Phase contrast electron microscopy: development of thin-film phase plates and biological applications

Phase contrast transmission electron microscopy (TEM) based on thin-film phase plates has been developed and applied to biological systems. Currently, development is focused on two techniques that employ two different types of phase plates. The first technique uses a Zernike phase plate, which is made of a uniform amorphous carbon film that completely covers the aperture of an objective lens and can retard the phase of electron waves by π/2, except at the centre where a tiny hole is drilled. The other technique uses a Hilbert phase plate, which is made of an amorphous carbon film that is twice as thick as the Zernike phase plate, covers only half of the aperture and retards the electron wave phase by π. By combining the power of efficient phase contrast detection with the accurate preservation achieved by a cryotechnique such as vitrification, macromolecular complexes and supermolecular structures inside intact bacterial or eukaryotic cells may be visualized without staining. Phase contrast cryo-TEM has the potential to bridge the gap between cellular and molecular biology in terms of high-resolution visualization. Examples using proteins, viruses, cyanobacteria and somatic cells are provided

Myeloablative conditioning for allo-HSCT in pediatric ALL: FTBI or chemotherapy?—A multicenter EBMT-PDWP study

Although most children with acute lymphoblastic leukemia (ALL) receive fractionated total body irradiation (FTBI) as myeloablative conditioning (MAC) for allogeneic hematopoietic stem cell transplantation (allo-HSCT), it is an important matter of debate if chemotherapy can effectively replace FTBI. To compare outcomes after FTBI versus chemotherapy-based conditioning (CC), we performed a retrospective EBMT registry study. Children aged 2-18 years after MAC for first allo-HSCT of bone marrow (BM) or peripheral blood stem cells (PBSC) from matched-related (MRD) or unrelated donors (UD) in first (CR1) or second remission (CR2) between 2000 and 2012 were included. Propensity score weighting was used to control pretreatment imbalances of the observed variables. 3.054 patients were analyzed. CR1 (1.498): median follow-up (FU) after FTBI (1.285) and CC (213) was 6.8 and 6.1 years. Survivals were not significantly different. CR2 (1.556): median FU after FTBI (1.345) and CC (211) was 6.2 years. Outcomes after FTBI were superior as compared with CC with regard to overall survival (OS), leukemia-free survival (LFS), relapse incidence (RI), and nonrelapse mortality (NRM). However, we must emphasize the preliminary character of the results of this retrospective "real-world-practice" study. These findings will be prospectively assessed in the ALL SCTped 2012 FORUM trial.Transplantation and immunomodulatio

Electron microscopy society of Southern Africa. Proceedings

[No abstract available

Sequence polymorphism systems for quantitative real-time polymerase chain reaction to characterize hematopoietic chimerism-high informativity and sensitivity as well as excellent reproducibility and precision of measurement.

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Guidance to bone morbidity in children and adolescents undergoing allogeneic hematopoietic stem cell transplantation

Abstract Allogeneic hematopoietic stem cell transplantation (HSCT) is widely performed in children and adolescents with hematologic diseases, including very high-risk leukemia. With increasing success and survival rates, the long-term sequelae of HSCT have become important. Here, we provide guidance to the prevention and treatment of the most common bone morbidities—osteoporosis and osteonecrosis—emerging in the context of HSCT in children and adolescents. We give an overview on definitions, symptoms, and diagnostics and propose an algorithm for clinical practice based on discussions within the International Berlin Frankfurt Münster (BFM) Stem Cell Transplantation Committee and the Pediatric Disease Working Party of the European Society for Blood and Marrow Transplantation, our expert knowledge, and a literature review

High dose chemotherapy and autologous hematopoietic cell transplantation for Wilms tumor: a study of the European Society for Blood and Marrow Transplantation

Survival for subgroups of patients with Wilms tumor (WT), such as those who suffer from relapse, is disappointing. Some patients’ treatment plans include high-dose chemotherapy (HDT) with autologous hematopoietic cell transplantation (aHCT), although proof for its benefit is lacking. To increase the level of evidence regarding children with WT receiving aHCT as consolidation of first or second remission (after first relapse), we extracted relevant data from the European Blood and Marrow Transplantation Registry concerning 69 patients. Different HDT regimens were administered, mostly either melphalan-containing (n = 34) or thiotepa-containing (n = 14). For the whole population, 5-year overall survival (OS) and event-free survival (EFS) probabilities were 0.67 (±0.06) and 0.63 (±0.06), respectively (median observation time 7.8 years); for children transplanted in first remission, OS and EFS were 0.69 (±0.09) and 0.72 (±0.08). In univariate analysis, male gender and relapse in multiple sites were associated with lower OS probabilities. The use of a given pretransplant regimen (i.e. melphalan alone versus regimens with multiple drugs) did not seem to influence EFS/OS probability after aHCT, but significantly influenced platelet engraftment (more delayed with thiotepa). We here provide further data to improve the basis for future evidence-based clinical decision-making when using HDT and aHCT in relapsed/refractory WT