Biomedical subjects

K Wakabayashi

Publications and source records attributed to K Wakabayashi.

At least 19 recordsLinked to original sources

PubMed2006

Development of inactivated poliovirus vaccine derived from Sabin strains.

In the course of Sabin-inactivated poliovirus vaccine (S-IPV) development, we have established high-yield virus production techniques based on Vero cell micro-carrier cultures. Development of specific ELISA tests to quantify the antigen content of S-IPV has been achieved. To adjust the immunogenicity of S-IPV so as to be comparable with the conventional-IPV, a new formulation was determined using a potency test using rats. The reformulated S-IPV was shown to be efficacious for the immunization of monkeys.

Animals↗

PubMed2006

Effect of morphine on the release of excitatory amino acids in the rat hind instep: Pain is modulated by the interaction between the peripheral opioid and glutamate systems.

Behavioral evidence supports a role for peripheral glutamate receptors in normal nociceptive transmission. In this study, we examined the release of the excitatory amino acids, glutamate and aspartate, in the s.c. perfusate of the rat hind instep by in vivo microdialysis. Antidromic stimulation of the sciatic nerve and noxious stimuli in the form of heat stimulation and local application of capsaicin cream (1%) to the instep caused an increase in excitatory amino acid release. This capsaicin-induced excitatory amino acid release was suppressed by pretreatment with capsaicin. Both systemic (10 mg/kg, i.v.) and local injections (10(-5) M in the perfusate) of morphine inhibited the increase in excitatory amino acid release evoked by local application of capsaicin cream to the instep. This inhibitory effect of morphine was antagonized by naloxone either given systemically (5 mg/kg, i.v.) or locally (10(-5) M). These results suggest that excitatory amino acids are released from small diameter afferent fibers by heat stimulation in the periphery or local application of capsaicin cream, and that activation of opioid receptors, present on the peripheral endings of small-diameter afferent fibers, can regulate noxious stimulus-induced excitatory amino acid release.

Analgesics, Opioid↗

PubMed2006

Pulmonary vein isolation under direct visual identification of the left atrium-pulmonary vein junction using intra-cardiac echography.

INTRODUCTION: Intra-cardiac echocardiography (ICE) which has some benefits, can be used to obtain detailed anatomy of the heart chambers or large vessels, and the catheter positions, and it has been considered useful for improving the outcome of the ablation. In the present study, we performed pulmonary vein isolation (PVI) under real time monitoring of ICE imaging utilizing an ICE catheter placed at the junction of the left atrium (LA) and PVs (LA-PV junction). METHODS: PVI for atrial fibrillation (AF) was performed in 30 cases with drug-resistant AF (mean age: 66-years-old; including 22 males). An ICE catheter utilizing a 9 MHz frequency was inserted into the LA via the atrial septum, and placed at the LA-PV junction. Circumferential ablation was performed in the LA outside of the PV ostium, encircling both the superior and inferior ostia together under ICE imaging. RESULTS: The anatomy of the LA to the PVs and catheter sites were clearly identified by the ICE during the procedure, which enabled a precise and safe catheter manipulation with minimal fluoroscopy. Further, the wall thickness of the PV and LA, and position of the esophagus could be obtained by ICE, facilitating care in adjusting the power and/or duration of the current delivery. CONCLUSION: ICE imaging of the LA-PV junction permitted real time monitoring of the target sites for PVI during the ablation procedure, and was considered a useful technique for performing PVI.

Aged↗

PubMed2006

[Aortic valve replacement for calcified aortic valve and annulus with ultrasonic decalcification].

UNLABELLED: We conducted ultrasonic decalcification on calcified annulus in patients with aortic stenosis (AS) using an ultrasonic operator, Sonopet (UST 2001) prior to aortic valve replacement (AVR). We studied the reliability of this method. SUBJECT AND METHOD: From January 2002 to August 2005, AVR was conducted for AS using the Sonopet in 45 patients, comprising of 18 male and 27 female subjects. The mean age was 73.3 +/- 9.7. RESULT: Artificial valves were successfully inserted at the intra-annular level in 37 patients and at the supra-annular level in 8 patients without conducting annular enlargement. In the patients with narrow annuli of less than 19 mm (23 patients), the preoperative mean annular diameter was 18.2 +/- 1.0 mm, but significantly larger artificial valves with an average diameter of 19.3 +/- 1.5 mm (p=0.003) were successfully inserted. CONCLUSION: AVR was proved to be safe and easy by previous ultrasonic decalcification of the annuls using the Sonopet. This method was very useful because it required no enlargement of aortic annulus.

Aged↗

PubMed2005

Controversy: is Parkinson's disease a single disease entity? Yes.

Parkinson's disease (PD) is a common, and in principle, sporadic, neurodegenerative disorder that occurs in adults. Pathological studies have revealed that in PD, nerve cell loss and Lewy bodies (LB) are distributed widely in the nervous system. Moreover, molecular pathology has made remarkable advances over the last several years, after the identification of alpha-synuclein gene abnormality in familial PD. Extensive pathological findings support the idea that PD is a single disease entity and that there are no cases of PD in which neurodegeneration occurs only in the substantia nigra and in which there are no LBs.

Brain↗

PubMed2005

Accumulation of NEDD8 in neuronal and glial inclusions of neurodegenerative disorders.

NEDD8 (neural precursor cell expressed, developmentally down-regulated 8) is a ubiquitin-like protein that controls vital biological events through its conjugation to members of the cullin family, which are components of certain ubiquitin E3 ligases. Recent studies have shown that NEDD8 is incorporated into Lewy bodies (LBs) in Parkinson's disease, Mallory bodies in alcoholic liver disease and Rosenthal fibres in astrocytoma. In order to examine whether NEDD8 plays a role in the formation of ubiquitinated inclusions, we performed immunohistochemical staining of brain tissue from patients with various neurodegenerative disorders, using an affinity-purified polyclonal antibody raised against NEDD8 that did not cross-react with ubiquitin. In LB disease, NEDD8 immunoreactivity was present in almost all of the LBs and Lewy neurites. Moreover, NEDD8 immunoreactivity was found in a variety of ubiquitinated inclusions, including neuronal and oligodendroglial inclusions in multiple system atrophy, neurofibrillary tangles in Alzheimer's disease, ubiquitinated inclusions in motor neurone disease, and intranuclear inclusions in triplet repeat diseases. These findings suggest that NEDD8 is involved in the formation of various ubiquitinated inclusions via the ubiquitin-proteasome system.

Adult↗

PubMed2005

Tumor induction by azoxymethane (AOM) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in F344 rat gastric mucosa featuring intestinal metaplasia caused by X-irradiation.

Male F344 5-week-old rats were X-irradiated, and 16 weeks after the first dose, azoxymethane (AOM) was injected or 2-amino-1 -methyl-6-phenylimidazo [4,5-b]pyridine (PhIP) was given by intragastric intubation. Tumors in the pylorus of the glandular stomach were observed in 4 out of the 29 animals receiving X-rays + AOM and in 4 out of the 25 animals receiving X-rays + PhIP, 12 months after administration. No such lesions were found in the chemical or X-ray alone groups. Intestinal metaplasia and some induced tumors were positive for CDX2. It was concluded that the presence of intestinal metaplasia may increase sensitivity to the induction of gastric tumors by colon carcinogens.

Animals↗

PubMed2004

Mutagens formed from beta-carbolines with aromatic amines.

Norharman, widely distributed in our environment such as cigarette smoke and cooked foods, is not mutagenic to Salmonella strains, but becomes mutagenic to Salmonella typhimurium TA98 and YG1024 with S9 mix in the presence of aromatic amines, including aniline and o-toluidine. Therefore, we have designated norharman as a "co-mutagen". Since, humans are simultaneously exposed to norharman and aromatic amines in daily life, it is important to clarify the mechanisms of its co-mutagenic action to further understanding of the potential genotoxic effects in humans. Regarding the mechanisms of this action of norharman with aniline, a mutagenic compound, 9-(4'-aminophenyl)-9H-pyrido[3,4-b]indole[aminophenylnorharman (APNH)] is produced by their interaction, and converted to the hydroxyamino derivative which eventually forms the DNA adduct, dG-C8-APNH through possible ultimate reactive forms with esterification, and this induces mutations. Also other aminophenyl-beta-carboline compounds, such as 9-(4'-amino-3'-methylphenyl)-9H-pyrido[3,4-b]indole[amino-3'-methylphenylnorharman (3'-AMPNH)], 9-(4'-amino-2'-methylphenyl)-9H-pyrido[3,4-b]indole [amino-2'-methylphenylnorharman (2'-AMPNH)], 9-(4'-aminophenyl)-1-methyl-9H-pyrido[3,4-b]indole[aminophenylharman (APH)] and 9-(4'-amino-3'-methylphenyl)-1-methyl-9H-pyrido[3,4-b]indole[amino-3'-methylphenylharman (AMPH)], have been found on reaction of norharman or harman with aniline or toluidine isomers. These compounds showed mutagenic and clastogenic actions in bacterial and mammalian cells. Among them, APNH demonstrated the most potent activity, and it was most extensively studied. When APNH was administered as a single dose to F344 rats, severe testicular toxicity was observed after 6 days. Moreover, liver preneoplastic lesions (GST-P-positive foci) in the liver clearly developed in animals fed 10-50 ppm of APNH in the diet for 4 weeks. Since, APNH was detected in 24 h urine of rats upon simultaneous administration with norharman and aniline by gavage, it is likely to be also produced from norharman and aniline in the human body. From these findings, it is suggested that aminophenyl-beta-carboline derivatives may be classified as one of the novel types of endogenous mutagens and carcinogens.

Amines↗

PubMed2004

Prototype of simulation of orthognathic surgery using a virtual reality haptic device.

A maxillofacial simulator can support education and training. In the present study, cutting, separation, and quantitative rearrangement of bone during orthognathic surgery were simulated by means of a haptic device with virtual tactile perception. Computed tomographic (CT) images of two patients with severe jaw deformity, one women and one man, were input into the device. In the woman, Le Fort I osteotomy of the maxilla and sagittal splitting ramus osteotomy of the mandible were initially simulated. During surgery with the haptic device, separation and rearrangement of the maxilla and the ramus of the mandible were initially processed. However, there was discrepancy and overlapping of the ramus with the mandible. Intraoral vertical osteotomy of the right ramus was then performed, with satisfactory results and less discrepancy and interference. The simulation was referred to at surgery, and satisfactory surgical assistance was postoperatively confirmed on CT images. The male patient had severe jaw deformity due to unequal growth between the ramuses, resulting in anterior crossbite. Sagittal splitting ramus osteotomy with rotation of the mandible was successfully simulated. Because of its versatility and functions, the present device was found to be useful for simulating various procedures for orthognathic surgery and thereby three-dimensionally determine surgical movements.

Adult↗

PubMed2004

Computer-assisted morphological analysis of dental casts with maxillary prognathism and reversed occlusion.

The morphologic characteristics of the dentition with maxillary prognathism and reversed occlusion were examined by a computer-assisted dental cast analysing system. Dental casts with normal occlusion, maxillary prognathism and reversed occlusion were selected and measured by a 3D shape measuring system. The dental arches and anteroposterior occlusal curves were approximated numerically by the polynomial expression with a fourth order and second order coefficients, respectively. The coefficients were analysed statistically. Maxillary dental arches with mandibular prognathism showed a more acuminate shape (V-shape) with a significant larger second order coefficient, while arches with reversed occlusion showed more angulate shapes (U-shape) with significantly smaller second order coefficients compared with arches with normal occlusions. However, a notable difference in the shape of the mandibular dental arches was not observed. The mandibular dental arches with maxillary prognathism were positioned backward relative to maxillary dental arches, while the arches with reversed occlusion were positioned forward. The anteroposterior occlusal curves with maxillary prognathism showed larger curvatures in maxilla and mandible, while the curves with reversed occlusion showed smaller curvatures in mandible comparing with the curves with normal occlusion. These results suggest that the present method could offer a useful and objective examination technique for the diagnosis of malocclusion.

Adolescent↗

PubMed2004

Translucency of glass-fibre-reinforced composite materials.

summary The purpose of this study was to examine the translucency of glass-fibre-reinforced composite framework materials. Vectris and FibreKor, as well as an experimental material, were the glass-fibre-reinforced framework materials used. Targis, Sculpture and Estenia were the types of particulate filler composites veneered onto frameworks. Specimens were fabricated from each material, 0.5 and 1.0 mm thick. In addition, laminate specimens, 1.5 mm thick, were fabricated. The translucency of each specimen was evaluated by determining its contrast ratio. The laminate specimens were examined for colour differences. The experimental framework material was more translucent than the enamel composite when it was not coloured, and was nearly as translucent as the dentine composite when coloured. The commercial tooth-coloured framework materials were nearly as translucent as the dentine composite. It was found that it was possible to reproduce the same colour as the veneering dentine composite, when the framework thickness was 0.5 mm, except in the case of FibreKor. Within the limitations of this study, tooth-coloured, glass-fibre-reinforced framework materials are nearly as translucent as the veneering dentine composite, but these materials affect the colour of the prosthesis if the thickness of the framework material is increased beyond a certain point.

Composite Resins↗

PubMed2004

A quantitative investigation of neuronal cytoplasmic and intranuclear inclusions in the pontine and inferior olivary nuclei in multiple system atrophy.

Multiple system atrophy (MSA) is a sporadic neurodegenerative disease characterized by the presence of neuronal and oligodendroglial alpha-synuclein aggregates. To investigate the relationship between the occurrence of neuronal cytoplasmic and intranuclear inclusions (NCIs and NNIs, respectively) and the progression of neuronal degeneration, we performed a quantitative analysis of the pontine and inferior olivary nuclei based on 14 cases of MSA. alpha-Synuclein immunohistochemistry revealed that NCIs and NNIs were present in both brain nuclei in all the cases. The average incidence of NCIs in the pontine and inferior olivary nuclei was 9.1% and 25.8%, respectively, and that of NNIs was 9.2% and 9.0%, respectively. The number of NNIs was strongly correlated with that of neurones in the pontine and inferior olivary nuclei. Although the number of NCIs was not correlated with the neuronal population in both nuclei, the NCI count in patients with moderate MSA was higher than in patients with mild MSA. The NNI count was much higher than the NCI count in the pontine nucleus in four patients, and was the same in the olivary nucleus in three of the four patients. Moreover, the neuronal population in the NNI-predominant cases was significantly higher than in the NCI-predominant cases. These findings suggest that NCI formation is accelerated by the progression of the disease process, and that in MSA, NNI formation is an earlier phenomenon than NCI formation.

Aged↗

PubMed2004

Downregulation of prostaglandin E receptor subtype EP3 during colon cancer development.

BACKGROUND AND AIMS: Involvement of prostaglandin E(2) (PGE(2)) receptors EP(1), EP(2), and EP(4) in the formation of aberrant crypt foci (ACF) and/or intestinal polyps has been suggested. In contrast, EP(3) appears to have no influence on the early stages of colon carcinogenesis. In the present study, we examined expression of PGE(2) receptor subtypes EP(1), EP(2), EP(3), and EP(4) in normal colon mucosa and colon cancers, and assessed the contribution of EP(3) to colon cancer development. METHODS: mRNA expression of PGE(2) receptor subtypes EP(1), EP(2), EP(3), and EP(4) in normal colon mucosa and colon cancers in azoxymethane (AOM) treated mice and rats, and in humans, were examined by reverse transcription-polymerase chain reaction (RT-PCR), quantitative real time RT-PCR, and immunohistochemical analyses. Evaluation of the role of EP(3) was performed by intraperitoneal injection of AOM, using EP(3) receptor knockout mice. Effects of EP(3) receptor activation on cell growth of human colon cancer cell lines were examined using ONO-AE-248, an EP(3) selective agonist. Moreover, EP(3) expression in colon cancer cell lines was analysed with or without 5-aza-2'-deoxycytidine (5-aza-dC) treatment. RESULTS: Expression levels of EP(1) and EP(2) mRNA were increased in cancer tissues. EP(4) mRNA was constantly expressed in normal mucosa and cancers. In contrast, expression of EP(3) mRNA was markedly decreased in colon cancer tissues, being 5% in mice, 9% in rats, and 28% in humans compared with normal colon mucosa, analysed by quantitative real time RT-PCR. Immunohistochemical staining demonstrated the rat EP(3) receptor protein to be expressed in epithelial cells of normal mucosa and some parts of small carcinomas but hardly detectable in large carcinomas of the colon. Colon cancer development induced by AOM in EP(3) receptor knockout mice was enhanced compared with wild-type mice, with a higher incidence of colon tumours (78% v 57%) and mean number of tumours per mouse (2.17 (0.51) v 0.75 (0.15); p<0.05). Expression of EP(3) mRNA was detected in only one of 11 human colon cancer cell lines tested. Treatment with 5 microM of an EP(3) selective agonist, ONO-AE-248, resulted in a 30% decrease in viable cell numbers in the HCA-7 human colon cancer cell line in which EP(3) was expressed. Treatment with 5-aza-dC restored EP(3) expression in CACO-2, CW-2, and DLD-1 cells but not in WiDr cells, suggesting involvement of hypermethylation in the downregulation of EP(3) to some extent. CONCLUSION: The PGE(2) receptor subtype EP(3) plays an important role in suppression of cell growth and its downregulation enhances colon carcinogenesis at a later stage. Hypermethylation of the EP(3) receptor gene could occur and may contribute towards downregulating EP(3) expression to some extent in colon cancers.

Animals↗

PubMed2004

Anti-Hu associated paraneoplastic sensory neuronopathy with upper motor neurone involvement.

Paraneoplastic neurological syndrome is characterised by neuronal degeneration with lymphocytic infiltration in various regions of the central and peripheral nervous systems. Motor neurone symptoms may occur as a remote effect of malignancy, and have been considered because of the involvement of lower motor neurones. A case is reported of an 80 year old woman suffering from paraneoplastic sensory neuronopathy with anti-Hu antibody. Postmortem examination showed adenocarcinoma of the gall bladder and small cell carcinoma of the duodenum. Neuronal loss with lymphocytic infiltration was found in the dorsal root ganglia, brain stem, and cerebellum. Despite the absence of upper motor neurone signs, there was severe loss of Betz cells and degeneration of the bilateral pyramidal tracts. To our knowledge, this is the first demonstration of upper motor neurone involvement in anti-Hu associated paraneoplatic syndrome.

Adenocarcinoma↗

PubMed2004

Expression of neuronal growth inhibitory factor (metallothionein-III) in the salivary gland.

Metallothioneins (MTs) are metal-binding proteins that have been regarded as intrinsic factors for protecting cells and tissues from metal toxicity and oxidants. Among the three major classes of MTs, MT-III is different from other MTs because it has neuronal inhibitory activity and is only expressed in the central nervous system. Recent studies, however, have confirmed that MT-III is also expressed in organs other than the brain. These findings not only indicate that MT-III has a much wider tissue distribution than was originally thought, but also suggest that it might have other unknown activities. In the present study, we examined the human salivary and thyroid glands and demonstrated that the MT-III gene is also expressed in the salivary but not in the thyroid gland. While salivary ducts showed intense immuno-reactivity with anti-MT-III, weak immunoreactivity was observed in acinar cells. This, together with the findings that some neuromodulators (i.e. nerve growth factor, etc.) exist in the salivary gland and that MT-III may participate in the transport in renal tubules, suggest that MT-III may have other functions than cytoprotection in the salivary gland.

Aged↗

PubMed2003

Hypergravity-induced changes in gene expression in Arabidopsis hypocotyls.

Under hypergravity conditions, the cell wall of stem organs becomes mechanically rigid and elongation growth is suppressed, which can be recognized as the mechanism for plants to resist gravitational force. The changes in gene expression by hypergravity treatment were analyzed in Arabidopsis hypocotyls by the differential display method, for identifying genes involved in hypergravity-induced growth suppression. Sixty-two cDNA clones were expressed differentially between the control and 300 g conditions: the expression levels of 39 clones increased, whereas those of 23 clones decreased under hypergravity conditions. Sequence analysis and database searching revealed that 12 clones, 9 up-regulated and 3 down-regulated, have homology to known proteins. The expression of these genes was further analyzed using RT-PCR. Finally, six genes were confirmed to be up-regulated by hypergravity. One of such genes encoded 3-hydroxy-3-methylglutaryl-Coenzyme A reductase (HMGR), which catalyzes a reaction producing mevalonic acid, a key precursor of terpenoids such as membrane sterols and several types of hormones. The expression of HMGR gene increased within several hours after hypergravity treatment. Also, compactin, an inhibitor of HMGR, prevented hypergravity-induced growth suppression, suggesting that HMGR is involved in suppression of Arabidopsis hypocotyl growth by hypergravity. In addition, hypergravity increased the expression levels of genes encoding CCR1 and ERD15, which were shown to take part in the signaling pathway of environmental stimuli such as temperature and water, and those of the alpha-tubulin gene. These genes may be involved in a series of cellular events leading to growth suppression of stem organs under hypergravity conditions.

Arabidopsis↗

PubMed2003

Growth restoration in azuki bean and maize seedlings by removal of hypergravity stimuli.

Hypergravity stimuli, gravitational acceleration of more than 1 x g, decrease the growth rate of azuki bean epicotyls and maize coleoptiles and mesocotyls by decreasing the cell wall extensibility via an increase in the molecular mass of matrix polysaccharides. An increase in the pH in the apoplastic fluid is hypothesized to be involved in the processes of the increase in the molecular mass of matrix polysaccharides due to hypergravity. However, whether such physiological changes by hypergravity are induced by normal physiological responses or caused by physiological damages have not been elucidated. In the present study, we examined the effects of the removal of hypergravity stimuli on growth and the cell wall properties of azuki bean and maize seedlings to clarify whether the effects of hypergravity stimuli on growth and the cell wall properties are reversible or irreversible. When the seedlings grown under hypergravity conditions at 300 x g for several hours were transferred to 1 x g conditions, the growth rate of azuki bean epicotyls and maize coleoptiles and mesocotyls greatly increased within a few hours. The recovery of growth rate of these organs was accompanied by an immediate increase in the cell wall extensibility, a decrease in the molecular mass of matrix polysaccharides, and an increase in matrix polysaccharide-degrading activities. The apoplastic pH also decreased promptly upon the removal of hypergravity stimuli. These results suggest that plants regulate the growth rate of shoots reversibly in response to hypergravity stimuli by changing the cell wall properties, by which they adapt themselves to different gravity conditions. This study also revealed that changes in growth and the cell wall properties under hypergravity conditions could be recognized as normal physiological responses of plants. In addition, the results suggest that the effects of microgravity on plant growth and cell wall properties should be reversible and could disappear promptly when plants are transferred from microgravity to 1 x g. Therefore, plant materials should be fixed or frozen on orbit for detecting microgravity-induced changes in physiological parameters after recovering the materials to earth in space experiments.

Cell Wall↗

PubMed2003

Analysis of estrogenic activity of foodstuffs and cigarette smoke condensates using a yeast estrogen screening method.

Hormone mimics present in our environment are of concern because such agents could potentially reduce fertility and increase sexual dysfunction in wildlife and increase the risk of breast and reproductive organ cancers in man. Therefore, monitoring of the levels of estrogenic compounds in environmental materials is essential in order to prevent their exposure to man and to discover potential harmful effects on human health. In the present study, we analyzed estrogenic activity in 23 foodstuffs and cigarette smoke condensate samples extracted with an organic solvent, using the yeast estrogen screening (YES) system. Three soybean-related foodstuffs (soy sauce, tofu, miso), beer, coffee and cigarette smoke condensates showed clear estrogenic activity in the YES system. HPLC fractionations followed by the YES of these YES-positive samples revealed the presence of many estrogenic compounds in cigarette smoke condensates, whereas the other samples exerted estrogenic activities in only one or two fractions. Genistein was able to be isolated as the major active principle in soy sauce, tofu and miso, its concentration in these three foodstuffs ranging from 0.1 to 394 microg/g or ml. 8-Prenylnaringenin was also isolated from beer extracts as a major compound with estrogenic activity present at 0.22-4.0 ng/ml. Estrogenic activity of 8-prenylnaringenin with YES was 10-times as high as that of genistein, although it was 100-times less than that of 17beta-estradiol. Based on our results in vitro, 10 mg miso and 10 ml beer can be calculated to have similar estrogenic activity to 1 pmole 17beta-estradiol. It is very important that the effects of genistein and 8-prenylnaringenin on human health are elucidated.

Chromatography, High Pressure Liquid↗