Biomedical subjects

Sung Ki Cho

Publications and source records attributed to Sung Ki Cho.

16 recordsLinked to original sources

PubMed2006

Diaphragmatic weakness after transcatheter arterial chemoembolization of inferior phrenic artery for treatment of hepatocellular carcinoma.

PURPOSE: To prospectively assess the diaphragmatic anatomic and functional consequences of transcatheter arterial chemoembolization (TACE) of the inferior phrenic artery in patients with hepatocellular carcinoma. MATERIALS AND METHODS: Informed consent and institutional review board approval were obtained. Fifteen patients (13 men, two women; mean age, 52 years; age range, 22-61 years) who underwent TACE of the inferior phrenic artery for treatment of hepatocellular carcinoma were enrolled. The right inferior phrenic artery was embolized in 14 patients, and the left inferior phrenic artery was embolized in one patient. Chest radiography, fluoroscopy, computed tomography (CT), and pulmonary function tests were performed before and after TACE of the inferior phrenic artery. The post-TACE examinations were performed 2-3 months after TACE, and the results were compared with those of the pre-TACE examinations. A paired t test or the Wilcoxon signed rank test was used for statistical analyses. RESULTS: At chest radiography and fluoroscopy, six of 15 patients (40%) had both elevation and movement abnormality of the ipsilateral hemidiaphragm after TACE of the inferior phrenic artery. The mean (+/- standard deviation) diaphragmatic thickness on CT scans changed from 9.11 mm +/- 3.02 to 7.67 mm +/- 2.27 after TACE (P = .048). The mean vital capacity also was significantly decreased after TACE, from 91.87% +/- 18.52 to 82.27% +/- 16.94 of the predicted value (P = .006). The decreases in diaphragmatic thickness and vital capacity were most pronounced in the patients with abnormal findings at chest radiography and fluoroscopy. CONCLUSION: After TACE of the inferior phrenic artery, a substantial portion of patients showed functional and anatomic evidence of diaphragmatic weakness.

Adult↗

PubMed2006

A petal breakstrength meter for Arabidopsis abscission studies.

BACKGROUND: Abscission is the regulated dropping of plant organs, such as leaves or flower petals. This process involves a break down of the cell wall between layers of cells in the abscission zone, causing the organ to become detached. The model plant Arabidopsis thaliana undergoes floral organ abscission. Various experimental methods have been used to study Arabidopsis floral organ abscission, including measuring the petal breakstrength, or the amount of force required to pull a petal from the receptacle. Petal breakstrength provides a quantitative insight into the physical integrity of the petal abscission zone. RESULTS: We developed a petal breakstrength meter that allows rapid data acquisition on a personal computer. We present the design of the device and show its utility in measuring Arabidopsis petal breakstrength for abscission studies. CONCLUSION: This petal breakstrength meter should enable researchers to perform the petal breakstrength assay as a routine part of the characterization of environmental and genetic factors affecting abscission.

Journal Article↗

PubMed2006

Use of the right external jugular vein as the preferred access site when the right internal jugular vein is not usable.

PURPOSE: The present study describes the authors' experience with central venous access through the right external jugular vein (EJV) when the right internal jugular vein (IJV) is not available. MATERIALS AND METHODS: A retrospective study of 23 patients in whom a central venous catheter placement was attempted via the right EJV was conducted. The reasons for catheterization via the right EJV included clinically silent occlusion of the right IJV (n = 17), localized skin infection overlying the right IJV related to a previous catheterization (n = 3), presence of an existing Hickman catheter in the right IJV (n = 1), and concern regarding the risk of catheter-related infection secondary to right IJV catheterization in patients with a tracheostomy tube device adjacent to the presumed site of right IJV catheterization (n = 2). Technical success, procedural complications, and follow-up results including catheter dwell time and delayed or late complications (eg, symptomatic venous thrombosis, catheter-related infection, and catheter malfunction) were assessed. Adverse events were expressed as events per 100 catheter-days of use. RESULTS: Technical success was achieved in 22 of 23 patients (96%). There were no procedural complications. The catheter dwell time ranged from 2 to 182 days, with a mean dwell time of 62.7 days. There were four delayed or late complications (three catheter-related infections, 0.22 per 100 catheter-days; one catheter malfunction, 0.07 per 100 catheter-days). No cases of symptomatic venous thrombosis were noted. CONCLUSION: The right EJV is an acceptable and preferred access site when the right IJV is not available for central venous catheterization.

Adult↗

PubMed2006

Arteriovenous malformations of the body and extremities: analysis of therapeutic outcomes and approaches according to a modified angiographic classification.

PURPOSE: To propose a modified angiographic classification for peripheral arteriovenous malformations (AVMs) and to determine its value for assessing therapeutic outcomes and approaches to ethanol embolization of AVMs in the body and extremities. METHODS: AVMs of the trunk and extremities were categorized according to the angiographic morphology of the nidus: type I (arteriovenous fistulae), type II (arteriolovenous fistulae), type IIIa (arteriolovenulous fistulae with non-dilated fistula), and type IIIb (arteriolovenulous fistulae with dilated fistula). Sixty-six patients (41 women; mean age 28.3 years, range 5-53) with inoperable AVMs in the body and extremities who underwent staged ethanol embolizations were retrospectively analyzed. Therapeutic outcomes and approaches were evaluated according the above classification system. RESULTS: The 66 AVMs were composed of 30 (45%) type IIIb, 13 (20%) type II, 12 (18%) mixed types IIIa and IIIb, 9 (14%) mixed types II and IIIb, and 2 (3%) type IIIa. Ethanol embolization was most effective for type II (100%), and more effective for type IIIb (83%) than for type IIIa or mixed types (< or = 50%). Despite the use of the transarterial approach, direct puncture and transvenous approaches were more relevant for treating type II AVMs. Only the transarterial approach was used for treating type IIIa; both direct puncture and transarterial approaches were used for treating the other types. CONCLUSION: The described angiographic classification provides considerable information concerning the characteristics of AVMs in the body and extremities, the optimal therapeutic approach, and the likely therapeutic outcome.

Adolescent↗

PubMed2005

Analysis of differentially expressed transcripts of fungal elicitor- and wound-treated wild rice (Oryza grandiglumis).

Suppression subtractive hybridization was used to construct a subtracted library (ogfw) from plants of a wild rice species, Oryza grandiglumis, subjected to a fungal elicitor and physical wounding. To screen the differentially expressed transcripts in the library, we applied a reverse Northern blot analysis to a cDNA microarray containing 1,152 random clones. Based on the average expression ratio, we selected 156 clones showing an elevated expression level. The elevated expression levels and overall expression profiles over time were verified by Northern blot analysis. A comparative functional categorization of the subtracted expressed sequence tags (ESTs) of the ogfw library against ESTs isolated from blast-infected O. sativa showed that the functional categories of cell rescue, defense and virulence, transcription, and cellular transport and transport mechanism of the ogfw library were threefold higher in the former than in the latter. These subtracted ESTs can be presumed to be related to the defense/resistance system and will be used to investigate the defense mechanisms of wild rice and to provide new insights into the genome of wild rice, which in turn will assist molecular breeding strategies of cultivated rice.

Amino Acid Sequence↗

PubMed2005

A partial-complementary adapter for an improved and simplified ligation-mediated suppression PCR technique.

Ligation-mediated suppression PCR (LMS-PCR) is a powerful tool for walking in unknown genomic DNA regions from known adjacent sequences. This approach has made it feasible to obtain promoter sequences and to enable researchers to identify full-length gene sequences or isoforms of multigene families. However, the advantages of LMS-PCR can be obviated by the presence of incomplete base modifications on the suppression adapters. We propose here that a 'partial-complementary adapter' is a more reliable suppression adapter, demanding only 5'-end phosphorylation. We also describe a simplified procedure for the easier preparation of PCR templates with very small quantities of DNA and a fast and direct characterization of the suppression-PCR products. A set of practical guidelines is proposed for pre-checking the efficiency of the adapter modification using two model systems: bacteriophage lambda (lambda) and Arabidopsis.

Arabidopsis↗

PubMed2005

Characterization of Ty3-gypsy-like elements in Hibiscus syriacus.

Southern blot analysis revealed a ubiquitous distribu-tion and high copy number of Ty3-gypsy-like elements in the genome of Hibiscus syriacus. Comparative phylogenetic analysis of the large subunit of Rubisco and the integrase region of Ty3-gypsy elements in various plant species indicated that the retrotransposon-like sequences have different evolutionary histories and their own unique polymorphism in the H. syriacus population. Sequence-tagged site-restriction fragment length polymorphisms (STS-RFLP) analysis also indicated great variability in the numbers and sequences of Ty3-gypsy-like elements within H. syriacus varieties. Ty3-gypsy-like elements may still be active within H. syriacus, since Northern analysis of wounded leaves of H. syriacus variety Saehan with a probe for the integrase domain gave strong hybridization signals. The sequence heterogeneity and ubiquity of the Ty3-gypsy-like elements in H. syriacus genomes could provide reliable DNA markers for line identification as well for the analysis of genetic diversity in H. syriacus.

Amino Acid Sequence↗

PubMed2004

Identification of genes induced in wound-treated wild rice (Oryza minuta).

A subtracted library was constructed from wound-treated wild rice (Oryza minuta) by suppression subtractive hybridization (SSH) in combination with mirror orientation selection (MOS). To distinguish between differentially expressed transcripts and false positive clones, DNA chips containing 960 random clones were applied as a form of reverse Northern screening. Based on the signal intensities and expression ratios obtained from experiments performed in triplicate, 371 clones were selected. ESTs produced from the subtracted library showed 63.2% redundancy, and 72% of all clones could be matched to the GenBank nonredundant database. Functional categorization placed the identified enriched genes in categories of subcellular localization, metabolism, cell rescue and defense, and transcription. These EST-related resistance mechanisms could be used in investigations into the defense mechanisms of wild species, and to provide new routes to improving the germplasm of cultivated rice.

Databases, Nucleic Acid↗

PubMed2002

Diversity and varietal classification of Hibiscus syriacus L. with the heterogeneity within retrotransposon-like elements.

Retrotransposons are present in multi-copy numbers that are integrated into plant genomes with considerable heterogeneous sequences within a single plant and between plant species, which allows the use of retrotransposons as additional sources of DNA polymorphism. A primer design for the sequence-tagged specific site and cleaved amplified polymorphic sequences (STS-CAPs) that are derived from retrotransposon-like sequences was developed for the molecular marker analysis in Hibiscus syriacus. This method was applied for the detection of sequence variations of intact retrotransposons that exist in plant genomes, which resulted in higher polymorphisms than in the amplified fragment length polymorphism (AFLP). Through STS-CAPs, specific fingerprinting data among H. syriacus varieties can be easily distinguished and generated with reproducible results. It could also be adapted to any species that possess multi-copy retrotransposons for varietal identification as well as the assessment of genetic relationships.

DNA Fingerprinting↗

PubMed2002

Construction of two pGEM-7Zf(+) phagemid T-tail vectors using AhdI-restriction endonuclease sites for direct cloning of PCR products.

For applications such as sequencing, transfection, and in vitro transcription, PCR products have to be subcloned into plasmids. Many strategies are used for cloning, blunt-end ligation or the incorporation of restriction endonuclease sites into PCR primers for appropriate vectors. However, the most convenient and direct method is T/A cloning. In this study, we developed two of the pGEM-7Zf(+) phagemid T-tail vectors using AhdI-restriction endonuclease sites, and these T vectors have all the features of pGEM-7Zf(+): f1 ori, T7, and SP6 RNA polymerase promoters, the alpha-peptide coding region of beta-galactosidase for X-gal blue/white color selection, the beta-lactamase gene for recombinant colony selection, and binding sites for pUC/M13 forward and reverse sequencing primers. These AhdI-containing phagemid vectors, pGEM-NJ105 and pGEM-NJ107, are useful for the easy and inexpensive preparation of T vectors and direct cloning of PCR products.

Base Sequence↗

PubMedDate not supplied

Iatrogenic aorto-cisterna chyli fistula during percutaneous balloon aortoplasty in a patient with Takayasu's arteritis: a case report.

We present a case of iatrogenic aorto-cisterna chyli fistula that developed during percutaneous transluminal aortoplasty in a 16-year old girl with Takayasu's arteritis. The aorto-cisterna chyli fistula was angiographically confirmed and treated using a stent-graft, which successfully occluded the fistula. Her claudication then improved, although follow-up CT angiography at 10 months revealed mild recurrent aortic stenosis.

Adolescent↗

PubMedDate not supplied

Perfusion MR imaging: clinical utility for the differential diagnosis of various brain tumors.

OBJECTIVE: To determine the utility of perfusion MR imaging in the differential diagnosis of brain tumors. MATERIALS AND METHODS: Fifty-seven patients with pathologically proven brain tumors (21 high-grade gliomas, 8 low-grade gliomas, 8 lymphomas, 6 hemangioblastomas, 7 metastases, and 7 various other tumors) were included in this study. Relative cerebral blood volume (rCBV) and time-to-peak (TTP) ratios were quantitatively analyzed and the rCBV grade of each tumor was also visually assessed on an rCBV map. RESULTS: The highest rCBV ratios were seen in hemangioblastomas, followed by high-grade gliomas, metastases, low-grade gliomas, and lymphomas. There was no significant difference in TTP ratios between each tumor group (p<0.05). At visual assessment, rCBV was high in 17 (81%) of 21 high-grade gliomas and in 4 (50%) of 8 low-grade gliomas. Hemangioblastomas showed the highest rCBV and lymphomas the lowest. CONCLUSION: Perfusion MR imaging may be helpful in the differentiation of thevarious solid tumors found in the brain, and in assessing the grade of the various glial tumors occurring there.

Adolescent↗

PubMedDate not supplied

Stent placement for chronic iliac arterial occlusive disease: the results of 10 years experience in a single institution.

OBJECTIVE: We wanted to retrospectively evaluate the long-term therapeutic results of iliac arterial stent placement that was done in a single institution for 10 years. MATERIALS AND METHODS: From May 1994 to April 2004, 206 patients who underwent iliac arterial stent placement (mean age; 64+/-8.8) were followed up for evaluating the long term stent patency. Combined or subsequent bypass surgery was performed in 72 patients. The follow up period ranged from one month to 120 months (mean; 31+/-25.2 months). The factors that were analyzed for their effect on the patency of stents were age, the stent type and diameter, the lesion site, lesion shape, lesion length, the Society of Cardiovascular and Interventional Radiology criteria, the total run off scores, the Fontaine stage and the cardiovascular risk factors (diabetes mellitus, hypertension and smoking). Follow-up included angiography and/or CT angiography, color Doppler sonography and clinical evaluation with the ankle-brachial index. RESULTS: Two hundred and eighty-four stents were placed in 249 limbs of 203 patients. The technical success rate was 98% (203/206). The primary patency rates of the stents at 3, 5, 7 and 10 year were 87%, 83%, 61% and 49%, respectively. One hundred seventy-seven patients maintained the primary stent patency until the final follow up and 26 patients showed stenosis or obstruction during the follow up. Secondary intervention was performed in thirteen patients. Lesions in the external iliac artery (EIA) or lesions in both the common iliac artery (CIA) and EIA were a poor prognostic factor for stent patency. The run off score and stent diameter also showed statistically significant influence on stent patency. The overall complication rate was 6%. CONCLUSION: Iliac arterial stent placement is a safe treatment with favorable long term patency. Lesions in the EIA or lesions in both the EIA and CIA, poor run off vessels and a stent having the same or a larger diameter than 10 mm were the poor prognostic factors for long term stent patency.

Aged↗

PubMedDate not supplied

Efficacy of femoral vascular closure devices in patients treated with anticoagulant, abciximab or thrombolytics during percutaneous endovascular procedures.

OBJECTIVE: This study assessed the outcomes of using vascular closure devices following percutaneous transfemoral endovascular procedures in the patients who were treated with heparin, abciximab or thrombolytics (urokinase or t-PA) during the procedures. MATERIALS AND METHODS: From March 28, 2003 to August 31, 2004, we conducted a prospective and randomized study in which 1,676 cases of 1,180 patients were treated with one of the two different closure devices (the collagen plug device was Angio-Seal; the suture-mediated closure device was The Closer S) at the femoral access site after instituting percutaneous endovascular procedures. Among the 1,676 cases, 108 cases (the drug group) were treated with heparin only (n = 94), thrombolytics only (n = 10), heparin and thrombolytics (n = 3), or abciximab and thrombolytics (n = 1) during the procedures; 1,568 cases (the no-drug group) were treated without any medication. We compared the efficacy and complications between the two groups. Of the drug group, 42 cases underwent arterial closures with the collagen plug devices and 66 cases underwent arterial closures with the suture-mediated closure devices. We also compared the efficacy and complications between these two groups. RESULTS: The immediate hemostasis rates were 92.9% (1,456/1,568) in the no-drug group and 91.7% (99/108) in the drug group. Early complications occurred in four cases of the drug group. These included two episodes of rebleeding with using the Closer S, which required manual compression for at least 10 minutes, and two episodes of minor oozing with using one Angio-Seal and one Closer S, which required two hours of additional bed rest. There was no late complication. So, the total success rates were 90.8% (1,423/1,568) in the no-drug group and 88.0% (95/108) in the drug group. These results were not significantly different between the two groups (p = 0.34). In the drug group, the difference of the successful hemostasis rate between the collagen plug devices and the suture-mediated devices was also not statistically significant (92.9% vs. 84.8%, respectively; p = 0.21). CONCLUSION: Arterial closure of the femoral access site with using vascular closure devices is both safe and effective, even in the patients who received heparin, abciximab or thrombolytics.

Abciximab↗

PubMedDate not supplied

Subintimal angioplasty in the treatment of chronic lower limb ischemia.

OBJECTIVE: To present our experience with subintimal angioplasty (SA) for treatment of chronic lower limb ischemia (CLLI) and to assess its effectiveness and durability. MATERIALS AND METHODS: From April 2003 through June 2005, we treated 40 limbs in 36 patients with CLLI by SA. Balloons with or without secondary stent placement appropriate in size to the occluded arteries were used for SA of all lesions, except for iliac lesions where primary stent placement was done. The patients were followed for 1-23 months by clinical examination and color Doppler ultrasound and/or CT angiography. Technical results and outcomes were retrospectively evaluated. The presence of a steep learning curve for performance of SA was also evaluated. Primary and secondary patencies were determined using Kaplan-Meier analysis. RESULTS: Technical success was achieved in 32 (80%) of 40 limbs. There was no statistical difference between technical success rates of 75% (18/24) during the first year and 88% (14/16) thereafter. There were four complications (10%) in 40 procedures; two arterial perforations, one pseudoaneurysm at the puncture site, and one delayed hematoma at the SA site. Excluding initial technical failures, the primary patency rates at six and 12 months were 68% and 55%, respectively. Secondary patency rates at six and 12 months were 73% and 59%, respectively. CONCLUSION: Subintimal angioplasty can be accomplished with a high technical success rate. It should be attempted in patients with CLLI as an alternative to more extended surgery, or when surgical treatment is not recommended due to comorbidity or an unfavorable disease pattern.

Aged↗

PubMedDate not supplied

Percutaneous treatment of failed native dialysis fistulas: use of pulse-spray pharmacomechanical thrombolysis as the primary mode of therapy.

OBJECTIVE: To determine the efficacy and outcome of percutaneous treatment in restoring the function of failed native arteriovenous fistulas (AVFs) where pulse-spray pharmacomechanical thrombolysis was used as the primary mode of therapy. MATERIALS AND METHODS: From June 2001 to July 2005, 14 patients who had thrombosis of native AVFs underwent percutaneous restoration following 20 episodes of thrombosis. These included 6 repeated episodes in one forearm AVF and two episodes in another forearm AVF. All patients except one were treated with urokinase injection utilizing the pulse-spray technique and had subsequent balloon angioplasty. One patient was treated by percutaneous angioplasty alone. We retrospectively evaluated the feasibility of percutaneous treatment in restoring the function of the failed AVFs. The primary and secondary patencies were calculated by using a Kaplan-Meier analysis. RESULTS: Both technical and clinical success were achieved in 15 (75%) of 20 AVFs. Four of the five technical failures resulted from a failure to cross the occluded segment. One patient refused further participation in the trial through a brachial artery access following failure to cross the occluded segment via an initial retrograde venous puncture. There were no major procedure related complications observed. Including the initial technical failures, primary patency rates at six and 12 months were 64% and 55%, respectively. Secondary patency rates at six and 12 months were 71% and 63%, respectively. CONCLUSION: Pulse-spray pharmacomechanical thrombolysis for treatment of the thrombosed AVFs is safe, effective and durable. This procedure should be considered as an option for the management of failed AVFs prior to surgical intervention.

Adult↗