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Biomedical subjects

J M Seo

Publications and source records attributed to J M Seo.

11 recordsLinked to original sources

Atomic structures of benzene and pyridine on Si(5 5 12)-2 x 1.

The adsorption structures of benzene and pyridine on Si(5 5 12)-2 x 1 were studied at 80 K by using a low-temperature scanning tunneling microscope and density functional theory calculations. These structures are different from those observed on low-index Si surfaces: benzene molecules exclusively bind to two adatoms, that is, with di-sigma bonds between carbon atoms and silicon adatoms, leading to the loss of benzene aromaticity; in contrast, pyridine molecules interact with adatom(s) through either Si-N dative bonding or di-sigma bonds. Dative bonding configurations with pyridine aromaticity are the dominant adsorption features and are more stable than di-sigma bonding configurations. Thus the dative bonding of nitrogen-containing heteroaromatic molecules provides a strategy for the controlled attachment of aromatic molecules to high-index surfaces.

Adsorption↗

A case of laryngeal posttransplantation lymphoproliferative disease.

The development of posttransplant lymphoproliferative disease (PTLD) is strongly linked to infection with the Epstein-Barr virus (EBV), immunosuppression-state, the type of allograft, and EBV-seronegativity. A 18-month-old girl who had undergone living donor liver transplantation using the left lateral segment from her father was treated with tacrolimus and corticosteroid as an immunosuppressant regimen. She was readmitted 3 months after the transplant to evaluate the etiology of dyspnea and abdominal fullness as well as a decreased urine volume. She was diagnosed as an anastomotic stenosis of the hepatic vein for which she underwent balloon angioplasty. The treatment was repeated at postoperative month 5, 8, and 11. As postoperative 6 months, the result of the serological EBV-CA (IgG/IgM) was positive. In postoperative month 10, the EBV PCR serologic test become positive, and a laryngeal biopsy revealed PTLD. She was treated with acyclovir and gangyclovir as well as reduced immunosuppression. We report herein a rare case of laryngeal PTLD in a patient who had undergone living donor liver transplant with paternal allograft.

Female↗

Case of living donor liver transplantation in a patient with biliary atresia combined with situs inversus.

Until recently, situs inversus was considered to be an absolute contraindication for liver transplantation. However, recent reports have suggested that situs inversus should not be considered a contraindication. This study presents a successful living donor liver transplantation performed in a 4-month-old male infant with biliary atresia and situs inversus. The surgical findings revealed abdominal situs inversus with polysplenia and an absent retrohepatic inferior vena cava and intestinal malrotation.

Adult↗

Posttransplantation lymphoproliferative disorder in pediatric liver transplantation.

INTRODUCTION: The aim of this study was to evaluate the clinical features of risk factors for posttransplantation lymphoproliferative disorder (PTLD) in pediatric liver transplantation. MATERIALS AND METHODS: Between June 1996 and June 2002, among 41 pediatric patients who underwent liver transplantation, 7 died in the postoperative period. Thirty-five patients, including 1 patient who died of PTLD, were reviewed. Based on the serology results, patients were divided into a high-risk group (EBV-naive recipients of EBV-positive grafts) and a low-risk group (patients other than those in the high-risk group). RESULTS: Five of 41 patients (12.2%) developed PTLD. All of them belonged to the high-risk group. The incidence of PTLD in the high-risk group was 31.3% (5 of 16). The mean duration between operation and diagnosis for PTLD was 9.8 months. Primary EBV infection developed at a median of 6 months after transplantation. Three of 5 patients developed rejection before the diagnosis of PTLD. One patient was diagnosed with laryngeal and gastrointestinal PTLD, whereas the other 4 had gastrointestinal PTLD. They experienced the following symptoms and signs: anemia (100%), hypoalbuminemia (100%), fever (80%), diarrhea (80%), gastrointestinal bleeding (80%), and anorexia (60%). CONCLUSION: The common features of PTLD development were as follows: (1) EBV-positive donors placed into EBV-naive recipients, (2) primary EBV infection approximately 6 months after transplantation, (3) young age, 1 year old at operation, and (4) requirement for intensive posttransplantation immunosuppression.

Child↗

Prevention of de novo hepatitis B infection from HbcAb-positive donors in living donor liver transplantation.

Hepatitis B virus (HBV) prophylaxis is necessary to prevent de novo hepatitis B infection from HbcAb-positive donors. However, which protocol is more effective is somewhat controversial. Also, it is uncertain whether it is necessary to administer HBV prophylaxis for HbsAb-positive recipients. This study attempted to determine whether it is necessary to administer HBV prophylaxis for HbsAb-positive patients and to evaluate the efficacy of an HBIG monotherapy protocol. From May 1996 to July 2001, among 128 donors examined for HbcAb, 58 donors (45.3%) were HbcAb-positive. Eighteen HbcAb-positive grafts were transplanted to HbsAg-negative recipients. The 4 patients who died of unrelated causes were excluded from this study. Of 14 study cases, 12 recipients were HbsAb-positive, and 2 were HbsAb-naive. Prior to late 1998, we used HBV vaccination only for de novo infection prophylaxis. However, starting from December 1998, HBIG was administered from the time of the liver transplantation regardless of HBsAb positivity. The overall rate of de novo HBV infections from HbcAb-positive donors was 21.4% (3 of 14). All 3 recipients without HBIG prophylaxis presented with de novo HBV infections. Two were HbsAb-positive preoperatively. No de novo HBV infections occurred among recipients with HBIG prophylaxis. Therefore, it is essential to administer HBV prophylaxis even for vaccinated HbsAb-positive patients. HBIG monotherapy is effective to prevent de novo hepatitis B infections from HbcAb-positive donors in living donor liver transplantation.

Child↗

The number of CD8+ T cells and NKT cells increases in the aqueous humor of patients with Behçet's uveitis.

To determine whether there are differences in the immunopathogenesis of different endogenous uveitis syndromes, the phenotypic characteristics of immune cells were analysed among patients with endogenous uveitis. The aetiology of the uveitis included idiopathic recurrent acute anterior uveitis (18 patients), idiopathic intermediate uveitis (13 patients), Behçet's uveitis (17 patients), Vogt-Koyanagi-Harada syndrome (7 patients), and so on. Flow cytometric analysis was performed using immune cells of the aqueous humor and the peripheral blood during the active phase of intraocular inflammation, and monoclonal antibodies to CD3, CD4, CD8, CD14, CD19, CD56, TCR gammadelta, pan TCR alphabeta and Valpha24. CD8+ T cells were predominant in the aqueous humor of the patients with Behçet's uveitis, whereas CD4+ T cells were mainly found in the aqueous humor of patients other than those with Behçet's uveitis. The number of NKT (CD3+CD56+) cells was significantly higher both in the aqueous humor and the peripheral blood of the patients with Behçet's uveitis compared with the other groups (P < 0.05). CD8+CD56+ cells were the predominant subtype of the increased NKT cells in patients with Behçet's uveitis. In addition, intraocular infiltration of CD14+ cells significantly differed among the uveitis patients (P < 0.05). These results suggest that the immunopathogenesis of endogenous uveitis can vary between syndromes, and that CD8+CD56+ NKT cells may play an important role in the immunopathogenesis of Behçet's uveitis.

Adolescent↗

Alterations in hepatic metabolism of sulfur-containing amino acids induced by ethanol in rats.

Alterations in hepatic metabolism of S-amino acids were monitored over one week in male rats treated with a single dose of ethanol (3 g/kg, ip). Methionine and S-adenosylhomocysteine concentrations were increased rapidly, but S-adenosylmethionine, cysteine, and glutathione (GSH) decreased following ethanol administration. Activities of methionine adenosyltransferase, cystathionine gamma-lyase and cystathionine beta-synthase were all inhibited. gamma-Glutamylcysteine synthetase activity was increased from t = 8 hr, but GSH level did not return to control for 24 hr. Hepatic hypotaurine and taurine levels were elevated immediately, but reduced below control in 18 hr. Changes in serum and urinary taurine levels were consistent with results observed in liver. Cysteine dioxygenase activity was increased rapidly, but declined from t = 24 hr. The results show that a single dose of ethanol induces profound changes in hepatic S-amino acid metabolism, some of which persist for several days. Ethanol not only inhibits the cysteine synthesis but suppresses the cysteine availability further by enhancing its irreversible catabolism to taurine, which would play a significant role in the depletion of hepatic GSH.

Amino Acids, Sulfur↗

Cloning of cDNA for a novel fibrinogen/angiopoietin-related protein, FARP.

Using a low abundant gene screening strategy in the human dermal papilla cell cDNA library, we isolated a novel cDNA, which was 1,872 bp of nucleotides in length and contained an open reading frame encoding 405 amino acids. We designated it 'fibrinogen/angiopoietin-related protein' (FARP) as it contained the characteristic coiled-coil domain and fibrinogen-like domain in the NH2- and COOH-terminal, which are conserved in angiopoietins. FARP has a highly hydrophobic region at the N-terminus that is typical of a secretory signal sequence. Recently, a very similar gene, HFARP, was cloned and they have a difference of only 18 amino acids in N-terminus. While HFARP was expressed only in the liver, northern blot analysis showed that FARP mRNA is abundantly expressed in the liver, placenta, prostate, and ovary in human adult tissues. It was also expressed in the fetal liver and lung carcinoma cell line. Further study will be needed to clarify the function of the FARP gene.

Angiopoietin-Like Protein 4↗

Hepatocellular carcinoma with lung metastasis in a 9-year-old-boy.

Hepatocellular carcinoma (HCC) remains chemoresistant and, therefore, the principal treatment of HCC is surgical resection. After a 9-year-old boy with huge HCC with lung metastasis received the 5 cycles of chemotherapy (cisplatin and Adriamycin), the lung metastasis had been resolved completely and the size of HCC in liver had decreased. Right hepatic trisegmentectomy was performed, and then the additional 3 cycles of chemotherapy was given. Currently, the patient shows no recurrence of HCC 42 months after surgical extirpation.

Carcinoma, Hepatocellular↗

Current concepts in lymphatic malformation.

A lymphatic malformation (LM) is the most common form of congenital vascular malformation (CVM). The new Hamburg classification of CVM distinguishes the truncular (T) form from the extratruncular (ET) form of LMs. Both are consequences of a developmental arrest at the different stages of lymphangiogenesis as a result of defective genes. The purpose of this review was to evaluate the current management results of both forms of LMs. A retrospective review of the clinical data of 315 patients with a diagnosis of LMs treated between September 1994 and December 2001 was performed. Lymphoscintigraphy was the most frequent diagnostic test. The patients with the ET form were treated with sclerotherapy with OK-432 and/or ethanol. Combinations of CDP (complex decongestive physiotherapy) and/or compressotherapy were used to treat all the T-form patients. In addition, surgery, either reconstructive or ablative, was offered to patients with the T form who failed to respond to the proper CDP. A multidisciplinary team performed the management of LM, and the results were evaluated every 6 months. Among 797 patients with CVM, 315 were confirmed to have LMs, either as the T form (226) or the ET form (89). Another 66 LMs were diagnosed with hemolymphatic malformations (HLM). Most of the ET forms (89/315) were the cystic type (70/89), while the T forms included aplasia and/or an obstruction (204/226). The ET form was most frequent in the head, neck, and thorax (69/89). The T form was located most frequently to the extremities (202/226), mostly to the lower limb (180/202). Two hundred and twenty-six T forms belonged to the various clinical stages: stages I-32, II-104, III-48, IV-18, and an unclear stage-24. The ET form was treated with sclerotherapy using OK-432 (108/120) and absolute ethanol (12/120). Among the 11 patients with the multiple ET form, 7 patients underwent perioperative sclerotherapy with OK-432 and a subsequent surgical excision. The clinical response of the T form at the extremity to CDP was excellent to good in a majority of clinical stages I to II (121/136) but decreased to a good to fair degree in stages III to IV (31/66). The additional surgical therapy, either reconstructive (10/19) or ablative (9/19), provided limited success in improving CDP efficacy, owing mainly to poor compliance. The long-term outcome of the initial success through self-motivated home-maintenance care during the follow-up period of up to 48 months was totally dependent on patient compliance. OK-432 sclerotherapy to 51 ET forms has shown excellent results on 88.9% of the cystic type (40/45) and 50% (3/6) of the cavernous type (minimum follow-up for 24 months). Seventeen ET forms in 7 patients were treated with a preoperative OK-432 sclerotherapy and a subsequent surgical excision, which provided good to excellent results in 14 for a minimum of 24 months. Primary lymphedema, which is the T form of LMs, can be managed safely by a combination of CDP with compressotherapy. Patients with good compliance can benefit from additional surgical therapy, either reconstructive or ablative. The ET form, particularly the cystic type, can be treated with various scleroagents that are preferably less toxic as the primary therapy. A surgical excision with or without perioperative sclerotherapy provides good results for patients with the localized cavernous type of the ET form. A multidisciplinary team approach is essential for the proper care of LM.

Adolescent↗