マツノザイセンチュウ，Bursaphelenchus xylophilusに随伴する松萎凋性細菌の単離とその毒性代謝物質

Based on the observation that ray parenchyma cell death took place prior to nematode population increase in pine wood,the authors suspected that any microorganisms carried by pathogenic nematodes would be involvedin the pathogenic process.The authors screened pathogenic nematode-accompanying microbes for their toxicity against cultured cells of Pinus thunbergiis and isolated and identified 3 toxic strains,Bacillus cereus HY-3,B.subtilis HY-16,and Bmegaterium HY-17 , whose toxic products were identified as phenylacertic acid.Inoculation of pine seedlings with the toxic bacterium alone did not cause the seedling to wilt , but inoculation of pine seedlings with the toxic bacterium carried by weakly pathogenic nematodes wilted the seedling as much as strongly pathogenic nematodes . These results suggested that phenyllacetic acid-producing bacteria could invade pine trees by accompanying pine wood nematodes , and produce phenylacetic acid , a toxic metabolite , in the wood.マツ材線虫病の初期症状である樹脂道エピセリウム細胞や周辺柔細胞の変性は、マツノザイセンチュウのその場への到着および増殖に先行して起こることから、マツノザイセンチュウに随伴する微生物が発病に関与しているのだはないかと推論し、本研究では、クロマツ培養細胞に対する毒性を指標にして強病原生マツノザイセンチュウから毒物質生産細菌を数株を単離したえ。さらに、この毒性代謝物質を単離し、フェニル酢酸と同定した。フェニル酢酸生産細菌は、普遍的に存在するが、フェニル酢酸生産性には、大きい差があることを確認した。このフェニル酢酸生産細菌のみを接種しても、アカマツ実生は萎凋しなかったが、弱病原性マツノザイセンチュウに保持されて接種すると、ザイセンチュウの病原性が強くなった。このかとから、フェニル酢酸生産細菌は、マツノザイセンチュウに運搬されて松樹体内を移動し病原毒素フェニル酢酸を生産するものと推論した

The Impact of KRAS Mutation in Patients With Sporadic Nonampullary Duodenal Epithelial Tumors

INTRODUCTION: The genomic characterization of primary nonampullary duodenal adenocarcinoma indicates a genetic resemblance to gastric and colorectal cancers. However, a correlation between the clinical and molecular characteristics of these cancers has not been established. This study aimed to elucidate the clinicopathological features of sporadic nonampullary duodenal epithelial tumors, including their molecular characteristics and prognostic factors. METHODS: One hundred forty-eight patients with sporadic nonampullary duodenal epithelial tumors were examined in this study. Patient sex, age, TNM stage, tumor location, treatment methods, histology, KRAS mutation, BRAF mutation, Fusobacterium nucleatum, mucin phenotype, and programmed death-ligand 1 (PD-L1) status were evaluated. KRAS and BRAF mutations, Fusobacterium nucleatum, mucin phenotype, and PD-L1 status were analyzed by direct sequencing, quantitative polymerase chain reaction, and immunochemical staining. RESULTS: The median follow-up duration was 119.4 months. There were no deaths from duodenal adenoma (the primary disease). Kaplan-Meier analysis for duodenal adenocarcinoma showed a significant effect of TNM stage (P DISCUSSION: Only KRAS mutation was a significant prognostic factor in primary sporadic nonampullary duodenal adenocarcinoma in cases in which TNM stage was considered

Pathological Investigation of Congenital Bicuspid Aortic Valve Stenosis, Compared with Atherosclerotic Tricuspid Aortic Valve Stenosis and Congenital Bicuspid Aortic Valve Regurgitation

Congenital bicuspid aortic valve (CBAV) is the main cause of aortic stenosis (AS) in young adults. However, the histopathological features of AS in patients with CBAV have not been fully investigated.We examined specimens of aortic valve leaflets obtained from patients who had undergone aortic valve re/placement at our institution for severe AS with CBAV (n = 24, CBAV-AS group), severe AS with tricuspid aortic valve (n = 24, TAV-AS group), and severe aortic regurgitation (AR) with CBAV (n = 24, CBAV-AR group). We compared the histopathological features among the three groups. Pathological features were classified using semi-quantitative methods (graded on a scale 0 to 3) by experienced pathologists without knowledge of the patients' backgrounds. The severity of inflammation, neovascularization, and calcium and cholesterol deposition did not differ between the CBAV-AS and TAV-AS groups, and these four parameters were less marked in the CBAV-AR group than in the CBAV-AS (all p<0.01). Meanwhile, the grade of valvular fibrosis was greater in the CBAV-AS group, compared with the TAV-AS and CBAV-AR groups (both p<0.01). In AS patients, thickness of fibrotic lesions was greater on the aortic side than on the ventricular side (both p<0.01). Meanwhile, thickness of fibrotic lesions was comparable between the aortic and ventricular sides in CBAV-AR patients (p = 0.35).Valvular fibrosis, especially on the aortic side, was greater in patients with CBAV-AS than in those without, suggesting a difference in the pathogenesis of AS between CBAV and TAV