Showing papers by "University of Tsukuba published in 1981"

Matched pairs of groups and bismash products of hopf algebras

Abstract: (1981). Matched pairs of groups and bismash products of hopf algebras. Communications in Algebra: Vol. 9, No. 8, pp. 841-882.

Mechanism of growth promotion of mouse lymphoma L1210 cells in vitro by feeder layer or 2-mercaptoethanol.

Abstract: Mouse lymphoma L1210 cells require some thiol compounds (such as 2-mercaptoethanol) or feeder layer cells for their growth in normal culture media in vitro. We found that feeder layer cells (human diploid fibroblast IMR-90) constantly produce thiol compounds; cysteine was the major thiol compound accumulating in the culture medium. In the culture medium of L1210 cells, added cysteine was rapidly oxidized and was toxic to the cells at high concentrations. However, cysteine promoted growth of L1210 cells when it was added repeatedly to the medium at low concentrations. These results show that the major role of feeder layer cells is to provide cysteine continuously. The glutathione content of L1210 cells depended largely on the cysteine concentration in the medium. In normal culture media containing cystine but not cysteine, the cellular glutathione content decreased notably within a few hours. Cysteine had to be supplied repeatedly to keep the content high. Cystine promoted the cellular glutathione content at unphysiologically high concentrations. These results were attributable to the extremely low uptake rate of cystine by the cells as compared with that of cysteine. In the presence of 2-mercaptoethanol, the uptake of radioactive cystine by the cells was increased and a high cellular glutathione level was maintained. A thiol-independent variant of L1210 took up cystine far more rapidly than L1210. From these results we concluded that the deficiency of the cystine uptake limits the growth of L1210 cells in normal culture media.

Descending projections from the spinal and mesencephalic nuclei of the trigeminal nerve to the spinal cord in the cat. A study with the horseradish peroxidase technique

Abstract: Descending projections from the spinal (Vsp) and the mesencephalic nuclei (Vme) of the trigeminal nerve to the spinal cord were studied by means of the retrograde horseradish peroxidase technique in the cat. The number of labeled neurons was largest in the case of high cervical injections and decreased as the injections were placed caudally. Small laminae III and IV neurons of the nucleus caudalis (Vc) were labeled ipsilaterally following injections placed as caudally as the middle cervical segments (C4-C5). Lamina I (marginal) neurons of the Vc were labeled ipsilaterally after injections at the middle thoracic level (T6) but those of C1 were labeled after lumbar injections (L3). Lamina V neurons of C1 and the medullary counterparts were labeled bilaterally after injections placed caudally to thoracic segments. A few small neurons were labeled in the ipsilateral nucleus interpolaris (Vi) after injections placed as caudally as the middle cervical segments (C6). Among the subdivisions of the Vsp, the labeled neurons were most numerous in the nucleus oralis (Vo). They were medium-sized and large, and appeared bilaterally, with an ipsilateral predominance at the level of the superior olive. The great majority projected to the cervical segments but a few also projected to the lower cervical to the thoracic segments (C8-T9). Neurons of the Vme projected ipsilaterally to the upper cervical segments (C1-C3). No projections were found from the principal sensory nucleus. The present study suggests that the trigeminospinal projections of the Vsp and the Vme are composed of various cells of origin and thereby subserve not only the trigeminospinal reflex but other unknown functions.

Onset of synapse formation in the human spinal cord

Abstract: The time of onset of synapse formation was examined in the cervical spinal cord of eight human embryos ranging from 4 (8 mm in crown-rump length) to 6 (22 mm) weeks of ovulation age The first synapses were found in the motor nucleus of a 10-mm embryo (Streeter's horizon XV) They contained only a small number of synaptic vesicles and had asymmetrical membrane thickening, with thicker postsynaptic membranes than presynaptic ones With the exception of an occasional axosomatic synapse, nearly all synapses found in a 10-mm embryo were axodendritic In an 11-mm embryo (Streeter's horizon XVI), synapselike contacts (SLC) were found in the dorsal marginal layer They contained a small number of synaptic vesicles and had "reversed membrane specialization" with prominent presynaptic membrane densities The number of SLC decreased in older embryos Judging from the morphological characteristics of membrane specializations and the temporal decrease in number, SLC are considered to be either transient synapses on the borderline cells or axoglial synapses Synapses in the regions outside the motor nucleus first appeared in the dorsal marginal layer of a 14-mm embryo (Streeter's horizon XVII)

Spinocerebellar projections to lobules I and II of the anterior lobe in the cat, as studied by retrograde transport of horseradish peroxidase.

Abstract: Spinocerebellar tract (SCT) neurons projecting to lobules I and II of the cerebellar anterior lobe were identified by the retrograde horseradish peroxidase technique in the cat. Instead of a conventional stereotaxic approach, we removed ventral parts of the vermis of the posterior lobe and approached the posterior aspect of lobule I through the fourth ventricle. Under direct visual guidance, discrete injections were made into lobule I or lobule II with a glass micropipette. Neurons projecting to lobule I were located mainly in the central cervical nucleus (CCN), the medial part of lamina VII of L6 to the caudal segments, and in lamina VIII of S2 to the caudal segments (with crossed ascending axons). The latter two groups correspond to the medial lamina VII group of the lumbar to the caudal segments and the ventral horn group of the sacral-caudal segments of our previous studies. A small number of Clarke column neurons (with uncrossed ascending axons) also projected to lobule I. All of these neuronal groups projected to lobule II. In addition, large neurons in lamina V and in the border between laminae IV and V from S2 to the caudal segments projected to sublobule IIA, and more numerously to sublobule IIB (with crossed ascending axons). They belong to the dorsal horn group of the sacral-caudal segments of our previous studies. Spinal border cells (with crossed ascending axons) projected to sublobule IIB, and a small number, to sublobule IIA. It was suggested that the CCN neurons project more densely to the median region whereas Clarke column neurons project to the lateral part of these lobules.

Itaconic acid fermentation by a yeast belonging to the genus Candida.

Abstract: Many yeasts were isolated from natural sources in the tropics and subtropics by enrichment culture technique, using medium which contained a surfactant. The medium was acidified with citric acid. A strain S–10 belonging to the genus Candida was found to produce itaconic acid. Under suitable conditions in shake culture, a mutant derived from this strain produced the acid at about 35 % yield on the basis of glucose supplied.

Fibrinopeptide A (FPA) level and fibrinogen kinetics in patients with malignant disease.

Abstract: FPA level, fibrinogen turnover rate, and fibrinolytic activity were studied on 18 patients with malignant disease. It was found that the FPA levels were significantly elevated and were correlated with fibrinogen turnover rate (r = 0.74, p less than 0.001) and FDP (r - 0.58, p less than 0.02). Estimated FPA turnover rate was also correlated with fibrinogen turnover rate (r = 0.70, p less than 0.001). These results suggest that fibrinogen catabolism in patients with malignant disease is related with thrombin proteolysis. However, ratios of 1/2 FPA turnover rate to fibrinogen turnover rate suggest that intravascular thrombin proteolysis is not the major determinant of fibrinogen catabolism. It is suspected that extravascular thrombin proteolysis is responsible for the elevation of plasma FPA level which is correlated with acceleration of fibrinogen catabolism.

Threshold behavior of Cu-, Ge-, A g − K − , and A u − L 3 -shell ionization cross sections by electron impact

Abstract: Electron-induced Cu-, Ge-, $\mathrm{A}\mathrm{g}\ensuremath{-}K$ shells, and $\mathrm{A}\mathrm{u}\ensuremath{-}{L}_{3}$-shell ionization cross sections have been obtained from the measurement of $K\ensuremath{\alpha}$ and $L\ensuremath{\alpha}$ x-ray emission cross sections around the threshold energy. $K$- and ${L}_{3}$-shell ionization cross sections have been observed to rise as a function of $\mathrm{ln}\frac{({U}_{i})}{{U}_{i}}$, where ${U}_{i}$ is the ratio of electron impact energy to ionization energy. In the increasing behavior of $\mathrm{A}\mathrm{u}\ensuremath{-}L\ensuremath{\alpha}$ and $\ensuremath{-}L\ensuremath{\beta}$ x-ray emission cross sections with increasing impact energies, the onset of ${L}_{2}$- and ${L}_{1}$-shell ionizations have been observed at ${L}_{2}$- and ${L}_{1}$-shell ionization energies. Absolute values of Cu-, Ge-, $\mathrm{A}\mathrm{g}\ensuremath{-}K$-shell ionization cross sections are well reproduced by the empirical formula of Green and Cosslett down to the vicinity of threshold energy.

Nucleotide sequences of mouse genomic loci including a gene or pseudogene for U6 (4.8S) nuclear RNA

Abstract: We have isolated four clones which hybridize with U6 (48S) nuclear RNA, a mammalian small nuclear RNA(nRNA), from DNA of BALB/C mouse liver Their restriction maps are totally different from each other, indicating that they derived from different loci in the mouse genome The nucleotide sequences around the hybridizing region in the three clones have been determined One clone gives a gene that is co-linear with the U6 RNA There is a sequence TATAAAT beginning 31 nucleotides upstream of the gene, which may suggest that the U6 RNA is transcribed by RNA polymerase II The other two clones contain a pseudogene for the U6 RNA which has 7 or 9 nucleotide changes from the RNA The pseudogenes are surrounded by radically different sequences from those surrounding the gene, and they are closely linked to a pseudogene for another snRNA, 45S-I RNA, or a part of highly repetitive an interspersed sequence B1

Mineral/groundmass partition coefficients for nepheline, melilite, clinopyroxene and perovskite in melilitenepheline basalt, Nyiragongo, Zaire.

Abstract: Four new partition coefficient versus ionic radius diagrams have been presented for nepheline-, melilite-, perovskite-, and clinopyroxene-groundmass of a melilite-nepheline basalt, Nyiragongo volcano, Zaire, Africa. The results were discussed on the basis of the “crystal structure control” mechanism.

Odorous Metabolites of a Fungus, Chaetomium globosum KINZE ex FR. Identification of Geosmin, a Musty-smelling Compound

Abstract: Geosmin, an earthy-musty smelling compound, and 2-phenylethanol were detected by gas chromatography and mass spectrometry combined with gas chromatography from the volatile metabolites of Chaetomium globosum KINZE ex FR., a fungus isolated from the soil at Sugadaira, Nagano Prefecture. It was suggested that fungi are partly responsible for the unpleasant earthy-musty odor and taste in public water supplies.

Recording tapes using iron nitride fine powder

Abstract: Magnetic recording pigment of Fe 4 N particles was prepared by nitrogenizing acicular metal iron powder. The treatment to obtain stoichiometric Fe 4 N was carried out at 400°C for 3 hours in NH 3 -H 2 (3:1) mixed gas. The saturation magnetization and coercive force were 120 emu/g and 700 Oe respectively. The Curie point of the powder coincided well with that of bulk material. Test tapes were prepared with this Fe 4 N powder. The remanent magnetic flux density (Br) of the tape was 2200 G and the coercive force was 670 Oe. From test immersion in saline solution, it is confirmed that the chemical stability of the Fe 4 N tape is superior to the Fe 4 N tape is superior to the metal tape.

Stimulation of Actomyosin Mg2+-ATPase Activity by a Brain Microtubule-Associated Protein Fraction--High-Molecular Weight Actin-Binding Protein Is the Stimulating Factor

Abstract: Actomyosin Mg2+-ATPase activity was stimulated by a brain microtubule-associated protein (MAP) fraction. The stimulating activity of the MAP fraction was abolished by boiling and trypsin treatment, suggesting the presence of a protein factor. The factor stimulated actomyosin Mg2+-ATPase activity stoichiometrically by about four times in the optimum conditions (50--75 mM KCl, pH 6.6). The stimulating factor was coprecipitable with actomyosin and was found to be a pair of high-molecular-weight polypeptides (mol wts, 240,000 and 235,000). The polypeptides were not associated with microtubules or myosin, but with fibrous actin. In column chromatographies used for purifying the stimulating factor, the amount of polypeptides coincided with the stimulating activity. Increases in both specific activity and the amount of the paired polypeptides were nearly parallel in the process of the purification. A purified fraction (65% pure with respect to the paired polypeptides) showed a 56-fold increase of the specific stimulating activity as compared with the initial brain supernatant. The two peptides were similar but not identical with filamin and spectrin in terms of electrophoretic mobility. Hence, the pair of polypeptides was identified as an actin-binding protein newly found in brain.

Handling summary information in a database: derivability

Abstract: "Summary data" is a representation of "groups of facts." Statistics are a typical example of summary data, which is often a major component of databases that deal with huge domains, such as objects in a whole country or events that occurred over a long time range. Although any summary can be reproduced from the corresponding originals, these are often unavailable and the required data may or may not be derivable from the given summary data. A schema of summary data is defined as a relationship between classifications of object types and domains for attributes. Reclassification rules are introduced as semantic relations among classifications. Set theoretical lemmata provide an inference mechanism that judges derivability of required summary data from collected summary data, and derives the former, if it is derivable, from the latter. It is also shown how this inference mechanism improves a summary database in usability and logical data independence. Discussions are made with examples in the statistical field.