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AbstractWe screened for factors upregulating glial fibrillary acidic protein (GFAP) promoter activity by functional cloning with an immature astrocyte cell line (HB108-10) harboring a GFAP-lacZ construct. One cDNA clone that repeatedly upregulated lacZ expression encoded cystatin C (CysC), a cysteine protease inhibitor. TGF-β induced CysC and GFAP expression in AP-16 cells, an astrocyte progenitor-like cell line expressing GLAST (a glutamate transporter subtype specifically expressed in immature astrocytes). CysC gene expression started earlier than that of GFAP in the mouse forebrain. It started in the ventricular zone at a similar period as (or slightly after) GLAST expression, but before GFAP expression. Although previous data showed that CysC is involved in the maintenance of adult neural stem cells, our data indicate that it is involved in astrocyte differentiation during mouse brain development.Copyright © 2004 S. Karger AG, Basel

Local structures and motions of radical reactants in highly selective tunneling abstraction reaction in neopentane−ethane mixture are investigated with CW-ESR, ENDOR, and ESEEM spectroscopy at different temperatures. H atoms produced by the radiolysis of neo-C5H12 in the neo-C5H12−C2H6 (2 mol %) mixtures above 40 K react selectively with the solute C2H6 to give ethyl radicals. The selective reaction is suppressed below 30 K. The local structures of neopentane matrix around neopentyl and ethyl radicals are approximately the same in the temperature range from 4.4 to 45 K. Although neopentyl radicals are rigidly trapped below 100 K, ethyl radicals in neopentane matrix begin to librate even at 6 K and increase the degree of motion up to 30 K. Finally, the librating motion of the ethyl radicals in neopentane matrix is vigorous above 40 K. The ethane molecule can take more favorable orientation for the hydrogen abstraction reaction by H atoms than rigid neopentane molecules by the vigorous libration motion, resulting in the selective reaction with H atoms.

H atoms produced by the γ-ray irradiation of solid para-H2 (p-H2) and solid normal-H2 (n-H2) decay gradually when the irradiated sample is stored at 4.2 K. ortho-H2 (o-H2) molecules at the sites nearest an H atom in solid n-H2 convert to p-H2 molecules by interacting with the H atom. H atoms in solid H2 decay by the process of tunneling diffusion H + p-H2 → p-H2 + H and finally recombine with other H atoms. The rate constants for the tunneling reaction were obtained from the decay rates of H atoms in solid H2 at various concentrations of o-H2. When solid n-H2 is stored for 10 h at 4.2 K after γ-ray irradiation, a number of o-H2 molecules change into p-H2 molecules by a catalytic chain reaction induced by mobile H atoms. The G value of the o-H2 yields from H atoms amounts to 1−2.6 × 10⁴. The rate constant for the tunneling reaction H + p-H2 → p-H2 + H decreases drastically with increasing numbers of o-H2 molecules, which exist as orientational defects in solid p-H2. It was concluded that a very small amount of energy (ca. 2 cal mol^-1) affects the tunneling reaction at very low temperatures.

The protective effect of piperacillin against the nephrotoxicity of cisplatin was compared with that of fosfomycin in Fischer 344 rats. Blood urea nitrogen, serum creatinine, and morphological changes were evaluated as the renal toxicological parameters. Rats receiving 2 mg of cisplatin per kg of body weight for 5 days showed significant (P less than 0.01 by multiple-comparison test) elevation of blood urea nitrogen and serum creatinine concentrations compared with rats receiving saline alone and also exhibited development of cell lesions in the pars recta of the tubules in the outer stripe of the outer medulla. However, piperacillin (250 and 1,000 mg/kg) significantly (P less than 0.01 by multiple-comparison test) reduced these toxicological parameters in comparison with results for cisplatin alone. The protective effect of piperacillin was superior to that of fosfomycin, although platinum levels in the kidney were higher with the combination of cisplatin and piperacillin than with cisplatin plus fosfomycin. Although the nephrotoxicity of cisplatin was also reduced when cisplatin was administered concomitantly with sodium chloride in mole-equivalents to 250 and 1,000 mg of piperacillin per kg, its protective effect was less than that of the corresponding piperacillin dose. These results suggest that piperacillin may have a role as a protective agent against the nephrotoxicity of cisplatin.

Measurements were made of the rate of natural evaporation into a stagnant argon or helium atmosphere from a rectangular-shaped surface of liquid sodium placed on the bottom floor of an evaporation test box. The tests were carried out at various levels of sodium temperature and inert gas pressure under conditions where mist formation could be expected. The values obtained as the Sherwood number were compared with those predicted by various theoretical models. The overall results revealed that the enhancement of evaporation brought about by mist formation significantly increased as the sodium temperature did. It was concluded that the previous theoretical models were not adequate for obtaining correct values for the evaporation rate.

The antithrombotic action of thrombomodulin was studied in mice. Rat and mouse thrombomodulin were isolated from lung acetone powders, and anti-rat thrombomodulin antibodies were prepared in rabbits. The antibodies neutralized both mouse (Kd approximately 150 nM) and rat thrombomodulin (Kd approximately 50 nM). A role for thrombomodulin in vivo was shown in mice injected intravenously (IV) with thrombin. All mice injected with 15 U thrombin (bolus) died of thromboembolism (mean survival 55 minutes), whereas those injected with a lower dosage survived. Prior injection with anti-rat thrombomodulin (1.8 mg IgG/mouse) potentiated the lethal effects of subsequent thrombin, whereas injection of thrombomodulin (isolated from mouse lung) prior to thrombin prolonged survival in a thrombomodulin concentration-dependent manner. The protective effect of thrombomodulin persisted for 30 minutes but after one hour thrombin injection was as toxic as in control animals. The half life (t1/2) for plasma clearance of 125I- mouse lung thrombomodulin was nine minutes. The major site of clearance was the liver, although thrombomodulin accumulated in several organs ten minutes after injection. The mechanism by which antithrombomodulin antibodies potentiated the lethal effects of thrombin was studied by measuring the protein C activating cofactor activity on vena cava removed from animals injected with antibodies. Protein C activation was inhibited by antibodies, suggesting a role for activated protein C in prevention of lethal thromboembolism. We found no effect of antibodies on the clearance of thrombin from mouse plasma, suggesting that blockade of endothelial endocytosis of thrombin does not play a significant role in the effects of antibodies. These results indicate that thrombomodulin participates in the defense against thrombosis in vivo.

Decay processes of H2^- anions in γ-ray-irradiated solid parahydrogen were studied by using an ESR spectrometer. The following interesting results were obtained. First, the initial yields of ortho-H2^- anions in the γ-irradiated solid parahydrogen were 3 times as large as those of para-H2^- anions. Second, the yields of para-H2^- anions decrease faster than those of ortho-H2^- anions upon storage of the irradiated samples at 4.2 K. Third, the decay rate of H2^- anions is accelerated by the addition of HD and D2 molecules. Fourth, H2^- anions at 2.2 K decay faster than at 4.2 K. According to the parity conservation rule in a homonuclear diatomic molecule, the energy of ortho-H2^- anions at the ground state is lower than that of para-H2^- anions, whereas that of ortho-H2 molecules is higher than that of para-H2 molecules at low temperatures. The first and second results are ascribed to para → ortho conversion of H2^- anions. The third result indicates that nearby HD and D2 accelerate the decay of H2^- anion or broaden the spectra by superhyperfine interactions. The fourth result suggests a coherent tunneling mechanism of decay of H2^- anions in the solid parahydrogen.

When H atoms are produced by the photolysis of HI or the radiolysis of neo-C5H12 in the neo-C5H12−i-C4H10(2 mol %) mixtures above 40 K, the H atoms react selectively with the solute i-C4H10. The selective reaction is suppressed below 30 K. The reactions have been studied by electron spin resonance and electron spin echo measurements at 4−100 K. The drastic temperature effect on the reaction by H atoms suggests that the H atoms concerned are not hot atoms, but thermal atoms. The thermal H atoms react with the solute alkane by quantum tunneling at low temperature. Temperature effects on the ESR spectra and the spin−lattice relaxation times of the solvent neo-C5H11 radicals and the solute t-C4H9 radicals indicate that local motions of the solute i-C4H10 molecules take place above 40 K, while motions of the solvent neo-C5H12 molecules are severely restricted even at 100 K. It is concluded that the local motions of the solute i-C4H10 assist the tunneling abstraction reaction by H atoms, resulting in the selective reaction with the solute above 40 K.

The abstraction reactions, T + HD(DH) → HT(DT) + D(H) and T + H2(D2) → HT(DT) + H(D) were studied experimentally in liquid ³He−⁴He media at 1.3 K and theoretically using the gas-phase reaction model. The experimental reaction system has two characteristics; one is that the tritium atom (T) is produced from one of the constituents, ³He, through ³He(n, p)T nuclear reaction, and the other is that superfluid or normal-fluid reaction medium can be chosen arbitrarily by changing the composition and temperature of the sample. The experimental isotope effect defined by {[HT]/[H2]}/{[DT]/[D2]} for the reactions T + H2(D2) → HT(DT) + H(D) was found to be 158 in superfluid and 146 in normal-fluid solutions. The large isotope effects observed were qualitatively explained via quantum mechanical tunneling on the basis of the theoretical calculations of thermal rate constants for these reactions. In the T + HD(DH) → HT(DT) + D(H) reactions, the experimental isotope effect was <19.8. From the considerations on both the reaction processes based on the experimental results and the theoretical calculations, it has been suggested that the quantum mechanical tunneling abstraction through van der Waals complex plays a predominant role for both the reactions.

The magnetization M for (Cr 1- x Ni x ) 2 As with x =0.5 and 0.7 has been measured as a function of magnetic field H up to 36 T in the temperature ( T ) range 1.3 K ≤ T ≤ 210 K. In (Cr 0.5 Ni 0.5 ) 2 As, M against H at 77 and 130 K tends to saturate above about 2 T, while at 210 K it gradually increases. No spontaneous magnetization is observed in the temperature range down to 1.3 K in (Cr 0.3 Ni 0.7 ) 2 As. In this sample, an abrupt increase in M against H accompanying a hysteresis loop is observed at lower temperatures and low H range. The magnitude of hysteresis loop decreases with increasing T up to about 10 K, while the increasing behavior of M is maintained up to about 40 K. The obtained results are briefly discussed from the viewpoint of band magnetism.

Thrombomodulin is an endothelial membrane anticoagulant protein that is a cofactor for protein C activation. We have evaluated the expression of thrombomodulin in cultured mouse hemangioma cells before and after treatment with phorbol myristate acetate (PMA), an agent that stimulates protein kinase C. We also isolated a cDNA encoding 481 amino acids of mouse thrombomodulin and the entire 3'-untranslated portion of its mRNA. The deduced amino acid sequence of mouse thrombomodulin is similar to those determined for human and bovine thrombomodulin. An S1 nuclease protection assay was used to measure thrombomodulin mRNA in hemangioma cells. The half-life for thrombomodulin mRNA was 8.9 +/- 1.8 h (S.D.) in cells treated with actinomycin D. Treatment with PMA had no effect on thrombomodulin mRNA levels. Thrombomodulin turnover was evaluated by immunoprecipitation of [35S]methionine-labeled thrombomodulin. The t1/2 was 19.8 +/- 3.9 h (S.D.); PMA treatment decreased the t1/2 to 10.9 +/- 1.1 h (S.D.) while increasing the rate of synthesis to a maximum of 190% of control. Protein C cofactor activity on hemangioma cells was reduced 35 +/- 4% by treatment with PMA within 30 min. This decrease was associated with a parallel decline in cell surface thrombomodulin antigen and with enhanced phosphorylation of thrombomodulin on serine residues. We conclude that thrombomodulin is phosphorylated in response to treatment of hemangioma cells with PMA which leads to decreased protein C cofactor activity and both increased degradation and synthesis of thrombomodulin.

A method has been proposed for measuring local heat transfer coefficients. The method uses the change of a wet surface temperature by radiation heating and can be applied to isothermal conditions and with large variations of the local heat transfer coefficients along the surface of a body. The present method is based on the heat balance equation, which expresses a simple relationship between humidity and wet-bulb temperatures. An experiment was devised to measure the local heat transfer coefficient along a flat plate. The results confirmed the effectiveness of the present method to measure local and overall heat and mass transfer coefficients with reasonable accuracy.

Some of the previously reported heat transfer coefficients with evaporation are fairly large as compared with those of a dry body under similar hydrodynamic conditions. In order to clarify this curious enhancement of heat transfer, a method of error evaluation was developed and applied to correct the experimental errors in the recently reported results. An experimental study was also made on turbulent heat and mass transfer of air flowing over a water surface. The present and the previously reported experimental results revealed that the heat transfer coefficient with evaporation agrees with that of a dry body without evaporation, within experimental error, if the erroneous heat inputs into the liquid are properly corrected according to the proposed method.

The flux state of the organic superconductor κ-(BEDT-TTF)2Cu(NCS)2 has been investigated by ultrasonic measurements. The magnetic field dependence in the longitudinal sound velocity, shows a remarkable dip. The amount of the dip is proportional to cosϕ, where ϕ is the angle between the propagation direction of the sound and the magnetic field. The magnetoresistance anomaly in this salt, which is seen in the same magnetic field range as for the sound velocity, has been interpreted by the thermal fluctuation of the Josephson coupling between the superconducting layers. The sound velocity anomaly is interpreted by this mechanism. It would be concluded that such anomaly is caused by a large Grüneisen parameter in this salt.

The protective effect of piperacillin against the nephrotoxicity of cephaloridine and gentamicin was examined in experimental animals. In rabbits, piperacillin was infused at a dose of 1 mg/kg (body weight) per min over 225 min and cephaloridine (300 mg/kg) was intravenously administered as a bolus 45 min after the start of a drip infusion. Blood urea nitrogen, serum creatinine, and N-acetyl-beta-D-glucosaminidase (NAG) in urine were measured as the renal toxicological parameters before and 24 h after cephaloridine dosing. Although the single administration of cephaloridine significantly elevated these parameters, the elevation was prevented by the concomitant administration of piperacillin. The protective effect of piperacillin was superior to those of cephalothin and fosfomycin. In rats, piperacillin (1,000 mg/kg) was intravenously administered and immediately followed by the intramuscular administration of gentamicin (100 mg/kg) every 24 h for 5 days. When piperacillin was concomitantly administered with gentamicin, the elevations of blood urea nitrogen, serum creatinine, and urinary NAG were significantly lower than when gentamicin was given alone. The concomitant administration of piperacillin resulted in a significant protective effect against the nephrotoxicity of cephaloridine in rabbits and of gentamicin in rats. Histopathological observation also supported the protective effect of piperacillin. The protective mechanism of piperacillin might be the inhibition of transport from the peritubular side to tubular cells for cephaloridine and from both the peritubular and luminal sides for gentamicin.

We present experimental observations and study of $${\text{H}}_{\text{2}}^ - $$ in solid parahydrogen. Since the parahydrogen molecule does not produce local magnetic fields, high–resolution ESR spectra of trapped radicals can be observed in the solid parahydrogen matrices. Using this high–resolution ESR spectroscopy, new quartet ESR signals were observed in γ–rays irradiated solid parahydrogen and assigned as $${\text{H}}_{\text{2}}^ - $$ In addition, para– $${\text{H}}_{\text{2}}^ - $$ was observed to convert into ortho– $${\text{H}}_{\text{2}}^ - $$ on the storage at 4.2 K. On the other hand, ortho–H2molecule converts into para– $${\text{H}}_{\text{2}}^ - $$ at cryogenic temperatures. The difference in the conversion between the H2molecule and the $${\text{H}}_{\text{2}}^ - $$ anion is explained by the parity conservation law of wavefunctions on exchanging the protons in homonuclear diatomic molecules such as the $${\text{H}}_{\text{2}}^ - $$ anion and H2molecule.

We have measured mRNA levels for thrombomodulin, an endothelial membrane cofactor for the activation of protein C by thrombin, in a mouse hemangioma cell line. Cycloheximide, an inhibitor of protein synthesis, increased levels of thrombomodulin mRNA, as measured in an S1 nuclease protection assay, to 2.5-4.0 times control levels. Thrombomodulin transcription in response to cycloheximide treatment, as determined by nuclear run-on analysis, was 3.9 +/- 1.3 (mean +/- SD) times that found in untreated cells. Thrombin also increased thrombomodulin mRNA levels to 151 +/- 21% (mean +/- SD) of control levels after 2 hr. Transcription increased in response to thrombin by 2.1- to 7.3-fold. The combination of thrombin and cycloheximide had no additive effect on thrombomodulin mRNA levels. Thrombin treatment of hemangioma cells also caused an increase in thrombomodulin protein synthesis to 142 +/- 17% (mean +/- SD) of control levels as determined by immunoprecipitation of [32S]methionine-labeled thrombomodulin. We conclude that thrombomodulin expression is determined in part by the rate of transcription and that thrombomodulin mRNA levels in hemangioma cells are increased by treatment with cycloheximide or thrombin. The increased transcription in response to cycloheximide suggests the existence of a labile protein repressor of thrombomodulin transcription.

The resistance mechanisms of more than 2,000 aminoglycoside-resistant gram-negative aerobic bacteria were estimated by a method that assigned a biochemical mechanism based on susceptibility to selected aminoglycosides. Strains from hospitals in Japan, Formosa, and Korea (the Far East) were compared with strains from Chile and the United States. Of the strains from Chile, 90% had an aminoglycoside resistance pattern indicative of the 3-N-acetyltransferase [AAC(3)-V] enzyme. Of the strains from the Far East, 78% had susceptibility patterns suggesting the presence of AAC(6') enzymes. In contrast, strains from the United States had a wider variety of resistance mechanisms including 2''-O-adenylyltidyltransferase [ANT(2'')], AAC(3), AAC(6'), and AAC(2'). Reflecting these differences in resistance patterns, the frequencies of resistance to gentamicin, tobramycin, dibekacin, and amikacin in strains from the United States were different from those in strains from the Far East. These differences seem to be correlated with different aminoglycoside usage in the two regions. In the United States, where gentamicin was the most widely used aminoglycoside, 92% of the strains were resistant to gentamicin, 81% were resistant to dibekacin, and 8.8% were resistant to amikacin. In the Far East, dibekacin and kanamycin were widely used in the past and more recently amikacin has been frequently used. Of the strains from this region, 99% were resistant to dibekacin, 85% were resistant to gentamicin, and 35% were resistant to amikacin.