Study of the roles of chemical modifiers in determining boron using graphite furnace atomic absorption spectrometry and optimization of the temperature profile during atomization.

The measurement conditions for determining boron using graphite furnace-atomic absorption spectrometry (GF-AAS) were investigated. Differences in the boron absorbance profiles were found using three different commercially available GF-AAS instruments when the graphite atomizers in them were not tuned. The boron absorbances found with and without adjusting the graphite atomizers suggested that achieving an adequate absorbance for the determination of boron requires a sharp temperature profile that overshoots the target temperature during the atomization process.

Regulation of cytokinesis by the formin cdc12p.

For successful cell division, cytokinesis must be properly timed to occur only after the segregation of chromosomes during mitosis. In the fission yeast Schizosaccharomyces pombe, contractile ring assembly initiates at the onset of mitosis, and ring contraction occurs concomitant with septation at the end of anaphase. Although many of the conserved factors necessary for ring assembly and regulation of cytokinesis have been characterized, still little is known about cell-cycle regulation of events that initiate cytokinesis.

Regulation and targeting of the fission yeast formin cdc12p in cytokinesis.

Formins are conserved actin nucleators which promote the assembly of actin filaments for the formation of diverse actin structures. In fission yeast Schizosaccharomyces pombe, the formin cdc12p is required specifically in assembly of the actin-based contractile ring during cytokinesis. Here, using a mutational analysis of cdc12p, we identify regions of cdc12p responsible for ring assembly and localization.

Asymmetric microtubule pushing forces in nuclear centering.

Dynamic properties of microtubules contribute to the establishment of spatial order within cells. In the fission yeast Schizosaccharomyces pombe, interphase cytoplasmic microtubules are organized into antiparallel bundles that attach to the nuclear envelope and are needed to position the nucleus at the geometric center of the cell. Here, we show that after the nucleus is displaced by cell centrifugation, these microtubule bundles efficiently push the nucleus back to the center.

Differential pharmacologic sensitivities of phosphodiesterase-3 inhibitors among human isolated gastroepiploic, internal mammary, and radial arteries.

Unlabelled: Systematic investigations of the actions of phosphodiesterase (PDE)-3 inhibitors on different human vascular tissues have not been performed. We investigated the effects of specific PDE-3 inhibitors (olprinone, milrinone, and amrinone) on contracted human gastroepiploic arteries (n = 70), internal mammary arteries (n = 72), and radial arteries (n = 70) harvested from a total of 134 patients, all of whom were undergoing coronary artery bypass surgery. Each of these PDE-3 inhibitors dose-dependently diminished the contractile responses to 10(-6) mol/L norepinephrine and to either 10(-9) or 10(-8) mol/L of the thromboxane A2 analog U46619.