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Biomedical subjects

K Noguchi

Publications and source records attributed to K Noguchi.

At least 541 records · Page 30Linked to original sources
PubMed1980

[Non-destructive neutron activation analysis of dental porcelain powders (author's transl)].

Determination of 15 elements in the dental porcelain powders (Vita VMK 68) marketed in Japan was done by means of non-destructive neutron activation analysis. The potassium and sodium contents showed less variations from powder to powder, and the uranium contents varied from a few ppm to 1090 ppm in a wide range. The high contents of uranium (345--1090 ppm) were detected in the powders of Enamel, Dentin, Effect, Color and Gum which were used for the superficial parts of a porcelain crown, while the low contents of uranium (1.6--2.7 ppm) were detected in those of Opaque and Translucent which were used for the core part and the top of the crown. Cerium and samarium were also detected in each powder in the amounts similar to those of uranium. The main radionuclides present in the porcelain powders were 238U, 235U, 234U, 234mPa, 234Th, 231Th and 40K. The activities of these nuclides were calculated and discussed.

Activation Analysis↗
PubMed1980

[Distribution of uranium in dental porcelains by means of the fission track method (author's transl)].

Porcelain teeth, some of which contain uranium compounds for aesthetic purpose, have been widely used in dental clinics. Hazardous effects due to uranium radiation have been suggested by recent publications. In the previous study, the authors reported the uranium content of porcelain teeth and radiation dose by it. In this study, using the fission track method, the authors examined spatial distribution of uranium in dental porcelain teeth (4 brands) which were marketed in Japan. From each sample of porcelain tooth, a 1-mm-thick specimen was sliced, and uranium content was measured at every 0.19 mm from labial side to lingual side for making a uranium distribution chart. Higher uranium concentration was found in Trubyte Bioblend porcelain teeth (USA) and they showed almost uniform distribution of uranium, while those of the Japanese three brands indicated, in most case, comparatively lower concentration and found to be non-uniform distributions. Range of uranium concentration in these brands were N.D. approximately 5.2 ppm (Shofu-Ace), N.D. approximately 342 ppm (Shofu-Real), N.D. approximately 47 ppm (G.C. Livdent) and N.D. approximately 235 ppm (Trubyte Bioblend), respectively.

Dental Porcelain↗
PubMed1980

Pluripotent hemopoietic precursors in vitro (CFUMIX) in aplastic anemia.

When human marrow cells were cultured in a medium containing alpha-medium, methylcellulose, fetal calf serum, bovine serum albumin, erythropoietin, and leucocyte-conditioned medium, mixed colonies composed of erythrocytic cells and granulocytes were formed. The clonal nature of the mixed colonies was confirmed by the linear relationship between the numbers of cells plated and the number of colonies, and the absence or presence of Y-chromatin in the mixed colonies in a co-culture experiment with male and female cells. Using the methylcellulose cell culture techniques, the pluripotent hemopoietic precursors (CFUMIX) in marrow cells from 15 patients with aplastic anemia were assayed. In the control subjects of patients with iron-deficiency anemia, lymphoadenitis, reactive leucocytosis or Hodgkin's disease, 8 X 10(5) marrow cells in 4 dishes produced 12.7 +/- 6.9 (mean +/- SD) mixed colonies. On the other hand, 8 X 10(5) marrow cells from patients with aplastic anemia formed only 2.1 +/- 5.5 (mean +/- SD) mixed colonies. Furthermore, the marrow cells from 5 patients who were repeatedly receiving transfusions contained no CFUMIX which give rise to mixed colonies. The present results provided the first direct evidence that pancytopenia in most patients with aplastic anemia results from a reduced influx into the compartment of maturing hemopoietic cells from the compartment of pluripotent hemopoietic precursors.

Adult↗
PubMed1979

Acute aortic regurgitation with congestive heart failure due to bacterial endocarditis: diagnosed by echocardiogram and treated successfully by surgery (a case report).

A 23-year-old Japanese male with no evidence of previous heart disease was presented with bicuspid aortic valve and a life threatening acute aortic regurgitation due to subacute bacterial endocarditis. By echocardiographic techniques, a precise diagnosis was made based on the following findings: 1) premature mitral valve closure, 2) snowfall-like echoes between the systolic aortic cusps, 3) eccentricity of a diastolic aortic valvular echo. The echocardiographic diagnosis was confirmed on surgery, in which aortic valve replacement was performed with satisfactory postoperative results.

Adult↗
PubMed1979

Growth behaviour of condylar cartilage and epiphyseal cartilage on the different medium of the organ culture.

In order to compare histological differences between the condylar and epiphyseal cartilages, an organ culture system was employed. Materials from 36 neonatal rabbits were cultured for 7 days on three different, chemically defined media (Ham F12, Medium 199, and Eagle's minimum essential medium) with the addition of various concentrations of ascorbic acid, fetal calf serum and NaHCO3. The epiphyseal cartilage was maintained in situ histological and biochemical features better than the condylar cartilage on any of the medium used. The maximum sensitivity to Toluidine Blue staining of the cultured condylar cartilage was observed on Ham F12. For both the condylar and epiphyseal cartilages, Ham F12 with the addition of 50 microgram/ml ascorbic acid and higher concentration of NaHCO3 was more effective on the maintenance of cell organization. However, effect of the addition of fetal calf serum to the medium was quite different between the condylar and epiphyseal cartilages, that is, the former showed better histological features without the addition, but the latter showed features similar to that in situ with 20% addition of fetal calf serum.

Animals↗
PubMed1979

Growth of condylar, epiphyseal and spheno-occipital synchrondrosal cartilages cultured on medium BGJ.

The purpose of this experiment was to examine the growth of condylar, epiphyseal, and spheno-occipital synchrondrosal cartilages cultured on medium BGJ. Materials from 12 neonatal rabbits were cultured for 7 days on this medium with the addition of 0, 10, or 20% fetal calf serum. Epiphyseal cartilages cultured with the addition of 20% fetal calf serum showed slightly better maintenance of in situ state, though little morphological changes were observed during 7 days. Spheno-occipital synchondrosal cartilages cultured with the addition of 10% or 20% fetal calf serum were histologically relatively similar to in situ state than those cultured without fetal calf serum, but no growth in length and width of these cartilages was observed. On the other hand, cultured condylar cartilages showed the least maintenance of histological and histochemical features. It was assumed that medium BGJ was not a recommendable medium for the organ culture of condylar cartilage.

Animals↗
PubMed1979

Mouse strain identification by means of discriminant analysis using mandible measurements.

Mouse strains were identified by the aid of discriminant functions obtained from discriminant analysis of values measured at 13 sites of the mandible. They consisted of nine inbred strains of mice, AA, DDD, DDK, DDY, DSD, KK, NC, RR, and SS, and one mutant strain, NC-brp, maintained exactly in the National Institute of Animal Health, Minstry of Agriculture, Forestry and Fisheries. As a result, the probability of erroneous discrimination was 1 head/246 head, or 0.41%, for the males and 2 head/238 head, or 0.84%, for the females. Therefore, almost all the mouse strains were identified correctly. These results seemed to indicate that the strains of mice would be identified more correctly than before, if the present method by the aid of discriminant functions was applied in addition to the methods of identification based on the coat color, biochemical marker-genes, and histocompatibility genes.

Animals↗
PubMed1978

Effect of chloramphenicol on colony formation from erythrocytic precursors.

In the present experiments, we compare the behavior of erythropoietic precursors and granulocytic precurosors exposed to chloramphenicol. Subcutaneous injection of 20 mg of chloramphenicol sodium succinate on five successive days induced a reduction in the number of erythrocytic colony-forming units (CFU-E) and erythropoietic burst-forming units (BFU-E) in murine marrow and spleen, while no change in number of granulocytic precursors (CFU-C) in murine hemopoietic organs was observed. In vitro studies demonstrated concentration-dependent inhibition of chloramphenicol or chloramphenicol sodium succinate in the colony formatin of all these precursors from murine and human bone marrow. However, erythropoietic burst formation of murine and human BFU-E was completely suppressed by the addition of chloramphenicol or chloramphenicol sodium succinate to the culture medium at therapeutic concentrations (20--40 microgram/ml). From the present results, it can be concluded that the reduced number of BFU-E in mice after injection of chloramphenicol sodium succinate resulted from the selective toxicity of chloramphenicol to BFU-E at therapeutic concentrations.

Animals↗