Melanocytes in the human epidermis actively produce and secrete various substances, thereby contributing to the maintenance of the skin homeostasis. Lipocalin-type prostaglandin D synthase (L-PGDS) that catalyzes the formation of prostaglandin D(2) (PGD(2) ) may be one of such secreted molecules. Once secreted, L-PGDS functions as a transporter for lipophilic ligands, including all-trans retinoic acid (RA). L-PGDS, therefore, may possess pleiotropic functions in the skin through PGD(2) and RA. We aimed to identify the cell types that express L-PGDS in human skin and to explore the role of L-PGDS in the growth potential of melanocyte-lineage cells. Immunohistochemical analysis for L-PGDS expression was performed with the tissue sections that were prepared from five malignant melanomas, six nevus cell nevi and one Spitz nevus. Normal skin tissues adjacent to the excised melanoma tissues were also analyzed. L-PGDS is expressed in epidermal melanocytes but its expression is undetectable in keratinocytes. Moreover, L-PGDS is undetectable in most benign nevus cells, which may reflect the marginally accelerated proliferation of nevus cells. In contrast, L-PGDS is overexpressed in malignant melanomas, although the frequency of L-PGDS-positive cells was variable (15-50%), depending on the specimens. Lastly, RNA interference analysis against human L-PGDS was performed with short interfering RNA. Knockdown of L-PGDS expression with short interfering RNA in cultured cells suggests that L-PGDS may restrict cell proliferation through RA. In conclusion, L-PGDS expression may contribute to the restricted proliferation of epidermal melanocytes, but conversely its overexpression may reflect the dysregulated proliferation of melanoma cells.
4 Bystryn JC, Orentreich N, Stengel F. Direct Immunofluorescence studies in alopecia areata and male pattern alopecia. J Invest Dermatol 1979; 73: 317-320. 5 Blenkinsopp WK, Clayton RJ, Haffenden GP. Immunoglobulin and complement in normal skin.The pathogenesis of mucinous eccrine naevus is currently unclear. Llombart et al. 2 suggested that a potential defect in embryogenesis might be involved but also recognized that cases presenting in adulthood argued against this hypothesis. Regarding the mucinous deposit, EspaNa et al. hypothesized that stimuli such as growth factors that stimulate fibroblasts might play a role in increasing mucin synthesis. 4
Tourette Syndrome [TS] is characterized by multiple, involuntary and repetitive motor and vocal tics. In addition, a number of subtle behavioral atypicalities are often mentioned in the clinical literature, but ha ve received scant empirical attention. To investigate a broad range of behavioral symptoms associated with TS, scores on the Achenbach Child Behavior Checklist [CBC] were compared for 21 TS patients, 21 childhood migraine patients, and 21 idiopathic seizure disorder patients, matched for age lx=l2.5 years) and sex (7 girls and 14 boys per group). Chi-square analysis of the CBC items revealed significantly greater frequencies of crying, of fears and phobias, of obsessive thoughts, and worrying among the TS children. Findings demonstrate a more pronounced tendency to demand attention, to feel guilty, to have strange ideas, and to engage in compulsive activities. The TS children are more likely to bite their nails, to pick at body parts, and to store things up for which they have no need. They are also more likely to be have shyly and to be teased by other children. Further analysis of the CBC factors revealed higher factor scores among the TS children on Hyperactivity, Non-communicativeness, and Social-withdrawal, with significantly more scores falling outside the range of normal (T score > 70) among the TS children than among the migraine or seizure disorder c hildren.
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