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Biomedical subjects

E Koh

Publications and source records attributed to E Koh.

At least 19 recordsLinked to original sources
PubMed2006

[Open stent-grafting for the distal arch aneurysm using a new delivery sheath].

Surgical graft replacement of the distal aortic arch aneurysm has been known to have rather poor outcome. Open stent-grafting has been employed in many institutions, but several complications have been reported. Especially, embolism of the distal artery by debris of aneurysmal wall is a serious complication. Therefore we have developed and applied a new delivery sheath. The sheath is constructed with a ready-made delivery sheath and a part of a ready-made tracheostomy tube. That is called "balloon sheath". Five patients underwent distal arch stent-grafting using the device, all of whom had excellent result. The merits of the sheath are smooth delivery of stent-graft and less invasiveness for aortic wall. The new device is considered to be able to prevent aortic wall injury and peripheral embolic complication during insertion of stent-graft.

Aged↗
PubMed2006

[Ascending aortic dissection associated with pulmonary contusion caused by blunt trauma].

A 77-year-old female tumbled and struck her front chest wall twice. After the event, hemosputum was observed and she complained of slight chest discomfort. As chest pain continued to worsen a week after the event, she was transferred to our hospital. The computed tomography (CT) revealed an ascending aortic dissection and bilateral pulmonary contusion. In the intensive care unit (ICU), antihypertensive therapy was given immediately and delayed surgical repair was planned because of pulmonary contusion. Twenty days after the event, proximal hemiarch replacement was performed. Postoperative course was uneventful without any complication. She was discharged on the 23rd day after the operation.

Aged↗
PubMed2005

[Clinical evaluation of hydrocolloidal dressing in 147 patients undergoing cardiovascular surgery].

Recent evidence has suggested that a moist environment plays an important role in wound healing. Karayahesive, one type of hydrocolloidal dressing, contains natural karaya gum as a hydrophilic gel. We applied hydrocolloidal dressing to operative wounds in 147 patients who underwent cardiovascular surgery from April 2001 through August 2002 to evaluate its clinical usefulness. The dressing was kept on the wounds for 7 days after operation, but was immediately switched to conventional dressing with gauze if there was any problem. A total of 144 patients (98%) had no wound chest infections. Good wound healing was obtained with only 1 dressing, removed 7 days after operation, in 128 patients (87%). In 19 patients (13%), the hydrocolloidal dressing was switched to conventional dressing. In 13 of these patients the hydrocolloidal dressing dissolved naturally or exudation occurred; clinically, there were no local problems; however, 3 patients had infection, 2 had fat necrosis, and 1 had burn injury caused by electrocautery. No patients had skin problems caused by this dressing. We conclude that hydrocolloidal dressing can be used safely and effectively in patients undergoing cardiovascular surgery and reduce the workload of healthcare workers.

Adult↗
PubMed2004

[Primary cardiac malignant lymphoma diagnosed intraoperatively during aortic valve repair; report of a case].

A 58-year-old male who complained of chest oppression on effort was diagnosed as aortic regurgitation by echocardiography. The cardiac catheterization was showed moderate aortic regurgitation. He was referred to our hospital for aortic valve replacement. We considered preoperatively that the aortic regurgitation is due to infective endocarditis or aortitis syndrome. We have not noticed cardiac tumor at all until aortic valve replacement. Postoperative pathological diagnosis of the tumor was malignant lymphoma. The tumor had a characteristic architecture of a cardiac MICE (mesothelial/monocytic incidental cardiac excrescence). After the operation, additional chemotherapy using doxorubicin and cysplatin was performed. The patient has been doing well for 5 years after operation.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2004

[Ruptured syphilitic ascending aortic aneurysm; report of a case].

Syphilitic cardiovascular disease has become a rarity today. It most commonly affects the ascending aorta and aortic arch. A case is reported of a 50-year-old female with a ruptured syphilitic ascending aortic aneurysm who underwent an emergency operation. The patient was emergently admitted with complaint of severe dyspnea, circulatory shock due to cardiac tamponade was observed in the emergency room. Bentall's procedure was performed. Intraoperative findings showed multi-cystic dilatation of an aortic root. Penetration was existed on right side posterior wall of an aortic root. Postoperative pathological examination of the aneurysmal wall revealed the characteristic finding of syphilitic aortitis. The postoperative course was uneventful and the patient has been doing well at period of 3 years after operation.

Aneurysm, Ruptured↗
PubMed2003

[Bilateral coronary ostial stenoses with aortic regurgitation in a patient with syphilitic aortitis].

Syphilitic aortitis is now rare in developed countries and is sometimes overlooked. A 61-year-old man with bilateral coronary ostial stenoses (#5:90%, #1:99%) and Sellers III/IV aortic regugitatioin (AR) induced by syphilitic aortitis presented with chest pain. Preoperative rapid plasma reagin titer and Treponema pallidum hemagglutination test were strongly positive, 256 fold and 191.25 C.O.I., respectively. Aortic valve replacement (AVR) and coronary artery bypass grafting (CABG) with bilateral internal thoracic arteries (ITA) was performed successfully. The angiographic features as follows: 1) coronary artery stenosis is generally limited to the ostia, 2) the grade of stenosis is almost always more than 90%, 3) AR is frequently associated with coronary ostial stenosis. CABG should be performed with ITA, not saphenous vein grafts, to avoid occlusion of the ostium of the saphenous vein graft by syphilitic aortitis. Retrograde cardioplegia should be performed if ostial stenosis is severe.

Aortic Valve↗
PubMed2003

[Combined operation for left ventricular aneurysm and ventricular septal perforation with normal coronary arteries; report of a case].

We experienced a rare case of left ventricular aneurysm (LVA) and ventricular septal perforation (VSP) with normal coronary arteries, and had a good outcome by undergoing Dor procedure and direct closure of VSP individually. A 68-year-old female was printed out cardiac systolic murmur. Echocardiogram revealed LVA and VSP, but coronary arteriogram showed no significant stenosis. The apex was incised longitudinally, lateral and parallel to the interventricular groove. VSP was directly closed by 2 pieces of 3-0 polypropylene suture with felt strip. Purse-string stitch with 3-0 polyester suture around the transitional zone between fibrotic tissue and viable tissue was secured to firm fibrous tissue. The residual orifice was closed with an elliptical composite patch of equine pericardial patch and polyester velour with 3-0 polypropylene suture. We considered based on the operative finding that myocardial infarction (MI) led to LVA and VSP. Coronary thrombosis rather than coronary spasm may have provoked MI because spasm provocative test was negative.

Aged↗
PubMed2002

[Surgical repair of left ventricular free wall rupture using layered fibrin glue sheet and fibrin glue; report of a case].

A 57-year-old man with acute myocardial infarction (#13:90%, #6-#8:75%) was admitted to our hospital after the administration of tissue plasminogen activator. Three hours' after emergent percutaneous transluminal coronary angioplasty, he developed left ventricular free wall rupture in the left circumflex artery area. After bleeding was completely controlled by aortic cross clamping, a three-layered of fibrin glue sheet (TachoComb) with fibrin glue was extensively applied to the ruptured site including the infarcted area. He was discharged on the 25th postoperative day and underwent coronary artery bypass grafting to the left anterior descending artery three weeks later. This experience suggests that the layered TachoComb and fibrin glue are effective for left ventricular free wall rupture.

Coronary Artery Bypass↗
PubMed2001

Mutations that affect dimer formation and helicase activity of the hepatitis C virus helicase.

Interaction between viral proteins is necessary for viral replication and viral particle assembly. We used the yeast two-hybrid assay to identify interactions among all the mature proteins of the hepatitis C virus. The interaction between NS3 and NS3 was one of the strongest viral protein-protein interactions detected. The minimal region required for this interaction was mapped to a specific subdomain of 174 amino acids in the N terminus of the helicase region. Random mutations in the minimal region were generated by PCR, and mutants that failed to interact with a wild-type minimal fragment were isolated using the yeast two-hybrid assay as a screen. Three of these mutations resulted in a reduction or a loss of interaction between helicases. Analytical gel filtration showed that in the presence of an oligonucleotide, wild-type helicases form dimers whereas the mutants remain mostly monomeric. All three mutants were partially or almost inactive when assayed for helicase activity in vitro. Mixing a mutant helicase (Y267S) with wild-type helicase did not dramatically affect helicase activity. These data indicate that dimerization of the helicase is important for helicase activity. The mutations that reduce self-association of the helicase may define the key residues involved in NS3-NS3 dimerization.

Amino Acid Sequence↗
PubMed2001

[Effect of autologous platelet-rich plasma (PRP) in cardiac surgery].

Autologous platelet-rich plasma (PRP) was harvested before cardiopulmonary bypass (CPB). After heparin neutralization, it was returned to patients. The purpose of this study was to examine platelet function and the amount of blood loss and blood transfusion after transfusion of PRP. Twenty-eight patients undergoing elective coronary artery bypass grafting and other procedures were divided into three groups: group A; patients undergoing CAGB between May and October 1997 (n = 10), group B; patients undergoing other between May and October 1997 (n = 8), group C; patients undergoing CAGB before May 1997 (n = 10). Blood cell count, platelet aggregation in response to ADP, and platelet adhesion were measured before CPB, just after CPB, after infusion of protamine and PRP, 24 hrs after CPB and 48 hrs after CPB. Blood loss and blood transfusion in group. A and group C were examined after CPB. There was no significant difference in platelet count between group A and group B. There was significant difference in platelet aggregation in group A. There was no significant difference in blood loss after CPB between group A and group C, but there was a significant difference in blood transfusion between group A and group C. These results suggest that PRP was useful to preserve platelet function and to decrease blood loss after CPB in cardiac surgery.

Blood Transfusion, Autologous↗
PubMed2000

Fas-mediated apoptosis in adriamycin-induced cardiomyopathy in rats: In vivo study.

BACKGROUND: The precise molecular mechanism of Adriamycin-induced cardiomyopathy (ADR-CM) is still unknown. We address the demonstration of apoptotic myocardial cell death and the apoptosis-inducing molecules in ADR-CM induced in rats. METHODS AND RESULTS: Until 8 weeks after the first administration of ADR, there was no increase in the number of labeled cells by terminal deoxynucleotidyl transferase assay (TUNEL method). Apoptotic indices increased significantly at weeks 9 and 10 in hearts of the ADR-treated group but not in those of the control group (0.42+/-0.12% versus 0.10+/-0.02% and 0.86+/-0.11% versus 0.09+/-0.04% at weeks 9 and 10, respectively). DNA ladder formation was also observed in the myocardial tissues during the late stages of the ADR-CM of rats. There was no significant difference in expression of p53 gene between the ADR group and the control group at either the message or the protein level. An overexpression of Fas antigen was shown in myocardial cells of ADR-treated hearts at weeks 9 and 10 by both Western blotting and immunofluorescent staining. Furthermore, we confirmed that neutralization of anti-Fas ligand antibody inhibited ADR-induced apoptosis. CONCLUSIONS: Apoptotic cell death was observed in the hearts of ADR-CM rats, and the number of apoptotic myocardial cells increased with the deterioration of morphological findings and cardiac function, indicating that apoptosis may be an important mechanism of loss of myocardial cells and cardiac dysfunction in ADR-CM. Apoptosis in ADR-CM rats is not p53-dependent but rather is executed through a Fas-mediated pathway.

Animals↗
PubMed2000

A genetic screen to identify genes that rescue the slow growth phenotype of c-myc null fibroblasts.

The c-myc gene is frequently over-expressed in human cancers and is involved in regulation of proliferation, differentiation and apoptosis. c-Myc is a transcription factor that acts primarily by regulating the expression of other genes. However, it has been very difficult to identify bona fide c-Myc target genes that explain its diverse biological activities. The recent generation of c-myc deficient Rat1A fibroblasts with a profound and stable growth defect provides a new system to search for genes that can substitute for c-myc in proliferation. In this study, we have attempted to identify genes that rescue the slow growth phenotype of c-myc null cells through introduction of a series of potent cell cycle regulatory genes and several retroviral cDNA expression libraries. None of the candidate genes tested, including SV40 T-antigen and adenovirus E1A, caused reversal of the c-myc null growth defect. Furthermore, extensive screens with high-complexity retroviral cDNA libraries from three different tissue sources revealed that only c-myc and N-myc rescued the c-myc null slow-growth phenotype. Our data support the notion that there are no functional equivalents of the myc family of proto-oncogenes and also suggest that there are no c-Myc-activated genes that alone can substitute for c-Myc in control of cell proliferation.

Adenovirus E1A Proteins↗
PubMed2000

Determination of ethyl carbamate in some fermented Korean foods and beverages.

Ethyl carbamate has been associated with cancer for several decades. It is mainly found in fermented foods and beverages. In view of the importance of fermented foods in the Korean diet and the significant level of ethyl carbamate expected, we determined ethyl carbamate concentrations in some of the staple food items and estimated the daily intake for the Korean population. Ethyl carbamate in commercial samples of kimchi, soy sauce, vinegar, soybean paste, and alcoholic beverages were determined by gas chromatography-mass spectrometry/selective ion monitoring (GC-MS/SIM). Homemade soy sauce and kimchi were also analysed. The maximum ethyl carbamate concentrations observed were 73 micrograms/kg in soy sauce, 7.9 micrograms/kg in soybean paste, 2.5 micrograms/l in vinegar, 16.2 micrograms/kg in kimchi and 15.4 mu/l in Korean traditional alcoholic beverages. Combining these values with the average daily food intake data, we estimated that the maximum daily exposure of Korean population to ethyl carbamate is 2.8 micrograms/day, which is not a negligible amount considering the 'virtually safe dose' derived by animal experiment ranges between 1.2 and 4.8 micrograms/day. It would be desirable to closely monitor ethyl carbamate levels in Korean foods and to find ways to reduce the daily intake.

Alcoholic Beverages↗
PubMed1999

Differential expression of nitric oxide synthase in human stomach cancer.

The level of expression and cellular localization of isoenzymes of nitric oxide synthase (NOS) was detected in human stomach tumor tissues. Tumor tissues showed 70% higher activity of NOS than that of normal tissues (P < 0.01). Poorly differentiated adenocarcinoma tend to have higher activity (P < 0.05) than well differentiated and moderately differentiated tumor tissues. Aminoguanidine (AG), 2-amino-5,6-dihydro-6-methyl-4H-1,3-thiazine (AMT), NG-monomethyl-L-arginine (L-NMMA), and Nomega-nitro-L-arginine (L-NNA) inhibited NOS activity in tumor tissues by 18, 14, 11 and 13%, respectively. The TNF-alpha mRNA expression was correlated with the inducible NOS (iNOS) level, which was high in adenocarcinomas and low in normal tissues. Tumor tissues showed higher expression of iNOS in gland epithelial cells but the level of eNOS was significantly decreased with an exception of concentrated localization in the proliferating capillary endothelium. These results revealed that isoforms of NOS might contribute differentially to growth and progression of human stomach tumor.

Adult↗
PubMed1999

Spermatogenic ability is different among males in different Y chromosome lineage.

It is a controversial question whether sperm concentrations in humans are changing. Several researchers have reported on environmental factors affecting sperm quality, but the influence of genetic factors is still not fully understood. In this study, we examined the relationship between Y chromosome haplotypes and sperm concentration in fertile males. In addition, we determined the haplotypes of azoospermic patients. The results show that the mean sperm concentration correlates with Y chromosome type. Moreover, the occurrence of azoospermia is related to one particular Y chromosome lineage. Thus, males with a certain haplotype are at a disadvantage for fathering children. The difference of spermatogenic ability among men is important not only in pursuing male competition as in the past but also as relates to the future of modern human males.

Fertility↗