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Featured researches published by Seishichi Yokoyama.


Journal of Pediatric Surgery | 1989

A study of the extracellular matrix protein as the migration pathway of neural crest cells in the gut: Analysis in human embryos with special reference to the pathogenesis of Hirschsprung's disease

Takao Fujimoto; Jun-ichi Hata; Seishichi Yokoyama; Toshio Mitomi

Immunocytochemical studies on the human embryo were made using antineuronal cell antibody and a panel of anti-extracellular matrix protein antibodies such as fibronectin, laminine, collagen type IV, and hyaluronic acid. All the enteric ganglia are shown to be from a single, vagal neural crest source, although the recent dual gradient migration theory of neural-crest-derived cells in the gut can be challenged. Neural-crest-derived cells first appear in the mesenchyme of the developing esophagus at 4 weeks, and then migrate down along the gut in a craniocaudal direction. The observed distribution of fibronectin and hyaluronic acid indicates the presence of these matrices providing a migration pathway for neural-crest-derived cells in the developing gut. The appearance of neural-crest-derived cells in the gut is always preceded by the appearance of these matrices. On the other hand, substrate or laminine and collagen type IV appears to promote outgrowth of neurites from settled neural-crest-derived cells and their maturation. The distribution of these matrices within the pathway seems consistent with their role in navigating the neural-crest-derived cells toward their final destination. Enteric neurogenesis is dependent on these matrices, and their alteration in early embryonal stage may be a significant factor in the pathogenesis of Hirschsprungs disease.


Journal of Pediatric Surgery | 1992

Therapeutic significance of surgery in advanced neuroblastoma: A report from the study group of Japan

Yoshiaki Tsuchida; Jotaro Yokoyama; Michio Kaneko; Junichi Uchino; Makoto Iwafuchi; Shun-ichi Makino; Shiro Matsuyama; Hideyo Takahashi; Ikuo Okabe; Kohhei Hashizume; Akira Hayashi; Kohnosuke Hakada; Seishichi Yokoyama; Hirokazu Nishihira; Shingi Sasaki; Tadashi Sawada; Noboru Nagahara; Akira Okada

The role of surgery was evaluated in 19 stage III and 102 stage IV neuroblastoma patients, all of whom were treated with intensive induction chemotherapy by the Study Group of Japan between January 1985 and March 1990. For stage III neuroblastoma, surgical intervention at the primary site was performed in 18 of the 19 patients, 9 during and 9 after the first three cycles of A1 regimen, consisting of high-dose cyclophosphamide, vincristine, THP-adriamycin, and cis-platinum. Gross complete resection of primary tumor and regional lymph nodes was feasible in 17 of the 19 patients (89%), and the survival rate for the 17 patients were 79%, 70%, and 70% at 2 years, 3 years, and 4 years, respectively. For stage IV, surgical intervention at the primary site was performed in 92 of the 102 patients (90%): 30 cases during the first 3 cycles of A1 chemotherapy and 62 cases after that, with gross complete resection accomplished in 81 of the 102 patients (79%). The 81 patients with gross complete resection achieved had a better prognosis than those 11 patients with partial resection (P less than .05). Overall survival rate was 62% at 2 years for 27 patients who underwent complete resection after 3 cycles of A1 when resolution of all metastases was obtained, whereas the survival was 52% at 2 years for 31 patients who similarly underwent complete resection but when evidence of persistent metastases was present. Patients in whom the ipsilateral kidney was preserved at surgery had an outcome superior to that of those with associated nephrectomy (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)


Journal of Parenteral and Enteral Nutrition | 1993

Complication of Parenteral Nutrition Composed of Essential Amino Acids and Histidine in Adults With Renal Failure

Hisao Nakasaki; Tokitaka Katayama; Seishichi Yokoyama; Tomoo Tajima; Toshio Mitomi; Michio Tsuda; Takao Suga; Koichi Fuj

This is a case report on six patients with hyperammonemia that developed while they were receiving total parenteral nutrition (TPN) as a component of renal failure therapy. Clinically, the hyperammonemia presented as mental status changes in all six cases. Four of the six patients with renal failure initially received 400 mL Amiyu in 1400 mL 17% glucose (total = 1800 mL TPN-A) administered over each 24-hour period. Two patients had been placed on 400 mL complete amino acid in 1400 mL 17% glucose (total = 1800 mL TPN-C over each 24-hour period) prior to therapy with TPN-A. Approximately 3 weeks after initiation of TPN therapy with TPN-A, episodes of mental status changes of increasing duration and paroxysms were documented in five of the six patients. In one of the patients receiving TPN-C prior to TPN-A therapy, toxicity was clinically evident only 4 days after initiation of TPN-A. Serum ammonia levels were obtained and found to be elevated in the acute (ie, presenting) stage in all patients. With the discontinuance of TPN-A, ammonia levels normalized uniformly. Mental status also improved in all cases except for the patient with rapid clinical presentation who died 2 weeks after first evidence of clinical toxicity. In cases 1, 2, and 6, serum amino acid analysis in the acute phase showed reduced levels of ornithine and citrulline, the substrate and product, respectively, of condensation with carbamyl phosphate at its entry into the urea cycle. Moreover, levels of arginine, precursor to ornithine, were found to be elevated.(ABSTRACT TRUNCATED AT 250 WORDS)


Pediatrics | 1999

Neuroblastoma of the Urinary Bladder, Preclinically Detected by Mass Screening

Seishichi Yokoyama; Hitoshi Hirakawa; Shigeru Ueno; Hiromasa Yabe; Nobuyoshi Hiraoka

Background. Since the introduction of mass screening of infants for neuroblastoma, the incidence of neuroblastoma has increased in Japan. The reason for this increased incidence is the possible inclusion of many neuroblastomas that would have regressed spontaneously and would never have been detected clinically. An extremely rare tumor at the dome of the urinary bladder in a 7-month-old infant was detected by the mass screening. Methods. A case of neuroblastoma of the urinary bladder is reported with a review of the literature. The data in the Japan Childrens Cancer Registry are also reviewed to analyze the incidence and the site of origin of neuroblastoma for evaluation of mass screening. Results. A 7-month-old female infant was referred because of a positive urine vanillylmanderic acid screening test. Ultrasonography showed a solid mass attached to the urinary bladder. At laparotomy a 35 × 30 × 25-mm egg-shaped tumor was found at the dome of the bladder, and a partial cystectomy was performed. During the operation no changes in blood pressure occurred when the tumor was manipulated. Histologic diagnosis was rosette-fibrillary neuroblastoma originating in the bladder wall, with a favorable Shimada histopathologic classification. N-myc was not amplified, which predicted a favorable prognosis, and no postoperative chemotherapy was given. The patient was free of symptoms and tumor after a follow-up period of 16 months. Literature review revealed that this was the second case of neuroblastoma of the urinary bladder ever reported in the world, although several cases of pheochromocytoma originating in the bladder wall had been reported. Both neuroblastoma and pheochromocytoma derive from the neural crest. The sympathogonia from the neural crest, a common stem cell, differentiates into a ganglion cell or into a secretory cell known as a chromaffin cell, able to manufacture catecholamines. The first case in the world that was reported as neuroblastoma of the urinary bladder was in a 4-month-old infant who was noted to have a 4-cm lower abdominal mass on routine physical examination. A ganglioneuroblastoma of the dome of the bladder was excised and the patient was doing well. On reviewing the Japan Childrens Cancer Registry, the incidence of neuroblastomas in infants has increased as well as the number of stage 1, 2, and 4s (stage 4 special) neuroblastomas since the introduction of mass screening. However, there has been no significant change in the number of stage 3 or 4 diseases diagnosed in older children. According to the Japan Childrens Cancer Registry, pelvic origin neuroblastoma, which has been noted to have spontaneous regression, was more frequent in the primary tumors detected by mass screening when compared with those presenting clinically. During preparation of this manuscript another case of bladder dome neuroblastoma was detected by urinary vanillylmanderic acid screening of 6-month-old infants for neuroblastoma in Japan. Conclusion. These extremely rare cases of neuroblastoma of the urinary bladder involved children younger than 1 year of age and were incidentally detected by routine physical examination or mass screening. This raises the question of whether these tumors might have regressed spontaneously had they gone undetected and untreated.


Journal of Pediatric Surgery | 1973

High-calorie parenteral alimentation: Serum lactic and pyruvic acid levels in immature dogs during infusion with concentrated glucose solutions

Kenro Nakajima; Yoshinori Hirai; Seishichi Yokoyama; Malcolm L. Williamson; Daniel M. Hays

Abstract Solutions of glucose of varying concentrations (10%–25%) were administered through central venous catheters to immature dogs in volumes greater than those employed in clinical total parenteral infusion therapy. Blood lactate and pyruvate levels were not raised during the course of the infusion, irrespective of the glucose concentration employed. Acidosis was not produced by these infusions. Glucose concentrations of approximately 20% were utilized most effectively, as demonstrated by total glucose retention. Clinical lactic acidemia is probably not adversely affected by continued infusion of high concentrations of glucose.


The Tokai journal of experimental and clinical medicine | 2002

Tracheal Agenesis : A Case Report

Hitoshi Hirakawa; Shigeru Ueno; Seishichi Yokoyama; Jinichi Soeda; Tomoo Tajima; Toshio Mitomi; Hiroyasu Makuuchi


Pediatrics | 2002

Use of Real-Time Magnetic Resonance Guidance to Assist Bone Biopsy in Pediatric Malignancy

Shigeru Ueno; Seishichi Yokoyama; Hitoshi Hirakawa; Hiromasa Yabe; Yutaka Suzuki; Hideki Atsumi; Mitsunori Matsumae


The Tokai journal of experimental and clinical medicine | 1993

Use of Cultured human epidermal allografts for the treatment of extensive partial thickness scald burn in children

Jinichi Soeda; Sadaki Inokuchi; Shigeru Ueno; Seishichi Yokoyama; Masako Kidokoro; Yoshihiko Nakamura; Shun-ichi Katoh; Yuhwsuke Sawada; Mitsuhiro Osada; Toshio Mitomi


The Tokai journal of experimental and clinical medicine | 1997

Alterations in Glutathione Peroxidase Activity following Reperfusion Injury to Rat Liver

Tokitaka Katayama; Seishichi Yokoyama; Toshio Mitomi; Keiichi Watanabe


Pediatrics | 1997

Twenty-four-hour profile of growth hormone in cyclic nocturnal total parenteral nutrition.

Seishichi Yokoyama; Hitoshi Hirakawa; Jinichi Soeda; Shigeru Ueno; Toshio Mitomi

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