Biology subjects

Taggart, M.

Publications and source records attributed to Taggart, M..

4 recordsLinked to original sources

bioRxiv2023

Comparison of concentrations of lead (Pb) in meat from wild-shot common pheasants killed using shotgun pellets principally composed of lead, iron (Fe), bismuth (Bi) and zinc (Zn)

The source of almost all of the lead (Pb) found in meat from carcasses of wild-shot small game animals is often thought to be small embedded fragments of the lead shotgun pellets usually used by hunters to kill them. Available circumstantial evidence supports this conjecture, but an unknown proportion of the lead in game meat might be biologically-incorporated and absorbed by the game animal from ingested shotgun pellets and other environmental sources, such as soil and residues from mining. A critical test comparing lead concentrations in meat from animals known to have been killed using different types of shotgun ammunition has not been performed until now. We compared lead concentrations in samples of edible meat from carcasses of 27 wild-shot common pheasants (Phasianus colchicus) from which only lead shotgun pellets were recovered post mortem with concentrations for 20 birds from which only iron pellets were recovered. Shotgun pellets were removed from the meat samples before analysis. The mean concentration of lead was about 30 times greater in the meat of pheasants shot with lead than those shot with iron and was similar to mean concentrations of lead reported previously from Europe-wide samples of meat from wild-shot small game animals, including pheasants, killed using unknown types of ammunition. These results support the hypothesis that changing the type of shotgun ammunition in use for hunting from lead to iron would greatly reduce the concentration of lead in meat from wild-shot small game.

pharmacology and toxicology↗

bioRxiv2022

Implications for food safety of the size and location of fragments of lead shotgun pellets embedded in hunted carcasses of small game animals intended for human consumption

Carcasses of common pheasants (Phasianus colchicus) killed by hunters using shotguns are widely used or sold in the United Kingdom and elsewhere for human consumption. Almost all of the birds are shot using shotgun pellets composed principally of lead (Pb). Lead shotgun pellets often fragment on impact within the bodies of gamebirds, leaving small lead particles in the meat that are difficult for consumers to detect and remove and from which a greater proportion of lead is likely to be absorbed. Chronic exposure to even low levels of lead is associated with negative health effects in humans and especially in groups particularly vulnerable to the effects of lead, which include young children and pregnant women. Our study used a high-resolution computerised tomography X-ray scanner to locate, in three dimensions, metal fragments embedded within carcasses of eight pheasants sold for human consumption in the UK. Small radio-dense fragments (<2 mm diameter), assumed to be metallic lead, were present in all of the pheasant carcasses examined (mean number: 39 per carcass) and many were too small (<0.1 mm diameter) and too distant from the nearest large shotgun pellet for it to be practical for consumers to detect and remove them without discarding a large proportion of otherwise usable meat. Consumers of carcasses of pheasants killed using lead shotgun ammunition are likely to be exposed to elevated levels of dietary lead, even if careful food preparation is practiced to remove shotgun pellets and the most damaged tissue.

pharmacology and toxicology↗

bioRxiv2020

Clearance of senescent cells during cardiac ischemia-reperfusion injury improves heart recovery following myocardial infarction

A key component of cardiac ischemia-reperfusion injury (IRI) is the increased generation of reactive oxygen species, leading to enhanced inflammation and tissue dysfunction in patients following intervention for myocardial infarction. In this study we hypothesized that oxidative stress, due to ischemia-reperfusion, induces senescence which contributes to the pathophysiology of cardiac IRI. We demonstrate that IRI induces cellular senescence in both cardiomyocytes and interstitial cell populations and treatment with the senolytic drug navitoclax after ischemia-reperfusion improves left ventricular function, increases myocardial vascularization, and decreases scar size. SWATH-MS based proteomics reveal that biological processes associated with fibrosis and inflammation, that were increased following ischemia-reperfusion, were attenuated upon senescent cell clearance. Furthermore, navitoclax treatment reduced the expression of proinflammatory, profibrotic and anti-angiogenic cytokines, including interferon gamma-induced protein-10, TGF-{beta}3, interleukin-11, interleukin-16 and fractalkine. Our study provides proof-of-concept evidence that cellular senescence contributes to impaired heart function and adverse remodeling following cardiac ischemia-reperfusion. We also establish that post-IRI senescent cells play a considerable role in the inflammatory response. Subsequently, senolytic treatment, at a clinically feasible time point, attenuates multiple components of this response and improves clinically important parameters. Thus, cellular senescence represents a potential novel therapeutic avenue to improve patient outcomes following cardiac ischemia-reperfusion.

cell biology↗

bioRxiv2017

A Guide To Analysis And Reconstruction Of Serial Block Face Scanning Electron Microscopy Data

Serial block face scanning electron microscopy (SBF-SEM) is a relatively new technique that allows the acquisition of serially sectioned, imaged and digitally aligned ultrastructural data. There is a wealth of information that can be obtained from the resulting image stacks but this presents a new challenge for researchers - how to computationally analyse and make best use of the large data sets produced. One approach is to reconstruct structures and features of interest in 3D. However the software programs can appear overwhelming, time consuming and not intuitive for those new to image analysis. There are a limited number of published articles that provide sufficient detail on how to do this type of reconstruction. Therefore the aim of this paper is to provide a detailed step-by-step protocol, videos and explanation on the types of analysis and programs that can be used. To showcase the programs, skeletal muscle from fetal and adult guinea pigs were used. The tissue was processed using the heavy metal protocol developed specifically for SBFSEM. Trimmed resin blocks were placed into a Zeiss Sigma SEM incorporating the Gatan 3View and the resulting image stacks were analysed in 3 different programs, Fiji, Amira and MIB, using a range of tools available for segmentation. The results from the image analysis comparison show that the analysis tools are often more suited to a type of structure. For example larger structures, such as nuclei and cells, can be segmented using interpolation, which speeds up analysis; single contrast structures, such as the nucleolus, can be segmented using the contrast-based thresholding tools. Knowing the nature of the tissue and its specific structures (complexity, contrast, if there are distinct membranes, size) will help to determine the best method for reconstruction and thus maximising output from valuable tissue.

cell biology↗