PubMed · 8595044
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A Pascual-Leone, J Grafman, M Hallett. 1995-12-15. Procedural learning and prefrontal cortex.. https://doi.org/10.1111/j.1749-6632.1995.tb38131.x
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Optimization of the procedures for neural grafting is a timely issue, as this technique has proven beneficial for a few patients with late-stage Parkinson's disease in pilot studies and therefore may expand to become a more widely available therapeutic. In this research, one major issue is that of the placement of the cell deposits in the right target areas within the striatum. Although it is widely accepted that these suitable regions are the sensorimotor regions of the putamen, reliable delineation of these areas using classical stereotactical mapping techniques remains difficult. Along the course of a 5-year-long clinical transplantation program, we have developed an original procedure based on magnetic resonance imaging of the striatum on parasagittal views. This technique allowed us to identify precisely, and reproducibly in each patient, three subregions of the putamen (precommissural, commissural, and postcommissural) to be implanted. On the basis of the literature defining the sensorimotor putaminal regions in nonhuman primates, it was subsequently possible to extrapolate and localize these regions in each patient, thus providing a basis for the placement of cell deposits. Examples taken from our series of grafted patients demonstrate the value of this procedure that, in addition, minimizes interference of interindividual variability in the interpretation of clinical results.
The neuropathological characteristics and alteration of the dopamine D2 receptor (D2R) were investigated in 27 cases of hypoxic-ischemic basal ganglia necrosis (BGN) by means of neuropathological and immunohistochemical methods. Perinatal hypoxic-ischemic BGN manifested neuronal karyorrhexis as well as eosinophilia, karyorrhexis being more predominant in preterm infants and eosinophilia more predominant in full-term infants. Immunoreactivity to D2R was detected in the cytoplasm and dendrites of small and large neurons in the basal ganglia, and increased with neuronal maturation during the late gestational period in normal human basal ganglia. The number of D2R-positive neurons was smaller in all cases of acute BGN than that in controls, the areas of decreased D2R-positive neurons corresponding to the damaged regions observed on HE staining. Furthermore, neurons showed high expression of D2R in a few cases of remote BGN, suggesting some plasticity as to the recovery of D2R. Thus, the neuropathological characteristics of perinatal hypoxic-ischemic BGN may be related to neuronal maturation during different developmental stages in each region, and D2R development may play a role in the basal ganglia vulnerability to hypoxic-ischemia.
BACKGROUND: As many as 20% of individuals with the clinical diagnosis of Parkinson's disease (PD) do not have the characteristic neuropathologic features of PD at post mortem. The striatonigral degeneration (SND) subtype of multiple system atrophy is one of the categories of pathology which may be incorrectly diagnosed as PD on the basis of clinical presentation. SND may be associated with increased iron deposition in the putamen which can be detected with magnetic resonance imaging. METHODS: We have estimated regional brain iron content in a patient with probable SND, using a novel imaging method developed in our laboratory, and have compared the results in this patient to those which we have previously reported in patients with PD and in age-matched controls. RESULTS: We observed that putamenal iron content was increased in our SND patient, beyond the 95% confidence limit for inclusion in the PD group, even when considering clinical severity. In contrast, pallidal and thalamic iron were within the PD range. CONCLUSIONS: The demonstration of increased putamenal iron content may be a useful adjunctive investigative procedure in patients with suspected SND.