The number and distribution of intramembrane particles (IMPs) were examined on capped lymphocytes and control cells. Simultaneous movement of surface receptors and microvilli during ...ligand-independent (LI-) cap formation in a hypertonic medium made it possible not only to dis-tinguish between capped and non-capped cells in freeze-fractured specimens but also to detect the region where receptors had accumulated by referring only to their morphology. No accumulation of IMPs in the region of the cap was detected, and the distribution of IMPs was random for both capped and non-capped cells. However, the density of IMPs on the protoplasmic halves of cleaved membranes was slightly, but significantly, lower for capped cells than for non-capped cells, whereas that on the exoplasmic halves did not differ. These results suggest that the majority of IMPs are not composed of mobile receptors such as surface Ig, and surface receptors found as IMPs before cap formation might be changed by this event in the intercalated state into the lipid bilayer and, thus might not be detected as IMPs on cap forming cells.
We have recently demonstrated that the fabrication of SiC bulk ceramics with various atomic ratio of Si:C:O is achieved by pyrolysis and subsequent heat treatment of shaped polycarbosilane (PCS) ...compacts after controlling oxygen content. The procedure is a novel processing route of the combination of polymer precursor techniques, powder technological process and high-temperature material chemistry. This paper deals with the investigation of the effect of the green density and specimen size on the crystallization and densification behavior during the pyrolysis conversion from polymer into ceramic grade. It is reported that the pyrolyzed PCS compact with a higher green density shows a finer microstructure and a smaller pore size.
Serial changes in urinary catecholamine excretion were determined for 17 cockpit crews (6 captains, 6 copilots and 5 flight engineers) of JASDF C-1 aircraft during 10-hour (h) scheduled flights, in ...which captains and copilots performed almost the same flight tasks. The norepinephrine/epinephrine ratio (N/E) in copilots decreased significantly during the flight, whereas little decrease of the N/E was found in captains. Flight engineers showed an intermediate N/E value between captains and copilots. Hormonal responses appeared to correlate with differences in the amount of flying experience of crewmembers. Differences between captains and copilots were more significant when handling the aircraft. Results suggested that flight stresses perceived by crewmembers in the same cockpit were influenced by their flying experience and flight position which could be clearly assessed by determining relative excretions of epinephrine and norepinephrine.
Some of mushrooms have been commonly known as healthful diet. In our efforts to obtain immunologically active low molecular substances from edible mushrooms, a substance was isolated from Agaricus ...bisporus as an effective inhibitor of DNA synthesis in human lymphocytes stimulated with phytohemagglutinin. It was identified with γ-L-glutaminyl-4-hydroxybenzene (γ-GHB) and exhibited low toxicity and 84% inhibition of the human lymphocyte blastgenation induced by phytohemagglutinin at a concentration of 4 μg/ml.
PDF
