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Biomedical subjects

Atsushi Watanabe

Publications and source records attributed to Atsushi Watanabe.

At least 55 records · Page 3Linked to original sources
PubMed2004

New material for Nuss procedure.

The Nuss procedure for pectus excavatum repair has been considered an acceptable method in terms of its decreased invasiveness and excellent cosmetic results. Although a steel bar is usually used for elevating the sternum, we used a titanium alloy plate for pectus excavatum repair for the first time. The characteristics of this plate are that 1) it comes out translucently on X-rays, 2) MRI examination is possible because titanium will not be magnetized, and 3) it is possible to go through the security checkpoint at the airport without setting off the metal detector. Furthermore, the titanium alloy is highly elastic, which reduces complications such as dislocation, and it excels in the conformity to organization. Patients who have received the Nuss operation are forced to somewhat limit their daily life for two or three years until the bar is removed. A plate made from titanium alloy resolves this problem because of its material and it is thought to be an ideal candidate for elevating the sternum during the Nuss operation.

Activities of Daily Living↗
PubMed2004

Development of nitrogen-removal bioreactor using poly(lactic acid) as an energy source.

To control nitrogen such as ammonia in a rearing water of aquatic animals, we developed new bioreactor capable of both nitrification and denitrification. It was consisted of gel-plate immobilized microorganisms and a biodegradable plastic plate composed of three kind of poly(lactic acid) as an energy source of denitrification. When batch treatment experiment by the bioreactor was continuously carried out with an artificial rearing water containing ammonia, nitrogen-removal rate of the bioreactor was approximately 3 g-N/d/m2-gel surface and the activity was maintained for over 3 month without additional energy source. Therefore, the bioreactor would be effective to control nitrogen concentration in rearing water of a closed water circulating system for aquatic animals.

Ammonia↗
PubMed2003

Cloning and characterization of the promoter region of the bovine membrane tethering protein p115 gene and its regulation in mammary epithelial cells.

To elucidate the molecular basis of the expression of the membrane tethering protein p115, a genomic DNA clone including the 5'-flanking region, first exon, and part of the first intron of the p115 gene was isolated from a bovine genomic DNA library in lambdaFIX II. Nine transcriptional initiation sites (at -189, -183, -178, -177, -164, -151, -149, -133 and -129 from the translation initiation site) were determined by the CapSite Hunting method. The 5'-flanking region (a 2.6-kb fragment) of the bovine p115 gene ligated to a luciferase reporter gene displayed promoter activity in primary cultured bovine mammary epithelial (BME) cells and in human MCF-7 breast carcinoma cells. The luciferase reporter gene assays of the promoter deletion constructs suggested the region required for promoter activity of the bovine p115 gene. The region that retained promoter activity contained a potential nuclear respiratory factor-1 (NRF-1) binding site. In both the BME and MCF-7 cells, mutagenesis to impair the NRF-1 consensus sequence in the p115 promoter gave substantially lowered levels of luciferase expression. An electrophoretic mobility shift assay (EMSA) showed that the NRF-1 consensus sequence and nuclear protein formed a complex that was abolished by oligonucleotides containing the authentic NRF-1 binding site, and was also supershifted with an antibody to NRF-1. In luciferase reporter gene assays of the p115 promoter constructs, treatment of the MCF-7 cells with estradiol-17beta (E(2)), insulin, or both stimulated the p115 promoter activity correlating with the cell proliferation rate. These results indicate that the NRF-1 response element in the p115 promoter is important for promoter function, and that it involves the binding of NRF-1. Furthermore, the results suggested that p115 gene transcription is activated by E(2), by insulin, or by both in association with the stimulation of mammary epithelial cell proliferation.

Animals↗
PubMed2003

Repeat operations in the management of clival chordomas: palliative surgery.

Some chordomas have a very poor prognosis because of their aggressive growth nature, but the efficacy of repeat operations for these cases has not been well documented. This report concerns 3 patients with aggressive chordoma of the clivus, who underwent operations 6 to 12 times over a period of 8 to 17 years because of symptomatic regrowth. Overall mean interval between repeat operations was 18 months with a range from 5 to 57 months and survival times were 9 to19 years after the first surgery. Main symptoms before each operation were diplopia and visual disturbance. Repeat palliative operations by intentional extradural debulking of the tumour to decompress offending neural structures, as well as maximal removal of the tumour, using appropriate skull base approaches, can mitigate progressive symptoms, and may result in better quality and some prolongation of life, although our patients gradually deteriorated neurologically throughout the clinical course.

Chordoma↗
PubMed2003

Lentivirus-mediated expression of angiostatin efficiently inhibits neovascularization in a murine proliferative retinopathy model.

Ischemic retinal diseases, such as diabetic retinopathy, retinopathy of prematurity, and age-related macular degeneration, are a major cause of blindness worldwide. Angiostatin is an internal peptide fragment of plasminogen that inhibits endothelial proliferation in vitro and tumor growth in vivo. We now demonstrate that HIV vector encoding angiostatin (HIV-angiostatin) can inhibit retinal neovascularization in a mouse model of proliferative retinopathy. Intravitreal injections of HIV-angiostatin led to stable expression of the angiostatin gene in retinal tissue. Retinal neovascularization was histologically quantitated by a masked protocol. Retinal neovascularization in the eye injected with HIV-angiostatin was reduced in 90% (9/10; P=0.025) of animals, compared with the eye injected with phosphate-buffered saline. Reduction of histologically evident neovascular nuclei per 6-microm section averaged 68%, with maximal inhibitory effects of 87%. Neovascularization was not reduced in the eyes injected with HIV vector encoding enhanced green fluorescent protein. This is the first report that HIV-angiostatin can reduce neovascular cell nuclei in a murine proliferative retinopathy model. These data suggest that the anti-angiogenic activity of angiostatin has therapeutic potential for the treatment of retinal neovascularization.

Angiostatins↗
PubMed2003

Large bronchial cyst causing compression of the left atrium.

We describe here a case with a large bronchogenic cyst treated by surgical resection, who presented with evidence of left atrial overload on electrocardiogram (ECG). The 50-year-old male patient presented with the chief complaint of heaviness in the chest on exertion. An ECG revealed evidence of left atrial overload, and echocardiography and imaging revealed a mass having a maximum diameter of 9 cm on the cranial aspect of the left atrium, caudal to the tracheal bifurcation. The patient was treated by surgical resection of the cystic mass via right anterolateral thoracotomy. His postoperative course was satisfactory and the patient was relieved of his main symptom.

Bronchogenic Cyst↗
PubMed2003

Multidisciplinary treatment by pneumonectomy, PMX and CHDF in a case of pulmonary suppuration complicated with septic shock.

A 68-year-old male, who had suffered from pulmonary tuberculosis with cavities on the right upper lobe, developed breathlessness, bloody sputum, right chest pain and fever. His laboratory data on admission showed severe infection or sepsis (WBC 2,600/mL, CRP 40.2 mg/dL), and his respiratory condition rapidly worsened. In the intensive care unit (ICU) he was given continuous hemodiafiltration (CHDF), but his respiratory condition failed to improve and it was therefore decided to perform a right pneumonectomy. His severe hypoxemia was resolved but because high dose catecholamines medication was still required, polymyxin-B immobilized fiber (PMX) and CHDF were performed. The operation was successful and he was transferred from the ICU to a general ward seven days postoperatively. The vicious circle of septic shock presenting in this case was successfully broken by the pneumonectomy and subsequent treatment by PMX and CHDF, which eliminated the causative factors of sepsis. (Ann Thorac Cardiovasc Surg 2003; 9: 319-22)

Aged↗
PubMed2002

Effects of Rho-kinase inhibitor on vasopressin-induced chronic myocardial damage in rats.

The aim of this study was to develop a new model of vasopressin-induced chronic myocardial damage based on sustained ST-segment depression in electrocardiogram (ECG) with progression of myocardial fibrosis in rats. Furthermore, using this model, we examined the prophylactic potential of fasudil, a Rho-kinase inhibitor, against myocardial damage induced by vasopressin. In 10-week old male Donryu rats, intravenous administration of arginine vasopressin (0.5 iu/kg) induced significant ST-segment depression. Two days and one week after the administration of vasopressin, ST-segment depression was -0.19 +/- 0.02 and -0.14 +/- 0.02 mV, respectively. Fasudil (10 and 30 mg/kg, p.o.) significantly attenuated the ST-segment depression induced by vasopressin. One week after the administration of vasopressin, the percent area of myocardial fibrosis in control animals (0.42 +/- 0.11%, p < 0.01) was significantly greater than that in normal animals (0.05 +/- 0.01%). Fasudil (10 and 30 mg/kg) significantly prevented the development of the fibrosis. We present a new model of chronic myocardial damage based on sustained ST-segment depression with progression of myocardial fibrosis in rats, and suggest that this model may be useful to investigate the treatment of chronic angina. Inhibition of Rho-kinase is efficacious in preventing the ECG change and development of fibrosis induced by vasopressin in this model.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed2002

An experimental study of vascular dynamics by an acceleration plethysmogram using artificial circulation devices.

Plethysmogram has been widely known as a conventional non-invasive simple method to obtain information on peripheral circulatory kinetics. We made a quantitative assessment of the relationships between the various circulatory parameters, using the simple conventional measurement method of treating acceleration plethysmograms (the second derivatives of digital plethysmograms) as indicators of peripheral circulation kinetics. We designed a prototype model peripheral circulatory circuit, using an artificial heart, for the purpose of clarifying the relationship between physical factors and plethysmograms. In our models of the peripheral circulatory system, we made use of various types of matching silicon tubes, as well as canine carotid arteries, as substitutes for human arteries. We evaluated the mechanical characteristics, such as the pressure and volume characteristics of the silicon tubes and canine carotid arteries. Plethysmogram alterations were measured using a photoelectric digital plethysmogram. When we examined the acceleration plethysmogram b/a values, which indicate blood vessel extensibility and hardness, and the d/a values, which we were able to use as an index of peripheral circulatory kinetics, it was clear from out model testing that canine carotid arteries displayed b/a values that were closest to those found in the human fingertip; among artificial tubes, the closest was a tube with a diameter of 4 mm (0.18 mm in thickness). The b/a values of all types of tubes declined when the compliance of the arterial system was increased, and it was confirmed through model testing that b/a values are an indicator of blood vessel extensibility.

Assisted Circulation↗
PubMed2002

Anisotropic conduction properties in canine atria analyzed by high-resolution optical mapping: preferential direction of conduction block changes from longitudinal to transverse with increasing age.

BACKGROUND: Anisotropic conduction properties may provide a substrate for reentrant arrhythmias. We investigated the age-dependent changes of structural and functional anisotropy in isolated right atria from infant (1 to 2 months), young (6 to 12 months), and old (6 to 10 years) dogs. METHODS AND RESULTS: The histology of the mapped atrial tissues (a small subepicardial area, 2.8x4.2 mm) was characterized by an age-dependent increase of myofiber width and fat cell infiltration between myofibers. Cx43 was distributed homogeneously over the entire cell surface in infant dogs, whereas it progressively polarized to the cell termini with increasing age. The activation sequences were analyzed by high-resolution optical mapping using a voltage-sensitive dye. Activation fronts from the pacing site proceeded more rapidly along fiber orientation (longitudinal) than across it (transverse). Infant dogs showed "elliptical" isochrones with a smooth transition between longitudinal and transverse propagation, whereas old dogs had a "square" pattern with a sharp transition. Conduction block occurred predominantly during longitudinal propagation in infant dogs but during transverse propagation in old dogs. The shape of the wave front and the degree of lateral uncoupling seemed to decide the preferential direction of block. A zigzag activation causing an extremely slow transverse conduction was observed only in old dogs. CONCLUSIONS: Along with the age-dependent structural anisotropy, the preferential direction of block changed from longitudinal to transverse in association with a change in the wave front configuration. A zigzag propagation based on lateral uncoupling would predispose the elderly to multiple reentry and a higher incidence of atrial fibrillation.

Action Potentials↗
PubMed2002

CLAC: a novel Alzheimer amyloid plaque component derived from a transmembrane precursor, CLAC-P/collagen type XXV.

We raised monoclonal antibodies against senile plaque (SP) amyloid and obtained a clone 9D2, which labeled amyloid fibrils in SPs and reacted with approximately 50/100 kDa polypeptides in Alzheimer's disease (AD) brains. We purified the 9D2 antigens and cloned a cDNA encoding its precursor, which was a novel type II transmembrane protein specifically expressed in neurons. This precursor harbored three collagen-like Gly-X-Y repeat motifs and was partially homologous to collagen type XIII. Thus, we named the 9D2 antigen as CLAC (collagen-like Alzheimer amyloid plaque component), and its precursor as CLAC-P/collagen type XXV. The extracellular domain of CLAC-P/collagen type XXV was secreted by furin convertase, and the N-terminus of CLAC deposited in AD brains was pyroglutamate modified. Both secreted and membrane-tethered forms of CLAC-P/collagen type XXV specifically bound to fibrillized Abeta, implicating these proteins in beta-amyloidogenesis and neuronal degeneration in AD.

Alzheimer Disease↗
PubMed2002

Large-scale preparation, purification, and characterization of hyaluronan oligosaccharides from 4-mers to 52-mers.

Hyaluronan (HA) was depolymerized by partial digestion with testicular hyaluronidase and separated into size-uniform HA oligosaccharides from 4-mers to 52-mers by anion exchange chromatography after removal of the hyaluronidase. The purity and size of each HA oligosaccharide was confirmed by using HPLC analyses, FACE, and ESI-MS. (1)H and (13)C NMR assignments and elemental analyses were obtained for each HA oligosaccharide. Endotoxins, proteins, and DNA were absent or in trace amounts in these HA oligosaccharides. Gram/mg-scale hyaluronan oligosaccharides were obtained from 200 g of HA starting material. These pure, size-uniform, and large range of HA oligosaccharides will be available for investigating important biological functions of HA, such as for the determination of the size(s) of HA oligosaccharides that induce angiogenesis or mediate inflammatory responses, and to interact with HA-binding proteins and receptors both in in vitro and in vivo studies.

Chromatography, High Pressure Liquid↗
PubMed2002

Start-up behavior of viscoelastic fluid flow near a capillary entry.

The effect of elasticity on the capillary entry flow development process was investigated by applying a laser doppler velocimeter (LDV) and flow visualization. The fluid filling the test section was kept at rest under a pressure of compressed air or a natural head and then a valve below the capillary was quickly opened to start the flow. Although the development of the capillary entry flow field of a Newtonian fluid is virtually quasi-steady, it takes a considerable time for a viscoelastic PAA-solution to attain its terminal regime. The transient behavior of the flow rate of the PAA-solution is attributed to the gradual development process of the flow field upstream from the entry.

Capillary Action↗
PubMed2002

[A trial production of a table of the optical crystallographic characteristics of crystalline drugs including crystal habits (study of crystalline drugs by means of a polarizing microscope. XIX].

It was clarified in previous report that the predominant faces of crystal habits mainly coincide with the morphologic crystal face at (001), (010), or (100), and therefore the two measurable key refractive indices are closely related to the principal sections of the two axial wave surfaces and coincide with the one or two of the three principal refractive indices. The three principal refractive indices of biaxial crystalline drugs were measured and tabulated in the "General Information" section of the National Formulary compiled by the American Pharmaceutical Association. A series of studies was conducted to measure the key refractive indices of the crystalline drugs listed in the Japanese Pharmacopoeia X or XI so that the data could be used to improve the quantitative analysis of their crystal habits. The purpose of the present study was to examine data on both the key and principal refractive indices and attempt to produce a general authorized table of optic crystallographic characteristics, including crystal habits, for simpler and more reliable polarizing microscopy studies.

Crystallization↗
PubMed2002

Retroperitoneal bronchogenic cyst: a case report.

A 46-year-old woman presented with a 1-year history of progressive left-arm numbness. A cyst below the left hemidiaphragm was discovered incidentally when a CT scan was performed to examine the thymus for a suspected tumor. A thymic mass was found. MRI indicated that the cyst contained proteinaceous fluid. The thymoma was approached through a median sternotomy and resected, but the cyst was found to be infradiaphragmatic. A separate, left paraspinal incision was made to access the retroperitoneum, and the cyst was resected. Histologic examination showed that the cyst was bronchogenic in origin. Retroperitoneal bronchogenic cysts are very rare, and only four cases have been reported in the English-language literature.

Bronchogenic Cyst↗