1H-NMR study of the quadruplex [d(TGGGT)]4 containing a modified thymine

A NMR structural study of quadruplex [d(TGGGT)]4 containing a modified thymine is reported. The three dimensional structure of the complex is very similar to those of other parallel stranded quadruplexes. The modified thymines (T*) are able, at least in the minimised structures, to form a tetrad containing extra H-bonds through the hydroxyl groups. Nevertheless, in this new tetrad the modified thymines are slightly open towards the solvent respect to the unmodified T-tetrad.     

Eradication of Helicobacter pylori infection improves blood pressure values in patients affected by hypertension

Background. Arterial hypertension is a risk factor for atherosclerosis of whose pathogenesis is unknown. Growing evidence underscores the causative role of endothelial dysfunction. A possible association between Helicobacter pylori infection and cardiovascular and autoimmune disorders has been found. The release of cytotoxic substances either of bacterial origin or produced by the host may represent mediators of these systemic sequelae. The aim of our study was to determine the prevalence of H. pylori infection in hypertensive patients and the effects of H. pylori eradication on blood pressure and on digestive symptoms. Materials and Methods. Seventy‐two hypertensive patients (34 male and 38 female; mean age 53 ± 12 years) and 70 normotensive controls (35 male and 35 female; mean age 52 ± 10 years) were enrolled. All patients were subjected to a first ambulatory blood pressure monitoring (ABPM) at enrollment, a ¹³C urea breath test and a test for IgG‐CagA antibodies, and completed the validated dyspepsia questionnaire. H. pylori‐positive patients were treated with triple therapy (amoxicillin, clarithromycin and ranitidine bismute citrate) for 7 days. Control of eradication was assessed by ¹³C urea breath test, and all patients underwent a second ABPM 6 months after enrollment. Results. H. pylori infection was 55% in hypertensive patients, with 90% CagA positivity, and 50% in controls, with 60% CagA positivity. At the first ABPM, blood pressure values were similar in H. pylori‐positive and ‐negative individuals; positive patients showed a significant increase in pyrosis and epigastric pain compared to negative patients. H. pylori was eradicated in 80% of patients and in 85% of controls. At the second ABPM, we found a statistically significant decrease in 24‐hour mean blood pressure values when compared to the first ABPM only in the eradicated hypertensive group. Conclusions. Our study demonstrated a significant decrease in blood pressure values, in particular in diastolic blood pressure values, after H. pylori eradication in hypertensive patients. A high prevalence of CagA positivity was found. The association between cardiovascular disease and H. pylori infection seems pronounced only in CagA‐positive patients. The possible links between hypertensive disease and H. pylori infection may involve the activation of the cytokine cascade with the release of vasoactive substances from the primary site of infection, or molecular mimicry between the CagA antigens of H. pylori and some peptides expressed by endothelial cells and smooth muscle cells.     

Gene expression analysis in burn wounds of rats

The events occurring early in the burn wound trigger a sequence of local and systemic responses that influence cell and tissue survival and, consequently, wound healing and recovery. Using high-density oligonucleotide arrays we identified gene expression patterns in skin samples taken from a region of injury in the burn rat model. The associated genomic events include the differential expression of genes involved in cell survival and death, cell growth regulation, cell metabolism, inflammation, and immune response. The functional gene cluster detected and their time appearance matched the time sequence known to occur in burn wound healing.     

Apoptotic changes in the aged brain are triggered by interleukin-1beta-induced activation of p38 and reversed by treatment with eicosapentaenoic acid

Among the several changes that occur in the aged brain is an increase in the concentration of the proinflammatory cytokine interleukin-1beta that is coupled with a deterioration in cell function. This study investigated the possibility that treatment with the polyunsaturated fatty acid eicosapentaenoic acid might prevent interleukin-1beta-induced deterioration in neuronal function. Assessment of four markers of apoptotic cell death, cytochrome c translocation, caspase-3 activation, poly(ADP-ribose) polymerase cleavage, and terminal dUTP nick-end staining, revealed an age-related increase in each of these measures, and the evidence presented indicates that treatment of aged rats with eicosapentaenoate reversed these changes as well as the accompanying increases in interleukin-1beta concentration and p38 activation. The data are consistent with the idea that activation of p38 plays a significant role in inducing the changes described since interleukin-1beta-induced activation of cytochrome c translocation and caspase-3 activation in cortical tissue in vitro were reversed by the p38 inhibitor SB203580. The age-related increases in interleukin-1beta concentration and p38 activation in cortex were mirrored by similar changes in hippocampus. These changes were coupled with an age-related deficit in long term potentiation in perforant path-granule cell synapses, while eicosapentaenoate treatment was associated with reversal of age-related changes in interleukin-1beta and p38 and with restoration of long term potentiation.     

Ecological regulation of development: induction of marine invertebrate metamorphosis

In the marine environment a wide range of invertebrates have a pelagobenthic lifecycle that includes planktonic larval and benthic adult phases. Transition between these morphologically and ecologically distinct phases typically occurs when the developmentally competent larva comes into contact with a species-specific environmental cue. This cue acts as a morphogenetic signal that induces the completion of the postlarval/juvenile/adult developmental program at metamorphosis. The development of competence often occurs hours to days after the larva is morphologically mature. In the non-feeding--lecithotrophic--larvae of the ascidian Herdmania curvata and the gastropod mollusc Haliotis asinina, gene expression patterns in pre-competent and competent stages are markedly different, reflecting the different developmental states of these larval stages. For example, the expression of Hemps, an EGF-like signalling peptide required for the induction of Herdmania metamorphosis, increases in competent larvae. Induction of settlement and metamorphosis results in further changes in developmental gene expression, which apparently is necessary for the complete transformation of the larval body plan into the adult form.     

Sensory neurons of the Atonal lineage pioneer the formation of glomeruli within the adult Drosophila olfactory lobe

The first centers for processing of odor information by animals lie in the olfactory lobe. Sensory neurons from the periphery synapse with interneurons in anatomically recognizable units, termed glomeruli, seen in both insects and vertebrates. The mechanisms that underlie the formation of functional maps of the odor-world in the glomeruli within the olfactory lobe remains unclear. We address the basis of sensory targeting in the fruitfly Drosophila and show that one class of sensory neurons, those of the Atonal lineage, plays a crucial role in glomerular patterning. Atonal-dependent neurons pioneer the segregation of other classes of sensory neurons into distinct glomeruli. Furthermore, correct sensory innervation is necessary for the arborization of projection neurons into glomeruli and for the elaboration of processes of central glial cells into the lobe.     

Antisense MBD2 gene therapy inhibits tumorigenesis

Background

Aberration in the pattern of DNA methylation is one of the hallmarks of cancer. We present data suggesting that dysregulation of MBD2, a recently characterized member of a novel family of methylated DNA binding proteins, is involved in tumorigenesis. Two functions were ascribed to MBD2, DNA demethylase activity and repression of methylated genes.

Methods

Multiple antisense expression and delivery systems, transfection, electrotransfer and adenoviral were employed to demonstrate that MBD2 is essential in tumorigenesis, both ex vivo and in vivo.

Results

Inhibition of MBD2 by antisense expression resulted in inhibition of anchorage‐independent growth of antisense transfected cancer cells or cells infected with an adenoviral vector expressing MBD2 antisense. Xenograft tumors treated with an adenoviral vector expressing MBD2 antisense or xenografts treated with electrotransferred plasmids expressing MBD2 antisense showed reduced growth.

Conclusions

These results support the hypothesis that one or both of the functions described for MBD2 are critical in tumorigenesis and that MBD2 is a potential anticancer target. Copyright © 2002 John Wiley & Sons, Ltd.

     

Parathyroid hormone-related protein enhances PC-3 prostate cancer cell growth via both autocrine/paracrine and intracrine pathways

Parathyroid hormone-related protein (PTHrP) is expressed by human prostatic tissue and prostate cancer cell lines, and positively influences primary prostate tumor growth in vivo. The human prostate cancer cell line PC-3, which expresses functional PTH/PTHrP receptors, was used as a model to study the effects of PTHrP on prostate cancer cell growth. Addition of PTHrP (1-34), (1-86), and (1-139) increased cell number and [3H]thymidine incorporation; these effects were reversed by anti-PTHrP antiserum. This antiserum also decreased endogenous PC-3 cell growth. Clonal PTHrP-overexpressing PC-3 cell lines also showed enhanced cell growth and [3H]thymidine incorporation and were enriched in the G2+M phase of the cell cycle, suggesting an effect of PTHrP on mitosis. Overexpression of PTHrP with the nuclear localization sequence (NLS) deletion partially reversed the growth-stimulatory effects. The growth rate of these cells was midway between that of wild-type PTHrP-overexpressing and control cells, presumably because NLS-mutated PTHrP is still secreted and acts through the cell surface PTH/PTHrP receptor. In contrast to NLS-mutated PTHrP, wild-type protein showed preferential nuclear localization. These results suggest that the proliferative effects of PTHrP in PC-3 cells are mediated via both autocrine/paracrine and intracrine pathways, and that controlling PTHrP production in prostate cancer may be therapeutically beneficial.