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Biomedical subjects

T Nishimura

Publications and source records attributed to T Nishimura.

At least 1,531 records · Page 85Linked to original sources
PubMed1981

Fracture process in tensile testing dental Ni-base casting alloys.

Early-fracture in tensile specimens was found in Ni-base casting alloys which were obtained in conventional casting condition. In 32 Ni-23 Cu-25 Mn alloy, intercrystalline fracture occurred in both early-fractured and normal ductile specimens. On the contrary, intercrystalline and innercrystalline fracture were, respectively, found in early-fractured and normal samples. As the fracture process, voids formed by stress-concentration around A-grain and brittle fracture of soft B-grain in 32 Ni-23 Cu-25 Mn alloy, while voids occurred by stress-concentration around inclusion as chromium carbide and slip deformation on the maximum shear stress plane in 84 Ni-9 Cr alloy.

Dental Alloys↗
PubMed1981

[Laboratory and clinical studies of cefadroxil (author's transl)].

The authors have carried out the laboratory and clinical studies of cefadroxil (CDX). The results were as follows; The sensitivity was measured by plate dilution method on 27 strains of S. aureus and E. coli, 26 strains of K. pneumoniae isolated from patients. The distribution of sensitivity of S. aureus was 3.13-12.5 microgram/ml and the peak of distribution was 3.13 microgram/ml and 6.25 microgram/ml, of E. coli was 6.25 microgram/ml by 10(8) cells/ml. And the distribution of sensitivity of K. pneumoniae was 6.25-25 microgram/ml and its peak was 6.25 microgram/ml by 10(8) cells/ml. CDX were given orally at dose of 10 mg/kg to 3 children. The serum levels of CDX were 10.5 +/- 1.78 microgram/ml, 15.8 +/- 3.25 microgram/ml, 12.0 +/- 0.41 microgram/ml and 3.9 +/- 0.9 microgram/ml at 0.5, 1, 2, 4 hours after administration respectively, and was 2.3 +/- 0.48 microgram/ml at 6 hours. The urinary excretion rate was 55.6% up to 8 hours after administration. CDX were administered to 39 cases of pediatric infectious disease (26 cases with tonsillitis, 5 cases with enterocolitis, 3 cases with UTI, 2 cases with impetigo, each one case with bronchitis, cervical lymphadenitis and epididymitis). And CDX were given 25.0-65.2 mg/kg daily. Clinical results obtained were above good in all cases. No side effects were observed in any cases, except for one case, with diarrhea, 6 cases with the elevation of serum transaminase and 1 case with eosinophilia.

Bacterial Infections↗
PubMed1981

[Echocardiographic features of false tendons: with special reference to phonocardiographic significance (author's transl)].

Echocardiographic features consistent with the findings of false tendons (FTs) were described in five out of 1,000 consecutive cases, and they were studied in order to determine whether FT was responsible for the systolic murmurs. Three had heart diseases including aortic regurgitation, 3 degrees AV-block with aortic regurgitation, and pericarditis and mitral stenosis, and the remainder cases had no heart disease. M-mode echocardiograms showed abnormal linear echoes in the outflow tract of the left ventricle in three cases, and in the left ventricle toward the apex in another two cases. Two-dimensional echocardiograms revealed long string-like echoes stretching from the upper parts of the interventricular septum across the ventricular cavity to the lateral wall of the left ventricle in three cases in the long and short axis views or four chamber view. In another two cases, there were long slender echoes binding the lower parts of the interventricular septum and the left ventricle in the apical view. These string-like echoes seemed to represent FTs reported previously in autopsy cases. Phonocardiography with pharmacological study (amyl nitrite and methoxamine) showed no significant systolic murmur, for which Fts had been considered to be responsible, even in a dilated left ventricle. We conclude that (1) M-mode and two-dimensional echocardiograms can demonstrate the presence of FTs, (2) two-dimensional echocardiograms might be utilized in differentiating FTs from other abnormal linear echoes in the outflow tract of the left ventricle seen in M-mode echograms, and (3) FTs do not necessarily cause systolic murmur.

Adult↗
PubMed1981

[Scanning electron microscopic observations of microcorrosion casts for rabbit ovarian vasculature before ovulatory stimulus (author's transl)].

Ovarian vasculature of juvenile and adult rabbits was studied using a method of resin injection-corrosion casts. Arteries and arterioles in the ovarian stroma and capillary networks surrounding the follicles were observed on a three dimensional scale by scanning electron microscopy with the following findings: 1) The strongly coiled arteries are observed in adult rabbit ovaries. The first order arterioles arise from the spiral artery, and the second order arterioles stemming from these first order arterioles enter into each follicle. 2) Vasculature of follicles starts as glove-finger-like ramified capillary networks. As follicles grow, follicular vessels increase remarkably and form multilayered complex vascular networks surrounding the follicles. 3) The observations of circular impressions around the arterioles near the follicle and in the follicular wall suggest the existence of sphincteric control mechanism of blood flow into the follicle. 4) There are several pathways of venous drainage from a wall of large follicle and arterio-venous shunts are observed in the wall of such follicles. These structures may exert an important effect upon the follicular hemodynamics in the process of follicle rupture.

Animals↗
PubMed1981

Oscillation of membrane potential in syncytiotrophoblast of human term placenta in culture.

The membrane potentials and resistances of the cultured syncytiotrophoblast of human chorionic villi obtained from normal term placentas were measured using a standard electrophysiological technique. The mean value of membrane potentials and resistances for 156 cells in the control tris-buffered saline at 37 degrees C were -40.0 +/- 1.2 mV and 8.6 +/- 0.7 M omega (mean +/- S.E.), respectively. The membrane potential was markedly affected by the change of external concentration of Ca++ or K+. In 32 cells among 156 cells examined, spontaneous oscillations of membrane potentials were observed. They oscillated between around -38 mV and -57 mV with the average frequency of 2.4 +/- 0.2 times per minute, accompanied by decrease in membrane resistance on each hyperpolarization. Although oscillations of membrane potentials have been observed in other cultured cells, this is the first report on the oscillation of membrane potential in the human trophoblast.

Cells, Cultured↗
PubMed1981

[Histological studies of multiple subperitoneal nodules produced by prolonged administration of estrogen (author's transl)].

It has been reported that multiple peritoneal fibroids were produced in guinea pigs treated with large doses of estrogens, and the nodules regressed when the steroid stimulant was discontinued. Recently, these experimental nodules were considered to be simulating the disseminated pattern of Leiomyomatosis Peritonealis Disseminata (LPD). Although these experimental nodules were considered to be composed of fibroblasts by light-microscopic studies, LPD was verified to be composed of smooth muscle by electronmicroscopic studies. Therefore, it is indispensable to study these experimental nodules by electronmicroscopy, when we discuss about the similarities between experimental nodules and LPD. Guinea pigs were treated with various doses of estradiol benzoate (E) [40, 80, 100, 200 microgram/day, thrice a week, intramuscular injection]. After treatment for three months, every dose of E produced the lesions simulating the disseminated pattern of LPD: multiple nodules in various sizes, scattered on the surface of the uterine horn, peritoneum, spleen and pancreas, and in the omentum and mesocolon. Ultrastructurally, the nodules were composed of the cells resembling fibroblast. We conjectured that estrogen differentiates and proliferates the cells of the features of fibroblast-like cells from subcoelomic mesenchyme, resulting in the production of multiple superitoneal nodules simulating the disseminated pattern of LPD.

Animals↗
PubMed1981

[Ultrastructural observation of the ovulatory changes in the capillary of the human follicular apex (author's transl)].

To clarify its possible participation and mode of action in follicle rupture at human ovulation, the capillary in the apex of the ovarian follicle was investigated electronmicroscopically with 16 human ovaries. In the follicle at the mid-proliferative phase with 6 mm diameter, capillary lumen was narrow and empty. Capillary vessels observed in the theca interna of the preovulatory follicle were dilated and filled with blood cells. Their endothelial cells had indented nuclei and elongated thin cytoplasm with unusually irregular membranous protrusions. In cytoplasm there were numerous vesicles, some of which had fine granule-like contents of low electron density to be released into extracapillary space. These results indicate increased capillary permeability due to active transport around the time of ovulation. Polymorphonuclear leucocytes, rich in specific granules containing collagenase activity, were often observed in the capillary lumen as well as extracapillary space only close to the time of ovulation. This observation implies possible roles of leucocytes in collagen degradation. The present ultrastructural results suggest that the vast capillary network in the follicle wall plays an important role in the mechanism of follicle rupture through its increased permeability and collagenolytic activities of leucocytes.

Adult↗
PubMed1981

Evidence for receptor-dependent response to dihydrotestosterone in cultured human fibroblasts.

The effect of dihydrotestosterone on the production of proteins and collagen and the synthesis of DNA was studied in cultured fibroblasts obtained from a normal woman and from a patient with complete testicular feminization. The concentration of dihydrotestosterone binding sites in fibroblasts from vulvar skin of a normal woman and from perineal skin of a patient with complete testicular feminization was 35.9 +/- 1.7 fmoles/mg protein and 4.61 +/- 0.37 fmoles/mg protein, respectively. The apparent dissociation constant was 0.24 +/- 0.015 nM for fibroblasts from a normal woman and 0.21 +/- 0.031 nM for fibroblasts from a patient with complete testicular feminization. Fibroblasts grown to confluence were exposed to DHT in the concentrations of 10, 100 and 1000 ng/ml of the culture medium and cultures were maintained for up to six days thereafter. These hormone treatments brought about a significant elevation in the production of proteins and collagen by fibroblasts from a normal woman but failed to produce any perceivable changes in fibroblasts from a patient with complete testicular feminization. The synthesis of DNA in fibroblasts from either subject was unaffected by hormone treatment. These results suggest that augmented production of proteins and collagen in cultured human fibroblasts which follows stimulation by dihydrotestosterone occurs via a receptor system.

Adult↗
PubMed1981

[Myocardial imaging with thallium -201 in the patients with coronary involvement after Kawasaki disease (author's transl)].

Coronary cine-angiography (CAG) was performed in 290 cases with the history of Kawasaki disease, in whom 57 cases (19.6%) were found to have coronary involvements. In 42 out of these 57 cases, myocardial imaging with thallium-201 (201Tl) was performed, and abnormal findings were seen in 6 cases. Five of these 6 cases showed not only coronary aneurysms, but also coronary obstructive lesions on CAG, while the remaining case showed only coronary aneurysms. The decrease of the uptake of 201Tl by the myocardium appeared to be mainly due to the decrease of regional myocardial blood flow, especially in those cases with obstructive lesions. Myocardial imaging with 201Tl seems to be more sensitive than stress electrocardiography by treadmill to detect myocardial ischemia in the patients with coronary obstructive lesions, although it seems less sensitive than stress electrocardiography to detect coronary arterial stenosis.

Adolescent↗
PubMed1981

[Histological and histochemical changes of tracheal secretory cells following bromhexine treatment (author's transl)].

The effects of bromhexine, a mucolytic agent, on secretory activities of canine tracheal secretory cells and on behaviour of glycoprotein in these secretory cells were investigated histologically and histochemically. Following bromhexine treatment, the number of total glycoprotein-containing goblet cells (GC) remained the same. The number of acid glycoprotein (AGP)-containing GC was reduced concentration-dependently, while neutral glycoprotein (NGP)-containing GC significantly increased with doses of 10-6, 10-5 and 10-4M. The number of sulphated glycoprotein (SGP) in AGP-containing GC decreased concentration-dependently. Acinar inner diameter of the submucosal gland and an acinar inner diameter of this gland to wall ratio (AIWR) increased with doses of 10-5 and 10-4M. Particularly, AIWR significantly increased with dose of 10-4M. Thickness of the acinus tended to slightly decrease concentration-dependently. AGP content in glandular cells decreased, while NGP content in these cells markedly increased, concentration-dependently. SGP content in the glandular cells decreased. Total saccharide and protein concentrations in the incubation fluid significantly increased with higher concentrations of the treatment, whereas N-acetylhexosamine slightly decreased concentration-dependently. These findings suggest that bromhexine does not enhance secretory activities of GC, but does stimulate the activities of the submucosal glands, when the drug is given in higher concentrations. Bromhexine markedly dissolves AGP in granules of the secretory cells.

Animals↗