In recent TV-based image cytometers considerable disproportionalities exist between the IOD values of reference cells, as well as diploid, tetraploid, and octoploid analysis cells compared with their ...theoretical IOD ratios. An important source of these deviations is the limited spatial resolution of the microscopic objectives, based on the effects of diffraction. Compared to these influences the glare is less important. A correcting method is given for reducing both effects on the DNA measurements, which considers a narrow region along the nuclear contour to be optically disturbed. The correction of this mean optical density (MOD)- and size-dependent geometric resolution error is applicable to any cell type. The method was tested on 25 rat liver imprints and 29 fine needle aspirates from breast cancers. The resulting stemline ratios are close to the theoretical ones. A further improvement was then reached by a glare correction. The slide-by-slide variations of stemline ratios, remaining after the corrections, were considered in a test statistic for defining the aneuploidy of a given stemline. Statistically based clear-cut decision rules were obtained for DNA histogram interpretation.
The pharmacokinetics and bioavailability of mephobarbital have been studied in 2 volunteers. Plasma levels of mephobarbital and phenobarbital were measured by gas chromatography-mass spectroscopy ...with selected ion monitoring. Urinary output of phenobarbital and the p-hydroxy derivatives of both mephobarbital and phenobarbital was measured by high pressure liquid chromatography. The time course of these plasma and urinary levels was monitored following single 800-mg oral and 200-mg intravenous doses in the 2 patients. The major conclusions of the study were that mephobarbital is reasonably well absorbed following oral dosing and that some 35% or so of the dose (by either route) is converted to the recently identified metabolite, p-hydroxymephobarbital.
PDF