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Biomedical subjects

K Okazaki

Publications and source records attributed to K Okazaki.

At least 451 records · Page 25Linked to original sources
PubMed1980

[Studies on Au-Ag-Pd-Cu alloys. (Part 2) Some properties on alloys containing 30 wt% Au (author's transl)].

In the previous paper, the author reported 30 wt% Au was more favourable content in Au-Ag-Pd-Cu quaternary dental alloys. In this paper, the experiment was carried out to find suitable Pd and Cu content in 30 wt% Au-Ag-Pd-Cu alloy. Pd and Cu content was changed from 5 wt% to 25 wt% and from 10 wt% to 20 wt% respectively. Ag content was balanced, and no other metals was added. Range of solidification temperature, tensile strength, elongation, hardness, corrosion resistivity and castability were tested. Results were as follows. 1) In these alloys, liquidus points were in the range of 880 degree C approximately 140 degree C, but in the majority of alloys, liquidus points were under 1100 degree C. Range of solidification temperature was more narrow in 20 wt% Cu than other Cu content. 2) The tensile strength and elongation of swaged specimens increased as Pd content increased, but in case of cast specimens, mechanical properties were the highest at 15 approximately 20 wt% Pd. The Vicker's hardness was in the range of 116 to 235. 3) The corrosion test in 0.1% Na2S solution indicated that the corrosion resistance was increased with Pd content and alloys contained more than 20 wt% Pd showed good resistance to corrosion. 4) The castability was affected by the Pd content and much decreased between 15 wt% Pd and 20 wt% Pd, but the castability of these alloys is twice as good as the alloys on the market. From these results, it seemed that the alloys containing 15 approximately 20 wt% Pd and 15 approximately 25 wt% Cu were more favourable composition to 30 wt% Au-Ag-Pd-Cu alloys.

Copper↗
PubMed1979

Effect of actinomycin D on the expression of herpes simplex virus-common surface antigen in cells transformed by herpes simplex virus type 2.

Using rabbit antiserum hyperimmune to herpes simplex virus (HSV) type 1, the expression of HSV-common surface antigen(s) was studied by indirect immunofluorescence tests in cells transformed by HSV type 2 and in derived tumor cells. The following results were obtained. (i) Antiserum to HSV type 1 reacted specifically with surface antigen present on the plasma membrane of both HSV type 2-infected and HSV type 2-transformed hamster cells. (ii) The expression of this antigen was enhanced in the absence of active protein synthesis in transformed cells, but not in tumor cells, after culture for 3 to 5 h at 37 degrees C. (iii) This enhancement of expression was maintained for 20 h in the presence of actinomycin D, but this prolonged expression required active protein synthesis. (iv) The enhancing effect observed in the presence of actinomycin D continued for some time after removal of the drug, for example, for 20 h after 5 h of treatment with 2 microgram/ml of actinomycin D per ml. Actinomycin D had no detectable effect on antigen expression in tumor cells. (v) The protease inhibitor antipain inhibited the actinomycin D-enhanced expression without causing significant cell damage but did not modify the transient enhanced expression of antigen when cells were seeded in the absence of actinomycin D. These results indicate that in transformed cells antigen expression can be enhanced in at least two ways.

Antigens, Surface↗
PubMed1979

[Studies on Au-Ag-Pd-Cu alloys. (Part 1) Effects of Au component on some properties of alloys (author's transl)].

Au-Ag-Pd-Cu quaternary dental alloys were studied to find out the more favourable Au content. Pd and Cu content were fixed to 20 wt% respectively but Au content were changed from 10 wt% to 40 wt% and Ag content were balanced. Tensile, hardness, corrosion and castability test were carried out. Results were as follows. 1) The tensile strength and elongation of swaged specimen showed highest value at 30 wt% Au but in case of casted specimen, tensile strength was highest as 20 wt% and elongation was minimum at 30 wt% Au. Those differences between swaged and cast specimens were seemed to depend on the casting porosities. 2) The Vickers hardness test showed that the hardness gradually increased with Au content and showed the highest value at 30 wt% Au. 3) The corrosion test in the 0.1% Na2S solution indicated that the corrosion resistance was increased with Au content but the rate of increment was slow down at 30 wt% Au. 4) The castability test showed that no significant difference was found out one another. These experimental results seemed to indicate that 30 wt% Au was the favourable composition for Au-Ag-Pd-Cu dental alloys.

Copper↗
PubMed1978

Enflurane-induced hypotension modifies transmural blood flow distribution in the canine left ventricle.

Coronary and systemic circulations, and contractility and oxygen consumption of the left ventricular myocardium were depressed as arterial enflurane concentration increased in acute experiments with 22 adult mongrel dogs. Uneven transmural blood flow in the left ventricular free wall did not appear and the inner/outer ratio remained near 1.0 until a very deep stage of the anesthesia was attained and as far as diastolic aortic pressure was maintained above 40 mmHg, according to the microsphere injection study. Once diastolic pressure fell below 35--40 mmHg, the ratios started to be reduced significantly. When arterial enflurane content reached 53.0 +/- 2.1 mg/100 ml (mean +/- s.e.), the ratio became 0.84 +/- 0.08 (p less than 0.001), and simultaneously calculated DPTI/TTI ratio also showed a significant redution from the control (0.79 +/- 0.03, p less than 0.001). The I/O and DPTI/TTI ratios, however, did not correlate significantly with each other until very deep enflurane anesthesia was attained. The lower limit of autoregulation of coronary vascular bed was suggested to be near 35--40 mmHg of diastolic aortic pressure during deep enflurane anesthesia in the dog. Among systolic time intervals measured directly during the study, PEP and ICT showed significant negative correlations with Vmax and LV dp/dt max, while LVET neither changed nor correlated significantly with stroke volume or other parameters representing myocardial contractility during the course of enflurane anesthesia.

Animals↗
PubMed1978

Therapeutic value of mepitiostane in the treatment of advanced breast cancer.

A new, orally active antiestrogenic steroid, mepitiostane (20 mg/day), was given to 45 patients with advanced breast cancer. The regression rate was 31.1%, or 14 of 45 patients, and a duration of regression of greater than 6 months was obtained in seven patients. Virilizing effects such as hoarseness, hirsutism, and acne were observed relatively often, but there was no evidence of abnormality in the liver function tests or in the serum calcium level.

Androstanes↗