An evaluation of a smoking prevention programme with children from disadvantaged communities.

This study examined the effect of a novel smoking prevention programme on children in primary schools in disadvantaged areas. The programme included integration with other school subjects as well as parental involvement and visits by Health Board personnel. Compared to matched control groups the classes in which the programme was piloted, showed less positive attitudes towards smoking and greater awareness of the dangerous consequences of smoking.

BCR-ABL maintains resistance of chronic myelogenous leukemia cells to apoptotic cell death.

Apoptosis is the major form of cell death associated with the action of chemotherapeutic agents on tumor cells, and therefore the expression of genes that interfere with apoptosis can have important consequences for the efficacy of therapeutic approaches. Here we show that K562, a chronic myelogenous leukemia (CML) cell line expressing the BCR-ABL fusion protein, are resistant to the induction of apoptosis by a number of agents and conditions. Antisense oligodeoxynucleotides corresponding to the translation start of bcr downregulate bcr-abl protein in these cells and render them susceptible to induction of apoptosis by chemotherapeutic agents or serum deprivation.

Isolation and characterization of a hydrogen peroxide resistant mutant of Bacillus subtilis.

A mutant of Bacillus subtilis has been isolated by continuous selection in increasing concentrations of H2O2. It grew with a doubling time of 85 min in minimal medium containing 150 mM H2O2, whereas the wild-type parent lysed in 100 mM H2O2. The mutant was also more resistant to organic peroxides than the wild-type.

Activation of a calcium magnesium independent endonuclease in human leukemic cell apoptosis.

Cytotoxic drugs induce apoptosis in human tumour cell lines and this is characterised by fragmentation of the cell's DNA into nucleosome size units or multiples thereof. In the present study we demonstrated that nuclei isolated from three human haematopoietic cell lines, HL-60, U937 and K562, contain an endonuclease that is independent of Ca++, Mg++ and Na+ ions for its activity. This contrasts with what has previously been shown for a number of rodent cell types in which apoptosis has been studied.

Phase variation in Xenorhabdus luminescens: cloning and sequencing of the lipase gene and analysis of its expression in primary and secondary phases of the bacterium.

The phenomenon of phase variation in the insect-pathogenic bacterium Xenorhabdus luminescens was investigated. Differential activity of the lipase enzyme (EC 3.1.

Induction of apoptosis in cells of the immune system by cytotoxic stimuli.

Apoptosis is a physiological mode of death where the dying cell plays an active part in its own demise, which contrasts sharply with what is seen in necrosis. In the present paper I have shown that when cells of the immune system are exposed to a range of cytotoxic agents, such as the RNA synthesis inhibitor actinomycin D, the DNA polymerase inhibitor aphidicolin or the topoisomerase I inhibitor campthothecin, they rapidly undergo cell death via apoptosis. This is characterized by DNA fragmentation to yield the now hallmark ladder pattern of death by this mechanism.

Cloning and characterization of genes induced by hydrogen peroxide in Bacillus subtilis.

Transcriptional fusions of Bacillus subtilis DNA to the lacZ gene were screened for induction, initially by ethanol and then by hydrogen peroxide (H2O2). Two fusions were identified which were induced late following treatment with sublethal concentrations of H2O2 (100 microM). The oxy-1 promoter was induced 4-5-fold and mapped to 11 degrees while the oxy-2 promoter was induced 20-fold and mapped close to the right of the defective prophage PBSX, at about 120 degrees.

Elevations in cytosolic free Ca2+ are not required to trigger apoptosis in human leukaemia cells.

Previous studies have indicated that Ca2+ is a trigger for apoptosis (programmed cell death) in thymocytes and related cell lines. Recently we have shown that levels of apoptosis in leukaemic cells are diminished in Ca(2+)-deficient conditions, indicating that Ca2+ may be important in the mechanism of apoptosis in these cells. In the present study we investigated the possibility that Ca2+ serves as a trigger for apoptosis in the human leukaemic cell line, HL-60.

Influence of ploidy on plastome mutagenesis in Nicotiana.

A clear influence of ploidy was observed on the frequency of both spontaneous and nitroso-methylurea (NMU) induced, streptomycin-resistant, adventitious shoots developing on leaf explants of Nicotiana tabacum and N. plumbaginifolia. At nearly all NMU levels employed a significantly higher yield of resistant shoots was obtained from haploid compared with diploid leaf strips.

Regulation of the oxidative stress response by the hpr gene in Bacillus subtilis.

Bacillus subtilis mutants with null mutations in the spo0 A gene are resistant to oxidative stress during the exponential phase of growth. This resistance phenotype can be suppressed by mutations in the abrB gene, or in the hpr gene. Both of these gene products are negative regulatory proteins which are over-produced in a spo0 A strain, and the over-production of the hpr gene product results from over-production of the abrB gene product.

Ultraviolet B irradiation of human leukaemia HL-60 cells in vitro induces apoptosis.

UV radiation is known to be a potent agent for the induction of programmed cell death (apoptosis) in human skin. However, the mechanistic aspects of UV-induced apoptosis remain ill-defined. In this study the effects of varying periods of UV-irradiation on the human leukaemia HL-60 cell line and on five other human cell lines were investigated.

Dose-dependent induction of apoptosis in human tumour cell lines by widely diverging stimuli.

Cell death may occur by either of two mechanisms: apoptosis or necrosis. Necrosis, the first type of cell death to be recognized, is an uncontrolled degenerative phenomenon invariably caused by noxious stimuli and is the result of irreversible failure of membrane function. Apoptosis, on the other hand, is a death process which involves a series of well-organized events which require active cell participation, and is primarily caused by physiological stimuli.

Programmed cell death (apoptosis) in lymphoid and myeloid cell lines during zinc deficiency.

Three human cell lines of lymphoid (Molt-3 and Raji) or myeloid (HL-60) origin were maintained in vitro under zinc-sufficient or zinc-deficient conditions. Under these conditions, cell proliferation, viability and mode of death (apoptotic or necrotic) were assessed. All three cell types decreased their proliferative capacity and viability under conditions of zinc deficiency.

The effect of acclimation temperature on enzyme activity in Drosophila melanogaster.

1. The response to thermal acclimation of five key rate-limiting enzymes of intermediary metabolism and of six degradative enzymes was measured in tissue extracts of adult Drosophila melanogaster which had been acclimated for 4 days to 15, 25 or 30 degrees C. 2.

Enzyme induction in recovering dauer larvae of the nematode Caenorhabditis elegans in response to increasing concentrations of food source in the recovery medium.

Exposure of recovering dauer larvae of Caenorhabditis elegans to increasing concentrations of Escherichia coli in the recovery medium produced dramatic increases in the enzymes of intermediary metabolism. There was no significant difference between the rates of development of recovering dauer larvae grown on different concentrations of E. coli.