Alternating Use of 123I and 131I Hippuran for Routine Postoperative Monitoring of Transplanted Kidneys is Impracticable

During a 7-week period 123I hippuran was used instead of 131I hippuran for all renographies of transplanted kidneys on Wednesdays. Only in well functioning grafts with a diuresis above 2 ml/min during the examination a scintigraphic improvement of renal and upper urinary visualization was obtained. It is concluded that alternating routine use of the expensive 123I hippuran in control of renal grafts cannot be recommended.

Angiography in Non-Functioning Renal Allografts Receiving Cyclosporin A

During a two-year period angiography was performed in 10 out of 40 initially perfused kidney allografts within the first 3 postoperative weeks. Immunosuppression was in all cases performed with cyclosporin A. The indication for angiography was mainly deterioration in the graft function as judged from the renograms or inadequate demonstration of the graft during intravenous radionuclide angiography. At angiography, neither arterial nor venous occlusion was found, and it was normal in 5 patients. It is concluded that during cyclosporin A treatment angiography cannot be recommended on the above mentioned indications in the early postoperative period. A graft biopsy seems sufficient.

The true clinical significance of renography in nephro-urology

Isotopic renography is a non-invasive technique used routinely by the clinician to provide information about kidney structure and function. Whilst there is no doubt of its value in the accurate measurement of glomerular filtration rate and in the detection of parenchymal abnormalities, its role in the diagnosis of renovascular disease (especially in patients with renal insufficiency), the exclusion of obstruction and the evaluation of the patient with either acute renal failure or renal transplant dysfunction remains unproven. In part, this reflects a failure to standardise protocols and rigorously evaluate diagnostic techniques. Recent developments in ultrasound, computerised X-ray tomography and nuclear magnetic resonance now present the clinician with rival techniques and emphasise the need for the clinical development of isotopic renography.

Radioisotopic evaluation of renal transplants

Owing to the noninvasive nature, ready availability, and efficacy, radionuclide studies remain widely utilized following renal transplantation for monitoring changes in the functional status and detection of detrimental complications of the grafted kidney. Whereas surgical complications, including vascular occlusion, urine extravasation, drainage obstruction, hematoma, or lymphocele formation, can often be detected effectively, specification of other underlying causes of deterioration of parenchymal function, including acute tubular necrosis (ATN), various types of rejection, and cyclosporine A nephrotoxicity (CyA-NT), frequently cannot be derived independently from the findings of a study without clinical correlation. Besides imaging, plotting of renogram or time/activity curves, numerous quantitative methods have been introduced to provide objective measurements of the blood flow, as well as to gauge the capability of concentration and excretion of the transplanted kidneys. However, the findings whether qualitative or quantitative all have overlapping zones. There is no abnormal image, graphic, or numeric index absolutely specific for any of the possible posttransplant renal parenchymal complications. The differentiation of such conditions may best be achieved through chronologic association of the sequential changes, with or without quantification, detected in serial studies with the clinical presentation and findings.

Anisotropy in diffusion-weighted MRI

Diffusional anisotropy of water protons, induced by nonrandom, directional barriers which hinder or retard water motion, is measurable by MRI. Faster water diffusion was observed when the diffusion-sensitizing gradient direction paralleled the long axes of white matter tracts, indicative of fewer barriers to water motion. Diffusion perpendicular to this axis was as much as four times slower. Anisotropy was seen pre- and postmortem in all axial, sagittal, and coronal planes, with and without cardiac gating. Ordering has also been observed in feline optic nerve and in human peripheral nerves. Utilization of this technique can greatly improve understanding and assessment of demyelinating disorders, of white matter infarcts and neoplasms, and of neonatal brain and spinal cord development.

Radionuclide evaluation of renal transplants

In this review article, the following topics are treated: the radiopharmaceuticals 99mTc-diethylenetriaminepentaacetic acid (DTPA), 131I-orthoiodohippurate (OIH), 99mTc-mercaptoacetyltriglycine (MAG3), 67Ga-citrate, radioiodinated fibrinogen, 99mTc-sulfur colloid, 111In-labelled white cells and platelets; gamma camera methods based on images, on first pass and on tubular transit; blood clearance methods; and the diagnosis of surgical complications, acute rejection (AR), acute tubular necrosis (ATN), chronic rejection (CR), and cyclosporine-A (CYA) toxicity.

Adverse reactions and interactions of cyclosporin

Cyclosporin is a potent, widely used specific immunosuppressive agent which affects T-helper cells, and has little myelotoxicity. Its pharmacokinetics are complex and many of its actions remain poorly understood. Numerous side effects have been reported, affecting most organs. Most troublesome have been renal injury, systemic hypertension and vascular changes. Oral use is more effective than intramuscular and safer than the intravenous route. Interactions with other drugs include those which affect hepatic metabolism and those which reduce clearance. Aminoglycosides, macrolide antibiotics, imidazole derivatives, calcium channel blockers, sulphonamides and steroids are included in such interactions. Other metabolic effects of cyclosporin are more subtle and include hyperchloraemic alkalosis, changes in serum potassium and magnesium and effects on testosterone and prolactin levels. Acute poisoning with cyclosporin has been reported, again without myelosuppression. Cyclosporin is an important agent with multisystem toxicity, which requires precise monitoring of drug concentrations, liver and renal function, haemoglobin levels and plasma electrolytes. Cyclosporin pharmacodynamics and interactions with other drugs need to be carefully considered if lower rates of toxicity are to be achieved.

Renography and biopsy-verified acute rejection in renal allotransplanted patients receiving cyclosporin A

Acute impairment of renal function caused by cyclosporin A can be hard to differentiate from acute rejection. Therefore, kidney function after cadaveric allograft transplantation was repeatedly determined by renography in 42 patients receiving either high dose cyclosporin A (32 patients) or azathioprine and prednisone (10 patients) until a graft biopsy showed either acute rejection or no rejection within the first 5 postoperative weeks. The graft function as judged from the renograms was significantly poorer when cyclosporin A was used than when azathioprine and prednisone were the immunosuppressants. In the azathioprine and prednisone group a biopsy showing acute rejection was always preceded by a deterioration in the renogram. In cyclosporin A treated patients a graft biopsy following an early deterioration in the renogram showed acute rejection in only 56% of the biopsies. It was not possible to identify a time course or a function level of the renogram that could predict rejection in these patients. It is concluded that graft biopsies should be used liberally to diagnose rejection during cyclosporin A treatment if surgical complications after transplantation have been ruled out. Radionuclide studies may offer an invaluable aid in determining a nonnephrotoxic initial dose of the drug.