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Aims. A pilot project has been carried out to measure circumstellar CO emission from three OH/IR stars close to the Galactic centre. The intention was to find out whether it would be possible to conduct a large-scale survey for mass-loss rates using, for example, the Atacama large millimeter array (ALMA). Such a survey would increase our understanding of the evolution of the Galactic bulge.

Context. Water fountain stars are very young post-AGB stars with high velocity water maser jets. They are the best objects in which to study the onset of bipolar jets from evolved stars due to their young dynamical ages. However, none of them has been observed in any thermal lines.

Aims.We have investigated the properties of the central star and dust in the bipolar nebula IRAS 19312+1950, which is an unusual object showing the characteristics of a supergiant, a young stellar object, and an asymptotic giant branch (AGB) star.

A SiO maser survey in the $J=1{-}0$, $v=1$and 2 transitions has been made for IRAS sources in the North Galactic Cap (b> 30°) with the Nobeyama 45 m radio telescope. The sources were selected on the basis of their IRAS 12/25-${\mu}$m and 25/60-${\mu}$m flux ratios as likely oxygen-rich AGB candidates. SiO masers were detected from 24 out of the 97 selected sources, where 17 were new detections. The distances and heights above the Galactic plane are calculated. The Galactic distribution of detected and undetected stars indicates that metallicity is likely to govern the detection rate. The Galactocentric angular velocities of the subsampled stars are derived and their variation with the Galactic height is discussed.

Controlled cationic polymerization of p-(chloromethyl)styrene (CMS) was achieved with an alcohol [CH3CH(Ph)OH] as an initiator and a highly oxophilic Lewis acid, BF3·OEt2, as an activator/catalyst. The polymerization is initiated by the BF3-mediated selective activation of the C−O bond of the alcohol and proceeds via a similar activation of the resulting ~~C−OH dormant polymer terminal to give linear polymers without branched structures that would form via reactions of the chloromethyl pendent groups. Addition of a small amount of water retarded the polymerization to give controlled molecular weights that increased with conversion and were close to the calculated values for living polymers. Additional use of tetrabutylammonium hydroxide (n-Bu4NOH) as a hydroxide anion source further narrowed the molecular weight distribution (Mw/Mn = 1.5−1.8). Copolymerization of CMS and styrene or p-chlorostyrene with the BF3-based system also gave copolymers with controlled molecular weights. This is the first example of controlled cationic polymerization of CMS without concurrent side reactions of the chloromethyl functional groups. The success owes to the use of highly oxophilic BF3·OEt2 in conjunction with an appropriate alcoholic initiator.

A controlled cationic polymerization of styrene was achieved with an alcohol [water−vinyl monomer adduct:  CH3CR(Ph)OH; −R = −H (2), −CH3 (3)] as an initiator coupled with BF3OEt2. In the presence of a fairly large amount of water, the polymerization gave polymers with molecular weights that increased in direct proportion to monomer conversion and agreed well with the calculated values, assuming that one initiator molecule generates one polymer chain, although the molecular weight distributions (MWDs) were broad (Mw/Mn ~ 2). 2,6-Di-tert-butyl-4-methylpyridine (DTBMP) and tetrabutylammounium hydroxide (n-Bu4NOH) retarded the polymerization and narrowed the MWDs. ¹H NMR and MALDI−TOF−MS analysis supported the polymerization mechanism where BF3OEt2 selectively and reversibly activates the terminal C−OH bond derived from the initiator to generate the growing cationic species. Similar controlled polymerizations of p-chlorostyrene (pClSt) and p-methylstyrene (pMS) were also achieved by the R−OH/BF3OEt2 system with a proper ratio of water and DTBMP. This is the first example of a controlled cationic polymerization of styrene via reversible activation of the C−OH bond mediated by BF3OEt2 in the presence of water.

Erythropoietin (Ep) levels in spent culture media of a Hep G2 human hepatoblastoma cell line were measured by radioimmunoassay (RIA), fetal mouse liver erythroid colony formation (FMLC), and the exhypoxic polycythemic mouse assay (EHPCMA). The Hep G2 cells at high density produced approximately 700 mU/ml Ep when measured with the RIA. On the other hand, the Ep levels when assayed in EHPCMA and FMLC were 50 and 2,600 mU/ml, respectively. The bioactivity in FMLC was completely neutralized by an antibody to purified human recombinant Ep, indicating that the erythropoietic activity in the Hep G2 spent culture medium was immunologically equivalent to Ep. Ep levels in the medium from low-density Hep G2 cells in 5% O2 and 1% O2 were 2.5- and 4-fold greater, respectively, than that of 20% O2. In contrast, hyperoxia (40% O2) significantly inhibited Ep production. A significant increase in Ep secretion was also observed when the cells were incubated with cobaltous chloride (2 X 10(-6) -2.5 X 10(-4) M). Tunicamycin (0.5 micrograms/ml), which inhibits N-linked glycosylation, significantly reduced the enhancement of Ep secretion induced by hypoxia (1% O2) without affecting cell growth. Forskolin and cholera toxin, each of which increased the levels of cyclic AMP in the Hep G2 cells by 40-fold, produced a significant (P less than 0.05) further increase in Ep secretion in the presence of hypoxia.(ABSTRACT TRUNCATED AT 250 WORDS)

Bladder cancer cells have been shown to secrete a variety of factors that are not related to cells of urothelial origin. The histogenesis of these tumour developments is uncertain, and a variety of theories have been previously reported. In the present manuscript, we identify the factors constitutively produced by a human bladder cancer cell line (KU-19-19) that was found to produce beta human chorionic gonadotrophin (beta-hCG), granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin 1alpha (IL-1alpha), interleukin 6 (IL-6) and interleukin 8 (IL-8). The cells were obtained from a case of metastatic carcinoma that was originally diagnosed to be a grade 3 (WHO classification), invasive transitional cell carcinoma of the bladder. On microscopic observation, the cultured cells exhibited an epithelial appearance with vacuole formation in their cytoplasm. Ultrastructural observations revealed relatively marked microvilli and a tight junction. Significant amounts of beta-hCG, G-CSF, GM-CSF, IL-1alpha, IL-6 and IL-8 concentrations in the supernatant from cultured cells were demonstrated by enzyme-linked immunosorbent assays, while the expression of mRNA of these marker proteins in cancer cells was also significantly exhibited by reverse transcription polymerase chain reaction (RT-PCR). In addition, the expression of G-CSF receptor and IL-6 receptor mRNA was also shown by RT-PCR. Xenograft transplantability using nude mice was observed in association with the presence of severe neutrophilia in the peripheral blood. These results indicate that this cell line appears to be an effective model for the study of transitional cell carcinoma of the bladder with multipotent differentiation potentials.

This study was undertaken to investigate the intracellular induction of reactive oxygen species (ROS) by cis-dichlorodiammineplatinum (CDDP) and the augmentation of their cytotoxicity in bladder cancer cells (KU7) by enhancement of ROS generation by the glutathione (GSH) depletors buthionine sulphoximine (BSO) and diethylmaleate (DEM). CDDP-induced cytotoxicity in KU7 cells and its modulation by GSH depletors were determined using spectrophotometric measurement with crystal violet staining. The effects of GSH depletors on intracellular GSH levels were confirmed using the GSH reductase-DTNB recycling method. Intracellular ROS generation induced by CDDP with or without GSH depletors was estimated from the amount of intracellular dichlorofluorescein (DCF), an oxidized product of dichlorofluorescein (DCFH), which was measured with an anchored cell analysis and sorting system. The cytotoxic effects of CDDP (IC50 15.0 +/- 2.5 microM) were significantly enhanced by BSO (IC50 9.3 +/- 2.6 microM, P < 0.01) and DEM (IC50 10.3 +/- 0.3 microM, P <0.01). BSO and DEM produced a significant depletion in intracellular GSH levels (9.6 +/- 0.4 nmol 10(-6) cells, 17.9 +/- 1.0 nmol 10(-6) cells) compared with the controls (30.5 +/- 0.6 nmol 10(-6) cells). Intracellular DCF production in KU7 cells treated with CDDP (1.35 +/- 0.33 microM) was significantly enhanced by the addition of BSO (4.43 +/- 0.33 microM) or DEM (3.12 +/- 0.22 microM) at 150 min. These results suggest that ROS may play a substantial role in CDDP-induced cytotoxicity and that GSH depletors augment its cytotoxicity through an enhancement of ROS generation in bladder cancer cells.

The present studies were undertaken to assess the effects of atrial natriuretic factor (ANF) on erythropoietin (Ep) secretion in Ep-producing renal carcinoma (RC) cells using a sensitive radioimmunoassay for Ep. Human ANF produced a significant dose-related increase in Ep secretion at concentrations of 10(-7) and 10(-6) M when compared with vehicle controls. ANF (greater than or equal to 10(-9) M) also significantly increased the intracellular guanosine 3',5'-cyclic monophosphate (cGMP) concentration after 5-min incubation with the RC cells. Scatchard analysis of the human 125I-labeled ANF binding data indicated that the RC cells contain a single class of binding sites with a dissociation constant (Kd) of 93 +/- 1 pM and a binding capacity of 2,190 +/- 750 sites/cell. Incubation of the RC cells with 8-bromo-cGMP in concentrations of 10(-7)-10(-5) M also produced a significant dose-related enhancement of Ep secretion. These findings suggest that the increase in Ep secretion in response to ANF can be attributed, at least in part, to activation of guanylate cyclase, which is coupled to specific ANF receptors on the RC cell.

The present studies were undertaken to assess the direct effects of N6-cyclohexyladenosine (CHA), a stable adenosine analogue, on erythropoietin (Ep) secretion in hepatocellular carcinoma cells (Hep 3B). Ep levels in the medium of low density Hep 3B cells treated with CHA in concentrations of 10(-5) and 5 x 10(-5) M for 20 h under hypoxic conditions (1% O2) were significantly higher than that of hypoxic controls. In addition, CHA at the same concentrations produced significant increases in adenosine 3',5'-cyclic monophosphate (cAMP) levels in Hep 3B cells after 1-h incubation under hypoxic conditions when compared with hypoxic controls. Dibutyryl cAMP (10(-5), 10(-4) M) also caused significant increases in Ep secretion when compared with control hypoxic cells. On the other hand, 8-phenyltheophylline, an adenosine receptor antagonist, significantly inhibited the stimulatory effects of CHA on both Ep secretion and cAMP accumulation in the Hep 3B cell cultures in response to hypoxia. These data suggest that Ep secretion may be regulated by adenosine receptor-coupled activation of adenylyl cyclase and the generation of cAMP.