Polyol pathway, 2,3-diphosphoglycerate in erythrocytes and diabetic neuropathy in rats

Despite substantial data on radioligand binding to the sigma receptor, neither the physiologic function nor the intracellular mechanism of this receptor is known. In this study, we examined the effect of sigma ligands on Ca++ influx induced by N-methyl-D-aspartate (NMDA) in single primary cultured rat frontal cortical neurons with fluorescence video microscopy. All sigma ligands tested reduced the NMDA-induced increase in intracellular Ca++ concentration ([Ca++]i) in a dose-dependent manner with IC50 values in the low micromolar range. Inhibition by haloperidol and (+)-N-cyclopropylmethyl-N-methyl-1,4-diphenyl-1-ethyl-but-3-en-1-ylam ine hydrochloride (JO1784) was noncompetitive; but, exogenous glycine (100 microM) did not alter their IC50 values. In addition, haloperidol (1 microM) enhanced Mg+(+)-mediated inhibition of the NMDA-induced [Ca++]i increase (IC50 = 0.45 +/- 0.01 mM vs. an IC50 = 0.98 +/- 0.06 mM for Mg++ alone). Selective sigma receptor ligands (JO1784, (+)-pentazocine) caused a greater reduction of the sustained phase of the Ca++ response to NMDA, whereas haloperidol and DTG reduced both the initial and sustained phase of the response to a similar degree. The rank order of potencies for inhibition of both the sustained Ca++ response phase and (+)-[3H]SKF-10047 binding (Roman et al., J. Pharm. Pharmacol. 42: 439-440, 1989) were similar. These findings suggest that sigma 1 ligands indirectly modulate NMDA receptor complex function through sigma 1 receptors and that sigma ligands facilitate the desensitization of the Ca++ response to NMDA.     

Scale effect of the testing furnaces on the oxidation of silicon carbide ceramics

Journal of Materials Science Letters -     

Studies on the constituents of Calliandra anomala (Kunth) Macbr. I. Structure elucidation of two acylated triterpenoidal saponins

Two novel triterpenoidal saponins, called calliandra saponins A and E, were isolated from the branches of Calliandra anomala (Kunth) Macbr. On the basis of the chemical and physiocochemical evidence, their structures were defined as 3-O-alpha-L-arabinopyranosyl-(1-->2)-alpha-L-arabinopyranosyl++ +-(1-->6)-2- acetamido-2-deoxy-beta-D-glucopyranosyl echinocystic acid 28-O-(beta-D-glucopyranosyl-(1-->3)-[beta-D-xylopyranosyl-(1-->3)-beta-D - xylopyranosyl-(1-->4)]-alpha-L-rhamnopyranosyl-(1-->2)-[(6S)-2-trans- 2,6-dimethyl-6-O-beta-D-xylopyranosyl-2,7-octadienoyl-(1-->6)]-bet a-D- glucopyranosyl) ester (4) and 3-O-alpha-L-arabinopyranosyl-(1-->2)-alpha-L-arabinopyranosyl++ +-(1-->6)-2- acetamido-2-deoxy-beta-D-glucopyranosyl echinocystic acid 28-O-[beta-D-glucopyranosyl-(1-->3)-[beta-D-xylopyranosyl-(1-->3)-beta-D - xylopyranosyl-(1-->4)]-alpha-L-rhamnopyranosyl-(1-->2)-[(6'S)-2'-trans- 2',6'-dimethyl-6'-O-(2-O-(6S)-2-trans-2,6-dimethyl-6-hydroxy-2,7-octa dienoyl)- beta-D-xylopyranosyl-2',7'-octadienoyl-(1-->6)]-beta-D-glucopyr ano syl] ester (5), respectively.     

Enhancement of cytosine arabinoside cytotoxicity by granulocyte/macrophage colony-stimulating factor and granulocyte colony-stimulating factor in a human myeloblastic leukemia cell line

Enhancement of the cytotoxicity of cytosine arabinoside (ara-C) by granulocyte/macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF), and the mechanisms involved, were studied in the AML-193 human leukemia cell line. AML-193 cells require GM-CSF and G-CSF(CSFs) for optimum growth, and 24 h deprivation of CSFs decreased DNA synthesis measured in terms of 3H-thymidine incorporation. The DNA synthesis gradually recovered upon addition of CSFs. To examine the sensitivity to ara-C under different growth conditions, two groups of cell suspensions, one pretreated with CSFs after 24 h deprivation (CSFs(+) cells), and the other held continuously under CSFs-free conditions (CSFs(-) cells), were exposed to 1.0 microgram/ml of ara-C for 16 h. In clonogenic assays, CSFs(+) cells showed higher sensitivity to ara-C than CSFs(-) cells. These cell groups showed no significant difference in ara-C triphosphate accumulation or retention, though the amount of ara-C incorporated into the acid-insoluble fraction was two times greater in CSFs(+) cells than CSFs(-) cells, and that difference became even clearer in the retention pools. These data suggest that the enhancement of cytotoxicity by CSFs was due to the promotion of ara-C incorporation into DNA as a result of an increase of the cell fraction in the S phase.     

Possibilities of perpendicular magnetic recording

The potential of perpendicular magnetic recording using a single-pole head and a double-layered medium has been investigated theoretically by computer analysis and compared with that of longitudinal magnetic recording. In conventional longitudinal recording, a recording demagnetizing loss due to the change of magnetization mode from semicircular to circular shapes occurs with increasing recording level at high bit density. In perpendicular magnetic recording, the perpendicular magnetization mode is maintained regardless of recording level even at an extremely high bit density of 571 kFRPI. This indicates that the perpendicular recording medium has a very high recording resolution, where a single bit size approaches several diameters of the microcrystalline particles of the Co-Cr layer. An ultrahigh density at which the recording area for 1 bit will reach 1 μ² at present and 500 Å₂ in future should be possible     

High-speed operation of 1.5 μm GaInAsP/InP optoelectronicintegrated laser drivers

A 1.5 μm-wavelength high-speed self-aligned constricted-mesa laser diode and an InP MESFET have been integrated monolithically without deterioration in the performance of either device, by using a gate projection process. A broad 3 dB bandwidth of 6.6 GHz was demonstrated for the first time     

Fractional transformation group induced byQR factorization and linear prediction problem

A new fractional transformation group is found which acts transitively on the space of linear predictors for nonstationary processes by using the QR factorization of nonsingular matrices.     

Effect of herbimycin A on renal cancer cell growth

We investigated the effect of herbimycin A on the monolayer growth of 4 human renal cell carcinoma (RCC) cell lines and a normal renal tubular cell line (RTC 13) using MTT [3-(4,5-dimethylthiszol-2,5-diphenyl tetrazolium bromide)] assay. Herbimycin A induced remarkable growth inhibition in each RCC cell line tested, without any morphological changes of the cells. At the concentration of 500 ng/ml, herbimycin A caused more than a 30% growth inhibition in all RCC cells (p < 0.005 vs RTC 13), while less than 7% growth inhibition was observed in RTC 13 at the same herbimycin A concentration. The cell cycle was estimated by analysing DNA (deoxyribonucleic acid) content using a FACS. A DNA histogram of RCC cells treated at herbimycin A showed a block in the cell cycle at the S and G2M phases. However, little effect by herbimycin A on RTC 13 cells was observed. Our results suggest that protein tyrosine kinases inhibitors, like herbimycin A, may offer a new treatment option for RCC patients.     

Nuclear relaxation in the superconducting state of (MDT-TTF)2AuI2

We report the results of our attempt to measure the proton nuclear relaxation rate, 1/T ₁, in the superconducting state of the title material. The relaxation rate in the superconducting state at a field of 1 T was found much longer than that in the normal state, but it became clear that the dominant contribution came from the normal core region. The nuclear relaxation at zero field was examined by using the field cycling technique. An ln(t) term in the relaxation curve was observed at low temperatures, suggesting the contribution of the creeping motion of vortices. We discuss the possibility to determine the intrinsic temperature dependence of 1/T ₁ in the superconducting state.     

Inhibition of osteoblastic cell differentiation by conditioned medium derived from the human prostatic cancer cell line PC-3 in vitro

Human prostatic carcinoma frequently metastasizes to bone tissue and activates bone metabolism, especially bone formation, at the site of metastasis. It has been reported that an extract of prostatic carcinoma and conditioned medium (CM) of a human prostatic carcinoma cell line, PC-3, established from a bone metastastic lesion, stimulate osteoblastic cell proliferation. However, there is little information about the effect of PC-3 CM on the differentiation of osteoblastic cells. In this study, we investigated the effect of PC-3 CM on the differentiation of two types of osteoblastic cells, primary fetal rat calvaria (RC) cells containing many undifferentiated osteoprogenitor cells, and ROS 17/2.8, a well-differentiated rat osteosarcoma cell line. PC-3 CM inhibited bone nodule formation and the activity of alkaline phosphatase (ALPase), an osteoblastic marker enzyme, on days 7, 14, and 21 (RC cells) or 3, 6, and 9 (ROS 17/2.8 cells) in a dose-dependent manner (5-30% CM). However, the CM did not affect cell proliferation or cell viability. PC-3 CM was found to markedly block the gene expression of ALPase and osteocalcin (OCN) mRNAs but had no effect on the mRNA expression of osteopontin (OPN), the latter two being noncollagenous proteins related to bone matrix mineralization. These findings suggest that PC-3 CM contains a factor that inhibits osteoblastic cell differentiation and that this factor may be involved in the process of bone metastasis from prostatic carcinoma.