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Biomedical subjects

A Itoh

Publications and source records attributed to A Itoh.

At least 37 records · Page 2Linked to original sources
PubMed2001

Difference in toxicity of beta-amyloid peptide with aging in relation to nerve growth factor content in rat brain.

Amyloid beta-peptide (Abeta) is the major constituent of the senile plaques in the brains of patients with Alzheimer's disease. We have demonstrated previously that memory impairment, dysfunction of the cholinergic and dopaminergic neuronal system and morphological degeneration are produced after the continuous infusion of Abeta into the cerebral ventricle in 8-week-old rat. In the present study, we investigated the toxicity of Abeta in infant (10 days old), adult (8 weeks old) and aged (20 months old) rats in relation to nerve growth factor (NGF) content in various regions of the brain. After a 2-week-infusion, choline acetyltransferase (ChAT) activity was significantly decreased in the hippocampus of adult, but not infant or aged rats. NGF levels in the hippocampus were increased only in adult rats. These results suggest that Abeta is toxic only in the matured adult brain, and that the mechanism of toxicity is related to NGF synthesis.

Aging↗
PubMed2001

Tetrahydroisoquinoline-monoterpene and iridoid glycosides from Alangium lamarckii.

From the water soluble fraction of the dried fruits of Alangium lamrckii, four tetrahydroisoquinoline-monoterpene glycosides, 6-O-methyl-N-deacetylisoipecosidic acid, 7-O-methyl-N-deacetylisoipecosidic acid, 6,7-di-O-methyl-N-deacetylisoipecosidic acid and 6"-O-alpha-D-glucopyranosyl-6-O-methyl-N-deacetylisoipecosidic acid, and an iridoid glycoside, 6'-O-alpha-D-glucopyranosylloganic acid, were isolated, together with six known compounds. The structures of the previously unknown compounds were determined by spectroscopic and chemical means. The significance of these glucosides in the biogenesis of Alangium alkaloids is discussed; 6-O-methyl-N-deacetylisoipecosidic acid was also chemically converted into 10-O-demethylprotoemetine and dihydroisoalangine.

Asteraceae↗
PubMed2001

Comparison of the essential oils of Glehnia littoralis from Northern and Southern Japan.

The essential oils from aerial and root parts of Glehnia littoralis were investigated by GC and GC-MS, and 125 compounds were identified. Plants were obtained from Northern and Southern Japan, and samples from the same locations were cultivated either exposed or unexposed to sunlight. The main constituents of the essential oils were found to be alpha-pinene (0.03-13.40%), limonene (0.15-10.71%), beta-phellandrene (0.03-22.93%), germacrene B (0.27-8.33%), spathulenol (0.24-6.50%), beta-oplopenone (0.06-6.47%), panaxynol (0.38-24.58%), propyl octanoate (3.44-27.85%), hexadecanoic acid (0.45-27.80%), and linoleic acid (0.16-17.56%). Terpenoid compounds were found in higher concentrations in the Northern type oils than in the Southern types, whereas the concentration of polyacetylenic compounds was higher in one of the Southern samples, except from the aerial parts of those cultivated exposed. Consequently, the constitution of the essential oils from G. littoralis could be separated into Northern and Southern types.

Apiaceae↗
PubMed2001

Smoking and drinking habits as risk factors for hearing loss in the elderly: epidemiological study of subjects undergoing routine health checks in Aichi, Japan.

In order to determine the risk factors for hearing loss in the elderly, a total of 496 subjects with bilateral hearing loss and 2807 age-matched persons without hearing disturbance were recruited from the participants in an automated multiphasic health screening examination, and their lifestyle and medical data were analysed. Current smokers showed a significantly increased risk of hearing loss compared with non-smokers (odds ratio after adjustment for sex, age, and potential confounders=2.10 (1.53-2.89)), while heavy drinkers did not show an increased risk compared to non-drinkers. Our findings might provide some clues for the primary prevention of age-related hearing loss.

Aged↗
PubMed2001

Tomato allene oxide synthase and fatty acid hydroperoxide lyase, two cytochrome P450s involved in oxylipin metabolism, are targeted to different membranes of chloroplast envelope.

Allene oxide synthase (AOS) and hydroperoxide lyase (HPL) are related cytochrome P450s that metabolize a common fatty acid hydroperoxide substrate to different classes of bioactive oxylipins within chloroplasts. Here, we report the use of in vitro import assays to investigate the targeting of tomato (Lycopersicon esculentum) AOS (LeAOS) and HPL (LeHPL) to isolated chloroplasts. LeAOS, which contains a typical N-terminal transit peptide, was targeted to the inner envelope membrane by a route that requires both ATP and proteinase-sensitive components on the surface of chloroplasts. Imported LeAOS was peripherally associated with the inner envelope; the bulk of the protein facing the stroma. LeHPL, which lacks a typical chloroplast-targeting sequence, was targeted to the outer envelope by an ATP-independent and protease-insensitive pathway. Imported LeHPL was integrated into the outer envelope with most of the protein exposed to the inter-membrane space. We conclude that LeAOS and LeHPL are routed to different envelope membranes by distinct targeting pathways. Partitioning of AOS and HPL to different envelope membranes suggests differences in the spatial organization of these two branches of oxylipin metabolism.

Aldehyde-Lyases↗
PubMed2001

Slit proteins are not dominant chemorepellents for olfactory tract and spinal motor axons.

Members of the Slit family are large extracellular glycoproteins that may function as chemorepellents in axon guidance and neuronal cell migration. Their actions are mediated through members of the Robo family that act as their receptors. In vertebrates, Slit causes chemorepulsion of embryonic olfactory tract, spinal motor, hippocampal and retinal ganglion cell axons. Since Slits are expressed in the septum and floor plate during the period when these tissues cause chemorepulsion of olfactory tract and spinal motor axons respectively, it has been proposed that Slits function as guidance cues. We have tested this hypothesis in collagen gel co-cultures using soluble Robo/Fc chimeras, as competitive inhibitors, to disrupt Slit interactions. We find that the addition of soluble Robo/Fc has no effect on chemorepulsion of olfactory tract and spinal motor axons when co-cultured with septum or floor plate respectively. Thus, we conclude that although Slits are expressed in the septum and floor plate, their proteins do not contribute to the major chemorepulsive activities emanating from these tissues which cause repulsion of olfactory tract and spinal motor axons.

Animals↗
PubMed2001

Glycosides of benzyl and salicyl alcohols from Alangium chinense.

From the water-soluble fraction of the dried leaves of Alangium chinense, three new glycosides, benzyl alcohol beta-D-glucopyranosyl-(1 --> 2)-[beta-D-xylopyranosyl-(1 --> 6)]-beta-D-glucopyranoside, 2'-O-beta-D-glucopyranosylsalicin, and 2'-O-beta-D-glucopyranosyl-6'-O-beta-D-xylopyranosylsalicin were isolated along with seven known glycosides. The structures of the new compounds were determined by spectroscopic and chemical means.

Benzyl Alcohols↗
PubMed2001

Late reperfusion (6-24 hours after onset) improves left ventricular function in patients with acute myocardial infarction.

The TAMI-6 trial has demonstrated that coronary reperfusion >6h after onset (ie, late reperfusion) in patients with acute myocardial infarction (AMI) does not improve left ventricular (LV) function during the chronic phase of infarction. However, the low patency rate (only 60%) of the infarct-related artery (IRA) during the chronic phase in the TAMI-6 trial raises a new hypothesis that late reperfusion with a higher patency rate may improve LV function during the chronic phase. Forty-four patients with AMI, who were admitted to hospital 6-24h after the symptom onset and in whom emergency coronary angiography revealed a total occlusion of the IRA, were randomly assigned to either the late reperfusion group (n=22) or the non-reperfusion group (n=22). The initial success rate of reperfusion therapy in the late reperfusion group was 86% and the chronic patency rate of the IRA was 91%. The improvements in ejection fraction and chord shortening in the infarct region from the acute phase to the chronic phase were significantly greater in the late reperfusion group than in the non-reperfusion group. Late reperfusion with a high patency rate of the IRA significantly improves LV global and regional function in patients with AMI.

Adult↗
PubMed2001

The gene polymorphism of tumor necrosis factor-beta, but not that of tumor necrosis factor-alpha, is associated with the prognosis of sarcoidosis.

OBJECTIVES: Few genetic markers for the prognosis of sarcoidosis have been found. Tumor necrosis factor (TNF)-alpha has been implicated in the pathogenesis of sarcoidosis. Induced TNF-alpha or TNF-beta levels have been shown to be associated with the polymorphisms of the TNF genes. We investigated the roles of such polymorphisms in the development and prolongation of sarcoidosis. SUBJECTS AND MEASUREMENTS: One hundred ten Japanese patients with sarcoidosis and 161 control subjects were genotyped for three biallelic polymorphisms in the promoter region of TNF-alpha gene by direct sequencing of polymerase chain reaction (PCR) products. A polymorphism of the TNF-beta gene (TNFB*1/TNFB*2) was detected by NCO: I restriction fragment length polymorphism analysis of PCR products spanning intron 1 and exon 2 of the TNF-beta gene. RESULTS: None of the polymorphisms conferred susceptibility to sarcoidosis. However, our study identified the allele TNFB*1, detected by the presence of a NCO: I restriction site, as a marker of prolonged clinical course, with the resolution of sarcoidosis being defined as the disappearance of all clinical symptoms, physical signs of active lesions, abnormal chest radiograph findings, and abnormal results of pulmonary function and biochemical tests. When the probability of remission in patients homozygous for TNFB*2 was defined as 1.00, it was 0.48 (95% confidence interval, 0.26 to 0.88; p < 0.05) in patients with TNFB*1 (genotypes TNFB*1/1 and TNFB*1/2). CONCLUSIONS: The TNFB*1 allele is a marker for prolonged clinical course in patients with sarcoidosis. Our study is the first to link a cytokine gene polymorphism to the prognosis of sarcoidosis.

Adult↗
PubMed2001

Multielement determination and speciation of major-to-trace elements in black tea leaves by ICP-AES and ICP-MS with the aid of size exclusion chromatography.

A multielement determination of major-to-trace elements in black tea leaves and their tea infusions was carried out by ICP-AES (inductively coupled plasma atomic emission spectrometry) and ICP-MS (inductively coupled plasma mass spectrometry). Tea infusions were prepared as usual tea beverage by brewing black tea leaves in boiling water for 5 min. About 40 elements in tea leaves and tea infusions could be determined over the wide concentration range in 8 orders of magnitude. The extraction efficiency of each element was estimated as the ratio of its concentration in tea infusions to that in tea leaves. From the experimental results for the extraction efficiencies, the elements in black tea leaves were classified into three characteristic groups: (i) highly-extractable elements (>55%): Na, K, Co, Ni, Rb, Cs and Tl, (ii) moderately-extractable elements (20-55%): Mg, Al, P, Mn and Zn, and (iii) poorly-extractable elements (<20%): Ca, Fe, Cu, Sr, Y, Zr, Mo, Sn, Ba and lanthanoid elements. Furthermore, speciation of major-to-trace elements in tea infusions was performed by using a combined system of size exclusion chromatography (SEC) and ICP-MS (or ICP-AES). As a result, many diverse elements were found to be present as complexes associated with large organic molecules in tea infusions.

Chromatography, Gel↗
PubMed2001

Multielement monitoring for dissolved and acid-soluble concentrations of trace metals in surface seawater along the ferry track between Osaka and Okinawa as investigated by ICP-MS.

Multielement monitoring of the concentrations of trace metals dissolved in surface seawater collected at sampling stations along the ferry track between Osaka and Okinawa was performed by ICP-MS (inductively coupled plasma mass spectrometry). The surface seawater samples were collected by an automated sampling system for on-board sampling, which was installed on the bottom of a ferryboat. A part of each seawater sample was filtered with a membrane filter (pore size of 0.45 microm) immediately after sampling. Both filtered and non-filtered seawater samples were acidified to pH ca. 1 by adding conc. HNO3, and were subjected to chelating resin preconcentration for the determination of trace metals by ICP-MS, where the concentrations of analyte metals in the filtered and non-filtered seawater samples were referred to as the dissolved and total concentrations, respectively. According to the thus-obtained results, it was found that most trace metals, especially below the 0.01 microg l(-1) as the dissolved and total concentrations, sensitively reflected the environmental pollution in the Osaka Bay and Seto Inland Sea area, as well as near to the Bungo Canal and the outlet of Kagoshima Bay.

Acids↗
PubMed2001

[Is open heart surgery clean: bacteriologic analysis of salvaged blood].

In this prospective study, we evaluated contamination of surgical fields in open heart operations by salvaged blood culture used in autologous transfusions device (Cell Saver 5, Heamonetics Corp., Braintree, MA, USA). And also, we prospectively investigated an efficacy of pre- and intra-operative prophylactic antibiotics administrations (cefazolin). Thirty patients undergone open heart surgeries with median sternotomy enrolled in this study. The patients were divided into two groups, group A (n = 15); without prophylactic antibiotics administration, group B (n = 15); with pre- and intra-operative prophylactic antibiotics administrations. Blood samples were drawn through the right atrium after the discontinuation of CPB and from salvaged blood bags. Bacterial growth was detected in 80.0% of salvaged blood samples in group A, 86.7% in group B (p = 0.62). Whereas no bacterial growth detection in blood samples though the right atrium. Quantitative estimates of contaminations showed 1.06 +/- 1.41, 0.90 +/- 1.24 cfu/ml, respectively (p = 0.22). Although bacterial growth rate were not statistically significant difference between groups, detective rate of Staphylococci was remarkably decreased (p = 0.005) in group B. Pre- and intra-operative prophylactic antibiotics administrations were effective for Staphylococci, but not whole microorganisms. In conclusion, salvaged blood used in autologous transfusions was highly contaminated and it suggests that surgical fields were not clear. Prophylactic antibiotics administrations were effective especially for Staphylococci.

Aged↗
PubMed2001

Clinical study of vestibular-evoked myogenic potentials and auditory brainstem responses in patients with brainstem lesions.

A total of 13 patients, who were diagnosed with localized brainstem lesions using MRI, were investigated. The diagnoses were multiple sclerosis in five patients, brainstem hemorrhage in three patients, pontomedullary infarction in one patient and Wallenberg's syndrome in four patients. In addition, 42 ears of 21 normal adult volunteers were also examined. In a patient with upper brainstem lesions mainly affecting the midbrain, the auditory brainstem response (ABR) was abnormal but the vestibular-evoked myogenic potential (VEMP) was normal. In four patients with middle brainstem lesions which mainly affected the pons, both ABR and VEMP were abnormal. In five patients with lower brainstem lesions which mainly affected the medulla, the ABR was normal but the VEMP was abnormal. In those patients with middle-to-lower brainstem lesions, a disappearance of VEMP reactions, delay of the positive-negative (PN) wave, increase in PN interpeak latency and decrease in PN amplitude on the affected side were confirmed. In conclusion, the VEMP test comprises a useful new diagnostic method for identifying lower brainstem lesions.

Adolescent↗
PubMed2000

Molecular cloning of a divinyl ether synthase. Identification as a CYP74 cytochrome P-450.

Lipoxygenase-derived fatty acid hydroperoxides are metabolized by CYP74 cytochrome P-450s to various oxylipins that play important roles in plant growth and development. Here, we report the characterization of a Lycopersicon esculentum (tomato) cDNA whose predicted amino acid sequence defines a previously unidentified P-450 subfamily (CYP74D). The recombinant protein, expressed in Escherichia coli, displayed spectral properties of a P-450. The enzyme efficiently metabolized 9-hydroperoxy linoleic acid and 9-hydroperoxy linolenic acid but was poorly active against the corresponding 13-hydroperoxides. Incubation of recombinant CYP74D with 9-hydroperoxy linoleic acid and 9-hydroperoxy linolenic acid yielded divinyl ether fatty acids (colneleic acid and colnelenic acid, respectively), which have been implicated as plant anti-fungal toxins. This represents the first identification of a cDNA encoding a divinyl ether synthase and establishment of the enzyme as a CYP74 P-450. Genomic DNA blot analysis revealed the existence of a single divinyl ether synthase gene located on chromosome one of tomato. In tomato seedlings, root tissue was the major site of both divinyl ether synthase mRNA accumulation and enzyme activity. These results indicate that developmental expression of the divinyl ether synthase gene is an important determinant of the tissue specific synthesis of divinyl ether oxylipins.

Amino Acid Sequence↗
PubMed2000

Neurotrophin-3 (NT-3) diminishes susceptibility of the oligodendroglial lineage to AMPA glutamate receptor-mediated excitotoxicity.

Prior reports demonstrated that cells of the oligodendroglial lineage are susceptible to excitotoxic necrosis mediated by alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid glutamate receptors (AMPA-GluR), and also showed that these cells express the high affinity neurotrophin receptors, TrkC and TrkA. We now report that: a) oligodendroglial progenitors (OP) and immature oligodendroglia are more vulnerable to AMPA-GluR-mediated excitotoxicity than are mature oligodendroglia; b) TrkC expression falls substantially during differentiation of cultured OP to mature oligodendroglia, whereas TrkA expression increases markedly; and c) neurotrophin-3, and to a lesser extent, nerve growth factor, protect the oligodendroglial lineage against AMPA-GluR-mediated excitotoxicity.

Animals↗
PubMed2000

Spatial patterns in the distribution of tropical tree species.

Fully mapped tree census plots of large area, 25 to 52 hectares, have now been completed at six different sites in tropical forests, including dry deciduous to wet evergreen forest on two continents. One of the main goals of these plots has been to evaluate spatial patterns in tropical tree populations. Here the degree of aggregation in the distribution of 1768 tree species is examined based on the average density of conspecific trees in circular neighborhoods around each tree. When all individuals larger than 1 centimeter in stem diameter were included, nearly every species was more aggregated than a random distribution. Considering only larger trees (>/= 10 centimeters in diameter), the pattern persisted, with most species being more aggregated than random. Rare species were more aggregated than common species. All six forests were very similar in all the particulars of these results.

Central America↗