Biomedical subjects

K I Ueno

Publications and source records attributed to K I Ueno.

3 recordsLinked to original sources

PubMed2001

Multicentric occurrence of esophageal cancer after gastrectomy: a preliminary report.

The effect of gastrectomy on the subsequent development of esophageal cancer was investigated, focusing on its multicentric occurrence. We retrospectively evaluated 28 patients who underwent subtotal esophagectomy for intrathoracic esophageal cancer between 1985 and 1999. They were divided into two groups according to whether or not they had previously undergone a gastrectomy: group 1, comprising 7 patients who had undergone gastrectomy and group 2, comprising 21 patients who had not. Clinical profiles of the patients were obtained from the medical records and the whole resected esophagus was histopathologically examined. The interval between gastrectomy and esophagectomy in group 1 was significantly shorter in the patients who had undergone gastrectomy for gastric cancer than in those who had undergone gastrectomy for a peptic ulcer, and also in the patients for whom anastomosis had been performed by Billroth I compared with Billroth II. The patients in group 1 were significantly younger than those in group 2. The multiple occurrence of esophageal cancer was found in 4 of 5 patients (80%) in group 1, and in 2 of 18 patients (11%) in group 2, with significantly higher frequency being seen in group 1. More than two coexisting cancer lesions apart from the primary tumor were detected in all four patients. Histological examination of all the coexisting cancer lesions showed well-differentiated squamous cell carcinoma confined within the superficial mucosal layer. No significant differences were noted in the location of the coexisting lesions between the oral and anal side of the primary tumors. Squamous dysplasia was randomly observed, especially around the cancer lesions. These findings suggest that gastrectomy precipitated subsequent chronic gastroesophageal reflux which in turn induced the development of squamous dysplasia and carcinoma at multiple locations in the esophagus.

Aged↗

PubMed2001

Aminoguanidine prevented the impairment of learning behavior and hippocampal long-term potentiation following transient cerebral ischemia.

The present study was performed to investigate whether increases in nitric oxide (NO) production via inducible nitric oxide synthase (iNOS) were involved in impairment of learning behavior and hippocampal long-term potentiation (LTP) following transient ischemia. Rats with four-vessel occlusion (4-VO) were used as an ischemic model. One week after permanent occlusion of the vertebral arteries, the common carotid arteries were clamped for 10 min under halothane anesthesia. Aminoguanidine (10 mg/kg i.p.), a relatively selective iNOS inhibitor, or saline was administered 30 min before common carotid arteries occlusion, and every 24-h for 4 days. We investigated whether hippocampal NO production was increased by ischemic insult using microdialysis on days 1, 4 and 7 after 4-VO. On days 1 and 4 after 4-VO, increases in NO production were observed, and this effect was inhibited by aminoguanidine. Four days after 4-VO, rats were subjected to the Y-maze test and contextual fear conditioning. Ischemic insults impaired learning behavior, and aminoguanidine ameliorated the impairment induced by 4-VO. Four days after 4-VO, the changes in the population spike amplitude were recorded as an index of LTP in Schaffer collateral-CA1 (carotid artery 1), the mossy fiber-CA3 and the perforant path-dentate gyrus synapses. LTP was significantly inhibited by 4-VO, except in mossy fiber-CA3 synapses. Pretreatment with aminoguanidine prevented the reduction of LTP in perforant path-dentate gyrus, but not in Schaffer collateral-CA1 synapses. These results suggest that post-ischemic increase in NO production via iNOS impaired the learning behavior. There is an association between behavioral performance and LTP formation in perforant path-dentate gyrus synapses, but neither in Schaffer collateral-CA1 nor in mossy fiber-CA3 synapses.

Animals↗

PubMed2001

New rat model for attention deficit hyperactive disorder (ADHD).

PURPOSE: In a strain of the Long-Evans Cinnamon (LEC) rats, we found spontaneously hyperactive animals designated as "wiggling," and established a congenic wiggling (Wig) rat by transferring the gene from the LEC to the Wistar King-Aptekman/Hokkaido (WKAH) strain. We evaluated the feasibility of the Wig rat for an animal model of human attention deficit hyperactive disorder (ADHD). METHODS: Mode of inheritance was examined by use of linkage analyses. Motor activity, behavior, and working memory were assessed by use of electric digital counters, open field test, and Y-maze and water-maze tests. RESULTS: The abnormal behavior, including hyperactivity, was transmitted in autosomal recessive mode. Diurnal and nocturnal motor activity of 12- to 14-week-old Wig rats was markedly higher than that of controls, and this hyperactivity was more prominent during nighttime than daytime. Ambulation in the open-field test was significantly increased in Wig rats, but rearing was decreased in Wig rats, compared with controls. Results of the Y-maze tests indicated that spontaneous alternation behavior was significantly impaired in Wig rats, although there was no difference in the total arm entries. The water-maze test could not be performed because, when exposed to water, Wig rats panicked and almost drowned. CONCLUSIONS: Wig rats are hyperactive and have impaired working memory and impulsive behavior, as assessed by the motor activity and open-field tests and the Y-maze test, and these abnormalities are transmitted by a single gene with Mendelian pattern. Wig rats represent an excellent animal model of human ADHD.

Animals↗