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Melanin Granules (melanin + granule)
Selected AbstractsErythema dyschromicum perstans and hepatitis C virus infectionINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 5 2001George J. Kontochristopoulos MD A 48-year-old woman with a 10-month history of widespread, hyperpigmented, slightly pruritic macules, with a red border, involving the trunk and the proximal limbs (Fig. 1) was referred to our outpatient department. The oral mucosa, palms, soles, scalp, and nails were normal. Figure 1. Multiple hyperpigmented macules with an active border on the trunk Laboratory tests showed elevated liver enzymes [alanine aminotransferase (ALT), 68 IU/L (normal value, <,40 IU/L); aspartate aminotransferase (AST), 41 IU/L (normal value, <,40 IU/L)], the presence of antibodies to hepatitis C virus (anti-HCV) and HCV RNA (Amplicor Roche). In addition, cryoglobulinemia type III (IgM,,,, IgG,,,) was detected with a high cryocrit value, and there was detectable C-reactive protein, rheumatoid factor, and a low titer of antinuclear antibodies (1 : 80). A percutaneous liver biopsy showed changes compatible with mild chronic hepatitis (grade, 6; stage, 0). The possible source of infection was unknown, as the patient had no history of parenteral transmission (e.g. blood transfusions, intravenous illicit drug use). A skin biopsy specimen from the active border of a lesion showed hyperkeratosis, parakeratosis, and hydropic degeneration of the basal cell layer, with the formation of colloid bodies in the epidermis. A moderate perivascular lymphohistiocytic infiltrate with melanophages and free melanin granules was observed in the upper dermis (Fig. 2). Immunostaining of paraffin-embedded tissue sections with the TORDJT-22 IgG1 mouse monoclonal antibody to HCV (Biogenex, Son Ramon, USA), which is specific for the nonstructural region of HCV (NS3-NSH, C100 antigen) using the avidin,biotin,peroxidase complex (ABC) as well as the alkaline phosphatase antialkaline phosphatase (APAAP) methods, failed to detect HCV in the lesion of erythema dyschromicum perstans (EDP) (Nakopoulou L, Manolaki N, Lazaris A et al. Tissue immunodetection of C100 hepatitis C virus antigen in major thalassemic patients. Hepato-Gastroenterol 1999; 46: 2515,2520). Direct immunofluorescence showed IgG, IgM, IgA, and fibrinogen deposits on colloid bodies. EDP was diagnosed on the basis of these clinical and laboratory findings. Figure 2. Hydropic degeneration of the basal cell layer with colloid bodies in the epidermis. Moderate perivascular lymphohistiocytic infiltrate with melanophages and free melanin granules in the upper dermis (hematoxylin and eosin, ×,200) The patient was treated with interferon-,2b (Intron-A, Schering Plough Athens, Greece), 3 MU thrice weekly subcutaneously for 12 months, with additional topical steroid application. There was no response to this treatment with new lesions appearing in previously unaffected areas of the trunk and extremities. HCV RNA remained persistently positive. Thus, a modified regimen with interferon-,2b, 6 MU thrice weekly for 6 months, was tried. At the end of the treatment course, the eruption of EDP had greatly improved. Liver enzymes were normal (ALT, 22 IU/L; AST, 24 IU/L) and HCV RNA had become negative. Four months later, however, cutaneous lesions reappeared and hepatitis C relapsed. At this time point, combination therapy of interferon-,2b, 3 MU thrice weekly, with ribavirin, 1000 mg daily, was given. Six months later, liver enzymes were normal (ALT, 42 IU/L; AST, 39 IU/L), HCV RNA was negative, and the lesions of EDP had resolved. [source] Chloracne: histopathologic findings in one caseJOURNAL OF CUTANEOUS PATHOLOGY, Issue 4 2002Maria Antonia Pastor Background: Chloracne is an acneiform eruption due to poisoning by halogenated aromatic compounds having a specific molecular shape. This condition is always a symptom of systemic poisoning by chemical chloracnegens and not just a cutaneous disorder. Methods: We have studied a patient with severe chloracne who showed cutaneous lesions involving mostly the face and the axillae. Results:, Histopathologic study of the facial lesions demonstrated that almost every vellus hair follicle was involved, showing a dilated infundibulum filled by a keratotic plug. This keratotic material was mostly composed of orthokeratotic basket-weave basophilic corneocytes, namely infundibular keratin, although there were also some dilated infundibula containing eosinophilic laminated or granular sebum at their center. Small infundibular cysts were more numerous than comedones. Mature and well-developed sebaceous glands were seen at the base of many of the dilated infundibula and no squamous metaplasia of the sebaceous glands or ducts could be demonstrated. Hyperpigmentation of the lesions resulted from hyperproduction of melanin by a normal number of melanocytes along the basal layer of the epidermis and infundibular epithelium. Abundant melanin granules also impregnated the corneocytes of the infundibular plugs. Conclusions:, Our findings support the notion that tiny infundibular cysts rather than comedones represent the basic lesions of chloracne. [source] Structure of the skin of an air-breathing mudskipper, Periophthalmus magnuspinnatusJOURNAL OF FISH BIOLOGY, Issue 6 2002J. Y. Park The epidermis of the mudskipper Periophthalmus magnuspinnatus consisted of three layers: the outermost layer, middle layer and stratum germinativum. Extensive vascular capillary networks were present near the superficial layer of epidermis and outermost layer. The diffusion distance between the vascular capillaries and the surface of epidermis was c. 1.5 ± 0.9,m. The middle layer consisted of small or voluminous cells swollen by epidermal cells. Due to the swollen cells, the thickness of the epidermis increased and the epidermis appeared web-like. The swollen cells contained tonofilaments, lucent contents and desmosomes. Fine blood capillaries were also discernible in this layer. Well-developed lymphatic spaces containing lymphocytes existed in the stratum germinativum. Numerous blood capillaries were present under the basement membrane. The dermis consisted of a stratum laxum and stratum compactum, and there was a definite area with acid mucopolysaccharides and a small scale in the stratum laxum. The skin had an epidermal pigment cell, dendritic melanophores (-cytes) containing melanin granules within their cytoplasm, and two kinds of dermal pigment cells, melanophores and colourless pigments containing reflecting platelets. [source] Cytomorphological alterations of the thymus, spleen, head-kidney, and liver in cardinal fish (Apogonidae, Teleostei) as bioindicators of stressJOURNAL OF MORPHOLOGY, Issue 1 2006Lev Fishelson Abstract Morphological and cytological alterations at the light microscope (LM) and transmission electron microscope (TEM) levels were observed in the thymus, spleen, head-kidney, and liver of cardinal fishes (Apogonidae, Teleostei) from the Gulf of Aqaba, Red Sea, sampled from a strongly polluted site at the northern end of the gulf, and compared to similar samples from a clean, reference site. At the polluted site, the most prominent change was the formation of numerous deposits of cells rich in phagosomes with lipofucin, melanin granules, and phagocytosed debris, including a high increase in number and dimensions of Hassall's corpuscles and melano-macrophage centers. The number of Hassall's corpuscles was 20 (±8.0)/mm2 and of melano-macrophage centers 18 (±4.0)/mm2 at the polluted site, and 7.0 (±4.0)/m2 vs. 5.0 (±2.0)/mm2 respectively at the reference site. In numerous instances the head kidney's melano-macrophage centers in fishes from the polluted site were encapsulated by reticulocytes, a phenomenon recognized as a marker of neoplasmosis and possible malignancy. In the spleens of fishes from the polluted site, numerous deposits of cell debris, peroxisomes, and enlarged lysosomes were also observed. The livers (hepatopancreas) of fishes from polluted waters demonstrated very strong hyperlipogeny. Many of their hepatocytes were laden with lipid vesicles, fragmented endoplasmic reticulula, and aberrant mitochondria. Although the observed alterations in the glands and liver do not indicate any immediate threat to the life of the fish, they can become crucial with respect to energy turnover and fecundity trajectories. This study strongly suggests the use of cytological alterations in vital organs, such as were observed, as pathological biomarkers to environmental stress. J. Morphol. © 2005 Wiley-Liss, Inc. [source] French Maritime Pine Bark (Pinus maritima Lam.) Extract (Flavangenol®) Prevents Chronic UVB Radiation-induced Skin Damage and Carcinogenesis in Melanin-possessing Hairless MicePHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 4 2010Yoshiyuki Kimura A French maritime pine bark extract, Flavangenol®, is widely used as a nutritional supplement for protection against atherosclerosis, hypertension, diabetes, etc. Chronic exposure to solar UV radiation damages skin, increasing cutaneous thickness, wrinkling and pigmentation, as well as reducing elasticity, and causes skin cancer. The aim of this study was to examine the effects of flavangenol on skin damage and the incidence of skin tumors caused by long-term UVB irradiation in melanin-possessing hairless mice. The oral administration of flavangenol (60, 200 or 600 mg kg,1, twice daily) significantly inhibited increases in skin thickness, and the formation of wrinkles and melanin granules, as well as increases in the diameter and length of skin blood vessels. Furthermore, it prevented increases in numbers of apoptotic, Ki-67-positive and 8-hydroxy-2,-deoxyguanosine (8-OHdG)-positive cells, and the expression of skin vascular endothelial growth factor (VEGF) induced by chronic UVB irradiation. The effect on these biomarkers was associated with a reduction in the incidence of tumors in mice. The antiphotoaging and anticarcinogenetic activities of flavangenol may be due to inhibition of the expression of Ki-67, 8-OHdG and VEGF through a scavenging effect on reactive oxygen species. [source] Dopamine melanin-loaded PC12 cells: a model for studies on pigmented neuronsPIGMENT CELL & MELANOMA RESEARCH, Issue 4 2005Anna Östergren Summary The most conspicuous feature in idiopathic parkinsonism is the degeneration of pigmented neurons in the substantia nigra. A major problem for the study of the significance of neuromelanin for the development of parkinsonism is that common experimental animals lack neuromelanin in substantia nigra. The aim of this study was to develop an in vitro model that could be used to study the role of neuromelanin in chemically induced toxicity in dopaminergic cells. Cultured neuron-like PC12 cells were exposed to synthetic dopamine melanin (0,1.0 mg/ml) for 48 h, resulting in uptake of dopamine melanin particles into the cells. The intracellular distribution of dopamine melanin granules was similar to that found in neuromelanin-containing neurons. Dopamine melanin, up to 0.5 mg/ml, had negligible effects on ultrastructure, induction of the endoplasmic reticulum-stress protein glucose regulating protein 78, activation of caspase-3 and cell viability. The decreased cell viability in response to the cytotoxic peptide amyloid- ,25,35 was similar in melanin-loaded cells and in control cells without melanin. The results of the studies suggest that melanin-loaded PC12 cells can serve as an in vitro model for studies on the role of neuromelanin for the toxicity of chemicals, in particular neurotoxicants with melanin affinity, in pigmented neurons. [source] Down-Regulated PAR-2 is Associated in Part with Interrupted Melanosome Transfer in Pigmented Basal Cell EpitheliomaPIGMENT CELL & MELANOMA RESEARCH, Issue 4 2004Kazuko Sakuraba In pigmented basal cell epithelioma (BCE), there seems to be an abnormal transfer of melanized melanosomes from proliferating melanocytes to basaloid tumor cells. In this study, the interruption of that melanosome transfer was studied with special respect to the altered function of a phagocytic receptor, protease-activated receptor (PAR)-2 in the basaloid tumor cells. We used electron microscopy to clarify the disrupted transfer at the ultrastructural level and then performed immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR) to examine the regulation of a phagocytic receptor, PAR-2, expressed on basaloid tumor cells. Electron microscopic analysis revealed that basaloid tumor cells of pigmented BCE have a significantly lower population of melanosomes (,16.4%) than do normal keratinocytes located in the perilesional normal epidermis (,91.0%). In contrast, in pigmented seborrheic keratosis (SK), a similarly pigmented epidermal tumor, the distribution of melanin granules does not differ between the lesional (,93.9%) and the perilesional normal epidermis (,92.2 %), indicating that interrupted melanosome transfer occurs in BCE but not in all pigmented epithelial tumors. RT-PCR analysis demonstrated that the expression of PAR-2 mRNA transcripts in basaloid cells is significantly decreased in pigmented BCE compared with the perilesional normal epidermis. In contrast, in pigmented SK, where melanosome transfer to basaloid tumor cells is not interrupted, the expression of PAR-2 mRNA transcripts is comparable between the basaloid tumor cells and the perilesional normal epidermis. Immunohistochemistry demonstrated that basaloid cells in pigmented BCE have less immunostaining for PAR-2 than do keratinocytes in the perilesional normal epidermis whereas in pigmented SK, there is no difference in immunostaining for PAR-2 between the basaloid tumor and the perilesional normal epidermis. These findings suggest that the decreased expression of PAR-2 in the basaloid cells is associated in part with the observed interruption of melanosome transfer in pigmented BCE. [source] | |||||||||||||