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排序方式: 共有335条查询结果,搜索用时 31 毫秒
1.
Daniel P. Holt Hayden T. Ravert Robert F. Dannals 《Journal of labelled compounds & radiopharmaceuticals》2016,59(10):411-415
The detailed synthesis and quality control of [18F]T807, radiotracer for tau protein aggregate imaging, are described. The radiotracer synthesis was accomplished in an average of 48 min with an average specific activity at end‐of‐synthesis of over 4.4 TBq/µmole (120 Ci/µmole) and an average radiochemical yield of 32%. Compliance with all standard US Pharmacopeia Chapter <823> acceptance tests was observed. 相似文献
2.
Rashid Ghaznawi Maarten HT Zwartbol Nicolaas PA Zuithoff Jeroen de Bresser Jeroen Hendrikse Mirjam I Geerlings 《Journal of cerebral blood flow and metabolism》2021,41(6):1229
Global cerebral hypoperfusion may be involved in the aetiology of brain atrophy; however, long-term longitudinal studies on this relationship are lacking. We examined whether reduced cerebral blood flow was associated with greater progression of brain atrophy. Data of 1165 patients (61 ± 10 years) from the SMART-MR study, a prospective cohort study of patients with arterial disease, were used of whom 689 participated after 4 years and 297 again after 12 years. Attrition was substantial. Total brain volume and total cerebral blood flow were obtained from magnetic resonance imaging scans and expressed as brain parenchymal fraction (BPF) and parenchymal cerebral blood flow (pCBF). Mean decrease in BPF per year was 0.22% total intracranial volume (95% CI: –0.23 to –0.21). Mean decrease in pCBF per year was 0.24 ml/min per 100 ml brain volume (95% CI: –0.29 to –0.20). Using linear mixed models, lower pCBF at baseline was associated with a greater decrease in BPF over time (p = 0.01). Lower baseline BPF, however, was not associated with a greater decrease in pCBF (p = 0.43). These findings indicate that reduced cerebral blood flow is associated with greater progression of brain atrophy and provide further support for a role of cerebral blood flow in the process of neurodegeneration. 相似文献
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Duc T Quach Toru Hiyama Fumio Shimamoto Quang D Le Linh X Ho Nhu HT Vu Masaharu Yoshihara Naomi Uemura 《World journal of gastroenterology : WJG》2014,20(17):5087-5091
AIM:To assess the value of a new test for the diagnosis of Helicobacter pylori(H.pylori) infection,Rapirun H.pylori Antibody Stick(Rapirun Stick),in a Vietnamese population.METHODS:Eligible patients without previous history of H.pylori eradication were recruited.Rapid urease test(RUT) and histologic examination were used to diagnose the H.pylori infection.Patients were considered H.pylori positive when the RUT results were positive and/or the bacteria were detected histologically.Rapirun Stick tests were performed using urine samples,and the results were compared with the other 2 methods.RESULTS:We enrolled 200 patients with a mean age of 36(range,18-76) years.There were 116 females and 84 males.Of the 200 patients,111(55.5%) were diagnosed as being H.pylori positive.The sensitivity,specificity,and accuracy of the Stick test were 84.7%,89.9%,and 87.0%,respectively.There were 17(8.5%) falsenegative patients and 9(4.5%) false-positive patients.CONCLUSION:The Rapirun Stick test has high sensitivity,specificity,and accuracy for the diagnosis of H.pylori infection in the Vietnamese population.The test can be clinically applied in Vietnamese populations. 相似文献
7.
Review of the Lynch syndrome: history, molecular genetics, screening, differential diagnosis, and medicolegal ramifications 总被引:1,自引:0,他引:1
Platelets have a central role in the development of arterial thrombosis and subsequent cardiovascular events. An appreciation of this complex process has made antiplatelet therapy the cornerstone of cardiovascular disease management. However, numerous patients will experience a recurrent atherothrombotic vascular event despite adequate antiplatelet therapy. Individual differences in the rate of platelet activation and reactivity markedly influence normal hemostasis and the pathological outcome of thrombosis. Such an individual variability is largely determined by environmental and genetic factors. These are known to either hamper platelets' response to agonists, and thereby mimic the pharmacological modulation of platelet function or mask therapy effect and sensitize platelets. In this article, we reviewed the antiplatelet mechanisms of aspirin and clopidogrel and the possible role of different polymorphisms, which may affect the efficacy of antiplatelet therapy. Heterogeneity in the way patients respond to aspirin and clopidogrel may in part reflect variation in cyclooxygenase (COX)-1, COX-2, glycoprotein (GP) Ib alpha, GP Ia/IIa, GP IIb/IIIa, UGT1A6*2, P2Y1 , P2Y12 , CYP2C9, CYP3A4 and CYP3A5 genotypes. 相似文献
8.
H S Mayberg B Sadzot C C Meltzer R S Fisher R P Lesser R F Dannals J R Lever A A Wilson H T Ravert H N Wagner 《Annals of neurology》1991,30(1):3-11
Alterations in a variety of neurotransmitter systems have been identified in experimental models of epilepsy and in brain tissue from patients with intractable temporal lobe seizures. The availability of new high-affinity radioligands permits the study of some neuroreceptors in vivo with positron emission tomography (PET). We previously characterized the in vivo binding of 11C-carfentanil, a potent and selective mu opiate receptor agonist, and described increases in 11C-carfentanil binding in the temporal neocortex of patients with unilateral temporal lobe epilepsy. These studies have been extended to 11C-diprenorphine, which labels mu, kappa, and delta opiate receptor subtypes. Paired measurements of opiate receptor binding were performed with PET using 11C-carfentanil and 11C-diprenorphine in patients with unilateral temporal lobe seizures. Carfentanil binding, reflecting changes in mu opiate receptors, was increased in the temporal neocortex and decreased in the amygdala on the side of the epileptic focus. Diprenorphine binding, reflecting mu as well as non-mu opiate subtypes, was not significantly different among regions in the focus and nonfocus temporal lobes. Regional glucose metabolism, measured using 18F-2-fluoro-2-deoxyglucose, was decreased in the mesial and lateral aspects of the temporal lobe ipsilateral to the epileptogenic focus. The variation in pattern of carfentanil and diprenorphine binding supports a differential regulation of opiate subtypes in unilateral temporal lobe epilepsy. 相似文献
9.
Z Szabo U Scheffel W B Mathews H T Ravert K Szabo M Kraut S Palmon G A Ricaurte R F Dannals 《Journal of cerebral blood flow and metabolism》1999,19(9):967-981
The impulse response function of a radioligand is the most fundamental way to describe its pharmacokinetics and to assess its tissue uptake and retention pattern. This study investigates the impulse response function of [11C](+)McN5652, a radioligand used for positron emission tomography (PET) imaging of the serotonin transporter (SERT) in the brain. Dynamic PET studies were performed in eight healthy volunteers injected with [11C](+)McN5652 and subsequently with its pharmacologically inactive enantiomer [11C](-)McN5652. The impulse response function was calculated by deconvolution analysis of regional time-activity curves, and its peak value (f(max)), its retention value at 75 minutes (fT), and its normalized retention (f(rel) = fT/f(max)) were obtained. Alternatively, compartmental models were applied to calculate the apparent total distribution volume (DV(T)) and its specific binding component (DV(S)). Both the noncompartmental (fT,f(rel)) and the compartmental parameters (DV) were investigated with and without correction for nonspecific binding by simple subtraction of the corresponding value obtained with [11C](-)McN5652. The impulse response function obtained by deconvolution analysis demonstrated high tracer extraction followed by a slow decline in the form of a monoexponential function. Statistical analysis revealed that the best compartmental model in terms of analysis of variance F and condition number of the parameter variance-covariance matrix was the one that was based on a single tissue compartment with parameters k1 and k2 and that also included the parameter of regional cerebral blood volume (BV). The parameter f(rel) demonstrated low between-subject variance (coefficient of variation [CV] = 19%), a midbrain to cerebellum ratio of 1.85, and high correlation with the known density of SERT (r = 0.787 where r is the coefficient of linear correlation between the parameter and the known density of SERT). After correction for nonspecific binding, f(rel) demonstrated further improvement in correlation (r = 0.814) and midbrain to cerebellum ratio (3.09). The variance of the distribution volumes was acceptable when the logarithmic transform lnDV was used instead of DV (17% for the three-parameter model), but correlation of this compartmental parameter was slightly less (r = 0.652 for the three-parameter model) than the correlation of the noncompartmental f(rel) with the known density of SERT, and the midbrain to cerebellum ratio was only 1.5 (uncorrected) and 1.8 (corrected). At the expense of increasing variance, the correlation was increased after correction for nonspecific binding using the inactive enantiomer (r = 0.694; CV = 22%). These results indicate that the kinetics of [11C](+)McN5652 can best be described by a one-tissue compartment model with three parameters (k1, k2, and BV), and that both the noncompartmental parameter f(rel) and the compartmental distribution volumes have the potential for quantitative estimation of the density of SERT. Further validation of the radioligand in experimental and clinical situations is warranted. 相似文献
10.
Hayden T Ravert Ursula Scheffel William B Mathews John L Musachio Robert F Dannals 《Nuclear medicine and biology》2002,29(1):47-53
The R and S enantiomers of [(11)C]GR89696, [(11)C]-methyl 4-[(3,4-dichlorophenyl)acetyl]-3-[(1-pyrrolidinyl)methyl]-1-piperazinecarboxylate, were synthesized from their appropriate chiral precursors and [(11)C]methyl chloroformate. The [(11)C]-labeled R enantiomer of GR89696, also known as GR103545, demonstrated high affinity in mouse brain with region to cerebellar ratios at 90 minutes of 11.4 and 8.7 for the hypothalamus and olfactory tubercle, respectively. The [(11)C]-labeled S enantiomer showed low affinity and region to cerebellar ratios of 1 for all brain regions. The [(11)C]-labeled GR103545 exhibited a selective and saturable binding for the kappa opioid receptor. 相似文献