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  • 1
    Electronic Resource
    Electronic Resource
    Invalidity of Criticisms of the Deoxyglucose Method Based on Alleged Glucose-6-Phosphatase Activity in Brain (1986)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 46 (1986), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The observations made by Sacks et al. [Neurochem. Rea.8, 661–685 (1983)] on which they based their criticisms of the deoxyglucose method have been examined and found to have no relationship to the conclusions drawn by them. (1) The observations of Sacks et al. (1983) of constant concentrations of [14C]deoxyglucose and [14C]deoxyglucose-6-phosphate. predominantly in the form of product, reflects only the postmortem phosphorylation of the precursor during the dissection of the brain in their experiments. When the brains are removed by freeze-blowing, the time courses of the [14C]deoxyglucose and [14C]deoxyglucose-6-phos-phate concentrations in brain during the 45 min after the intravenous pulse are close to those predicted by the model of the deoxyglucose method. (2) Their observation of a reversal of the cerebral arteriovenous difference from positive to negative for [14C]deoxyglucose and not for [14C]glucose after an intravenous infusion of either tracer is, contrary to their conclusions, not a reflection of glucose-6-phosphatase activity in brain but the consequence of the different proportions of the rate constants for efflux and phosphorylation for these two hexoses in brain and is fully predicted by the model of the deoxyglucose method. (3) It is experimentally demonstrated that there is no significant arteriovenous difference for glucose-6-phosphate in brain, that infusion of [12P]glucose-6-phosphate results in no labeling of brain, and that the blood-brain barrier is impermeable to glucose-6-phosphate. Glucose-6-phosphate cannot, therefore, cross the blood-brain barrier, and the observation by Sacks and coworkers [J. Appl. Physiol.24, 817–827 (1968); Neuro-chein. Res.8, 661–685 (1983)J of a positive cerebral arteriovenous difference for [14C]glucose-6-phosphate and a negative arteriovenous difference for [14C]glucose cannot possibly reflect glucose-6-phosphatase activity in brain as concluded by them. Each of the criticisms raised by Sacks et al. has been demonstrated to be devoid of validity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1986.tb13057.x
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  • 2
    Electronic Resource
    Electronic Resource
    Optimal Duration of Experimental Period in Measurement of Local Cerebral Glucose Utilization with the Deoxyglucose Method (1990)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 54 (1990), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The time course and magnitude of the effects of product loss on the measurement of local cerebral glucose utilization (LCGU) by the 2-[14C]deoxyglucose (DG) method were studied by determination of LCGU in 38 rats with 25–120 min experimental periods after a [14C]DG pulse and in 45 rats with experimental periods of 2.5–120 min during which arterial plasma [14C]DG concentrations (CP*) were maintained constant. LCGU was calculated by the operational equation, which assumes no product loss, with the original set of rate constants and with a new set redetermined in the rats used in the present study; in each case the rate constants were those specific to the structure. Data on local tissue 14C concentrations and CP* were also plotted according to the multiple time/graphic evaluation technique (“Patlak Plot”). The results show that with both pulse and constant arterial inputs of [14C]DG the influence of the rate constants is critical early after onset of tracer administration but diminishes with time and becomes relatively minor by 30 min. After a [14C]DG pulse calculated LCGU remains constant between 25 and 45 min, indicating a negligible effect of product loss during that period; at 60 min it begins to fall and declines progressively with increasing time, indicating that product loss has become significant. When CP* is maintained constant, calculated LCGU does not change significantly over the full 120 min. The “Patlak Plots” reinforced the conclusions drawn from the time courses of calculated LCGU; evidence for loss of product was undetectable for at least 45 min after a pulse of [14C]DG and for at least 60 min after onset of a constant arterial input of [14C]DG.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1990.tb13316.x
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  • 3
    Electronic Resource
    Electronic Resource
    Spatial registration of echocardiographic and positron emission tomographic heart studies (1995)
    Springer
    European journal of nuclear medicine 22 (1995), S. 243-247 
    Details
    ISSN: 1619-7089
    Keywords: Echocardiography ; Positron emission tomography ; Fluorine-18-fluoro-2-deoxy-d-glucose ; Registration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A method has been developed to match corresponding heart regions from functional echocardiographic (Echo) and metabolic fluorine-l8-fluoro-2-deoxy-d-glucose ([18F]FDG) positron emission tomography (PET) studies in individual patients. Echo and PET images are spatially correlated by determining homologous anatomical landmarks (the two papillary muscles and the inferior junction of the right ventricle), identifiable in images obtained by both acquisition modalities. Echo-PET image registration is first performed in the plane identified by the three landmarks, using a rigid rotate-translate scale model. The registration parameters are then used to transform the whole PET volume. This allows a consistent Echo-PET regional analysis, according to a segmental subdivision of the heart. The technique was tested on patients. The overlay of Echo and PET registered images proved the reliability of realignment of the three markers and a good spatial correlation of myocardial walls. This approach to image registration could be applied to other acquisition modalities (such as magnetic resonance imaging and single-photon emission tomography), provided that the three anatomical landmarks are visualized.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01081520
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  • 4
    Electronic Resource
    Electronic Resource
    Double-blind stereo-EEG and FDG PET study in severe partial epilepsies: Are the electric and metabolic findings related? (1996)
    Springer
    European journal of nuclear medicine 23 (1996), S. 1498-1507 
    Details
    ISSN: 1619-7089
    Keywords: Drug-resistant partial epilepsy ; Positron emission tomography ; Stereo-electroencephalography ; Fluorine-18 fluorodeoxyglucose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The aim of this study was to evaluate, in 16 patients with drug-resistant partial epilepsy who were waiting to undergo surgical treatment, the relation between positron emission tomography (PET) findings with fluorine-18 fluorodeoxyglucose ([18F]FDG) in the interictal state and the different stereo-electroencephalography (SEEG) patterns that characterize: (a) the epileptogenic zone (low-voltage fast-activity discharge before or concurrent with ictal clinical symptoms), (b) the irritative zone (spikes, spikes and waves, isolated or grouped in short bursts) and (c) the lesional zone (continuous, sometimes polyrhythmic slow waves or continuous delta waves or very important voltage depression). SEEG was performed following an individually defined electrode implantation strategy. Whereas at least one area of hypometabolism was detected by visual interpretation of PET/[18F]FDG images in all the subjects in the study, there was poor agreement between PET/[18F]FDG quantitative measures of regional metabolism and SEEG findings. Normal metabolic rates were found in up to 62% of the areas with abnormal SEEG activity, independent of the type of electrical activity, i.e. epileptogenic, irritative, or lesional, while abnormal metabolic rates were found in up to 23% of the areas with normal SEEG activity. In conclusion, whereas the visual interpretation of interictal studies of glucose utilization in our series of drug-resistant epileptic patients consistently allowed the localization of an area of temporal hypometabolism, the quantitative and regional metabolic analysis demonstrated that such a finding is not specifically related to any of the three very different SEEG patterns (epileptogenic, irritative, lesional) or combinations thereof. These results complement those of previous interictal and ictal single-photon emission tomographic studies and of receptor studies in epileptics, suggesting functional and biochemical heterogeneity within the interictal hypoperfused/hypometabolic area in epileptic patients, and contribute to the debate on the use and interpretation of interictal PET/[18F]FDG studies in patients with medically refractory partial seizures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01254475
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  • 5
    Electronic Resource
    Electronic Resource
    Differentiation of clinically non-functioning pituitary adenomas from meningiomas and craniopharyngiomas by positron emission tomography with [18F]fluoro-ethyl-spiperone (1997)
    Springer
    European journal of nuclear medicine 24 (1997), S. 1149-1155 
    Details
    ISSN: 1619-7089
    Keywords: Key words: Pituitary ; Neoplasm ; Dopaminergic ; Receptor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The differential diagnosis among various types of non-functioning sellar and parasellar tumours is sometimes difficult using currently available methods of morphological imaging. The aim of this study was to define whether assessment of the uptake of [18F]fluoro-ethyl-spiperone (FESP) with positron emission tomography (PET) could be helpful for the differential diagnosis of pituitary adenomas and other parasellar lesions, and for establishing the appropriate therapeutic approach. The population examined comprised 16 patients with the diagnosis of primary tumour of the sellar/parasellar region who were waiting to undergo surgical treatment. The results demonstrated that PET with [18F]FESP is a very specific method for differentiating adenomas from craniopharyngiomas and meningiomas. The visual interpretation of images allows such differentiation at approximately 70 min after tracer injection. Semiquantitative analysis of the dynamic PET data confirmed the results of visual interpretation, demonstrating that the uptake of [18F]FESP was consistently (i.e. throughout the series) at least two- to threefold higher in non-functioning adenomas than in other parasellar tumours as early as 70 min after tracer injection, and that it increased still further thereafter. It is concluded that PET with [18F]FESP might be of clinical value in those cases in which the differential diagnosis among various histological types of sellar tumour is uncertain with conventional methods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01254248
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  • 6
    Electronic Resource
    Electronic Resource
    Differentiation of clinically non-functioning pituitary adenomas from meningiomas and craniopharyngiomas by positron emission tomography with [18F]fluoro-ethyl-spiperone (1997)
    Springer
    European journal of nuclear medicine 24 (1997), S. 1149-1155 
    Details
    ISSN: 1619-7089
    Keywords: Pituitary ; Neoplasm ; Dopaminergic ; Receptor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The differential diagnosis among various types of non-functioning sellar and parasellar tumours is sometimes difficult using currently available methods of morphological imaging. The aim of this study was to define whether assessment of the uptake of [18F]fluoro-ethyl-spiperone (FESP) with positron emission tomography (PET) could be helpful for the differential diagnosis of pituitary adenomas and other parasellar lesions, and for establishing the appropriate therapeutic approach. The population examined comprised 16 patients with the diagnosis of primary tumour of the sellar/parasellar region who were waiting to undergo surgical treatment. The results demonstrated that PET with [18F]FESP is a very specific method for differentiating adenomas from craniopharyngiomas and meningiomas. The visual interpretation of images allows such differentiation at approximately 70 min after tracer injection. Semiquantitative analysis of the dynamic PET data confirmed the results of visual interpretation, demonstrating that the uptake of [18F]FESP was consistently (i.e. throughout the series) at least two- to threefold higher in non-functioning adenomas than in other parasellar tumours as early as 70 min after tracer injection, and that it increased still further thereafter. It is concluded that PET with [18F]FESP might be of clinical value in those cases in which the differential diagnosis among various histological types of sellar tumour is uncertain with conventional methods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01254248
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    Paper (German National Licenses)
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