Biomedical subjects
Publications and source records attributed to Kentaro Yamaguchi.
The fragmentation from beta-carboline-type monoterpenoid glucoindole alkaloids to harman, which is a hypothetical pathway to generate simple beta-carbolines, was actualized in the collision-induced dissociation in MS.
A novel inhibitor for anchorage-independent growth of tumor cells was isolated from the culture broth of a fungal strain. The producing strain TP-F0213 was identified as Penicillium aurantiogriseum Dierckx based on the taxonomic study. The compound designated anicequol was obtained by solvent extraction, HP-20 and silica gel chromatographies and recrystallization. The planar structure was elucidated by NMR analysis to be 16-acetoxy-3,7,11-trihydroxyergost-22-en-6-one. The absolute configuration was determined by the X-ray analysis of 3,7-bis-p-bromobenzoyl derivative. The carbon skeleton of anicequol has the same absolute configuration as ergostane and the configurations of substituents are 3beta, 5alpha, 7beta, 11beta, 16beta and 24S. Anicequol inhibited the anchorage-independent growth of human colon cancer DLD-1 cells with the IC50 of 1.2 microM whereas the IC50 against anchorage-dependent growth was 40 microM.
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1-beta-(4-Imidazoyl)- and 1-beta-(5-uracilyl)-1,4-dideoxy-1,4-imino-L-lyxitols were synthesized stereoselectively via a sequential procedure by the addition of the corresponding metal salts of heterocycles, Swern oxidation, reductive aminocyclization, and deprotection. Their structures were determined based on X-ray crystallography. From the NMR measurements of their N-acyl derivatives, two rotational isomers were observed. Their bioassay is also described.
The first example of a reagent-controlled enantioselective Pictet-Spengler reaction is demonstrated. Using diisopinocampheylchloroborane as a chiral Lewis acid catalyst, the Pictet-Spengler reaction of N(b)-hydroxytryptamine with aldehydes gave the corresponding 2-hydroxytetrahydro-beta-carbolines in up to 90% ee. The enantioselective Pictet-Spengler reaction catalyzed by chiral binaphthol-derived Brønsted acid-assisted Lewis acids, with up to 91% ee, is also demonstrated.
BACKGROUND/AIMS: We have performed endoscopic aspiration mucosectomy for early gastric cancer since June 1993. In order to increase the complete resection rate, it is necessary to place the cancer in the center of the resection field. To facilitate complete resection, a circular incision to guide aspiration mucosectomy was made with a cutting knife (pre-cutting) before endoscopic aspiration mucosectomy, a procedure that we call endoscopic aspiration mucosectomy, with pre-cutting. METHODOLOGY: Eleven patients who had undergone endoscopic aspiration mucosectomy with pre-cutting for early gastric cancer at our department were included in this study. All resected specimens were examined macroscopically and histopathologically to assess the curative potential of this modified method of mucosectomy. RESULTS: The resected specimens ranged from 22 to 28 mm (mean: 25 mm) in maximum diameter, while the tumors ranged from 10 to 18 mm (mean: 12 mm) in size. Each resected specimen had the tumor at its center. The resection rating was EA in 10 (90.9%) of the 11 lesions and EC in 1 lesion (9.1%). CONCLUSIONS: For curative endoscopic surgery, there is no dispute that complete resection is essential. Thus, endoscopic aspiration mucosectomy with pre-cutting should contribute to the cure of early gastric cancer.
Tumor growth and metastasis depend on angiogenesis, which is triggered by a chemical signal from the tumor cells to resting endothelial cells which then enter into a phase of rapid growth. Platelet Factor 4 (PF4) inhibits endothelial proliferation in vitro and angiogenesis in vivo. PF4 also inhibits tumor growth, however, as with other angiogenesis inhibitors, sustained tumor growth inhibition requires prolonged exposure to the recombinant protein. In this study, Lewis lung carcinoma (LLH) cells were transfected with the human PF4 via mammalian expression vectors and the ability of the transfected cells to form tumors and metastasis in vivo was evaluated. To evaluate the tumor growth rate of PF4-transfected (LLH/PF4) or control (LLH/neo) cells in vivo, we injected LLH/PF4 or LLH/neo cells subcutaneously (s.c.) or intravenously (i.v.). In the s.c. assay, LLH/PF4 had no significant effect on tumor growth. Conversely, in the i.v. assay, PF4 significantly reduced the number of lung metastasis (p=0.019) and weight (p=0.056). The inhibition of lung metastasis suggests that PF4 may inhibit tumor-associated neovascularization, and may prevent the affinity of tumor cells for the normal lung tissue.