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Y M Choi

Publications and source records attributed to Y M Choi.

54 records · Page 3Linked to original sources
PubMed1997

Lack of interactions between amyloid precursor protein and hydrophilic domains of presenilin 1 and 2 using the yeast two hybrid system.

Mutations in the two related genes, presenilin 1 (PS1) and presenilin 2 (PS2), which are predicted multispanning membrane proteins, are responsible for the majority of early-onset familial Alzheimer's disease (FAD). To demonstrate direct interactions between presenilins (PS) and amyloid precursor protein (APP), the authors utilized a yeast two-hybrid system. Various hydrophilic domains derived from PS and those of APP were coexpressed in yeast and tested for the interaction. No detectable interactions were found in any PS/APP set examined. The authors' studies suggest that PS and APP do not interact through their hydrophilic domains in yeast, raising the possibility that interaction may occur indirectly or require proper conformation or subunit formation.

Alzheimer Disease↗
PubMed1996

Exogenous pulmonary surfactant replacement therapy in a neonate with pulmonary hypoplasia accompanying congenital diaphragmatic hernia--a case report.

Pulmonary hypoplasia(PH) commonly occurs in association with oligohydramnios and other congenital anomalies, especially congenital diaphragmatic hernia (CDH). Pulmonary hypoplasia is an important factor, as persistent pulmonary hypertension, in the prognosis of CDH. In some reports, there is a decrement of pulmonary surfactant in PH accompanying CDH. Recently, there are some reports that exogenous pulmonary surfactant therapy is effective in experimental animal model and neonatal respiratory distress with PH. We report a case of a 5 day-old male neonate, who had shown dyspnea and diagnosed as left pulmonary hypoplasia accompanying CDH. The CDH was surgically treated and the ipsilateral PH, with intratracheal administration of exogenous pulmonary surfactant postoperatively. After exogenous pulmonary surfactant application, the left lung volume was increased on chest roentgenogram and lung perfusion scan findings, and there was an improvement in oxygenation and clinical manifestations. We suggest that postoperative exogenous pulmonary surfactant replacement therapy is effective in the case of PH and further trials are needed to clarify the optimal dose and timing of supplementation of surfactant for treatment of infants with PH accompanying CDH.

Hernias, Diaphragmatic, Congenital↗
PubMed1996

Contact toxicity of permethrin-impregnated military uniforms to Culex pipiens (Diptera:Culicidae) and Phlebotomus papatasi (Diptera: Psychodidae): effects of laundering and time of exposure.

The effects of laundering and time of exposure on the insecticidal activity of military uniform fabric impregnated with permethrin at 0.125 mg active ingredient (AI)/cm2 are reported from susceptibility tests with laboratory-reared mosquitoes, Culex pipiens, and sand flies, Phlebotomus papatasi. Knockdown/mortality resulting from exposure of groups of female insects for periods of 1, 3, 5, 7, and 10 min was recorded and compared among 5 different treatment/wash groups (untreated/unwashed, treated/unwashed, treated/1-wash, treated/2-wash, treated/3-wash). Laundering was by machine washing with detergent and warm water followed by hot-air machine drying. Post-exposure assessments at intervals from 0 to 60 min and at 24 h showed that knockdown for each exposure time and wash group was initially low but increased steadily during the first hour post-exposure. Sand flies were less sensitive than mosquitoes to knockdown during the first 60 min after contact with treated/unwashed fabric; however, 24-h mortality rates for sand flies were higher as compared with mosquitoes. The permethrin remaining after a 3rd wash had little knockdown effect on mosquitoes but was toxic to sand flies at each of the 5 exposure times. Significant reductions in the knockdown effectiveness of permethrin-treated fabric to mosquitoes and sand flies was associated with single and repeated washings of the fabric.

Animals↗
PubMed1996

Induction chemotherapy with idarubicin plus N4-behenoyl-1-beta-D-arabinofuranosylcytosine in acute myelogenous leukemia: a newly designed induction regimen--a prospective, cooperative multicenter study.

This report describes the results of induction chemotherapy with idarubicin (IDA) plus N4-behenoyl-1-beta-D-arabinofuranosylcytosine (BH-AC), a newly designed induction regimen, in cases of previously untreated acute myelogenous leukemia (AML). The study was conducted by the Multicenter Clinical Study Group of the Korean Biologic Response Modifier Society (KBRMS). From March 1994 through January 1995, 40 patients were treated. The median age was 30 years (range, 15 months to 65 years), with a distribution according to the French-American-British (FAB) classification of one MO, nine MI, 15 M2, six M3, four M4, and five M5 patients. Remission induction therapy consisted of IDA 12 mg/m2 intravenously (i.v.) over 30 minutes daily on days 1 to 3, in combination with BH-AC 300 mg/m2 over 4 hours daily on days 1 to 7 (in patients aged 41 to 65 years, BH-AC dosage was decreased to 200 mg/m2/d). Complete remission (CR) was achieved in 30 patients (75%), 22 by the first induction therapy and eight by the second induction therapy. Ten patients (25%) failed to respond to therapy, six due to resistant disease and four due to death caused by aplasia. The time to CR was 30 days, the median granulocytopenic period was 19 days, and the thrombocytopenic period was 24 days. All nonhematologic side effects such as nausea, vomiting, mucositis, skin eruption, liver and cardiac dysfunction, and neurotoxicity, were transient and tolerable. These data indicate an efficacy comparable to that of other combinations of IDA (or other anthracyclines) with cytosine arabinoside (Ara-C) for remission induction in AML.

Adolescent↗
PubMed1995

First-pass accumulation of salicylic acid in gut tissue after absorption in anesthetized rat.

PURPOSE: The purpose of this paper is to report the study on the first-pass accumulation kinetics of salicylic acid (SA) in gut tissue after absorption by simultaneously analyzing drug contents in the lumen, gut tissue, and blood in anesthetized rats. METHODS: Sodium salicylate (5.4 mg as SA) in 0.4 ml normal saline was administered into a closed 10-cm jejunal loop. Drained mesenteric blood from the loop area was collected every minute, while lost blood was replaced through infusion of oxygenated blood from donor rats. At 3, 10, 20, 40, or 60 min after dosing, SA remaining in lumen, accumulating in gut tissue, and appearing in blood were analyzed by HPLC. All the data were fitted into a linear two-consecutive (lumen and gut tissue) first-order kinetic model. RESULTS: After absorption, significant amounts of SA accumulated in gut tissue before appearing in blood, e.g., at 3 or 20 min after dosing, 74.4 or 54.4% of absorbed SA accumulated in gut tissue, respectively. Practically all administered SA was recovered. The estimated mean absorption time from the lumen and mean transit time in gut tissue of SA were 20.4 and 18.5 min, respectively. CONCLUSIONS: The above results indicate that gut tissue may act as a reservoir for drug accumulation during the first pass after oral absorption. Thus, the rate of transport of drug into blood circulation after oral administration may significantly differ from the true rate of absorption through the gut membrane. The potential transport resistance from gut tissue to blood should probably be considered in the modeling of GI absorption.

Animals↗
PubMed1995

Percutaneous drainage of splenic abscess in typhoid fever--a case report.

Salmonella typhi splenic abscesses are a very rare complication of typhoid fever. Splenectomy is the standard surgical treatment for these lesions. But these days, with improvements in imaging techniques, percutaneous drainage of splenic abscesses has been demonstrated to be one of the alternative treatment in selected cases. We report the case of a 7 year-old male, who presented with Salmonella typhi in blood and urine cultures, and a 1: 320 in O titer of Widal test. Ultrasound and computed tomography showed a single splenic abscess, 3 cm in diameter. He was treated with antibiotics, but the symptoms were not relieved. Thus we performed the percutaneous drainage of the splenic abscess under ultrasound guidance. A culture of the aspirated material was positive for Salmonella typhi, and the boy's condition improved. We think that percutaneous drainage of a single lesion was an excellent alternative to surgery, particularly because our patient was young and spleen conservation was desirable.

Abscess↗
PubMed1994

The present status of assisted reproductive technology in Asia-Oceania.

This is a survey on the present status of assisted reproductive technology in the Asia-Oceanic region. The survey formats were sent to the 19-member societies of AOFOG. By the end of August 1991, 11 countries responded: Australia, Egypt, Hong Kong, Israel, Japan, Malaysia, New Zealand, Philippines, Republic of China, Singapore and Thailand. This report is a summary of data from 12 countries including Korea. It comprised of 14 headings: IVF, GIFT, AIH, AID, donor sperm in ART, donor eggs in ART, preembryos from IVF for donation, cryopreservation of eggs, cryopreservation of fertilized eggs and preembryos, research of preembryos, surrogate mothers, additional procedures, quality assurance in reproductive technology and formation of policy for emerging reproductive technology. Each heading is composed of status of regulations, cost and coverage and the results and management of program.

Asia, Southeastern↗
PubMed1994

Human fetal uterine cells: culture, characterization, and analysis of growth factor receptor gene expression.

Peptide growth factors are postulated to have a role in uterine maturation during organogenesis. The purpose of this investigation was to establish a model to study human fetal uterine development. To that end, we describe an in vitro culture system and have characterized the cell types present during the period of uterine maturation. In addition, we evaluated the pattern of growth factor receptor gene expression in these cultured cells. Uteri were dissected from human first and second trimester fetuses (n = 20). Characterization studies were performed against three intermediate filament proteins, cytokeratin, vimentin, and desmin, and against a fibroblast-associated cell surface antigen. Ribonucleic acid was extracted from pure stroma-like cultures, and reverse transcription-polymerase chain reaction (RT-PCR) was used to amplify sequences specific for the epidermal growth factor receptor (EGF-R), fibroblast growth factor receptor (FGF-R), and the insulin receptor (I-R). Two predominant cell types were identified in the cultured fetal tissue: stroma-like cells and clusters of uterine epithelium. Immunofluorescent studies demonstrated positive expression of cytokeratin, vimentin, and a fibroblast-associated antigen in the fetal stroma-like cells, in contrast to adult stromal cells, which consistently expressed only vimentin. Using RT-PCR, the uterine cells were positive for the EGF-R, two forms of the FGF-R, and two forms of the I-R. In conclusion, we provide the first report of a human fetal cell culture system. Characterization studies of fetal stroma-like cells demonstrate immunoreactivity to vimentin, cytokeratin, and a fibroblast antigen, in contrast to the adult stromal cell, which consistently expressed only vimentin. Using RT-PCR, we found that messenger ribonucleic acids for the EGF-R and two forms of both the FGF-R and I-R are expressed. This model may be useful for studying the dynamics of human uterine development in vitro.

Antigens, Surface↗
PubMed1993

Pharmacokinetics and pharmacodynamics of furosemide in protein-calorie malnutrition.

The influence of dietary protein deficiency on pharmacokinetics and pharmacodynamics of furosemide was investigated after i.v. bolus (1 mg/100 g) and oral (2 mg/100 g) administration of furosemide to male Sprague-Dawley rats fed on a 23% (control) or a 5% (protein-calorie malnutrition: PCM) protein diet ad lib. for 4 weeks. After i.v. administration, the mean values of CLR, Vss, and the percentages of dose excreted in 8-hr urine as furosemide were increased 81, 31, and 61%, respectively, in PCM rats when compared with those in control rats, however, CLNR was 54% decreased in PCM rats. The decreased CLNR in PCM rats suggested the significantly decreased nonrenal metabolism of furosemide. The urine volume per g kidney after i.v. administration was not significantly different between the two groups of rats although the amount of furosemide excreted in 8-hr urine per g kidney increased significantly in PCM rats. The diuretic, natriuretic, kaliuretic, and chloruretic efficiencies reduced significantly in PCM rats after i.v. administration. After oral administration, the extent of bioavailability increased considerably from 27.6% in control rats to 47.0% in PCM rats, probably as a result of decreased gastrointestinal and hepatic first-pass metabolism. This was supported by a tissue homogenate study; the amount of furosemide remaining per g tissue after 30-min incubation of 50 micrograms of furosemide with the 9000 x g supernatant fraction of stomach (42.4 vs. 47.9 micrograms) and liver (41.4 vs. 45.9 micrograms) homogenates increased significantly in PCM rats. No significant differences in CLR and t1/2 were found between the control and the PCM rats after oral administration. The 24-hr urine volume and the amount of sodium excreted in 24-hr urine per g kidney increased significantly in PCM rats, and this might be due to a significantly increased amount of furosemide reaching the kidney excreted in urine per g kidney.

Administration, Oral↗
PubMed1991

Effects of phenobarbital and 3-methylcholanthrene pretreatment on the pharmacokinetics and the pharmacodynamics of bumetanide in rats.

The effects of pretreatment with the enzyme inducers, phenobarbital (PB) and 3-methylcholanthrene (3-MC), on the pharmacokinetic and pharmacodynamic parameters of bumetanide were examined in rats. The nonrenal clearance (19.3 vs 29.6 ml min-1 per kg) of bumetanide increased significantly in PB treated rats. This suggested that the nonrenal metabolism of bumetanide is increased by pretreatment with PB, which was supported by significantly increased amounts of bumetanide glucuronide and desbutyl bumetanide excreted in 8-h urine, and reduced amounts of bumetanide remaining per gram of tissue after 30-min incubation of 100 micrograms of bumetanide with the 9000 xg supernatant fraction of liver, stomach, and kidney tissue homogenates in PB treated rats. The contents of hepatic cytochrome P-450 (1.29 vs 2.15 nmol mg-1 protein) and the weights of liver and stomach increased significantly in PB treated rats, suggesting that the metabolizing enzymes for bumetanide are induced by pretreatment with PB. The 8-h urine output per 100 g body weight was not significantly different by pretreatment with PB although the amounts of bumetanide excreted in 8-h urine increased significantly in PB treated rats. It could be explained by the fact that the dose of bumetanide used results in urinary concentrations at the plateau of the concentration-effect relationship. Therefore, the alteration in the urinary excretion rate of bumetanide by pretreatment with PB would not alter the diuretic effect. In 3-MC treated rats, pharmacokinetic and pharmacodynamic parameters were not significantly different and it suggested that the metabolizing enzymes for bumetanide are not induced by pretreatment with 3-MC although the contents of hepatic cytochrome P-450 and the weights of liver and stomach increased significantly by pretreatment with 3-MC.

Animals↗
PubMed1991

Effects of phenobarbital and 3-methylcholanthrene pretreatment on the pharmacokinetics and pharmacodynamics of furosemide in rats.

The effects of pretreatment with the enzyme inducers phenobarbital (PB) and 3-methylcholanthrene (3-MC) on the pharmacokinetic and pharmacodynamic parameters of furosemide were examined in rats. The nonrenal clearance (4.58 versus 6.18 mL/min/kg) increased significantly in PB-treated rats. This suggested that the nonrenal metabolism of furosemide increased by pretreatment with PB. This relationship was supported by the results of a tissue homogenate study; the amounts of furosemide remaining per gram of tissue after 30 min of incubation of 50 micrograms of furosemide with the 9000 x g supernatant fraction of liver, stomach, and kidney tissue homogenates decreased significantly in PB-treated rats. The contents of hepatic cytochrome P-450 (1.29 versus 2.15 nmol/mg protein) and the weights of liver and stomach increased significantly in PB-treated rats, suggesting that the metabolizing enzymes for furosemide are induced by pretreatment with PB. The 8-h urine output per 100 g of body weight increased significantly in PB-treated rats; however, the 8-h urinary excretion of furosemide per 100 g of body weight (797 versus 635 micrograms) decreased significantly in PB-treated rats. Alterations in the urine output might be due to the hormonal alterations in the concentration-effect relationship for furosemide in PB-treated rats. In 3-MC-treated rats, pharmacokinetic and pharmacodynamic parameters of furosemide were not significantly different, indicating that the metabolizing enzymes for furosemide were not induced by pretreatment with 3-MC. However, the contents of hepatic cytochrome P-450 and the weights of liver and stomach increased significantly.

Animals↗
PubMed1990

Oocyte donation program using a simplified hormonal regimen.

It has been well recognized that both the synchronization of luteinizing hormone (LH) surge between the donor and the recipient for normally cycling women and the complex steroid replacement regimen given on a sequential and incremental basis for women with primary or secondary ovarian failure are two important aspects in oocyte donation. In oocyte donation program at SNUH, a simplified hormonal regimen applicable both to normally cycling women and to those with ovarian failure which consisted of administering 2 mg estradiol (E2) valerate orally 3 times a day augmented with 100 mg progesterone (P) in oil intramuscularly daily starting on the day preceding the oocyte retrieval from the donor was utilized. From July 1988 to December 1989 at SNUH, 11 cycles of oocyte donation program in 10 infertile patients were undertaken and 5 patients succeeded in pregnancy.

Adult↗
PubMed1990

Uterine cervical carcinoma: comparison of CT and MR findings.

Thirty patients with uterine cervical carcinoma underwent computed tomography (CT), magnetic resonance (MR) imaging, and surgical exploration. MR imaging was superior to CT in visualization of the tumor. MR imaging had an accuracy of 77% in the assessment of thickness of cervical stromal invasion. The accuracy rates of these modalities for parametrial evaluation were 78% for clinical evaluation, 70% for CT, and 92% for MR imaging. The overall accuracy rates for tumor staging were 70% for clinical evaluation, 63% for CT, and 83% for MR imaging. MR imaging is superior to clinical evaluation and CT in parametrial evaluation and the staging of uterine cervical carcinoma.

Adult↗
PubMed1988

Prenatal diagnosis of a heterozygote of salt wasting congenital adrenal hyperplasia due to 21-hydroxylase deficiency by genetic linkage analysis.

For the purpose of prenatal diagnosis of CAH, genetic linkage analysis by HLA genotyping with lymphocytes and cultured amniotic cells were performed in a family at risk in which two consecutive children had been affected with SW CAH. In addition, the response of serum 17-OHP to intravenous ACTH was determined in obligate carrier parents, and 17-OHP concentration of amniotic fluid was also measured at 16 weeks of gestation. As might be expected, the baseline levels of 17-OHP in obligate parents were significantly higher than that of normal control. Although the post stimulation response of 17-OHP to ACTH in the mother (I-2) was significantly higher than that of normal control, the post stimulation levels of 17-OHP were in normal range in the father (I-1). The 17-OHP level (5.7 ng/ml) in the amniotic fluid showed intermediate value compared to Pang's report (normal less than 30 ng/ml, CAH greater than 12.0 ng/ml) suggesting heterozygote of the fetus. Genetic linkage analysis by HLA genotyping with cultured amniotic cells revealed heterozygote in their fetus (II-3) who has received one chromosome No,6 containing HLA haplotype A24, B40, Cw3 (normal allele for 21-OH) from the father and the other chromosome No,6 containing HLA haplotype A2, Bw62, Cw4 (mutant allele for 21-OH D) from the mother. In conclusion, attempts to detect heterozygote for 21-OH deficiency by ACTH stimulation test were partially successful and prenatal diagnosis of CAH by the hormone studies in ammiotic fluid requires reliable values in normal, heterozygotes and patients group, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Hyperplasia, Congenital↗
PubMedDate not supplied

Association of vitamin D receptor and estrogen receptor gene polymorphisms with bone mass in postmenopausal Korean women.

OBJECTIVE: To examine the relationship between vitamin D receptor (VDR) and estrogen receptor (ER) gene polymorphism and bone mineral density (BMD). DESIGN: Polymorphisms at the VDR FokI and ER PvuII and XbaI gene sites, serum bone-specific alkaline phosphatase, urinary N-telopeptide of type I collagen, and BMD at the lumbar spine and proximal femur were analyzed in 229 postmenopausal Korean women. RESULTS: The distribution of ER PvuII and XbaI and VDR FokI restriction fragment length polymorphisms was as follows: pp 39.3%, Pp 46.3%, PP 14.4%, xx 34.1%, Xx 61.1%, XX 4.8%. ff 17.0%, Ff 43.7%, and FF 39.3%, respectively (upper-case letters signify the absence, and lower-case letters signify the presence of the restriction site). After adjusting for potential confounding factors such as age, body mass index, and menopause duration, ER PvuII was independently associated with BMD at the lumbar spine and XbaI polymorphism BMD at the femoral neck. The lumbar spine BMD in the pp genotype was 7.5% lower than in the PP genotype, and the femoral neck BMD was 4.8% lower in the Xx genotype than in the xx genotype. By itself, the VDR FokI polymorphism was not related to BMD, but by combining the FokI genotype (FF) with ER genotypes, such as ppxx and the PpXx, the difference in the BMD at the Ward's triangle became significant. There were no significant differences in the levels of biochemical markers between the genotypes of three polymorphisms. CONCLUSION: ER polymorphisms, singly and in relation to VDR FokI polymorphism, influence bone mass in Korean women.

Aged↗
PubMedDate not supplied

Isolation and identification of 3-carbamoyloxy-2-phenylpropionic acid as a major human urinary metabolite of felbamate.

A new metabolite of felbamate, isolated from the polar metabolite fraction of a human urine sample, was identified as 3-carbamoyloxy-2-phenylpropionic acid (CPPA) by electron impact and CI/MS of the methyl ester in the isolated fraction. Its presence in the unconjugated free form in two different human urine samples was confirmed by HPLC comparison of retention times with authentic synthetic CPPA and by on-line negative ion HPLC thermospray tandem mass spectrometric techniques. The amount of CPPA in 0-4 hr postdose human urine was estimated to be approximately 12% of the drug-derived substances present in the urine. Some CPPA was also found to be present in dog urine.

Animals↗