technetium-tc-99m-sulfur-colloid and Disease-Models--Animal

Sentinel lymph node biopsy (SLNB) has been utilized for cutaneous melanoma and other malignancies arising from the eye and ocular adnexa. Currently, SLNB requires blue dyes and/or radiopharmaceuticals; both of which have significant shortcomings. This study sought to evaluate the feasibility of SLNB with the use of real-time, contrast-enhanced ultrasound (CEUS) as an alternative technique for tumors arising in the conjunctiva.. Prospective feasibility study in a porcine model.. Twelve experiments were performed on six non-tumor-bearing Yorkshire swine. An ultrasound contrast agent, Sonazoid (GE Healthcare, Oslo, Norway), (99m) technetium ((99m) Tc), and methylene blue (MB) (Covidien, Mansfield, MA) were injected in the ocular conjunctiva. Sentinel lymph nodes (SLNs) were localized with CEUS and findings were compared to that of MB and (99m) Tc. Fisher exact test was used.. Contrast-enhanced SLNs were identified within an average of 6.2 minutes from time of injection of Sonazoid. A total of 17 SLNs were identified by at least one of the three techniques. Correlation between Sonazoid and (99m) Tc was 94.1% (16/17 SLNs). Correlation between (99m) Tc and MB was 88.2% (15/17). One SLN that was positive for (99m) Tc but negative for Sonazoid and was considered to be a false positive (1/17); findings were similar for MB (1/17). Differences between the three techniques were not significant (P = .886).. CEUS-guided injection of conjunctiva for SLNB is technically feasible and correlates well with standard detection techniques. This technique shows promise for rapid, real-time, intraoperative imaging for SLNB, using a widely available imaging modality and avoiding the need for radiopharmaceuticals.. NA

Topics: Animals; Conjunctiva; Conjunctival Neoplasms; Contrast Media; Disease Models, Animal; Endoscopic Ultrasound-Guided Fine Needle Aspiration; Feasibility Studies; Ferric Compounds; Injections, Intraocular; Iron; Melanoma; Oxides; Random Allocation; Rosaniline Dyes; Sensitivity and Specificity; Sentinel Lymph Node Biopsy; Swine; Technetium Tc 99m Sulfur Colloid

To use (99m)Tc sulfur colloid ((99m)Tc-SC) and (99m)Tc mebrofenin ((99m)Tc-BrIDA) to study liver function in normal and diabetic rats.. Radionuclide imaging was performed on 2 groups of rats, using (99m)Tc-SC for one group and (99m)Tc-BrIDA for the other (20 rats per group) before and after induction of diabetes mellitus (DM) using streptozotocin administration (55 mg/kg i.p.). Dynamic acquisition was obtained for 1 h after the injection of 37 MBq of radiotracer. For the (99m)Tc-SC group, organ/tissue uptake was determined by drawing regions of interest (ROI) over the heart, liver, spleen and also the whole body (WB). The ratio of the ROI of each organ to the WB ROI was calculated. For (99m)Tc-BrIDA, ratios of cumulative count rates in liver, liver parenchyma, biliary tree and abdomen ROI to a WB ROI were also calculated. Statistical analysis was performed to compare the ratios of organ/tissue uptake to WB uptake before and after DM induction using the paired t test.. (99m)Tc-SC uptake ratios (means ±SD) showed a lower liver-to-WB uptake ratio (0.75 ± 0.05) in the rats after DM induction compared to baseline (0.81 ± 0.06), while the cardiac blood pool showed higher uptake ratios in the rats after DM induction (p = 0.026). For (99m)Tc-BrIDA, there was no significant difference in radiotracer uptake ratios obtained from the rats before and after DM induction (p = 0.41).. Using functional liver imaging, there was a statistically significant decrease in the liver phagocytic/reticuloendothelial system function after DM induction, as evidenced by decreased (99m)Tc-SC liver uptake and increased blood pool compared to prediabetes, while the hepatobiliary function remained unchanged after DM induction using (99m)Tc-BrIDA imaging.

Topics: Aniline Compounds; Animals; Diabetes Mellitus, Experimental; Disease Models, Animal; Glycine; Imino Acids; Liver; Liver Function Tests; Male; Organotechnetium Compounds; Phagocytosis; Radionuclide Imaging; Radiopharmaceuticals; Rats; Rats, Sprague-Dawley; Statistics as Topic; Technetium Tc 99m Sulfur Colloid; Time Factors

The purpose of this study was to compare lymphosonography (ie, contrast-enhanced ultrasound imaging [US] after interstitial injection of a US contrast agent) for the detection of sentinel lymph nodes (SLNs) in swine with naturally occurring melanoma tumors to lymphoscintigraphy using blue dye-guided surgical dissection as the reference standard. Also, we sought to determine if lymphosonography can be used to characterize SLNs.. Sixty-three swine with 104 melanomas were evaluated. Contrast-specific US was performed after peritumoral injection (1 mL dose) of Sonazoid (GE Healthcare, Oslo, Norway). Lymphoscintigraphy was performed after peritumoral injections of technetium Tc 99m sulfur colloid. Peritumoral injection of 1% Lymphazurin (Ben Venue Labs, Inc, Bedford, OH) was used to guide SLN resection. The accuracy of SLN detection with the two imaging modalities was compared using the McNemar test. The SLNs were qualitatively and quantitatively characterized as benign or malignant based on the lymphosonography results with histopathology and RNA analyses used as the reference standards.. Blue dye-guided surgery identified 351 SLNs. Lymphosonography detected 293 SLNs and 11 false-positives, while lymphoscintigraphy detected 231 SLNs and 20 false-positives. The accuracy of SLN detection was 81.8% for lymphosonography, which was significantly higher than the 63.2% achieved with lymphoscintigraphy (P < .0001). The accuracy of lymphosonography for SLN characterization was 80%. When the size of the enhanced SLN was taken into consideration to characterize SLNs, the accuracy was 86%.. Lymphosonography is statistically better than lymphoscintigraphy for the detection of SLNs in this animal model. The ability to use lymphosonography as a means to characterize SLNs as benign or malignant is limited.

Topics: Animals; Chi-Square Distribution; Coloring Agents; Contrast Media; Disease Models, Animal; Ferric Compounds; Imaging, Three-Dimensional; Iron; Lymph Nodes; Lymphatic Metastasis; Melanoma; Oxides; Predictive Value of Tests; Radionuclide Imaging; Radiopharmaceuticals; Rosaniline Dyes; Sensitivity and Specificity; Sentinel Lymph Node Biopsy; Statistics, Nonparametric; Swine; Technetium Tc 99m Sulfur Colloid; Ultrasonography; Videotape Recording

This paper discusses the influence of a para-areolar incision in the upper outer quadrant of the breast on the location of the sentinel lymph node in a canine model.. The sentinel lymph node was marked with technetium-99, which was injected into the subareolar skin of the cranial breast. After the marker had migrated to the axilla, an arcuate para-areolar incision was performed 2 cm from the nipple in the upper outer quadrant. Patent blue dye was then injected above the upper border of the incision. At the marked site, an axillary incision was made, and the sentinel lymph node was identified by gamma probe and/or by direct visualization of the dye. The agreement between the two injection sites and the two sentinel lymph node identification methods was determined. Our sample group consisted of 40 cranial breasts of 23 adult females of the species Canis familiaris. The data were analyzed by using the McNemar test and by determining the kappa agreement coefficient.. Our findings showed that in 95% of the breasts, the sentinel lymph node was identified by the injection of technetium-99 m into the subareolar region, and in 82% of the cases, the sentinel lymph node was identified by the injection of patent blue dye above the upper border of the incision. The methods agreed 82% of the time.. Previous para-areolar incisions in the upper outer quadrant did not interfere significantly with the biopsy when the dye was injected above the upper border of the incision.

Topics: Animals; Disease Models, Animal; Dogs; Female; Mammary Neoplasms, Animal; Nipples; Radionuclide Imaging; Radiopharmaceuticals; Sentinel Lymph Node Biopsy; Technetium Tc 99m Sulfur Colloid

To compare the thrombolytic effects of the two dosing regimes with urokinase (UK) in a canine model of pulmonary thromboembolism induced by radioactive blood clots.. Seventeen dogs were randomly assigned into three groups: the control group, the UK(2h) group (UK infused over 2 hours) and the UK(12h) group (UK given over 12 hours). The thrombolytic differences was investigated among the three groups. Thrombolysis was assessed by continuously counting over both lung fields with single photon emission computed tomography (SPECT) and calculated by regions of interest (ROI) technology and by counting radioactivity in the lung in vitro. The extent of thrombolysis was calculated as the difference between the radioactivity originally incorporated in the clot (decay-corrected) and the radioactivity in the lung in vitro.. In three groups, the lysis rates measured by ROI technology were (6.2 +/- 4.0)%, (39.5 +/- 13.9)%, and (16.9 +/- 8.9)% respectively, and (6.0 +/- 2.7)%, (42.8 +/- 12.4)%, and (17.7 +/- 9.3)% by the method in vivo. The thrombolytic ratio of the UK(2h) group was significantly higher than that of the other two groups (P < 0.01), and there was no marked difference between the control group and the UK(12h) group. There was a thrombolytic peak in the UK(2h) group at the first four hours after infusion of agent.. For the fresh thrombi, the UK(2h) regime is superior to the UK(12h) due to its higher thrombolytic ratio and prompt thrombolytic property. The model and methods are highly reliable.

Topics: Animals; Disease Models, Animal; Dogs; Female; Male; Pulmonary Embolism; Technetium Tc 99m Sulfur Colloid; Thrombolytic Therapy; Urokinase-Type Plasminogen Activator

To establish a canine model of pulmonary thromboembolism (PTE) for evaluating the effects of thrombolytic therapy.. The preparations of radioactive blood clots in vitro were made from fresh whole blood (from 6 donors) mixed with (99m)Tc-SC. After eluting the clots with saline solution, the stability and evenness of (99m)Tc-SC in the clots were determined. Then a canine model of PTE induced by these clots was established and the rates of spontaneous lysis were measured by the regions of interest (ROI) technique and the in vitro method.. (99m)Tc-SC was stable in the radioactive blood clots after elution, and the radioactivities in the thrombi were well-distributed. The rates of thrombolysis were (6.2 +/- 4.0)% as measured by ROI and (6.0 +/- 2.7)% by the in vitro method.. (99m)Tc-SC is stable and well-distributed in blood clots. A canine model of PTE can be induced by autologous radioactive blood clots.

Topics: Animals; Disease Models, Animal; Dogs; Evaluation Studies as Topic; Female; Humans; Male; Pulmonary Embolism; Radionuclide Imaging; Technetium Tc 99m Sulfur Colloid; Thrombolytic Therapy; Urokinase-Type Plasminogen Activator

In regard to nuclear medicine literature reporting lung uptake of colloidal radiopharmaceuticals in patients with liver diseases, it has been hypothesized that liver abnormalities could trigger induction of pulmonary intravascular macrophages (PIMs) in humans normally lacking them. Recently, experimental induction of PIMs in rats in which they are not normally prevalent has been demonstrated to be at the origin of pulmonary hemodynamic alterations with an increased susceptibility to ARDS. If such induction may occur in humans, the risk of pulmonary hemodynamic alterations has to be considered and detected. This study demonstrates in a rodent model of biliary cirrhosis that scintigraphy of phagocytic function as commonly used for liver exploration is a suitable strategy for staging PIM development.. Sixty rats were randomized as follows: bile duct section (n = 40), sham operation (n = 10), and no operation (n = 10). The rats were submitted to scintigraphy of phagocytic function every 5 days over 35 days for the assessment of radiocolloid uptake within lung and liver. At day 35, radioactivity of blood was counted and immunohistochemistry was performed on lung specimens.. As disease progressed, radiopharmaceutical uptake decreased within the liver, while increasing considerably in the lung. At day 35, lung uptake averaged about 66% as compared to 3% before surgery. Lung histologic findings revealed numerous intravascular mononuclear cells closely related to the monocyte-macrophage lineage.. Scintigraphy of phagocytic function commonly used for liver scanning could be a suitable strategy for the diagnosis of the induction of PIMs under pathologic situations.

Topics: Animals; Disease Models, Animal; Disease Progression; Immunohistochemistry; Liver; Liver Cirrhosis, Biliary; Lung; Macrophages, Alveolar; Male; Phagocytosis; Radionuclide Imaging; Radiopharmaceuticals; Random Allocation; Rats; Rats, Wistar; Technetium Tc 99m Sulfur Colloid

ABSTRACT. The aim of the present study was to investigate the lymphatic cardiac circulation in an experimental model of ischemia plus reperfusion in mongrel dogs (Canis familiaris L). As radiotracer we used 0.2-0.25 ml (111 MBq) of 99mTc-Re2S7 colloid (+/-10 microm), injected subcapsullary below the second diagonal of the descending anterior ligated coronary artery with a special needle. A gamma-camera/Starport + DecStation were used for data acquisition. Four experimental groups with five animals each were established: G I = controls; G II = immediately after acute myocardial infarction (AMI); G III = late infarction (5 days after AMI); G IV = ischemia (90 min) + reperfusion. Four regions of interest (ROIs) were chosen: injection area (ZA), above (ZB), near right (ZD), and far right (ZC) from ZA. Mean disappearance times in ZA and dynamic parameters in the other ROIs were determined from activity/time curves drawn in each area, using homemade software. The results obtained seem to indicate that the methodology is appropriate to a detailed study of lymphatic drainage in pathological situations in animal models.

Topics: Animals; Colloids; Disease Models, Animal; Dogs; Female; Heart; Lymphatic System; Male; Myocardial Ischemia; Myocardial Reperfusion; Radioactive Tracers; Radionuclide Imaging; Reperfusion Injury; Rhenium; Technetium Tc 99m Sulfur Colloid; Time Factors

The dose-dependent effects of tissue-type plasminogen activator (t-PA) on the kinetics of cerebral clot lysis in a rabbit model of middle cerebral artery embolic stroke were investigated. The clots were formed in vitro and tagged with 99Tc for gamma-scintigraphic imaging. After embolization, groups of animals were treated with t-PA. Dose-response curves for the t-PA were generated, and in addition, long and short dosing schedules were assessed. The optimal doses for frequency and rate of cerebral clot lysis in this model are approximately 6.3 mg/kg given over 2 hr or 3.3 mg/kg given over 30 min. These dosing regimens for t-PA were accompanied by approximately 50% consumption of plasma plasminogen, fibrinogen and alpha 2-antiplasmin. Doses of t-PA on either side of this optimum caused attenuation in both the frequency and rate of cerebral clot lysis. Treatment with t-PA under either dosing regimen did not augment the frequency of hemorrhagic transformation, but the size of the resultant hemorrhage in those animals where intracranial bleeding occurred was reduced by 3.3 mg/kg t-PA given over 30 min.

Topics: Animals; Cerebral Arteries; Cerebral Hemorrhage; Disease Models, Animal; Dose-Response Relationship, Drug; Enzyme-Linked Immunosorbent Assay; Intracranial Embolism and Thrombosis; Male; Rabbits; Technetium Tc 99m Sulfur Colloid; Thrombolytic Therapy; Tissue Plasminogen Activator

We employed a canine model of coronary thrombosis, induced by injection of radioactive blood clot, via a catheter placed in the left anterior descending coronary artery, to compare effects of intracoronary administration of recombinant tissue plasminogen activator (rtPA) and urokinase (UK) on rate and extent of coronary thrombolysis. Two doses of UK, 15,000 U/kg (UK15) and 30,000 U/kg (UK30) and two doses of rtPA, 0.25 mg/kg (rtPA.25) and 0.75 mg/kg (rtPA.75) were given. Drugs were infused over 45 min. Compared with the other regimens, rate and extent of coronary thrombolysis were significantly increased with rtPA.75. Also, despite a much higher dose of UK, coronary thrombolysis was similar with UK30 and rtPA.25. Compared with UK15, rate and extent of coronary thrombolysis were increased with rtPA.25. These results indicate that intracoronary administration of rtPA is superior to intracoronary UK in inducing thrombolysis.

Topics: Animals; Coronary Thrombosis; Coronary Vessels; Disease Models, Animal; Dogs; Dose-Response Relationship, Drug; Drug Evaluation, Preclinical; Gamma Cameras; Infusions, Intra-Arterial; Radionuclide Imaging; Recombinant Proteins; Technetium Tc 99m Sulfur Colloid; Thrombolytic Therapy; Time Factors; Tissue Plasminogen Activator; Urokinase-Type Plasminogen Activator

Motility-stimulating drugs can increase gastric antral and intestinal contractions but do not usually enhance emptying unless gastroparesis is present. An alpha 2-adrenergic agonist (SC-39585A) was used to inhibit antroduodenal motility and simulate gastroparesis in dogs. SC-39585A caused dose-related inhibition of emptying of solid and liquid meals as well as the antral and duodenal motility responses to the solid meal. The motility-enhancing agent renzapride (100 micrograms/kg iv) did not enhance emptying of the solid meal under nondelayed conditions. However, at the same dose it partially reversed the delay in solid emptying but only when antroduodenal motility was incompletely (30 micrograms/kg sc) and not totally (100 micrograms/kg sc) inhibited by SC-39585A. This was done in part by antagonizing antral but not duodenal inhibition of motility. Renzapride was also effective orally in reversing the delay in solid emptying. Similarly, renzapride reversed the delay in liquid emptying caused by SC-39585A (30 micrograms/kg sc). An alpha 2-adrenergic agonist can be used to model gastroparesis in dogs by inhibiting antroduodenal motility and can also be used to examine the actions of motor stimulants, such as renzapride, which promote gastric emptying.

Topics: Adrenergic alpha-Agonists; Animals; Benzamides; Bridged Bicyclo Compounds; Bridged Bicyclo Compounds, Heterocyclic; Cresols; Disease Models, Animal; Dogs; Duodenum; Eating; Gastric Emptying; Gastrointestinal Motility; Muscle, Smooth; Paralysis; Pyrroles; Receptors, Adrenergic, alpha; Serotonin Antagonists; Stomach Diseases; Technetium Tc 99m Sulfur Colloid

The effect of platelet activating factor (PAF) injections on the uptake of 99mTc-SC (99mTc-SC (99mTc-sulphur colloid) was determined in vivo. PAF (2 micrograms) injected intravenously into unanaesthetized, unrestrained rats was associated with the development of lesions in the small intestine and alteration of 99mTc-SC uptake in vivo. 99mTc-SC uptake into the lung was increased while spleen uptake was decreased. Pretreatment of the animals with a PAF antagonist, SRI-64-441, prevented the intestinal lesions and alterations of 99mTc-SC uptake. Macrophages, isolated from lung lavage of the PAF-treated rats, demonstrated a decreased generation of hydrogen peroxide in vitro. The present results suggest that, in addition to its other effects on the immune system, PAF can also alter the in vivo phagocytic activity of the reticuloendothelial system in the rat.

Topics: Animals; Burns; Cecum; Disease Models, Animal; Injections, Intravenous; Intestine, Small; Mononuclear Phagocyte System; Necrosis; Platelet Activating Factor; Rats; Stomach; Technetium Tc 99m Sulfur Colloid

Comparable degree of liver cirrhosis, as judged by liver function tests and histopathology, was induced in rats by carbon tetrachloride. Comparative organ distribution of 99mTc-sulphur colloid and 99mTc-phytate was studied in the liver, spleen and lungs of these cirrhotic rats. Compared to controls, the biodistribution of 99mTc-sulphur colloid was found to be affected more than that of 99mTc-phytate in cirrhotic rats, especially at early time intervals.

Topics: Animals; Carbon Tetrachloride; Disease Models, Animal; Liver; Liver Cirrhosis, Experimental; Male; Organotechnetium Compounds; Phenobarbital; Phytic Acid; Radionuclide Imaging; Rats; Rats, Inbred Strains; Technetium Tc 99m Sulfur Colloid

A new experimentally proven method for diagnosis and localisation of acute bleeding in the flow area of the arteria mesenterica superior is reported. By selective intra-arterial nuclide injection microhemorrhage below the proof limit of angiography can be registered and relatively exact localized by additional geometric procedure. Using this method, the exact location of angiographic, negative bleedings could be determined in experimentally produced bleedings in the jejunoileal transit and in the distal ileum. We explain the experimental arrangement and the results. The diagnostic value of the examination is discussed.

Topics: Angiography, Digital Subtraction; Animals; Disease Models, Animal; Dogs; Gastrointestinal Hemorrhage; Iohexol; Mesenteric Arteries; Radionuclide Angiography; Technetium Tc 99m Sulfur Colloid

The uptake of radiolabelled colloid or bacteria was compared in normal rats and animals subjected to acute burn trauma. The uptake of colloid by the liver was unaffected by burn trauma, but uptake of the labelled bacteria was reduced. Spleen uptake of both colloid and bacteria was reduced by burn trauma while lung uptake was increased. These data are consistent with the hypothesis that acute burn trauma alters reticuloendothelial system phagocytic activity in the rat towards both inert particles and live bacteria.

Topics: Acute Disease; Animals; Burns; Disease Models, Animal; Escherichia coli; Female; Liver; Lung; Mononuclear Phagocyte System; Phagocytosis; Rats; Spleen; Technetium Tc 99m Sulfur Colloid

A canine model of distal limb lymphedema was established in order to study the treatment of this condition by lymph node transfer. This model was more difficult to establish than whole-limb lymphedema. Significant edema was achieved by a combination of preoperative irradiation and circumferential removal of skin from the irradiated areas followed by removal of the contents of the popliteal fossa. Despite these measures, it was not possible to produce lymphedema in every case, possibly because of the presence of lymphaticovenous shunts and panvascular compensation mechanisms.

Topics: Animals; Disease Models, Animal; Dogs; Hindlimb; Lymphatic System; Lymphedema; Radionuclide Imaging; Technetium Tc 99m Sulfur Colloid

Proponents of [99mTc]sulfur colloid for GI bleeding studies argue that, although labeled red blood cells are useful for intermittent bleeding, they are not capable of detecting low bleeding rates. Studies of dogs with experimental GI bleeding have indicated bleeding rates of 0.05 ml/min can be detected with [99mTc]sulfur colloid. Since similar data in the dog model were unavailable for 99mTc-labeled red blood cells, we undertook this study. To simulate lower GI bleeding, catheters were inserted into the bowel lumen. Each dog's blood was labeled with 99mTc using an in vitro technique. Venous blood was then withdrawn and re-infused into the lumen of the bowel using a Harvard pump. Fourteen dogs were studied, ten receiving a bleeding rate from 4.6-0.02 ml/min in the descending colon and four with proximal jejunal bleeds of 0.20-0.02 ml/min. Bleeding rates of 4.6-0.2 ml/min were detected within 10 min in the colon and bleeding rates as low as 0.04 ml/min were seen by 55 min. Slower bleeding rates were not detected. Similar findings were noted for proximal jejunal bleeds. Based on the time of appearance, a minimum volume of approximately 2-3 ml labeled blood was necessary to detect bleeding. We conclude that 99mTc-labeled RBCs are sensitive for low bleeding rates in the dog model. The rates are comparable to those described for [99mTc]sulfur colloid in this experimental setting. The time of appearance of activity is related to the bleeding rate.

Topics: Animals; Disease Models, Animal; Dogs; Erythrocytes; Gastrointestinal Hemorrhage; Isotope Labeling; Radionuclide Imaging; Technetium; Technetium Tc 99m Sulfur Colloid

A simple reproducible animal model of extrahepatic portal hypertension (EHPHT) has been developed in weanling Wistar rats using a two-stage ligation of the portal vein. This model consistently produces substantial collaterals, both portosystemic (hepatofugal) and portoportal (hepatopetal). Using dynamic hepatic scintigraphy (DHS) with 99mTechnetium sulphurcolloid, hepatopetal collateral flow was measured as the mesenteric fraction (MF) of total hepatic blood flow and compared with measurement of hepatofugal collateral flow (portosystemic shunting) following intraportal injection of radiolabeled microspheres. Strong and significant correlation between the two assessments was found with reduction in MF denoting increased portosystemic shunting (PSS). The technique of DHS has been used successfully in adults to assess compromised portal venous flow and is a simple noninvasive test to aid diagnosis, assessment, and follow-up of children with EHPHT.

Topics: Animals; Collateral Circulation; Disease Models, Animal; Hypertension, Portal; Ligation; Liver Circulation; Mesenteric Veins; Portal System; Portal Vein; Radiography; Radionuclide Imaging; Rats; Rats, Inbred Strains; Regional Blood Flow; Technetium Tc 99m Sulfur Colloid; Venous Pressure