Effects of bilateral lung transplantation on cardiac autonomic modulation and cardiorespiratory coupling: a prospective study.

BACKGROUND: Although cardiac autonomic modulation has been studied in several respiratory diseases, the evidence is limited on lung transplantation, particularly on its acute and chronic effects. Thus, we aimed to evaluate cardiac autonomic modulation before and after bilateral lung transplantation (BLT) through a prospective study on patients enrolled while awaiting transplant. METHODS: Twenty-two patients on the waiting list for lung transplantation (11 women, age 33 [24-51] years) were enrolled in a prospective study at Ospedale Maggiore Policlinico Hospital in Milan, Italy. To evaluate cardiac autonomic modulation, ten minutes ECG and respiration were recorded at different time points before (T0) and 15 days (T1) and 6 months (T2) after bilateral lung transplantation. As to the analysis of cardiac autonomic modulation, heart rate variability (HRV) was assessed using spectral and symbolic analysis. Entropy-derived measures were used to evaluate complexity of cardiac autonomic modulation. Comparisons of autonomic indices at different time points were performed. RESULTS: BLT reduced HRV total power, HRV complexity and vagal modulation, while it increased sympathetic modulation in the acute phase (T1) compared to baseline (T0). The HRV alterations remained stable after 6 months (T2). CONCLUSION: BLT reduced global variability and complexity of cardiac autonomic modulation in acute phases, and these alterations remain stable after 6 months from surgery. After BLT, a sympathetic predominance and a vagal withdrawal could be a characteristic autonomic pattern in this population.

Influence of MA internal sequences, but not of the myristylated N-terminus sequence, on the budding site of HIV-1 Gag protein.

HIV-1 Gag protein intracellular transport and budding was investigated by altering the sequence of the MA domain, which directly bears an essential N-terminal myristyl adduct and forms the viral matrix after Gag proteolysis in mature virions. We found that removal of a substantial MA internal segment did not abolish the assembly and budding of Gag particles, but rather diverted these events to intracellular cisternae. The internally deleted Gag was further modified by substituting either of two heterologous myristylated N-termini for the natural one: amino acids 1-12 from v-Src oncoprotein (for which a membrane-bound intracellular receptor has been postulated), or amino acids 1-12 from Poliovirus polyprotein (for which no membrane-targeting function has been demonstrated). Both Src-Gag and Polio-Gag chimerae exhibited transport and processing characteristics similar to those of the MA-deleted Gag. These results are discussed with respect to the possible transport pathway of HIV-1 Gag.