A 13-month-old Sphynx cat was referred for patent ductus arteriosus (PDA) ligation. A left thoracotomy was performed and the PDA was efficiently ligated. Immediately after chest tube placement, it presented extensive intrathoracic bleeding from the caudal intercostal artery. In view of the absolute necessity of a blood transfusion and given that compatible feline blood was not available, xenotransfusion of canine blood was administered to the cat and resulted in a positive outcome.

NMR magnetization transfer from water and ammonia-catalyzed exchange of the imino proton have been used to probe enhanced thermostability and conformational rearrangements induced by Mg 2+ in two key activity fragments r(CACCUGGCGACAG GUG) and r(GGCCAAAAGCC) of the encephalomyocarditis virus (EMCV) picornavirus internal ribosome entry site (IRES). We have measured some of their r(G · C) base-pair lifetimes and dissociation constants under different MgCl 2 conditions, and we compare them with those of other short RNA duplexes. The RNA fragment r(CACCUGGCGACAGGUG) adopts two topologies, a palindromic duplex with two conformations and a hairpin, whose equilibrium can be monitored: the duplex form is destabilized by Mg 2+ and temperature, a delicate balance wherein the entropic contribution of the free energy helps populate the hairpin state. For both fragments, the opening rates of the r(G · C) pairs are lower in the presence of Mg 2+ and their dissociation constants are smaller or comparable. Analysis of the results suggests that Mg 2+ has a preferential and specific effect on the r(CACCU GGCGACAGGUG) hairpin in the region close to the r(G · C) closing pair of the GCGA tetraloop, and the ion moves diffusively around r(GGCCAAAAGCC), thereby differentiating the GNRA and RAAA hairpin motifs that are both involved in the biological regulation functions of the EMCV IRES.Keywords Base-pair kinetics · EMCV IRES · GNRA tetraloop · Imino proton exchange · Mg 2+ · NMR · RAAA hairpin motif

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Horses are susceptible to developing large areas of pulmonary atelectasis during recumbency and anesthesia. The subsequent pulmonary shunt is responsible for significant impairment of oxygenation. Since ventilation perfusion mismatch persists into the post-operative period, hypoxemia remains an important concern in the recovery stall. This case report describes the diagnosis and supportive therapy of persistent hypoxemia in a 914 kg draft horse after isoflurane anesthesia. It highlights how challenging it can be to deal with hypoxemia after disconnection from the anesthesia machine and how life-threatening it can become if refractory to treatment. Furthermore, it stresses the point on the interactions between hypoxemia and other factors, such as residual drug effects and hypothermia, that should also be considered in the case of delayed recovery from general anesthesia.