A Rare Pancreatic Tumor with Adenomatoid Tumor-like Findings.

A 74-year-old woman was referred to our hospital for the evaluation of slightly elevated tumor marker levels. Computed tomography revealed a well-demarcated tumor, approximately 15 mm in diameter, in the pancreatic tail. Endoscopic ultrasound-guided fine-needle aspiration findings suggested poorly differentiated cancer. The tumor was surgically resected, but postoperative pathologic confirmation was not possible. After one year without treatment and no recurrence, an evaluation by a specialized facility was requested for a definitive diagnosis. Adenomatoid tumor was deemed most likely based on the histopathology and immunostaining findings; however, a definitive diagnosis was difficult because of atypical findings. The patient was recurrence-free for 36 months at the last follow-up.

Porphyromonas gingivalis induces the production of interleukin-31 by human mast cells, resulting in dysfunction of the gingival epithelial barrier.

Interleukin (IL)-31 is important for innate immunity in mucosal tissues and skin, and increased IL-31 expression participates in the pathogenesis of chronic inflammatory diseases affecting the skin, airways, lungs, and intestines. We investigated the contribution of mast cells to the induction of IL-31 production following infection with the periodontal pathogen, Porphyromonas gingivalis. We found that oral infection with P. gingivalis increased IL-31 expression in the gingival tissues of wild-type mice but not in those of mast cell-deficient mice. The P. gingivalis-induced IL-31 production by human mast cells occurred through the activation of the JNK and NF-κB signalling pathways and was dependent on the P. gingivalis lysine-specific protease gingipain-K. P. gingivalis infection induced IL-31 receptor α and oncostatin M receptor ß expression in human gingival epithelial cells. Notably, the P. gingivalis-induced IL-31 production by mast cells led to the downregulation of claudin-1, a tight junction molecule, in gingival epithelial cells, resulting in an IL-31-dependent increase in the paracellular permeability of the gingival epithelial barrier. These findings suggest that IL-31 produced by mast cells in response to P. gingivalis infection causes gingival epithelial barrier dysfunction, which may contribute to the chronic inflammation observed in periodontitis.

Pneumatosis intestinalis with a benign clinical course: a report of two cases.

BACKGROUND: Pneumatosis intestinalis (PI) is a rare condition characterized by the presence of gas within the gastrointestinal tract wall. Most cases of PI have a benign clinical course, although some have serious outcomes. Mechanical stress on or bacterial infection of the gastrointestinal tract wall may be responsible for the onset of PI, but the detailed mechanism of PI pathogenesis is still unclear. Here, we describe two Japanese patients presenting with benign PI. CASE PRESENTATION: Case 1, a 37-year-old previously healthy male patient, had a 1-week history of abdominal pain, and case 2, a 78-year-old female diabetic patient, had a 2-week history of voglibose treatment and abdominal pain. Intramural gas was mainly distributed in the colon in case 1 and in the small intestine in case 2. Interestingly, neither patient showed obvious inflammatory signs upon admission and recovered spontaneously with conservative treatment, including fasting and fluid infusion without antibiotics. Voglibose treatment was terminated in case 2. Recent studies have shown the presence of nonpathogenic bacteria, such as Clostridium spp., in PI lesions, which usually play an important role in modulating the tolerance of the gastrointestinal immune responses. The benign clinical course and spontaneous resolution of PI in these patients, without specific treatment, suggests that nonpathogenic indigenous bacteria in the gastrointestinal tract participate in the pathogenesis of PI. CONCLUSION: In patients with benign PI, the absence of an inflammatory response and the spontaneous resolution of the disease without specific treatment suggest the participation of nonpathogenic indigenous bacteria of the gastrointestinal tract.

Malignant Lymphoma in the Psoas Major Muscle.

An 84-year-old Japanese man taking warfarin to prevent cerebral infarction secondary to atrial fibrillation was admitted to our hospital for evaluation of a painless right back mass. Magnetic resonance imaging (MRI) showed an oval-shaped mass in the right psoas major muscle. The mass showed high intensity on T1-, T2-, and diffusion-weighted imaging and mimicked an acute-phase hematoma. However, it showed no chronological changes typical of a hematoma, and MRI revealed enlargement of the mass 1 week after admission. Histopathological examination of a biopsy specimen revealed diffuse large B-cell lymphoma (DLBCL). Although skeletal muscle lymphoma is rare, physicians should be familiar with its MRI characteristics. In addition, determination of the lymphoma subtype has important implications for the treatment of skeletal muscle lymphoma because DLCBL may have an especially poor prognosis.

Two patients with ruptured posterior inferior pancreaticoduodenal artery aneurysms associated with compression of the celiac axis by the median arcuate ligament.

Patients with compression of the celiac axis by the median arcuate ligament may develop aneurysms in the pancreaticoduodenal arcades. We experienced two cases of ruptured pancreaticoduodenal artery aneurysm associated with this condition. Both patients presented with abdominal pain and shock, and abdominal contrast-enhanced computed tomography showed retroperitoneal hematoma and compression of the celiac axis by the median arcuate ligament. Both patients were successfully treated by coil embolization. Patients with celiac axis compression or stenosis may develop recurrent aneurysms unless revascularization of the celiac axis is performed. Long-term follow-up is required because aneurysms may develop after 10 years or longer.

Purification and partial genome characterization of the bacterial endosymbiont Blattabacterium cuenoti from the fat bodies of cockroaches.

BACKGROUND: Symbiotic relationships between intracellular bacteria and eukaryotes are widespread in nature. Genome sequencing of the bacterial partner has provided a number of key insights into the basis of these symbioses. A challenging aspect of sequencing symbiont genomes is separating the bacteria from the host tissues. In the present study, we describe a simple method of endosymbiont purification from complex environment, using Blattabacterium cuenoti inhabiting in cockroaches as a model system. FINDINGS: B. cuenoti cells were successfully purified from the fat bodies of the cockroach Panesthia angustipennis by a combination of slow- and fast-speed centrifugal fractionations, nylon-membrane filtration, and centrifugation with Percoll solutions. We performed pulse-field electrophoresis, diagnostic PCR and random sequencing of the shoutgun library. These experiments confirmed minimal contamination of host and mitochondrial DNA. The genome size and the G+C content of B. cuenoti were inferred to be 650 kb and 32.1 +/- 7.6%, respectively. CONCLUSION: The present study showed successful purification and characterization of the genome of B. cuenoti. Our methodology should be applicable for future symbiont genome sequencing projects. An advantage of the present purification method is that each step is easily performed with ordinary microtubes and a microcentrifuge, and without DNase treatment.

Symbiotic "Archaezoa" of the primitive termite Mastotermes darwiniensis still play a role in cellulase production.

The relictual Mastotermes darwiniensis is one of the world's most destructive termites. Like all phylogenetically basal termites, it possesses protozoa in its hindgut, which are believed to help it digest wood. L. Li, J. Frohlich, P. Pfeiffer, and H. Konig (Eukaryot. Cell 2:1091-1098, 2003) recently cloned the genes encoding cellulases from the protozoa of M. darwiniensis; however, they claimed that these genes are essentially inactive, not contributing significantly to cellulose digestion. Instead, they suggested that the protozoa sequester enzymes produced by the termite in its salivary glands and use these to degrade cellulose in the hindgut. We tested this idea by performing gel filtration of enzymes in extracts of the hindgut, as well as in a combination of the salivary glands, foregut, and midgut. Three major cellulases were found in the hindgut, each of which had a larger molecular size than termite-derived salivary gland enzymes. N-terminal amino acid sequencing of one of the hindgut-derived enzymes showed that it was identical to the putative amino acid sequence of one mRNA sequence isolated by Li et al. (Eukaryot. Cell 2:1091-1098, 2003). The overall activity of the hindgut cellulases was found to be of approximately equal magnitude to the termite-derived cellulases detected in the mixture of salivary gland, foregut, and midguts. Based on these results, we conclude that, contrary to Li et al. (Eukaryot. Cell 2:1091-1098, 2003), the hindgut protozoan fauna of M. darwiniensis actively produce cellulases, which play an important role in cellulose digestion of the host termite.