Gas chromatography/mass spectrometric analysis of urinary nucleosides in cancer patients; potential of modified nucleosides as tumour markers.

Analysis of urine from cancer patients by capillary gas chromatography/mass spectrometry positively identified 14 urinary nucleosides including several modified nucleosides. Levels of the modified nucleosides 1-methyl-adenosine, 2-methylguanosine, N2,N2-dimethylguanosine and 1-methylinosine as well as the total nucleoside level were elevated in the urine when a malignant tumour was present; the levels of N2,N2-dimethylguanosine were found to correlate with the stage of the cancer.

Inducible removal of UV-induced pyrimidine dimers from transcriptionally active and inactive genes of Saccharomyces cerevisiae.

The prior UV irradiation of alpha haploid Saccharomyces cerevisiae with a UV dose of 25 J/m2 substantially increases the repairability of damage subsequently induced by a UV dose of 70 J/m2 given 1 h after the first irradiation. This enhancement of repair is seen at both the MAT alpha and HML alpha loci, which are, respectively, transcriptionally active and inactive in alpha haploid cells. The presence in the medium of the protein synthesis inhibitor, cycloheximide in the period between the two irradiations eliminated this effect.

Evidence that generation of inositol 1,4,5-trisphosphate and hydrolysis of phosphatidylinositol 4,5-bisphosphate are rapid responses following addition of fungal elicitor which induces phytoalexin synthesis in lucerne (Medicago sativa) suspension culture cells.

Treatment of lucerne suspension culture cells with glycoprotein elicitor from the phytopathogenic fungus Verticillium albo-atrum R & B triggers Ca(2+)-mediated induction of antimicrobial secondary metabolites termed phytoalexins. The present study investigated the possible role of polyphosphoinositide signal transduction in phytoalexin elicitation. Within 1 min of addition of elicitor to lucerne suspension culture cells we found a 100-160% (15-25 pmol/g fresh wt) increase in the level of compound with chromatographic and electrophoretic properties expected for an inositol trisphosphate (InsP3) and which was strongly bound by an inositol 1,4,5-trisphosphate (Ins(1,4,5)P3)-specific binding protein; after 3 min the level of this compound had fallen below that observed prior to elicitor challenge.

Induction of micronuclei in V79 Chinese hamster cells by hydroquinone and econazole nitrate.

Two suspect aneugens (hydroquinone and econazole nitrate) were examined for their ability to induce micronuclei in a number of V79 Chinese hamster cell lines which express rat cytochrome P-450 cDNAs. Hydroquinone elevated micronucleated cell frequencies in a dose-dependent manner in cell lines V79, XEM2 (expresses CYP1A1) and SD1 (expresses CYP2B1). Econazole nitrate was an effective inducer of micronuclei over a narrow dose range in cell lines V79, XEM2 and XEMd-MZ (expresses CYP1A2).

The detection and assessment of the aneugenic potential of environmental chemicals: the European Community Aneuploidy Project.

Within the framework of its' Environment Research and Development Programme, the European Communities (EC) Directorate General (DG) XII has supported a research project aimed at developing and validating assay systems for the detection and evaluation of chemicals capable of inducing numerical chromosome changes such as aneuploidy and polyploidy. A range of test chemicals were selected, which include a core set comprising; colchicine, econazole nitrate, chloral hydrate, hydroquinone, diazepam, thiabendazole, cadmium chloride, thimerosol, pyrimethamine and vinblastine sulphate. These test chemicals were used to evaluate the ability of test systems ranging from tubulin polymerisation, fungal cultures, cultured mammalian cells and intact rodents to detect chemical aneugens and to assess the significance of such activity to exposed human populations.

A comparison of two in vitro mammalian cell cytogenetic assays for the detection of mitotic aneuploidy using 10 known or suspected aneugens.

Two in vitro cytogenetic assays were evaluated for their ability to detect aneugenic and polyploidy-inducing agents using a battery of 10 known or suspected aneugens supplied as part of the EEC 4th Environmental Research and Development Programme. The compounds tested were colchicine, vinblastine, chloral hydrate, thiabendazole, hydroquinone, thimerosal, cadmium chloride, econazole nitrate, pyrimethamine and diazepam. The cell division aberration assay employed a differential chromosome/spindle staining procedure to detect perturbations of the mitotic division apparatus.

An evaluation of the use of in vitro tubulin polymerisation, fungal and wheat assays to detect the activity of potential chemical aneugens.

The test chemicals included in the EC Aneuploidy Project were evaluated for their ability to induce aneuploidy or aneuploidy related endpoints in assays using in vitro tubulin polymerisation, fungi and wheat. The results obtained demonstrated considerable qualitative and quantitative differences between the responses of the assays to the 10 test chemicals. Fungal assays failed to respond to the potent mammalian spindle poisons colchicine and vinblastine and only three chemicals were positive in all three fungal test systems i.

Personalia and the current health crisis.

Recent changes in the Russian government introduced by Boris Yeltsin include the appointment of Eduard Nechaev as health minister at the beginning of this year. The appointment received little publicity in the West, although his predecessor was sacked after only one year for failing to make any effort to improve health care. The challenges facing the new minister are enormous.

Muscimol infused into the entorhinal cortex prior to training blocks the involvement of this area in post-training memory processing.

Muscimol infusions into the entorhinal cortex (ERC) have previously been reported to impair the retention of passive avoidance learning, but only when infusions were delayed until 90min after training. In the present study, three experiments were carried out to examine further the effects of muscimol infusions into the ERC prior to training. In Experiment 1, muscimol infusions prior to training had no effect on retention, confirming earlier findings, but blocked the amnestic effect of a second muscimol infusion 90min post-training.

Detection of DNA adducts in human oral tissue: correlation of adduct levels with tobacco smoking and differential enhancement of adducts using the butanol extraction and nuclease P1 versions of 32P postlabeling.

Samples of clinically normal oral tissue were obtained from patients undergoing surgery for intraoral squamous cell carcinoma. DNA was extracted from samples obtained from 20 tobacco smokers, four exsmokers, and nine nonsmokers and analyzed for the presence of aromatic DNA adducts using two distinct modifications of the 32P postlabeling assay. 32P postlabeling following butanol extraction enhancement revealed a much wider range and substantially higher levels of DNA adducts than obtained following nuclease P1 enrichment.

"Auditory neglect after right frontal lobe and right pulvinar thalamic lesions": comments on Hugdahl, Wester, and Asbjørnsen (1991) and some preliminary findings.

We take issue with the claim recently made in this journal that extinction of left ear input during dichotic, but not monaural, stimulus presentation demonstrates "auditory attentional neglect" (Hugdahl, Wester, & Asbjørnsen, 1991). We also report on a patient suffering from unilateral visual neglect, who shows extinction under dichotic, but not monaural, conditions of stimulus presentation but this is not confined to one ear. Although this patient denies hearing both of two dichotically presented words, he recognizes the extinguished stimulus when given a forced-choice recognition task.

Determination of free bile acids in pharmaceutical preparations by packed column supercritical fluid chromatography.

A method was developed for the baseline separation of common free bile acids by supercritical fluid chromatography. A phenylbonded silica column, with UV detection at 210 nm, and carbon dioxide modified with methanol as the mobile phase were used. The influence of the stationary phase, modifier concentration, temperature, column pressure, and modifier identity on retention was studied.

Purification of the pro-phenol oxidase enzyme from haemocytes of the cockroach Blaberus discoidalis.

Pro-phenol oxidase was purified from the haemocytes of the cockroach Blaberus discoidalis by Blue Sepharose chromatography, hydrophobic-interaction chromatography on a Phenyl-Superose column and, finally, gel filtration on a Superose 6 column. Results suggest that the molecule exists as a polymer of identical 76 kDa monomeric units. The enzyme is a glycoprotein with pI of 5.

32P-postlabelling analysis of human tissues and its potential use for biomonitoring.

Samples of clinically normal oral tissue were obtained from 17 tobacco smokers and 7 non- or ex-smokers undergoing surgery for intra-oral squamous cell carcinoma. Isolated DNA was analysed for the presence of aromatic DNA adducts using the 32P-postlabelling technique with adduct enhancement by either butanol extraction or nuclease P1 enrichment. DNA adduction detected following butanol extraction was more diverse and at a higher level than obtained with the P1 method.

Detection by HPLC-32P-postlabelling of DNA adducts formed after exposure to epoxybutene and diepoxybutane.

We have developed an HPLC-32P-postlabelling procedure to detect DNA adducts formed by epoxybutene and diepoxybutane. The method exploits the interaction of the two epoxides with deoxynucleotides and polydeoxynucleotides to optimize the HPLC enrichment of adducted nucleotides before 32P-postlabelling. Using this approach, a number of guanine adducts were identified after the exposure of dGMP, poly(dG-dC) or calf thymus DNA to epoxybutene and diepoxybutane, and a major adenine adduct was identified in poly(dA-dT) and calf thymus DNA exposed to diepoxybutane.

Biomonitoring of exposure to 1,3-butadiene: detection by high-performance liquid chromatography and 32P-postlabelling of an adenine adduct formed by diepoxybutane.

1,2-Epoxy-3-butene and 1,2:3,4-diepoxybutane, the two oxidative metabolites of 1,3-butadiene, are considered to be involved in some of the carcinogenicity of the parent compound. Diepoxybutane is a bifunctional alkylating agent and reacts with DNA to form monoadducts and cross-links. We investigated DNA alkylation after exposure to diepoxybutane in order to develop a method for human biomonitoring.

Studies of the cell-wall properties of Saccharomyces cerevisiae during fermentation.

The cell-wall properties of three strains of the yeast Sacharomyces cerevisiae have been experimentally studied at various times during fermentation. The cell walls have been characterized by electrophoretic mobility measurements, from which zeta potentials may be calculated. They have also been characterized by computerized pH titration, which gives direct information on the number and nature of groups in the yeast cell wall.

Complementary genes control biparental plastid inheritance in Pelargonium.

Zonal pelargoniums exhibit biparental plastid inheritance. After G x W plastid crosses the progeny are a mixture of green, variegated and white embryos corresponding to a maternal, biparental or paternal inheritance of plastids, respectively. There are two patterns of segregation: type-I females have families in which the majority of embryos are green, variegated are of intermediate frequency and white are the least frequent.

Season of birth and school attendance.

Previous research has shown that summer compared to autumn or spring born children have been found to do less well educationally, to be more likely to have their abilities underestimated and to be considered to have behaviour problems, but not to differ in terms of school attendance. That last result is refuted by the results of this study which is based on more than 5000 pupils in their last year of primary education and which reveals that: (a) after controlling for gender and size of family, the summer born have the poorest and the autumn born the highest attendance rates; and (b) in the case of pupils with attendance rates of 80 per cent or less, more of them are summer born and fewer, autumn born.

Hormonal and neurochemical correlates of various forms of animal "aggression".

The majority of studies attempting to evaluate the roles of hormones and neurochemicals in "aggression" concern laboratory rodents, notably rats and mice, with fewer investigations on infrahuman primates. Studies suggest that situations used to assess aggression (e.g.

Quantitation by fast-atom bombardment mass spectrometry: assay of cytidine 3',5'-cyclic monophosphate-responsive protein kinase.

A protein kinase, stimulated by cytidine 3',5'-cyclic monophosphate, is conventionally assayed by monitoring the incorporation of radiolabelled phosphate from adenosine triphosphate into a histone substrate. Here the assay of the protein kinase is carried out by positive-ion fast-atom bombardment mass spectrometric analysis of the enzyme incubation mixture after the reaction has been terminated. The data so obtained show good agreement with data obtained by the conventional radiometric assay: the intrinsic advantage of the mass spectrometric assay is the capacity for multiple component monitoring; the ability of the kinase to bind competing cyclic nucleotides together with integral adenosine triphosphatase (ATPase) and phosphodiesterase activity can also be assessed.