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Transgenic mice expressing IFN-gamma in the epidermis have eczema, hair hypopigmentation, and hair loss.

To study the role of IFN-gamma in the pathogenesis of inflammatory skin diseases, we used the involucrin promoter to overexpress IFN-gamma in the suprabasal layers of transgenic mouse epidermis. IFN-gamma mRNA and protein were readily detectable in the skin but not in the blood. Mice exhibited striking hypopigmentation of the hair due to a reduced abundance of DOPA-positive melanocytes. Severely affected mice had reddened skin, growth retardation, hair loss, and flaky skin lesions. Keratinocyte proliferation was increased, and there was epidermal thickening with spongiosis and parakeratosis. Suprabasal beta1 integrin expression and induction of keratin 17 in interfollicular epidermis provided evidence of perturbed differentiation. IFN-gamma receptor expression was reduced, and there was induction of ICAM-1 and MHC class II molecules on the surface of transgenic keratinocytes. The skin of severely affected mice was characterized by a dermal infiltrate of T lymphocytes and macrophages/monocytes, but the epidermis was almost devoid of Langerhans cells and T lymphocytes. The number of Langerhans cells in the lymph nodes was increased in the transgenics, and autoantibodies to keratinocytes were produced. Transgenic mice showed an increased contact hypersensitivity reaction to topical application of DNFB. We conclude that constitutive IFN-gamma expression in the epidermis results in a form of eczema resembling contact dermatitis and in a profound contact hypersensitivity reaction.

Animals↗

Oculocerebral syndrome with hypopigmentation (Cross syndrome): report of a new case.

A syndrome of ocular and cutaneous hypopigmentation, severe mental retardation with spastic tetraplegia and athetosis was first observed by Cross in three siblings of an inbred Amish family. Since then, seven other patients, three sporadic and four with familial recurrence, have been reported in the literature, confirming the autosomal recessive inheritance. The clinical spectrum of the syndrome has been expanded to include true developmental defects of the CNS such as cystic malformation of the posterior fossa of the Dandy-Walker type. We report a new case of Cross syndrome.

Brain↗

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 nonresin 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.

Adult↗

Hyperpigmentation and hypopigmentation of the skin after long term PUVA therapy. Light and electron microscopic observations on three patients.

An electron microscopic study was performed to demonstrate the pathological changes induced by long term PUVA treatment in recalcitrant psoriasis. Three patients developed mottling (hyperpigmentation and hypopigmentation) during two to three years of treatment. Three different types of morphological changes were found: disarrangement of keratinocytes, clustering and stimulation of melanocytes and homogenization of papillary dermis. Furthermore, the superficial blood vessels were loaded with the same type of amorphous granular substance. These changes might be specific to PUVA treatment or they might occur only in patients with previous treatment with, e.g., arsenic, methotrexate, anthralin + UVB or a combination of these.

Adult↗

Hypopigmentation and Desquamation as Dermatologic Reactions to Aralen.

A 55-year-old white male while on Aralen(R) (chloroquine phosphate, Sanofi-Winthrop) developed desquamation and hypopigmentation of both hands. Dermatologic manifestations of chloroquine side effects are uncommon, and the appearance of desquamation has not been reported. There were no other accountable factors that appeared to contribute to this phenomenon.

Journal Article↗

Electrophysiology of retinal ganglion cells in the mouse: a study of a normally pigmented mouse and a congenic hypopigmentation mutant, pearl.

1. The organization of the receptive fields of retinal ganglion cells in te normal mouse was studied qualitatively in recordings from 43 single axons in the optic nerve and optic tract, and the light sensitivity was studied quantitatively in 26 of these cells by measuring incremental sensitivity. 2. The receptive fields of normal animals were elliptical, had concentric center and peripheral subdivisions, and had an antagonistic center/surround organization; the receptive-field centers ranged from 1.95 to 83 degrees in diameter, with a median of 7 degrees. 3. The incremental sensitivity to white light was measured using a criterion response of 10 extra spikes; the most sensitive dark-adapted cell required a stimulus luminance of 3.5 x 10(-3) cd/m2 to generate a criterion response. 4. The action spectrum measured at seven different wavelengths (433-619 nm) from ganglion cells in the normally pigmented mouse resembled the CIE (International Commission on Illumination, CIE 1957 (11)) relative scotopic luminous efficiency function (41) and is consistent with a curve having a peak around 500 nm. 5. On light adaptation with blue light (less than 460 nm), the sensitivity to longer wavelength stimuli increased by 0.2-0.5 log units relative to the sensitivity to the shorter wavelengths; these results are compatible with the presence of a photoreceptor sensitive to long wavelengths in the normally pigmented mouse (C57BL/6J+/+). 6. The organization of the receptive fields of 48 retinal ganglion cells from the hypopigmentation mutant pearl (C57BL/6J-pe) was also studied qualitatively; the receptive field organization was similar to that of the normally pigmented mouse. 7. In 25 cells from dark-adapted pearl mice, the incremental sensitivity to white light was, on the average, 1.6 log units less than that for normal mice. 8. The dark-adapted action spectrum of pearl mice was similar to that of normally pigmented mice. However, a shift in sensitivity to longer wavelengths did not occur on selective light adaptation with the most luminous blue light (less than 460 nm) background that we could produce. 9. We conclude that pearl is one of the mammalian genes that codes for functions that affect dark-adapted retinal sensitivity. The results of this study and past studies suggest that the pearl gene's action on light sensitivity is predominantly within the retina and before (distal to) the ganglion cells.

Adaptation, Physiological↗

Hypopigmentation in dogs treated with an inhibitor of platelet aggregation.

Hypopigmentation was the principal manifestation of systemic toxicity when the experimental platelet aggregation inhibitor, PD-89454, was orally administered to Beagle dogs for 28 days. Pigmentation changes were present in skin of nose, lips and eyelids and mucosa of hard palate. Fontana-Masson stain demonstrated decreased melanin within melanocytes and keratinocytes. Melanocytes were globoid with inconspicuous dendritic processes and had small, incompletely pigmented melanosomes that were quantitatively reduced relative to controls. Toxic mechanism of action of PD-89454, structurally distinct from known depigmenting compounds, was not established but ultrastructural findings suggest an interference in melanosome formation and/or melanization.

Animals↗

Oculocerebral hypopigmentation syndrome (Cross syndrome).

A typical case of Cross syndrome with hypopigmentation, mental and psychomotor retardation, spasticity, bilateral optic atrophy and dental defects in a three-year-old boy is presented. The clinical features of this rare syndrome are discussed.

Albinism, Oculocutaneous↗

Mechanisms for post-inflammatory hyperpigmentation and hypopigmentation.

Many other mediators of inflammation or biochemical pathways must be involved in producing post-inflammatory hyper and hypopigmentation. Most of these mechanisms remain to be identified. We hope the ideas presented in this report stimulate some future investigation, the results of which will improve both our own understanding of the epidermis and the role of the melanocyte as an integral part of this important issue.

Animals↗

Mechanisms of hypopigmentation in human oculocutaneous albinism.

The synthesis of melanin is ubiquitous in the animal kingdom and is under complex genetic control. Inborn errors of melanin formation, as with other inborn errors of metabolism, provide models to explore this genetic control. Human OCA is a fascinating group of disorders of melanin formation, and careful analysis of each type allows the development of hypothesis on probable mechanisms of development. The broader category of mild to moderate hypopigmentation without all of the features of albinism may ultimately prove to be as important in understanding melanin metabolism.

Albinism↗

bcl-2 deficiency in mice leads to pleiotropic abnormalities: accelerated lymphoid cell death in thymus and spleen, polycystic kidney, hair hypopigmentation, and distorted small intestine.

Transgenic mice homozygously lacking in the bcl-2 gene were generated using homologous recombination in embryonal stem cells. The complete absence of Bcl-2 alpha and -beta proteins did not interfere with normal embryonic development. Abnormalities became evident after birth, although the severity varied among homozygous null mice, bcl-2-/- mice displayed pleiotropic abnormalities similar to those in the previously described bcl-2-/- mice, including growth retardation, smaller ears, short lives, polycystic kidney, atrophic thymus and spleen with accelerated apoptotic cell death of lymphocytes, and hair hypopigmentation in the second hair follicle cycle. Our bcl-2-/- mice also revealed novel defects in the small intestine, characterized by retarded development, accelerated exfoliation of epithelial cells, and very few mitotic progenitor cells.

Abnormalities, Multiple↗

Hypopigmentation associated with an adenovirus-mediated gp100/MART-1-transduced dendritic cell vaccine for metastatic melanoma.

BACKGROUND: Reports of vitiligo associated with metastases and rare cases of spontaneous regression of disease have fueled enthusiasm for immunologic approaches to the treatment of advanced melanoma. More recent strategies have focused on using antigen-presenting dendritic cells as vaccines. OBSERVATIONS: We observed 3 cases of leukoderma associated with a novel adenovirus-mediated gp100/MART-1-transduced dendritic cell (MART indicates melanoma antigen recognized by T cells). All 3 patients had advanced metastatic melanoma. Despite the development of this leukodermic response, all patients experienced disease progression while under treatment. CONCLUSION: We provide the initial evidence for effective induction of a leukodermic response with a gp100/MART-1-transduced dendritic cell vaccine.

Adenoviridae↗

Trisomy 20 mosaicism in two unrelated girls with skin hypopigmentation and normal intellectual development.

The prenatal diagnosis of trisomy 20 mosaicism presents a challenge for practitioners and parents. The diagnosis implies an uncertain risk for an inconsistent set of physical and developmental findings, as well as a substantial chance for a child that is normal physically and developmentally. We report two girls (ages nine years one month and eight years one month) with normal intelligence and hypopigmented skin areas. Both girls were born after a prenatal diagnosis of trisomy 20 mosaicism in amniocytes. Case 1 had 83% and 57% trisomy 20 cells from two separate amniocenteses and Case 2 had 90% trisomy 20 cells from an amniocentesis. Trisomy 20 was confirmed after birth in urinary sediment (25%) and chorionic villus cells (15%) in Case 1, while cord blood lymphocytes (30 cells) and skin fibroblasts (50 cells) had only 46,XX cells. Trisomy 20 was confirmed after birth in urinary sediment (100%), placenta (100%), cord (10%), amniotic membrane (50%), and skin fibroblasts (30%) in Case 2, while cord blood lymphocytes (100 cells) had only 46,XX cells. This is the first report of a hypopigmented pigmentary dysplasia associated with isolated trisomy 20 mosaicism. Our patients are the oldest reported children with trisomy 20 mosaicism confirmed after birth.

Chromosomes, Human, Pair 20↗