High-performance anion-exchange chromatography of ultraviolet-absorbing constituents of human urine

A 100-μl urine sample was chromatographed on a column packed with a strongly basic macroreticular anion-exchange resin (Diaion CDR-10, 5– μm diameter with a nominal 35% cross linkage). The elution was performed with a linear acetate gradient from 0 to 6.0 M at an average flow-rate of 0.72 ml/min and at an average pressure of 104 kg/cm². The relative standard deviation of retention times and peak height was ± 4% or less. The properties of the macroreticular anion-exchange resin, the effect of the particle size, the pH of acetate buffers, and the effect of the flow-rate of the eluent on the separation were investigated. Thirty three components of urine were then resolved and named.     

Formation of spray-dried powder of S-adenosyl-L-methionine

S-Adenosyl-L -methionine (SAM) is an essential metabolite in all living organisms. In clinical research, SAM has also been suggested as a chemotherapeutic agent in various diseases. The main problem of SAM is its instability at high temperatures, at neutral and alkaline pH, and in the presence of humidity. SAM retention in spray-dried powder was determined under various conditions of spray-drying. The highest SAM retention was obtained when maltodextrin (dextrose equivalent, DE, of 25) was used as the carrier solid with the SAM feed liquid at pH 4.0. The water content in the powder had a significant effect on the stability of SAM. SAM powder with lower water content exhibited higher stability.     

Radial dose distribution for 18.3 MeV/n alpha beams in tissue-equivalent gas

Experimental measurements of the radial restricted linear energy transfer (LETr) for alpha beams of 18.3 MeV/n in tissue-equivalent gas were presented. The radial dose distribution for the alpha beam was deduced from the restricted LET measurements. A differential W value for the alpha particle in the tissue-equivalent gas was also deduced. The result for the differential W value was 29.0 +/- 0.9 eV/ion pair. The radial dose varied according to an inverse-square function with distance from the track center for radii larger than 0.026 micron. The maximum extension of the track, the penumbra radius, as 2.73 +/- 1.67 microns, which was less than predicted by calculations (7-9 microns).     

Quantitative analysis of development of mitochondrial ultrastructure in differentiating mouse hepatocytes during postnatal period

Between birth and 10 days of age, the volume density (volume/unit cytoplasmic volume) of the matrix, and the surface density (area/unit cytoplasmic volume) of the inner membrane and cristae increased in both periportal and perihepatic hepatocytes, and did not differ significantly between the cells of the two zones. After 10 days of age, however, the volume density of the matrix decreased in perihepatic cells and remained unchanged in periportal cells, and, therefore, it became greater in periportal cells than in perihepatic cells in 20-day-old and adult animals. The surface density of the inner membrane and cristae decreased in the cells of both zones. Further, the hepatocyte volume increased markedly, especially in perihepatic zones between 20 days of age and the adult. The results show that, in postnatally differentiating hepatocytes, mitochondria are likely to develop during early postnatal period, then the structural heterogeneity of mitochondria arises, and hepatocyte volume increases markedly during late postnatal period after weaning. Thus, the process of postnatal hepatocyte differentiation includes such several phases of development.     

Heterogeneity and tissue-specific expression of eukaryotic transcription factor S-II-related protein mRNA

Two new cDNA clones for S-II-related proteins were isolated from a mouse liver cDNA library. Analyses of these clones suggested that S-II proteins are a family of proteins with relatively conserved C-terminal regions but variable N-terminal regions, and that some members of this family are expressed in a tissue-specific manner.     

Analysis of Slow Hyperpolarizing Potentials in Frog Taste Cells Induced by Glossopharyngeal Nerve Stimulation

Chemical Senses, 29,     

Measurement of Serine Acetyltransferase Activity in Crude Plant Extracts by a Coupled Assay System Using Cysteine Synthase

Serine acetyltransferase (SATase) (EC 2.3.1.30 [EC] ) catalyzes theformation of Oacetyl-L-serine (OAS) from L-serine in the presenceof acetyl-CoA. A novel assay method was developed for measuringthis enzyme activity in extracts from plant tissues. The assayconsists of a coupled system in which the OAS formed is convertedto cysteine by the addition of cysteine synthase (CSase) (EC4.2.99.8 [EC] ). Cysteine thus formed is determined colorimetricallyand serves as a measure for SATase activity. This method israpid, simple and sensitive, and can be readily adapted formeasurement of SATase activity in crude tissue extracts or homogenates. (Received January 14, 1987; Accepted April 27, 1987)     

Modification in Cell Shape Unrelated to Cellulose Microfibril Orientation in Growing Thallus Cells of Chaetomorpha moniligera

Cellulose microfibril orientation patterns in thallus cellsof Chaetomorpha moniligera were studied, and the relationshipbetween the microfibril and the peripheral microtubule arrangementsduring cell-shape modification by colchicine was examined. Inthe cuttings from growing thalli, linearly arranged cylindricalcells developed into cask-shaped cells during 4–6 daysof culture at 27?C. In the cylindrical cells, microfibrils formingthe innermost portion of the wall were arranged alternatelyin longitudinal and transverse directions, but peripheral microtubuleswere always arranged only in a longitudinal direction. Thesefeatures were also noted in the cask-shaped cells. Colchicineat 10^–3M and 3?10^–3M accelerated both cell expansionand wall thickening with matrix deposition, but the directionsin which both microfibrils and microtubules were arranged werethe same as those of the cylindrical cells. These results indicatethat (1) the microfibril and microtubule arrangements of Chaetomorphaare not necessarily correlated, (2) changes in cell shape ofChaetomorpha are not necessarily accompanied by changes in thearrangement of cell-wall microfibrils, and (3) colchicine playsa role in the loosening and thickening of cell walls by enhancingmatrix deposition. (Received June 2, 1986; Accepted February 13, 1987)     

Estimation of interaction function gamma(x) with sparsely ionizing radiation

The interaction function gamma(chi), which was introduced in the theory of dual radiation action as the probability that two energy transfers separated by distance chi combine with each other to produce a lesion, was estimated with sparsely ionizing radiation (60Co gamma rays and 40 kV X rays). Gamma(chi) was deduced on the assumption that the sensitive matrix is made up of small spherical flocculi distributed over the cell nucleus. The diameter of a flocculus was estimated at (4.0-11.2) X 10(-8) m when the diameter of the cell nucleus d was assumed to be 5 microns, and (4.0-11.4) X 10(-8) m when d was assumed to be 10 microns. It seems reasonable to hypothesize that the flocculus corresponds to the linker DNA in the chromatin structure of DNA, because the size of the linker DNA as a target (about 40 nm) is consistent with the diameter of flocculi obtained in this study.