Women are affected by winter seasonal affective disorder (SAD) more often than men. The female/male ratio is reported to range from 2:1 to 40:1 in samples of patients with winter SAD. It is suggested that this preponderance of women is based on the action of the ovarian steroid hormones estrogen and progesterone. However, the detailed mechanisms of action are not well understood to date. A new hypothesis claims that, in women with winter SAD, decreased levels of estradiol in the ventromedial hypothalamus Cheap Hollister Clothing are associated with the occurrence of atypical symptoms of depression, including increased daytime Hollister Toronto Locations
sleepiness and hypersomnia during the winter.
Myosins constitute a large superfamily of actin-dependent molecular motors. Phylogenetic analysis currently places myosins into 15 classes. The conventional myosins which form filaments in muscle and non-muscle cells form class II. There has been extensive characterization of these myosins and much is known about their function. With the exception of class I and class V myosins, little is known about the structure, enzymatic properties, intracellular localization and physiology of most unconventional myosin classes. This review will focus on myosins from class IV, VI, VII, VIII, X, XI, XII, XIII, XIV and XV. In addition, the function of myosin II in non-muscle cells will also be discussed.