Biomedical subjects

Akira Okada

Publications and source records attributed to Akira Okada.

57 records · Page 4Linked to original sources

PubMedDate not supplied

Alanyl-glutamine-supplemented parenteral nutrition prevents intestinal ischemia-reperfusion injury in rats.

BACKGROUND: Intestinal ischemia-reperfusion (I/R) injury plays an important role in the pathogenesis of systemic inflammation and multiple-organ failure. We studied whether glutamine, the primary fuel of the small intestine, prevents intestinal mucosal damage after intestinal I/R in rats. METHODS: Rats were randomly divided into 4 groups: a sham-standard amino acid (SAA) group (n = 8); a sham-glutamine (Gln) group (n = 8); an I/R-SAA group (n = 10); and an I/R-Gln group (n = 9). Alanyl-glutamine solution was produced by replacing 36% of the total amino acid nitrogen with Gln. The superior mesenteric artery was ligated. After 60 minutes of ischemia, reperfusion was initiated and infusion was started. After 24-hour reperfusion, the intestinal segment was removed for morphological and biochemical analysis, and blood samples were drawn from the portal vein. Fluorescein isothiocyanate-conjugated dextran 70,000 (FITC-dextran) was infused into the duodenum 2 hours before animal death. RESULTS: In the I/R-SAA group, extensive epithelial sloughing and mucosal ulceration of villous tips were observed, whereas these findings did not occur in the I/R-Gln group. Mucosal wet weight, DNA, and protein content decreased significantly in the I/R-SAA group compared with the sham-SAA group and increased significantly in the I/R-Gln group compared with the I/R-SAA group. Plasma FITC-dextran significantly increased in the I/R-SAA group compared with the sham-SAA group, but the plasma level in the I/R-Gln group was comparable with that of each sham group. Mucosal glutaminase activity significantly increased in both the I/R-SAA and I/R-Gln groups compared with the sham-SAA and sham-Gln groups, respectively. CONCLUSIONS: Alanyl-glutamine protects against morphologic and functional mucosal injury after intestinal I/R in rats.

Animals↗

PubMedDate not supplied

Detection of a novel alteration of the Axin gene in various pediatric neoplasms.

The Wnt signaling pathway is conserved in various species from worms to mammals, and plays critical roles in development, cellular proliferation and differentiation. As part of Wnt signal transduction, the function of the Axin complex is inhibited, leading to the accumulation of beta-catenin protein. Axin gene mutations have been detected in several kinds of human cancers. In this study, we investigated Axin gene alterations in a series of 58 pediatric neoplasms including neuroblastomas, teratomas, rhabdomyosarcomas. Forty-eight non-tumor tissues were used as a control series to compare gene alterations and their frequencies between tumors and normal tissues. The whole coding region of the Axin gene was examined by PCR-SSCP method using 24 sets of the primers. Samples revealing aberrant band patterns were subjected to direct sequencing analysis. In total, we identified six variants in the exons and four intronic nucleotide substitutions in the tumor series. Similar sequence variants except a rare sequence variant at codon 98 (CCG right curved arrow CTG) were observed in the control series and these were regarded as non-pathogenetic polymorphisms. Our results indicated that a tumor-associated mutation of the Axin gene is generally a rare event in our series of pediatric neoplasms.

Axin Protein↗

PubMedDate not supplied

A modular laparoscopic training program for pediatric surgeons.

OBJECTIVES: A structured endoscopic training program for pediatric surgeons has not yet been established. This study was conducted to develop a modular training program (MTP) for pediatric surgeons and to evaluate its effectiveness for surgeons with and without previous experience in laparoscopic surgery. METHODS: Nine pediatric surgeons participated in the study. They were divided into 2 groups: group A (n=4), surgeons who had experienced more than 10 cases of laparoscopic surgery prior to MTP; group B (n=5), those who had experienced fewer than 10 cases. They participated in a standardized MTP workshop, which consisted of 2 "see-through" and 3 "laparoscopic" tasks. Each participant's psychomotor skills were evaluated objectively before and after MTP with a computer-generated virtual simulator and were evaluated for precision, efficiency, and speed. RESULTS: In participants, speed was significantly enhanced after MTP. In group A, no differences were observed after MTP, whereas significant improvements were noted in efficiency and speed after MTP in group B. Before MTP, efficiency was significantly higher in group A than in group B; however, no difference remained between the 2 groups after MTP. CONCLUSIONS: MTP is effective for nonlaparoscopic pediatric surgeons to become familiar with basic endoscopic skills.

Adult↗