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Biomedical subjects

I Kato

Publications and source records attributed to I Kato.

At least 631 records · Page 35Linked to original sources
PubMed1980

Crystallization and properties of staphylococcal leukocidin.

Two components (F and S) of leukocidin were isolated and purified from broth culture of V8 strain of Staphylococcus aureus. There was loss of leukocidin activity during the separation, which was regained by mixing the components. Each component was apparently homogeneous by several criteria. The F and S components were crystallized (by salting out with saturated (NH4)2SO4 at pH 7.0) in the form of square plates and very fine needles, respectively, and the molecular weights of the components were approx. 32 000 and 31 000, respectively. The isoelectric points of the F and S components were pH 9.08 and 9.39, respectively. No detectable half-cystine and free sulfhydryl groups were found in either component. Amino-terminal amino acid analysis of both components showed a single alanine residue. The F and S components of leukocidin acted synergistically on granulocytes from rabbit peripheral blood and a minimum lethal dose of 0.5 ng of each component destroyed all granulocytes at a concentration of 10(6) cells/20 microliter.

Amino Acids↗
PubMed1980

A Ser162/Gly162 polymorphism in Japanese quail ovomucoid.

Japanese quail ovomucoid exists in two polymorphic forms. One has serine, the other glycine at position 162. The tryptic peptide corresponding to positions 160 to 164 was purified from ovomucoids isolated from egg whites of eggs laid by 11 different hens and subjected to amino acid analysis. The quantitative distribution of serine and glycine in this pentapeptide is consistent with the interpretation that the ovomucoid gene exists in two codominant allelic forms at one locus. Even though the gene product is apparently expressed only in the female, these results indicate that the ovomucoid structural gene is transmitted as a simple Mendelian character which is neither sex-linked nor shows dominance. Intact third domains (positions 131 to 186) isolated from the two allelic forms of ovomucoid interact with bovine beta-trypsin in a similar but not identical manner; the complex with the glycine form dissociates more rapidly. Evidence is presented which suggests that glycine is the ancestral residue at position 162; yet, the serine form is the more frequent phenotype.

Amino Acids↗
PubMed1980

Failure of fixation suppression of caloric nystagmus and ocular motor abnormalities.

Caloric nystagmus is substantially suppressed by visual fixation. The degree of suppression of caloric nystagmus is influenced by the condition of visual fixation. We studied the percent reduction in slow-phase velocity of caloric nystagmus by visual fixation and certain abnormalities in optokinetic nystagmus, smooth pursuit, and maintenance of ocular position of gaze in 38 patients with disorders of the CNS. The inability to suppress caloric nystagmus by visual fixation correlated with reduction in optokinetic nystagmus, deficit in smooth pursuit eye movements, and presence of gaze nystagmus. It seems probable that modulation of the vestibulo-ocular reflex is influenced by the same mechanisms that are concerned with optokinetic nystagmus, maintenance of ocular position of gaze, and smooth pursuit eye movements.

Brain Diseases↗
PubMed1980

Fixation and inactivation of staphylococcal leukocidin by phosphatidylcholine and ganglioside GM1 in rabbit polymorphonuclear leukocytes.

Staphylococcal leukocidin is resolved by chromatography on carboxymethyl cellulose columns into two components, which are designated F (fast) and S (slow). Fixation and inactivation of both components were studied as follows. (i) Leukocidin activity was confined to the first 10 min of intoxication, and the maximal effect resulted from treating 10(6) rabbit peripheral polymorphonuclear leukocytes per 20 mul with 0.5 ng of each component of leukocidin. The S component was more responsible for the interaction with the leukocytes than the F component. (ii) The F component was inactivated by phosphatidylcholine at concentrations which corresponded to molar proportions of 1:1 and bound to [(14)C]phosphatidylcholine at equimolar proportions. (iii) The S component was inactivated by ganglioside G(M1) at 1:1 molar proportions, but not by any of the related glycolipids. Ganglioside G(M1) also was precipitated with the S component by a gel diffusion technique. Subunit B of cholera toxin competitively inhibited the binding of the S component to rabbit leukocyte membranes. This indicates that ganglioside G(M1) may resemble or be part of the receptor site for the S component.

Animals↗
PubMed1980

Action of rennin on casein. III. Effect of alpha s- and beta-casein on the secondary phase.

The action of rennin on kappa-casein was studied as a function of time, employing turbidity measurements at 610 nm and the release of nonprotein nitrogen. kappa-Casein was converted to para-kappa-casein by the action of rennin. The para-kappa-casein aggregated to increase turbidity and then precipitated. Turbidity development was enhanced initially and then retarded severely by increasing concentrations of added alpha s- and beta-casein. The addition of selected amino acids and salts had variable effects on increase of turbidity.

Amino Acids↗
PubMed1979

Inhibitory effect of a lethal toxic fragment of staphylococcal alpha-toxin on cyclic AMP-dependent protein kinase activity.

The effect of a lethal toxic fragment of staphylococcal alpha-toxin on the activity of adenosine 3',5'-monophosphate(cyclic AMP)-dependent protein kinase was examined. 1. The lethal toxic fragment produced a dose-dependent decrease in both the binding of cyclic AMP to the regulatory subunit and phosphorylation activity of cyclic AMP-dependent protein kinase obtained from rabbit skeletal muscles up to a plateau at a 50% inhibitory effect. The decrease in the activity of protein kinase observed with low doses of the lethal toxic fragment (0.1 microM) resulted from a competitive inhibition, probably by its interaction with the cyclic AMP-binding site in the regulatory subunit molecule. 2. The effects of a lethal toxic fragment and epinephrine on the cyclic AMP level and protein kinase activity were investigated in the perfused rabbit heart slices. The lethal toxic fragment attenuated the stimulation of cyclic AMP-dependent protein kinase activity ratio by epinephrine. 3. It is suggested that the specific action of a lethal toxic fragment on the cellular membrane enzymes may be attributable to the inhibition of the cyclic AMP-dependent protein kinase activity.

Animals↗
PubMed1979

Epidemiological survey of definite cases of Meniere's disease collected by the seventeen members of the Meniere's Disease Research Committee of Japan in 1975--1976.

Between Aril 1975 and December 1976, the second nationwide survey of Meniere's disease in Japan was made by the 17 members of the Meniere's Disease Research Committee of Japan. The epidemiological data from 520 patients with definite Meniere's disease were analyzed in comparison with those from the 126 patients in the non-Meniere vertiginous group (Control A) and the 228 patients in the rhinolaryngological group (Control B). The male:female ratio of definite cases of Meniere's disease was almost the same, and the age distribution peaked at the age group of 40--49 years for males, while the peak for females was at the age group of 30--39 years. 5.8% of the 520 patients had a close relative who also suffered from Meniere's disease. From the epidemiological features, it may appear that the occurrence of vertiginous attacks in Meniere's disease is influenced much more by individual than by environmental factors. However, this feature can be considered as another evidence of the psychosomatic disorders involved in Meniere's disease.

Age Factors↗