White matter hyperintensities mediate the impact of amyloid ß on future freezing of gait in Parkinson's disease

BackgroundFreezing of gait (FOG) is a common symptom in Parkinson's Disease (PD) patients. Previous studies have reported relationships between FOG, substantia nigra (SN) degeneration, dopamine transporter (DAT) concentration, as well as amyloid β deposition. However, there is a paucity of research on the concurrent impact of white matter damage.ObjectivesTo assess the inter-relationships between these different co-morbidities, their impact on future FOG and whether they act independently of each other.MethodsWe used baseline MRI and longitudinal gait data from 423 de novo PD patients from the Parkinson's Progression Markers Initiative (PPMI). We used deformation based morphometry (DBM) from T1-weighted MRI to measure SN atrophy, and segmentation of white matter hyperintensities (WMH) as a measure of WM pathological load. Putamen and caudate DAT levels from SPECT as well as cerebrospinal fluid (CSF) amyloid β were obtained directly from the PPMI. Following correlation analyses, we investigated whether WMH burden mediates the impact of amyloid β on future FOG.ResultsSN DBM, WMH load, putamen and caudate DAT activity and CSF amyloid β levels were significantly different between PD patients with and without future FOG (p < 0.008). Mediation analysis demonstrated an effect of CSF amyloid β levels on future FOG via WMH load, independent of SN atrophy and striatal DAT activity levels.ConclusionsAmyloid β might impact future FOG in PD patients through an increase in WMH burden, in a pathway independent of Lewy body pathology.     

Magnetic resonance imaging accurately tracks kidney pathology and heterogeneity in the transition from acute kidney injury to chronic kidney disease

1. Download : Download high-res image (366KB)
2. Download : Download full-size image

     

Peroperative scoring systems for predicting the outcome of cytoreductive surgery in advanced-stage ovarian cancer – A systematic review

The extent of peritoneal metastases (PM) largely determines the possibility of complete or optimal cytoreductive surgery in advanced ovarian cancer. An objective scoring system to quantify the extent of PM can help clinicians to decide whether or not to embark on CRS. Therefore several scoring systems have been developed by different research teams and this review summarizes their performance in predicting a complete or optimal cytoreduction in patients with advanced ovarian cancer. A systematic search in the MEDLINE database revealed 19 articles that described a total of five main scoring systems to predict the completeness of CRS in patients with FIGO stage III-IV ovarian cancer based on the surgical exploration of the abdominal cavity; PCI, PIV, Eisenkop, Espada, and Kasper. The Peritoneal Cancer Index (PCI) and the Predictive Index Value (PIV) were mentioned most frequently and showed AUCs of 0.69–0.92 and 0.66–0.98, respectively. Due to the use of different cut-offs sensitivities and specificities greatly varied. Therefore with the current data, no scoring system could be identified as best. An objective measure of the extent of disease can be of great clinical use for identifying ovarian cancer patients for which a complete (or optimal) CRS is achievable, however due to local differences in treatment strategies and surgical policy a widely adopted objective scoring system with a standard cut-off value is not feasible. Nevertheless, objective scoring systems can play an important role to guide treatment decisions.