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41.
Takayoshi Yoshida Koji Yamamoto Masao Udo 《European journal of applied physiology and occupational physiology》1993,66(2):155-160
The purpose of the present study was to assess the relationship between the rapidity of increased gas exchange (i.e. oxygen uptake
) and increased cardiac output (
) during the transient phase following the onset of exercise. Five healthy male subjects performed multiple rest-exercise or light exercise (25 W)-exercise transitions on an electrically braked ergometer at exercise intensities of 50, 75, or 100 W for 6 min, respectively. Each transition was performed at least eight times for each load in random order. The
was obtained by a breath-by-breath method, and
was measured by an impedance method during normal breathing, using an ensemble average. On transitions from rest to exercise,
rapidly increased during phase I with time constants of 6.8–7.3 s. The
also showed a similar rapid increment with time constants of 6.0–6.8 s with an apparent increase in stroke volume (SV). In this phase I,
increased to about 29.7%–34.1% of the steady-state value and
increased to about 58.3%–87.0%. Thereafter, some 20 s after the onset of exercise a mono-exponential increase to steady-state occurred both in
and
with time constants of 26.7–32.3 and 23.7–34.4 s, respectively. The insignificant difference between
and
time constants in phase I and the abrupt increase in both
and SV at the onset of exercise from rest provided further evidence for a cardiodynamic contribution to
following the onset of exercise from rest. 相似文献
42.
Toshitsugu Nakamura Masao Hotchi 《Virchows Archiv. B, Cell pathology including molecular pathology》1993,63(1):11-16
DNA strand breaks (nicks) in non-parenchymal cells (NPCs) in CCl4-induced acute or chronic liver injury in rats were detected using an in situ nick translation method; their dynamic changes
were analysed in relation to the proliferation pattern of hepatocytes and NPCs, as revealed by bromodeoxyuridine (BrdU)-up-take.
In acute injury, hepatocyte proliferation started before centrilobular necrosis had occurred, whereas BrdU-labeled sinusoidal
NPCs markedly increased only after centrilobular necrosis was apparent. DNA breakages in NPCs paralleled the proliferation
pattern of these cells, suggesting that nicks are physiological, and reflect proliferation and activated gene expression.
In chronic injury, liver cirrhosis developed after 9 weeks, but BrdU-labeling of hepatocytes was almost the same level as
that in untreated liver. The number of BrdU-labeled NPCs showed only a slight increase, while those with DNA breakages were
much more frequent in the cirrhotic stage, suggesting a significant role for NPCs in the fibrotic process. These results indicate
that DNA strand breaks in NPCs act as a marker for activation states such as proliferation, differentiation and/or activated
gene expression. 相似文献
43.
Watanabe Masao; Nou Ill Sup; Takayama Seiji; Yamakawa Seiyei; Isogai Akira; Suzuki Akinori; Takeuchi Takuji; Hinata Kokichi 《Plant & cell physiology》1992,33(4):343-351
The stigma of Brassica species contain NS-glycoproteins thatexhibit a high degree of structural homology to the S-glycoproteinsof self-incompatibility. Inheritance of and variations in theNS-glycoprotein were studied with reference to self-incompatibility.The detection of NS-glycoproteins was performed by cross-reactionwith an antiserum raised against a purified NS-glycoprotein.In B. campestris, four isoforms of the NS-glycoprotein weredifferentiated by their pI values, but their molecular weightswere identical to one another. The genes for these isoformsof NS-glycoprotein were controlled by alleles at a single locus,tentatively named the NS allele, which was independent of Salleles at both the protein and the DNA level. Segregation ofF2 plants with respect to the self-incompatibility behaviorof pollen tubes can be explained by the S allele model, butit appears not to be affected by the NS alleles. NS-glycoproteinswere found in all 21 species of Brassica and its allies examinedto date. The pI values of these glycoproteins varied among differentspecies. In addition to the isoforms of the NS alleles, maturestigmas contained other groups of proteins that reacted weaklywith the antiserum against the NS-glycoprotein. (Received July 30, 1991; Accepted February 21, 1992) 相似文献
44.
Masao Suzuki Chizuru Tsuruoka Tatsuaki Kanai Takeshi Kato Fumio Yatagai Masami Watanabe 《Biological Sciences in Space》2003,17(4):302-306
We investigated the difference in cell-killing effect and mutation induction between carbon- and neon-ion beams in normal human cells. Carbon- and neon-ion beams were accelerated by the Riken Ring Cyclotron (RRC) at the Institute of Physical and Chemical Research in Japan. Cell-killing effect was measured as the reproductive cell death using the colony formation assay. Mutation induction at the HPRT locus was detected to measure 6-thioguanine-resistant clones. The mutation spectrum of the deletion pattern of exons of induced mutants was analyzed using the multiplex polymerase chain reaction (PCR). Cell-killing effect was almost the same between carbon- and neon-ion beams with similar linear energy transfer (LET) values, while there observed a large difference in mutation frequency. Furthermore, in the case of neon-ion beams 60% of mutants showed total deletions and 35-40% showed partial deletions, while 95-100% of carbon-ion induced mutants showed total deletions. The results suggest that different ion species may cause qualitative and quantitative difference in mutation induction even if the LET values are similar. 相似文献
45.
Hiroyasu Kitashiba Takayoshi Iwai Kinya Toriyama Masao Watanabe Kokichi Hinata 《Sexual plant reproduction》1996,9(3):186-188
The vegetative-to-floral transition ofBrassica campestris cv. Osome was induced by vernalization. Poly(A)+RNA was isolated from the transition shoot apex after 6 weeks of vernalization, the floral apex after 12 weeks of vernalization and the expanded leaves just before vernalization, and cDNAs were synthesized. These cDNAs were used for subtraction and differential screening to select cDNA preferentially present in the transition and floral apices. Nucleotide sequences of the resulting 14 cDNA clones were determined, and northern blot analysis was carried out on six cDNAs. Two cDNA clones which did not show significant similarity to known genes were shown to be preferentially expressed in the floral apex. 相似文献
46.
Tomomi Hidaka Masao Goda Tomohisa Kuzuyama Naomi Takei Makoto Hidaka Haruo Seto 《Molecular & general genetics : MGG》1995,249(3):274-280
The biosynthetic pathway for production of the antibiotic fosfomycin by Streptomyces wedmorensis consists of four steps including the formation of a C-P bond and an epoxide. Fosfomycin production genes were cloned from genomic DNA using S. wedmorensis mutants blocked at different steps of the biosynthetic pathway. Four genes corresponding to each of the biosynthetic steps were found to be clustered in a DNA fragment of about 5 kb. Nucleotide sequencing of a large fragment revealed the presence of ten open reading frames, including the four biosynthetic genes and six genes with unknown functions. 相似文献
47.
In vitro 5-day cultures of naive spleen cells with viable Listeria monocytogenes (VLM), but not heat-killed L. monocytogenes, induced CD4+ T cells that produced IFN-γ upon secondary antigen stimulation. The VLM-induced Listeria-specific T cells produced IFN-γ but lacked expression of IL-2 and IL-4. To study the role of IFN-γ in the induction of the IFN-γ-producing T cells, we added anti-IFN-γ mAb to the primary culture and analyzed IFN-γ production upon secondary antigen stimulation. Addition of anti-IFN-γ mAb to the culture suppressed generation of IFN-γ-producing CD4+ T cells, suggesting that IFN-γ is important in the induction of IFN-γ-producing CD4+ T cells. Furthermore, our results showed that depletion of NK cells from spleen cells by anti-asialo GM1 antibody plus complement before culture enhanced induction of IFN-γ-producing CD4+ T cells. Although NK cells are known to produce IFN-γ, the results indicate that NK cell-derived IFN-γ may not be important in induction of the Listeria-specific IFN-γ-producing CD4+ T cells in the culture system. In addition, we demonstrated that IFN-γ expression was high in CD4+ T cells from cultures of spleen cells with VLM at the primary culture level. These results suggest that IFN-γ derived from T cells may enhance production of IFN-γ by CD4+ T cells, while NK cells rather suppress the induction of IFN-γ-producing CD4+ T cells. 相似文献
48.
In Japan, the green seaweed Monostroma is an important source of humanfood. Monostroma nitidum Wittrock (Japanese name: hitoegusa)
is cultivated in brackish waters and estuaries of central to southern Japan. The green seaweed Monostroma grows in the brackish
water area in the upper part of the intertidal zone in the warm waters. Artificial seed culture began with the collection
of many gametes in April. The resultant zygotes were allowed to adhere to plastic settlement boards (20 cm long and 10 cm
wide). The zygoteboards were then cultured in tanks (1 ×2 ×0.5 m) with fertiliser in a controlled growth room (10–87 μmol
photon m-2s-1). The cultivated zygotes on the board in the indoor tanks gradually increased in size from 10 to 40 μm in diameter during
May to early August. Zygote growth became slowed at the end of August. The zygotesmatured in early September, and the plates
were transferred into culture tanks in a dark room for dark treatment. Maturation of the zygote was promoted by providing
dark conditions for two weeks. The production of a concentrated zoospore solution from the mature blades was achieved by adding
fresh water at temperature 2–3 °C above that of the seeding vats. Zoospores were released in large numbers when exposed to
strong irradiance of 100 μmol photon m-2 s-1 for 30 min. The zygotes produced flat unicellular fronds at the germling stage. The technology of artificial seed culture
and zoospore release from the zygotes is based mainly on these experiments.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
49.
Staphylococcus aureus, which usually forms grape-like clusters, has the ability to form regularly arranged cell packets. These regular cell packets are formed when the activity of its separation enzyme(s) is lost either by treatment with detergents, such as sodium dodecyl sulfate or Trition X-100, or by mutation of the cells. These cell packets consisted of 8 to 64 spherical cells that have a three-dimensional arrangement. Some irregularity in the arragement of cells in packets, however, can be observed by scanning electron microscopy. It is concluded that S. aureus fundametally divides along three definitely oriented planes that are located at right angles to each other. After cell division, the cells usually become translocated due to the action of a separation enzyme(s) to form grape-like clusters. 相似文献
50.
Yoshihide Yamasaki Osamu Shimamura Akira Kizu Masao Nakagawa Hamao Ijichi 《Life sciences》1982,31(5):471-478
The formaldehyde method was used to examine the interaction of PGE1 with morphine, β-endorphin and Met-enkephalin on rat mast cells by their effects on IgE-mediated 14C-serotonin release. PGE1 (2×10?8?2×10?5 M) caused a dose-related inhibition of the mediator release 1 min after an antigen challenge, and morphine (3×10?7?3×10?5 M) reversed this PGE1 effect dose-dependently and stereospecifically; naloxone (2×10?4 M) antagonized this action of morphine. β-Endorphin (3×10?7?10?5 M) and Met-enkephalin (3×10?6?10?4 M) mimicked this morphine action dose-dependently and were antagonized by naloxone (2×10?4 M). These results suggest that morphine and endorphins modulate immunological mediator release from rat mast cells through opioid receptors. 相似文献