Biomedical subjects

N Ikeda

Publications and source records attributed to N Ikeda.

At least 19 recordsLinked to original sources

PubMed2006

Spontaneous formation of vanadium "molecules" in a geometrically frustrated crystal: AlV2O4.

We investigated the charge-ordered (CO) state in spinel AlV2O4 by electron diffraction, synchrotron x-ray diffraction, and magnetic measurements. It was found that the CO structure appearing below 700 K is characterized by the formation of V clusters (heptamers), each of which is consisting of 7 vanadium atoms and is in a spin-singlet state as a total. Theoretical consideration indicates that this unique molecularlike V heptamer is stabilized by a strong bonding of vanadium t(2g) orbitals.

Journal Article↗

PubMed2006

Awareness of the Japanese Society of Hypertension Guidelines for the Management of Hypertension (JSH 2000) and compliance to its recommendations: surveys in 2000 and 2004.

Clinic physicians' awareness of the Japanese hypertension guideline (JSH 2000) and compliance with its recommendations were assessed to derive policy implications for effective blood pressure control. Data were obtained from two postal questionnaire surveys conducted in 2000 and 2004, and subjects were 896 and 1425 clinic physicians, respectively, who were engaged in general internal medicine. Recognition rates of JSH 2000 were 63.1% (n = 822) before its announcement in 2000 and 94.4% (n = 1400) in 2004. Rates of access, familiarity and utilisation of JSH 2000 were 87.0, 81.6 and 68.9%, respectively (n = 1400) in 2004. As for major management strategies for low-risk hypertension: in 2000, for patients with 140-149/90-94 mmHg, 81.5% of 812 respondents performed lifestyle modification, and 11.2% prescribed medicines, whereas for patients with 150-159/95-99 mmHg, 71.7% of 807 respondents prescribed medicines, and 24.3% conducted lifestyle modification; in 2004, 90.0% of 1384 respondents conducted lifestyle modification, 22.6% prescribed medicines, 2.5% referred patients to other facilities, and 6.4% did nothing. In 2004, 68.9% of 1388 respondents agreed with the new definition of hypertension, whereas 17.1% preferred 160/95 mmHg. Respondents' age (P<0.05) and a percentage of hypertensives in daily patient load (P<0.0005) significantly associated with the choice of the old criteria. In conclusion, JSH 2000 achieved a substantial improvement in clinic physicians' awareness and their compliance to its recommendations on low-risk hypertension management. One of the strategies for further enhancement in their compliance with JSH 2004 would be its dissemination to those who are old and/or do not see hypertensive patients so frequently.

Antihypertensive Agents↗

PubMed2006

Alkali burns of the eye: effect of immediate copious irrigation with tap water on their severity.

PURPOSE: To examine the effect of immediate irrigation on ocular alkali burn. METHODS: Information on the injury, immediate irrigation, and ocular findings was retrospectively obtained from each patient's record. RESULTS: 36 patients (49 eyes) irrigated their eyes with tap water (the irrigation group) and 17 patients (29 eyes) did not (no irrigation group). The mean age of patients in the irrigation and no irrigation groups was 30 and 53 years, respectively. According to Hugher's classification, 76% of eyes in the irrigation group had grade 1 injury, while 86% of eyes in the no irrigation group had grade 2 injuries. Mean time from the injury until healing was 8 days in the irrigation group and 29 days in the no irrigation group, respectively. CONCLUSION: Immediate copious irrigation with tap water reduced the severity in alkali burns of the eye and shortened the healing time.

Adult↗

PubMed2005

An organic thyristor.

Thyristors are a class of nonlinear electronic device that exhibit bistable resistance--that is, they can be switched between two different conductance states. Thyristors are widely used as inverters (direct to alternating current converters) and for the smooth control of power in a variety of applications such as motors and refrigerators. Materials and structures that exhibit nonlinear resistance of this sort are not only useful for practical applications: they also provide systems for exploring fundamental aspects of solid-state and statistical physics. Here we report the discovery of a giant nonlinear resistance effect in the conducting organic salt theta-(BEDT-TTF)2CsCo(SCN)4, the voltage-current characteristics of which are essentially the same as those of a conventional thyristor. This intrinsic organic thyristor works as an inverter, generating an alternating current when a static direct-current voltage is applied. Whereas conventional thyristors consist of a series of diodes (their nonlinearity comes from interface effects at the p-n junctions), the present salt exhibits giant nonlinear resistance as a bulk phenomenon. We attribute the origin of this effect to the current-induced melting of insulating charge-order domains, an intrinsically non-equilibrium phenomenon in the sense that ordered domains are melted by a steady flow.

Journal Article↗

PubMed2005

Ferro-type orbital state in the Mott transition system Ca2-xSrxRuO4 studied by the resonant x-ray scattering interference technique.

We have succeeded in detecting ferro-type orbital states in Ca2-xSrxRuO4, which is the first outcome in a 4d Mott transition system by the resonant x-ray scattering interference technique. For x=0 (Mott insulator), the resonant signal for d(xy) orbital ordering is observed even at room temperature, in which the Jahn-Teller distortion is negligible. The signal disappears near the metal-insulator transition. On the other hand, in a metallic phase for x=0.5, orbital polarization with d(yz/zx) character dominates. With lowering temperature, the magnitude of the resonant signal slightly decreases owing to the additional influence of the gamma band with d(xy) character.

Journal Article↗

PubMed2005

Genotoxicity studies on dietary diacylglycerol (DAG) oil.

Dietary diacylglycerol (DAG) oil is an edible oil enriched in DAG (more than 80%). A recent investigation indicated that DAG oil or its components may have beneficial effects on the prevention and management of obesity. We evaluated the genotoxic potential of DAG oil using standard genotoxicity tests. Bacterial reverse mutation assay (Ames test), the chromosomal aberration assay in cultured Chinese hamster lung cells (CHL/IU), and a bone marrow micronucleus assay in ICR CD mice were employed in the present study. In addition we have tested the possibility that genotoxic substances may be formed during cooking, heated DAG oil (HDG) was prepared by batch frying potato slices in the oil at 180 degrees C for 8 h/day for three consecutive days. Therefore, genotoxicity tests were also performed on HDG. Results obtained did not show any genotoxic effect on either unheated DAG oil (UDG) or HDG. We conclude that there are no safety concerns on the genotoxicity of DAG oil under the conditions for normal use.

Animals↗

PubMed2005

Nano-sized domains related to dielectric anomaly in YFe2O4-delta.

We examined microstructures related to the charge ordering in YFe2O4-delta, by transmission electron microscopy. It is found that two types of characteristic diffuse scatterings appear at room temperature. One is characteristic diffuse streaks elongated along the [0001] direction through the (1/3 1/3 2/3 0)-type reciprocal positions and the other is diffuse spots at (1/3 - eta 1/3 - eta 2/3 + 2eta 0)-type incommensurate positions (eta approximately 0.066). Real-space images revealed that the former diffuse scattering is related to nano-domains due to the charge ordering and the latter one is related to those due to vacancy ordering. The presence of the nano-sized domains should be strongly related to the dielectric anomalies found in YFe2O4-delta.

Journal Article↗

PubMed2005

[Left-sided adult Bochdalek hernia with right lung cancer; report of a case].

Bochdalek hernia is a common congenital anomaly in neonatal patients with risky respiratory distress and high mortarity, but can be seen in adults. A case of left-sided adult Bochdalek hernia with right lung cancer is reported. A 71-year-old female had been performed radition therapy for lung cancer in the right lower lobe. She was admitted to our hospital due to advanced lung cancer and pneumonia. On the 7th day after admission, she felt dyspnea and abdominal distention due to herniation of the stomach through the posterolateral defect of the diaphragma into the left hemithorax. Her condition did not allow us a radical surgery of Bochdalek hernia, so that we performed a palliative surgery, that is reduction of the stomach and gastrostomy. After surgery, her respiratory distress was lightened and she came to be able to ingest. She was less uncomfortable until she died due to progression of the lung cancer.

Aged↗

PubMed2004

Presence of staphylococcal exfoliative toxin A in sera of patients with atopic dermatitis.

BACKGROUND: It has been reported that the toxins that Staphylococcus aureus produces are associated with the exacerbation of atopic dermatitis (AD). It has been shown in many studies that staphylococcal enterotoxin (SE) A and SEB contribute to AD by humoral immunity through IgE production as a superantigen. On the other hand, little attention has been paid to the relationship between AD and exfoliative toxin x (ETx). OBJECTIVE: We investigated the toxins that are frequently detected from the skin of patients and how these toxins affect AD. METHODS: S. aureus, isolated from the skin of 100 patients with mild to severe AD, were examined for the producibility of toxins by polymerase chain reaction. Serum samples were obtained from 21 patients with mild and moderate AD. The levels of SEB, ETA, total IgE, specific IgE, and specific IgG in sera were measured by ELISA. RESULTS: SEB was most frequently detected from S. aureus on the skin of these patients as previously reported. And ETx, to which little attention has been paid so far, was frequently detected next to SEB. Furthermore, ETA was detected from the sera of almost all the AD patients. SEB was not detected at all. Although the level of ETA in the AD group was significantly higher than that of controls, ETA-specific IgE was not detected from their sera. High levels of ETA tended to be detected from infantile patients. Although there were no significant differences in the levels of ETA-IgG between AD and the controls, its prevalence was more than twice as high as the controls in AD. CONCLUSION: These results suggest that many AD patients were exposed to ETx. We conclude that ETx may contribute to exacerbation of AD, particularly in infants, by a mechanism that is not through specific IgE production, unlike SEB.

Adolescent↗

PubMed2004

Nicorandil versus isosorbide dinitrate as adjunctive treatment to direct balloon angioplasty in acute myocardial infarction.

OBJECTIVE: To compare the effects of nicorandil (a hybrid ATP sensitive potassium channel (K+(ATP) channel) opener/nitric oxide donor) with those of isosorbide dinitrate (ISDN) on myocardial microcirculation and cardiac function in patients with acute myocardial infarction (AMI) who had undergone reperfusion treatment by direct balloon angioplasty. DESIGN: Double blind randomised study. PATIENTS: 60 patients with AMI in Killip class I. INTERVENTIONS: Patients were assigned into two treatment groups: a nicorandil group (n = 30) and an ISDN group (n = 30). Each drug was infused intravenously at 6 mg/h for 72 hours starting at admission and was administered directly to the treated coronary artery immediately after angioplasty. RESULTS: Compared with ISDN, nicorandil more frequently caused recovery of ST segment elevation just after reperfusion (15 of 27 (55.5%) in the nicorandil group v 5 of 26 (19.2%) in the ISDN group, p = 0.006). The nicorandil group had higher values of averaged peak velocity 40 minutes after reperfusion (mean (SD) 24.8 (13.3) cm/s v 16.0 (11.1) cm/s, p = 0.045) and higher values of regional wall motion of the infarcted area three weeks after onset of AMI (-1.78 (1.11) v -2.50 (1.04) SD/chord, p = 0.046). CONCLUSIONS: A combination of nicorandil drip infusion starting before reperfusion and intracoronary injection immediately after reperfusion is more effective than a similarly performed infusion of ISDN in preserving myocardial microcirculation in the reperfused AMI area. The nicorandil regimen resulted in better left ventricular regional wall motion.

Angioplasty, Balloon↗

PubMed2003

Induction of cutaneous delayed hypersensitivity reactions in mice sensitized with intragastrically administered hapten: activation of Langerhans cells in the sensitization and elicitation phases.

BACKGROUND: As seen in atopic dermatitis, allergic diseases often produce lesions both in the gastrointestinal tract and the skin, suggesting the involvement of an immunological relationship between the two organs in the pathogenesis. OBJECTIVES: To study the role of gastric and epidermal Langerhans cells (LCs) in the sensitization and elicitation phases, respectively, of cutaneous delayed-type hypersensitivity (DTH) reactions to intragastrically administered hapten. METHODS: BALB/c mice, which were subjected to intragastric administration of trinitrochlorobenzene 5 days previously, received an elicitative challenge of the same hapten to the ear skin. Sections of the ear were immunostained for CD4 and CD8. Epidermal sheets of the ear and epithelial sheets of the forestomach were immunostained for I-A and observed under a confocal laser scanning microscope. RESULTS: Cutaneous DTH reactions were induced in mice, as demonstrated by an increase in ear thickness and a prominent infiltration of CD4+ and CD8+ lymphocytes at 24-36 h after the elicitative challenge. In the elicitation phase, epidermal LCs showed a significant increase in size, indicating in vivo activation, at 24 h. In the sensitization phase, gastric LCs increased in size at 2 h, became round at 6 h, and decreased in number at 24 h, possibly representing the sequential events of LC activation and migration from the epithelium. CONCLUSIONS: The present study demonstrated that gastric LCs and epidermal LCs were activated in vivo in the sensitization and elicitation phases, respectively, of cutaneous DTH reactions in orally sensitized mice.

Animals↗

PubMed2002

Ordered charge asphericity around dysprosium and structural deformation in DyB2C2.

The orbitally ordered phase of DyB2C2 has been studied by nonresonant x-ray diffraction with high-brilliance synchrotron radiation. From the condition of diffraction, the symmetry property of the charge distribution around dysprosium has been concluded at the quadrupolar level. The quantitative inspection, furthermore, indicates that the observed signals cannot be interpreted as arising only from the 4f electrons of dysprosium responsible for the ordering; instead, the experiment can be described rather well by considering a distortion of the metaloid network concomitant with the ordering.

Journal Article↗

PubMed2002

Forensic significance of conduction system abnormalities as a precise cause of accidental death.

We examined the pathology findings of the cardiac conduction system in 42 human autopsies who were considered to have died an accidental death. Abnormalities in serial sections of the conduction system were found in seven and of these three had an accessory pathway in the conduction system. In one of these there was mild Ebstein's anomaly (ME), two had fibromuscular dysplasia of the atrioventricular node artery with mitral valve prolapse, and two others had abnormal routes showing fragmentation of the bundle of His with ME. A full investigation of the cardiac conduction system can therefore be useful for determining the precise cause in cases of accidental death.

Accidents↗

PubMed2002

Phosphorylated tyrosine-containing proteins in primary lung cancer correlates with proliferation and prognosis.

To determine the usefulness of tyrosine phosphorylation in evaluating biological characteristics, we attempted to evaluate the relationship between the amount of phosphorylated tyrosine-containing proteins and clinicopathological factors, cell proliferation and outcome in non-small cell lung cancer. To evaluate phosphorylated tyrosine-containing proteins we used 96 surgically resected materials of non-small cell lung cancer and normal peripheral lung, while immunohistochemical evaluation was performed. Cell proliferating ability was evaluated using the labelling index of proliferating cell nuclear antigen-positive nuclear staining cells. There were statistically significant differences between the expression levels of phosphorylated tyrosine-containing proteins of normal and cancerous tissues (P<0.0001). Evaluations based on clinicopathological factors apart from histopathological differentiation, showed no statistically significant differences of phosphorylated tyrosine-containing proteins expression. However, phosphorylated tyrosine-containing proteins correlated with cell proliferation activity evaluated (P((Low, High))<0.0001; P((Low, Int)) <0.0001; P((Int, High))<0.0001). Furthermore, non-small cell lung cancer cases with high expression and intermediate expression of phosphorylated tyrosine-containing proteins had a significantly shorter disease-free postoperative survival than those with low expression of phosphorylated tyrosine-containing proteins using log-rank analysis (P((Low, Int)) <0.0028; P((Low, High))=0.0002). Furthermore, phosphorylated tyrosine-containing proteins expression level statistically contributed to disease-free survival in Cox's proportional hazard model. Therefore, phosphorylated tyrosine-containing proteins in non-small cell lung cancer tissues seem to reflect its biological malignancy, and this evaluation may be valuable for constructing the most appropriate therapeutic strategy.

Aged↗

PubMed2002

Liver fibrosis increases the risk of intrahepatic recurrence after hepatectomy for hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) commonly develops in patients with chronic hepatitis. Intrahepatic recurrence after hepatectomy often includes nodules of new tumour in the liver remnant. The aim of this study was to examine hepatitis-related factors that might predict this type of recurrence. METHODS: The influence of various hepatitis-related factors on intrahepatic recurrence of HCC was studied by multivariate analysis in 138 patients who underwent curative resection and were followed for more than 2 years. RESULTS: The Cox proportional hazard model showed that histological evidence of fibrosis of the underlying liver was the most significant predictive factor for intrahepatic recurrence (P = 0.001). Serum albumin level was also significantly associated with recurrence (P = 0.038). The relative risks of histological fibrosis and low serum albumin levels were 8.9 and 1.7 respectively. Among tumour-related factors, only tumour size was significantly associated with recurrence (P = 0.017). Major hepatectomy was also an independent risk factor for intrahepatic recurrence (P = 0.004). CONCLUSION: Histological evidence of fibrosis and low serum albumin levels are useful predictors of intrahepatic recurrence after hepatectomy, presumably owing to metachronous multifocal tumour in the liver remnant.

Adolescent↗

PubMed2001

Distribution of tetracaine and its metabolite in rabbits after high versus normal spinal anesthesia.

High spinal anesthesia is one cause of sudden death associated with the spinal anesthesia. We did animal experiments to verify high spinal anesthesia by analyzing tetracaine and its metabolite, p-butylaminobenzoic acid in tissue samples. Tetracaine (0.25% in 10% glucose solution) 0.21-0.28 mg/kg was administered to two groups of rabbits to induce high and normal spinal anesthesia. Tetracaine and the metabolite in rabbit tissues were analyzed by gas chromatography-mass spectrometry, as a free base for tetracaine and as tert-butyldimethylsilyl derivative for the metabolite. In the group given high spinal anesthesia, levels of the metabolite in the brain stem were higher than in the cerebrum, cerebellum and whole blood. On the other hand, in the group given normal spinal anesthesia, the opposite results were obtained. Therefore, high spinal anesthesia induced by tetracaine can be diagnosed by comparing the concentrations of metabolite in whole blood, cerebrum, cerebellum and brain stem.

Anesthesia, Spinal↗

PubMed2001

Influence of angiogenetic factors and matrix metalloproteinases upon tumour progression in non-small-cell lung cancer.

We attempted to investigate immunohistochemical expression of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), platelet-derived growth factor (PD-ECGF), c-erbB-2, matrix metalloproteinase-2 (MMP-2), and MMP-9 using surgical specimens of 119 non-small-cell lung carcinoma (NSCLC) cases and to evaluate the relationship between the expression levels of each molecule and clinicopathological factors or prognosis. VEGF expression levels were significantly associated with the local invasion (P = 0.0001), lymph node involvement (pN-factor) (P = 0.0019), pathological stage (p-stage) (P = 0.0027) and lymphatic permeation (P = 0.0389). PD-ECGF expression levels were associated with pN-factor (P = 0.0347). MMP-2 expression levels were associated with pN-factor (P = 0.004) and lymphatic permeation (P = 0.0056). Also, MMP-9 expression levels showed a significant correlation to local invasion (P = 0.0012), pN-factor (P = 0.0093) and p-stage (P = 0.0142). Multivariate analysis showed VEGF to be the most related to local invasion (P = 0.0084), and MMP-2 was the only factor with significant independent impact on lymphatic permeation (P = 0.0228). Furthermore, log-rank analysis showed significant association with poor survival by VEGF, bFGF, MMP-2 and MMP-9. Especially, combined overexpression of VEGF and MMP-2 revealed poor prognosis, our study might provide a basis for the better evaluation of biological characteristics and a new therapeutic strategy based on chemotherapy.

Adult↗

PubMed2001

A remodeling system of the 3'-sulfo-Lewis a and 3'-sulfo-Lewis x epitopes.

It has been reported that the chemically synthesized 3'-sulfo-Le(a) and 3'-sulfo-Le(x) epitopes have a high potential as a ligand for selectins. To elucidate the physiological functions of 3'-sulfated Lewis epitopes, a remodeling system was developed using a combination of a betaGal-3-O-sulfotransferase GP3ST, hitherto known alpha1,3/1,4-fucosyltransferases (FucT-III, IV, V, VI, VII, and IX) and arylsulfatase A. The pyridylaminated (PA) lacto-N-tetraose (Galbeta1-3GlcNAcbeta1-3Galbeta1-4Glc) was first converted to 3'-sulfolacto-N-fucopentaose II (sulfo-3Galbeta1-3(Fucalpha1-4)GlcNAcbeta1-3Galbeta1-4Glc)-PA by sequential reactions with GP3ST and FucT-III. The 3'-sulfolacto-N-fucopentaose III (sulfo-3Galbeta1-4(Fucalpha1-3)GlcNAcbeta1-3Galbeta1-4Glc)-PA was then synthesized from lacto-N-neotetraose (Galbeta1-4GlcNAcbeta1-3Galbeta1-4Glc)-PA by GP3ST and FucT-III, -IV, -V, -VI, -VII, or -IX in a similar manner. The substrate specificity for the 3'-sulfated acceptor of the alpha1,3-fucosyltransferases was considerably different from that for the non-substituted and 3'-sialylated varieties. When the GP3ST gene was introduced into A549 and Chinese hamster ovary cells expressing FucT-III, they began to express 3'-sulfo-Le(a) and 3'-sulfo-Le(x) epitopes, respectively, suggesting that GP3ST is responsible for their biosynthesis in vivo. The expression of the 3'-sialyl-Le(x) epitope on Chinese hamster ovary cells was attenuated by the introduction of GP3ST gene, indicating that GP3ST and alpha2,3-sialyltransferase compete for the common Galbeta1-4GlcNAc-R oligosaccharides. Last, arylsulfatase A, which is a lysosomal hydrolase that catalyzes the desulfation of 3-O-sulfogalactosyl residues in glycolipids, was found to hydrolyze the sulfate ester bond on the 3'-sulfo-Le(x) (type 2 chain) but not that on the 3'-sulfo-Le(a) (type 1 chain). The present remodeling system might be of potential use as a tool for the study of the physiological roles of 3'-sulfated Lewis epitopes, including interaction with selectins.

Animals↗