Search PubMed⌕ Search

Biomedical subjects

Yoshinori Hamada

Publications and source records attributed to Yoshinori Hamada.

12 recordsLinked to original sources
PubMed2006

Antenatal magnetic resonance imaging is useful in providing predictive values for surgical procedures in abdominal wall defects.

BACKGROUND: Antenatal magnetic resonance imaging (MRI) is useful for the diagnosis of abdominal wall defects. Its predictive value concerning the possibility of primary closure of the abdominal wall, however, has so far not been reported. METHODS: Between August 2001 and November 2004, antenatal MRI was performed on 9 patients with abdominal wall defects in whom surgical repair was performed immediately after birth. Areas of the abdominal cavity and exteriorized viscera were manually traced from both sagittal and axial MR images, and the data were further transmitted to a Workstation for MRI Volumetry (Advantage Windows 4.1, General Electric Medical Systems, Milwaukee, Wis). We examined the exteriorized ratio (ER), which is calculated by dividing the absolute volume of the abdominal cavity by that of the exteriorized viscera, and evaluated the predictive value by a retrospective comparison with surgical procedure. RESULTS: In the primary closure group (n = 5), mean values of ER were 0.33 +/- 0.31 from axial and 0.45 +/- 0.31 from sagittal MR images. In contrast, in the staged closure group (n = 4), mean values of ER were 1.39 +/- 0.40 from axial and 1.34 +/- 0.42 from sagittal MR images. There was a significant difference (P < .05) between the 2 groups for both sets of images. The ER obtained from antenatal MRI correlated well with surgical procedure. CONCLUSIONS: The ER might be useful for antenatal counseling, planning for delivery, and prediction of the most likely surgical procedure.

Abdominal Wall↗
PubMed2005

Structural development of PGP9.5-immunopositive myenteric plexus in embryonic rats.

To investigate relationships between changes in the 3-dimensional structure of the myenteric plexus and the time at which functional movement of intestine begins in mammalian embryos, whole mounts of embryonic rat intestine were examined under confocal laser scanning microscopy on spacer-equipped glass slides after immunostaining with antiprotein gene product 9.5 antibody. At embryonic day 12.5, very few nerve cells were scattered throughout the small intestine, but no immunostained structures were apparent on the anal side of the large intestine. At embryonic day 13.5, immunostained fibers appeared on the oral side of the large intestine. Nerve cells and associated fiber bundles formed neuronal networks with large meshes in both intestines. Marked increases in number of nerve fibers and decreases in mesh size were seen in the small intestine between embryonic days 13.5 and 15.5. Similar changes were found in the large intestine between embryonic days 13.5 and 16.5. After embryonic day 16.5, nerve cells were arranged parallel to circular muscle fibers, and networks formed by cell fibers elongated until the neonatal period in both intestines. Meconium passed through the large intestine from embryonic day 17.5. Thin fiber bundles extended from the ganglion to the inner side of the myenteric layer, parallel (and occasionally extending) to the circular muscle fibers. Formation of nerve fiber networks and arrangement of nerve cells parallel to circular muscle fibers probably relate to movement coordination for inner circular muscle fibers in the intestinal wall, and development of this neural network may be important for acquiring intestinal movements before birth.

Animals↗
PubMed2005

Congenital biliary dilatation in dizygotic twins.

Congenital biliary dilatation (CBD) of different types was recently noted in dizygotic twins. Our cases suggest the possibility of hereditary involvement in CBD. On the other hand, CBD discordance in six sets of monozygotic twins has been reported, which would suggest that the occurrence of CBD is not compatible with single gene control, although environmental factors are plausible. To evaluate the genetic factors that may be implicated in CBD, it would be necessary to accumulate more familial cases and examine further studies on inheritance.

Anastomosis, Surgical↗
PubMed2005

Thoracoscopic diaphragmatic procedures under artificial pneumothorax.

Diaphragmatic plication is technically simple using a conventional operative technique, but it requires a large skin incision and rib injury. We present an alternative technique for thoracoscopic plication of the diaphragm and evaluate the advantages of the procedure. Six patients (five with diaphragmatic eventration and one with diaphragmatic hernia with a sac) ranging in age from 8 to 20 months were treated by this method. Three of the six cases were right-sided, and three were left-sided. The operation was performed under artificial pneumothorax using carbon dioxide gas at 4 mmHg. Three trocars for laparoscopy were inserted at the 4th and 5th intercostal spaces. An adequate operative view was obtained by pressing the diaphragm throughout the operation. The eventrated diaphragm was plicated with several rows of nonabsorbable sutures in the anterolateral-to-posterolateral direction to prevent injury to the main phrenic nerve. A tight diaphragm was confirmed by decompressing the artificial pneumothorax. The technique was successfully performed in all cases, and the patients' postoperative courses were uneventful. During the operation, the hemodynamic effects of carbon dioxide gas at 4 mmHg were minimal. Over a mean follow-up period of 3.1 years (range, 1-6 years), no recurrence of diaphragmatic eventration was seen. Judging from the satisfactory postoperative course, this procedure is suitable for children with all forms of diaphragmatic eventration.

Diaphragmatic Eventration↗
PubMed2005

[Effects and measures of the flat payment system based on the diagnosis procedure combination system in pediatric surgery].

The current status of the flat payment system based on the diagnosis procedure combination (DPC) system was examined in pediatric surgery. Many important diseases especially in neonatal surgery are not listed for the DPC system due to either the small number of cases or variations in hospital stay or cost In our university hospital, however, the DPC system was applied to 286 (90.8%) of 315 admissions. Total scores for the admissions were slightly higher (103.5%) in the DPC system compared with the fee-for-service system. Scores for inguinal hernia by day surgery and one-night stay were also slightly higher (102.2%) in the DPC system. Future measures for the DPC system include the provision that most preoperative evaluations should be performed in outpatient clinics and further elective surgery at a separate admission is recommended for patients with benign disease or in good condition. In cases of surgery for emergencies or malignancies, too many examinations should be avoided. Postoperative treatment using a clinical path without complications should be performed to achieve shortening of hospital stays and reduced cost. Problems in the current DPC system are complicated and inadequate classification, probably due to the unique and cost-unbeneficial nature of pediatric surgery. To establish a better medical fee system, further efforts to improve the DPC system should be continued.

Child↗
PubMed2004

Further evidence that epidermal growth factor enhances the intestinal adaptation following small bowel transplantation.

Recent reports indicate that epidermal growth factor (EGF) plays a crucial role for graft adaptation in rat model of small bowel transplantation (SBT). The administration of EGF enhances intestinal cell proliferating rate and the recovery of mucosal structure. However, the effect of EGF on biological functions including glucose absorption in intestinal graft remains to be elucidated. SBT was performed in the two-step procedure. On the first step, intestinal graft (30-cm jejunum) from Brown Norway rats was exteriorized through abdominal wall as a Thiry-Vella loop in recipient Lewis rats for one week. On the second surgery (POD 7), recipient jejunum was replaced orthotopically by the graft, and transplanted rats were treated intraperitoneally with EGF or its vehicle for 3 days. Analyses of histology and biological functions in the graft were done at POD 14. EGF increased both levels of villus height and crypt depth in the graft of transplanted groups. EGF enhanced the glucose absorption as well as the induction of sodium glucose cotransporter 2- to 3-fold in transplanted groups. Further, EGF stimulated the activities of disaccharidase (maltase and sucrase) and the induction of dipeptide cotransporter. These results demonstrate that EGF enhances the structural and functional adaptation of intestinal grafts after SBT. EGF may be useful therapy for patients following intestinal transplantation.

Adaptation, Physiological↗
PubMed2004

Epidermal growth factor and interleukin-1beta synergistically stimulate the production of nitric oxide in rat intestinal epithelial cells.

Epidermal growth factor (EGF) is one of the trophic factors for intestinal adaptation after small bowel transplantation (SBT). A recent report indicates that nitric oxide (NO) has cytoprotective effects on bacterial translocation (BT) after SBT. We hypothesized that EGF stimulates the expression of the inducible NO synthase (iNOS) gene in the graft after SBT, followed by increased production of NO, resulting in the decrease of BT. Intestinal epithelial cells (IEC)-6 were treated with EGF and/or IL-1beta in the presence and absence of phosphatidylinositol 3-kinase (PI3-kinase) and EGF receptor kinase inhibitors (LY-294002 and tyrphostin A25). The induction of NO production and iNOS and its signal molecules, including the inhibitory protein of NF-kappaB (IkappaB), NF-kappaB, and Akt, were analyzed. IL-1beta stimulated the degradation of IkappaB and the activation of NF-kappaB but had no effect on iNOS induction. EGF, which had no effect on the NF-kappaB activation and iNOS induction, stimulated the upregulation of type 1 IL-1 receptor (IL-1R1) through PI3-kinase/Akt. Simultaneous addition of EGF and IL-1beta stimulated synergistically the induction of iNOS, leading to the increased production of NO. Our results indicate that EGF and IL-1beta stimulate two essential signals for iNOS induction in IEC-6 cells: the upregulation of IL-1R1 through PI3-kinase/Akt and the activation of NF-kappaB through IkappaB kinase, respectively. Simultaneous addition of EGF and IL-1beta can enhance the production of NO, which may contribute to the cytoprotective effect of EGF against intestinal injury.

Animals↗
PubMed2003

Transmesenteric hernia: report of two patients with diagnostic emphasis on plain abdominal X-ray findings.

UNLABELLED: Transmesenteric hernia is a rare cause of small bowel obstruction and is seldom diagnosed preoperatively, partly because of unfamiliarity with this type of internal hernia. The clinical symptoms of internal hernia may be intermittent and nonspecific, making the diagnosis extremely difficult. We report two patients, 7- and 5-year-old girls, with mesenteric hernia of the ileum. Because of the difficulty of clinical diagnosis of internal hernia, imaging studies played a crucial role. We would like to stress the importance of plain radiological findings as diagnostic aids. CONCLUSION: a consistent intestinal gas imaging after some interval suggests the possibility of an internal hernia, especially accompanied with a circular or oval defect of the gas shadows in the middle of the abdomen. A serial abdominal X-ray study can be helpful in the diagnosis of internal hernia.

Child↗
PubMed2003

Congenital dilatation of the bile duct: changes in diagnostic tools over the past 19 years.

BACKGROUND: Because of recent improvements in diagnostic procedures, many cases of congenital dilatation of the bile duct (CDBD) have been diagnosed in early life. To determine the mode of presentation and changes in diagnostic tools, medical records of 34 children (25 girls, nine boys) with CDBD who were treated between 1982 and 2000 were reviewed. RESULTS: The age at presentation ranged from 0 to 16 years (median 4.9 +/- 0.7 years), with two patients being diagnosed using prenatal ultrasonography. Of the 32 patients diagnosed post-natally, 21 (66%) complained of abdominal pain. There were also 21 (66%) cases of vomiting. Sixteen patients (50%) experienced both these symptoms. Ten (31%) cases presented with jaundice and three (9%) presented with a palpable mass. Ultrasonography was used as a diagnostic tool in 29 cases (85%). The finding of a dilated common bile duct on abdominal ultrasonography was helpful for early diagnosis. Spiral computed tomography was also a useful and accurate imaging method for diagnosis. Anomalous pancreaticobiliary junction (PBJ) was demonstrated in 44% of patients with CDBD. Magnetic resonance cholangiopancreatography, which can be performed non-invasively, is useful for the diagnosis and pre-operative assessment of CDBD in children. The average length of time from presentation to diagnosis could be shortened from 46 days (1982-1988) to 13 days (1995-2000). CONCLUSION: Recent improvements in diagnostic procedures make immediate, non-invasive diagnosis of CDBD and PBJ possible.

Adolescent↗
PubMed2002

Effect of epidermal growth factor on intestinal adaptation after allogeneic small bowel transplantation in rats.

We reported that epidermal growth factor (EGF) stimulated graft adaptation in a rat model of syngeneic small bowel transplantation. However, graft rejection is a severe problem with clinical small bowel transplantation, because small intestinal wall contains large amounts of lymphoid tissue. Studies were performed to investigate the effect of EGF on allogeneic graft adaptation after small bowel transplantation in rats treated with an immunosuppressant FK506. The transplanted animals received intraperitoneally EGF or saline (untreated) after surgery and were examined for analysis one week later. EGF-treated group markedly enhanced the water absorption and induction of sodium glucose cotransporter (SGLTI) as compared with EGF-untreated group. EGF-treated group also increased the mucosal crypt depth and its cell proliferating rate, although there was no significant difference in the mucosal villus height between the two groups. These results indicate that EGF accelerates intestinal allograft adaptation in part by the recovery of mucosal structure and function after small bowel transplantation in rats. EGF may have relevance to promote graft function in clinical small intestinal transplantation.

Adaptation, Physiological↗
PubMed2002

[A case of postoperative liver metastasis from gastric cancer which responded well to weekly chemotherapy with paclitaxel].

We report a case of postoperative liver metastasis from gastric cancer showing a remarkable response to weekly administration of paclitaxel (TXL). The patient was a 50-year-old woman who underwent total gastrectomy. One month later, liver metastasis and a small amount of ascites were detected by CT scan. Therefore, the patient was administered weekly TXL. TXL (80 mg/m2) was infused over 1 hour after short premedication on an outpatient basis. Administration was continued for 3 weeks followed by 1 week rest. Liver metastasis and ascites disappeared 3 months after administration. The toxic events were leukopenia (grade 1) and alopecia (grade 1). No major adverse effects were observed.

Antineoplastic Agents, Phytogenic↗