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Featured researches published by Masao Endo.


Transplantation | 1997

Interleukin-1 receptor blockade reduces tumor necrosis factor production, tissue injury, and mortality after hepatic ischemia-reperfusion in the rat

Masaya Shito; Go Wakabayashi; Masakazu Ueda; Motohide Shimazu; Nozomu Shirasugi; Masao Endo; Makio Mukai; Masaki Kitajima

The inflammatory cytokines interleukin (IL) 1 and tumor necrosis factor (TNF) may play an important role in hepatic ischemia-reperfusion (I/R) injury. To study the role of IL-1 in hepatic I-R injury, we investigated the effect of pretreatment with IL-1 receptor antagonist (IL-1ra) on the production of IL-1, TNF, histological findings in the liver, and the survival rate for 7 days. Rats were subjected to 90 min of partial liver warm ischemia by clamping the vessels of the left and middle lobes. In the IL-1ra-treated group, IL-1ra was given 5 min before liver ischemia was induced. IL-1alpha and TNF levels were determined in blood and liver at 0, 30, 90, and 180 min after reperfusion. In a second experiment to determine the effect of IL-1ra pretreatment on survival rate, after 90 min of partial liver ischemia, the right lateral and caudate lobes were excised, leaving only the ischemic lobes. In both groups, IL-1alpha was undetectable in blood, but increased in liver tissue. TNF increased in both blood and liver tissue as reperfusion time increased. Histological evidence of tissue injury was minimal in the IL-1ra-treated group. Furthermore, in the IL-1ra-treated group, the production of TNF decreased in both blood and liver tissue compared with the nontreated group. Survival rates in the IL-1ra-treated and nontreated group were 80% and 30%, respectively. The data demonstrated that the production of IL-1 and TNF increases in hepatic I-R injury and that pretreatment with IL-1ra protects the liver from ischemic insult, indicating an important role for IL-1 in I-R injury.


Journal of Pediatric Surgery | 1999

Analysis of 1,992 patients with anorectal malformations over the past two decades in Japan

Masao Endo; Akira Hayashi; Michiomi Ishihara; Masahiko Maie; Akira Nagasaki; Toshiji Nishi; Morihiro Saeki

BACKGROUND/PURPOSE This report describes the results of a group study of the Japanese Study Group of Anorectal Anomolies (JSGA) to determine the relative incidence of specific types of anorectal anomaly in Japan, and includes discussion of rectourethral fistula regarding the relationship between the levels of the fistula and blind end of the rectum, low type deformity, rare types, and associated anomalies. METHODS A total of 1,992 patients (1,183 boys and 809 girls) registered from 1976 to 1995 were analyzed. RESULTS High-type deformities accounted for 26.0% of cases, intermediate 10.7%, low 57.2%, miscellaneous 4.5% and unclassified 1.8%. The most frequent deformity was male anocutaneous fistula (n = 364), followed by male rectourethral fistula (n = 333), and female anovestibular fistula (n = 241). There were 42 rectovesical fistulas in boys and 93 rectocloacal fistulas in girls. Covered anus complete occurred at the same frequency (10.1% of low deformities) as covered anal stenosis. In rectourethral fistula, the blind end of the rectum lay at or above the level of the P-C line in 40.3% of cases, at or above the M line in 39.6% and at the vicinity of the I line in 20.2%, respectively. There was no parallel relationship between the site of the fistula opening and the level of the rectal pouch. The overall incidence of patients having one or more associated anomalies was 45.2%: 70.6% in high deformity, 60.7% in intermediate, and 31.3% in low. The rate of association of Downs syndrome with deformities without fistula (40.3%) was significantly higher than with deformities with fistula (0.3%). CONCLUSIONS Rectovesical fistula and covered anus complete were not infrequent deformities in this series. We consider that at least 20% of rectourethral fistula should be categorized as intermediate or low deformity from the viewpoint of the position of the rectal pouch. A significant preponderance of Downs syndrome in the deformities without fistula suggests that further investigation of associated anomalies in comparision with other congenital diseases may provide insights into the pathogenesis of anorectal malformation in the field of molecular genetics.


Journal of Pediatric Surgery | 1983

Extended dissection of the portahepatis and creation of an intussuscepted ileocolic conduit for biliary atresia.

Masao Endo; Keizo Katsumata; Jotaro Yokoyama; Yasuhide Morikawa; Hiromichi Ikawa; Shoichiro Kamagata; Miwako Nakano; Yuji Nirasawa; Shigeru Ueno

This paper introduces a new operation for biliary atresia that establishes successful biliary drainage by extending the portahepatic dissection, and decreases ascending cholangitis by incorporating a nonrefluxing intussuscepted draining conduit. An analysis of the postoperative results is presented. The usual dissection of the portahepatis is extended to include the area between and beneath the branches of the right portal vein to incorporate all potentially usable remnants of the intrahepatic ducts. Ascending cholangitis is decreased by interposing an intussuscepted ileocolic segment between the portahepatis and the abdominal wall. This extended dissection of the portahepatis was performed since 1978 in 15 infants with noncorrectable biliary atresia, and bile drainage was achieved in all. In ten infants an intussuscepted ileocolic conduit was constructed. Ascending cholangitis in these ten infants has been either completely absent or easily controlled by antibiotics. The draining bile was highly concentrated due to the water-absorbing capacity of the interposed colonic segment; therefore, fluid and electrolyte disturbances, which develop frequently in patients having jejunal conduits, have never been encountered.


Journal of Pediatric Surgery | 1985

The use of computerized tomography to evaluate anorectal anomalies

Hiromichi Ikawa; Jotaro Yokoyama; Toru Sanbonmatsu; Kazuhiko Hagane; Masao Endo; Keizo Katsumata; Eiichi Kohda

Computerized tomography (CT) was applied to various types of anorectal anomalies to directly image the anal sphincters. In normal cases and low type anomalies, CT demonstrated clear images of the puborectal muscle and external sphincters. Among high type anomalies, the distribution of sphincter muscle in patients with rectovesical fistula is totally different from that seen in patients with rectourethral fistula. In the latter, the puborectal muscle is attached not only around urethra, but also around the distal part of the blind rectum; external sphincters are present as a mass beneath the perineum. In the rectovesical fistula, however, the puborectal muscle cannot be identified and the external sphincters exist only as a string-like structure. CT done postoperatively identified two different causes for incontinence. In one type, the pull-through colon missed the sphincteric musculature, and in the other, sphincters were markedly hypoplastic. CT, therefore, provides adequate imaging to determine the type of operation needed to correct the abnormality.


Pediatric Endosurgery and Innovative Techniques | 2001

Laparoscopic Closure of Patent Processus Vaginalis in Girls with Inguinal Hernia Using a Specially Devised Suture Needle

Masao Endo; Etsuji Ukiyama

Purpose: To introduce a suture needle (Endoneedle) designed for laparoscopic extraperitoneal closure of patent processus vaginalis (PPV). Methods: The Endoneedle consists of 19-gauge hollow needle with a notch near the tip and 2-0 nonabsorbable suture and a plastic sheath. The procedures are performed with the help of a 5-mm telescope inserted through the umbilicus, and a 2-mm Endograsp placed below the umbilicus. Results: Since July 1998, this procedure has been carried out in 61 girls aged 3 months to 14 years. There have been no postoperative complications, and no recurrent hernia. The surgical wounds completely disappeared. In the most recent 10 cases, the mean operative time was 21 minutes for unilateral and 28 minutes for bilateral closure. Conclusion: This procedure is easy and safe, and it has excellent cosmetic results.


Annals of Surgery | 1996

Rapid diagnosis of methicillin-resistant Staphylococcus aureus bacteremia by nested polymerase chain reaction

Yuko Kitagawa; Masakazu Ueda; Nobutoshi Ando; Masao Endo; Kyuya Ishibiki; Yoshio Kobayashi; Toshihiko Arai; Masaki Kitajima

OBJECTIVE The purpose of this study was to establish a rapid and sensitive diagnostic method for methicillin-resistant Staphylococcus aureus (MRSA) bacteremia in postoperative patients. SUMMARY BACKGROUND DATA As a result of diffusion and abuse of third-generation cephalosporin antibiotics in the 1980s in Japan, an outbreak of MRSA infection has been posed. In the field of surgery, severe postoperative infections with MRSA such as MRSA bacteremia, which may lead to multiple organ failure, have emerged with a high mortality. METHODS Thirty-five patients with high fever (above 38.5 C) or watery diarrhea or both within 2 weeks after gastrointestinal major surgery and 6 healthy volunteers were examined. Nested polymerase chain reaction was used to detect mecA and toxic shock syndrome toxin-1 (TSST-1) genes in blood specimens. RESULTS The mecA and TSST-1 genes were not detected in the blood samples of any of the six healthy volunteers. In all 12 samples from which MRSA colonies were isolated by blood culture, mecA and TSST-1 genes were detected. Although it took at least 48 hours to identify MRSA by the blood culture method, the presence of mecA and TSST-1 genes was determined by nested polymerase chain reaction method within only 3 to 4 hours after blood sampling. CONCLUSIONS This method, as a sensitive and rapid monitoring system for MRS bacteremia, would be clinically beneficial for prevention of cross infection and for early determination of appropriate treatment for infected patients.


Critical Care Medicine | 1994

Effect of acute lung injury and coexisting disorders on plasma concentrations of atrial natriuretic peptide

Minoru Tanabe; Masakazu Ueda; Masao Endo; Masaki Kitajima

Objective: To clarify how plasma atrial natriuretic peptide concentrations vary with the severity of acute lung injury. The influence of coexisting diseases which trigger acute lung injury was also examined. Design: Prospective study. Setting: Intensive care unit of a university hospital. Patients: Fifty patients who had standard risk factors for acute lung injury including sepsis syndrome, major surgery, prolonged hypotension, aspiration of gastric contents, and burns. Twenty‐five of these patients had acute lung injury (group 3) caused by these disorders; the remaining 25 patients had risk factors only (group 2). Ten age‐matched normal volunteers were selected as controls (group 1). Intervention: None. Measurements and Main Results: Plasma atrial natriuretic peptide concentration was measured in these patients and compared with the severity of acute lung injury. In group 3, a significant increase in the mean plasma atrial natriuretic peptide concentration was observed (188 ± 78 pg/mL, p < .01) compared with group 2 (54 ± 28 pg/mL) and the age‐matched control group (30 ± 8 pg/mL). This increase was related to the onset of acute lung injury and returned to control concentrations after recovery. Plasma atrial natriuretic peptide concentrations in group 3 correlated highly with a lung injury score representing the severity of acute lung injury (r2 = .45, p < .01), but did not correlate with other cardiopulmonary variables. Conclusion: The results suggest that severity of lung injury, but not other predisposing disorders, may be the key factor leading to the increase in plasma atrial natriuretic peptide concentrations observed in these patients. (Crit Care Med 1994; 22:1762–1768)


Journal of Pediatric Surgery | 2008

An investigation on the mechanism of contralateral manifestations after unilateral herniorrhaphy in children based on laparoscopic evaluation.

Toshihiko Watanabe; Miwako Nakano; Masao Endo

BACKGROUND/PURPOSE No straightforward theoretical descriptions explaining the discrepant incidences of metachronous contralateral hernia and positive contralateral patent processus vaginalis (cPPV) exist. The indications for contralateral groin repair are still not clearly defined. METHODS During laparoscopic herniorrhaphy, the intraoperative appearances of the internal inguinal rings (IIRs) were characterized and classified in 211 children with symptomatic unilateral inguinal hernias. A total of 125 boys and 86 girls with 130 right-sided and 81 left-sided indirect inguinal hernias were examined. The morphological appearances of the IIRs in patients with cPPV were compared before and after the ligation of the symptomatic IIRs. RESULTS Of 211 children, 108 (51%) had positive cPPV findings. The cPPVs had significantly smaller orifices and shorter lengths than those on the side of the symptomatic hernia. Among these children, 24 (22%) patients exhibited morphological changes in their cPPVs, characterized by an upward movement of the overlying peritoneal veil after the closure of the symptomatic hernia. CONCLUSION Metachronous contralateral hernia might occur because of morphological changes to the cPPV resulting from closure of the symptomatic IIRs. The predicted incidence of contralateral hernia in this series was 11.2%.


Journal of Pediatric Surgery | 1997

Impaired expression of neural cell adhesion molecule L1 in the extrinsic nerve fibers in Hirschsprung's disease

Hiromichi Ikawa; Hitoshi Kawano; Yasuo Takeda; Hiroaki Masuyama; Koji Watanabe; Masao Endo; Jotaro Yokoyama; Masaki Kitajima; Keiichi Uyemura; Koki Kawamura

Immunohistochemical studies on the ganglionic and aganglionic segment in Hirschsprungs disease (HD) were carried out using antibodies against three neural membrane proteins, Thy-1, integrin alpha5, and L1. Enteric neural elements were immunostained with antibodies against neurofilament, which is the neuronal cytoskeletal protein. In ganglionic segments, neurofilament-immunoreactivity was detected in neuronal cell bodies and fine nerve fibers of the myenteric and submucosal plexuses. All of these neural elements were immunopositive for Thy-1, integrin alpha5, and L1. In aganglionic segments, no intrinsic neurons were detected, and instead, hypertrophied nerve bundles were observed in intermuscular space, in submucosa, and in circular muscle layer by immunochemistry for neurofilament. These hypertrophied nerve bundles were immunopositive with anti-Thy-1 and anti-integrin alpha5 antibodies. However, they were not immunostained with anti-L1 in all five cases. These findings indicate that the expression of L1 molecule, which plays an important role in cell adhesion, neural cell migration, and neurite outgrowth, is impaired in the extrinsic nerve fibers in aganglionic colon. And this may perturb neural crest migration and adequate neurite outgrowth, with resulting aganglionic segment and abnormal nerve bundles of extrinsic fibers in HD.


Journal of Pediatric Surgery | 1994

Long-term results of surgical treatment in infants with total colonic aganglionosis

Masao Endo; Kouji Watanabe; Yasushi Fuchimoto; Hiromichi Ikawa; Jotaro Yokoyama

The authors describe the long-term results of the surgical treatment of total colonic aganglionosis (TCA) in nine boys who have been treated since 1975. The principal operative procedure was endorectal pull-through of the ganglionic ileum, with the aganglionic colon as an onlay patch. The procedure was employed in five infants, using the right or left colon. Ileorectostomy with an onlay patch was used in two patients; ileoanostomy without the patch was used in two. The distal end of the pulled-through ileum was, on average, 39 cm from the ileocecal junction. The average follow-up period was 11.0 years. Diarrhea and distension were temporary after the pull-through, and all patients ultimately tolerated normal feeding. Considering the variation in operative techniques, we were unable to demonstrate any advantage of one procedure over another. Z scores for height and weight at the last follow-up examination correlated with the weight gain before the definitive surgery and inversely correlated with the length of resected distal ileum at the time of operation.

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Miwako Nakano

Boston Children's Hospital

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Masakazu Ueda

Boston Children's Hospital

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Toshihiko Watanabe

Brigham and Women's Hospital

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