Irami Araújo-Filho

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

PURPOSE To evaluate the biodistribution of sodium pertecnetate (Na(99m)TcO(4)) 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 Na(99m)TcO(4), 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 Wizard 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 significant. RESULTS There were no significant differences in %ATI/g of the Na(99m)TcO(4) 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 significantly 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 Na(99m)TcO(4) 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.

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.

Efeito da sinvastatina na sepse abdominal de ratos diabéticos

OBJECTIVE: Infection and sepsis are major causes of morbidity and mortality after surgery of diabetic patients. Statins have been shown to exhibit anti-inflammatory and immunomodulatory (pleiotropic) effects, independent of lipid lowering. This study aimed to observe whether the pretreatment with simvastatin in a cecal ligation and perforation model of sepsis is beneficial in diabetic rats. METHODS: Fifty six Wistar rats were randomly assigned to non-diabetic group (n=28), and streptozotocin-induced diabetic group (n=28). Abdominal sepsis was induced in 14 diabetic and in 14 non diabetic rats and the other 28 rats were allocated on sham group. Sepsis rats and sham rats (each with 7 animals) were treated with oral simvastatin (20 mg kg-1 day-1) or normal saline solution 0.9%. Peripheral blood TNFα, IL-1β, IL-6, C-reactive protein, procalcitonin, leukocytes and neutrophils were tested in all the animals. Statistical analysis was done by ANOVA and Tukey test, with p<0.05. RESULTS: Simvastatin reduced mortality in diabetic rats. Peripheral blood TNFα, IL-1β, IL-6, C-reactive protein, procalcitonin, leukocytes and neutrophils were lower in diabetic and non diabetics septic rats treated with simvastatin, than after saline treatment. CONCLUSION: Simvastatin showed anti-inflammatory effect, which could play some protection against the progress of sepsis in diabetic rats.

Nanotechnology in Phytotherapy: Antiinflammatory Effect of a Nanostructured Thymol Gel from Lippia sidoides in Acute Periodontitis in Rats

Lippia sidoides Cham (Verbenaceae) is largely distributed in the northeastern region of Brazil. It is popularly known as ‘Alecrim‐pimenta’. Recent studies have shown that some species of Lippia have interesting pharmacological activities. This study aimed to evaluate the effect of a nanostructured thymol gel (TG) 1.2 mg/g on acute phase of ligature‐induced periodontitis model [acute periodontal disease (APD)] in rats. APD was induced in 24 Wistar rats subjected to ligature placement on left molars in maxillae. Animals were treated with TG, immediately after APD induction. Saline‐based gel was utilized as negative control and diethylammonium diclofenac gel 10 mg/g was used as positive control. Animals were randomly assigned into the groups. The periodontium and the surrounding gingiva were examined at histopathology, as well as the neutrophil influx into the gingiva was assayed using myeloperoxidase activity levels by ELISA method. TG treatment reduced tissue lesion at histopathology coupled to decreased myeloperoxidase activity production in gingival tissue when compared with the saline gel control group (p < 0.05). The TG gel was able to provide a significant myeloperoxidase decreasing in gingiva tissue confirming to be effective in reducing gingival inflammation in this model. Copyright

how can micelle systems be rebuilt by a heating process

The aim of this work was to evaluate how an aqueous micellar system containing Amphotericin B (AmB) and sodium deoxycholate (DOC) can be rebuilt after heating treatment. Also, a review of the literature on the physicochemical and biological properties of this new system was conducted. Heated (AmB-DOC-H) and unheated (AmB-DOC) micelles were then diluted at four different concentrations (50 mg · L−1, 5 mg · L−1, 0.5 mg · L−1, and 0.05 mg · L−1) to perform physicochemical studies and a pharmacotoxicity assay, in which two cell models were used for the in vitro experiments: red blood cells (RBC) from human donors and Candida parapsilosis (Cp). While potassium (K+) and hemoglobin leakage from RBC were the parameters used to evaluate acute and chronic toxicity, respectively, the efficacy of AmB-DOC and AmB-DOC-H were assessed by K+ leakage and cell survival rate from Cp. The spectral study revealed a slight change in the AmB-DOC aggregate peak from 327 nm to 323 nm, which is the peak for AmB-DOC-H. Although AmB-DOC and AmB-DOC-H exhibited different behavior for hemoglobin leakage, AmB-DOC produced higher leakage than AmB-DOC-H at high concentrations (from 5 mg · L−1). For K+ leakage, both AmB-DOC and AmB-DOC-H showed a similar profile for both cell models, RBC and Cp (P < 0.05). AmB-DOC-H and AmB-DOC also revealed a similar profile of activity against Cp with an equivalent survival rate. In short, AmB-DOC-H showed much less toxicity than AmB-DOC, but remained as active as AmB-DOC against fungal cells. The results highlight the importance of this new procedure as a simple, inexpensive, and safe way to produce a new kind of micelle system for the treatment of systemic fungal infections.

Metabolism and gastric remnant changes after Roux-en-Y gastric bypass in rats.

ABSTRACT Background: The Roux-en-Y gastric bypass (RYGB) may affect metabolism, microbiology, and histology of gastric remnant. Therefore, this study aimed to investigate these issues in rats. Methods: Twelve rats were randomly allocated to a RYGB group (n = 6) and nonoperated normal rats group (n = 6). After 30 postoperative days, all rats were injected with 0.1ml of Na99mTc− i.v. (radioactivity 0.66 MBq). After 30 min, liver, stomach, thyroid, heart, lung, kidney, and femur samples were harvested and weighed. Percentage radioactivity per gram of organ (%ATI/g) was determined using a Perkin-Elmer gamma counter. Serum albumin, calcium, aminotransferases (ALT, AST), T3, T4, and PTH were determined. Samples of the excluded stomach mucosa were harvested for bacterial and fungal count such as colony-forming units/g and histology. Results: A significant reduction (t test) in %ATI/g was observed in the liver, stomach, and femur in the RYGB rats, compared with normal rats (p < .05). A significant reduction in serum albumin and calcium in RYGB rats was detected, compared with normal rats (p < .05). ALT and AST were significantly different between the two groups. T3 and T4 levels were significantly lower in RYGB rats than in normal rats (p < .05); PTH levels were higher in RYGB rats than in controls (p = .009). The gastric remnant mucosa of RYGB rats showed higher bacterial and fungal count, atrophy, intestinal metaplasia, and neutrophilic polymorphonuclear inflammation than in normal rats. Conclusions: This investigation demonstrated that a model of murine RYGB significantly modified metabolic parameters and the microbiology/histology of the remnant stomach.

Biodistribution of technetium-99m pertechnetate after total colectomy in rats

This study evaluated the effects of total colectomy on the biodistribution of technetium-99m pertechnetate ((99m)TcO(4)(-)) on the 28th postoperative day in rats. Samples of several organs were harvested for counting the percent of injected radioactivity/g of tissue (%ATI/g). The %ATI/g in colectomy rats was higher in the stomach and ileum than in sham and controls (p<0.05). Increase in mucosa and muscularis size of ileum was observed. Colectomy was associated with lower biodistribution in bladder and thyroid, T3, and T4, than in controls.

Prevention of bacterial translocation using beta-(1-3)-D-glucan in small bowel ischemia and reperfusion in rats

PURPOSE To investigate the role of beta-(1-3)-D-glucan on 99mTc labelled Escherichia coli translocation and cytokines secretion in rats submitted to small bowel ischemia/reperfusion injury. METHODS Five groups (n=10 each) of Wistar rats were subjected to control(C), sham(S), group IR subjected to 45 min of bowel ischemia/60 min of reperfusion(I/R), and group I/R+glucan subjected to 45 min of bowel ischemia/60 min of reperfusion(I/R) and injected with 2 mg/Kg intramuscular. Translocation of labelled bacteria to mesenteric lymph nodes, liver, spleen, lung and serum was determined using radioactivity/count and colony forming units/g(CFU/g). Serum TNFalpha, IL-1beta, IL-6, IL-10 were measured by ELISA. RESULTS CFU/g and radioactivity/count were higher in I/R than in I/R+glucan rats. In C, S and S+glucan groups, bacteria and radioactivity/count were rarely detected. The I/R+glucan rats had enhancement of IL-10 and suppressed production of serum TNFalpha, IL-1beta and, IL-6, compared to I/R untreated animals. CONCLUSION The beta-(1-3)-D-glucan modulated the production of pro-inflammatory and anti-inflammatory cytokines during bowel ischemia/reperfusion, and attenuated translocation of labelled bacteria.

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

PURPOSE 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 (Na(99m)Tc(-)) 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 0.1 mL of Na(99m)Tc(-) 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 Na(99m)Tc(-).

Metabolic and hematologic consequences of colectomy associated to hepatectomy in rats

PURPOSE To investigate the influence of partial colectomy associated with hepatectomy on the biodistribution of the (99m)Tc-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 30(th) postoperative day all rats were injected with (99m)Tc-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 gamma-counter. 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.