Keita Kawabata

Quantitative evaluation of vascular permeability in the gerbil brain after transient ischemia using Evans blue fluorescence.

Mongolian gerbils were used to evaluate brain edema during restoration of flow following bilateral carotid occlusion for 1 h. We have modified the method for fluorometric measurement of Evans blue to monitor vascular protein leakage (vasogenic edema). The extraction of extravasated Evans blue was performed by homogenizing the whole brain in 50% trichloroacetic acid. The supernatant was diluted fourfold with ethanol and the Evans blue fluorescence was measured. The tissue blank was negligible. Evans blue content of the plasma was similarly determined and the ratio of tissue to plasma Evans blue content was calculated. Furthermore, Evans blue fluorescence was used for microscopic investigation. It is suggested that Evans blue fluorescence can be applied for quantification of protein leakage with much more sensitivity and accuracy than the colorimetric absorbance method, as well as for tissue localization of protein leakage.

Twelve-Month Follow-Up Study of Regional Cerebral Blood Flow in Parkinson's Disease

Measurement of regional cerebral blood flow (rCBF) in 30 patients with Parkinsons disease using single-photon emission computed tomography and 123I-IMP demonstrated that hypoperfusion was relatively severer in the parietal cortex than other cortices before and after a 1-year follow-up period. The decline in the scores of the Mini-Mental State Examination was significantly correlated with the decrease in rCBF in the parietal cortex during the follow-up period. Our findings suggest that the parietal cortex is involved in the cognitive impairment in patients with Parkinsons disease.

Cerebral blood flow in Parkinson's disease, dementia with Lewy bodies, and alzheimer's disease according to three-dimensional stereotactic surface projection imaging

Regional brain perfusion was analyzed using single-photon emission computed tomography with three-dimensional stereotactic surface projections (3D-SSP) in 69 patients with Parkinson’s disease (PD), 16 patients with dementia with Lewy bodies (DLB) and 15 patients with Alzheimer’s disease (AD), and compared with that in 24 age-equivalent normal subjects. Nondemented PD patients revealed less parietal and frontal flow than controls. With mental impairment, flow reduction extended to other areas including occipital regions. PD with dementia and DLB showed similar reduction patterns, although frontal flow showed a greater reduction in DLB. AD showed little occipital reduction, but a severe parieto-temporal reduction. Thus, 3D-SSP appears to be useful in the detection of cortical lesions and the differential diagnosis of patients with cognitive impairment.

Slowly progressive limb-kinetic apraxia with a decrease in unilateral cerebral blood flow.

We report two patients with slowly progressive motor disorders, whose principal manifestations were asymmetric limb‐kinetic apraxia and muscle rigidity. In both patients MRI revealed no responsible lesion, whereas single photon emission computed tomography (SPECT) showed a decrease in cerebral blood flow (CBF) in the unilateral hemisphere. One patient with mainly right‐sided apraxia had a decreased CBF in the left central region between the frontal and parietal cortices, and the other patient with left‐sided apraxia in the right parietal cortex. In agreement with asymmetric clinical symptoms, the regional CBF decrease in the unilateral cortical areas including the frontal and parietal cortices may suggest a degenerative disease, presumably diagnosed as having corticobasal degeneration.

Cerebral Blood Flow and Dementia in Parkinson's Disease

Regional cerebral blood flow (CBF) was examined in 27 patients with Parkinsons disease using single-photon emission computed tomography and N-isopropyl-p-[123I]iodoamphetamine as a tracer. Their CBF pattern was compared with that of seven patients with Alzheimers disease and nine age-matched neurologically normal controls. Tracer activity was determined in seven bilateral cerebellar, cortical, and subcortical regions and was expressed as the ratio of activity in each region to the mean tracer activity in the cerebellar region. Nineteen patients with nondemented Parkinsons disease showed significantly decreased tracer activity ratio in the frontal and temporal cortices, basal ganglia, and thalamus compared with that in controls. The eight demented Parkinsons disease patients showed significantly decreased tracer activity ratio in the temporal and parietal cortices compared with the patients without dementia, and demonstrated CBF pattern similar to that of patients with Alzheimers disease. These findings suggest that in patients with Parkinsons disease, the mechanism of CBF reduction of the frontal cortical region differs from that in the temporoparietal cortical region and support the concept that Parkinsons disease and Alzheimers disease may overlap in some patients. (J Geriatr Psychiatry Neurol 1991;4:194-203).

The role of the left somatosensory cortex in human hand movement

Hemispheric dominance for motor control in the human brain is still unclear. Here we propose asymmetric sensorimotor integration during human hand movements. We investigated the dexterity of hand movements and related sensory functions in four right-handed patients with cerebrovascular lesions in the postcentral gyrus. To clarify the distributions of cortical damage, semiquantitative analysis of regional cerebral blood flow (rCBF) was performed using single photon emission computed tomography (SPECT), and a three-dimensional surface display was generated from SPECT. Scores on motor and sensory tasks and rCBF values in the patients were compared with those in control subjects. All patients presented with asymmetric clumsiness of complex finger movements, in association with impairments of combined sensations such as stereognosis. These findings were indicative of a disorder of sensory information processing necessary to guide the movements. Two patients with left hemispheric damage showed bilateral clumsy hands, predominating on the right side, while the other two patients with right hemispheric damage showed only a left clumsy hand. In agreement with asymmetric clumsiness, measurement of rCBF along with a three-dimensional surface display revealed cortical hypoperfused areas, mainly in the perirolandic cortices, comprising the primary motor and somatosensory cortices. Perirolandic cortical hypoperfusion was bilateral in the two patients with bilateral clumsy hands, but only on the right side in the other two patients with left clumsy hands. These results suggest a dominant role of the left somatosensory cortex in sensorimotor integration for complex finger movements of humans.

Brain perfusion imaging in Parkinson's disease and Alzheimer's disease demonstrated by three-dimensional surface display with 123I-iodoamphetamine

We reconstructed three-dimensional (3D) surface images from data from single-photon emission computed tomography (SPECT) with N-isopropyl-p[123I]-iodoamphetamine (123I-IMP) in 29 patients with Parkinsons disease, 16 patients with Alzheimers disease and 11 normal control subjects. In patients with nondementing Parkinsons disease, perfusion defects were frequently found in the parietal cortical region at a threshold value of 65%. In demented Parkinsons disease patients, perfusion defects were frequently noted at threshold of 45-65%, and were more marked in the bilateral temporal and parietal cortices. In Alzheimers disease, perfusion defects were similar to those found in dementing Parkinsons disease. These results suggest that dementia in Parkinsons disease is related to the perfusion reduction of the temporoparietal cortex, and may support the view that Parkinsons disease and Alzheimers disease overlap in some patients. A 3D display of an 123I-IMP brain tomogram may be useful for detecting cortical lesions in patients with dementia or cognitive impairment.

Comparison of Brain Perfusion in Corticobasal Degeneration and Alzheimer’s Disease

To compare brain perfusion between corticobasal degeneration (CBD) and Alzheimer’s disease (AD), we measured regional cerebral blood flow (rCBF) semiquantitatively with single-photon emission computed tomography in 10 patients with CBD and 16 with AD. There was no significant difference in age or illness duration between the patients with CBD and AD. Mini-Mental State Examination scores were significantly lower in the AD patients than in the CBD patients. All CBD patients showed asymmetric akinetic-rigid syndrome and limb apraxia. Four CBD patients were demented, and 1 AD patient had parkinsonism. Compared with 12 age-matched control subjects, the average of the left and right rCBF values for the CBD patients was significantly reduced in the prefrontal, anterior cingulate (AC), medial premotor, sensorimotor (SM), posterior parietal (PP) and superior temporal (ST) cortices as well as in the basal ganglia (BG) and thalamus (Th), while the prefrontal, PP and ST cortices were significantly hypoperfused in the AD patients. In the CBD patients, rCBF was significantly less in the AC and SM cortices, and in the Th and BG, and significantly greater in the PP cortex than in the AD patients. Interhemispheric differences of rCBF in the inferior prefrontal and SM cortices were significantly greater in the CBD patients than the AD patients. It is concluded that rCBF comparison may aid in differentiating CBD from AD.

Focal cortical hypoperfusion in corticobasal degeneration demonstrated by three-dimensional surface display with123I-IMP: a possible cause of apraxia

To clarify cortical lesions responsible for apraxia in corticobasal degeneration (CBD), we reconstructed three-dimensional surface images from single-photon emission computed tomography (SPECT) data withN-isopropyl-p[I-123]-iodoamphetamine in two patients with CBD. Both had limb-kinetic apraxia (LKA) and one also had constructional apraxia (CA). Both showed asymmetrical cortical hypoperfusion in the perirolandic area. The patient with CA had unilateral hypoperfusion in the posterior parietal area. Thus, cortical hypoperfusion in the perirolandic area corresponded to LKA, and that in the posterior parietal area to CA.

Electrophysiological comparison between corticobasal degeneration and progressive supranuclear palsy

Multimodal evoked potentials were recorded in four patients with corticobasal degeneration (CBD), four patients with progressive supranuclear palsy (PSP) and 15 normal control subjects. CBD and PSP patients showed significant prolongation of the N200 and P300 latencies of auditory event-related potentials compared with controls. Patients with CBD showed significant prolongation of interpeak latencies between N13 and N20 of short-latency somatosensory evoked potentials compared with the controls and patients with PSP. The present results show that the two diseases have different electrophysiologic features.