Biodistribution of technetium-99m pertechnetate after Roux-en-Y gastric bypass (Capella technique) in rats

The biodistribution of sodium pertechnetate, the most used radiopharmaceutical in nuclear medicine, has not been studied in details after bariatric surgery. The objective was to investigate the effect of Roux-en-Y gastric bypass (RYGB) on biodistribution of sodium pertechnetate (Na99mTc-) in organs and tissues of rats. Methods: Twelve rats were randomly divided into two groups of 6 animals each. The RYGB group rats were submitted to the Roux-en-Y gastric bypass and the control group rats were not operated. After 15 days, all rats were injected with 0.1mL of Na99mTc- via orbital plexus with average radioactivity of 0.66 MBq. After 30 minutes, liver, stomach, thyroid, heart, lung, kidney and femur samples were harvested, weighed and percentage of radioactivity per gram (%ATI/g) of each organ was determined by gama counter Wizard Perkin-Elmer. We applied the Student t test for statistical analysis, considering p<0.05 as significant. Results: Significant reduction in mean %ATI/g was observed in the liver, stomach and femur in the RYGB group animals, compared with the control group rats (p<0.05). In other organs no significant difference in %ATI/g was observed between the two groups. Conclusion: This work contributes to the knowledge that the bariatric surgery RYGB modifies the pattern of biodistribution of Na99mTc

Effect of Tripanosomicide Benznidazole (Rochagan®) on the Biodistribution of Sodium Pertechnetate (Na99mTcO4) in Wistar Rats

Benznidazole, a drug with specific anti-Trypanosoma cruzi activity, is used in the treatment of Chagas’ disease. The radiopharmaceutical sodium pertechnetate (Na99mTcO4) is used to obtain diagnostic images of the stomach, thyroid, parathyroids, salivary glands, brain and in the study of esophageal reflux and blood flow. This study aimed at evaluating in vivo the influence of benznidazole treatment on the sodium pertechnetate biodistribution in Wistar rats. The percentage of radioactivity per gram (%ATI/g) of various organs (brain, heart, esophagus, stomach, small intestine, large intestine, spleen, liver, muscle and blood) was determined. Comparing the treated rats with the controls, we observed that sodium pertechnetate biodistribution did not change when administered to rats treated for thirty days with benznidazole

Biodistribution of the Radiopharmaceutical Sodium Pertechnetate after Biliopancreatic Bypass with a Duodenal Switch

Study with the purpose to examine the effects of duodenal switch (DS), regularly performed in morbidly obese patients, on biodistribution of sodium pertechnetate in several organs of rats. There was no early or late mortality in either rats groups. The values of percent radioactivity per gram of tissue (%ATI/g), showed no significant difference in liver, stomach, small bowel, duodenum, kidney, heart, bladder, bone and brain, when compared the DS rats with sham and controls rats. A postoperative significant increase (p<0.05) in mean %ATI/g levels was observed in spleen, pancreas and muscle in group DS rats, as compared to group S and C rats. In the lung there was an increase and in thyroid a decrease in mean %ATI/g of DS rats, when compared to sham rats (p<0.05). In conclusion, the biliopancreatic diversion with duodenal switch in rats modified the biodistribution of sodium pertechnetate in thyroid, lung, pancreas, spleen and muscle

Biodistribution of samarium-153-EDTMP in rats treated with docetaxel

Purpose: Many patients with metastatic bone disease have to use radiopharmaceuticals associated with chemotherapy to relieve bone pain. The aim of this study was to assess the influence of docetaxel on the biodistribution of samarium-153-EDTMP in bones and other organs of rats. Methods: Wistar male rats were randomly allocated into 2 groups of 6 rats each. The DS (docetaxel/samarium) group received docetaxel (15 mg/kg) intraperitoneally in two cycles 11 days apart. The S (samarium/control) group rats were not treated with docetaxel. Nine days after chemotherapy, all the rats were injected with 0.1ml of samarium-153-EDTMP via orbital plexus (25μCi). After 2 hours, the animals were killed and samples of the brain, thyroid, lung, heart, stomach, colon, liver, kidney and both femurs were removed. The percentage radioactivity of each sample (% ATI/g) was determined in an automatic gamma-counter (Wizard-1470, Perkin-Elmer, Finland). Results: On the 9th day after the administration of the 2nd chemotherapy cycle, the rats had a significant weight loss (314.50±22.09g) compared (p<0.5) to pre-treatment weight (353.66± 22.8). The % ATI/g in the samples of rats treated with samarium-153-EDTMP had a significant reduction in the right femur, left femur, kidney, liver and lungs of animals treated with docetaxel, compared to the control rats. Conclusion: The combination of docetaxel and samarium-153-EDTMP was associated with a lower response rate in the biodistribution of the radiopharmaceutical to targeted tissues. Further investigation into the impact of docetaxel on biodistribution of samarium-153-EDTMP would complement the findings of this study

Influence of Splenectomy on the Biodistribution of Technetium-99m Dimercaptosuccinic Acid (99mTc-DMSA) in Rats

This study aimed to evaluate if the splenectomy alters the biodistribution of 99mTc-DMSA and renal function in Wistar rats. The animals were separated in the groups: splenectomy (n = 6) and control (n = 6). After splenectomy (15 days), the administration of 0.1ml of 99mTc-DMSA IV (0.48 MBq) was carried out. Thirty minutes later, kidney, heart, lung, thyroid, stomach, bladder and femur and samples of blood were isolated. The organs were weighed, counted and the percentage of radioactivity -g (%ATI-g) determined. Serum urea and creatinine, hematocrit, leukocytes and platelets were measured. Statistics by t test (p<0.05) was done. There was a significant reduction in %ATI-g in kidney and blood (p<0.05) of splenectomized animals, a significant increase (p<0.05) of urea (88.8 ± 18.6 mg-dL) and creatinine (0.56 ± 0.08 mg-dL), compared to the controls (51.5±1.6, 0.37±0.02mg-dL, respectively), as well as increase in platelets and leucocytes, and hematocrit reduction. The analysis of the results indicates that in rats, splenectomy seems to alter the renal function and the uptake of 99mTc-DMSA

Biodistribution of the Radiopharmaceutical Technetium- 99m-Sodium Phytate in Rats After Splenectomy

Drugs and surgery can interfere with the biodistribution of radiopharmaceuticals and data about the effect of splenectomy on the metabolism of phytate-Tc-99m are scarce. This study aimed at evaluating the interference of splenectomy on phytate-Tc-99m biodistribution and liver function in rats. The SP group rats (n=6) underwent splenectomy. In group C (control) the animals were not operated on. After 15 days, all rats were injected with 0.1mL of Tc-99m-phytate via orbital plexus (0.66MBq). After 30 minutes, liver samples were harvested, weighed and the percentage of radioactivity per gram (%ATI-g) was determined by a Wizard Perkin-Elme gama counter. The ATI%-g in splenectomized rats (0.99±0.02) was significantly higher than in controls (0.4±0.02), (p=0.034). ALT, AST and HDL were significantly lower in SP rats (p= 0.001) and leukocytosis was observed in SP rats. In conclusion, splenectomy in rats changed the hepatic biodistribution of Tc-99m-phytate and liver enzimatic activity

Biodistribution of the radiophamarceutical sodium pertechnetate (Na99mTcO4) after massive small bowel resection in rats

To evaluate the biodistribution of sodium pertecnetate (Na99mTcO4) in organs and tissues, the morphometry of remnant intestinal mucosa and ponderal evolution in rats subjected to massive resection of the small intestine. Methods: Twenty-one Wistar rats were randomly divided into three groups of 7 animals each. The short bowel (SB) group was subjected to massive resection of the small intestine; the control group (C) rats were not operated on, and soft intestinal handling was performed in sham rats. The animals were weighed weekly. On the 30th postoperative day, 0.l mL of Na99mTcO4, with mean activity of 0.66 MBq was injected intravenously into the orbital plexus. After 30 minutes, the rats were killed with an overdose of anesthetic, and fragments of the liver, spleen, pancreas, stomach, duodenum, small intestine, thyroid, lung, heart, kidney, bladder, muscle, femur and brain were harvested. The biopsies were washed with 0.9% NaCl.,The radioactivity was counted using Gama Counter WizardTM 1470, PerkinElmer. The percentage of radioactivity per gram of tissue (%ATI-g) was calculated. Biopsies of the remaining jejunum were analysed by HE staining to obtain mucosal thickness. Analysis of variance (ANOVA) and the Tukey test for multiple comparisons were used, considering p<0.05 as signifi cant. Results: There were no signifi cant differences in %ATI-g of the Na99mTcO4 in the organs of the groups studied (p>0.05). An increase in the weight of the SB rats was observed after the second postoperative week. The jejunal mucosal thickness of the SB rats was signifi cantly greater than that of C and sham rats (p<0.05). Conclusion: In rats with experimentally-produced short bowel syndrome, an adaptive response by the intestinal mucosa reduced weight loss. The biodistribution of Na99mTcO4 was not affected by massive intestinal resection, suggesting that short bowel syndrome is not the cause of misleading interpretation, if an examination using this radiopharmaceutical is indicated

The ileum as a determinant organ of the functional liver cell mass in rats

PURPOSE: To evaluate if the ileum resection changes the functioning liver cell mass, the hepatic metabolism and the biodistribution of radiopharmaceutical in rats. METHODS: Twelve Wistar rats weighing 285g±34g were randomly divided into the ileum resection group (n = 6) and sham group rats (n = 6). After 30 days, they were anesthetized and 0.1mL of 99m-Tc-phytate(0.66MBq) was injected via femoral vein. After 30 minutes, blood samples were collected for red blood cells radioactive labeling and serum ALT, AST and gammaGT. Liver samples were used for 99m-Tc-phytatepercentage of radioactivity/gram of tissue and histopathology. Student’s t test was used with significance 0.05. RESULTS: There was a higher uptake of 99m-Tc-phytate in the liver of sham rats, compared to the ileum resection group (p<0.05). GammaGT, ALT and AST were increased in ileum resection rats compared to sham (p<0.05). The he patocytes count was significantly lower in ileum resection group than in sham (p<0.05). Liver: body mass ratio was lower in experimental animals than in sham group (p<0.05). CONCLUSION: These data support that the ileum has important role in liver function and liver mass regulation, and they have potential clinical implications regarding the pathogenesis of liver injury following lower bowel resection.

Metabolic and hematologic consequences of colectomy associated to hepatectomy in rats

To investigate the influence of partial colectomy associated with hepatectomy on the biodistribution of the 99mTc-phytate, on metabolic parameters, as well as labeling and morphology of red blood cells. METHODS: Wistar rats were distributed into three groups (each with six), nominated as colectomy, colectomy+hepatectomy and sham. In the 30th postoperative day all rats were injected with 99mTc-phytate 0.1mL i.v. (radioactivity 0.66 MBq). After 15 minutes, liver sample was harvested and weighed. Percentage radioactivity per gram of tissue (%ATI/g) was determined using an automatic gammacounter. Serum AST, ALT, alkaline phosphatase and red blood cells labeling were determined. RESULTS: The liver %ATI/g and red blood cells labeling were lower in colectomy and colectomy+hepatectomy rats than in sham rats (p <0.05), and no difference was detected comparing the colectomy and colectomy+hepatectomy groups. Red blood cells morphology did not differ among groups. Serum levels of AST, ALT and alkaline fosfatase were significantly higher in colectomy+hepatectomy than in colectomy rats (p<0.001). CONCLUSION: Hepatectomy associated with colectomy lowered the uptake of radiopharmaceutical in liver and in red blood cells in rats, coinciding with changes in liver enzymatic activity.