L5178Y cells were cultured in vitro at various temperatures. When the cells were in the exponential growth phase, the cells were in the "steady state of growth," i.e., the fraction of cells in the G1, S, G2, and M stages and the durations of each stage were constant. The life cycle analysis of the cells in the steady state of growth demonstrated that the G1 stage and the S stage were affected the most by variation of temperature, and suggested that these two stages have considerable influence on the growth rate of the L5178Y cells. The calculated activation energies were positive in each stage of the life cycle, whereas the entropies of activation were negative throughout. The possible significance of these findings in our search for the regulatory mechanisms of cell growth is discussed.Although the effect of temperature on growth rate has been studied in detail in bacteria for many years (15,16,19,36), relatively little work of this nature has been carried out with mammalian cells. If combined with modern techniques of life cycle analysis, such studies in mammalian cells might shed light on the mechanisms regulating cell growth. For example, temperature change could modify cell growth in one of the following ways: (a) the rate of progress through all four stages of the life cycle (G1, S, G2, and M (14, 18)) could be altered to the same degree; (b) the rate of progress through only one or two stages could be affected; and (c) the rates through all four stages could be modified to different degrees resulting in a situation somewhat between (a) and (b). By pinpointing the exact stages in the life cycle where change in temperature or other environmental factors affect the growth rate, it might be possible to identify molecular events occurring simultaneously as the mechanisms involved in the regulation of growth rate.To date, the limited observations of the effect of temperature on cultured mammalian cells are contradictory. In human amnion cells, Sisken (37,38) reported that the main effect of temperature on growth rate is to change the rate of cell passage through the G1 stage. In contrast, Rao and Engelberg (30) observed that temperature change affects the growth rate of HeLa $3 cells by modifying the rate of progress through G1, S, and G2 stages to a similar degree. Although Paul (24) studied the effect of temperature on the growth rate of L5178Y cells, no experimental work combining temperature effect and life cycle analysis has been reported in this cell line.In the present paper, mouse leukemic cells (L5178Y) were incubated at various temperatures and life cycle analyses of cells growing in the exponential growth phase were carried out. The thermodynamics of the rates of progress through the four stages of the life cycle were considered to determine the "energetics" involved in cell growth. An attempt was made to relate these observations to growth regulatory mechanisms.

AcrySof may have a strong tendency to adhere to the lens capsule, contributing to posterior and anterior capsule clarity and preventing lens decentration in vivo.

A superconducting rotating gantry for heavy-ion therapy is being designed. This isocentric rotating gantry can transport heavy ions with the maximum energy of 430 MeV=u to an isocenter with irradiation angles of over 0-360 degrees, and is further capable of performing three-dimensional raster-scanning irradiation. The combined-function superconducting magnets will be employed for the rotating gantry. The superconducting magnets with optimized beam optics allow a compact gantry design with a large scan size at the isocenter; the length and the radius of the gantry will be approximately 13 and 5.5 m, respectively, which are comparable to those for the existing proton gantries. Furthermore, the maximum scan size at the isocenter is calculated to be as large as approximately 200 mm square for heavy-ion beams at the maximum energy of 430 MeV=u. Based on the design of the beam optics, specifications of the superconducting magnets were determined. The superconducting magnets and magnetic-field distributions are designed using a three-dimensional field solver. With the calculated magnetic fields, beam-tracking simulations were performed to verify the design of the superconducting magnets, and concurrently to evaluate the field quality. With calculated beam profiles at the isocenter, we found that the positions of beam spots as well as their size and shape could be well reproduced as designed, proving validity of our design.

No abstract

In seeking the functionality of foodstuffs applicable to medicine, soy sauce was found to show antiplatelet activity. Therefore, the active components in soy sauce were purified, structurally identified, and studied for their inhibitory effects on the aggregation of human platelets. Aqueous 2-fold diluents of soy sauce inhibited platelet aggregation induced by collagen and epinephrine depending on the dilution factor. Since a basic extract with diethyl ether completely inhibited collagen-induced aggregation, it was subjected to serial extractions and multistep HPLC fractionations for purifying antiplatelet components. The finally obtained isolates were identified as 1-methyl-1,2,3,4-tetrahydro-beta-carboline and 1-methyl-beta-carboline on the basis of EI-MS, (1)H NMR, diode array, and fluorescence spectra. Their spectral data and chromatographic behaviors were the same as those of synthetic ones. 1-Methyl-1,2,3, 4-tetrahydro-beta-carboline showed mean concentrations (n = 5-6) of 4.6, 4.2, 28.6, 11.6, and 65.8 microgram/mL to produce 50% inhibition of the maximal aggregation response induced by epinephrine, platelet-activating factor, collagen, adenosine 5'-diphosphate, and thrombin, respectively. Its inhibitory effect was much greater than that of 1-methyl-beta-carboline on platelet aggregation by all the tested inducers. The quantitative HPLC analysis revealed that the significant amounts of both antiplatelet compounds were uniformly contained in commercially available soy sauce. From these results, soy sauce may be referred to as functional seasoning containing alkaloidal components with the potent preventive effect on thrombus formation.