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Biomedical subjects

Y Kodera

Publications and source records attributed to Y Kodera.

At least 307 records · Page 17Linked to original sources
PubMed1984

Backscatter from metal surfaces in diagnostic radiology.

Backscatter from four commonly used metals (aluminum, lead, copper, and iron) was measured under diagnostic imaging conditions, using screen-film systems as detectors. The results indicate that for an 80-kV filtered beam and Par Speed/XRP system, backscatter increases as aluminum (Al) thickness increases until it reaches a plateau of approximately 12% at 50 mm Al. The amount of backscatter from any of these four metals increases as the tube voltage is raised from 60 to 115 kV. Measured backscatter depends strongly on the screens used, possibly due to their attenuation and energy response. Backscatter from aluminum was significantly greater than that from the other metals tested.

Aluminum↗
PubMed1984

Absolute speeds of screen-film systems and their absorbed-energy constants.

Absolute speeds (mR-1) of screen-film systems were determined accurately and precisely from ten independent measurements over a six month period at several beam qualities that included both scatter and scatter-free conditions. The absorbed x-ray energies in the screens that yielded a net film density of 1.0 were obtained by means of Monte Carlo calculations and a semianalytical method. The standard deviations of the calculated absorbed x-ray energies at different beam qualities were less than 10% for all of the screen-film systems studied. Therefore, the absorbed x-ray energy that produces a given film density for these systems can be regarded as constant at the beam qualities used. Quantum absorption and fractional energy absorption of the screens were also calculated. The predicted Wiener spectral values based on the number of photons detected were compared with the measured Wiener spectral values of the screen-film systems.

Radiographic Image Enhancement↗
PubMed1984

Sixteen adult patients with acute leukemia treated by chemotherapy, total body irradiation and allogeneic marrow transplantation.

Since 1976, 16 adult patients with acute leukemia have been treated by chemotherapy, total body irradiation (TBI) and allogeneic bone marrow transplantation (BMT) in the medical school hospital and the satellite hospitals of Nagoya University. The first group of 10 patients were given marrow grafts at the time of leukemic relapse and the second group of six patients were given the grafts in the period of remission of their disease. For the first group (ALL/ANLL 2:8, age (median) 33, M/F 8:2), HLA-identical donor cells (25 x 10(7)/kg [median]) were infused after the patients were conditioned with NSC D 245382 (ACNU) or daunorubicin, cyclophosphamide (CY) and a single shot of 1000 rad of TBI. For the second group (ALL/ANLL 4:2, age (median) 20, M/F 5:1), HLA-identical donor cells (22 x 10(7)/kg [median]) were infused after the patients were conditioned with CY and fractionated (250 rad x 4) TBI. All the patients were isolated in a laminar air flow room (LAF) after gut and skin decontamination. Engraftment of donor cells was confirmed in 15 out of the 16 patients. Febrile periods in LAF and the days required for platelet transfusion were prolonged in the first group. All the patients in the first group died within 12-214 days after BMT because of interstitial pneumonitis (7 patients) or bacterial infection (3 patients). On the other hand, five out of six patients in the second group are alive 84-540 days after BMT. For the surviving patients, the complications of chronic graft versus host disease, viral infections, tuberculosis, hepatitis, hemorrhagic cystitis and recurrence of leukemia are now the problems. It can be stated that the patient's clinical condition at the time of BMT is one of the most essential factors for the success of BMT although the effects of other variables, such a change in the conditioning regimens of the supportive care, must also be carefully analyzed.

Acute Disease↗
PubMed1984

Induction of transplantation resistance to murine L1210 leukemia cells in BCG-primed mice by immunization with tuberculin protein-coupled L1210 cells.

By priming with Bacillus Calmette-Guérin (BCG) and subsequent immunization with L1210 leukemia cells to which purified protein derivative of tuberculin (PPD) had been coupled, a resistance to L1210 leukemia but not to syngeneic P388 leukemia was induced in DBA/2 and CDF1 mice. Separate injections of mitomycin C-treated L1210 cells and PPD also induced the resistance, but it was established only when they were administered simultaneously. PPD-coupled cells seemed to play a more important role than BCG, since the immunoprophylaxis was observed when L1210 challenge was made at the sites of PPD-L1210 immunization, but was not observed when L1210 challenge was made at the sites of BCG priming.

Animals↗
PubMed1984

[Treatment of hematological malignancies with recombinant leukocyte A interferon (rIFN-alpha A)].

Twenty-three cases of hematological malignancies (18 plasma cell neoplasm, 2 leukemia and 2 malignant lymphoma) were treated with recombinant human leukocyte interferon (rIFN-alpha A). Among plasma cell neoplasms, excellent and good responses were obtained in 1 case of IgG myeloma and 1 case of Bence-Jones myeloma respectively and fair response was obtained in 5 other cases. Response rats was 11.4%, or 38.9% if fair response was included. Partial remission was obtained in 1 case of chronic lymphocytic leukemia. In one of 2 cases of acute lymphoblastic leukemia, marked reduction of peripheral leukemia cells was noted. Side effects included fever (65%), malaise (20%), nausea-anorexia (43%), leukopenia (52%) and thrombocytopenia (52%). However, all were not serious and disappeared quickly after discontinuation of rIFN-alpha A.

Adult↗
PubMed1983

Effect of collimators on the measurement of diagnostic x-ray spectra.

One of the difficulties in the measurement of diagnostic x-ray spectra is the high fluence rate of the photons, which may exceed the capability of the spectrometer system. Pinhole collimators are often used which reduce the count rate to an acceptable level. The measured spectrum, however, may be distorted due to the penetration of photons through the collimator material. In this study, the effects of collimators on the measured spectra were evaluated. As an indicator of collimator performance, we determined the transmission equivalent aperture (TEA), through which a portion of the incident photons impinge on the detector. The dependence of the TEA on the geometry of collimation, pinhole area, collimator material and thickness, detector area and incident x-ray energy was investigated. The penetration correction factors (PCF) for the measured spectra were also derived. We obtained good correspondence between the theoretical spectra and the measured spectra which were corrected for collimator penetration by means of the calculated PCFS. Our results indicate that diagnostic x-ray spectra generated at high tube current can be measured if one uses a collimator with a small aperture together with its PCF.

Mathematics↗
PubMed1983

Evaluation of cassette performance: physical factors affecting patient exposure and image contrast.

Physical properties of four radiographic cassettes were investigated in combination with various screen/film systems. These properties included (a) transmittance of monoenergetic x rays over 14-96 keV and comparison with predictions based on attenuation coefficients; (b) relative patient exposure from 60 to 120 kV (from phantom measurements) and correlation with predictions based on measured transmittance as well as average energies and angles of incident radiation; and (c) amounts of scatter from various cassette materials and comparison with Monte Carlo calculations. The results provide a model of performance based on quantitation of cassette effects on system speed and image contrast. Carbon-fiber cassettes required the lowest patient exposure, produced the least scatter, and (in low-scatter situations) were capable of increased image contrast.

Aluminum↗
PubMed1983

[The clinical effects of a new antiviral 9-(2-hydroxyethoxymethyl) guanine (aciclovir) against herpes virus infections].

The clinical effects of a new anti-viral 9-(2-hydroxymethoxymethyl) guanine (Aciclovir) against Herpes virus infections have been investigated. The patients had malignant tumours or auto-immune disease complicated by shingles and chicken pox due to Vaicella zoster virus (VZV) (43 cases), Herpes simplex virus (HSV) (10 cases) and 9 cases which were clinically diagnosed as Herpes, though the virus was not confirmed as the causative agent. As a general principle the dosage of Aciclovir was 5 mg/kg, t. i. d. for 5 days by slow intravenous infusion. The clinically effective rate against VZV was 93%, being excellent in 42% and against HSV it was 80%, being excellent in 40% and when the results of the cases of unknown origin were included it was excellent in 40% and the cumulative effective rate was 88%. Concerning the efficacy in reduction of pain, swelling, disappearance of vesicles and new scab formation, the effect was most noticeable after the third day of treatment. Treatment given early in the disease is likely to provide better results. Concerning side effects, one of 62 patients had proteinuria and the other had a drug rash and an abnormal liver function test. It is likely that the combination of treatment and the primary disease had some influence, but the cause/effect relationship to Aciclovir treatment is not clear.

Acyclovir↗
PubMed1983

[Clinical study on the effect of human lymphoblastoid interferon in multiple myeloma].

Ten patients with multiple myeloma were treated with human lymphoblastoid interferon (HLBI). The dosages used were 3 X 10(6) IU to 6 X 10(6) IU of HLBI intramuscularly daily. Out of eight evaluable patients, one partial remission and 3 minor response were observed. More than half patients experienced fever exceeding 38 degrees C and mild myelosuppression. Other toxic effects consisted of anorexia, malaise, liver dysfunction and skin rash. On the basis of our preliminary study, we conclude that HLBI is an effective agent against multiple myeloma.

Aged↗
PubMed1983

Clinical use of bioclean rooms in Japan with special reference to medical isolators.

A survey on the clinical use of medical isolators was undertaken by sending out a questionnaire to the major medical and pediatric oncology services in Japan. As of December, 1981, laminar-air-flow rooms (LAFR) were installed in hospital rooms of 79 institutions. To date, 68 patients with leukemia, 12 with malignant lymphoma and 10 with aplastic anemia have been treated in LAFR for the purpose of bone marrow transplantation. So far, 501 patients with leukemia, 24 with malignant lymphoma and 14 with solid tumor have been treated in LAFR for the purpose of intensive chemotherapy. A variety of items as to the clinical use of medical isolators, such as type of LAFR, decontamination of isolators, protective clothing, food and gut sterilization and attending staff were surveyed. There remain many problems in the use of medical isolators, such as the high cost of establishing and maintaining a bioclean system, the shortage of nursing staff, the lack of space and accessory equipment and so on. Nevertheless, the author will continue to recommend isolation with a physical barrier, protective clothing for attending staff, pathogen-free food and oral prophylactic anti-microbial agents.

Bacterial Infections↗
PubMed1980

Mixed lymphocyte-tumor cell reaction between remission lymphocytes and autochthonous leukemia cells and its relationship to the prognosis of acute leukemia.

The mixed lymphocyte-tumor cell reaction (MLTR) between peripheral lymphocytes and cryopreserved autochthonous leukemia cells was studied in 36 adult patients with acute leukemia after complete remission as a result of chemotherapy. In 20 patients the lymphocytes showed a significant blastogenic response to autochthonous leukemia cells. Eleven out of 18 patients with acute myeloblastic leukemia and 4 out of 5 with acute monocytic leukemia showed positive MLTR, whereas 5 out of 13 with acute lymphoblastic leukemia gave a positive reaction. Cryopreserved leukemia cells of the patients with not only positive but also negative MLTR were able to stimulate allogeneic lymphocytes, except in one case. The relationship between MLTR and the prognosis of leukemia was analyzed in 30 patients who were alive more than 6 months after diagnosis. No apparent correlation was observed between MLTR and the survival time from diagnosis.

Acute Disease↗