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Biomedical subjects

K Kiyono

Publications and source records attributed to K Kiyono.

At least 37 records · Page 2Linked to original sources
PubMed1994

Ultrasonography of thymoma with pathologic correlation.

Preoperative ultrasonograms of 11 surgically proved thymomas and ex vivo ultrasonograms of 3 resected specimens were compared with pathologic findings of resected specimens. Among 11 thymomas 7 appeared solid, 3 were solid with several cystic regions, and the remaining one was unilocular cystic in appearance. Cystic regions on ultrasonograms corresponded to cystic changes on pathologic specimens. Six malignant thymomas showed a typical lacy appearance on ultrasonograms, which corresponded to the lobulated configuration separated by fibrous septa shown on the pathologic specimens.

Adult↗
PubMed1993

3-Cyano-2,6-dihydroxypyridine (CNDP), a new potent inhibitor of dihydrouracil dehydrogenase.

3-Cyano-2,6-dihydroxypyridine (CNDP) was identified as a potent inhibitor (IC50 value, 4.4 nM) of dihydrouracil dehydrogenase (DHUDase) [EC 1.3.1.2], a rate-limiting enzyme in 5-fluorouracil (5-FU) degradation. The inhibitory activity of CNDP was about 2,000 times that of uracil under our assay conditions. Kinetic analyses with partially purified enzyme from rat liver revealed that the mechanism of inhibition of DHUDase by CNDP was of mixed type with an inhibition constant (Ki) of 1.51 nM. CNDP had less effect on 5-FU phosphorylation than on 5-FU degradation. The inhibitory effect of CNDP on ribosylation of 5-FU was 600 to 1,000 times less than that on DHUDase. Moreover, CNDP did not inhibit uridine kinase, thymidine kinase, or pyrimidine phosphoribosyltransferase. Coadministration of CNDP with 1-ethoxymethyl-5-fluorouracil (EM-FU) to rats with Yoshida sarcoma elevated the level of 5-FU in both the blood and the tumor and enhanced the antitumor effect of EM-FU. These findings indicated that CNDP would be a useful chemical modulator in chemotherapy with 5-FU or its prodrugs.

Alanine↗
PubMed1992

[Radiation therapy of intracranial germinoma].

The appropriate radiation dose and field for the treatment of intracranial germinoma were investigated in 33 patients. Recurrences were observed in 4 cases treated with local field irradiation only, and all of them were recognized at the margin of the radiation field or under the dose (less than 25 Gy) area. This suggests that whole cranial irradiation (dose of 25 to 30 Gy) should be added even if the tumor is solitary. The effective dose for cerebrospinal dissemination appears to be 25-35 Gy, but prophylactic CNS irradiation seems unnecessary for patients who have not undergone surgical procedures. Changes in mental status were seen in 5 patients (26.3%). Doses of over 59 Gy may be related to this complication.

Adolescent↗
PubMed1992

Increase of S-(1,2-dicarboxyethyl)glutathione in regenerating rat liver.

Changes in the level of S-(1,2-dicarboxyethyl)glutathione (DCE-GS) with time were determined during regeneration of rat liver after partial hepatectomy. The DCE-GS level increased in regenerating rat liver, reaching a maximum level (4.7-fold) on day 2 and reverted to the normal level in 1 week. During the liver regeneration process, the activity of DCE-GS-synthesizing enzyme in the liver retained its control level, while the level of glutathione--a substrate of the enzyme in the liver--fluctuated in parallel with that of DCE-GS.

Animals↗
PubMed1992

MR imaging of thymoma: radiologic-pathologic correlation.

MR images in 17 patients with surgically proved thymomas (12 malignant and five benign) were reviewed and compared with pathologic specimens. In nine cases, MR images of excised specimens also were made and evaluated. On T2-weighted images, 11 of 12 malignant thymomas had an inhomogeneous signal intensity, half with and half without a lobulated internal architecture. None of the five benign thymomas had a lobulated internal architecture, and they all had a moderately or slightly inhomogeneous signal. Cystic regions and/or hemorrhage were noted pathologically, and corresponded to areas of inhomogeneous high signal intensity seen on T2-weighted images. Examination of the excised specimens in malignant thymomas showed that the lobulated configuration seen in the tumors was caused by thick fibrous septa. Our experience suggests that, although calcification cannot be identified, MR is helpful in making a differential diagnosis of mediastinal tumors and in determining malignancy of thymoma.

Adult↗
PubMed1992

Intrathoracic neurogenic tumors: MR-pathologic correlation.

An MR-pathologic correlation of nine intrathoracic neurogenic tumors (three neurofibromas, four schwannomas, and two ganglioneuromas) was performed to characterize their MR appearances. The three types of intrathoracic neurogenic tumor were found to have characteristic appearances on MR images that should be helpful when establishing the differential diagnosis of posterior mediastinal tumors. The MR and histologic features of these tumors are illustrated and described in this essay.

Adolescent↗
PubMed1990

High resolution ultrasound of the chest wall.

To study the detailed normal ultrasonic anatomy of the pleura and chest wall, high resolution (7.5 MHz) ultrasonograms were obtained from cadaver chest wall specimens and compared with thin section computed tomograms and anatomical specimens. Ultrasonograms show three layers of the intercostal muscles (internal, external and innermost), covered by the "echogenic pleural line." The "echogenic pleural line" is caused by composite echoes from the inner parietal pleura, and the outer endothoracic fascia, with the fatty tissue covering both sides of the fascia, which are located deep to the chest wall muscles. On ultrasonograms, the subpleural fat tissue, when abundant, appeared as an apron-like structure hanging down from the inner surface of the rib (subpleural fat pad), or diffuse fat accumulation mimicking the pleural thickening.

Humans↗
PubMed1989

[Effects of Er:YAG laser irradiation on human extracted teeth].

The ablation effects of the Erbium:YAG laser (wave length: 2.94 microns) on the human extracted teeth were examined histopathologically. The enamel surface of the human extracted tooth was irradiated by the laser at 500 mJ, 1 pps or 3 pps: 3, 15, 30, 50 and 100 shots. After observation under a dissecting microscope, the teeth were placed in a demineralizing solution of 0.1 M lactate buffer with 6% hydroxyethyl cellulose (pH 4.5) in order to evaluate the acid resistance of the enamel adjacent to the ablated area. After 4 days, the degree of demineralization of the surrounding enamel was assessed by contact microradiography. The result showed that every irradiated tooth had a clear-cut defect, and almost all the teeth had acquired acid resistance at the enamel surrounding the ablated portion. The other experiment was carried out to estimate the effects of the Er:YAG laser through a contact probe. The enamel, dentin and cementum of the extracted teeth were irradiated at 39 mJ or 74 mJ, 10 pps; 10 shots. The teeth were observed under a dissecting microscope. The result clearly indicated that the Er:YAG laser guided by the contact probe could also produce a defect in the dental hard tissue. The above-mentioned findings suggested that the Er:YAG laser could pave the way for the cavity preparation with acid-resistant cavity margin.

Dose-Response Relationship, Radiation↗
PubMed1988

Disruption of the CHO1 gene encoding phosphatidylserine synthase in Saccharomyces cerevisiae.

A Saccharomyces cerevisiae mutant that lacked phosphatidylserine synthase [EC 2.7.8.8] (CDP-1,2-diacyl-sn-glycerol: L-serine O-phosphatidyltransferase) completely was constructed by disrupting its structural gene, CHO1. Over two-thirds of its coding region, from the starting to the 200th codon, was replaced with a LEU2 DNA fragment. This new cho1 mutant showed no detectable synthesis of phosphatidylserine but grew slowly in a medium that contained either ethanolamine or choline. These results indicate that phosphatidylserine synthase and most probably phosphatidylserine are dispensable in S. cerevisiae but necessary for its optimal growth. Additional supplementation with myo-inositol raised the cellular content of phosphatidylinositol and improved the growth of the mutant, suggesting the importance of the negative charges of the membrane surface. The CHO1-disrupted mutant, when grown on choline, accumulated phosphatidylethanolamine to a significant level even after extensive dilution of the initial culture. It segregated prototrophic revertants that could synthesize phosphatidylethanolamine without recovery of phosphatidylserine synthesis. These results imply the presence of a route(s) for the formation of ethanolamine or its phosphorylated derivative in S. cerevisiae.

Blotting, Southern↗
PubMed1988

The number and size of normal mediastinal lymph nodes: a postmortem study.

For the CT diagnosis of pathologically enlarged nodes, information concerning the size of normal nodes is required. We studied 40 adult cadavers and determined the number and size of normal lymph nodes for each region of the mediastinum, counting all nodes and directly measuring the short and long diameters of each in the transverse plane of the node. The location of each node was classified according to the American Thoracic Society system, and the range and standard maximum sizes of normal lymph nodes in each location were determined. Nodes were found in 90-100% of cadavers in regions 4, 7, and 10; and in 68-85% of cadavers in regions 2 and 6. The average number of lymph nodes found was 3.5-4.8 in regions 4, 6, and 10R; 2.1-2.9 in regions 2, 7, and 10L; and 0.1-1.2 in all other regions. The mean short transverse diameters ranged from 2.4 to 5.6 mm, and the mean long transverse diameters ranged from 3.9 to 10.0 mm. The largest mean short and long transverse diameters were found in region 7, the next largest were in region 10R, followed by regions 4, 5, and 10L. We noted a different maximum normal size of lymph nodes in each region of the mediastinum. The short transverse diameter, which showed a smaller variation, appeared to be a more useful parameter than the long transverse diameter. We propose a standard for maximum normal short transverse diameters for nodes in each region of the mediastinum as follows: 12 mm for nodes in region 7; 10 mm for nodes in regions 4 and 10R; and 8 mm for nodes in other regions. The maximum long transverse diameters showed a wider variation, ranging from 25 to 10 mm.

Female↗
PubMed1988

Ultrasonic evaluation of cervical metastatic lymphadenopathy.

We investigated the location, size, and shape of cervical lymph nodes in head and neck cancer, using a 7.5-MHz ultrasound scanner. First, the different criteria for normal size were obtained for cervical lymph nodes in each region; lymph nodes greater than 9 mm in thickness in the internal jugular chain or greater than 7 mm in thickness in the submandibular and submental chains should be suspected of harboring metastatic foci. Second, metastatic nodes showed a more rounded configuration than nonmetastatic ones. Third, a comparative study of metastatic lymph nodes between the in vivo and in vitro ultrasonograms and the corresponding histopathological findings disclosed that an echogenic region in an ultrasonogram of a metastatic node was caused by coagulation necrosis, and a cystic area of liquefaction necrosis.

Carcinoma, Squamous Cell↗
PubMed1988

[Recurrence of non-Hodgkin's lymphoma: late recurrences].

563 patients with Stage I and II non-Hodgkin's lymphoma were treated by radiotherapy. 34 recurrences that occurred after 3 years from initial treatment were seen in those patients. 15 (44%) of 34 recurrences occurred after 5 years. 20 patients (59%) had remission by re-treatment, and 13 (38%) survived more than 2 years. 20 (59%) of recurrences were seen on head and neck lesions and superficial lymph nodes.

Adult↗
PubMed1987

Primary structure and product characterization of the Saccharomyces cerevisiae CHO1 gene that encodes phosphatidylserine synthase.

An open reading frame of 828 base pairs was found in the CHO1 gene region of Saccharomyces cerevisiae by nucleotide sequencing analysis. Its enhanced expression with the aid of the PHO5 regulatory sequence resulted in an overproduction of a protein with a molecular weight of approximately 30,000, which in turn was converted by proteolysis to active phosphatidylserine synthase, whose molecular weight was approximately 23,000. The larger protein was concluded to be the primary product of the CHO1 gene, since its amino-terminal sequence was identical to that deduced from the nucleotide sequence of the above open reading frame, except for the terminal methionine residue. A partial homology in primary structures was noticed between this yeast enzyme and phosphatidylglycerophosphate synthase of Escherichia coli which also uses CDP-diacylglycerol as a substrate. The overproduced phosphatidylserine synthase in both microsomal and extensively purified fractions displayed two different Km values for L-serine, i.e., 0.14 mM at low L-serine concentrations and 9.5 mM at high L-serine concentrations. This may indicate a negatively cooperative regulation of this enzyme activity or the presence of two active components with different affinities for L-serine.

Amino Acid Sequence↗
PubMed1987

[Radiotherapy of nasopharyngeal carcinoma].

The results of irradiation on fifty seven patients with nasopharyngeal carcinoma, treated from 1964 to 1985 at the Shinshu University Hospital, were studied. Forty-two percent of the patients had T3-4 primaries and 68% had N1-3 regional nodes; 86% had Stages III-IV of the disease. Of the 57 patients, 32 had squamous cell carcinomas, and 25 had lymphoepitheliomas. The overall 5-year survival rate was found to be 57%. Primary size (T) and histology influenced the survival of patients; the 5-year survival rate was 70% for T1-2 primary and 39% for T3-4 primary, and 39% for squamous cell carcinoma and 80% for lymphoepithelioma.

Adolescent↗
PubMed1986

Overproduction of proteins encoded by lambda replicon-integrated plasmid: effect of partial inactivation of cI repressor.

Composite plasmids containing the 7.2-kb fragment of bacteriophage lambda cI857cro27, essential for lambda DNA replication and its control, have been constructed. The plasmids contained, in addition, pBR322, a part of Co1E1, and the Escherichia coli pss gene, coding for phosphatidylserine synthase. When the plasmid-harboring cells were induced at different temperatures, the phosphatidylserine synthase production was maximum at 37 degrees C, and the specific activities at 37 degrees C continuously increased until the culture reached saturation. The results suggest that, when the cro gene is defective, only a transient temperature for inactivation of cI repressor provides both the increase in copy number of the plasmids and cellular activities that allow overproduction of the plasmid-encoded protein.

Bacteriophage lambda↗