Shiga Toxin and Lipopolysaccharide Induce Platelet-Leukocyte Aggregates and Tissue Factor Release, a Thrombotic Mechanism in Hemolytic Uremic Syndrome

BACKGROUND: Aggregates formed between leukocytes and platelets in the circulation lead to release of tissue factor (TF)-bearing microparticles contributing to a prothrombotic state. As enterohemorrhagic Escherichia coli (EHEC) may cause hemolytic uremic syndrome (HUS), in which microthrombi cause tissue damage, this study investigated whether the interaction between blood cells and EHEC virulence factors Shiga toxin (Stx) and lipopolysaccharide (LPS) led to release of TF. METHODOLOGY/PRINCIPAL FINDINGS: The interaction between Stx or LPS and blood cells induced platelet-leukocyte aggregate formation and tissue factor (TF) release, as detected by flow cytometry in whole blood. O157LPS was more potent than other LPS serotypes. Aggregates formed mainly between monocytes and platelets and less so between neutrophils and platelets. Stimulated blood cells in complex expressed activation markers, and microparticles were released. Microparticles originated mainly from platelets and monocytes and expressed TF. TF-expressing microparticles, and functional TF in plasma, increased when blood cells were simultaneously exposed to the EHEC virulence factors and high shear stress. Stx and LPS in combination had a more pronounced effect on platelet-monocyte aggregate formation, and TF expression on these aggregates, than each virulence factor alone. Whole blood and plasma from HUS patients (n = 4) were analyzed. All patients had an increase in leukocyte-platelet aggregates, mainly between monocytes and platelets, on which TF was expressed during the acute phase of disease. Patients also exhibited an increase in microparticles, mainly originating from platelets and monocytes, bearing surface-bound TF, and functional TF was detected in their plasma. Blood cell aggregates, microparticles, and TF decreased upon recovery. CONCLUSIONS/SIGNIFICANCE: By triggering TF release in the circulation, Stx and LPS can induce a prothrombotic state contributing to the pathogenesis of HUS

Production of citral from geraniol

International audienceThe preparation of porous-layer open-tubular columns for gas—liquid chromatography with graphitized thermal carbon black as a solid support and a polar stationary phase is described. The application of these columns is demonstrated by an example.The reaction products from two oxidation reactions for the production of synthetic citral have been analysed by combined gas chromatography—mass spectrometry. About 30 trace substances rsulting from redox reaction and cyclization of the starting materials were found

Reversible changes on computed tomography scans of the brain during induction therapy for acute lymphoblastic leukemia in children

Children with acute lymphoblastic leukemia (ALL) have been shown to develop changes on computed tomography (CT) scans of the brain. These changes are seen both during and after therapy. Some of the results have been contradictory. Nine children with ALL were examined by CT of the brain during induction therapy. All children showed normal CT scans on the day of diagnosis. One month later all had dilatation of the ventricles and widened sulci. During the next 9 months the CT scans gradually were normalized. We conclude that such changes in CT scans of the brain are transitory and are caused by the high dose of prednisolone administered during induction therapy

Endocrinological late complications after hematopoietic SCT in children

The main challenge for a pediatric hemato-oncologist today is to obtain a cure for the sick child with the minimum of treatment-related complications. Children on their way to achieving adulthood face many risks after hematopoietic SCT (HSCT). Continuous follow-up includes assessment of organ function, focus on vaccinations and screening for secondary malignancies. Updated treatment protocols are already adjusted according to the knowledge obtained on late effects, and the potential risks for complications are well balanced with expected benefits hopefully resulting in decreased potential risk for organ damage but still maintaining an unchanged or improved survival rate. Recent developments on pre-HSCT regimens, such as the introduction of new anticancer regimens and immunosuppressive agents will hopefully contribute to minimize the frequency and the severity of late complications. Knowledge about increased risk for long-term complications due to cancer therapy and pre-HSCT preparative regimens should encourage each caring physician to stick to follow-up protocols and treatment guidelines not only to improve the survival rate of transplanted children but also to improve their quality of life. To achieve adulthood by maintaining cognitive ability and psychosocial skills is the highest goal for an individual to become a competent member of a society. This review of late endocrine complications after HSCT focuses on growth, pubertal development, thyroid disorders and glucose metabolism in long-term survivors

Identification of various exon combinations of the ews/fli1 translocation: An optimized RT-PCR method for paraffin embedded tissue a report by the CWS-Study group - A report by the CWS-study group

Background: Chromosomal translocations t(11;22) (q24;q12) are characteristic of about 80-90% of Ewing's sarcoma family of tumors [bone and soft tissue Ewing's sarcoma and peripheral neuroectodermal tumors (PNET)]. They generate ews/fli1 rearrangements showing great diversity in breakpoint exon combination. In about 5% of Ewing's tumors, ews is fused to the erg gene at 21q22. The various chimeric proteins encoded may function as aberrant oncogenic transcription factors. These specific translocations can be used for exact molecular diagnosis in these poorly differentiated small round-cell tumors. Moreover, the prognostic relevance of different translocational variants has been previously suggested. Furthermore, the sensitive molecular detection of minimal metastatic and residual disease and its clinical significance can be evaluated. To address these questions more definitively in the large number of patients registered in multicenter studies, it is often necessary to access archival paraffin-embedded tumor tissue if no fresh or frozen tumor material is available for analysis by RT (reverse transcription)-PCR. Specific problems arise from formalin-fixed and paraffin-embedded tissue due to the degradation of RNA and insufficient extraction efficiency. Therefore, primer distance and product size are limited for successful PCR amplification. This conflicts with the requirement for identification of various possible exon combinations by PCR simultaneously using one single primer pair with larger distance. Patients: We examined paraffin embedded soft part tumor tissue samples from 47 Ewing's tumor patients. Patients were treated according to either CWS (Cooperative Weichteilsarkomstudie, CWS-91 or CWS-96) or Euro-E.W.I.N.G. 99 therapy protocols. Method: We established a novel RT-PCR method, using 3 different exon specific sets of PCR primer pairs, selected according to the coding ews and fli1 nucleotide sequences (NCBI database), suitable for RT-PCR identification of variant ews/fli1 fusion transcripts in RNA isolated from formalin-fixed, paraffin-embedded tissue. For use in combination with ews-primer, an erg specific primer was selected to alternatively test for ews/erg fusion transcripts. As positive control for the integrity of isolated mRNA, we used the ubiquitously expressed gapdh transcript for RT-PCR amplification in each sample. Results: In 31 cases (= 66%) of 47 paraffin samples of Ewing's tumors analysed, gapdh control indicated adequate quality of RNA. In 16 cases no gapdh control fragment was amplifiable, nevertheless in 2 of these 16 samples distinct ews fusion products could be detected. In 23 cases we identified ews fusion transcripts. Thereof in 65% ews exon 7 being fused to fli1 exon 6 (fusion type I), in 22% to fli1 exon 5 (fusion type II). In 4% each ews exon 10 being juxtaposed to fli1 either exon 6 or exon 5, respectively. An ews/erg fusion was detected in 4% (ews exon 7 fused to erg exon 6). In 10 samples, a gapdh fragment was amplified, but no ews/fli1 or -erg fusion transcript could be identified. The reference pathological review (I. L., Kiel, Germany) disproved the primary histopathology in 5 cases. Conclusions: Using our different sets of exon specific primer pairs, it was possible to detect 4 different breakpoints of ews/fli1 fusion transcripts and the ews/erg fusion by RT-PCR in RNA isolates from formalin-fixed, paraffin-embedded Ewing's tumor tissue. This method can be a very useful alternative in clinical situations (to ensure diagnosis and perform minimal metastatic and residual disease investigations) and in order to assess prognostic significance of translocation subtype when no fresh tumor tissue is available

Prognostic Value of PAX-FKHR Fusion Status in Alveolar Rhabdomyosarcoma: A Report From the Cooperative Soft Tissue Sarcoma Study Group (CWS)

Background. Alveolar Rhabdomyosarcomas (RMA) are characterized by chromosomal translocations, fusing the PAX3 or PAX7 gene with FKHR in about 85%. Previous studies have suggested that the fusion type is associated with prognosis. In order to investigate the predictive value of the PAX-FKHR fusion status on disease outcome of patients with RMA treated in the CWS trials we performed a retrospective analysis. Procedure. Between 1986 and 2004, out of 446 patients with RMA treated in four consecutive CWS trials, tumor samples from 126 patients were available for RT-PCR analysis. Survival depending on fusion status in context with known clinical risk-factors was analyzed. Results. Out of 126 samples, 121 had adequate quality for PAX-FKHR fusion status analysis. PAX-FKHR fusions were detected in 101 samples: 60% PAX3-FKHR and 24% PAX7-FKHR fusions, 17% were fusion-negative. There was no significant difference in survival between patients with PAX3-FKHR versus PAX7-FKHR positive tumors. The fusion transcript negative cohort showed a more favorable outcome than the fusion transcript positive cohort among patients with metastatic disease. From the established clinical risk-factors none was associated with a significantly higher risk of failure or death in a multivariate analysis. Conclusions. PAX-FKHR fusion type was not a significant predictor for survival in our analysis. Moreextensive molecular analyses are needed to identify features with prognostic relevance and useful therapeutic impact. Pediatr Blood Cancer 2011; 57: 406-414. (C) 2011 Wiley-Liss, Inc