A long-term time course of colorimetric assessment of the effects of imatinib mesylate on skin pigmentation: a study of five patients

BACKGROUND: Imatinib mesylate (IM), the first-line treatment of chronic myeloid leukaemia (CML), is a tyrosine kinase inhibitor that targets those proteins involved in BCR-ABL signal transduction in CML, c-kit (KIT) and platelet-derived growth-factor (PDGFR) receptor. The use of IM has been associated with cutaneous reactions. In the last 2 years numerous studies have focused the attention on hypopigmentations, depigmentations and photosensitivity developing after the initiation of IM therapy. OBJECTIVE: The aim of this study is to evaluate the effects of IM therapy on the skin pigmentation of five patients affected by CML. METHODS: Skin pigmentation measurements were performed with a Minolta CR-200 Chromameter. results: All the studied patients show the gradual lightening of the skin on unexposed areas over the treatment with IM. In particular, this explorative colorimetric study indicates the association between IM and skin depigmentation with a significant increase of luminance value (L*) (P = 0.001) and a significant decrease of the pigmentation value (b*) (P = 0.028). CONCLUSION: Even if we do not know the clinical significance of the skin depigmentation caused by IM, the regulatory role of KIT and its ligand stem cell factor in melanocyte development and survival seems to suggest an objective mechanism of action for IM in the pathogenesis of this cutaneous depigmentation.     

Adolescence Mycosis Fungoides: An Unusual Presentation with Hypopigmentation

Mycosis fungoides (M.F.) is a rare cutaneous malignancy of childhood and adolescence. The disease commonly presents with the classic sequence of erythematous patches and plaques. Hypopigmentation as the presenting symptom is distinctly rare. This is the 9th case report of M.F. presenting with hypopigmentation in a patient under 20 years of age. The disease was only partially controlled with PUVA therapy, necessitating nitrogen mustard treatment.     

Genomic imprinting and uniparental disomy in Angelman and Prader-Willi syndromes: A review

Although Angelman (AS) and Prader-Willi (PWS) syndromes are human genetic disorders with distinctly different developmental and neurobehavioural phenotypes, they both have abnormalities in inheritance of chromosome 15q11–q13. Whether AS or PWS arises depends on the parental origin of a deletion or uniparental disomy (the inheritance of 2 copies of a genetic locus from only one parent) for 15q11–q13. Normal development requires a genetic contribution for this genetic region from both a male and female parent. The dependence on parental origin implies that genes in human 15q11–q13 have distinct functions depending upon epigenetic, parent-of-origin differences, known as genomic imprinting. Here, I review the role of uniparental disomy and genomic imprinting in the pathogenesis of AS and PWS, and briefly discuss phenotype-genotype correlations using candidate genes and mouse models, in particular for hypopigmentation. © 1993 Wiley-Liss, Inc.     

进行性斑状色素减少症发病机制初步探讨

目的探讨进行性斑状色素减少症(progressive macular hypomelanosis,PMH)患者皮损中分离出的痤疮丙酸杆菌对人角质形成细胞(human keratinocytes,HaCaT)细胞分泌干扰素(interferon,IFN)-γ、白细胞介素(interleukin,IL)-6、肿瘤坏死因子(tumor necrosis factor,TNF)-α的影响。方法体外培养HaCaT细胞株,分别加入分离自PMH的痤疮丙酸杆菌、痤疮丙酸杆菌标准菌株(NCTC737),酶联免疫吸附试验(enzyme-linked immunosorbent assay,ELISA)方法测定细胞上清液中IFN-γ、IL-6、TNF-α的分泌量。结果 PMH患者中分离的痤疮丙酸杆菌与角质形成细胞HaCaT细胞株共培养后,能促进角质形成细胞分泌IFN-γ和IL-6,与空白组比较,有明显升高,差异有统计学意义(P0.05);与痤疮丙酸杆菌标准菌株NCTC737相比也升高,差异有统计学意义(P0.05)。结论进行性斑状色素减少症皮损中分离出的痤疮丙酸杆菌可刺激HaCaT细胞分泌IFN-γ、IL-6、TNF-α,提示可能是皮损色素减退的原因之一。     

Q开关1064 nm Nd:YAG激光治疗黄褐斑所致点状色素减退:2年随访研究

目的:了解大光斑低能量模式Q开关1064 nm激光治疗黄褐斑后所致点状色素减退恢复情况。方法:对大光斑低能量模式Q开关1064 nm Nd:YAG激光治疗5次以上的180例黄褐斑患者随访2年。结果:15例出现点状色素减退(8.33%),2年后1例痊愈,2例有改善,13例无变化。结论:大光斑低能量Q开关1064 nm激光治疗黄褐斑所致的点状色素减退斑可持续2年以上。     

Hypopigmentation from UV resin additive

An employee formulating a UV-resin based vehicle developed hypopigmentation limited to the forearms without preceding overt dermatitis. Manual procedures in an automatic process provided opportunity for exposure and contact to various components. A non-resin additive, quinone, alone or in conjunction with a likely contaminant, hydroquinone, was the suspected agent. Patch tests to quinone caused severe irritation. Reactions to acrylic components were not felt to be directly pertinent.     

Management of dyschromias in ethnic skin

Pigmentary disorders are one of the most common skin disorders among people of color. Dyspigmentation in the form of either hyperpigmentation or hypopigmentation is often psychologically devastating to patients with darker skin. There is marked contrast between normally pigmented hyperpigmented, hypopigmented or depigmented skin in people of color. Despite being common, pigmentary disorders remain difficult to treat.     

Lipoperoxidase activity of Pityrosporum: characterisation of by-products and possible rôle in pityriasis versicolor

Abstract Modification of pigmentation and damage of melanocytes are characteristic features of skin colonisation by Pityrosporum orbiculare hyphae in pityriasis versicolor (PV). The yeast is lipophylic and lipid-dependent, capable of oxidising unsaturated lipid components of skin surface, i.e. unsaturated fatty acids, cholesterol and squalene (SQ). The oxidation of unsaturated fatty acids gives rise to dicarboxylic acids (DA) which behave, in vitro, as competitive inhibitors of tyrosinase. In this work, we further investigate the oxidase activity of Pityrosporum in vitro, by evaluating (a) the generation of lipoperoxides in cultures supplemented with fatty acids at various degrees of unsaturation; (b) the mechanism of SQ oxidation; (c) the chemical characteristics of some by-products of lipoperoxidation; (d) the formation of peroxisomes in fungal cells. In cultures supplemented with the saturated palmitic acid (C16:0) and monounsaturated oleic acid (C18:1 n-9), low amounts of lipoperoxides were detected by a spectrophotometric test, whereas in cultures supplemented with di-unsaturated linoleic acid (C 18:2 n-6), significant concentrations were found. Gas chromatographymass spectrometry analyses showed the generation of linoleic acid hydroperoxides both in Pityrosporum cultures and following incubation of acetone powder of the fungus with the unsaturated fatty acid, indicating the presence of a lipoxygenase activity in the fungus. In cultures supplemented with linoleic acid plus SQ, and increase of lipoperoxide generation was observed and trans-trans farnesal and squalene epoxides have been identified. Electron microscopic examinations have evidenced peroxisomes in cells grown in the presence of linoleic acid, whereas they were not delected in cultures supplemented with oleic acid and palmitic acid. The metabolic activities of peroxisomes, through the formation of hydrogen peroxide and the subsequent generation of hydroxyl radicals, may account for the peroxidation of SQ, which is not a substrate of lipoxygenase. Following these results, we propose a mechanism for DA generation by Pityrosporum metabolism and hypothesize that the lipoperoxidation process induced by lipoxygenase activity of the fungus may be the key to understanding the clinical appearance of skin manifestation of PV.