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PubMed1980

Comparative examinations of 99mTc-DMS preparations obtained by labelling dimercaptosuccinate kits with different formulations. I. Comparison of chemical and biological characteristics of Tc P-5 and TCK-12 kits.

The chemical and biological properties of two freeze-dried DMS kits for labelling with 99mTc (Tc P-5, manufactured by Boris Kidric Institute, Vinca, and TCK-12, by CIS, Saclay) were compared. A method for the determination of the radiochemical composition of the injection solution is proposed: ascending Whatman 31 paper chromatography in 50% aqueous methanol. The chromatographic results correspond to the biologic activity of the preparations. The biodynamics of both radiopharmaceuticals were determined at intervals in rats. Maximum renal concentrations were achieved at 3-4 hrs post injection (52% kidney and 3% liver uptake for Tc P-5; 59% kidney and 6-8% liver uptake for TCK-12). The bench-lifes of the injection solutions were compared by determining organ distribution after standing of the solutions for 0, 2 and 4 hrs. The Tc P-5 preparation was more stable, since the renal and hepatic concentrations were nearly constant. On the other hand, the hepatic concentration of TCK-12 was increasing during aging of the solution with a simultaneous decrease in renal concentration.

Animals↗
PubMed1980

[Functional imaging of characteristic kinetic parameters of kidney and thyroid (author's transl)].

A procedure has been developed by which the reaction of an organ to a very short delta-function activity pulse of an organ-specific tracer introduced into the blood can be determined for the kidney and the thyroid. The data for the procedure are available from sequence scintigrams and the change with time of the activity of the tracer in the blood. The nature and duration of this reponse function makes it possible to calculate organ-specific parameters such as uptake rates, clearance rates or transit times. They may be calculated for the total field of the gamma camera and delineated as grey or colour gradations to yield the respective parametric functional images. The apparatus necessary for the procedure is described and its possible clinical application in comparison to conventional scintigraphic procedure is discussed.

Humans↗
PubMed1980

Optimal handling of dimercaptosuccinic acid for quantitative renal scanning.

Methods of optimizing quantitative renal imaging with Tc-99m dimercaptosuccinic acid (DSMA) were investigated. Rats were injected with DMSA (one kit per rat) and sacrificed at 0.5, 2.0, and 24 hr after injection. Fifty percent of the injected dose localized in the kidneys at 0.5, 2, and 24 hr after injection while background activity peaked at 0.5 hr and then declined to give substantially higher kidney-to-background ratios at 24 hr. Delayed scanning should increase the accuracy of clinical studies in patients with low kidney-to-background ratios at 1-2 hr. After injection of DMSA, 1 ml of air was introduced into the reaction vials and incubated 20 min. Kidney uptake decreased from 50 to 40% and liver uptake increased from 7.5 to 17%. If multiple doses must be drawn from a single vial, air should not be introduced, and the doses should be drawn together and administered immediately to minimize radiopharmaceutical deterioration.

Animals↗
PubMed1981

Imaging of experimental myocardial infarction with technetium-99m 2,3-dimercaptosuccinic acid.

We have studied the use of Tc-99m-labeled 2,3-dimercaptosuccinic acid (Tc-99m DMSA) to scintigraph acute myocardial infarction after coronary occlusion in dogs. Optimal images were obtained 5 hr after injection of radiotracer, with consistent delineation 48 hr after occlusion. Delivery of tracer was dependent on blood flow. Uptake of tracer correlated to extent of infarction as determined by the myocardial depletion of creatine kinase. Myocardial Tc-99m DMSA was protein-bound.

Animals↗
PubMed1981

Renal functional recovery of the hydronephrotic kidney predicted before relief of the obstruction.

Employing technetium labeled dimercaptosuccinic acid, we predicted the inulin and p-aminohippuric acid (PAH) clearances after recovery of an obstructed kidney before relief of the obstruction. Sixteen rabbits had one renal unit obstructed for varying period of time. The animals were scanned immediately before relief of the obstruction. After 4 to 6 months recovery, inulin and PAH clearances were measured in all animals. The scans were mathematically analyzed, and accurately predicted the inulin and PAH clearances obtained after complete recovery (P less than 0.001 and P less than 0.001, respectively). Six rabbits were scanned at the time of the clearance measurements. By a different mathematical analysis, inulin and PAH clearance measured concurrently correlated with the scan (P less than 0.001 and P less than 0.01 respectively).

Animals↗
PubMed1981

The influence of chelating agents on the distribution and biotransformation of methylmercuric chloride in rats.

Male albino rats were injected i.p. with [203Hg]methylmercuric chloride (MMC) and later at different time intervals they received N-acetylpenicillamine, 2,3-dimercaptopropane-1-sulfonate or dimercaptosuccinic acid (DMSA). The animals were sacrificed 24 h after the last chelant treatment and the content of 203Hg was determined in 10 organs. In liver and kidneys, [203Hg]MMC and 203Hg++ were measured separately. DMSA was most effective in removing the mercurial from all organs, except the kidneys, where 2,3-dimercaptopropane-1-sulfonate was better. N-acetylpenicillamine showed only marginal effectiveness. Separate determinations of [203Hg]MMC and 203Hg++ in liver and kidneys showed that DMSA removed more of the organic and 2,3-dimercaptopropane-1-sulfonate more of the inorganic Hg. DMSA injected i.p. or given p.o. removed almost equal amounts of MMC, indicating virtually 100% absorption of the chelating agent from the gastrointestinal tract.

Animals↗
PubMed1981

Comparative examinations of 99mTc-DMS preparations obtained by labelling dimercaptosuccinate kits with different formulations. II. Comparison of chemical and biological characteristics of TcP-5 and MPI kits.

The chemical and biological characteristics of two dimercaptosuccinate kits were examined and compared: TcP-5 (produced at the Boris Kidric Institute - Vinca) in the freeze-dried form and MPI - the aqueous solution of tin dimercaptosuccinate. The radiochemical composition of the injection solutions was examined by various methods and the method of ascending paper chromatography in 50% aqueous methanol was found as satisfactory. Both preparations has similar compositions. Both preparations showed maximum renal concentrations 3-4 hrs after injection. Liver uptake of MPI was higher than that of TcP-5. The bench-life of both preparations was compared by measuring organ distribution. TcP-5 had a bench-life at least six hrs with a kidney/liver uptake ratio from 5.60 to 8.52, whereas MPI had a satisfactory bench-life of less than half an hour after labelling; thereafter, hepatic concentration rose and the kidney/liver uptake ratio dropped to 1.64.

Animals↗
PubMed1981

Structural requirements for chelate antidotal efficacy in acute antimony(III) intoxication.

The LD50 for i.p. potassium antimonyl tartrate was determined to be 54.6 mg/kg in mice, with a 95% confidence range of 48.4 to 61.7 mg/kg. An examination of the antidotal efficacy of a number of different structural types of chelating agents showed that very few types were able to act as antidotes when potassium antimonyl tartrate was administered i.p. to mice at a level of 120 mg/kg. The most effective antidotes, by a substantial margin, were the water soluble vicinal dithiols: 2,3-dimercaptosuccinic acid and sodium 2.3-dimercaptopropane-1-sulfonate, with the first of these being significantly better than the second. Appreciably less effective, but still useful, was D-penicillamine. At this level of administration of antimony(III), BAL is not an effective antidote. Among other chelating agents which were also not effective at this level of antimony(III) are tartaric acid, EDTA, cysteine, sodium diethyldithiocarbamate and potassium dithiooxalate.

Animals↗
PubMed1981

[Scintigraphy with technetium dimercaptosuccinic acid (99 m TC DMSA). Contribution to the functional assessment of individual kidneys (author's transl)].

Renal uptake of 99m Tc DMSA was used to evaluate the renal function of 16 healthy subjects (controls) and 115 patients with various urinary tract diseases. Scintigraphic examination was carried out 6 hours after an intravenous injection of the product. In the 16 controls Tc DMSA uptake was 25.7 +/- 2.48% in the right kidney and 24.4 +/- 2.86% in the left kidney. In 36 patients with one single hypertrophied kidney, there was a correlation (r = 0.850) between creatinine clearance and Tc DMSA uptake, which was higher than in normal subjects (39.23 +/- 9.9%). In the group of 68 patients with unilateral (31) or bilateral (37) renal disease, a significant correlation (r = 0,725) was observed between kidney-to-kidney ratios of urea clearance and Tc DMSA uptake, so that renal impairment could be quantified. Quantitative scintigraphy did not appear to be of assistance in the remaining 11 patients with obstructive uropathy, as it overestimated renal function. The results obtained with 99 m Tc DMSA scintigraphy should be helpful in choosing between nephrectomy and conservative surgery and in assessing the degree of compensatory hypertrophy in single kidneys.

Creatinine↗
PubMed1980

Effects of obstruction on single-kidney function: clinical and experimental results with 131I-hippurate and 99mTc-DMSA.

In 35 patients, renography with 131I-o-hippurate (OIH) and static renal imaging with 99mTc-dimercaptosuccinic acid (DMSA) were used to measure differential renal function (DRF). The results were compared. Depth correction was applied in both methods. In non-obstructed kidneys (19 patients), both methods revealed nearly identical kidney function (r = 0.98). For completely obstructed kidneys (16 patients), OIH gave a significantly better DRF (14 ml/min) than DMSA. This small difference was of no clinical value. Because DMSA is reported to give unreliable results in unilateral obstructed kidneys, the right ureter was ligated in 8 dogs for 10 days and DRF was measured before and after opening an ureteral fistula. The difference in DRF was about 1% and could be accounted for by the amount of urinary radioactivity collected from the pelvic system after the ligature had been opened. Although DMSA appears to give reliable values in determining DRF, even in obstructed kidneys, OIH is preferred since total clearance values and postrenal urinary dynamics can be determined simultaneously.

Animals↗
PubMed1981

[Value of nuclear medicine and ultrasonography in the management of renal trauma (author's transl)].

Intravenous urography remains the most decisive investigative method in the management of blunt renal trauma. Even minor urographical changes would merit scintiscan and ultrasound examination in order to visualize or rule out parenchymal lesions, intra- or extrarenal hematomas and urine extravasation as well as assess respirational excursions of the kidney. Follow-up studies may be performed without hesitation. Major lesions (primarily a urinoma) and alarming clinical findings necessitate further diagnostic procedures (angiography, possibly after computer tomography). In case of a surgical intervention, angiography cannot be replaced by any other diagnostic method to date. There are no comparative studies of patients with similar injuries managed alternatively with immediate operation or a conservative approach. However, based on our diagnostic possibilities and therapeutical results, we are in favor of a more expectant management of major renal trauma.

Adolescent↗
PubMed1981

Tc-99m DMSA renal uptake: influence of biochemical and physiologic factors.

Thirty-eight female Sprague-Dawley rats were studied to determine the effects of (a) tubular blockade and (b) commonly encountered changes in hydration and acid-base balance, on the urinary excretion and renal localization of Tc-99m dimercaptosuccinic acid (DMSA). Ten additional rats were studied to quantitate the in vivo protein binding of Tc-99m DMSA, and a final group of 12 animals was used to quantitate DMSA distribution in animals with diminished functional renal mass. Both osmotic diuresis and dehydration by water deprivation for 24 hr resulted in a plasma clearance of DMSA slower than in control animals. Acid-base imbalances significantly affected the renal accumulation of DMSA, and acidosis was associated with markedly increased background due to increased liver accumulation. The protein-bound portion of Tc-99m DMSA in the plasma was high, reaching 89% within the first 5 min, and rising very slightly (n.s.) ith time. The unbound portion of DMSA had a plasma clearance slightly higher than the GFR. Ablation of large amounts of renal tissue, resulting in significant decreases in GFR. Ablation of large amounts of renal tissue, resulting in significant decreases in GFR, did not significantly affect the renal localization of DMSA in the intact portions of the kidneys. These data demonstrate that commonly encountered changes in acid-base balance and hydration will significantly alter the biologic distribution of Tc-99m DMSA. These factors should be controlled when carrying out clinical studies.

Acid-Base Imbalance↗