The role of renal expression of the glycosphingolipid verotoxin receptor, globotriaosylceramide, in susceptibility to verotoxin-induced hemolytic uremic syndrome is unclear. We show that a single glycosphingolipid can discriminate multiple specific ligands. Antibody detection of globotriaosylceramide in renal sections does not necessarily predict verotoxin binding. The deoxyglobotriaosylceramide binding profile for verotoxin 1, verotoxin 2 and monoclonal anti-globotriaosylceramide are distinct. Anti-globotriaosylceramide had greater dependency on the intact a-galactose and reducing glucose of globotriaosylceramide than verotoxin 1, while verotoxin 2 was intermediate. These ligands differentially stained human kidney sections. Glomerulopathy is the primary verotoxin-associated pathology in hemolytic uremic syndrome. For most samples, verotoxin 1 immunostaining within adult glomeruli was observed (type A). Some samples, however, lacked glomerular binding (type B). Anti-globotriaosylceramide (and less effectively, verotoxin 2) stained all glomeruli. Verotoxin 1/anti-globotriaosylceramide tubular staining was comparable. Type B glomerular/tubular globotriaosylceramide showed minor, but significant, fatty acid compositional differences. Verotoxin 1 type B glomerular binding became evident following pretreatment with cold acetone, or methyl-b-cyclodextrin, used to deplete cholesterol. Direct visualization, using fluorescein isothiocyanate-verotoxin 1B, showed paediatric, but no adult glomerular staining; this was confirmed by anti-fluorescein isothiocyanate immunostaining. Acetone induced fluorescein isothiocyanate-verotoxin 1B glomerular staining in type A, but poorly in type B samples. Comparison of fluorescein isothiocyanate-verotoxin 1B and native verotoxin 1B deoxyglobotriaosylceramide analogue binding showed an alteration in subspecificity. These studies indicate a marked heterogeneity of globotriaosylceramide expression within renal glomeruli and differential binding of verotoxin 1/verotoxin 2/anti-globotriaosylceramide to the same glycosphingolipid. Verotoxin 1 derivatization can induce subtle changes in globotriaosylceramide binding to significantly affect tissue binding. Heterogeneity in glomerular globotriaosylceramide expression may play a significant (cholesterol-dependent?) role in determining renal pathology following verotoxemia.

Abstract. The Grit scale is a popular measure of achievement-striving behavior. Consisting of two subscales, Consistency of Interests (CI) and Perseverance of Effort (PE), this scale has been repeatedly demonstrated to have high reliability and validity. At the same time, an increasing number of studies explicitly report a low correlation between the subscales and distinct patterns of associations with external measures that each subscale forms. We explored whether there is psychometric evidence that a substantive single grit construct underlies the scale. To answer this question, we investigated the scale structure in a more robust framework than the classical test theory and factor analyses could previously provide. The Russian version of the Grit scale was developed and implemented on a representative sample of high school students ( n = 2,269), and different models of item response theory (IRT), both unidimensional and multidimensional, were compared to find the best fitting model. The results confirmed that the subscales reflect related but independent constructs rather than the whole grit construct. The psychometric properties of the subscales were analyzed with the two-dimensional Partial Credit Model. Both subscales of the Russian version of the Grit scale are unidimensional, have good psychometric properties, and can be used to estimate respondents’ ability.

In recent years, there has been growing interest among researchers in exploring approximate number sense (ANS)—the ability to estimate and discriminate quantities without the use of symbols. Despite the growing number of studies on ANS, there have been no cross‐cultural longitudinal studies to estimate both the development of ANS and the cross‐cultural differences in ANS growth trajectories. In this study, we aimed to estimate the developmental trajectories of ANS from the beginning of formal education to the end of elementary school in two countries, Russia and Kyrgyzstan, which have similar organization of their educational systems but differences in socioeconomic status (SES) and in the results of large‐scale educational assessments. To assess the developmental trajectories of ANS, we used a four‐wave longitudinal study with 416 participants from two countries and applied the mixed effect growth approach and the latent class growth approach. Our analysis revealed that the rate of growth in ANS accuracy was higher for the Russian sample than for the Kyrgyz sample and that this difference remained significant even after controlling for fluid intelligence. We identified two latent classes of growth trajectories: the first class had a significant growth in ANS, whereas the second class had no growth. Comparing the distribution of latent classes within the two countries revealed that there was a significantly larger proportion of schoolchildren from the second class in Kyrgyzstan than in Russia.