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Biomedical subjects

H Tsuzuki

Publications and source records attributed to H Tsuzuki.

At least 109 records · Page 6Linked to original sources
PubMed1979

Pepstatin-insenstive acid proteases from Scytalidium lignicolum. Kinetic study with synthetic peptides.

A kinetic study was conducted on the acid proteases A-1 and A-2 from Scytalidium lignicolum using synthetic peptides as substrates. Almost maximum activity was attained with N-acylated tetrapeptides as the molecular size of substrates was increased. Suitable amino acid residues were required at the P1-P2 and P1'-P2' positions [notation of Schechter and Berger (14)]. Hydrophobic or bulky residues such as leucine were specifically required at the P1 and P1' positions, with the specificity at the latter position being considerably lower than that at the former. For catalysis, the presence of certain amino acid residues at the P2 and P2' positions was essential, mainly in relation to kcat. An inhibition study supported this view. Stringent stereospecificity was observed at the P2 and P2' positions, but the side chain specificity was low. Study of the B enzyme from the same organism was very difficult owing to its low activity against the peptides used. The Scytalidium acid proteases A-1, A-2, and B showed considerably different behavior against peptide substrates in comparison with usual acid proteases, which are senstive to pepstatin.

Aspergillus niger↗
PubMed1978

Paroxysmal discharges triggered by hearing spoken language.

We examined the modality of EEG activation by various kinds of acoustic stimulation in a middle-aged Japanese female with epilepsy. Paroxysmal discharges were triggered in the right frontal area (F4) by verval stimulation. For the activation of EEG, concentration of attention on the stimulation was essential; therefore paroxysmal discharges were triggered most easily by verbal stimuli when someone spoke to the patient directly. Stronger responses than usual were triggered by specific words, and apparently reflected the interest and concern of the patient. The latency from stimulation to paroxysmal discharges ranged from 230 to 1,300 msec, suggesting that the responses may have been a function of the perception and recognition of acoustic stimuli. "Heard-word epilepsy" or "Angesprochene Epilepsie" is suggested in this case.

Acoustic Stimulation↗
PubMed1978

Effectiveness of immunization with single and multi-component vaccines prepared from a common antigen (OEP), protease and elastase toxoids of Pseudomonas aeruginosa on protection against hemorrhagic pneumonia in mink due to P. aeruginosa.

Toxoids of protease and elastase of Pseudomonas aeruginosa were successfully prepared by treatment with 8% formalin plus 0.2 m lysine and by 4% formalin respectively. The two toxoids proved sufficiently potent to elicit high antibody titers as estimated by both the enzyme-neutralizing and passive hemagglutination tests. The effectiveness of immunizing minks with a single component-vaccine consisting of the common antigen (OEP) of P. aeruginosa or the protease toxoid (PT) or the elastase toxoid (ET) and with the two (PT and ET) or the three (OEP, PT and ET) component-mixed vaccines, on hemorrhagic pneumonia in minks due to the bacteria was investigated. Female Sapphire minks, 3.5 months old, were used in two experiments performed in 1975 and 1976. Minks were immunized three times in one month with a total of 1 mg of each of the three antigens in the case of a single component vaccine and with a total of 2 or 3 mg (equal amounts of each component) in the case of the two or three component vaccines. Two or three weeks after the last immunization, challenge exposure with strain No. 5 was carried out by intranasally inoculating an inoculum containing serial dilutions of 10(3) -10(10) of live bacteria. Summarizing the results of the two experiments, in the case of controls, nonimmunized minks and minks immunized with potassium aluminum sulfate (potash alum) alone, the LD50 values were approximately 10(3) -10(4) with no significant difference between the two. In the case of OEP-vaccinated minks, the LD50 value was about 10(6) and thus clearly differed from those of the controls. In minks immunized with the three-component-vaccine, however, the LD50 value was about 10(8) -10(9), which indicated that the three-component-mixed vaccine was remarkably more effective than the single OEP vaccine component. In minks immunized with either PT or ET or both, the LD50 values were about 10(8) -10(9). The effectiveness of the vaccine made with ET or PT alone is discussed in the text. The pathological findings of the minks which died or survived are described.

Animals↗
PubMed1977

Production of protease and elastase by Pseudomonas aeruginosa strains isolated from patients.

Using 20 strains of Pseudomonas aeruginosa isolated from patients, production of protease, elastase, and collagenase was determined by shaking culture in either complex or semisynthetic medium. No collagenase was produced by any strain of P. aeruginosa. According to their production of protease and elastase in different media, the P. aeruginosa strains were divided into three groups: the first group can produce elastase in complex medium and both protease and elastase in semisynthetic medium; the second group cannot produce any proteolytic enzymes in complex medium but can produce any proteolytic enzymes in either medium; and the third group cannot produce any proteolytic enzymes in either medium. In spite of the differences in the ability of the strains to produce the enzymes, depending upon the origin of the strains, the protease or elastases produced in different broths were regarded as identical.

Caseins↗