Regulation of a rat VL30 element in human breast cancer cells in hypoxia and anoxia: role of HIF-1

Novel approaches to cancer gene therapy currently exploit tumour hypoxia to achieve transcriptional targeting using oxygen-regulated enhancer elements called hypoxia response elements. The activity of such elements in hypoxic cells is directly dependent on upregulation of the hypoxia-inducible transcription factor-1 However tumours also contain areas of anoxia, which may be considered a more tumour-selective transcriptional stimulus than hypoxia for targeting gene therapy to tumours. Another element, from the rat virus-like retrotransposon, VL30 (termed the ‘secondary anoxia response element’) has been reported to be more highly inducible in rat fibroblasts under anoxia than hypoxia. To investigate anoxia as a potential transcriptional target in human tumours, we have examined secondary anoxia response element inducibility in two human breast cancer cell lines, MCF-7 and T47D, under anoxia, hypoxia and normoxia. In both cell types, the trimerised secondary anoxia response element showed greater inducibility in anoxia than hypoxia (1% and 0.5% O2). The anoxic response of the secondary anoxia response element was shown to be dependent on hypoxia-inducible transcription factor-1 and the presence of a hypoxia-inducible transcription binding site consensus (5′-ACGTG-3′). Mutational analysis demonstrated that the base immediately 5′ to this modulates the anoxic/hypoxic induction of the secondary anoxia response element, such that TACGTG>GACGTG>>CACGTG. A similar correlation was found for erythropoietin, phosphoglycerate kinase 1, and aldolase hypoxia response elements, which contain these respective 5′ flanking bases

Identification of Radiopure Titanium for the LZ Dark Matter Experiment and Future Rare Event Searches

The LUX-ZEPLIN (LZ) experiment will search for dark matter particle interactions with a detector containing a total of 10 tonnes of liquid xenon within a double-vessel cryostat. The large mass and proximity of the cryostat to the active detector volume demand the use of material with extremely low intrinsic radioactivity. We report on the radioassay campaign conducted to identify suitable metals, the determination of factors limiting radiopure production, and the selection of titanium for construction of the LZ cryostat and other detector components. This titanium has been measured with activities of $^{238}$U$_{e}$~$<$1.6~mBq/kg, $^{238}$U$_{l}$~$<$0.09~mBq/kg, $^{232}$Th$_{e}$~$=0.28\pm 0.03$~mBq/kg, $^{232}$Th$_{l}$~$=0.25\pm 0.02$~mBq/kg, $^{40}$K~$<$0.54~mBq/kg, and $^{60}$Co~$<$0.02~mBq/kg (68\% CL). Such low intrinsic activities, which are some of the lowest ever reported for titanium, enable its use for future dark matter and other rare event searches. Monte Carlo simulations have been performed to assess the expected background contribution from the LZ cryostat with this radioactivity. In 1,000 days of WIMP search exposure of a 5.6-tonne fiducial mass, the cryostat will contribute only a mean background of $0.160\pm0.001$(stat)$\pm0.030$(sys) counts.Comment: 13 pages, 3 figures, accepted for publication in Astroparticle Physic

Simulations of events for the LUX-ZEPLIN (LZ) dark matter experiment

The LUX-ZEPLIN dark matter search aims to achieve a sensitivity to the WIMP-nucleon spin-independent cross-section down to (1–2)×10−12 pb at a WIMP mass of 40 GeV/c2. This paper describes the simulations framework that, along with radioactivity measurements, was used to support this projection, and also to provide mock data for validating reconstruction and analysis software. Of particular note are the event generators, which allow us to model the background radiation, and the detector response physics used in the production of raw signals, which can be converted into digitized waveforms similar to data from the operational detector. Inclusion of the detector response allows us to process simulated data using the same analysis routines as developed to process the experimental data

Projected WIMP sensitivity of the LUX-ZEPLIN dark matter experiment

LUX-ZEPLIN (LZ) is a next-generation dark matter direct detection experiment that will operate 4850 feet underground at the Sanford Underground Research Facility (SURF) in Lead, South Dakota, USA. Using a two-phase xenon detector with an active mass of 7 tonnes, LZ will search primarily for low-energy interactions with weakly interacting massive particles (WIMPs), which are hypothesized to make up the dark matter in our galactic halo. In this paper, the projected WIMP sensitivity of LZ is presented based on the latest background estimates and simulations of the detector. For a 1000 live day run using a 5.6-tonne fiducial mass, LZ is projected to exclude at 90% confidence level spin-independent WIMP-nucleon cross sections above 1.4×10-48 cm2 for a 40 GeV/c2 mass WIMP. Additionally, a 5σ discovery potential is projected, reaching cross sections below the exclusion limits of recent experiments. For spin-dependent WIMP-neutron(-proton) scattering, a sensitivity of 2.3×10-43 cm2 (7.1×10-42 cm2) for a 40 GeV/c2 mass WIMP is expected. With underground installation well underway, LZ is on track for commissioning at SURF in 2020

Behavioural observations in gunn rats

The Gunn rat is a hooded mutant of albino rat with various biochemical defects, including a low UDP-glucuronosyl-transferase activity. As a consequence, about half of their offspring are jaundiced from birth, due to high free bilirubin levels, and develop widespread brain damage. The behaviour of both jaundiced and nonjaundiced Gunn rats was studied in four different tests in a shuttle-box and in a stepthrough passive avoidance situation, and compared with that of normal hooded rats. No differences among groups were found in performance of shuttle responses to a tone in a pseudoconditioning paradigm in which tones and shocks were given at random. However, rats from the two Gunn groups made less shuttlings to the tone in two tests that involved an avoidance contingency (each response cancelled one shock). In addition, nonicteric Gunn rats also performed poorly in a classical conditioning test in the shuttle-box (tones and shocks paired on every trial regardless of responses). This last deficiency of non-icteric Gunn rats may be explained by their higher tendency to freeze in situations involving stimulus-stimulus interactions. They also showed a higher latency than that of the two other groups to enter the dark side of the step-through apparatus on their first exposure to it. All animals seemed to learn the passive-avoidance task to the same extent, however, as shown in a retest carried out 48 h later. Both Gunn groups were hypersensitive to the stereotyped-behaviour-inducing action of apomorphine (0.125–1.0 mg/kg, i.p.), but all groups were about equally sensitive to that of d -amphetamine sulfate (0.5–4.0 mg/kg). Since apomorphine is disposed of by glucuronidation, this might be explained by the low UDP-glucuronosyl-transferase activity known to exist in the Gunn animals. The present results show that additional genetic defects have developed by in-breeding in the Gunn population, which are unrelated to brain damage caused by bilirubin, and which can be well characterized from a behavioural standpoint.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46403/1/213_2004_Article_BF00426881.pd

Processing of leather using deep eutectic solvents

Processing of leather has an historical reputation as a chemically and energetically intensive process that produces large volumes of aqueous waste. Saline pollution combined with heavy-metal, dyes and acid and base streams make leather production an ecologically sensitive industry. The current study shows that a variety of deep eutectic solvents (DESs) may be used for the tanning, fatliquoring and dyeing of animal hides, being particularly useful for mineral (chromium) and vegetable tanning processes. The tanning agents are able to penetrate rapidly into the hide, driven by lyotropic swelling due to their high ionic strength. The samples are shown to have similar tanning agent content to the currently used aqueous chromium(III) sulfate solution; however, the waste metal content is shown to be significantly reduced. Incorporation of the DES Ethaline into the leather significantly alters the swelling properties of the leather increasing the flexibility and ductility of the material, therefore acting in the same manner as a fatliquor that lubricates or plasticizes the fibrous structure of the collagen. Ethaline was also used to transport a lysochromic dye throughout the cross section of the leather, and the hydrophobicity of the dye prevents leaching into the aqueous wash solution. Physical measurements show that leather processed using DESs have similar mechanical properties to that processed using conventional aqueous systems

Rodent models of focal cerebral ischemia: procedural pitfalls and translational problems

Rodent models of focal cerebral ischemia are essential tools in experimental stroke research. They have added tremendously to our understanding of injury mechanisms in stroke and have helped to identify potential therapeutic targets. A plethora of substances, however, in particular an overwhelming number of putative neuroprotective agents, have been shown to be effective in preclinical stroke research, but have failed in clinical trials. A lot of factors may have contributed to this failure of translation from bench to bedside. Often, deficits in the quality of experimental stroke research seem to be involved. In this article, we review the commonest rodent models of focal cerebral ischemia - middle cerebral artery occlusion, photothrombosis, and embolic stroke models - with their respective advantages and problems, and we address the issue of quality in preclinical stroke modeling as well as potential reasons for translational failure