Heat stress: A major contributor to poor animal welfare associated with long-haul live export voyages

Recent investigations by the Australian Department of Agriculture, Fisheries and Forestry into high mortalities on live export voyages from Australia to the Middle East during the Northern hemisphere summer suggest that animal welfare may be compromised by heat stress. The live export industry has generated a computer model that aims to assess the risk of heat stress and to contain mortality levels on live export ships below certain arbitrary limits. Although the model must be complied with under Australian law, it is not currently available for independent scientific scrutiny, and there is concern that model and the mandated space allowances are inadequate. This review appraises the relevant literature on heat stress in sheep and cattle, including laboratory studies aimed at mimicking the ambient temperatures and humidity levels likely to be encountered on live export voyages. Animal welfare is likely to be very poor as a result of heat stress in some shipments

Complement lectin pathway activation is associated with COVID-19 disease severity, independent of MBL2 genotype subgroups

IntroductionWhile complement is a contributor to disease severity in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections, all three complement pathways might be activated by the virus. Lectin pathway activation occurs through different pattern recognition molecules, including mannan binding lectin (MBL), a protein shown to interact with SARS-CoV-2 proteins. However, the exact role of lectin pathway activation and its key pattern recognition molecule MBL in COVID-19 is still not fully understood.MethodsWe therefore investigated activation of the lectin pathway in two independent cohorts of SARS-CoV-2 infected patients, while also analysing MBL protein levels and potential effects of the six major single nucleotide polymorphisms (SNPs) found in the MBL2 gene on COVID-19 severity and outcome.ResultsWe show that the lectin pathway is activated in acute COVID-19, indicated by the correlation between complement activation product levels of the MASP-1/C1-INH complex (p=0.0011) and C4d (p<0.0001) and COVID-19 severity. Despite this, genetic variations in MBL2 are not associated with susceptibility to SARS-CoV-2 infection or disease outcomes such as mortality and the development of Long COVID.ConclusionIn conclusion, activation of the MBL-LP only plays a minor role in COVID-19 pathogenesis, since no clinically meaningful, consistent associations with disease outcomes were noted

The role of thromboxane in verminous arteritis in horses

Severe mesenteric arteritis and thrombosis in horses produced by immature stages of the nematode parasite S. vulgaris can be accompanied by intestinal pain or colic. The pain is thought to result from intestinal ischaemia although the cause of ischaemia in naturally infected animals is unknown. Widespread embolisation is not a feature of the natural disease and the equine gut has unique anatomical features allowing compensation for occlusion of major vessels. Most infected animals are asymptomatic. The work presented in this thesis results from an investigation of the hypothesis that thromboxane A2 (TXA2) produced by blood platelets may be important in the pathophysiology of clinical verminous arteritis. TXA2 is a powerful vasoconstrictor of blood vessels from many anatomical sites in a variety of species. Its other major biological property is enhancement of intravascular thrombosis by both direct activation of platelets and synergism with other platelet agonists. The aim of the first aspect of the study was to establish whether peripheral levels of TXB2 (the stable breakdown product of TXA2) were elevated in animals experimentally infected with S. vulgaris. A radioimmunoassay was validated for use in unextracted horse plasma and levels in non-infected animals were found to be low. A total of 11 animals were studied, comprising 4 foals raised parasite free, 2 conventionally reared foals and 5 conventionally reared yearling horses. Lesions of severe arteritis were present at post mortem examination of all 6 foals but concurrent rises in TXB2 were not found. The yearling animals showed resistance to infection with only 1 developing arteritis. This animal was also clinically affected and mean levels of TXB2 after infection were significantly greater than in the control period. Evidence for continuous TXA2 production could not be demonstrated, but significant local production of TXA2 within affected arteries seemed likely. The effects of vasoconstrictors on isolated strips of mesenteric and digital arteries and veins were compared to those produced by the stable endoperoxide/TXA2 analogue U46619. Contractions of equine digital arteries and veins were comparable to those produced by noradrenaline but equine mesenteric arteries were unresponsive to the endoperoxide analogue. Similar results were obtained in isolated perfused equine mesentery and hoof. The effects of U46619, prostanoids, thromboxane synthase inhibiting drugs and thromboxane receptor antagonists on platelet aggregation were measured in vitro using a standard turbidimetric method. Unlike human platelets, equine platelets did not aggregate irreversibly in response to U46619 or arachidonic acid. Prostaglandins 12, D2 and E1 were found to be potent inhibitors of platelet aggregation. The in vitro platelet aggregation experiments indicated that the arachidonate pathway may be less important in equine platelet function than in some other species, notably man. The correlation between increased skin bleeding time, a simple measure of in vivo platelet function, and suppression of thromboxane generation by aspirin was established. Bleeding time returned to normal limits significantly faster than the recovery of thromboxane generating capacity in aggregating platelets, demonstrating the compensatory effects by other pathways of platelet activation. TXB2 has been reported to be chemotactic for inflammatory cells in other species and it was found to have weak chemotactic, but not chemokinetic, activity for equine isolated peripheral neutrophils and monocytes. The lack of response of equine mesenteric vessels and platelets to thromboxane analogue indicates that TXA2 alone is unlikely to account for intestinal ischaemia in horses with verminous arteritis. Measurement of peripheral TXB2 is not a reliable marker for platelet activation in infected animals. By contrast this mediator seems likely to contribute to abnormal blood flow in the hoof in conditions such as endotoxaemia, where production of TXA2 is known to be increased and laminitis is a common sequela

Biographies: Polar Explorers and Photographers

Find out about the men who led the polar expeditions, and the photographers who captured their journeys. Includes biographies of: Adams, William (Snr) (d. 1890), Bagshawe, Thomas Wyatt (1901-1976), Borchgrevink, Carsten Egeberg (1864-1934), Bruce, William Speirs (1867-1921), Byrd, Admiral Richard Evelyn (1888-1957), Carse, Verner Duncan (1913-2004), Crozier, Francis Rawdon Moira (1796-1848), Fiennes, Sir Ranulph (b. 1944), Franklin, Sir John (1786-1847), Giaever, John Schelderup (1901-1990), Gray, David (Jnr.) (1829-1896), Haig-Thomas, David (1908-1944), Hurley, James Francis [Frank] (1885-1962), Leigh Smith, Benjamin (1828-1913), Lester, Maxime Charles (1891-1957), Nares, Sir George Strong (1831-1915), Ponting, Herbert George (1870-1935), Rymill, John Riddoch (1905-1968), Scott, Captain Robert Falcon (1868-1912), Shackleton, Sir Ernest Henry (1874-1922), Watkins, Henry George [Gino] (1907-1932), Wild, John Robert Francis [Frank] (1874-1939).

Freeze Frame Resources

The Freeze Frame website presents an online catalogue of over 20,000 images from the historic negative collections at the Scott Polar Research Institute. The negatives cover expeditions into the Arctic and Antarctic during the period 1845-1982 and representing some of the most important visual resources for research into British and international polar exploration. These images are presented with ancillary material from the collections of the Institute, and critical essays contextualising much of the material. The resources section allows you to find out more about the environment of the polar regions, and read about the people and expeditions from which the Freeze Frame images are taken.

History of Photography in the Polar Regions

The word photograph was first used by Sir John Herschel in 1839 - it originates from the Greek words meaning light and writing. The Freeze Frame collection covers many of the key developments in photography, charting not only polar exploration but also the emergence of photography. This information resource briefly outlines the scientific developments in photography before looking specifically at photography in the polar regions.

Ice and Icebergs

The Freeze Frame website presents an online catalogue of over 20,000 images from the historic negative collections at the Scott Polar Research Institute. The negatives cover expeditions into the Arctic and Antarctic during the period 1845-1982 and representing some of the most important visual resources for research into British and international polar exploration. These images are presented with ancillary material from the collections of the Institute, and critical essays contextualising much of the material. This resource features a selection of images arranged around the theme of Ice and Icebergs.

Changing Britain and the Heroic Age

The heroic age of Antarctic Exploration is usually said to begin in the reign of King Edward VII (1901-1910), and is embodied by an outlook on life characterised by ‘muscular Christianity’ which emphasised daring and chivalry, as well as being prepared to make sacrifices for one’s country in undertaking heroic deeds. Setting off to discover the poles was another way men could ‘do their bit’ for Britain in the spirit of what was heroic and daring. This resource describes Britain During the Heroic Age, The Heroic Age of Exploration, Heroic Age Expeditions in the Freeze Frame Collection, The Death of Robert Falcon Scott, The Death of Ernest Shackleton and the End of the Heroic Age, Modern Views of the Heroic Age.

Wildlife in the Polar Regions

The Freeze Frame website presents an online catalogue of over 20,000 images from the historic negative collections at the Scott Polar Research Institute. The negatives cover expeditions into the Arctic and Antarctic during the period 1845-1982 and representing some of the most important visual resources for research into British and international polar exploration. These images are presented with ancillary material from the collections of the Institute, and critical essays contextualising much of the material. This resource features a selection of images arranged around the theme of polar wildlife.