Search PubMed⌕ Search

Biomedical subjects

Y Murata

Publications and source records attributed to Y Murata.

At least 145 records · Page 8Linked to original sources
PubMed2000

APCL, a central nervous system-specific homologue of adenomatous polyposis coli tumor suppressor, binds to p53-binding protein 2 and translocates it to the perinucleus.

APCL, a central nervous system-specific sequence homologue of the adenomatous polyposis coli tumor suppressor, can regulate the cytoplasmic level of beta-catenin as the adenomatous polyposis coli tumor suppressor does, but its overall biological function remains unclear. Using a yeast two-hybrid system, we attempted to isolate proteins that might associate with the unique COOH-terminus of APCL. Among 166 cDNA clones isolated from a human fetal-brain cDNA library as candidates for interaction with APCL, 32 encoded parts of p53-binding protein 2 (53BP2), a molecule that interacts with p53 and Bcl2. An in vitro binding assay indicated that the Src-homology-3 domain and the ankyrin-repeat domain of 53BP2 were both required for binding to the COOH-terminus of APCL. Confocal microscopy showed that APCL and 53BP2 proteins were localized together in the perinuclei of normal mammalian cells, but this was not the case in cells that expressed truncated APCL and 53BP2 proteins. These findings suggested that binding of the COOH-terminus of APCL to 53BP2 regulates the cytoplasmic location of 53BP2. Because 53BP2 also interacts with p53 and Bcl2 and regulates p53 function, our results suggest that APCL might be involved in the p53/Bcl2-linked pathway of cell-cycle progression and cell death.

Adenomatous Polyposis Coli Protein↗
PubMed2000

Isolation and characterization of a novel TP53-inducible gene, TP53TG5, which suppresses growth and shows cell cycle-dependent transition of expression.

Through a strategy of direct cloning of TP53-binding DNA sequences from human genome DNA, we have identified a novel TP53-target gene, termed TP53TG5 (TP53-target gene 5). This gene, localized to chromosome band 20q13.1 by fluorescence in situ hybridization, encodes a 290-amino-acid peptide with no significant homology with any known proteins in the public database. A colony-formation assay using human glioblastoma cell line T98G, which lacks wild-type TP53 and expresses no endogenous TP53TG5, revealed a growth-suppressive effect of the TP53TG5 gene product. Furthermore, immunohistochemical studies, following transfection of T98G with plasmid designed to express green fluorescent protein-fused TP53TG5, revealed cell cycle-dependent intracellular localization of this protein. Our results suggest that functional studies of TP53TG5 may provide new insights into the complex physiological activities of TP53.

Adaptor Proteins, Signal Transducing↗
PubMed2000

Voltage-gated K(+)Channel, Kv4.2, localizes predominantly to the transverse-axial tubular system of the rat myocyte.

Kv4.2 subunit, a member of K(+)channel gene family, is considered to play a major role in the formation of depolarization-activated transient outward K(+)current channels in the mammalian heart. We investigated the subcellular localization of Kv4.2 subunit in the rat heart by immunofluorescence and immunoelectron microscopy. In atrial cells, Kv4.2 immunofluorescent staining was intensely observed in the peripheral sarcolemma and the intercalated disks, but seldom found in transverse tubules, which are rare or absent in atrial cells. In ventricular cells, the labeling of Kv4.2 immunofluorescent staining was found throughout the entire cell membrane, and the staining was stronger in the transverse-axial tubular system than in the peripheral sarcolemma. Correlative immunoconfocal and immunoelectron microscopy using FluoroNanogold confirmed that Kv4.2 distributed in the transverse-axial tubular system including the longitudinally oriented axial tubules. Immunogold electron microscopy of ultrathin cryosections revealed that Kv4.2 was distributed on the plasma membranes of the T-tubules. The extensive distribution of Kv4.2 on the entire cell membrane of myocytes would provide rat myocardial cells with a large capability for the transport of K(+)ions through the channels in the repolarization phase.

Animals↗
PubMed2000

Identification of a novel myosin-Va mutation in an ataxic mutant rat, dilute-opisthotonus.

Mutations of the myosin-Va gene (Myo5a) cause diluted coat color in mice and are occasionally associated with severe neurological disorders. Dilute-opisthotonus (dop) is a spontaneous gene mutation in the rat, and phenotypes of the homozygote (dop/dop) are similar to those of the Myo5a-deficient mouse, suggesting that the mutation resides in the rat Myo5a gene. To elucidate the molecular basis of the dop mutation, we cloned the rat Myo5a cDNA from the wild type and the dop/dop. The wild-type rat Myo5a cDNA contained a 5487-bp ORF and showed higher homology with Myo5a of the other species than Myr6 (Myo5b) in the rat. A 141-bp in-frame deletion was detected in the head region in the dop cDNA. An intragenic rearrangement consisting of a 306-bp inversion associated with 17-bp and 217-bp deletions were identified in the Myo5a gene of the dop genome. This rearrangement involved a 141-bp exon, which was skipped in the dop transcript. The MyoVA protein expression was severely impaired in the dop/dop brain. This is the first report to define the dop mutation as the Myo5a gene abnormality in the rat.

Amino Acid Sequence↗
PubMed2000

Autofluorescence in indomethacin-induced gastric mucosal lesions in rats.

Autofluorescence observations enable scientists to sensitively identify various lesions. Non-steroidal anti-inflammatory drugs such as aspirin and indomethacin are well known to induce gastric mucosal injuries. Our purpose was to clarify whether the observation of mucosal autofluorescence could help us to recognize indomethacin-induced gastric lesion formation. Gastric mucosal fluorescence intensity and gastric lesion scores were time-sequentially measured after indomethacin treatment in rats. To identify the localization of autofluorescent substances, stomach cryosections were observed with an epifluorescence microscope. Fluorescent substances from damaged tissue were also analyzed by high-performance liquid chromatography. In addition, to elucidate whether oxidative stress directly generates fluorescent substances from heme, we investigated the reaction between hydrogen peroxide and hemoglobin in a cell-free system. Treatment with indomethacin induced gastric lesions by tissue peroxidation, with mucosal fluorescence intensity increasing time-dependently. The fluorescence products were mesoporphyrin and protoporphyrin, and they were localized in disrupted mucosal tissue. In the cell-free system, porphyrins were directly generated by hydrogen peroxide from hemoglobin. These findings indicate that indomethacin treatment increased the intensity of porphyrin fluorescence. Gastric mucosal lesion formation can be sensitively detected with fluorescence observations.

Animals↗
PubMed2000

Histologic and biochemical study of the brain, heart, kidney, and liver in asphyxia caused by occlusion of the umbilical cord in near-term fetal lambs.

OBJECTIVE: We sought to determine the relationship between the degree of histologic changes in the brain, heart, kidney, and liver in fetal lambs after severe asphyxia and to analyze the role of oxidative stress in the pathogenesis of fetal multiple organ failure. STUDY DESIGN: Eight chronically instrumented near-term fetal lambs were asphyxiated by partial umbilical cord occlusion for approximately 60 minutes until the fetal arterial pH reached <6.9 and the base excess reached <-20 mEq/L. An additional 6 fetuses were used as sham-asphyxiated controls. Fetal heart rates, blood pressure, fetal breathing movements, and arterial blood gases and acid-base states were serially monitored. The brain, heart, kidney, and liver were collected 72 hours after asphyxia, processed, and histologically examined after hematoxylin and eosin staining. Fetal brain histologic features were classified into 5 grades, with 5 being the most severe damage. The other organs were examined histologically by pathologists who were blinded to the treatment. Each organ was assayed for tissue concentrations of thiobarbituric acid-reactive substances, superoxide dismutase, glutathione, lactate, and glucose. RESULTS: Myocardial changes of necrosis, phagocytosis, and contraction bands occurred in only 2 of the most severely (grade 5) brain-damaged fetuses. The same 2 cases showed fatty changes and congestion in the liver. In the kidney all asphyxiated cases showed tubular necrosis, but glomeruli were generally spared. Of the measures of oxidative stress, only liver tissue levels of thiobarbituric acid-reactive substances and superoxide dismutase were significantly higher in the asphyxiated group than in the control group, but there was no correlation with the degree of damage. Lactate level was higher only in the heart in the asphyxiated fetuses. CONCLUSION: Renal tubular damage was seen with all degrees of asphyxia, despite variable brain damage. Histologic changes in the myocardium and liver were seen only with the most severe brain damage. Oxidative stress appears to play a role in the pathogenesis of liver damage.

Animals↗
PubMed2000

Susac syndrome.

PURPOSE: To report the first Japanese case of the Susac syndrome characterized by microangiopathy of the brain, retina, and cochlea. METHODS: Case report. A 36-year-old Japanese man underwent extensive clinical and laboratory examination for encephalopathy, bilateral recurrent branch retinal arterial occlusion, and hearing loss. RESULTS: This case was initially diagnosed as acute disseminated encephalomyelitis. Despite exhaustive clinical and laboratory examination of the patient, no evidence of a known systemic disease was found. The bilateral recurrent branch retinal arterial occlusions were widely disseminated. Remission occurred 1 year after symptom onset. This patient demonstrated all of the clinical features associated with the Susac syndrome. CONCLUSION: Susac syndrome has been considered rare, but it is probably more common than previously thought and seems to occur in any race. This disorder usually occurs in young women, but it can affect men.

Adult↗
PubMed2000

Effect of infusion air pressure on visual field defects after macular hole surgery.

PURPOSE: A defect in the visual field is one of the serious complications of macular hole surgery. We investigated the relationship between the occurrence of visual field defect and the location of infusion cannula and air pressure during fluid-air exchange. METHODS: We studied 100 eyes from 90 patients with macular holes. All patients underwent preoperative and postoperative visual field testing. Vitreous surgery was performed in a standard three-port fashion, with surgically induced posterior vitreous detachment, fluid-air exchange, and sulfur hexafluoride gas injection. We analyzed differences in surgical methods in three groups. In group A, the infusion cannula was placed inferotemporally, and the air pressure was set at 50 mm Hg. In group B, the infusion cannula was placed inferonasally, and the air pressure was set at 50 mm Hg. In group C, the infusion cannula was placed inferotemporally, and the air pressure was set at 30 mm Hg. RESULTS: Eighteen eyes (18%) showed visual field defects after vitrectomy. The defect was always located contralateral to the infusion cannula. There was no statistically significant difference in the incidence of visual field defects in groups A and B. Decreased air pressure reduced the occurrence of visual field defects significantly (24% in group A versus 4% in group C, P = .011). CONCLUSIONS: The location of the visual field defect correlated with the location of the infusion cannula. The incidence of this visual field defect was influenced strongly by the infusion air pressure. The visual field defect may be caused by the mechanical damage of air infusion.

Aged↗
PubMed2000

Treatment of endometriosis with a decreasing dosage of a gonadotropin-releasing hormone agonist (nafarelin): a pilot study with low-dose agonist therapy ("draw-back" therapy).

OBJECTIVE: To evaluate the efficacy of half-dose GnRH agonist therapy for endometriosis. DESIGN: Prospective, longitudinal pilot study. SETTING: Osaka University Hospital. PATIENT(S): Patients with symptomatic endometriosis. INTERVENTION(S): Fifteen patients were randomized to receive either full-dose nafarelin treatment (200 microgram b.i.d.) for 24 weeks (n = 7) or full-dose nafarelin treatment for 4 weeks followed by half-dose nafarelin treatment (200 microgram daily) for 20 weeks (n = 8). MAIN OUTCOME MEASURE(S): Clinical symptoms and the results of physical examinations. Serum E(2) and carcinoma antigen 125 (CA125) levels, lipid profiles, and urinary levels of the N-telopeptide of type I collagen. Bone mineral density of the lumbar spine. RESULT(S): Subjective and objective manifestations of endometriosis were decreased to a similar extent in both study groups. Adverse effects were markedly reduced with half-dose administration. In the half-dose group, the mean serum E(2) level was significantly suppressed by 4 weeks of treatment with full-dose nafarelin and remained at approximately 30 pg/mL with half-dose nafarelin. Loss of bone mineral density was significantly less with half-dose treatment. CONCLUSION(S): Half-dose administration of nafarelin after pituitary down-regulation with full-dose nafarelin ("draw-back" therapy) is a new protocol for the treatment of endometriosis that is effective and associated with fewer adverse effects.

Administration, Intranasal↗
PubMed2000

Neonatal capsaicin treatment decreased substance P receptor immunoreactivity in lamina III neurons of the dorsal horn.

Using immunohistochemistry and in situ hybridization technique, the distribution of substance P (SP) and SP receptors was studied in the dorsal horn of the rat spinal cord after neonatal capsaicin treatment. Sprague-Dawley rats administered 100 mg/kg of capsaicin subcutaneously within 24 h after birth were examined at 8 weeks of age. In the capsaicin administered rats, slight reduction of SP immunoreactivities in lamina I, and severe decrease in lamina II were observed. In the control group, SP receptor-mRNA was observed in all laminae, and SP receptor-immunoreactivities were seen to be intense in laminae I and III. In contrast, in the capsaicin administered rats, the SP receptor-mRNA expression was low in laminae II-V, and SP receptor immunoreactivities decreased in laminae III-V. Furthermore, the density of the SP receptor immunoreactivities was considerably decreased in the nerve cells of lamina III. We concluded that elevation of the threshold to painful stimulation in rats was as a result of the decrease in SP immunoreactive afferent fibers in laminae I and II, decrease of the SP receptor-mRNA in the laminae II-V, or the decrease in SP receptor immunoreactive neurons in laminae III-V.

Animals↗
PubMed2000

Use of floating alginate gel beads for stomach-specific drug delivery.

Two types of alginate gel beads capable of floating in the gastric cavity were prepared. The first, alginate gel bead containing vegetable oil (ALGO), is a hydrogel bead and its buoyancy is attributable to vegetable oil held in the alginate gel matrix. The model drug, metronidazole (MZ), contained in ALGO was released gradually into artificial gastric juice, the release rate being inversely related to the percentage of oil. The second, alginate gel bead containing chitosan (ALCS), is a dried gel bead with dispersed chitosan in the matrix. The drug-release profile was not affected by the kind of chitosan contained in ALCS. When ALCS containing MZ was administered orally to guinea pigs, it floated on the gastric juice and released the drug into the stomach. Furthermore, the concentration of MZ at the gastric mucosa after administration of ALCS was higher than that in the solution, though the MZ serum concentration was the same regardless of which type of gel was administered. These release properties of alginate gels are applicable not only for sustained release of drugs but also for targeting the gastric mucosa.

Alginates↗
PubMed2000

Isolation and structure of pulcherrimine, a novel bitter-tasting amino acid, from the sea urchin (Hemicentrotus pulcherrimus) ovaries.

A novel sulfur-containing amino acid, pulcherrimine, has been isolated as a bitter principle from ovaries of the sea urchin Hemicentrotus pulcherrimus. The structure was elucidated as 4-(2'-carboxy-2'-hydroxy-ethylthio)-2-piperidinecarboxylic acid by spectroscopic and chemical methods. Absolute stereochemistry was determined by NOE experiments and chiral HPLC analysis. Pulcherrimine exhibited bitterness with a threshold value of 0.306 mM.

Amino Acids, Sulfur↗
PubMed2000

Biochemical properties of canine serum ferritin: iron content and nonbinding to concanavalin A.

A sandwich enzyme-linked immunosorbent assay using H-subunit-rich canine heart ferritin as a standard has been developed for measuring canine serum ferritin which is H-subunit-rich. Serum ferritin concentrations in 51 normal dogs ranged from 143 to 1766 ng ml(-1), with a mean value of 479 +/- 286 (SD) ng ml(-1). Serum ferritin iron concentrations as determined by an immunoprecipitation technique ranged from 30.4 to 115.9 ng ml(-1) in 15 normal dogs with serum ferritin protein levels of 298 to 959 ng ml(-1). There was a significant linear correlation between the serum ferritin iron and protein levels (r=0.9441, P<0.001), and the mean iron/protein ratio of serum ferritin was 0.112 +/- 0.017. When canine sera were incubated with concanavalin A-Sepharose 4B, we observed the apparent binding of serum ferritin to concanavalin A. However, ferritin obtained by heat-treating the sera at pH 4.8 to remove the ferritin-binding proteins did not bind to the lectin. These results suggest that canine serum ferritin contains a considerable amount of iron but no concanavalin A-binding G subunit present in human serum ferritin.

Animals↗
PubMed2000

Placental aminopeptidase A as a possible barrier of angiotensin II between mother and fetus.

Aminopeptidase A (AP-A EC 3.4.11.7), which is a membrane-bound zinc metalloprotease, is present in the placenta. AP-A selectively hydrolyzes N-terminal glutamyl and aspartyl residues and cleaves angiotensin II to form angiotensin III. To determine the role of placental aminopeptidase A under physiological and pathological conditions, we evaluated its immunolocalization and enzymatic activities in the placenta. AP-A was localized in the basal zone of the syncytiotrophoblast, in the membranes of the cytotrophoblast, and in fetal arterioles and venules within the stem villi. AP-A activity in the microsomal fraction of placental villi seemed to be remained essentially constant throughout gestation. The renin-angiotensin system is considered to be accelerated in pre-eclampsia. This AP-A activity was higher in pre-eclampsia (2.86+/-0.30 nmol beta NA/mg protein/h) than in uncomplicated pregnancy from 28 to 41 weeks of gestation (2.08+/-0.18 nmol beta NA/mg protein/h). Angiotensin II evoked AP-A activity in first trimester trophoblast, and Losartan and PD 123177 in combination significantly inhibited this induction of AP-A activity. The results of immunohistochemical evaluation and enzymatic activity suggested that placental aminopeptidase A may play a role as a component of the barrier of angiotensin II between mother and fetus.

Adult↗
PubMed2000

Elevations of group II phospholipase A2 concentrations in serum and amniotic fluid in association with preterm labor.

OBJECTIVE: The purpose of this study was to determine whether the elevation of secretory group II phospholipase A(2) concentration in the serum and amniotic fluid in preterm labor is associated with intrauterine inflammation. STUDY DESIGN: Serum and amniotic fluid were collected from women with preterm delivery (<37 weeks' gestation; n = 38) and term delivery (n = 20). Phospholipase activity was measured with a highly sensitive system that was based on reverse-phase high-performance liquid chromatographic separation of 9-anthracenylmethyl derivatives of fatty acids released by phospholipase A(2). The concentrations of immunoreactive isozymes (group I or II) of secretory phospholipase A(2) were assayed with a radioimmunoassay kit with a monoclonal antibody against human pancreatic phospholipase A(2) and splenic IIA phospholipase A(2). Localization of immunoreactive group II phospholipase A(2) in the amniotic membrane was determined by immunostaining visualized with the Vectastain ABC (Vector Laboratories, Inc, Burlingame, Calif) method. RESULTS: Enzymatic activities of phospholipase A(2) in the serum and amniotic fluid specimens obtained from patients in preterm labor with chorioamnionitis were significantly higher than those in specimens from patients in term labor. Significant elevations of phospholipase A(2) activities were observed in patients with preterm labor without histologically evident chorioamnionitis. The activity of phospholipase A(2) was clearly correlated with the concentration of the immunoreactive group II phospholipase A(2). Group II phospholipase A(2) was localized in amniotic cells obtained from patients with a pathologically determined diagnosis of chorioamnionitis. The predictive value for chorioamnionitis of the group II phospholipase A(2) concentration was relatively higher than the predictive values of the concentrations of C-reactive protein and interleukins 6 and 8. CONCLUSION: Significant elevations of group II phospholipase A(2) concentrations were detected in the serum and amniotic fluid of women with preterm labor. Group II phospholipase A(2) concentration may be a useful indicator for preterm labor, and phospholipid metabolism is certainly activated both in preterm labor and in apparent inflammatory diseases.

Amniotic Fluid↗
PubMed2000

Immunohistochemical localization of telomerase hTERT protein and analysis of clonality in multifocal vulvar intraepithelial neoplasia.

Vulvar intraepithelial neoplasias (VINs) are potentially premalignant lesions of the squamous mucosa. The immunohistochemical distribution of the catalytic protein subunit of telomerase (hTERT) and the patterns of X chromosome inactivation were investigated as markers of neoplasia in samples from a patient with multifocal and diffuse VIN. hTERT nuclear staining in VIN correlated with squamous maturation and the degree of nuclear atypia. Normal mucosa revealed faint nuclear staining of parabasal cells and lower intermediate layer squamous cells. Monoclonal composition was demonstrated in 0 of 3 samples of VIN1, 2 of 3 samples of VIN2, and 13 of 13 samples of VIN3. The patterns of X chromosome inactivation indicated intramucosal extension and multifocal origin of individual lesions. Five samples of histologically normal vulvar squamous epithelium revealed a random pattern of X chromosome inactivation, consistent with polyclonal composition. All 19 samples from 9 lesions contained human papillomavirus (HPV)-16 sequences. Neither mutations in the p53 tumor suppressor gene or K-ras oncogenes nor loss of heterozygosity at 7 chromosomal loci were detected in any of the 19 samples of VIN. These results demonstrate that HPV-associated VIN may result from multifocal and diffuse 2-dimensional intraepithelial expansion of an immortalized monoclonal cell population.

Carcinoma in Situ↗
PubMed2000

Chorioamnionitis decreased incidence of respiratory distress syndrome by elevating fetal interleukin-6 serum concentration.

Respiratory distress syndrome (RDS) of newborns is one of the most important factors determining neonatal morbidity and mortality. The interleukin-6 (IL-6) titre in cord sera of RDS-free neonates born to mothers with histological chorioamnionitis was significantly higher than that in RDS-complicated neonates without chorioamnionitis. Maternal administration of glucocorticoid suppressed the IL-6 concentrations in the cord sera of fetuses with chorioamnionitis. The fetuses without chorioamnionitis who suffered from RDS even after maternal glucocorticoid administration showed a similar IL-6 titre to that of RDS-affected neonates without chorioamnionitis. Examination of the mechanism by which IL-6 decreased the incidence of fetal RDS revealed that H441-4, a human pulmonary adenocarcinoma cell line, stimulated with recombinant (r)-IL-6 started the synthesis of mRNA and protein of pulmonary surfactant protein (SP)-A. The present study shows that IL-6 elevation in fetuses with chorioamnionitis promotes fetal lung maturation by inducing SP-A synthesis, thereby decreasing the incidence of RDS in the preterm neonates.

Cell Line↗