Characterization of the transport of lysine-containing dipeptides by PepT1orthologs expressed in Xenopus laevis oocytes.

During digestion, dietary proteins cleaved in di and tri-peptides are translocated from the intestinal lumen into the enterocytes via PepT1 (SLC15A1) using an inwardly directed proton electrochemical gradient. The kinetic properties in various PepT1 orthologs (Dicentrarchus labrax, Oryctolagus cuniculus, Danio rerio) have been explored to determine the transport efficiency of different combinations of lysine, methionine, and glycine. Species-specific differences were observed. Lys-Met resulted the best substrate at all tested potentials in sea bass and rabbit PepT1, whereas in the zebrafish transporter all tested dipeptides (except Gly-Lys) elicited similar currents independently on the charge position or amino acid composition. For the sea bass and rabbit PepT1, kinetic parameters, K0.5 and Imax and their ratio, show the importance of the position of the charged lysine in the peptide. The PepT1 transporter of these species has very low affinity for Lys-Lys and Gly-Lys; this reduces the transport efficiency which is instead higher for Lys-Met and Lys-Gly. PepT1 from zebrafish showed relatively high affinity and excellent transport efficiency for Met-Lys and Lys-Met. These data led us to speculate about the structural determinants involved in substrate interaction according to the model proposed for this transporter

"Delirium Day": A nationwide point prevalence study of delirium in older hospitalized patients using an easy standardized diagnostic tool

Background: To date, delirium prevalence in adult acute hospital populations has been estimated generally from pooled findings of single-center studies and/or among specific patient populations. Furthermore, the number of participants in these studies has not exceeded a few hundred. To overcome these limitations, we have determined, in a multicenter study, the prevalence of delirium over a single day among a large population of patients admitted to acute and rehabilitation hospital wards in Italy. Methods: This is a point prevalence study (called "Delirium Day") including 1867 older patients (aged 65 years or more) across 108 acute and 12 rehabilitation wards in Italian hospitals. Delirium was assessed on the same day in all patients using the 4AT, a validated and briefly administered tool which does not require training. We also collected data regarding motoric subtypes of delirium, functional and nutritional status, dementia, comorbidity, medications, feeding tubes, peripheral venous and urinary catheters, and physical restraints. Results: The mean sample age was 82.0 \ub1 7.5 years (58 % female). Overall, 429 patients (22.9 %) had delirium. Hypoactive was the commonest subtype (132/344 patients, 38.5 %), followed by mixed, hyperactive, and nonmotoric delirium. The prevalence was highest in Neurology (28.5 %) and Geriatrics (24.7 %), lowest in Rehabilitation (14.0 %), and intermediate in Orthopedic (20.6 %) and Internal Medicine wards (21.4 %). In a multivariable logistic regression, age (odds ratio [OR] 1.03, 95 % confidence interval [CI] 1.01-1.05), Activities of Daily Living dependence (OR 1.19, 95 % CI 1.12-1.27), dementia (OR 3.25, 95 % CI 2.41-4.38), malnutrition (OR 2.01, 95 % CI 1.29-3.14), and use of antipsychotics (OR 2.03, 95 % CI 1.45-2.82), feeding tubes (OR 2.51, 95 % CI 1.11-5.66), peripheral venous catheters (OR 1.41, 95 % CI 1.06-1.87), urinary catheters (OR 1.73, 95 % CI 1.30-2.29), and physical restraints (OR 1.84, 95 % CI 1.40-2.40) were associated with delirium. Admission to Neurology wards was also associated with delirium (OR 2.00, 95 % CI 1.29-3.14), while admission to other settings was not. Conclusions: Delirium occurred in more than one out of five patients in acute and rehabilitation hospital wards. Prevalence was highest in Neurology and lowest in Rehabilitation divisions. The "Delirium Day" project might become a useful method to assess delirium across hospital settings and a benchmarking platform for future surveys

Sending Country Policies

This chapter explores the twin central questions of how and why countries of origin reach out to expatriate populations. It first outlines basic concepts and typologies related to sending country policies, focusing particularly on key countries of origin of migrants settled within the European Union. Second, the chapter reviews central explanations for the emergence of sending country policies. However, sending countries do not reach out to their emigrants in equal measure. Differences are therefore examined in the outreach policies of sending countries and in sending countries' transnational relations with diasporas. The last part of the chapter discusses the nexus between sending country policies and migrant integration in the country of residence. On the basis of existing research, the chapter argues that sending country policies may intersect with migrants' integration in a number of ways. For example, migrant sending countries may seek to strengthen the upward mobility of their expatriate citizens in their place of residence abroad, and they may call for greater protection of migrant workers in precarious labour situations. Little is currently known about how migrants and diasporas respond to these policies and how they are perceived by political actors of countries of residence. This is an area for further study. More analysis is also needed to determine the extent that sending country outreach policies aimed at bonding with and supporting citizens abroad challenge territorial policy sovereignty and the strength of receiving countries in agenda-setting in international cooperation on migration and migrant settlement

Thermodynamics of β-Cyclodextrin/Water Interactions

From a purely enthalpic standpoint, the beta-CD hydration, as studied by semiempirical calculations appears improbable, in contrast to experiment. For the spontaneous hydration process, a compensation mechanism, connected to substrate stabilitazion and/or entropy increase, is suggested, on the basis of simple thermodynamic calculations

Temperature effects on the kinetic properties of the rabbit intestinal oligopeptide cotransporter PepT1

The effects of temperature on the functional properties of the intestinal oligopeptide transporter PepT1 from rabbit have been investigated using electrophysiological methods. The dipeptide Gly-Gln at pH 6.5 or 7.5 was used as substrate. Raising the temperature in the range 20-30 \ub0C causes an increase in the maximal transport-associated current (I (max)) with a Q (10) close to 4. Higher temperatures accelerate the rate of decline of the presteady-state currents observed in the absence of organic substrate. The voltage dependencies of the intramembrane charge movement and of the time constant of decline are both shifted towards more negative potentials by higher temperatures. The shift is due to a stronger action of temperature on the outward rate of charge movement compared to the inward rate, indicating a lower activation energy for the latter process. Consistently, the activation energy for the complete cycle is similar to that of the inward rate of charge movement. Temperature also affects the binding rate of the substrate: the K (0.5) -V curve is shifted to more negative potentials by higher temperatures, resulting in a lower apparent affinity in the physiological range of potentials. The overall efficiency of transport, estimated as the I (max) /K (0.5) ratio is significantly increased at body temperature

The Effect on Heat Flux DSC Measurements of Physico-Chemical Properties of the Sample

The physico-chemical properties of different solid state samples have been studied by DSC measurements. The effects on the heat flux variation and profile are disussed