Biomedical subjects

Y Ueno

Publications and source records attributed to Y Ueno.

At least 127 records · Page 7Linked to original sources

PubMed2000

Assessment of regional cerebral blood flow by xenon-enhanced computed tomography during mastication in humans.

It is suggested that mastication stimulates the brain and accelerates its energy-consuming metabolism. This study was designed to determine its effects on regional cerebral blood flow (rCBF) using xenon-enhanced computed tomography (Xe-CT). Seven male volunteers, aged 24-57 years, inhaled 30% xenon in a 4 minutes wash-in and 4 minutes wash-out protocol. CT was scanned every 54.5 seconds. The subjects were instructed to chew a gum continuously at a rate of 1 bite per second except at the time of CT scanning (5.5 seconds). A second CBF was done 20 minutes later. Subtraction (mastication-baseline) maps were created. CT images were taken at three levels so as to include the cortex, basal ganglia, limbic system, brainstem and cerebellum. The results demonstrated a significant rCBF increase in the fronto-temporal cortex, caudate nucleus, thalamus and minor increase in the rolandic areas, insula, cingulate and cerebellum. Further studies are needed to validate the clinical significance of these findings.

Adult↗

PubMed2000

[A case of infected renal cyst extending to leg abscess].

A 45-year-old woman was referred to our hospital with the chief complaint of left flank pain, left leg pain and loss of appetite. Computed tomography scan and magnetic resonance imaging demonstrated a large cystic mass in the left kidney, which we diagnosed as an infected renal cyst. Under ultrasonic guidance, percutaneous puncture and drainage of the renal cyst were performed. After her leg pain worsened, computed tomography revealed abscesses in the left leg, suggesting an infected renal cyst extending to the leg through the obturator foramen. Under general anesthesia, incision and drainage were performed. Cultures from the cyst and abscess fluid showed Klebsiella pneumoniae. Our case is the 82nd case of an infected renal cyst in the Japanese literature.

Abscess↗

PubMed2000

[The use of a modified vertical mandibular osteotomy for exposure of a distal cervical internal carotid artery].

We report herein the case of a 56-year-old woman who presented with repeated transient ischemic attacks (TIAs). Cerebral angiography revealed that the left redundant internal carotid artery (ICA) uncharacteristically curved medially. These findings were highly suggestive of an internal carotid artery aneurysm at the level between the first and second cervical vertebral bodies. The lesion was presumed to be difficult to access by the surgical procedure usually adopted in carotid endarterectomy. Thus, we decided to employ a modified vertical mandibular osteotomy. The operative view revealed that the lesion was atherosclerotic stenosis with ulceration, so carotid endarterectomy was indicated. This mandibular osteotomy not only provided us with wide, satisfactory exposure of the distal cervical internal carotid artery but also afforded good mandibular stability during the postoperative period.

Carotid Artery Diseases↗

PubMed2000

Identification of 7-hydroperoxycholesterol in human liver by liquid chromatography-mass spectrometry.

BACKGROUND: A liquid chromatography-mass spectrometry with an atmospheric chemical ionization interface has been developed to identify simultaneously various oxygenated cholesterols in lipid extracts from alcoholic fatty liver. METHODS: We collected human liver tissues from alcoholic and control subjects at autopsy. We purified the lipid extracts with solid phase extraction and injected them onto a spherisorb ODS column, by using methanol that contained 10 mM ammonium acetate as a mobile phase and a flow rate of 0.7 ml/min. RESULTS: We found the presence of 7-hydroperoxycholesterol and other oxysterols (5-cholesten-3beta-ol-7-one, cholest-5-ene-3beta, 7-diol, and 5, 6beta-epoxy-5beta-cholestan-3beta-ol) in alcoholic fatty liver tissues. CONCLUSIONS: We assume that long-term ethanol ingestion leads to excessive oxidative stress and to the accumulation of cholesterol-derived hydroperoxides and oxysterols in alcoholic fatty liver.

Adult↗

PubMed2000

7alpha- and 7beta-hydroperoxycholest-5-en-3beta-ol in muscle as indices of oxidative stress: response to ethanol dosage in rats.

BACKGROUND: Alcohol-induced muscle disease (AIMD) encompasses both acute and chronic lesions, and affected patients exhibit concomitant functional and structural lesions. The pathogenic mechanisms are unknown, although it is possible that defects in the membrane-lipid domain are involved. Therefore, the effect of acute ethanol on membrane lipid from rat skeletal muscles (control, n = 7; ethanol, n = 7) was investigated. METHODS: Soleus and plantaris skeletal muscles were collected 24 hr after a single dose of 75 mmol/kg of ethanol. Lipids were analyzed by high-performance liquid chromatography with postcolumn chemiluminescence. RESULTS: We found that two cholesterol-derived hydroperoxides, 7alpha-hydroperoxycholest-5-en-3beta-ol (7alpha-OOH) and 7beta-hydroperoxycholest-5-en-3beta-ol (7beta-OOH) were present in soleus muscles of control animals (1.29 nmol/g and 3.20 nmol/g, respectively) and in plantaris (1.83 and 5.18 nmol/g, respectively). These hydroperoxides were significantly elevated by acute ethanol, in not only plantaris but also soleus skeletal muscle of rats. In contrast, protein carbonyl concentration, another indicator of oxidative stress, albeit to proteins, was not significantly affected in either soleus or plantaris muscles of ethanol dosed rats. In addition, gas chromatographic study of fatty acid composition from phospholipid of rat muscle showed a significant increase of 18:2 by ethanol in plantaris as well as soleus. Concomitant decreases occurred in the nonessential/essential fatty acid ratios. CONCLUSIONS: This is the first report on 7alpha-OOH and 7beta-OOH accumulation in rat skeletal muscle, and it seems to reflect greater oxidative stress in the pathology of muscle of rats treated with acute ethanol. Together with the elevation of 18:2, these results signify perturbations in membrane lipids in response to ethanol, which may have important implications for the pathogenesis of alcohol-induced muscle disorders.

Animals↗

PubMed2000

[Positive rate of anti-mitochondrial antibody in Japanese corporate workers].

Anti-mitochondrial antibody(AMA) has been reported to be detectable in approximately 85% of patients with primary biliary cirrhosis(PBC). Therefore, a test for AMA is acceptable to be essential for diagnosing PBC. However, the positive rate in Japanese general population has not yet been determined. We tested sera from 1,145 corporate workers who took an annual health check and evaluated the liver of AMA-positive subjects. An indirect immunofluorescence method was used for screening AMA. ELISA and immunoblotting method were used for detecting anti-M2 in AMA-positive cases. AMA was detected in 5 of 1,145(0.44%) corporate workers. AMA positive rate was higher in females than in males(0.91% and 0%, respectively) and the AMA-positive people are all females over age 40. All of the AMA-positive sera are also positive for Anti-M2. Liver biopsy was performed in two AMA-positive cases and the histology was compatible with PBC in both cases.

Adolescent↗

PubMed2000

Clustering and averaging of images in single-particle analysis.

Single particle analysis is a straightforward method for studying the structures of macromolecules that cannot be crystallized. It builds three-dimensional structures of particles by estimating the projection angles of their randomly oriented electron-microscopic images. The existing methods divide the images into clusters, build class averages for the clusters, and estimate the projection angle of each cluster. However, the clustering and the averaged images are highly sensitive to the choice of reference images and mask patterns for each cluster. Thus, the analyses are neither robust nor automatic, and their results depend heavily on the intuition and experience of researchers who set references. We have been developing a software system for single-particle analysis with new clustering and averaging algorithms for building the three-dimensional structures of target molecules. In this paper, we focus on the algorithms for the robust image-processing of the electron microscopic images in our system.

Algorithms↗

PubMed1999

Crystallographic studies on damaged DNAs. I. An N(6)-methoxyadenine residue forms a Watson-Crick pair with a cytosine residue in a B-DNA duplex.

Oxyamines such as hydroxylamine and methoxylamine disturb DNA replication and act as potent mutagens, causing nucleotide transition from one purine to another or one pyrimidine to another. In order to investigate mismatch base-pairing in DNA damaged with oxyamines, a dodecamer with the sequence d(CGCGmo(6)AATCCGCG), where mo(6) A is 2'-deoxy-N(6)-methoxyadenosine, was synthesized and its crystal structure determined. No significant conformational changes are found between the present dodecamer and the original undamaged B-form dodecamer. Electron density maps clearly show that the mo(6)A residue forms a base-pair with a 2'-deoxycytidine residue through hydrogen bonds similar to a Watson-Crick G.C base-pair. For these hydrogen bonds to be made, N(6)-methoxyadenine must chemically take the imino form. The methoxylation thus enables the adenine base to mimic a guanine base. As a result, misincorporation of 2'-deoxycytidine instead of thymidine, or 2'-deoxyadenosine instead of 2'-deoxyguanosine, can occur in DNA replication.

Adenine↗

PubMed1999

Crystallographic studies on damaged DNAs. II. N(6)-methoxyadenine can present two alternate faces for Watson-Crick base-pairing, leading to pyrimidine transition mutagenesis.

In a previous paper, 2'-deoxy-N(6)-methoxyadenosine (mo(6)A) was shown to form a mismatch base-pair with 2'-deoxycytidine with a Watson-Crick-type geometry. To fully understand the structural basis of genetic mutations with damaged DNA, it is necessary to examine whether the methoxylated adenine residue still has the ability to form the regular Watson-Crick pairing with a thymine residue. Therefore, a DNA dodecamer with the sequence d(CGCGmo(6)AATTCGCG) has been synthesized and its crystal structure determined. The methoxylation has no significant effect on the overall DNA conformation, which is that of a standard B-form duplex. The methoxylated adenine moieties adopt the amino tautomer with an anti conformation around the C(6)-N(6) bond to the N(1) atom, and they form a Watson-Crick base-pair with thymine residues on the opposite strand, similar to an unmodified adenine residue. It is concluded that methoxylated adenine can present two alternate faces for base-pairing, thanks to the amino<-->imino tautomerism allowed by methoxylation. Based on this property, two gene transition routes are proposed.

Adenine↗

PubMed1999

Formation of 5-formyl-2'-deoxycytidine from 5-methyl-2'-deoxycytidine in duplex DNA by Fenton-type reactions and gamma-irradiation.

5-methyl-2'-deoxycytidine (5-Me-dC) is formed by the enzymatic methylation of dC, primarily in CpG sequences in DNA, and is involved in the regulation of gene expression. In the present study, 5-Me-dC and double-stranded DNA fragments containing 5-Me-dC were either gamma-irradiated or aerobically treated with Fenton-type reagents, Fe(II)-EDTA, Fe(II)-nitrilotriacetic acid, Fe(III)-EDTA-H(2)O(2)-catechol or ascorbic acid-H(2)O(2) under neutral conditions. The formation of 5-formyl-2'-deoxycytidine (5-CHO-dC) was observed upon treatment of both 5-Me-dC and DNA fragments containing 5-Me-dC. The yields of 5-CHO-dC from 5-Me-dC and those of 5-formyl-2'-deoxyuridine from dT were comparable. These results suggest that 5-Me-dC in DNA is as susceptible to oxidation as dT in cells, and raise the possibility that 5-CHO-dC may contribute to the high mutagenic rate observed in CpG sequences in genomic DNA.

Ascorbic Acid↗

PubMed1999

Lysophosphatidylcholine phosphorylates CREB and activates the jun2TRE site of c-jun promoter in vascular endothelial cells.

Lysophosphatidylcholine (lyso-PC), a polar phospholipid increased in atherogenic lipoproteins and atherosclerotic lesions, has been shown to induce transcription of a variety of endothelial genes relevant to atherogenesis. Lyso-PC has been shown to activate c-jun N-terminal kinase (JNK) and activator protein 1 (AP-1) and thereby stimulate transcription of the c-jun gene. Here we provide evidence that lyso-PC can phosphorylate cyclic AMP responsive element binding protein (CREB) and thereby activate the jun2 12-O-tetradecanoylphorbol 13-acetate response element (jun2TRE) site of the c-jun promoter, which appears to be the major molecular mechanism involved in lyso-PC-induced c-jun gene expression in cultured bovine aortic endothelial cells (BAEC). Transient transfection of BAEC with a 1.6-kbp c-jun promoter and luciferase reporter fusion gene resulted in a 12.9-fold increase in luciferase activity by lyso-PC treatment. Serial deletion mutation in c-jun promoter and luciferase reporter gene assay revealed that the 5' promoter region between nucleotide numbers -268 and -127, which contains a jun2TRE binding sequence, was most crucial for lyso-PC-induced transcription. The 5' promoter region between -76 and -27, which contains an AP-1 site, also affected lyso-PC-induced transcription of the c-jun gene. Point mutation in the jun2TRE site reduced lyso-PC-induced transcription of the c-jun promoter-luciferase fusion gene by a 70.3% decrease in c-jun promoter activity. Electrophoretic mobility shift assays showed increased binding of (32)P-labeled oligonucleotides with jun2TRE in nuclear extracts isolated from lyso-PC-treated BAEC, which was abolished or supershifted by anti-CREB antibody. Immunoblotting with anti-phosphorylated CREB antibody showed rapid phosphorylation of this protein after lyso-PC treatment. These results indicate that lyso-PC phosphorylates CREB, which was then bound to the jun2TRE site of the c-jun promoter and activated transcription. Activation of jun2TRE may play a key role in the transcriptional activation of c-jun as well as other endothelial genes depending upon these transcription factors.

Animals↗

PubMed1999

Calcitonin is a major regulator for the expression of renal 25-hydroxyvitamin D3-1alpha-hydroxylase gene in normocalcemic rats.

Regulation of vitamin D metabolism has long been examined by using vitamin D-deficient hypocalcemic animals. We previously reported that, in a rat model of chronic hyperparathyroidism, expression of 25-hydroxyvitamin D3-1alpha-hydroxylase (CYP27B1) mRNA was markedly increased in renal proximal convoluted tubules. It is believed that the major regulator for the expression of renal CYP27B1 is parathyroid hormone (PTH). However, in the normocalcemic state, the mechanism to regulate the renal CYP27B1 gene could be different, since plasma levels of PTH are very low. In the present study, the effect of PTH and calcitonin (CT) on the expression of renal CYP27B1 mRNA was investigated in normocalcemic sham-operated rats and normocalcemic thyroparathyroidectomized (TPTX) rats generated by either PTH or CaCl2 infusion. A single injection of CT dose-dependently decreased the expression of vitamin D receptor mRNA in the kidney of normocalcemic sham-TPTX rats. Concomitantly, CT greatly increased the expression of CYP27B1 mRNA in the kidney of normocalcemic sham-TPTX rats. CT also increased the expression of CYP27B1 mRNA in the kidney of normocalcemic TPTX rats. Conversion of serum [3H]1alpha,25(OH)2D3 from 25-hydroxy[3H]vitamin D3 in vivo was also greatly increased by the injection of CT into sham-TPTX rats and normocalcemic TPTX rats, but not into hypocalcemic TPTX rats. In contrast, administration of PTH did not induce the expression of CYP27B1 mRNA in the kidney of vitamin D-replete sham-TPTX rats and hypocalcemic TPTX rats. PTH increased the expression of renal CYP27B1 mRNA only in vitamin D-deficient hypocalcemic TPTX rats. These results suggest that CT plays an important role in the maintenance of serum 1alpha,25(OH)2D3 under normocalcemic physiological conditions, at least in rats.

25-Hydroxyvitamin D3 1-alpha-Hydroxylase↗

PubMed1999

An unusual case of suicide by stabbing with a falling weighted dagger.

An unusual suicide by self-stabbing is presented. A 42-year-old man committed suicide with a dagger weighted with 2.72 kg in total and allowed to fall freely. The blade of the dagger fell from a height of 10 cm above the chest, penetrated the second left intercostal skin and pierced the upper lobe of the left lung. However, the weapon did not penetrate the chest skin from a stationary position in our trial at the autopsy. This finding confirms the results of experiments with stab wound dynamics which demonstrated that the impact velocity of the weapon as well as the sharpness of the tip is important for skin penetration.

Adult↗

PubMed1999

Purification and characterization of hydrogenase from the marine green alga, Chlorococcum littorale.

Hydrogenase from the marine green alga, Chlorococcum littorale, was purified 1485-fold, resulting in a specific activity for hydrogen evolution of 75.7 micromol/min/mg of protein at 25 degrees C, using reduced methyl viologen as an electron donor. The K(m) value for methyl viologen was 0.5 mM. The purity of the enzyme was judged by native PAGE. The molecular weight was estimated to be 55 kDa by SDS-PAGE, and 57 kDa by gel filtration. The optimum temperature and pH value for hydrogen evolution were 50 degrees C and 7.5, respectively. The partially purified hydrogenase catalyzed hydrogen evolution from ferredoxin that had been isolated from the same cells, but not from NADH or NADPH. The K(m) value for ferredoxin was 0.68 microM. The enzyme was extremely oxygen sensitive, losing over 95% of its activity upon exposure to air within minutes, even at 4 degrees C. Two peptide fragments were obtained from the hydrogenase protein digested enzymatically, and their amino acid sequences were determined. No significant homology was found to any other known sequences of hydrogenases.

Amino Acid Sequence↗

PubMed1999

Survey of microcystins in water between 1995 and 1996 in Paraná, Brazil using ELISA.

An enzyme-linked immunosorbent assay (ELISA) based on a monoclonal antibody was used to determine microcystin (MC) concentrations in water supplies and water plant samples collected between November 1995 and October 1996, from five regions of Paraná, Brazil. In addition, the presence of Microcystis sp. was monitored. Of the 50 samples obtained, 12 were from an urban lake, 8 from human water supplies, 10 from recreational lakes, 13 from farm waters used for animal pasture and 7 from aquaculture facilities. M. aeruginosa was positive in all locations. MCs were positive (>50 pg ml(-1)) in 9 samples (2 samples from human water supplies, 5 from recreational lakes and 2 from animal pasture). Heavy contamination with MCs was observed in water samples collected in May 1996 from 2 recreation (swimming-fishing sites at Itaipu dam, 6380 and 10,000 pg ml(-1)) and human supplies (6627 pg ml(-1)) samples. At these sites, a large bloom of Microcystis sp. was detected. Treatment with 1 ppm Cl- reduced MCs levels, although 267 pg ml(-1) remained in the water plant samples. Our data showed frequent occurrence of Microcystis sp., which may be a hazard to humans and animals in the state of Paraná. More detailed investigations are required to evaluate the risk of natural MC contamination in the water supplied in this region.

Bacterial Toxins↗

PubMed1999

Immunohistochemistry of fumonisin in poultry using avidin-biotin-peroxidase system.

Using monoclonal anti-fumonisin B1 antibody (anti-FB1) and avidin-biotin-peroxidase system, liver and kidneys of broiler chicks were evaluated for the detection and distribution of fumonisins (FBs). One hundred and fifty micrograms of FB1 or culture extract of Fusarium moniliforme str. 113F containing 150 microg of FB1 and 4 microg of FB2 were administered into the vitelline sac of 1-day old, specific pathogen-free chicks. The animals were killed 24 h after injection, and renal and hepatic tissues submitted for immunohistochemical analysis. FBs were detected in the epithelial cells of convoluted distal and proximal tubules of the kidneys, as well as in the cytoplasm of hepatocytes. This novel immunohistochemical method developed is expected to be an efficient way for monitoring the target of the FB toxins in tissues.

Animals↗

PubMed1999

Mucosal IL-7-mediated immune responses in chronic colitis-IL-7 transgenic mouse model.

We have demonstrated that intestinal epithelial cells produce interleukin-7 (IL-7) and IL-7 serves as a regulatory factor for proliferation of mucosal lymphocytes. To clarify the mechanism by which locally produced IL-7 regulates mucosal lymphocytes and the role of mucosal IL-7 in colonic inflammation, we investigated IL-7 transgenic (IL-7 Tg) mice and demonstrated that IL-7 Tg mice developed acute and chronic colitis with histopathological similarity to ulcerative colitis in humans. In concert with our recent findings that IL-7 stimulates the proliferation of inactivated mucosal lymphocytes but eliminates activated lymphocytes in the inflamed mucosa of human ulcerative colitis. These findings suggest that chronic inflammation in the colonic mucosa is mediated by dysregulation of epithelial cell-derived IL-7 system.

Animals↗

PubMed1999

Cholesterol-derived hydroperoxides in alcoholic liver disease.

Human liver samples from 33 patients were collected at autopsy (controls, n = 9; fatty liver, n = 12; liver cirrhosis, n = 12), and samples homogenized. Lipids extracted with chloroform and methanol were injected into the octyl column of a high-performance liquid chromatograph with post-column chemiluminescence. Liquid chromatography-mass spectrometry was developed to identify 7-hydroperoxycholest-5-en-3 beta-ol (7-OOH). We found that two cholesterol-derived hydroperoxides, 7 alpha-hydroperoxycholest-5-en-3 beta-ol (7 alpha-OOH) and 7 beta-hydroperoxycholest-5-en-3 beta-ol (7 beta-OOH), are present in significantly elevated amounts (12.4 and 25.0 nmol/g tissue, respectively) in lipid extracts from alcoholic fatty liver, but not in extracts from alcoholic cirrhotic liver. 7 alpha-OOH and 7 beta-OOH are early intermediates produced during free radical-mediated cholesterol oxidation and can serve as molecular indicators of chain peroxidative damage in cell membranes. This is the first demonstration of 7 alpha-OOH and 7 beta-OOH accumulations in human liver, and it is presumed to reflect greater oxidative stress pathology in alcoholic fatty liver.

Adult↗