4-dihydroxyphenylalanine (DOPA), and to evaluate the role of collagen membrane with DOPA in the guided bone regeneration. MATERIALS AND METHODS: Peel resistance and cell cytotoxicity test were performed. Four defect types in nine rabbit calvaria were randomly allocated: i) control, ii) membrane, iii) deproteinized porcine bone mineral (DPBM) covered by membrane with DOPA, and iv) DPBM covered by membrane with cyanoacrylate. Animals were sacrificed at 2 (n=4) and 8 weeks (n=5) for microcomputed tomography and histomorphometric analysis. DOPA showed low peel resistance but high cell viability. RESULT: Cyanoacrylate and DOPA groups showed significantly higher mineralized tissue volume (MTV) compared to control and membrane groups at 2 weeks (P < 0.05). At 8 weeks, DOPA group showed the highest MTV. Significantly higher new bone area was found in DOPA group at 8 weeks (P < 0.05). Bone formation increased from 2 to 8 weeks in DOPA group (P < 0.05). CONCLUSION: DOPA showed high cell viability and in vivo study revealed predictable performance in bone regeneration.
Adhesiveness ; Adhesives ; Animals ; Bone Regeneration ; Cell Survival ; Collagen ; Cyanoacrylates ; Dihydroxyphenylalanine ; Membranes ; Miners ; Osteogenesis ; Skull ; X-Ray Microtomography

The goal of this study was to determine whether gypenosides (GPS) exert protective effects against dopaminergic neuronal cell death in a 6-hydroxydopamine (OHDA)-lesioned rat model of Parkinson's disease (PD) with or without long-term 3,4-dihydroxyphenylalanine (L-DOPA) treatment. Rats were injected with 6-OHDA in the substantia nigra to induce PD-like symptoms; 14 days after injection, groups of 6-OHDA-lesioned animals were treated for 21 days with GPS (25 or 50 mg/kg) and/or L-DOPA (20 mg/kg). Dopaminergic neuronal cell death was assessed by counting tyrosine hydroxylase (TH)-immunopositive cells in the substantia nigra and measuring levels of dopamine, norepinephrine, 3,4-dihydroxyphenylacetic acid (DOPAC), and homovanillic acid (HVA) in the striatum. Dopaminergic neuronal cell death induced by 6-OHDA lesions was ameliorated by GPS treatment (50 mg/kg). L-DOPA treatment exacerbated 6-OHDA-induced dopaminergic neuronal cell death; however, these effects were partially reversed by GPS treatment (25 and 50 mg/kg). These results suggest that GPS treatment is protective against dopaminergic neuronal cell death in a 6-OHDA-lesioned rat model of PD with long-term L-DOPA treatment. Therefore, GPS may be useful as a phytotherapeutic agent for the treatment of PD.
3,4-Dihydroxyphenylacetic Acid ; Animals ; Cell Death* ; Dihydroxyphenylalanine ; Dopamine ; Dopaminergic Neurons* ; Homovanillic Acid ; Levodopa* ; Models, Animal* ; Norepinephrine ; Oxidopamine ; Parkinson Disease* ; Rats* ; Substantia Nigra ; Tyrosine 3-Monooxygenase

PURPOSE: The aim of this study was to evaluate the effect of immobilization of the recombinant human bone morphogenetic protein 2 (rhBMP-2) on anodized titaum implants coated with heparin to enhance the vertical alveolar ridge augmentation in the supraalveolar peri-implant defect region. MATERIALS AND METHODS: 18 pure titanium implants (7.0 mm in length, 3.5 mm in diameter) were manufactured for this study. All implants were anodized and designed insertion reference line marked with laser at the apical 2.5 mm from the fixture platform. Implantation of 6 noncoated anodized implants (Control group), 6 anodized implants physically adsorbed with rhBMP-2 by dip and dry method (BMP group) and 6 anodized implants chemically immobilized 3,4-dihydroxyphenylalanine (DOPA)-heparin/rhBMP-2 (Hep-BMP group) was performed in the both mandibular of three male adult beagle dogs using split-mouth design. Radiologic examinations were performed immediately after implant placement and 4 and 8 weeks after implant placement. The amount of mesio-distal bone augmentation was evaluated by measuring the vertical distance from the platform to the marginal bone. Statistical analysis was performed using one-way analysis of variance (SPSS version 18.0) and multiple comparison analysis of The Kruskal-Wallis test and the Mann-Whitney U test. Statistical significance was established at the 5%significant level. RESULTS: At the 4 weeks vertical alveolar ridge augmentation of Control group, BMP group and Hep-BMP group is 0.09 +/- 0.22 mm, 1.02 +/- 0.72 mm, and 1.29 +/- 0.51 mm, At the 8 weeks 0.11 +/- 1.26 mm, 1.11 +/- 0.58 mm, 1.59 +/- 0.79 mm according to radiographic observations. The two experimental groups showed a significantly increasing in vertical bone height compared with the control group (P<.05). However, there is no significant difference between the BMP group and Hep-BMP group (P>.05). CONCLUSION: The rhBMP-2 coated implants were enhanced the vertical bone growth in the supraalveolar peri-implant defect area. However, there is no significant difference between chemically and physically coating method.
Alveolar Process* ; Alveolar Ridge Augmentation* ; Animals ; Bone Development ; Bone Morphogenetic Protein 2* ; Bone Morphogenetic Proteins* ; Dihydroxyphenylalanine ; Dogs* ; Dopamine ; Heparin* ; Humans* ; Immobilization* ; Titanium

OBJECTIVE: Restless legs syndrome (RLS) has been reported to be more prevalent in schizophrenic patients who take antipsychotics. The cause of RLS is unknown but associated with dopaminergic deficiency. Tyrosine hydroxylase (TH) is the enzyme responsible for catalyzing the conversion of L-tyrosine to DOPA. The purpose of this study is to determine whether the TH gene Val81Met polymorphism is associated with antipsychotic-induced RLS. METHODS: One hundred ninety Korean schizophrenic patients were evaluated by the diagnostic criteria of the International RLS Study Group (IRLSSG). The genotyping was performed by PCR-based methods. RESULTS: Of the one hundred ninety schizophrenic patients, 44 (23.2%) were found to have RLS. Although there were no significant associations between TH genotypes or allele frequencies and RLS, when separate analyses were performed by sex (male or female), we detected significant differences in the frequencies of the genotype (chi-square=6.15, p=0.046) and allele (chi-square=4.67, p=0.031) of the TH gene Val81Met polymorphism between those with and without RLS in the female patients. CONCLUSION: These findings suggest that the TH gene Val81Met SNP might be associated with antipsychotic-induced RLS in female schizophrenic patients.
Alleles ; Antipsychotic Agents ; Dihydroxyphenylalanine ; Female ; Gene Frequency ; Genotype ; Humans ; Restless Legs Syndrome ; Schizophrenia ; Tyrosine ; Tyrosine 3-Monooxygenase

BACKGROUND: Tyrosinase is the critical enzyme in melanin synthesis. DOPA staining has been used as a standard assay for detecting tyrosinase activity, but it exhibits several limitations. Tyramide based tyrosinase assay (TTA) is a simple and sensitive tyrosinase detecting method. OBJECTIVE: This study aimed to compare the stainability of pigmentary disorders using TTA and DOPA staining. METHODS: The subjects were composed of hyperpigmentary disorders (n=10), hypopigmentary disorders (n=7), and alopecia areata (n=7). The colocalization study of TTA and Mitf using immunofluorescence was performed on alopecia areata. DOPA staining was performed on all tissues to compare with TTA immunohistochemistry. RESULTS: TTA positive cells were correlated with Mitf positive cells in the tissue of alopecia areata. In hyperpigmentary disoders, TTA was stronger than DOPA staining. TTA and DOPA staining didn't observe the positive cells in lesion of vitiligo and piebaldism, but both showed the positive cells in normal skin. TTA staining showed positive cells in the transitional lesion of vitiligo but, DOPA staining did not. In alopecia areata, TTA positive cells were observed, but DOPA staining did not. CONCLUSION: TTA is more sensitive than DOPA staining in pigmentary disorders for detecting tyrosinase activity.
Alopecia Areata ; Dihydroxyphenylalanine ; Fluorescent Antibody Technique ; Melanins ; Monophenol Monooxygenase ; Piebaldism ; Skin ; Vitiligo

BACKGROUND: Vitiligo is a depigmented disorder, causing serious cosmetic problems for patients. In diagnostic and therapeutic aspects, vitiligo should be differentiated from other hypopigmented disorders as the therapeutic approach and prognosis are different for each disease. OBJECTIVE: This study aimed to compare the usefulness of several markers for melanocytes or melanin in differential diagnosis of vitiligo. METHODS: Twenty-eight patients were studied, who were diagnosed clinically as suffering from one of the following diseases: vitiligo, nevus depigmentosus, pityriasis alba, postinflammatory hypopigmentation, and idiopathic guttate hypomelanosis. Skin samples (frozen or paraffin-fixed) were obtained from depigmented patches and normal neighboring skin (control). Histological staining was performed by using Fontana-Masson, S-100, MART-1, and DOPA. The staining level of lesional skin was compared with that of normal skin. RESULTS: When the staining level of vitiligo was compared with that of others, vitiligo was significantly lower in Fontana-Masson (13.3+/-17.2% vs 44.4+/-23.7%), S-100 (49.5+/-14.9% vs 74.7+/-24.2%), MART-1 (7.4+/-8.7% vs 68+/-33.9%), and DOPA (9.5+/-11.3% vs 58.2+/-29.5%) (p<0.0001). CONCLUSION: MART-1 and DOPA are valuable markers in differential diagnosis of vitiligo. However, Fontana-Masson, a marker of melanin, had some limits in detecting melanocytes, and S-100 showed non-specific staining other than melanocytes.
Cosmetics ; Diagnosis, Differential ; Dihydroxyphenylalanine ; Humans ; Hypopigmentation ; Melanins ; Melanocytes ; Nevus ; Pityriasis ; Prognosis ; Skin ; Stress, Psychological ; Vitiligo

OBJECTIVETo detect mutations of guanosine triphosphate cyclohydrolase I (GCH1) gene in Chinese patients with dopa responsive dystonia (DRD).

METHODSSix sporadic patients with DRD were examined. GCH1 gene mutations were detected using polymerase chain reaction (PCR), DNA sequence analysis and restriction enzyme digestion analysis. One hundred normal people were detected using PCR and restriction enzyme digestion analysis.

RESULTSA new point mutation, 151(G-->A) in exon one was found in a patient. It lead to substitution of a methionine for isoleucine at amino acid 1(M1I). This mutation was not found in normal control people.

CONCLUSIONThe authors report a new heterozygotic point mutation 151(G-->A) in GCH1 gene. There are GCH1 gene mutations in Chinese sporadic patients with DRD.

Asian Continental Ancestry Group ; genetics ; Case-Control Studies ; DNA ; genetics ; DNA Mutational Analysis ; Dihydroxyphenylalanine ; therapeutic use ; Dystonia ; drug therapy ; genetics ; Exons ; genetics ; Female ; GTP Cyclohydrolase ; genetics ; Humans ; Male ; Point Mutation ; genetics ; Polymerase Chain Reaction

We report a case of morphea occuring in vitiliginous lesions. About 5 months ago, two lesions of 4X4cm-sized depigmented patches appeared on her left thigh. The depigmented patches had begun to be hardened about 3 months ago. Histopathologic examinations showed that the reticular dermis appeared thickened, closely packed, hypocellular, and stained more deeply eosinophilic than in normal skin. The epidermis had no melanin pigments. Dopa stain was negative in white lesion, whereas Dopa stain was positive in normal lesion.
Dermis ; Dihydroxyphenylalanine ; Eosinophils ; Epidermis ; Melanins ; Scleroderma, Localized* ; Skin ; Thigh ; Vitiligo

Albinism is a hereditary disease caused by the defect of tyrosinase that converts tyrosine to dihydroxyphenylalanine (DOPA). `Oculocutaneous albinism' is classified as hypopigmentation of skin, hair and eyes, but incidences of `ocular albinism' where hypopigmentation is limited to eyes are found rarely. Biochemically, albinism is caused by the tyrosinase activity. Typical findings in oculocutaneous albinism include not only ophthalmologic problems such as hypopigmentation of skin, foveal hypoplasia, photophobia and decreased visual acuity but also congenital nystagmus. We cannot determine distinctive characteristics of nystagmus of albinism because domestically, there are only a few reports that have been recorded correctly about nystagmus of albinism. Merely, we present our experience of two cases of albinism with congenital nystagmus because we think that these two cases, showing different types of nystagmus and electronystagmography, stand for the two representative types of nystagmus found in the literature up to date.
Albinism ; Albinism, Oculocutaneous* ; Dihydroxyphenylalanine ; Electronystagmography ; Genetic Diseases, Inborn ; Hair ; Hypopigmentation ; Incidence ; Monophenol Monooxygenase ; Nystagmus, Congenital* ; Photophobia ; Skin ; Tyrosine ; Visual Acuity