In vivo positron emission tomographic evidence for compensatory changes in presynaptic dopaminergic nerve terminals in Parkinson's disease
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Clinical symptoms of Parkinson's disease (PD) do not manifest until dopamine (DA) neuronal loss reaches a symptomatic threshold. To explore the mechanisms of functional compensation that occur in presynaptic DA nerve terminals in PD, we compared striatal positron emission tomographic (PET) measurements by using [11C]dihydrotetrabenazine ([11C]DTBZ; labeling the vesicular monoamine transporter type 2), [11C]methylphenidate (labeling the plasma membrane DA transporter), and [18F]dopa (reflecting synthesis and storage of DA). Three consecutive PET scans were performed in three-dimensional mode by using each tracer on 35 patients and 16 age-matched, normal controls. PET measurements by the three tracers were compared between subgroups of earlier and later stages of PD, between drug-naive and drug-treated subgroups of PD, and between subregions of the parkinsonian striatum. The quantitative relationships of [18F]dopa and [11]DTBZ, and of [11C]methylphenidate and [11C]DTBZ, were compared between the PD and the normal control subjects. We found that [18F]dopa Ki was reduced less than the binding potential (Bmax/Kd) for [11C]DTBZ in the parkinsonian striatum, whereas the [11C]methylphenidate binding potential was reduced more than [11C]DTBZ binding potential. These observations suggest that the activity of aromatic L-amino acid decarboxylase is up-regulated, whereas the plasma membrane DA transporter is down-regulated in the striatum of patients with PD.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it