573 The lows :

labelling procedure we

now use

for urokinase is

as

fol-

,1’Add 5000 Ploug units (albumin free) of urokinase in 2 ml norrnal saline to 2 ml pertechnetate. Add 0.1 ml 0.11 mol/I hydrochloric acid containing 100 fig stannous chloride. Allow to stand for 2 min. ,3:, Pass over ’Dowex 1 x 8’ or suitable exchange resin and collect eluate. ,4) Add phosphate buffer to pH 7.4 and sterilise by filtration. Department of Nuclear Medicine, Rotterdamsch Radio-Therapeutisch Instituut Rotterdam-Zuid, Netherlands

P. H. Cox W. B. VAN DER POMPE G. J. H. DEN OTTOLANDER

SIR,-The negative report by Dr Weir and his colleagues on the usefulness of technetium-99m labelled urokinase for the detection of venous thrombosis is clearly of importance, especially since we continue to obtain good results. 12 Differences in technique must be of great significance, and it is therefore important to identify these. Firstly, Weir et al. adapted a technique based on the method of Kempi et allfor labelling streptokinase using a reaction volume of 6 ml and stannous chloride at a concentration of 70 glm1. We use a reaction volume of 2 ml and a stannous-chloride concentration of 50 g/ml. If we increase the stannouschloride concentration much beyond 50 g/ml the apparent labelling efficiency tends to increase. However, on sterilisation using 0.22 jjun Millipore sterilising filters most of the label is trapped by the filters probably due to significant colloid formation. Unfortunately Weir et al. do not describe their sterilisation technique. Using our own preparation, we always obtain a good hepatic uptake which corresponds with Weir’s observations. There is, however, little or no uptake in the spleen, suggesting that the uptake in the liver is not due to reticuloendothelial activity and consequently that there is little or no colloid in our preparation. It would be interesting to know whether Weir et al. observed any spleen uptake in their studies. If so, this would certainly indicate a colloidal preparation. Secondly, the dose of urokinase used by Weir et al. was 50000 C.T.A. (Committee on Thrombolytic Agents) units, which is substantially greater than the amount we use (7500 C.T.A. units). We get better results if the labelled urokinase is used immediately after preparation because the technetium-99m label is relatively unstable. Weir et al. have not reported any data on the stability of their preparation. We hope that some of these differences in techniques may explain the negative results obtained by Weir et al. West of Scotland Health Boards, Department of Clinical Physics and Bio-Engineering, Glasgow G4 9LF Falkirt and District Royal Infirmary

Thrombosis Research Unit, Department of Surgery, King’s College Hospital Medical London SE5 8RX

School,

V. V. KAKKAR

HLA ANTIGENS IN ULCERATIVE COLITIS

SIR,-We have just completed

our work on histocompatibiin ulcerative colitis in Israel. Our results suggest lity antigens a significant distribution of histocompatibility antigens in ulcerative colitis in Israel. This work, done on 30 Ashkenazi

HLA

FREQUENCIES

(%) IN 30 PATIENTS WITH ULCERATIVE COLITIS AND 100

CONTROLS

W. T. MILLAR J. F. B. SMITH

LOW-DOSE HEPARIN IN TOTAL HIP REPLACEMENT

SIR,-We read with interest the (Aug, 21, p. 423) on our paper.4

treated group, hence the discrepancy in the number of venograms in the two groups. We are surprised at Dr Harris’s remark about the validity of the fibrinogen-uptake test (F.U.T.) in detecting major femoral-vein thrombi; the reference cited3 provides no information on the extent of femoral-vein thrombi missed by the F.U.T., but this information is available in their earlier report6 on 177 patients (including 83 mentioned subsequently3), where the detection of thrombi was by phlebography. 27 femoral-vein thrombi were found in this study, of which only 2 were larger than 5 cm and could be regarded as major thrombi. If these data are correct, then it is likely that only 1 major femoral-vein thrombus (>5 cm) which could have been missed by F.U.T. occurred in the study of 83 patients.’ Such a finding would hardly justify the comment that "fibrinogen scanning will not detect major thrombi in most instances after hip surgery." Furthermore, in our study, in which every patient undergoing total hip replacement underwent both venography and radioactive scanning for the entire duration of their hospital stay, F.U.T. was accurate in detecting the presence or absence of thrombi in 60 (87%) of 69 patients. We believethat the F.U.T. still provides the most dynamic and practical test for the detection of deep-vein thrombosis. Thus, the conclusion drawn from our study,4 that low-dose heparin is effective in preventing the development of life-threatening major thrombi, is entirely valid.

comments

of Dr Harris

In our study both legs, including the thigh of surgery, were scanned in every patient, and venography was done whenever the radioactive counts were raised. There were more patients m the control group who developed raised counts than in the 1. Millar, W. T., Smith, J. F. B. Lancet, 1974, ii, 695. 2. Millar, W. T., Smith, J. F. B. Paper read at the Vth Congress of the International Society on Thrombosis and Hæmostasis, held in Paris, in 1975. 3. Kempi, V., Van der Kinden, W., Von Schéele, C. Br. med. J. 1974, iv, 748. 4. Sagar, S., Nairn, D., Stamatakis, J. D., Maffei, F. H., Higgins, A. F., Thomas, D. P., Kakkar, V. V. Lancet, 1976, i, 1151.

Jews, reveals a significant increase in frequency of HLA-A2, HLA-BW35, and HLA-BW40 and a decrease of HLA-A10. These

findings are different from those given by Asquith et al .66

Laboratory for Tissue Typing, Gastroenterology Unit, Department of Internal Medicine and Department of Surgery Rambam Medical Centre, Technion Aba Khoushy School of Medicine. Haifa, Israel

M. NAHIR O. GIDEONI S. EIDELMAN A. BARZILAI

5. Harris, W. H., and others New Engl. J. Med. 1975, 29, 665. 6. Harris, W. H., Salzman, E. W., Athanasoulis, C., Waltman, A. C., Baum, S., DeSanctis, W. J. Bone Jt Surg. 1974, 56A, 1552. 7. Asquith, P., Mackintosh, P., Stokes, P. L., Holmes, G. K. T., Cooke, W. T. Lancet, 1974, i, 113.

Letter: HLA antigens in ulcerative colitis.

573 The lows : labelling procedure we now use for urokinase is as fol- ,1’Add 5000 Ploug units (albumin free) of urokinase in 2 ml norrnal salin...
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