Biomedical subjects

Y M Choi

Publications and source records attributed to Y M Choi.

5 recordsLinked to original sources

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↗