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Biomedical subjects

C H Tan

Publications and source records attributed to C H Tan.

At least 145 records · Page 8Linked to original sources
PubMed1981

A direct radioimmunoassay for aldosterone in unextracted serum and plasma.

We describe a novel radioimmunoassay procedure for the direct estimation of aldosterone in unextracted plasma and serum samples, in which interfering binding proteins are digested by Proteinase K (Tritirachium alkaline proteinase, EC 3.4.21.14), a powerful proteolytic enzyme. Heating at 75 degrees C for 15 min inactivates the enzyme before radioimmunoassay. Alternatively, EDTA may be used to inactivate the enzyme. The antibody-bound fraction is then precipitated with polyethylene glycol and isolated by centrifugation. This easy method eliminates extraction and purification and gives accurate and reliable results. The total time required for 100 estimations, including counting time, is about 6 h.

Aldosterone↗
PubMed1980

A longitudinal study of serum iron indices and haemoglobin concentration following copper-IUD insertion.

The increase in menstrual blood loss associated with copper-bearing IUDs may cause or aggravate pre-existing anaemia. In order to evaluate this risk, 84 Malaysian women wearing copper-IUDs were studied longitudinally by means of serial measurements of blood haemoglobin concentration (Hb), serum iron (S/Fe) and transferrin saturation (T/S). The initial Hb was under 12 gm% in 33.7% of patients. The mean Hb showed no significant change up to 12 months while S/Fe fell significantly at the end of this time; the T/S was significantly reduced as early as 6 months post-insertion. There is a significant risk of anaemia following copper-IUD insertion, particularly with long-term usage. Progestogen-releasing IUDs may offer the most feasible solution to this problem in our local context since oral medication with iron or drugs to reduce menstrual blood loss is not practicable.

Adult↗
PubMed1979

Lophozozymus pictor toxin: a potent inhibitor of synaptosomal GABA uptake.

A partially purified toxin obtained from the coral reef crab, Lophozozymus pictor was found to be a potent inhibitor of Na+-dependent [14C]-GABA uptake by rat brain synaptosomes. Inhibition was potentiated in the presence of external K+. The I50 value for the toxin was found to be in the region of 10 microgram/ml at a GABA concentration of 2 microM. The inhibition showed substrate competition.

Animals↗
PubMed1976

Mammalian transcobalamin II metabolism. The immunological and the biological cross-reactivity of mammalain transcobalamin II.

Assay of the reactivity between the chicken anti-rabbit transcobalamin II antiserum and the sera of 19 vertebrate species was carried out by both immuno-diffusion and Sephadex G-200 gel filtration column chromatography. Mammalian transcobalamin II cross-reacted with the antiserum whereas the serum vitamin B-12 binders of the bird, amphibian reptile and fish did not. The biological activity of the purified rabbit transcobalamin II was assessed using reticulocytes or erythrocytes of human, rabbit, guinea pig and rat. The purified rabbit transcobalamin II promoted the uptake of vitamin B-12 by the cells but showed a great variation in its activity. It is suggested that the rabbit transcobalamin II is immunologically and biologically similar to the serum transcobalamin II of the mammalian species studied.

Animals↗