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Search Results: 1 - 10 of 2134 matches for " Kazuhiko Hayashi "
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Aortic Dissection Complicated with Fatal Cerebral Infarction: Case Report and Review of Literatures  [PDF]
Kentaro Hayashi, Nobutaka Horie, Kazuhiko Suyama, Izumi Nagata
Open Journal of Modern Neurosurgery (OJMN) , 2012, DOI: 10.4236/ojmn.2012.22005
Abstract: Acute aortic dissection is a life-threatening condition requiring immediate assessment and therapy. Rarely, aortic dis-section involves carotid arteries and manifest cerebral infarction. Here, we report a case of aortic dissection complicated with fatal cerebral infarction. A 83-year-old man, who suddenly suffered consciousness disturbance and right hemiparesis, was transferred to our hospital for the treatment of stroke. Magnetic resonance image revealed massive cerebral infarction in the left cerebral hemisphere as well as occlusion of the left internal carotid artery. Duplex ultrasonography demonstrated arterial dissection in the bilateral carotid arteries and the blood flow was compromised especially in the left side. Aortic dissection was confirmed by the contrast enhanced computed tomography. He was treated conservatively and died of cerebral hernia three days after the onset. In conclusion, aortic dissection may involve carotid artery and results in cerebral infarction. Ultrasound screening can aid timely diagnosis of aortic dissection and further management.
Contribution of CD3 ε Epitope and Oxidative Type of Copper-Zinc Superoxide Dismutase to the Degeneration Processes of Cerebellar Purkinje Cells in Patients with Multiple System Atrophy-Cerebellar Type (MSA-C: Olivopontocerebellar Atrophy, OPCA): An Immunohistochemical Study  [PDF]
Masako Kato, Shinsuke Kato, Kiyota Kato, Kazuhiko Hayashi
World Journal of Neuroscience (WJNS) , 2016, DOI: 10.4236/wjns.2016.64034
Abstract: Objective: This study aimed to investigate the contribution of CD3 epsilon (ε) epitope and oxidative type of copper-zinc superoxide dismutase to the degeneration processes of cerebellar Purkinje cells in patients with Multiple System Atrophy-Cerebellar type (MSA-C). Methods: This retrospective study was carried out on autopsy specimens of 17 patients with sporadic MSA-C and 10 normal individuals. Paraffin sections of autopsied cerebella and pontes were immunostained with polyclonal antibodies against CD3 ε epitope and oxidative modification to cysteine sulfonic acid of cys111 in human copper-zinc superoxide dismutase (Ox-SOD1). With respect to the areas of CD3-ε-epitope expression, the immunohistochemical study and the quantitative statistical analysis between the areas of CD3-ε-epitope expression in the surviving Purkinje cells of MSA-C patients and their disease duration were performed. Results: The cell bodies and dendritic arborization including primary, secondary, and tertiary dendrites of normal Purkinje cells were intensely immunostained by the antibody against CD3 ε epitope. Both the immunohistochemical study and the quantitative statistical analysis revealed that the areas positive for CD3 ε epitope disappeared in the order from tertiary dendrites, secondary dendrites, primary dendrites toward the cell bodies, along with the disease progression. In addition, Glial Cytoplasmic Inclusions (GCIs) and Neuronal Cytoplasmic Inclusions (NCIs) were strongly positive for CD3 ε epitope. The surviving Purkinje cells in MSA-C showed immunostaining by the anti-Ox-SOD1 antibody, although normal Purkinje cells did not. Conclusion: Based on the oxidative stress that the surviving Purkinje cells
A Fungal Metabolite Asperparaline A Strongly and Selectively Blocks Insect Nicotinic Acetylcholine Receptors: The First Report on the Mode of Action
Koichi Hirata,Saori Kataoka,Shogo Furutani,Hideo Hayashi,Kazuhiko Matsuda
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0018354
Abstract: Asperparalines produced by Aspergillus japonicus JV-23 induce paralysis in silkworm (Bombyx mori) larvae, but the target underlying insect toxicity remains unknown. In the present study, we have investigated the actions of asperparaline A on ligand-gated ion channels expressed in cultured larval brain neurons of the silkworm using patch-clamp electrophysiology. Bath-application of asperparaline A (10 μM) had no effect on the membrane current, but when delivered for 1 min prior to co-application with 10 μM acetylcholine (ACh), it blocked completely the ACh-induced current that was sensitive to mecamylamine, a nicotinic acetylcholine receptor (nAChR)-selective antaogonist. In contrast, 10 μM asperparaline A was ineffective on the γ-aminobutyric acid- and L-glutamate-induced responses of the Bombyx larval neurons. The fungal alkaloid showed no-use dependency in blocking the ACh-induced response with distinct affinity for the peak and slowly-desensitizing current amplitudes of the response to 10 μM ACh in terms of IC50 values of 20.2 and 39.6 nM, respectively. Asperparaline A (100 nM) reduced the maximum neuron response to ACh with a minimal shift in EC50, suggesting that the alkaloid is non-competitive with ACh. In contrast to showing marked blocking action on the insect nAChRs, it exhibited only a weak blocking action on chicken α3β4, α4β2 and α7 nAChRs expressed in Xenopus laevis oocytes, suggesting a high selectivity for insect over certain vertebrate nAChRs.
A Refutation of the Diagonal Argument  [PDF]
Kazuhiko Kotani
Open Journal of Philosophy (OJPP) , 2016, DOI: 10.4236/ojpp.2016.63027
Abstract: The diagonal argument is a very famous proof, which has influenced many areas of mathematics. However, this paper shows that the diagonal argument cannot be applied to the sequence of potentially infinite number of potentially infinite binary fractions. First, the original form of Cantor’s diagonal argument is introduced. Second, it is demonstrated that any natural number is finite, by a simple mathematical induction. Third, the concept of potential infinity, created by Aristotle, is presented. Typically, the natural numbers are considered potentially infinite. However, although any natural number is finite, there is also no limit to how large a natural number can be. Fourth, the concept of the potentially infinite decimal is introduced. Fifth, it is easily proven that the diagonal argument cannot be applied to the sequence of all n-bit binary fractions in the interval [0,1). Finally, the diagonal argument is shown to be inapplicable to the sequence of the potentially infinite number of potentially infinite binary fractions, which contains all n-bit binary fractions in the interval [0,1) for any n.
Differential Calculus Based on the Double Contradiction  [PDF]
Kazuhiko Kotani
Open Journal of Philosophy (OJPP) , 2016, DOI: 10.4236/ojpp.2016.64039
Abstract: The derivative is a basic concept of differential calculus. However, if we calculate the derivative as change in distance over change in time, the result at any instant is 0/0, which seems meaningless. Hence, Newton and Leibniz used the limit to determine the derivative. Their method is valid in practice, but it is not easy to intuitively accept. Thus, this article describes the novel method of differential calculus based on the double contradiction, which is easier to accept intuitively. Next, the geometrical meaning of the double contradiction is considered as follows. A tangent at a point on a convex curve is iterated. Then, the slope of the tangent at the point is sandwiched by two kinds of lines. The first kind of line crosses the curve at the original point and a point to the right of it. The second kind of line crosses the curve at the original point and a point to the left of it. Then, the double contradiction can be applied, and the slope of the tangent is determined as a single value. Finally, the meaning of this method for the foundation of mathematics is considered. We reflect on Dehaene’s notion that the foundation of mathematics is based on the intuitions, which evolve independently. Hence, there may be gaps between intuitions. In fact, the Ancient Greeks identified inconsistency between arithmetic and geometry. However, Eudoxus developed the theory of proportion, which is equivalent to the Dedekind Cut. This allows the iteration of an irrational number by rational numbers as precisely as desired. Simultaneously, we can define the irrational number by the double contradiction, although its existence is not guaranteed. Further, an area of a curved figure is iterated and defined by rectilinear figures using the double contradiction.
What Is Number?  [PDF]
Kazuhiko Kotani
Open Journal of Philosophy (OJPP) , 2017, DOI: 10.4236/ojpp.2017.72008
Abstract: What is number? This question is difficult to answer. Because the number is one of the most basic concepts, it is difficult to define the natural number with other concepts. Still, this problem is worth trying to answer. Now, everything is digitized and processed on computer. The importance of the number is increasing day by day. Now is time to consider what number is. Throughout the history of humankind, the ancient Greeks considered this question most profoundly. In particular, Plato defined the natural number one. The natural number one is equal, invariable and indivisible. These properties are intuitively acceptable. However, we have never seen or touched the natural number one itself. How can we know it? Socrates said that we know it before birth. This claim is called anamnesis. In this paper, we use a method, in which Socrates’ anamnesis is studied by the contemporary science. From a modern viewpoint, we could take Socrates’ anamnesis to mean that the natural number one is written in our genes. This article considers whether there is a biological entity corresponding to the natural number one. As a result, we find that a life itself is the prototype of the natural number one, and then properties of life make a critical base of DNA similar to the natural number one through natural selection. A life is an integrated and indivisible system, which resists the law of entropy. Furthermore, the basic properties of life enable natural selection, which conserves genetic information despite the law of entropy. The source of the power, which enables life to resist the law of entropy, is the genetic information. In conclusion, a life is a prototype of the natural number one. Furthermore, a life recognizes nature using natural numbers and resists the law of entropy using natural numbers.
Direct Observation of Strand Passage by DNA-Topoisomerase and Its Limited Processivity
Katsunori Yogo, Taisaku Ogawa, Masahito Hayashi, Yoshie Harada, Takayuki Nishizaka, Kazuhiko Kinosita
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0034920
Abstract: Type-II DNA topoisomerases resolve DNA entanglements such as supercoils, knots and catenanes by passing one segment of DNA duplex through a transient enzyme-bridged double-stranded break in another segment. The ATP-dependent passage reaction has previously been demonstrated at the single-molecule level, showing apparent processivity at saturating ATP. Here we directly observed the strand passage by human topoisomerase IIα, after winding a pair of fluorescently stained DNA molecules with optical tweezers for 30 turns into an X-shaped braid. On average 0.51±0.33 μm (11±6 turns) of a braid was unlinked in a burst of reactions taking 8±4 s, the unlinked length being essentially independent of the enzyme concentration between 0.25–37 pM. The time elapsed before the start of processive unlinking decreased with the enzyme concentration, being ~100 s at 3.7 pM. These results are consistent with a scenario where the enzyme binds to one DNA for a period of ~10 s, waiting for multiple diffusional encounters with the other DNA to transport it across the break ~10 times, and then dissociates from the binding site without waiting for the exhaustion of transportable DNA segments.
Amphiregulin and Epiregulin mRNA expression in primary colorectal cancer and corresponding liver metastases
Hidekazu Kuramochi, Go Nakajima, Yuka Kaneko, Ayako Nakamura, Yuji Inoue, Masakazu Yamamoto, Kazuhiko Hayashi
BMC Cancer , 2012, DOI: 10.1186/1471-2407-12-88
Abstract: One hundred twenty colorectal cancer patients with liver metastases (100 with synchronous metastases, 20 with metachronous) were evaluated. No patients had ever received anti-EGFR antibody agents. AREG and EREG mRNA expression from both the primary tumor and liver metastases were measured using real-time RT-PCR. KRAS codon 12, 13 mutation status was analyzed by direct sequencing.Modest, but significant, correlations were observed between primary tumor and corresponding liver metastases in both AREG mRNA expression (Rs = 0.54, p < 0.0001) and EREG mRNA expression (Rs = 0.58, p < 0.0001). AREG and EREG mRNA expression was strongly correlated in both the primary tumor (Rs = 0.81, p < 0.0001) and the liver metastases (Rs = 0.87, p < 0.0001). No significant survival difference was observed between low and high AREG or EREG patients when all 120 patients were analyzed. However, when divided by KRAS status, KRAS wild-type patients with low EREG mRNA levels in the primary site showed significantly better overall survival rates than those with high levels (p = 0.018). In multivariate analysis, low EREG expression was significantly associated with better overall survival (p = 0.006).AREG and EREG expression showed a modest correlation between primary tumor and liver metastases. As EREG mRNA expression was associated with decreased survival, it is appeared to be a useful prognostic marker in KRAS wild-type patients who never received anti-EGFR therapy.Epidermal growth factor receptor (EGFR) is known to be involved in signaling pathways affecting cellular growth, differentiation, and proliferation [1]. To block the activation of this receptor, the anti-EGFR antibody agents Cetuximab and Panitumumab have been developed, and offer promising results for cases of metastatic colorectal cancer (CRC) [2-4]. Recently, several clinical trials demonstrated that somatic mutations in KRAS are associated with a lack of sensitivity to anti-EGFR antibody agents [5-7], suggesting that KRAS is
Management of esophageal stricture after complete circular endoscopic submucosal dissection for superficial esophageal squamous cell carcinoma
Hajime Isomoto, Naoyuki Yamaguchi, Toshiyuki Nakayama, Tomayoshi Hayashi, Hitoshi Nishiyama, Ken Ohnita, Fuminao Takeshima, Saburo Shikuwa, Shigeru Kohno, Kazuhiko Nakao
BMC Gastroenterology , 2011, DOI: 10.1186/1471-230x-11-46
Abstract: Seven patients who underwent wholly circumferential ESD for superficially extended esophageal squamous cell carcinoma were enrolled in this study. In 3 patients, prophylactic endoscopic balloon dilatation (EBD) was started on the third post-ESD day and was performed twice a week for 8 weeks. In 4 patients, oral prednisolone was started with 30 mg daily on the third post-ESD day, tapered gradually (daily 30, 30, 25, 25, 20, 15, 10, 5 mg for 7 days each), and then discontinued at 8 weeks. EBD was used as needed whenever patients complained of dysphagia.En bloc ESD with tumor-free margins was safely achieved in all cases. Patients in the prophylactic EBD group required a mean of 32.7 EBD sessions; the postprocedural stricture was dilated up to 18 mm in diameter in these patients. On the other hand, systemic steroid administration substantially reduced or eliminated the need for EBD. Corticosteroid therapy was not associated with any adverse events. Post-ESD esophageal stricture after complete circular ESD was persistent, requiring multiple EBD sessions.Use of oral prednisolone administration may be an effective treatment strategy for reducing post-ESD esophageal stricture after complete circular ESD.Endoscopic submucosal dissection (ESD) was developed to dissect directly along the submucosal layer for gastric epithelial neoplasia [1,2]. ESD has an advantage over endoscopic mucosal resection (EMR) for removing gastrointestinal tumors en bloc, regardless of their size [1,2]. ESD allows precise histological assessment of the specimens excised in one piece with tumor-free lateral/basal margins, preventing residual disease and local recurrence [2,3].Several studies in advanced institutes showed that ESD was promising for superficial esophageal epithelial neoplasms with nominal risks for nodal or distant metastasis [4,5]. Nevertheless, a substantial risk of procedure-related complications, including potentially life-threatening perforation and postprocedural stenosis, have b
Magnifying Endoscopic Findings Can Predict Clinical Outcome during Long-Term Follow-Up of More Than 12 Months in Patients with Ulcerative Colitis
Hajime Isomoto,Ryohei Uehara,Tomayoshi Hayashi,Junya Shiota,Kayoko Matsushima,Chun Chuan Chen,Fuminao Takeshima,Toshiyuki Nakayama,Kazuhiko Nakao
Gastroenterology Research and Practice , 2013, DOI: 10.1155/2013/671576
Abstract: Background and Aims. To explore the association of magnifying endoscopic (ME) findings with histopathology and relapse in ulcerative colitis (UC). Methods. Forty-six patients with UC underwent ME with narrow band imaging (NBI) and crystal violet staining and were followed for more than 12 months. ME findings with vital staining were classified into ME-A, regular arrangement of round to oval pits; ME-B, irregular arrangement with/without enlarged spaces between even pits; ME-C, irregular pits in size and shape with more irregular arrangement of pits; and ME-D, disrupted or disappeared pits. NBI-guided ME features of microvascular pattern (MVP) were divided into the MVP-regular and MVP-irregular type. Results. There were 5, 24, 10, and 7 cases of ME-A, ME-B, ME-C, and ME-D grade, respectively, while there were 21 and 25 of MVP-regular and MVP-irregular type, respectively. ME classifications were significantly associated with Matts endoscopic grade. ME classifications and MVP types were significantly associated with each pathognomonic microscopic feature of severe mucosal inflammation, crypt abscess, and goblet cell depletion. There were significant differences in the percentages of remission among ME classifications and between MVP types. Conclusion. ME findings can be predictive of relapse in UC and reliable for in vivo histopathological assessment. 1. Introduction Ulcerative colitis (UC) is a chronic inflammatory bowel disorder characterized by diffuse mucosal inflammation of the colorectum with exacerbations and remissions. The diagnosis of UC is obtained by incorporating clinical, laboratory, radiological, endoscopic, and histopathological findings [1]. Assessment of UC activity via conventional colonoscopy is essential to determine the extent and severity of the disease to optimize therapeutic strategy [1]. Higher severity of endoscopic lesions in UC predicts more aggressive clinical courses and increased rates of surgery [2]. Nevertheless, there are discrepancies between colonoscopic and histopathological findings in patients with clinically inactive UC. Even when routine colonoscopy suggests remission with the normal-appearing mucosa, that is, a common, standardized diagnosis of anatomic remission in accordance with the clinical feature, microscopic inflammatory abnormalities may persist and relapse may occur sooner or later. In the clinical setting of inactive UC, therefore, the disease relapse is difficult to be predicted by routine colonoscopy alone [1, 2]. Magnifying endoscopy (ME) with vital staining is useful for diagnosing colorectal
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