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During antigen recognition by T cells different receptors and ligands form a pattern in the intercellular junction called the immunological synapse, which might be involved in T-cell activation. Recently, a synapse assembly model has been proposed, which enables the calculation of the propensity for synapse assembly driven by membrane-constrained protein binding interactions. We bring together model predictions of mature synapse assembly with data on the dependence of T-cell responses on T-cell receptor (TCR)–MHC–peptide (pMHC) binding kinetics. Predictions of mature synapse assembly, based on TCR–pMHC binding kinetics, correlate well with observed cytokine responses by T cells bearing the relevant TCR but not with cytotoxic T lymphocyte-mediated killing. We discuss the suggested different role for the synapse in pre- and post-nuclear activation events in T cells. The view of immunological synapse assembly given here emphasizes the importance of both the on and off rates for the TCR–pMHC interaction and in this context recent data on a positive role for analogs of self-peptides in synapse assembly is considered. [ABSTRACT FROM AUTHOR]

A framework for quantitative analysis of the mechanisms underlying immunological synapse assembly has been recently developed. This model uses partial differential equations to describe the binding interactions of receptors and ligands, with the constraint that they are embedded in apposed deformable membranes linked to a cytoskeletal complex. [ABSTRACT FROM AUTHOR]

Shigellosis cases have decreased gradually in Japan in recent years, but indigenous shigellosis outbreaks sometimes occur in childcare facilities. From national surveillance data, we identified a shigellosis outbreak involving a kindergarten. After detecting Shigella sonnei in Kitakyushu City, we conducted active case finding and epidemiological investigation in Kindergarten Z, including stool specimen collection and interviews. The stool specimens were cultured, and isolated strains were subjected to pulsed-field gel electrophoresis (PFGE) and multiple-locus variable-number tandem-repeat analysis (MLVA). Between September 1 and December 31, 2014, we identified 19 cases: 14 confirmed, 2 suspected, and 3 asymptomatic. Of the 19 cases, 16 were epidemiologically associated with Kindergarten Z (10 pupils, 5 family members, and 1 teacher). On October 19, a pupil with gastrointestinal illness participated in the kindergarten's sports festival, in which the pupils were split into "red" and "white" teams; the pupil in question belonged to the red team. Attack rates of the red and white teams were 8% (7/82) and 0% (0/108), respectively (relative risk, 10.5; 95% confidence interval, 1.3–82.1). PFGE patterns were identical or similar for the isolates in all 17 cases; 7 isolates were identical, and the others had one locus difference on MLVA. We concluded that contact during the sports festival could have been responsible for spread of the shigellosis outbreak at the kindergarten, although the infection source was not determined. It is vital to inform guardians immediately after detection of shigellosis cases that symptomatic pupils should not participate in activities such as sports festivals. [ABSTRACT FROM AUTHOR]

The optical rotation and fluorescence anisotropy for gellan aqueous systems were measured at pH 4, 7, and 10 to elucidate the effect of pH on the conformation of gellan chains. The optical rotation study suggests that pH affects the conformation of helical gellan chains and their aggregation behavior but the coil–helix transition temperature. By comparing the chain mobility estimated from the fluorescence anisotropy between different pH conditions, it has been revealed that the degree of expansion of random-coiled gellan chains varies with pH. These results indicate that the effect of pH is explained by the change in the anionic nature of gellan chains rather than in the shielding effect of hydrogen ions surrounding gellan chains as a cation species. [Copyright &y& Elsevier]

Abstract: The purpose of this study was to investigate the formation characteristics of oil-in-water (O/W) emulsion droplets in the presence of electrolyte by microchannel (MC) emulsification using differently charged surfactants. Droplet formation was conducted by pressurizing a dispersed phase (refined soybean oil) via 23,348 asymmetric through-holes micro fabricated on a 24mm×24-mm silicon chip into a continuous phase in the presence of a surfactant (1.0wt%) and an electrolyte (NaCl) (0–1.0mol/L). Monodisperse O/W emulsions with an average droplet diameter (d av,drop) of 26μm and a coefficient of variation (CV) below 5% were produced from the asymmetric through-holes when the NaCl concentration was lower than a threshold level that is 0.3mol/L for sodium dodecyl sulfate (SDS) and 0.5mol/L for polyoxyethylene (20) sorbitan monolaurate (Tween 20). Further increase in the NaCl concentration resulted in increase of the d av,drop and CV of the resultant O/W emulsions, which is due to unstable and unsmooth motion of the oil–water interface during droplet formation. In the presence of SDS, it was found that interfacial tension must be higher than a threshold level (c.a. 0.9mN/m) in order to achieve stable droplet formation by MC emulsification. The ζ-potential on the droplet and chip surfaces was negative, and their absolute value decreased with increasing the NaCl concentration. The ζ-potential results also indicated that repulsive electrostatic interaction between the droplet and chip surfaces in the presence of NaCl is high for SDS and negligible for Tween 20. The difference in their electrostatic interaction is assumed to affect the smoothness of droplet formation and the behavior of the droplets formed. [Copyright &y& Elsevier]

Abstract: In clinical trials, acotiamide hydrochloride (acotiamide: Z-338) has been reported to be useful in the treatment of functional dyspepsia. Here, we investigated the effects of acotiamide on gastric contraction and emptying activities in rats in comparison with itopride hydrochloride (itopride) and mosapride citrate (mosapride). We also examined in vitro the compound''s inhibitory effect on acetylcholinesterase (AChE) activity derived from rat stomach. In in vivo studies, acotiamide (30 and 100mg/kg s.c.) and itopride (100mg/kg s.c.) markedly enhanced normal gastric antral motility in rats. In gastric motility dysfunction models, acotiamide (100mg/kg s.c.) and itopride (100mg/kg s.c.) improved both gastric antral hypomotility and the delayed gastric emptying induced by clonidine, an α2-adrenoceptor agonist. In contrast, mosapride (10mg/kg s.c.) had no effect on these models. Like the AChE inhibitors itopride (30mg/kg s.c.) and neostigmine (10μg/kg s.c.), acotiamide (10mg/kg s.c.) also clearly enhanced gastric body contractions induced by electrical stimulation of the vagus, which were abolished by atropine and hexamethonium, whereas mosapride (3 and 10mg/kg s.c.) did not. In in vitro studies, acotiamide concentration-dependently inhibited rat stomach-derived AChE activity (IC50 =2.3μmol/l). In addition, stomach tissue concentrations of acotiamide after administration at 10mg/kg s.c. were sufficient to produce inhibition of AChE activity in rat stomach. These results suggest that acotiamide stimulates gastric motility and improves gastric motility dysfunction in rats by inhibiting AChE activity, and may suggest a role for acotiamide in improving gastric motility dysfunction in patients with functional dyspepsia. [Copyright &y& Elsevier]