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Biomedical subjects

T Kohno

Publications and source records attributed to T Kohno.

At least 451 records · Page 25Linked to original sources
PubMed1976

New approach to brain tumour chemoradiotherapy with cellular synchronization by colcemid.

Cellular synchronization using Colcemid as pretreatment for combined chemoradiotherapy was investigated. C6 rat brain tumour was cultured in RPMI medium containing 10(-5)-10(-7) Mol. of Colcemid for 24 hours. The basic cell kinetics were analysed with a Pulse Cytophotometer, which facilitated the analysis of tumour cell cycle phase distribution according to the DNA content. The effect of Colcemid depended on the concentration, and the minimal concentration showing continuous blocking during 48 hours after removal of the drug was 10(-6) Mol. G1 fraction of 2 C DNA content was reduced from 74% to 36%. G2-M phase of 4 C DNA content increased from 9% to 28%. S phase cells increased from 17% to 31%. Polyploid cells in the Tetraploid cell cycle could be recognized. The remaining 36% of cells within the GO + G1 peak of 2 C DNA content were considered to be diploid GO cells.

Brain Neoplasms↗
PubMed1972

Externally suppressible proline quadruplet ccc U.

Three (+1) frameshift mutations located at different genetic sites respond with high specificity to the same external suppressor. In each case, the suppressor restores small amounts of protein that is normal in electrophoretic mobility and heat stability. One of these proteins has been shown to have the wildtype amino acid sequence. The messenger RNA quadruplet CCCUappears to be common to all three frameshift sites and to be translated by the suppressor as proline. A likely suppressor agent is a proline transfer RNA with a quadruplet anticodon or its functional equivalent.

Alcohol Oxidoreductases↗
PubMedDate not supplied

Indocyanine green angiograms of choroidal nevi. comparison between confocal and nonconfocal scanning laser ophthalmoscope and fundus video camera.

PURPOSE: A fundus video camera and a nonconfocal scanning laser ophthalmoscope (SLO) detect direct light and indirect light, whereas a confocal SLO detects mostly direct light. Differences in confocal and nonconfocal SLO images and fundus video camera images are most likely due to their different optical systems. These differences were examined in indocyanine green (ICG) angiograms of a choroidal nevus. METHODS: A confocal SLO, a nonconfocal SLO, and a high resolution digital fundus video camera were used to obtain ICG angiograms of pigmented choroidal nevi in 4 patients for 30 minutes following dye injection. RESULTS: All the angiograms showed a hypofluorescent region in the nevus until 10-14 minutes after dye injection, except in 1 patient in whom no hypofluorescent region was seen in an early confocal-SLO angiogram. From 20 minutes to 30 minutes postinjection, the hypofluorescent regions were still visible in all fundus video camera angiograms and nonconfocal SLO angiograms but not in confocal SLO angiograms. CONCLUSIONS: Early angiograms taken with the three angiography systems showed a similar appearance of the choroidal nevus. However, late ICG angiograms with a confocal SLO showed different images from those taken with a nonconfocal SLO or a fundus video camera. It is suggested that the angiography system and the aperture size of an SLO should be selected according to the aspect of the pigmented choroidal nevus that is of interest in late-phase ICG angiography.

Adult↗
PubMedDate not supplied

Rapid injection of indocyanine green dye for evaluation of choroidal venous circulation.

PURPOSE: The purpose of this study was to investigate the effects of rapid intravenous administration of a small bolus of indocyanine green (ICG) dye on early phase findings of ICG angiography. METHODS: Rabbit eyes were used. Ten normal eyes, 5 eyes with occlusion of vortex veins, and 5 eyes with chorioretinal atrophy were examined by ICG angiography, and early-phase findings after a rapid injection of a small bolus of dye were compared with those obtained with an ordinary injection. RESULTS: In normal eyes, after the rapid injection it was possible to visualize some small bright fluorescent boluses in the choroidal veins from 6 to 12 seconds after injection, while with the ordinary injection they were unclear. In eyes with occlusion of vortex veins, the rapid injection resulted in visualization of the choroidal veins with delayed filling against the background, and the region of the choroidal veins with delayed filling could easily be determined. In eyes with chorioretinal atrophy, only the rapid injection clearly revealed the choroidal veins with delayed filling. CONCLUSIONS: The rapid injection made it possible to detect the choroidal veins with delayed filling that were not clearly and easily visible using an ordinary injection. Rapid injection of ICG dye is useful for a detailed examination of choroidal circulation.

Animals↗
PubMedDate not supplied

Mutation and expression of the DCC gene in human lung cancer.

Chromosome 18q is frequently deleted in lung cancers, and a common region of 18q deletions was mapped to chromosome 18q21. Since the DCC candidate tumor suppressor gene has been mapped in this region, mutation and expression of the DCC gene were examined in 46 lung cancer cell lines, consisting of 14 small cell lung carcinomas (SCLCs) and 32 non-small cell lung carcinomas (NSCLCs), to elucidate the pathogenetic significance of DCC alterations in human lung carcinogenesis. A heterozygous missense mutation was detected in a NSCLC cell line, Ma26, while homozygous deletion was not detected in any of the cell lines. The DCC gene was expressed in 11 (24%) of the 46 cell lines, and the incidence of DCC expression was significantly higher in SCLCs (7/14, 50%) than in NSCLCs (4/32, 13%) (P = .01, Fisher's exact test). Therefore, genetic alterations of DCC are infrequent; however, the levels of DCC expression vary among lung cancer cells, in particular, between SCLCs and NSCLCs. The present result does not implicate DCC as a specific mutational target of 18q deletions in human lung cancer; however, it suggests that DCC is a potential target of inactivation by genetic defects including intron or promoter mutations and/or epigenetic alterations. The present result also suggests that DCC expression is associated with some properties of SCLCs, such as a neuroendocrine (NE) feature.

Amino Acid Substitution↗
PubMedDate not supplied

High-grade endometrial stromal sarcoma after treatment with tamoxifen in a patient treated for breast cancer.

Tamoxifen has been widely used in breast cancer treatment. In recent years, the occurrence of uterine malignancies in patients receiving long-term tamoxifen therapy has attracted attention. Most of these malignancies are endometrial adenocarcinomas, but low-grade endometrial stromal sarcomas have occasionally been reported. Here we report a woman who developed a high-grade endometrial stromal sarcoma after receiving postmastectomy tamoxifen therapy. The patient underwent a left mastectomy at age 45 and subsequently received oral tamoxifen for 3 years. At age 51, she was diagnosed with endometrial stromal sarcoma, for which a radical hysterectomy was performed. High-grade endometrial stromal sarcoma was diagnosed by postoperative histologic examination. Immunostaining for the estrogen receptor was negative in sarcoma cells, but positive in the residual endometrial epithelium and the nucleus of adjacent stromal cells within the tumor. The patient has now survived disease-free for 37 months after surgery.

Administration, Oral↗
PubMedDate not supplied

Photocatalytic activity of TiO2 particulate films prepared by depositing TiO2 particles with various sizes.

TiO2 particles of various sizes were prepared by grinding in cyclohexanone, and TiO2 particulate films were obtained by depositing these TiO2 particles with various sizes onto a glass or quartz substrate. The effect of the particle size and thickness on the photocatalytic properties of the films was evaluated via oxidative degradation of gaseous 2-propanol. The initial rate of 2-propanol degradation under UV light irradiation for the films deposited with 30 nm TiO2 particles increased with increasing film thickness up to 600 nm, and reached a saturated value above this film thickness. Photocatalytic activity for the films with thickness below 600nm was larger when smaller TiO2 particles were deposited onto the substrate, due to the increase in the surface area of the particulate films. Furthermore, saturated values of the photocatalytic activity for thick films were smaller for the films deposited with smaller particles, which is mainly attributed to the change in crystal form of the particles during the grinding treatment.

2-Propanol↗
PubMedDate not supplied

Intrachoroidal dye leakage in indocyanine green fundus angiography after experimental commotio retinae.

Dye leakage in sodium fluorescein (FLUO) fundus angiography indicates damage to the blood-retinal barrier. However, dye leakage in indocyanine green (ICG) fundus angiography does not mean the same, because of the larger molecular size of the dye and impermeability of the choroidal vessels to it. The possibility of dye leakage in ICG angiography has not yet been revealed in an experimental study in which the blood-retinal barrier is undamaged. We report here that intrachoroidal dye leakage may occur in ICG angiography in an experimental model of the traumatic retinal opacity of the rabbit eye, even when the blood-retinal barrier is undamaged. This mechanism of dye leakage in ICG angiography is quite different from the leakage of FLUO angiography. Pathological choroidal vessels with increased permeability, such as choroidal neovascularization under the retinal pigment epithelium, can be observed using ICG angiography.

Animals↗
PubMedDate not supplied

Computer assisted image analysis using the subtraction method in indocyanine green angiography.

The choroidal vessels are three dimensionally distributed and very complex in their patterns. They often appear to be overlaid in indocyanine green (ICG) angiograms so it is harder to analyze ICG angiography than fluorescein angiography. When an earlier frame is subtracted from a later frame in a sequence of angiograms, the fluorescence which has increased during the time between the two frames can theoretically be demonstrated. We applied computer-assisted image subtraction methods in selected clinical cases of directly acquired digital ICG angiography to demonstrate how this method works. We used software already installed in an IMAGEnet computer system (Topcon) for image subtraction. We applied the subtraction technique in 18 cases with various diseases. When two images with a time difference of several seconds were subtracted, filling of the choriocapillaris, the neovascularization or the pathological vessels could be observed. When the images had a time difference of several minutes, intrachoroidal dye leakage could be seen more clearly. This method is very helpful for analyzing pathological changes in ICG angiography in clinical cases, when two images are selected appropriately.

Adult↗
PubMedDate not supplied

Incising the thick retrolental fibrovascular tissue with a hooked sclerotome in persistent hyperplastic primary vitreous.

A technique for incising thick retrolental fibrovascular tissue and extensive cyclitic membrane is reported in a case of anterior persistent hyperplastic primary vitreous. A membranectomy was performed in a 1-month-old post-lensectomy baby via a limbal approach. A sclerotome tip was hooked to cut through an extremely thick fibrovascular tissue by rotating the sclerotome by its grip. Sutherland microscissors (Grieshaber, Switzerland) and a vitrectomy cutter were used for further membranectomy. The baby was followed-up until age 18 months. A total of 3 membranectomy sessions were required because of rapid cyclitic membrane formation, severe centripetal retraction of the membrane on the ciliary processes, and posterior synechia. Thorough membranectomy and cutting the iris edge maintained a clear pupillary area during the 13-month postoperative period. Extremely thick retrolental fibrovascular tissue is a challenging condition that can be dealt with by delicate instrumentation.

Anterior Eye Segment↗