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Biomedical subjects

H Mishima

Publications and source records attributed to H Mishima.

195 records · Page 11Linked to original sources
PubMed1975

Freeze-etching images of rabbit thyroid glands.

Freeze-etching images of the rabbit thyroid were described. The outline of the structure of the follicular epithelial cell in freeze-etching techniques is consistent with that in ultrathin sections. The subapical junctional complex consists of tight and gap junctions. According to the number of strands (5-16) indicating the tight junction and the depth of the tight junction (0.3-1.1 mum), this is classified into the "very tight" form of CLAUDE and GOODENOUGH(1973). The number of intramembranous particles per mum2 on the A-face of the lateral as well as the apical plasma membrane is far larger than that on the B-face. The limiting membrane of the reabsorbed colloid droplet shows also a similar pattern to that of the plasma membrane. The capillary endothelial cells show numerous fenestations whose population density is about 20/mum2 on the endothelial surface except in the parajunctional zone.

Animals↗
PubMedDate not supplied

In vivo F-19 chemical shift imaging with FTPA and antibody-coupled FMIQ.

A mixture of perfluoromethyldecahydroisoquinoline (FMIQ) emulsion coupled with anti-CEA (carcinoembryonic antigen) antibody and perfluorotripropylamine (FTPA) was injected into a nude mouse inoculated with human colon carcinoma LS174T. Three days after the injection, in vivo fluorine-19 chemical shift images of the spectral signals of the two perfluorocarbons (PFCs) were obtained simultaneously. The signal intensities and distributions of FMIQ and FTPA were similar in the liver and spleen but different in the tumor. FMIQ was detected in almost the entire tumor, with scattered areas of high uptake. FTPA, however, was detected only in the center of the tumor. The results suggest that F-19 chemical shift imaging of two PFCs, one coupled to antibody and the other not, has potential application in tumor diagnosis.

Animals↗
PubMedDate not supplied

High resolution MR imaging of the bilateral hips with dual phased-array coil.

We applied dual-flex coils in a phased-array configuration to obtain high resolution MR images of the bilateral hips and compared the image quality with non-phased-array imaging. Multiple fast spin-echo images of both hips were obtained in a single acquisition. Two consecutive acquisitions with and without phased-array capability were performed in 22 hips and a fluid-filled phantom. The signal-to-noise ratio (S/N) enhancement values were calculated. Subjective image analysis was also obtained from three independent reviewers. High quality MR images were obtained using dual-array coils with a S/N enhancement value of 1.40 for a phantom and 1.83 to 2.22 for subject hips. On subjective analysis, the dual array enhanced delineation of the acetabular labrum, articular cartilage, and retained fluid. The dual array may be of diagnostic value with a higher S/N enhancement and subjective superiority of the images obtained.

Acetabulum↗
PubMedDate not supplied

Detection of interleukin-1 beta in the tear fluid of patients with corneal disease with or without conjunctival involvement.

To investigate the role of Interleukin-1 (IL-1) in the pathobiology of the cornea, we measured IL-1 beta concentration in tear fluid samples from patients with corneal disease. Twenty patients with unilateral corneal disease were included in the study. Tear fluid samples were collected during the active stages of the disease and following resolution. The fellow (unaffected) eyes served as controls. The concentration of IL-1 beta in the tear fluid samples was measured using a sandwich ELISA method. IL-1 beta was detected in tear fluid from five eyes (three eyes with chemical burns, one with a Pseudomonas aeruginosa corneal ulcer, and one with a peripheral corneal ulcer) at concentrations between 29 and 218 pg/mL. IL-1 beta was not detected in tear fluid from the remaining 15 affected eyes, nor from the control eyes. The detection of IL-1 beta in tear fluid correlated with limbal conjunctival involvement, but did not correlate with the type of disease, size of epithelial defect, or degree of stromal involvement. IL-1 beta in the tear fluid may be one of the factors modifying the complex inflammatory process of the anterior ocular surface.

Adolescent↗
PubMedDate not supplied

Differences in the expression of glucose transporter protein isoforms in human retinoblastoma cell lines.

We investigated the expression of glucose transporter (GLUT) protein isoforms in two human retinoblastoma cell lines, Y79 and WERI-Rb1, by Western blotting analysis with anti-GLUT1, 2, 3, and 4 antibodies. GLUT1 and GLUT4 proteins were detected in Y79, whereas GLUT1 and GLUT3 proteins were found in WERI-Rb1. GLUT2 protein was not detected in Y79 or WERI-Rb1. Our findings are of interest because (1) the expression of GLUT protein isoforms in the two retinoblastoma cell lines was different, and (2) GLUT4 protein, the insulin-sensitive GLUT isoform, was detected in Y79. This suggests that these cell lines have different mechanisms of glucose transport.

Animals↗
PubMedDate not supplied

Collagenolytic activity of keratocytes cultured in a collagen matrix.

To study the mechanism of collagen degradation by keratocytes, we developed the new in vitro model in which keratocytes were cultured three-dimensionally in a collagen matrix. Subcultured rabbit keratocytes were embedded in a type I collagen matrix and cultured in serum-free medium. Collagenolytic activity of the cells was determined by measuring the amount of hydroxyproline released into the medium from degraded collagen. Activities of collagenase in the medium were also measured, using collagen labeled with fluorescein isothiocyanate as a substrate. The presence of plasminogen was required for collagen degradation by keratocytes. In the presence of plasminogen, the amount of collagen degradation depended on both the cultivation period and the number of cells. The addition of interleukin-1 (IL-1) stimulated the collagen degradation in a dose-dependent manner. This stimulatory effect of IL-1 was completely inhibited by the addition of IL-1 receptor antagonist (IL-1ra). Collagenase activity in the medium was stimulated by the addition of IL-1, and IL-1ra antagonized this stimulatory effect. These findings indicate that our present model may be useful for investigating the mechanism of collagen degradation by keratocytes.

Animals↗
PubMedDate not supplied

The effect of corneal epithelial cells on the collagen gel contraction by keratocytes.

To understand the mechanism of the contraction of cicatricial tissues after corneal stromal wounding, we investigated the effect of corneal epithelial cells on the collagen gel contraction by keratocytes. Subcultured rabbit keratocytes were embedded in type I collagen gel and cultured. Rabbit corneal epithelial cells were cultured separately and the culture medium was collected and used as an epithelial cell-conditioned medium (ECCM). The collagen gel contraction by keratocytes was determined by measuring the diameters of the collagen disks once a day for 5 days. In the presence of fetal calf serum, the diameter of the collagen gel decreased in linear proportion to the number of keratocytes, but in inverse proportion to the concentration of collagen. The addition of the ECCM enhanced the collagen gel contraction by keratocytes in a dose-dependent manner. This stimulatory activity was found in the ECCM obtained from 3- to 7-day cultures of epithelial cells. These findings suggest that corneal epithelial cells secrete factor(s) that stimulate the collagen gel contraction by keratocytes.

Animals↗
PubMedDate not supplied

19F-MRI of stomach and intestine using 50% FTPA emulsion under 2 T MRI system.

1H-MRI is of clinical value in many lesions, but imaging of gastrointestinal lesions is still difficult by 1H-MRI. To overcome this weak point of 1H-MRI, rabbit stomachs were examined by 19F-MRI using 50% FTPA emulsion. We also examined the stability of 50% FTPA emulsion in the stomach and its absorption from the gastrointestinal tract. We found that 50% FTPA emulsion was very stable at pH 1.5, and only a very small amount was absorbed. A rabbit (weighing 2 kg) was anesthetized, and 100 ml of 50% FTPA emulsion was infused into the stomach by catheter. 19F-MRI was performed in this rabbit using a 2 T superconducting MRI system designed for human use, and clear pictures of the stomach were obtained. From our results we conclude that 19F-MRI of the stomach using 50% FTPA emulsion is of practical value.

Animals↗
PubMedDate not supplied

Treatment of sick sinus syndrome with permanent cardiac pacemaker. (Sick sinus syndrome and artificial pacemaker).

Twenty nine patients with sick sinus syndrome were treated from November, 1972 through July, 1976. Six cases had sinus bradycardia, 14 cases had sinoatrial block/sinus arrest and 9 cases had bradycardia-tachycardia syndrome. Twenty five patients received the implantation pacemaker with good result. There was found that an adequate pacing of the heart was effective for the control of the attack of tachyarrhythmia in the case with bradycardia-tachycardia syndrome.

Adolescent↗