Effect of intrabronchial platelet rich plasma on the exercise-induced pulmonary hemorrhage endoscopic score in thoroughbred racehorses using furosemide: a preliminary study

ABSTRACT The high prevalence of exercise-induced pulmonary hemorrhage (EIPH) in athletic horses constitutes to be a challenge to the racing industry and a source of major concern to animal welfare. Both experimental and clinical evidence indicate that the use of autologous platelet-rich plasma (PRP) is a promising effector of repair in a variety of pulmonary conditions. The present study evaluated the effect of intrabronchial instillation of PRP on EIPH endoscopic scores from 37 Thoroughbred racehorses. Inclusion criteria were for animals to be EIPH-positive in, at least, two consecutive post-exercise endoscopic exams and to receive 250mg of furosemide IV four hours before racing. Animals were randomly assigned into 3 groups: placebo, control, and PRP instillation. All 37 Thoroughbred racehorses included had EIPH endoscopic scores pre- and post- treatment compared by statistical analysis. The bleeding score from the group receiving PRP was significantly lower than in the control and placebo groups. No adverse effects were observed in any animal during or after the experiment. It was possible to conclude that the intrabronchial instillation of autologous PRP was effective in reducing EIPH scores in racehorses receiving furosemide and that this bioproduct can be considered as a promising coadjuvant in controlling EIPH in athletic horses.

Mobility versus retention of mercury in bare and salt marsh sediments of a recovering coastal lagoon (Ria de Aveiro, Portugal)

During decades, mercury (Hg) was discharged into the Aveiro Lagoon. Twenty-five years after the cessation of discharges, sediment cores were collected at two areas to assess the evolution of the mercury contamination status. Vertical Hg profiles differed considerably between bare and vegetated sediments. Bare sediments contained significantly less Hg (<8 mg kg^-1) than historical data of 1995 (up to 40 mg kg^-1), probably resulting from erosion. Salt marsh sediments were marked by a Hg sub-surface enrichment, reaching 44 mg kg^-1 in the site closer to the industrial discharge point. High Hg concentrations in 2007, 2011 and 2016 were found at similar sediment layers. These results emphasise the role of halophyte plants in the cycling and retention of Hg in sediments. The persistency of high Hg in the upper marsh layers highlights the complexity in the recovery of historically contaminated marshes and the vulnerability to modifications in hydrology associated with climate changes.

Cholesterol affects African swine fever virus infection

African swine fever virus (ASFV) enters cells by receptor mediated endocytosis and requires a fusion event between the viral envelope and the limiting membrane of the endosome at low pH. In order to investigate the role of cholesterol in the early stages of ASFV infection, we have studied the effect of the removal of cell and viral membrane cholesterol by cholesterol oxidase treatment of cells and virions, as well as the effect of some inhibitors of cholesterol synthesis on the infectious pathway. In addition, we have investigated viral infection in cholesterol-depleted Vero cells. Both cholesterol-depleted and cholesterol oxidase-treated Vero cells were unaltered in their ability to bind or internalize the virus, but were blocked in ASFV fusion and subsequent virus replication. Our results indicate that ASFV infection is affected by cholesterol in the target membrane.

Entry of African swine fever virus into Vero cells and uncoating

African swine fever virus (ASFV) enters Vero cells by adsorptive endocytosis [Valdeira, M.L., Geraldes, A., 1985. Morphological study on the entry of African swine fever virus into cells, Biol Cell. 55, 35-40]. Electron microscopy of a lysosomotropic drug-controlled penetration indicated that this step takes place in the endosomes, after fusion between the viral envelope and the limiting membrane of the endosome. Inhibition studies with colcemid, cytochalasin B, sodium azide, dinitrophenol, lysosomotropic weak bases, and the ionophore monensin, showed that the virus uptake is largely independent of cytoskeletal and lysosomal function, but dependent on oxidative phosphorylation. Some protease inhibitors inhibited viral replication at an early step, indicating that the initiation of infection depends on a viral proteolytic cleavage.

Fusion activity of African swine fever virus towards target membranes: lipid dependence and effect of dehydrating agents

Fusion of African swine fever virus (ASFV) with model membranes was monitored by a fluorescence dequenching assay. ASFV was able to fuse with liposomes of various compositions. Fusion was more extensive with liposomes made of negatively charged phospholipids, and reduced in the presence of the neutral phospholipid phosphatidylcholine (PC). Fusion activity of ASFV was pH-dependent, the extent of fusion increasing with decreasing pH for all target membranes. These results are consistent with the in vivo characteristics of fusion of ASFV with the endosome membrane. An increase in fusion activity was obtained with dehydrating agents, similarly to what occurs with other lipid-enveloped viruses. Dehydrating agents such as dimethylsulfoxide and dimethylsulfone greatly enhanced fusion, the effect of dimethylsulfone being more pronounced than that of dimethylsulfoxide. Poly(ethylene glycol) also potentiated ASFV fusion activity, and the effect of this polymer was found to be dependent on its molecular weight. These results stress the importance of dehydration and hydrophobic interactions on the early events of viral penetration into target cells.