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Biomedical subjects

Jung Mi Oh

Publications and source records attributed to Jung Mi Oh.

7 recordsLinked to original sources
PubMed2006

A "silent" polymorphism in the MDR1 gene changes substrate specificity.

Synonymous single-nucleotide polymorphisms (SNPs) do not produce altered coding sequences, and therefore they are not expected to change the function of the protein in which they occur. We report that a synonymous SNP in the Multidrug Resistance 1 (MDR1) gene, part of a haplotype previously linked to altered function of the MDR1 gene product P-glycoprotein (P-gp), nonetheless results in P-gp with altered drug and inhibitor interactions. Similar mRNA and protein levels, but altered conformations, were found for wild-type and polymorphic P-gp. We hypothesize that the presence of a rare codon, marked by the synonymous polymorphism, affects the timing of cotranslational folding and insertion of P-gp into the membrane, thereby altering the structure of substrate and inhibitor interaction sites.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2006

Factors affecting the apparent clearance of tacrolimus in Korean adult liver transplant recipients.

STUDY OBJECTIVE: To identify the factors affecting tacrolimus apparent total body clearance (Cl/F [F = bioavailability]) in adult liver transplant recipients. DESIGN: Population pharmacokinetic analysis using data from a retrospective chart review. SETTING: University-affiliated hospital in Seoul, South Korea. PATIENTS: Fifty-one adult liver transplant recipients who had received tacrolimus after transplantation. MEASUREMENTS AND MAIN RESULTS: Data on 35 adult liver transplant recipients for model building and 16 patients for model validation were obtained retrospectively. Population average parameter estimates of Cl/F and apparent volume of distribution (V/F) were sought by using the nonlinear mixed-effect model (NONMEM) program. A number of clinical covariates were screened for their influence on these pharmacokinetic parameters. The final optimal population model related Cl/F to total bilirubin, early (< or = 3 days) and late (> 35 days) postoperative days, international normalized ratio (INR), and graft:recipient weight ratio (GRWR). The NONMEM estimates indicated that the Cl/F of tacrolimus was decreased in patients with a small graft, hyperbilirubinemia, and a high INR. In addition, the Cl/F of tacrolimus almost doubled 4 days after transplantation, but decreased with an increase in duration of therapy after day 35. Mean prediction error and mean absolute prediction error were 0.26 and 3.78 ng/ml, respectively, for the validation sample. A final analysis in all 51 patients, which consisted of 1775 blood samples for concentration measurements, identified the following regression model: Cl/F (L/hr) = (0.36 + 2.01/POD * L) * TBIL(-0.23 (TBIL = 1 if TBIL level < or = 1.2 mg/dl, otherwise TBIL = TBIL level)) *49((if POD < or = 3 days)) * 0.75((if INR > 1.4)) * 0.86((if GRWR < or = 1.25%)) * WT, where L was 1 if postoperative day (POD) was greater than 35 days, otherwise L was 0; V/F was 568 L, TBIL was total bilirubin, and WT was body weight. The interindividual variabilities (coefficients of variation) in Cl/F and V/F were 35.35% and 68.12%, respectively. The residual variability was 3.14 ng/ml. CONCLUSION: These findings could be useful to the health care provider for adjustment of tacrolimus dosage in adult liver transplant recipients with various clinical factors.

Adult↗
PubMed2005

Identification of inappropriate drug prescribing by computerized, retrospective DUR screening in Korea.

BACKGROUND: In Korea, the drug use process has changed significantly since the new pharmacy law was implemented in 2000, separating the prescribing and dispensing functions between physicians and pharmacists and mandating prospective drug use review (DUR) practice by pharmacists immediately before dispensing medications. However, a high prevalence of inappropriate prescribing has been suspected by the public, pharmacists, and health insurance managers, possibly due to suboptimal DUR practice by pharmacists. OBJECTIVE: To assess overall patterns of drug usage and potential problems of inappropriate use in outpatient settings by analyzing prescription data that were electronically submitted to the national health insurance manager with a computerized DUR system and develop a computerized adjudication system model for drug claims. METHODS: The national prescription drug claims data that were submitted electronically by pharmacies located in the northern part of Korea during 15 days in 2002 were retrospectively screened against the predetermined DUR standards of the selected criteria on drug dosage, duration of therapy, and drug interaction using the DUR screening system. The results of all the DUR conflicts were further validated manually by an expert panel and statistically analyzed to determine drug use patterns. RESULTS: Of 31,994,260 drugs prescribed, 3,325,760 (10.4%) items showed a conflict with at least one of the DUR standards. The average number of drugs prescribed on each prescription was 4.07, and even more troubling was the high incidence of under-dosing, over-dosing, and contraindicated drug prescribing. CONCLUSIONS: It is evident that inappropriate drug prescribing is very common in Korea; thus, a great deal of attention is urgently needed in the country with respect to proper prescribing and supportive interventions.

Adult↗
PubMed2004

Pharmacokinetic study of mycophenolic acid in Korean kidney transplant patients.

The purpose of this study was to characterize the pharmacokinetic parameters of mycophenolic acid (MPA) in Korean kidney transplant recipients. Plasma MPA concentrations of 10 Korean kidney transplant recipients administered a lower dose of mycophenolate mofetil (MMF; 750 mg twice a day) were measured at 2 weeks of MMF therapy by high-performance liquid chromatography (HPLC). The plasma MPA concentration-time curve pattern of patients taking lower doses of MPA was consistent with previously reported profiles of patients taking the fully recommended doses. The plasma MPA concentration-time curve was characterized by an early sharp peak within 1 hour and a small second peak in some patients at 4 to 12 hours postdose. The mean C(max) and AUC were 8.73 +/- 4.65 microg/mL and 18.45 +/- 4.25 microg*h/mL, respectively. The mean fraction of free MPA was 1.60% +/- 0.23%. Patients' age, weight, body surface area, and renal function did not influence the AUC. The free fraction of MPA appeared not to be affected by serum albumin and renal function when creatinine clearance was above 40 mL/min. Regression analysis between each plasma concentration and AUC for the limited sampling strategy of MMF therapeutic drug monitoring demonstrated that the concentrations of predose and 1- and 8-hour postdose were positively correlated with AUC (r = 0.74545, p = 0.0133; r = 0.68485, p = 0.0289; and r = 0.63636, p = 0.0479, respectively). The pattern of the concentration-time profile of MPA in Korean kidney recipients was similar to the results of other studies performed in Caucasians, although there was interindividual variability of AUC, C(max), and t(max). MPA concentrations of predose and 1- and 8-hour postdose were positively correlated with AUC.

Adult↗
PubMed2003

Comparison of lenograstim and filgrastim on haematological effects after autologous peripheral blood stem cell transplantation with high-dose chemotherapy.

OBJECTIVE: To compare the efficacy of lenograstim and filgrastim on haematological recovery following an autologous peripheral blood stem cell transplantation (PBSCT) with high-dose chemotherapy. METHODS: A retrospective case-controlled study. RESULTS: Absolute neutrophil count (ANC) recovery above 0.5 x 10(9)/l and white blood cell (WBC) recovery above 4 x 10(9)/l for 3 consecutive days was achieved earlier with filgrastim than with lenograstim ((13.2 +/- 8.0 vs 19.0 +/- 10.0 days, p = 0.004), (16.9 +/- 9.7 vs 29.9 +/- 16.6 days, p = 0.001), respectively). The platelet recovery above 20 x 10(9)/l was also achieved earlier with filgrastim than with lenograstim (19.5 +/- 11.6 vs 27.2 +/- 13.8 days, p = 0.006). Furthermore, filgrastim-treated patients received fewer days of granulocyte colony simulating factor (G-CSF) administration (12.5 +/- 7.0 vs 18.6 +/- 8.5 days, p = 0.001) and spent less time in hospital (23.7 +/- 10.9 vs 32.0 +/- 17.6 days, p = 0.009). Duration of antibiotic administration was also significantly shorter in the filgrastim group (13.6 +/- 7.6 vs 29.1 +/- 19.8 days, p = 0.001). CONCLUSION: In patients undergoing PBSCT following high-dose chemotherapy, filgrastim significantly reduced the duration of neutropenia, thrombocytopenia and days of G-CSF administration, and led to earlier hospital discharge compared with lenograstim.

Adjuvants, Immunologic↗
PubMed2002

Long-term lamivudine therapy for chronic hepatitis B in patients with and without cirrhosis.

STUDY OBJECTIVE: To evaluate the effects and safety of 52-week lamivudine therapy in Korean patients with chronic hepatitis B virus (HBV), with and without cirrhosis. DESIGN: Long-term retrospective study. SETTING: Ajoo University Medical Center, Soowon, Korea. PATIENTS: Twenty-seven men and two women who had received oral lamivudine 100 mg/day for 52 weeks for treatment of biopsy-proven chronic HBV; 11 patients had cirrhosis, 18 did not. MEASUREMENTS AND MAIN RESULTS: All 29 patients were positive for HBV DNA and hepatitis B surface antigen (HBsAg) before treatment began; 25 (86%) patients were positive for hepatitis B e antigen (HBeAg). Lamivudine therapy suppressed serum HBV DNA to undetectable levels in 26 (90%) patients within a median of 4 weeks. Serum HBV DNA of 28 patients (97%) fell significantly to undetectable levels within 12 weeks and remained undetectable in 24 (83%) patients after 52 weeks, and HBeAg had converted to negative in 10 (40%) of the 25 patients who were positive. Mean serum alanine aminotransferase (ALT) levels of the 29 patients decreased to within the normal range by 12 weeks and remained at 33-48 IU/L thereafter. Differences in responses of HBV DNA and ALT to lamivudine therapy in HBeAg-positive and -negative patients were negligible (p = 0.786 and p = 0.225, respectively). Pretreatment HBV DNA and ALT levels had no effect on the efficacy of lamivudine (p = 0.9116). Furthermore, differences in responses of HBV DNA (p = 0.641), HBeAg seroconversion (p = 0.386), and ALT (p = 0.689) and in development of drug resistance (p = 0.617) between patients with and without cirrhosis were negligible. No serious adverse effects were reported. CONCLUSION: Lamivudine is an effective and well-tolerated therapeutic agent for treating chronic HBV in patients with and without cirrhosis.

Administration, Oral↗