Anatomical observations of the pulmonary veins with intracardiac echocardiography and hemodynamic consequences of narrowing of pulmonary vein ostial diameters after radiofrequency catheter ablation of atrial fibrillation

Intracardiac echocardiography was used to explore pulmonary venous (PV) anatomy and to monitor PV stenosis in 31 patients referred for radiofrequency catheter ablation at PV ostia. Interindividual variations in PV anatomy and insertion in the left atrium were observed. Narrowing of PV ostia after radiofrequency catheter ablation did not produce significant hemodynamic changes.     

Pre-B cells in peripheral blood of multiple myeloma patients

Although multiple myeloma is a disease of plasma cells, abnormalities have been detected in both B and T lymphocytes in peripheral blood. Although multiple myeloma patients are deficient in surface Ig (sIg)- positive B lymphocytes, analysis of lymphocytes present in blood indicates an abnormally large pool of circulating pre-B cells. These pre-B cells express BA-1, do not bear sIg, and contain cytoplasmic mu chains. High numbers of pre-B cells occur in 88% of individuals with frank myeloma and in 44% of individuals with monoclonal gammopathy of undetermined significance. Pre-B cells bearing BA-1 differ between patients in their expression of HLA-DR and receptors for peanut agglutinin (PNA). Those pre-B cells in myeloma patients are either BA- 1+ PNA- HLA-DR+ (54% of patients) or BA-1+ PNA+ HLA-DR- (30% of patients), or have a mixture of phenotypes (14% of patients). Pre-B cells of the PNA- phenotype are almost always HLA-DR+, and PNA+ pre-B cells are HLA-DR-. Within the same patient, the pre-B cell population varies by both quantitative and qualitative definitions. The number of pre-B cells may increase 460-fold and temporal shifts of surface phenotype from BA-1+ PNA- to BA-1+ PNA+ or vice versa have been detected. These observations indicate an abnormality in the B lymphocyte differentiation pathway leading to pre-B cells in the periphery that vary in number and cell surface phenotype, and that are unable to express sIg.     

Apparent molecular weight of purified human factor VIII procoagulant protein compared with purified and plasma factor VIII procoagulant protein antigen

We have compared apparent molecular weights of purified factor VIII procoagulant protein (VIII:C) and VIII:C antigen (VIII:CAg) by two different NaDodSO4 gel electrophoretic techniques. In a discontinuous NaDodSO4-7.5% polyacrylamide system, reduced and unreduced VIII:C, purified from commercial factor VIII concentrates by a monoclonal antibody immunoadsorption technique, showed a major doublet at mol wt 0.79 and 0.8 X 10(5) and less intense bands extending up to 1.9 X 10(5). In NaDodSO4-4% polyacrylamide/0.5% agarose gels (NaDodSO4-4% PAAGE), purified VIII:C had a major band of mol wt 1.0 X 10(5), with minor bands of mol wt 0.96, 1.1, 1.4, 1.6, 1.8, 2.2, and 2.4 X 10(5). In NaDodSO4-4% PAAGE of 125I-anti-VIII:C-Fab-VIII:CAg complexes, the major and minor forms of VIII:CAg in purified VIII:C had the same molecular weight as above when calculated by subtracting the molecular weight of 125I-Fab from 125I-Fab-VIII:CAg. In both plasma and factor VIII concentrate, a band of mol wt 2.4 X 10(5) predominated, and minor VIII:CAg forms of mol wt 2.6, 1.8, 1.2 and 1.0 X 10(5) were also visible. We conclude that the molecular weight of plasma VIII:CAg forms agree with those derived from protein stains of purified VIII:C in the NaDodSO4-4% PAAGE system, but that consistently lower molecular weight values are obtained for purified VIII:C in the discontinuous system. Both native and either disaggregated or proteolyzed VIII:C species are present in the purified VIII:C preparation.     

Antithrombin Milano: a new variant with monomeric and dimeric inactive antithrombin III

A qualitative defect of antithrombin III (AT III) has been demonstrated over three generations in eight members of an Italian family by the discrepancy between a normal amount of antigen and decreased antithrombin and anti-Xa activity in the presence or in the absence of heparin. By two-dimensional immunoelectrophoresis in the absence of heparin, two peaks of AT III were present in all patients' plasma. AT III was purified from normal and propositus plasma by sulfate dextran precipitation followed by heparin affinity chromatography. The elution profile of the patient's AT III was abnormal and allowed the separation of two populations of AT III, normal and abnormal. The first fraction (normal AT III) contained AT III activity, migrated as a single peak by two-dimensional immunoelectrophoresis and by sodium dodecyl sulfate- polyacrylamide gel electrophoresis (SDS-PAGE), demonstrated a single band with a molecular weight (mol wt) identical to that of normal AT III (60,000). Conversely, the last fraction, devoid of AT III activity, migrated as a single abnormal peak by two-dimensional immunoelectrophoresis in the absence of heparin. By SDS-PAGE, two bands were observed: one with a mol wt of 60,000 and a second one with a mol wt of 120,000. Western blots clearly demonstrated cross-reactivity of the 120,000 and 60,000 mol wt bands with monospecific antisera to human AT III. Reduction of the 120,000 mol wt band converted it to a single 60,000 mol wt band, suggesting the presence of an abnormal dimeric form of AT III. The name AT III Milano is proposed for this new variant.     

BCL2 translocations in leukemias of mature B cells

Although translocations of the BCL2 gene are frequent in B-cell non- Hodgkin's lymphomas (B-NHL) the incidence, nature, and prognostic significance of similar translocations in the phenotypically related chronic leukemias of mature B cells are unknown. Therefore, we examined 170 cases of B-cell chronic lymphocytic leukemia (B-CLL), 7 cases of B- cell prolymphocytic leukemia (B-PLL), 25 cases of hairy cell leukemia (HCL) and 22 cases of splenic lymphoma with villous lymphocytes (SLVL) with defined cytogenetic abnormalities by DNA blot using both 5' and 3' BCL2 probes to search for rearrangement of the BCL2 locus. Translocation t(14;18) (q32.3;q21.3) was detected cytogenetically in 3 cases of B-CLL. All had breakpoints in the 3' region of BCL2, mapping between the major breakpoint region (MBR) and the minor cluster region (mcr), the breakpoint clusters commonly detected in B-NHL. In 2 of the 3 cases, the breakpoint within BCL2 was mapped to a 1.0-kb EcoRI- HindIII fragment indicating a clustering of breakpoints. Two cases of B- CLL had cytogenetically detectable t(2;18)(p11;q21.3) or t(18;22)(q21.3;q11). Both had rearranged the 5' region of the BCL2 gene to the corresponding lg light-chain gene. Molecular cloning of the t(18;22)(q21.3;q11) showed that the translocation disrupted the BCL2 promoter region and the first untranslated BCL2 exon. Nevertheless, high levels of BCL2 protein were seen in this case. Only 2 other cases in whom cytogenetic analysis was not successful showed rearrangement of the 5' region of BCL2, an overall incidence of 2.3%. No cases of B-PLL, HCL, or SLVL showed either 5' or 3' BCL2 rearrangement. These data confirm the cytogenetic observations that translocations involving the BCL2 locus in all forms of leukemia of mature B cells are rare, and limited to a minor subset of B-CLL. BCL2 translocations in B-CLL involve hot spots of recombination of both the 5' and 3' regions of the BCL2 gene, which are distinct from those commonly seen in B-NHL, suggesting distinct pathogenic mechanisms.     

Neutrophil cathepsin G modulates the platelet surface expression of the glycoprotein (GP) Ib-IX complex by proteolysis of the von Willebrand factor binding site on GPIb alpha and by a cytoskeletal-mediated redistribution of the remainder of the complex

The effects of neutrophil cathepsin G on the glycoprotein (GP) Ib-IX complex of washed platelets were examined. Cathepsin G resulted in a concentration- and time-dependent decrease in the platelet surface GPIb- IX complex, as determined by flow cytometry, binding of exogenous von Willebrand factor (vWF) in the presence of ristocetin, and ristocetin- induced platelet agglutination. Cathepsin G resulted in proteolysis of the vWF binding site on GPIb alpha (defined by monoclonal antibody [MoAb] 6D1), as determined by increased supernatant glycocalicin fragment (a proteolytic product of GPIb alpha); decreased total platelet content of GPIb; and lack of effect of either cytochalasin B (an inhibitor of actin polymerization), prostaglandin I2 (an inhibitor of platelet activation), or prior fixation of the platelets. However, cathepsin G resulted in minimal decreases in the binding to fixed platelets of MoAbs TM60 (directed against the thrombin binding site on GPIb alpha) and WM23 (directed against the macroglycopeptide portion of GPIb alpha). In contrast to its proteolytic effect on GPIb alpha, the cathepsin G-induced decrease in platelet surface GPIX and the remnant of the GPIb-IX complex (defined by MoAbs FMC25 and AK1) was via a cytoskeletal-mediated redistribution, as determined by lack of change in the total platelet content of GPIX and the GPIb-IX complex; complete inhibition by cytochalasin B, prostaglandin I2, and prior fixation of platelets. Experiments with Serratia protease-treated and Bernard- Soulier platelets showed that neither platelet surface GPIb nor cathepsin G-induced proteolysis of GPIb were required for the cathepsin G-induced redistribution of the remnant of the GPIb-IX complex or the cathepsin G-induced increase in platelet surface P-selectin. In summary, neutrophil cathepsin G modulates the platelet surface expression of the GPIb-IX complex both by proteolysis of the vWF binding site on GPIb alpha and by a cytoskeletal-mediated redistribution of the remainder of the complex. Prior studies show that, although thrombospondin 1, antiserine proteases, and plasma are all inhibitors of cathepsin G, the effects of cathepsin G on platelets, including an increase in surface GPIIb-IIIa, occur during close contact between neutrophils and platelets in a protective microenvironment (eg, thrombosis and local inflammation).(ABSTRACT TRUNCATED AT 400 WORDS)     

Cardiovascular mortality and heart failure risk score for patients after ST-segment elevation acute myocardial infarction treated with primary percutaneous coronary intervention (Data from the Leiden MISSION! Infarct Registry)

The risk scores developed for the prediction of an adverse outcome in patients after ST-segment elevation myocardial infarction (STEMI) have mostly addressed patients treated with thrombolysis and evaluated solely all-cause mortality as the primary end point. Primary percutaneous coronary intervention in patients with STEMI has improved the outcome significantly and might have changed the relative contribution of different risk factors. Our patient population included 1,484 consecutive patients admitted with STEMI who had undergone primary percutaneous coronary intervention. The clinical, angiographic, and echocardiographic data obtained during hospitalization were used to derive a risk score for the prediction of short-term (30-day) and long-term (1- and 4-year) cardiovascular mortality and hospitalization for heart failure. During a median follow-up of 30 months, 87 patients (6%) died from cardiovascular mortality or were hospitalized for heart failure. Multivariate Cox regression analyses identified age ≥70 years, Killip class ≥2, diabetes, left anterior descending coronary artery as the culprit vessel, 3-vessel disease, peak cardiac troponin T level ≥3.5 μg/L, left ventricular ejection fraction ≤40%, and heart rate at discharge ≥70 beats/min as relevant factors for the construction of the risk score. The discriminatory power of the model as assessed using the areas under the receiver operating characteristic curves was good (0.84, 0.83, and 0.81 at 30 days and 1 and 4 years, respectively), and the patients could be allocated to low-, intermediate-, or high-risk categories with an event rate of 1%, 6%, and 24%, respectively. In conclusion, the current risk model demonstrates for the first time that 8 parameters readily available during the hospitalization of patients with STEMI treated with primary percutaneous coronary intervention can accurately stratify patients at long-term follow-up (≤4 years after the index infarction) into low-, intermediate-, and high-risk categories.