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At least 235 records · Page 13Linked to original sources
PubMed1998

Skin manifestations of mitochondrial DNA syndromes: case report and review.

Mitochondrial DNA syndromes are an emerging class of diseases that can present at any age. Clinical findings are legion and may include renal tubulopathy, growth retardation, myopathy, seizures, and ophthalmoplegia. Mitochondrial DNA syndromes have presented with symmetric cervical lipomas, poikiloderma, and anhidrosis. We describe a child with a novel mitochondrial DNA syndrome who had poikiloderma on sun-exposed areas. We also reviewed 274 patients with mitochondrial DNA disorders for skin findings. Symmetric cervical lipomas were consistently associated with myoclonic epilepsy as part of 1 syndrome. With the exception of lipomas, skin findings were reported in 16 patients.

Acidosis, Lactic↗
PubMed1999

The clinical spectrum of anti-Ro-positive cutaneous neonatal lupus erythematosus.

BACKGROUND: Cutaneous neonatal lupus erythematosus (NLE) is an uncommon disease described mainly through isolated case reports. OBJECTIVE: Our purpose was to examine the cutaneous spectrum, clinical associations, and course of disease in babies with anti-Ro-positive NLE. METHODS: This is a retrospective case series evaluation of newborns with anti-Ro-positive NLE seen at a single ambulatory care university center over a 20-year period. Cases were drawn from a population of 3.2 million. Follow-up was at least 3 years. RESULTS: Four boys and 14 girls were included in our evaluation. Distribution of skin lesions in 18 babies was as follows: face, 17; periorbital "owl-eye" or "eye mask" facial rash, 14; scalp, 15; arms and legs, 13; trunk and groin, 6. Crusted lesions were predominant in 3. Photosensitivity was seen in 12, and features of cutis marmorata telangiectasia congenita were observed in 4. In 17 neonatal lupus was not suspected until the dermatology consultation. Noncutaneous manifestations included thrombocytopenia in 4, cholestatic hepatitis in 3, and congenital heart block in 3. Four patients had residual telangiectasia that persisted for 3 or more years but eventually cleared in 2 patients. Three babies had dyspigmentation that spontaneously cleared within 22 months. None had atrophy or scarring. CONCLUSION: Periorbital, scalp, and extremity lesions are common in cutaneous NLE. Crusted lesions predominated in male infants. In children selected by cutaneous involvement, thrombocytopenia and hepatic disease were present as frequently as cardiac disease and occurred more frequently in male babies with crusted skin lesions. Children with cutaneous NLE should be evaluated for hematologic and hepatic as well as cardiac involvement.

Antibodies, Antinuclear↗
PubMed1988

Chromatography of urinary indole derivatives.

Latest strategies are discussed for the routine chromatographic analysis of clinically important indole derivatives in urine. Analysis of 5-hydroxyindoleacetic acid and, perhaps more importantly, serotonin and 5-hydroxytryptophan remains attractive in the screening for carcinoid tumours and their differentiation. Analyses of two precursors of the skin pigment eumelanin seem to be promising in the monitoring of treatment of malignant melanoma and screening for pigmentation disorders and gallstone formation. Studies on the clinical relevance of the determination of tetrahydro-beta-carbolines and melatonin-related indoles await routine application of chromatographic methods designed to take into consideration the relative instability of these compounds. Application of GC-MS, although confined to larger and/or governmental laboratories remains attractive as a way of improving the specificity of analyses and in establishing reference methods. As for HPLC, the recent development of chromatographic and detection methods for the concurrent determination of different clinically important and metabolically related compounds from the same sample, preferably by direct injection techniques, seems to be fruitful and should be continued.

Animals↗
PubMed2003

[Hemophagocytic syndromes and primary immunodeficiencies].

Lymphohistiocytic activation syndromes are characterized by activation and proliferation of T cells and macrophages usually reflecting an inappropriate response of the host to an infection. The clinical manifestations are often alarming symptoms suggestive of severe sepsis. Most patients have a known underlying disease (hemopathy, lupus, Still's disease, HIV infection, bone marrow or organ transplantation). In the few cases that occur apparently without any risk factors, investigations should be done to look for a predisposing inherited disease such as familial lymphohistiocytosis or Purtilo syndrome in boys. The treatment relies on immunosuppressive agents followed by bone marrow transplantation, which can provide a definitive cure in genetics forms.

Child↗
PubMed2003

Common pediatric and adolescent skin conditions.

Skin lesions are encountered in all areas of medicine, and it is therefore important for physicians to understand the fundamentals of explaining and diagnosing common skin conditions. This article begins with a discussion of description and documentation of skin lesions based on color, size, morphology, and distribution. Pigmentation disorders such as vitiligo are depicted. Cutaneous growths that are found in the pediatric and adolescent population include acrochordons, dermatofibromas, keloids, milia, neurofibromas, and pyogenic granulomas. Treatment of these growths usually involves observation or curettage with electrodessication.Psoriasis, atopic dermatitis, poison ivy, and eczema are comprised of scaling patches and plaques; poison ivy and atopic dermatitis may also present with bullous and vesicular changes. Therapy typically consists of topical emollients and corticosteroids; phototherapy is reserved for refractory cases. Acne vulgaris is the most common skin disease of the pediatric and adolescent population. This condition can be psychologically debilitating and, therefore, proper treatment is of paramount importance. Therapeutic options include topical as well as oral antibiotics and retinoids. Extreme caution must be used when prescribing retinoids to post-pubescent females, as these agents are teratogenic. Vascular anomalies are most commonly exemplified as port wine stains and hemangiomas. Port wine stains may be treated with pulsed dye laser or may be observed if they are not of concern to the patient or physician. Hemangiomas typically spontaneously regress by age ten; however, there has been recent concern that certain cases may need to be treated. Dermal rashes may be localized or generalized. Treatment of generalized drug eruptions involves elimination of the inciting agent, topical antipruritics, and systemic corticosteroids for severe reactions. Infectious etiologic agents of skin disease include bacteria, fungi, and viruses. Many sexually transmitted diseases are bacterial or viral in origin and present as a rash or ulcer. Impetigo is a bacterial infection which may present as a bullous eruption or as an erosion with a honey colored crust. Other bacterial infections include erythema chronicum migrans, folliculitis, and cellulitis. Fungal infections include the various forms of tinea and are usually treated with topical antifungals; if the infection is located in a hair-bearing area, systemic antifungals are necessary. Viral infections include warts, varicella, molluscum contagiosum, and herpes. Treatment varies from observation or antivirals for varicella to cryosurgery and topical imiquimod for warts. Finally, scabies and lice are infectious agents that can be treated with permethrin and pyrethrin solutions.

Adolescent↗
PubMed2002

Identification of active site residues involved in metal cofactor binding and stereospecific substrate recognition in Mammalian tyrosinase. Implications to the catalytic cycle.

Tyrosinase (Tyr) and tyrosinase-related proteins (Tyrps) 1 and 2 are the enzymes responsible for mammalian melanogenesis. They display high similarity but different substrate and reaction specificities. Loss-of-function mutations lead to several forms of albinism or other pigmentation disorders. They share two conserved metal binding sites (CuA and CuB) which, in Tyr, bind copper. To define some structural determinants for these differences, we mutated Tyr at selected residues on the basis of (i) conservation of the original residues in most tyrosinases, (ii) their nonconservative substitution in the Tyrps, and (iii) their possible involvement as an endogenous bridge between the copper pair. Two mutations at the CuA site, S192A and E193Q, did not affect Tyr activities, thus excluding S192 and E193 as endogenous ligands of the copper pair. Concerning CuB, the H390Q mutation completely abolished Tyr activity, whereas Q378H and H389L mutants showed 10-20% residual specific activities. Their kinetic behavior suggests that (i) H390 is the actual third ligand for CuB, (ii) H389 is critical for stereospecific recognition of o-diphenols but not monophenols, and (iii) the involvement in metal binding of the central extra H residue at the Tyrps CuB site is unlikely. However, replacement of Q (in Tyr) by H (in Tyrps) greatly diminished the affinity for L-dopa, consistent with the low/null tyrosinase activity of the Tyrps. These are the first data showing a physical difference in docking of mono- and o-diphenols to the Tyr active site, and they are used to propose a revised scheme of the catalytic cycle.

Amino Acid Sequence↗
PubMedDate not supplied

Calcipotriol in vitiligo: a preliminary study.

A large variety of therapeutic agents have been tried for the treatment of vitiligo, but psoralens continue to be the main treatment. Twenty-one patients age 5 to 17 years with vitiligo were enrolled in this study. The children were advised to apply calcipotriol 50 microg/g in the evening and expose themselves to sunlight the next day for 10 to 15 minutes. The patients were followed at 3-week intervals. Initial repigmentation occurred in the majority of children after 6 to 12 weeks of treatment. Marked to complete repigmentation was seen in 10 of 18 patients. Four patients showed moderate improvement while the remaining four patients showed minimal or no improvement. No patient developed new lesions. The repigmentation was cosmetically excellent in the majority of children. All patients tolerated the calcipotriol well except for three patients who complained of mild irritation on application. All of the laboratory investigations, including serum calcium levels remained normal. The rationale for this study originated from recent advances in the understanding of vitiligo at the molecular level. Furthermore, development of hyperpigmentation in patients with psoriasis receiving treatment with PUVA and calcipotriol has been observed. Our results are encouraging and offer a new and potentially efficacious treatment for this pigmentation disorder in children.

Administration, Cutaneous↗
PubMedDate not supplied

Erythema dyschromicum perstans in prepubertal children.

Erythema dyschromicum perstans (EDP) is a rare disorder of pigmentation that is most common in Hispanic patients. In adults, EDP has a slow onset and is unlikely to resolve spontaneously. The etiology and clinical course in children is poorly defined. Physical examinations, chart reviews, and telephone interviews were performed for eight pediatric patients with EDP who were followed at Children's Memorial Hospital in Chicago between 1990 and 1998. All the patients available for long-term follow-up (five of the eight) experienced complete clearance without recurrence in an average of 2.5 years. In all of our patients, the onset was noted from July to December. The administration of aminopenicillins was coincident with the development of EDP in two of the patients. Review of the English-language literature reveals that 25 prepubertal children have previously been reported. Including our patients, 69% of prepubertal children with EDP experienced resolution. We concluded that the clinical course of childhood (prepubertal) EDP differs from that of adult EDP, and it is more likely to resolve within 2-3 years.

Age of Onset↗
PubMed2000

Mutations at critical N-glycosylation sites reduce tyrosinase activity by altering folding and quality control.

Tyrosinase is a copper-containing enzyme that regulates melanin biosynthesis in mammals. Mutations at a single N-glycosylation sequon of tyrosinase have been reported to be responsible for oculocutaneous albinism type IA in humans, characterized by inactive tyrosinase and the total absence of pigmentation. To probe the role that each N-glycosylation site plays in the synthesis of biologically active tyrosinase, we analyzed the calnexin mediated folding of tyrosinase N-glycosylation mutants. We have determined that four of the six potential N-glycosylation sites, including that associated with albinism, are occupied. Analysis of the folding pathway and activity of 15 tyrosinase mutants lacking one or more of the occupied N-glycosylation sites shows that glycans at any two N-glycosylation sites are sufficient to interact with calnexin and give partial activity, but a specific pair of sites (Asn(86) and Asn(371)) is required for full activity. The mutants with less than two N-glycosylation sites do not interact with calnexin and show a complete absence of enzyme activity. Copper analysis of selected mutants suggests that the observed partial activity is due to two populations with differential copper content. By correlating the degree of folding with the activity of tyrosinase, we propose a local folding mechanism for tyrosinase that can explain the mechanism of inactivation of tyrosinase N-glycosylation mutants found in certain pigmentation disorders.

Animals↗
PubMed1996

Regulation of tyrosinase gene expression by cAMP in B16 melanoma cells involves two CATGTG motifs surrounding the TATA box: implication of the microphthalmia gene product.

In melanocytes and in melanoma cells, upregulation of melanogenesis, by cAMP elevating agents, results from a stimulation of tyrosinase activity that has been ascribed to an increase in tyrosinase protein and messenger amount. However, the mechanism by which cAMP elevating agents increase tyrosinase mRNA remains to be elucidated. In this study, using a luciferase reporter plasmid containing the 2.2-kb fragment 5' of the transcriptional start site of the mouse tyrosinase gene, we showed that cAMP elevating agents lead to a strong stimulation (20-fold) of transcriptional activity of the tyrosinase promoter. Deletions and mutations in the mouse tyrosinase promoter showed that the M-box 70-bp upstream from the TATA-box and the E-box located downstream the TATA-box, near to the initiator site, are involved in the regulation of the tyrosinase promoter activity by cAMP. Additionally, we showed that microphthalmia, a b-HLH transcription factor associated with pigmentation disorders in mouse, binds to these regulatory elements and modulates the transcriptional activity of the tyrosinase promoter. Since cAMP stimulates the binding of microphthalmia to the M-box and to the E-box; it is tempting to propose that microphthalmia, through its interaction with cis-acting elements surrounding the TATA-box, plays a key role in the regulation of the mouse tyrosinase gene expression by cAMP.

3T3 Cells↗
PubMed2001

SCF/c-kit signaling is required for cyclic regeneration of the hair pigmentation unit.

Hair graying, an age-associated process of unknown etiology, is characterized by a reduced number and activity of hair follicle (HF) melanocytes. Stem cell factor (SCF) and its receptor c-kit are important for melanocyte survival during development, and mutations in these genes result in unpigmented hairs. Here we show that during cyclic HF regeneration in C57BL/6 mice, proliferating, differentiating, and melanin-producing melanocytes express c-kit, whereas presumptive melanocyte precursors do not. SCF overexpression in HF epithelium significantly increases the number and proliferative activity of melanocytes. During the induced hair cycle in C57BL/6 mice, administration of anti-c-kit antibody dose-dependently decreases hair pigmentation and leads to partially depigmented (gray) or fully depigmented (white) hairs, associated with significant decreases in melanocyte proliferation and differentiation, as determined by immunostaining and confocal microscopy. However, in the next hair cycle, the previously treated animals grow fully pigmented hairs with the normal number and distribution of melanocytes. This suggests that melanocyte stem cells are not dependent on SCF/c-kit and when appropriately stimulated can generate melanogenically active melanocytes. Therefore, the blockade of c-kit signaling offers a fully reversible model for hair depigmentation, which might be used for the studies of hair pigmentation disorders.

Animals↗
PubMed1979

Human pigment factors relative to chemical face peeling.

Two major and 18 minor complications in a series of 408 private patients undergoing partial or full-face phenol chemical peeling in a five-year period prompted a fundamental evaluation of several factors relevant to the procedure. Pigmentary change was the most common problem. Human skin pigment and factors that affect it such as hormone intake, cold exposure, ultraviolet light, medication, contact agents, and trauma are unanswered questions relative to at least pigmentary problems. Depigmentary factors were studied in an attempt to evaluate treatment of postoperative pigmentary changes.

Adult↗