ABSTRACT
BACKGROUND: Hyperpigmentation disorders such as post-inflammatory hyperpigmentation are major concerns not only in light-skinned people but also in Asian populations with darker skin. The anti-tyrosinase and immunomodulatory effects of sericin have been known for decades. However, the therapeutic effects of sericin on hyperpigmentation disorders have not been well documented. METHODS: In this study, we used an in vitro model to study the anti-tyrosinase, tolerogenic, and anti-melanogenic effects of sericin on Staphylococcus aureus peptidoglycan (PEG)-stimulated melanocytes, dendritic cells (DCs), and artificial skin (MelanoDerm™). Enzyme-linked immunosorbent assay, conventional and immunolabeled electron microscopy, and histopathological studies were performed. RESULTS: The results revealed that urea-extracted sericin has strong anti-tyrosinase properties as shown by a reduction of tyrosinase activity in melanin pigments both 48 h and 10 days after allergic induction with PEG. Anti-inflammatory cytokines including interleukin (IL)-4, IL-10, and transforming growth factor-p were upregulated upon sericin treatment (10, 20, and 50 µg/mL), whereas production of allergic chemokines, CCL8 and CCL18, by DCs was diminished 48 h after allergic induction with PEG. Moreover, sericin lowered the expression of micropthalmia-associated transcription factor (MITF), a marker of melanogenesis regulation, in melanocytes and keratinocytes, which contributed to the reduction of melanin size and the magnitude of melanin deposition. However, sericin had no effect on melanin transport between melanocytes and keratinocytes, as demonstrated by a high retention of cytoskeletal components. CONCLUSION: In summary, sericin suppresses melanogenesis by inhibition of tyrosinase activity, reduction of inflammation and allergy, and modulation of MITF function.
Subject(s)
Humans , Keratinocytes/drug effects , Monophenol Monooxygenase/antagonists & inhibitors , Hyperpigmentation/drug therapy , Sericins/pharmacology , Melanocytes/drug effects , Transcription Factors/drug effects , Microscopy, Electron , Signal Transduction/drug effects , Keratinocytes/ultrastructure , Cells, Cultured , Microphthalmia-Associated Transcription Factor , Hypersensitivity , Inflammation , Melanocytes/ultrastructureABSTRACT
Melanoma es un cáncer de piel originado por los melanocitos, altamente agresivo y letal, con características macroscópica característica; se presenta caso de paciente masculino de 65 años que acude a consulta presentando masa inguinal izquierda de 3 meses de evolución, de crecimietno rápido, 10cm de diámetro, discretamente dolorosa al tacto, con antecedente de amputación supracondilia del miembro inferior ipsilateral hace 6 meses por ulcera varicosa e insuficiencia venosa crónica. Se practica biopsia incisional que reporta melanoma amelanótico una variante atípica de dificil diagnóstico. Actualmente recibiendo quimio y radioterapia.
Subject(s)
Humans , Male , Aged , Melanocytes/ultrastructure , Skin Neoplasms/pathology , Skin Neoplasms/drug therapy , Skin Neoplasms/radiotherapy , Biopsy/methods , Melanoma, Amelanotic/epidemiology , Varicose Ulcer/etiologyABSTRACT
Os autores apresentam três casos de pacientes com faixas longitudinais acastanhadas acometendo as lâminas ungueais, caracterizadas como melanoníquia estriada. A investigaçäo etiológica identificou um caso de onicomicose, um nevo da matriz ungueal e uma hiperplasia melanocítica benigna. Esses achados säo comparados com os da literatura, e säo discutidos aspectos relativos à freqüência de lesöes pigmentares ungueais de comportamento benigno
Subject(s)
Humans , Female , Male , Middle Aged , Hyperplasia/diagnosis , Melanosis/diagnosis , Nails/physiopathology , Onychomycosis/etiology , Pigmentation/physiology , Melanocytes/ultrastructureABSTRACT
The use of electron microscopy to define the cellular changes in vitiligo might prove to be a useful investigative procedure to clarify the pathogenic mechanism of this disease. Examination of vitiligenous skin taken from the margin and center of the depigmented lesions revealed ultrastructural changes in the form of cytoplasmic vacuoles in basal and suprabasal keratinocytes and deposits of extra-cellular granular material in between the keratinocytes in lower epidermis. Melanocytes and melanosomes were completely absent, while Langerhans' cells showed highly vacuolated cytoplasm. There was marked increased in degenerated Langerhans' cells in the center of the vitiligenous lesions. It seems logical to propose that degenerative changes in vitiligo do not only involve the melanocytes, but also keratinocytes and Langerhans' cells i.e. the whole epidermal- melanin unit
Subject(s)
Humans , Male , Female , Epidermis/ultrastructure , Melanins , Melanocytes/ultrastructure , Microscopy, Electron/instrumentation , Keratinocytes/ultrastructure , Immunity, Cellular , Langerhans Cells/ultrastructureABSTRACT
The mechanism of association of hypopigmentation and sensorial loss in a leprosy macular lesions has not been clarified yet. The biopsy of a macular lesion on the medial face of the right forearm of a fourteen-year old male leprosy patient was submitted to DOPA-staining for melanocytes, which is specific for the melanocytic tyrosinase enzyme and it is a proper method for identifying and couting these cells in the skin. A contralateral specimen of the same patient went through the same procedure as a control experiment. The specimen from the macular lesion showed a higher number of DOPA-stained melanocytes than the control fragment. Dermal melanocytes were present in high amounts in the abnormal specimen. Increased expression of tyrosinase by melanocytes in the macular lesions may reflect a positive feed-back stimulus represented by the lack of substance tyrosine, which may in turn be utilized by the myocobacterial agent. Ultrastructural study of the normal and pathological specimens showed no significant differences in the morphological appearance of melanocytes and their melanosomes. These results suggests that the utilization of phenolic compound by the Mycobacterium leprae may be involved in the mechanism of hypopigmentation. A higher number of cases will be necessary to confirm this hypothesis.
Subject(s)
Humans , Adolescent , Dihydroxyphenylalanine , Leprosy, Tuberculoid/physiopathology , Hypopigmentation/physiopathology , Melanocytes , Melanocytes/chemistry , Melanocytes/ultrastructureABSTRACT
Se estudia un paciente de sexo femenino, de 29 años de edad, con nevo de Ota bilateral, sin complicaciones al examen oftalmológico y leve hipoacusia de conducción derecha. Radiografía, tomografía y electroencefalograma normal. Se pasa revista a la clasificación y se lo considera de tipo difuso con pigmento en dermis papilar y reticular. En el cuadro N§1 se puntualizan las diferencias clínicas con el melasma, nevo zigomático y el nevo de Ota-"like". Se enfatiza en la necesidad de educar al paciente para su examen periódico y controlar la aparición de complicaciones, recordando que puede sufrir una transformación maligna, principalmente en piel, coroides, iris, órbita y cerebro
Subject(s)
Humans , Female , Adult , Melanocytes/pathology , Nevus of Ota/diagnosis , Diagnosis, Differential , Melanocytes/ultrastructure , Melanoma/complications , Melanosis/diagnosis , Nevus of Ota/classification , Nevus of Ota/complications , Nevus, Blue/diagnosisSubject(s)
Humans , Male , Female , Pregnancy , Adolescent , Adult , Middle Aged , Melanoma/epidemiology , Basal Cell Nevus Syndrome/epidemiology , Skin Neoplasms/diagnosis , Uveal Neoplasms/diagnosis , Melanocytes/pathology , Melanocytes/physiology , Melanocytes/ultrastructure , Melanoma/classification , Melanoma/pathology , Neoplasms, Multiple Primary/epidemiology , Neoplasms, Multiple Primary/genetics , Nevus, Pigmented/complications , Basal Cell Nevus Syndrome/physiopathology , Basal Cell Nevus Syndrome/pathology , Uveal Neoplasms/etiology , Uveal Neoplasms/geneticsABSTRACT
La mayor parte de los organismos multicelulares se caracterizan por un patrón de color distintivo y, a menudo, particular. Uno de los efectores relacionados con el proceso corresponde a células especiales, los cromatóforos. En este trabajo se demuestra mediante técnicas de microscopía electrónica, que en el dermis de reptiles sometidos a 35§C por 12 min, se produce una fuerte concentración de melanosomas en torno al núcleo de los melanóforos. Por el contrario, a 0§ los melanóforos presentan expansiones citoplasmáticas que contienen numerosos melanosomas. Asociados a los melanosomas en dispersión, se observan microtúbulos. Esta característica permite plantear la posible existencia de algún tipo de relación entre microtúbulos y movimiento de melanosomas en este reptil, cuando es sometido a bajas temperaturas, momento en que se oscurecen. Se destacan también, gruesos manojos tridimensionales de fibras colágenas asociadas a fibroblastos, estructuras, que para algunos autores, representarían un primordio de esclerificación dérmica, fenómeno que predecería a la fase fibrilar de la osificación dérmica o directa. Otro tipo de célula, los iridóforos, contienen placas reflectantes que reflejan la luz en direcciones determinadas
Subject(s)
Animals , Chromatophores/ultrastructure , Melanocytes/ultrastructure , Reptiles/anatomy & histology , Hyperthermia, Induced , Hypothermia, Induced , MicrotubulesABSTRACT
Se presenta un niño de 10 años de edad con lesiones musculosas dispuestas en arabescos y arremolinadas en tórax; lineales en miembros superiores e inferiores. Esta coexisten con afectación de SNC y compromiso óseo, dentario y ocular, constituyendo el cuadro de Hipomelanosis de Ito. Se efectúa microscopía electrónica para confirmar el diagnóstico. Se hace referencia a características clínicas y evolutivas, puntualizando las diferencias con otros síntomas neurocutáneos
Subject(s)
Humans , Child , Male , Skin Diseases, Genetic/diagnosis , Incontinentia Pigmenti/pathology , Keratinocytes/pathology , Melanocytes/ultrastructure , Nerve Endings/pathology , Pigmentation Disorders/ultrastructure , Abnormalities, Multiple , Diagnosis, Differential , Epilepsy , Incontinentia Pigmenti/diagnosis , Keratinocytes/ultrastructure , Melanocytes/pathology , Nerve Endings/ultrastructure , Neural Crest/pathology , Nevus/diagnosis , Pigmentation Disorders/diagnosis , Pigmentation Disorders/pathologyABSTRACT
Patients with vitiligo seem be less prone to the development of lentigines as a side effect of long-term photochemotherapy than do psoriatics. An 8-year-old boy who had a vitiliginous patch on his left thigh, had been receiving photochemotherapy since he was 2 years old. At the age of 3, multiple star-shaped brownish macules developed at the site of treatment. Photochemotherapy was continued until the patient was 6 year old, at which time no improvement in the vitiligo was seen, so photochemotherapy was discontinued. Now 2 years after treatment the lentigines still persist. On electron microscopic examination, the melanocytes showed two patterns of cell death: coagulative necrosis and apotosis together with atypical cytoplasmic and melanosomal alterations.
Subject(s)
Child , Humans , Male , Lentigo/etiology , Melanocytes/ultrastructure , Microscopy, Electron , PUVA Therapy/adverse effects , Vitiligo/drug therapyABSTRACT
El estudio histopatológico y ultraestructural de los nevus conjuntivales nos permitió analizar una serie de características de este tumor melánico, haciendo énfasis en la célula particular que lo forma, la célula névica, y puntualizamos similitudes y diferencias con la célula pigmentada normal conjuntival, el melanocito, permitiéndonos decir que la célula névica puede ser considerada como un melanocito atípico o modificado