Novel mouse xenograft models reveal a critical role of CD4+ T cells in the proliferation of EBV-infected T and NK cells

Epstein-Barr virus (EBV), a ubiquitous B-lymphotropic herpesvirus, ectopically infects T or NK cells to cause severe diseases of unknown pathogenesis, including chronic active EBV infection (CAEBV) and EBV-associated hemophagocytic lymphohistiocytosis (EBV-HLH). We developed xenograft models of CAEBV and EBV-HLH by transplanting patients' PBMC to immunodeficient mice of the NOD/Shi-scid/IL-2Rγ(null) strain. In these models, EBV-infected T, NK, or B cells proliferated systemically and reproduced histological characteristics of the two diseases. Analysis of the TCR repertoire expression revealed that identical predominant EBV-infected T-cell clones proliferated in patients and corresponding mice transplanted with their PBMC. Expression of the EBV nuclear antigen 1 (EBNA1), the latent membrane protein 1 (LMP1), and LMP2, but not EBNA2, in the engrafted cells is consistent with the latency II program of EBV gene expression known in CAEBV. High levels of human cytokines, including IL-8, IFN-γ, and RANTES, were detected in the peripheral blood of the model mice, mirroring hypercytokinemia characteristic to both CAEBV and EBV-HLH. Transplantation of individual immunophenotypic subsets isolated from patients' PBMC as well as that of various combinations of these subsets revealed a critical role of CD4+ T cells in the engraftment of EBV-infected T and NK cells. In accordance with this finding, in vivo depletion of CD4+ T cells by the administration of the OKT4 antibody following transplantation of PBMC prevented the engraftment of EBV-infected T and NK cells. This is the first report of animal models of CAEBV and EBV-HLH that are expected to be useful tools in the development of novel therapeutic strategies for the treatment of the diseases.     

Draft Genome Sequence of the Yeast Kazachstania telluris CBS 16338 Isolated from Forest Soil in Ireland

Mycopathologia - Draft genomes of several Kazachstania species, a large group of ascomycetous budding yeasts, have been recently published. However, there is none yet available for pathogenic...     

Sublethal doses of surfactants induce premature senescence in normal human skin cells

We evaluated the cytotoxicity of surfactants in human cells. Synthetic surfactants showed different cytotoxicity levels depending on their structures. The cytotoxicity of commercial washing products was determined mainly by the contents of surfactants. All of them induced premature senescence in normal cells, but not in tumor-derived or immortalized cells, under sublethal conditions. Residual surfactants might be a risk factor for skin aging.     

Polyphenolic compounds in clove and pimento and their antioxidative activities

Two new polyphenolic glucosides, 6'-O-acetylisobiflorin (1) and (2S)-3-(4-hydroxy-3-methoxyphenyl)-propane-1,2-diol 1-O-(6'-O-galloyl)-β-D-glucoside (2), were respectively isolated from the flower buds of Syzygium aromaticum and berries of Pimenta dioica. Each structure was elucidated on the basis of spectral analyses (NMR, MS and [α](D)) and chemical conversion. A total of twenty-seven known compounds from the plants were also characterized. The antioxidative activity of their extracts and the twenty-nine isolates including gallo- and ellagitannins was estimated by oxygen radical absorbance capacity (ORAC) assay, and eugenol (3), which was the most abundant ingredient in each plant extract, showed the most potent antioxidative activity [ORAC value of 39,270 μmol TE (trolox equivalent)/g].     

2-O-alpha-D-glucopyranosyl-L-ascorbic acid scavenges 1,1-diphenyl-2-picrylhydrazyl radicals via a covalent adduct formation

The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging mechanism of 2-O-alpha-D-glucopyranosyl-L-ascorbic acid (AA-2G) was studied. We found two undefined products, named X and Y, in the reaction mixture of AA-2G and the DPPH radical under acidic conditions by HPLC analysis. The reaction mixture was further subjected to LC-MS analysis. X was found to be a covalent adduct of AA-2G and the DPPH radical. On the other hand, Y could not be identified, probably because it was a mixture. A time-course study of the radical-scavenging reaction revealed that one molecule of AA-2G scavenged one molecule of DPPH radical to generate an AA-2G radical, which readily reacted with another molecule of the DPPH radical to form a covalent adduct (X). Subsequently, this adduct slowly quenched a third molecule of the DPPH radical, resulting in reaction products (Y). Therefore, one molecule of AA-2G has only one oxidizable -OH group, but can scavenge three molecules of the DPPH radical. The radical-scavenging mechanism of AA-2G elucidated in this study should be useful in understanding the biological roles of AA-2G per se in the food and cosmetic fields.     

Structure-activity relationship of chalcones and related derivatives as ligands for detecting of beta-amyloid plaques in the brain

A series of novel chalcones and their related derivatives were synthesized and evaluated as beta-amyloid imaging probes. In the structure-activity relationship of binding affinities to synthetic Abeta(1-42) aggregates, compound 14 displayed the highest binding affinity in vitro. beta-Amyloid plaques in the Alzheimer's model mouse brain were visualized with 14. In biodistribution studies using normal mice, [(125)I]14 showed good brain uptake (2.56% ID/g, 2min postinjection) and rapid washout from the brain (0.21% ID/g, 60min postinjection). These results suggest that [(125)I]14 should be further investigated as a potentially useful beta-amyloid imaging probe.     

The Vitamin D Analogue ED71 but Not 1,25(OH)2D3 Targets HIF1α Protein in Osteoclasts

Although both an active form of the vitamin D metabolite, 1,25(OH)₂D₃, and the vitamin D analogue, ED71 have been used to treat osteoporosis, anti-bone resorbing activity is reportedly seen only in ED71- but not in 1,25(OH)₂D₃ -treated patients. In addition, how ED71 inhibits osteoclast activity in patients has not been fully characterized. Recently, HIF1α expression in osteoclasts was demonstrated to be required for development of post-menopausal osteoporosis. Here we show that ED71 but not 1,25(OH)₂D₃, suppress HIF1α protein expression in osteoclasts in vitro. We found that 1,25(OH)₂D₃ or ED71 function in osteoclasts requires the vitamin D receptor (VDR). ED71 was significantly less effective in inhibiting M-CSF and RANKL-stimulated osteoclastogenesis than was 1,25(OH)₂D₃ in vitro. Downregulation of c-Fos protein and induction of Ifnβ mRNA in osteoclasts, both of which reportedly block osteoclastogenesis induced by 1,25(OH)₂D₃ in vitro, were both significantly higher following treatment with 1,25(OH)₂D₃ than with ED71. Thus, suppression of HIF1α protein activity in osteoclasts in vitro, which is more efficiently achieved by ED71 rather than by 1,25(OH)₂D₃, could be a reliable read-out in either developing or screening reagents targeting osteoporosis.     

“I Can't Find Anything Wrong: It Must Be a Pulmonary Embolism”: Diagnosing Suspected Pulmonary Embolism in Primary Care,a Qualitative Study

Background

Before using any prediction rule oriented towards pulmonary embolism (PE), family physicians (FPs) should have some suspicion of this diagnosis. The diagnostic reasoning process leading to the suspicion of PE is not well described in primary care.

Objective

to explore the diagnostic reasoning of FPs when pulmonary embolism is suspected.

Method

Semi-structured qualitative interviews with 28 FPs. The regional hospital supplied data of all their cases of pulmonary embolism from June to November 2011. The patient''s FP was identified where he/she had been the physician who had sent the patient to the emergency unit. The first consecutive 14 FPs who agreed to participate made up the first group. A second group was chosen using a purposeful sampling method. The topic guide focused on the circumstances leading to the suspicion of PE. A thematic analysis was performed, by three researchers, using a grounded theory coding paradigm.

Results

In the FPs'' experience, the suspicion of pulmonary embolism arose out of four considerations: the absence of indicative clinical signs for diagnoses other than PE, a sudden change in the condition of the patient, a gut feeling that something was seriously wrong and an earlier failure to diagnose PE. The FPs interviewed did not use rules in their diagnostic process.

Conclusion

This study illustrated the diagnostic role of gut feelings in the specific context of suspected pulmonary embolism in primary care. The FPs used the sense of alarm as a tool to prevent the diagnostic error of missing a PE. The diagnostic accuracy of gut feelings has yet to be evaluated.