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Biomedical subjects

S Kaneda

Publications and source records attributed to S Kaneda.

At least 91 records · Page 5Linked to original sources
PubMed1983

Nucleotide sequence of Dictyostelium small nuclear RNA Dd8 not homologous to any other sequenced small nuclear RNA.

The cellular slime mold Dictyostelium discoideum, a lower eukaryote, was shown to contain several species of small nuclear RNA (Takeishi, K., and Kaneda, S. (1981) J. Biochem. (Tokyo) 90, 299-308; Wise, J. A., and Weiner, A. M. (1981) J. Biol. Chem. 256, 956-963). One of these RNAs, Dd9 or D2, was sequenced and found to be homologous to mammalian nucleolar U3 RNA. In the present study, the nucleotide sequence of another Dictyostelium small nuclear RNA Dd8 was determined by direct analysis. The sequence is: (formula; see text) Dd8 RNA contains high proportions of A (34%) and U (30%). No modified nucleotide could be detected in the internal region. Computer-assisted analysis of sequence homology indicated that Dd8 RNA is not homologous to any other small nuclear RNA species sequenced so far.

Base Sequence↗
PubMed1981

Isolation and characterization of small nuclear RNAs from Dictyostelium discoideum.

Low molecular weight RNAs were isolated from nuclei of the cellular slime mold Dictyostelium discoideum AX-3. Analysis of the RNAs by polyacrylamide gel electrophoresis showed that the vegetative cell nuclei contained, besides tRNA (Dd1), 5S RNA (Dd4), and 5.8S RNA (Dd7), at least 7 small RNA species (Dd3, Dd5, Dd6, Dd8, Dd9, Dd10, Dd11) of 4S to 8S as major components and that the 7 small RNAs were localized mainly in the nucleus and had no poyl(A) sequence. These nuclear RNA species were metabolically stable, as shown by a chase experiment. Dd6, Dd8, and Dd9 had similar gel electrophoretic mobilities to those of the small nuclear RNA species U1, U2, and U3, respectively, of rat liver. Analysis of the 5'-terminus of these RNA molecules with tobacco acid phosphodiesterase suggested that Dd6, Dd8, and Dd9 each contain a cap. Sequence analysis of the 3'-end labeled Dd9 RNA showed that the 3'-terminal region sequenced had sequence homology with that of rat Novikoff hepatoma U3 RNA. These results indicate that Dictyostelium nuclei contain a set of small nuclear RNA species which is structurally similar to that in mammalian cells. No qualitative differences were detected between the small nuclear RNA species of vegetative and early differentiating cells.

Animals↗
PubMed1981

Influence of pattern and red color on the photoconvulsive response and the photic driving.

Patients, 232 epileptics and 98 nonepileptics, were examined for photoconvulsive responses and photic driving, by using a stroboscope with a) a printed pattern (dots or grating) and b) a red plastic plate. The stimuli given were (1) dot pattern 5 Hz IPS, (2) red 5 Hz IPS, (3) grating pattern 15 Hz IPS, and (4) red 15 Hz IPS, with eyes open. Photoconvulsive responses evoked by (3) and (4) were 6.6% and 5.1%, respectively, which were significantly higher than those obtained from a control group flickered with ordinary white light, 15 Hz IPS, (1.1% and 0.9%, with eyes open and closed, respectively). High amplitude photic driving over 50 microV evoked by (1) occurred in 34.9% of the patients and by (2) 22.7%; these were significantly higher than in the control group with ordinary white flicker (12.5% and 5.2%). Similar stimuli of (1) to (4) with a constant brightness of 20 cd/m2 provided by a visual stimulator SLS-5100 were given in the same way. Photoconvulsive response evoked by 15 Hz flickering grating pattern occurred in 7.8% and by 15 Hz red flicker in 8.1%; the rate being slightly higher than, but not significantly different from, the above results. High amplitude photic driving evoked by 5 Hz flickering dot pattern and 5 Hz red flicker were 29.3% and 21.2%, respectively. These values were slightly lower than, but not significantly different from, the above results. It was concluded that the flicker stimulation with either pattern or red color is more potent in eliciting photoconvulsive responses (15 Hz) and photic driving responses (5 Hz) than conventional flicker. Furthermore, patterned IPS and red IPS showed almost the same activation effect on photoconvulsive responses and high amplitude photic driving as that of the comparable stimuli provided by a visual stimulator SLS-5100.

Adolescent↗
PubMed1981

Species difference in liver microsomal and cytosolic enzymes involved in mutagenic activation of N-hydroxy-N-2-fluorenylacetamide.

The mutagenic activations of N-hydroxy-N-2-fluorenylacetamide (N-OH-2-FAA) by subcellular fractions of the livers of the Sprague-Dawley rat, C57BL mouse, Hartley guinea pig, Syrian golden hamster, and Macaca fuscata fuscata monkey were examined for sensitivity to paraoxon, which inhibits a deacetylase but not an arylhydroxamic acid acyltransferase. The mutagenic activation by liver microsomes was almost entirely mediated by a paraoxon-sensitive enzyme in all the animals tested. In contrast, the mutagenic activation by liver cytosol was mediated mostly by a paraoxon-sensitive enzyme in mice and guinea pigs, mostly by a paraoxon-resistant enzyme in rats and hamsters, and by both enzyme types in the monkey. In rats and guinea pigs, attempts were made to identify the enzymes causing mutagenic activation in the liver cytosol by a comparison of the elution positions of these enzymes in gel filtration and DEAE-cellulose column chromatography with those of known enzymes. In the rat liver cytosol, the mutagenic activation was mediated not only by acyltransferase but also by an unknown enzyme, which was resistant to paraoxon and differed from acyltransferase in chromatographic behavior. In the guinea pig liver cytosol, the activation was due to deacetylase activities, which could be separated into four fractions by gel filtration. These data indicate that species differ in the kinds of liver cytosolic enzymes involved in mutagenic activation of N-OH-2-FAA but not in the kind of liver microsomal enzyme involved.

2-Acetylaminofluorene↗
PubMed1981

[Cast fractures of dental Ni-Cr alloys (author's transl)].

Cast fractures of Ni-Cr alloys were investigated by means of scanning electron microscopy, energy dispersive X-ray spectrometry, electron-probe microanalysis, density measurements, setting and thermal expansion measurements and compressive tests. Three-Ni-Cr alloys for crowns and bridges were cast in spiral configurations by an argon-arc pressured type or an induction argon-pressured type-casting machine. The amount of cast fracture increase with an increase in cast temperature, but not with an increase of holding time at cast temperature. Ni-Cr alloys have more cast fractures in a phosphate-bonded investment than in a gypsum-bonded cristobalite investment. Fracture surfaces have an exposed dendrite structure, indicating the presence of cast porosity. The trigger of cast crack can be a cast porosity and the propagation of crack to fracture may be mainly due to the strength of investments.

Chromium Alloys↗
PubMed1979

Low molecular weight nuclear RNA species in Dictyostelium discoideum.

Low molecular weight nuclear RNA (snRNA) species present in Dictyostelium discoideum Ax-3 cells were examined by electrophoresis in polyacrylamide slab gels. Dictyostelium nuclei were found to contain almost as many snRNA species as mammals and their electrophoretic pattern was similar to that of snRNA in mammalian cells. The same results were obtained with snRNA prepared using Cemusol NPT-12 as a detergent for cell lysis instead of Nonidet P-40 used for most RNA preparations.

Cell Nucleus↗