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Biomedical subjects

M Maeda

Publications and source records attributed to M Maeda.

At least 19 recordsLinked to original sources
PubMed2006

Radiation-induced gamma-H2AX in mammalian cells irradiated with a synchrotron X-ray microbeam.

In order to study the radiobiological effects from low dose radiation, a cell irradiation system using synchrotron X-ray microbeam has been developed, by which cells can be recognised individually and irradiated one by one with the desired dose of monochromatic X rays. The minimum beam sizes obtained are 2 microm with the focusing optics and 5 microm square with the non-focused beam, and the beam size can be changed easily with a high-precision slit in the case of a non-focused beam. Human fibroblast cells were individually irradiated with this system, and immunostained by gamma-H2AX antibody to visualise the DNA damage. Most of the fluorescent foci were observed in a localised area in cell nuclei, the size of which was almost the same as the beam size.

Cells, Cultured↗
PubMed2006

Lithium inhibits stress-induced changes in tau phosphorylation in the mouse hippocampus.

It has been pointed out that hyperphosphorylation of microtubule-associated protein tau caused by stress might participate in the early stages of Alzheimer's disease pathogenesis. In the present study, we investigated the effects of cold water stress (CWS) on tau phosphorylation in the mouse hippocampus and the effects of GSK-3beta inhibitor, LiCl, on CWS-induced changes in tau phosphorylation levels by immunoblot analyses. CWS exposure caused an increase in tau phosphorylation at the Tau-1 (Ser199/202), AT8 (Ser202/Thr205) and Ser396 sites. CWS-induced changes in tau phosphorylation at the Ser199/202 and Ser396, but not at Ser202/Thr205, were significantly attenuated by LiCl pretreatment. Total tau levels also showed a decided tendency to increase after CWS, which tendency was also countered by LiCl. Finally, we showed that CWS increased the active form of GSK-3beta that was phosphorylated at Tyr216. These results suggest that a CWS-induced increase in phosphorylated tau in the hippocampus is mediated, at least partly, by the activation of GSK-3beta.

Animals↗
PubMed2006

Expression of inappropriate cadherins by epithelial tumor cells promotes endocytosis and degradation of E-cadherin via competition for p120(ctn).

Cadherin cell-cell adhesion proteins play an important role in modulating the behavior of tumor cells. E-cadherin serves as a suppressor of tumor cell invasion, and when tumor cells turn on the expression of a non-epithelial cadherin, they often express less E-cadherin, enhancing the tumorigenic phenotype of the cells. Here, we show that when A431 cells are forced to express R-cadherin, they dramatically downregulate the expression of endogenous E- and P-cadherin. In addition, we show that this downregulation is owing to increased turnover of the endogenous cadherins via clathrin-dependent endocytosis. p120(ctn) binds to the juxtamembrane domain of classical cadherins and has been proposed to regulate cadherin adhesive activity. One way p120(ctn) may accomplish this is to serve as a rheostat to regulate the levels of cadherin. Here, we show that the degradation of E-cadherin in response to expression of R-cadherin is owing to competition for p120(ctn).

Binding, Competitive↗
PubMed2006

Loss of interleukin-2-dependency in HTLV-I-infected T cells on gene silencing of thioredoxin-binding protein-2.

The transition from interleukin-2 (IL-2)-dependent to IL-2-independent growth is considered one of the key steps in the transformation of human T-cell leukemia virus type-I (HTLV-I)-infected T cells. The expression of thioredoxin-binding protein-2 (TBP-2) is lost during the transition of HTLV-I-infected T-cell lines. Here, we analysed the mechanism of loss of TBP-2 expression and the role of TBP-2 in IL-2-dependent growth in the in vitro model to investigate multistep transformation of HTLV-I. CpGs in the TBP-2 gene are methylated in IL-2-independent but not in IL-2-dependent cells. Sequential treatment with 5-aza-2'-deoxycytidine and a histone deacetylase inhibitor augmented histone acetylation and TBP-2 expression, suggesting that loss of TBP-2 expression is due to DNA methylation and histone deacetylation. In IL-2-dependent cells, a basal level of TBP-2 expression was maintained by IL-2 associated with cellular growth, whereas TBP-2 expression was upregulated on deprivation of IL-2 associated with growth suppression. Overexpression of TBP-2 in IL-2-independent cells suppressed the growth and partially restored responsiveness to IL-2. Knockdown of TBP-2 caused the IL-2-dependent cells to show partial growth without IL-2. These results suggested that epigenetic silencing of the TBP-2 gene results in a loss of responsiveness to IL-2, contributing to uncontrolled IL-2-independent growth in HTLV-I-infected T-cell lines.

Acetylation↗
PubMed2006

Reversible splenial lesion with restricted diffusion in a wide spectrum of diseases and conditions.

OBJECTIVE: Reversible lesion in the central area of the splenium of the corpus callosum (SCC) is a unique phenomenon occurring particularly in patients with encephalitis or encephalopathy and in patients receiving antiepileptic drugs (AED). We report MR imaging findings, clinical courses, and outcomes in eight patients with various diseases and conditions. MATERIALS AND METHODS: Eight patients with a reversible SCC lesion with transiently restricted diffusion were reviewed retrospectively. Diseases and conditions that were associated with a reversible lesion included epilepsy receiving AED (n=1), seizure from eclampsia receiving AED (n=1), mild infectious encephalitis (n=2), hypernatremia resulting in osmotic myelinolysis (n=1), and neoplasm (n=3) such as acute lymphocytic leukemia, spinal meningeal melanocytoma, and esophageal cancer. We evaluated MR imaging findings and clinical findings. RESULTS: Seven patients had isolated SCC lesions; one patient with osmotic myelinolysis showed additional parenchymal lesions. The reversible SCC lesion shape was oval (n=6) or extended (n=2). The mean apparent diffusion coefficient value of the splenial lesion was 0.40+/-0.16 x 10-3 mm2/s, ranging from 0.22 to 0.64 x 10-3 mm2/s. In a patient with osmotic myelinolysis, additional white matter lesions, shown as restricted diffusion, were revealed as not reversible on follow-up MR imaging. Neurological courses and outcomes were good in seven patients with isolated SCC lesions, but poor in one with osmotic myelinolysis. CONCLUSION: Reversible SCC lesion with restricted diffusion is apparent in a wide spectrum of diseases and conditions. Neurological courses and outcomes are good, particularly in patients with isolated SCC lesions. Knowledge of MR imaging findings and the associated spectrum of diseases and conditions might prevent unnecessary invasive examinations and treatments.

Adolescent↗
PubMed2006

Endoscopic hematoma evacuation for hypertensive cerebellar hemorrhage.

OBJECT: The management of spontaneous cerebral hemorrhage remains controversial, particularly the surgical indications. Endoscopic surgery was evaluated for the treatment of spontaneous cerebellar hemorrhage. METHODS: The records of 69 patients with hypertensive cerebral hemorrhage were retrospectively reviewed. Patients treated by endoscopic surgery (n = 10) were compared with patients treated by conventional surgical hematoma evacuation (n = 10) under the same surgical indications. RESULTS: The surgical procedure time, duration of ventricular drainage, extent of hematoma evacuation, necessity for cerebrospinal fluid (CSF) shunt, surgical complications, and outcome at discharge and at 3 months after onset were compared. The extent of hematoma evacuation was greater in the endoscopic group (95.2 %) than in the craniectomy group (90.6 %) but without significant difference. The endoscopic technique (64.5 min) took significantly less time than the craniectomy method (230.6 min, p < 0.0001). The period of ventricular drainage was significantly shorter in the endoscopic group (2.6 days) compared to the craniectomy group (12.3 days, p < 0.01). CSF shunt surgery was required in no patient in the endoscopic group compared to three in the craniectomy group. CONCLUSION: Endoscopic hematoma evacuation is a rapid, effective, and safe technique for the removal of hypertensive cerebellar hemorrhage. Reduction of the mass effect can be accomplished with low risk of recurrent hemorrhage. Release of obstructive hydrocephalus in the early stage may improve the patient's outcome and decrease the requirement for permanent shunt emplacement.

Aged↗
PubMed2006

Effects of calpain and Rho-kinase inhibitors on the acrosome reaction and motility of fowl spermatozoa in vitro.

At the avian body temperature of 40 degrees C, intact fowl spermatozoa require Ca(2+) for the initiation of motility and a combination of both Ca(2+) and homogenized inner perivitelline layer (IPVL) together to induce the acrosome reaction. Within the range of 1-100 micromol/l, neither PD 150606 (a Ca(2+)-dependent calpain inhibitor) nor Y-27632 (an inhibitor of Ca(2+)-dependent Rho-kinase) were able to inhibit the acrosome reaction induced by the presence of Ca(2+) and IPVL. However, PD 150606, although not Y-27632, was able to inhibit sperm motility initiated by Ca(2+), as well as motility initiated by calyculin A -- a specific inhibitor of protein phosphatases, which also initiates sperm motility at 40 degrees C. The addition of PD 150606 did not reduce the ATP concentrations of intact spermatozoa, nor the motility of demembranated spermatozoa. Immunoblot analysis of sperm extract using a polyclonal antibody against calpain 12 revealed a cross-reacting protein of approximately 80 kDa. These results suggest that Rho-kinase is not involved in the regulation of the acrosome reaction or of motility in fowl spermatozoa. In contrast, calpain appears to be involved in the regulation of flagellar movement, but not izn that of the acrosome reaction. Furthermore, it seems that endogenous calpain is present in the cytoplasmic matrix and/or the plasma membrane, but not retained in the axoneme and/or accessory cytoskeletal components.

Acrosome Reaction↗
PubMed2006

Diffusion-weighted MR imaging in carotid angioplasty and stenting with protection by the reversed carotid arterial flow.

BACKGROUND AND PURPOSE: Distal embolism during carotid angioplasty with stent (CAS) can be protected by a flow-reversal device. Diffusion-weighted MR imaging was used to evaluate this protective procedure and perform a comparison with the control. METHODS: Cases of CAS with protection procedures were included in this study. Sixty-five men (68 procedures) and 5 women (5 procedures), with an average age of 68.8 years, having severe carotid stenosis were treated in our department between 2002 and 2004. Eleven cases were treated with the Parodi Anti-Emboli System, with which the internal carotid blood flow is reversed by simultaneous occlusion of the proximal common carotid artery and external carotid artery. Diffusion-weighted MR imaging was performed within 1-3 days after CAS. As controls, data from diffusion-weighted MR imaging in 26 patients who had diagnostic angiography were included. RESULTS: Diffusion-weighted MR imaging in diagnostic angiography showed 11.5% appearance of ischemic spots after procedures. In the Parodi Anti-Emboli System, this value was 18.2%. In the CAS group, ischemic lesions appeared only in the hemisphere ipsilateral to carotid stenosis. There were no ischemic lesions in the opposite carotid or vertebrobasilar territory. The appearance rate of new ischemic spots was not significantly different between the control group and the group of CAS with Parodi Anti-Emboli System (chi2 test, P = .6227, Fisher exact method). CONCLUSIONS: Protection results obtained with the Parodi system were excellent and comparable with conventional angiography.

Aged↗
PubMed2006

Widening spectrum of a reversible splenial lesion with transiently reduced diffusion.

Four patients with encephalitis/encephalopathy and parenchymal lesions accompanying reversible splenial lesions were retrospectively evaluated. In 3 patients, reversible lesions with transiently reduced diffusion were seen in the splenium and symmetrically in the peripheral frontoparietal white matter, clinical signs and symptoms were mild, and recovery was complete. These and previous observations suggest a less severe course and outcome for patients with reversible lesions isolated to the splenium or to the splenium and peripheral frontoparietal white matter.

Brain Diseases↗
PubMed2005

Separation of single-stranded DNAs using DNA conjugates having different migration properties in capillary electrophoresis.

A probe-regulated simultaneous separation (PRESS) using capillary electrophoresis (CE) was developed for separating single-stranded (ss) DNAs. We synthesized two DNA conjugate probes, -(5'-TGTGTGTGT-3')p-AAm(q)- and -(5'-GCCACCAGC-3')m-AAm(n)-, by copolymerizing 5'-methacryloyl-modified ssDNA with acrylamide (AAm), and characterized them in detail. The two probes showed lower electrophoretic mobilities than 5'-methacryloyl-modified ssDNAs. Furthermore, -(5'-TGTGTGTGT-3')p-AAm(q)- showed slightly faster electrophoretic mobility toward the anode than -(5'-GCCACCAGC-3')m-AAm(n)- due to its higher molar fraction of negatively-charged ssDNA. We successfully separated target ssDNAs having the same chain length by using two ssDNA conjugate probes that showed different electrophoretic mobilities, although the separation of these ssDNAs was difficult in conventional capillary electrophoresis systems.

Base Sequence↗
PubMed2005

Free-prefabricated auricular composite graft: a new method for reconstruction following extended hemilaryngectomy.

A free-prefabricated auricular composite graft was applied in two patients who underwent extended hemilaryngectomy. Good phonatory and respiratory functions were obtained without any significant aspiration. Although this reconstructive method is a two-staged procedure involving microsurgical techniques, we believe that it provides a good physiologic reconstruction of the larynx and trachea.

Aged↗
PubMed2005

A patient with untreated tongue carcinoma surviving for 15 years.

A rare case of untreated tongue carcinoma survived for 15 years is presented. A 43-year-old Japanese woman was referred to our department with a 1.8 cm x 1.0 cm white and red non-indurated lesion of the left border of the tongue. The histological examination showed a diagnosis of well-differentiated squamous cell carcinoma. We informed the patient and her family that she had a Stage I tongue carcinoma and needed to receive treatment immediately. However, they refused treatment. Fifteen years later, the patient presented again, complaining of a 55 mm x 40 mm painful gradual-growth swelling of the same site as before, and the clinical stage was T3N2aM0 (Stage IV). The patient agreed to receive radical surgery following preoperative chemoradiotherapy this time. Currently the patient has been free of recurrence for 4 years. Clinical and immunohistochemical features of this rare case are presented and discussed.

Adult↗
PubMed2005

Prostaglandin E2 (PGE2) downregulates interleukin (IL)-1alpha-induced IL-6 production via EP2/EP4 subtypes of PGE2 receptors in human periodontal ligament cells.

OBJECTIVES: Prostaglandin E2 (PGE2) exerts its biological actions via EP receptors, which are divided into four subtypes, EP1, EP2, EP3 and EP4. In the present study, we examined whether PGE2 regulated interleukin (IL)-1alpha-induced IL-6 production in human periodontal ligament (PDL) cells and if so, which subtypes of PGE2 receptors were involved. METHODS: PDL cells were stimulated with vehicle or IL-1alpha in the presence or absence of indomethacin (a cylooxygenase inhibitor), PGE2 or various EP agonists. IL-6 and PGE2 levels were measured by enzyme-linked immunosorbent assay. EP receptor mRNA expression was examined by reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: Indomethacin significantly enhanced IL-1alpha-induced IL-6 production by PDL cells, although it completely inhibited IL-1alpha-induced PGE2 production. Exogenous PGE2 significantly suppressed IL-1alpha-induced IL-6 production. Butaprost, a selective EP2 agonist, and ONO-AE1-329, a selective EP4 agonist, significantly inhibited IL-1alpha-induced IL-6 production, although 17-phenyl-omega-trinor PGE2, an EP1 agonist, and ONO-AP-324, an EP3 agonist, did not affect it. RT-PCR analysis showed that EP2 and EP4 mRNA was expressed in PDL cells. CONCLUSIONS: We suggest that PGE2 downregulates IL-1alpha-induced IL-6 production via EP2/EP4 receptors in human PDL cells.

Cyclooxygenase Inhibitors↗
PubMed2005

Gallbladder aspiration for acute cholecystitis in average-surgical-risk patients.

We conducted a retrospective case note review to assess whether or not gallbladder aspiration can be applied as a temporary measure for the treatment of acute cholecystitis in average-surgical-risk patients. Gallbladder aspiration was performed in 79 consecutive average-surgical-risk patients with acute cholecystitis, who had no indications of emergent surgery and who complained of severe colicky pain. Elective surgery became possible in 92% of patients by gallbladder aspiration. The percentage reached 97 when percutaneous cholecystostomy was added (four patients). Emergent surgery was needed in one patient suffering bile leakage following gallbladder aspiration. Colicky pain was controlled soon after the procedure in most cases. Neither major complications nor mortalities were observed in the following surgical therapies. It is suggested that gallbladder aspiration might be applied as a temporary measure for acute cholecystitis in average-surgical-risk patients, although early surgery should remain the primary choice of therapy in such patients.

Aged↗
PubMed2005

[Short-term results of the Fontan operation in patients with Down syndrome].

Despite an extensive experience with Fontan operation, there is a paucity of information to guide the indication of the procedure in patients with Down syndrome. Of 79 patients who had undergone a Fontan operation in our hospital between 1995 and 2003, 3 had Down syndrome. All 3 patients had complete atrioventricular septal defect with single ventricular physiology. Two patients survived, and 1 died of chylothorax and respiratory infection. The 2 survivors have done well in the short-term without complications. We consider that in appropriately selected patients with Down syndrome in whom biventricular repair is precluded, the Fontan operation is the choice of the procedures.

Child, Preschool↗
PubMed2005

Development of the real-time control (RTC) system for Tokyo sewage system.

Tokyo Metropolitan government has decided to make the maximum possible use of the existing facilities while ensuring safety against inundation and to promote measures also from a software approach by introducing a system capable of minimizing combined sewer overflow, the real-time control system (RTC). A pilot RTC system was installed in August 2002 for the Shinozaki Pumping Station. The RTC system monitors the precipitation volume and the water level in the pipe. Simulations were carried out on the basis of these data. From the results, it was found that with the use of the RTC it is possible to reduce CSO by roughly 50% for small rainfalls with a total precipitation level of 20 mm or less by strong rainwater in the pipe routes at the beginning of the rain. It has also been shown that CSO can be reduced by about 80% through the use of rainfall forecasting.

Computer Simulation↗
PubMed2005

[The tape for pulmonary artery banding].

Pulmonary artery banding remains a useful procedure for special conditions. A 3-month-old girl diagnosed as Down syndrome with atrioventricular septal defect underwent pulmonary artery banding. We used polyester tape smeared with Bone Wax for this pulmonary artery banding. After 7 months period, the tape was easily dissected from surrounding tissue and removed at radical operation. Microscopic appearance showed that the tape was intact and no evidence of inflammation or mineralization. We believe Bone Wax smeared polyester tape accomplishes well as silicone impregnated one.

Biocompatible Materials↗