The intraperitoneal bacteriology and antimicrobial resistance in acute appendicitis among children: a retrospective cohort study between the years 2007-2017.

This study aims to describe the microbiology and susceptibility profile of the intraperitoneal flora in complicated appendicitis. It is a retrospective cohort study including children < 18-year-old with pathologically confirmed appendicitis, from 2007 to 2017. It included 1466 children. Intraperitoneal samples were obtained from 655 (44.7%) patients, and 201 (30.7%) had positive culture with 395 pathogens. Gram-negative rods comprised 67.6%, Gram-positive cocci 21.5%, and anaerobes 10.9% of the isolates. Gram-positive cocci were detected in 67 (37.8%) patients. Milleri group Streptococci was the most frequently isolated Gram-positive (44.7%). The proportional rate of Milleri group Streptococci from Gram-positive cocci increased from 9.5 to 56.3% (P < 0.001, OR 12.214). Patients with Gram-positive cocci had longer hospital stay (mean 9.36 + 6.385 vs 7.72 + 4.582, P = 0.036, (CI -3.165, -0.105)) and more complicated disease (89.5% vs 78.4%, P = 0.045, OR 2.342). Patients with Milleri group Streptococci isolates readmitted more frequently (26.5% vs 13.2%, P = 0.05, OR 2.37). Resistance to amoxicillin-clavulanate, gentamicin, ceftazidime, piperacillin-tazobactam, and amikacin were detected in 29.1%, 6.5%, 2.3%, 1.2%, and 0.7% of the Gram-negative rods, respectively.Conclusion: The rates of Gram-positive cocci and particularly Milleri group Streptococci in peritoneal fluid are increasing. More complicated disease and longer hospital stay in Gram-positive cocci and higher readmission rate in Milleri group Streptococci. These emphasize the role of anti-Gram-positive antimicrobials. What is known: • Gram-negative rods are the main isolates in complicated appendicitis. • The choice of antibiotic regimen is an unsettled issue due to resistance. What is new: • Increased rate of Gram-positive cocci and Milleri group Streptococci. • More complicated disease, longer hospital stay, and higher readmission rate.

A privacy preserving protocol for tracking participants in phase I clinical trials.

OBJECTIVE: Some phase 1 clinical trials offer strong financial incentives for healthy individuals to participate in their studies. There is evidence that some individuals enroll in multiple trials concurrently. This creates safety risks and introduces data quality problems into the trials. Our objective was to construct a privacy preserving protocol to track phase 1 participants to detect concurrent enrollment. DESIGN: A protocol using secure probabilistic querying against a database of trial participants that allows for screening during telephone interviews and on-site enrollment was developed. The match variables consisted of demographic information. MEASUREMENT: The accuracy (sensitivity, precision, and negative predictive value) of the matching and its computational performance in seconds were measured under simulated environments. Accuracy was also compared to non-secure matching methods. RESULTS: The protocol performance scales linearly with the database size. At the largest database size of 20,000 participants, a query takes under 20s on a 64 cores machine. Sensitivity, precision, and negative predictive value of the queries were consistently at or above 0.9, and were very similar to non-secure versions of the protocol. CONCLUSION: The protocol provides a reasonable solution to the concurrent enrollment problems in phase 1 clinical trials, and is able to ensure that personal information about participants is kept secure.

Receptor and subunit specific interactions of RIC-3 with nicotinic acetylcholine receptors.

RIC-3 belongs to a conserved family of proteins influencing maturation of nicotinic acetylcholine receptors (nAChRs). RIC-3 homologues were shown to differently affect different nAChRs. Here we show that coexpression with RIC-3 increases the level of surface expression of DEG-3 while slightly reducing the level of surface expression of DES-2, both subunits of the DEG-3/DES-2 nAChRs. Those different effects are a likely explanation for the previously demonstrated effects of RIC-3, an endoplasmic reticulum resident protein, on properties of this receptor. To understand how RIC-3 interacts with different nAChR subunits, we identified and characterized domains and residues enabling this interaction. This analysis shows that conserved residues in the second RIC-3 transmembrane domain are needed for its interactions with two different Caenorhabditis elegans nAChRs, DEG-3/DES-2 and ACR-16. These conserved residues do not, however, function alone; rather, we show that additional domains also enable RIC-3's interactions with these receptors. Interestingly, the relative importance of these residues or of other domains mediating interactions of RIC-3 with nAChRs differs for the two different receptors. Differences in the way that RIC-3, predicted to be an intrinsically disordered protein, interacts with different receptors and receptor subunits suggest that it may adopt different conformations to enable these interactions. Such differences may explain both the effects of RIC-3 on receptor properties and the differences in its effects on different receptors.

RIC-3 affects properties and quantity of nicotinic acetylcholine receptors via a mechanism that does not require the coiled-coil domains.

Members of the RIC-3 gene family are effectors of nicotinic acetylcholine receptor (nAChR) expression in vertebrates and invertebrates. In Caenorhabditis elegans RIC-3 is needed for functional expression of multiple nAChRs, including the DEG-3/DES-2 nAChR. Effects of RIC-3 on DEG-3/DES-2 functional expression are found in vivo and following heterologous expression in Xenopus leavis oocytes. We now show that in X. leavis oocytes RIC-3 also affects the kinetics and agonist affinity properties of the DEG-3/DES-2 receptor. Because these effects are mimicked by increasing the ratio of DEG-3 subunits within DEG-3/DES-2 receptors, this suggests that RIC-3 may preferentially promote maturation of DEG-3-rich receptors. Indeed, effects of RIC-3 on functional expression of DEG-3/DES-2 positively correlate with the DEG-3 to DES-2 ratio. All RIC-3 family members have two transmembrane domains followed by one or two coiled-coil domains. Here we show that the effects of RIC-3 on functional expression and on receptor properties are mediated by the transmembrane domains and do not require the coiled-coil domains. In agreement with this, mammals express a RIC-3 transcript lacking the coiled-coil domain that is capable of promoting DEG-3/DES-2 functional expression. Last, we show that RIC-3 affects DEG-3 quantity, suggesting stabilization of receptors or receptor intermediates by RIC-3. Together our results suggest that subunit-specific interactions of RIC-3 with nAChR subunits, mediated by the transmembrane domains, are sufficient for the effects of RIC-3 on nAChR quantity and quality.