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Biomedical subjects

S Ono

Publications and source records attributed to S Ono.

At least 37 records · Page 2Linked to original sources
PubMed2004

Analysis of sensitization to carboxymethylcellulose: identification of high risk group using ELISA and histamine release experiment.

OBJECTIVE AND DESIGN: Carboxymethylcellulose (CMC) has been considered to be inert and is commonly used as an additive in medicines, foods and cosmetics. However, we experienced a patient who developed an anaphylactic reaction to CMC after an upper gastrointestinal examination using a barium meal containing CMC. Therefore, we examined the incidence of sensitization by CMC in healthy subjects, and categorized the high risk group prone to developing anaphylactic response to CMC. METHODS: An ELISA for detecting CMC-specific IgE antibody was developed using serum from the patient as a positive control. In the ten subjects exhibiting high anti-CMC IgE among 387 normal populations, histamine release from isolated leukocytes was performed. RESULTS: Five of ten subjects with a high IgE titer showed a significant CMC-induced histamine release from leukocyte preparations in vitro as observed in the patient, and were classified as high risk group. There was a correlation between sensitization by CMC and that by Japanese cedar pollen. The incidence of sensitization in females was 2.4 fold higher than that in males. CONCLUSIONS: The combination of ELISA and histamine release experiment made it possible to identify the high risk group for developing anaphylactic response. The administration of high dose CMC as a suspending agent in barium sulfate or injectable corticosteroids to this group should be avoided to prevent anaphylactic reactions in the clinic.

Adult↗
PubMed2004

Local ordering in the pseudogap state of the high-Tc superconductor Bi2Sr2CaCu2O(8+delta).

We report atomic-scale characterization of the pseudogap state in a high-Tc superconductor, Bi2Sr2CaCu2O(8+delta). The electronic states at low energies within the pseudogap exhibit spatial modulations having an energy-independent incommensurate periodicity. These patterns, which are oriented along the copper-oxygen bond directions, appear to be a consequence of an electronic ordering phenomenon, the observation of which correlates with the pseudogap in the density of electronic states. Our results provide a stringent test for various ordering scenarios in the cuprates, which have been central in the debate on the nature of the pseudogap and the complex electronic phase diagram of these compounds.

Journal Article↗
PubMed2004

Dieulafoy's lesion of the esophagus correctly diagnosed and successfully treated by the endoscopic injection of N-butyl-2-cyanoacrylate.

Dieulafoy's lesion is an arterial malformation in the subumucosal layer of the gastrointestinal tract that can cause massive bleeding. The esophagus is not a common location for this lesion. We present here a first report of Dieulafoy's lesion of the esophagus correctly diagnosed and successfully treated by the endoscopic injection of N-butyl-2-cyanoacrylate.

Aged↗
PubMed2004

Intrapancreatic accessory spleen: diagnosis using contrast enhanced ultrasound.

Intrapancreatic accessory spleen (IPAS) is a mass that can mimick a neoplastic mass in the pancreas. As it poses no clinical problem no treatment is required. Unfortunately almost all the reported cases of IPAS have been misdiagnosed and unnecessary surgery performed. We performed contrast-enhanced ultrasound (CEUS) in a patient with IPAS for a research purpose, and confirmed that CEUS is useful for diagnosing this entity.

Adult↗
PubMed2003

Signature of optimal doping in Hall-effect measurements on a high-temperature superconductor.

High-temperature superconductivity is achieved by doping copper oxide insulators with charge carriers. The density of carriers in conducting materials can be determined from measurements of the Hall voltage--the voltage transverse to the flow of the electrical current that is proportional to an applied magnetic field. In common metals, this proportionality (the Hall coefficient) is robustly temperature independent. This is in marked contrast to the behaviour seen in high-temperature superconductors when in the 'normal' (resistive) state; the departure from expected behaviour is a key signature of the unconventional nature of the normal state, the origin of which remains a central controversy in condensed matter physics. Here we report the evolution of the low-temperature Hall coefficient in the normal state as the carrier density is increased, from the onset of superconductivity and beyond (where superconductivity has been suppressed by a magnetic field). Surprisingly, the Hall coefficient does not vary monotonically with doping but rather exhibits a sharp change at the optimal doping level for superconductivity. This observation supports the idea that two competing ground states underlie the high-temperature superconducting phase.

Journal Article↗
PubMed2003

The structure of nonvertebrate actin: implications for the ATP hydrolytic mechanism.

The structures of Saccharomyces cerevisiae, Dictyostelium, and Caenorhabditis elegans actin bound to gelsolin segment-1 have been solved and refined at resolutions between 1.9 and 1.75 A. These structures reveal several features relevant to the ATP hydrolytic mechanism, including identification of the nucleophilic water and the roles of Gln-137 and His-161 in positioning and activating the catalytic water, respectively. The involvement of these residues in the catalytic mechanism is consistent with yeast genetics studies. This work highlights both structural and mechanistic similarities with the small and trimeric G proteins and restricts the types of mechanisms responsible for the considerable enhancement of ATP hydrolysis associated with actin polymerization. The conservation of functionalities involved in nucleotide binding and catalysis also provide insights into the mechanistic features of members of the family of actin-related proteins.

Actins↗
PubMed2003

Intrinsic tunneling spectra of Bi2(Sr(2-x)Lax)CuO(6+delta).

We have measured intrinsic-tunneling spectra of a single CuO-layer La-doped Bi2(Sr(2-x)Lax)CuO(6+delta) (Bi2201-Lax). Despite a difference of a factor of 3 in the optimal superconducting critical temperatures for Bi2201-La0.4 and Bi2212 (32 and 95 K, respectively) and different spectral energy scales, we find that the pseudogap vanishes at a similar characteristic temperature T* approximately 230-300 K for both compounds. We find also that, in Bi2201-Lax, pseudogap humps are seen as sharp peaks and, in fact, even dominate the intrinsic spectra.

Journal Article↗
PubMed2003

Dependence of upper critical field and pairing strength on doping in cuprates.

We have determined the upper critical field Hc2 as a function of hole concentration in bismuth-based cuprates by measuring the voltage induced by vortex flow in a driving temperature gradient (the Nernst effect), in magnetic fields up to 45 tesla. We found that Hc2 decreased steeply as doping increased, in both single and bilayer cuprates. This relationship implies that the Cooper pairing potential displays a trend opposite to that of the superfluid density versus doping. The coherence length of the pairs xi(0) closely tracks the gap measured by photoemission. We discuss implications for understanding the doping dependence of the critical temperature Tc0.

Journal Article↗
PubMed2003

Histological investigations into the difference between cystic and fusiform types of congenital biliary dilatation.

We investigated the histological differences in the common bile duct wall of bile ducts with congenital biliary dilatation, examining 10 cystic types and 11 fusiform types. A flattened mucosa was found in the cystic type, and a tufted mucosa was occasionally found in the fusiform type. Glands in the choledochus wall were less common in the cystic type than in the fusiform type. Smooth muscle fibre was more abundant in the cystic type than in the fusiform type, and it was markedly developed in the distal choledochus in the cystic type. Based on these results we suggest that the developmental difference of smooth muscle fibres in the distal choledochus in the embryonic period may be closely related to the morphological difference between the cystic and fusiform types of congenital biliary dilatation.

Bile Ducts↗
PubMed2002

New insight into bile flow dynamics in anomalous arrangement of the pancreaticobiliary duct.

BACKGROUND: In an anomalous arrangement of the pancreaticobiliary duct (AAPBD), two-way regurgitation, including pancreaticobiliary reflux and biliopancreatic reflux (BPR), might occur. Although pancreaticobiliary reflux has been shown by high levels of pancreatic enzymes in bile, there have been few reports of clinical evidence of BPR in AAPBD. Recently, spiral computed tomography combined with intravenous infusion cholangiography (IVC-SCT) has been reported to be useful for visualizing the biliary anatomy, which may allow a new insight into bile flow dynamics in AAPBD. METHODS: Fifteen paediatric patients with AAPBD were examined before operation using both IVC-SCT and endoscopic retrograde cholangiopancreatography. Visualization of the main pancreatic duct on IVC-SCT defined the presence of BPR. Blood samples were also analysed when the initial symptom was strongly present. RESULTS: BPR was observed in six of 15 patients. Pancreatic enlargement and hyperamylasaemia were significantly more frequent in patients without BPR than in those with BPR. Levels of enzyme markers of cholestasis were also higher in the former group. CONCLUSION: The present study, using IVC-SCT, has identified clinical evidence of BPR in AAPBD. Further studies are necessary to determine the correlation between BPR and clinical manifestations.

Adolescent↗
PubMed2002

Acetylated histone H4 is reduced in human gastric adenomas and carcinomas.

Acetylation of core histones is closely linked to transcriptional activation of various genes. The acetylation levels of nucleosomal histones can be modified through a balance of histone acetyltransferases and deacetylases. To elucidate the role of histone acetylation in human gastric carcinogenesis, we studied the status of histone H4 acetylation in gastric carcinoma tissues and corresponding non-neoplastic mucosa. The status of histone acetylation was assessed by examining the expression of acetylated histone H4 through Western blotting and immunohistochemistry using an anti-acetylated histone H4 antibody. The levels of acetylated histone H4 expression were obviously reduced in 72% (13/18) of gastric carcinomas in comparison with non-neoplastic mucosa by Western blotting. In immunohistochemistry, acetylated histone H4 was clearly detected in the nuclei of both non-neoplastic epithelial and stromal cells, whereas the levels of acetylated histone H4 were heterogeneous or reduced in 66% (38/57) of gastric carcinomas and 46% (6/13) of gastric adenomas. Reduced expression of acetylated histone H4 was also observed in some areas of intestinal metaplasia adjacent to carcinomas. Reduction in the expression of acetylated histone H4 was significantly correlated with advanced stage, depth of tumor invasion and lymph node metastasis. These results suggest that low levels of histone acetylation may be closely associated with the development and progression of gastric carcinomas, possibly through alteration of gene expression.

Acetylation↗
PubMed2001

Grafting neural stem cells improved the impaired spatial recognition in ischemic rats.

To determine the possible therapeutic potential of neural stem cells (NSCs) introduced into the damaged central nervous system, we grafted adult hippocampus-derived NSCs into the hippocampus of rats with transient global ischemia. Transient four-vessel occlusion yielded 90-95% losses of pyramidal neurons in the hippocampal CA1 region. In this region, 1-3% of the grafted cells survived; and 3-9% of them expressed NeuN, a neuronal marker. Rats with more than 120 NeuN-positive cells showed partial improvement of impaired spatial learning in a water maze test. These results suggest that NSCs grafted in the ischemic brain are able to differentiate into neurons and to improve spatial recognition.

Animals↗
PubMed2001

Structure-activity study and analgesic efficacy of amino acid derivatives as N-type calcium channel blockers.

The synthesis and structure-activity relationship (SAR) study of a novel series of N-type calcium channel blockers are described. L-Cysteine derivative 2a was found to be a potent and selective N-type calcium channel blocker with IC(50) 0.63 microM on IMR-32 assay. Compound 2a showed analgesic efficacy in the rat formalin-induced pain model by intrathecal and oral administration.

Amino Acids↗
PubMed2001

Increased interleukin-6 of skin and serum in amyotrophic lateral sclerosis.

Studies of skin in amyotrophic lateral sclerosis (ALS) have demonstrated morphological and biochemical alterations. Interleukin-6 (IL-6) has been suggested to have a trophic effect in nerve cells and to have a direct pathogenic role in neurodegenerative central nervous system (CNS) disorders. However, little is known concerning IL-6 in ALS patients. We examined IL-6 immunoreactivity of biopsy specimens of skin and measured serum IL-6 levels from 11 ALS patients and 11 diseased control subjects. IL-6 immunoreactivity was markedly positive in the epidermis and dermal blood vessels and glands and was moderately positive in the reticular dermis in all ALS patients. These optical densities for IL-6 immunoreactivity in ALS patients were significantly higher than in control subjects, and were significantly increased with duration of illness. Serum IL-6 levels were detected in 8 (73%) of 11 ALS patients compared with only 1 (9%) of 11 diseased control subjects. Serum IL-6 levels were significantly correlated with duration of illness in ALS patients and immunoreactivity of IL-6 of the epidermis. These data suggest that the increased levels of serum IL-6 may reflect an increased IL-6 immunoreactivity of skin in ALS patients.

Adult↗
PubMed2001

Scanning tunneling spectroscopy of Bi(2)Sr(2)CuO(6+delta): new evidence for the common origin of the pseudogap and superconductivity.

Using scanning tunneling spectroscopy, we investigated the temperature dependence of the quasiparticle density of states of overdoped Bi(2)Sr(2)CuO(6+delta) between 275 mK and 82 K. Below T(c) = 10 K, the spectra show a gap with well-defined coherence peaks at +/-Delta(p) approximately 12 meV, which disappear at T(c). Above T(c), the spectra display a clear pseudogap of the same magnitude, gradually filling up and vanishing at T(*) approximately 68 K. The comparison with Bi(2)Sr(2)CaCu(2)O(8+delta) demonstrates that the pseudogap and the superconducting gap scale with each other, providing strong evidence that they have a common origin.

Journal Article↗