Radioimmunoassay for the measurement of S9788 in serum and microdialysis samples.

S9788, 6-[4-(2,2-di-(fluorophenyl)-ethylaminol-1-piperdinyl]-N,N'-d i-2-propenyl-1, 3,5-triazine- 2, 4-diamine, is a novel compound designed to reverse tumour multidrug resistance associated with cancer chemotherapy. A specific and sensitive radioimmunoassay has been developed for the analysis of S9788 in serum samples and adapted for samples obtained by microdialysis. The limit of quantitation is 0.2 ng ml-1 in perfusion medium and there is no cross reactivity of the antibody with known metabolites of the parent compound or with certain cytotoxic compounds likely to be coadministered with S9788. Maximum probe recovery during microdialysis was 66% at a flow of 1 microliter min-1, using Ringer/BSA (70 mg ml-1) as the perfusion medium. The assay has sufficient sensitivity, precision, accuracy and specificity for the analysis of rat and human serum and microdialysis perfusate samples. The assay has been successfully applied to the determination of S9788 in rat plasma (total concentration) and the microdialysate of the same samples.

The effect of blood transfusion on the incidence of deep vein thrombosis.

The incidence of postoperative deep vein thrombosis in 120 patients undergoing elective total hip replacement was determined venographically. Significantly more blood was administered to those developing thrombosis, particularly in the subgroups given general anaesthesia (P less than 0.05). There were no differences in the postoperative haemoglobin values in any of these groups. The distribution of other risk factors identified, namely previous thrombo-embolism, malignancy and previous vein surgery or injections did not influence this finding. The use of TED stockings (Kendall) was effective. It is suggested that greater emphasis should be placed on techniques that reduce blood loss such as regional anaesthesia and the posterior approach to the hip. Further research into the fluids used for blood volume maintenance will be beneficial.

The detection of deep venous thrombosis by impedance plethysmography in hip surgery patients.

Cuff impedance plethysmography has been performed on 120 patients undergoing total hip replacement surgery, all of whom have had venography. The low incidence of thrombosis (17.5%) precluded any accurate data on sensitivity, but specificity was 85%, positive accuracy 48%, negative accuracy 92% and validity 82%. There was a high false positive rate in the first postoperative week (40% of 25 negative venograms). The technique is of value for the exclusion of thrombi in such patients after the eighth postoperative day. Venography will still be required for the positive identification of thrombi in any research protocol.