Background—In an apparent paradox morbidity and mortality are lower in obese patients undergoing cardiac surgery, although the nature of this association is unclear. We sought to determine whether the obesity paradox observed in cardiac surgery is attributable to reverse epidemiology, bias, or confounding. Methods—Data from the National Adult Cardiac Surgery registry for all cardiac surgical procedures performed between April 2002 and March 2013 were extracted. A parallel systematic review and meta-analysis (MEDLINE, Embase, SCOPUS, Cochrane Library) through June 2015 was also accomplished. Exposure of interest was body mass index (BMI) categorised into 6 groups according to the World Health Organisation classification. Results—A total of 401 227 adult patients in the cohort study, and 557 720 patients in the systematic review were included. A "U-shape" association between mortality and BMI classes was observed in both studies, with lower mortality in overweight (adjusted odds ratio [OR], 0.79; 95% confidence interval [CI], 0.76-0.83) and obese class I and II (OR, 0.81; 95%CI, 0.76-0.86 and OR, 0.83; 95%CI, 0.74-0.94) patients relative to normal weight patients and increased mortality in underweight individuals (OR, 1.51; 95%CI 1.41-1.62). In the cohort study, a "U-shaped" relationship was observed for stroke and low cardiac output syndrome, but not for renal replacement therapy or deep sternal wound infection. Counter to the reverse epidemiology hypotheses the protective effects of obesity were less in patients with severe chronic renal, lung or cardiac disease and greater in older patients, and in those with complications of obesity including the metabolic syndrome and atherosclerosis. Adjustments for important confounders did not alter our results. Conclusions—Obesity is associated with lower risks after cardiac surgery, with consistent effects noted in multiple analyses attempting to address residual confounding and reverse causation.

Generating the extended endoplasmic reticulum (ER) network depends on microtubules, which act as tracks for motor-driven ER tubule movement, generate the force to extend ER tubules by means of attachment to growing microtubule plus-ends and provide static attachment points. We have analysed ER dynamics in living VERO cells and find that most ER tubule extension is driven by microtubule motors. Surprisingly, we observe that ∼50% of rapid ER tubule movements occur in the direction of the centre of the cell, driven by cytoplasmic dynein. Inhibition of this movement leads to an accumulation of lamellar ER in the cell periphery. By expressing dominant-negative kinesin-1 constructs, we show that kinesin-1 drives ER tubule extension towards the cell periphery and that this motility is dependent on the KLC1B kinesin light chain splice form but not on KLC1D. Inhibition of kinesin-1 promotes a shift from tubular to lamellar morphology and slows down the recovery of the ER network after microtubule depolymerisation and regrowth. These observations reconcile previous conflicting studies of kinesin-1 function in ER motility in vivo. Furthermore, our data reveal that cytoplasmic dynein plays a role in ER motility in a mammalian cultured cell, demonstrating that ER motility is more complex than previously thought.

Cenp-F is an unusual kinetochore protein in that it localizes to the nuclear matrix in interphase and the nuclear envelope at the G2/M transition; it is farnesylated and rapidly degraded after mitosis. We have recently shown that farnesylation of Cenp-F is required for G2/M progression, its localization to kinetochores, and its degradation. However, the role Cenp-F plays in mitosis has remained enigmatic. Here we show that, following repression of Cenp-F by RNA interference (RNAi), the processes of metaphase chromosome alignment, anaphase chromosome segregation and cytokinesis all fail. Although kinetochores attach to microtubules in Cenp-F-deficient cells, the oscillatory movements that normally occur following K-fibre formation are severely dampened. Consistently, inter-kinetochore distances are reduced. In addition, merotelic associations are observed, suggesting that whereas kinetochores can attach microtubules in the absence of Cenp-F, resolving inappropriate interactions is inhibited. Repression of Cenp-F does not appear to compromise the spindle checkpoint. Rather, the chromosome alignment defect induced by Cenp-F RNA interference is accompanied by a prolonged mitosis, indicating checkpoint activation. Indeed, the prolonged mitosis induced by Cenp-F RNAi is dependent on the spindle checkpoint kinase BubR1. Surprisingly, chromosomes in Cenp-F-deficient cells frequently show a premature loss of chromatid cohesion. Thus, in addition to regulating kinetochore-microtubule interactions, Cenp-F might be required to protect centromeric cohesion prior to anaphase commitment. Intriguingly, whereas most of the sister-less kinetochores cluster near the spindle poles, some align at the spindle equator, possibly through merotelic or lateral orientations.

Background: Members of the Kinesin-3 family of kinesin-like proteins mediate transport of axonal vesicles (KIF1A, KIF1Bβ), distribution of mitochondria (KIF1Bα) and anterograde Golgi to ER vesicle transport (KIF1C). Until now, little is known about the regulation of kinesin-like proteins. Several proteins interact with members of this protein family. Here we report on a novel, K IF1 b inding p rotein (KBP) that was identified in yeast two-hybrid screens. Results: KBP was identified by using the yeast-two-hybrid system with an amino-terminal fragment of KIF1C as a bait that is strongly homologous to KIF1B. Here we investigated the interaction of KBP and KIF1B. The full length proteins coimmunoprecipitated after overexpression and in untransfected 293 cells. Immunofluorescence experiments revealed that KBP was mainly localized to mitochondria, as has been described for KIF1Bα. Overexpression of a deletion mutant or reduction of the KBP protein level using an anti-sense construct led to an aggregation of mitochondria. Such an effect is probably due to the lower activity of KIF1Bα in the absence of KBP, as was revealed in motility assays. Conclusion: KBP is a new binding partner for KIF1Bα that is a regulator of its transport function and thus represents a new type of kinesin interacting protein.

Kinesin‐1 drives the movement of diverse cargoes, and it has been proposed that specific kinesin light chain (KLC) isoforms target kinesin‐1 to these different structures. Here, we test this hypothesis using two in vitro motility assays, which reconstitute the movement of rough endoplasmic reticulum (RER) and vesicles present in a Golgi membrane fraction. We generated GST‐tagged fusion proteins of KLC1B and KLC1D that included the tetratricopeptide repeat domain and the variable C‐terminus. We find that preincubation of RER with KLC1B inhibits RER motility, whereas KLC1D does not. In contrast, Golgi fraction vesicle movement is inhibited by KLC1D but not KLC1B reagents. Both RER and vesicle movement is inhibited by preincubation with the GST‐tagged C‐terminal domain of ubiquitous kinesin heavy chain (uKHC), which binds to the N‐terminal domain of uKHC and alters its interaction with microtubules. We propose that although the TRR domains are required for cargo binding, it is the variable C‐terminal region of KLCs that are vital for targeting kinesin‐1 to different cellular structures.

Patient blood management (PBM) interventions aim to improve clinical outcomes by reducing bleeding and transfusion. We assessed whether existing evidence supports the routine use of combinations of these interventions during and after major surgery. Five systematic reviews and a National Institute of Health and Care Excellence health economic review of trials of common PBM interventions enrolling participants of any age undergoing surgery were updated. The last search was on June 1, 2019. Studies in trauma, burns, gastrointestinal haemorrhage, gynaecology, dentistry, or critical care were excluded. The co-primary outcomes were: risk of receiving red cell transfusion and 30-day or hospital all-cause mortality. Treatment effects were estimated using random-effects models and risk ratios (RR) with 95% confidence intervals (CIs). Heterogeneity assessments used I2. Network meta-analyses used a frequentist approach. The protocol was registered prospectively (PROSPERO CRD42018085730). Searches identified 393 eligible randomised controlled trials enrolling 54 917 participants. PBM interventions resulted in a reduction in exposure to red cell transfusion (RR=0.60; 95% CI 0.57, 0.63; I2=77%), but had no statistically significant treatment effect on 30-day or hospital mortality (RR=0.93; 95% CI 0.81, 1.07; I2=0%). Treatment effects were consistent across multiple secondary outcomes, sub-groups and sensitivity analyses that considered clinical setting, type of intervention, and trial quality. Network meta-analysis did not demonstrate additive benefits from the use of multiple interventions. No trial demonstrated that PBM was cost-effective. In randomised trials, PBM interventions do not have important clinical benefits beyond reducing bleeding and transfusion in people undergoing major surgery.