Moreover, the pH controls the rate of lactate uptake from blood by hypoxic skeletal muscles. In this descriptive study, we did not analyze the subgroups derived from the combinations of mixed acid-base disorders and hydro-electrolyte disturbances because the number of patients was not sufficient to guarantee a significant statistical power for this purpose Probably the descriptive design of the study does not allow us to obtain definitive conclusions, but we strongly believe to have investigate a field not yet explored, eventually stimulating further prospective multicentric studies in order to completely clarify this topic, which recurs frequently in clinical practice. Our preliminary results suggest, in fact, that in the clinical respiratory care researchers should address the following questions: a) whether lactate clearance is useful during acute respiratory failure to identify patients at high risk of negative outcomes and, potentially, to increase the intensity of the therapeutic approach; b) whether lactate clearance is predictive of positive outcome and could confirm to physicians that the current therapeutic approach is appropriate; and c) how both the metabolic components of mixed acid-base disorders and the hydroelectrolyte balance alterations may worsen the hypercapnic respiratory failure caused by the COPD exacerbation and may affect its resolution through standard medical therapy, either alone or combined with NIV. Prion diseases are fatal neurodegenerative diseases in humans and animals. Most prominent examples are scrapie in sheep, bovine spongiform encephalopathy in cattle, chronic wasting disease in deer and Creutzfeldt-Jakob disease in humans. A characteristic feature of prion diseases is the accumulation of a pathological isoform of the host-encoded prion protein. Whereas the cellular isoform, PrPC, is soluble in mild detergents, the pathological isoform, PrPSc, forms insoluble aggregates. While PrPC is highly sensitive to complete digestion with proteinase K, PrPSc is only N-terminally truncated leaving the C-terminal part undigested with high retention of infectivity. Thus, PrPSc embodies both a PKresistant and a PK-sensitive portion; both moieties form aggregates, and neither can be detected in UNC2881 uninfected animals or humans. According to the prion hypothesis Citiolone proposed by Stanley Prusiner, PrPSc is, by itself, the agent of this class of transmissible diseases. The prion hypothesis has now been strongly corroborated by recent demonstrations of infectivity in particles prepared in vitro from recombinant PrP, though the PrP conformation bearing infectivity still has to be clarified.