Renal Accumulation of 99m TC-Dmsa in the Artificially Perfused Isolated Rat Kidney (original) (raw)
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Decreased renal uptake of 99mTc-DMSA in patients with tubular proteinuria
Pediatric Nephrology, 2009
Although technetium-99m-dimercaptosuccinic acid (99m Tc-DMSA) renal scans are widely used to evaluate renal tubular mass function, the mechanism by which renal uptake of DMSA occurs is still the subject of debate. Patients with various proximal tubular disorders show markedly decreased renal DMSA uptake, even when there is normal creatinine clearance. We measured the renal uptake of 99m Tc-DMSA 3 h after its injection in 13 patients with Dent disease or Lowe syndrome, both of which are typical proximal tubular disorders with defective megalin and cubilin-mediated endocytosis. Serial images of three patients were also obtained at 0.5, 1, 2 and 3 h postinjection. The correlations between renal uptake of 99m Tc-DMSA and creatinine clearance and the degrees of acidemia and tubular proteinuria were then evaluated. The renal uptake of 99m Tc-DMSA was markedly decreased in all patients, and the decreased uptake was detected in all serial images. In contrast, bladder radioactivity was higher than normal in all of the serial images when compared to renal radioactivity. Additionally, the uptake of 99m Tc-DMSA was inversely proportional to the amount of urine β 2-microglobulin. These results strongly suggest that DMSA is filtered in the glomeruli and subsequently undergoes megalin-and cubilin-mediated endocytosis in the proximal tubules.
Renal handling of technetium-99m DMSA: evidence for glomerular filtration and peritubular uptake
Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 1989
The finding of an enhanced excretion of [99mTc]dimercaptosuccinic acid (DMSA) in patients with tubular reabsorption disorders prompted us to investigate the role of filtration in the renal handling of [99mTc]DMSA. Our studies in human serum indicated that binding to serum proteins was approximately 90%. Chromatography of human urine and studies in rats showed that the complex was excreted unaltered into the urine. Renal extraction of [99mTc]DMSA in a human volunteer was 5.8%. Continuous infusion of [99mTc]DMSA in 13 individuals with normal renal function gave the following results (mean +/- s.d.): plasma clearance of [99mTc]DMSA 34 +/- 4 ml/min, urinary clearance of [99mTc]DMSA 12 +/- 3 ml/min. The calculated filtered load of [99mTc]DMSA closely resembled the urinary clearance, whereas the plasma clearance was about three times faster. This indicates that peritubular uptake accounts for approximately 65% and filtration for approximately 35% of the renal handling of [99mTc]DMSA.
A kinetic model for99mTc-DMSA in the rat
European Journal of Nuclear Medicine, 1990
A pharmacokinetic model was developed for the renal imaging agent 99~Tc-DMSA in anesthetized rats, which incorporated data from serial measurements of blood and urine simultaneously with dynamic images obtained over an 8-h period. Animals which received a 10 mg/kg dose of unlabeled DMSA immediately before 99mTc-DMSA injection had a significantly reduced kidney accumulation and greater urinary elimination of 99mTc than animals which received the radiopharmaceutical alone. The kidney clearance was also significantly lower in rats receiving unlabeled DMSA, but no significant difference was determined between the urine clearance estimates of the two animal groups. Because the increase in the amount eliminated in the urine was not coupled with a significant change in urine clearance, it would appear that unlabeled DMSA saturated the kidney uptake mechanism(s) of 99mTc-DMSA without modifying the urinary clearance process. This interpretation is consistent with the hypothesis that renal handling of 99mTc-DMSA is governed by both glomerular filtration and peritubular capillary uptake. The simultaneous acquisition of blood, urine and non invasive image data allows for a comprehensive and informative model of the physiological disposition of 99mTc-DMSA.
Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 2000
To determine the function of the remaining contralateral kidney after the removal of a functioning kidney, 30 consecutive patients (18 men, 12 women; average age, 67 y; age range, 34-87 y) who were undergoing unilateral radical nephrectomy were evaluated by sequential quantitative 99mTc-dimercaptosuccinic acid (DMSA) SPECT (QDMSA) studies. The 30 patients were undergoing radical nephrectomy for renal tumors. The first study was done before surgery. Follow-up studies were performed 2-23 mo after surgery. Clinical evaluations and determinations of serum creatinine level were performed at the same time as the QDMSA studies. The relative contribution of the resected kidneys to the global renal function before surgery was 43.2% +/- 7.3%. After surgery the uptake of the remaining kidney increased from 13.4% +/- 4.0% to 18.3% +/- 5.8% (t = 5.7; P = 0.0000). The relative function of the remaining kidney increased from 56.8% +/- 7.1% to 79.1% +/- 23.6% (t = 4.9; P < 0.0001) of the global ...
Journal of Saudi Chemical Society, 2010
Protein binding affects tissue distribution, plasma clearance and uptake of renal radiopharmaceuticals. The 99m Tc bound to plasma protein after incubation 99m Tc-Gluco-ene-diolate (99m Tc-Sn-Gluco) agent or 99m Tc-prylidinomethyl-tetracycline (99m Tc-Sn-PMT) agent with plasma protein. It was observed that the protein bound to 99m Tc is lesser extent with (99m Tc-Sn-Gluco) agent than with the 99m Tc-PMT agent. 99m Tc-Sn-PMT is excreted more rapidly than 99m Tc-Sn-Gluco. On the other hand the percentage binding to protein seems to depend on the origin of the protein and or the type of protein (human or animal). However lower human protein binding or higher protein binding were observed with 99m Tc-Sn-Gluco or with 99m Tc-Sn-PMT, respectively compared with the binding to rat protein. The unbroken down of the chemical form of the origin of these two agents and the highest of 99m Tc-Sn-Gluco remained as origin in urine indicate that 99m Tc-Sn-Gluco are more stable than 99m Tc-Sn-PMT. Concerning the type of protein binding to 99m Tc-Sn-PMT or to 99m Tc-Sn-Gluco, it was observed that Human Plasma Protein is greater binding than Human serum protein or than IgG.
99mTc(Cu)-mannitol complex: a new agent for dynamic renal function studies
International journal of radiation applications and instrumentation. Part B, Nuclear medicine and biology, 1989
Mannitol has been labeled with 99mTc by using cuprous chloride as a reducing agent. Blood and kidney clearance of 99mTc(Cu)-mannitol was slightly faster than that of 99mTc(Sn)-DPTA in rat and maximum radioactivity ratio of kidneys to blood was 84.6 at 5 min. A comparative study of 99mTc(Cu)-mannitol, 99mTc(Sn)-DTPA was made in rabbits by taking serial images of kidneys and bladder with a gamma camera. Results show superiority of 99mTc(Cu)-mannitol over other agents for dynamic renal function studies.
2018
Diethylene triaminopentaacetic acid (99m Tc-DTPA) is one of the technetium radiopharmaceuticals mostly used in renal imaging for evaluation of glomera filtration rate. The 99m Tc-DTPA binding rates on plasma proteins was investigated using two useful and reproducible methods. Equilibrium Dialysis (ED) and Ultrafiltration (UF) are described and there are performances compared. 99m Tc-DTPA binds strongly to Human Serum (HS) than to Human Serum Albumin (HSA). In our assay, using UF technique, we found the binding rates were in HS 48.72 % ±2.58 and 51 % ±1.43 for respectively two 99m Tc-DTPA concentrations [1mg/L] and [2mg/L]. Using ED method we found the binding rates were in HS 11.22 % ±2.17 and 14.94 % ±2.30 for respectively two 99m Tc-DTPA concentrations [1mg/L] and [2mg/L]. Moreover, According to HSA concentrations, the 99m Tc-DTPA binding rates increase using both techniques.
Assessment of the maximum uptake time of 99mTc-DMSA in renal scintigraphy in rat
iranian journal of nuclear medicine, 2017
Introduction:The optimal imaging time of a radionuclide scintigraphy is the time at which the organ of interest has the maximum uptake of the injected radionuclide. This study was performed to investigate the maximum uptake time of 99mTc-DMSA in rat renal scan. Methods: Renal scintigraphy was performed with 3 mCi of 99mTc-DMSA. Planar images were acquired every 20 minutes for 8 hours post-injection using a small-animal SPECT. Results: Activity and the count rate per pixel (CRPP) of the kidneys peaked 1 h post-injection, plateaued for about 1 h, and declined time-dependently. Kidney to background ratio (KBR) reached to 61.7% at 1 h after injection and remained almost constant afterwards. Conclusion: The kidneys had maximum emission and CRPP between 1 to 2 h after 99mTc-DMSA injection, whereas there was no significant difference between the KBRs after 1 h. Our results showed that image acquisition of 1-2 h post-injection is recommended for renal scintigraphy with DMSA in rat.
Molecular and Cellular Biochemistry, 2017
Biochemical and histological assays are currently used for the diagnosis and characterization of kidney injury. The purpose of this study was to compare technetium-99m-labeled dimercaptosuccinic acid (99m Tc-DMSA) renal scintigraphy, as a non-invasive method, with common biochemical and histopathological methods in two animal models of acute kidney injury. Nephrotoxicity was induced either by gentamicin (100 mg/kg/day for one week) or unilateral ureteral ligation (UUO). Renal scintigraphy was performed 1 h after intravenous injection of 99mTc-DMSA (3 mCi). Furthermore, plasma levels of blood urea nitrogen (BUN), creatinine, sodium, and potassium were determined using an autoanalyzer. At the end of experiments, kidneys were excised for the measurement of activity uptake (mCi/gr) using a dose calibrator as well as histopathological examinations with hematoxylin and eosin (H&E) staining. There was a significant decrease in 99mTc-DMSA uptake in both gentamicin (P value = 0.049) and UUO (P value = 0.034) groups, and it was more significant in the former. The levels of BUN and creatinine increased in both gentamicin and UUO groups, while the levels of sodium and potassium remained unchanged. Furthermore, a strong correlation was found between DMSA uptake and histopathological findings. Scintigraphy with 99mTc-DMSA is capable of detection of kidney injury in both gentamicin and UUO groups. Moreover, a significant correlation was found between scintigraphy parameters and histopathological findings. This suggests 99mTc-DMSA as a non-invasive method for the evaluation of kidney injury induced by drugs or anatomical disorders.