We investigated the effects of change in basolateral osmolality on Na ϩ -dependent myo -inositol uptake in Madin-Darby canine kidney cells to test our hypothesis that the Na ϩ / myoinositol transporter (SMIT), an osmolyte transporter, is mainly regulated by osmolality on the basolateral surface. A significant osmotic gradient between both sides of the epithelium persisted at least 10 h after basolateral osmolality was increased. [3 H] myo -inositol uptake increased in a basolateral osmolality-dependent manner. The magnitude of the increase is comparable to that for making both sides hypertonic. Apical hypertonicity also increased the uptake on the basal side, but the magnitude of the increase was significantly smaller than the basolateral or both sides hypertonicity. Betaine-␥ -amino-n -butyric acid transporter activity, measured by [ 3 H] ␥ -amino-n -butyric uptake, showed a pattern similar to SMIT activity in response to basolateral hypertonicity. The most plausible explanation for the polarized effect of hypertonicity is that the basal membrane is much more water permeable than the apical membrane. These results seem to be consistent with the localization and regulation of the SMIT in vivo. ( J. Clin. Invest. 1996. 97: 263-267.) Key words: osmolytes • betaine • ␥ -amino-n -butyric acid • polarity • water permeability

The paper presents an embedded control software development environment that provides a tool to verify the data consistency of embedded control software designed with Simulink models and UML models. A controller model is built with MATLAB/Simulink in the control logic design phase. Then a software model that correctly executes the control logic in the actual computing environment is built in the software design phase. It must be verified during software design that the data consistency of the software is preserved in the preemptive multitask environment because the simulation of Simulink models is performed in an ideal environment in which "zero-time execution" is assumed. We present a method to verify the data consistency with SPIN model checker. We also present a tool that automatically generates Promela code for data consistency verification. We have applied the tool to a number of software models transformed from Simulink models and have confirmed its usefulness for embedded control software design.

High-throughput measurement of Ca 2+ transients in human iPSC-derived cardiomyocytes is expected to be a novel useful method to evaluate drug compound-induced cardiotoxicity in vitro. FDSS/μCELL (Hamamatsu) is an imaging microplate reader for cell-based kinetic assays that measures fluorescence/luminescence signals of all 96/384 wells in a microplate simultaneously with up to 9 ms time interval and has been widely used for measurements of intracellular Ca 2+ concentration changes in drug discovery field. Recently, we developed a 96-channel electrode array that is mounted on the FDSS/μCELL, which can add electric field stimulation (EFS) to all 96 wells of a microplate simultaneously. Using this instrumental setup, we measured Ca 2+ transients in human iPSC-cardiomyocytes with a calcium-sensitive fluorescent dye with 16 ms time interval under temperature control (37 ˚C), under spontaneous beating of cardiomyocytes or while EFS was added at various frequencies. We also examined effects of some ion channel blockers on the Ca 2+ transients in cardiomyocytes under spontaneous beating and with EFS.