Transient receptor potential canonical (TRPC) channels are non-selective calcium-permeable cation channels. It is suggested that TRPC4β is regulated by phospholipase C (PLC) signaling and is especially maintained by phosphatidylinositol 4,5-bisphosphate (PIP2 ). In this study, we present the regulation mechanism of the TRPC4 channel with PIP2 hydrolysis which is mediated by a channel-bound PLCδ1 but not by the GqPCR signaling pathway. Our electrophysiological recordings demonstrate that the Ca2+ via an open TRPC4 channel activates PLCδ1 in the physiological range, and it causes the decrease of current amplitude. The existence of PLCδ1 accelerated PIP2 depletion when the channel was activated by an agonist. Interestingly, PLCδ1 mutants which have lost the ability to regulate PIP2 level failed to reduce the TRPC4 current amplitude. Our results demonstrate that TRPC4 self-regulates its activity by allowing Ca2+ ions into the cell and promoting the PIP2 hydrolyzing activity of PLCδ1.

Owing to the rapid development of intervention techniques and devices, endovascular coil embolization of cerebral arteries has become standardized. It is particularly preferred when a patient presents with an unruptured intracranial aneurysm of the posterior communicating artery (PcomA). However, the risk of thrombogenic complications of the coil migration may also result in a large cerebral infarction. When coil migration occurs during embolization, a procedure for removal of the embolic coil should be performed immediately. We experienced a clinically rare case of migration of a framing coil to the distal middle cerebral artery aneurysm during endovascular embolization of an unruptured PcomA aneurysm. The migrated coil was barely retrieved using snare techniques.
Aneurysm ; Arteries ; Cerebral Arteries ; Cerebral Infarction ; Embolization, Therapeutic ; Humans ; Intracranial Aneurysm ; SNARE Proteins

OBJECTIVES: Despite increasing availability of global positioning system (GPS), no research has been conducted to analyze GPS data for exposure opportunities associated with time at indoor and outdoor microenvironments. We developed location-based and time-weighted spatial measures that incorporate indoor and outdoor time-location data collected by GPS. METHODS: Time-location data were drawn from 38 female subjects in California who wore a GPS device for seven days. Ambient standard deviational ellipse was determined based on outdoor locations and time duration, while indoor time weighted standard deviational ellipse (SDE) was developed to incorporate indoor and outdoor times and locations data into the ellipse measure. RESULTS: Our findings indicated that there was considerable difference in the sizes of exposure potential measures when indoor time was taken into consideration, and that they were associated with day type (weekday/weekend) and employment status. CONCLUSIONS: This study provides evidence that time-location weighted measure may provide better accuracy in assessing exposure opportunities at different microenvironments. The use of GPS likely improves the geographical details and accuracy of time-location data, and further development of such location-time weighted spatial measure is encouraged.
California ; Employment ; Female ; Geographic Information Systems* ; Humans