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Biomedical subjects

K Takata

Publications and source records attributed to K Takata.

At least 199 records · Page 11Linked to original sources
PubMed1988

Monitoring of 131I in milk and rain water in Japan following the reactor accident at Chernobyl and estimates of human thyroidal dose equivalents.

Iodine-131 in milk and in rain water in Nagoya, Japan, (a location 8,000 km from Chernobyl) was monitored between May and July 1986. The 131I concentration in rain water ranged from 43.1 Bq L-1 on 4 May to 15 mBq L-1 on 12 July, and that in milk ranged from 21.8 Bq L-1 on 19 May to 11 mBq L-1 on 14 July. Iodine-131 concentrations in milk were estimated to be 4 to 6 times greater than those in rain water during the first few weeks after the accident. Both concentrations decreased with approximately the same effective half-life of 5.9 +/- 0.3 d for rain water and 5.0 +/- 0.2 d for milk. The 131I concentration in milk sold in markets varied from dairy to dairy and ranged from 0.07 to 0.2 times that in fresh milk. The maximum thyroidal dose equivalents estimated for an adult man and for a baby were far lower than the population annual dose equivalent to the thyroid from natural radiation.

Accidents↗
PubMed1988

Localization of high concentrations of phosphotyrosine-modified proteins in mouse megakaryocytes.

Phosphorylation of tyrosine residues of cellular proteins is a rare event and is considered to be related to the regulation of cellular growth, differentiation, and some forms of neoplastic transformation. Using high-affinity antibodies specific to phosphotyrosine (P-Tyr), we have shown the presence at high concentrations of P-Tyr-modified proteins in mouse bone-marrow megakaryocytes. Immunofluorescence microscopy of semithin frozen sections revealed that P-Tyr labeling was localized in a punctate pattern in the majority of the cytoplasm. The thin outer rim of the cytoplasm and the cell membrane was devoid of the label. Immunogold electron microscopy of ultrathin frozen sections showed that P-Tyr labeling was concentrated mostly on the membranes of the vesicles in the cytoplasm. The membrane demarcation system characteristic of megakaryocytes was not labeled. The intensity of P-Tyr labeling varied from one megakaryocyte to another. These results suggest that tyrosine phosphorylation of specific proteins might be correlated with the developmental stage of megakaryocytes, possibly related to the formation and deposition of the granules.

Animals↗
PubMed1988

[Prostatic tissue levels of cefpiramide (CPM)].

The concentration of CPM in prostatic tissue and serum in 12 patients with benign prostatic hypertrophy was measured. One gram of CPM was injected intravenously prior to prostatectomy. One, 2, 3 and 5 hours following the administration of CPM, the mean serum level of CPM was 142, 88.2, 87.4 and 61.2 micrograms/ml, respectively, while the mean level in the prostatic tissue was 48.3, 15.1, 15.6 and 8.3 micrograms/g, respectively. The prostatic tissue level of CPM was thought to be enough to eradicate gram-negative and gram-positive bacteria in the prostate. It is presumed from our study that clinical effectiveness of CPM might be expected in the case of acute or chronic bacterial prostatitis.

Cephalosporins↗
PubMed1988

Swelling of the cauda equina in patients who have herniation of a lumbar disc. A possible pathogenesis of sciatica.

Morphological changes in the cauda equina in patients who have herniation of a lumbar disc have not been previously reported, to our knowledge. Using computed tomographic myelography, we found swelling of nerve-root elements in the cauda equina that corresponded to the affected root in seventeen of twenty-eight patients who had proved herniation of a lumbar disc. All seventeen patients had severe sciatica. The swelling of the nerve-root elements gradually returned to normal after surgical decompression, which was also associated with improvement of the sciatica. Patients who did not have severe sciatica did not show swollen nerve-root elements. These findings may be an important clue to the mechanism of sciatic pain in patients who have herniation of a lumbar disc.

Adolescent↗
PubMed1988

Receptor-mediated internalization of high density lipoprotein by rat sinusoidal liver cells: identification of a nonlysosomal endocytic pathway by fluorescence-labeled ligand.

Rat sinusoidal liver cells possess the surface receptor for high density lipoprotein (HDL) (Murakami, M., S. Horiuchi, K. Takata, and Y. Morino. 1987. J. Biochem. (Tokyo) 101: 729-741). The present study was undertaken to determine whether cell surface-bound HDL underwent subsequent endocytic internalization by using 125I-labeled HDL and fluorescein isothiocyanate-labeled HDL (FITC-HDL). The cell-associated radioactivity obtained by a 40-min incubation with 125I-labeled HDL at 37 degrees C was released into the medium as acid-precipitable forms upon further incubation at 37 degrees C. When further incubated at 0 degree C instead of 37 degrees C, however, this release was significantly reduced. A similar phenomenon was observed after the cell-associated ligands had been treated with trypsin. The cell-associated ligands obtained after a 1-hr incubation with 125I-labeled HDL at 0 degree C were largely counted for by those bound to the outer surface of the cells, thus suggesting that HDL is internalized into cells at 37 degrees C but not at 0 degree C. Moreover, when cells were incubated with FITC-HDL at 0 degree C, the cell-associated ligands were found in a pH 7.2 +/- 0.1 compartment, whereas when incubated at 37 degrees C, its microenvironmental pH became much more acidic, exhibiting pH 6.2 +/- 0.1. Furthermore, this value returned to 7.1 +/- 0.1 upon treatment with carbonylcyanide m-chlorophenylhydrazone known to dissipate the total protonomotive force. These results suggest, therefore, that the internalization process does follow receptor-mediated binding of HDL in rat sinusoidal liver cells. This notion was also supported by fluorescence microscopic observations.

Animals↗
PubMed1988

Degenerative spondylolisthesis. Pathophysiology and results of anterior interbody fusion.

With special attention to the articular facets, an inspection of dry human spinal columns, microradiographic studies of cadaveric specimens, and animal experiments revealed that development of degenerative spondylolisthesis is attributable to rotational strain on the facetal joints at the level of involvement. Disc degeneration predisposes to intersegmental instability and rotational strain, which result in secondary osteoarthritic change of the articular processes and segmental canal stenosis. Thirty-six patients with degenerative spondylolisthesis were treated with anterior interbody fusion (AIF) for segmental canal stenosis at the authors' hospital during 1958-1985. The surgical results of these patients reveal that AIF corrects malalignment of the lumbar spine by complete discectomy, reduces the slip and restores the disc height, and resolves nerve compression, both from the front and from behind, by enlargement of the stenosing canal. In addition, AIF has consistent and satisfactory clinical results at long-term follow-up evaluation because it resolves intersegmental instability, an important problem of degenerative spondylolisthesis. AIF is a reasonable and reliable treatment for patients younger than 60 years of age with segmental stenosis.

Adult↗
PubMed1988

Fracture of the posterior margin of a lumbar vertebral body.

Using computed tomography, we studied twenty-nine patients who had thirty-one fractures of the posterior margin of a vertebra in the lumbar spine. Based on our findings, these fractures were classified morphologically into three types: a simple separation of the entire margin; an avulsion fracture of some of the substance of the vertebral body, including the margin; and a more localized fracture. In this series, twenty-two of the thirty-one fractures were associated with a defect involving the affected end-plate. This fact suggests that the pathogenesis of these fractures may be the fragility of the end-plate.

Adolescent↗
PubMed1987

Distinction in the mode of receptor-mediated endocytosis between high density lipoprotein and acetylated high density lipoprotein: evidence for high density lipoprotein receptor-mediated cholesterol transfer.

The interactions of high density lipoprotein (HDL) and acetylated high density lipoprotein (acetyl-HDL) with isolated rat sinusoidal liver cells have been investigated. Cellular binding of 125I-acetyl-HDL at 0 degrees C demonstrated the presence of a specific, saturable membrane-associated receptor. This receptor was affected neither by formaldehyde-treated albumin nor by low density lipoprotein modified either by acetylation or malondialdehyde, ligands known to undergo receptor-mediated endocytosis by the cells, indicating that the receptor for acetyl-HDL constitutes a distinct class among the scavenger receptors for chemically modified proteins. Parallel binding experiments using 125I-HDL also revealed the presence on these cells of a receptor for unmodified HDL. The ligand specificities of these two receptors were similar to each other except that the acetyl-HDL receptor was sensitive to polyanions such as dextran sulfate and fucoidin. Interaction of HDL with the cells at 37 degrees C was totally different from that of acetyl-HDL. Cellular binding of HDL was not accompanied by subsequent intracellular degradation of its apoprotein moiety, whereas its cholesterol moiety was significantly transferred to the cells. In contrast, acetyl-HDL was endocytosed and underwent lysosomal degradation as a holoparticle. This shift in receptor-recognition from the HDL receptor to the acetyl-HDL receptor was accomplished by acetylation of approximately 8% of the total lysine residues of HDL apoprotein. This unique difference in endocytic behavior between HDL and acetyl-HDL suggests a potential link of the HDL receptor to HDL-mediated cholesterol transfer in sinusoidal liver cells.

Acetylation↗
PubMed1987

[Data processing system of personnel exposure with personal computer].

This paper describes a software package that manages personnel exposure data with a personal computer. The exposure data is automatically transferred to the computer through a floppy disk supplied by film badge service companies. The computer processes data of about 4000 persons who belong to the 11 facilities and prints out the reports on the distribution of personal exposure level. This system made it possible for the radiation protection division to rapidly investigate the actual situation of occupational exposure with less laborious works.

Air Pollution, Radioactive↗
PubMed1987

[A rare case of adenocarcinoma of the bladder following ileocystoplasty].

This is a report of a case of well-differentiated adenocarcinoma found 14 years after ileocystoplasty. Total cystectomy and right ureterocutaneostomy were performed, and the origin of this tumor was proved to be the ileal part of ileocystoplasty. This is a rare case of adenocarcinoma in the ileal part of ileocystoplasty, because a review of the literature revealed only three other such cases.

Adenocarcinoma↗