Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Hypopigmentation”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7Linked to original sources
PubMed2006

Oral zinc sulphate causes murine hair hypopigmentation and is a potent inhibitor of eumelanogenesis in vivo.

BACKGROUND: C57BL/6 a/a mice have been widely used to study melanogenesis, including in electron paramagnetic resonance (EPR) studies. Zinc cations modulate melanogenesis, but the net effect of Zn2+ in vivo is unclear, as the reported effects of Zn2+ on melanogenesis are ambiguous: zinc inhibits tyrosinase and glutathione reductase in vitro, but also enhances the activity of dopachrome tautomerase (tyrosinase-related protein-2) and has agonistic effects on melanocortin receptor signalling. OBJECTIVES: To determine in a C57BL/6 a/a murine pilot study whether excess zinc ions inhibit, enhance or in any other way alter hair follicle melanogenesis in vivo, and to test the usefulness of EPR for this study. METHODS: ZnSO(4).7H2O was continuously administered orally to C57BL/6 a/a mice during spontaneous and depilation-induced hair follicle cycling (20 mg mL-1; in drinking water; mean+/-SD daily dose 1.2+/-0.53 mL), and hair pigmentation was examined macroscopically, by routine histology and by EPR. RESULTS: Oral zinc cations induced a bright brown lightening of new hair shafts produced during anagen, but without inducing an EPR-detectable switch from eumelanogenesis to phaeomelanogenesis. The total content of melanin in the skin and hair shafts during the subsequent telogen phase, i.e. after completion of a full hair cycle, was significantly reduced in Zn-treated mice (P=0.0005). Compared with controls, melanin granules in precortical hair matrix keratinocytes, hair bulb melanocytes and hair shafts of zinc-treated animals were reduced and poorly pigmented. Over the course of several hair cycles, lasting hair shaft depigmentation was seen during long-term exposure to high-dose oral Zn2+. CONCLUSIONS: High-dose oral Zn2+ is a potent downregulator of eumelanin content in murine hair shafts in vivo. The C57BL/6 mouse model offers an excellent tool for further dissecting the as yet unclear underlying molecular basis of this phenomenon, while EPR technology is well suited for the rapid, qualitative and quantitative monitoring of hair pigmentation changes.

Administration, Oral↗
PubMed1999

Hypopigmentation of a papillary carcinoma arising in a black thyroid.

We report a case of an unpigmented papillary carcinoma arising in a black thyroid induced by minocycline. Black thyroid syndrome is an unusual pigmented change seen almost exclusively in patients on minocycline, apparently resulting from an oxidative interaction between thyroid peroxidase and the drug. Twenty-six cases have previously been reported in the English literature, nine of which described an associated thyroid neoplasm. Four of these nine neoplasms were described as pale or hypopigmented. The nature of the lesion against the background of pigmentation suggests diminished function of the thyroid peroxidase in this clonal population.

Adult↗
PubMed2004

Neurofibromatosis I with unusual hypopigmentation masquerading as leprosy.

A case of Neurofibromatosis I (NFI) occurring in association with symmetrical peripheral nerve enlargement and multiple hypopigmented macules strikingly limited to the neurofibromas, with normal to minimally reduced sensations, evoking a strong clinical suspicion of co-existent lepromatous leprosy, is being reported. Leprosy was ruled out by microbiological, histopathological and electrophysiological studies. The case is interesting in view of the hypopigmented macules overlying the neurofibromas, which is an unreported feature of NFI.

Adult↗