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Biomedical subjects

S Ishimoto

Publications and source records attributed to S Ishimoto.

At least 55 records · Page 3Linked to original sources
PubMed1987

Biochemical studies in mitochondrial encephalomyopathy.

The alpha-keto acid dehydrogenase complex and its component enzymes, lactate dehydrogenase, pyruvate carboxylase, cytochrome c oxidase, succinate-cytochrome c reductase, NADH-cytochrome c reductase, and the concentration of cytochromes and enzymes of beta-oxidation in muscle from a patient with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes were studied and no specific defect was found. These results raise the possibility that the mitochondrial changes in the patient may be secondary.

Acidosis, Lactic↗
PubMed1986

The rigid spine syndrome and Emery-Dreifuss muscular dystrophy.

We present five patients, three of whom suffered from a rigid spine syndrome and two from Emery-Dreifuss muscular dystrophy. One patient with rigid spine syndrome showed a nonprogressive course, normal cardiac rhythm and mild myopathic changes in muscle histology, while in the other two patients there was a rapidly progressive course, sinus tachycardia without cardiac conduction defects and marked fiber necrosis in muscle histology. The two patients suffering from Emery-Dreifuss muscular dystrophy showed a very mildly progressing course, myopathic changes in muscle histology, cardiac conduction defects and deviations in electrocardiograms. These findings show that rigid spine syndrome can be distinguished from Emery-Dreifuss muscular dystrophy.

Adolescent↗
PubMed1984

Isolation and identification of 1 alpha,25-dihydroxy-24-oxovitamin D3, 1 alpha,25-dihydroxyvitamin D3 26,23-lactone, and 1 alpha,24(S),25-trihydroxyvitamin D3: in vivo metabolites of 1 alpha,25-dihydroxyvitamin D3.

Three new in vivo metabolites of 1 alpha,25-dihydroxyvitamin D3 were isolated from the serum of dogs given large doses (two doses of 1.5 mg/dog) of 1 alpha,25-dihydroxyvitamin D3. The metabolites were isolated and purified by methanol-chloroform extraction and a series of chromatographic procedures. By cochromatography on a high-performance liquid chromatograph, ultraviolet absorption spectrophotometry, mass spectrometry, Fourier-transform infrared spectrophotometry, and specific chemical reactions, the metabolites were identified as 1 alpha,25-dihydroxy-24- oxovitamin D3, 1 alpha,25-dihydroxyvitamin D3 26,23-lactone, and 1 alpha,24(S),25-trihydroxyvitamin D3. According to these procedures, the total amounts of the isolated metabolites were as follows: 1 alpha,25-dihydroxyvitamin D3, 23.6 micrograms; 1 alpha,25-dihydroxy-24- oxovitamin D3, 1.8 micrograms; 1 alpha,25-dihydroxyvitamin D3 26,23-lactone, 9.2 micrograms; 1 alpha,24(R),25-trihydroxyvitamin D3, 15.4 micrograms; 1 alpha,24(S),25-trihydroxyvitamin D3, 1.0 microgram. With recovery corrections, the serum levels of each metabolite were approximately 49 ng/mL for 1 alpha,25-dihydroxyvitamin D3, 3.7 ng/mL for 1 alpha,25-dihydroxy-24- oxovitamin D3, 19 ng/mL for 1 alpha,25-dihydroxyvitamin D3 26,23-lactone, 32 ng/mL for 1 alpha,24(R),25-trihydroxyvitamin D3, and 2.1 ng/mL for 1 alpha,24(S),25-trihydroxyvitamin D3.

Animals↗
PubMed1984

Biological activity assessment of 1 alpha,25-dihydroxyvitamin D3-26,23-lactone in the rat.

1 alpha,25-Dihydroxyvitamin D3-26,23-lactone [1 alpha,25(OH)2D3-26,23-lactone] was compared to 1 alpha,25-dihydroxyvitamin D3 [1 alpha,25(OH)2D3] in terms of their stimulation, in vivo, of intestinal calcium transport and mobilization of calcium from bone in the rat (the two classic vitamin D-mediated responses), and their relative binding to the chick intestinal receptor for 1 alpha,25(OH)2D3, 1 alpha,25-(OH)2D3-26,23-lactone was found to be only one-thirtieth as active as 1 alpha,25-(OH)2D3 in the stimulation of intestinal calcium transport and was found to mediate a significant reduction in the steady-state serum calcium levels. Associated with the reduction in serum calcium was a significant increase in urinary calcium excretion for 24 h after the administration of the steroid. Prior administration of 1 alpha,25(OH)2D3-26,23-lactone partially blocked the actions of a subsequently administered dose of 1 alpha,25(OH)2D3 in increasing serum calcium levels, but did not affect the action of 1 alpha,25(OH)2D3 in stimulating intestinal calcium transport. The binding affinity of 1 alpha,25(OH)2D3-26,23-lactone to the chick intestinal cytosol receptor protein was observed to be 670 times lower than that of 1,25-(OH)2D3 which indicates that perturbation of the 25-hydroxylated side chain by formation of the 26,23-lactone causes a significant reduction in ligand affinity for the receptor.

Animals↗
PubMed1984

[An autopsy case of chorea-acanthocytosis. Special reference to the histopathological and biochemical findings of basal ganglia].

Chorea-acanthocytosis has been separated as a clinical entity different from Huntington's chorea, mainly based on the clinical findings, but the histopathological and biochemical features of chorea-acanthocytosis, especially of basal ganglia, have not been well established, because only two such autopsy cases have been reported. The case presented here was a 39-year-old man at autopsy, with 10 years duration of typical symptoms and signs of chorea-acanthocytosis. At autopsy, the abnormal histopathological findings in the central nervous system were mainly confined to the striatum, where the caudate nucleus and putamen showed severe and moderate atrophy, respectively. Morphometric evaluation of the numbers of small and large neurons in the striatum with the adjustment for the shrinkage produced in the disease processes was performed. The numbers of small neurons in the caudate nucleus and putamen were 1% and 20% of each control, respectively. On the other hand, the large neurons in the caudate nucleus showed a reduction of diameters without a decrease in number and those in the putamen showed a mild decrease in number. In the biochemical studies, marked decrease of substance P (SP) level without definite decrease of choline acetyltransferase and glutamic acid decarboxylase (GAD) activities in both caudate nucleus and putamen was found. Substantia nigra, where no evident histopathological abnormalities were found, showed definite decrease of GAD activity and SP level. In the peripheral nervous system, the lateral branch of deep peroneal nerve showed mild degree of axonal degeneration. Neurogenic muscular atrophy with severe and mild degrees was found in extensor digitorum brevis and quadriceps femoris muscles, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Acanthocytes↗