Biomedical subjects

X M Chu

Publications and source records attributed to X M Chu.

5 recordsLinked to original sources

PubMed1998

Negative correlation between cyclophilin mRNA level in leukocytes of renal allograft recipients and ciclosporin concentration in whole blood.

AIM: To study mRNA level of cyclophilin in the white blood cells (WBC) of the renal allograft recipients (RAR) and its correlation with ciclosporin concentration in whole blood. METHODS: The cyclophilin mRNA levels and beta-actin as controls in the WBC of 47 RAR were measured by quantitative reverse transcription polymerase chain reaction. The blood ciclosporin assay utilized monoclonal antibody fluorescence polarization immunoassay. RESULTS: With the increase of ciclosporin concentration in whole blood (from 62 micrograms.L-1 to 678 micrograms.L-1), relative cyclophilin mRNA level in the WBC of RAR decreased nonlinearly (from 1.1 to 0.03, r = 0.8195). CONCLUSION: There was a negative correlation between the mRNA level of cyclophilin in the WBC of RAR and the ciclosporin concentration in whole blood.

Adolescent↗

PubMed1996

[Analysis of population pharmacokinetics with NONMEM in clinical patients treated with amikacin by intravenous infusion].

Clinical data (n = 275) collected from 52 patients with respiratory tract infection receiving amikacin (AMK) by intravenous infusion were analysed with NONMEM, a computer program designed for estimating population pharmacokinetic parameters. Concentrations of AMK in serum were determined by fluorescence polarization immunoassay (FPIA). A two compartment open model was used for analysing AMK population pharmacokinetics. The influence of body weight (BW), creatinine clearance (CC), administration history (HIS) and state of pathology (chronic obstructional pulmonary disease, COPD) on pharmacokinetics was investigated. The pharmacokinetic parameters of AMK were shown to be influenced by creatinine clearance (CC) and COPD.

Adult↗

PubMed1995

[NONMEM approach for estimating population pharmacokinetic parameters of phenytoin in Chinese epileptics].

Routine clinical pharmacokinetic data collected from epileptic out-patients who received phenytoin (PHT) were analysed to estimate population pharmacokinetic parameters. There were 258 steady-state serum phenytoin concentrations and associated dosage (mg.d-1) from 161 out-patients. The data were analysed using NONMEM program. The influence of body weight, drug combinations and sex on the maximum elimination rate (Vm) and age on the Michaelis-Menten constant (Km) were investigated. The Vm and Km of phenytoin in a 60 kg adult out-patient, without combination with other drugs (phenobarbital, clonazepam or diazepam) were estimated to be 439 mg.d-1 and 6.21 micrograms.ml-1, respectively. The best function adjusts Vm to the 0.57 power in proportion to body weight. The Km for patients less than 15 years old was 7% less than that for adults. The Vm of patients treated with phenytoin combined with phenobarbital, clonazepam or diazepam will increase 8.4 mg.d-1.

Adolescent↗

PubMed1995

Determination of free digoxin in sera of 8 patients with chronic cardiac insufficiency.

AIM: To establish a method for the determination of free digoxin in serum for clinical use and to study the relationship between the free and total digoxin concentrations in chronic cardiac insufficiency patients receiving digoxin with different renal function. METHODS: The ultrafiltration with fluorescence polarization immunoassay was used to determine the concentration of free digoxin. RESULTS: The concentrations of digoxin standards in serum were 0.96, 1.92, and 3.84 nmol.L-1. The relative standard deviation was < 7% for intra-day and < 6% for inter-day determinations. The average recovery was 99.95 +/- 2.18%. The ratio of free/total digoxin in chronic cardiac insufficiency patients with renal dysfunction was lower than that in patients with normal kidneys (63.5 +/- 4.7% vs 75.1 +/- 3.9%, P < 0.01). CONCLUSION: The present method is simple and reliable. In these patients there is an over-measurement for total digoxin concentration, suggesting the presence of elevated endogenous digoxin-like immunoreactive substances.

Aged↗

PubMed1991

A Bayesian graphic method for predicting individual phenytoin dosage schedule.

A simple and practical graphic method based on Bayesian feedback theory for predicting individual phenytoin dosage was evaluated. Compared with the mathematical calculation, the graphic method only needs one pair of steady-state phenytoin concentration-dose data to predict individual phenytoin dosage. The observed drug levels were compared with predicted ones in 12 epileptic out-patients with a correlation coefficient of 0.94. The mean error between the observed and predicted phenytoin levels was 0.62 mg.L-1. The mean kinetic parameters Vm and Km obtained from the graph were 7.01 +/- SD 0.88 mg.kg-1.d-1 and 4.93 +/- 0.91 mg.L-1, respectively.

Adolescent↗