Objective Nonmotor symptoms (NMS) are critical players in the patients' quality of life in Parkinson disease (PD). Vesicular monoamine transporter type 2 (VMAT2) has been reported owing to a role in affecting dopamine neurons in the striatum. Therefore, this study set out to characterize the relationship between VMAT2 distribution in the striatum in relation to the NMS in PD. Methods Totally, 21 age-matched normal controls and 37 patients with PD in the moderate stages were included, followed by examination using 18F-DTBZ (18F-AV133) PET/CT. The specific uptake ratio (SUR) of each striatal subregion was then determined with the occipital cortex as the reference background region. The overall NMSs of each individual patient were evaluated. Finally, the role of the striatal SURs in the clinical symptom scores were evaluated through the application of a Spearman correlation analysis as well as a multivariable stepwise regression analysis. Results Patients with PD, particularly those at a more advanced stage, exhibited a more pronounced reduction in SURs in the bilateral putamen and caudate nucleus (P < 0.05, vs healthy controls). Meanwhile, patients at more advanced PD stages were found to have significantly worse scores in NMS except cognitive function. The Spearman correlation analysis demonstrated that NMS scores, with the exception of cognition scores, were correlated with striatal SURs (P < 0.05). Conclusion The key findings of the study identified a correlation between decreased striatal VMAT2 with a broad spectrum of NMS in patients with PD, highlighting the association between diminished dopamine supply and the development of NMS in PD.
PurposeThe aim of the study was to evaluate the efficacy of 13N-ammonia and 18F-fluorodeoxyglucose (18F-FDG) PET performed on the same day in the detection of advanced prostate cancer (PC) and its metastases.Patients and methodsTwenty-six patients with high-risk PC [Gleason score 8–10 or prostate-specific antigen (PSA)>20 ng/ml or clinical tumor extension≥T2c] were recruited into the study. 13N-Ammonia and 18F-FDG PET/CT were performed on the same day (18F-FDG followed ammonia, with an interval of a minimum of 2 h). Lesions were interpreted as positive, negative, or equivocal. Patient-based and field-based performance characteristics for both imaging techniques were reported.ResultsThere was significant correlation between 13N-ammonia and 18F-FDG PET/CT in the detection of primary PC (κ=0.425, P=0.001) and no significant difference in sensitivity (60.2 vs. 54.5%) and specificity (100 vs. 83.3%). The maximum standard uptake values and corresponding target-to-background ratio values of the concordantly positive lesions in prostate glands in the two studies did not differ significantly (P=0.124 and 0.075, respectively). The sensitivity and specificity of PET imaging using 13N-ammonia for lymph node metastases were 77.5 and 96.3%, respectively, whereas the values were 75 and 44.4% using 18F-FDG. The two modalities were highly correlated with respect to the detection of lymph nodes and bone metastases.ConclusionThe concordance between the two imaging modalities suggests a clinical impact of 13N-ammonia PET/CT in advanced PC patients as well as of 18F-FDG. 13N-Ammonia is a useful PET tracer and a complement to 18F-FDG for detecting primary focus and distant metastases in PC. The combination of these two tracers on the same day can accurately detect advanced PC.
Background: The anticancer potential of pharmacologic ascorbic acid (AA) has been detected in a number of cancer cells. However, in vivo study suggested a strongly reduced cytotoxic activity of AA. It was known that pH could be a critical influencing factor for multiple anticancer treatments. In this study, we explored the influence of pH on the cytotoxicity of ascorbic acid. We employed castration-resistant prostate cancer (CRPC) cell lines PC3 and DU145 to observe the therapeutic effect of AA on PCa cells that were cultured with different pH in vitro. We also analyzed the influence of pH and extracellular oxidation on cytotoxicity of AA in cancer cells using reactive oxygen species (ROS) assay, cellular uptake of AA, and NADPH assay. Male BALB/c nude mice bearing prostate carcinoma xenografts (PC3 or DU145) were used to assess treatment response to AA with or without bicarbonate in vivo. The cellular uptake of AA in PCa xenografts was detected using positron emission tomography (PET). Small animal PET/CT scans were performed on mice after the administration of 6-deoxy-6-[ 18 F] fluoro-L-ascorbic acid (18 F-DFA). Results: Our in vitro studies demonstrate that acidic pH attenuates the cytotoxic activity of pharmacologic ascorbic acid by inhibiting AA uptake in PCa cells. Additionally, we found that the cancer cell-selective toxicity of AA depends on ROS. In vivo, combination of AA and bicarbonate could provide a significant better therapeutic outcome in comparison with controls or AA single treated mice. 18 F-DFA PET imaging illustrated that the treatment with NaHCO 3 could significantly increase the AA uptake in tumor. Conclusions: The alkalinity of tumor microenvironment plays an important role in anticancer efficiency of AA in CRPC. 18 F-DFA PET/CT imaging could predict the
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