1,723,224 research outputs found
Stenella coeruleoalba (striped dolphin) - CVM-9470
No full textStenella coeruleoalba (striped dolphin) - CVM-9470 - unknown sex - 2.26 m - Pelvic location - Vancouver Museu
18F-MK-9470 PET imaging of the type 1 cannabinoid receptor in prostate carcinoma: a pilot study
No full textBACKGROUND: Preclinical and histological data show overexpression of the type 1 cannabinoid receptor (CB1R) in prostate carcinoma (PCa). In a prospective study, the feasibility of 18F-MK-9470 positron emission tomography (PET) imaging in patients with primary and metastatic PCa was evaluated. METHODS: Eight patients were included and underwent 18F-MK-9470 PET/CT imaging. For five patients with primary PCa, dynamic PET/CT imaging was performed over three acquisition intervals (0 to 30, 60 to 90 and 120 to 150 min post-injection). In malignant and benign prostate tissue regions, time activity curves of the mean standardized uptake value (SUVmean) were determined as well as the corresponding area under the curve to compare 18F-MK-9470 uptake over time. Muscle uptake of 18F-MK-9470 was used as reference for non-specific binding. Magnetic resonance imaging (MRI) was used as anatomical reference and for delineating intraprostatic tumours. Histological and immunohistochemical (IHC) examination was performed on the whole-mount histopathology sections of four patients who underwent radical prostatectomy to assess the MRI-based tumour versus benign tissue classification. For three patients with proven advanced metastatic disease, two static PET/CTs were performed 1 and 3 h post-injection. 18F-MK-9470 uptake was evaluated in bone lesions of metastatic PCa by comparing SUVmean values of metastases with these of the contralateral bone tissue. RESULTS: 18F-MK-9470 uptake was significantly higher in benign and malignant prostate tissue compared to muscle, but it did not differ between both prostate tissue compartments. IHC findings of corresponding prostatic histopathological sections indicated weak CB1R expression in locally confined PCa, which was not visualized with 18F-MK-9470 PET. Metastases in the axial skeleton could not be detected while some metastases in the appendicular skeleton showed higher 18F-MK-9470 uptake as compared to the uptake in contralateral normal bone. CONCLUSIONS: 18F-MK-9470 PET could not detect local PCa or bone metastases in the axial skeleton but was able to visualize metastases in the appendicular skeleton. Based on these pilot observations, it seems unlikely that CB1R PET will play a significant role in the evaluation of PCa
18F-MK-9470 PET imaging of the type 1 cannabinoid receptor in prostate carcinoma: a pilot study
Full text linkBACKGROUND:
Preclinical and histological data show overexpression of the type 1 cannabinoid receptor (CB1R) in prostate carcinoma (PCa). In a prospective study, the feasibility of 18F-MK-9470 positron emission tomography (PET) imaging in patients with primary and metastatic PCa was evaluated.
METHODS:
Eight patients were included and underwent 18F-MK-9470 PET/CT imaging. For five patients with primary PCa, dynamic PET/CT imaging was performed over three acquisition intervals (0 to 30, 60 to 90 and 120 to 150 min post-injection). In malignant and benign prostate tissue regions, time activity curves of the mean standardized uptake value (SUVmean) were determined as well as the corresponding area under the curve to compare 18F-MK-9470 uptake over time. Muscle uptake of 18F-MK-9470 was used as reference for non-specific binding. Magnetic resonance imaging (MRI) was used as anatomical reference and for delineating intraprostatic tumours. Histological and immunohistochemical (IHC) examination was performed on the whole-mount histopathology sections of four patients who underwent radical prostatectomy to assess the MRI-based tumour versus benign tissue classification. For three patients with proven advanced metastatic disease, two static PET/CTs were performed 1 and 3 h post-injection. 18F-MK-9470 uptake was evaluated in bone lesions of metastatic PCa by comparing SUVmean values of metastases with these of the contralateral bone tissue.
RESULTS:
18F-MK-9470 uptake was significantly higher in benign and malignant prostate tissue compared to muscle, but it did not differ between both prostate tissue compartments. IHC findings of corresponding prostatic histopathological sections indicated weak CB1R expression in locally confined PCa, which was not visualized with 18F-MK-9470 PET. Metastases in the axial skeleton could not be detected while some metastases in the appendicular skeleton showed higher 18F-MK-9470 uptake as compared to the uptake in contralateral normal bone.
CONCLUSIONS:
18F-MK-9470 PET could not detect local PCa or bone metastases in the axial skeleton but was able to visualize metastases in the appendicular skeleton. Based on these pilot observations, it seems unlikely that CB1R PET will play a significant role in the evaluation of PCa.status: Publishe
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Kinetic Analysis of the Cannabinoid-1 Receptor PET Tracer [18F] MK-9470 in Human Brain
Full text linkPURPOSE:
Quantitative imaging of the type 1 cannabinoid receptor (CB1R) opens perspectives for many neurological and psychiatric disorders. We characterized the kinetics and reproducibility of the CB1R tracer [(18)F]MK-9470 in human brain.
METHODS:
[(18)F]MK-9470 data were analysed using reversible models and the distribution volume V (T) and V (ND) k (3) (V (ND) k (3) = K (1) k (2)) were estimated. Tracer binding was also evaluated using irreversible kinetics and the irreversible uptake constant K (i) and fractional uptake rate (FUR) were estimated. The effect of blood flow on these parameters was evaluated. Additionally, the possibility of determining the tracer plasma kinetics using a reduced number of blood samples was also examined.
RESULTS:
A reversible two-tissue compartment model using a global k (4) value was necessary to describe brain kinetics. Both V (T) and V (ND) k (3) were estimated satisfactorily and their test-retest variability was between 10% and 30%. Irreversible methods adequately described brain kinetics and FUR values were equivalent to K (i). The linear relationship between K (i) and V (ND) k (3) demonstrated that K (i) or FUR and thus the simple measure of tracer brain uptake provide CB1R availability information. The test-retest variability of K (i) and FUR was <10% and estimates were independent of blood flow. Brain uptake can be used as a receptor availability index, albeit at the expense of potential bias due to between-subject differences in tracer plasma kinetics.
CONCLUSION:
[(18)F]MK-9470 specific binding can be accurately determined using FUR values requiring a short scan 90 to 120 min after tracer administration. Our results suggest that [(18)F]MK-9470 plasma kinetics can be assessed using a few venous samples.status: Publishe
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
The effect of anesthesia on [18F]MK-9470 binding to the type 1 cannabinoid receptor in the rat brain
Full text linkPURPOSE: Small animal PET can be applied to study molecular processes in animal models of a variety of human diseases. In order to keep the animals in a restricted position during imaging, anaesthesia is in many instances inevitable. Using small animal PET and ex vivo autoradiography, we examined the influence of pentobarbital and isoflurane anaesthesia on the rat brain uptake of [(18)F]MK-9470, a radioligand for the type 1 cannabinoid receptor. METHODS: PET imaging was performed on adult Wistar rats under pentobarbital (n = 6) and isoflurane anaesthesia (n = 7), and under control conditions (free moving during tracer uptake, n = 8). Parametric PET images were generated, anatomically standardized and analysed by voxel-based Statistical Parametric Mapping and a predefined volume of interest approach. Immediately after in vivo PET, brains were processed for ex vivo autoradiography using manually placed regions of interest. An extra group (n = 6) was included ex vivo, in which animals were intravenously injected without the use of anaesthetics. RESULTS: Using in vivo and ex vivo molecular imaging techniques, no significant changes in absolute [(18)F]MK-9470 uptake were present in the brain of pentobarbital and isoflurane rats as compared to control conditions. Relative [(18)F]MK-9470 uptake PET values obtained applying global scaling were, however, decreased in the cortex under both anaesthetics (pentobarbital: -13.3+/-1.4%; isoflurane -8.7 +/- 3.1%), while an increase was seen in the cerebellum by 13.5 +/- 4.0% and 13.9 +/- 4.1% under pentobarbital and isoflurane, respectively. Ex vivo results were in agreement with in vivo findings. CONCLUSION: These findings suggest a similar, regionally specific interference of pentobarbital and isoflurane anaesthesia with in vivo CB1 receptor imaging using [(18)F]MK-9470.sponsorship: The authors thank the Leuven PET radiopharmacy team for [18F]MK-9470 production and Merck & Co., Inc. for their availability of the [18F] MK-9470 precursor. Financial support of the Research Council of the Katholieke Universiteit Leuven (OT/05/58), the Fund for Scientific Research, Flanders, Belgium (FWO/G.0548.06) and the Institute for the Promotion of Innovation by Science and Technology in Flanders (SBO50151) is gratefully acknowledged. This work is also supported by MoSAIC, the K. U. Leuven Molecular Small Animal Imaging Center (KUL EF/05/08). KVL is a Senior Clinical Investigator of the Flemish Fund of Scientific Research. Part of this work is performed under the European Commission FP6 project Diagnostic Molecular Imaging (DIMI), LSHB-CT-2005-512146. (Research Council of the Katholieke Universiteit Leuven|OT/05/58, Fund for Scientific Research, Flanders, Belgium|FWO/G.0548.06, Institute for the Promotion of Innovation by Science and Technology in Flanders|SBO50151, MoSAIC, K. U. Leuven Molecular Small Animal Imaging Center|KUL EF/05/08, Flemish Fund of Scientific Research)status: Publishe
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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