Different synaptotagmin isoforms (syt I, VII, and IX) sort to populations of dense-core vesicles with different sizes. These isoforms differ in their sensitivities to divalent cations and trigger different modes of exocytosis. Exocytosis triggered by these isoforms also differs in its sensitivity to inhibition by another isoform, syt IV.

IntroductionContemporary dogma has classically attributed hand dysfunction following hemodialysis arteriovenous fistula (AVF) placement to regional ischemia. We hypothesize that hemodynamic perturbations alone do not entirely explain the postoperative changes in hand function and, furthermore, that various elements of hand function are differentially affected following surgery.MethodsBilateral wrist and digital pressures and upper extremity nerve conduction tests were recorded preoperatively and at 6 weeks and 6 months following upper extremity AVF construction in 46 patients. Concurrently, biomechanical tests were administered to evaluate multiple limb functional domains, including grip strength, dexterity, sensation, and perception of hand function.ResultsMean participant age was 59 ± 14 years (75% male), and 48% were on hemodialysis at the time of access placement. Of the participants, 69% had a brachial-based AVF, and the remainder had radial-based accesses. Six weeks following AVF placement, a significant decrease in access-side digital pressures was observed, with only partial recovery at 6 months (P < 0.0001). Grip strength was significantly worse in the access-side limb (P = 0.0003), and the Disability of Arm, Shoulder and Hand (DASH) questionnaire score substantially worsened postoperatively (P = 0.06). Digital sensation and limb dexterity did not differ between limb sides (P > 0.1) or change significantly over time (P > 0.1). Principal component analyses demonstrated that nerve conduction parameters tended to track the biomechanical parameters, yet both were relatively independent of the hemodynamic parameters.DiscussionOur findings suggest that ischemia alone does not completely explain access-related hand dysfunction and that future study is needed to elucidate alternative mechanisms.

Background The neonatal innate immune system differs to microbial infection both quantitatively and qualitatively when compared to adults. Here, we provide the first genome-wide ex-vivo expression profile of umbilical cord blood (UCB) neutrophils from full-term infants prior to and in response to whole-blood LPS stimulation. Additionally, we provide cytokine expression prior to and following LPS stimulation. The genomic expression and cytokine profile are compared to LPS-stimulated whole blood from healthy adult subjects (HC). Methods Whole blood from UCB (n=6) and HC (n=6) was studied at baseline or was stimulated for 24 hours with 100 ngs/ml of lipopolysaccharide (LPS). CD66b+ neutrophils were subsequently isolated with microfluidic techniques and genome-wide expression analyses were performed. Ingenuity Pathway Analysis (IPA) software was utilized to predict downstream functional effects. Additionally, cytokine concentrations in whole blood prior to and after 24 hours of LPS incubation were determined. Results LPS stimulated whole blood from UCB demonstrated significant differences in both ex-vivo cytokine production and PMN gene expression. Mixed-effect modeling identified 1153 genes whose expression changed significantly in UCB and HC after exposure to LPS (p<0.001 with a minimum 1.5-fold change). IPA downstream predictions suggest that PMNs from UCB fail to effectively upregulate genes associated with activation, phagocytosis, and chemotaxis in response to LPS stimulation. Furthermore, whole blood from UCB showed increased IL-10 production to LPS, but failed to significantly increase several pro-inflammatory cytokines. Conclusions LPS-stimulated whole blood from UCB exhibited a markedly suppressed inflammatory cytokine production and PMN innate immune genome response. These differences in gene expression and cytokine production may be an adaptive response to a prior fetal environment, but may also explain their increased susceptibility to infections. Characterization of these deficits is the first step towards developing prophylactic and therapeutic interventions.

Background Despite being the definitive treatment for lower extremity peripheral arterial disease, vein bypass grafts fail in half of all cases. Early repair mechanisms following implantation, governed largely by the immune environment, contribute significantly to long-term outcomes. The current study investigates the early response patterns of circulating monocytes as a determinant of graft outcome. Methods and Results In 48 patients undergoing infrainguinal vein bypass grafting, the transcriptomes of circulating monocytes were analyzed pre-operatively and at 1, 7 and 28 days post-operation. Dynamic clustering algorithms identified 50 independent gene response patterns. Three clusters (64 genes) were differentially expressed, with a hyperacute response pattern defining those patients with failed versus patent grafts twelve months post-operation. A second independent data set, comprised of 96 patients subjected to major trauma, confirmed the value of these 64 genes in predicting an uncomplicated versus complicated recovery. Causal network analysis identified eight upstream elements that regulate these mediator genes, and Bayesian analysis with a priori knowledge of the biological interactions were integrated to create a functional network describing the relationships among the regulatory elements and downstream mediator genes. Linear models predicted the removal of either Signal Transducer and Activator of Transcription 3 (STAT3) or Myeloid Differentiation Primary Response gene 88 (MYD88) to shift mediator gene expression levels towards those seen in successful grafts. Conclusions A novel combination of dynamic gene clustering, linear models and Bayesian network analysis has identified a core set of regulatory genes whose manipulations could migrate vein grafts towards a more favorable remodeling phenotype.