Rifampicin pre-treatment inhibits the toxicity of rotenone-induced PC12 cells by enhancing sumoylation modification of α-synuclein

Our previous research revealed that rifampicin could protect PC12 (pheochromocytoma 12) cells from rotenone-induced cytotoxicity by reversing the aggregation of α-synuclein. Furthermore, increasing evidence indicated that the misfolded α-synuclein with SUMOylation, an important protein posttranslational modification, was easier to solubilize and was less toxic. Here, we investigated whether rifampicin could stabilize α-synuclein and prevent rotenone-induced PC12 cells from undergoing apoptosis by enhancing SUMOylation of α-synuclein. The expression of SUMO1 and SUMO2/3, the two main proteins responsible for the SUMOylation modification in PC12 cells, were detected by western blotting. Co-immunoprecipitation was performed to compare qualitatively the SUMOylation modification of α-synuclein. The cell viability and apoptosis rate were measured by a CCK-8 assay kit and flow cytometry, respectively. We targeted Ubc9 as a key enzyme in the SUMOylation modification pathway and knocked down the UBC9 gene using a short interfering RNA. Treatment with 150 μmol/L rifampicin, increased the expressions of SUMO1 and SUMO2/3 in cells by 1.5 times compared with the control group; meanwhile, the cell viability of rotenone-induced cells increased from 20 to 80% (P < 0.05). In addition, the increased SUMOylation activity in the cells stimulated by rifampicin was observed 18 h earlier compared with cells treated by rotenone alone. SUMOylation of α-synuclein was more significant in rifampicin-treated cells and Ubc9 upregulated cells. However, the same phenomenon and the protective effect of rifampicin were reversed after UBC9 knockout. In conclusion, rifampicin might reduce the cytotoxicity of rotenone-induced PC12 cells by promoting SUMOylation of α-synuclein.

Gliocyte and synapse analyses in cerebral ganglia of the Chinese mitten crab, Eriocheir sinensis: ultrastructural study

The Chinese mitten crab Eriocheir sinensis is an economically important aquatic species in China. Many studies on gene structure, breeding, and diseases of the crab have been reported. However, knowledge about the organization of the nerve system of the crab remains largely unknown. To study the ultrastructure of the cerebral ganglia of E. sinensis and to compare the histological findings regarding the nerve systems of crustaceans, the cerebral ganglia were observed by transmission electron microscopy. The results showed that four types of gliocytes, including type I, II, III, and IV gliocytes were located in the cerebral ganglia. In addition, three types of synapses were present in the cerebral ganglia, including unidirectional synapses, bidirectional synapses, and combined type synapses.

[The role of word recognition score in outcomes assessmentof idiopathic sudden sensorineural hearing loss]

Objective:To investigate the change of word recognition score(WRS) during the treatment of patients with idiopathic sudden sensorineural hearing loss(ISSNHL) and explore the role of WRS in outcomes assessment of ISSNHL.Method:Thirty-seven patients diagnosed with ISSNHL,whose pure-tone average(PTA) has no change but WRS has improved after treatment,were analyzed retrospectively.The WRS and the test intensity for WRS of pre-treatment and those of post-treatment were compared statistically.Result:There is statistical significance between WRS of post-treatment and that of pre-treatment(P<0.01).The increase of WRS score is consistent with improvement of symptom in these patients.Conclusion:More attention needs to be paid to WRS during treatment of ISSNHL patients,especially those whose PTA has no improvement but patients feel better about their hearing,and WRS could be an important factor in terms of outcome assessment during treatment of ISSNHL patients for the further treatment.

Post-translational modifications as key regulators of TNF-induced necroptosis

Necroptosis is a novel form of programmed cell death that is independent of caspase activity. Different stimuli can trigger necroptosis. At present, the most informative studies about necroptosis derive from the tumor necrosis factor (TNF)-triggered system. The initiation of TNF-induced necroptosis requires the kinase activity of receptor-interacting protein 1 and 3 (RIP1 and RIP3). Evidence now reveals that the ability of RIP1 and RIP3 to modulate this key cellular event is tightly controlled by post-translational modifications, including ubiquitination, phosphorylation, caspase 8-mediated cleavage and GlcNAcylation. These regulatory events coordinately determine whether a cell will survive or die by apoptosis or necroptosis. In this review, we highlight recent advances in the study of post-translational modifications during TNF-induced necroptosis and discuss how these modifications regulate the complex and delicate control of programmed necrosis.

Reproducibility of a Parkinsonism-related metabolic brain network in non-human primates: A descriptive pilot study with FDG PET

BACKGROUND

We have previously defined a parkinsonism-related metabolic brain network in rhesus macaques using a high-resolution research positron emission tomography camera. This brief article reports a descriptive pilot study to assess the reproducibility of network activity and regional glucose metabolism in independent parkinsonian macaques using a clinical positron emission tomography/CT camera.

METHODS

[(18)F]fluorodeoxyglucose PET scans were acquired longitudinally over 3 months in three drug-naïve parkinsonian and three healthy control cynomolgus macaques. Group difference and test-retest stability in network activity and regional glucose metabolism were evaluated graphically, using all brain images from these macaques.

RESULTS

Comparing the parkinsonian macaques with the controls, network activity was elevated and remained stable over 3 months. Normalized glucose metabolism increased in putamen/globus pallidus and sensorimotor regions but decreased in posterior parietal cortices.

CONCLUSIONS

Parkinsonism-related network activity can be reliably quantified in different macaques with a clinical positron emission tomography/CT scanner and is reproducible over a period typically employed in preclinical intervention studies. This measure can be a useful biomarker of disease process or drug effects in primate models of Parkinson's disease.

Parkinson's disease-related network topographies characterized with resting state functional MRI

Spatial covariance mapping can be used to identify and measure the activity of disease-related functional brain networks. While this approach has been widely used in the analysis of cerebral blood flow and metabolic PET scans, it is not clear whether it can be reliably applied to resting state functional MRI (rs-fMRI) data. In this study, we present a novel method based on independent component analysis (ICA) to characterize specific network topographies associated with Parkinson's disease (PD). Using rs-fMRI data from PD and healthy subjects, we used ICA with bootstrap resampling to identify a PD-related pattern that reliably discriminated the two groups. This topography, termed rs-MRI PD-related pattern (fPDRP), was similar to previously characterized disease-related patterns identified using metabolic PET imaging. Following pattern identification, we validated the fPDRP by computing its expression in rs-fMRI testing data on a prospective case basis. Indeed, significant increases in fPDRP expression were found in separate sets of PD and control subjects. In addition to providing a similar degree of group separation as PET, fPDRP values correlated with motor disability and declined toward normal with levodopa administration. Finally, we used this approach in conjunction with neuropsychological performance measures to identify a separate PD cognition-related pattern in the patients. This pattern, termed rs-fMRI PD cognition-related pattern (fPDCP), was topographically similar to its PET-derived counterpart. Subject scores for the fPDCP correlated with executive function in both training and testing data. These findings suggest that ICA can be used in conjunction with bootstrap resampling to identify and validate stable disease-related network topographies in rs-fMRI. Hum Brain Mapp 38:617-630, 2017. © 2016 Wiley Periodicals, Inc.

Predictors of proton pump inhibitor failure in non-erosive reflux disease: A study with impedance-pH monitoring and high-resolution manometry

BACKGROUND

Approximately one-third of gastroesophageal reflux disease (GERD) patients have symptoms resistant to proton pump inhibitor (PPI). We used the high-resolution manometry (HRM) and multichannel intraluminal impedance-pH (MII-pH) monitoring to investigate potential predictors of PPI failure in non-erosive reflux disease (NERD) patients.

METHODS

One hundred and seventeen NERD patients were included, within which there were 44 PPI failure patients. The symptomatic questionnaire GerdQ, HRM and 24-hour MII-pH monitoring were performed before PPI therapy. PPI failure was defined as persistent reflux symptoms for more than 1 day during the last week on esomeprazole (20 mg twice daily) for continuous 4 weeks. The predictors for PPI failure were investigated by multivariable logistic regression analysis.

KEY RESULTS

Proton pump inhibitor failure patients had lower body mass index (BMI) and more concomitant functional dyspepsia (FD) symptoms. PPI failure patients had a higher percentage of type I esophagogastric junction (EGJ) morphology (p = 0.005), increased EGJ augmentation (p = 0.000), higher prevalence of esophageal motility disorders (p = 0.005) and a higher ratio of negative symptom index (SI, p = 0.000). Multivariable regression analysis showed that concomitance of FD symptoms, EGJ augmentation and negative SI were independent risk factors for PPI failure in NERD.

CONCLUSIONS & INFERENCES

Approximately half of PPI failure patients were found to have esophageal motility disorders in HRM. The independent risk factors for PPI failure in NERD were concomitant FD symptoms, increased EGJ augmentation and negative SI.

Modulation of Abnormal Metabolic Brain Networks by Experimental Therapies in a Nonhuman Primate Model of Parkinson Disease: An Application to Human Retinal Pigment Epithelial Cell Implantation

Abnormal covariance pattern of regional metabolism associated with Parkinson disease (PD) is modulated by dopaminergic pharmacotherapy. Using high-resolution ¹⁸F-FDG PET and network analysis, we previously derived and validated a parkinsonism-related metabolic pattern (PRP) in nonhuman primate models of PD. It is currently not known whether this network is modulated by experimental therapeutics. In this study, we examined changes in network activity by striatal implantation of human levodopa-producing retinal pigment epithelial (hRPE) cells in parkinsonian macaques and evaluated the reproducibility of network activity in a small test-retest study.

METHODS

¹⁸F-FDG PET scans were acquired in 8 healthy macaques and 8 macaques with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced bilateral nigrostriatal dopaminergic lesions after unilateral putaminal implantation of hRPE cells or sham surgery. PRP activity was measured prospectively in all animals and in a subset of test-retest animals using a network quantification approach. Network activity and regional metabolic values were compared on a hemispheric basis between animal groups and treatment conditions.

RESULTS

All individual macaques showed clinical improvement after hRPE cell implantation compared with the sham surgery. PRP activity was elevated in the untreated MPTP hemispheres relative to those of the normal controls (P < 0.00005) but was reduced (P < 0.05) in the hRPE-implanted hemispheres. The modulation observed in network activity was supported by concurrent local and remote changes in regional glucose metabolism. PRP activity remained unchanged in the untreated MPTP hemispheres versus the sham-operated hemispheres. PRP activity was also stable (P ≥ 0.29) and correlated (R² ≥ 0.926; P < 0.00005) in the test-retest hemispheres. These findings were highly reproducible across several PRP topographies generated in multiple cohorts of parkinsonian and healthy macaques.

CONCLUSION

We have demonstrated long-term therapeutic effects of hRPE cell implantation in nonhuman primate models of PD. The implantation of such levodopa-producing cells can concurrently decrease the elevated metabolic network activity in parkinsonian brains on an individual basis. These results parallel the analogous findings reported in patients with PD undergoing levodopa therapy and other symptomatic interventions. With further validation in large samples, ¹⁸F-FDG PET imaging with network analysis may provide a viable biomarker for assessing treatment response in animal models of PD after experimental therapies.

Simultaneous quantification of hyperin, reynoutrin and guaijaverin in mice plasma by LC-MS/MS: application to a pharmacokinetic study

A specific and sensitive LC-MS/MS assay was developed to simultaneously quantify three structurally similar flavonoid glycosides - hyperin, reynoutrin and guaijaverin - in mouse plasma. Biosamples were prepared by solid-phase extraction. Isocratic chromatographic separation was performed on an AichromBond-AQ C18 column (250 × 2.1 mm, 5 μm) with methanol-acetonitrile-water-formic acid (20:25:55:0.1) as the mobile phase. Detection of hyperin, reynoutrin, guaijaverin and internal standard [luteolin-7-O-β-d-apiofuranosyl-(1 → 6)-β-d-glucopyranoside] was achieved by ESI-MS/MS in the negative ion mode using m/z 463 → m/z 300, m/z 433 → m/z 300, m/z 433 → m/z 300 and m/z 579 → m/z 285 transitions, respectively. Linear concentration ranges of calibration curves were 4.0-800.0 ng/mL for hyperin and reynoutrin and 8.0-1600.0 ng/mL for guaijaverin when 100 μL of plasma was analyzed. We used this validated method to study the pharmacokinetics of hyperin, reynoutrin and guaijaverin in mice following oral and intravenous administration. All three quercetin-3-O-glycosides showed poor oral absorption in mice, and the absolute bioavailability of hyperin after oral administration of 100 mg/kg was 1.2%. Pretreatment with verapamil increased the peak concentration and area under the concentration-time curve of hyperin, which were significantly higher than the control values. The half-life of hyperin with verapamil was significantly prolonged compared with that of the control. Copyright © 2016 John Wiley & Sons, Ltd.

Abnormal subchondral bone microstructure following steroid administration is involved in the early pathogenesis of steroid-induced osteonecrosis

Loss of bone microstructure integrity is thought to be related to osteonecrosis. But the relationship between the time when bone microstructure integrity loss appears and the onset of osteonecrosis has not yet been determined. Our study demonstrated abnormal changes of subchondral bone microstructure involved in the early pathogenesis of osteonecrosis.

INTRODUCTION

Using a rabbit model, we investigated the changes of subchondral bone microstructure following steroid administration to identify the onset of abnormal bone microstructure development in steroid-induced osteonecrosis.

METHODS

Fifty-five adult female Japanese White rabbits (mean body weight 3.5 kg; mean age 24 months) were used and randomly divided among three time points (3, 7, and 14 days) consisting of 15 rabbits each, received a single intramuscular injection of methylprednisolone acetate (MP; Pfizer Manufacturing Belgium NV) at a dose of 4 mg/kg, and a control group consisting of 10 rabbits was fed and housed under identical conditions but were not given steroid injections. A micro-CT scanner was applied to detect changes in the trabecular region of subchondral bone of excised femoral head samples. Parameters including bone volume fraction (BV/TV), bone surface (BS), trabecular bone pattern factor (Tb.Pf), trabecular thickness/number/separation (Tb.Th, Tb.N, and Tb.Sp), and structure model index (SMI) were evaluated using the software CTAn (SkyScan). After micro-CT scans, bilateral femoral heads were cut in the coronal plane at a thickness of 4 μm. The sections were then stained with haematoxylin-eosin and used for the diagnosis of osteonecrosis and the rate of development of osteonecrosis.

RESULTS

The BV/TV, BS, Tb.Th and Tb.N demonstrated a time-dependent decline from 3, 7, and 14 days compared with the control group, while the Tb.Pf, Tb.Sp and SMI demonstrated an increase at 3, 7, and 14 days compared with the control group. For the histopathology portion, osteonecrosis was not seen 3 days after steroid treatment, but was present 7 days after treatment and was obvious 14 days after treatment. Furthermore, the rate of osteonecrosis appearing between 7 and 14 days was not significantly different. In addition, the presence and variation of BV/TV, BS, Tb.Pf, Tb.Th, Tb.N, and SMI demonstrated significant changes at 7 days compared with the control group except Tb.Sp (at 14 days) and this is the time when osteonecrosis is thought to occur in this model.

CONCLUSION

This study demonstrated that osteonecrosis in rabbits is chronologically associated with changes in subchondral bone microstructure.

A simplified, data-constrained approach to estimate the permafrost carbon-climate feedback

We present an approach to estimate the feedback from large-scale thawing of permafrost soils using a simplified, data-constrained model that combines three elements: soil carbon (C) maps and profiles to identify the distribution and type of C in permafrost soils; incubation experiments to quantify the rates of C lost after thaw; and models of soil thermal dynamics in response to climate warming. We call the approach the Permafrost Carbon Network Incubation-Panarctic Thermal scaling approach (PInc-PanTher). The approach assumes that C stocks do not decompose at all when frozen, but once thawed follow set decomposition trajectories as a function of soil temperature. The trajectories are determined according to a three-pool decomposition model fitted to incubation data using parameters specific to soil horizon types. We calculate litterfall C inputs required to maintain steady-state C balance for the current climate, and hold those inputs constant. Soil temperatures are taken from the soil thermal modules of ecosystem model simulations forced by a common set of future climate change anomalies under two warming scenarios over the period 2010 to 2100. Under a medium warming scenario (RCP4.5), the approach projects permafrost soil C losses of 12.2-33.4 Pg C; under a high warming scenario (RCP8.5), the approach projects C losses of 27.9-112.6 Pg C. Projected C losses are roughly linearly proportional to global temperature changes across the two scenarios. These results indicate a global sensitivity of frozen soil C to climate change (γ sensitivity) of -14 to -19 Pg C °C(-1) on a 100 year time scale. For CH4 emissions, our approach assumes a fixed saturated area and that increases in CH4 emissions are related to increased heterotrophic respiration in anoxic soil, yielding CH4 emission increases of 7% and 35% for the RCP4.5 and RCP8.5 scenarios, respectively, which add an additional greenhouse gas forcing of approximately 10-18%. The simplified approach presented here neglects many important processes that may amplify or mitigate C release from permafrost soils, but serves as a data-constrained estimate on the forced, large-scale permafrost C response to warming.

Assessing cerebral glucose metabolism in patients with idiopathic rapid eye movement sleep behavior disorder

Correction to: Journal of Cerebral Blood Flow and Metabolism advance online publication, 29 July 2015; doi:10.1038/jcbfm.2015.173.

Following the online publication of this article, the authors noted that the order of the appearance of affiliations and the information of the correspondence were placed incorrectly. The affiliations of the authors and the order of the correspondence have been reordered as follows:

Jingjie Ge2,4, Ping Wu2,4, Shichun Peng3, Huan Yu1, Huiwei Zhang2, Yihui Guan2, David Eidelberg3, Chuantao Zuo2, Yilong Ma3,5, Jian Wang1,5

1Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China; 2PET Center, Huashan Hospital, Fudan University, Shanghai, China and 3Center for Neurosciences, The Feinstein Institute for Medical Research, North Shore-Long Island Jewish Health System, Manhasset, New York, USA.

Correspondence: Dr J Wang, Department of Neurology, Huashan Hospital, Fudan University, No. 12 Middle Wulumuqi Road, Jing'an District, Shanghai 200040, China or Dr Y Ma, Center for Neurosciences, The Feinstein Institute for Medical Research, 350 Community Drive, Manhasset, New York 11030, USA.

4These authors contributed equally to this work.

5These authors shared senior authorship.

E-mail: wangjian336@hotmail.com or yma@nshs.edu

Heterogeneous vesicles in mucous epithelial cells of posterior esophagus of Chinese giant salamander (Andrias davidianus)

The Chinese giant salamander belongs to an old lineage of salamanders and endangered species. Many studies of breeding and disease regarding this amphibian had been implemented. However, the studies on the ultrastructure of this amphibian are rare. In this work, we provide a histological and ultra-structural investigation on posterior esophagus of Chinese giant salamander. The sections of amphibian esophagus were stained by hematoxylin & eosin (H&E). Moreover, the esophageal epithelium was observed by transmission electron microscopy (TEM). The results showed that esophageal epithelium was a single layer epithelium, which consisted of mucous cells and columnar cells. The esophageal glands were present in submucosa. The columnar cells were ciliated. According to the diverging ultrastructure of mucous vesicles, three types of mucous cells could be identified in the esophageal mucosa: i) electron-lucent vesicles mucous cell (ELV-MC); ii) electron-dense vesicles mucous cell (EDV-MC); and iii) mixed vesicles mucous cell (MV-MC).

Has racial difference in cause-specific death improved in older patients with late-stage breast cancer?

BACKGROUND

Research on temporal mortality trends for stage IV breast cancer is limited, especially among older patients by race. We evaluated factors associated with overall, breast cancer-specific and other-cause mortalities using contemporary population data.

PATIENTS AND METHODS

Using the Surveillance, Epidemiology, and End Results-Medicare linked data, we identified older women (≥ 66 years) with stage IV breast cancer diagnosed in 2002-2009. Overall mortality was estimated by the Kaplan-Meier method, compared by log-rank tests, and modeled by Cox models. Competing risk analysis was used to evaluate breast cancer-specific and other-cause mortalities.

RESULTS

The median overall survival time for non-Hispanic blacks improved from 8.6 months in 2002-2003 to 9.9 months in 2007-2009, whereas that for non-Hispanic whites improved from 12.1 to 14.8 months. In the multivariate model, the risk of breast cancer-specific death for patients diagnosed in 2007-2009 was significantly lower (P = 0.02), whereas the risk of other-cause mortality changed little (P = 0.88) compared with those risks for patients diagnosed in 2002-2003. Non-Hispanic blacks had the higher risk of both mortality types compared with non-Hispanic whites; a diagnosis time-race interaction term was not statistically significant for either cause of death.

CONCLUSION

Breast cancer-specific mortality among older women modestly improved from 2002 to 2009 across all races, but not other-cause mortality. Racial disparity in mortality persisted, but did not widen in this period. Efforts should be devoted to improving other-cause mortality for all women, with special attention toward decreasing breast cancer mortality for non-Hispanic black women.

TRAF3IP3, a novel autophagy up-regulated gene, is involved in marginal zone B lymphocyte development and survival

Tumour necrosis factor receptor-associated factor 3 (TRAF3) interacting protein 3 (TRAF3IP3; also known as T3JAM) is expressed specifically in immune organs and tissues. To investigate the impact of TRAF3IP3 on immunity, we generated Traf3ip3 knock-out (KO) mice. Interestingly, these mice exhibited a significant reduction in the number of common lymphoid progenitors (CLPs) and inhibition of B cell development in the bone marrow. Furthermore, Traf3ip3 KO mice lacked marginal zone (MZ) B cells in the spleen. Traf3ip3 KO mice also exhibited a reduced amount of serum natural antibodies and impaired T cell-independent type II (TI-II) responses to trinitrophenol (TNP)-Ficoll antigen. Additionally, our results showed that Traf3ip3 promotes autophagy via an ATG16L1-binding motif, and MZ B cells isolated from mutant mice showed a diminished level of autophagy and a high rate of apoptosis. These results suggest that TRAF3IP3 contributes to MZ B cell survival by up-regulating autophagy, thereby promoting the TI-II immune response.

Intravaginal HPV DNA vaccination with electroporation induces local CD8+ T-cell immune responses and antitumor effects against cervicovaginal tumors

Therapeutic human papillomavirus (HPV) vaccines have the potential to inhibit the progression of an established HPV infection to precancer and cancer lesions by targeting HPV oncoproteins. We have previously developed a therapeutic DNA vaccine encoding calreticulin (CRT) linked to E7, CRT/E7 DNA vaccine, for use in the treatment of HPV-associated lesions. Since the transfection efficiency of DNA vaccines administered in vivo is typically low, we examined the use of electroporation as well as different routes of administration to enhance antigen-specific tumor control. We tested the effects of the CRT/E7 DNA vaccine administered intramuscularly or intravaginally, with or without electroporation, on the generation of CD8+ T-cell immunity and therapeutic antitumor effects in HPV16 E7-expressing cervicovaginal tumor-bearing mice. We found that intravaginal vaccination of CRT/E7 DNA followed by electroporation-induced potent E7-specific CD8(+) T-cell responses in the cervicovaginal tract, compared with intramuscular injection followed by electroporation. Furthermore, tumor-bearing mice vaccinated intravaginally followed by electroporation had an enhanced survival, antitumor effects and local production of IFN-γ+CD8+ T cells compared with those vaccinated intramuscularly with electroporation. Thus, we show that intravaginal CRT/E7 DNA vaccination followed by electroporation generates the most potent therapeutic antitumor effects against an orthotopic E7-expressing tumor model. The current study will have significant clinical implications once a clinically applicable electroporation device for intravaginal use becomes available.

Dopaminergic correlates of metabolic network activity in Parkinson's disease

Parkinson's disease (PD) is associated with distinct metabolic covariance patterns that relate to the motor and cognitive manifestations of the disorder. It is not known, however, how the expression of these patterns relates to measurements of nigrostriatal dopaminergic activity from the same individuals. To explore these associations, we studied 106 PD subjects who underwent cerebral PET with both (18) F-fluorodeoxyglucose (FDG) and (18) F-fluoro-L-dopa (FDOPA). Expression values for the PD motor- and cognition-related metabolic patterns (PDRP and PDCP, respectively) were computed for each subject; these measures were correlated with FDOPA uptake on a voxel-by-voxel basis. To explore the relationship between dopaminergic function and local metabolic activity, caudate and putamen FDOPA PET signal was correlated voxel-wise with FDG uptake over the entire brain. PDRP expression correlated with FDOPA uptake in caudate and putamen (P < 0.001), while PDCP expression correlated with uptake in the anterior striatum (P < 0.001). While statistically significant, the correlations were only of modest size, accounting for less than 20% of the overall variation in these measures. After controlling for PDCP expression, PDRP correlations were significant only in the posterior putamen. Of note, voxel-wise correlations between caudate/putamen FDOPA uptake and whole-brain FDG uptake were significant almost exclusively in PDRP regions. Overall, the data indicate that PDRP and PDCP expression correlates significantly with PET indices of presynaptic dopaminergic functioning obtained in the same individuals. Even so, the modest size of these correlations suggests that in PD patients, individual differences in network activity cannot be explained solely by nigrostriatal dopamine loss.