No abstract available

[en] A radioimmunoassay was developed to measure calmodulin in striatum from rats treated with one dose or repeated injections of amphetamine. Chronic, but not acute, amphetamine treatment resulted in a significant increase in total calmodulin levels in striatal homogenates. This effect may be linked to the behavioral sensitization which develops after chronic amphetamine treatments. (Auth.)

[en] Regional cerebral blood flow (rCBF) was measured with xenon-enhanced CT (Xe-CT) in 21 cases of intracranial tumors (13 meningiomas, 5 gliomas, 3 metastatic brain tumors). Peritumoral edema was graded as mild, moderate or severe based on the extent of edema on CT and MRI. According to intratumoral blood flow distribution patterns, three patterns were classified as central type with relatively high blood flow at the center of the tumor, homogeneous type with an almost homogeneous blood flow distribution, and marginal type with relatively high blood flow at the periphery of the tumor. High grade astrocytoma and metastatic brain tumor showed marginal type blood flow and moderate or severe edema except in one case. Five meningiomas with severe peritumoral edema revealed marginal type blood flow and four with mild peritumoral edema showed central type blood flow, except for one case. No correlation was found between the extent of peritumoral edema and histological subtype, tumor size, location, duration of clinical history, vascularization on angiogram, and mean blood flow in the tumor. These results suggest that blood flow distribution patterns within the tumor may affect the extension of peritumoral edema. Pre- and postoperative rCBFs were evaluated with Xe-CT and IMP-SPECT in 7 cases, mean rCBF of peritumoral edema was 6.2 ml/100 g/min preoperatively, and discrepancy between rCBF on Xe-CT and that on IMP-SPECT was shown in the remote cortical region ipsilateral to the tumor. Postoperative rCBF revealed an improved blood flow in both adjacent and remote areas, suggesting that the decreased blood flow associated with brain tumors might be relieved after surgery. (author) 53 refs

[en] The presence of Cu(II) in the isotopic exchange reaction for the labelling of N-isopropyl-para-iodo-amphetamine with ¹²³I is proven to cause radioiodinated as well as cold side-products. The use of Cu(I) for promoting the nucleophilic isotopic exchange in the presence of an excess of reductant, such as Sn(II) or ascorbic acid, allows an almost quantitative yield to be obtained within 20 minutes. The reaction is assumed to proceed through an organo-copper complex favouring the exchange of the radioiodide. The labelling procedure is suitable to be adapted as a kit-form preparation. (author)

[en] Neural pathway for visual information processing involves retina, lateral geniculate body, primary visual cortex, and higher visual cortical areas, all of which have been reported to be disordered either functionally or pathologically in Parkinson disease (PD). As elementary visual disorders, there have been studies that reported reduced contrast sensitivity for middle to high spatial frequencies and impaired blue color perception. Most of those studies suggested retina as the damaged cite that is responsible for the impairments, whereas some studies pointed to the possible cortical involvement. Impairments of higher visual functions also have been reported. In the dorsal stream, impairments of object localization, depth perception, and mental rotation have been reported. In the ventral stream, object perception and visual integration of objects have been found to be impaired. A meta-analysis study, however, concluded that although there may be impairments in higher order functions like attention and problem solving capacity there is no firm evidence for the impairments of higher visual functions. Neuroimaging studies have found a relationship between reduced metabolism centered in the parietal lobe and impaired performance in higher visual functions. Impaired identification of overlapping figures has been reported in dementia with Lewy bodies a disease that is akin to PD. Capacity to discriminate textured areas has been found to be damaged in PD. We conducted a fluorodeoxyglucose-positron emission tomography (FDG-PET) study to explore the relationship between brain metabolism and perception of overlapping figures, perception of shapes defined by texture differences and perception of subjective contours in PD. It revealed that there is a correlation between reduced activation in lateral occipital complex and impaired performance for these tasks, suggesting some compromised ventral rout functions. (author)

[en] In 14 patients with radiologically proven pulmonary lesions, factor analysis was performed for pulmonary scintigrams with N-isopropyl-p[I-123]iodoamphetamine (I-123 IMP). Pulmonary areas extracted by factor analysis were coincident with areas of decreased activities on first pass images in ll patients. In the other three patients with space-occupying lesions which showed discordance between first pass and factor analysis studies, photon deficiency was observed on 5-hr images. Factor analysis clearly depicted a decreased or deficient blood flow of the pulmonary area as an abnormal factor in all patients. Factor analysis would replace delayed images because of its advantage of extracting abnormal blood flow of the pulmonary artery, and aid in the evaluation of residual pulmonary tissue because of its ability to differentiate space-occupying lesions from inflammatory tissues. (Namekawa, K)

[en] N-isopropyl-p-[¹²³I]iodoamphetamine (¹²³I-IMP) was injected intravenously into primary non small cell lung carcinoma patients (n=17). The average pixel count ratios of the cancerous area to the whole lung was measured in the initial and delayed images. In the initial image, this ratio was less than 1.0 for the entire group of patients, and was thought to reflect decreased blood flow in the cancerous tissues. The rate of counts within a ROI in the delayed image to counts in the same ROI in the initial image was also calculated and called the remain rate. The remain rate (delayed count/initial count) was significantly higher in the cancerous area than in the whole lung (0.65±0.30, median 0.62, 0.38±0.05, median 0.38, p<0.01). This observation was thought to be due to a relative decrease in the blood flow and the accumulation of IMP, which forms pools within the alveolar spaces of the cancerous areas. The image prepared with the remain rate revealed a hot image in the cancerous regions, even when this was not apparent in the delayed image. The remain rate image may therefore be useful in the identification of cancerous areas in lung tissue if it is used in comparison with the initial image. (author)

[en] A simple method of preparation of the radiopharmaceutical N-isopropyl-p-(¹²³I)-iodoamphetamine is described involving limited manipulation and offering high production yields. The reaction mixture, which includes N-isopropyl-p-iodoamphetamine, sodium ¹²³I iodide in NaOH, glacial acetic acid and cupric sulphate was immersed in a 140⁰C equilibrated oil bath and refluxed for 1-2h. An iodine trap trapped volatilized ¹²³I iodide. The absence of ¹²³I iodide in the final preparation was checked by TLC. (U.K.)

[en] We developed a new analysis algorithm based on multiple-time graphical plot to estimate the regional cerebral blood flow and partition coefficient using dynamic SPECT and N-isopropyl-p-[¹²³I]iodoamphetamine (¹²³I-IMP). By assuming the 2-compartment model of the kinetic for ¹²³I-IMP, we derived a linear relationship between the ratio of the tissue activity concentration at the times to the time-integral arterial concentration at the respective times [Y(t)=C_b(t)/∫₀^tC_a(s)ds] and the ratio of the time-integral tissue concentration to the time-integral arterial concentration [X(t) = ∫₀^t C_b(s)ds/∫₀^t C_a(s)ds], and demonstrated that the Y-intercept and X-intercept of the plot line represent the regional cerebral blood flow (K₁) and partition coefficient (λ), respectively. The slope of the line represents a clearance constant k₂. The present method was applied to data on four normal subjects measured by dynamic SPECT. Values of the K₁ and λ for the gray matter were obtained 40.8±6.5 ml/100 g/min and 28.8±5.3 ml/g, respectively, and the corresponding values for the white matter were 29.1±4.7 ml/100 g/min and 28.1±7.1 ml/g. The new method enabled a rapid estimation of both K₁ and λ. (author)

[en] A method of quantitatively analyzing ECT sections obtained from cerebral perfusion/function studies with N-isopropyl-p-I-123 Amphetamine (IMP) is presented and illustrated by a concrete case. This analysis makes use of six pairs of regions delineating the perfusion territories of the major cerebral arteries, and produces six right-left ratios which provide objective criteria to assess pathology and, in our opinion, is an important adjunct to visual interpretation of IMP studies. Even though quantitation of rCBF with IMP is highly desirable, no satisfactory method short of arterial input sampling seems to have been used so far to obtain absolute blood flow values. (orig.)