Time related Characteristics of cardiac systole, diastole, baroreeeptor activity and inactivity during vagal stimulation and mild haemorrhage in the dog

The duration of cardiac systole and diastole in each individual cardiac cycle were measured from aortic pressure curves during vagal stimulation and mild haemorrhage with simultaneous recording of aortic baroreceptor single fibre nerve activity. The duration of cardiac diastole was highly correlated with the duration of cardiac cycle in all the interventions. The correlation coefficient between the duration of cardiac systole and the duration of cardiac cycle was not as high as that between the duration of cardiac cycle and cardiac diastole. A highly linear correlation also existed between the duration of cardiac cycle and the duration of baroreceptor inactivity time. The same was true when the duration of baroreceptor inactivity time was compared with the duration of cardiac diastole. It is concluded that the duration of baroreceptor inactivity time may inform the central nervous system about heart rate

Lasten ympäristö ja terveys : Kansallinen CEHAP-selvitys

Painetun version ISBN 978-951-740-698-7Kansallinen lasten ympäristö ja terveys -toimintaohjelma, joka pohjautuu eurooppalaiseen toimintaohjelmaan (Children's Environment and Health Action Plan for Europe, CEHAPE

Group X Phospholipase A2 Stimulates the Proliferation of Colon Cancer Cells by Producing Various Lipid Mediators

Among mammalian secreted phospholipases A2 (sPLA2s), the group X enzyme has the most potent hydrolyzing capacity toward phosphatidylcholine, the major phospholipid of cell membrane and lipoproteins. This enzyme has recently been implicated in chronic inflammatory diseases such as atherosclerosis and asthma and may also play a role in colon tumorigenesis. We show here that group X sPLA2 [mouse (m)GX] is one of the most highly expressed PLA2 in the mouse colon and that recombinant mouse and human enzymes stimulate proliferation and mitogen-activated protein kinase activation of various colon cell lines, including Colon-26 cancer cells. Among various recombinant sPLA2s, mGX is the most potent enzyme to stimulate cell proliferation. Based on the use of sPLA2 inhibitors, catalytic site mutants, and small interfering RNA silencing of cytosolic PLA2α and M-type sPLA2 receptor, we demonstrate that mGX promotes cell proliferation independently of the receptor and via its intrinsic catalytic activity and production of free arachidonic acid and lysophospholipids, which are mitogenic by themselves. mGX can also elicit the production of large amounts of prostaglandin E2 and other eicosanoids from Colon-26 cells, but these lipid mediators do not play a role in mGX-induced cell proliferation because inhibitors of cyclooxygenases and lipoxygenases do not prevent sPLA2 mitogenic effects. Together, our results indicate that group X sPLA2 may play an important role in colon tumorigenesis by promoting cancer cell proliferation and releasing various lipid mediators involved in other key events in cancer progression