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Biomedical subjects

E Miyahara

Publications and source records attributed to E Miyahara.

At least 19 recordsLinked to original sources
PubMed1998

Telomerase activity and alterations in telomere length in human brain tumors.

Telomerase activity was examined in 170 human brain tumor tissues, and terminal restriction fragment (TRF) length was examined in 152 of the 170. Telomerase activity was detected in 61.7% (66 of 107) of the neuroepithelial tumors. However, the detection rates of telomerase activity were widely different for different histopathological entities. In the case of astrocytic tumors, the detection rate was 20.0% (3 of 15) for grade II astrocytomas, 40.0% (6 of 15) for anaplastic astrocytomas, and 72.3% (34 of 47) for glioblastomas. The mean TRF length of the tumors with telomerase activity was significantly shorter than that of the tumors with undetectable telomerase activity for each tumor entity. In grade II and anaplastic astrocytomas, telomerase activity was an indicator of early histological progression and reduced survival of the patients, although there was no difference in MIB-1 staining indices between the tumors with and without telomerase activity at onset. In three astrocytic tumors, concurrence of telomere shortening and telomerase reactivation was observed at recurrence; in these cases, tumors progressed to a higher grade. Ten glioblastomas that progressed from lower-grade tumors exhibited telomerase activity, and their TRF lengths were reduced in 80% (8 of 10). In contrast, telomerase activity was detected in only 63.3% (19 of 30; P < 0.05) and the TRF length remained compatible with normal values in 56.7% (17 of 30; P < 0.01) of de novo glioblastomas. Thus, telomerase activity strongly correlated with potential tumor progression in the short term as well as with progression itself of the astrocytic tumors, whereas telomeres may still have been in the process of shortening in some of the de novo glioblastomas. High telomerase activity was exhibited in all primitive neuroectodermal tumors, anaplastic oligoastrocytomas, neuroblastomas, and oligodendrogliomas. TRF length was reduced in the majority (14 of 15) of three previously high-grade tumors, whereas it was compatible with that of normal brain tissues in the oligodendrogliomas, suggesting that telomerase activity with shortened telomeres correlates with the aggressive growth of high-grade neuroepithelial tumors. Tumor cell lines could be established from 17.2% (5 of 29) of neuroepithelial tumors with telomerase activity but not from tumors without this activity (P < 0.05), suggesting that telomerase reactivation is an essential event in the neuroepithelial cell immortalization in vitro. In nonneuroepithelial tumors, telomerase activity was detected in malignant tumors, such as germ cell tumors, lymphomas, metastatic adenocarcinomas, hemangiopericytomas, and an anaplastic meningioma. In contrast, such activity was not detected in benign tumors, including meningiomas, pituitary adenomas, hemangioblastomas and schwannomas, except for one hemangioblastoma that recurred four times and displayed malignant features at the fourth recurrence. These findings suggest that telomerase activity can be an index of malignant potential or malignancy itself in nonneuroepithelial brain tumors.

Adolescent↗
PubMed1998

Color vision in two observers with highly biased LWS/MWS cone ratios.

Two sisters, heterozygous carriers for congenital X-linked protanopia, were diagnosed as normal trichromats by the Rayleigh match on the anomaloscope. The heterozygous state was established by molecular analysis of their visual pigment genes. The normal color match establishes that the spectral sensitivities of their long-wavelength-sensitive (LWS) and middle-wavelength-sensitive (MWS) cone visual photopigments are within normal variability. Their FM 100-hue test error scores were low, demonstrating superior chromatic discrimination. Heterochromatic flicker photometric (HEP) spectral sensitivities were like those of protanopes. The estimated LWS/MWS cone ratios from the HFP data were 0.09/1 and 0.03/1, compared with ratios in the range of 0.6/1 to 10/1 for typical normal trichromats. Measurements of chromatic grating acuity on chromatically selective backgrounds were performed to study the cone mosaic. The data were consistent with a sparsity of LWS cones. Both protan carriers showed normal spectral sensitivities for all three cone types under cone isolating chromatic adaptation and normal three-peaked curves for increment thresholds on a white pedestal. Hue estimation, run on one carrier was normal. The equilibrium yellow locus was measured in the other carrier and was in the range of normal trichromats. The data indicate that normal color vision can occur even when the LWS/MWS cone ratio is quite abnormal.

Adaptation, Ocular↗
PubMed1998

[Usefulness of percutaneous low output microwave tissue coagulation therapy for solitary liver cancer].

The possible use of percutaneous transhepatic low output microwave tissue coagulation therapy (PMCT) using ultra-sonography under local anesthesia for solitary liver cancer was studied. The subjects were 13 patients having primary or metastatic liver cancer with solitary liver tumor less than 3 cm in diameter, including 7 hepatocellular carcinomas and 6 metastatic liver cancers. PMCT was performed continuously 3 times at an output of 30 watts for 30 seconds at a time. Tumors less than 3 cm in diameter were completely coagulated by irradiation from 2 to 6 times, judging by enhanced CT. No tumor recurrence was recognized in the coagulation area. However, in two cases of metastasis from pancreatic carcinoma, multiple metastases were found at another site in the liver by 2 months after PMCT. Thus, the results suggest that PMCT is a useful therapy for small liver tumor as a local control.

Aged↗
PubMed1997

Isolated dural metastasis from colon cancer.

We report a case of isolated dural metastasis from colon cancer. Neuroradiologic and intraoperative findings indicated that the tumor was extra-axial, and histopathologic examination resulted in the correct diagnosis. Notable neuroradiologic findings of the present dural-based tumor were: diploic fat MRI signal disappeared in the tumor associated calvaria where bony change was absent on bone-window CT; abnormal subgaleal and epidural tissues were seen on MRI, both of which contained clusters of adenocarcinoma cells histopathologically. These findings suggest an infiltrative, malignant character, and help to differentiate between benign and malignant dural-based tumors.

Adenocarcinoma↗
PubMed1997

Color from motion: separate contributions of chromaticity and luminance.

'Color from motion' describes the perception of a spread of subjective color over achromatic regions seen as moving. The effect is produced with a stimulus display consisting of colored dots, randomly placed upon a white field, with dots in the test region differing in both chromaticity and luminance from those in the surround. Evidence is presented suggesting that color from motion may be regulated by mechanisms different from those for contour formation and color contrast. (1) Results based on ratings show that, in the absence of luminance differences between the dots in the test and those in the surround regions, chromaticity differences alone are sufficient to produce color spread from motion. As the equiluminance point is approached, subjective color spread is seen despite a reduction in the strength of the subjective contour. Thus, contour formation is not likely to be a prerequisite for color from motion. (2) Color matches show that the hue and saturation of the subjective color spread are determined largely by the chromaticity and the luminance of the dots in the test region, not by those of the dots in the surround for the values explored. This suggests that color from motion may arise in sites distinct from those responsible for the regulation of color contrast.

Color↗
PubMed1997

Contrast adaptation and the spatial structure of natural images.

Natural images have a characteristic spatial structure, with amplitude spectra that decrease with frequency roughly as 1/f. We have examined how contrast (pattern-selective) adaptation to this structure influences the spatial sensitivity of the visual system. Contrast thresholds and suprathreshold contrast and frequency matches were measured after adaptation to random samples from an ensemble of images of outdoor scenes or of synthetic images formed by filtering the amplitude spectra of noise over a range of spectral slopes. Adaptation selectively reduced sensitivity at low-to-medium frequencies, biasing contrast sensitivity toward higher frequencies. The pattern of aftereffects was similar for different natural image ensembles but varied with large changes in the slope of the noise spectra. Our results suggest that adaptation to the spatial structure in natural scenes may exert strong and selective influences on perception that are important in characterizing the normal operating states of the visual system.

Adaptation, Physiological↗
PubMed1997

[Usefulness of percutaneous microwave tissue coagulation therapy for solitary liver cancer].

The possible use of percutaneous transhepatic microwave tissue coagulation therapy (PMCT) using ultra-sonography under local anesthesia for solitary liver cancer was studied. The subjects were 8 patients having primary or metastatic liver cancer with solitary liver tumor less than 4 cm in size, consisting of 2 hepatocellular carcinomas, and 6 metastatic carcinomas. PMCT was performed continuously 3 times at the output of 30 watts for 30 seconds at a time. Tumors less than 3 cm in size were completely coagulated by irradiation from 2 to 5 times judged by enhanced CT. No recurrence of tumor was recognized in the coagulation area. But in some cases, multiple metastases were found at another site in the liver by 3 months after PMCT. Thus, the results suggest that PMCT is a useful therapy for small liver tumor as a local control.

Aged↗
PubMed1997

[A case of advanced hepatocellular carcinoma with portal invasion effectively treated by continuous intra-arterial chemotherapy with 5-fluorouracil].

A 79-year-old male diagnosed as advanced hepatocellular carcinoma with portal invasion was treated by continuous intra-arterial chemotherapy of 5-FU, which was continuously administered for 72 hours at a dose of 333 mg/mm/day every 2 weeks and repeated 12 times. Total dose of 5-FU was 14.4 g. Toxicity of this therapy was not recognized. Levels of AFP were reduced from 4385.6 ng/ml to 11.9 for 6 months. No tumor was recognized on CT scan at 6 months after starting this therapy, after 15 months of this therapy, the patient is alive and disease-free. Given the above results, continuous intra-arterial administration of this 5-FU therapy may be effective for patients with hepatocellular carcinoma.

Aged↗
PubMed1996

Increment threshold and purity discrimination spectral sensitivities of X-chromosome-linked color-defective observers.

The goal of the study was to evaluate spectral opponency in nine X-chromosome-linked color-defective observers. The tasks included increment threshold spectral sensitivity on an achromatic background, heterochromatic flicker photometry, and colorimetric purity discrimination. With a task of heterochromatic flicker photometry, the anomalous trichromatic observers showed spectral sensitivity of the corresponding dichromat. The increment threshold spectral sensitivity and colorimetric purity discrimination data were analyzed using the concept of standard cone photopigment spectral sensitivities for normal and defective vision, and a model that postulates one cone-additive and two cone-antagonistic systems. The model incorporated a shift of the peak spectral sensitivity of the long-wavelength-sensitive (LWS) pigment (for protan observers) or of the middle-wavelength-sensitive (MWS) pigment (for deutan observers). Two dichromats and two anomalous trichromats did not show clear evidence of LWS vs MWS cone antagonism. Five anomalous trichromats showed such cone antagonism. Molecular genetic analysis of the opsin genes is presented for eight of the observers.

Color Vision Defects↗
PubMed1996

[Usefulness of subcutaneous implantable port with new one-way valve].

Because of the development of the subcutaneous implantable port, intra-arterial infusion chemotherapy for malignant tumor has been performed in safety and it is now possible to choose a more effective method of drug administration. Many problems remain, however. In this study, we investigated the performance of subcutaneous implantable port with a new one-way valve with safety, septum intensity and a back stream of blood. This new port was very safe, with good septum intensity and water backflow. In the performance test with a back stream of water into the catheter, water did not back up into the catheter connecting with the port with the one-way valve, but did so without the one-way valve after releasing a load of 2,000 g from the septum. This suggests that the catheter obstruction is decreased by adding a one-way valve to the port.

Catheterization↗
PubMed1996

Profile of T-cell receptor V beta gene usage of cytotoxic T cells induced by intrapleural administration of a streptococcal preparation, OK432, in malignant effusions.

T-cell receptor (TCR) gene rearrangements were analyzed in tumor-infiltrating lymphocytes (TIL) using the reverse transcription-polymerase chain reaction (RT-PCR) to determine whether oligoclonal expression of TCRV beta occurs in TIL, and if so, whether it is involved in the clinical response and mechanisms of locoregional immunotherapy using a streptococcal preparation, OK432. Patients with malignant effusion of various origins were treated with intrapleural administration of OK432, and clinical responses were assessed by cytological and chest X-ray examinations. Pleural exudate cells (PEC), obtained before and after the administration of OK432 (designated as pre- and OK432-PEC, respectively), were subjected to TCR analysis. Both pre-PEC and OK432-PEC showed highly diverse expressions of TCRV beta gene usage in either type of PEC. The frequency of TCRV beta 20 gene expression in OK432-PEC was significantly higher than in pre-PEC. Moreover, the over-expression of the TCRV beta 20 gene usage was also induced in the peripheral blood lymphocytes and pre-PEC of patients by in vitro OK432 stimulation, but not in the PBL of one healthy volunteer. Single-strand conformational polymorphism (SSCP) analysis revealed the clonotypes of these TCRV beta 20 genes. Autologous tumor-specific killing activity could be detected in OK432-PEC and was significantly reduced by treatment with a TCRV beta 20-specific monoclonal antibody. These findings suggest that the rearrangement of TCRV beta 20 gene usage may be involved in the autologous tumor-specific action of malignant effusions in the treatment with OK432.

Aged↗
PubMed1995

[T cell receptor V beta repertoire of locoregional lymphocytes in malignant effusions].

We analyzed the T cell receptor (TCR) V beta repertoire of lymphocytes obtained from patients with malignant effusion treated by locoregional immunotherapy. Polymerase chain reaction using a panel of V beta subfamily specific oligonucleotide primers(V beta 1-20) was employed after reverse transcription of mRNA isolated from the locoregional cells. No major oligoclonality of TCR repertoire was observed in effusion lymphocytes before the treatment. The expression level of V beta 13.1 repertoire was significantly higher in effusion lymphocytes than in peripheral blood lymphocytes before treatment. V beta 20 gene expression increased significantly after locoregional administration of OK-432. It is suggested that TCR V beta 13.1 may be responsible for effusion lymphocytes and TCR V beta 20 for OK-432-related antigenic stimulus.

Adult↗
PubMed1994

[Skin reaction to OK-432 and its dosage for locoregional administration].

Establishment of optimal dosage of OK-432, a streptococcal preparation, was studied based on its skin test was studied. Locoregional immunotherapy using OK-432 was conducted for patients with malignant fluids. More OK-432 was administered to patients having a weaker skin reaction to OK-432 and less to those having a stronger one, corresponding to their redness diameter of skin reaction. There was a marked difference in OK-432-skin test among patients. Some patients with malignant fluids having small redness responded to the treatment after a large amount of OK-432, and others were well controlled by a smaller dosage of OK-432. It is suggested that OK-432-skin test may provide the optimal dosage for local treatment of malignant fluids.

Ascitic Fluid↗
PubMed1993

How surrounds affect chromaticity discrimination.

Chromatic discrimination thresholds were measured with and without surrounds along two cardinal axes of chromaticity space. On one axis the level of short-wavelength-sensitive (SWS)-cone excitation was varied for constant long-wavelength-sensitive (LWS)-cone and medium-wavelength-sensitive (MWS)-cone excitations, and on the other axis there were equal and opposite changes in LWS-cone and MWS-cone excitations for constant levels of SWS-cone excitation. Results for two of three observers showed that with a dark surround, discrimination mediated by SWS cones was regulated by the level of SWS-cone excitation of the starting chromaticity, showing a function with the form of a threshold-versus-radiance function. For an equiluminant white or yellow surround, the discrimination for all three observers showed a minimum at the level of SWS-cone excitation of the surround, giving a V-shaped function for the white surround. An additional experiment with dimmer white surrounds indicated that while the minimum remained at the white point, the function gradually changed toward the shape with a dark surround. Discrimination thresholds mediated by LWS and MWS cones with a dark surround showed a minimum near the LWS-cone excitation of equal-energy white, giving a V-shaped function. The effect of yellow and white surrounds was to deepen the V. The data can be described by a model of chromatic discrimination incorporating a threshold term, a cone gain control, and an opponent gain control into two equations, one for SWS-cone discrimination and one for LWS-cone and MWS-cone discrimination.

Adult↗
PubMed1993

[A case of advanced gastric cancer responding to an FAP (5-FU, ADM, platinum compounds) combined chemotherapy].

An experience with an advanced gastric cancer patient with metastases to bilateral breasts, uterus, abdominal lymph nodes, bilateral axillary and supraclavicular lymph nodes, and bone marrow, responded extremely well to an FAP combined chemotherapy as reported here. The patients received four courses of 5-FU (370 mg/m2/day, for five days, continuous infusion), ADM (30 mg/m2 on day 1, i.v.) and CDDP (55 mg/m2 on day 1, i.v.) every 3 weeks in our hospital. This was followed by 7 months of outpatient therapy with 5-FU (550 mg/m2 on day 1, i.v.), ADM (30 mg/m2 on day 1, i.v.) and CBDCA (330 mg/m2 on day 1, i.v.) for every 4 weeks. The complete remission of the primary and metastatic lesions, that was confirmed by the histological examinations, was obtained after 10 months since the initial treatment started. The toxicity was generally moderate, however, the alopecia was severe. The patient has been living for 6 months without any signs of the recurrence after the complete remission obtained.

Adenocarcinoma↗
PubMed1990

[The expression of NCC-ST-439, a tumor marker, in human breast cancer patients].

The expression and serum level of NCC-ST-439, a tumor marker, has been investigated in 20 primary and 28 recurrent breast cancer patients, and the positive rate was found to amount to 21.1% in primary cases and 42.9% in recurrent cases, respectively, thereby indicating a positive correlation between the expression of NCC-ST-439 and the progression of the diseases. The accordance rate between NCC-ST-439 and CEA was 64.6%; in contrast, the rate between NCC-ST-439 and CA 15-3 was 82.1%, suggesting a difference in specificity against tumor between NCC-ST-439 and CEA. The change in the serum level of NCC-ST-439 in recurrent cases clearly correlated with the effectiveness of the therapy. These findings suggest that measurement of the NCC-ST-439 level, especially in combination with the CEA level, may be useful for the early detection and the monitoring of relapses in breast cancer patients.

Antigens, Tumor-Associated, Carbohydrate↗