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PubMed1999

Oxidative damage and age-related macular degeneration.

This article provides current information on the potential role of oxidation in relation to age-related macular degeneration (AMD). The emphasis is placed on the generation of oxidants and free radicals and the protective effects of antioxidants in the outer retina, with specific emphasis on the photoreceptor cells, the retinal pigment epithelium and the choriocapillaris. The starting points include a discussion and a definition of what radicals are, their endogenous sources, how they react, and what damage they may cause. The photoreceptor/pigment epithelium complex is exposed to sunlight, is bathed in a near-arterial level of oxygen, and membranes in this complex contain high concentrations of polyunsaturated fatty acids, all considered to be potential factors leading to oxidative damage. Actions of antioxidants such as glutathione, vitamin C, superoxide dismutase, catalase, vitamin E and the carotenoids are discussed in terms of their mechanisms of preventing oxidative damage. The phototoxicity of lipofuscin, a group of complex autofluorescent lipid/protein aggregates that accumulate in the retinal pigment epithelium, is described and evidence is presented suggesting that intracellular lipofuscin is toxic to these cells, thus supporting a role for lipofuscin in aging and AMD. The theory that AMD is primarily due to a photosensitizing injury to the choriocapillaris is evaluated. Results are presented showing that when protoporphyric mice are exposed to blue light there is an induction in the synthesis of Type IV collagen synthesis by the choriocapillary endothelium, which leads to a thickened Bruch's membrane and to the appearance of sub-retinal pigment epithelial fibrillogranular deposits, which are similar to basal laminar deposits. The hypothesis that AMD may result from oxidative injury to the retinal pigment epithelium is further evaluated in experiments designed to test the protective effects of glutathione in preventing damage to cultured human pigment epithelial cells exposed to an oxidant. Experiments designed to increase the concentration of glutathione in pigment epithelial cells using dimethylfumarate, a monofunctional inducer, are described in relation to the ability of these cells to survive an oxidative challenge. While all these models provide undisputed evidence of oxidative damage to the retinal pigment epithelium and the choriocapillaris that is both light- and oxygen-dependent, it nevertheless is still unclear at this time what the precise linkage is between oxidation-induced events and the onset and progression of AMD.

Antioxidants↗
PubMed1992

Alkaptonuria and ochronosis: case report and review.

Alkaptonuria is a rare genetic disorder in which the enzyme homogentisic acid oxidase is deficient, resulting in the accumulation of homogentisic acid in various bodily tissues. This is a multisystem disorder with a characteristic blue-black discoloration of the skin and cartilage, which is termed ochronosis. Herein we report a profound case of ochronosis secondary to alkaptonuria. Furthermore, we review the clinical manifestations of alkaptonuria and discuss the spectrum of ochronosis, both endogenous and exogenous.

Aged↗
PubMed1982

Hypopigmented mycosis fungoides: report of five cases with ultrastructural observations.

Five dark-skinned individuals presented with widespread well-demarcated hypopigmented lesions, biopsy of which revealed the histopathological features of mycosis fungoides. Ultrastructural studies showed focal invasion of the epidermis by mycosis cells with degenerative changes in adjacent melanocytes and keratinocytes. The majority of melanocytes exhibited swelling of cytoplasmic organelles and disordered melanogenesis with production of spherical incompletely melanized melanosomes. In addition disintegrating melanocytes were occasionally seen. Perifollicular repigmentation within hypopigmented areas occurred in two patients following clearing of the epidermal infiltrate with PUVA therapy. Mycosis fungoides may present with areas of cutaneous hypopigmentation.

Adolescent↗
PubMed1992

Bronchoalveolar disease in dyskeratosis congenita.

Dyskeratosis congenita (DC) is an unusual familial disorder primarily affecting the skin and its appendages. We report the case of a DC patient with chronic respiratory tract involvement, confirming the features previously reported by a small number of authors: 1) chronic bronchoalveolar involvement is not unusual in this disorder; 2) the main features are early sputum production with subsequent bronchial and alveolar destruction; 3) after onset of dyspnoea the course is rapidly fatal, with progressive respiratory failure. Immune deficiency and repeated bronchoalveolar infections may be involved in the pathogenesis of these manifestations.

Adult↗
PubMed1987

Neurofibromatosis and Albright's syndrome.

For both NF and Albright's syndrome, the pathogenetic relationships between the various elements of the respective syndromes remain a mystery, and the importance of nontumorous endocrine abnormalities in neurofibromatosis has, in my opinion, been overstated. Nonetheless, the parallel between the two disorders is striking, and the consistent occurrence of skin and skeletal dyplasias in both suggests that a search for the fundamental defect in either can be advanced by focusing on what is common to these two types of tissue. For example, how does one reconcile a disturbance of the melanosome with skeletal aberrations? An answer to that question will put us on the right track. One final question must be asked. Are neurofibromatosis and Albright's syndrome alternate manifestations of the same disorder? In a trivial sense, the answer may be yes. That is, in at least some instances, one condition may have been mistaken for the other, and thus a factitious overlap or "sameness" misconstrued. Upon closer scrutiny, however, there are two important points that would cast doubt on a positive response to this question: Neurofibromatosis, or at least neurofibromatosis I, is heritable as an autosomal dominant trait, whereas heritability has not been documented for Albright's syndrome; and I am unaware of reported cases that describe both disorders, diagnosed by criteria beyond café au lait spots and bone dysplasia, in one and the same individual, although such a case has been shared with me by S. A. Sorensen, M.D., of the Genetics Institute of Copenhagen, Denmark. The full reporting of such a case would be of great interest.

Fibrous Dysplasia of Bone↗
PubMedDate not supplied

Abnormal vessel patterns in phototoxic rat retinopathy studied by vascular replicas.

Permeability abnormalities of vessels in rat phototoxic retinopathy have been described for sodium fluorescein and the fluoresceinated dextrans. Since fenestrated vessels within the pigment epithelium (RPE-vessels) had connections to retinal capillaries but not to choroidal vessels, it was presumed that the continuous retinal vessels became fenestrated when located in the abnormal environment of the pigment epithelial cell. It was necessary to rule out a choroidal origin of these unusual RPE-vessels, since they may be a model for other vasculopathies. Vascular cast replicas of whole retinal and choroidal vessel beds from rats with advanced phototoxic retinopathy were studied by scanning electron microscopy. No connection between the retinal and choroidal vasculature was found. Retinal vessels entering the pigment epithelium formed medusa-like coils in local areas. Marked capillary dropout and vessel tortuosity were characteristic. The choroidal capillary bed was normal. This model is appropriate for study of the plasticity of retinal capillaries as seen in diabetic retinopathy and senile macular degeneration.

Animals↗
PubMed2002

Cosmetic camouflage advice improves quality of life.

BACKGROUND: The subjective benefit of attendance at cosmetic clinics has not previously been reported. OBJECTIVES: To assess the effect on perceived quality of life (QoL) of cosmetic camouflage advice. METHODS: In a three-centre study, 135 individuals were invited to complete a dermatology-specific QoL measure, the Dermatology Life Quality Index (DLQI), before and 1 month after their first visit to a cosmetic camouflage clinic. RESULTS: Eighty-two completed DLQI questionnaires were returned before the camouflage clinic appointment, and 56 corresponding questionnaires were returned 1 month after. The mean age of responders was 50 years, and the mean duration of their skin conditions was 15 years. The main conditions seen were pigmentary disorders (29%), scars (22%) and vascular disorders (13%). There was a significant difference in mean DLQI scores before and after the clinic visit (9.1 vs. 5.8, P = 0.0001). CONCLUSIONS: When assessed at 1 month, attendance at a cosmetic camouflage clinic appears to improve QoL significantly.

Activities of Daily Living↗
PubMed1994

Molecular basis of human piebaldism.

Piebaldism is an autosomal dominant genetic disorder of pigmentation characterized by congenital patches of white skin and hair that lack melanocytes. Piebaldism results from mutations of the KIT proto-oncogene, which encodes the cell-surface receptor transmembrane tyrosine kinase for an embryonic growth factor, Steel factor. Several pathologic mutations of the KIT gene have now been identified in different patients with piebaldism. Correlation of these mutations with the associated piebald phenotypes has led to the recognition of a hierarchy of three classes of mutations that result in a graded series of piebald phenotypes, and to improved understanding of the mechanisms that underlie dominant genetic disorders.

Genes↗
PubMed1982

[Acquired leukomelanoderma caused by topical depigmenting agents].

Three patients applied a cream containing monobenzyl ether (MBEH) (2 cases) or monomethyl ether of hydroquinone (1 case) on acquired hyperpigmentary disorders. We observed depigmentation locally and at a distance from the treated areas. The depigmenting ability of MBEH was founding in 1939 by Oliver, at the time of an occupational accident. This happended among black workers wearing rubber gloves containing MBEH as an anti-oxydant. The depigmenting ability has been used as a treatment for acquired hyperpigmentary disorders, but adverse effects were observed--irritation and local sensitization--depigmentation locally and at a distance from the treated areas--melanoleukodermia among asiatics--no repigmentation: therefore treatment with MBEH has been used by Mosher in extensive vitiligo on the unaffected areas. As regards to the mechanism of these pigmentary disorders, knowledge is incomplete, particulary concerning depigmentation at a distance: hypothesis was: destruction by degrees of the melanocytes, as in Lerner's theory concerning vitiligo, autoimmune mechanism? Genetic predisposition? Electron microscopy shows cellular disturbances in melanosomes and degeneration of intracytoplasmic membrane thus killing cell. The physiopathology was the work of Riley: he has shown that MBEH is selectively incorporated into cultured melanocytes. Evidence of free radical formation has been obtained in guinea-pig skin treated with this agent. Cultured melanocytes are irreversibly damaged by exposure to low concentrations. Riley postulates that these compounds diffuse into melanosomes of the pigment cell where they are oxidized by tyrosinase to produce free radicals; the latter bring about lipid peroxidation of cell membrane lipids, thus killing the cell.

Adult↗
PubMed1981

The Patterson syndrome, leprechaunism, and pseudoleprechaunism.

A bizarre syndrome has hitherto masqueraded as leprechaunism, and although it is a quite different disorder it has been used as the prototype of leprechaunism in some birth defects atlases. It is proposed that this condition is designated the Patterson syndrome and details of a second case are reported. The features of this connective tissue and neuroendocrine disorder include bronzed hyperpigmentation, cutis laxa of the hands and feet, bodily disproportion, severe mental retardation, and major bony deformities. Radiographs revealed a unique and gross generalised skeletal dysplasia, unlikely to be confused with any other disorder. This endocrine abnormality comprised hyperadrenocorticism, cushingoid features, and diabetes mellitus in the first case, and premature adrenarche in the second case. The pathogenesis and aetiology of the Patterson syndrome are unknown, although quantitative and qualitative abnormalities of mucopolysaccharide excretion were found in the second case.

Bone Diseases, Developmental↗
PubMed2004

Congenital neuropathy and dilution of feather melanin in nestlings of urban-breeding northern goshawks (Accipiter gentilis).

A pair of northern goshawks (Accipiter gentilis) breeding in a public park in the city center of Hamburg, Germany, raised 12 healthy and five aberrant offspring between 1996 and 2000. Aberrant nestlings (three males and two females) had pale silver-blue plumage and displayed severe locomotor disorders. Histopathologically, the defects were characterized by adendritic feather melanocytes and mild degeneration of the cerebellar white matter. Epidemiologic results were suggestive of a hereditary autosomal recessive defect, which may have originated from close inbreeding during the foundation of Hamburg's urban population of northern goshawks.

Animals↗
PubMed1991

Pachyonychia congenita-like disorder in cotton-top tamarins (Saguinus oedipus oedipus).

A spontaneous genodermatosis in 13 cotton-top tamarins is described as a retrospective study. The disease appeared as alopecia, pigmentary disturbances, and claw dystrophy similar but not identical to human Pachyonychia congenita. The disease in the tamarins seems to be inherited as an autosomal recessive trait, becoming clinically apparent around adolescence. In certain families the neonatal mortality rate was also above average, reaching 100%.

Alopecia↗
PubMed1988

The gene for incontinentia pigmenti: failure of linkage studies using DNA probes to confirm cytogenetic localization.

Probes for restriction fragment length polymorphisms mapping between Xp21 and Xq22.3 have been used in a linkage study of incontinentia pigmenti (IP). Six independent sporadic cases of disorders resembling IP with X-autosome translocations involving the same X chromosome breakpoint (Xp11) have been reported. These observations suggest that the IP gene may be located in the Xp11 chromosomal region. However, the linkage study with DNA probes has failed to confirm this localisation.

Chromosome Mapping↗
PubMed1999

Notalgia paresthetica: clinical, physiopathological and therapeutic aspects. A study of 12 cases.

Notalgia paresthetica (NP) is a common but often unrecognized neurocutaneous condition, with very few cases reported to date. It is characterized by pruritus localized in an area between D2 and D6 dermatomes, sometimes accompanied by sensory neuropathies and/or electrical conductivity disorders. Cutaneous pigmented patches and friction amyloidosis can arise with irritation. Some hereditary cases have been noted mainly in young patients, associated with multiple endocrine neoplasia type 2A. However, NP mainly occurs in older patients and most are sporadic pathologies linked with musculoskeletal compression of spinal nerves. Only capsaicin has shown some (but unfortunately only transient) efficacy in relieving NP symptoms. We present observations on 12 sporadic cases of NP. Spinal X-rays revealed dorsal arthrosis or spinal static disequilibrium in nine of these patients. Six patients underwent spinal and paraspinal ultrasound or radiation (better) physiotherapy, and the symptoms subsided in four of these cases. These results highlighted that spinal disorders could be a determining factor in NP, indicating that patients could benefit from physiotherapy.

Adrenal Cortex Hormones↗
PubMed1985

Hyperpigmentation, vitiligo, and Addison's disease.

Addison's disease is an uncommon disorder whose dermatologic manifestations range from vitiligo to hyperpigmentation. The association of adrenal autoantibodies and vitiligo has made the latter a possible cutaneous marker for an autoimmune cause. The other cutaneous marker, hyperpigmentation, is now more clearly understood on the basis of a prohormone common to both adrenocorticotrophic hormone (ACTH) and melanocyte-stimulating hormone (MSH).

Addison Disease↗