Biomedical subjects

Jung-Tak Oh

Publications and source records attributed to Jung-Tak Oh.

11 recordsLinked to original sources

PubMed2006

Urachal anomalies in children: a single center experience.

The objective of this study is to define optimal diagnosis and treatment strategies for patients with urachal anomalies in the pediatric age group. The medical records of 21 children who had undergone surgery for urachal anomalies at Severance Hospital, Yonsei University College of Medicine from January 1990 to April 2005 were reviewed. The subjects included 14 males and 7 females (M:F 2:1). The four types of urachal anomalies confirmed were a urachal cyst in 10 patients (47.6%), a patent urachus in 6 (28.6%), a urachal sinus in 4 (19.0%) and a urachal diverticulum in 1 (4.8%) patient. The most common presenting complaint was umbilical discharge (n = 10, 40.0%), followed by abdominal mass (n = 9, 36.0%). Urachal anomalies were diagnosed by ultrasonography in 18 patients, and 7 of them were additionally examined by computed tomography. The remaining patients were diagnosed solely by surgical exploration. Excision was performed in all patients and was supplemented by partial cystectomy in three. Umbilical discharge was the most common clinical manifestation in our patients, suggesting that ultrasonography should be performed in patients with umbilical discharge to differentiate urachal anomalies. We found the most common anomaly to be the urachal cyst, and all patients were successfully treated by surgical excision.

Child↗

PubMed2006

Diaphragmatic repair through fetal tissue engineering: a comparison between mesenchymal amniocyte- and myoblast-based constructs.

PURPOSE: We have previously shown that fetal tissue engineering is a preferred alternative to diaphragmatic repair in a large animal model. This study was aimed at comparing diaphragmatic constructs seeded with mesenchymal amniocytes and fetal myoblasts in this model. METHODS: Neonatal lambs (n = 14) underwent repair of an experimental diaphragmatic defect with identical scaffolds, either seeded with labeled autologous cells (mesenchymal amniocytes in group 1 and fetal myoblasts in group 2) or as an acellular graft (group 3). At 1 to 12 months postoperatively, implants were harvested for multiple analyses. RESULTS: Repair failure (reherniation or eventration) was significantly higher in group 3 than in groups 1 and 2, with no difference between groups 1 and 2. Seeded fetal myoblasts quickly lost their myogenic phenotype in vivo. All grafts contained cells with a fibroblastic-myofibroblastic profile. Elastin concentrations and both modular and ultimate tensile strengths were significantly higher in group 1 than in groups 2 and 3. There were no differences in glycosaminoglycans and type I collagen levels among the groups. CONCLUSIONS: Diaphragmatic repair with a mesenchymal amniocyte-based engineered tendon leads to improved structural outcomes when compared with equivalent fetal myoblast-based and acellular grafts. The amniotic fluid is a preferred cell source for tissue-engineered diaphragmatic reconstruction.

Animals↗

PubMed2006

Serial transverse enteroplasty enhances intestinal function in a model of short bowel syndrome.

UNLABELLED: OBJECTIVE/SUMMARY BACKGROUND DATA: Serial transverse enteroplasty (STEP) is a new intestinal lengthening procedure that has been shown to clinically increase bowel length. This study examined the impact of the STEP procedure upon intestinal function in a model of short bowel syndrome. METHODS: Young pigs (n=10) had a reversed segment of bowel interposed to induce bowel dilatation. Five pigs underwent a 90% bowel resection with a STEP procedure on the remaining dilated bowel while 5 served as controls and had a 90% bowel resection without a STEP procedure. Determinations of nutritional status, absorptive capacity, and bacterial overgrowth were conducted 6 weeks after resection. Statistical comparisons were made by 2-sample t test (significance at P<0.05). RESULTS: The STEP procedure lengthened the bowel from 105.2+/-7.7 cm to 152.2+/-8.3 cm (P<0.01). The STEP animals showed improved weight retention compared with controls (mean, -0.5%+/-1.8% body weight versus -17.6%+/-1.5%, P<0.001). Intestinal carbohydrate absorption, as measured by d-Xylose absorption and fat absorptive capacity as measured by serum vitamin D and triglyceride levels, were increased in the STEP group versus controls. Serum citrulline, a marker of intestinal mucosal mass, was significantly elevated in the STEP pigs compared with controls. None of the STEP animals but 4 of 5 control animals were noted to have gram-negative bacterial overgrowth in the proximal bowel. CONCLUSIONS: STEP improves weight retention, nutritional status, intestinal absorptive capacity, and serum citrulline levels in a porcine short bowel model. A salutary effect upon bacterial overgrowth was also noted. These data support the use of this operation in short bowel syndrome.

Anastomosis, Surgical↗

PubMed2005

Solid-pseudopapillary tumours of the pancreas: 14 years experience.

BACKGROUND: Solid-pseudopapillary tumour of the pancreas (SPTP) is a low-grade malignancy lesion that is distinct from other pancreatic tumours. Preoperative diagnosis is often inaccurate and treatment strategies remain controversial. The present study reviews the clinical features, diagnosis, treatment, and outcome of Asian patients with SPTP from a single institution. METHODS: The medical records and images of patients who underwent surgery for SPTP between June 1990 and December 2003 were retrospectively reviewed. Study eligibility required that patients had undergone surgical resections and that the SPTP had been pathologically demonstrated. RESULTS: Twenty-eight patients with SPTP were identified. Eighteen patients (64.3%) reported the predominant symptom of 'vague abdominal pain', five patients (17.8%) had an apparent 'abdominal mass', and five patients (17.8%) without overt symptoms had masses that were discovered incidentally during screening. All patients underwent magnetic resonance (MR) imaging (n = 22) and/or computed tomography (n = 17), with a specificity of 90.9% and 76.4%, respectively. All masses were well-circumscribed, except for a tumour in one patient (3.6%), which adhered to the stomach wall and metastasized to the liver. Two patients (7.1%) underwent enucleation, while 25 patients (89.3%) received curative resection. The patient with the liver metastases underwent distal pancreatectomy and splenectomy with partial hepatectomy. The mean follow up was 66.9 months. No mortality occurred during follow up but the patient with the liver metastasis had progressive deterioration. CONCLUSION: Symptoms of SPTP are indistinct and preoperative diagnosis is often inaccurate. Magnetic resonance imaging improves SPTP diagnosis. In general, the prognosis of well-circumscribed SPTP is favourable after curative resection.

Adolescent↗

PubMed2004

Giant Meckel's diverticulum associated with a congenital diaphragmatic hernia.

Giant Meckel's diverticulum is a very rare lesion and its association with a congenital diaphragmatic hernia has not been reported previously. We report a case of newborn with a giant Meckel's diverticulum and congenital diaphragmatic hernia. A large round atypical air-filled bowel segment was found by chest radiography preoperatively, and a giant Meckel's diverticulum was located within the left hemithorax during surgery.

Hernia, Diaphragmatic↗

PubMed2004

Diaphragmatic reconstruction with autologous tendon engineered from mesenchymal amniocytes.

PURPOSE: This study examined the effects of amniocyte-based engineered tendons on partial diaphragmatic replacement. METHODS: Ovine mesenchymal amniocytes were labeled with green fluorescent protein (GFP), expanded, and seeded into a collagen hydrogel. Composite grafts (20 to 25 cm2) based on acellular dermis (group I), or acellular small intestinal submucosa (group II) received either a cell-seeded or an acellular hydrogel within their layers. Newborn lambs (n = 20) underwent partial diaphragmatic replacement with either an acellular or a cellular autologous construct from either group. At 3 to 12 months' postoperatively, implants were subjected to multiple analyses. RESULTS: Diaphragmatic hernia recurrence was significantly higher in animals with acellular grafts (5 of 5) then in animals with cellular ones (1 of 4) in group I (P <.05) but not in group II (3 of 6 and 4 of 5, respectively). Cellular grafts had higher modular (5.27 +/- 1.98 v. 1.27 +/- 0.38 MPa) and ultimate (1.94 +/- 0.70 v. 0.29 +/- 0.05 MPa) tensile strength than acellular implants in group I (P <.05), but not in group II. Quantitative analyses showed no differences in extracellular matrix components between cellular and acellular implants in either group. All cellular implants showed GFP-positive cells. CONCLUSIONS: Diaphragmatic repair with an autologous tendon engineered from mesenchymal amniocytes leads to improved mechanical and functional outcomes when compared with an equivalent acellular bioprosthetic repair, depending on scaffold composition. The amniotic fluid may be a preferred cell source for engineered diaphragmatic reconstruction.

Amniotic Fluid↗

PubMed2003

A comprehensive karyotypic analysis on Korean hepatocellular carcinoma cell lines by cross-species color banding and comparative genomic hybridization.

Chromosomal aberrations were investigated in hepatitis B virus integrated into the hepatocellular carcinoma (HCC) cell lines SNU-368, SNU-449, SNU-398, SNU-182, and SNU-475 using Giemsa-banding, cross species color banding, and comparative genomic hybridization (CGH). The origins of the marker chromosomes were confirmed by fluorescence in situ hybridization with constructed chromosome painting probes. Each cell line had unique modal karyotypic characteristics and showed variable numbers of numerical and structural clonal cytogenetic aberrations. The gains were commonly detected on chromosome 1, and chromosome regions 6p, 7q, 8q, 10p, 17q, and 20; the losses were often found on 4q21 approximately qter, 13, 18q21 approximately qter, and Y. In particular, the breakpoints on 1p36, 1p13 approximately q21, 2p13 approximately q11, 6q10 approximately q11, 7q11, 7q22, 14q10, 16q10 approximately q13, 17q21, 18q21, and 19p11 approximately q11 were involved frequently at the multiple rearranged lesions. CGH analysis further confirmed the cytogenetic data, and the nonrandom rearrangements data suggested the candidate regions for the genes to be isolated which were related to HCC.

Carcinoma, Hepatocellular↗

PubMed2003

Serial transverse enteroplasty (STEP): a novel bowel lengthening procedure.

BACKGROUND/PURPOSE: Bowel lengthening may be beneficial for children with short bowel syndrome. However, current techniques require at least one intestinal anastomosis and place the mesenteric blood supply at risk. This study seeks to establish the technical principles of a new, simple, and potentially safer bowel lengthening procedure. METHODS: Young pigs (n = 6) underwent interposition of a reversed intestinal segment to produce proximal small bowel dilation. Five weeks later the reversed segment was resected. Lengthening of the dilated bowel then was performed by serial transverse applications of a GIA stapler, from opposite directions, to create a zig zag channel. A distal segment of equal length served as an in situ morphometric control. Contrast radiologic studies were performed 6 weeks later, and the animals were killed. Statistical comparisons were made by paired t test with P less than.05 considered significant. RESULTS: After bowel lengthening, all animals gained weight (66.7 +/- 3.0 [SD] kg v 42.5 +/- 3.5 kg; P <.001) and showed no clinical or radiologic evidence of intestinal obstruction. Intraoperatively, immediately after serial transverse enteroplasty, the intestine was substantially elongated (82.8 +/- 6.7 cm v 49.2 +/- 2 cm; P <.01). Six weeks after surgery, the lengthened intestinal segment became practically straight and, compared with the in situ control, remained significantly longer (80.7 +/- 13.1 cm v 57.2 +/- 10.4 cm; P <.01). There was no difference in diameter between these segments (4.3 +/- 0.7 cm v 3.8 +/- 0.4 cm; P value, not significant). CONCLUSIONS: Serial transverse enteroplasty (STEP) significantly increases intestinal length without any evidence of obstruction. This procedure may be a safe and facile alternative for intestinal lengthening in children with short bowel syndrome.

Anastomosis, Surgical↗

PubMed2002

The placenta as a cell source in fetal tissue engineering.

PURPOSE: This study was aimed at determining whether fetal tissue constructs can be engineered from cells derived from the placenta. METHODS: A subpopulation of morphologically distinct cells was isolated mechanically from specimens of human placenta (n = 6) and selectively expanded. The lineage of these cells was determined by immunofluorescent staining against multiple intermediate filaments and surface antigens. Cell proliferation rates were determined by oxidation assays and compared with those of immunocytochemically identical cells derived from human amniotic fluid samples (n = 6). Statistical analysis was by analysis of variance (ANOVA). After expansion, the cells were seeded onto a polyglycolic acid polymer/poly-4-hydroxybutyrate scaffold. The resulting construct was analyzed by both optical and scanning electron microscopy. RESULTS: The immunocytochemical profile of expanded placental cells was consistent with a nontrophoblastic, mesenchymal origin. Their proliferation rate in culture was not significantly different when compared with mesenchymal fetal cells isolated from human amniotic fluid; however, it was greater than previously reported rates for similar cells obtained from postnatal or adult tissues. Construct analysis showed dense layers of cells firmly attached to the scaffold without evidence of cell death. CONCLUSIONS: Subpopulations of nontrophoblastic, mesenchymal cells can be isolated consistently from the human placenta. These cells proliferate as rapidly as fetal mesenchymal amniocytes in vitro and attach firmly to polyglycolic acid scaffolds. The placenta can be a valuable and practical source of cells for the engineering of select fetal tissue constructs.

Cells, Cultured↗

PubMed2002

Using MR cholangiopancreatography to reveal anomalous pancreaticobiliary ductal union in infants and children with choledochal cysts.

OBJECTIVE: The purpose of this study was to determine whether MR cholangiopancreatography can accurately depict anomalous pancreaticobiliary ductal union in children with choledochal cysts. SUBJECTS AND METHODS: Twenty children (age range, 1 month-13 years; mean age, 4.6 years; all girls) who were diagnosed with choledochal cyst by sonography underwent MR cholangiopancreatography with a single-shot fast spin-echo sequence. The type of choledochal cyst and anomalous pancreaticobiliary ductal union were characterized on the basis of MR cholangiopancreatographic findings and were compared with the finding of intraoperative cholangiography. RESULTS: The type of choledochal cyst (type Ia, n = 4; type Ic, n = 7; type IVa, n = 7; type IVb, n = 2) determined on MR cholangiopancreatography correlated with that identified on intraoperative cholangiography in each patient. Anomalous pancreaticobiliary ductal union was detected by MR cholangiopancreatography and intraoperative cholangiography in 12 (60%) and 16 (80%) of 20 patients, respectively. The types of anomalous pancreaticobiliary ductal union as determined on MR cholangiopancreatography (type A, n = 2; type B, n = 7; type C, n = 3) were concordant with those of intraoperative cholangiography in 11 of 12 patients. In five of eight patients with choledochal cyst (type Ia, n = 1; type IVa, n = 5; type IVb, n = 2) in whom MR cholangiopancreatography could not depict anomalous pancreaticobiliary ductal union, anomalous pancreaticobiliary ductal union was documented on intraoperative cholangiography that was performed after choledochal cyst resection. CONCLUSION: MR cholangiopancreatography provides diagnostic information about anomalous pancreaticobiliary ductal union in children with choledochal cyst.

Adolescent↗

PubMed2002

Measles-related appendicitis.

Owing to the characteristic Warthin-Finkeldey giant cells found in hyperplastic mucosa-associated lymphoid tissue, it has been emphasized that pathologists can make a diagnosis of measles from appendectomy specimens even in the prodromal stage before diagnostic rashes develop. However, to date, those reported cases of measles-related appendicitis have dealt with the histologic features of the prodromal stage and we found no reports in the English literature describing the histopathologic findings of appendicitis during the full-blown stage of measles. Here, we describe 2 cases of measles-related appendicitis that show contrasting histologic features according to stage, one discovered during the prodromal stage and the other occurring during the full-blown stage. This report describes heretofore unreported histopathologic findings of measles-related appendicitis observed during the full-blown stage of the infection and highlights histopathologic changes caused by replication of the virus in different compartments of the same organ during the course of infection.

Appendicitis↗