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Biomedical subjects

M Araki

Publications and source records attributed to M Araki.

At least 181 records · Page 10Linked to original sources
PubMed1988

Neuroleptic malignant syndrome: caffeine contracture of single muscle fibers and muscle pathology.

The neuroleptic malignant syndrome (NMS) is similar to anesthesia-induced malignant hyperthermia (MH) in three major clinical features: hyperthermia, muscular rigidity, and myoglobinuria. In eight cases of NMS, we studied caffeine contracture of single skinned muscle fibers. Sensitivity of the sarcoplasmic reticulum to caffeine was abnormally increased in six of the eight cases. Morphologic studies showed type 2B fiber atrophy in all six cases examined, and there were necrotic fibers in two cases. Since skeletal muscle is affected in NMS, these patients may be susceptible to MH.

Adolescent↗
PubMed1988

Electron microscopy of hepatitis B virus core antigen expressing yeast cells by freeze-substitution fixation.

We have used the freeze-substitution fixation technique for electron microscopy of yeast cells that express the hepatitis B virus core antigen (HBcAg) following transformation with the cloned gene. Abundant spherical particles were found within the transformed cells. These particles had a uniform size and shape, measured about 21 nm in diameter, had electron-lucent centers, and consisted of many subunits. They were localized in both the cytoplasm and the nucleus. None of these particles was found in the cells of the parent strain. Comparison of the HBcAg particles isolated from the yeast cells and the particles within the yeast cells demonstrated that the 21-nm particles were in fact ultrastructurally superimposable on HBcAg. Thus, the HBcAg particles within the yeast cells were similar to the HBcAg particles in human liver tissues infected with hepatitis B virus, not only in their size and appearance, but also in their intracellular localization. These results suggest that the yeast cell has the same machinery for synthesis and intracellular translocation of the HBcAg polypeptides as the human cell.

Animals↗
PubMed1987

Transplantation of cultured human spinal cord cells into the rat motor cortex: use of Phaseolus vulgaris leucoagglutinin as a cell marker.

Successful transplantations have been made of cultured explants of human fetal spinal cord into surgically created cavities in the motor cortical area of non-immunosuppressed young adult rats. The cultured cells were marked by brief incubation with Phaseolus vulgaris leucoagglutinin (PHA) just prior to transplantation. Following sacrifice of the rats 1.5 months later, PHA immunohistochemistry clearly outlined the demarcation zone of the explants. The transplanted neurons possessed long, somewhat tortuous fibers with occasional varicosities, as well as some thick processes. These findings extend our previous studies in which it was shown that cultured human fetal adrenal medulla and sympathetic ganglia cells could be successfully transplanted to non-immunosuppressed rat brain. They also suggest that PHA may be a valuable marker for transplanted cells at least for 1.5 months post-transplantation.

Culture Techniques↗
PubMed1987

The effect of DDB on dystrophic hamsters: an in vivo and in vitro study.

Dimethyl-4, 4'-dimethoxy-5, 6, 5'-6'-dimethylenedioxybiphenyl-2, 2'-dicarboxylate (DDB) is a synthetic analogue of Schizandrin C, an active compound isolated from a Chinese herb, Fructus schizandrae. We administered this compound to dystrophic hamsters in vivo for 31 days. This led to a 61% reduction of the calcium content, an 86% reduction of the area of calcium deposits, and a 52% reduction of the area of necrosis of cardiac muscle. However, skeletal muscle necrosis was not significantly improved. No clear change in plasma creatine kinase (CK) was observed. In an in vitro incubation study, the rate of CK release and tetanus tension of the extensor digitorum longus muscle of dystrophic hamsters were not substantially changed by the addition of DDB. This study suggests that DDB has some effect on cardiac necrosis, and that it might be useful for treatment of the cardiac involvement in patients with muscular dystrophy or other conditions with accompaning Ca accumulation.

Animals↗
PubMed1987

A case of "myopathy with tubular aggregates" with increased muscle fibre sensitivity to caffeine.

A 23-year-old man with "myopathy with tubular aggregates" had suffered from exercise-induced muscle cramps for 1 year. His general and neurological findings were normal. Laboratory investigations were within normal limits except for a slightly elevated serum creatine kinase level. Muscle biopsy showed some small angular fibres and scattered type 2B fibres with prominent tubular aggregates originating from the sarcoplasmic reticulum. Since the muscle fibres contracted at a lower concentration of caffeine, increased muscle fibre sensitivity to caffeine is probably related to muscle cramps in this disorder. Tubular aggregates are then secondarily formed in the muscle fibres.

Adult↗
PubMed1987

Characterization of photoreceptor cell differentiation in the rat retinal cell culture.

Photoreceptor cell differentiation in the rat retina was studied in vivo and in vitro, using an immunohistochemical method to demonstrate opsin-like immunoreactivity. Cells in a dissociated monolayer culture expressed some properties characteristic of rat rod cells developing in vivo, including a ciliary structure and opsin-like immunoreactivity. Immunoblot analysis revealed that cultured retinal cells synthesize a polypeptide with the same molecular weight as that synthesized by the intact retina. Although the outer segment (OS) was not present in the culture, immunoreactive cells possessed a ciliary structure. Opsin-like immunoreactivity was found on the plasma membrane, including the cilia. The neuritic extensions were also intensely stained. In mature rod cells of the intact rat retina, opsin was detected only on the OS but, during development, it was found both in the somatic region of the rod cells and on the differentiating OS. During maturation of rod cells opsin immunoreactivity seemed to shift to the OS from other locations. However, some "displaced" photoreceptor cells, found in the inner nuclear layer and extending fibers bipolarly, retained immunoreactivity throughout their structure. The absence of polarized distribution of opsin in these cells is considered to be due to an abnormal environment, which may also be the case with cultured retinal cells. The present culture conditions will offer a useful model system to understand the cellular mechanism of the hereditary retinal dystrophy of rodent animals in which photoreceptor cells selectively degenerate.

Animals↗
PubMed1987

An economic anterograde axonal tracing method using Phaseolus vulgaris agglutinin (PHA) P-form.

Phaseolus vulgaris leucoagglutinin (PHA-L) has been demonstrated to be an excellent neuroanatomical anterograde tracer. So far there are relatively few applications of this technique, mainly due to the cost of the lectin. Instead of PHA-L, we have successfully used PHA-P, which is a crude and inexpensive form of PHA-L. The sensitivity of the present method, examined in the rat striatonigral pathway, is as high as that of the conventional method. Furthermore, a large amount of PHA-P, injected into the cat eye, demonstrated the retinofugal projection in detail.

Animals↗
PubMed1987

Expression of hepatitis B virus middle and large surface antigen genes in Saccharomyces cerevisiae.

The hepatitis B virus genome carries the surface antigen (SAg) gene and an open reading frame that encodes two SAg-related polypeptides: SAg with a 55-amino-acid N-terminal extension polypeptide and SAg with a 174-amino-acid N-terminal extension polypeptide. These are termed middle S and large S, respectively. These polypeptides or their glycosylated derivatives have been detected in Dane particles, but their chemical and biological properties have remained largely unknown because of their limited availability. We attempted to produce these proteins in Saccharomyces cerevisiae by placing the coding regions under the control of the promoter of the yeast glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene. Yeast cells carrying middle S and large S coding sequences produced 33,000- and 42,000-dalton products, respectively, each of which reacted with anti-S antibody and bound to polymerized human serum albumin, in accordance with the known properties of pre-S proteins from particles in human sera (K. H. Heermann, U. Goldmann, W. Schwartz, T. Seyffarth, H. Baumgarten, and W. H. Gerlich, J. Virol. 52:396-402, 1984; A. Machida, S. Kishimoto, H. Ohnuma, K. Baba, Y. Ito, H. Miyamoto, G. Funatsu, K. Oda, S. Usuda, S. Togami, T. Nakamura, Y. Miyakawa, and M. Mayumi, Gastroenterology 86:910-918, 1984). The middle S polypeptide is glycosylated and can be assembled into particles whose size and density are similar to those of SAg. However, this polypeptide was highly susceptible to proteolytic degradation into 29,000- and 26,000-dalton polypeptides, of which only the former retained the binding activity to polymerized albumin. The large S polypeptides are nonglycosylated, relatively stable, and do not seem to assemble into particles by themselves.

Cloning, Molecular↗