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Search Results: 1 - 10 of 2782 matches for " Kunihiko Yoshida "
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Placenta previa and percreta with massive genital bleeding in the first trimester of pregnancy: A case report  [PDF]
Masayuki Yamaguchi, Kunihiko Yoshida, Toru Takano, Takayuki Enomoto, Koichi Takakuwa
Open Journal of Obstetrics and Gynecology (OJOG) , 2013, DOI: 10.4236/ojog.2013.39127
Abstract:

A 40-year-old woman with a history of cesarean section and 3 episodes of uterine curettage for spontaneous or induced abortion presented with massive genital hemorrhage in the ninth week of gestation; she was treated with red cell concentrate and fresh frozen plasma transfusion. She was admitted to our hospital at the 11th week of gestation for continuous genital hemorrhage and cervical shortening (20 mm). Ultrasonography revealed placenta previa totalis. A lowlying gestational sac in early pregnancy, vascular lacunae, and an obscured retroplacental sonolucent zone indicated placenta percreta; magnetic resonance imaging showed similar findings. Owing to placenta percreta, uterus preservation was considered impossible. Elective cesarean section followed by total hysterectomy was performed at the 37th week of gestation, with bilateral internal iliac artery balloon catheter occlusion for reducing blood loss. The perioperative blood loss was 2,835 mL, for which the patient received blood transfusion. The postoperative course was uncomplicated.

Ubiquitous expression of Sry induces embryonic lethality related to suppression of Tie2/Tek expression  [PDF]
Kazuhisa Yoshida, Masanori Ito, Kou Yokouchi, Kiyoshi Kano, Kunihiko Naito, Hideaki Tojo
Advances in Bioscience and Biotechnology (ABB) , 2010, DOI: 10.4236/abb.2010.15058
Abstract: Sry (sex-determining region on the Y chromosome) is a mammalian sex-determining gene on the Y chromosome. In mice, the transient expression of Sry in supporting cell precursor cells between 10.5 and 12.5 days post-coitus (dpc) triggers the differentiation of Sertoli cells from granulosa cells. The importance of the strict regulation of Sry expression remains unknown. Thus, we attempted to produce a Sry ubiquitous-expressing transgenic (Tg) mouse in which foreign Sry is driven by the CAG (cytomegalovirus immediate-early enhancer, chicken beta-actin promoter, and the fusion intron of chicken beta-actin and rabbit beta-globin)-Sry gene for ubiquitous expressing Sry. A low rate (2/127) of Tg pups was observed, whereas the rate of early-stage transgenic embryos before birth was 19.2% (5/26). The Sry ubiquitous-expressing embryos showed abnormal development. The results suggest that ubiquitous expression of Sry exerts a negative effect on embryonic development. One of the two adult Tg mice showed low levels of Sry expression. The other Tg mouse showed high Sry transgene expression, but was mosaic for the transgene. Developmental analysis of transgenic F1 embryos produced from the mosaic Tg mouse revealed that ubiquitous expression of Sry had a lethal effect on embryonic development around 12.5 dpc. The histological data indicated that ubiquitous expression of Sry induced abnormal cardiovascular development, resulting in embryonic death. Enhanced expression of Sry suppressed endogenous Tie2/Tek (tyrosine kinase with Ig and EGF homology domains 2/tunica interna endothelial cell kinase) expression in Sry-transfected primary cultured cells from wild type embryonic hearts. The results indicate that the tissue-specific and stage-specific expression of Sry is essential for normal embryogenesis.
Oocyte Cryopreservation before Tumorectomy in Gorlin-Goltz Syndrome with Recurrent Ovarian Fibroma: A Case Report  [PDF]
Makoto Chihara, Atsushi Fujimoto, Kanna Ogi, Tatsuya Ishiguro, Kunihiko Yoshida, Masayuki Sekine, Koich Takakuwa, Hiroki Fujikawa, Yutaka Shimomura, Takayuki Enomoto
Open Journal of Obstetrics and Gynecology (OJOG) , 2018, DOI: 10.4236/ojog.2018.810087
Abstract: Background: Gorlin-Goltz syndrome is a very rare syndrome that reportedly occurs in 1 of 235,800 people in Japan. The proportion of women with Gorlin-Goltz syndrome complicated with an ovarian fibroma ranges from 12.5% to 17.0%. Some surgical cases of Gorlin-Goltz syndrome with an ovarian tumor have been reported. However, no studies have mentioned subsequent fertility preservation by using oocyte cryopreservation process. Case: In this case report, the patient with Gorlin-Goltz syndrome underwent laparotomy for bilateral ovarian fibrothecoma at 15 years of age. At 20 years of age, a recurrent ovarian tumor was detected in the remaining ovary. During the follow-up, we detected an increase in its size. As tumor torsion requiring left salpingo-oophorectomy was possible, tumorectomy was considered. However, her anti-Müllerian hormone level was low. As she was at risk for premature ovarian failure after tumorectomy, we planned to cryopreserve her oocytes to preserve her fertility before tumorectomy. Outcome: When the patient underwent surgery, the diameter of her left ovarian tumor was found to have increased to 56 mm. Egg collection was performed twice, and two oocytes were cryopreserved. Subsequently, she underwent tumorectomy of the left ovarian tumor. No recurrence has been observed. Conclusion: If a recurrent ovarian tumor is detected in patients with Gorlin-Goltz syndrome and a low anti-Müllerian hormone level, cryopreservation of oocytes before tumorectomy may be effective for preserving their fertility.
Verification of Real-Time Pricing Systems Based on Probabilistic Boolean Networks  [PDF]
Koichi Kobayashi, Kunihiko Hiraishi
Applied Mathematics (AM) , 2016, DOI: 10.4236/am.2016.715146
Abstract: In this paper, verification of real-time pricing systems of electricity is considered using a probabilistic Boolean network (PBN). In real-time pricing systems, electricity conservation is achieved by manipulating the electricity price at each time. A PBN is widely used as a model of complex systems, and is appropriate as a model of real-time pricing systems. Using the PBN-based model, real-time pricing systems can be quantitatively analyzed. In this paper, we propose a verification method of real-time pricing systems using the PBN-based model and the probabilistic model checker PRISM. First, the PBN-based model is derived. Next, the reachability problem, which is one of the typical verification problems, is formulated, and a solution method is derived. Finally, the effectiveness of the proposed method is presented by a numerical example.
An Empirical Analysis of Communication on Trust Building in Virtual Teams  [PDF]
Makoto Shinnishi, Kunihiko Higa
Journal of Service Science and Management (JSSM) , 2018, DOI: 10.4236/jssm.2018.112020
Abstract: This research aims to analyze the communication on trust building in virtual teams. Ten teams consisting of three workers (an editor, a designer, and a coder) were asked to create a sample web page in one week. All workers were in remote environment and a text-only communication tool was provided to all teams. In addition, five teams could use a non-text communication tool through which one can see other member’s situation with a web camera image and a short text message. All communication logs were collected and classified into three types: formal communication, informal communication, and awareness communication. All participated workers answered the questionnaire about trust before and after the task was completed. The analysis results based on the questionnaire and communication log data are discussed at the end. The result shows the use of non-text communication tool did not affect trust building; however, amount of awareness communication affected trust building. Log-in to the communication system at the same time also affected trust building. The findings of this study showed the tendency of awareness communication helping team building trust in the remote environment.
Evolution of Robustness to Noise and Mutation in Gene Expression Dynamics
Kunihiko Kaneko
PLOS ONE , 2007, DOI: 10.1371/journal.pone.0000434
Abstract: Phenotype of biological systems needs to be robust against mutation in order to sustain themselves between generations. On the other hand, phenotype of an individual also needs to be robust against fluctuations of both internal and external origins that are encountered during growth and development. Is there a relationship between these two types of robustness, one during a single generation and the other during evolution? Could stochasticity in gene expression have any relevance to the evolution of these types of robustness? Robustness can be defined by the sharpness of the distribution of phenotype; the variance of phenotype distribution due to genetic variation gives a measure of ‘genetic robustness’, while that of isogenic individuals gives a measure of ‘developmental robustness’. Through simulations of a simple stochastic gene expression network that undergoes mutation and selection, we show that in order for the network to acquire both types of robustness, the phenotypic variance induced by mutations must be smaller than that observed in an isogenic population. As the latter originates from noise in gene expression, this signifies that the genetic robustness evolves only when the noise strength in gene expression is larger than some threshold. In such a case, the two variances decrease throughout the evolutionary time course, indicating increase in robustness. The results reveal how noise that cells encounter during growth and development shapes networks' robustness to stochasticity in gene expression, which in turn shapes networks' robustness to mutation. The necessary condition for evolution of robustness, as well as the relationship between genetic and developmental robustness, is derived quantitatively through the variance of phenotypic fluctuations, which are directly measurable experimentally.
Proportionality between variances in gene expression induced by noise and mutation: consequence of evolutionary robustness
Kunihiko Kaneko
BMC Evolutionary Biology , 2011, DOI: 10.1186/1471-2148-11-27
Abstract: Using numerical models simulating the evolutionary changes in the gene regulation network required to achieve a particular expression pattern, we first confirmed that gene expression dynamics robust to mutation evolved in the presence of a sufficient level of transcriptional noise. Under such conditions, the two types of variances in the gene expression levels, i.e. those due to mutations to the gene regulation network and those due to noise in gene expression dynamics were found to be proportional over a number of genes. The fraction of such genes with a common proportionality coefficient increased with an increase in the robustness of the evolved network. This proportionality was generally confirmed, also under the presence of environmental fluctuations and sexual recombination in diploids, and was explained from an evolutionary robustness hypothesis, in which an evolved robust system suppresses the so-called error catastrophe - the destabilization of the single-peaked distribution in gene expression levels. Experimental evidences for the proportionality of the variances over genes are also discussed.The proportionality between the genetic and epigenetic variances of phenotypes implies the correlation between the robustness (or plasticity) against genetic changes and against noise in development, and also suggests that phenotypic traits that are more variable epigenetically have a higher evolutionary potential.Plasticity and robustness are basic concepts in evolutionary and developmental biology. Plasticity refers to the changeability of phenotypes in response to external environmental perturbations. Indeed many important concepts in biology are concerned with the changeability in the system. This changeability depends on each phenotype: some phenotypes are more variable than others. How is such degree of changeability characterized quantitatively?On the other hand, robustness is another basic concept in evolutionary and developmental biology. Here, phenotypic rob
D_{s0}^+(2317) as an Iso-triplet Four-quark Meson and Production of Its Neutral and Doubly Charged Partners
Terasaki, Kunihiko
High Energy Physics - Phenomenology , 2007, DOI: 10.1143/PTPS.168.211
Abstract: By studying the decays D_{s0}^+(2317) --> D_s^+ pi^0 and D_s^{*+} gamma, It is shown that its assignment to the I_3=0 component of iso-triplet scalar four-quark mesons is favored. Productions of its neutral and doubly charged partners are also studied. As the result, it is concluded that they could be observed in B decays. Their iso-singlet partner might have been observed in the radiative channels of B decays by the BELLE Collaboration.
A new tetra-quark interpretation of X(3872)
Terasaki, Kunihiko
High Energy Physics - Phenomenology , 2007,
Abstract: A new tetra-quark interpretation of X(3872) is presented. In this model, X(3872) consists of two degenerate tetra-quark mesons, {[cn](cbar nbar) +- (cn)[cbar nbar]}_{I=0}, and, therefore, it is naturally understood that X(3872) decays into two different eigenstates of G-parity.
Decay Property of Axial-Vector Tetra-Quark Mesons
Terasaki, Kunihiko
High Energy Physics - Phenomenology , 2013,
Abstract: Decay property of hidden-charm and exotic axial-vector tetra-quark mesons is studied. It is seen that estimated width of hidden-charm iso-triplet partners of X(3872) with an opposite charge-conjugation property as axial-vector tetra-quark mesons, although still crude, is compatible with the measured ones of recently observed Z_c(3900). It is pointed out that an indication of eta-pi^0 peak around 3.2 GeV observed in gamma-gamma collisions gives a clue to select a realistic model of multi-quark mesons.
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