PubMed Health⌕ Search

Biomedical subjects

S H Choi

Publications and source records attributed to S H Choi.

At least 37 records · Page 2Linked to original sources
PubMed2004

Topography of the outer mandibular symphyseal region with reference to the autogenous bone graft.

The mandibular symphysis is preferred as a donor site for the relatively small grafts needed for the autogeneous bone graft procedure. This study was undertaken to determine the morphology and composition of the cortical and trabecular bone in the mandibular symphyseal region using 35 mandible specimens from Koreans. The topographical patterns through the thickness of the cortical plate and the width of the trabecular bone were observed. In this study, the labial cortical plate of the mandible became thicker from the superior to the inferior aspects (P < 0.05). However, the trabecular bone width exhibited a different distribution pattern compared to the thickness of the labial cortical plate. This observation concerning the cortical and trabecular bones assists in determination of the depth of osteotomy. The results provide useful information on the mandibular symphysis graft prior to dental implant placement. These results will enable the volume of the cortical plate in the mandibular symphyseal region and its proper size, depth, and location to be predicted when removing a graft block.

Alveolar Process↗
PubMed2004

Neuropeptide Y immunoreactivity and corticotropin-releasing hormone mRNA level are increased in the hypothalamus of mouse bearing a human oral squamous cell carcinoma.

We examined gene expression of corticotropin-releasing hormone and neuropeptide Y level in the hypothalamic paraventricular nucleus of mouse bearing a human oral squamous cell carcinoma. A cell line derived from a human oral squamous cell carcinoma was inoculated into the lower dorsal area of nude mice. Body weight, tumor size and daily food intake were recorded every morning. Mice were sacrificed for corticotropin-releasing hormone mRNA in situ hybridization and neuropeptide Y immunohistochemistry, when the tumor ratio reached to 11-13% of real body weight. The results were compared with the age-matching non-tumor controls injected with saline instead of carcinoma cell. Body weight gain was significantly reduced in tumor bearing mice, however, no compensatory hyperphagia was found, i.e. daily food intake of the tumor mice did not differ from the non-tumor mice. Both neuropeptide Y immunoreactivity and corticotropin-releasing hormone mRNA level were significantly increased in the hypothalamic paraventricular nucleus of tumor mice. These results suggest that a human oral squamous cell carcinoma may induce anorexia, at least partly, via increasing the hypothalamic expression of corticotropin-releasing hormone in the tumor subjects. Additionally, neuropeptide Y-induced feeding appears to be inhibited in this tumor anorexia model, and this may correlate with increased expression of corticotropin-releasing hormone.

Animals↗
PubMed2004

Auxiliary partial orthotopic liver transplantation in the treatment of acute liver failure: a case report.

A successful experience with auxiliary partial orthotopic liver transplantation (APOLT) for acute liver failure is reported in a 29-year-old woman who experienced jaundice, generalized erythema for 7 days, and decreased mentation for 3 days. Two months prior, she suffered pulmonary tuberculosis, being currently treated with antituberculous medications, which caused the fulminant hepatic failure. We decided to perform APOLT based on two facts. The first was the possibility that the diseased native liver may recover sufficiently to withdraw the immunosuppressants. Second, the pulmonary tuberculosis may have been worsened by immunosuppression. We removed the extended lateral section of the recipient for the graft. The left hepatic vein of the extended left lateral graft was anastomosed to the left hepatic vein of the recipient. The left portal vein of the graft was anastomosed to the left portal vein of the recipient. The right portal vein of the recipient was left without any manipulation. A duct-to-duct anastomosis was performed. On postoperative day 3, antituberculous medications were started. On the postoperative day 37, she was discharged without any problems. On the postoperative day 120, she showed no event of rejection, and her pulmonary symptoms improved. We performed the operation without transection of the portal branch to the native liver, but no functional competition has been discovered.

Adult↗
PubMed2004

Factors affecting graft survival after living donor liver transplantation.

Living donor liver transplantation (LDLT) has been considered as an alternative option to resolve the shortage of cadaveric donor organs, despite the ethical aspects of the donor procedure. The objective of this study was to analyze the risk factors affecting graft survival in LDLT. From June 1996 to December 2002, 141 patients who underwent LDLT were retrospectively analyzed. Graft survival rates were 82.5%, 80%, 77.3%, and 77.3% at 6 months, 1 year, 3 years, and 5 years, respectively. The factors influencing graft survival in univariate analysis were graft-to-recipient body weight ratio (GRWR) less than 0.8% (P = .0009), intraoperative transfusion of more than six packed RBC units in addition to the use of cell saver amounts (P = .0001), left lobe grafts in adults causing small-for-size situations (P = .0135), and donor age (P = .0472). The multivariate analysis demonstrated that GRWR less than 0.8% (P = .002) and intraoperative transfusion of more than six packed RBC units (P = .014) were independent factors that decreased graft survival rates. The graft selection of greater than 0.8% of GRWR and reduction of intraoperative RBC transfusion improve graft survival.

Adolescent↗
PubMed2004

Clinicopathological features of incidental hepatocellular carcinoma in liver transplantation.

The incidence of detecting hepatocellular carcinoma (HCC) in a removed recipient liver after a liver transplant is not rare. The clinical features are expected to be different from the preoperatively diagnosed HCC. The aim of this study was to evaluate the clinicopathological features of incidental HCC. This study retrospectively analyzed five cases of incidental HCC among 51 liver transplant cases of HCC operated from September 1996 to February 2002. The proportion of an incidental HCC was 9.8%. The mean age was 46.2 years with a higher prevalence in may (80%, four cases). The alpha-fetoprotein level was normal or mildly elevated. HBsAg was positive in all cases. Imaging studies revealed regenerative or dysplastic nodules, or no specific lesion. The pathological findings demonstrated a mean size of 1.16 cm, multiplicity in three cases (60%), no microvascular invasion, and Edmonson grade I (60%) and II (40%). There was no recurrence of the HCC. However, two patients died due to an intracranial hemorrhage and a graft failure, respectively. In conclusion, incidentally found HCC showed less invasive pathological features and a better prognosis.

Carcinoma, Hepatocellular↗
PubMed2004

Interpostion vein graft in living donor liver transplantation.

UNLABELLED: In adult-to-adult living donor liver transplantation (LDLT), right lobe grafts without a middle hepatic vein can cause hepatic congestion and disturbance of venous drainage. To solve this problem, various types of interposition vein graft have been used. OBJECTIVES: We used various types of interposition vein grafts for drainage of the paramedian portion of the right lobe in living donor liver transplantation. METHODS: From June 1996 to June 2003, 37 of 176 patients (128 adults, 48 pediatric) who underwent LDLT received vein grafts for drainage of segments V, VIII, or the inferior portion of the right lobe. RESULTS: In 36 adult cases the reconstruction included the inferior mesenteric vein of the donor (n = 14); cadaveric iliac vein stored at cold (4 degrees C) temperature (n = 5); cryopreserved (-180 degrees C) cadaveric iliac vein (n = 10); cryopreserved cadaveric iliac artery (n = 1 case); donor ovarian vein (n = 1); recipient umbilical vein (n = 3); recipient saphenous vein (n = 1); recipient left portal vein (n = 1); recipient left hepatic vein (n = 1). In a pediatric case with malignant hemangioendothelioma that encased and compressed the inferior vena cava, we used an interposition vein graft to replace the inferior vena cava. CONCLUSION: Various types of interposition vein grafts can be used in living donor liver transplantation. Cryopreserved cadaveric iliac vein and artery are useful to solve these drainage problems.

Adult↗
PubMed2004

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↗
PubMed2004

Can we expand the Milan criteria for hepatocellular carcinoma in living donor liver transplantation?

INTRODUCTION: The Milan criteria, namely, tumors 5 cm or less in diameter in patients with single hepatocellular carcinoma (HCC), no more than 3 tumor nodules, and each 3 cm or less in diameter in patients with multiple tumors, are accepted for cadaveric liver allocation. However, in living donor liver transplantation (LDLT), graft donation may only depend on the donor's intention. The aim of this study was to elucidate the feasibility of Milan criteria in LDLT. MATERIALS AND METHODS: From January 2001 to December 2002, 46 cases of liver transplantation (LT) for HCC included 5 hospital mortalities and 3 cadaveric transplantations, all of which were excluded. We classified the patients into Group I cases that met the Milan criteria and Group II cases that did not meet the Milan criteria. The analyses examined tumor-related risk factors affecting recurrence and survival, such as tumor size, number of tumor nodules, and presence of microvascular and macrovascular invasion. RESULTS: Twenty-one cases belonged to Group I and 17 to Group II. There was no significant difference in the recurrence or survival rates between Groups I and II. The risk factors affecting recurrence were macrovascular invasion and tumor size (5 cm). The number of tumor nodules and microvascular invasion did not appear to affect recurrence. The risk factor affecting survival was macrovascular invasion. CONCLUSION: We suggest that in selected cases the Milan criteria could be extended to increase the number of tumor nodules as long as the HCC were small and did not macrovascular invasion.

Cadaver↗
PubMed2004

Small-for-size graft in adult living-donor liver transplantation.

In the era of living donor liver transplantation (LDLT), graft size is related to recipient prognosis. This study was performed to compare the clinical outcomes according to the graft-to-recipient weight ratio (GRWR) in adult LDLT. Seventy-nine adult patients who had undergone LDLT between June 1997 and June 2002 were retrospectively analyzed. The patients were divided into two groups according to the GRWR (group I, GRWR < 0.8%, n = 11; group II, GRWR > or = 0.8%, n = 68). The mean follow-up period was 19.4 (range 1 to 48) months. The recipients were 62 men (78.5%) and 17 women (21.5%) of mean age 45.2 (range 18 to 63) years. The overall patient survival rates were 74.7% at 1 year and 70.7% at 2 years. The patient survival rate in group I was 54.6% at 1 year and 40.9% at 2 years, whereas that in group II was 77.9% at 1 year and 75.3% at 2 years, showing a significant difference (P = .03). There were no significant differences in postoperative total bilirubin, transaminase enzyme level, prothrombin time (INR), portal vein flow on Doppler sonography, amount of ascites through the drain, complications, or acute rejection rates between the two groups. In conclusion, the minimum acceptable graft size in an adult-to-adult LDLT is GRWR of 0.8%. This study suggests that careful postoperative management and/or technical modifications during surgery are necessary, because small-for-size grafts (GRWR < 0.8%) result in lower patient survival rates.

Adult↗
PubMed2004

The influence of lithium fluoride on in vitro biocompatibility and bioactivity of calcium aluminate-pMMA composite cement.

The objective of this study is to assess the influence of lithium fluoride on in vitro biocompatibility and bioactivity of calcium aluminate (CA)-polymethylmethacrylate (PMMA) composite cement exhibiting quick setting time ( < 15 min), low exothermic temperature (< 47 degrees C), and high compressive strength (> 100 MPa). The biocompatibility was measured by examining cytotoxicity tests such as the agar diffusion test with L929 cell line and the hemolysis test with fresh rabbit blood. To estimate the bioactivity of CA-PMMA composite cement, we determined hydroxyapatite (HAp) formation on the surface of composite cement in the simulated body (SBF) solution by using thin-film XRD, XPS, SEM, EPMA and ICP-AES. The results of biocompatibility tests indicated that all experimental compositions of this study had no cytotoxicity and no hemolysis so that there was no cytotoxicity with regard to non-reacted monomers (MMA and TEGDMA) and lithium fluoride. The results of bioactivity tests revealed that CA-PMMA composite cement without lithium fluoride did not form HAp on its surface after 60 days of soaking in the SBF. On the other hand, LiAl2(OH)7 . 2H2O and HAp were formed on the surface of CA-PMMA composite cement including 1.0% by weight of lithium fluoride after 7 and 15 days of soaking in the SBF, respectively. The 5 microm of LiAl2(OH)7 . 2H2O and HAp mixed layers were formed on the surface of specimen after 60 days of soaking in the SBF.

Acrylic Resins↗
PubMed2004

A phase II trial of capecitabine in previously untreated patients with advanced and/or metastatic gastric cancer.

BACKGROUND: Capecitabine (Xeloda) is a novel, oral, selectively tumor-activated fluoropyrimidine with proven activity in the treatment of advanced colorectal cancer. This trial was conducted to evaluate the efficacy, safety and feasibility of capecitabine in previously untreated patients with advanced and/or metastatic gastric cancer, with a view to replacing 5-fluorouracil (5-FU) in such patients. PATIENTS AND METHODS: Forty-four patients received capecitabine 1250 mg/m2 twice daily (2500 mg/m2/day) for 14 days followed by 7 days of rest, for up to six cycles. RESULTS: Capecitabine produced an objective response rate of 34% (all partial responses) and stable disease in 14 patients (30%). The median time to disease progression (TTP) was 3.2 months [95% confidence interval (CI) 2.7-6.4 months] and median overall survival was 9.5 months (95% CI 6.9-13.2 months). Hand-foot syndrome (HFS), nausea, anorexia, diarrhea and vomiting were the most common adverse events. While HFS was the most frequent grade 3/4 toxicity (National Cancer Institute Common Toxicity Criteria), only 9% of patients experienced grade 3 HFS. Severe myelosuppression was not reported during the study. CONCLUSIONS: Capecitabine monotherapy is active and well tolerated as first-line therapy in patients with advanced/metastatic gastric cancer. Larger comparative trials investigating capecitabine-based combination regimens in patients with advanced gastric cancer are warranted.

Administration, Oral↗
PubMed2004

Hepatic bipolar radiofrequency ablation using perfused-cooled electrodes: a comparative study in the ex vivo bovine liver.

The purpose of this paper was to demonstrate the efficacy of the dual probe bipolar radiofrequency (RF) system with the perfused-cooled electrodes inducing coagulation necrosis in the ex vivo bovine liver. The perfused-cooled electrode that allows simultaneous internal cooling and interstitial hypertonic saline perfusion has been developed for RF ablation (RFA). RF was applied to excised bovine liver in a bipolar mode at 150 W using a 200 W generator with two perfused-cooled electrodes for 10 min. After placing the electrodes at 3 cm spacing in the explanted liver, 45 ablation zones were created with three different regimens: Group A, using both intraelectrode cooling and interstitial perfusion; group B, using only the intraelectrode cooling; and group C, using only interstitial perfusion. In groups A and C, RFA was performed with the infusion of 6% hypertonic saline at the rate of 2 ml min(-1). During RFA, we measured the tissue temperature at the midpoint between the two electrodes. The dimensions of the ablation zones and the changes in impedance, currents and liver temperature during RFA were compared in these three groups. The mean tissue impedance during RFA in group A (56.7+/-21.7 Omega) and group C (56.9+/-20.6 Omega) was significantly lower than group B (112+/-19.7 Omega) (p<0.001). The mean current was higher in group A (1765+/-128 mA) than groups B (760+/-321 mA) and C (1298+/-349 mA) (p<0.05). In addition, the shortest vertical diameter of coagulation necrosis was greater in groups A (4.9+/-0.5 cm) and C (4.6+/-0.7 cm) than in group B (3.5+/-0.4 cm) (p<0.05). The temperature at the mid-point between the two probes was higher in group A than other groups: 99 degrees C in group A, 88.9 degrees C in group B, and 94.3 degrees C in group C (p>0.05). The ratios of the diameter of the long-axis to the diameter of the vertical-axis of groups A, B and C were 1.1+/-0.1, 1.2+/-0.1, and 1.1+/-0.2, respectively (p<0.05). Bipolar RFA using intraelectrode cooling and the interstitial saline perfusion simultaneously produced ablation zones significantly larger than the area produced by only one measure.

Animals↗
PubMed2003

Liposome-complexed adenoviral gene transfer in cancer cells expressing various levels of coxsackievirus and adenovirus receptor.

PURPOSE: Loss of coxsackievirus and adenovirus receptor (CAR) is frequently observed in malignant cancer, hampering adenoviral gene therapy approaches. Complexing adenovirus with cationic liposomes can increase adenoviral transgene expression, particularly in cells with CAR-deficiency. We investigated whether other factors such as lipid composition might be involved in determining the efficiency of liposome-complexed adenoviral gene transfer in cancer cells. MATERIAL AND METHODS: Human cancer cell lines with different expression levels of CAR were infected with a GFP transgene. The efficiency of transgene expression was assessed by determining GFP expression using FACS analysis. RESULTS: The efficiency of liposome-complexed adenoviral gene transfer was dependent on the lipid composition constituting liposomes. Polyethylene glycol (PEG)-containing liposomes were most effective in increasing liposome-complexed adenoviral gene transfer. In CAR-deficient cells, use of PEG-containing liposomes enhanced adenoviral gene transfer, whereas in CAR-expressing cells enhancement varied depending on cell type. In some CAR-expressing cells, the effect of liposome complexing was even comparable to that in CAR-deficient cells. Increased adenoviral transgene expression following complexing with PEG-containing liposomes correlated with liposome uptake in cancer cells. CONCLUSIONS: Liposome-complexed adenoviral gene transfer appears to depend on lipid composition and the level of liposome uptake by cancer cells, in addition to CAR levels. Our study suggest that these multiple factors should be considered in designing liposome-complexed adenoviral vectors to improve outcomes of current adenoviral cancer gene therapies.

Adenoviridae↗
PubMed2003

Dynamic and quantitative evaluation of eyelid motion using image analysis.

Evaluation of facial movement, especially eyelid movement, has depended on the subjective judgment of trained clinicians. Recently, a few objective methods have been reported, but they required uncomfortable markers to be attached to the eyelids and a special-purpose, high-speed video camera. This study had two aims: one was to develop a new device for measuring eyelid motion dynamically and quantitatively, without eyelid markers or a high-speed camera; the other was to devise feasible parameters for eyelid motion. The system consisted of a personal computer with a general-purpose multimedia board and a software program that the authors named blepharokymography. A sequence of blinking eyes was recorded with a video camera. After the capturing process of the video, kymograms were produced from the movie file. Kymograms were converted to binary images by threshold filtering. The lower margin of the upper eyelid was traced, and displacement and velocity curves were obtained. Some parameters were devised and verified in preliminary clinical data. The analysis revealed that the displacement (8 mm in normal compared with 5.2 mm in paralysis), average closing velocity (74 mm s(-1) in normal compared with 30.6 mm s(-1) in paralysis) and peak closing velocity (154 mm s(-1) in normal against 63.4 mm s(-1) in paralysis) were useful parameters for differentiating the normal and facial-paralysis states.

Adolescent↗
PubMed2003

Characterization of the 3'-terminal nucleotide sequence of two Korean isolates of Daphne virus S support its placement as a distinct species of the genus Carlavirus.

This study determined the 3'-terminal nucleotide sequences of two Korean isolates of Daphne virus S (DVS), a tentative member of the genus Carlavirus, causing leaf distortion and chlorotic spot disease symptoms in daphne plants. The 3'-terminal 1,465 nucleotide sequences of the two isolates contained two open reading frames coding for proteins of 36 kDa viral coat protein (CP) and 12 kDa from the 5'-3' end, which is a typical genome structure of the 3'-terminal region of carlaviruses. Both DVS isolates were 98.1% and 93.6% amino acid identical in the CP and 12 kDa, respectively. The CP gene of DVS shares 25.2-55.2% and 42.9-56.1% similarities with that of 19 other carlaviruses at the amino acid and nucleotide levels, respectively. The 3'-proximal 12 kDa gene of DVS shares 20.2-57.8% amino acid identities with that of 18 other members of the genus. The 3' noncoding region of DVS consists of 73 nucleotides with long excluding poly A tract, and shares 69.1-77.1% identities to the known carlaviruses. In the phylogenetic analyses of the two proteins, DVS was closely related to Helenium virus S and Chrysanthemum virus B. This is the first sequence information for the DVS, and further confirms the classification of DVS as a distinct member of the genus Carlavirus.

3' Untranslated Regions↗