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Black Pigmentation (black + pigmentation)
Selected AbstractsTetracycline/doxycycline-induced cutaneous depressed pigmentationINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 10 2006Esra Adisen MD Pigmentary disorders are recognized adverse effects of tetracyclines. Unlike minocycline, which occasionally causes black pigmentation of a variety of tissues, tetracycline itself or doxycycline is rarely attributed to the pigmentation of skin. Herein, we report the first case report of blue-black discoloration developed within depressed acne scars following tetracycline/doxycycline therapy for acne. [source] The endocrine control of phase transition: some new aspectsPHYSIOLOGICAL ENTOMOLOGY, Issue 1 2003Michael Breuer Abstract. The present article summarizes some recent findings relating to the underlying mechanism of phase transition in locusts, from the nonswarming solitarious phase to the swarming gregarious phase. These phases differ in many traits, such as colouration, morphometrics and behaviour. The most comprehensive theory at present to explain the switch from the nonswarming to the swarming form is that the locusts are brought together by the heterogeneity of the environment. They gather at preferential structures and food plants and physical contact then stimulates individuals to gregarize. Phase change can also be transferred across generations by maternal pheromones. The endocrine regulation of phase polymorphism is still not fully understood. The role of ecdysteroids has been studied, so far with no final conclusion. It is remarkable that the prothoracic glands persist longer in isolated-reared adults, which implies that these glands continue to play a role, although they no longer release important amounts of ecdysteroids. Juvenile Hormone, without any doubt, induces certain solitarious characteristics, such as green colouration, but is not the primary causal factor. A real breakthrough was the discovery of [His7]-corazonin, made possible by using a novel assay system, the Okinawa albino mutant of Locusta migratoria, which was known to be deficient in this hormone. This peptide, which is produced in the brain and is most likely released via the corpora cardiaca, promotes the gregarious black pigmentation. It also plays a role in morphometrical phase change as well as in behavioural alterations. Corazonin is apparently quite an important peptide not only in locusts, but also in insects in general. [source] Two cases of subungual melanoma in situTHE JOURNAL OF DERMATOLOGY, Issue 11 2008Sumihisa IMAKADO ABSTRACT Melanonychia, which is characterized by brown or black pigmentation within the nail plate, includes heterogeneous conditions such as pigmented nevus, subungual melanoma and lentigo. We treated two cases of subungual melanoma in situ. One case was a 58-year-old woman who suffered from a malignant melanoma in situ of the left third fingernail, who had also suffered from melanonychia of the fingers for more than 30 years. She had a past history of carcinoma of the uterine cervix. The other patient was a 42-year-old man, who suffered from a malignant melanoma in situ of the right fifth fingernail. He had a past history of carcinoma of the stomach for which he had undergone surgery 2 years earlier. Both cases were accompanied by Hutchinson's sign on the fingertip skin, and the presence of this sign led to the correct diagnosis of subungual melanoma in situ. Judging from previously reported cases, it is unlikely that patients with malignant melanoma have an increased risk of carcinoma of the uterine cervix or of the stomach. [source] A new type of minocycline-induced cutaneous hyperpigmentationCLINICAL & EXPERIMENTAL DERMATOLOGY, Issue 1 2004R. W. Mouton Summary Pigmentary disorders are recognized adverse effects of the semi-synthetic tetracycline derivative antibiotic, minocycline. Three distinct types of minocycline-induced cutaneous pigmentation have been described. Type I, blue,black pigmentation confined to sites of scarring or inflammation on the face; Type II, blue,grey circumscribed pigmentation of normal skin of the lower legs and forearms; and Type III, diffuse muddy brown pigmentation of normal skin accentuated in sun-exposed areas. We report two patients with acne vulgaris with a fourth type of minocycline-induced cutaneous pigmentation. They presented with circumscribed blue,grey pigmentation within acne scars confined to the back. Histology showed pigment within dendritic cells, and extracellularly throughout the dermis. Histochemistry identified a calcium containing melanin-like substance. Iron was absent. Immunohistochemistry confirmed some pigment-containing cells to be macrophages. Electron microscopy demonstrated electron-dense granules, free and membrane-bound, within macrophages and fibroblast-like cells. Energy-dispersive X-ray analysis confirmed the presence of calcium. Iron was absent. This fourth type of cutaneous minocycline hyperpigmentation may be a variant of Type I, but based on clinical, pathological and microanalytical differences, appears to be a new entity. The pigment may be a drug metabolite,protein complex chelated with calcium, or an insoluble minocycline,melanin complex. We propose a classification of cutaneous minocycline pigmentation based on clinico-pathological criteria. [source] | ||||||||||