Increasing hematopoietic microchimerism is a reliable indicator of incipient AML relapse

Introduction: The reoccurrence or increase in autologous hematopoiesis after allogeneic transplantation has been linked to incipient leukemia relapse. However, the importance of such an emergency regarding microchimerism (i.e. mixed chimerism below 1% of autologous cells) still remains controversial, as fluctuating microchimerism can be observed for a very long time after transplantation. Methods: Using real‐time PCR (RQ‐PCR), we compare peripheral blood samples obtained from patients with acute myeloid leukemia (AML) before hematological relapse and those taken during complete remission (i.e. either complete cytogenetic remission or complete molecular remission where applicable). By comparison of these two groups, we describe microchimerism dynamics clearly connected with imminent AML relapse. Additionally, we compare applicability of RQ‐PCR and conventional PCR with fragment analysis. Results: Mere reappearance of autologous hematopoiesis within patients with complete donor chimerism is alarming, and another sample with further increase confirms ongoing relapse. In case of patients with continuous microchimerism, another two consecutive samples with increasing trend are required. RQ‐PCR predicted a significantly higher number of hematological relapses (87%vs. 39%) with a median anticipation period of 33 days, 26 days earlier than conventional PCR (P = 0.0002). Moreover, the outcome of microchimerism dynamics was in complete agreement with monitoring of minimal residual disease when analyzed from the same cell compartment. Conclusion: Within this paper, we emphasize the importance of microchimerism monitoring as a reliable indicator of incipient AML relapse, especially in patients where no other specific molecular marker is available.     

Amalgam Substitutes: A Critical Analysis

Purpose: Quality standards for restorations recently have been defined in Switzerland. Amalgam substitutes must meet restoration Grade 2 requirements (i.e., pulp and dental hard substance must be preserved, and both form and function of the tooth have to be reconstituted). The pertinent operative technique has to be simple and amalgam‐like. A minimum service life of 8 years is required. This in vitro study investigated the clinical potential of several amalgam substitutes, taking into account the operative requirements, the defined restorative guidelines, and the required service life. Materials and Methods: Potential amalgam substitutes evaluated in this study included compomers (Compoglass, Dyract, Dyract AP, Elan, F 2000) and resin‐based composites (Alert, Ariston, Definite, Nulite, Solitaire, Surefil). The composites Adaptic and Tetric Cream, using a simplified placement technique, were tested as negative and positive controls, respectively. Marginal adaptation and wear properties were measured in vitro in mixed Class II cavities. Relative radiopacity was measured in terms of millimeters of equivalent aluminum. Results: All compomers showed a radiopacity of 2.5 mm or more aluminum. Only Dyract AP and Elan were more wear resistant than amalgam. After stressing, the percentage of continuous margin was at best 31% overall and 17% in dentin only. Among resin‐based composites, the minimum requirements of radiopacity were fulfilled only by Alert, Surefil, and Tetric. Only Definite, Surefil, Solitaire, and Tetric exhibited wear resistance greater than amalgam. After stressing, the best marginal qualities were 41% continuous margin overall, and 8% in dentin only. CLINICAL SIGNIFICANCE Based on the requirements set for amalgam substitutes, results for the materials tested in this study indicated poor marginal quality and potential risk of secondary caries. Currently, the use of amalgam substitutes for stress‐bearing restorations in permanent teeth cannot be recommended without serious cautions. This is particularly true if a dynamic performance quality of the restorations is demanded, which guarantees the achievement of the restorative targets for 8 years, according to recently adopted quality standards.