Uptake efficiency of surface modified gold nanoparticles does not correlate with functional changes and cytokine secretion in human dendritic cells in vitro.

Engineering nanoparticles (NPs) for immune modulation require a thorough understanding of their interaction(s) with cells. Gold NPs (AuNPs) were coated with polyethylene glycol (PEG), polyvinyl alcohol (PVA) or a mixture of both with either positive or negative surface charge to investigate uptake and cell response in monocyte-derived dendritic cells (MDDCs). Inductively coupled plasma optical emission spectrometry and transmission electron microscopy were used to confirm the presence of Au inside MDDCs. Cell viability, (pro-)inflammatory responses, MDDC phenotype, activation markers, antigen uptake and processing were analyzed. Cell death was only observed for PVA-NH2 AuNPs at the highest concentration. MDDCs internalize AuNPs, however, surface modification influenced uptake. Though limited uptake was observed for PEG-COOH AuNPs, a significant tumor necrosis factor-alpha release was induced. In contrast, (PEG+PVA)-NH2 and PVA-NH2 AuNPs were internalized to a higher extent and caused interleukin-1beta secretion. None of the AuNPs caused changes in MDDC phenotype, activation or immunological properties.

Alteration of ZnT5-mediated zinc import into the early secretory pathway affects the secretion of growth hormone from rat pituitary cells

BACKGROUND Aggregation of growth hormone (GH) required for its proper storage in granules is facilitated by zinc (Zn(2+)) transported by specific zinc transporters in and out of the regulated secretory pathway. Slc30a5 (ZnT5) was reported to have the highest gene expression among all zinc transporters in primary mouse pituitary cells while ZnT5-null mice presented with abnormal bone development and impaired growth compared to wild-type counterparts. METHODS In vitro studies performed in GH3 cells, a rat pituitary cell line that endogenously produces rat GH (rGH), included analysis of: cytoplasmic Zn(2+) pool changes after altering rSlc30a5 expression (luciferase assay), rZnT5 association with different compartments of the regulated secretory pathway (confocal microscopy), and the rGH secretion after rSlc30a5 knock-down (Western blot). RESULTS Confocal microscopy demonstrated high co-localization of rZnT5 with ER and Golgi (early secretory pathway) while siRNA-mediated knock-down of rSlc30a5 gene expression led to a significant reduction in rGH secretion. Furthermore, altered expression of rSlc30a5 (knock-down/overexpression) evoked changes in the cytoplasmic Zn(2+) pool indicating its important role in mediating Zn(2+) influx into intracellular compartments of the regulated secretory pathway. CONCLUSION Taken together, these results suggest that ZnT5 might play an important role in regulated GH secretion that is much greater than previously anticipated.

Impact of proton pump inhibitor use on magnesium homoeostasis: a cross-sectional study in a tertiary emergency department.

BACKGROUND To date, the use of proton pump inhibitors (PPIs) has been associated with a low risk of hypomagnesaemia and associated adverse outcomes. We hypothesised that a better risk estimate could be derived from a large cohort of outpatients admitted to a tertiary emergency department (ED). METHODS A cross-sectional study was performed in 5118 patients who had measurements of serum magnesium taken on admission to a large tertiary care ED between January 2009 and December 2010. Hypomagnesaemia was defined as a serum magnesium concentration < 0.75 mmol/l. Demographical data, serum electrolyte values, data on medication, comorbidities and outcome with regard to length of hospital stay and mortality were analysed. RESULTS Serum magnesium was normally distributed where upon 1246 patients (24%) were hypomagnesaemic. These patients had a higher prevalence of out-of-hospital PPI use and diuretic use when compared with patients with magnesium levels > 0.75 mmol/l (both p < 0.0001). In multivariable regression analyses adjusted for PPIs, diuretics, renal function and the Charlson comorbidity index score, the association between use of PPIs and risk for hypomagnesaemia remained significant (OR = 2.1; 95% CI: 1.54-2.85). While mortality was not directly related to low magnesium levels (p = 0.67), the length of hospitalisation was prolonged in these patients even after adjustment for underlying comorbid conditions (p < 0.0001). CONCLUSION Use of PPIs predisposes patients to hypomagnesaemia and such to prolonged hospitalisation irrespective of the underlying morbidity, posing a critical concern.

Eosinophilic oesophagitis and proton pump inhibitor-responsive oesophageal eosinophilia have similar clinical, endoscopic and histological findings.

BACKGROUND Some patients with a phenotypic appearance of eosinophilic oesophagitis (EoE) respond histologically to PPI, and are described as having PPI-responsive oesophageal eosinophilia (PPI-REE). It is unclear if PPI-REE is a GERD-related phenomenon, a subtype of EoE, or a completely unique entity. AIM To compare demographic, clinical and histological features of EoE and PPI-REE. METHODS Two databases were reviewed from the Walter Reed and Swiss EoE databases. Patients were stratified into two groups, EoE and PPI-REE, based on recent EoE consensus guidelines. Response to PPI was defined as achieving less than 15 eos/hpf and a 50% decrease from baseline following at least a 6-week course of treatment. RESULTS One hundred and three patients were identified (63 EoE and 40 PPI-REE; mean age 40.2 years, 75% male and 89% Caucasian). The two cohorts had similar dysphagia (97% vs. 100%, P = 0.520), food impaction (43% vs. 35%, P = 0.536), and heartburn (33% vs. 32%, P = 1.000) and a similar duration of symptoms (6.0 years vs. 5.8 years, P = 0.850). Endoscopic features were also similar between EoE and PPI-REE; rings (68% vs. 68%, P = 1.000), furrows (70% vs. 70%, P = 1.000), plaques (19% vs. 10%, P = 0.272), strictures (49% vs. 30%, P = 0.066). EoE and PPI-REE were similar in the number of proximal (39 eos/hpf vs. 38 eos/hpf, P = 0.919) and distal eosinophils (50 vs. 43 eos/hpf, P = 0.285). CONCLUSIONS EoE and PPI-responsive oesophageal eosinophilia are similar in clinical, histological and endoscopic features and therefore are indistinguishable without a PPI trial. Further studies are needed to determine why a subset of patients with oesophageal eosinophilia respond to PPI.

Crystal structure of the sodium-proton antiporter NhaA dimer and new mechanistic insights

Sodium-proton antiporters rapidly exchange protons and sodium ions across the membrane to regulate intracellular pH, cell volume, and sodium concentration. How ion binding and release is coupled to the conformational changes associated with transport is not clear. Here, we report a crystal form of the prototypical sodium-proton antiporter NhaA from Escherichia coli in which the protein is seen as a dimer. In this new structure, we observe a salt bridge between an essential aspartic acid (Asp163) and a conserved lysine (Lys300). An equivalent salt bridge is present in the homologous transporter NapA, but not in the only other known crystal structure of NhaA, which provides the foundation of most existing structural models of electrogenic sodium-proton antiport. Molecular dynamics simulations show that the stability of the salt bridge is weakened by sodium ions binding to Asp164 and the neighboring Asp163. This suggests that the transport mechanism involves Asp163 switching between forming a salt bridge with Lys300 and interacting with the sodium ion. pKa calculations suggest that Asp163 is highly unlikely to be protonated when involved in the salt bridge. As it has been previously suggested that Asp163 is one of the two residues through which proton transport occurs, these results have clear implications to the current mechanistic models of sodium-proton antiport in NhaA.

Association Between Baseline Impedance Values and Response Proton Pump Inhibitorsin Patients With Heartburn

BACKGROUND & AIMS: Esophageal impedance measurements have been proposed to indicate the status of the esophageal mucosa, and might be used to study the roles of the impaired mucosal integrity and increased acid sensitivity in patients with heartburn. We compared baseline impedance levels among patients with heartburn who did and did not respond to proton pump inhibitor (PPI) therapy, along with the pathophysiological characteristics of functional heartburn (FH). METHODS: In a case-control study, we collected data from January to December 203 on patients with heartburn and normal findings from endoscopy who were not receiving PPI therapy and underwent impedance pH testing at hospitals in Italy. Patients with negative test results were placed on an 8-week course of PPI therapy (84 patients received esomeprazole and 36 patients received pantoprazole). Patients with more than 50% symptom improvement were classified as FH/PPI responders and patients with less than 50% symptom improvement were classified as FH/PPI nonresponders. Patients with hypersensitive esophagus and healthy volunteers served as controls. In all patients and controls, we measured acid exposure time, number of refluxes, baseline impedance, and swallow-induced peristaltic wave indices. RESULTS: FH/PPI responders had higher acid exposure times, numbers of reflux events, and acid refluxes compared with FH/PPI nonresponders (P < .05). Patients with hypersensitive esophagus had mean acid exposure times and numbers of reflux events similar to those of FH/PPI responders. Baseline impedance levels were lower in FH/PPI responders and patients with hypersensitive esophagus, compared with FH/PPI nonresponders and healthy volunteers (P < .001). Swallow-induced peristaltic wave indices were similar between FH/PPI responders and patients with hypersensitive esophagus. CONCLUSIONS: Patients with FH who respond to PPI therapy have impedance pH features similar to those of patients with hypersensitive esophagus. Baseline impedance measurements might allow for identification of patients who respond to PPIs but would be classified as having FH based on conventional impedance-pH measurements.

Stress-induced cortisol secretion impairs detection performance in x-ray baggage screening for hidden weapons by screening novices

Aviation security strongly depends on screeners' performance in the detection of threat objects in x-ray images of passenger bags. We examined for the first time the effects of stress and stress-induced cortisol increases on detection performance of hidden weapons in an x-ray baggage screening task. We randomly assigned 48 participants either to a stress or a nonstress group. The stress group was exposed to a standardized psychosocial stress test (TSST). Before and after stress/nonstress, participants had to detect threat objects in a computer-based object recognition test (X-ray ORT). We repeatedly measured salivary cortisol and X-ray ORT performance before and after stress/nonstress. Cortisol increases in reaction to psychosocial stress induction but not to nonstress independently impaired x-ray detection performance. Our results suggest that stress-induced cortisol increases at peak reactivity impair x-ray screening performance.

The Salmonella pathogenicity island (SPI)-2 and SPI-1 type III secretion systems allow Salmonella serovar typhimurium to trigger colitis via MyD88-dependent and MyD88-independent mechanisms.

Salmonella typhimurium can colonize the gut, invade intestinal tissues, and cause enterocolitis. In vitro studies suggest different mechanisms leading to mucosal inflammation, including 1) direct modulation of proinflammatory signaling by bacterial type III effector proteins and 2) disruption or penetration of the intestinal epithelium so that penetrating bacteria or bacterial products can trigger innate immunity (i.e., TLR signaling). We studied these mechanisms in vivo using streptomycin-pretreated wild-type and knockout mice including MyD88(-/-) animals lacking an adaptor molecule required for signaling via most TLRs. The Salmonella SPI-1 and the SPI-2 type III secretion systems (TTSS) contributed to inflammation. Mutants that retain only a functional SPI-1 (M556; sseD::aphT) or a SPI-2 TTSS (SB161; DeltainvG) caused attenuated colitis, which reflected distinct aspects of the colitis caused by wild-type S. typhimurium: M556 caused diffuse cecal inflammation that did not require MyD88 signaling. In contrast, SB161 induced focal mucosal inflammation requiring MyD88. M556 but not SB161 was found in intestinal epithelial cells. In the lamina propria, M556 and SB161 appeared to reside in different leukocyte cell populations as indicated by differential CD11c staining. Only the SPI-2-dependent inflammatory pathway required aroA-dependent intracellular growth. Thus, S. typhimurium can use two independent mechanisms to elicit colitis in vivo: SPI-1-dependent and MyD88-independent signaling to epithelial cells and SPI-2-dependent intracellular proliferation in the lamina propria triggering MyD88-dependent innate immune responses.

InvB is required for type III-dependent secretion of SopA in Salmonella enterica serovar Typhimurium.

The Salmonella effector protein SopA is translocated into host cells via the SPI-1 type III secretion system (TTSS) and contributes to enteric disease. We found that the chaperone InvB binds to SopA and slightly stabilizes it in the bacterial cytosol and that it is required for its transport via the SPI-1 TTSS.

Measurement of long-range pseudorapidity correlations and azimuthal harmonics in √s_NN=5.02 TeV proton-lead collisions with the ATLAS detector

Measurements of two-particle correlation functions and the first five azimuthal harmonics, v 1 to v 5 , are presented, using 28 nb −1 of p+Pb collisions at a nucleon-nucleon center-of-mass energy of √s NN=5.02 TeV measured with the ATLAS detector at the LHC. Significant long-range “ridgelike” correlations are observed for pairs with small relative azimuthal angle (|Δϕ|<π/3 ) and back-to-back pairs (|Δϕ|>2π/3 ) over the transverse momentum range 0.4

4 GeV. The v 2 (p T ) , v 3 (p T ) , and v 4 (p T ) are compared to the v n coefficients in Pb+Pb collisions at √s NN=2.76 TeV with similar event multiplicities. Reasonable agreement is observed after accounting for the difference in the average p T of particles produced in the two collision systems.