Detection of Highly Pathogenic Avian Influenza Virus H5N1 Clade 2.3.4.4b in Great Skuas:A Species of Conservation Concern in Great Britain

The UK and Europe have seen successive outbreaks of highly pathogenic avian influenza across the 2020/21 and 2021/22 autumn/winter seasons. Understanding both the epidemiology and transmission of these viruses in different species is critical to aid mitigating measures where outbreaks cause extensive mortalities in both land- and waterfowl. Infection of different species can result in mild or asymptomatic outcomes, or acute infections that result in high morbidity and mortality levels. Definition of disease outcome in different species is of great importance to understanding the role different species play in the maintenance and transmission of these pathogens. Further, the infection of species that have conservation value is also important to recognise and characterise to understand the impact on what might be limited wild populations. Highly pathogenic avian influenza virus H5N1 clade 2.3.4.4b has been detected in great skuas (Stercorarius skua) across different colonies on islands off the shore of Scotland, Great Britain during summer 2021. A large number of great skuas were observed as developing severe clinical disease and dying during the epizootic and mortalities were estimated to be high where monitored. Of eight skuas submitted for post-mortem examination, seven were confirmed as being infected with this virus using a range of diagnostic assays. Here we overview the outbreak event that occurred in this species, listed as species of conservation concern in Great Britain and outline the importance of this finding with respect to virus transmission and maintenance

The effects of endothermal ablation devices on the vein wall : a histological and immunohistochemical examination.

Varicose veins, often thought as a purely cosmetic issue, are a common symptom resulting from chronic venous insufficiency (CVI). CVI can result in serious fasciocutaneous and haematological complications. In 2013, NICE recommended that the treatment of varicose veins should preferably be carried out by endothermal ablation (ETA). The mechanism of action of ETA is still not fully understood. In 2004 it was suggested that successful treatment must involve transmural vein wall death (TMVD) in the target vein. Through the development of a novel in-vitro¬ model, using ex-vivo veins, the work carried out in this thesis has indicated that TMVD is reliant on a combination of thermal necrosis, followed by the upregulation of apoptosis. The novel model has been used to compare four different ETA techniques; endovenous laser ablation (EVLA) using an 810nm endovenous laser (EVL) with a jacketed fibre, EVLA using a 1470nm EVL with a jacketed fibre, EVLA using a 1470nm EVL with a radial fibre and Radiofrequency-induced Thermo Therapy (RFiTT). The comparisons indicate that treatment with the 810nm EVL is inferior at causing TMVD, in comparison to the 1470nm EVL. Treatment with a radial fibre, compared to a jacketed fibre, when using a 1470nm EVL, shows an improved damage profile that is much more homogenous with less overtreatment of target tissue. Comparisons between RFiTT and EVLA, indicate that treatment with RFiTT is as effective at causing TMVD as the 1470nm EVL with a radial fibre but with differences in the thermal damage profile. These results correlate well with reports from the current literature. However, this novel model has been able to show that the upregulation of apoptosis plays a pivotal role in TMVD after ETA treatment. The results also show that histology is often not sufficient to alone determine the difference between successful and inadequate treatment

Magnetite authigenesis and the warming of early Mars

The Curiosity rover has documented lacustrine sediments at Gale Crater, but how liquid water became physically stable on the early Martian surface is a matter of significant debate. To constrain the composition of the early Martian atmosphere during sediment deposition, we experimentally investigated the nucleation and growth kinetics of authigenic Fe-minerals in Gale Crater mudstones. Experiments show that pH variations within anoxic basaltic waters trigger a series of mineral transformations that rapidly generate magnetite and H2(aq). Magnetite continues to form through this mechanism despite high partial pressure of carbon dioxide (pCO2) and supersaturation with respect to Fe-carbonate minerals. Reactive transport simulations that incorporate these experimental data show that groundwater infiltration into a lake equilibrated with a CO2-rich atmosphere can trigger the production of both magnetite and H2(aq) in the mudstones. H2(aq), generated at concentrations that would readily exsolve from solution, is capable of increasing annual mean surface temperatures above freezing in CO2-dominated atmospheres. We therefore suggest that magnetite authigenesis could have provided a short-term feedback for stabilizing liquid water, as well as a principal feedstock for biologically relevant chemical reactions, at the early Martian surface

Magnetite authigenesis and the warming of early Mars

The Curiosity rover has documented lacustrine sediments at Gale Crater, but how liquid water became physically stable on the early Martian surface is a matter of significant debate. To constrain the composition of the early Martian atmosphere during sediment deposition, we experimentally investigated the nucleation and growth kinetics of authigenic Fe-minerals in Gale Crater mudstones. Experiments show that pH variations within anoxic basaltic waters trigger a series of mineral transformations that rapidly generate magnetite and H2(aq). Magnetite continues to form through this mechanism despite high partial pressure of carbon dioxide (pCO2) and supersaturation with respect to Fe-carbonate minerals. Reactive transport simulations that incorporate these experimental data show that groundwater infiltration into a lake equilibrated with a CO2-rich atmosphere can trigger the production of both magnetite and H2(aq) in the mudstones. H2(aq), generated at concentrations that would readily exsolve from solution, is capable of increasing annual mean surface temperatures above freezing in CO2-dominated atmospheres. We therefore suggest that magnetite authigenesis could have provided a short-term feedback for stabilizing liquid water, as well as a principal feedstock for biologically relevant chemical reactions, at the early Martian surface

Histological and Immunofluorescent Analysis of a Large Tributary of the Great Saphenous Vein Treated with a 1920 nm Endovenous Laser: Preliminary Findings

Objectives: To analyse the biological effects of a 1920 nm endovenous laser (EVL) on extra-fascial great saphenous vein (GSV) in vitro. Methods: A 10 cm length of a large tributary bypassing a hypoplastic segment of the GSV (sometimes called an “extra-fascial GSV”) was obtained during routine varicose vein surgery. The length was treated in five sections with different LEEDs (0 (control), 20, 40, 60, and 80 J/cm) with a 1920 nm EVL at 4W power, in a novel in vitro treatment model. The biological effects were assessed by histological staining of the samples for haematoxylin and eosin (HE) and Martius Scarlet Blue (MSB), and by immunofluorescent detection of p-p53 and VCAM-1. Results: Histological analysis showed significant structural damage at LEEDs above 60 J/cm, especially in the intima and media, with the treatment at 80 J/cm causing perforation of the vein wall. In addition, there was a significant increase in p-p53 expression in treated tissue at 60 and 80 J/cm. Conclusions: Using this ex vivo model, the results indicate that in vitro treatment with a 1920 nm EVL, at or above an LEED of 60 J/cm and 4 W power, causes significant vein wall cell death reaching deep into the media by a combination of direct thermal damage and apoptosis. A wavelength of 1920 nm appears to be effective for the endovenous ablation of truncal veins.</p