Search PubMed⌕ Search

Biomedical subjects

M Shinagawa

Publications and source records attributed to M Shinagawa.

At least 127 records · Page 7Linked to original sources
PubMed1984

[Spongiform encephalopathy in mice inoculated with scrapie material of sheep origin].

The authors report spongy degeneration in experimental scrapie (second passage) in mice. The scrapie agent was originally isolated from Suffolk sheep imported from Canada and diagnosed histopathologically to be infected with scrapie by intracerebral inoculation into JCL/ICR mice. Ten female SIc/ICR mice, 4 weeks of age, were injected intracerebrally in the right frontal lobus with 20 microliter of 10(-1) or 10(-4) dilution of JCR/ICR mice brain homogenate involving scrapie agent. All animals showed signs of the advanced stages of the disease, clinically manifested by lassitude, arched backs, lethargy and paresis of hind quarters. They were sacrificed five to six months post inoculation, and sections of the brain and spinal cord were examined by light and electron microscopy. Focal symmetrical spongiform lesions were seen light microscopically in the cerebral mantle, thalamus, hypothalamus, midbrain, medulla oblongata, cerebellum and cervical mark. There was evidence that these lesions tended to be more intense in the mice inoculated a higher concentration of scrapie agent. Astrocytic proliferation was present in the deep layer of cerebral gray matter, white matter, corpus callosum, dorsal part of hippocampus and thalamus. No leukocytic infiltration was observed. Electron microscopically, the spongiform lesions were shown to be caused by vacuolation or swelling within the neuropil, and vacuolation and focal swelling in the neuronal perikaryon. The changes in the neuronal perikaryon were caused by enlargement of endoplasmic reticulum and cisterns of the Golgi apparatus, accompanied by spherical swelling of a part of the cytoplasm. The vacuolation near or within the neuron produced deformation of the cell contours and displacement of the nucleus.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Comparative sequence analysis of the inverted terminal repetition in the genomes of animal and avian adenoviruses.

The nucleotide sequences at the inverted terminal repetitions from two animal adenoviruses, infectious canine hepatitis virus and equine adenovirus, and from one avian adenovirus, CELO, were analyzed. DNAs from infectious canine hepatitis virus and equine adenovirus contain a homologous region which is 23 nucleotides long from the terminus. The first 17 nucleotides of this region are identical to the ones in human adenovirus type 2 DNA. The striking homologous sequence of 14 nucleotides, conserved in the inverted terminal repetitions of several human adenovirus strains and in simian adenovirus type 7, is only partially conserved in the two animal and one avian adenoviruses reported here.

Adenoviridae↗
PubMed1982

Physical mapping of the genome and sequence analysis at the inverted terminal repetition of adenovirus type 4 DNA.

The genome of adenovirus type 4 (Ad4), the unique member of Ad group E, has been mapped with nine restriction endonucleases. Comparison of the occurrence of restriction endonuclease cleavage sites on Ad2, Ad7, Ad12 and Ad4 indicates that there is very little homology between these serotypes. Sequence analysis at the ITR of Ad4 showed that the "CAT" box which is present in all the ITRs of Ad's so far sequenced is absent in Ad4. The length of 116 bp for the ITR of Ad4 is also different from that of other Ad subgroups.

Adenoviruses, Human↗
PubMed1982

Comparison of DNA sequences required for the function of citrate utilization among different citrate utilization plasmids.

The relatedness of DNA sequences encoding citrate utilization was examined by hybridization with a cloned DNA fragment from a citrate utilization (Cit) plasmid, pOH30221, and DNA of other Cit plasmids. This revealed that there are at least two groups of Cit plasmids: the Inc W Cit plasmids, which show homology with the probe, and the Inc H1 plasmids, which do not.

Base Sequence↗
PubMed1982

Studies on (n, alpha) recoils of 6Li and 10B in the reactor UTR-Kinki by gas phase electrodeposition.

The energies of recoil particles from (n, alpha) or (n, 2 alpha) reactions of Li and B were investigated by solid state detector and gas phase electrodeposition as previously reported on 228Th series. Nuclear reactor of UTR-Kinki was used as thermal neutron source. Particles from 6Li (n, alpha) 3T and 10B (n, alpha) 7Li were collected on a sheet of triacetate film by gas phase electrodeposition at atmospheric pressure. The film was etched with 6M-NaOH at 50 degrees C. The tracks thus obtained were taken as photographs with a microscope (X600). By counting the number of tracks on the film at various etching times, the energies of alpha-particles were evaluated according to the calibration curve of 227Ac series. Among various peaks of tract density, the two peaks having the evaluated values of 1.85 MeV for 6Li and 1.48 MeV for 10B agreed approximately with the theoretical values of 2.05 MeV and 1.47 MeV of alpha-particle energies for respective reactions.

Alpha Particles↗
PubMed1981

[Focusing chromatography using a dilute precipitation reagent--separation of 226Ra decayed nuclides by potassium fluoride (author's transl)].

The electrophoresis of 226Ra and it's decayed nuclides was carried out by using hydrochloric acid in the positive electrode cell and aqueous solution of potassium fluoride in the negative electrode cell. Experimental factors, i.e. concentrations of potassium fluoride and hydrochloric acid, intensity of electric field, duration for electrophoresis and pH value of the potassium fluoride solution etc. were examined. The sample solution was of 0.01 M hydrochloric acid with a tracer amount of 226Ra and 210Pb. Each of these nuclides was carrier free and was 4GB1/l(1 muCi/ml) in concentration. For the sake of autoradiography, a photoengraving film (Fujilith Ortho Film, TAC = 135) was made use of examining the locations of the separated radioactive bands obtained on the paper strip. Their beta and gamma radioactivities were detected as the film darkening on developing the film. According to the positions thus detected, the strip filter paper was cut into pieces and the species of radionuclides were determined by the measurements of energies and half-lives on beta and gamma rays. The locations of the separated alpha-radionuclides were decided by etching the surface of it's film with 6 M aqueous solution of sodium hydroxide and the species of radionuclides were determined by the solid state alpha-track detection method. As the result, the optimum conditions for the separation are to use 0.01 M hydrochloric acid in the positive cell and 0.005 M potassium fluoride of pH 6.2 in the negative cell, intensity of the applied electric field being 1000 V/30 cm, and electrophoresis time being 20 minutes. The proposed method gave good results for focusing and separating the radium series nuclides. Bands of 210Bi and 210Po were found on the positive electrode side, while the bands of 226Ra and 210Pb (containing 214Pb) were on the negative electrode side.

Chemical Precipitation↗
PubMed1980

The nucleotide sequence of the right-hand terminal SmaI-K fragment of adenovirus type 2 DNA.

The primary structure of the SmaI-K fragment of adenovirus type 2 (Ad2) DNA has been determined. This region includes one of the origins of DNA replication (Winnacker, 1978; Sussenbach and Kuijk, 1978). A leader sequence for an early mRNA in region 4 (Berk and Sharp, 1977; 1978) has also been mapped in this region. The comparison of the primary structure of this region in Ad2 DNA with the corresponding region in Ad5 DNA shows a remarkable homology which may be significant in view of the fact that Ad2 and Ad5 DNAs can interchangeably function in the in vitro replication system of Challberg and Kelly (1979).

Adenoviruses, Human↗
PubMed1980

Comparative sequence analysis of the inverted terminal repetitions from different adenoviruses.

The comparative nucleotide sequences of the region of inverted terminal repetition from a representative member of group C (nononcogenic), group B (weakly oncogenic), and group A (highly oncogenic) adenoviruses are analyzed. Our data show that (i) the length of this unique region increases with the oncogenicity of the serotype, (ii) a unique homologous region--14 nucleotides long--is present exactly at the same distance from the terminus, and (iii) a hexanucleotide sequence, T-G-A-C-G-T, is present at the site where the terminal repetition diverges.

Adenoviruses, Human↗
PubMed1980

Application of a continuous channel electron multiplier for measuring gaseous tritium at low pressures.

Some fundamental studies on the application of a continuous channel electron multiplier (channeltron) for monitoring gaseous tritium present in an evacuated vessel at low pressures below 10(-4) Torr were carried out. The results showed that at the tritium pressures lower than 10(-6) Torr the tritium counting rate measured by the channeltron increased linearly, in practice, with increasing tritium pressure, as was expected by assuming that the interactions between beta-particle emitted from tritium and the vessel wall and gaseous molecules during the migration of beta-particle to the channeltron can be ignored. However, in the range of pressures over 10(-5) Torr the measured tritium counting rate was found to be getting smaller than the expected with increase in tritium pressure. This is presumably due to the absorption and scattering of beta-particles by gaseous tritium.

Gases↗
PubMed1980

[Study on focusing chromatographic simultaneous determinations of 226Ra and its daughter nuclides by means of solid state alpha-tracks detection and beta-autoradiography (author's transl)].

In order to detect to radioactive band on the paper strip developed by focusing chromatography, plate-making-film was used for the autoradiography and beta-spots were photographed. Thereafter the film was etched with sodium hydroxide solution to find the alpha-tracks. Paper strip used for the sample was prepared by the precipitation focusing chromatography of 226Ra and its daughter nuclides using HCl-KF solution as a developer. The film used was not high in its beta-sensitivity, but because of its high resolution good photographic results were obtained according to the intensity of beta-activity when the proper conditions of photographic development were fulfilled. The simple alpha-spectrometry was made possible by counting the numbers of tracks according to the etching depth of the film. The film was hard and thick enough for etching with 6M sodium hydroxide solution at 50 degrees C for more than 50 hrs to measure the depth of tracks.

Alpha Particles↗
PubMed1979

Fundamental study on decontamination of tritium from gaseous phases by copper oxide.

Some fundamental studies on removal of tritium from gaseous streams by a small column of copper oxide were carried out. An about 10 cm length of column packed with 100 g of copper oxide was examined on the conversion ratios of hydrogen and tritium into water. The experiment with hydrogen of 0.1% in argon showed that the logarithmic plot of remaining ratio of hydrogen by passing through the column is proportional to the reciprocal of gas flow rate and to the length of oxide column. The oxide column was also used for treating tritium-bearing waste gas from an evacuating system of alpha D-T neutron generator. It was observed that at column temperatures lower than 450 degrees C the conversion ratio of tritium in the waste gas into water is considerably smaller than that of hydrogen of 0.1% in argon.

Copper↗