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Biomedical subjects

C K Cheung

Publications and source records attributed to C K Cheung.

47 records · Page 3Linked to original sources
PubMed1987

Automated trichloroacetic acid precipitation method for urine total protein.

Urine total protein determination by a trichloroacetic acid (TCA) precipitation method was automated on a Cobas Bio centrifugal analyser. The assay measures the turbidity at 420 nm when a 50 microL sample is mixed with 150 microL of 30 g/L TCA at 25 degrees C. Samples up to 5 g/L can be measured by this method and interference due to pigments and turbidity can be minimised by running a blank with 1.25% hydrochloric acid (HC1) instead of TCA. The standard curve is stable and can be stored in the microcomputer and used again. Within-assay precision (CV) varied from 2 to 4.6% and between-assay precision varied from 1.8 to 5.4%. Analytical recovery ranged from 95 to 106.5% and the results correlated well with those obtained by a manual TCA method (r = 0.98). The method is easy to perform and is considerably faster than the manual procedure, thus saving time and providing a faster turnaround time.

Autoanalysis↗
PubMed1986

Automated and routine liquid chromatographic analysis of antiepileptic drugs.

We describe an optimized automated liquid chromatographic method for simultaneous measurement of primidone, phenobarbitone, phenytoin, carbamazepine and clonazepam. A Waters Tri-Module automation system is used and it provides direct read-out of results after chromatography. A one-step extraction with ethyl acetate is used to extract the drugs from 100 microL serum samples. We use an isocratic mobile phase and monitor the column effluent at 210 nm. Drug levels as low as 5 mumol/L can be detected. The within-run CV's range from 1.4 to 2.7%, and the between-run CV's range from 5.2 to 6.1%. Analytical recovery is in the range from 94-108%. The method compares favourably with the enzyme multiple immunoassay technique for routine antiepileptic drugs monitoring, in accuracy, efficiency and cost-effectiveness.

Anticonvulsants↗
PubMed1985

Laser Doppler velocimetry as a monitor of cardiac output changes in dogs.

Cutaneous blood flow may be measured utilizing a continuous, noninvasive technique, laser Doppler velocimetry (LDV). Monitoring of cutaneous blood flow by LDV might be a useful method to monitor cardiac output. To test this hypothesis, sequential measurements of cardiac output, LDV, and transcutaneous oxygen (PtcO2) were made on 10 anesthetized dogs during experimental shock. There was significant correlation between LDV and cardiac output, while PtcO2 reflected cardiac output only at low flow states. These results show that, in the animal model, cutaneous LDV is a sensitive and specific method for monitoring cardiac output changes.

Animals↗
PubMed1984

Hypotensive reaction after infusion of a perfluorochemical emulsion.

A hypotensive episode after rapid administration of a perfluorochemical emulsion, Fluosol-DA (20%), was associated with an immediate decrease in systemic vascular resistance but no significant change in pulmonary vascular resistance. Although the physiologic mechanism for this episode is unclear, the clinical implications are significant: the infusion rate of Fluosol-DA should not exceed 10 ml/min.

Adult↗