Clearance of circulating activated platelets in polycythemia vera and essential thrombocythemia

Essential thrombocythemia (ET) and polycythemia vera (PV) are characterized by persistent platelet activation. The mechanisms involved in their clearance are poorly characterized. In the present study, we report that leukocytes were actively involved in platelet disposal in 51 patients with ET and 30 with PV, but not in 70 age- and sex-matched controls. The fraction of circulating neutrophils and monocytes that had phagocytosed platelets, as assessed by flow cytometry, was significantly higher in patients with PV or ET, independently of hydroxyurea treatment, than in controls. Platelet phagocytosis by circulating leukocytes was confirmed by confocal and electron microscopy. The lack of effect of hydroxyurea, which disrupts the P-selectin/P-selectin glycoprotein ligand 1 (PSGL-1) interaction, suggests a P-selectin-independent mechanism. This hypothesis was confirmed in an ad hoc animal model based on the in vivo injection of activated platelets from P-selectin(+/+) and P-selectin(-/-) mice. P-selectin expression was associated with an earlier and effective clearance of platelets by neutrophils. A second delayed, P-selectin-independent phase actively involved monocytes. Our results suggest that phagocytic clearance of platelets by leukocytes occurs in PV and ET, possibly involving P-selectin-dependent and -independent pathways, thus representing a novel mechanism to remove activated platelets from the circulation.     

Trauma reminders and PTSD symptoms in children three years after a terrorist attack in Beslan

As a consequence of a terrorist attack, children may experience trauma-related internal and external reminders that are directly linked to their physical and psychological health. We assessed PTSD and trauma reminders in 58 school-age children three years after the terrorist attack in Beslan, Russia in 2004, as well as their association with degree of exposure, psychological distress and coping. Findings revealed a prevalence of situational trauma reminders associated with high levels of distress in more exposed children. The presence of PTSD was predicted by level of exposure to the attack, frequency of exposure to trauma reminders, and support seeking as a coping strategy. Findings are discussed in light of the socio-political climate in Beslan and distress experienced by the population three years after the attack.     

The Italian version of the obsessive compulsive inventory: its psychometric properties on community and clinical samples

The aim of the study was to evaluate psychometric properties of the Obsessive Compulsive Inventory (OCI) on Italian community and clinical samples. The Italian version of the 42-item OCI was administered to a sample of 340 individuals belonging to the general population and to 88 patients with obsessive compulsive (OCD) or other anxiety disorders. Four different internal structures of the OCI were compared through confirmatory factor analysis (CFA): the figures for the model with six factors and 18 items (OCI-R) met the best criteria for adequacy of fit. The six scales showed on average a 10% of common variance in the community sample and 8% in the clinical sample. The OCI-R subscales showed good internal consistency and temporal stability, with the exception of washing and mental neutralizing subscales which showed a strong alpha coefficient only in the OCD sample. Psychometric data for the OCI-R were insensitive to age and sex, whereas an effect of education was found. Concurrent validity was demonstrated, since the OCI-R subscales showed a pattern of specific correlations with another conceptually related self-report measure. Moreover, although the OCI-R was positively correlated with measures of depression, anxiety, and worry, the correlations were weaker than those with the other measure of OCD symptoms. The OCI-R clearly differentiated OCD patients from non-OCD anxious patients and nonclinical controls with the exception of hoarding subscale. However, the hoarding scale discriminated OCD patients who presented hoarding symptoms from OCD counterparts without such symptoms. Thus, the OCI-R proved to be a reliable and valid measure of obsessive compulsive symptoms in the Italian context.     

Cognitive abilities as precursors of the early acquisition of mathematical skills during first through second grades

The present longitudinal study was designed to investigate precursors of mathematics achievement in children. A total of 72 children were tested at both the beginning and end of first and second grades on measures of the following cognitive abilities: phonology, counting skills, short-term memory, working memory, and verbal and performance IQ. Path analysis models revealed differences in the variables predicting mathematics skills of first and second graders. Specifically, in first graders both short-term and working memory measures mediated the role of verbal IQ in predicting mathematics skills. Also, there was a direct relationship between performance IQ and mathematics at first grade. In contrast, in the longitudinal model, working memory measured both in first and second grades predicted mathematics achievement, whereas the relationship between performance IQ and mathematics disappeared. In conclusion, the results demonstrated that mathematics learning is predicted not by phonology or counting skills and that working memory is a plausible mediator in predicting mathematics achievement in primary school age children.