Differentiation of dementia with Lewy bodies from Alzheimer's disease using a dopaminergic presynaptic ligand

Background: Dementia with Lewy bodies (DLB) is one of the main differential diagnoses of Alzheimer's disease (AD). Key pathological features of patients with DLB are not only the presence of cerebral cortical neuronal loss, with Lewy bodies in surviving neurones, but also loss of nigrostriatal dopaminergic neurones, similar to that of Parkinson's disease (PD). In DLB there is 40-70% loss of striatal dopamine.Objective: To determine if detection of this dopaminergic degeneration can help to distinguish DLB from AD during life.Methods: The integrity of the nigrostriatal metabolism in 27 patients with DLB, 17 with AD, 19 drug naive patients with PD, and 16 controls was assessed using a dopaminergic presynaptic ligand, I-123-labelled 2beta-carbomethoxy-3beta-(4-iodophenyl)-N-(3-fluoropropyl)nortropane (FP-CIT), and single photon emission tomography (SPET). A SPET scan was carried out with a single slice, brain dedicated tomograph (SME 810) 3.5 hours after intravenous injection of 185 MBq FP-CIT. With occipital cortex used as a radioactivity uptake reference, ratios for the caudate nucleus and the anterior and posterior putamen of both hemispheres were calculated. All scans were also rated by a simple visual method.Results: Both DLB and PD patients had significantly lower uptake of radioactivity than patients with (p<0.01) and controls (p<0.001) in the caudate nucleus and the anterior and posterior Putamen.Conclusion: FP-CIT SPET provides a means of distinguishing DLB from AD during life

Nmda Glutamatergic Receptors, Labeled With [h-3] Mk-801, in Brain Samples From Drug-free Depressed Suicides

Glutamate receptors of the NMDA-subtype were quantitated by binding of [H-3]dizocilpine maleate (MK-801) in nine brain regions from 22 suicide victims (20-60 yr), with a firm retrospective diagnosis of depression, who had not recently received antidepressant drugs, and 20 age- and sex-matched controls. [H-3]MK-801-binding did not differ between suicides and controls in any region studied. Suicides who died violently did not differ from non-violent suicides and controls. A significative negative correlation was found between age and NMDA receptor-binding in the frontal cortex of suicide victims, but not in controls. This preliminary study provides little evidence for an important role of NMDA-binding sites in the pathophysiology of depression

Olanzapine in dementia with Lewy bodies: A clinical study

Objectives. Dementia with Lewy bodies (DLB) is now a well-recognized form of dementia in which psychosis and behavioural disturbance are common. Treatment with conventional neuroleptics is often very poorly tolerated. Olanzapine, a newly introduced atypical neuroleptic which binds to multiple receptor types with relatively low affinity for D2 receptors, may be a useful treatment option in DLB. Main outcome measures. The Behavioural Pathology in Alzheimer\u27s Disease Rating Scale, The Neuropsychiatric Inventory, Unified Parkinson\u27s Disease Rating Scale and The Webster Disability Scale. Design. We present the results of eight DLB patients with associated psychotic and behavioural difficulties. All patients were given olanzapine 2.5-7.5 mg. Their psychotic phenomena and behavioural and extrapyramidal symptoms were monitored at 2-weekly intervals. Results. Three out of the eight patients could not tolerate olanzapine even at the lowest available dose. Two patients had clear improvement in psychotic and behavioural symptoms. Three patients were able to tolerate olanzapine but gained only minimal benefit. Conclusions. Olanzapine at the doses used conferred little advantage over conventional neuroleptics and should only be given with great caution to patients with DLB. The utility of smaller doses deserves further evaluation