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Technology.     

Sound-velocity measurements for HFC-134a and HFC-152a with a spherical resonator

A spherical acoustic resonator was developed for measuring sound velocities in the gaseous phase and ideal-gas specific heats for new refrigerants. The radius of the spherical resonator, being about 5 cm, was determined by measuring sound velocities in gaseous argon at temperatures from 273 to 348 K and pressures up to 240 kPa. The measurements of 23 sound velocities in gaseous HFC-134a (1,1,1,2-tetrafluoroethane) at temperatures of 273 and 298 K and pressures from 10 to 250 kPa agree well with the measurements of Goodwin and Moldover. In addition, 92 sound velocities in gaseous HFC-152a (1,1-difluoroethane) with an accuracy of ±0.01% were measured at temperatures from 273 to 348 K and pressures up to 250 kPa. The ideal-gas specific heats as well as the second acoustic virial coefficients have been obtained for both these important alternative refrigerants. The second virial coefficients for HFC-152a derived from the present sound velocity measurements agree extremely well with the reported second virial coefficient values obtained with a Burnett apparatus.Paper dedicated to Professor Joseph Kestin.     

Thieno[2,3-d]pyrimidine-3-acetic acids. A new class of nonpeptide endothelin receptor antagonists

On the basis of structural information for the cyclic hexapeptide endothelin (ET) receptor antagonist, TAK-044, a series of thieno[2,3-d]pyrimidine-2,4-dione derivatives bearing a carboxyl group and aromatic rings that were important for receptor binding were designed, synthesized, and evaluated for ET receptor binding affinities and inhibitory activities against ET-induced vasoconstriction. Optimization of each substituent in the thieno[2,3-d]pyrimidine ring led to the discovery of a novel and potent nonpeptide ET receptor antagonist, 6-(4-methoxymethoxyphenyl)-5-methylsulfonylaminomethyl-1-(2- methylthiobenzyl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]p yrimidine-3- acetic acid (32 g), which binded to human ETA and ETB receptor subtypes with affinities (IC50) of 7.6 and 100 nM, respectively. Compound 32 g effectively antagonized ET-induced vasoconstriction and the inhibitory effect mediated by the ETB receptor was more potent than that of bosentan, while the inhibitory effect mediated by the ETA receptor was slightly less potent than that of bosentan.     

Calcium additional to that bound to the transport sites is required for full activation of the sarcoplasmic reticulum Ca-ATPase from skeletal muscle

The sarcoplasmic reticulum Ca-ATPase is fully activated when approximately 1 microM [Ca2+] saturates the two transport sites; higher [Ca] inhibits the ATPase by competition of Ca-ATP with Mg-ATP as substrates. Here we describe a novel effect of EGTA and other chelators, raising the possibility of an additional activating effect of Ca in the sub- or low microM range. Sarcoplasmic reticulum membranes were isolated from rabbit skeletal muscles. The ATPase activity was measured after incubation at 37 degreesC in 3 mM ATP, 3 mM MgCl2, 50 mM MOPS-Tris (pH 7.2), 100 mM KCl, and variable CaCl2, EGTA and calcimycin. In the absence of added EGTA and Ca the ATPase activity is high due to contaminant Ca. The determination of the ATPase activity in the presence of increasing amounts of EGTA, without added Ca, yields a decreasing sigmoidal function. Ki ranged between 20 and 100 microM, depending on the enzyme concentration. Pi production is linear with time for several [EGTA] yielding suboptimal ATPase activities, which are inhibited by thapsigargin. These suboptimal Ca-ATPase activities are inhibited by preincubation of the enzyme in EGTA, at pH 7.2. This effect increases upon increasing EGTA concentration and preincubation time. The inhibitory effect of the previous exposure of the enzyme to EGTA is partially but significantly reverted by increasing [Ca2+] during incubations. Calcimycin and EDTA have similar effects as EGTA when added in preincubations. The effect of calcimycin is fully reverted by optimal [Ca2+] in incubations. The effects of EGTA, EDTA and calcimycin in preincubation are not additive. The results suggest that an additional calcium, lost during preincubations from a site with affinity near 1 microM, is necessary for full activation of the ATPase.     

Patterns of expression for the mRNA corresponding to the four isoforms of phospholipase Cbeta in mouse brain

Ligand binding to neurotransmitter and hormone receptors which couple to the Gq subclass of GTP-binding protein leads to the activation of phospholipase Cbeta (PLCbeta) which hydrolyses phosphatidyl-inositol 4,5-bisphosphate, yielding a pair of second messengers, diacylglycerol and inositol 1,4,5-trisphosphate (IP3). The expression of PLCbeta1-4 mRNAs was comparatively examined by in situ hybridization in the mouse brain. In adults, PLCbeta1 mRNA was expressed predominantly in the telencephalon, including the cerebral cortex, hippocampus, amygdala, lateral septum and olfactory bulb, with little expression in most thalamic nuclei. PLCbeta2 mRNA was distributed in the white matter, suggesting its expression in non-neuronal cells, most likely oligodendrocytes. PLCbeta3 mRNA was specifically expressed in cerebellar Purkinje cells. The highest levels of PLCbeta4 mRNA were detected in Purkinje cells. High levels of PLCbeta4 mRNA were also found in the thalamus and medial septum, whereas weak signals were detected in most telencephalic regions, thus showing an expression pattern almost reciprocal to that of PLCbeta1 mRNA. During development, such characteristic regional expression of PLCbeta1 and PLCbeta4 were observed starting in late foetal stages, while specific expression of PLCbeta2 and PLCbeta3 appeared in early postnatal stages. We conclude that despite the existence of four PLCbeta isoforms, only one or two of them is expressed in individual neurons and glial cells. The distinct expression of PLCbetas provides a molecular basis for analysing the nature of the specific signal transduction pathway leading to the production of diacylglycerol and IP3 in distinct cell types and in different regions of the brain.     

A flexible random allocation program for multi-institutional clinical trials

This paper describes a flexible random allocation program that assigns treatments to patients according to their prognostic factors in multi-institutional clinical trials. The source lists are available in the appendix of this paper. This program is based on Pocock and Simon's minimization method and Zelen's method for institution balancing. The numbers of institutions, treatments, and prognostic factors can be set arbitrarily. The maximum number of institutions, treatments, or prognostic factors that can be accommodated by the program is limited only by the size of the main memory. For example, an IBM-PC with a 640KB main memory can run a program of 1500 institutions, 4 treatments and 20 prognostic factors.     

Extrathymic differentiation of resident T cells in the joints of mice with collagen-induced arthritis

Murine collagen-induced arthritis (CIA) is known as a T cell-mediated autoimmune disease, although autoantibodies are also suspected to be associated with the onset of the disease. To determine the origin of such T cells in the joints of mice with CIA, their phenotypic properties as well as those of T cells in other immune organs were examined in DBA/1 mice. Since a significant number of mononuclear cells (MNC) was also yielded by the joints of normal DBA/1 mice, the properties of these T cells were examined in parallel. When CIA was induced by an intradermal injection of type II collagen at the base of the tail, the numbers of MNC yielded by the regional lymph nodes and the foot joints were doubled. Interestingly, regardless of the onset of CIA, the joints were always comprised of unique T cell populations, including IL-2(R)alpha- beta+ T cells, gammadelta T cells, CD8alpha+ beta- cells, and CD44+ L-selectin- cells. All these properties coincide with those of extrathymic T cells in liver and intestine. In the case of gammadelta T cells in joints, Vgamma and Vdelta usages were unique and different from those in the other organs. More importantly, Vgamma and Vdelta usages in gammadelta T cells in the joints of normal mice and in those of mice with CIA were essentially the same. Taken together with the expression of recombination-activating gene-1 and -2 mRNAs by MNC in mice with CIA, these findings raise the possibility that the joints have their own resident T cells that are extrathymically generated in situ.     

Theoretical and measured characteristics of metal(CoSi2)-insulator(CaF2) resonant tunnelingtransistors and the influence of parasitic elements

We report on the theoretical and measured characteristics of triple-barrier metal (CoSi₂)-insulator(CaF₂) (M-I) resonant tunneling transistors (RTT) grown on an n-Si(111) substrate, and the influence of their parasitic elements on the measured characteristics. First, we analyze theoretical characteristics of an M-I RTT, and then show fabrication process and current-voltage (I-V) characteristics obtained at 77 K, in which several degradations are observed: large resonance voltage, low peak-to-valley (P-V) ratios at negative differential resistance (NDR), and reverse base current. Analysis, taking several parasitic elements (e.g., base resistance, substrate resistance and leakage currents connected to the intrinsic transistor) into account, explains observed characteristics well. Finally, we show the first transistor action with large P-V ratios at 300 K, which is achieved by reducing collector-emitter leakage currents     

A case of carcinomatous peritonitis for which combination therapy of 5-FU, leucovorin and cisplatin was effective

This case report describes a case of carcinomatous peritonitis which showed a good response to the combination therapy of 5-FU, leucovorin and cisplatin. A 55-year-old man was admitted with complaints of meteorism due to ascites fluid. Ascitic examination showed a high concentration of CEA and CA19-9, and adenocarcinoma cells. Laboratory and radiological examination did not reveal the origin of the carcinoma, and laparotomy suggested an appendiceal origin. The combination chemotherapy with 5-FU, leucovorin and cisplatin was conducted for a total of 11 courses for 2 years with good QOL until his death. This therapy was suggested to be useful for inoperable carcinomatous peritonitis.