Biomedical subjects

S W Lee

Publications and source records attributed to S W Lee.

At least 37 records · Page 2Linked to original sources

PubMed2005

Epigastric pain in a patient with neurofibromatosis type 1.

Patients with neurofibromatosis type 1 are at increased risk of developing carcinoid tumours of the duodenum, particularly in the ampulla of Vater. Aggressive surgery with pancreatoduodenectomy is recommended for all ampullary carcinoid tumours because of their propensity to metastasise. We report a case of a 43-year-old woman with neurofibromatosis type 1, who presented with recurrent epigastric pain for 15 months. Evaluation using magnetic resonance cholangiopancreatography and side-viewing duodenoscopy revealed a submucosal tumour at the ampulla of Vater causing pancreatobiliary ductal obstruction and dilation. The ampullary tumour was overlooked initially by forward-viewing endoscopy. The patient subsequently underwent pancreatoduodenectomy. Histological examination of the surgically resected specimen confirmed the presence of a carcinoid tumour, with metastasis to peri-pancreatic lymph nodes. She remained asymptomatic 10 months after surgery.

Abdominal Pain↗

PubMed2004

Laparoscopic total colectomy: hand-assisted vs standard technique.

BACKGROUND: Although hand-assisted laparoscopic surgery (HALS) has been proposed as an alternative to laparoscopically assisted surgery (LAP), little is known about its role in total colectomy. The objectives of the study were to compare the outcomes in patients undergoing total colectomy via either HALS or LAP and to determine what benefits HALS might have in extensive colorectal procedures. METHODS: We reviewed the data for 23 patients who underwent total proctocolectomy (TPC) or total abdominal colectomy (TAC) using either a HALS or LAP technique. RESULTS: There were 12 HALS (five TPC, seven TAC) and 11 LAP (seven TPC, four TAC) for ulcerative colitis (n = 17), familial polyposis (n = 5), and colonic inertia (n = 1). One LAP was converted (9.1%). The operative time was shorter for HALS than for LAP (210 vs 273 min; p = 0.03). Blood loss and incision length were similar. Postoperative recovery and morbidity rates were comparable. CONCLUSION: HALS reduces the operative time but patient morbidity rates and recovery are similar to LAP. HALS may be preferable for extensive colorectal procedures such as TPC and TAC.

Adolescent↗

PubMed2004

Laparoscopic approach for early gastric cancer within a paraesophageal hiatal hernia.

We present a case of early gastric cancer located in gastric volvulus associated with paraesophageal hiatal hernia. Two lesions of EGC were diagnosed in the distal third of the stomach, most of which had herniated into the left chest through a large hiatal defect in an organoaxial fashion. Routinely, laparoscopic-assisted distal gastrectomy (LADG) is our preferred approach for EGC, and the presence of hiatal hernia in this case did not alter our approach. Laparoscopic repair of hiatal hernia was performed successfully followed by LADG. A review of the literature supports a minimally invasive approach for both procedures and shows it to be safe, effective, and technically feasible. Further, LADG is shown to be oncologically adequate in terms of tumor margins and lymph node dissection, but its relevance to long-term disease-free survival still needs to be studied in well-designed prospective trials.

Gastrectomy↗

PubMed2004

Production of fructo-oligosaccharides from molasses by Aureobasidium pullulans cells.

Three different strains of Aureobasidium pullulans were grown in batch cultures to compare their abilities for the production of fructo-oligosaccharides. Specific intracellular enzyme activity was the highest with strain KCCM 12017 and enzyme production was closely coupled to growth. Using A. pullulans cells, 166 g/l fructo-oligosaccharides was produced from 360 g/l molasses sugar as sucrose equivalent at 55 degrees C and pH 5.5 after 24 h incubation.

Agriculture↗

PubMed2004

A seroprevalence study of poliovirus antibody among primary schoolchildren in Korea.

We aimed to determine the seroprevalence of poliovirus antibody in Korea by using the cell culture neutralization method recommended by the WHO. A total of 500 sera collected from children at eight primary schools in Kyunggi province were used for this study. We found that 82.2% of children were positive for all three types of poliovirus and antibody-positive rates for types I, II and III were 94.4, 96.6 and 86.8% respectively, indicating that seropositive rates for types I and II were considerably higher than for type III (P<0.0001). This result implies that the type III component of the oral polio vaccine should be evaluated further. Although a greater number of children, including young infants, need to be tested for seroprevalence, this study still provides us with valuable information on the effectiveness of vaccination against polioviruses in Korea.

Antibodies, Viral↗

PubMed2004

Novel method for cell immobilization and its application for production of oligosaccharides from sucrose.

AIMS: The purpose of the present investigation was to develop a novel method for cell immobilization. METHODS AND RESULTS: Aureobasidium pullulans cells were mixed with an alginate solution, and the mixture was extruded to form small gel beads as hydrated-immobilized cells. The beads were then placed at -15 degrees C for 6-24 h to induce freeze-dehydration. The freeze-dehydration resulted in shrinkage of beads as a result of water removal reducing bead volume by 82% and bead weight by 85%. The dehydrated beads were successfully used for the production of fructo-oligosaccharides in a model reactor system. CONCLUSIONS: Dehydrated beads may provide some commercial advantages over conventional immobilized cells. SIGNIFICANCE AND IMPACT OF THE STUDY: This study shows that bioreactor performance can be improved up to two times by the use of the dehydrated beads.

Alginates↗

PubMed2004

The dual-wave bolus feature in continuous subcutaneous insulin infusion pumps controls prolonged post-prandial hyperglycaemia better than standard bolus in Type 1 diabetes.

The dual-wave bolus delivers a combination of an immediate normal pre-meal insulin bolus (approximately 3 min) followed by an extended (or square-wave) bolus that is evenly delivered over several hr as programmed by the patient. The purpose of this study was to compare post-prandial glycaemic excursions following a high-fat meal after administration of insulin by normal vs dual-wave bolus. During this prospective, cross-over, repeated measures study, subjects with diabetes and treated with insulin pump therapy were evaluated using the continuous glucose monitoring system (CGMS) following three combinations of meal and bolus type. A control meal or a high-fat meal was given in place of the evening meal on three separate occasions and comparisons were made between: a) the control meal with normal insulin bolus delivery, b) the high-fat meal with normal insulin bolus delivery, and c) the high-fat meal with dual-wave insulin bolus delivery. Although mean baseline CGMS values were similar in each of the three combinations of meal and bolus type (p=0.54) and in the three hr immediately following the meal (p=0.64, p=0.83, p=1.0), when compared to the control meal/normal bolus and high-fat meal/dual-wave bolus combinations, CGMS profiles disclosed significantly elevated post-prandial glucose in hr 5 through 14 (p<0.05) following the high-fat/normal bolus combination. Prolonged post-prandial glycaemic excursions are identified using the CGMS. Treating post-prandial hyperglycaemia with dual-wave insulin delivery may help manage chronic hyperglycaemia in patients with diabetes.

Area Under Curve↗

PubMed2003

Multidetector row computed tomography for follow-up of patients with coronary artery aneurysms due to Kawasaki disease.

Multidetector row computed tomography (MDCT) coronary angiography was performed using a 16-slice MDCT scanner in three children with coronary aneurysms due to Kawasaki disease. Patients were given a beta-blocker. Following contrast injection, all data were acquired during a 20-second breathhold. Results were compared with those of conventional coronary angiography performed previously. MDCT provided clear visualization of coronary artery aneurysms, with coronary calcifications but which had not yet progressed to stenotic lesions. Because MDCT allows noninvasive detection and exclusion of coronary obstructions, it may be able to replace repeat conventional angiography as a follow-up study for children with coronary artery disease.

Child↗

PubMed2003

Peritoneal macrophage and blood monocyte functions after open and laparoscopic-assisted cecectomy in rats.

BACKGROUND: It has been well established that open abdominal surgery results in systemic immunosuppression postoperatively; in contrast, laparoscopic surgery is associated with significantly better preserved systemic immune function. However, when intraperitoneal (local) immune function is considered, laparoscopic procedures done under a CO2 pneumoperitoneum (pneumo) have been shown to result in greater immunosuppression compared to that of open surgery. Few studies have simultaneously assessed systemic and local immune function. The purpose of this study was to assess peripheral blood mononuclear cell (PBMC) and peritoneal macrophage tumor necrosis factor-alpha (TNF-alpha) levels, H2O2 production, and MHC class II antigen expression after open and laparoscopically assisted cecectomy in a rat model. METHODS: A total of 75 Sprague Dawley rats were used for three separate experiments. For each study, rats were randomly divided into three groups: anesthesia alone (AC), laparoscopic-assisted cecectomy (LC), and open cecectomy via full laparotomy (OP). A CO2 pneumo was used for laparoscopic operations. On postoperative day 1 the animals were sacrificed, macrophages were harvested via intraperitoneal lavage, and PBMCs were isolated from whole blood obtained by cardiac puncture. In experiment 1, macrophages and PBMC from each animal were stimulated with lipopolysaccharide, after which TNF-alpha levels of the supernatant were determined. In experiment 2, after stimulation with PMA, H2O2 release was assessed by measuring fluorescence. In experiment 3, via flow cytometry, the number of cells with surface MHC class II proteins were determined. Data from the three groups in each experiment were compared using analysis of variance Tukey-Kramer tests. RESULTS: Macrophages and PBMC from rats in the OP group released significantly more TNF-alpha than cells from rats in the LC ( p < 0.05) or AC ( p < 0.05) groups. Macrophages from rats in the OP group released significantly less H2O2 than cells from the AC ( p < 0.01) and LC ( p < 0.05) groups. There was no difference between the AC and LC results. No significant differences in PBMC H2O2 release were noted among any of the groups. OP group macrophages expressed significantly less MHC class II antigen than did AC group macrophages ( p < 0.05). No differences were noted among the LC results and either the OP or AC group's outcomes. No differences were noted in PBMC MHC class II expression among any of the groups. CONCLUSIONS: In all instances, the LC group's macrophage results were similar to the AC group's results. OC group macrophages produced significantly more TNF-alpha and less H2O2 than both the AC and LC groups. MHC class II protein expression was less for the OC group than for the AC group. OC group PBMCs produced more TNF-alpha. No differences in PBMC H2O2 release or MHC class II expression were noted. Laparoscopic methods better preserves the baseline values of the parameters studied.

Animals↗

PubMed2003

Hand-assisted laparoscopic colorectal surgery using GelPort.

BACKGROUND: An easily usable hand access device will optimize success in hand-assisted laparoscopic surgery (HALS). The authors describe their initial series of HALS colorectal resections using GelPort to evaluate their current technique and results with this new device. METHODS: A retrospective study investigated 33 HALS colorectal procedures including total colectomy ( n = 16) and low anterior resection ( n = 10). All operative data, including intraoperative GelPort performance, were prospectively recorded and retrospectively analyzed. RESULTS: In this study, 3 (9.1%) of 33 HALS procedures were converted to open surgery, and 4 (13.3%) of 30 HALS procedures required minimal enlargement of incisions to facilitate extracorporeal procedures. The operative time was 263 +/- 85 min, and the blood loss was 282 +/- 148 ml. There were no device malfunctions. Three major complications (9.1%) and 7 minor wound infections (21%) were noted postoperatively. The mean hospital stay was 7.9 +/- 3.8 days. CONCLUSION: When performed with GelPort, HALS is safely and reliably applicable for various colorectal procedures.

Adult↗

PubMed2003

Aminoacyl-tRNA synthetases and their inhibitors as a novel family of antibiotics.

The emergence of multidrug-resistant strains of pathogenic microorganisms and the slow progress in new antibiotic development has led in recent years to a resurgence of infectious diseases that threaten the well-being of humans. The result of many microorganisms becoming immune to major antibiotics means that fighting off infection by these pathogens is more difficult. The best strategy to get around drug resistance is to discover new drug targets, taking advantage of the abundant information that was recently obtained from genomic and proteomic research, and explore them for drug development. In this regard, aminoacyl-tRNA synthetases (ARSs) provide a promising platform to develop novel antibiotics that show no cross-resistance to other classical antibiotics. During the last few years there has been a comprehensive attempt to find the compounds that can specifically target ARSs and inhibit bacterial growth. In this review, the current status in the development of ARS inhibitors will be briefly summarized, based on their chemical structures and working mechanisms.

Amino Acyl-tRNA Synthetases↗

PubMed2003

Participation of protein kinase C beta in osteoclast differentiation and function.

Protein kinase C (PKC) proteins have been shown to be involved in diverse cellular responses of various cell types. In experiments to identify genes regulated during osteoclast differentiation by a cDNA microarray approach, we found that the gene expression of PKC-betaII was upregulated in differentiated cells. Reverse transcription-polymerase chain reaction and Western blotting analyses also showed an increase in PKC-betaI as well as PKC-betaII during osteoclast formation in mouse bone marrow cell cultures in the presence of macrophage-colony stimulating factor (M-CSF) and receptor activator of nuclear factor-kappaB ligand (RANKL). Use of an antisense oligonucleotide to PKC-betaII resulted in a reduction in the RANKL-driven osteoclastogenesis. Pharmacological intervention with PKC-beta activity by the specific inhibitor CG53353 suppressed cellular differentiation and fusion processes during osteoclastogenesis and inhibited bone-resorbing function of mature osteoclasts. PKC-beta inhibition abolished the ERK and MEK activation by macrophage-colony stimulating factor and RANKL in osteoclast precursor cells whereas the cytokine-induced NF-kappaB activation was not hampered by the PKC-beta inhibition. Our findings indicate that PKC-beta has a role in regulation of osteoclast formation and function potentially by participating in the ERK signaling pathway of M-CSF and RANKL.

Animals↗

PubMed2003

A novel strategy for in vivo expansion of transplanted hepatocytes using preparative hepatic irradiation and FasL-induced hepatocellular apoptosis.

A strategy for inducing preferential proliferation of the engrafted hepatocytes over host liver cells should markedly increase the benefit of hepatocyte transplantation for the treatment of liver diseases and ex vivo gene therapy. We hypothesized that preparative hepatic irradiation (HIR) to inhibit host hepatocellular regeneration in combination with the mitotic stimulus of host hepatocellular apoptosis should permit repopulation of the liver by transplanted cells. To test this hypothesis, congeneic normal rat hepatocytes were transplanted into UDP-glucuronosyltransferase (UGT1A1)-deficient jaundiced Gunn rats (a model of Crigler-Najjar syndrome type I), following HIR and adenovirus-mediated FasL gene transfer. Progressive repopulation of the liver by engrafted UGT1A1-proficient hepatocytes over 5 months was demonstrated by the appearance of UGT1A1 protein and enzyme activity in the liver, biliary bilirubin glucuronides secretion, and long-term normalization of serum bilirubin levels. This is the first demonstration of massive hepatic repopulation by transplanted cells by HIR and FasL-induced controlled apoptosis of host liver cells.

Adenoviridae↗

PubMed2003

Molecular basis and characteristics of KATP channel in human corporal smooth muscle cells.

Relaxation of the corpus cavernosum smooth muscle is an absolute prerequisite for penile erection. Potassium channels play a role in the physiologic regulation of corporal smooth muscle tone. In spite of the physiological importance of K(ATP) channel in the modulation of corporal smooth muscle tone, there is a shortage of information available about the K(ATP) channel subtype(s) present in the corporal smooth muscle. The purpose of this study was to investigate the subunit type of K(ATP) channel, that is, the combinations of the Kir subunit and the SUR subunit in the human corporal smooth muscle and determine whether the electrophysiological kinetics and pharmacological properties of K(ATP) channels meet the subunit characteristics of the ion channel. We used cultured human corporal smooth muscle cells. To determine the presence of Kir and SURs subunits, RT-PCR was performed using Kir6.1, Kir6.2, SUR1, SUR2A, and SUR2B gene-specific primers. For electrophysiological recordings, the whole-cell, inside-out, and cell-attached configurations of the patch-clamp technique were used. We observed transcripts for Kir6.1, Kir6.2, and SUR2B in mRNA isolated from smooth muscle cells of cultured human corpus carvernosum. We recorded the unitary K(ATP) channel under the condition of intracellular and extracellular 140 mM [K(+)], and the slope conductance of the channel was 42.0+/-2.6 pS which is an intermediate conductance between that of either Kir6.1 or Kir6.2. The pinacidil (10 microM) increased the magnitude of the outward K(+) current (214.6+/-89.2%, n=12, < or = 0.05), which was blocked by the subsequent addition of the specific K(ATP) channel subtype selective blocker, glibenclamide (10 microM). The SIN-1(200 microM) induced increases in whole-cell outward K(+) currents (126.0+/-1.4%, n=4). The increased currents by SIN-1 were inhibited by glibenclamide (10 microM). We are the first to show that K(ATP) channel in human corporal smooth muscle is composed of Kir6.1-Kir6.2 construct expressed with SUR2B by RT-PCR. These findings, taken together with the electrophysiological results, suggest that K(ATP) channel in corporal smooth muscle cells is composed of heteromultimers of Kir6.1 and Kir6.2 with the ratio of 3 : 1 or 4 : 0 and SUR2B.

ATP-Binding Cassette Transporters↗

PubMed2003

Candidate defense genes from rice, barley, and maize and their association with qualitative and quantitative resistance in rice.

Candidate genes involved in both recognition (resistance gene analogs [RGAs]) and general plant defense (putative defense response [DR]) were used as molecular markers to test for association with resistance in rice to blast, bacterial blight (BB), sheath blight, and brown plant-hopper (BPH). The 118 marker loci were either polymerase chain reaction-based RGA markers or restriction fragment length polymorphism (RFLP) markers that included RGAs or putative DR genes from rice, barley, and maize. The markers were placed on an existing RFLP map generated from a mapping population of 116 doubled haploid (DH) lines derived from a cross between an improved indica rice cultivar, IR64, and a traditional japonica cultivar, Azucena. Most of the RGAs and DR genes detected a single locus with variable copy number and mapped on different chromosomes. Clusters of RGAs were observed, most notably on chromosome 11 where many known blast and BB resistance genes and quantitative trait loci (QTL) for blast, BB, sheath blight, and BPH were located. Major resistance genes and QTL for blast and BB resistance located on different chromosomes were associated with several candidate genes. Six putative QTL for BB were located on chromosomes 2, 3, 5, 7, and 8 and nine QTL for BPH resistance were located to chromosomes 3, 4, 6, 11, and 12. The alleles of QTL for BPH resistance were mostly from IR64 and each explained between 11.3 and 20.6% of the phenotypic variance. The alleles for BB resistance were only from the Azucena parent and each explained at least 8.4% of the variation. Several candidate RGA and DR gene markers were associated with QTL from the pathogens and pest. Several RGAs were mapped to BB QTL. Dihydrofolate reductase thymidylate synthase co-localized with two BPH QTL associated with plant response to feeding and also to blast QTL. Blast QTL also were associated with aldose reductase, oxalate oxidase, JAMyb (a jasmonic acid-induced Myb transcription factor), and peroxidase markers. The frame map provides reference points to select candidate genes for cosegregation analysis using other mapping populations, isogenic lines, and mutants.

Aldehyde Reductase↗

PubMed2003

Endothelial nitric oxide synthase gene polymorphisms in Behçet's disease and rheumatic diseases with vasculitis.

OBJECTIVE: To assess potential associations between Korean Behçet's disease (BD) or other rheumatic diseases with vasculitis and two polymorphisms of the endothelial nitric oxide synthase (eNOS) gene, which include the Glu298Asp polymorphism in exon 7 and a variable number of tandem repeats (VNTR) polymorphism in intron 4. METHODS: 65 patients with BD, 27 with rheumatic diseases with vasculitis, and 80 controls were studied. Analyses of the Glu298Asp polymorphism in exon 7 and VNTR polymorphism in intron 4 of the eNOS gene were made by the polymerase chain reaction (PCR)-restriction fragment length polymorphism technique and PCR genotyping, respectively. Additionally, HLA-B51 typing was performed in the BD group and controls by a two step PCR sequence-specific primers method. RESULTS: Significant differences in Glu298Asp genotype frequencies were found between the BD or vasculitis groups and the controls (BD group v controls: p(corr)=0.006; vasculitis group v controls: p<0.001). The Asp298 frequency was much higher in the BD and vasculitis groups than in the controls. Even after stratification of the BD group based on the results of HLA-B51 testing, a significant association of the Glu298Asp polymorphism was still found (p=0.002, Mantel-Haenszel weighted odds ratio 4.3, 95% confidence interval 1.7 to 10.9). Distribution of the genotype frequencies in two eNOS gene polymorphisms was similar in connective tissue diseases-associated vasculitis and primary vasculitic syndromes. In contrast, distribution of alleles and genotypes of VNTR polymorphism did not differ between BD or vasculitis groups and the controls. CONCLUSION: The Glu298Asp polymorphism in exon 7 of the eNOS gene seems to be a susceptibility gene for Korean BD and other rheumatic diseases.

Adult↗

PubMed2003

Effect of scheduled second therapeutic endoscopy on peptic ulcer rebleeding: a prospective randomised trial.

AIM: Recurrent bleeding after initial haemostasis is an important factor that directly relates to the outcome in the management of peptic ulcer bleeding. Conflicting reports have been published concerning the effectiveness of scheduled second therapeutic endoscopy on ulcer rebleeding. We investigate the use of scheduled second endoscopy with appropriate therapy on peptic ulcer rebleeding. METHODS: From August 1999 to January 2001, we prospectively randomised patients who had endoscopically confirmed bleeding peptic ulcer with stigmata of acute bleeding, visible vessel, or adherent clot into two groups. Endoscopic therapy was standardised to initial epinephrine injection and subsequent heater probe application. The study group (n = 100) received scheduled second endoscopy 16-24 hours after initial haemostasis, and further therapy was applied if endoscopic stigmata persisted, as above. The control group (n = 94) were observed closely. Those patients that developed rebleeding in either group underwent operation if further endoscopic therapy failed. Outcome measures included ulcer rebleeding, transfusion, duration of stay, and mortality. RESULTS: After initial endoscopic haemostasis, 194 eligible patients were randomised into two groups. Thirteen patients in the control group developed recurrent bleeding within 30 days while five patients in the study group sustained recurrent bleeding (p = 0.0314) (relative risks 0.33, 95% confidence interval 0.1-0.96). The number of patients that required surgery for recurrent bleeding was six in the control group and one in the study group (p = 0.05). There was no difference in duration of hospital stay, transfusion, or mortality between the two groups. CONCLUSIONS: A scheduled repeat endoscopy with appropriate therapy 16-24 hours after initial endoscopic haemostasis reduces the number of cases of recurrent bleeding.

Aged↗

PubMed2003

Reactivity of sera from cases of Plasmodium vivax malaria towards three recombinant antigens based on the surface proteins of the parasite.

Sera collected in South Korea, from 61 cases of Plasmodium vivax malaria and, as controls, 40 healthy volunteers, were tested in ELISA for IgG or IgM reacting with any of three recombinant P. vivax proteins. The antigens used, representing the parasite's major merozoite surface protein (MSP), circumsporozoite surface protein (CSP) and Duffy-binding protein (DBP), had all been expressed in an Escherichia coli system and purified. The ELISA results were recorded as optical densities (OD). The highest ratio observed between the mean OD for a malaria serum and that for a control serum was that for IgG against MSP, although CSP gave a higher ratio than MSP or DBP in the IgM ELISA. In the ELISA for IgG, the OD for MSP were found to be correlated with those for DBP (r = 0.53; P < 0.5) but the OD for CSP were not correlated with those for MSP or DBP. As the most intense reactions observed were those between the IgG from the malaria sera and the recombinant MSP, the latter antigen may be useful in diagnostic tests and as a component of any vaccine used to protect against P. vivax malaria.

Adult↗