Mutually opposite effects of dopamine.HCl and chlorpromazine. HCl on the thickness of liposomal lipid bilayers.

The aim of this study was to provide a basis for examining the molecular mechanism for the pharmacological action of dopamine.HCl (DA) and chlorpromazin.HCl (CPZ). Radiationless energy transfer from the surface fluorescent probe, 1-anilinonaphthalene-8-sulfonic acid, to the hydrophobic fluorescent probe, bispyrenylpropane (Py-Py), was used to examine the effects of DA and CPZ on the thickness (D) of the liposomal lipid bilayers prepared with total lipids (SPMVTL) and phospholipids (SPMVPL) extracted from neuronal membranes. The thickness (D) of intact SPMVTL and SPMVPL (37 degrees C, pH 7.4) were 0.914 +/- 0.010 and 0.886 +/- 0.009 (arbitrary units, n = 5), respectively. DA decreased the thickness of both SPMVTL and SPMVPL in a dose-dependent manner with a significant decrease in thickness observed even at 40 x 10(-9) M and 40 x 10(-9) M, respectively. On the other hand, CPZ increased the thickness of both SPMVTL and SPMVPL in a dose-dependent manner with a significant increase in thickness observed even at 35 x 10(-5) M and 35 x 10(-5) M, respectively. The sensitivities to the decreasing and increasing effect of the membrane lipid bilayers thickness by DA and CPZ, respectively, differed according to the liposomes in descending order of SPMVPL and SPMVTL. The decreasing and increasing action of DA and CPZ, respectively, on the membrane thickness had many effects that may be responsible for the dopaminergic receptor-DA and -CPZ interaction as well as the protein-lipid interaction.

Defect study on polyaniline by positron annihilation spectrometry.

Fast coincidence system was constructed and applied to positron annihilation spectrometry (PAS). We studied on the factors that affected the time resolution of the system. Time resolutions were obtained and mutually compared with respect to several factors such as sizes, kinds of scintillators, length dependence of delay lines on the CFD583, and width variations of the windows for 511keV and 1.27MeV. Monoenergetic positron acceleration system was used to measure the lifetime components for the polyaniline, which have variable electric conductivity. We obtained 360-380ps as bulk lifetime for polyaniline, which intended to show that the higher the conductivity, the longer the bulk lifetime. The reasons were discussed in the context of the protonate H(+). The defect in the sample was discussed in the relation of positron lifetime corresponding to the variation of conductivity.

Compact soft x-ray transmission microscopy with sub-50 nm spatial resolution.

In this paper, the development of compact transmission soft x-ray microscopy (XM) with sub-50 nm spatial resolution for biomedical applications is described. The compact transmission soft x-ray microscope operates at lambda = 2.88 nm (430 eV) and is based on a tabletop regenerative x-ray source in combination with a tandem ellipsoidal condenser mirror for sample illumination, an objective micro zone plate and a thinned back-illuminated charge coupled device to record an x-ray image. The new, compact x-ray microscope system requires the fabrication of proper x-ray optical devices in order to obtain high-quality images. For an application-oriented microscope, the alignment procedure is fully automated via computer control through a graphic user interface. In imaging studies using our compact XM system, a gold mesh image was obtained with 45 nm resolution at x580 magnification and 1 min exposure. Images of a biological sample (Coscinodiscus oculoides) were recorded.