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Evaluation of the Potential of Microspherical Systems for Regional Therapy in the Tumor-Bearing Liver and Kidney Using Techniques in Nuclear Medicine
Published in Neville Willmott, John Daly, Microspheres and Regional Cancer Therapy, 2020
Jacqueline A. Goldberg, James H. McKillop, Colin S. McArdle
In marked contrast to other imaging tests, nuclear medicine investigations evaluate function of the area studied rather than anatomy. When a radiopharmaceutical is injected, it will localize in a target organ as a result of some functional aspect of the organ. Thus, radioactive iodine is trapped by the thyroid using the physiological iodide trap. Technetium-99m (99mTc) can substitute for iodide in this trap and will thus be retained by the thyroid, although it will not be incorporated into the thyroid hormone synthetic pathway. Thallium-201 will substitute for potassium in the ATP-ase dependent sodium-potassium pump, which enables it to be used as a myocardial imaging agent. The 99mTc-iminodiacetic acid compounds are excreted by the liver by the same mechanism as bilirubin, which allows them to be used as biliary imaging agents.
Radioisotopes in Biology and Medicine
Published in Kedar N. Prasad, Handbook of RADIOBIOLOGY, 2020
67Ga-labeled citrate injection can detect over 90% of hepatocellular carcinoma; however, only 50 of metastases accumulate radioactive gallium. 67Ga-labeled citrate or 111In-oxine-labeled autologous leukocytes are often used to detect intra- or extrahepatic sepsis; vascular lesions in the liner can be detected by 99mTc-labeled human serum albumin or 99Tc-labeled red blood cells. Nuclides of 111In and 113mIn, when injected intravenously, attach to circulating transferrin, and images are taken by an appropriate pulse-height analyzer window set to exclude the 99mTc. Among radionuclide agents for imaging of the hepatobiliary system 99mTc-labeled iminodiacetic acid (IDA) is the best for routine clinical purposes. When assessment of biliary drainage is required over a period of several days, 99mTc with a half-life of 6 hr may not be adequate for this purpose. 97Ru with a longer half-life may be adequate.
Radiology of Infectious Diseases and Their Potential Mimics in the Critical Care Unit
Published in Cheston B. Cunha, Burke A. Cunha, Infectious Diseases and Antimicrobial Stewardship in Critical Care Medicine, 2020
Jocelyn A. Luongo, Boris Shapiro, Orlando A. Ortiz, Douglas S. Katz
Nuclear scintigraphic examinations are useful in confirming cholecystitis and for differentiating between acute and chronic forms in selected patients. 99m-Tc iminodiacetic acid derivatives (i.e., hepatobiliary iminodiacetic acid [HIDA] and its derivatives) are injected intravenously, are taken up by hepatocytes, and are then transported into the biliary system in a fashion similar to bilirubin. Non-visualization of the gallbladder at four hours has a 99% specificity for diagnosing cholecystitis. Intravenous morphine may be administered if initial images do not demonstrate the gallbladder, to cause sphincter of Oddi spasm, increasing biliary pressure and forcing radiotracer into a chronically inflamed gallbladder, but not in acute gallbladder inflammation [3].
Duodenal bulb obstruction caused by a gallstone (Bouveret syndrome) successfully treated with endoscopic measures
Published in Baylor University Medical Center Proceedings, 2020
Gilles Jadd Hoilat, Vanessa Sostre, Judie N. Hoilat, Ceren Durer, Seren Durer, Gowthami Kanagalingam, Divey Manocha
On postoperative day 1, there was biliary drainage in the Blake drain. A hepatobiliary iminodiacetic acid scan came back negative and a subsequent computed tomography scan showed no definite evidence of peripheral contrast enhancement suggestive of postsurgical fluid with air. Days later, there was still concern for high output from the drain and she was evaluated by the gastroenterology service for endoscopic retrograde cholangiopancreatography (ERCP). An endoscopic procedure showed that the duodenal bulb was impacted with a large 3 cm stone (Figure 1a, 1b), causing gastric outlet obstruction. The impacted stone was successfully removed with a snare (Figure 1c, 1d). A small bile leak was found at the cystic duct stump; a 10 mm size biliary sphincterotomy was performed and one plastic stent was placed in the common bile duct with bile drainage. Upon review of previous imaging and the surgical report and discussion with the surgical team, there was no evidence of any sort of fistula that would normally lead to the gastric outlet obstruction. After ERCP, the patient experienced marked improvement of her symptoms. She was tolerating her diet and subsequently was discharged home.
Alpha-ketoglutarate mediated hepatoprotection against alcohol induced toxicity: in vivo functional observation studies in Sprague Dawley rats using gamma scintigraphy
Published in Drug and Chemical Toxicology, 2020
Lalita Mehra, Harish Rawat, Abhinav Jaimini, Amit Tyagi, Gaurav Mittal
Mebrofenin, a hepatic-iminodiacetic acid (HIDA) derivative is pharmacologically an innate molecule. Following intravenous injection, this radiotracer is rapidly cleared from the blood pool by high first pass hepatic extraction (∼98%). The mechanism of its uptake and excretion by hepatocytes is postulated to involve receptors similar to those for free fatty acids, bile salts, bilirubin, and non-cholephil organic anions. It is secreted into bile canaliculi and subsequently from intrahepatic biliary radicles (IHBR) to intestine in the native state with no involvement of intracellular metabolic processes. Only 0.4 to 2% of injected dose is found to be excreted through urine. Thus, mebrofenin is considered to be an ideal tracer for quantification of hepatobilliary functioning (Ghibellini et al. 2008).
Therapeutic biomaterials based on extracellular vesicles: classification of bio-engineering and mimetic preparation routes
Published in Journal of Extracellular Vesicles, 2018
Pablo García-Manrique, María Matos, Gemma Gutiérrez, Carmen Pazos, María Carmen Blanco-López
The most frequent preparation technique for SUVs as templates for EVs mimicking is the TFH method combined with extrusion over polycarbonate membranes and with [102] or without [15] previous freeze–thaw cycles. Martínez-Lostao et al. [102] had a formulation that included lipids and stoichiometry inspired in natural exosomes. The introduction of only 5% (w/w) of an iminodiacetic acid derivative or DOGS-NTA allowed the binding of APO2L/TRAIL-His10 to liposomes in a single step. Its bioactivity was a higher activity than that of the soluble ligand. Moreover, a treatment based on these synthetic exosomes achieved 60% of disease improvement in a rheumatoid arthritis-induced animal model. In another study, liposome-bound Apo2L/TRAIL overcame the resistance to the soluble ligand exhibited by chemorresistive tumour cell mutants [106]. The mechanism of action of LUV-TRAIL in haematologic cells [107] was also studied using mimetic structures of exosomes.