Biomedical subjects
K Kanemaru
Publications and source records attributed to K Kanemaru.
Cerebrospinal fluid homovanillic acid levels are not reduced in early corticobasal degeneration.
To investigate the contribution of nigral degeneration to the development of parkinsonism in the early stages of corticobasal degeneration (CBD), we measured the cerebrospinal fluid (CSF) levels of homovanillic acid (HVA) in patients with early CBD (n = 5), and compared the levels with those in patients with early Parkinson's disease (n = 11) and in normal subjects (n = 13). The mean CSF HVA level in the early CBD group (33.1 +/- 6.0 ng/ml) did not differ significantly from that in the control group (37.1 +/- 12.7 ng/ml), whereas that in the early Parkinson's disease group (19.0 +/- 7.6 ng/ml) was reduced significantly (P < 0.001). This result suggests that neuronal cell loss in the substantia nigra and presynaptic nigrostriatal dopaminergic neuron dysfunction are mild in the early stages of CBD.
Cytotoxic actions of FTY720, a novel immunosuppressant, on thymocytes and brain neurons dissociated from the rat.
Effects of FTY720 (2-amino-2-(2-[4-octylphenyl]ethyl)-1,3-propanediol HCl), a novel immunosuppressant, were examined on neurons and thymocytes respectively dissociated from rat brains and thymus glands using a flow cytometer to see if FTY720 exerts cytotoxic actions not only on spleen cells as previously reported but also on the other cells. FTY720 at a concentration of 10 microM deteriorated almost all of the thymocytes, while it was not the case for brain neurons. FTY720 increased the intracellular concentration of Ca2+ ([Ca2+]i) of thymocytes in both the presence and absence of external Ca2+, although the [Ca2+]i increased by FTY720 in the presence of external Ca2+ was much greater than that in the absence of external Ca2+. Thus, FTY720 may increase the membrane permeability of Ca2+ and release Ca2+ from intracellular Ca2+ stores in thymocytes. Furthermore, the number of thymocytes stained with ethidium, a dye impermeant to intact membranes, time-dependently increased after drug application. Therefore, FTY720 at concentrations of 3 - 10 microM non-specifically increases the membrane permeability of thymocytes, resulting in necrotic cell death, although FTY720 at micromolar concentrations was reported to induce apoptosis of spleen cells.
[Familial parkinsonism: different clinical phenotype between a mother and her daughter].
We reported a familial case of parkinsonism in which clinical features are different between a mother and her daughter. The mother developed rigidity and bradykinesia at age 76. Her symptoms were slowly progressive, and were responsive to levodopa. Thus, she was diagnosed as having Parkinson's disease. In contrast, her daughter developed postural instability as well as rigidity and bradykinesia at age 53 in rapid progression. In addition, she also developed pyramidal signs and autonomic failures, including orthostatic hypotension and urinary incontinence. The disease phenotype of the daughter resembled that of striatonigral degeneration (SND). However, PET studies showed normal binding of 11C-N-methyl-spiperone (NMSP) in the striatum, suggesting that the daughter was also affected with Parkinson's disease.
[Gait disturbance without motor and sensory involvement in cervical myelopathy--clinical course and radiological findings].
Among 100 patients with cervical myelopathy, we found 7 patients with gait disturbance in which motor or sensory involvements were absent (group A). In these patients, the gait was unsteady, but not ataxic nor spastic. Some of them showed mild hyperreflexia, but no one had Romberg's sign. We compared the effect of neck traction and radiological findings in group A with these in 25 patients who had gait disorders as well as other symptoms associated with cervical myelopathy (group B). Mean age in group A (mean 83.9 +/- 7.9 ys) was older than that in group B (mean 76.6 +/- 5.7 ys). Gait disorders improved in 6 cases of group A (86%), and 5 cases in group B (20%) by conservative therapy of Glisson's traction. On plain X-ray examination, the physiologic lordosis of cervical spine was preserved, the cervical canal diameters from C2 to C7 were more wide, and the number of intervertebral excessive mobility had tendency to be less in group A than in group B. Cervical MRI indicated that the number of intervertebral spinal compression was less in group A than in group B. In the cervical myelopathy, there was a type showing only gait disturbance which was characterized by the good response to Glisson's neck traction, and by the preserved physiological lordosis, relatively wide spinal canal, and slight intervertebral compression.
Comparable amyloid beta-protein (A beta) 42(43) and A beta 40 deposition in the aged monkey brain.
Two distinct species of amyloid beta-protein (A beta), A beta 42(43) and A beta 40, are deposited in the brains of patients with Alzheimer's disease and normal aged individuals. A beta 42(43), the long tailed A beta, is the initially and predominantly deposited species in senile plaques. Deposition of A beta is also observed in the aged monkey brains. We investigated the A beta species in the aged monkey brains immunocytochemically using monoclonal antibodies that discriminate between the C-termini of A beta 42(43) and A beta 40. We report here that A beta 40 as well as A beta 42(43) deposit in various types of senile plaques, including diffuse plaques of the aged monkey brain and that the ratio of A beta 40 to A beta 42(43) is higher compared with that in human brain.
Ginkgo biloba extract protects brain neurons against oxidative stress induced by hydrogen peroxide.
Effect of Ginkgo biloba extract was examined on dissociated rat cerebellar neurons suffering from oxidative stress induced by hydrogen peroxide using a flow cytometer and ethidium bromide. Hydrogen peroxide at a concentration of 3 mM increased the number of neurons stained with ethidium (presumably dead neurons) in a time-dependent manner. Pretreatment of neurons with G. biloba extract (10 micrograms/ml) greatly delayed a time-dependent increase in number of dead neurons during exposure to hydrogen peroxide. It was true, but less effective, in the case of treatment with G. biloba extract immediately or 60 min after start of oxidative stress. Results implicate G. biloba extract as a potential agent in protecting the neurons suffering from oxidative stress induced by hydrogen peroxide.
Flow cytometric analysis of the H2O2-induced increase in intracellular Ca2+ concentration of rat thymocytes.
The effect of hydrogen peroxide (H2O2) on the intracellular Ca2+ concentration ([Ca2+]i) of rat thymocytes was examined by a flow cytometer and two fluorescent dyes, fluo-3-AM and ethidium bromide, a dye impermeant to intact membranes, to characterize the H2O2-induced increase in [Ca2+]i. H2O2 at concentrations greater than 30 microM dose-dependently increased the [Ca2+]i of thymocytes which were not stained with ethidium. Removal of external Ca2+ greatly reduced the degree of H2O2-induced increase in [Ca2+]i. However, H2O2 still increased the [Ca2+]i under the external Ca(2+)-free condition. Diethylmaleate, which is known to produce a chemical depletion of cellular nonprotein thiol, significantly increased the [Ca2+]i. Dithiothreitol, which is used to protect cellular nonprotein thiol, slightly decreased the [Ca2+]i, but greatly reduced the H2O2-induced increase in [Ca2+]i. Therefore, it is considered that H2O2 may increase the [Ca2+]i through a mechanism related to the effects of H2O2 on the cellular nonprotein thiol.
[Effect of apolipoprotein E phenotype on cerebrospinal fluid levels of tau in patients with dementia of Alzheimer type].
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Expression of cathepsin G-like and alpha 1-antichymotrypsin-like proteins in reactive astrocytes.
The central nervous system (CNS) of many different species responds to diverse neurologic injuries with an activation of astrocytes. Yet, the exact function of this reactive astrocytosis is unknown. In this report, mouse astrocytes were activated in vivo by focal penetrating brain injury. Reactive astrocytes were stained with antibodies raised against the serine protease cathepsin G (cat.G), the serine protease inhibitor alpha 1-antichymotrypsin (ACT), or the astrocytic marker glial fibrillary acidic protein (GFAP). Reactive astrocytes expressing both cat.G-like and ACT-like antigens were found around cerebral wound margins between 18 h and 13 days after neural lesions. The injury-induced immunostaining was unaltered by 900 rads of total body irradiation, suggesting that the astroglial reaction was relatively independent of bone marrow-derived cells. The in vivo immunostaining was complemented with biochemical assays on cultured primary astrocytes. A synthetic peptide was used as a substrate in combination with specific inhibitors to identify a proteolytic activity within astroglial lysates and culture supernatants that closely resembles cat.G. This activity increased substantially upon stimulation of astrocytes with dibutyryl cyclic AMP and was neutralized by antibodies raised against cat.G. In a separate report, it was shown that astrocytes also contain an ACT-like inhibitory activity. The production of ACT- and cat.G-like antigens and activities by activated astrocytes should allow these cells to participate in a number of important biologic processes. Many of these processes may benefit the CNS by assisting in early wound repair. However, astroglial proteases and their inhibitors could also contribute to the pathogenesis of certain neurologic diseases.
Purification and cloning of brain proteases capable of degrading the beta-amyloid precursor protein.
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Fetal-type phosphorylation of the tau in paired helical filaments.
To determine the phosphorylation sites of the tau in paired helical filaments (PHF), two types of PHF antisera with different specificities were used: One was a conventional anti-PHF, and the other was an antiserum to formic acid-denatured PHF (anti-HFoPHF). Phosphorylated tau-specific antibodies, anti-ptau 1 and anti-ptau 2, were prepared from anti-PHF and anti-HFoPHF, respectively. We found that both anti-ptau 1 and anti-ptau 2 labeled fetal or juvenile tau but not adult tau. The anti-ptau 1- and anti-ptau 2-recognition sites were immunochemically localized to the fragment Asp313 to Ile328 in the most COOH-terminal portion of tau. Furthermore, Ser315 was determined as the anti-ptau 2 recognition site. The sequence surrounding Ser315 was not found in the canonical sequences phosphorylated with known kinases.
[Computerized tomography immediately after surgery in the neurosurgical operating theater].
A TCT-300 scanner (manufactured by the Toshiba Co., Tokyo) has been installed in the operating room of Shinshu University Hospital since 1986. This neurosurgical operating CT scanner system was developed for obtaining intra- and postoperative CT images in the operating room. We have carried out immediate postoperative CT scanning in 206 cases: 170 were major and 36 were minor operations. A mobile CT scanner gantry has been used in 125 cases since June, 1988. We obtained CT images immediately after surgery on the digitalized operating table, the motion of which can be controlled as with the conventional CT scanner table. Immediate postoperative CT scans showed the extent of removed tumors or hematomas, position of the tip of ventricular or cisternal tubes, injury to the surrounding normal brain caused during the removal of lesions, and postoperative complications such as hemorrhage, brain swelling and surgical patties which had been inadvertently left in the wound. This CT scanner system in the operating room proved to be useful in the postoperative care of neurosurgical patients.
[Abnormal proteins in the brain in Alzheimer's disease].
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Digitally controlled neurosurgical operating table--technical note.
The authors describe a new, digitally controlled operating table for neurosurgery. The apparatus includes a digitally controlled motor for manipulating the table and a rotary encoder with a central processing unit, which calculates and displays the table's position. The table can be operated with any type of digitalized computer system and its position is monitored by the encoder unit in real time.
The presence of a novel protein in calf serum that recognizes beta amyloid in the formalin-fixed section.
Here we report on a monoclonal antibody, H6-33, that labels various beta-amyloid plaques, including diffuse plaques in the formalin-fixed, paraffin-embedded section from the brain affected with Alzheimer's disease (AD), without formic acid pretreatment. H6-33 also labels some neurofibrillary tangles and all kuru plaques in Gerstmann-Sträussler-Scheinker disease. In sharp contrast, H6-33 did not stain beta amyloid in the leptomeningeal vessel. For specific staining, H6-33 required the presence of fetal calf serum and it was necessary for beta amyloid to be formalin fixed. These results suggest that a novel protein in the calf serum, CSX, binds formalin-fixed beta amyloid, followed by H6-33 binding. The detection of beta amyloid by CSX was nullified by formic acid pretreatment of the tissue section. In accordance with this, CSX reacted only with a polymer form of synthetic beta peptide after fixation, but not with native beta-protein or beta-peptide monomer. These observations strongly suggest that 1) meningovascular beta amyloid should have a beta-pleated sheet structure somewhat dissimilar to that of beta-amyloid cores; and 2) most, if not all, of beta-protein immunoreactivities of diffuse plaques in AD sections are presumably derived from small amounts of amyloid fibrils scattered in the normal-looking neurohil.
The Marfan syndrome with an XYY chromosome pattern.
A 36-year-old man who was diagnosed to have the Marfan syndrome with an XYY chromosome pattern is reported. He was tall with long limbs and arachnodactylia, and had severe aortic regurgitation (AR). The chromosome pattern studied in specimens of blood and bone marrow revealed an XYY chromosome pattern. The relationship between the Marfan syndrome and an XYY chromosome pattern is discussed.
[Brainstem infarction caused by occlusion of the persistent primitive hypoglossal artery. A case report].
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