Paraffin tissue block radiography: adjunct to breast specimen radiography

Radiography of specimens is an essential step in confirming excision of nonpalpable breast lesions. On occasion, however, the pathologist may not identify the lesion histologically. The authors report five cases in which suspicious microcalcifications were included in the excised tissue but were not identified by the pathologist. In all five, paraffin tissue block radiography enabled identification of the specific blocks containing the microcalcifications. The correct tissue blocks were then sectioned again, and the microcalcifications were identified histopathologically. In one case, the initial diagnosis of intraductal hyperplasia was changed to intraductal carcinoma with focal invasion. When the pathologist cannot identify the calcifications on initial histopathologic sections, this technique may assist in identification of the mammographic abnormality.     

Clonal relationship between lymphocytic predominance Hodgkin's disease and concurrent or subsequent large-cell lymphoma of B lineage

The occurrence of a large-cell lymphoma (LCL) concurrent with or subsequent to lymphocytic predominance Hodgkin's disease (LPHD) is well documented. Given the well-characterized B-cell nature of the Reed- Sternberg cell variants in LPHD, there may be a clonal relationship between the LPHD and the associated B-cell LCL. In this study, we adapted a highly sensitive, clonospecific assay to test whether the clone comprising the LCL exists in the corresponding LPHD tumor. Nine cases meeting the histologic criteria of nodular LPHD and B-cell LCL were identified, reviewed, and studied. Initially, clonality of both lesions was assessed using consensus primers to conserved regions in the IgH variable (frame-work III) and joining region genes in a polymerase chain reaction (PCR) assay. The PCR assay detected a clonal B-cell population in five of the LCLs, whereas analysis of eight cases of LPHD did not detect a dominant clone. Clonal products from the LCL were then sequenced, and clonospecific oligonucleotides were designed from the unique nucleotide sequence encoding the complementarity- determining region-III. These were then used as primers and/or probes in sensitive PCR-based assays on the corresponding LPHD tumors. In two cases, the clonospecific assay showed that the LPHD and LCL shared a common clone that was further confirmed by sequence analysis. This finding provides genotypic evidence that, at least in some cases, the LCL represents a clonal progression of LPHD.     

von Willebrand factor biosynthesis and partitioning between constitutive and regulated pathways of secretion after thrombin stimulation

The major part of von Willebrand factor (vWf) synthesized in cultured endothelial cells is secreted constitutively without stimulation and consists of all multimeric forms of vWf. In contrast, stimulation with secretagogues such as thrombin results in the release of vWf from the storage pool, the Weibel-Palade bodies which contain only the largest, most biologically potent multimeric forms of vWf. We wished to determine whether the signal for release of vWf might also function as a signal for replenishment of the vWf by enhancing de novo biosynthesis and if replenishment of the vWf storage pool involved a diversion of newly synthesized vWf from the constitutive pathway to the regulated pathway. vWf mRNA and protein levels in unstimulated human umbilical vein endothelial cells were compared with cells that were briefly stimulated with 1 U/mL thrombin for 15 minutes and then incubated without thrombin for periods up to 72 hours. A comparison was also made between unstimulated cells and cells continuously exposed to thrombin for up to 48 hours. Thrombin stimulation, brief or continuous, had no significant effect on subsequent biosynthesis of vWf protein or vWf- specific mRNA. Since thrombin releases vWf only from the storage pool, we examined the possibility of diversion of newly synthesized vWf from the constitutive pathway to the regulated pathway. Cells were pulse- labeled, incubated for 15 minutes with and without thrombin, chased for various periods in unlabeled media, and briefly restimulated with thrombin. No significant redistribution of vWf between the two pathways was observed as a result of thrombin stimulation for the time periods tested.(ABSTRACT TRUNCATED AT 250 WORDS)     

Amebic liver abscess: diagnosis and treatment evaluation with MR imaging

Magnetic resonance images were obtained before and after treatment in 17 patients with 29 amebic liver abscesses. Pretreatment T1-weighted images showed a sharply circumscribed, heterogeneous, low-signal-intensity mass, devoid of normal hepatic tissue and corresponding to the abscess cavity as measured sonographically. T2-weighted images showed the abscess cavity as a hyperintense region and also showed a larger region of hyperintensity extending from the cavity margins to the liver surface, corresponding to edematous but morphologically normal liver tissue. After treatment, the abscess cavity became homogeneously hypointense on T1-weighted images, corresponding to liquefaction of the abscess center. With successful treatment, concentric rings corresponding to (a) an inner margin of inflamed granulation tissue, (b) bands of type I collagen, and (c) the outer margin of atrophic and/or mildly inflamed liver tissue became prominent on T1- and T2-weighted images. T2-weighted images showed rapid resolution of the perifocal hepatic edema.