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Biomedical subjects

S Y Cho

Publications and source records attributed to S Y Cho.

At least 55 records · Page 3Linked to original sources

Flail aortic valve and acute aortic regurgitation due to spontaneous localized intimal tear of ascending aorta.

This report describes the transesophageal echocardiographic findings of acute severe aortic regurgitation resulting from localized transverse intimal tear of ascending thoracic aorta which could not be suspected as a cause of flail aortic valve preoperatively. In patients with chest pain and acute aortic regurgitation associated with flail aortic valve, localized intimal tear of aorta should be considered as a possible cause of flail aortic valve.

Aortic Rupture↗

The enhanced effect of a hexameric deoxyriboguanosine run conjugation to CpG oligodeoxynucleotides on protection against allergic asthma.

BACKGROUND: Oligodeoxynucleotides containing a CpG motif (CpG ODNs), as potent inducers of T(H)1 immunity, are considered promising candidates for immune modulation in asthma. We have previously demonstrated that conjugation of a hexameric deoxyriboguanosine run to the 3' terminus (3' dG(6)-run) of phosphodiester (PE) CpG ODNs enhanced their immuno-stimulatory activities in vitro. OBJECTIVE: This study aimed to evaluate the effect of a 3' dG(6)-run conjugation to PE or phosphorothioate (PS) CpG ODNs on protection against murine allergic asthma in vivo. METHODS: Balb/c mice were sensitized to ovalbumin by intraperitoneal injection with or without CpG ODNs (PS CpG ODNs, PE CpG ODNs, and those with 3' dG(6)-run) and subsequently challenged with ovalbumin. We evaluated airway hyperresponsiveness, eosinophil proportion in bronchoalveolar lavage fluid, airway inflammation, and ovalbumin-specific antibody responses. RESULTS: The conjugation of a 3' dG(6)-run to PE CpG ODNs enhanced the production of IFN-gamma from ovalbumin-specific T(H) cells and prevented the development of asthma in terms of airway hyperresponsiveness, airway eosinophilia, and ovalbumin-specific IgE responses; these effects were comparable to those of PS CpG ODNs. Enhanced effects of the 3' dG(6)-run were also observed in PS CpG ODNs, though they were lower than those in PE CpG ODNs. CONCLUSION: This study suggests that conjugation of a 3' dG(6)-run to CpG ODNs might provide an effective method for immune modulation of allergic asthma.

Animals↗

Moderate dietary fat consumption as a risk factor for ischemic heart disease in a population with a low fat intake: a case-control study in Korean men.

BACKGROUND: Dietary fat intake is associated with the incidence of ischemic heart disease (IHD) in Western countries. In populations in which both the average dietary fat consumption and the incidence of IHD are lower than in Western countries, the association of dietary fat intake with IHD incidence remains unknown. OBJECTIVE: We conducted a case-control study to examine the association of dietary fat with IHD incidence in Korean men. DESIGN: The case group consisted of 108 patients with electrocardiogram-confirmed myocardial infarction or angiographically confirmed (> or =50% stenosis) IHD who were admitted to a university teaching hospital in Seoul, Republic of Korea. The controls were 142 age-matched patients admitted to the departments of ophthalmology and orthopedic surgery at the same hospital. Dietary fat intake was assessed by a nutritionist using a semiquantitative food-frequency questionnaire. Body mass index (BMI), cigarette use, alcohol intake, exercise, and history of disease were determined during an interview and examination. RESULTS: In a univariate analysis, the mean percentages of energy from total fat, saturated fatty acids, and monounsaturated fatty acids were significantly higher in the cases than in the controls. BMI, smoking, and a history of hypertension were associated with the occurrence of IHD. In multiple logistic analyses, total fat intake was a significant risk factor (odds ratio: 1.08 for 1% of energy intake; 95% CI: 1.02, 1.14) after adjustment for BMI and smoking. CONCLUSION: In a population with a relatively low fat intake (19% of energy intake), a moderate increase in total fat intake may be a risk factor for IHD.

Alcohol Drinking↗

CsRn1, a novel active retrotransposon in a parasitic trematode, Clonorchis sinensis, discloses a new phylogenetic clade of Ty3/gypsy-like LTR retrotransposons.

We screened the genome of a trematode, Clonorchis sinensis, in order to identify novel retrotransposons and thereby provide additional information on retrotransposons for comprehensive phylogenetic study. Considering the vast potential of retrotransposons to generate genetically variable regions among individual genomes, randomly amplified polymorphic DNAs (RAPDs) detected by arbitrarily primed polymerase chain reactions were selected as candidates for retrotransposon-related sequences. From RAPD analysis, we isolated and characterized a novel retrotransposon in C. sinensis as the first member of uncorrupted long-terminal-repeat (LTR) retrotransposons in phylum Platyhelminthes. The retrotransposon, which was named Clonorchis sinensis Retrotransposon 1 (CsRn1), showed a genomewide distribution and had a copy number of more than 100 per haploid genome. CsRn1 encoded an uninterrupted open reading frame (ORF) of 1,304 amino acids, and the deduced ORF exhibited similarities to the pol proteins of Ty3/gypsy-like LTR retrotransposons. The mobile activity of master copies was predicted by sequence analysis and confirmed by the presence of mRNA transcripts. Phylogenetic analysis of Ty3/gypsy-like LTR retrotransposons detected a new clade comprising CsRn1, Kabuki of Bombyx mori, and an uncharacterized element of Drosophila melanogaster. With its high repetitiveness and preserved mobile activity, it is proposed that CsRn1 may play a significant role in the genomic evolution of C. sinensis.

Amino Acid Sequence↗

Antioxidant and immunostimulating activities of the fruiting bodies of Paecilomyces japonica, a new type of Cordyceps sp.

Cordyceps is negative for its many biological activities and a tonic for restoring vital functions in traditional Chinese medicine. In an effort to evaluate the pharmacological effects, including the antiaging effect of the fruiting bodies of the cultivated Paecilomyces japonica fungus, a new type of Cordyceps sp. was investigated. This investigation was focused on ultimately revealing its biologically active principles, its effects on free-radical scavenging enzymes, lipid peroxidation, as well as its immunological functions. As a result, both water and methanol extracts were found to cause not only significant increases in rat liver cytosolic SOD, catalase, and GSEH-px activities, but also a significant decrease in MDA production in TBA reactant assay in rats. The extracts also showed immunostimulating activity as measured by carbon clearance, weight-loaded forced swimming performances, and immobilizing stress in mice. Using bioassay-guided systematic fractionation of the extracts, two pure compounds were isolated as active principles from low molecular-weight fraction, a protein-bound polysaccharide was isolated that showed a marked increase in the liver enzyme activities, as well as a significant inhibition of lipid peroxidation.

Adjuvants, Immunologic↗

Effects of Puerariae Flos and Puerariae Radix extracts on antioxidant enzymes in ethanol-treated rats.

This study was performed to investigate the effect of Puerariae Flos (PF) and Puerariae Radix (PR) water extracts on the activities and mRNA expression of three hepatic antioxidant enzymes in ethanol-treated rats. Male Sprague-Dawley rats were divided into four groups, a control, ethanol-treated, ethanol plus PF-treated, and ethanol plus PR-treated group with seven rats per group. Ethanol (25 % v/v, 5 g/kg body weight) was orally administered once a day for 5 weeks. The PF and PR water extracts were supplemented in a diet based on 1.2 g of raw PF or PR/kg body weight/day. Ethanol administration without the PF or PR supplement significantly lowered the activities of hepatic Cu/Zn SOD and catalase (CAT), whereas it increased the hepatic GSH-Px activity. However, the PF and PR supplementation resulted in a significant increase in the Cu/Zn SOD and/or CAT activities and a significant decrease in the GSH-Px activity in the ethanol-treated rats. The mRNA levels of these antioxidant enzymes in the ethanol-treated rats were normalized to the control level by the PF or PR supplement. The hepatic glutathione content, which was significantly lower in the ethanol-treated group than in the control group, was also normalized to the control level by supplementing with either PF or PR. The PF or PR supplement resulted in lowering the hepatic malondialdehyde to the control level in the ethanol-treated rats.

Animals↗

Enhanced 3D shape recovery using the neural-based hybrid reflectance model.

It is known that most real surfaces usually are neither perfectly Lambertian model nor ideally specular model; rather, they are formed by the hybrid structure of these two models. This hybrid reflectance model still suffers from the noise, strong specular, and unknown reflectivity conditions. In this article, these limitations are addressed, and a new neural-based hybrid reflectance model is proposed. The goal of this method is to optimize a proper reflectance model by learning the weight and parameters of the hybrid structure of feedforward neural networks and radial basis function networks and to recover the 3D object shape by the shape from shading technique with this resulting model. Experimental results, including synthetic and real images, were performed to demonstrate the performance of the proposed reflectance model in the case of different specular effects and noise environments.

Journal Article↗

Molecular cloning and characterization of an antigenic protein with a repeating region from Clonorchis sinensis.

In the course of immunoscreening of Clonorchis sinensis cDNA library, a cDNA CsRP12 containing a tandem repeat was isolated. The cDNA CsRP12 encodes two putative peptides of open reading frames (ORFs) 1 and 2 (CsRP12-1 and -2). The repetitive region is composed of 15 repeats of 10 amino acids. Of the two putative peptides, CsRP12-1 was proline-rich and found to have homologues in several organisms. Recombinant proteins of the putative peptides were bacterially produced and purified by an affinity chromatography. Recombinant CsRP12-1 protein was recognized by sera of clonorchiasis patients and experimental rabbits, but recombinant CsRP12-2 was not. One of the putative peptide, CsRP12-1, is designated CsPRA, proline-rich antigen of C. sinensis. Both the C-termini of CsRP12-1 and -2 were bacterially produced and analysed to show no antigenicity. Recombinant CsPRA protein showed high sensitivity and specificity. In experimental rabbits, IgG antibodies to CsPRA was produced between 4 and 8 weeks after the infection and decreased thereafter over one year. These results indicate that CsPRA is equivalent to a natural protein and a useful antigenic protein for serodiagnosis of human clonorchiasis.

Amino Acid Sequence↗

Incidence patterns of vivax malaria in civilians residing in a high-risk county of Kyonggi-do (province), Republic of Korea.

The characteristics of vivax malaria epidemics along the demilitarized zone (DMZ) in the Republic of Korea has been established by the early surveillance data. To further characterize the epidemic, data of civilian patients microscopically diagnosed with malaria from 1995 through 2000 were analyzed in Yonchon-gun (county). Malaria incidence was greater in male civilians > 30 years of age (p < 0.05). The annual parasite index was significantly higher in those living in the administrative areas (Myeon) traversed by DMZ than those living in Myons not traversed by DMZ (p < 0.05). Analysis according to the distance (4 to 14 km) from DMZ showed that people living in villages close to DMZ had higher annual parasite indices than those living in villages remote from DMZ (p for trend < 0.05). Civilians living in Myeons with plains and located in northwestern part of the county had higher annual parasite indices than those living in hilly Myeons located in southeastern part of the county (p for trend < 0.05). These findings suggest that the contraction of vivax malaria is related with night-time outdoor activities, and that the distance from DMZ is a risk factor. In this area, the flying distance of infected vector mosquitos can explain the annually repeating occurrence of civilian cases.

Adolescent↗

Postinfarction left ventricular rupture misdiagnosed ruptured intramural hematoma of aorta.

Left ventricular rupture is a fatal complication of acute myocardial infarction, however accurate preoperative diagnosis is still difficult. We experienced a postinfarction left ventricular rupture patient whose symptoms and radiologic findings mimicked those of acute intramural hematoma of the aorta. Upon emergency operation, he was proven to have a postinfarction LV rupture and underwent successful surgery. We herein report the case with a brief review of the literature.

Aortic Diseases↗

Incidence and characterization of Listeria spp. from foods available in Korea.

A total of 410 domestic Korean food samples were analyzed for the presence of Listeria spp. by the conventional U.S. Department of Agriculture protocol, and presumptive strains were identified by morphological, cultural and biochemical tests according to Bergey's manual and confirmed by API-Listeria kit. Among the total 410 food samples, 46 samples (11.2%) were found to be contaminated with Listeria species. Among the 46 strains of Listeria spp. isolates, 8 strains (17.42%) for Listeria monocytogenes, 3 strains (6.5%) for Listeria seeligeri, 33 strains (71.7%) for Listeria innocua, and 2 strains (4.4%) for Listeria welshimeri were identified, respectively. Also, only beef, chicken, pork, frozen foods, and sausage were contaminated with L. monocytogenes, and the other products were free of L. monocytogenes. Of 46 Listeria spp. isolates, L. innocua (71.7%) was the most predominantly isolated in a variety of foods compared to other Listeria spp. An in vitro virulence assay for Listeria spp. using myeloma and hybridoma cells from murine and human sources was performed. The result showed that only L. monocytogenes killed approximately 95 to 100% hybridoma cells after 6 h and the other Listeria species, such as L. innocua, L. seeligeri, and L. welshimeri strains had about 0 to 10% lethal effect on hybridoma cells. Also, an antibiotic susceptibility test showed that Listeria spp. isolates were very susceptible to the antibiotics tested, except for nalidixic acid. Also, serotyping results showed 75% of L. monocytogenes isolates from beef, chicken, and frozen pizza belonged to serotype 1 and 25% from sausage were type 4.

Animals↗

Stenting with intravenous abciximab infusion for the treatment of left main coronary artery thrombosis during coronary angioplasty.

A 67-year-old female patient complained of exertional precordial chest pain with radiation to the left shoulder occurring over a two-month period. An acute non-Q wave anterior myocardial infarction was diagnosed. On the third day of admission, coronary angiography revealed two-vessel disease with 73% luminal narrowing of the proximal left anterior descending coronary artery and 50% luminal narrowing of the mid-right coronary artery. The initial attempt to implant a NIR stent (Boston Scientific/Scimed, Inc., Maple Grove, Minnesota) was unsuccessful. We report on the successful rescue implantation of two MAC (Maximum Arterial re-Creation) stents (Advanced Medical Technologies, Germany), in conjunction with the infusion of abciximab for the treatment of an abrupt closure due to thrombus of the left main coronary artery.

Abciximab↗

Long-term results with St. Jude Medical and CarboMedics prosthetic heart valves.

BACKGROUND AND AIM OF THE STUDY: The clinical evaluation and comparison of St. Jude Medical (SJM) and CarboMedics (CM) prosthetic heart valves implanted between 1988 and 1997 is presented. METHODS: In total, 648 SJM valves were implanted in 641 patients, and 601 CM valves in 591 patients. There were 684 mitral valve replacements, 256 aortic valve replacements, 252 mitral and aortic (double) valve replacements, 16 triple valve replacements, and 41 other tricuspid-related valve replacements. Total follow up was 98%. The overall incidence of valve-related events was compared before and after establishment of a 'valve clinic' in 1993. RESULTS: The overall hospital mortality was 3.4%; late mortality was 8.2%. The five- and ten-year survival for all patients was 92.1% and 86.2%, respectively. There were 31 episodes of thromboembolism in 27 patients (including valve thrombosis in three), 21 episodes of bleeding events in 20 patients, and 18 re-replacements of implanted valves. No structural valve deterioration was observed. Freedom from thromboembolism was 97.8% at five years and 96.3% at ten years; freedom from bleeding episodes was 98.1% and 97.6%, respectively. In terms of hospital and late mortality, and incidence of thromboembolism, hemorrhagic episodes and structural valve failure, no statistically significant differences were found between the SJM and CarboMedics patient groups. Freedom from thromboembolism was 96.7% at five years before initiation of an intensive follow up program, and 99.0% thereafter (p = 0.031). In contrast, freedom from bleeding episodes fell from 99.3% to 96.1% during the same time period (p = 0.0004). CONCLUSION: Both the SJM and CM prosthetic heart valves performed well in our study, and no discernible differences in clinical performance of the two valves were detected. The intensive follow up program resulted in a reduced incidence of thromboembolism, but an increased number of bleeding complications. An optimum anticoagulation regimen to manage these two conflicting problems has yet to be elucidated.

Adolescent↗

p67 isoform of mouse disabled 2 protein acts as a transcriptional activator during the differentiation of F9 cells.

The mouse disabled 2 (mDab2) gene is a mouse homologue of the Drosophila disabled gene and is alternatively spliced to form two isoforms, p96 and p67. Although p96 has been known to regulate the Ras-Sos G-protein signal transduction pathway by interacting with Grb2, little is known about the biological function of p67. Recent studies have shown that the expression of mDab2 is markedly up-regulated during the retinoic acid (RA)-induced differentiation of F9 cells, suggesting another role for mDab2 in cell differentiation [Cho, Lee and Park (1999) Mol. Cells 9, 179-184). In the present study, we first elucidated the biological function of p67 isoform of mDab2 and identified its binding partner. Unlike p96, p67 largely resides in RA-treated F9 cell nuclei. In this system, p67 interacts with mouse androgen-receptor interacting protein 3, termed the mDab2 interacting protein, which acts as a transcriptional co-regulator. By using a fusion protein with a heterologous DNA-binding domain (GAL4), we showed that p67 had an intrinsic transcriptional activation function. These results suggest that mDab2 p67 may function as a transcriptional co-factor for certain complexes of transcriptional regulatory elements involved in the RA-induced differentiation of F9 cells.

3T3 Cells↗

Randomized comparison of elective stent implantation and coronary balloon angioplasty guided by online quantitative angiography and intracoronary Doppler. DESTINI Study Group (Doppler Endpoint STenting INternational Investigation).

BACKGROUND: The purpose of this study was to compare long-term outcomes of coronary stenting in all lesions (elective stenting) or only in lesions with inadequate morphological and functional results after balloon angioplasty (guided PTCA). METHODS AND RESULTS: Treatment of multivessel disease, with any lesion length and vessel size, was allowed provided that all lesions were suitable for stent implantation. Patients were randomized to elective stent implantation (n=370) or guided PTCA (n=365). An optimal PTCA result (residual diameter stenosis </=35%, coronary flow reserve measured with a Doppler guidewire >2.0, absence of threatening dissections) was achieved in 166 lesions (43%). The remaining 218 lesions underwent stent implantation (provisional stenting). Final residual diameter stenosis was lower in the elective and provisional stent groups (9.3% and 10.2%) than in the optimal PTCA group (24.8%, P:<0. 00001). On an intention-to-treat analysis, the probability of >/=1 major adverse cardiac event at 12 months was 17.8% in the elective stenting group and 18.9% in the guided PTCA group (20.1% for optimal PTCA and 18.0% for the provisional stenting subgroup, P:=NS). The incidence of repeat target lesion revascularization at 1 year was 14. 9% in the elective stent group and 15.6% in the guided PTCA group (17.6% for optimal PTCA and 14.1% for the provisional stenting subgroup, P:=NS). CONCLUSIONS: When balloon angioplasty is guided by online quantitative angiography and Doppler-derived coronary flow reserve, with provisional stenting reserved for suboptimal results, early and late clinical outcomes are comparable to those achieved by elective stenting of all patients.

Angiography↗

Genomic organization and promoter analysis of mouse disabled 2 gene.

The mouse disabled 2 (mDab2) gene is a mouse homolog of the Drosophila disabled gene. It is markedly up regulated in retinoic acid (RA)-treated F9 cells, suggesting a role for mDab2 in the cell differentiation. To elucidate the molecular mechanisms that regulate RA-treated F9 cells specific expression of mDab2, we cloned and analyzed its genomic structure. The mDab2 gene spans over 55 kilobases and has 13 exons. The transcription start site, mapped by primer extension and 5'RACE, was located at 53 base pairs (bp) upstream of the most 5'-end of the published cDNA. Using reporter gene transfection analysis, we found that a 1-kb mDab2 5'-flanking sequence directed a high level of promoter activity in RA-treated F9 cells but not in untreated cells. Further deletion and mutation analyses identified a direct repeat of 5'-AGGAGGCGC-3' motif as novel positive regulatory element. Gel retardation assay showed that this element was needed to form specific DNA-protein complexes with factors present in RA-treated F9 cell extracts.

Adaptor Proteins, Signal Transducing↗