Cell shape regulates subcellular organelle location to control early Ca2+ signal dynamics in vascular smooth muscle cells.

The shape of the cell is connected to its function; however, we do not fully understand underlying mechanisms by which global shape regulates a cell's functional capabilities. Using theory, experiments and simulation, we investigated how physiologically relevant cell shape changes affect subcellular organization, and consequently intracellular signaling, to control information flow needed for phenotypic function. Vascular smooth muscle cells going from a proliferative and motile circular shape to a contractile fusiform shape show changes in the location of the sarcoplasmic reticulum, inter-organelle distances, and differential distribution of receptors in the plasma membrane. These factors together lead to the modulation of signals transduced by the M3 muscarinic receptor/Gq/PLCß pathway at the plasma membrane, amplifying Ca2+ dynamics in the cytoplasm, and the nucleus resulting in phenotypic changes, as determined by increased activity of myosin light chain kinase in the cytoplasm and enhanced nuclear localization of the transcription factor NFAT. Taken together, our observations show a systems level phenomenon whereby global cell shape affects subcellular organization to modulate signaling that enables phenotypic changes.

Application of time-delay spectrometry for calibration of ultrasonic transducers.

Time-delay spectrometry (TDS) can conveniently be used for calibration and performance evaluation of piezoelectric electroacoustic transducers. The main emphasis of the work reported here is an experimental evaluation of the TDS technique. The TDS concept is introduced through a theoretical analysis. The experimental evaluation is carried out using specially designed measurement methods and instrumentation which uses a spectrum analyzer as the central analog signal processing unit. The optimal performance of the TDS measurement systems is analyzed in terms of relevant instrumentation parameters. The advantages and disadvantages of TDS, including practical performance limitations, are discussed, along with the measurement uncertainties of the method. It is shown that TDS in the frequence range covering both underwater acoustics and medical ultrasonics applications offers a viable alternative to other calibration techniques, such as those based on a gated burst measurement system.

Pregnancy-induced hypertension complicated by acute liver disease and disseminated intravascular coagulation. Five case reports.

Five cases of pregnancy-induced hypertension complicated by acute liver disease and DIC are presented. Initial misdiagnosis is described, with appropriate laboratory and histologic documentation of the true condition. Specific therapeutic recommendations are discussed and pathophysiologic mechanisms are suggested.