Doppler ultrasound in the diagnosis of vascular occlusion in renal transplantation

In renal transplantation vascular occlusion is usually diagnosed too late for remedial surgery to be successful. A method of continuous monitoring of renal blood flow would provide evidence of a vascular problem and a chance of saving the graft. In this study directional Doppler ultrasound has been used to investigate arterial stenosis and venous outflow obstruction in a canine autograft model, using the pulsatility index (PI). The results demonstrate increasing PI with venous outflow block (P less than 0.005 at stenoses greater than 88% of venous diameter) and a fall in PI accompanying a progressive reduction in arterial inflow (P less than 0.001 at stenoses greater than 78% of arterial diameter). Identical results were achieved with both handheld and indwelling probes. The changes in the audible Doppler signal have a characteristic quality and the insertion of an indwelling Doppler probe offers a potential means of monitoring allograft blood flow in the immediate postoperative period and differentiating between venous and arterial obstruction.

The effect of surgical operation upon monocytes

The effect of surgical operation upon monocyte numbers and function was studied in patients with both benign and malignant disease. In patients with benign disease a significant increase in the phagocytosis of 99Tc latex-labelled particles by monocytes was observed at 24 h postoperatively (P less than 0.01 compared with preoperatively) and also a significant increase in monocyte numbers (P less than 0.001 compared with preoperatively). In patients undergoing surgery for malignant disease no significant increase in phagocytic activity of monocytes was found postoperatively. A significant decrease in monocyte numbers was shown to follow surgery in this group (P less than 0.001). The implications of these findings are discussed.

Renal transplantation--a tale of two cities

In 1974 three members of the transplant team from the Western Infirmary in Glasgow moved to the new medical school in Leicester. The initial experience with 33 patients transplanted in Glasgow was published in 1972 and this paper compares the results of that series with the first 21 patients grafted in Leicester.

Despite improvements in tissue typing, better quality donor kidneys and fewer complications, there has been a failure to improve on the levels of graft survival. The overall one year graft survival rate in the Glasgow series was 79 per cent compared to 52 per cent in Leicester. In these two series the difference in results appears to be explained by blood transfusion. All the Glasgow patients had been poly-transfused but of the Leicester patients the 10 transfused pre-transplant had a one year graft survival of 90 per cent while in the 11 non-transfused patients the one year graft survival was only 18 per cent.

Effect of silica and carrageenan on the survival of islet allografts

Pancreatic islet cell allotransplantation has considerable potential in the treatment of diabetes mellitus. However, isolated islets appear to be particularly sensitive to rejection and attempts to prolong their survival in experimental animals have so far met with only limited success. In this study the effect of two macrophage suppressing agents, silica and carrageenan, has been investigated in a rat model. Islets from (August x AS) F1 donors were transplanted into AS recipients. Of 13 animals treated with i.v. carrageenan (5 mg/kg), only one had prolongation of graft survival compared to controls. There was indefinite survival in 7 of the 16 animals treated with i.p. silica (50 mg/100 g) and 2 additional animals died normoglycaemic. In an attempt to measure the effectiveness of these two agents in suppressing macrophage activity, the ability of the "fixed" macrophages of the mononuclear phagocytic system to clear particles from the circulation was measured using 125I-labelled microaggregated albumin. Although both carrageenan and silica reduced clearance values, it proved impossible to correlate the degree and duration of this suppression with the success or otherwise of the islet cell allografts.

The effect of levamisole on postoperative immunosuppression

Cell mediated immunity was studied before and after surgery in patients with colorectal cancer. Thymus-derived (T) lymphocytes were enumerated and their non-specific activity was measured by assessing phytohaemagglutinin (PHA)-induced blastogenesis. Specific T lymphocyte activity was measured by leucocyte migration inhibition in response to purified protein derivative of tuberculin (PPD) and autochthonous tumour extract. One group of patients received levamisole postoperatively and the other group consisted of controls. There was a more rapid return to preoperative levels of leucocyte migration inhibition to both antigens by the levamisole group. However, levamisole administration had only a marginal effect on the postoperative depression of cell counts and did not restore depressed lymphoblast transformation.

The reversal of surgically induced reticuloendothelial depression

The function of the reticuloendothelial (RE) system may be depressed by surgical operation. As this system is an important defence mechanism against tumour growth and metastasis, it would be an advantage if this depression could be prevented by the administration of a suitable agent. The agents studied in this case were levamisole, Corynebacterium parvum (C. parvum) and glucan. As a measure of RE function a carbon clearance test was performed in rats, 1 hr after partial colectomy, animals having received pre-operative treatment with one of these substances. The results show that operation produced a significant fall in clearance (P less than 0.001). Both C. parvum and glucan were very effective in preventing any fall of clearance following operation (P less than 0.01). Both of these produced marked RE stimulation and values in animals given these agents remained above control values even after surgery. Levamisole had some effect in preventing the RE depression (P less than 0.02), but was not as effective as either C. parvum or glucan.

Why do protease inhibitors enhance leucocyte migration inhibition to the antigen PPD?

Epsilon amino caproic acid (EACA) and Aprotinin significantly increase the inhibition to PPD in the leucocyte migration test (Burden, Stacey, Wood & Bell, 1978). This is not due to increased leucocyte inhibition factor (LIF) generation. The proteolytic inhibitors prevent the loss of activity of LIF due to prolonged incubation in the presence of serum. Both have a significant effect on the target cells (Polymorphonuclear leucocytes) used in the assay to exaggerate the migration inhibition to LIF. These actions can be explained by decreased proteolytic breakdown of LIF.

The effect of protease inhibitors on leucocyte migration inhibition to tuberculin extract (P.P.D.)

The protease inhibitors, Epsilon Amino Caproic Acid (E.A.C.A.) and Aprotinin were found to significantly increase the inhibition produced by P.P.D. in the Leucocyte Migration Test (L.M.T.). Dose-response curves showed that the most effective concentrations were for E.A.C.A. 0.01 M and Aprotinin 100 I.U./ml. In a series of 29 subjects with a range of Heaf reactivity this finding was consistent providing that there was a significant inhibition to P.P.D. alone. At these concentrations, cell viability was unaffected and the effect of the drugs could be reversed by washing. The exact mode of action of these inhibitors in the L.M.T. requires further elucidation.

The reversal of established enhancement in rat cardiac allografts

Established enhancement in rat cardiac allografts was challenged in a variety of ways in an attempt to provoke rejection. Incompatible skin grafts, injections of sensitised lymphocytes, and the administration of the macrophage-stimulating agent Corynebacterium parvum proved ineffective. However, levamisole, which stimulates both macrophages and sensitised lymphocytes, caused rejection in four of a group of six AS rats bearing enhanced (August X AS)F1 hybrid heart allografts. A combination of C. parvum and levamisole provoked rejection in all four animals in which it was used. The results suggest that an increased activity of both lymphocytes and macrophages is required to break established enhancement.

Is dextran 70 a lymphocyte mitogen?

Dextran 70 ('Lomodex') roduced significant increases in thymidine incorporation in a modified whole-blood method of investigating lymphocyte blastogenesis. This blastogenesis occurred at molar concentrations of 7 X 10(-6) and 7 10(-5). At 7 X 10(-7) mol/l dextran alone did not significantly increase thymidine incorporation; however, when this concentration of dextran was added simultaneously with phytohaemagglutinin there was a significant increase in incorporation. Conversely when dextran was added before P.H.A., thymidine incorporation was decreased. These variable effects indicate that dextran 70 may be a B-cell mitogen. Dextran 70 is widely used and these effects on lymphocyte blastogenesis may be clinically relevant.

Evaluation of rosette inhibition test in renal transplantation

Serial rosette inhibition tests were performed on 11 renal transplant patients in an attempt to predict graft rejection. The rosette inhibition titre was higher in immunosuppressed patients than in normal subjects. The test was of predictive value in only two out of 12 rejection episodes, where a fall in titre to normal levels occurred 48 hours and 24 hours, respectively, before biochemical evidence of rejection. In two further rejection episodes the titre fell at the time of rejection. The titre changes in all tests were small and there were frequent inconsistencies in the results of individual tests. A study of the variables was undertaken, with standardization of the technique, and improvements were made in reading the test. Despite these changes the test was still not sufficiently accurate or reliable to be used as the basis of treatment of rejection episodes.

Renal transplantation: an analysis of 33 cases

Thirty-three patients with end-stage renal failure have had transplants over a three-year period, four patients receiving kidneys from siblings and the remainder cadaver organs. Twenty-seven kidneys survived with stable function for periods of six months to three years. Graft survival at one year was 85% and at two years 82%. One patient died and five were returned to dialysis. Complications included rejection episodes, technical problems, respiratory and wound infections, gastrointestinal disorders, and side effects of steroids.