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Biomedical subjects

F Wren

Publications and source records attributed to F Wren.

4 recordsLinked to original sources
PubMed1993

Locomotor activity in depressed children and adolescents: I. Circadian dysregulation.

OBJECTIVE: To determine whether circadian activity rhythms were altered in pediatric patients with depression. Evidence was sought for a shift in the timing of the rhythm, blunting of circadian amplitude, or emergence of noncircadian periodicities. METHOD: Locomotor activity was quantified in 57 patients with major depressive mood disorders (mean age 12.4 years) and 16 normal controls (9.9 years). Activity was measured in 5-minute epochs during 72 hours using belt-worn electronic activity monitors. RESULTS: Patients with mood disorders displayed a 15% decrease in the amplitude of their circadian rhythm, and a 52% increase in the magnitude of their twice-daily (hemicircadian) rhythm. No significant difference emerged in the timing of the circadian rhythm. Depressed inpatients and outpatients displayed comparable disturbances, which were most marked in adolescents. CONCLUSIONS: Circadian activity rhythms were dysregulated in pediatric patients with major depression. These findings may have etiological and diagnostic significance.

Adolescent↗
PubMed1990

Alpha-MSH causes a small rise in cAMP but has no effect on basal or ultraviolet-stimulated melanogenesis in human melanocytes.

The effects of alpha-melanocyte stimulating hormone (alpha-MSH) were studied on levels of cyclic adenosine 3',5'-monophosphate (cAMP), melanin content and response to ultraviolet radiation (UVR) in cultured human melanocytes (HuMC). Foreskin HuMC were cultured in a hormone-supplemented system not dependent on the presence of phorbol esters. Following addition of alpha-MSH (10(-6) M) there was a rise in cAMP levels maximal between 5 and 15 min to 9.4 +/- 3.2 pM/10(5) cells, while control levels were 3.6 +/- 0.7 pM/10(5) cells. After 7 days' culture in the presence of alpha-MSH (10(-8) -10(-6) M) the melanin content increased by only 35%, whereas Forskolin (10(-5) M) induced a 9.5-fold rise in cAMP after 5 min and a 10.9-fold rise in melanin content after 7 days. When HuMC were irradiated daily for 6 days with UVR (Helarium fluorescent lamps emitting 20% UVB, 80% UVA) melanin content rose 2.7-fold (SE 0.3). This was unchanged or slightly reduced in the presence of alpha-MSH (10(-8)-10(-6) M). Parallel observations on Cloudman S91 melanoma cells showed that alpha-MSH caused only an 80% increase in melanin content after 4 days. The rise in melanin content induced by three daily UV-irradiations (2.4-fold, SE 0.5) was unchanged by alpha-MSH (10(-8)-10(-6) M). Although alpha-MSH induces a small rise in cAMP in HuMC this does not result in melanogenesis, and the response to UVR is not affected by alpha-MSH in either HuMC or S91 cells.

1-Methyl-3-isobutylxanthine↗