AbstractHuman embryonic stem cells (hESCs) differentiate into specialized cells, including midbrain dopaminergic neurons (DAN). Non-human primates (NHPs) injected with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine develop some alterations observed in Parkinson’s disease (PD) patients. We obtained DAN from hESCs and confirmed that they express dopaminergic markers, generate action potentials, and release dopamine (DA) in vitro. DAN were transplanted bilaterally in the putamen of parkinsonian NHPs. After grafting, animals improved motor behavior, evaluated by the HALLWAY task, and in agreement with this recovery, DA release was detected by microdialysis. Imaging techniques revealed changes in fractional anisotropy and mean diffusivity in magnetic resonance imaging and higher 11C-DTBZ binding in positron-emission tomography scans, associated with grafts. Postmortem analysis showed that transplanted DAN survived over ten months in the putamen, without developing tumors, in the immunosuppressed NHPs. These results indicate that cell replacement therapy with hESCs-derived DAN causes long-term biochemical, anatomical, and physiological improvements in this model of PD.
Background: The use of single-photon emission computed tomography and positron emission tomography (PET) has proven to be helpful in differentiating Parkinson's disease (PD) from other movement disorders with a sensitivity of up to 95%. Objective: The objective of this study was to determine the accuracy of [ 11 C]DTBZ PET imaging in patients with clinically uncertain parkinsonism from a tertiary referral center in Mexico City. Materials and Methods: Patients who underwent [ 11 C]DTBZ PET brain scan due to clinically uncertain parkinsonism where divided into two groups: PD or non-PD. A scan was considered positive when visual assessment revealed a decrease in [ 11 C]DTBZ uptake typical for PD; a scan was considered negative when visual assessment showed no decrease in [ 11 C]DTBZ uptake or showed a decrease in tracer uptake in a non-PD pattern. Sensitivity, specificity, and positive and negative predictive values were calculated using a 2 × 2 table, with a 95% confidence interval. Results: A total of 39 patients were included in the study. 14 PET studies were deemed positive and 25 PET studies were deemed negative; 12 true positives and 23 true negatives were found. This yielded a sensitivity of 92.9% (95% CI, 66.1-99.8),
The current study describes the case of a woman with symptomatic epilepsy due to brain cysticercosis acquired during childhood. During her adolescence, she developed seizures characterized by metamorphopsia, hallucinations of autobiographic memory and, finally, asomatognosia. Magnetic brain imaging showed a calcified lesion in the right occipitotemporal cortex, and positron emission tomography imaging confirmed the presence of interictal hypometabolism in two regions: the right parietal cortex and the right lateral and posterior temporal cortex. We discuss the link between these brain areas and the symptoms described under the concepts of epileptogenic lesion, epileptogenic zone, functional deficit zone, and symptomatogenic zone.
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