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Biomedical subjects

H Nagara

Publications and source records attributed to H Nagara.

At least 37 records · Page 2Linked to original sources
PubMed1987

Emery-Dreifuss muscular dystrophy. An autopsy case.

We reported the autopsy findings in a 50-year-old man with typical clinical features of Emery-Dreifuss muscular dystrophy. Special attention was directed to the spinal cord and ventral spinal roots to determine whether cause of the muscle wasting was denervation or myopathy. Neuropathological studies disclosed no abnormality of the spinal cord, and the ventral spinal roots were intact. The skeletal muscles showed dystrophic changes of varying degrees, and marked cardiomyopathy was evident. We consider that muscle wasting in this man was due to muscular dystrophy.

Anterior Horn Cells↗
PubMed1987

Accumulation of galactosylsphingosine (psychosine) in the twitcher mouse: determination by HPLC.

We developed a sensitive and simple procedure for determination of galactosylsphingosine (psychosine), using HPLC. The method involved extraction of lipids, separation by cation-exchange and C18 reverse-phase columns, and derivatization with o-phthalaldehyde. The fluorescent galactosylsphingosine was detected by HPLC. The amount of galactosylsphingosine was accurately assayed by simultaneous determination of glucosylsphingosine, as the internal standard. The detection limit was 0.5 ng/assay tube, and the quantitative range of the method was up to 750 ng. This procedure was applied to tissue from the twitcher mouse, an animal model of human globoid cell leukodystrophy, as well as tissue from normal and carrier mice. In the latter mice, a small amount of galactosylsphingosine was detected in the spinal cord (21.6-37.2 ng/100 mg wet weight) but not in the cerebrum and sciatic nerve. Marked accumulation of galactosylsphingosine was noted in the nervous tissues of the twitcher strain, even on postnatal day 4. The concentration of galactosylsphingosine was greater in the peripheral than in central nervous tissues. The spinal cord and brainstem contained more galactosylsphingosine than did the cerebrum and cerebellum. The concentration increased with age from 764 ng/100 mg in the sciatic nerve at 4 days to 5,910 ng/100 mg at 37 days. These data correlate well with the pathological changes; tissues containing higher concentrations of galactosylsphingosine show earlier and more severe pathological changes than those containing lower concentrations, thereby indicating the close link of galactosylsphingosine to the pathogenesis of the twitcher mouse.

Animals↗
PubMed1987

Hyperosmotic blood-brain barrier disruption in brains of rats with an intracerebrally transplanted RG-C6 tumor.

To test the results of blood-brain barrier (BBB) disruption in the treatment of brain tumor, RG-C6 glioma was transplanted into the brains of rats. Intracarotid infusions of normal saline and hyperosmotic mannitol were then made, followed by intravenous injection of Evans blue dye plus albumin (EB, MW 68,000), horseradish peroxidase (HRP, MW 40,000), and 5-fluorouracil (5-FU, MW 130). Uptake of the drug and the consistency of drug levels in the normal brain and tumor varied widely among these three agents. Both EB and HRP penetrated the brain tumors but did not stain the normal brain tissues. After BBB opening, penetration of EB and HRP into the normal brain was drastically increased; however, the uptake of EB and HRP in the tumor was not increased. The concentration of 5-FU in the tumor was higher than that in the serum and, although it increased 1.5-fold after BBB opening, the increase was not statistically significant. Conversely, there was a progressive increase in concentrations of 5-FU in the tumor-free brain regions (p less than 0.05). These observations suggest that an intracarotid infusion of hyperosmotic mannitol may increase neurotoxicity because it allows greater delivery of anticancer drugs into the normal brain tissue than into the tumor tissues.

Animals↗
PubMed1986

Thiamine-deficient encephalopathy in rats: effects of deficiencies of thiamine and magnesium.

Thiamine- and vitamin B-deficient encephalopathy was produced in adult Wistar rats and the effect of magnesium deprivation and/or the administration of guanidine, a magnesium antagonist, was studied. These encephalopathic rats had symmetrical lesions, edema, exudation of fibrin, spongy changes, petechial hemorrhages, neuronal degeneration and gliosis in the pontine tegmentum, mainly the lateral and medial vestibular nuclear areas. Mild pathological changes were seen in the purely thiamine- or vitamin B-deficient rats, whereas severe pathological changes occurred in thiamine- or vitamin B-deficient rats combined with magnesium deprivation and/or guanidine administration. However, magnesium-deficient diets or guanidine administration did not produce pathologic changes in rats. These findings suggest that thiamine deficiency is an essential factor in the development of these pathological changes in the brainstem, and that magnesium and guanidine, an antagonist of magnesium, play important roles in the development of these disorders.

Animals↗
PubMed1986

The twitcher mouse: degeneration of oligodendrocytes in vitro.

Oligodendrocytes were isolated from the brain of the twitcher (twi/twi), an authentic murine model of globoid cell leukodystrophy (GLD), carrier (+/twi) and their littermate controls (+/+) and were maintained in vitro for 24 days. By 4 days in vitro (4 DIV) oligodendrocytes developed thorny processes and their morphology were closely similar to each other regardless of their genetic status. After 17 DIV, however, oligodendrocytes in twi/twi progressively degenerated and only 12% of oligodendrocytes counted at 10 DIV survived at 24 DIV in twi/twi, while in +/twi and +/+, mean survival rates were 85 and 83% respectively. Characteristic inclusions of GLD were detected in the perikarya of degenerating twi/twi oligodendrocytes indicating that metabolic defect was expressed even in isolated oligodendrocytes. These results further support the hypothesis that the primary pathogenetic event in murine GLD, twitcher, is degeneration of oligodendrocytes due to progressive accumulation of the toxic metabolite, galactosylsphingosine (psychosine).

Animals↗
PubMed1986

[An autopsy case of malignant schwannoma in the brachial plexus extending into the spinal canal].

A 40-year-old woman had pain and numbness in the left upper extremity, on Dec. 1982. These symptoms progressed gradually. She was admitted to our department on Jan. 26, 1984 because of neck pains and progressive paraplegia. Neurological examination revealed monoplegia of the left arm with absent DTRs, spastic paraplegia, sensory disturbances below Th 11 level and severe sphincter disturbance. A metrizamide myelogram showed intradural extramedullary mass at C 4-7. Laminectomy was immediately performed from C 3 to C 7. A soft and brown tumor was attached at the ventral aspect of the cord at C 3 and C 7 and it was firmly attached at the root sleeve of the C 5 level. The histological diagnosis of the tumor was malignant schwannoma. One month later, she was discharged on foot. However, she was re-admitted to our department because of intractable pains in left neck and arm in Aug. '84. The second operation was done on Sept. 15. A soft and brown mass was found intra- and extradurally and it invaded into paravertebral muscules. On Sep. 30 '84 she died from respiratory failure. Postmortem examination revealed that intra-extradural tumor was found at C 4-Th 3, and the left brachial plexus was swollen. In the brachial plexus, the nerve fiber was replaced with tumor in the perineurium. The tumor invaded to the vertebral body and the paravertebral muscles. There were numerous metastasis of the tumor in both lungs. The tumor was formed by variable and scanty cytoplasm with many mitotic figures.(ABSTRACT TRUNCATED AT 250 WORDS)

Brachial Plexus↗
PubMed1985

A new method to classify amyloid fibril proteins.

The permanganate method, the immunoperoxidase method, and a newly developed autoclave method were used to distinguish different types of amyloid fibril proteins in formalin-fixed, paraffin-embedded tissue sections. All tissues from permanganate-sensitive cases (AA type) lost the affinity of Congo red and green birefringence under polarized light after incubation with special autoclave treatment. AL type systemic amyloidosis and amyloid plaques of CJD and GSS were permanganate-resistant, but decreased markedly the affinity of Congo red after prolonged autoclaving. On the other hand, prealbumin type systemic amyloidosis and senile plaques of SDAT were resistant to both permanganate oxidation and prolonged autoclaving. Thus, amyloid plaques of CJD and GSS are identical to AL type in systemic amyloidosis, and senile plaques are similar to the prealbumin type. However, anti-prealbumin antiserum did not stain senile plaque amyloid. The anti-human P component stained positively systemic amyloids and cerebral amyloid plaques of SSE, but failed to stain senile plaques of SDAT. Therefore, the amyloid fibril protein of senile plaques is apparently different from other types of amyloid depositions. Amyloid plaques of SSE are different from senile plaques not only with regard to fibril proteins, but also to globular protein in the amyloid.

Adolescent↗
PubMed1985

Morphogenesis of amyloid plaques in mice with Creutzfeldt-Jakob disease.

Amyloid plaques were experimentally produced in the brains of mice inoculated with human Creutzfeldt-Jakob disease (CJD) brain homogenate. Light-microscopically, these plaques were mostly round and oval and were surrounded by macrophages and astrocytes. Ultramicroscopically, amyloid plaques were present in the cytoplasm of macrophages or were surrounded by these cells. The macrophages had numerous Golgi apparatuses, endoplasmic reticula (ER), ribosomes, polysomes, and lysosomes with inoculated materials or degenerating products. The bundles of amyloid fibrils were intermingled with the cytoplasm of macrophages, and sometimes limiting membranes were absent. Some bundles of amyloid fibrils projected from the Golgi apparatuses or rough ER and were partly exposed to the extracellular spaces, but there were no amyloid fibrils in the lysosomes. These findings confirmed that amyloid fibrils in the brains of CJD-infected mice were produced by macrophages.

Amyloid↗
PubMed1984

Amyloid plaques in the brains of mice with Creutzfeldt-Jakob disease.

By intracerebral inoculation with the brain homogenates from 9 patients with Creutzfeldt-Jakob disease, amyloid plaques were induced in mouse brains after incubation periods of 403 to 835 days. The plaques existed mainly in the cerebral white matter beneath the lateral ventricle walls and were more numerous in the hemisphere where injection was made. Morphological findings of the plaques were almost identical to those seen in patients with kuru and Creutzfeldt-Jakob disease, and in animals with scrapie. They were also similar to the cores of senile plaques seen in patients with Alzheimer's disease.

Adult↗
PubMed1984

Intranuclear inclusions in muscle, nervous tissue, and adrenal gland.

A 30-year-old man had had chronic progressive wasting and weakness of muscles for 17 years. A muscle biopsy 5 years prior to death revealed myopathic changes were rimmed vacuoles and intranuclear inclusions which corresponded to "inclusion body myositis". At autopsy, intranuclear inclusions were observed in neurons, oligodendroglia, and in parenchymal cells of the adrenal medulla. Ultrastructurally, the inclusions in muscles, nervous tissue, and adrenal medulla were identical and consisted of abnormal tubulolinear structures measuring 10-20 nm in diameter. Similar inclusions have been reported in muscles with "inclusion body myositis" and in the nervous system with "neuronal intranuclear hyaline inclusion disease", respectively. Absence of clinical symptoms related to the CNS and adrenal gland, and well-preserved parenchymal cells in these organs of our patient suggest a benign nature of the disease except in the muscular system. Attempts to isolate a virus from the brain were fruitless . This patient may serve to connect both diseases in muscles and the nervous system, and to disclose the etiology of these inclusions.

Adrenal Glands↗
PubMed1984

Experimental transmission of human subacute spongiform encephalopathy to small rodents. IV. Positive transmission from a typical case of Gerstmann-Sträussler-Scheinker's disease.

Spongiform encephalopathy was transmitted to mice from a patient belonging to the "Sch" family with Gerstmann-Sträussler-Scheinker's disease (GSS). Incubation periods in the first passage were much shorter than those in mice infected with Creutzfeldt-Jakob disease. Clinical and pathologic findings of mice infected with both diseases were almost identical. This is the first successful transmission from a typical GSS case without severe spongiform change which suggests the possible transmissible nature of this disorder.

Animals↗