Genome-wide cDNA microarray analysis of gene expression profiles in pancreatic cancers using populations of tumor cells and normal ductal epithelial cells selected for purity by laser microdissection

To characterize molecular mechanism involved in pancreatic carcinogenesis, we analysed gene-expression profiles of 18 pancreatic tumors using a cDNA microarray representing 23,040 genes. As pancreatic ductal adenocarcinomas usually contain a low proportion of cancer cells in the tumor mass, we prepared 95% pure populations of pancreatic cancer cells by means of laser microbeam microdissection, and compared their expression profiles to those of similarly purified, normal pancreatic ductal cells. We identified 260 genes that were commonly upregulated and 346 genes that were downregulated in pancreatic cancer cells. Because of the high degree of purity in the cell populations, a large proportion of genes that we detected as upregulated or downregulated in pancreatic cancers were different from those reported in previous studies. Comparison of clinicopathological parameters with the expression profiles indicated that altered expression of 76 genes was associated with lymph-node metastasis and that of 168 genes with liver metastasis. In addition, expression levels of 30 genes were related to the recurrence of disease. These genome-wide expression profiles should provide useful information for finding candidate genes whose products might serve as specific tumor markers and/or as molecular targets for treatment of patients with pancreatic cancer.     

Regulation of caspase-6 and FLIP by the AMPK family member ARK5

Colorectal cancer cells are unique in that they escape Fas-mediated cell death in the presence of Fas ligand, and we recently reported that AMP-activated protein kinase-related kinase 5 (ARK5) suppresses cell death signaling mediated by cell death receptor in Akt-dependent manner. In the current study, therefore, we examined whether ARK5 is involved in the escape from Fas-mediated cell death of colorectal cancer cells. Among 10 cell lines, ARK5 mRNA expression was observed in LoVo, SW480, and SW1116 cell lines. Interestingly, SW480 and SW1116 cell lines, but not LoVo cell line, showed expressions of both Fas ligand (FasL) and Fas mRNAs. SW620 cell line also showed FasL mRNA; however, Fas and ARK5 mRNAs were not detected. Furthermore, well-coincided expression among ARK5, FasL, and Fas mRNAs was observed in tumor tissues from patients with colorectal cancer, suggesting the suppression of FasL/Fas system-induced cell death by ARK5 in colorectal cancer cell lines. Intensive cell death, which was dependent on the FasL/Fas system was encountered when ARK5 antisense RNA (ARK5/AS) was introduced into SW480 cells. FLIP was expressed in only ARK5 mRNA-expressing cell lines, and ARK5/AS induced FLIP cleavage in a caspase-6-dependent manner. Amino-acid sequence analysis of caspase-6 revealed two putative sites of phosphorylation by ARK5 at Ser80 and Ser257. Although active caspase-6 overexpression induced cell death in SW480 and DLD-1 cell lines, SW480 cells, but not DLD-1 cells, exhibited strong resistance to procaspase-6 overexpression. Moreover, mutant caspase-6, in which the Ser257 was substituted by Ala (caspase-6/SA), induced cell death and FLIP degradation, even in SW480 cells. Active ARK5 was found to phosphorylate wild-type caspase-6 in vitro, but not caspase-6/SA, and the prevented activation of caspase-6 was promoted due to its phosphorylation by active ARK5 in vitro. On the basis of the results of this study, we propose that ARK5 negatively regulates procaspase-6 by phosphorylation at Ser257, leading to resistance to the FasL/Fas system.     

Successful treatment of diffuse large B-cell lymphoma following Waldenström's macroglobulinemia with CHOP chemotherapy followed by combination therapy of CHOP with rituximab

We report a 72-year-old man with Waldenstr?m's macroglobulinemia (WM) in whom diffuse large B-cell lymphoma (DLCL) occurred 17 years after the diagnosis of WM. The malignant cells of both DLCL and WM expressed CD20 on their surface. CHOP plus anti-CD20 monoclonal antibody, rituximab, were effective for both diseases, and the patient remains disease-free 17 months later.     

Ganglioside complexes as new target antigens in Guillain-Barré syndrome

Antibodies specific for a complex of gangliosides GD1a and GD1b (GD1a/GD1b) were found in sera from eight of 100 patients with Guillain-Barre syndrome (GBS) by the use of enzyme-linked immunosorbent assay and thin-layer chromatogram immunostaining. Those sera also had antibody activities to such ganglioside complexes as GD1a/GM1, GD1b/GT1b, and GM1/GT1b but had little or no reactivity to the each isolated antigen. Clustered epitopes of the ganglioside complex in the plasma membrane may be targeted by such an antibody, and interaction between the antibody and ganglioside complex may induce the neuropathy.     

Propagation of tonic posturing in supplementary motor area (SMA) seizures

We analyzed ictal motor symptoms in 10 patients diagnosed to have supplementary motor area (SMA) seizures based on ictal encephalographic (EEG) findings and ictal clinical semiology. Inclusion criteria were (1) EEG seizure pattern in the vertex for the scalp recording or in the area over and/or adjacent to SMA for epicortical recording and (2) ictal motor semiology characterized, as previously reported, by sudden and a brief tonic posturing of extremities and trunk mainly occurring during sleep without loss of consciousness. In 50% (5/10) of the patients, tonic posturing began in one part of the body and moved to other part(s) in 5-10s. Unlike Jacksonian march seen in seizures involving the primary sensorimotor area (S1-M1), it spread in no accordance with the somatotopy in S1-M1. The sequential propagation of tonic posturing may represent the somatotopic organization within the SMA proper.     

Stimulus duration in working memory is represented by neuronal activity in the monkey prefrontal cortex

Humans are capable of memorizing several attributes of a presented stimulus as well as its duration of presentation. However, the neuronal representation of stimulus duration in memory remains unknown. This study investigated activities of single neurons in the prefrontal cortex of monkeys while they were performing a behavioral task in which working memory for stimulus duration was needed. Here we describe specific neurons whose discharge rates reflect encoding or retention of the duration of the presentation of stimuli to be remembered. We also describe other specific neurons whose activities reflect encoding or retention of fixed duration, similar but unrelated to the stimulus duration presented in each trial. Some of these specific neurons showed the same duration-related discharges even while the monkeys were performing a different task, in which working memory for stimulus duration was no longer needed. From these results, we suggest that neurons in the prefrontal cortex play roles in encoding and retention of temporal information in working memory and that some of those neurons are dedicated to representation of temporal information attributed to stimuli even when the temporal information is unnecessary for correct performance.     

Percutaneous radiofrequency ablation for unresectable large hepatic tumours during hepatic blood flow occlusion in four patients

AIM: To evaluate percutaneous radiofrequency (RF) ablation therapy for unresectable large hepatic tumours combined with regional interruption of hepatic blood flow, and to assess the safety and efficacy of this procedure. MATERIALS AND METHODS: Four patients with hepatic tumours were enrolled in this study. Patients were treated by a single session of RF ablation during occlusion of both hepatic artery and hepatic vein. Tumour size ranged from 45-57 mm (mean 50.2 mm). Initial therapeutic efficacy was evaluated with helical computed tomography (CT) performed within 9 days after the treatment. CT or magnetic resonance imaging (MRI) was performed every 2-3 months thereafter. RESULTS: The largest axis of coagulated lesions after the ablation was 50-60 mm (mean 56.5 mm) in diameter. The ablation therapy was considered complete in three patients; after a mean follow-up of 12.7 months, CT and MRI revealed complete destruction of their tumours. One patient required further treatment. No severe complications occurred. CONCLUSION: Although further studies are needed, in this limited clinical trial a local ablation area exceeding 50 mm in diameter was achieved safely.