Citations

Previous studies have indicated that the G-protein-coupled secretin receptor is present as a homodimer, organized through symmetrical contacts in transmembrane domain IV, and that receptor dimerization is critical for high-potency signalling by secretin. However, whether all of the receptor exists in the dimeric form or if this is regulated is unclear. We used measures of quantal brightness of the secretin receptor tagged with monomeric enhanced green fluorescent protein (mEGFP) and spatial intensity distribution analysis to assess this. Calibration using cells expressing plasma membrane-anchored forms of mEGFP initially allowed us to demonstrate that the epidermal growth factor receptor is predominantly monomeric in the absence of ligand and while wild-type receptor was rapidly converted into a dimeric form by ligand, a mutated form of this receptor remained monomeric. Equivalent studies showed that, at moderate expression levels, the secretin receptor exists as a mixture of monomeric and dimeric forms, with little evidence of higher-order complexity. However, sodium butyrate-induced up-regulation of the receptor resulted in a shift from monomeric towards oligomeric organization. In contrast, a form of the secretin receptor containing a pair of mutations on the lipid-facing side of transmembrane domain IV was almost entirely monomeric. Down-regulation of the secretin receptor-interacting G-protein Gαs did not alter receptor organization, indicating that dimerization is defined specifically by direct protein–protein interactions between copies of the receptor polypeptide, while short-term treatment with secretin had no effect on organization of the wild-type receptor but increased the dimeric proportion of the mutated receptor variant.

ObjectivesCurrently, there are no cardiovascular (CV) preprocedure screening parameters for patients undergoing in‐office laryngeal procedures (IOLP). Studies have shown significant changes in CV measures for IOLP. The aim was to develop and evaluate a pre‐IOLP CV screening protocol.MethodsReview of IOLP literature and consultation with an anesthesiologist and cardiologist led to the development of CV parameters and questions related to four metabolic equivalents (METS) of work as a patient‐screening tool before IOLP. A separate cohort was screened with only a modified CV protocol. All patients were screened for heart rate (HR) and blood pressure (BP) elevation prior to the procedure. Need for further CV evaluation was characterized as systolic blood pressure BP >160, diastolic BP >100, and/or HR >110 beats/minute. Patients whose BP/HR exceeded these values were referred to their primary care physician (PCP) before re‐screening. If parameters were exceeded again at the second screen, then the procedure was done under monitored anesthesia care.ResultsThe first study phase included 56 patients. The fail rate was 40% largely related to four METS of work. The second study phase included 440 patients. The screen fail rate was 15 patients of 572 (2.6%). Of these, 12 patients of 132 (9.1%) failed the initial screen and were sent to their PCP for further evaluation, and five of 440 (1.4%) patients failed on the day of the procedure. Overall, five of 440 (1.5%) patients would qualify to have their site of service changed for their laryngology procedure from an unmonitored to a monitored setting due to the prescreening criteria.ConclusionFew patients needed further workup based upon the in‐office CV parameters set in this study. Patients with CV risk factors were identified by the screening protocol. Having established hemodynamic parameters in place may improve the safety of IOLP with a very low physician burden.Level of Evidence2b Laryngoscope, 127:1845–1849, 2017

Objectives: To evaluate whether a quality improvement intervention reduces sternal wound infection rates in children after cardiac surgery. Design: This is a pre- and postintervention quality improvement study. Setting: A 16-bed cardiac ICU in a university-affiliated pediatric tertiary care children’s hospital. Patients: All patients undergoing cardiac surgery via median sternotomy from January 2010 to December 2014 are included. The sternal wound infection rates for primary closure and delayed sternal closure are reported per 100 sternotomies. The hospital-acquired infection records were used to identify preintervention cases, while postintervention cases were collected prospectively. Intervention: Implementation of a sternal wound prevention bundle during the preoperative, intraoperative, and postoperative periods for cardiac surgical cases. Measurements and Main Results: During the preintervention period, 32 patients (3.8%) developed sternal wound infection, whereas only 19 (2.1%) developed sternal wound infection during the postintervention period (p = 0.04). The rates of sternal wound infection following primary closure were not significantly different pre- and postintervention (2.4% vs 1.6%; p = 0.35). However, patients with delayed sternal closure had significantly lower postintervention infection rates (10.6% vs 3.9%; p = 0.02). Conclusions: Implementation of a sternal wound prevention bundle during the perioperative period was associated with lower sternal wound infection rates in surgeries with delayed sternal closure.

AbstractImmunoglobulin light chain (AL) amyloidosis is a fatal complication of B‐cell proliferation secondary to deposition of amyloid fibrils in various organs. Urinary exosomes (UEX) are the smallest of the microvesicles excreted in the urine. Previously, we found UEX of patients with AL amyloidosis contained immunoglobulin light chain (LC) oligomers that patients with multiple myeloma did not have. To further explore the role of the LC oligomers, UEX was isolated from an AL amyloidosis patient with progressive renal disease despite achieving a complete response. LC oligomers were identified. Mass spectrometry (MS) of the UEX and serum identified two monoclonal lambda LCs. Proteomics of the trypsin digested amyloid fragments in the kidney by laser microdissection and MS analysis identified a λ6 LC. The cDNA from plasma cell clone was from the IGLV‐ 6‐57 family and it matched the amino acid sequences of the amyloid peptides. The predicted mass of the peptide product of the cDNA matched the mass of one of the two LCs identified in the UEX and serum. UEX combined with MS were able to identify 2 monoclonal lambda LCs that current clinical methods could not. It also identified the amyloidogenic LC which holds potential for response assessment in the future.

Gut dysbiosis, host genetics, and environmental triggers are implicated as causative factors in inflammatory bowel disease (IBD), yet mechanistic insights are lacking. Longitudinal analysis of ulcerative colitis (UC) patients following total colectomy with ileal anal anastomosis (IPAA) where >50% develop pouchitis offers a unique setting to examine cause vs. effect. To recapitulate human IPAA, we employed a mouse model of surgically created blind self-filling (SFL) and self-emptying (SEL) ileal loops using wild-type (WT), IL-10 knockout (KO) (IL-10), TLR4 KO (T4), and IL-10/T4 double KO mice. After 5 wk, loop histology, host gene/protein expression, and bacterial 16s rRNA profiles were examined. SFL exhibit fecal stasis due to directional motility oriented toward the loop end, whereas SEL remain empty. In WT mice, SFL, but not SEL, develop pouchlike microbial communities without accompanying active inflammation. However, in genetically susceptible IL-10-deficient mice, SFL, but not SEL, exhibit severe inflammation and mucosal transcriptomes resembling human pouchitis. The inflammation associated with IL-10 required TLR4, as animals lacking both pathways displayed little disease. Furthermore, germ-free IL-10 mice conventionalized with SFL, but not SEL, microbiota populations develop severe colitis. These data support essential roles of stasis-induced, colon-like microbiota, TLR4-mediated colonic metaplasia, and genetic susceptibility in the development of pouchitis and possibly UC. However, these factors by themselves are not sufficient. Similarities between this model and human UC/pouchitis provide opportunities for gaining insights into the mechanistic basis of IBD and for identification of targets for novel preventative and therapeutic interventions.

Developing a systematic approach to hospital discharges can lead to improvements and serve a model for other inpatient wards.

ObjectiveThe long‐term outcome of patients with nonradiographic axial spondyloarthritis (SpA) is unclear, particularly whether few or most progress to ankylosing spondylitis (AS). Our objective was to examine the progression to AS in a population‐based inception cohort of patients with nonradiographic axial SpA.MethodsThe Rochester Epidemiology Project (REP) is a longstanding population‐based study of health in the residents of Olmsted County, Minnesota. We searched the REP from 1985 to 2010 using diagnostic and procedural codes for back pain, HLA–B27, and magnetic resonance imaging of the pelvis, and we performed detailed chart reviews to identify subjects who fulfilled the Assessment of SpondyloArthritis international Society classification criteria for axial SpA but did not have AS. We followed these subjects from disease onset to March 15, 2015, and used survival analysis to measure the time to progression to AS.ResultsAfter screening 2,151 patients, we identified 83 subjects with new‐onset nonradiographic axial SpA. Over a mean follow‐up of 10.6 years, progression to AS occurred in 16 patients. The probability that the condition would remain as nonradiographic axial SpA at 5, 10, and 15 years was 93.6%, 82.7%, and 73.6%, respectively. There was more frequent and more rapid progression among subjects in the imaging arm (n = 18) than among those in the clinical arm (n = 65) (28% versus 17%; hazard ratio 3.50 [95% confidence interval 1.15–10.6], P = 0.02).ConclusionProgression to AS occurred in a minority (26%) of patients with nonradiographic axial SpA over as long as 15 years of follow‐up. This suggests that the classification criteria for nonradiographic axial SpA identifies many patients in whom the condition is unlikely to progress to AS or that nonradiographic axial SpA represents a prolonged prodromal state that takes longer to evolve to AS and thus requires longer follow‐up.

Aberrant intracellular calcium levels and increased cAMP signaling contribute to the development of polycystic kidney disease (PKD). cAMP can be hydrolyzed by various phosphodiesterases (PDEs). To examine the role of cAMP hydrolysis and the most relevant PDEs in the pathogenesis of PKD, we examined cyst development in Pde1 - or Pde3 -knockout mice on the Pkd2 −/WS25 background (WS25 is an unstable Pkd2 allele). These PDEs were selected because of their importance in cross-talk between calcium and cyclic nucleotide signaling ( PDE1 ), control of cell proliferation and cystic fibrosis transmembrane conductance regulator (CFTR) –driven fluid secretion (PDE3), and response to vasopressin V2 receptor activation (both). In Pkd2 −/WS25 mice, knockout of Pde1a , Pde1c , or Pde3a but not of Pde1b or Pde3b aggravated the development of PKD and was associated with higher levels of protein kinase A–phosphorylated (Ser133) cAMP–responsive binding protein (P-CREB), activating transcription factor-1, and CREB–induced CRE modulator proteins in kidney nuclear preparations. Immunostaining also revealed higher expression of P-CREB in Pkd2−/ WS25 ; Pde1a −/− , Pkd2− /WS25 ; Pde1c −/− , and Pkd2−/ WS25 ; Pde3a −/− kidneys. The cystogenic effect of desmopressin administration was markedly enhanced in Pkd2 −/WS25 ; Pde3a −/− mice, despite PDE3 accounting for only a small fraction of renal cAMP PDE activity. These observations show that calcium- and calmodulin-dependent PDEs ( PDE1A and PDE1C ) and PDE3A modulate the development of PKD, possibly through the regulation of compartmentalized cAMP pools that control cell proliferation and CFTR–driven fluid secretion. Treatments capable of increasing the expression or activity of these PDEs may, therefore, retard the development of PKD.