A positioning pillow to improve lumbar puncture success rate in paediatric haematology-oncology patients: a randomized controlled trial

<p>Abstract</p> <p>Background</p> <p>Lumbar punctures (LPs) are common in children with cancer. Although pain management during the lumbar puncture has been well standardized, dealing with stress and anxiety is not well addressed yet. Our objective was to evaluate the potential improvement of the LP success rate using a positioning pillow, to ensure maximum lumbar flexion, and allow paravertebral muscles to relax, in children who are awake, with either conscious sedation or no sedation.</p> <p>Methods</p> <p>Children aged 2–18 years undergoing LP were randomly assigned to a positioning pillow or no intervention. The primary outcome was the rate of success, i.e. achieving the LP (sampling or injection) at the first attempt, without bleeding (RBC < 50/mm³). The secondary outcomes included: the child's pain, assessed by a self-administered visual analogical scales (VAS) for children over 6 years of age; the parents' and caregivers' perception of the child's pain; the satisfaction of the children, the parents, the caregivers and the physician. The child's cooperation and the occurrence of post-LP syndrome were also evaluated.</p> <p>Results</p> <p>124 children (62 in each group) were included. The LP pillow tended to increase the success rate of LPs (67% vs. 57%, p = 0.23), and decreased the post-LP syndromes (15% vs. 24%, p = 0.17) but the differences were not statistically significant. In children over 6-year of age (n = 72), the rate of success was significantly higher in the pillow group (58.5% vs. 41.5%, p = 0.031), with a tendency to feel less pain (median VAS 25 vs. 15 mm, p = 0.39) and being more satisfied (84.4% vs. 75.0%, p = 0.34).</p> <p>Conclusion</p> <p>Overall results do not demonstrate a benefit in using this pillow for lumbar punctures. This study results also suggest a benefit in the sub group of children over 6-year of age; this result needs confirmation.</p> <p>Trial Registration</p> <p>The trial was registered with Clinical Trials.gov (number NCT00775112).</p

m-AAA protease-driven membrane dislocation allows intramembrane cleavage by rhomboid in mitochondria

Maturation of cytochrome c peroxidase (Ccp1) in mitochondria occurs by the subsequent action of two conserved proteases in the inner membrane: the m-AAA protease, an ATP-dependent protease degrading misfolded proteins and mediating protein processing, and the rhomboid protease Pcp1, an intramembrane cleaving peptidase. Neither the determinants preventing complete proteolysis of certain substrates by the m-AAA protease, nor the obligatory requirement of the m-AAA protease for rhomboid cleavage is currently understood. Here, we describe an intimate and unexpected functional interplay of both proteases. The m-AAA protease mediates the ATP-dependent membrane dislocation of Ccp1 independent of its proteolytic activity. It thereby ensures the correct positioning of Ccp1 within the membrane bilayer allowing intramembrane cleavage by rhomboid. Decreasing the hydrophobicity of the Ccp1 transmembrane segment facilitates its dislocation from the membrane and renders rhomboid cleavage m-AAA protease-independent. These findings reveal for the first time a non-proteolytic function of the m-AAA protease during mitochondrial biogenesis and rationalise the requirement of a preceding step for intramembrane cleavage by rhomboid

Identification of conjugation specificity determinants unmasks vestigial preference for ubiquitin within the NEDD8 E2

Ubiquitin-like proteins (UBLs) modify targets via related E1-E2-E3 cascades. How is UBL conjugation fidelity established? Here we report the basis for UBL selection by UBL conjugating enzyme 12 (Ubc12), which is specific for the neural precursor cell expressed, developmentally down-regulated protein 8 (NEDD8), and does not form a thioester-linked conjugate with ubiquitin. We systematically identified Ubc12 surfaces impeding Ubc12 similar to ubiquitin conjugate formation and found that several structurally dispersed E1 binding elements, rather than UBL-interacting surfaces, determine E2 similar to UBL specificity. In addition to roles for conserved E1 and E2 domains, unique structures contribute UBL specificity to the NEDD8 and ubiquitin pathways. By removing surface elements, without substituting corresponding sequences from ubiquitin E2s, we unmasked Ubc12's vestigial preference for ubiquitin over NEDD8 by similar to 10(10)-fold. This has implications for the evolution of specific functions among ubiquitin E2s. We also find that Ubc12 sequences dictating UBL selection map to the E3 binding site, thus providing a molecular mechanism preventing inappropriate modification of targets