marjan gharegozloo

Silymarin is a complex flavonolignan from milk thistle (Silybum marianum) plant. It exhibits cytoprotective, anticarcinogenic, and anti-inflammatory effects. Although its hepatoprotective effect has been well documented, its effects on T cells have not been thoroughly investigated. In this study, the effects of silymarin on phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT) signaling pathway of human activated T lymphocytes were investigated in vitro. Peripheral blood mononuclear cells (PBMCs) from healthy volunteers were isolated and activated with phytohaemagglutinin (PHA) and 2 µg/ml of monoclonal antibody [anti-cluster of differentiation 28 (CD28)]. Cells were incubated for 72 hours in a Roswell Park Memorial Institute (RPMI-1640) complete medium with 100 mM silymarin and dimethyl sulfoxide (DMSO) as control. Then, cell lysate was prepared with lysis buffer and cell signaling was assessed using enzyme-linked immunosorbent assay (PathScan® Cell Growth Multi-Target Sandwich ELISA Kit, Cell Signaling Technology, USA). Treatment with 100 μM silymarin for 72 hours could partially decrease the cellular levels of phosphorylated-AKT (Ser473/Thr308) and AKT. In addition, silymarin significantly decreased the cellular expression of phosphorylated-S6 (Ser235/236). Silymarin significantly decreased the cellular level of Ser235/236 but had no significant effects on cellular levels of other molecules such as AKT and Ser473/Thr308. Therefore, the inhibitory effects of silymarin on T lymphocytes proliferation, that have been observed in previous studies, might have been the result of inhibition of some molecules in the PI3K/AKT pathway which are necessary for cell cycle entrance.

Over recent decades, daily sleep duration even in children has decreased. However, sleep duration in children as an important factor in their lifestyle is usually ignored. Most of the previous studies have used subjective methods for measuring sleep pattern, which do not provide accurate estimates of the sleep quality and quantity.

Using objective method in 2009, we conducted a cross- sectional study to assess the sleep pattern of 270 (151 girls, 119 boys) primary school children aged 6-9 years living in 12 districts of Tehran, Iran. The ActiGraph GT3X (Pensacola, Florida, USA) activity monitor and a self-reported questionnaire filled out by the children’ parents were used to provide information regarding sleep pattern.

The average sleep duration of children was 524 minutes. The onset of their sleep was around 11.23 pm and morning rising time was 08.02 am. The mean sleep quality of children was 83.2% and girls had better sleep quality during week (P = 0.003) and weekday (P = 0.001) compared to boys. There was a significantly negative relationships between age and sleep duration (P = 0.003), while the association between age and the onset of sleep was positive (P = 0.001).

Our findings indicate that sleep duration and quality of the children who took part in this study were less than the normal standard recommended. In addition, the average of sleep onset in the children was too late. The pattern of older children need more consideration as the results of our study show that the older children had less sleep duration and earlier wake up time compared to the younger ones. Further studies using objective methods are required to explore the association between duration, quality, onset and wake up time of sleep and the development of mental health, physical health, and cognitive outcomes in children.