Intracellular Ca Mobilization and Beta-hexosaminidase Release Are Not Influenced by 60 Hz-electromagnetic Fields (EMF) in RBL 2H3 Cells.

The effects of extremely low frequency electromagnetic fields (EMF) on intracellular Ca(2+) mobilization and cellular function in RBL 2H3 cells were investigated. Exposure to EMF (60 Hz, 0.1 or 1 mT) for 4 or 16 h did not produce any cytotoxic effects in RBL 2H3 cells. Melittin, ionomycin and thapsigargin each dose-dependently increased the intracellular Ca(2+) concentration. The increase of intracellular Ca(2+) induced by these three agents was not affected by exposure to EMF (60 Hz, 1 mT) for 4 or 16 h in RBL 2H3 cells. To investigate the effect of EMF on exocytosis, we measured beta-hexosaminidase release in RBL 2H3 cells. Basal release of beta-hexosaminidase was 12.3±2.3% in RBL 2H3 cells. Exposure to EMF (60 Hz, 0.1 or 1 mT) for 4 or 16 h did not affect the basal or 1 µM melittin-induced beta-hexosaminidase release in RBL 2H3 cells. This study suggests that exposure to EMF (60 Hz, 0.1 or 1 mT), which is the limit of occupational exposure, has no influence on intracellular Ca(2+) mobilization and cellular function in RBL 2H3 cells.

Trust on doctor, social capital and medical care use of the elderly.

Using data from a survey sample of people 65 years of age and older living in Seoul and Chuncheon, Korea, this paper assesses whether the level of social capital affects elderly individuals' use of medical care. As an econometric model, Heckman's Sample Selection model and the 2SLS method were used to control the endogeneity problem of patient's trust on doctors. The results of our estimations indicate that the level of social capital exerts a positive effect on elderly individuals' use of medical care indirectly, via its positive effect on the level of trust in doctors.

Lutein is a competitive inhibitor of cytosolic Ca²+-dependent phospholipase A2.

OBJECTIVES: We have investigated the effect of lutein on phospholipase A2 (PLA2) isozymes. METHODS: We measured arachidonic acid release in [³H]arachidonic acid-labelled Raw 264.7 cells and PLA2 activity using 1-palmitoyl-2-[¹4C]arachidonyl phosphatidylcholine ([¹4C]AA-PC) and 10-pyrene phosphatidylcholine in vitro. KEY FINDINGS: Lutein suppressed the release of arachidonic acid and inhibited Raw 264.7 cell-derived cytosolic Ca²+-dependent PLA2 (cPLA2-induced hydrolysis of [¹4C]AA-PC in a dose- and time-dependent manner. In contrast, lutein did not affect secretory Ca²+-dependent PLA2 (sPLA2)-induced hydrolysis of [¹4C]AA-PC. A Dixon plot showed that the inhibition by lutein on cPLA2 appeared to be competitive with an inhibition constant, K(i) , of 13.6 µm. CONCLUSIONS: We suggest that lutein acted as a competitive inhibitor of cPLA2 but did not affect sPLA2.

Aortic thrombosis resolved with enoxaparin in a patient treated with cisplatin-based regimen for small cell lung cancer.

We present a rare case of a thrombus at the aortic arch found 1 month after cisplatin-based chemotherapy in a 50-year-old patient with a diagnosis of small cell lung cancer; there were no symptoms related to the thrombus. This patient did not have any predisposing factors for the development of an aortic thrombus before the chemotherapy was initiated. After immediate treatment with low molecular weight heparin (enoxaparin), the thrombus improved without any additional complications. Thus, we suggest that a hypercoagulable status possibly created by both the malignancy and cisplatin-based chemotherapy may have played a significant role in the development of the aortic thrombus.

Effect of Extremely Low Frequency Electromagnetic Fields (EMF) on Phospholipase Activity in the Cultured Cells.

This study was conducted to investigate the effects of extremely low frequency electromagnetic fields (EMF) on signal pathway in plasma membrane of cultured cells (RAW 264.7 cells and RBL 2H3 cells), by measuring the activity of phospholipase A(2) (PLA(2)), phospholipase C (PLC) and phospholipase D (PLD). The cells were exposed to the EMF (60 Hz, 0.1 or 1 mT) for 4 or 16 h. The basal and 0.5 µM melittin-induced arachidonic acid release was not affected by EMF in both cells. In cell-free PLA(2) assay, we failed to observe the change of cPLA(2) and sPLA(2) activity. Also both PLC and PLD activities did not show any change in the two cell lines exposed to EMF. This study suggests that the exposure condition of EMF (60 Hz, 0.1 or 1 mT) which is 2.4 fold higher than the limit of occupational exposure does not induce phospholipases-associated signal pathway in RAW 264.7 cells and RBL 2H3 cells.