Release and uptake mechanisms of vesicular Ca stores

Cells utilize calcium ions (Ca) to signal almost all aspects of cellular life, ranging from cell proliferation to cell death, in a spatially and temporally regulated manner. A key aspect of this regulation is the compartmentalization of Ca in various cytoplasmic organelles that act as intracellular Ca stores. Whereas Ca release from the large-volume Ca stores, such as the endoplasmic reticulum (ER) and Golgi apparatus, are preferred for signal transduction, Ca release from the small-volume individual vesicular stores that are dispersed throughout the cell, such as lysosomes, may be more useful in local regulation, such as membrane fusion and individualized vesicular movements. Conceivably, these two types of Ca stores may be established, maintained or refilled via distinct mechanisms. ER stores are refilled through sustained Ca influx at ER-plasma membrane (PM) membrane contact sites (MCSs). In this review, we discuss the release and refilling mechanisms of intracellular small vesicular Ca stores, with a special focus on lysosomes. Recent imaging studies of Ca release and organelle MCSs suggest that Ca exchange may occur between two types of stores, such that the small stores acquire Ca from the large stores via ER-vesicle MCSs. Hence vesicular stores like lysosomes may be viewed as secondary Ca stores in the cell.

Present status of oxygen supply devices for high altitude parachuting at home and abroad / 医疗卫生装备

The necessity of paratroopers equipped with high altitude parachuting oxygen supply devices was elaborated firstly,the selection of oxygen source,working principle and the physiological requirements of high altitude parachuting oxygen supply device were also expounded in detail.The technical indexes of high altitude parachuting oxygen supply devices produced by COBHAM and Airborne systems were mainly introduced.The present status of high altitude parachuting oxygen supply devices in China was summarized.The advantages of high altitude parachuting oxygen supply devices at abroad were analyzed,the gaps between domestic and foreign high altitude parachuting oxygen supply devices and the future development direction of them in China were proposed.In order to provide life support for paratroopers to perform special tasks such as parachuting,the following points need to be specified:more scientific researches need to be strengthened in China and the superior performance of high altitude parachuting oxygen supply devices than foreign ones should be developed as soon as possible.