Leiomyosarcoma of the Right Atrium Masked by a Covering Thrombus: Conflicting Results of Echocardiography and Transvenous Biopsy—In Favor of Echocardiography

A 62-year-old woman was admitted for the evaluation of pedal edema and ascitis. Echocardiography revealed a right atrial (RA) mass invading the interatrial septum and extending into the inferior vena cava (IVC). Contrast enhanced computerized tomography scan excluded extravascular involvement. An organized thrombus was diagnosed by transvenous endomyocardial biopsy. The patient was treated with continuous intravenous heparin, and died soon after from hepatic failure. Postmortem histologic examination revealed a leiomyosarcoma surrounded by a thrombus involving RA, IVC, and hepatic veins. Endomyocardial biopsy played a misleading role that affected patient's management.     

Comparative immunohistochemical study on the expression of αB crystallin, ubiquitin and stress-response protein 27 in ballooned neurons in various disorders

This report deals with a comparative study on the expression of alpha B crystallin, ubiquitin, stress-response protein 27 (srp 27), srp 72 and phosphorylated neurofilament protein (pNFP) by ballooned neurons in Pick's disease, Creutzfeldt-Jakob disease (CJD), amyotrophic lateral sclerosis (ALS), leptomeningeal carcinomatosis, anterior spinal artery syndrome and pellagra. Immunohistochemical techniques were used. alpha B Crystallin was expressed by the majority of ballooned neurons of Pick's disease and CJD, but not by those of the other disorders. Ubiquitin and srp 27 expression was also restricted to abnormal neurons of Pick's disease and CJD, but the proportion of stained cells was less than that expressing alpha B-crystallin. There was no evidence of ballooned neurons expressing srp 72. Except for those of pellagra patients, phosphorylated neurofilament protein (pNFP) was detected in most abnormal neurons. Our results suggest that the mechanisms involved in formation and maintenance of swollen neurons in Pick's disease and CJD may be different than those of ballooned neurons in the other entities studied.     

Mapping of Antigenic Determinants of Purified, Lipid-Free Human Serum Amyloid A Proteins

Serum amyloid A (SAA) is the major apolipoprotein of high-density lipoproteins (HDL) present during the acute-phase reaction. To map specific epitopes on purified, lipid-free SAA, sequence-specific antibodies raised against synthetic peptides corresponding to amino acid residues 1–17, 14–30, 27–44, 40–63, 59–72, 68–84, 79–94 and 89–104 of human SAA₁ were studied. Using the indirect sandwich dissociation-enhanced lanthanide fluorescence immunoassay, antibodies raised against epitopes comprising residues 1–17, 14–30, 40–63 and 79–94 failed to recognize the corresponding domains on isolated human SAA₁/SAA₂ or a mixture of both isoforms, indicating that these epitopes are masked, apparently because of specific folding and/or self-aggregation (dimerization). The accessible antigenic determinants of isolated SAA are epitopes comprising residues 31–39, 64–78 and 95–104. The present findings indicate that: (i) the same epitopes are exposed, irrespective whether SAA is HDL-associated or in its lipid-free form and that (ii) monomeric and dimeric SAA co-exist to a similar extent in the lipid-free form, irrespective of whether conditions are non-denaturating, denaturating, acidic or basic. From our studies it is proposed that isolated, purified SAA may serve as a reliable standard for quantification of HDL-associated SAA and for mimicking the interaction of acute-phase HDL particles with peripheral tissues in vitro .     

ST segment depression in lateral limb leads in inferior wall acute myocardial infarction: Implications regarding the culprit artery and the site of obstruction

We examined whether the pattern of ST segment depression inlateral leads (I, aVL, V5, V6) in the initial electrocardiogramof patients (n=88) with inferior wall acute myocardial infarction(ST segment elevation of 1 mm in 2 inferior leads) correlateswith the site of obstruction, as determined angiographicallyduring acute hospitalization. Of the 62 patients in which the culprit artery could be determinedunequivocally, in 46 the culprit artery was the right coronaryartery (20 proximal to the first right ventricular branch and26 distal), and in 16 the left circumflex coronary artery (sevenproximal to the first marginal branch or involving a high firstmarginal branch, and nine with distal obstruction). SignificantST segment depression (ST1 mm) in leads I and aVL was more commonin right coronary artery obstruction (P<0.05 and P<0.0001,respectively). The absence of significant ST segment depressionin lead a VL was most common in proximal circumflex obstruction(P<0.0001), with a similar trend for lead I (P<0.11).ST segment depression patterns in leads V₅ and V₆ were not indicativeof the infarct-related artery or the site of obstruction. Thus,significant ST segment depression in leads I and aVL indicatesright coronary artery-associated inferior wall acute myocardialinfarction with a sensitivity of 70% and 100%, and a specificityof 63% and 38%, respectively, whereas the lack of ST segmentdepression in these leads indicates proximal circumflex obstructionwith a sensitivity of 71% and 86%, and a specificity of 65%and 100%, respectively.