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Biomedical subjects

O Nakamura

Publications and source records attributed to O Nakamura.

At least 127 records · Page 7Linked to original sources
PubMed1982

[The role of immune RNA in the immunotherapy of malignant brain tumor (author's transl)].

At present, nonspecific immunotherapy using BCG or Picibanil is popular as an immunotherapy for malignant brain tumor. On the other hand, specific immunotherapy using lymphocytes which play an important role in the passive transmission of tumor immunity is also performed. But this therapy has some disadvantage such as the problem of blocking factor or histocompatibility. To compensate for this disadvantage, specific immunotherapy using the chemical mediater, immune RNA, extracted from immunized lymphocytes has started. We extracted immune RNA from the spleen of immunized rat using phenol and SDS, and observed the effect of normal lymphocytes preincubated with immune RNA in vitro and in vivo experiments. In in vitro experiment, following results were obtained. (1) Normal lymphocytes incubated with immune RNA revealed a significant cytotoxicity and this effect was disappeared by the pretreatment of immune RNA with RNase. (2) Cytotoxic effect of immune RNA seemed to be a tumor specific response. (3) Not only syngeneic RNA, but also xenogeneic RNA were effective. In addition to these results, we decided the optimal condition in which immune RNA transferred the cell mediated cytotoxicity to normal lymphocytes. Next, we tried the purification of immune RNA by way of sucrose density gradient centrifugation method and oligo (dT) cellulose affinity chromatography method. Active fraction of immune RNA was contained in 8-16 S fraction and in poly (A) containing fraction. As in vivo experiment, we injected immune RNA incubated lymphocytes intravenously to brain tumor-bearing rats and observed for death daily. In this experiments, significant prolongation of mean survival time was recognized in the group treated with immune RNA. We now consider the clinical application of immune RNA for malignant brain tumor by the following method: immune RNA is obtained from the lymphocytes of sheep which has immunized with patient's tumor cells. And then patient's own lymphocytes strengthened by incubation with immune RNA is injected intratumorally by way of Ommaya's reservoir. To do this therapy safely and effectively, further purification of immune RNA and solution of its physiochemical characteristics will be necessary.

Animals↗
PubMed1982

[Schmidt Ruppin-D-ASV-induced primary rat brain tumor model for therapeutic screening].

It is important to evaluate the therapeutic and side effects of new therapy for malignant brain tumors in an adequate animal model prior to its initial clinical investigation. For decades, neurooncologists have argued for the use of primary, autochthonous tumors rather than transplanted tumors such as C 6 glioma cells and 9 L gliosarcoma cells. But unfortunately, no spontaneous animal astrocytomas are currently available as usable models. So we tried to establish the model of primary, autochthonous avian sarcoma virus-induced rat gliomas for experimental chemotherapy and immunotherapy. The present study was undertaken to determine the incidence and histologic pattern of tumors and the mean survival time of the animal model used. It was found that the intracerebral inoculation of 2 X 10(6) FFU/5 microliter of infectious cell free homogeneous subgroup D Schmidt-Ruppin avian sarcoma virus (SR-D-ASV) into 3-day-old inbred Fischer 344 rats induced small sized tumors in all rats 20 days later. The mean survival time of inoculated rats were 58.7 +/- 12 days. As to the classification of SR-D-ASV induced brain tumors in Fischer rats, astrocytoma was 70.6% (protoplasmic astrocytoma 23.5%, fibrillary astrocytoma 47.1%), sarcoma 17.6%, and mixed astrocytoma and sarcoma 11.8%. In conclusion, this SR-D-ASV induced tumor in the rat fulfilled the following criteria for the desirable animal model: (1) Spontaneously arising. (2) Glial origin. (3) Intraparenchymal growth. (4) Uniformly fatal within reasonable time period. Statistic evaluation of the effects of chemotherapy and immunotherapy was considered to be possible.

Animals↗
PubMed1982

[Effect of interferon inducer (poly ICLC) in the treatment of malignant brain tumor (author's transl)].

Interferon inducing activity, antitumor activity and toxicity of poly ICLC (poly IC stabilized with poly L-Lysine and carboxymethyl cellulose) in rodents were studied. SD strain rats were injected intravenously with poly IC or poly ICLC. Interferon in rat plasma was assayed by a plaque reduction method using stomatitis virus. The peak level of plasma interferon of the poly ICLC injection rat was as high as that of poly IC injection rat, and in the former, high level of plasma interferon persisted for 4-12 hours. Next, brain tumor-bearing rats were treated intravenously with poly ICLC and observed for death daily. Weekly treatment with 1 mg/kg of poly ICLC increased the mean survival time although no antitumor effect was observed with poly IC. The LD 50 value of poly IC was 33.5 mg/kg, and that of poly ICLC was 18.6 mg/kg and as to poly ICLC administration, no remarkable side effect was recognized below the dose of 1.5 mg/kg. In clinical trials, poly ICLC was given intravenously at the dose of 0.05-0.2 mg/kg to 9 patients with malignant brain tumor. (6 patients were glioblastoma, 1 was astrocytoma, and 2 were ependymoma.) In 2 patients, poly ICLC was administered once, in 2 patients twice, in 2 patients 3 times, and in 3 patients more than 5 times. The interval of each administration was 7 days. Poly ICLC induced high level of serum interferon (more than 100 reference unit/ml) in all patients and over 100 unit/ml of interferon was maintained for 24 hours. The highest interferon titer induced was 875 unit/ml. The most frequently encountered toxic reaction was fever, which occurred in all cases. The mean peak temperature elevation was 1.9 degrees C, which usually occurred 4-8 hours after drug administration. Modest hypotention was detected in one case. Leucopenia was detected in 3 cases. These abnormalities were all modest, and improved in a few days. As to the effect of poly ICLC, neurological improvement was recognized in 3 cases, and in one of them, remission on CT scan was also recognized.

Adult↗
PubMed1982

[Computed tomographic measurement of regional cerebral blood flow by xenon enhancement (author's transl)].

The present study was conducted to overcome some of disadvantages of cerebral blood flow study by radionuclide, such as poor regionality of flow values and errors involved in pathological brains. Serial CT scanning was carried out during and after inhalation of 50 to 70% non-radioactive xenon in humans. Diffusible gas with high atomic number enhanced gray matter first 19 +/- 4 HU (mean +/- SD) on an average in Hounsfield unit (HU) and later white matter 24 +/- 4 HU. In seven normal subjects, blood flow in gray matter was 82 +/- 11 and that in white matter 24 +/- 5 ml/100 gm/min. Partition coefficient which is not readily obtainable by radionuclide study was 0.9 +/- 0.1 in normal gray matter and 1.4 +/- 0.2 in normal white matter. Two cases were presented to show k-map (clearance rate), lambda-map (partition coefficient) and CBF map, which displayed images of values calculated automatically, in black and white or color on CRT. The first case was a patient with metastatic brain tumor from lung in the left parietal region. The blood flow of the tumor was close to that of gray matter, whereas blood flow of edematous white matter surrounding the tumor was decreased to below 10 ml/100 g/min with partition coefficient ranged from 0 to 0.9. The second case was presented to demonstrate the resolution of the blood flow map obtained by this method. Multiple lacunar infarcts of the basal ganglia and white matter in the size of 1 to 3 mm, which were hardly identified on regular CT picture, were well visualized on CBF map. This method appeared to have several advantages over conventional isotope method and to provide useful clinical and research informations.

Aged↗
PubMed1981

Concomitant appearance of antibodies to two viruses in cerebrospinal fluid of an infant with acute encephalitis.

Acute encephalitis developed in a 5 1/2-month-old infant with a previous history of uncomplicated measles at 4 months of age. The patient survived his acute illness with resultant severe neurological sequelae. The serum complement fixing antibody titer for herpes simplex virus in the early phase of the illness was less than 1:4, and increased significantly to 1:64 in the convalescent phase. Antibody was also demonstrated in the cerebrospinal fluid. Antimeasles antibody was found in the cerebrospinal fluid in the early convalescent stage and remained at a detectable level for at least 1 month. Moreover, at least 71% of the total protein in the cerebrospinal fluid was IgG. Although brain biopsy for viral isolation was not performed, the most probable diagnosis was herpes simplex virus encephalitis, and the concomitant appearance of measles antibody in the cerebrospinal fluid may have been due to leakage of measles antibody from the blood into the cerebrospinal fluid due to disturbance of the blood-brain barrier.

Acute Disease↗
PubMed1979

The specific, diverse effects of purine and pyrimidine nucleoside-5'-di(tri)-3'-diphosphates on the eucaryote translation system in vitro.

All the eight 5'-di(tri)-3'-diphosphates of four common ribonucleosides were prepared by the enzymic pyrophosphoryl transfer catalysed by Streptomyces adephospholyticus ATP:nucleotide pyrophosphokinase (E.C.2.7.6.4) form dATP to the respective 5'-phosphates, and their effects on the translation of mRNAs by a wheat germ system in vitro were studied. (p) ppPupp decreased the total 14C-leucine incorporation directed by a rat liver mRNA whereas (p) ppPypp did not. With a silkworm pupa ovary mRNA, distinctly reverase results were obtained. Gel electrophoretic profiles of the translation products disclosed the mRNA species-specific stimulatory or inhibitory effects for each of the polyphosphates tested.

Adenine Nucleotides↗
PubMed1978

Further studies of the prospective fates of blastomeres at the 32-cell stage of Xenopus laevis embryos.

Each blastomere in the marginal zone of Xenopus laevis embryos at the 32-cell stage was stained with Nile blue sulphate. Only specimens with the typical arrangement of blastomeres of morulae of this species were used, and special care was taken to prevent the dye from spreading to neighbouring cells and to determine the extent of stained areas. The prospective fate of each blastomere was studied and a new fate-map of the 32-cell embryo was drawn by tracing the movement of stain during the course of further development.

Animals↗