Journal of nuclear medicine : official publication, Society of Nuclear Medicine
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Technetium-99m-hexamethylpropylene amine oxime (HMPAO) brain images with fanbeam SPECT, in combination with surface three-dimensional display, were used to detect basal ganglion and cerebral cortex anomalies in the acute phase of carbon monoxide (CO) poisoning. ⋯ This study suggests that, in comparison with traditional brain imaging techniques, 99mTc-HMPAO brain imaging with fanbeam SPECT in combination with surface three-dimensional display is a better tool for early detection of regional cerebral anomalies in acute CO poisoning.
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Case Reports
Cerebral perfusion imaging in asymptomatic carotid artery occlusion following gun shot.
Recognition of brain injury in asymptomatic carotid artery injuries with conventional methods can be difficult. We present a case of angiographically proven asymptomatic left internal carotid artery occlusion with normal CT after a gunshot wound. The SPECT brain perfusion imaging showed mild generalized supratentorial hypoperfusion of the bilateral cerebral cortices on the left side and severe left temporal lobe hypoperfusion.
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Chimeric T84.66 (cT84.66) is a high-affinity (1.16 x 10[11] M[-1]) IgG1 monoclonal antibody (MAb) against carcinoembryonic antigen (CEA). This pilot trial evaluated the tumor-targeting properties, biodistribution, pharmacokinetics and immunogenicity of 111In-labeled cT84.66. ⋯ Chimeric T84.66 demonstrated tumor targeting that was comparable to that of other radiolabeled intact anti-CEA Mabs. Its immunogenicity after single administration was lower than murine Mabs. These properties make cT84.66 or a lower molecular weight derivative attractive for further evaluation as an imaging agent. These same properties also make it appropriate for future evaluation in Phase I therapy trials. Finally, a wide variation in the rate of antibody clearance was observed, with one patient demonstrating very slow clearance, resulting in the highest estimated marrow dose of the group, and one patient demonstrating unusually rapid clearance, resulting in poor antibody localization to tumor. Data from this study suggest that serum CEA levels, antibody-antigen complex clearance and, therefore, antibody clearance are influenced by both the production and clearance rates of CEA. This underscores the need to further identify, characterize and understand those factors that influence the biodistribution and clearance of radiolabeled anti-CEA antibodies to allow for better selection of patients for therapy and rational planning of radioimmunotherapy.
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Randomized Controlled Trial Comparative Study Clinical Trial
Longer occupancy of opioid receptors by nalmefene compared to naloxone as measured in vivo by a dual-detector system.
Surgical procedures usually involve the administration of narcotic drugs as anesthetics or adjuvants. To reverse the effects of anesthesia, opioid antagonists such as naloxone are commonly used. Due to its short lasting effects, patients receiving naloxone must be monitored carefully. Nalmefene, a pure opiate antagonist with a longer duration of action than naloxone, has shown promise in the reversal of opioid anesthesia. ⋯ These findings suggest that the prolonged effects of nalmefene are related to the slow dissociation of nalmefene from opioid receptors, which are not reflected in the plasma curve. This longer blockade of opioid receptors by nalmefene represents an advantage in the clinical management of postsurgical reversal of narcotic anesthesia and opioid side effects as well as the reversal of opioid overdose.
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Quantitative assessment of atherosclerotic or atherothrombotic disease during its natural history and following therapeutic interventions is important for understanding the progression and stabilization of the disease and for selecting appropriate medical or surgical interventions. A number of invasive and noninvasive imaging techniques are available to detect and display different characteristics of vascular lesions of clinical and/or research interest. ⋯ Magnetic resonance angiography, being noninvasive, may replace conventional angiography for anatomical imaging of the vasculature. Ultrafast electron beam CT measures the calcium content in the atherosclerotic lesions. Intravascular ultrasound is the only technique that appears to be clinically useful in imaging the unstable, vulnerable plaques in coronary arteries. Magnetic resonance imaging techniques may be able to image vulnerable plaques and characterize plaques in terms of lipid and fibrous content and identify the presence of thrombus associated with the plaques. In regard to the nuclear scientigraphic imaging techniques, radiolabeled lipoproteins, platelets and immunoglobulins have shown some clinical potential as imaging agents, but due to poor target-to-background and target-to-blood ratios these agents are not ideal for imaging coronary or even carotid lesions. Technetium-99m-labeled peptides and monoclonal antibody fragments that clear from circulation rapidly and bind specifically to different components of the atherosclerotic lesion showed significant potential in animal models and in limited clinical studies. FRE Peptides capable of binding to GPIIb/IIIA receptors on activated platelets appear to offer significant diagnostic potential for imaging intra-arterial thrombus. Positron emission tomography with metabolic tracers like [18F]-fluorodeoxyglucose (FDG) also appears to offer new opportunities for noninvasive imaging of atherosclerosis and atherothrombosis.