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

Nanobeam precession-Assisted 3D electron diffraction reveals a new polymorph of hen egg-white lysozyme

Recent advances in 3D electron diffraction have allowed the structure determination of several model proteins from submicrometric crystals, the unit-cell parameters and structures of which could be immediately validated by known models previously obtained by X-ray crystallography. Here, the first new protein structure determined by 3D electron diffraction data is presented: A previously unobserved polymorph of hen egg-white lysozyme. This form, with unit-cell parameters a = 31.9, b = 54.4, c = 71.8Å, β = 98.8°, grows as needle-shaped submicrometric crystals simply by vapor diffusion starting from previously reported crystallization conditions. Remarkably, the data were collected using a low-dose stepwise experimental setup consisting of a precession-Assisted nanobeam of ∼150nm, which has never previously been applied for solving protein structures. The crystal structure was additionally validated using X-ray synchrotron-radiation sources by both powder diffraction and single-crystal micro-diffraction. 3D electron diffraction can be used for the structural characterization of submicrometric macromolecular crystals and is able to identify novel protein polymorphs that are hardly visible in conventional X-ray diffraction experiments. Additionally, the analysis, which was performed on both nanocrystals and microcrystals from the same crystallization drop, suggests that an integrated view from 3D electron diffraction and X-ray microfocus diffraction can be applied to obtain insights into the molecular dynamics during protein crystal growth

3D electron diffraction investigation on Hen Egg-White Lysozyme crystals

New perspectives have been opened in recent years on the crystallographic analysis of submicrometric protein crystals by electron diffraction (ED), commonly referred as MicroED or 3D ED. This technique exploits the strong interaction of a parallel beam of high energy electrons with matter which is able to produce accurate diffraction patterns from crystals of a few hundred of nanometers. Despite stimulating results obtained on different protein crystals, many efforts are still needed in order to improve technical aspects of the ED analysis, as the preparation of good working samples and the spatial resolution for diffraction collections. The analysis of nanocrystals by using a precession­assisted electron nanobeam together with STEM imaging has demonstrated to provide accurate diffraction data in this regard, especially for the investigation of beam sensitive samples because of the small illuminated area in comparison to the generally performed continuous rotation data collections. To evaluate such ED methodology on macromolecular specimens, we used protein crystals of the Hen Egg White Lysozyme as first case study. Crystals were deposited on carbon­coated grids, followed by blotting and vitrification by plunging the grids into liquid ethane. Diffraction data collections on a new monoclinic polymorph and on the known tetragonal form of Lysozyme were obtained using precession of the electron nanobeam and have led to the solution via molecular replacement and the refinement of both structures. Notably, findings on the novel monoclinic polymorph suggest a new path to characterize the molecular dynamics associated to protein crystal growth. The promising results obtained will be presented together to an informative picture of ED and its future perspectives

3D electron diffraction investigation on Hen Egg-White Lysozyme crystals

New perspectives have been opened in recent years on the crystallographic analysis of submicrometric protein crystals by electron diffraction (ED), commonly referred as MicroED or 3D ED. This technique exploits the strong interaction of a parallel beam of high energy electrons with matter which is able to produce accurate diffraction patterns from crystals of a few hundred of nanometers. Despite stimulating results obtained on different protein crystals, many efforts are still needed in order to improve technical aspects of the ED analysis, as the preparation of good working samples and the spatial resolution for diffraction collections. The analysis of nanocrystals by using a precession­assisted electron nanobeam together with STEM imaging has demonstrated to provide accurate diffraction data in this regard, especially for the investigation of beam sensitive samples because of the small illuminated area in comparison to the generally performed continuous rotation data collections. To evaluate such ED methodology on macromolecular specimens, we used protein crystals of the Hen Egg White Lysozyme as first case study. Crystals were deposited on carbon­coated grids, followed by blotting and vitrification by plunging the grids into liquid ethane. Diffraction data collections on a new monoclinic polymorph and on the known tetragonal form of Lysozyme were obtained using precession of the electron nanobeam and have led to the solution via molecular replacement and the refinement of both structures. Notably, findings on the novel monoclinic polymorph suggest a new path to characterize the molecular dynamics associated to protein crystal growth. The promising results obtained will be presented together to an informative picture of ED and its future perspectives