Biomedical subjects

N Amano

Publications and source records attributed to N Amano.

At least 19 recordsLinked to original sources

PubMed1992

Dopamine receptor antagonists increase markedly the quantity of retrograde transport of HRP in the rat masseteric motoneuron.

Horseradish peroxidase (HRP) was injected, bilaterally, into the rat masseter muscle, subsequent to an intramuscular or intraperitoneal injection of one of five dopamine antagonists (chlorpromazine and haloperidol as the D1 and D2 receptor antagonist, SCH 23390 as the specific D1 receptor antagonist, sulpiride and domperidone as the specific D2 receptor antagonist). Control rats received an injection of a corresponding vehicle solution. After a survival period of 16 h, the brainstem was cut into 60 microns cryosections and processed with the TMB technique. The amount of retrogradely transported HRP was quantitatively measured in terms of the amount of HRP reaction product present in the motoneuron by the method which we have developed using an image processing system combined with a light microscope and a TV camera. Chlorpromazine, haloperidol, SCH 23390 and sulpiride significantly raised the quantity of retrograde transport of HRP. On the contrary, domperidone which can not penetrate the blood-brain barrier showed no significant change in the amount of the retrograde transport. In addition, an intravenous injection of chlorpromazine (8 mg/kg) was found to increase the amplitude of monosynaptic masseteric reflex EMG activity evoked by stimulations of the mesencephalic trigeminal nucleus. These results suggest that a possible regulatory system involving the dopamine receptor in the uptake and retrograde transport of HRP from axon terminals to cell bodies of the masseteric motoneuron exists in higher order neurons which make synaptic contact with the motoneuron.

Animals↗

PubMed1992

Argyrophilic glial intracytoplasmic inclusions in multiple system atrophy: immunocytochemical and ultrastructural study.

Argyrophilic intracytoplasmic inclusions in oligodendrocytes (AGCIs) were seen in all of 15 cases of multiple system atrophy (MSA), and none in other neurodegenerative diseases, including 9 cases of Menzel-type olivopontocerebellar atrophy and 4 cases of Joseph's disease. The inclusions were widespread, not only in the olivopontocerebellar and striatonigral systems but also among fibers connecting their affecting lesions of MSA. Immunohistochemically, they were closely associated with tau, tubulins and microtubule-associated protein 5. Ultrastructurally, they consisted of 30- to 50-nm filaments (not tubules) and electron-dense granules, in varying proportions, and their formation is discussed. The specific occurrence of AGCIs could be a key to approach the pathogenesis of MSA.

Atrophy↗

PubMed1992

Gerstmann-Sträussler syndrome--a variant type: amyloid plaques and Alzheimer's neurofibrillary tangles in cerebral cortex.

This report presents a variant of Gerstmann-Sträussler syndrome (GSS). A 53-year-old female had developed slowly progressive dementia and atactic gait since the age of 45. No myoclonic jerks and periodic synchronous discharges were observed throughout the illness. The neuropathological study revealed that many amyloid plaques and widespread Alzheimer's neurofibrillary tangles (NFTs) appeared in the cerebral cortex. Characteristically, the plaques reacted with anti-prion protein and none of them reacted with anti-beta protein, and they were made of many components, including amyloid cores, macrophages laden with lipid granules and/or degenerated neurites. Neuropil threads were seen mainly in amyloid plaques. Moreover, plaques appeared which were confluent and laminar in arrangement in the fifth and sixth cortical layers and had a close relationship to the neuronal loss. There was no spongiform change in the cerebral cortex or cerebellum. The cerebellum was almost intact except for a few amyloid plaques. Ultrastructurally, some of the plaques simulated kuru plaques and others had many degenerated neurites possessing paired helical filaments and other accumulated organelles. GSS has been proposed to include cases with progressive ataxia, dementia and massive multifocal plaques in the brain with or without cerebral spongiform changes. The case presented here is a very peculiar case of GSS. Recently, similar cases have been reported in some large families, diagnosed as familial Alzheimer's disease. These cases may be a telencephalic form with numerous NFTs of GSS.

Alzheimer Disease↗

PubMed1992

The effect of a histidine-excess diet on cholesterol synthesis and degradation in rats.

Feeding a diet high in excess histidine (5% L-histidine) resulted in hypercholesterolemia and enlargement of the liver in rats. To clarify the mechanism of the hypercholesterolemia, cholesterol synthesis and degradation were followed. We found that hepatic 3-hydroxy-3-methylglutaryl-coenzyme A reductase activity in histidine-excess diet rats was significantly higher than in rats fed a basal diet. Incorporation of [3H] water into cholesterol of liver slices from rats fed the histidine-excess diet was higher than incorporation into liver slices from rats fed the basal diet (expressed per liver per 100 g body weight). In vivo incorporation of [3H] water into hepatic cholesterol was also higher, but the incorporation into cholesterol of the small intestine was lower in histidine-fed rats than in rats fed the basal diet (expressed per liver per 100 g body weight). Hepatic cholesterol 7 alpha-hydroxylase activity was similar in both groups. The data suggest that the hypercholesterolemia caused by histidine-excess diet appears to be due to the stimulation of cholesterol synthesis in the liver.

Animals↗

PubMed1992

Structural analysis of nucleic acids by precise denaturing gradient gel electrophoresis: II. Applications to the analysis of subtle and drastic mobility changes of oligo- and polynucleotides.

Precise denaturing gradient gel electrophoresis was effectively applied to various kinds of oligo- and polynucleotides. The analyses on oligonucleotides revealed that every oligonucleotide has its own characteristic normalized mobility profile (NMP), which can be used to identify, characterize and classify the molecules. The precise system also enabled us to obtain unequivocally the mobility transitions corresponding to the melting of hairpin structures of oligonucleotides, single-stranded (ss) DNAs, and RNAs. Another application to co-migration and separate migration experiments demonstrated that there were significant binding interactions between two species of ss molecules of similar mobility, even when they have little complementarity with each other. When the precise temperature gradient gel electrophoresis was applied to double-stranded DNAs, it could be confirmed with high reliability that the mobility transitions observed correspond to cooperative meltings and strand dissociations. Through these experiments, mu m, a parameter defined as a mobility transition point, was shown to be effective to deal with those phenomena quantitatively.

Base Sequence↗

PubMed1992

Reclassification of two strains of Arthrobacter oxydans and proposal of Arthrobacter nicotinovorans sp. nov.

Arthrobacter oxydans DSM 419 and DSM 420 have chemical and microbiological properties that are consistent with assignment to the genus Arthrobacter. Both organisms have the lysine-alanine-threonine-alanine peptidoglycan type. DNA-DNA pairing studies indicated that A. oxydans DSM 419 should be reclassified as Arthrobacter ureafaciens and that A. oxydans DSM 420T forms the nucleus of a distinct genomic species. We propose that A. oxydans DSM 420 should be reclassified as Arthrobacter nicotinovorans sp. nov. The type strain is strain DSM 420.

Amino Acid Sequence↗

PubMed1992

Tactile sensibility of sapphire endosseous dental implants.

Experiments are described in which the tactile thresholds of sapphire (bioceram) endosseous implants were measured and compared with those of natural teeth. The effects of local anaesthesia were determined in an attempt to localize the mechanoreceptors involved. The thresholds of the implants were higher than those of natural teeth but lower than those of another type of implant (alumina tubingen) examined in another study. The results of local anaesthesia testing indicated that the sensory receptors involved were located in the connective tissues around the implant.

Adult↗

PubMed1992

Stimulation of corticosterone secretion by dietary histidine in rats.

1. Liver glycogen accumulated within 3 days after the initiation of a histidine-excess diet. Serum corticosterone increased and serum insulin decreased, but plasma glucagon remained unchanged. 2. When 2 mmol (310 mg) of histidine was administered to fasted rats, serum corticosterone increased after 5 hr and tended to be higher 9 hr after administration. 3. Liver glycogen tended to accumulate after 5 hr and had accumulated significantly after 9 hr.

Adrenal Glands↗

PubMed1992

[The thalamic changes in progressive supranuclear palsy].

This report is to investigate neuropathological changes of the thalamus observed in progressive supranuclear palsy. Six autopsy cases were examined. They were 5 males and a female, whose age was between 57 and 72 years old. They developed dementia in various degrees and three of the cases showed periodic stuporous state and akinetic mutism in the last stage. The paraffined thin-sections were stained with hematoxylin-eosin, luxol-fast-blue, Holzer, modified Bielschowsky, Gallyas and anti-tau stainings. The histological changes were evaluated in the aspects of neuronal loss, fibrillary gliosis and neurofibrillary tangles. In conclusion, there were three types in six cases. The first was seen in two cases and that there appeared many Alzheimer's neurofibrillary tangles (NFTs) in medial nuclei, lateral and ventral nuclei as well as zona incerta and reticular nucleus. The second was observed in two cases and that the loss of nerve cells was severe, especially in medial nuclei and the dorsal part of lateral and ventral nuclei and fibrillary gliosis was observed beyond the lesions of neuronal loss. The third was that the appearance of NFTs was moderate in number and neuronal loss was minimal. Moreover, neuronal loss and NFTs of zona incerta were common in these cases. Argentophilic fibrillary inclusions were observed in the neuropil and astrocytes in all cases. It is important to investigate the correlations between neuropathological changes and clinical manifestations, especially in the peculiar type of dementia observed in PSP. The thalamic changes of PSP may play an important role in causing stuporous state and akinetic mutism as well as subcortical dementia.

Aged↗

PubMed1992

[Elevation of serum fucosyltransferase activities in malignant diseases--a sensitive tumor marker?].

Fucosyltransferase (FT) is considered to be one of the most important glycosyltransferases responsible for the synthesis of cancer-associated carbohydrate chains such as CA19-9 and SLX. To determine whether FT is a sensitive tumor marker, we measured the enzyme activity of FT in sera from 136 cancer patients, 14 patients with benign diseases and 59 healthy controls, by using PA (pyridylamino)-labeled type II biantennary oligosaccharide derived from human serotransferrin as an acceptor substrate. Serum FT activity was significantly elevated in patients with cancer compared to healthy controls. Analysis of the enzyme products using HPLC and various fucosidases with different specificity revealed that alpha 1----3 FT was responsible for most of the elevation of the enzyme activity in sera from cancer patients. It should be stressed that the alpha 1----3FT derived from cancer patients transferred fucose to terminal lactosamine residues of type II biantennary oligosaccharides already attached to sialic acid. This indicates that the substrate specificity is clearly different from that reported in normal sera and tissues. In addition to alpha 1----3FT, some glycosidases including fucosidase were also elevated in sera from cancer patients.

Biomarkers, Tumor↗

PubMed1991

Degeneration of the corticopontine tract in olivopontocerebellar atrophy.

Nine cases of sporadic olivopontocerebellar atrophy [Déjérine-Thomas type, multisystemic atrophy (MSA)] were examined histologically and electron microscopically with special reference to the corticopontine tract. Five of nine cases showed degeneration of the myelinated nerve fibres in this tract. More severe degeneration of the fibres at the level of the pons than the crus cerebri indicates that degeneration of the fibres may start axodistally. Electron microscopy revealed selective involvement of large fibres in olivopontocerebellar atrophy, in contrast to unselective axonal atrophy in dentatorubropallidoluysian atrophy. The problem whether the degeneration of the tract is primary or secondary due to the loss of the pontine neurons remains open. We believe the former to be most likely. Degeneration of the corticopontine fibres should be added to the list of neuropathological findings in sporadic olivopontocerebellar atrophy.

Adult↗

PubMed1991

[Study on argyrophilic inclusions of multisystem atrophy (Oppenheimer)].

UNLABELLED: Non-hereditary olivo-ponto-cerebellar atrophy (OPCA) and striato-nigral degeneration (SND) have been looked upon as a single disease entity called multisystem atrophy (MSA) by Oppenheimer. This study revealed that both intracytoplasmic argyrophilic inclusions (AI) in pontine neurons and glial (argyrophilic) cytoplasmic inclusions (GCIs) widely distributed in the CNS are characteristics of MSA. MATERIALS: a) 12 cases with MSA, b) 16 cases with autosomal dominant (AD) form of spinocerebellar degeneration (SCD): AD form of OPCA 5 cases, Joseph disease 4 cases, AD-dentatorubropallidoluysian atrophy (Naitoh & Oyanagi's form) 6 cases, AD-spastic ataxia (Brown) 1 case, c) 4 cases with autosomal recessive (AR) form of SCD: AR form of OPCA 1 case, myoclonic epilepsy with ragged-red fibers (MERRF) 1 case, complicated form of spastic paraplegia 2 cases, d) 6 cases with non-hereditary SCD including intoxications: late cortical cerebellar atrophy 1 case, alcoholic cerebellar degeneration 2 cases, phenytoin-induced cerebellar degeneration 1 case, neuroleptic malignant syndrome 1 case, and e) 27 cases with other neuropsychiatric diseases: Alzheimer disease 20 cases, progressive supranuclear palsy 5 cases, schizophrenia 2 cases. METHOD: We examined 10 mu-thick paraffin sections stained with HE, Klüver-Barrera, Bodian, Holzer, Gallyas, and Bielschowski methods. RESULTS: AI in pontine neurons were found only in two cases of MSA. Interestingly no AI could be detected even in cases with AD form of OPCA showing mild degeneration in the pontocerebellar system. On the other hand, GCIs were found in all cases with MSA irrespective of the degree of degeneration in the olivo-ponto-cerebellar or striato-nigral system. However, there was no GCIs in cases with other form of SCD and other neuropsychiatric diseases. Gallyas stain was the best method for detecting GCIs. GCIs were widely distributed in the CNS except for superficial layers of the cerebral cortex, the cerebellar cortex, and the dorsal column of the spinal cord. There were also many GCIs in the putamen, pontine base, and cerebellar white matter, even though these sites were well preserved.

Alzheimer Disease↗

PubMed1991

[A new type of complicated form of hereditary spastic paraplegia showing mental deterioration, quadriplegia with muscular atrophy, sensory disturbance, extrapyramidal disorders, and epilepsy].

UNLABELLED: This study proposes a new type of complicated form of hereditary spastic paraplegia (HSP) and some problems on a clinico-pathological classification of HSP. The present study includes three male and two female patients from two families (A and B). In the family A, four siblings (two males and two females) were affected. Spastic paraplegia developed as an initial symptom. In the family B, a man was affected with spastic paraplegia which had started at the age of eleven. His two half-sisters are normal. All parents in two pedigrees are healthy. The parents in the family B are first cousins. CLINICAL FEATURES: Their physical development was normal, but all of them showed mild mental retardation. Gait disturbance due to spastic paraplegia and mental deterioration developed at the age of high teens. At the age of high 20's, they became unable to walk, because of progressive spastic paraplegia and other complicated neurological impairments including pyramidal disorders in the upper limbs, generalized neurogenic muscular atrophy, sensory disturbance and bradykinesia. Some cases showed rigidity and/or spasticity. At the age of high 30's, they became bed-ridden, because of quadriplegia with generalized muscular atrophy. Three cases in the family A suffered from convulsions which started at the high 30's. Mild athetoid movement in the face and neck was observed in three cases in the family A. All patients became apathetic and indifferent at least by the age of 40. Laboratory findings and data: CT scan yielded brain atrophy and dilatation of the lateral ventricles, atrophy of the corpus callosum and hyperostosis of the cranium.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

[Severe bradycardia and hypotension during spinal anesthesia: a report of five cases without morbidity].

We reported five cases of sudden onset of bradycardia and hypotension during spinal anesthesia in which measurable parameters of the patients were monitored continuously by inter-operating-room local area network system. In the first two cases, episodes of bradycardia and hypotension were caused by incomplete spinal blockade. In the third patient, severe bradycardia was preceded by gradual decrease of heart rate following high spinal blockade. In the last two cases of high spinal anesthesia, no remarkable change of the heart rate was observed before sudden onset of bradycardia and hypotension. All five patients were easily and adequately treated and they showed no signs of hypoxia. We would like to emphasize the importance of adequate and continuous monitoring during spinal anesthesia.

Adolescent↗

PubMed1991

[A method for measuring the amount of retrogradely transported HRP in the rat masseteric motoneuron using Mesulam's HRP histochemical protocol and an image processing system. An investigation of the effect of dopamine receptor antagonists on the retrograde transport of HRP].

We developed a method for a determination of the amount of retrogradely transported HRP in the rat masseteric motoneuron using a modification of Mesulam's HRP histochemical protocol and an image processing system combined with a light microscope and a television camera. To test the validity and reproducibility of the new method, a quantitative comparison of the amount of dark blue granules of HRP-product in the cell body of masseteric motor neurons was performed between the right and left trigeminal motor nuclei of 70 rats, which resulted in no significant difference. An additional study used the method was made of the effects of administration of five dopamine receptor antagonists with different biochemical and pharmacologic properties on retrograde transport of HRP in the rat masseteric motoneuron. As a result, chlorpromazine, haloperidol, SCH 23390, and sulpiride significantly enhanced retrograde transport of HRP as against domperidone which showed no significant change in the transport. A possible regulatory system for retrograde transport of HRP in the masseteric motoneuron was discussed in relation to the action of the dopamine receptor.

Animals↗

PubMed1991

[Clinical study on total intravenous anesthesia with droperidol, fentanyl and ketamine--4. Control of intraoperative hypertension with nicardipine].

Intraoperative hypertension over 160 mmHg systolic observed during total intravenous anesthesia with droperidol, fentanyl and ketamine was treated with intravenous nicardipine in 50 surgical patients. Nicardipine was given intravenously in a bolus of either 0.5 mg or 1.0 mg to treat the intraoperative hypertension. Systolic and diastolic blood pressures decreased soon after administration of nicardipine without simultaneous sinus tachycardia. Thus rate pressure product was also reduced significantly. Neither preoperative hypertension, nor systolic blood pressure just before the administration of nicardipine had any significant relationship with hypotensive effect of intravenous nicardipine. We did not experience any adverse reaction with the drug. We conclude that intravenous nicardipine in a dose of 0.5-1.0mg can be given repeatedly to overcome hypertension observed during this method of anesthesia.

Adolescent↗

PubMed1990

Morphological characteristics of senile plaques in familial Alzheimer's disease.

The distribution and morphology of senile plaques (SPs) in the cerebral cortices and subcortical nuclei of six cases of familial Alzheimer's disease (AD) were examined using the Methenamine-Bodian method and compared with those of sporadic AD cases. SPs were grouped into three types according to their morphology. SP types were generally constant at each anatomical site in all of the cases. The SPs of familial cases, however, had a greater tendency to fuse together than those of sporadic cases, especially in the cingulate cortex, presubiculum and striatum. This tendency was more evident in cases with severe amyloid angiopathy. Here it appeared that a SP type corresponding to "diffuse plaques", at least in part, might be formed by transformation from another type. In the globus pallidus, all the familial cases had many compact-like plaques which appeared to be derived from "drusige Entartung" of the capillaries. Furthermore, the regional proportion of two types of SPs occurring in this nucleus varied along its anteroposterior axis. These findings may be the histological hallmarks of atypical AD rather than familial AD.

Alzheimer Disease↗

PubMed1990

Senile dementia of Alzheimer type characterized by laminar neuronal loss exclusively in the hippocampus, parahippocampus and medial occipitotemporal cortex.

Seven cases of senile dementia of Alzheimer type (SDAT) with unusual clinico-pathological findings are reported. The patients showed neuronal loss in laminar pattern, with gliosis exclusively confined to the CA1 of the hippocampus, the area of the hippocampal gyrus (entorhinal cortex) and medial occipitotemporal cortex. This change was more pronounced in the oral region. The subcortical white matter showed more pronounced fibrillary gliosis than loss of myelin. Both Alzheimer's neurofibrillary tangles and senile plaques were less marked than those usually seen in SDAT. The mental disturbance started after the age of 65 in all patients. The main clinical feature was marked character change in addition to disturbance of cognitive function. Cranial computed tomography showed marked dilatation of the oral portion of the inferior horn of the lateral ventricle in the early stage. It was apparent that although the cases in this group could be incorporated within in the spectrum of SDAT, they could also be considered to represent a variant of SDAT. This group could contribute to an understanding of the clinico-pathological spectrum of SDAT as well as indicating ways of managing such patients.

Aged↗