Maximum thickness of subarachnoid blood is associated with mortality in patients with traumatic subarachnoid haemorrhage.

This study was designed to evaluate whether the maximum thickness of subarachnoid blood is an independent prognostic marker of mortality after traumatic subarachnoid haemorrhage. Multivariate analysis showed the maximum thickness of subarachnoid blood was an independent predictor of death versus survival 1 month after injury and was inversely associated with Glasgow Coma Scale (GCS) score. Receiver operating characteristic curve analysis showed that maximum thickness of subarachnoid blood > 6.7 mm immediately after non-surgical resuscitation predicted 1-month mortality with 83.9% sensitivity and 67.1% specificity; its predictive value was similar to that of the GCS score. Addition of maximum thickness of subarachnoid blood to the GCS score did not significantly improve predictive performance. Hence, the maximum thickness of subarachnoid blood is a new independent prognostic marker of mortality and might become an additional, valuable tool for risk stratification and decision making in the acute phase of traumatic subarachnoid haemorrhage.

Association of interleukin-11 with mortality in patients with spontaneous basal ganglia haemorrhage.

This study evaluated interleukin (IL)-11 as an independent prognostic marker of mortality following intracerebral haemorrhage (ICH). Plasma IL-11 levels in patients with ICH were significantly higher than in healthy controls. Multivariate analysis indicated that plasma IL-11 level was an independent predictor for mortality within 1 week of ICH onset and was positively associated with haematoma volume. Receiver operating characteristic curve analysis identified that a baseline plasma IL-11 level > 20.9 pg/ml predicted mortality within 1 week of ICH onset with 81.2% sensitivity and 74.1% specificity. The area under the curve for IL-11 level was significantly smaller than that for the Glasgow Coma Scale score, but similar to that for haematoma volume. IL-11 did not, however, significantly improve the predictive value of the Glasgow Coma Scale or haematoma volume. Thus, IL-11 may be considered as a new independent prognostic marker of mortality and an additional valuable tool for risk stratification and decision-making in the acute phase of ICH.

The L18 domain of light-harvesting chlorophyll proteins binds to chloroplast signal recognition particle 43.

Chloroplast signal recognition particle (cpSRP) is a novel type of SRP that contains a homolog of SRP54 and a 43-kDa subunit absent from all cytoplasmic SRPs but lacks RNA. It is also distinctive in its ability to post-translationally interact with light-harvesting chlorophyll proteins (LHCP), hydrophobic proteins synthesized in the cytoplasm and targeted to the thylakoid via the stroma. LHCP integration into thylakoid membranes requires the two subunits of cpSRP, cpFtsY, GTP, and the membrane protein ALB3. It had previously been shown that the L18 domain, an 18-amino acid peptide between the second and third transmembrane domains, and a hydrophobic domain are required for interaction with cpSRP. In the present study we used a pull-down assay, with cpSRP43 or cpSRP54 fused to glutathione-transferase, to study interactions between cpSRP43, cpSRP54, LHCP, and cpFtsY. cpFtsY was not observed to form significant interactions with any of the proteins even in the presence of nonhydrolyzable GTP analogs. Our data indicate that cpSRP43 binds to the L18 domain, that cpSRP54 binds to the hydrophobic domain, and that LHCP and cpSRP54 independently bind to cpSRP43. These data confirm that the novel post-translational interaction between LHCP and cpSRP is mediated through binding to cpSRP43.

Chloroplast FtsY, chloroplast signal recognition particle, and GTP are required to reconstitute the soluble phase of light-harvesting chlorophyll protein transport into thylakoid membranes.

The integration of light-harvesting chlorophyll proteins (LHCPs) into the thylakoid membrane proceeds in two steps. First, LHCP interacts with a chloroplast signal recognition particle (cpSRP) to form a soluble targeting intermediate called the transit complex. Second, LHCP integrates into the thylakoid membrane in the presence of GTP, at least one other soluble factor, and undefined membrane components. We previously determined that cpSRP is composed of 43- and 54-kDa polypeptides. We have examined the subunit stoichiometry of cpSRP and find that it is trimeric and composed of two subunits of cpSRP43/subunit of cpSRP54. A chloroplast homologue of FtsY, an Escherichia coli protein that is critical for the function of E. coli SRP, was found largely in the stroma unassociated with cpSRP. When chloroplast FtsY was combined with cpSRP and GTP, the three factors promoted efficient LHCP integration into thylakoid membranes in the absence of stroma, demonstrating that they are all required for reconstituting the soluble phase of LHCP transport.