Effects of motor cortical stimulation on the excitability of contralateral motor and sensory cortices

Single pulses of transcranial magnetic stimulation (TMS) were applied to the right hemisphere over either the hand sensory area, the hand motor area (M1), ventral premotor area (vPM), dorsolateral prefrontal cortex, or 10 cm away from head (sham stimulation) in order to test the effect on motor evoked potentials (MEPs) elicited by single pulse TMS or transcranial electrical stimulus (TES) over the left M1 or the somatosensory evoked potential (SEP) elicited by an electrical stimulus to the right median nerve. The interstimulus intervals (ISIs) for MEP experiments were 50, 100, 150, 200, 300 and 400 ms, with those for SEP experiments being adjusted for the impulse conduction time from the wrist to the cortex. TMS over the right M1 reduced MEPs elicited by TMS of the left motor cortex at ISIs of 50–150 ms, whereas MEPs produced by TES were unaffected. TMS over M1 and vPM facilitated the contralateral cortical median nerve SEPs at an ISI of 100–200 ms, whereas it had no effect on tibial nerve SEPs or paired median nerve stimulation SEP. Based on these results, we conclude that at around 150-ms intervals, TMS over the motor areas (M1 and vPM) reduces the excitability of the contralateral motor area. This has a secondary effect of enhancing the responsiveness of the sensory cortex through cortico-cortical connections.     

Improvement of apical papilla cell attachment after erbium,chromium-doped yttrium,scandium, gallium,and garnet laser application: a study in an ex vivo immature tooth model

Lasers in Medical Science - The purposes of this study were (1) to investigate the direct effect of an Er,Cr:YSGG laser on human apical papilla cell (APC) proliferation and mineralization and (2)...     

Percutaneous stone removal using cobra-shaped sheath and cholangioscopy for multiple hepatolithiasis with choledochoduodenal anastomotic stenosis

Management of multiple hepatolithiasis with choledochoenteral anastomotic stenosis remains difficult and time-consuming. We report a case of a 77-year-old man with severe right hypochondoralgia, treated with percutaneous transhepatic balloon dilatation of choledocoduodenal anastomotic stenosis and percutaneous stone removal using 8Fr. cobra-shaped sheath and cholangioscopy. Hilar hepatic stones were pushed out into the duodenum through the dilated anastomosis using 5Fr. balloon catheter covered with the sheath and cholangioscopy. For stones located in the left, right anterior and aberrant right posterior hepatic ducts, a guidewire and a removal balloon catheter were inserted by using the cobra-shaped sheath. Stones pulled from the intrahepatic bile ducts to the common hepatic duct were pushed out into the duodenum. Clearance of intrahepatic bile duct stones was confirmed by balloon-occluded cholangiography using the cobra-shaped sheath and 6Fr. balloon catheter. The use of cobra-shaped sheath improved percutaneous stone removal, but the procedure needs further improvement.