ALBERT

Description: Ultrasound reversibly alters the structure of polymerized fibrin, an effect that could influence tissue-plasminogen activator (t-PA) binding. We have, therefore, characterized the effects of ultrasound on binding of t-PA to fibrin using a novel system in which radiolabeled, active-site blocked, single chain tissue-plasminogen activator flowed through a fibrin gel at constant rate, and specific binding was determined by monitoring incorporation of radiolabel. Results using polymerized fibrin were compared with those using a surface of fibrin immobilized on Sepharose beads in a similar system. Interaction of t-PA with surface-immobilized fibrin involved two classes of binding sites (Kd = 31 nmol/L and 244 nmol/L) and a maximum binding ratio of 3.8 mol t-PA/mol fibrin. Ultrasound increased Kd for the high affinity site to 46 nmol/L (P 

Description: Despite multiple disparate prognostic risk analysis systems for evaluating clinical outcome for patients with myelodysplastic syndrome (MDS), imprecision persists with such analyses. To attempt to improve on these systems, an International MDS Risk Analysis Workshop combined cytogenetic, morphological, and clinical data from seven large previously reported risk-based studies that had generated prognostic systems. A global analysis was performed on these patients, and critical prognostic variables were re-evaluated to generate a consensus prognostic system, particularly using a more refined bone marrow (BM) cytogenetic classification. Univariate analysis indicated that the major variables having an impact on disease outcome for evolution to acute myeloid leukemia were cytogenetic abnormalities, percentage of BM myeloblasts, and number of cytopenias; for survival, in addition to the above, variables also included age and gender. Cytogenetic subgroups of outcome were as follows: “good” outcomes were normal, −Y alone, del(5q) alone, del(20q) alone; “poor” outcomes were complex (ie, ≥3 abnormalities) or chromosome 7 anomalies; and “intermediate” outcomes were other abnormalities. Multivariate analysis combined these cytogenetic subgroups with percentage of BM blasts and number of cytopenias to generate a prognostic model. Weighting these variables by their statistical power separated patients into distinctive subgroups of risk for 25% of patients to undergo evolution to acute myeloid leukemia, with: low (31% of patients), 9.4 years; intermediate-1 (INT-1; 39%), 3.3 years; INT-2 (22%), 1.1 years; and high (8%), 0.2 year. These features also separated patients into similar distinctive risk groups for median survival: low, 5.7 years; INT-1, 3.5 years; INT-2, 1.2 years; and high, 0.4 year. Stratification for age further improved analysis of survival. Compared with prior risk-based classifications, this International Prognostic Scoring System provides an improved method for evaluating prognosis in MDS. This classification system should prove useful for more precise design and analysis of therapeutic trials in this disease.

Description: Ultrasound reversibly alters the structure of polymerized fibrin, an effect that could influence tissue-plasminogen activator (t-PA) binding. We have, therefore, characterized the effects of ultrasound on binding of t-PA to fibrin using a novel system in which radiolabeled, active-site blocked, single chain tissue-plasminogen activator flowed through a fibrin gel at constant rate, and specific binding was determined by monitoring incorporation of radiolabel. Results using polymerized fibrin were compared with those using a surface of fibrin immobilized on Sepharose beads in a similar system. Interaction of t-PA with surface-immobilized fibrin involved two classes of binding sites (Kd = 31 nmol/L and 244 nmol/L) and a maximum binding ratio of 3.8 mol t-PA/mol fibrin. Ultrasound increased Kd for the high affinity site to 46 nmol/L (P 

Description: All current classifications for myelodysplastic syndromes (MDS) require the identification of the blast population. From the FAB (1976) to the WHO (1999) new criteria such as the results of cytogenetic analysis have been introduced but the percentage of blasts remains a major factor in diagnosis, subclassification and prognosis. The definition of a blast cell is still based on those proposed in 1976 by the FAB group, but it is unclear that it has been applied in the same manner worldwide. Since the WHO has changed the definition for AML (minimum criterion is 20% blasts) and since RAEB has been divided into two groups (5 to 9 and 10 to 19% blasts respectively) it has become clear that the definition of blasts of granulocyte lineage should be more precise. Definition: Experts in morphology from the IWG on MDS have proposed that all cells from undifferentiated blast (without granules) to but not including the promyelocyte would qualify as “blasts”. A promyelocyte starts with the appearance of a “clearly visible Golgi zone” independently of the number of granules. Mature granulocyte starts with disappearance of cytoplasmic basophilia and more mature nucleus. Methodology: To verify agreement between experts on this new definition, a unique digital picture was produced from the bone marrow smear of an AML patient with FAB M2 by the association of 150 consecutive native pictures (600x800 pixels). The mosaic picture is 8340x2386 pixels (about 30 M in jpeg format or 16 M in pdf). All the 265 nucleated cells have been numbered and a drop down menu for choices was included. The picture was placed on the server of the MDS Foundation (http://www.mds-foundation.org/goasguenfollowup) and after evaluation the results were automatically sent to the MDS foundation center and registered. The five experts evaluated exactly the same cells (numbered from 1 to 265) and results were submitted for statistical analysis. Results: for 176 cells (66.6%) there was complete concordance (5/5) and for 60 others (22.7%) concordance was 4/5. If we consider that concordance of at least 4/5 is acceptable, we obtained 89.4% good concordance. Moreover, 23 cells (8.7%) had a concordance of 3/5 while only 5 (1.89%) had a concordance of 2/5. We conclude that these definitions of blasts and promyelocytes are reproducible and may help to standardize the classification of AML and MDS. All experts would have produced the same diagnosis since standard deviations of the percentages of various cell types were very low. Conclusion: the production of large field digital pictures may be very useful for education and quality control in morphology. In addition, use of such images may help to provide a new approach to difficult cells and may be useful in proposing new criteria for classification. Table: Minimum, maximum and mean percentage of cells for 5 experts % of cells Minimum Maximum Mean Standard deviation Blasts 58.1 61.7 59.9 1.54 Promyelocytes 12.2 22.3 17.7 4.82 Matures cells 14.4 21.6 18.8 3.12