Chronic Volume Overload Caused by Abdominal Aorto-Venocaval Shunt Provides Arrhythmogenic Substrates in the Rat Atrium.

Atrial enlargement is thought to provide arrhythmogenic substrates, leading to the induction of atrial fibrillation (AF). In this study, we investigated the anatomical, molecular biological, and electrophysiological characteristics of remodeled atria in an animal model with chronic volume overload. We used rats that underwent abdominal aorto-venocaval shunt (AVS) surgery. In the in vivo studies, marked changes in electrocardiogram parameters, such as the P-wave duration, PR interval, and QRS width, as well as prolongation of the atrial effective refractory period were observed 12 weeks after the creation of AVS (AVS-12W), which were undetected at 8 weeks postoperative (AVS-8W) despite obvious atrial and ventricular enlargement. Moreover, the duration of AF induced by burst pacing in the AVS-12W rats was significantly longer than that in the Sham and AVS-8W rats. In the isolated atria, a longer action potential duration at 90% repolarization was detected in the AVS-12W rats compared with that in the Sham group. The mRNA levels of the Kv and Kir channels in the right atrium were mostly upregulated in the AVS-8W rats but were downregulated in the AVS-12W rats. These results show that chronic volume overload caused by abdominal AVS provides arrhythmogenic substrates in the rat atrium. The difference in gene expression in the right atrium between the AVS-8W and AVS-12W rats may partly explain the acquisition of arrhythmogenicity.

Characterization of de novo diffuse large B-cell lymphoma with a translocation of c-myc and immunoglobulin genes.

The characteristics of de novo diffuse large B-cell lymphoma (DLBCL) with translocation of c-myc and immunoglobulin (Ig) genes (c-myc/Ig DLBCL), were investigated in 13 cases of c-myc/Ig DLBCL. Immunohistochemistry revealed five cases were positive for CD10 and BCL6 expression (CD10(+)/BCL6(+)), five cases of CD10(-)/BCL6(+)/MUM1(-), one case of CD10(-)/BCL6(+)/MUM1(+) and two cases of CD10(-)/BCL6(-)/MUM1(+) expression, indicating 10 cases of germinal center B-cell DLBCL and three cases of non-germinal center B-cell DLBCL. Ongoing mutation of the Ig heavy chain gene variable region (IgH-V) was found in two cases with CD10 and BCL6 expression and one case showing CD10(-)/BCL6(+)/MUM1(-) expression. These three cases of ongoing mutation of the IgH-V gene did not express BCL2, unlike those without ongoing mutation. These results suggest a heterogeneous immunophenotype and genotype for c-myc/Ig DLBCL, with CD10(-)/BCL6(+)/MUM1(-) cases the most frequent.

Primary rhabdomyosarcoma of the sacrum: a case report and review of the literature.

We describe herein a rare case of primary rhabdomyosarcoma (RMS) occurring in the sacrum. A 16-year-old woman presented with a 2-month history of pain in bilateral buttocks and posterior thighs. Computed tomography showed a primary tumor with bone destruction in the 2nd sacral vertebra and invasion to the 1st to 3rd vertebrae and retroperitoneal space. Histological examination of the tumor showed proliferation of spindle-shaped cells intermingled with rhabdomyoblasts in a fascicular and storiform growth pattern. Tumor cells showed immunoreactivity for vimentin, desmin, muscle-specific actin, sarcomeric actin, alpha-smooth muscle actin and CD99, and partial immunoreactivity for myoD1, myf-4, myogenin and myoglobin. Reverse transcription polymerase chain reaction demonstrated expression of myoD1. On the basis of the aforementioned findings, a poorly differentiated spindle cell variant of embryonal RMS was diagnosed. The patient underwent combined therapy with chemotherapy and radiotherapy, but died 17 months after incisional biopsy. The present case is instructive in differential diagnosis of primary bone tumors, and the possibility of skeletal RMS needs to be considered.

CD5+ diffuse large B-cell lymphoma consists of germline cases and hypermutated cases in the immunoglobulin heavy chain gene variable region.

CD5+ diffuse large B-cell lymphoma (DLBCL) has recently been identified as a subgroup with different clinical characteristics from CD5- DLBCL and as having a poorer outcome than CD5- DLBCL. Data regarding differences in gene alteration between CD5+ and CD5- DLBCL have accumulated. In this article, we report an analysis of the immunoglobulin heavy-chain gene variable region (VH) gene in 35 cases of CD5+ DLBCL and compare these cases with those with the germline of the VH gene (GL-VH) and those with a somatically hypermutated VH gene (HM-VH). When the CD5+ DLBCL cases were subdivided with a cutoff value of 98% homology in the VH gene, there were 7 cases (20%) of GL-VH and 28 cases (80%) of HM-VH. The proportion of GL-VH cases in CD5+ DLBCL was more than that in CD5 DLBCL. Although we found no significant difference in pretreatment clinical parameters between the GL-VH and HM-VH subgroups, there was a tendency for the GL-VH subgroup to show lower incidences of elevation of lactate dehydrogenase and >1 site of extranodal involvement compared to the HM-VH subgroup. The overall survival curve of the HM-VH subgroup showed a rapid decline followed by a plateau, whereas that of the GL-VH subgroup declined constantly after 5 years, suggesting that GL-VH disease may not be curable by standard therapies. These findings suggest that CD5+ DLBCL with GL-VH shares clinical features with mantle cell lymphoma, the cellular origin of which has been considered to be pre-germinal center B-cells. We therefore propose that analysis of the VH gene is important for predicting the clinical course of CD5+ DLBCL.

Epstein-Barr virus-positive Hodgkin/Reed-Sternberg-like B cell in non-hodgkin lymphoma: nucleotide sequence of the amplified immunoglobulin heavy-chain variable region gene by the single-cell polymerase chain reaction technique.

We examined nucleotide sequences of Epstein-Barr virus (EBV)-positive Hodgkin/Reed-Sternberg (HRS)-like B cells in a case of diffuse large B-cell lymphoma (DLBCL) and a case of adult T-cell lymphoma (ATL) for single-cell polymerase chain reaction of the immunoglobulin heavy-chain gene variable region (VH gene). HRS-like B cells were scattered in the area irrelevant to the lymphoma infiltrates of DLBCL and in the lymphoma area of ATL. HRS-like B cells were positive for CD20 and CD30 but negative for CD15. EBV presented in HRS-like B cells in both cases but not in any lymphoma cells. VH genes of five HRS-like B cells analyzed in DLBCL were polyclonal and showed in-frame sequences with 0% to 2.8% somatic mutation frequency. In an ATL, VH genes of five HRS-like B cells analyzed were polyclonal and somatically mutated. Four cells carried in-frame rearrangements with 3.5% to 17.7% mutation frequency. One of the VH genes has a one-codon deletion. From the fifth cell, an out-of-frame rearrangement with an insertion and a deletion was obtained. Thus, we showed polyclonal EBV-positive HRS-like B cells in both DLBCL and ATL and that whereas EBV-positive, HRS-like B cells in DLBCL exhibited unmutated and mutated VH gene, those in ATL were found to have a somatically mutated VH gene with/without deletions and/or insertions. The HRS-like B cells may appear because of active EBV infection in a patient who is immunosuppressed from the primary lymphoma.

The evaluation of the biological behavior and grade among cases with mantle cell lymphoma.

We have studied the expression of MIB-1 and prognosis in cyclin D1(CyD1)+ and CyD1- mantle cell lymphoma (MCL), and compared them to B-CLL/SLL. All cases were assigned to four groups by immunoreactivity and primary sites: (1) CyD1+ nodal MCL, 11 cases: (2) CyD1+ extranodal MCL (multiple lymphomatous polyposis, (MLP)) three cases: (3) CyD1- nodal MCL, three cases: and (4) CyD1- B-CLL/SLL, seven cases. The average of MIB-1 labeling indexes of the four groups were 30.66, 8.70, 9.30 and 4.66, respectively. The CyD1- group consisting of nodal MCL and CLL/SLL had a significantly longer median survival time (69 months) than the CyD1+ group consisting of nodal MCL and MLP (22 months, P = 0.01). These data indicate that CyD1- nodal MCL may show a lower MIB-1 labeling index, and has a better prognosis, than CyD1+ nodal MCL. In addition, a large difference in the average of MIB-1 labeling indexes between nodal MCL and MLP in the CyD1+ group was found.