ro-16-0154 and Nerve-Degeneration

Iomazenil (IMZ) is a partial inverse agonist of central-type benzodiazepine receptors (BZR) which binds specifically to BZR with high affinity. A multi-center Phase 3 clinical study was performed to evaluate the clinical usefulness of 123I-IMZ-SPECT in the diagnosis of brain disorders in 169 patients with degenerative neurological diseases and 37 patients with mental disorders such as neurotic, stress-related and somatoform disorders. In dementia, the decrease in activity in late images, obtained three hours after administration of 123I-IMZ, correlated negatively with the dementia score. In Parkinson's disease and spinocerebellar degeneration. 123I-IMZ showed a more profound decrease in uptake in late images than seen in the cerebral blood flow (CBF) images, and this decrease was in proportion to the duration and severity of the illness. In mental disorders, the ratio of the late to early image counts showed a negative correlation with Hamilton's anxiety scale in all regions in the brain cortices. In panic disorders, the ratio of the cerebral count to the cerebellar count in the late images correlated negatively with the severity of the attack in the frontal, temporal and parietal cortices. These results suggest that 123I-IMZ-SPECT enables us to evaluate the neuronal damage in degenerative diseases and the decrease in the BZR binding potential in mental disorders.

Topics: Adult; Aged; Brain; Female; Flumazenil; GABA-A Receptor Agonists; Humans; Iodine Radioisotopes; Japan; Male; Mental Disorders; Middle Aged; Nerve Degeneration; Nervous System Diseases; Predictive Value of Tests; Tomography, Emission-Computed, Single-Photon

Clinical evaluation of 123I-iomazenil, a new imaging agent for central-type benzodiazepine receptors with SPECT, was performed in patients with ischemic cerebrovascular disease. We investigated 15 patients with angiographically-proven severe occlusive lesions (occlusion or > 70% stenosis) in the unilateral carotid system. 123I-iomazenil SPECT images were compared with cerebral blood flow (CBF) images and the cerebral perfusion reserve, which were measured using the "split dose 123I-IMP SPECT method" before and after the intravenous injection of 1 g of acetazolamide. For the detection of ischemic lesions, CBF images were superior to 123I-iomazenil images based on visual analysis. Regarding the count ratio of the affected MCA territory to the non-affected (L/N), 123I-IMP was lower than 123I-iomazenil in most of the cases. In five patients showing "crossed cerebellar diaschisis" by 123I-IMP, asymmetry of the cerebellar accumulation was observed in only one patient with 123I-iomazenil, which was less prominent than with 123I-IMP. There was no significant correlation between the L/N ratio with 123I-iomazenil and the cerebral perfusion reserve in the affected MCA territory. However, in some cases showing a decreased L/N ratio (< 90%) with 123I-iomazenil, a decreased CBF with normal perfusion reserve and cerebral hemi-atrophy were observed with 123I-IMP and MRI, which suggested the influence of neuronal loss due to chronic ischemia. These results indicate that 123I-iomazenil SPECT, which provides new information regarding neuronal loss due to ischemic damage to the brain, is useful for the evaluation of ischemic cerebrovascular disease.

Topics: Adult; Aged; Amphetamines; Brain; Cerebrovascular Disorders; Female; Flumazenil; Humans; Iodine Radioisotopes; Iofetamine; Male; Middle Aged; Nerve Degeneration; Neurons; Radionuclide Imaging; Regional Blood Flow

A 50-year-old woman presented with progressive visual disturbance, ataxia, and dementia. The cerebral cortex became atrophic, as the disease progressed, and electroencephalography showed periodic synchronous discharges. The patient's prion gene revealed a point mutation (232Met to Arg), and a diagnosis of Creutzfeldt-Jakob disease was made. Iomazenil single-photon emission computed tomography (SPECT) was performed to assess neuronal degeneration. Accumulation of the tracer in the late images was severely decreased diffusely spread throughout the cerebral cortex. Our experience with this case suggests that iomazenil SPECT is useful for detecting neuronal degeneration in Creutzfeldt-Jakob disease.

Topics: Brain; Brain Chemistry; Cerebellar Ataxia; Creutzfeldt-Jakob Syndrome; Female; Flumazenil; Humans; Middle Aged; Myoclonus; Nerve Degeneration; Nerve Tissue Proteins; Point Mutation; PrPC Proteins; Receptors, GABA-A; Tomography, Emission-Computed, Single-Photon