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Biomedical subjects

K Ohta

Publications and source records attributed to K Ohta.

At least 883 records · Page 49Linked to original sources
PubMed1980

Effects of oral feeding of mite antigen upon production of homocytotropic antibodies.

Effect of oral administration of mite antigen was studied in homocytotropic antibody production in mice. Anti-mite IgE and IgG, antibodies were undetectable if the large amount of mite antigen was given prior to primary immunization. It was noted that the larger the dosage given the more clearly the suppression of homocytotropic antibody production was obtained and the shorter the interval between feeding and primary immunization the more marked tolerance was induced. No significant effect was observed by oral administration of antigen in on-going homocytotropic antibodies.

Aging↗
PubMed1979

A gas chromatographic-mass spectrometric assay for nine hydroxyphenolic acids in uremic serum.

A mass fragmentographic method for the determination of m-hydroxybenzoic acid, p-hydroxybenzoic acid, o-hydroxyphenylacetic acid, m-hydroxyphenylacetic acid, p-hydroxyphenylacetic acid, vanillic acid, p-hydroxymandelic acid, homovanillic acid and vanilmandelic acid in uremic serum is described. The hydroxyphenolic acids were extracted from one ml of serum ultrafiltrate. After trimethylsilylation, the extract was analyzed by a gas chromatograph-mass spectrometer. Concentrations of nine hydroxyphenolic acids are higher in uremic serum. In particular, p-hydroxybenzoic acid and p-hydroxyphenylacetic acid are markedly increased in uremic serum. The influence of hemodialysis on the hydroxyphenolic acids was studied by quantitating the acids before and after hemodialysis.

Female↗
PubMed1979

Ion-exchange chromatographic separation and fluorometric detection of guanidino compounds in physiologic fluids.

A high-performance liquid chromatographic procedure has been developed for the separation and fluorometric detection of guanidino compounds in physiologic fluids. All guanidino compounds were separated on a 17 X 0.46 cm cation-exchange column using a stepwise pH gradient. The chromatographic system was designed to enable the use of the specific reagent 9,10-phenanthrenequinone as a means of monitoring the guanidino compounds of physiologic fluids. This new analytical method is so sensitive that it enables the analysis at the picomole level. Our automatic guanidino-compound analyzer was successfully applied to the quantitative determination of all guanidino compounds in physiologic fluids from normal controls and uremic patients.

Autoanalysis↗
PubMed1979

Quantitative analysis of methylguanidine and guanidine in physiologic fluids by high-performance liquid chromatography-fluorescence detection method.

A rapid and sensitive high-performance liquid chromatographic method has been developed for the quantitative analysis of methylguanidine and guanidine in physiological fluids. These quanidino compounds are separated on a 6 x 0.23 cm cation-exchange column with 0.5 M sodium hydroxide solution. The guanidino compounds are detected with a fluorometer, which monitors the fluorescent guanidine derivatives produced by the reaction of the eluted constituents with 9,10-phenanthrenequinone. Sensitivity to sub-nanomole levels of methylguanidine and guanidine is demonstrated. The method was successfully applied to physiological fluids such as serum and cerebrospinal fluid from uremic patients.

Chromatography, High Pressure Liquid↗
PubMed1979

Lafora-like bodies in a cat. Case report suggestive of glycogen metabolism disturbances.

Lafora-like bodies in an 8-year-old cat were studied light and electron microscopically and histochemically. In addition ot Lafora-like bodies composed of branching filaments, glycogen granules and electron-dense materaisl, abnormal accumulations of glycogen granules attracted attention. The most remarkable features were the developmental processes of the branching filaments originating directly from glycogen granules. Lafora-like bodies in the present study showed ultrastructural, histochemical, and enzymatic similarities to those described in the previous reports in Lafora's disease, glycogenosm is considered to be probably related to the productive mechanism of Lafora-like bodies.

Animals↗
PubMed1979

Correlative studies of axonal spheroids and Lafora-like bodies in aged dogs.

The gracile nucleus and conus medullaris, the sites of predilection for spheroids and Lafora-like bodies, were examined light and electron microscopically in 91 dogs ranging from 1 month to 19 years of age. The number of both structures showed a tendency to increase with age. Spheroids have already been found in younger dogs before the appearance of Lafora-like bodies. In the aged dog, intra-spheroidal Lafora-like bodies were occasionally observed. Correlative studies may yield clues on the pathogenesis of aging phenomena in the CNS.

Aging↗
PubMed1979

Production of prostacyclin-like substance in stroke-prone and stroke-resistant spontaneously hypertensive rats.

Activities of aortae to produce prostaglandin (PG) I2-like substance in stroke-prone spontaneously hypertensive rats (SHRSP), stroke-resistant SHR (SHRSR) and normotensive control rats from the Wistar-Kyoto (WK) colony were compared. PGI2-like substance was produced by the incubation of the aortic ring in pH 9.0 borate-buffered saline and the amount produced was estimated by comparison of its anti-aggregatory activity with that produced by known amounts of the sodium salt of synthetic PGI2. Before the development of stroke, amounts of this substance generated in SHRSP and SHRSR were significantly higher than those in WK rats (p less than 0.01 and p less than 0.02, respectively). Remarkably reduced capacity to generate PGI2-like substance was observed in some SHRSP after the development of stroke.

Animals↗
PubMed1979

Biochemical alterations of connective tissue metabolism in the arterial walls of stroke-prone spontaneously hypertensive rats.

1. The chemical characteristics of the vascular connective tissue components were determined in stroke-prone (SP), stroke-resistant (SR) spontaneously hypertensive (SH) rats and normotensive Wistar-Kyoto (WK) rats. 2. The ratio of hydroxylysine to hydroxylsine plus lysine in the vascular collagen was increased in 6-month-old SP-SH rats and SR-SH rats as compared with WK rats. 3. An age-related increase in uronic acid and hexose content of the aorta was noted in SP-SH, SR-SH and WK rats. However, the increase was more prominent in SH rats, especially SP-SH rats at the stages examined (11 weeks and over 8 months of age). 4. The ratio of galactosyl-hydroxylysine to glucosyl-galactosyl-hydroxylysine in the aortic collagen was decreased in 6-month-old SH rats, especially SP-SH rats as compared with WK rats. 5. A relative increase in beta and gamma components in aortic collagen was noted in 6-month-old SP-SH rats when compared with SR-SH rats. 6. The increased content of uronic acid and hexose and the structural changes of vascular collagen as demonstrated in SP-SH rats might be related to the fragility of the arterial wall and/or to the pathogenesis of stroke-proneness.

Aging↗
PubMed1979

Problems with activated charcoal and alumina as sorbents for medical use.

Although activated charcoal and alumina have been used extensively as sorbents in uremic patients, the following problems remain to be solved: 1) elution of SO4--from activated charcoal which does not adsorb it; 2) production of methylguanidine from creatinine on the surface of activated charcoal; 3) production of lipoperoxide from fatty acids by chemical reaction of activated charcoal; 4) adsorption of Ca++ and Mg++ when alumina adsorbs inorganic phosphate. These problems are studied in vitro and clinically.

Adsorption↗
PubMed1979

Chemical analysis of vascular collagen in stroke-prone spontaneously hypertensive rats.

Chemical characteristics of vascular collagen were studied in stroke-prone spontaneously hypertensive rats (SHRSP) which developed cerebrovascular lesions spontaneously in over 90% of the population. Aminoacid analysis of arterial collagen among SHRSP showed no remarkable difference from stroke-resistant SHR (SHRSR) and normotensive Wistar-Kyoto rats (WK). The uronic acid content of the aorta, which elevated with aging, was increased in SHRSR and especially in SHRSP. The hexose content of collagen was also increased in SHRSP characteristically with a concomitant increase in the ratio of the disaccharide unit (glucosyl-galactosyl-hydroxylysine) to the monosaccharide (galactosyl-hydroxylysine). The relative increase in beta and gamma components was also noted in SHRSP. These structural changes of vascular collagen especially noted in SHRSP may be related to the fragility of arterial wall or to the stroke-proneness.

Amino Acids↗