The rare t(4;12)(q11;p13) in an elderly patient with de novo AML with multilineage dysplasia co-expressing stem cell markers

Case report of a translocation : The rare t(4;12)(q11;p13) in an elderly patient with de novo AML with multilineage dysplasia co-expressing stem cell markers

Does this patient have pulmonary embolism?

Context: Experienced clinicians' gestalt is useful in estimating the pretest probability for pulmonary embolism and is complementary to diagnostic testing, such as lung scanning. However, it is unclear whether recently developed clinical prediction rules, using explicit features of clinical examination, are comparable with clinicians' gestalt. If so, clinical prediction rules would be powerful tools because they could be used by less-experienced health care professionals to simplify the diagnosis of pulmonary embolism. Recent studies have shown that the combination of a low pretest probability (using a clinical prediction rule) and a normal result of a D-dimer test reliably excludes pulmonary embolism without the need for further testing. Objective: To evaluate and demonstrate the accuracy of pretest probability assessment for pulmonary embolism using clinical gestalt vs clinical prediction rules. Data Sources: The MEDLINE database was searched for relevant articles published between 1966 and March 2003. Bibliographies of pertinent articles also were scanned for suitable articles. Study Selection: To be included in the analysis, studies were required to have consecutive, unselected patients enrolled; participating physicians in the studies, blinded to the results of diagnostic testing, had to estimate pretest probability of pulmonary embolism; and validated diagnostic methods had to be used to confirm or exclude pulmonary embolism. Data Extraction: Three reviewers independently scanned titles and abstracts for inclusion of studies. An initial MEDLINE search identified 1709 studies, of which 16 involving 8306 patients were included in the final analysis. Data Synthesis: A clinical gestalt strategy was used in 7 studies, and in the low, moderate, and high pretest categories, the rates of pulmonary embolism ranged from 8% to 19%, 26% to 47%, and 46% to 91%, respectively. Clinical prediction rules were used in 10 studies, and 3% to 28%, 16% to 46%, and 38% to 98% in the low, moderate, and high pretest probability groups, respectively, had pulmonary embolism. Conclusions: The clinical gestalt of experienced clinicians and the clinical prediction rules used by physicians of varying experience have shown similar accuracy in discriminating among patients who have a low, moderate, or high pretest probability of pulmonary embolism. We advocate the use of a clinical prediction rule because it has shown to be accurate and can be used by less-experienced clinicians

Application of a strain rate gradient microfluidic device to von Willebrand's disease screening

Von Willebrand's disease (VWD) is the most common inherited bleeding disorder caused by either quantitative or qualitative defects of von Willebrand factor (VWF). Current tests for VWD require relatively large blood volumes, have low throughput, are time-consuming, and do not incorporate the physiologically relevant effects of haemodynamic forces. We developed a microfluidic device incorporating micro-contractions that harnesses well-defined haemodynamic strain gradients to initiate platelet aggregation in citrated whole blood. The microchannel architecture has been specifically designed to allow for continuous real-time imaging of platelet aggregation dynamics. Subjects aged ≥18 years with previously diagnosed VWD or who presented for evaluation of a bleeding disorder, where the possible diagnosis included VWD, were tested. Samples were obtained for device characterization as well as for pathology-based testing. Platelet aggregation in the microfluidic device is independent of platelet amplification loops but dependent on low-level platelet activation, GPIb/IX/V and integrin α IIb β 3 engagement. Microfluidic output directly correlates with VWF antigen levels and is able to sensitively detect aggregation defects associated with VWD subtypes. Testing demonstrated a strong correlation with standard clinical laboratory-based tests. Head-to-head comparison with PFA100® demonstrated equivalent, if not improved, sensitivity for screening aggregation defects associated with VWD. This strain rate gradient microfluidic prototype has the potential to be a clinically useful, rapid and high throughput-screening tool for VWD as well as other strain-dependent platelet disorders. In addition, the microfluidic device represents a novel approach to examine the effects of high magnitude/short duration (ms) strain rate gradients on platelet function