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Biomedical subjects

R Fukatsu

Publications and source records attributed to R Fukatsu.

At least 55 records · Page 3Linked to original sources
PubMed1993

Magnetic field responses to visual stimulation in human parietal association cortex.

The neural activities of the parietal association cortex were studied in humans through the use of a 37-channel SQUID magnetometer system. The magnetic field responses were recorded in the parietal association cortex following visual stimulation with LED light. Main responses peaking at about 120, 170 and 220 msec after LED onset were observed. The estimated current dipole sources of the magnetic field responses at latencies of 160-190 and 210-270 msec were revealed to be located in the intraparietal sulcus. A change in the magnetic field responses with the eye position was found in the amplitude.

Adult↗
PubMed1991

Unilateral spatial neglect in visual and tactile modalities.

The purpose of this study was to investigate whether a unilateral spatial neglect phenomenon occurs in the tactile modality in the absence of visual information. Ten patients with clinically confirmed visual spatial neglect and 10 normal controls bisected lines visually, or by touch when blindfolded. In visual presentation, the rightward deviation of the subjective midline was significantly more prominent in patients with visual spatial neglect than in normal controls. However, in the tactile tasks, there was no significant difference between the patient group and controls. From these results it was concluded that visual input may play an important role in the occurrence of the unilateral spatial neglect phenomenon.

Adult↗
PubMed1990

Auditory sound agnosia without aphasia following a right temporal lobe lesion.

A 55-year-old right-handed man showed inability to recognize the meaning of non-verbal sounds without impairment of language comprehension after a cerebrovascular accident. His auditory acuity was intact and no other sign of agnosia, apraxia or aphasia was detectable. His errors on a test of sound recognition were acoustic rather than semantic. Brain CT scan showed a small lesion in the posterior part of the right temporal lobe. This case suggests that auditory sound agnosia without language disorder can ensure a lesion confined to the right hemisphere, and that the deficit is discriminative rather than associative in nature.

Agnosia↗
PubMed1990

Effects of hand and spatial conditions on visual line bisection.

This study examined the effects of hand and spatial conditions on a visual line bisection task with normal right-handers and proposed a normal range of deviation for this task in middle and advanced age. Twenty-four normal dextrals in their fifties and sixties performed a visual line bisection task using either the left or right hand under three spatial conditions: at the midline and in the left and right hemispaces. Our results revealed that performance was significantly affected by the hand used but not spatial conditions: Left hand performance was significantly further leftward than right hand performance. There was no significant interaction between the hand and spatial conditions. The mean deviation of the right hand was 2.2% of the half line length to the right of the true center. The possibility of left unilateral spatial neglect should be considered if a patient bisects a line with a deviation greater than 10% of the half line length to the right.

Aged↗
PubMed1989

[Hyperkinetic mutism within the scope of consciousness disorder in a case of systemic lupus erythematosus].

A thirty-year-old housewife, who had been diagnosed as SLE, had been hyperkinetic and mute for 13 months after reiteration of manic-depressive episodes. In this condition she walked around without aim, ate and drank only with nursing help, and could not understand the circumstances around her; she was incontinent of urine and feces. Serological examination did not show any abnormal results during psychic exacerbation. She recovered dramatically by electroconvulsive therapy, and was completely amnestic about the past 15 months. Because her mental state was considered to be limited consciousness, it might be possible that her hyperkinetic and mute state is situated between twilight state and akinetic mutism.

Adult↗
PubMed1988

Ultrastructural analysis of neurofibrillary tangles of Alzheimer's disease using computerized digital processing.

The ultrastructure of neurofibrillary tangles of Alzheimer's disease was analyzed by computerized digital processing of electron micrographs. Processing of the electron micrographs consists of four steps: digitizing the electron micrograph, Fourier transformation, noise filtering and inverse Fourier transformation and Laplacian operation. In the present study, we have confirmed that neurofibrillary tangles are composed of a pair of helical filaments (PHF), which appear characteristically as an unbranched rigid structure. The periodicity of PHF is 78 nm on the diffractogram. The dimensions of PHF obtained by our analysis, although basically similar to those described earlier by other investigators using conventional techniques, more precisely defines its structural conformation. We have also demonstrated that the spatial relationship of two filaments appears symmetrical after two-way tilting of the specimen about the axis of rotation. Our observations emphasize the importance of digital image processing as an effective tool for structural analytical research in biology and medicine.

Actin Cytoskeleton↗
PubMed1987

Binding and cytotoxic effects of Clostridium botulinum type A, C1 and E toxins in primary neuron cultures from foetal mouse brains.

Binding of purified Clostridium botulinum type A, C1 and E toxins to cultured cells was studied by an immunocytochemical method. Type A and C1 toxins bound strongly to neuron cultures prepared from brains of foetal mice, but binding of type E toxin was weak. None of the toxin types bound to the feeder layer, composed of non-neuronal cells. The heavy-chain component of the type C1 toxin bound to neurons, but the light chain component did not. Type C1 toxin also bound only to cell lines of neuronal origin. When type C1 toxin [final concentration 4 x 10(2) LD50 (10 ng) per well] was added to primary neuron cultures in 96-well plates, degeneration of neuronal processes and rounding of neuronal somas were observed, but type A and E toxins did not produce such changes. The binding and cytotoxic activities of type C1 toxin were blocked by heat treatment (80 degrees C for 30 min) or by preincubation of the toxin with polyclonal anti-C1 IgG and some of the monoclonal antibodies which neutralized the toxin activity in mice. In the neuronal processes treated with C1 toxin, many degenerated mitochondria, membranous dense bodies and vesicles were observed by electron microscopy; these ultrastructural changes were similar to those of Wallerian degeneration in vivo.

Animals↗
PubMed1987

Three cases of chronic bromisoval intoxication: clinical symptoms and application of energy dispersive X-ray analysis (EDX) to detect bromine in serum, urine and cerebrospinal fluid.

Bromisoval has been used as a hypnotic for the past several decades, and its abuse was known to cause various neurological as well as psychiatric symptoms. Three patients showed a variety of symptoms which could not be explained neuroanatomically: nystagmus, gait disturbance and hyperreflexia of the limbs in all the cases, dysarthria, double vision, hypotonia, ataxic gait and disturbance of consciousness occasionally and auditory agnosia in one case. For the purpose of determining the diagnosis, an energy dispersive X-ray microanalysis (EDX) was used to detect bromine. Five microliters of specimens were placed on the carbon-coated mesh, and using a TN-2000 analyzer, characteristic X-ray peaks of bromine were detected in the serum, urine and cerebrospinal fluid. The sensitivity to detect bromine in the serum was 30 micrograms/ml.

Adult↗
PubMed1987

Increased activity of oligo-2',5'-adenylate synthetase in Down's syndrome and epilepsy.

The level of oligo-2',5'-adenylate synthetase activity is a good marker for the response of cells to interferon. This enzyme can polymerize ATP to form oligonucleotides in the presence of double-stranded RNA, i.e. polyinosinate-cytidylate in vitro. The activity of this enzyme in peripheral blood mononuclear leucocytes was significantly increased in Down's syndrome (P less than 0.01) and epilepsy (P less than 0.01) compared with that in healthy controls, but the increase of activity was not significant in multi-infarct dementia (MID) (P greater than 0.05). Although the patients with Down's syndrome showed higher levels of this enzyme activity than the controls, interferon activity was never detected in the circulation. In addition, the serum of patients with Down's syndrome lacked the capacity to induce this enzyme in NC-37 and FL cells, and furthermore it was shown that the inhibitor of interferon activity was not found in the serum of patients. This discrepancy in Down's syndrome may be the result of the hypersensitivity of cells to interferon. On the contrary, interferon activity (32 IU/ml) was detectable in the circulation of one patient with epilepsy, and the serum of this patient had the capacity to induce this enzyme in NC-37 and FL cells.

2',5'-Oligoadenylate Synthetase↗
PubMed1984

Imaging of calcium and aluminum in neurofibrillary tangle-bearing neurons in parkinsonism-dementia of Guam.

We report the distribution and imaging of calcium and aluminum in neurofibrillary tangle (NFT)-bearing neurons within Sommer's sector of the hippocampus in Guamanian patients with parkinsonism-dementia, using a method of computer-controlled electron beam x-ray micro-analysis and wavelength dispersive spectrometry. Calcium and aluminum were distributed in cell bodies and axonal processes of NFT-bearing neurons. The elemental images show that both calcium and aluminum deposits occur within the same NFT-bearing hippocampal neuron in this dementing disease, suggesting that these elements are involved in NFT formation. No prominent concentrations of calcium and aluminum were imaged in non-NFT-containing regions within the pyramidal cell layer of the parkinsonism-dementia cases or in the control cases. These findings support the hypothesis that secondary hyperparathyroidism resulting from low environmental calcium and magnesium in the high-incidence focus of amyotrophic lateral sclerosis and parkinsonism-dementia on Guam had led to abnormal deposition of calcium and aluminum in the central nervous system.

Aged↗
PubMed1983

Ultrastructural studies on synaptic formations in dissociated fetal mouse brain cultures.

Sequential electron microscopic studies of cultures of neurons derived from dissociated fetal mouse brain on the eleventh day of gestation revealed the formation of well-developed synapses during the second and third weeks of growth in vitro. Synaptic junctions were associated with synaptic vesicles nd dense synaptic membranes. Dense-core vesicles were also observed frequently in presynaptic terminals.

Animals↗
PubMed1978

Pontine infarction with diffuse myelin destruction.

A 57-year-old man with clinical symptoms of dementia and spastic paraplegia revealed pathologically scattered cerebral arteriosclerotic changes and diffuse myelin destruction in the basis pontis. The latter was characterized by comcomitances with an eminent fibrous gliosis and a neuronal as well as an axonal loss. Pontine infarction and the following fibrous gliosis possibly caused a wide area of myelin destruction resembling cpm.

Cerebral Infarction↗