Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The activities of hexokinase and glucose-6-phosphatase, as well as the in vivo metabolic products of 2-[18F]fluoro-2-deoxyglucose ([18F]FDG) (45 min after an i.v. injection), were determined from several tissues of Rous sarcoma implanted rats. The HK/G-6-Pase ratio was found to be high in brain and tumor, and low in liver with intermediate values for kidney and muscle. In accordance with the measured enzyme activities about 90% of the 18F was found as [18F]FDG-6-P in brain, heart and tumor, whereas most of its was as [18F]FDG in liver and kidney. In addition three minor metabolites, tentatively identified as nucleotide-derivatives of [18F]FDG, were formed. Our results suggest that at least Rous sarcoma tumor effectively converts [18F]FDG to [18F]FDG-6-P and thus PET studies with [18F]FDG can be applied to tumor diagnosis and to quantitative measurement of glucose utilization in tumor tissue according to the model of Sokoloff.
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PMID:Metabolism of 2-[18F]fluoro-2-deoxyglucose in tumor-bearing rats: chromatographic and enzymatic studies. 381 23

The myocardial uptake of 18F-FDG was investigated under various conditions, and compared with brain and tumor uptake as a function of blood glucose level. The uptake by the heart of normal feeding rats was rapid and remained essentially unchanged up to 2 h after 18F-FDG injection, approximately 3%-4% dose/g tissue. On the other hand, the myocardial uptake of fasted rats was significantly lower than that of control rats throughout the course of the study, and it was about 0.3%-0.4% dose/g tissue. Myocardial uptake of 18F-FDG was relatively constant at glucose levels under about 120 mg/100 ml and increased steeply at higher blood glucose levels. In contrast, brain uptake decreased linearly with increasing levels of blood glucose, revealing a strong negative correlation between brain uptake of 18F-FDG and blood glucose levels. The tumor uptake pattern remained relatively unchanged, irrespective of blood glucose levels. It was revealed that the glucose demands of brain, heart, and tumor were entirely different. After a glucose load, the myocardial uptake of fasted rats increased only slightly from 0.4% to 0.6% dose/g tissue, in spite of transitional hyperglycemia. In contrast, insulin caused myocardial uptake to increase extraordinarily, although it caused a decrease in blood glucose levels.
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PMID:Experimental studies on myocardial glucose metabolism of rats with 18F-2-fluoro-2-deoxy-D-glucose. 389 50

A comparison of the glycolytic rate as determined by positron emission tomography (PET) with 18F-deoxyglucose (FDG) and cerebral contrast computed tomography (CT) was carried out in 72 cases of cerebral glioma. FDG-PET is more accurate than contrast CT in predicting tumor grade.
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PMID:Glycolytic rate (PET) and contrast enhancement (CT) in human cerebral gliomas. 641 Jul 90

18F-2-fluoro-2-deoxy-D-glucose (18F-FDG) and 18F-2-fluoro-2-deoxy-D-mannose (18F-FDM) were tested as tumor diagnostic agents in a transplantable rat tumor and rabbit tumors. Tissue distribution studies in rats showed high tumor uptakes of both radiopharmaceuticals. The tumor uptake reached 2.65 +/- 0.61% dose 18 dose F-FDG/g and 2.65 +/- 0.81% dose 18F-FDM/g at 60 min and remained relatively constant until 120 min. Blood clearance both 18F-FDG and 18F-FDM was very rapid and tumor-to-blood ratios reached 22.1 and 29.4 at 60 min, respectively. Tumor-to-tissue ratios of both radiopharmaceuticals were very high in most organs, especially in the liver, kidney, and pancreas. Positron emission tomography (PET) of rabbit tumor with 18F-FDM clearly delineated the main tumor, central necrosis, and lymph node metastases. These data suggested that 18F-FDM, which is a by-product of 18F-FDG synthesis was also an excellent cancer diagnostic agent as well as 18F-FDG. This is not only a new feature of 18F-FDM, but also an economical improvement on cancer diagnosis by PET.
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PMID:Experimental study for cancer diagnosis with positron-labeled fluorinated glucose analogs: [18F]-2-fluoro-2-deoxy-D-mannose: a new tracer for cancer detection. 698 8

Three patients with liver metastases from colon carcinoma were studied with 2-deoxy-2-[F-18]fluoro-d-glucose (F-18-FDG) using positron emission tomography. The radioactivity in the metastatic tumor increased continuously following the injection of F-18-FDG, whereas it decreased in normal liver tissue. This resulted in the tumor to normal-liver ratio of 3.3-4.7 at 50 min after injection. The liver tumor was visualized as an increased accumulation of radioactivity in all patients, with the central area of the tumor showing less activity. These preliminary results suggest that F-18-FDG may be useful as a positive imaging agent for the detection and characterization of liver tumors.
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PMID:Increased accumulation of 2-deoxy-2-[18F]Fluoro-D-glucose in liver metastases from colon carcinoma. 698 67

Rapid uptake of F-18 FDG was observed in a variety of transplanted and spontaneous tumors in animals. The tumor uptake reached a peak by 30 min and remained relatively constant up to 60 min, with a very slow wash-out of F-18 activity from the tumor thereafter. Tumor-to-normal tissue and tumor-to-blood ratios ranged from 2.10-9.15 and 2.61-17.82, respectively, depending on the type of tumor. A scintiscan of a seminoma in a dog showed very high uptake in the viable part and lack of uptake in the necrotic mass. Toxicological studies in mice using 1000 times human tracer dose (HTD) per wk for 3 wk and in dogs using 50 times HTD per wk for 3 wk did not show any evidence of acute or chronic toxicity.
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PMID:A fluorinated glucose analog, 2-fluoro-2-deoxy-D-glucose (F-18): nontoxic tracer for rapid tumor detection. 739 42

A 49-yr-old white woman with diffuse sclerosing variant of papillary carcinoma of the thyroid revealed abnormal [18F]FDG accumulation within cervical lymph node metastases prior to thyroidectomy. The abnormal cervical foci of glucose metabolism corresponded to similar areas of abnormal [99mTc]pertechnetate and radioiodine accumulation on presurgical scans. The primary thyroid tumor within the thyroid gland was not delineated as a focal defect on any of the three imaging studies. The relative thyroid-to-background soft-tissue ratio in the [18F]FDG study, however, appeared higher than usual. As with 131I and [99mTc]pertechnetate, this case demonstrates that [18F]FDG PET can detect cervical lymph node metastases in the preoperative thyroid cancer patient.
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PMID:Cervical lymph node metastasis of thyroid papillary carcinoma imaged with fluorine-18-FDG, technetium-99m-pertechnetate and iodine-131-sodium iodide. 756 53

The use of radioactive isotopes in thyroid evaluation and therapy gives important information in the endocrine assessment of the aged. Thyroid uptake imaging can be used to establish a hypothyroid or hyperthyroid state and can determine the functional status of a palpable nodule. Investigational agents, such as T1 201m DMSA, MIBG, FDG, and Gallium are reviewed in relation to the evaluation of neoplasia. A detailed discussion of thyroid carcinoma ablation and subsequent radioiodine therapy is described, as are radiation safety procedures as they relate to the elderly.
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PMID:Radioisotopes and their use in the diagnosis and management of thyroid disease. 760 90

The diagnosis of primary lung tumors requires a precise staging according to the TNM classification. In contrast to established imaging methods 18FDG describes the functional metabolic processes in the tumor tissue due to increased glycolysis. This paper describes the use of 18FDG in the primary staging of lung tumors and metastases. 44 patients were studied with a gamma camera and a 511 keV collimator. In comparison to pulmonary tumors and metastases detected by other imaging methods (107) the accumulation of 18FDG has a sensitivity of 85%, in lesions verified by histology (50) of 89%, in primary tumors (35) of 100% and in metastases (63) of 76%. As an alternative to FDG PET studies, primary staging of lung tumors is possible with a gamma camera, suitable for ECT and fitted with a 511 keV collimator.
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PMID:[18FDG in the primary staging of lung tumors. Results with a gamma camera and a 511 keV collimator]. 763 Jul 46

Long-circulating liposomes are known to accumulate passively in tumor tissues of tumor-bearing animals. To evaluate the in vivo behavior of such liposomes, we investigated the real-time liposomal trafficking by a non-invasive method using position emission tomography (PET). Liposomes composed of dipalmitoylphosphatidylcholine, cholesterol, and palmityl-D-glucuronide (PGlcUA) in a molar ratio of 4:4:1 were prepared in the presence of 2-[18F]fluoro-2-deoxyglucose ([2-18F]FDG). [2-18F]FDG-labeled liposomes sized by extrusion through a filter with various-sized pores were administered to mice bearing Meth A sarcoma, and a PET scan was performed for 120 min. Small-sized, long-circulating liposomes (100 nm in diameter) constructed with PGlcUA tended to accumulate in the tumor tissues. On the contrary, control liposomes (100 nm in diameter) containing dipalmitoylphosphatidylglycerol instead of PGlcUA accumulated in the liver. Large-sized PGlcUA-containing liposomes (> 300 nm) also accumulated in the liver, as well as in the spleen. Time-activity curves indicated that the small long-circulating liposomes (< 200 nm) transiently accumulated in the liver right after the injection but that the accumulation there decreased time-dependently. These data suggest that, although the majority of small long-circulating liposomes remain in the bloodstream, some extravasate once into the interstitial spaces in the liver re-enter the bloodstream again, and finally accumulate in the tumor tissues. This PET technique might be useful for studying real-time liposomal trafficking and for tumor imaging.
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PMID:Real-time analysis of liposomal trafficking in tumor-bearing mice by use of positron emission tomography. 765 55


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