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3,060
result(s) for
"Nakahara, T"
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Rapid vascular regrowth in tumors after reversal of VEGF inhibition
by
O'Brien, S.
,
Norberg, S. M.
,
Sennino, B.
in
Actins - metabolism
,
Angiogenesis Inhibitors - pharmacology
,
Angiogenesis Inhibitors - therapeutic use
2006
Inhibitors of VEGF signaling can block angiogenesis and reduce tumor vascularity, but little is known about the reversibility of these changes after treatment ends. In the present study, regrowth of blood vessels in spontaneous RIP-Tag2 tumors and implanted Lewis lung carcinomas in mice was assessed after inhibition of VEGF receptor signaling by AG-013736 or AG-028262 for 7 days. Both agents caused loss of 50%-60% of tumor vasculature. Empty sleeves of basement membrane were left behind. Pericytes also survived but had less alpha-SMA immunoreactivity. One day after drug withdrawal, endothelial sprouts grew into empty sleeves of basement membrane. Vessel patency and connection to the bloodstream followed close behind. By 7 days, tumors were fully revascularized, and the pericyte phenotype returned to baseline. Importantly, the regrown vasculature regressed as much during a second treatment as it did in the first. Inhibition of MMPs or targeting of type IV collagen cryptic sites by antibody HUIV26 did not eliminate the sleeves or slow revascularization. These results suggest that empty sleeves of basement membrane and accompanying pericytes provide a scaffold for rapid revascularization of tumors after removal of anti-VEGF therapy and highlight their importance as potential targets in cancer therapy.
Journal Article
Development of micro mechanical device having two-dimensional array of micro chambers for cell stretching
2018
This paper presents a novel cell stretching micro device having two-dimensional array of micro chambers. It enables an in situ time-lapse observation of stretched cell by using an optical microscope with high measurement efficiency. The presented device consists of a cell culture dish and the array of micro chambers made of silicone elastomer and extension structures made of photocurable resin, and is fabricated with MEMS technology. The fabrication process of the thin micro chamber array combines photoresist mold and lift-off process based on conventional photolithography. The fabricated device has 134 micro chambers in 5μm or less thickness. It was demonstrated that the fabricated micro device could be used to make in-situ time-lapse observation of cell responses to stretching under optical microscopy. In addition, the influence of the chamber thickness to the quality of the microscope image observed was evaluated. It is confirmed that the proposed device having two-dimensional array of the thin micro chambers makes it possible to observe cell response for stretch stimuli with high quality and efficiency.
Journal Article
Transitions to slow or fast diffusions provide a general property for in-phase or anti-phase polarity in a cell
2020
Cell polarity is an important cellular process that cells use for various cellular functions such as asymmetric division, cell migration, and directionality determination. In asymmetric cell division, a mother cell creates multiple polarities of various proteins simultaneously within her membrane and cytosol to generate two different daughter cells. The formation of multiple polarities in asymmetric cell division has been found to be controlled via the regulatory system by upstream polarity of the membrane to downstream polarity of the cytosol, which is involved in not only polarity establishment but also polarity positioning. However, the mechanism for polarity positioning remains unclear. In this study, we found a general mechanism and mathematical structure for the multiple streams of polarities to determine their relative position via conceptional models based on the biological example of the asymmetric cell division process of C. elegans embryo. Using conceptional modeling and model reductions, we show that the positional relation of polarities is determined by a contrasting role of regulation by upstream polarity proteins on the transition process of diffusion dynamics of downstream proteins. We analytically prove that our findings hold under the general mathematical conditions, suggesting that the mechanism of relative position between upstream and downstream dynamics could be understood without depending on a specific type of bio-chemical reaction, and it could be the universal mechanism in multiple streams of polarity dynamics of the cell.
Journal Article
Correction to: Development of micro mechanical device having two-dimensional array of micro chambers for cell stretching
2018
The original article has been corrected. Instances of the character \"μ\" should be replaced by the term \"micro\".
Journal Article
Lenalidomide induces cell death in an MDS-derived cell line with deletion of chromosome 5q by inhibition of cytokinesis
2010
Myelodysplastic syndromes (MDS) are a group of hematopoietic stem cell disorders characterized by refractory cytopenias and susceptibility to leukemic transformation. On a subset of MDS patients with deletion of the long arm of chromosome5 (del(5q)), lenalidomide exerts hematological and cytogenetic effects, but the underlying pharmacological mechanisms are not fully understood. In this study, we have investigated the
in vitro
effects of lenalidomide on an MDS-derived cell line, MDS-L, which carries del(5q) and complex chromosome abnormalities. We found that the growth of MDS-L cells was specifically suppressed mainly by apoptosis, and in addition, multinucleated cells were frequently formed and finally died out in the presence of lenalidomide. Time-lapse microscopic observation and the DNA ploidy analysis revealed that lenalidomide does not affect DNA synthesis but inhibits cytokinesis of MDS-L cells. The gene expression profile showed decreased expression of M phase-related genes such as non-muscle myosin heavy-chain 10, polo-like kinase 1, aurora kinase B, citron kinase and kinesin family member
20A
(
KIF20A
). Interestingly,
KIF20A
is located at 5q31. These data contribute to the understanding of action mechanisms of lenalidomide on MDS with del(5q) and complex abnormalities.
Journal Article
Optimization of docosahexaenoic acid production by Schizochytrium limacinum SR21
by
Higashihara, T
,
Yokochi, T
,
Honda, D
in
Acid production
,
Arachidonic acid
,
Biological Sciences
1998
Culture conditions of Schizochytrium limacinum SR21 for the purpose of microbial docosahexaenoic acid (DHA) production were investigated. The strain SR21 showed a wide tolerance to salinity; that is, the optimum salinity was between 50% and 200% that of sea water. Monosaccharides (glucose and fructose) and glycerol supported good cell growth and DHA yield. Di-and polysaccharides, oleic acid, and linseed oil gave low DHA yields. A high content of DHA (more than 30% of total fatty acids) was obtained from culture on glucose, fructose, and glycerol, and also the strain had simple polyunsaturated fatty acid profiles. The major polyunsaturated fatty acids other than DHA were n-6 docosapentaenoic acid only, and the contents of icosapentaenoic acid and arachidonic acid were less than 1%. Using corn steep liquor as a nitrogen source, a high total fatty acid content was obtained. The total fatty acid content in the dry cell weight increased as the concentration of the nitrogen source decreased, reached more than 50%. An increase in carbon source concentration led to a high DHA yield. A maximum DHA yield of more than 4 g/l was obtained in both glucose and glycerol media at 9% and 12% respectively. S. limacinum SR21 was thought to be a promising resource for microbial DHA production yielding a good level of productivity as well as a simple polyunsaturated fatty acid profile.
Journal Article
Study about forest management planning by CSR activities: a case study of the Kishiwada Hilly Development District in Japan
2018
The objective of this study was to clarify the method of forest activities of CSR for collaboration between companies and local communities, focusing on the Kishiwada Hilly Development district in Japan. The research method is mesh analysis by GIS, a questionnaire, interviews and a field survey. First, this area was subdivided as divided into 2625 meshes, and each of the meshes was evaluated via the natural conservation importance index and recreational usability index. Second, we examined the zoning estimation method based on spatial characteristics and the difference in human activities. Third, we identified the beliefs and challenges for CSR forest activities by the four companies participating in forest activities in the study area. The result was, first, bamboo forest accounts for 26.2%, such as forests without administrators. Second, suitable forests for recreation totalled 52.3%, occupies a majority of the land. Third, the purpose of participation in corporate forest-making activities varied depending on the departments. A common problem was a lack of knowledge regarding forest management. In conclusion, these findings suggest that the development of forest management plans considering the needs of CSR forest activities and the conditions throughout the region would improve the resilience and the benefits of Satochi-Satoyama.
Journal Article
Marked anti-tumour activity of the combination of YM155, a novel survivin suppressant, and platinum-based drugs
by
Fukuoka, M
,
Kuwata, K
,
Hatashita, E
in
631/154/436/2388
,
692/699/67/1612/1350
,
692/700/565/1436/1437
2010
Background:
Survivin, a member of the inhibitor of apoptosis protein family, is an attractive target for cancer therapy. We have now investigated the effects of the combination of YM155, a novel small-molecule inhibitor of survivin expression, and platinum compounds (cisplatin and carboplatin) on human non-small cell lung cancer (NSCLC) cell lines.
Methods:
The anti-cancer efficacy of YM155 in combination with platinum compounds was evaluated on the basis of cell death and progression of tumour xenografts. Platinum compound-induced DNA damage was evaluated by immunofluorescence analysis of histone
γ
-H2AX.
Results:
Immunofluorescence analysis of histone
γ
-H2AX showed that YM155 delayed the repair of double-strand breaks induced in nuclear DNA by platinum compounds. The combination of YM155 and platinum compounds also induced synergistic increases both in the number of apoptotic cells and in the activity of caspase-3. Finally, combination therapy with YM155 and platinum compounds delayed the growth of NSCLC tumour xenografts in nude mice to an extent greater than that apparent with either treatment modality alone.
Conclusion:
These results suggest that YM155 sensitises tumour cells to platinum compounds both
in vitro
and
in vivo
, and that this effect is likely attributable to the inhibition of DNA repair and consequent enhancement of apoptosis.
Journal Article
A single band does not always represent single bacterial strains in denaturing gradient gel electrophoresis analysis
by
Sekiguchi, Hiroyuki
,
Tomioka, Noriko
,
Nakahara, Tadaatsu
in
Bacteria
,
Bacteriological methods and techniques used in bacteriology
,
Bacteriology
2001
DNA in a denaturing gradient gel electrophoresis (DGGE) band that could not be sequenced after recovery from the gel was cloned into a TA cloning vector and a library was constructed and then 13 clones randomly picked up from the library was sequenced. Although the excised DNA from the DGGE gel showed a single band, the library consisted of several different sequences phylogenetically. This phenomenon was also observed in several other DGGE bands. Therefore, this suggests that a single DGGE band does not always represent a single bacterial strain and a new bias for quantitative analyses based on band intensities has been identified.[PUBLICATION ABSTRACT]
Journal Article
Microbial degradation of polyurethane, polyester polyurethanes and polyether polyurethanes
by
Nakajima-Kambe, T.
,
Onuma, F.
,
Nakahara, T.
in
Amino acid sequence
,
Amino acids
,
Bacteria - genetics
1999
Polyurethane (PUR) is a polymer derived from the condensation of polyisocyanate and polyol and it is widely used as a base material in various industries. PUR, in particular, polyester PUR, is known to be vulnerable to microbial attack. Recently, environmental pollution by plastic wastes has become a serious issue and polyester PUR had attracted attention because of its biodegradability. There are many reports on the degradation of polyester PUR by microorganisms, especially by fungi. Microbial degradation of polyester PUR is thought to be mainly due to the hydrolysis of ester bonds by esterases. Recently, polyester-PUR-degrading enzymes have been purified and their characteristics reported. Among them, a solid-polyester-PUR-degrading enzyme (PUR esterase) derived from Comamonas acidovorans TB-35 had unique characteristics. This enzyme has a hydrophobic PUR-surface-binding domain and a catalytic domain, and the surface-binding domain was considered as being essential for PUR degradation. This hydrophobic surface-binding domain is also observed in other solid-polyester-degrading enzymes such as poly(hydroxyalkanoate) (PHA) depolymerases. There was no significant homology between the amino acid sequence of PUR esterase and that of PHA depolymerases, except in the hydrophobic surface-binding region. Thus, PUR esterase and PHA depolymerase are probably different in terms of their evolutionary origin and it is possible that PUR esterases come to be classified as a new solid-polyester-degrading enzyme family.
Journal Article