Antiproton induced DNA damage: proton like in flight, carbon-ion like near rest

Biological validation of new radiotherapy modalities is essential to understand their therapeutic potential. Antiprotons have been proposed for cancer therapy due to enhanced dose deposition provided by antiproton-nucleon annihilation. We assessed cellular DNA damage and relative biological effectiveness (RBE) of a clinically relevant antiproton beam. Despite a modest LET (,19 keV/mm), antiproton spread out Bragg peak (SOBP) irradiation caused significant residual c-H2AX foci compared to X-ray, proton and antiproton plateau irradiation. RBE of ,1.48 in the SOBP and ,1 in the plateau were measured and used for a qualitative effective dose curve comparison with proton and carbon-ions. Foci in the antiproton SOBP were larger and more structured compared to X-rays, protons and carbon-ions. This is likely due to overlapping particle tracks near the annihilation vertex, creating spatially correlated DNA lesions. No biological effects were observed at 28–42 mm away from the primary beam suggesting minimal risk from long-range secondary particles.

Discovery of a Potent Boronic Acid Derived Inhibitor of the HCV RNA-Dependent RNA Polymerase

A boronic acid moiety was found to be a critical pharmacophore for enhanced in vitro potency against wild type hepatitis C replicons and known clinical polymorphic and resistant HCV mutant replicons. The synthesis, optimization, and structure-activity relationships associated with inhibition of HCV replication in a sub-genomic replication system for a series of non-nucleoside boron-containing HCV RNA-Dependent RNA Polymerase (NS5B) inhibitors are described. A summary of the discovery of GSK5852 (3), a molecule which entered clinical trials in subjects infected with HCV in 2011, is included.

Oxidised, glycated LDL selectively influences tissue inhibitor of metalloproteinase-3 gene expression and protein production in human retinal capillary pericytes

Aims/hypothesis: Matrix metalloproteinases (MMPs) and their natural inhibitors, tissue inhibitor of metalloproteinases (TIMPs), regulate important biological processes including the homeostasis of the extracellular matrix, proteolysis of cell surface proteins, proteinase zymogen activation, angiogenesis and inflammation. Studies have shown that their balance is altered in retinal microvascular tissues in diabetes. Since LDLs modified by oxidation/glycation are implicated in the pathogenesis of diabetic vascular complications, we examined the effects of modified LDL on the gene expression and protein production of MMPs and TIMPs in retinal pericytes. Methods: Quiescent human retinal pericytes were exposed to native LDL (N-LDL), glycated LDL (G-LDL) and heavily oxidised and glycated LDL (HOG-LDL) for 24 h. We studied the expression of the genes encoding MMPs and TIMPs mRNAs by analysis of microarray data and quantitative PCR, and protein levels by immunoblotting and ELISA. Results: Microarray analysis showed that MMP1, MMP2, MMP11, MMP14 and MMP25 and TIMP1, TIMP2, TIMP3 and TIMP4 were expressed in pericytes. Of these, only TIMP3 mRNA showed altered regulation, being expressed at significantly lower levels in response to HOG- vs N-LDL. Quantitative PCR and immunoblotting of cell/matrix proteins confirmed the reduction in TIMP3 mRNA and protein in response to HOG-LDL. In contrast to cellular TIMP3 protein, analysis of secreted TIMP1, TIMP2, MMP1 and collagenase activity indicated no changes in their production in response to modified LDL. Combined treatment with N- and HOG-LDL restored TIMP3 mRNA expression to a level comparable with that after N-LDL alone. Conclusions/interpretation: Among the genes encoding for MMPs and TIMPs expressed in retinal pericytes, TIMP3 is uniquely regulated by HOG-LDL. Reduced TIMP3 expression might contribute to microvascular abnormalities in diabetic retinopathy. © 2007 Springer-Verlag.

Glycation does not alter LDL-induced secretion of tissue plasminogen activator and plasminogen activator inhibitor-1 from human aortic endothelial cells

Diabetes may induce both quantitative and qualitative changes in lipoproteins, especially low-density lipoprotein (LDL). Effects of LDL glycation on endothelial cell secretion of tissue plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) have not been fully elucidated. Human aortic endothelial cell (HAEC) tPA and PAI-1 production were determined after incubation with LDL (50 to 500 microg/mL protein, 24 h) from three sources: (1) nondiabetic LDL (N-LDL) modified in vitro to form six preparations: native, nonmodified (N); glycated (G); minimally oxidized (MO); minimally oxidized and glycated (MOG); heavily oxidized (HO); and heavily oxidized and glycated (HOG); (2) in vivo glycated and relatively nonglycated LDL subfractions from type 1 diabetic patients; (3) LDL from type 1 diabetic patients and matched controls, which was subfractionated using density gradient ultracentrifugation. In experiments using LDL modified in vitro, the rate of tPA release by HAECs incubated with N-LDL (83 +/- 4 ng/mg cell protein/24 h) did not differ significantly from those incubated with G-LDL (73 +/- 7), MO-LDL (74 +/- 13), or MOG-LDL (66 +/- 15) and was not influenced by LDL concentration. The rate of PAI-1 release was similar in HAECs incubated with N-LDL (5.7 +/- 0.6 mug/mg cell protein/24 h), G-LDL (5.7 +/- 0.7), MO-LDL (5.5 +/- 0.8), or MOG-LDL (5.7 +/- 0.9) and was not influenced by LDL concentration. In contrast, tPA release was significantly decreased in cells incubated with LDL (10 microg/mL) modified extensively by oxidation, and averaged 45.2 +/- 5.0 and 43.7 +/- 9.9 ng/mg/24 h for HO-LDL and HOG-LDL, respectively, and was further decreased with increasing concentrations of the heavily oxidized LDL preparations. PAI-1 release was not significantly decreased relative to N-LDL in cells incubated with low concentrations (5 to 50 microg/mL) of HO-LDL and HOG-LDL, but was decreased to 3.2 +/- 0.5 and 3.1 +/- 0.7 microg/mg/24 h for HO-LDL and HOG-LDL at 200 microg/mL, respectively. Results using in vivo glycated versus nonglycated LDL showed that tPA and PAI-1 release did not differ between subfractions. Release of tPA averaged 5.11 +/- 0.6 and 5.12 +/- 0.7 ng/mg/24 h, whereas release of PAI-1 averaged 666 +/- 27 ng/mg/24 h and 705 +/- 30 ng/mg/24 h for nonglycated and glycated LDL subfractions, respectively. Using LDL of different density subclasses, tPA and PAI-1 release in response to LDL from diabetic patients compared with control subjects did not differ when HAECs were incubated with LDLs of increasing density isolated from each subject pair. We conclude that oxidation of LDL, but not glycation, may contribute to the altered fibrinolysis observed in diabetes.

Platelet plasminogen activator inhibitor 1 in patients with type II diabetes

To compare platelet plasminogen activator inhibitor 1 (PAI-1) concentration in type II diabetic patients and healthy control subjects.

Investigations of DNA damage induction and repair resulting from cellular exposure to high dose-rate pulsed proton beams

Studies regarding the radiobiological effects of low dose radiation, microbeam irradiation services have been developed in the world and today laser acceleration of protons and heavy ions may be used in radiation therapy. The application of different facilities is essential for studying bystander effects and relating signalling phenomena in different cells or tissues. In particular the use of ion beams results advantageous in cancer radiotherapy compared to more commonly used X-rays, since the ability of ions in delivering lethal amount of doses into the target tumour avoiding or limiting damage to the contiguous healthy tissues. At the INFN-LNS in Catania, a multidisciplinary radiobiology group is strategically structured aimed to develop radiobiological research, finalised to therapeutic applications, compatible with the use of high dose laser-driven ion beams. The characteristic non-continuous dose rates with several orders of magnitude of laser-driven ion beams makes this facility very interesting in the cellular systems' response to ultra-high dose rates with non-conventional pulse time intervals cellular studies. Our group have projected to examine the effect of high dose laser-driven ion beams on two cellular types: foetal fibroblasts (normal control cells) and DU145 (prostate cancer cells), studying the modulation of some different bio-molecular parameters, in particular cell proliferation and viability, DNA damage, redox cellular status, morphological alterations of both the cytoskeleton components and some cell organelles and the possible presence of apoptotic or necrotic cell death. Our group performed preliminary experiments with high energy (60 MeV), dose rate of 10 Gy/min, doses of 1, 2, 3 Gy and LET 1 keV/µm on human foetal fibroblasts (control cells). We observed that cell viability was not influenced by the characteristics of the beam, the irradiation conditions or the analysis time. Conversely, DNA damage was present at time 0, immediately following irradiation in a dose-dependent manner. The analysis of repair capability showed that the cells irradiated with 1 and 2 Gy almost completely recovered from the damage, but not, however, 3 Gy treated cells in which DNA damage was not recovered. In addition, the results indicate the importance of the use of an appropriate control in radiobiological in vitro analysis.

Effect of the P-glycoprotein inhibitor, R(+)-verapamil on the drug susceptibility of a triclabendazole-resistant isolate of Fasciola hepatica

A study has been carried out to investigate whether the action of triclabendazole (TCBZ) against Fasciola hepatica is altered by the inhibition of P-glycoprotein (Pgp)-linked drug efflux pumps. The Sligo TCBZ-resistant and Cullompton TCBZ-susceptible fluke isolates were used for these experiments and the Pgp inhibitor selected was R(+)-verapamil [R-VPL]. In the first experiment, flukes were initially incubated for 2 h in R-VPL (100 µM), then incubated for a further 22 h in R-VPL+triclabendazole sulphoxide (TCBZ.SO) (50 µg/ml, or 0.1327 µM). For controls, flukes were incubated for 24 h in R-VPL and TCBZ.SO on their own. In a second experiment, flukes were removed from the incubation media following cessation of movement. In the third experiment, Sligo flukes were incubated in lower concentrations of R-VPL (10 µM) and TCBZ.SO (15 µg/ml, or 0.0398 µM). Morphological changes resulting from drug treatment and following Pgp inhibition were assessed by means of scanning electron microscopy. Incubation in R-VPL alone had minimal effect on either isolate. After treatment with TCBZ.SO alone, there was greater surface disruption to the Cullompton than Sligo isolate. However, combined treatment of R-VPL+TCBZ.SO led to more severe surface changes to the Sligo isolate than with TCBZ.SO on its own; this potentiation of drug activity was not seen with the Cullompton isolate. The phenomenon was evident at both concentrations of TCBZ.SO. Inclusion of R-VPL in the incubation medium also reduced the time taken for the flukes to become inactive; again, this effect was more distinct with the Sligo isolate. The results of this study support the concept of altered drug efflux in TCBZ-resistant flukes and indicate that drug transporters may play a role in the development of drug resistance.

Impact of Heat Pump Load on Distribution Networks

Heat pumps can provide domestic heating at a cost that is competitive with oil heating in particular. If the electricity supply contains a significant amount of renewable generation, a move from fossil fuel heating to heat pumps can reduce greenhouse gas emissions. The inherent thermal storage of heat pump installations can also provide the electricity supplier with valuable flexibility. The increase in heat pump installations in the UK and Europe in the last few years poses a challenge for low-voltage networks, due to the use of induction motors to drive the pump compressors. The induction motor load tends to depress voltage, especially on starting. The paper includes experimental results, dynamic load modelling, comparison of experimental results and simulation results for various levels of heat pump deployment. The simulations are based on a generic test network designed to capture the main characteristics of UK distribution system practice. The simulations employ DIgSlILENT to facilitate dynamic simulations that focus on starting current, voltage variations, active power, reactive power and switching transients.

Pharmacokinetics of a CCR5 inhibitor in rhesus macaques following vaginal, rectal and oral application

Objectives: This study measured and compared the pharmacokinetics of CMPD167, a small molecule antiretro- viral CCR5 inhibitor with potential as an HIV microbicide, following vaginal, rectal and oral administration in rhe- sus macaques.
Methods: A vaginal hydroxyethylcellulose (HEC) gel, a rectal HEC gel, a silicone elastomer matrix-type vaginal ring and an oral solution, each containing CMPD167, were prepared and administered to rhesus macaques pretreated with Depo-Provera. CMPD167 concentrations in vaginal fluid, vaginal tissue (ring only), rectal fluid and blood plasma were quantified by HPLC–mass spectrometry.
Results: CMPD167 concentrations measured in rectal fluid, vaginal fluid and blood plasma were highly depend- ent on both the route of administration and the formulation type. Although rectal and vaginal fluid concentra- tions were highest when CMPD167 was administered locally (via either gel or ring), lower concentrations of the drug were also measured in these compartments following administration at the remote mucosal site or orally. CMPD167 levels in the vaginal and rectal fluid following oral administration were relatively low compared with local administration.
Conclusions: The study provides clear evidence for vaginal – rectal and rectal – vaginal drug transfer pathways and suggests that oral pre-exposure prophylaxis with CMPD167 may be less efficacious at preventing sexual trans- mission of HIV-1 than topically applied products.

Longitudinal proton probing of ultrafast and high-contrast laser-solid interactions

We have performed an experiment aimed at measuring self-generated magnetic fields produced in solids by high electron currents following high-intensity and high contrast short-pulse laser irradiation. This was done using longitudinal high resolution proton deflectometry. The experiment was performed at the Titan-JLF laser facility with a high-power short-pulse beam (700 fs, ~ 110 J) split into two beams irradiating two solid targets. One beam is used for the generation of protons and the other beam for the generation of the ultra-high currents of electrons and of the associated magnetic fields. This capability allows us to study the spatio-temporal evolution of the magnetic fields and its dependence on the laser intensity and target material. © Owned by the authors, published by EDP Sciences, 2013.

Novel GlyT1 inhibitor chemotypes by scaffold hopping. Part 2: Development of a [3.3.0]-based series and other piperidine bioisosteres

This Letter describes the development and SAR of a novel series of GlyT1 inhibitors derived from a scaffold hopping approach, in lieu of an HTS campaign, which provided intellectual property position. Members within this new [3.3.0]​-​based series, e.g. I, displayed excellent GlyT1 potency, selectivity, free fraction, and modest CNS penetration. Moreover, enantioselective GlyT1 inhibition was obsd., within this novel series and a no. of other piperidine bioisosteric cores.

Novel GlyT1 inhibitor chemotypes by scaffold hopping. Part 1: Development of a potent and CNS penetrant [3.1.0]-based lead

This Letter describes the development and SAR of a novel series of GlyT1 inhibitors derived from a scaffold hopping approach that provided a robust intellectual property position, in lieu of a traditional, expensive HTS campaign. Members within this new [3.1.0]​-​based series displayed excellent GlyT1 potency, selectivity, free fraction, CNS penetration and efficacy in a preclin. model of schizophrenia (prepulse inhibition)​.