Biomedical subjects

P Luenee

Publications and source records attributed to P Luenee.

3 recordsLinked to original sources

PubMed2001

Detection of haemoglobin variants and inference of their functional properties using complete oxygen dissociation curve measurements.

Complete oxygen dissociation curves for red cell suspensions of three haemoglobinopathies, namely haemoglobin (Hb) H, Hb Köln and Hb Tak/beta thalassaemia diseases, were measured using automatic recording methods. These curves were left-shifted compared with the normal red cell curve and showed a biphasic shape as a result of co-existence of the high and normal affinity haemoglobin components. Computer-assisted simulation of these biphasic curves enabled us to infer the curves for the pure abnormal haemoglobins and their fraction in the total haemoglobin of the red cell. The inferred values of fraction agreed with those determined by haemoglobin type analysis or the literature values. The curve for Hb Köln red cells deviated from the normal red cell curve in the whole range of oxygen saturation, whereas the curve for Hb H was close to the normal curve at the middle and upper portions. This difference in deviation was ascribed to a possible interaction between Hb Köln and Hb A through subunit exchange, and its absence between Hb H and Hb A. The present results indicate that measurement of the complete oxygen dissociation curve is important for the detection of non-interacting variants such as Hb H and is useful for inferring the functional properties of haemoglobin components that are not easily isolated.

Chromatography, High Pressure Liquid↗

PubMed1997

Surface and total tissue factor activity of endothelial cells.

With a technic that was developed by us, we found that normal human umbilical vein endothelial cells (HUVEC) in culture characteristically had very little tissue factor (TF) activity either on the surface or in the cells which had been disrupted. In the presence of endotoxin (E. coli O26:B6), a trigger for thrombosis in septicemic patients, we could not detect an increased TF activity of HUVEC on its surface. However, an increase in TF (total TF) was detected after disruption of the cells. The increase in total TF was dose-dependent. Endotoxin at the concentration of 10 micrograms/ml caused around 5 fold increase in total TF activity compared to that of HUVEC in the absence of endotoxin.

Cells, Cultured↗

PubMed1993

Thai national reference preparation in blood coagulation. IV. Home made reference plasma for von Willebrand's factor assay.

Two lots of home made reference plasma: FVIII R:Ag 30/8/88 and FVIII R:Ag 18/10/88 were prepared by lyophilization of pooled normal human plasma. Modification of J. Cejka's technique was used to determine FVIII R:Ag. This technique was tested for reliability i.e. precision, reproducibility and sensitivity. The concentration of FVIII R:Ag, determined by calibration against the 1st British Standard for FVIII R:Ag, human 66/355, which was established by National Institute for Biological Standard and Control (NIBS & C), London, the WHO International Laboratory for Biological Standard, were respectively 1.058 and 1.023 Ag units/ml for FVIII R:Ag 30/8/88 and FVIII R:Ag 18/10/88, respectively. The precision of the procedure and the accuracy of FVIII R:Ag concentration of both lots were verified by using them as standard curve to determine FVIII R:Ag in 4 unknown plasma samples, supplied by the UK Reference Laboratory for Anticoagulant Reagent & Control; WHO Collaborating Center for Quality Assessment, in Blood Coagulation Testing for International Quality Control Survey in Blood Coagulation. The results were very satisfactory. The coefficient of variation was between 2.22-5.47 per cent when compared with other 29 laboratories around the world. These home made reference preparation are stable at least up to 30 months at -70 degrees C, and can be applied for calibration of unknown sample instead of the 1st British Standard for FVIII R:Ag, human 66/355.

Adolescent↗