Biomedical subjects

I Akiguchi

Publications and source records attributed to I Akiguchi.

At least 163 records · Page 9Linked to original sources

PubMed1994

[Changes in glial cells in Binswanger-type infarction].

Changes in glial cells were investigated immunohistochemically in the autopsy brains of patients with Binswanger-type infarction and the brains of rats with chronic cerebral hypoperfusion. Activated microglia, which are positive for MHC class II antigen, and GFAP immunoreactive astroglia were 3.1 times and 1.6 times, respectively, more numerous, in Binswanger-type infarction than in normal white matter. Chronic cerebral hypoperfusion after bilateral permanent occlusion of the carotid arteries elicited marked activation of microglia and an increase in astroglia in the medical corpus callosum after 1 day of occlusion, and these findings persisted up to 30 days after the occlusion. A decreased number of transferrin-immunoreactive oligodendroglia and rarefaction of the white matter were noted after 14 days of occlusion. These findings indicate that chronic mild ischemia may lead to rarefaction of the white matter, and that the activation of glial cells, which precedes rarefaction of the white matter, may be involved in the pathogenesis of Binswanger-type infarction.

Aged↗

PubMed1994

[Intravenous immunoglobulin therapy in multifocal motor neuropathy].

We treated ten consecutive patients with multifocal motor neuropathy (MMN) with high-dose intravenous immunoglobulin. Ages ranged 18 to 58 years, with disease duration of 9 months to 8 years. We treated them with 0.2 g/kg of human immunoglobulin for 6 consecutive days. All but one showed a clinical improvement starting within a week after the first infusion. The functional improvement ranged from marked to mild degree. In six patients, the clinical effect abolished within 2 months. Improvement was persistent for more than 6 months in the other three. In only two patients conduction block improved after the treatment. The discrepancy may result from an increased threshold of remyelinated or chronically demyelinated fibers for excitation. Side effects were not documented. This pilot study indicates that immunoglobulin may be a safe and effective therapy for MMN.

Adolescent↗

PubMed1994

[Protective effect of nicardipine hydrochloride on the evolution of delayed neuronal death--an immunohistochemical study].

Alteration of evolution of delayed neuronal death in the gerbil after intraperitoneal injection of nicardipine was investigated by using immunohistochemistry for microtubule associated protein (MAP) which enables early detection of ischemic injuries. Male Mongolian gerbils were subjected to intraperitoneal injection of nicardipine at concentrations of 0.01-10 mg/kg and subsequent occlusion of bilateral carotid arteries for 5 min. Extent of the lesions estimated by immunohistochemistry for MAP was reduced at the dosages of 0.2 mg/kg nicardipine as compared with control, while lesser or larger amounts have failed to protect the brain tissue from ischemic insults. Furthermore, pre- and postoperative treatment of 0.2 mg/kg of nicardipine two times daily succeeded to partially attenuate the development of delayed neuronal death in gerbils which underwent ischemia for 5 min and subsequent reperfusion for 4 days. These results indicate that optimal concentration of nicardipine ameliorates delayed neuronal death, presumably because of the increase of cerebral blood flow and intervention of intracellular influx of calcium ions.

Animals↗

PubMed1993

Ulex europaeus I and glycine max bind to the human olfactory bulb.

The distribution of binding sites for the fucose-selective lectin Ulex europaeus I and the terminal N-acetylgalactosamine-selective lectin glycine max in the human olfactory bulb were studied. These lectins bound to primary olfactory axons in the olfactory nerve layer and the glomerular layer. They also bound to fibers located in the deeper layers such as the external plexiform layer and the granular layer. Furthermore they projected to the olfactory stalk but not in the cerebrum. The deeper projections of the lectin binding fibers may affect the function of the olfactory bulb in humans.

Aged↗

PubMed1993

A subpopulation of mouse striatal cholinergic neurons show monoamine oxidase activity.

We examined the histochemical localization of monoamine oxidase (MAO) in the mouse striatum. MAO activity was observed in glial cells and vessels in accordance with previous reports in the rat brain. In addition to these previously documented structures, we found MAO-containing neurons in the mouse striatum. Enzyme inhibition experiments showed that MAO in the positive neurons was predominantly of type B. Double-labeling studies showed that in this region these neurons were cholinergic. The functional role of MAO activity in the mouse striatal cholinergic neurons is presently unclear.

Acetylcholinesterase↗

PubMed1993

Astroglial expression of ATL-derived factor, a human thioredoxin homologue, in the gerbil brain after transient global ischemia.

Distribution of adult T cell leukemia derived factor (ADF/TRX), a human thioredoxin homologue, was studied by immunohistochemistry in gerbil brain during reperfusion after transient cerebral ischemia. In control brains, immunoreactivity was observed widely in the central nervous system, including the ependyma, tanycytes, endothelial cells as well as subcommisural organs, and weakly in the neuronal cell bodies. During reperfusion, ADF/TRX was expressed in glial cells in the CA1 and dentate hilus of the hippocampus, and in a few cases in the lateral portion of the caudateputamen. ADF/TRX positive glias first appeared after reperfusion for 24 h, and the intensity of staining peaked at 72 h and diminished after 7 days of reperfusion. They were concentrated around microvessels and identified to be astroglia by double labeling immunohistochemistry with glial fibrillary acidic protein as marker. Immunoblotting analysis demonstrated an increase of ADF/TRX in the postischemic hippocampus. Astroglial expression of ADF/TRX in postischemic injuries suggests a role in neuroprotection by hydrogen peroxide reducing and protein-refolding activities or in modulation of local immune responses.

Animals↗

PubMed1993

Cycloheximide downsynthesizes inhibitory molecules for neurite outgrowth in neural transplantation.

Rat fetal substantia nigra treated with cycloheximide, a protein synthesis inhibitor, were implanted to adult rat striatum. After 4 weeks, tyrosine hydroxylase (TH)-like immunoreactive (-LI) fibers of host striatum penetrated grafts, and TH-LI neurites in the grafts elongated and mingled with the host striatal neurites. Astrocytes proliferated in the grafts without glial scar between the graft-host border. A few chondroitin sulfate- or tenascin-LI glial cells were found in the grafts, while in transplants without cycloheximide, glial scar expressed strong immunoreactivity for these molecules. Downsynthesis of these inhibitory molecules may alter the glial character and permit neurites traversing the border.

Animals↗

PubMed1993

Distribution of NADPH-diaphorase in the cerebral blood vessels of rats: a histochemical study.

NADPH-diaphorase (neuronal nitric oxide synthase) activity in the cerebral blood vessels was investigated by light and electron microscopic histochemistry to elucidate the sites of nitric oxide production. Networks of adventitial nerves containing NADPH-diaphorase were distributed in all parts of the circle of Willis. However, NADPH-diaphorase activity in adventitial nerves was much sparser in the region of the posterior cerebral artery, and absent in the pial arteries smaller than 100 microns in diameter. Endothelial cells were intensely stained in arteries and arterioles. These results support the hypothesis that vascular tone is regulated by nitric oxide, which is derived from endothelial cells and adventitial nerves.

Amino Acid Oxidoreductases↗

PubMed1993

The histochemical demonstration of MPTP oxidation in the postmortem human striatum.

Monoamine oxidase (MAO) histochemistry has been performed in postmortem human striatal tissues using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) as substrate. The reaction products of MPTP oxidation in the human putamen and caudate nucleus were observed in glial cells. Although glial staining was found diffusely in the human striatum, prominently intense staining was observed in glial cells surrounding vessels. Double staining for MAO and glial fibrillary acidic protein showed that glial cells containing MAO activity were astrocytes. The inhibition experiments using clorgyline and 1-deprenyl as MAO inhibitors indicate that MAO associated with the present MPTP oxidation was of the B type. The present observations suggest that astrocytes, especially around vessels, may be involved in MPTP oxidation in the human striatum after systemic administration of MPTP.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗

PubMed1993

Age-related deterioration in conditional avoidance task in the SAM-P/10 mouse, an animal model of spontaneous brain atrophy.

A novel inbred strain of mouse 'SAM-P/10' (Senescence Accelerated Mouse) is a model of age-related brain atrophy characterized by age-related loss and shrinkage of neurons in the cerebral neocortex. Age-related changes in learning and memory skills of SAM-P/10 mice were investigated using a newly developed conditional avoidance task in a T-maze. Comparisons were made with findings in the SAM-R/1 strain which shows a little loss and no shrinkage of neocortical neurons. Four-month-old SAM-R/1 and SAM-P/10 performed well during a 10-day training schedule of the conditional avoidance task. SAM-R/1 mice over 17 months of age were slower learners than younger SAM-R/1 mice but reached nearly the same high percentage avoidance as seen in the 4-month-old mice during the last 4 days of the schedule. Performance of the SAM-P/10 mice gradually worsened with aging and 10- to 12-month-old SAM-P/10 mice could not reach the percentage avoidance seen with the 4-month-old mice, even after the 10-day training. When the mean percentage of successful avoidance or escape behavior on every training day was plotted, the curves were much the same for both SAM-R/1 and SAM-P/10 mice, of any age. These results show that aged SAM-P/10 mice retained the left-right turning discrimination in the T-maze and lost the ability to predict the forthcoming aversive shock by associating conditioned stimulus and unconditioned stimulus.

Aging↗

PubMed1993

Loss of large neurons and occurrence of neurofibrillary tangles in the tuberomammillary nucleus of patients with Alzheimer's disease.

We studied the number of large-sized neurons and neurofibrillary tangles (NFT) in the tuberomammillary nucleus (TM) of the hypothalamus from cases with Alzheimer's disease (AD) and age-matched controls. Numerous NFT were found in TM of AD. However, NFT was never observed in this nucleus of age-matched controls. The number of large-sized neurons was significantly reduced in AD compared with that in controls. Since the majority of large neurons in TM appear to correspond to histamine neurons, the loss of large neurons observed in TM may, at least partly, cause the histaminergic dysfunction in AD brain.

Aged↗

PubMed1993

Induction of c-Fos-like protein in the lateral habenular nucleus by persistent noxious peripheral stimulation.

Persistent noxious peripheral stimulation by formalin injection into the unilateral hindpad of anaesthetized rats induced c-Fos-like protein immunoreactivity (c-Fos-LI) in neurons within the lateral habenular nucleus (LHb) bilaterally. Formalin injection after the transection of spinal cords also induced c-Fos-LI in many neurons within the LHb, though the number of labeled cells changed depending on the post-transection period. These results suggest that the LHb modulates nociceptive information, but that it receives nociceptive information via extraspinal pathways as well as intraspinal ascending noxious pathways.

Animals↗

PubMed1993

Pathological findings at the site of conduction block in multifocal motor neuropathy.

We report on 2 patients with multifocal motor neuropathy with focal conduction block involving motor but not sensory fibers at the site of nerve swelling. A nerve biopsy specimen from adjacent to the enlargement in 1 patient showed a perivascular area containing scattered demyelinated axons surrounded by small onion bulbs. The observed pathological findings are consistent with the conduction block considered characteristic of this neuropathy, although the underlying immunological mechanisms for selectivity and persistence remain undetermined.

Action Potentials↗

PubMed1993

Ubiquitin-immunoreactive inclusions in anterior horn cells and hypoglossal neurons in a case with Joseph's disease.

We describe a patient with progressive spastic ataxia and ophthalmoparesis. His clinical and neuropathological findings were consistent with Joseph's disease. The most characteristic neuropathological features in the present case were ubiquitin-immunoreactive filamentous or dense inclusions in spinal anterior horn cells and hypoglossal neurons, which have been considered to be a specific finding in amyotrophic lateral sclerosis (ALS). The occurrence of ubiquitin-immunoreactive inclusions suggests that such inclusions are not totally specific to ALS and could occur in occasional degenerating motor neurons without apparent ALS neuropathology.

Adult↗

PubMed1993

Neurofibrillary tangles in the neurons of spinal dorsal root ganglia of patients with progressive supranuclear palsy.

Neurofibrillary tangles (NFTs) occur in neurons of human central nervous system (CNS) both in aged subjects and patients with several degenerative diseases, with a certain topographical predilection. In surveying the NFT distribution in nervous tissue of patients with progressive supranuclear palsy (PSP), we found silver-positive fibrillary tangles in the neurons of dorsal root ganglia (DRG) in two of five patients. By immunohistochemistry, these tangles were stained with antibodies to human tau protein, paired helical filaments (PHFs) and ubiquitin. Electron microscopy revealed that they were mainly composed of PHFs that were morphologically indistinguishable from PHFs in the NFTs of CNS typically seen in Alzheimer's disease brains. Our data demonstrate for the first time that the neurons of DRG produce NFTs in PSP and suggest that the pathological process(es) leading to tangle formation can occur in the neurons of the peripheral nervous system in this disease condition.

Aged↗

PubMed1993

Proton magnetic resonance spectroscopy with dementia.

To provide new insights into metabolic changes in the brain of patients with dementia, we performed in vivo localized proton magnetic resonance spectroscopy in nine patients with primary degenerative dementia and in three patients with normal-pressure hydrocephalus. We compared the results with those in 26 healthy volunteers. Measurements of regional cerebral blood flow were performed in seven patients by means of single photon emission computed tomography with amphetamine I 123 as a tracer. The magnetic resonance spectra constantly showed three major peaks corresponding to N-acetylaspartate (NAA), creatine and phosphocreatine (Cr), and choline-containing compounds. There were no age-related changes in the mean area ratio of NAA to Cr in neurologically normal volunteers. The NAA/Cr ratio was significantly reduced in patients with primary degenerative dementia. The reduction of the NAA/Cr ratio was observed even in dementia patients with no significant brain atrophy or reduction in regional cerebral blood flow. No significant reduction of the NAA/Cr ratio was seen in patients with normal-pressure hydrocephalus. The NAA/Cr ratio might reflect the number and/or activity of neuronal cells in the brain. Proton magnetic resonance spectroscopy may well provide a useful tool for early detection of, and further pathophysiological study of, primary degenerative dementia.

Adult↗

PubMed1993

Cheiro-oral-pedal syndrome in thalamic infarction.

Sensory disturbance around the corner of the mouth, in the palm of the hand and in the foot on the same side (cheiro-oral-pedal syndrome) has been reported only in 2 patients with brainstem lesion. We report 2 cases of cheiro-oral-pedal syndrome; the causative lesion was revealed by magnetic resonance imaging to be in the ventral postero-lateral and ventral posteromedial nuclei of the thalamus.

Aged↗

PubMed1993

Polymyositis associated with asymptomatic primary biliary cirrhosis.

We studied a 67-year-old female who suffered from polymyositis associated with primary biliary cirrhosis (PBC). Liver dysfunction was revealed by a screening test. Antimitochondrial antibodies (AMA) and antinuclear antibodies were positive. Liver biopsy was compatible with PBC (Scheuer stage I). Four years later she showed severe weakness and atrophy on her four extremities. Laboratory examination showed a creatinine kinase level of 312 IU/l, IgM 416 mg/dl, and AMA titer 1:320. Muscle biopsy findings were compatible with polymyositis. Electron microscopic examination disclosed diffuse increase of mitochondria in subsarcolemma and intermyofibrils, which has not been reported until now in polymyositis associated with PBC.

Aged↗