Biomedical subjects

K H Yuen

Publications and source records attributed to K H Yuen.

45 records · Page 3Linked to original sources

PubMed1997

Simple high-performance liquid chromatographic method for the determination of acyclovir in human plasma using fluorescence detection.

A simple high-performance liquid chromatographic method using fluorescence detection was developed for the determination of acyclovir in human plasma. The method entailed direct injection of the plasma sample after deproteination. It is both specific and sensitive with a detection limit of 30 ng/ml at a signal-to-noise ratio of 3:1, and is thus suitable for use in pharmacokinetic studies of acyclovir. The method had a mean absolute recovery of 96%, while the within-day and between-day coefficients of variation and percentages error were all less than 8%. The calibration curve was linear over a concentration range of 62.5-4000 ng/ml.

Acyclovir↗

PubMed1997

A high-performance liquid chromatography analysis of plasma artemisinin using a glassy carbon electrode for reductive electrochemical detection.

A high-performance liquid chromatography assay equipped with a glassy carbon electrode for electrochemical detection (HPLC-ECD) was developed at reductive mode for the analysis of artemisinin, the antimalarial drug from Artemisia annua (Asteraceae) in human plasma. This method was selective, sensitive, and produced satisfactory recovery, precision, and accuracy. Analysis of plasma samples from 8 male volunteers given 10 mg kg-1 of artemisinin orally as an aqueous suspension showed a mean peak plasma concentration (Cmax) of 580.89 ng ml-1 +/- 88.64 SD at 2.5 h +/- 0.5 SD after dosing, and the mean area under the plasma concentration-time curve (AUC0-infinity) was 2227.57 ng h ml-1 +/- 677.22 SD. In addition, the elimination rate constant (Ke), elimination half-life (t1/2), and apparent volume of distribution (Vd) were calculated to be 0.2971 h-1 +/- 0.0644 SD, 2.42 h +/- 0.46 SD, and 16.26 l kg-1 +/- 3.44 SD, respectively.

Adult↗

PubMed1995

The description of the gastrointestinal transit of pellets assessed by gamma scintigraphy using statistical moments.

The gastrointestinal transit of multiple units (e.g., pellets), as determined by gamma scintigraphy, has been characterized by the application of statistical moments. Stomach emptying profiles can be described comprehensively by Mean Gastric Residence Time (MGRT) and Variance of Gastric Residence Time (VGRT) and caecum arrival data by Mean Caecum Arrival Time (MCAT) and Variance of Caecal Arrival Time (VCAT). This maximizes the data available, which is not the case when only described as 50% values. The statistical moments provide different information about the data observed compared to the classical descriptors, as there was only limited correlation between these two sets of parameters. Statistical moments therefore provide an important quantification of the process studied, and they can be used in any statistical test, where it is required to compare different experimental conditions.

Data Collection↗

PubMed1994

Anomalous systemic arterial supply to normal basilar segments of the left lower lobe of the lung: a case report.

We present a patient who had suffered from mild hemoptysis for six years. Abnormal bronchovesicular breath sounds over the left lower lung filed were noted. The chest film also revealed infiltration over the left lower lung field. High-resolution computed tomography (HRCT), aortogram and pulmonary angiography demonstrated anomalous arterial supply to the basilar segments of the left lower lung without coexistence of pulmonary sequestration. Only total nine cases have been reported in English or Chinese literature. The improvement of diagnostic method has enabled an accurate diagnosis before operation with non-invasive examination. Also, this congenital abnormality may not be so rare if meticulously surveyed.

Adult↗

PubMed1993

In vivo/in vitro correlation of experimental sustained-release theophylline formulations.

A novel multiparticulate sustained-release theophylline formulation, which consisted of spherical drug pellets coated with a rate-controlling membrane, was evaluated in vivo. Two preparations that differ solely in the coat thickness, and hence rate of in vitro drug release, were studied in comparison with a solution of the drug. Both preparations produced serum concentration profiles that are reflective of a slow and sustained rate of absorption. The in vivo release versus time profiles calculated using a deconvolution procedure showed that the two preparations differed in the rate but not the extent of drug release. Satisfactory correlation was also obtained between the in vivo and the in vitro results. When the two preparations were further compared using the parameters, time to reach peak concentration (Tp), peak concentration (Cp), and total area under the serum concentration versus time curves (AUC), a statistically significant difference was observed in the Tp and Cp values but not the AUC values, suggesting that the preparations differed in the rate but not the extent of absorption. In addition, the extent of absorption from both preparations was comparable to that obtained with the drug solution.

Absorption↗

PubMed1992

Anomalous systemic arterial supply to normal basilar segments of the lower lobe of the left lung.

A 38-year-old man with an anomalous systemic arterial supply from the descending thoracic aorta to the normal basilar segments of the left lower lobe experienced symptoms of progressive exertional dyspnea. Although the pulmonary parenchyma was normal, there was no pulmonary arterial supply to the basilar segments of the left lower lobe. Left lower lobectomy was performed because of worsening left-to-left shunt. Aortography and pulmonary arteriography form the cornerstone for diagnosis, but a less invasive diagnostic method with less patient suffering is high-resolution computed tomography, which might replace bronchography for accurate evaluation of the distribution and patency of the bronchial tree and delineation of the characteristic "Medusa's hair"-like anomalous vascular supply penetrating into the nearly normal pulmonary parenchyma.

Adult↗

PubMed1992

[Radiology of diffuse panbronchiolitis: experience in VGH-Taipei].

Eleven cases of diffuse panbronchiolitis (DPB) were reported. According to plain chest film (10 cases) and high-resolution computed tomography (HRCT) (11 cases) findings, all were grouped as x-ray type B or CT type II advanced stage. Among them, 4 cases were grouped between CT type II-III; 3, CT type III-IV. All 11 patients had history of chronic paranasal sinusitis (CPS). Three patients had HLA typing. 1 had positive HLA Bw54; 3, HLA Cw1. We suggested patient with CPS, positive HLA Bw54 and Cw1 typing and clinically suspected DPB, radiological study including HRCT should be done.

Adult↗

PubMed1988

Relative bioavailability of the hydrochloride, sulphate and ethyl carbonate salts of quinine.

The hydrochloride, sulphate and ethylcarbonate salts of quinine were given in single oral doses (600 mg base equivalent) to nine healthy male subjects according to a cross-over design. No statistically significant differences were noted in the plasma drug concentration-time profiles although inter- and intra-subject variation in AUC, Cmax and tmax values was appreciable. The ethylcarbonate salt may be preferred for use in paediatric patients because of its neutral taste.

Administration, Oral↗

PubMedDate not supplied

Hong Kong nurses' perceptions of and participation in continuing nursing education.

As medical technologies change, practicing nurses need to update their knowledge and skills to ensure quality health care for patients and to minimize possible health hazards in the workplace. This article describes a study that explored Hong Kong hospital nurses' perceptions of and participation in continuing nursing education. It found that Hong Kong nurses participate actively in continuing education out of a sense of professional responsibility and personal interest. However, consistent with findings from other studies, the major factors hindering nurses' participation are finances, family commitments, and time.

Adult↗