A randomised, double-blind, placebo-controlled crossover trial of the influence of the HCN channel blocker ivabradine in a healthy volunteer pain model: an enriched population trial.

Preclinical studies suggest that type 2 hyperpolarization-activated cyclic nucleotide gated ion channels (HCN2) are necessary for neuropathic pain. This trial assessed the influence of ivabradine, a nonselective HCN channel blocker, on capsaicin-induced hyperalgesia and pain in healthy human subjects. An enriched population comprising subjects who developed >20 cm of punctate hyperalgesia from topical capsaicin (0.5% cream applied onto 9 cm area) was identified. These subjects then received ivabradine (15 mg) or placebo 1 hour before capsaicin application in randomly allocated order in a crossover study. The forearm site for capsaicin alternated with each application of the cream. The interval of time from screening to the first and to the second treatment visits was at least 3 and 5 weeks, respectively, to minimize carryover effects. Fifty-five participants were screened, of which 25 completed at least 1 treatment visit. Intention-to-treat hierarchical analysis revealed no significant effects of the drug on primary trial outcome, defined as a difference in effects of placebo and ivabradine on the area of punctate hyperalgesia (ivabradine - placebo: mean = 3.22 cm, 95% confidence interval: = -4.04 to 10.48, P = 0.37). However, ivabradine caused a slowing of heart rate (difference of 10.10 beats per minute [95% confidence interval -6.48 to -13.73; P-value <0.0001]). We conclude that ivabradine lacks analgesic effects in the capsaicin pain model at a dose that caused appreciable slowing of heart rate and, hence, is unlikely to prove a useful analgesic in humans. More selective drugs are required to establish a role of HCN2 for pain in humans.

Capecitabine and streptozocin ± cisplatin in advanced gastroenteropancreatic neuroendocrine tumours.

BACKGROUND: Cytotoxic chemotherapy is widely used for advanced, unresectable pancreatic and other gastrointestinal foregut neuroendocrine tumours (NETs) and the most commonly used regimen combines 5-fluorouracil with streptozocin. The NET01 trial was designed to investigate whether capecitabine combined with streptozocin was an acceptable regimen with or without adding cisplatin. METHODS: Patients with advanced, unresectable NETs of pancreatic, gastrointestinal foregut or unknown primary site were randomised to receive three-weekly capecitabine (Cap) 625 mg/m(2) twice daily orally, streptozocin (Strep) 1.0 g/m(2) intravenously on day 1, with or without cisplatin (Cis) 70 mg/m(2) intravenously on day 1. The primary outcome measure was objective response. Secondary outcome measures included progression-free and overall survival, quality of life, toxicity and biochemical response. RESULTS: 86 (44 CapStrep, 42 CapStrepCis) patients were randomised. Best objective response rate was 12% (95% confidence interval (CI)=2-22%) with CapStrep and 16% (95% CI=4-27.4%) with CapStrepCis. Disease-control rate was 80% with CapStrep and 74% with CapStrepCis. The estimated median progression-free and overall survival were 10.2 and 26.7 months for CapStrep and 9.7 and 27.5 months for CapStrepCis. 44% of CapStrep and 68% of CapStrepCis patients experienced grade ≥3 adverse events. INTERPRETATION: The efficacies of the novel CapStrep±Cis regimens were very similar. CapStrep was better tolerated than CapStrepCis. The trial was registered as EudraCT: 2004-005202-71 and ISRCTN: 35124268.

The 2nd Annual Irish Drug Delivery Network Conference with UK and Ireland Controlled Release Society: advancing drug delivery.

This meeting was part funded by Science Foundation Ireland and by the University College Dublin Seed-Funding program, and was an opportunity for the Irish Drug Delivery Network to invite selected internationally-recognized scientists from across Europe onto a program, together with some of its own principal investigators. The meeting was co-promoted by the UK and Ireland Controlled Release Society. Topics included fluorescent dyes for stability testing of proteins, engineering of nano-containers, peptide-polymer conjugates, designing novel biomaterials, oral liquid-emulsion drug delivery systems, barrier modulation for drug delivery to the eye using siRNA, cell-specific targeting in the lungs, hot-melt extrusion and modified cyclodextrins for delivery of siRNA. The conference was attended by 85 researchers and the Irish Drug Delivery Network co-chairs were Caitriona O'Driscoll (University College Cork) and David Brayden (University College Dublin).

Nanotubes with the TiO2-B structure.

Here we report the first synthesis of TiO2-B nanotubes by a simple hydrothermal route; lithium may be intercalated up to a composition of Li(0.98)TiO2 compared with Li(0.91)TiO2 for the corresponding nanowires.

Induction of chromatid breaks by carbon K-shell ultrasoft X rays.

Chromatid breaks have previously been shown to be induced in G2-phase cells after exposure to ionizing radiation (X and gamma rays) as a linear function of dose, consistent with a single-event mechanism. DNA double-strand breaks (DSBs) are thought to be the initiating lesion, and experiments with a genetically engineered cell line containing a single DSB site also indicate that a single DSB is sufficient to induce a chromatid break. Although the precise mechanism of conversion of an isolated DSB into a chromatid break is not yet understood, it is known that a proportion of chromatid breaks result from rearrangements between sister chromatids. Here we report further evidence for the single-event hypothesis for the formation of chromatid breaks. The evidence derives from experiments in which chromatid breaks have been induced by exposure of Chinese hamster cells to ultrasoft carbon K-shell X rays. Since the energy of carbon K-shell X rays is not sufficient for the secondary electrons to span more than one DNA double helix, we conclude that single traversals, and hence single (complex) DSBs, are responsible for the formation of chromatid breaks. We find that, as for 60Co gamma rays, around 10% of the carbon K-shell X-ray-induced chromatid breaks have associated color switches at breakpoints, indicating that they arise through sister chromatid rearrangements.