Development of a two-stage limb ischemia model to better simulate human peripheral artery disease

Peripheral arterial disease (PAD) develops due to the narrowing or blockage of arteries supplying blood to the lower limbs. Surgical and endovascular interventions are the main treatments for advanced PAD but alternative and adjunctive medical therapies are needed. Currently the main preclinical experimental model employed in PAD research is based on induction of acute hind limb ischemia (HLI) by a 1-stage procedure. Since there are concerns regarding the ability to translate findings from this animal model to patients, we aimed to develop a novel clinically relevant animal model of PAD. HLI was induced in male Apolipoprotein E (ApoE(-/-)) deficient mice by a 2-stage procedure of initial gradual femoral artery occlusion by ameroid constrictors for 14 days and subsequent excision of the femoral artery. This 2-stage HLI model was compared to the classical 1-stage HLI model and sham controls. Ischemia severity was assessed using Laser Doppler Perfusion Imaging (LDPI). Ambulatory ability was assessed using an open field test, a treadmill test and using established scoring scales. Molecular markers of angiogenesis and shear stress were assessed within gastrocnemius muscle tissue samples using quantitative polymerase chain reaction. HLI was more severe in mice receiving the 2-stage compared to the 1-stage ischemia induction procedure as assessed by LDPI (p = 0.014), and reflected in a higher ischemic score (p = 0.004) and lower average distance travelled on a treadmill test (p = 0.045). Mice undergoing the 2-stage HLI also had lower expression of angiogenesis markers (vascular endothelial growth factor, p = 0.004; vascular endothelial growth factor-receptor 2, p = 0.008) and shear stress response mechano-transducer transient receptor potential vanilloid 4 (p = 0.041) within gastrocnemius muscle samples, compared to animals having the 1-stage HLI procedure. Mice subjected to the 2-stage HLI receiving an exercise program showed significantly greater improvement in their ambulatory ability on a treadmill test than a sedentary control group. This study describes a novel model of HLI which leads to more severe and sustained ischemia than the conventionally used model. Exercise therapy, which has established efficacy in PAD patients, was also effective in this new model. This new model maybe useful in the evaluation of potential novel PAD therapies

Reactive trityl derivatives: stabilised carbocation mass-tags for life sciences applications

The rational design of novel triarylmethyl (trityl)-based mass tags (MT) for mass-spectrometric (MS) applications is described. We propose a "pKR+ rule" to correlate the stability of trityl carbocations with their MS performance: trityls with higher pKR+ values ionise and desorb better. Trityl blocks were synthesised that have high pKR+ values and are stable in conditions of MS analysis; these MTs can be ionised by matrix as well as irradiation with a 337 nm nitrogen laser. 13C-Labelled tags were prepared for MS quantitation applications. Moreover, the tags were equipped with a variety of functional groups allowing conjugation with different functionalities within (bio)molecules to enhance the MS characteristics of the latter. The MS behaviour of model polycationic trityl compounds with and without the matrix was studied to reveal that poly-trityl clusters are always singly charged under the (MA)LDI-TOF conditions. Several peptide-trityl conjugates were prepared and comparisons revealed a beneficial effect of trityl tags on the conjugate detection in MS. Trityl compounds containing para-methoxy- and dimethylamine groups, as well as a xanthene fragment, showed considerable enhancement in MS detection of model peptides; thus they are promising tools for proteomic applications. Dimethoxytrityl derivatives allow one to distinguish between Arg- and Lys-containing peptides. Maleimido trityl derivatives are suitable for the efficient derivatisation of thiol-containing peptides in pyridine

A Critical Assessment of the Effects of Bt Transgenic Plants on Parasitoids

The ecological safety of transgenic insecticidal plants expressing crystal proteins (Cry toxins) from the bacterium Bacillus thuringiensis (Bt) continues to be debated. Much of the debate has focused on nontarget organisms, especially predators and parasitoids that help control populations of pest insects in many crops. Although many studies have been conducted on predators, few reports have examined parasitoids but some of them have reported negative impacts. None of the previous reports were able to clearly characterize the cause of the negative impact. In order to provide a critical assessment, we used a novel paradigm consisting of a strain of the insect pest, Plutella xylostella (herbivore), resistant to Cry1C and allowed it to feed on Bt plants and then become parasitized by Diadegma insulare, an important endoparasitoid of P. xylostella. Our results indicated that the parasitoid was exposed to a biologically active form of the Cy1C protein while in the host but was not harmed by such exposure. Parallel studies conducted with several commonly used insecticides indicated they significantly reduced parasitism rates on strains of P. xylostella resistant to these insecticides. These results provide the first clear evidence of the lack of hazard to a parasitoid by a Bt plant, compared to traditional insecticides, and describe a test to rigorously evaluate the risks Bt plants pose to predators and parasitoids

From the outside in: narratives of creative arts practitioners working in the criminal justice system

This is an accepted manuscript of an article published by Wiley-Blackwell in The Howard Journal of Crime and Justice on 31/12/2019, available online: https://doi.org/10.1111/hojo.12318 The accepted version of the publication may differ from the final published version.The penal voluntary sector is highly variegated in its roles, practices and functions, though research to date has largely excluded the experiences of front-line practitioners. We argue that engaging with the narratives of practitioners can provide fuller appreciation of the potential of the sector’s work. Though life story and narrative have been recognised as important in offender desistance (Maruna, 2001), the narrative identities of creative arts practitioners, who are important ‘change agents’ (Albertson, 2015), are typically absent. This is despite evidence to suggest that a practitioner’s life history can be a significant and positive influence in the rehabilitation of offenders (Harris, 2017). Using narratological analysis (Bal, 2009), this study examined the narratives of 19 creative practitioners in prisons in England and Wales. Of particular interest were the formative experiences of arts practitioners in their journey to prison work. The findings suggest that arts practitioners identify with an ‘outsider’ status and may be motivated by an ethic of mutual aid. In the current climate of third sector involvement in the delivery of criminal justice interventions, such a capacity may be both a strength and weakness for arts organisations working in this field

Synthesis of a Dihydroxylated Dienediyne Analogue Related to Neocarzinostatin Chromophore

A 12-step synthesis of a dihydroxylated dienediyne analogue related to Neocarzinostatin Chromophore is reported

Flavonols reduce aortic atherosclerosis lesion area in apolipoprotein E deficient mice: A systematic review and meta-analysis

<div><p>Diets rich in flavonoids have been reported to have beneficial effects in the primary prevention of cardiovascular events. There are limited data, however, on the cardiovascular benefits of purified flavonoids. The aim of this systematic review and meta-analysis was to examine the reported effects of isolated flavonoids on aortic atherosclerosis in a mouse model. Medline, Pubmed, Science direct and Web of Science were searched to identify studies which examined the effect of isolated flavonoids on aortic atherosclerosis in apolipoprotein E deficient mice. A meta-analysis was performed to determine the overall effect of the flavonoids, and sub-analyses were performed to compare the effects of the flavonols and flavan-3-ols. Eleven studies, which examined a total of 208 mice receiving a flavonoid and 126 control mice, were included. Overall the flavonoids significantly reduced aortic atherosclerosis (SMD 1.10, 95% CI 0.69, 1.51). Of the 18 flavonoid interventions examined 12 were flavonols and 3 were flavan-3-ols. Sub-analyses suggested that the flavonols (SMD 1.31, 95% CI 0.66, 1.91) but not the flavan-3-ols (SMD 0.33, 95% CI -0.19, 0.85) significantly decreased atherosclerosis area. Of the eleven studies, only one examined histological markers of atherosclerosis plaque stability. Most studies did not report blinding of outcome assessors or reproducibility of the primary outcome, and did not justify the sample size used and flavonoid dose administered. Based on the included studies, the flavonols appear to be the most effective flavonoids for reducing aortic atherosclerotic lesion area in apolipoprotein E deficient mice.</p></div

Structural basis for the binding of SNAREs to the multisubunit tethering complex Dsl1

Multisubunit tethering complexes (MTCs) are large (250 to >750 kDa), conserved macromolecular machines that are essential for SNARE-mediated membrane fusion in all eukaryotes. MTCs are thought to function as organizers of membrane trafficking, mediating the initial, long-range interaction between a vesicle and its target membrane and promoting the formation of membrane-bridging SNARE complexes. Previously, we reported the structure of the Dsl1 complex, the simplest known MTC, which is essential for COPI-mediated transport from the Golgi to the endoplasmic reticulum (ER). This structure suggested how the Dsl1 complex might function to tether a vesicle to its target membrane by binding at one end to the COPI coat and at the other end to ER SNAREs. Here, we use x-ray crystallography to investigate these Dsl1-SNARE interactions in greater detail. The Dsl1 complex comprises three subunits that together form a twolegged structure with a central hinge. Our results show that distal regions of each leg bind N-terminal Habc domains of the ER SNAREs Sec20 (a QbSNARE) and Use1 (a Qc-SNARE). The observed binding modes appear to anchor the Dsl1 complex to the ER target membrane while simultaneously ensuring that both SNAREs are in open conformations with their SNARE motifs available for assembly. The proximity of the two SNARE motifs, and therefore their ability to enter the same SNARE complex, depends on the relative orientation of the two Dsl1 legs

Properties of the major flavonoid classes (examples in brackets) used in atherosclerosis research in apolipoprotein E mice.

<p>Catechin and epicatechin are flavan-3-ols; Quercetin, Kaempferol and Isorhamnetin are flavonols; and EMIQ and myricitrin are flavonol glycosides. EMIQ, Enzymatically modified isoquercitrin; R, glucose chain (n = 3–9). Adapted from de Pascual-Teresa, Moreno [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0181832#pone.0181832.ref017" target="_blank">17</a>].</p

Effect of different flavonoids on atherosclerosis lesion area in ApoE^-/- mice and key aspects of the methods of the included studies.

<p>Effect of different flavonoids on atherosclerosis lesion area in ApoE^-/- mice and key aspects of the methods of the included studies.</p

Preferred Reporting Items of Systematic Review and Meta-analyses (PRISMA) flow diagram.

<p>A total of 1192 articles were identified from Science direct, Web of Science, Pubmed and Medline. Of these, 26 full-text articles were assessed for eligibility and 11 articles were included in the review. Eight studies were excluded as they did not measure atherosclerosis lesion area. One study was excluded as it administered a crude extract. Three studies were excluded because sample sizes could not be retrieved and three studies were excluded because of insufficient data for lesion area comparison. <i>From</i>: Mohar D, Liberati A, Tetzlaff J, Altman DG, The PRISMA Group (2009). <i>P</i>referred <i>R</i>eporting <i>I</i>tems for <i>S</i>ystematic Reviews and <i>M</i>eta-<i>A</i>nalyses: The PRISMA Statement. PLOS Med 6(7): e1000097. doi:<a href="https://doi.org/10.1371/journal.pmed1000097" target="_blank">10.1371/journal.pmed1000097</a> <b>For more information, visit</b> <a href="http://www.prisma-statement.org" target="_blank">www.prisma-statement.org</a>.</p