Semantic transparency and masked morphological priming: an ERP investigation

The role of semantics in the segmentation of morphologically complex words was examined using event-related potentials (ERPs) recorded to target words primed by semantically transparent (hunter-hunt,) opaque (corner-corn), and orthographically related (scandal-scan) masked primes. Behavioral data showed that only transparent items gave rise to priming. The ERP data showed both N250 and the N400 effects with transparent items generating greater priming than orthographic or opaque. Furthermore, priming effects across conditions revealed the existence of a significant linear trend, with transparent items showing the greatest effects and orthographic items the smallest, suggesting that these priming effects vary as a function of morphological structure and semantic transparency. The results are discussed in terms of a model of morphological processing.     

Quantitative chemical exchange saturation transfer (qCEST) MRI – omega plot analysis of RF‐spillover‐corrected inverse CEST ratio asymmetry for simultaneous determination of labile proton ratio and exchange rate

Chemical exchange saturation transfer (CEST) MRI is sensitive to labile proton concentration and exchange rate, thus allowing measurement of dilute CEST agent and microenvironmental properties. However, CEST measurement depends not only on the CEST agent properties but also on the experimental conditions. Quantitative CEST (qCEST) analysis has been proposed to address the limitation of the commonly used simplistic CEST‐weighted calculation. Recent research has shown that the concomitant direct RF saturation (spillover) effect can be corrected using an inverse CEST ratio calculation. We postulated that a simplified qCEST analysis is feasible with omega plot analysis of the inverse CEST asymmetry calculation. Specifically, simulations showed that the numerically derived labile proton ratio and exchange rate were in good agreement with input values. In addition, the qCEST analysis was confirmed experimentally in a phantom with concurrent variation in CEST agent concentration and pH. Also, we demonstrated that the derived labile proton ratio increased linearly with creatine concentration (P < 0.01) while the pH‐dependent exchange rate followed a dominantly base‐catalyzed exchange relationship (P < 0.01). In summary, our study verified that a simplified qCEST analysis can simultaneously determine labile proton ratio and exchange rate in a relatively complex in vitro CEST system. Copyright © 2015 John Wiley & Sons, Ltd.     

Masked priming and ERPs dissociate maturation of orthographic and semantic components of visual word recognition in children

This study examined the time‐course of reading single words in children and adults using masked repetition priming and the recording of event‐related potentials. The N250 and N400 repetition priming effects were used to characterize form‐ and meaning‐level processing, respectively. Children had larger amplitude N250 effects than adults for both shorter and longer duration primes. Children did not differ from adults on the N400 effect. The difference on the N250 suggests that automaticity for form processing is still maturing in children relative to adults, while the lack of differentiation on the N400 effect suggests that meaning processing is relatively mature by late childhood. The overall similarity in the children's repetition priming effects to adults' effects is in line with theories of reading acquisition, according to which children rapidly transition to an orthographic strategy for fast access to semantic information from print.     

Direct action of genistein on CFTR

 Human cystic fibrosis transmembrane conductance regulator (CFTR) chloride channels were expressed in oocytes from Xenopus laevis after injection of CFTR cRNA and studied with the two-electrode voltage-clamp and the giant patch techniques. The tyrosine kinase inhibitor genistein alone activated a small chloride current in whole oocytes expressing CFTR and substantially increased the chloride current obtained upon stimulation with forskolin and isobutyl methylxanthine (IBMX). In giant excised patches, genistein was unable to open protein-kinase-A-phosphorylated CFTR channels in the absence of ATP, but increased the ATP-induced CFTR channel currents by a factor of 3.8 ± 1.7. This genistein-mediated potentiation in excised patches is independent of protein phosphatase activity, as it is readily reversible, even after complete inhibition of protein kinase A activity. Involvement of protein tyrosine kinases also seems unlikely, because this effect of genistein is not antagonized by high concentrations of the tyrosine phosphatase inhibitor ortho-vanadate. We, therefore, propose a direct interaction of genistein with CFTR, probably at a nucleotide binding site, which leads to a higher open probability. Received: 10 March 1997 / Received after revision and accepted: 22 April 1997     

Granulocyte transfusions in severe aplastic anemia: an eleven-year experience

Background

Infections, particularly those caused by invasive fungi, are a major cause of death in patients with severe aplastic anemia. The purpose of this study was to analyze our experience with granulocyte transfusions in such patients.

Design and Methods

A retrospective analysis was performed on all patients with severe aplastic anemia who had received granulocyte transfusions between 1997 and 2007 in our institute. Survival to hospital discharge was the primary outcome. Secondary outcomes included microbiological, radiographic and clinical responses of the infection at 7 and 30 days after initiating granulocyte therapy, and post-transfusion absolute neutrophil count, stratified by HLA alloimmunization status.

Results

Thirty-two patients with severe aplastic anemia underwent granulocyte transfusions; the majority had received horse antithymocyte globulin and cyclosporine A. One quarter of patients had demonstrable HLA alloimmunization prior to the initiation of granulocyte therapy. Infections were evenly divided between invasive bacterial and fungal infections unresponsive to maximal antibiotic and/or antifungal therapy. The median number of granulocyte components transfused was nine (range, 2–43). The overall survival to hospital discharge was 58%. Survival was strongly correlated with hematopoietic recovery. Among the 18 patients who had invasive fungal infections, 44% survived to hospital discharge. Response at 7 and 30 days correlated with survival. The mean post-transfusion absolute neutrophil count did not differ significantly between response groups (i.e. patients grouped according to whether they had complete or partial resolution of infection, stable disease or progressive infection). There was also no difference in mean post-transfusion absolute neutrophil count between the patients divided according to HLA alloimmunization status.

Conclusions

Granulocyte transfusions may have an adjunctive role in severe infections in patients with severe aplastic anemia. HLA alloimmunization is not an absolute contraindication to granulocyte therapy.     

Species-specific transformation of T cells by HV(MNE)

HV(MNE) is an Epstein-Barr virus (EBV)-like lymphocryptovirus (LCV) originally isolated from a Macaca nemestrina with CD8(+) T cell mycosis fungoides/cutaneous T cell lymphoma (Blood 98 (2001), 2193). HV(MNE) transforms rabbit T cells in vitro and causes T cell lymphoma in New Zealand white rabbits. Here we demonstrate that HV(MNE) also immortalizes T cells from mustached tamarins but not those from owl monkeys, common marmosets, squirrel monkeys, black-capped capuchins, and humans. Cytogenetic and FACS analysis revealed the true origin and T cell lineage of the transformed tamarin T cell lines. Tamarin T cells contained HV(MNE) DNA sequence and displayed a decreased requirement for the IL-2 cytokine for growth. Thus, this EBV-like virus from M. nemestrina differs from the other EBV-like viruses found in nonhuman primates inasmuch as it appears to preferentially transform T cells.