1 The results of prophylactic measures for femoral head AVN have considerable variation, but certain generalizations can safely be stated. 2  Namely, the clinical results of core decompression alone deteriorate with more advanced lesions.
1 Melasma is very common skin ailment. It can occur to anyone, but young women with brownish tone are more likely to contract with it.  The condition is often linked with female hormonal changes. Change in level of estrogen and progesterone may cause melasma.
The melanocortin 1 receptor controls which type of melanin is produced by melanocytes. When the receptor is activated, it triggers a series of chemical reactions inside melanocytes that stimulate these cells to make eumelanin. If the receptor is not activated or is blocked, melanocytes make pheomelanin instead of eumelanin.