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Biomedical subjects

M Ohta

Publications and source records attributed to M Ohta.

At least 1,333 records · Page 74Linked to original sources
PubMed1978

Achilles tendon thickness and ischemic heart disease in familial hypercholesterolemia.

Achilles tendon thickness (ATT) of 112 patients with familial hypercholesterolemia (FH) with and without ischemic heart disease (IHD) was measured radiographically and was compared with that of normal subjects. The mean and SD of serum cholesterol in the heterozygotes (107 cases), the homozygotes (5 cases) and the normal subjects (36 cases) were 347 +/- 63, 589 +/- 69 and 187 +/- 30 mg/dl, respectively. The mean and SEM of ATT in the heterozygotes, the homozygotes and the normal subjects were 12.5 +/- 0.4 mm, 18.6 +/- 6.6 mm, and 6.3 +/- 0.2 mm, respectively. Cutaneous xanthomas were observed in 34 out of 112 patients (30.4%). Increased ATT was observed in 95 (84.8%). IHD was diagnosed in 39 (34.8%). The ATT of FH with IHD was significantly thicker than that of FH without IHD (P less than 0.05) and that of normal subjects (p less than 0.001). Thus, the increased ATT evaluated by x-ray was the earliest clinical sign of FH and the measurement of ATT seems to be a useful adjunctive procedure for detecting familial hypercholesterolemic patients and predicting IHD in them.

Achilles Tendon↗
PubMed1978

Metabolism of trichothecene mycotoxins. II. Substrate specificity of microsomal deacetylation of trichothecenes.

The substrate specificity of microsomal nonspecific carboxyesterase [EC 3.1.1.1] from rabbit and rat livers was studied in vitro by using seven (A)-type and six (B)-type 12,13-epoxytrichothecene mycotoxins. The C-4 acetyl residues of diacetoxyscirpenol, T-2 toxin, monoacetylnivalenol (fusarenon-X), and diacetylnivalenol were selectively hydrolyzed by the microsomal esterase to yield the corresponding C-4-deacetylated metabolites: monoacetoxyscirpenol, HT-2 toxin, nivalenol, and 15-acetylnivalenol, respectively. The C-3 acetyl group of monoacetyldeoxynivalenol and the C-8 acetyl group of tetraacetoxyscirpen were also deacetylated. Triacetoxyscirpen gave rise to two unidentified metabolites, which may include a C-4-deacetylated product. 8-Hydroxydiacetoxyscirpenol (neosolaniol), HT-2 toxin, acetyl-T-2 toxin and tetraacetylnivalenol were unaffected by this type of hydrolysis. It follow from these results that the C-4 acetyl residue is hydrolyzed by the microsomal carboxyesterase and substituents at C-3 and C-8 contribute to the selective enzymatic hydrolysis of the C-4 acetyl residue of trichothecenes. Kinetic analysis showed that rabbit microsomal esterase possessed a high affinity for (A)-type trichothecenes such as T-2 toxin and diacetoxyscirpenol, and that of rat microsomes possessed a high affinity for (B)-type trichothecenes such as monoacetylnivalenol (fusarenon-X). The significance of this specific deacetylation reaction is discussed in relation to the biological activity of the trichothecene derivatives as revealed by their inhibitory effect on protein synthesis in rabbit reticulocytes.

Animals↗
PubMed1978

Disruption of blood-retinal barrier at the retinal pigment epithelium after systemic urea injection.

Electron microscopic studies were done on the structural alterations of retinal pigment epithelial cells occurring under osmotic stress utilizing rhesus monkeys and lanthanum nitrate as a tracer. Fluorescein fundus angiography revealed leaking points of fluorescein from the choroid to the retina, and various degenerative alterations of the retinal pigment epithelial cells were observed in these leaking areas. Some cells included many vacuoles in their cytoplasm, but diffusion of lanthanum from the choroid to the outer segment of visual cell was obstructed by the tight junctions between the retinal pigment epithelial cells. Other cells were severely damaged with ruptured membranes. Abundant tracer material diffused through the cytoplasm into the subretinal space. Other cells were broken down in an isolated manner and here marked extravasation of lanthanum into the subretinal space was observed.

Animals↗
PubMed1978

[Dilatometry of gypsum bonded investment (author's transl)].

Although many investigations on the thermal expansion of dental investments have already been done, the conditions upon which thermal expansion was measured were not always definitely shown and the phenomena on thermal behavior of dental investments were not reasonably interpreted. In this investigation the effects of W/P ratio of samples, heating rate and furnace atmosphere were studied by "Push Rod" Dilatometer in order to attempt to standardise dilatometry of dental investments. All experiments were designed with two-way layout techniques. The main results were as follows, 1) W/P ratio, heating rate and furnace atmosphere have significant effects on the thermal expansion curves of the gypsum bonded investments. 2) One steep expansion and three stages of shrinkage in heating process of these investments from room temperature to about 900 degrees C were observed. 3) The quantity of the steep expansion, first and second stages of shrinkage and the expansion at 650 degrees C were affected by W/P ratio. 4) The temperature at which the steep expansion or shrinkage occurred were affected by heating rate. 5) Furnace atmosphere affected on both quantity of the steep expansion or shrinkage and their temperature. It also affected on the expansion at 650 degrees C. Then, these factors should be considered in dilatometry of gypsum bonded investments and in dental practice.

Calcium↗
PubMed1978

[Re-examination of dehydration process of gypsum by micro-DTA (author's transl)].

The results obtained by macro-DTA were not reproducible because they were largely influenced by the packing method, the amount of samples and many other factors related to each apparatus. The dehydration process of gypsum was investigated by micro-DTA in this study. The results were compared with those of macro-DTA studies. Two endothermic peaks were generally observed. These peaks tended to overlap with the increase of particle size. As the water vapor pressure decreased, the two peaks shifted to lower temperature and finally overlapped completely. The effect of the amount of samples was very similar to that of the atmosphere. When the amount was less than about 1 mg, only a single peak was observed. The dehydration process of gypsum was discussed on the basis of a phase diagram of the system of CaSO4-H2O. Moreover, the activation energies of the first and second dehydration reactions were calculated by Kissinger's method. The former was about 25 kcal/mol and the latter was about 24 kcal/mol. They werein good agreement with those obtained by other workers.

Calcium Sulfate↗
PubMed1977

Spastic paraplegia with neurogenic amyotrophy manifesting ballooned axons in sural nerve.

A 21-year-old man had progressive symmetric, distal muscle atrophy and weakness, as well as spasticity of the limbs. Histologic examination of the sural nerve disclosed swollen axons containing membranous tubular profiles, ring tubules, large mitochondria with abnormal cristae, and glycogen like granules. Peripheral sensory nerve fibers also were affected. The pathologic features of the peripheral nerves were similar to those of infantile neuroaxonal dystrophy. Sural nerve biopsy may be useful in the study of pathologic processes in spastic paraplegia.

Adult↗