B cells represent a critical component of the adaptive immune response whose development and differentiation are determined by antigen-dependent and antigen-independent interactions. In this study, ...we explored the effects of IL-4 and pattern-recognition receptor (PRR) ligands on B cell development and differentiation by investigating their capacity to drive the in vitro maturation of human transitional B cells. In the presence of IL-4, ligands for TLR7/8, TLR9, and NOD1 were effective in driving the in vitro maturation of cord blood transitional B cells into mature, naïve B cells as measured by CD23 expression, ABCB1 transporter activation and upregulation of sIgM and sIgD. In addition, several stimulation conditions, including TLR9 ligand alone, favored an expansion of CD27.sup.+ IgM memory B cells. Transitional B cells stimulated with TLR7/8 ligand + IL-4 or TLR9 ligand, with or without IL-4, induced a significant subpopulation of CD23.sup.+ CD27.sup.+ B cells expressing high levels of sIgM and sIgD, a minor B cell subpopulation found in human peripheral blood. These studies illustrate the heterogeneity of the B cell populations induced by cytokine and PRR ligand stimulation. A comparison of transitional and mature, naïve B cells transcriptomes to identify novel genes involved in B cell maturation revealed that mature, naïve B cells were less transcriptionally active than transitional B cells. Nevertheless, a subset of differentially expressed genes in mature, naïve B cells was identified including genes associated with the IL-4 signaling pathway, PI3K signaling in B lymphocytes, the NF-kappaB signaling pathway, and the TNFR superfamily. When transitional B cells were stimulated in vitro with IL-4 and PRR ligands, gene expression was found to be dependent on the nature of the stimulants, suggesting that exposure to these stimulants may alter the developmental fate of transitional B cells. The influence of IL-4 and PRR signaling on transitional B cell maturation illustrates the potential synergy that may be achieved when certain PRR ligands are incorporated as adjuvants in vaccine formulations and presented to developing B cells in the context of an inflammatory cytokine environment. These studies demonstrate the potential of the PRR ligands to drive transitional B cell differentiation in the periphery during infection or vaccination independently of antigen mediated BCR signaling.
To identify a clinical fistula risk score following distal pancreatectomy.
Clinically relevant pancreatic fistula (CR-POPF) following distal pancreatectomy (DP) is a dominant contributor to ...procedural morbidity, yet risk factors attributable to CR-POPF and effective practices to reduce its occurrence remain elusive.
This multinational, retrospective study of 2026 DPs involved 52 surgeons at 10 institutions (2001-2016). CR-POPFs were defined by 2016 International Study Group criteria, and risk models generated using stepwise logistic regression analysis were evaluated by c-statistic. Mitigation strategies were assessed by regression modeling while controlling for identified risk factors and treating institution.
CR-POPF occurred following 306 (15.1%) DPs. Risk factors independently associated with CR-POPF included: age (<60 yrs: OR 1.42, 95% CI 1.05-1.82), obesity (OR 1.54, 95% CI 1.19-2.12), hypoalbuminenia (OR 1.63, 95% CI 1.06-2.51), the absence of epidural anesthesia (OR 1.59, 95% CI 1.17-2.16), neuroendocrine or nonmalignant pathology (OR 1.56, 95% CI 1.18-2.06), concomitant splenectomy (OR 1.99, 95% CI 1.25-3.17), and vascular resection (OR 2.29, 95% CI 1.25-3.17). After adjusting for inherent risk between cases by multivariable regression, the following were not independently associated with CR-POPF: method of transection, suture ligation of the pancreatic duct, staple size, the use of staple line reinforcement, tissue patches, biologic sealants, or prophylactic octreotide. Intraoperative drainage was associated with a greater fistula rate (OR 2.09, 95% CI 1.51-3.78) but reduced fistula severity (P < 0.001).
From this large analysis of pancreatic fistula following DP, CR-POPF occurrence cannot be reliably predicted. Opportunities for developing a risk score model are limited for performing risk-adjusted analyses of mitigation strategies and surgeon performance.
The COVID-19 pandemic response has shown how vaccine platform technologies can be used to rapidly and effectively counteract a novel emerging infectious disease. The speed of development for mRNA and ...vector-based vaccines outpaced those of subunit vaccines, however, subunit vaccines can offer advantages in terms of safety and stability. Here we describe a subunit vaccine platform technology, the molecular clamp, in application to four viruses from divergent taxonomic families: Middle Eastern respiratory syndrome coronavirus (MERS-CoV), Ebola virus (EBOV), Lassa virus (LASV) and Nipah virus (NiV). The clamp streamlines subunit antigen production by both stabilising the immunologically important prefusion epitopes of trimeric viral fusion proteins while enabling purification without target-specific reagents by acting as an affinity tag. Conformations for each viral antigen were confirmed by monoclonal antibody binding, size exclusion chromatography and electron microscopy. Notably, all four antigens tested remained stable over four weeks of incubation at 40°C. Of the four vaccines tested, a neutralising immune response was stimulated by clamp stabilised MERS-CoV spike, EBOV glycoprotein and NiV fusion protein. Only the clamp stabilised LASV glycoprotein precursor failed to elicit virus neutralising antibodies. MERS-CoV and EBOV vaccine candidates were both tested in animal models and found to provide protection against viral challenge.
Sensory hair bundles in the inner ear are composed of stereocilia that can be interconnected by a variety of different link types, including tip links, horizontal top connectors, shaft connectors, ...and ankle links. The ankle link antigen is an epitope specifically associated with ankle links and the calycal processes of photoreceptors in chicks. Mass spectrometry and immunoblotting were used to identify this antigen as the avian ortholog of the very large G-protein-coupled receptor VLGR1, the product of the Usher syndrome USH2C (Mass1) locus. Like ankle links, Vlgr1 is expressed transiently around the base of developing hair bundles in mice. Ankle links fail to form in the cochleae of mice carrying a targeted mutation in Vlgr1 (Vlgr1/del7TM), and the bundles become disorganized just after birth. FM1-43 N-(3-triethylammonium)propyl)-4-(4-(dibutylamino)styryl) pyridinium dibromide dye loading and whole-cell recordings indicate mechanotransduction is impaired in cochlear, but not vestibular, hair cells of early postnatal Vlgr1/del7TM mutant mice. Auditory brainstem recordings and distortion product measurements indicate that these mice are severely deaf by the third week of life. Hair cells from the basal half of the cochlea are lost in 2-month-old Vlgr1/del7TM mice, and retinal function is mildly abnormal in aged mutants. Our results indicate that Vlgr1 is required for formation of the ankle link complex and the normal development of cochlear hair bundles.
The aim of this study was to investigate the relationship between drain fluid amylase value on the first postoperative day (DFA1) and clinically relevant fistula (CR-POPF) after distal pancreatectomy ...(DP), and to identify the cut-off of DFA1 that optimizes CR-POPF prediction.
DFA1 is a well-recognized predictor of CR-POPF after pancreatoduodenectomy, but its role in DP is largely unexplored.
DFA1 levels were correlated with CR-POPF in 2 independent multi-institutional sets of DP patients: developmental (n = 338; years 2012 to 2017) and validation cohort (n = 166; years 2006 to 2016). Cut-off choice was based on Youden index calculation, and its ability to predict CR-POPF occurrence was tested in a multivariable regression model adjusted for clinical, demographic, operative, and pathological variables.
In the developmental set, median DFA1 was 1745 U/L and the CR-POPF rate was 21.9%. DFA1 correlated with CR-POPF with an area under the curve of 0.737 (P < 0.001). A DFA1 of 2000 U/L had the highest Youden index, with 74.3% sensitivity and 62.1% specificity. Patients in the validation cohort displayed different demographic and operative characteristics, lower values of DFA1 (784.5 U/L, P < 0.001), and reduced CR-POPF rate (10.2%, P < 0.001). However, a DFA1 of 2000 U/L had the highest Youden index in this cohort as well, with 64.7% sensitivity and 75.8% specificity. At multivariable analysis, DFA1 ≥2000 U/L was the only factor significantly associated with CR-POPF in both cohorts.
A DFA1 of 2000 U/L optimizes CR-POPF prediction after DP. These results provide the substrate to define best practices and improve outcomes for patients receiving DP.
The aim of this study was to identify the optimal fistula mitigation strategy following pancreaticoduodenectomy.
The utility of technical strategies to prevent clinically relevant postoperative ...pancreatic fistula (CR-POPF) following pancreatoduodenectomy (PD) may vary by the circumstances of the anastomosis. The Fistula Risk Score (FRS) identifies a distinct high-risk cohort (FRS 7 to 10) that demonstrates substantially worse clinical outcomes. The value of various fistula mitigation strategies in these particular high-stakes cases has not been previously explored.
This multinational study included 5323 PDs performed by 62 surgeons at 17 institutions. Mitigation strategies, including both technique related (ie, pancreatogastrostomy reconstruction; dunking; tissue patches) and the use of adjuvant strategies (ie, intraperitoneal drains; anastomotic stents; prophylactic octreotide; tissue sealants), were evaluated using multivariable regression analysis and propensity score matching.
A total of 522 (9.8%) PDs met high-risk FRS criteria, with an observed CR-POPF rate of 29.1%. Pancreatogastrostomy, prophylactic octreotide, and omission of externalized stents were each associated with an increased rate of CR-POPF (all P < 0.001). In a multivariable model accounting for patient, surgeon, and institutional characteristics, the use of external stents odds ratio (OR) 0.45, 95% confidence interval (95% CI) 0.25-0.81 and the omission of prophylactic octreotide (OR 0.49, 95% CI 0.30-0.78) were independently associated with decreased CR-POPF occurrence. In the propensity score matched cohort, an "optimal" mitigation strategy (ie, externalized stent and no prophylactic octreotide) was associated with a reduced rate of CR-POPF (13.2% vs 33.5%, P < 0.001).
The scenarios identified by the high-risk FRS zone represent challenging anastomoses associated with markedly elevated rates of fistula. Externalized stents and omission of prophylactic octreotide, in the setting of intraperitoneal drainage and pancreaticojejunostomy reconstruction, provides optimal outcomes.
The aim of this study was to elucidate the impact of intraoperative blood loss on outcomes following pancreatoduodenectomy (PD).
The negative impact of intraoperative blood loss on outcomes in PD has ...long been suspected but not well characterized, particularly those factors that may be within surgeons' control.
From 2001 to 2015, 5323 PDs were performed by 62 surgeons from 17 institutions. Estimated blood loss (EBL) was discretized (0 to 300, 301 to 750, 751 to 1300, and >1300 mL) using optimal scaling methodology. Multivariable regression, adjusted for patient, surgeon, and institutional variables, was used to identify associations between EBL and perioperative outcomes. Factors associated with both increased and decreased EBL were elucidated. The relative impact of surgeon-modifiable contributors was estimated through beta coefficient standardization.
The median EBL of the series was 400 mL interquartile range (IQR) 250 to 600. Intra-, post-, and perioperative transfusion rates were 15.8%, 24.8%, and 37.2%, respectively. Progressive EBL zones correlated with intra- but not postoperative transfusion in a dose-dependent fashion (P < 0.001), with a key threshold of 750 mL EBL (8.14% vs 40.9%; P < 0.001). Increasing blood loss significantly correlated with poor perioperative outcomes. Factors associated with increased EBL were trans-anastomotic stent placement, neoadjuvant chemotherapy, pancreaticogastrostomy reconstruction, multiorgan or vascular resection, and elevated operative time, of which 38.7% of the relative impact was "potentially modifiable" by the surgeon. Conversely, female sex, small duct, soft gland, minimally invasive approach, pylorus-preservation, biological sealant use, and institutional volume (≥67/year) were associated with decreased EBL, of which 13.6% was potentially under the surgeon's influence.
Minimizing blood loss contributes to fewer intraoperative transfusions and better perioperative outcomes for PD. Improvements might be achieved by targeting modifiable factors that influence EBL.
•Immunodeficient mice have a suppressed glial response after facial nerve axotomy.•Neuroprotective WT CD4+ T cells regulate the glial microenvironment.•Intrinsic motoneuron regeneration response is ...independent of immune status.•mSOD1 whole splenocytes induce cell death pathways after axotomy.•New role proposed for the immune system in neurodegenerative diseases.
When facial nerve axotomy (FNA) is performed on immunodeficient recombinase activating gene-2 knockout (RAG-2−/−) mice, there is greater facial motoneuron (FMN) death relative to wild type (WT) mice. Reconstituting RAG-2−/− mice with whole splenocytes rescues FMN survival after FNA, and CD4+ T cells specifically drive immune-mediated neuroprotection. Evidence suggests that immunodysregulation may contribute to motoneuron death in amyotrophic lateral sclerosis (ALS). Immunoreconstitution of RAG-2−/− mice with lymphocytes from the mutant superoxide dismutase (mSOD1) mouse model of ALS revealed that the mSOD1 whole splenocyte environment suppresses mSOD1 CD4+ T cell-mediated neuroprotection after FNA. The objective of the current study was to characterize the effect of CD4+ T cells on the central molecular response to FNA and then identify if mSOD1 whole splenocytes blocked these regulatory pathways.
Gene expression profiles of the axotomized facial motor nucleus were assessed from RAG-2−/− mice immunoreconstituted with either CD4+ T cells or whole splenocytes from WT or mSOD1 donors. The findings indicate that immunodeficient mice have suppressed glial activation after axotomy, and cell transfer of WT CD4+ T cells rescues microenvironment responses. Additionally, mSOD1 whole splenocyte recipients exhibit an increased astrocyte activation response to FNA. In RAG-2−/− + mSOD1 whole splenocyte mice, an elevation of motoneuron-specific Fas cell death pathways is also observed. Altogether, these findings suggest that mSOD1 whole splenocytes do not suppress mSOD1 CD4+ T cell regulation of the microenvironment, and instead, mSOD1 whole splenocytes may promote motoneuron death by either promoting a neurotoxic astrocyte phenotype or inducing Fas-mediated cell death pathways. This study demonstrates that peripheral immune status significantly affects central responses to nerve injury. Future studies will elucidate the mechanisms by which mSOD1 whole splenocytes promote cell death and if inhibiting this mechanism can preserve motoneuron survival in injury and disease.
Our objectives were to measure plasma concentrations of glucagon-like peptide 1 (GLP-1), glucose-dependent insulinotropic peptide (GIP), and peptide YY (PYY) in client-owned newly diagnosed diabetic ...cats and nondiabetic lean or overweight cats and to determine whether circulating concentrations of these hormones differed between study groups and if they increased postprandially as seen in other species. A total of 31 cats were recruited and placed into 1 of 3 study groups: lean (body condition score 4–5 on a scale of 1–9; n = 10), overweight (body condition score 6–8; n = 11), or diabetic (n = 10). Diabetics were newly diagnosed and had not had prior insulin therapy. Preprandial (fasting) and postprandial (60 min after meal) plasma hormone and glucose concentrations were measured at baseline and 2 and 4 wk. All cats were exclusively fed a commercially available high-protein and low-carbohydrate diet commonly prescribed to feline diabetic patients for 2 wk before the 2-wk assessment and continued through the 4-wk assessment. Results showed that plasma concentrations of GLP-1, GIP, PYY, and insulin increased in general after a meal in all study groups. Plasma PYY concentrations did not differ (P > 0.10) between study groups. Diabetics had greater plasma concentrations of GLP-1 and GIP compared with the other study groups at baseline (P < 0.05), and greater preprandial and postprandial GLP-1 concentrations than lean cats at 2 and 4 wk (P < 0.05). Preprandial plasma GIP concentrations were greater in diabetics than obese and lean (P < 0.05) cats at week 4. Postprandial plasma GIP concentrations in diabetics were greater than lean (P < 0.05) at week 2 and obese and lean cats (P < 0.05) at week 4. Together, our findings suggest that diabetic status is an important determinant of circulating concentrations of GLP-1 and GIP, but not PYY, in cats. The role of GLP-1, GIP, and PYY in the pathophysiology of feline obesity and diabetes remains to be determined.
•Diabetics had greater concentrations of GLP-1 and GIP than lean cats.•Diabetics had greater GIP concentrations than overweight cats.•GLP-1, GIP, and PYY increase postprandially in diabetic, lean and overweight cats.•Plasma PYY concentrations did not differ between study groups.•Diabetes is a determinant of GLP-1 and GIP, but not PYY concentrations, in cats.
Simulations of the neutron background for future large-scale particle dark matter detectors are presented. Neutrons were generated in rock and detector elements via spontaneous fission and (α,n) ...reactions, and by cosmic-ray muons. The simulation techniques and results are discussed in the context of the expected sensitivity of a generic liquid xenon dark matter detector. Methods of neutron background suppression are investigated. A sensitivity of 10−9–10−10 pb to WIMP-nucleon interactions can be achieved by a tonne-scale detector.
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