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Biomedical subjects

K Sun

Publications and source records attributed to K Sun.

171 records · Page 10Linked to original sources
PubMed1985

Chromosomal site of hepatitis B virus (HBV) integration in a human hepatocellular carcinoma-derived cell line.

The single site of integration of hepatitis B virus in the human hepatocellular carcinoma cell line Hep 3B 2-1/7 was found to segregate with human chromosome 12 in somatic cell hybrids. Analysis of metaphase spreads of Hep 3B 2-1/7 following in situ hybridization with pHBV revealed integration at 12q13----q14, a location that coincides with a fragile site, fra (12q13). The possible significance of this location to the development of hepatocellular carcinomas is discussed.

Animals↗
PubMedDate not supplied

Percutaneous closure of perimembranous ventricular septal defects with the eccentric Amplatzer device: multicenter follow-up study.

Using an Amplatzer membranous eccentric occluder, 186 patients with an average weight of 43.5 kg (range 12.5-77) underwent attempted catheter closure of a perimembranous venricular septal defect (PMVSD). Their age ranged from 3 to 51 years, with the an average age being 15.9 years. The patients were divided into three groups according to morphology of PMVSD: 106 patients with single PMVSD, 63 patients with single PMVSD with aneurysmatic formation, and 17 patients with multiple VSD with aneurysmatic formation. Using angiography, PMVSDs were measured to be between 2.5 and 12 mm, with an average of 5.1 mm. In the third group of patients, we did not measure the size of PMVSD and a device was selected according to the size of entry to the aneurysm. The device was successfully implanted in all patients. The immediate closure rate was 90% in the first group, increasing to 100% at 1 month and remained at that level during follow-up. The immediate closure rate in the second group was 98% and remained the same during follow-up. The immediate closure rate in the third group was 89% and during 1 year of follow-up remained the same. There was no clinical evidence of hemolysis and no incidence of device embolization or bacterial endocarditis after implantation. Before the procedure, all patients showed normal electrocardiogram (ECG) or left ventricle enlargement. After the procedure (at least 3 months later) ECG showed left anterior hemiblock (LAH) in nine patients, complete right bundle branch block in eight patients, and incomplete right bundle branch block in seven patients. A complete heart block (CHB) developed in 2 patients after the procedure (1.07%). The first patient developed LAH immediately after closure and CHB within 24 hours, The heart rate was 28 beats per minute. After treatment with steroids and atropine, CHB changed to sinus rhythm with LAH within 2 months. One year later, the ECG revealed the same findings. The second patient developed CHB immediately after the procedure and was on temporary pacing for 1 week. After 1 month, the patient recovered to sinus rhythm and ECG showed LAH.

Adolescent↗
PubMedDate not supplied

Dexamethasone fails to inhibit the induction of cytosolic phospholipase A(2) expression by interleukin-1beta in cultured primary human amnion fibroblasts.

OBJECTIVE: To investigate the interaction of dexamethasone and interleukin-1beta (IL-1beta) on the expression of cytosolic phospholipase A(2) (cPLA(2)), the enzyme catalyzing the first reaction in the formation of prostaglandins, in cultured primary human amnion fibroblasts. DESIGN AND METHODS: Human amnion fibroblasts were prepared from fetal amnion collected at term and were treated with dexamethasone with or without interleukin-1beta for 24h. Prostaglandin E(2) (PGE(2)) output and cPLA(2) expression in cultured amnion fibroblasts were measured with radioimmunoassay, quantitative real-time polymerase chain reaction, Western blotting and cPLA(2) promoter-driven luciferase reporter gene activity. RESULTS: Both dexamethasone and IL-1beta caused a significant increase in prostaglandin E(2) output, cPLA(2) mRNA and protein expression in cultured human amnion fibroblasts. Both dexamethasone and IL-1beta stimulated cPLA(2) promoter-driven luciferase reporter gene activity. There was no obvious antagonistic or synergistic effect of combined treatment of dexamethasone and IL-1beta on PGE(2) output, cPLA(2) expression or cPLA(2) promoter-driven luciferase reporter gene activity in cultured human amnion fibroblasts. CONCLUSION: The above findings suggest that paradoxically dexamethasone is a stimulator for both prostaglandin synthesis and cPLA(2) expression in human amnion fibroblasts. The interaction between dexamethasone and IL-1beta on prostaglandin synthesis and cPLA(2) expression is neither synergistic nor conventionally antagonistic.

Amnion↗
PubMedDate not supplied

Glucocorticoid actions and metabolism in pregnancy: implications for placental function and fetal cardiovascular activity.

The isoforms of the enzyme 11beta hydroxysteroid dehydrogenase (11betaHSD) are expressed in placental tissue and fetal membranes. The two major isoforms, 11betaHSD-1 and 11betaHSD-2, are compartmentalized discretely, and regulated differentially by steroids (oestrogen, progesterone), activators of cAMP pathway, and nitric oxide. 11BetaHSD-2 appears important in human pregnancy in regulating the amount of maternal cortisol that crosses the placenta to reach the fetal compartment. On the other hand, 11betaHSD-1 may allow the local conversion of biologically inactive cortisone to biologically active cortisol, particularly within chorion trophoblasts. The localization, regulation, and importance of these isozymes are examined.

11-beta-Hydroxysteroid Dehydrogenases↗
PubMedDate not supplied

Comprehensive two-dimensional gas chromatography for fast screening of wash oils.

Fast screening of wash oils is demonstrated using comprehensive two-dimensional gas chromatography (GCxGC). Wash oils are used in ethylene production plants to minimize compressor fouling. The composition of a wash oil determines its effectiveness in solubilizing heavy hydrocarbons. In particular, the relative amount of 1- and 2-ring aromatics is important. The presence of oxygenates is undesirable because of adverse effects to the process. It is shown that GCxGC is well suited for this application. Species in wash oils are separated and grouped into three bands: a nonpolar aliphatics band, 1- and 2-ring aromatics band, and polyaromatics band. For a given polar secondary column, the spacing between bands in the second dimension can be adjusted in a broad range by selecting a primary column and an oven-temperature-programming rate. Integration of GCxGC peaks is evaluated using a standard GC integration program and a new GCxGC integration program. Consistent results are obtained using both programs for well-separated GCxGC peaks with relative differences for individual peak ranging from 0.04% to 1.6%. Peak responses are integrated by the GCxGC software, and the relative amounts of aromatics content and aliphatics content are estimated by peak response percent with relative standard deviations ranging from 0.15% to 2.8% (n = 3).

Journal Article↗
PubMedDate not supplied

Monocusp valve and transannular patch reconstruction of the right ventricular outflow tract: an experimental study.

Repair of congenital right ventricular outflow tract obstruction often requires reconstruction with a transannular patch to alleviate pulmonary stenosis. Post repair pulmonary insufficiency with right ventricular dilatation and volume overload may result and lead to acute or progressive right heart failure. The use of a monocusp valve has been proposed as a means to prevent this problem. Fresh pericardium is well known to fail clinically, leading to pulmonary insufficiency limiting mid- and long-term results. In a chronic dog model (147 +/- 34 days), three valve types were evaluated: 1) polytetrafluoroethylene (PTFE; n = 9), 2) fresh pericardium (PERI; n = 6), and glutaraldehyde fixed pericardium (GLU; n = 6). Hemodynamics, angiography, and echocardiography were performed at implantation and sacrifice. Gross and microscopic pathology were evaluated. No significant differences were found among the three groups with regard to stenosis as evaluated by echocardiography, measured right ventricular wall thickness, and hemodynamic pressure gradients across the valve. By echocardiography, both PTFE (1 of 9) and GLU (0 of 6) showed less regurgitation than PERI (5 of 6) (p < 0.05). This was confirmed by angiography. PTFE showed less neo-intimal hyperplasia, less thrombus formation, and less calcification than GLU or PERI (p = NS). The PTFE monocusp developed no prohibitive gradients, no early pathologic deterioration, and maintained competence compared with the GLU and PERI groups. Although continued investigation of long-term durability and competence of the PTFE monocusp valve is warranted, both PTFE and GLU values seem to demonstrate less regurgitation than the PERI monocusp valve in an adult dog model of right ventricular outflow tract reconstruction.

Animals↗