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Dive into the research topics where Masahiko Urao is active.

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Featured researches published by Masahiko Urao.


Journal of Pediatric Surgery | 1997

A comparison of the efficacy of pyloromyotomy and pyloroplasty in patients with gastroesophageal reflux and delayed gastric emptying

Hiroomi Okuyama; Masahiko Urao; Gregory A Starr; Robert A. Drongowski; Arnold G. Coran; Ronald B. Hirschl

PURPOSE Delayed gastric emptying (DGE) in children with gastroesophageal reflux (GER) is often treated with a gastric emptying procedure. Although pyloroplasty is the most common gastric emptying procedure performed, pyloromyotomy is easier to perform and is associated with less morbidity. The aim of this study was to compare the efficacy of pyloromyotomy and pyloroplasty in children with DGE and GER undergoing a fundoplication. MATERIALS AND METHODS We reviewed the charts of 54 patients with DGE who underwent pyloromyotomy (n = 29), or pyloroplasty (n = 25) along with a fundoplication. A technetium 99-labeled sulfur colloid liquid-phase gastric emptying study (GES) was performed in the pre- and early postoperative period (within 6 months after operation). Normal stomach emptying was defined as greater than 40% at 1 hour. Comparisons were made with regard to postoperative complication rate, incidence of redo fundoplication, length of postoperative hospital stay, and pre- and postoperative GES. RESULTS The pyloroplasty and pyloromyotomy group were comparable in terms of age, sex, operative indications, and neurological status. There was no significant difference in the GES between the two groups preoperatively. There was a trend toward a decreased incidence of early postoperative complications including gas bloat, wound infection, pneumonia, dysphagia, bowel obstruction and dumping syndrome in the pyloromyotomy (8, 28%) when compared with the pyloroplasty group (12, 48%, P = .10). The mean postoperative hospital stay was 10.6 +/- 1.4 days for the pyloroplasty group and 7.6 +/- 1.0 days for the pyloromyotomy group (P + .08). The incidence of a redo fundoplication was 8% in the pyloroplasty and 7% in the pyloromyotomy group. Postoperative gastric emptying increased significantly in both groups (pyloroplasty group, from 18.1 +/- 3.1 to 49.5 +/- 7.9%, P = .0005; pyloromyotomy group, from 19.3 +/- 2.1 to 41.2 +/- 3.7%, P = .0001). There was no significant difference in the postoperative GES between the two groups (P = .289). CONCLUSION Both pyloroplasty and pyloromyotomy performed in conjunction with a fundoplication resulted in a significant increase in early postoperative gastric emptying. There was no advantage of pyloroplasty over pyloromyotomy during this follow-up period. These data suggest that pyloromyotomy is an effective gastric emptying procedure in children with GER and DGE.


Journal of Pediatric Surgery | 1999

Does probiotics administration decrease serum endotoxin levels in infants

Masahiko Urao; Takao Fujimoto; Geoffrey J. Lane; Gen-ichiro Seo; Miyano Takeshi

PURPOSE The aim of this study was to examine whether administration of probiotics to infants can change the ratio of intestinal flora and thereby decrease serum endotoxin produced by potentially pathogenic microorganisms. METHODS Nine infants including five with of biliary atresia, two with omphalocele, one each with Hirschsprungs disease and imperforate anus were studied. All patients were stable, and no antibiotics were given during this study. A probiotic mixture consisting of Streptococcus faecalis, Clostridium butyricum and Bacillus mesentericus was administered orally to each infant at 2 g/day for 2 weeks. Fecal aerobic and anaerobic bacterial cultures, serum endotoxin level, and other biochemical parameters were examined. RESULTS In fecal cultures, anaerobic bacteria including Bifidobacterium increased significantly whereas Escherichia coli, Streptococcus, and Klebsiella tended to decrease. The ratio of anaerobic to aerobic bacteria increased five times as a result of administration of probiotics, and serum endotoxin levels decreased. CONCLUSIONS Probiotics affect intestinal bacterial flora by increasing anaerobic bacteria and decreasing the population of potentially pathogenic microorganisms. A decrease in luminal endotoxin may result in less endotoxin translocation or bacterial translocation.


Journal of Pediatric Surgery | 1998

The effect of epidermal growth factor on bacterial translocation in newborn rabbits

Hiroomi Okuyama; Masahiko Urao; David Seungjae Lee; Robert A. Drongowski; Arnold G. Coran

PURPOSE Epidermal growth factor (EGF), which is present in breast milk, has both trophic and maturational effects on intestinal mucosa. The aim of this study is to determine the effect of EGF on spontaneous intestinal bacterial translocation (BT) in formula-fed newborn rabbits, who have a high incidence of BT compared with breast-fed newborn rabbits. METHODS Sixty-one rabbit pups were divided into three groups: EGF(-), n=24, EGF(+), n=22, and breast-fed animals, n=15. Both the EGF(-) and EGF(+) groups were gavage fed a standard artificial formula three times daily. EGF was administered subcutaneously three times daily (1.5 microg/g body weight per day) in the EGF(+) group. The breast-fed group was fed by their mothers ad libitum. At 7 days of age, all rabbits were killed, and the mesenteric lymph nodes (MLN), liver, and spleen were cultured qualitatively for bacterial growth, while the cecum and ileum were quantitatively cultured. To determine the effect of EGF on mucus-producing cells, goblet cell numbers in the small intestine were quantified histologically. RESULTS There was no BT to MLN, spleen, or liver in the breast-fed group. The incidence of BT to MLN and spleen was significantly lower in the EGF(+) compared with EGF(-) group; (EGF[+]: MLN, 45%; spleen, 32%; Liver, 27%; EGF[-]: MLN, 79%; Spleen 67%; Liver 29%; in EGF[+] MLN and Spleen P<.05 vEGF[-]). There was no significant difference in cecal and ileal bacterial colonization between the EGF(+) and EGF(-) groups. The number of goblet cells in the small intestine was significantly lower in the EGF(-) group compared with the EGF(+) group as follows: EGF(+), 14+/-3; EGF(-), 9+/-3; breast-fed, 11+/-5 goblet cells per 100 epithelial cell nuclei; P=.013. CONCLUSIONS (1) EGF caused a significant decrease in spontaneous bacterial translocation in formula-fed newborn rabbits and was associated with an increase in the goblet cell number of the small intestine. (2) These changes occurred in spite of the fact that no changes in small bowel bacterial colonization were observed. (3) These results suggest, but do not prove, that EGF may provide protection for neonates from gut origin infection by improving the mucosal barrier function through increased goblet cell production, thus decreasing the incidence of spontaneous bacterial translocation in the newborn.


Journal of Pediatric Surgery | 1996

The association of gut-associated lymphoid tissue and bacterial translocation in the newborn rabbit.

Masahiko Urao; Daniel H. Teitelbaum; Robert A. Drongowski; Arnold G. Coran

The authors have previously demonstrated spontaneous bacterial translocation (BT) in newborn rabbits and its resolution with aging. It is hypothesized that this spontaneous BT was associated with an immature gut-associated lymphoid tissue (GALT). The aim of the present study was to characterize the cellular populations of the GALT in rabbits at various ages and to correlate this with the frequency of BT. Small bowel (SB) sections and mesenteric lymph nodes (MLN) were harvested and cultured (aerobically) from New Zealand White rabbits at 0, 6, 14, 28, and more than 90 days of age for determination of bacterial colonization (BC) and BT. Portions of ileum (n = 6 for each age) were simultaneously harvested for immunoperoxidase staining. Total T cells (CDS+), expressed as the number of positive cells/1000 nuclei and activated T cells (CD25+), expressed as the number of positive cells/1000 nuclei and as the ratio of CD25+/CD5+ cells, were analyzed for each tissue. Positive cells were counted in 30 villi by light microscopy. The incidence of BT rose as BC increased in the small bowel and peaked at 6 days of age; BT then decreased with age. CD5+ cells in the small bowel villi at 0 days of age were few (2.5 positive cells/1000 nuclei) and the number significantly increased with age (6 days, 6.5; 14 days, 19.0; 28 days, 31.6; adult, 136.6 positive cells/1,000 nuclei). The distribution of T cells started in the crypts, and with advancing age, cells were found all the way to the top of the villi. The number of CD25+ cells in the villi increased with age. The CD25+/CD5+ ratio in the small bowel villi peaked at 6 days of age. These results demonstrate an inverse relationship between the number of CD5+ cells in the intestinal villi and the incidence of bacterial translocation. The elevation of activated T cells (CD25+) at 6 days of age may be the result of an immunologic activation during the time of peak bacterial translocation. These data suggest that maturity of the GALT leads to a loss of spontaneous bacterial translocation in the newborn period. Modalities that supplement the GALT may help reduce bacterial translocation.


Journal of Pediatric Surgery | 1996

Lingual thyroglossal duct cyst: A unique surgical approach

Masahiko Urao; Daniel H. Teitelbaum; Takeshi Miyano

Thyroglossal duct cyst (TGDC) is one of the more common causes of a pediatric neck mass. Lingual TGDC, which is located at the base of the tongue, is an unusual variant. Because of the oral pharyngeal location, lingual TGDC may cause dysphagia and respiratory distress. Previous investigators have advocated the use of a formal Sistrunk procedure for lingual TGDC. Herein the authors describe three children with a lingual TGDC in whom marsupialization of the cyst was performed, without excision. The follow-up period ranges from 2 to 5 years, and there has been no recurrence. Because of the low morbidity and high success rate associated with this approach, the authors recommend it for the treatment of lingual TGDC.


Journal of Pediatric Surgery | 1995

Determinant of bacterial translocation in the newborn: small bowel versus large bowel colonization.

Masahiko Urao; Jason Moy; Joan M. Van Camp; Robert A. Drongowski; Maher Altabba; Arnold G. Coran

This study investigated the relationship between bacterial translocation (BT) and small and large bowel bacterial colonization in the neonatal rabbit. The authors have previously shown that spontaneous BT occurs in rabbits during the first week of life, but is less frequent before the third day of life. The authors have also shown that bacterial colonization of the small bowel, is delayed until 3 to 5 days of age, and is preceded by colonization of the large bowel. Therefore, the authors hypothesizes that BT is dependent on small bowel, not large bowel, colonization. New Zealand White rabbit pups (n = 255) were divided into four groups, formula-fed (FF), formula-fed plus antibiotic (FFAB), breast-fed (BF) and unfed controls (UC). Animals from each group were killed on day 1 to 4 of life. Small bowel (SB) and large bowel (LB) specimens, mesenteric lymph nodes (MLN), spleen (SPL), and liver (LIV) were obtained from each rabbit, incubated for 24 hours in thioglycolate broth, and plated on both MacConkey and Colistin Naladixic Acid media in an aerobic environment. After 24 hours, growth on either plate was recorded. Bacterial colonization was significantly greater in FF versus UC, BF, and FFAB rabbit groups. In addition, large bowel colonization was significantly increased compared with small bowel colonization in all feeding groups (P < .05). Bacterial translocation to MLN, SPL, and LIV ranged from 10% to 27% in all groups. Gram-negative bacteria predominated over gram-positive bacteria in translocation to the various tissues sampled.(ABSTRACT TRUNCATED AT 250 WORDS)


Journal of Pediatric Surgery | 1997

Intestinal Permeability to Small- and Large-Molecular-Weight Substances in the Newborn Rabbit

Masahiko Urao; Hiroomi Okuyama; Robert A. Drongowski; Daniel H. Teitelbaum; Arnold G. Coran

BACKGROUND/PURPOSE The authors have previously reported the occurrence of spontaneous bacterial translocation (BT) and its resolution with age in the newborn rabbit. They have also reported a close correlation between small bowel bacterial colonization (BC-SB) and BT at 1 week of age, suggesting that the presence of luminal bacteria and their production of endotoxins may increase the intestinal permeability. The aim of this study was to evaluate intestinal permeability to small and large molecules in the newborn rabbit and to correlate it with BT. MATERIALS AND METHODS New Zealand White rabbits (n = 96) 1, 7, 14, 21, and over 120 days (adult) of age were given either C14-labeled ethylene diamine tetraacetic acid (EDTA) (MW 290) or C14-Dextran (MW 70,000) via an orogastric tube at 1 mCi per 100 g of body weight. Five hours later, blood, urine, liver, and intestine were collected, and scintillation counting was performed after solubilization. In a separate series of rabbits (n = 136), the incidence of BT, BC-SB, and small intestinal surface area (SA) were measured. RESULTS Total permeability to Dextran decreased with age and was significantly reduced at 14 days of age. In contrast, total permeability to EDTA increased and was maximal in 7- to 14-day-old rabbits and began to decrease at 21 days of age. The incidence of BC-SB rapidly increased at 7 days of age and reached 100% at 14 days of age. The incidence of BT peaked at 7 days of life (30%) and then decreased with age. SA increased rapidly in the first 3 weeks and SA growth rate of 21-day-old rabbits was almost 1,400% compared with 1-day-old rabbits. CONCLUSIONS This study has shown an age-related reduction of intestinal permeability to large (Dextran) and small (EDTA) molecular weight particles. However, intestinal permeability to EDTA had a different pattern than Dextran, suggesting that there may be different mechanisms of intestinal permeability to different size molecules. Intestinal permeability to EDTA closely correlated with bacterial colonization and bacterial translocation, suggesting that changes in the intestinal bacterial environment may affect the intestinal permeability, possibly by activating the immune system secondary to increases in endotoxins and bacteria.


Journal of Pediatric Surgery | 1994

Effects of ursodeoxycholic acid treatment on essential fatty acid deficiency in patients with biliary atresia

Yuichiro Yamashiro; Yoshikazu Ohtsuka; Toshiaki Shimizu; Hiroshi Nittono; Masahiko Urao; Takeshi Miyano; Satomi Kawakami; Hirotoshi Hayasawa

To assess whether ursodeoxycholic acid (UDCA) treatment has any beneficial effect on essential fatty acid (EFA) deficiency in patients who have had a Kasai operation for extrahepatic atresia (EBA), responses of serum fatty acids to UDCA administration (15 mg/kg/d) were investigated in eight jaundice-free patients and in eight patients with jaundice (serum total bilirubin > or = 1.0 mg/dL). All patients were also given taurine supplementation (100 mg/kg/d). Serum fatty acid composition was determined before and 6 months after UDCA treatment. Serum total bile acid concentration and serum total bilirubin value, as a part of conventional liver function tests, were measured before and during UDCA therapy. Before UDCA treatment, the concentrations of linoleic acid and arachidonic acid were significantly lower (P > .05 for the former; P > .01 for the latter) in both the jaundice and jaundice-free groups than in the controls. After 6 months of treatment, the linoleic acid concentration significantly increased (P > .05), to the normal range, in the jaundice-free group, but not in the jaundice group. The arachidonic acid concentration did not increase significantly in either group. The serum total bile acid concentration was lower in six of the eight jaundice-free patients and in four of the eight jaundice patients. The serum total bilirubin value decreased in six of the eight jaundice-free patients and in four of the eight jaundice patients; however, the degree of improvement was not statistically significant in either group. No side effects developed, and there were no changes in blood chemistry values unrelated to liver disease.(ABSTRACT TRUNCATED AT 250 WORDS)


Journal of Pediatric Surgery | 1992

Hirschsprung's disease : diagnosis using monoclonal antibody 171B5

Atsuyuki Yamataka; Takeshi Miyano; Masahiko Urao; Hiroshi Nishiye

A new reliable immunohistochemical method for diagnosing Hirschsprungs disease (HD) using our unique monoclonal antibody (MAb) 171B5 against synaptic vesicles is described. Fresh frozen sections of rectal tissues were used from 13 patients with HD aged 2 weeks to 13 months; 9 had rectosigmoid HD and 4 had total colonic aganglionosis (TCA). Comparable normal colonic and rectal specimens were also obtained from 13 age-matched controls. All specimens were labeled with MAb 171B5, to demonstrate neuronal innervation patterns of both mucosa and submucosa. In all control specimens, many synapses arranged in variciform plexuses were seen in the lamina propria, a moderate number in the muscularis mucosae, and dense clusters in the submucosal plexus. In all aganglionic specimens, only scanty numbers of synapses which were not organized in variciform plexuses were seen in the lamina propria, none in the muscularis mucosae, and a few in the submucosa. These findings suggest that MAb 171B5 immunohistochemistry on the lamina propria alone can differentiate between normal and aganglionic bowel and appears to be a reliable and useful method for detecting HD on suction rectal biopsy.


Journal of Laparoendoscopic & Advanced Surgical Techniques | 2011

A Prospective Analysis of Endoloops and Endostaples for Closing the Stump of the Appendix in Children

Go Miyano; Masahiko Urao; Geoffrey J. Lane; Yoshifumi Kato; Tadaharu Okazaki; Atsuyuki Yamataka

AIM The aim of this study was to compare endoloops and endostaples for closing the stump of the appendix during laparoscopic appendectomy (LA) for uncomplicated appendicitis in children. METHODS All LA performed for appendicitis from 2005 to 2009 were analyzed prospectively. Cases of complicated appendicitis such as perforated appendicitis or intra-abdominal abscess were excluded, leaving 75 cases closed with loops and 81 cases closed with staples. Choice of technique was determined by the attending surgeons preference. All patients were managed according to the same pre-, intra-, and postoperative protocols. RESULTS There were no significant differences between mean age at surgery, gender ratio, preoperative mean white blood cell count and mean C-reactive protein, histopathologic findings, mean duration of surgery, and mean hospitalization. There were no intra-operative complications in either group, but one loop case required conversion to open surgery (P = NS). There were no significant differences in the incidences of intra-abdominal abscess, transient ileus, small bowel obstruction, and wound infection. The postoperative readmission rate for management of complications was 4.0% for loop cases and 2.5% for staple cases (P = NS). Overall, using staples for a standard LA (anesthesia and stump closure) was U.S.

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Toshihiro Yanai

Boston Children's Hospital

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