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Biomedical subjects

Y Oda

Publications and source records attributed to Y Oda.

At least 19 recordsLinked to original sources
PubMed2000

Crocus sativus lectin recognizes Man3GlcNAc in the N-glycan core structure.

Crocus sativus lectin (CSL) is one of the truly mannose-specific plant lectins that has a unique binding specificity that sets it apart from others. We studied sugar-binding specificity of CSL in detail by a solution phase method (fluorescence polarization) and three solid phase methods (flow injection, surface plasmon resonance, and microtiter plate), using a number of different glycopeptides and oligosaccharides. CSL binds the branched mannotriose structure in the N-glycan core. Substitution of the terminal Man in the Manalpha(1-3)Man branch with GlcNAc drastically decreases binding affinity much more than masking of the terminal Man in the Manalpha(1-6)Man branch. Most interestingly, the beta-Man-linked GlcNAc in N-glycan core structure contributes greatly to the binding. The effect of this GlcNAc is so strong that it can substantially offset the negative effect of substitution on the nonreducing terminal Man residues. On the other hand, the GlcNAc that is usually attached to Asn in N-glycans and the l-Fuc linked at the 6-position of the GlcNAc are irrelevant to the binding. A bisecting GlcNAc neither contributes to nor interferes with the binding. This unique binding specificity of CSL offers many possibilities of its use in analytical and preparative applications.

Animals↗
PubMed2000

Crystal structure of tobacco necrosis virus at 2.25 A resolution.

The crystal structure of tobacco necrosis virus (TNV) has been determined by real-space averaging with 5-fold non-crystallographic symmetry, and refined to R=25.3 % for diffraction data to 2.25 A resolution. A total of 180 subunits form a T=3 virus shell with a diameter of about 280 A and a small protrusion at the 5-fold axis. In 276 amino acid residues, the respective amino terminal 86, 87 and 56 residues of the A, B and C subunits are disordered. No density for the RNA was found. The subunits have a "jelly roll" beta-barrel structure, as have the structures of the subunits of other spherical viruses. The tertiary and quaternary structures of TNV are, in particular, similar to those of southern bean mosaic virus, although they are classified in different groups. Invisible residues 1 to 56 with a high level of basic residues are considered to be located inside the particle. Sequence comparison of the coat proteins of several TNV strains showed that the sequences of the disordered segment diverge considerably as compared with those of the ordered segment, consistent with a small tertiary structural constraint being imposed on the N-terminal segment. Basic residues are localized on the subunit interfaces or inner surface of the capsid. Positive charges of the basic residues facing the interior, as well as those of the N-terminal segment, may neutralize the negative charge of the RNA inside. Five calcium ions per icosahedral asymmetric unit are located at the subunit interfaces; three are close to the exterior surface, the other two away from it. The environments of the first three are similar, and those of the other two sites are similar. These calcium ions are assumed to be responsible for the stabilization/transition of the quaternary structure of the shell. Three peptide segments ordered only in the C subunits are clustered around each 3-fold (quasi-6-fold) axis forming a beta-annulus, and may lead to quasi-equivalent interactions for the organization of the T=3 shell.

Amino Acid Sequence↗
PubMed2000

Activation of protease-activated receptor-2 (PAR-2) triggers mucin secretion in the rat sublingual gland.

Protease-activated receptor-2 (PAR-2) is distributed throughout the gastrointestinal systems. The present study investigated the role for PAR-2 in the rat salivary glands. PAR-2 mRNA was detected in the sublingual, submaxillary, and parotid glands by a reverse-transcriptase polymerase chain reaction. In the isolated sublingual gland that exhibited the strongest signal for PAR-2, Ser-Leu-Ile-Gly-Arg-Leu-NH(2), a PAR-2-activating peptide, and trypsin, a PAR-2-activating enzyme, but not thrombin that can activate PARs 1, 3, and 4, triggered secretion of N-acetylneuraminic acid, an indicator of mucin, that was a unique major sialic acid detectable after hydrolysis of the sublingual mucin with 0.1 N HCl. The PAR-2-mediated secretion of mucin was attenuated by genistein, a tyrosine kinase inhibitor, but not by inhibitors of protein kinase C and phosphatidyl inositol 3'-kinase. Thus, PAR-2 is expressed by the three distinct salivary glands in the rat, and sublingual PAR-2 appears to play a role in triggering mucin secretion, at least in part, via activation of tyrosine kinase.

Animals↗
PubMed2000

Comparative studies on the analysis of glycosylation heterogeneity of sialic acid-containing glycoproteins using capillary electrophoresis.

Comparative studies concerning glycoform analysis of sialoglycoproteins by capillary electrophoresis were performed using a few separation modes hitherto reported. Glycoprotein samples examined in the present study were successfully separated to their respective glycoforms using surface-modified capillaries commercially available for capillary gas chromatography in the running buffer near their isoelectric points. The analysis times were less than 50 min and reproducibilities in migration times were excellent (less than 2.0% RSD for both run-to-run and day-to-day analyses). We present a method for the glycoform analysis of alpha1-acid glycoprotein in sera by simple pre-treatment as an application. The present technique will become one of the general methods for the evaluation of glycosylation heterogeneity of commercially available glycoprotein drugs.

Electrophoresis, Capillary↗
PubMed2000

The calcium sensing receptor and its alternatively spliced form in murine epidermal differentiation.

We have recently reported that human keratinocytes express both the full-length calcium sensing receptor (CaR) and an alternatively spliced form lacking exon 5, which were suggested to be involved in calcium induced keratinocyte differentiation. To understand further the role of these CaRs, we analyzed the structure of mouse CaRs, and investigated their role using a mouse model in which only the full-length CaR was disrupted. Our results show that both the full-length and the alternatively spliced variant lacking exon 5 encoding 77 amino acids of the extracellular domain were expressed in mouse epidermis. The deletion of the full-length CaR increased the production of the alternatively spliced form of CaR in mutant mice. The keratinocytes derived from these mutant mice did not respond to extracellular calcium, suggesting that the full-length CaR is required to mediate calcium signaling in the keratinocytes. The loss of the full-length CaR altered the morphologic appearance of the epidermis and resulted in a reduction of the mRNA and protein levels of the keratinocyte differentiation marker, loricrin. These results indicate that CaR is important in epidermal differentiation, and that the alternatively spliced form does not fully compensate for loss of the full-length CaR.

Alternative Splicing↗
PubMed2000

Evaluation of Epstein-Barr virus infection in sinonasal small round cell tumors.

Sinonasal undifferentiated carcinoma, olfactory neuroblastoma and malignant melanoma of the sinonasal regions are included within the category of small round cell tumors of the sinonasal region. It is difficult to diagnose these tumors on the basis of light-microscopic features alone, but, in some instances, immunohistochemical staining evaluating cytokeratin and S-100 protein, for example, is of value. On the other hand, the sinonasal region is a significant site for Epstein-Barr-virus (EBV)-related tumors, including sinonasal undifferentiated carcinoma or malignant lymphoma. Twenty-three sinonasal small round cell tumors (SSRCT) comprising 5 sinonasal undifferentiated carcinomas, 9 olfactory neuroblastomas and 9 malignant melanomas were evaluated for the presence of EBV infection by in situ hybridization for EBV-encoded RNA, combined with immunostaining for EBV-related proteins (LMP-1 and EBNA2). Furthermore, 55 SSRCT comprising 37 sinonasal undifferentiated carcinomas, 9 olfactory neuroblastomas, and 9 malignant melanomas were examined for the presence of cytokeratins (AE1/ AE3 and CAM5.2), S-100 protein and p53 protein using immunohistochemical staining. According to in situ hybridization for detecting EBV-encoded RNA 1 (EBER1), all of the sinonasal undifferentiated carcinomas showed clear, intense hybridization signals localized over the nuclei of the tumor cells and, in 3 out of 9 (33.3%) malignant melanomas, hybridization signals were also recognized. However, none of the olfactory neuroblastomas revealed hybridization signals. Immunohistochemically, 4 out of 5 (80%) sinonasal undifferentiated carcinomas were positive for LMP-1, whereas only 2 out 9 (22.2%) malignant melanomas and no olfactory neuroblastomas were positive. With regard to EBNA2, sinonasal undifferentiated carcinomas, malignant melanomas and olfactory neuroblastomas were all negative. Out of 37 sinonasal undifferentiated carcinomas 35 (94.6%) showed a diffuse positive immunoreaction for AE1/AE3, whereas neither olfactory neuroblastoma nor malignant melanoma revealed a positive reaction. All 9 malignant melanomas and 6 out of 9 olfactory neuroblastomas (75%) were positive for S-100 protein, whereas only 6 cases of sinonasal undifferentiated carcinomas (19.4%) were positive. As for p53 protein, 16 of 37 sinonasal undifferentiated carcinomas (43.2%) were positive, whereas neither olfactory neuroblastoma nor malignant melanoma revealed any positive reaction. The above results suggest that EBV infection is closely associated with sinonasal undifferentiated carcinomas, and that some malignant melanomas may also have a relationship with its infection. For the differential diagnosis of SSRCT, it is important to evaluate EBV infection along with immunohistochemical staining for cytokeratins and S-100 protein. The overexpression of p53 protein was found to be related to the oncogenesis of sinonasal undifferentiated carcinoma; however, there was no association between its overexpression and malignant melanoma or olfactory neuroblastoma.

Adult↗
PubMed2000

Nerve sheath ganglion of the ulnar nerve.

We report a case of a nerve sheath ganglion of the ulnar nerve at the canal of Guyon. This case involved a ganglion which was confined to the epineurium of the ulnar nerve. and it was completely excised without any damage to the nerve fiber. A nerve-sheath ganglion is rare, but it should be considered in the differential diagnosis of any tumor which is causing neural disturbance.

Adult↗
PubMed2000

Quantitative assessment of regional myocardial blood flow using oxygen-15-labelled water and positron emission tomography: a multicentre evaluation in Japan.

Recently, a method has been proposed for the quantitative measurement of regional myocardial blood flow (MBF) using oxygen-15-labelled water and positron emission tomography (PET). A multicentre project was organized with the intention of evaluating the accuracy of this method, particularly as a multicentre clinical investigative tool. Each of seven institutions performed PET studies on more than five normal volunteers following a specified protocol. The PET study included a transmission scan, a 15O-carbon monoxide static scan and a 15O-water dynamic scan, thereby yielding MBF values which should have been independent of the spatial resolution of the PET scanner employed. Fifty-three subjects (aged 20-63 years, mean+/-SD 36+/-12 years) were studied at rest, and 31 of these subjects were also studied after dipyridamole in five institutions. Inter-institution consistency and intra-subject variation in MBF values were then evaluated. MBF averaged for all subjects was 0.93+/-0.34 ml min(-1) g(-1) at rest and 3.40+/-1.73 ml min(-1) g(-1) after the administration of dipyridamole, and the flow reserve (defined as the ratio of the two MBF values) was 3.82+/-2.12; these values are consistent with previous reports. Resting MBF values were significantly correlated with the heart rate-blood pressure product (RPP) (y=0.31+6.56E-5x, P<0.010), and RPP was in resting MBF observed in all institutions was well explained by the age-dependent RPP. No significant difference was observed in resting MBF among the institutions. Except in one institution, no significant difference was seen in dipyridamole MBF or myocardial flow reserve. No significant difference was found among the myocardial segments. Regional variation was reasonably small in five institutions, but was not acceptable in two institutions, which was attributed to the scanner performance. These observations suggest that the 15O-water PET technique is useful for a multicentre clinical study if the PET scanner can provide time-activity data with good count statistics.

Coronary Circulation↗
PubMed2000

Expression of hepatocyte growth factor (HGF)/scatter factor and its receptor c-MET correlates with poor prognosis in synovial sarcoma.

The hepatocyte growth factor (HGF)/c-MET signaling system plays an important role in the carcinogenesis of various organs. We investigated the expression of HGF and its receptor c-MET by immunohistochemistry (IHC) in 69 cases of synovial sarcoma and compared the findings with clinicopathologic parameters, proliferating activities evaluated by MIB-1 labeling index (MIB-1 LI), and patients' prognosis. Furthermore, mRNA analysis of HGF, c-MET, and SYT-SSX fusion gene was performed by reverse transcriptase-polymerase chain reaction (RT-PCR) in 22 concordant frozen materials. Twenty-one of 69 (30.4%) tumors showed positive reaction for c-MET, whereas 22 tumors (31.9%) were positive for HGF. In 10 cases, co-expression of HGF and c-MET was observed; however, there was no significant correlation between HGF and c-MET expression. HGF expression was correlated with female patients, large tumors (more than 5 cm), the presence of rhabdoid cells, low frequency of mast cells (<20/10 HPF), high nuclear grade (grade III), and high American Joint Committee (AJC) stage (III and IV). Conversely, c-MET expression was only correlated with large tumors. However, the coexpression of HGF and c-MET was significantly correlated with large tumor size, the existence of rhabdoid cells, and high AJC stage. Both the expression of HGF and the co-expression of HGF and c-MET showed a significantly high MIB-1 LI and were correlated with poor prognosis according to univariate analysis. Multivariate Cox analysis showed that high AJC stage, the expression of HGF, and a high MIB-1 LI (12.0>) independently had a negative impact on overall survival. In 22 frozen material cases evaluated by both IHC and RT-PCR, a statistically significant correlation was found between the 2 techniques. SYT-SSX fusion transcripts were detected in all 22 cases. Three tumors had SYT-SSX2 fusion transcripts, whereas 19 had SYT-SSX1 phenotype. Our results suggest that HGF/c-MET paracrine signaling may contribute to tumorigenesis and progression in synovial sarcoma.

Adult↗
PubMed2000

Haloperidol-induced rhabdomyolysis without neuroleptic malignant syndrome in a handicapped child.

A 6-year-old severely handicapped boy with haloperidol-induced mild rhabdomyolysis without neuroleptic malignant syndrome is reported. He had suffered from frontal lobe epilepsy, severe mental retardation and involuntary movements. To reduce the involuntary movements, oral administration of haloperidol was started. Haloperidol was effective for the involuntary movements, and he became well. However, his urine was sometimes dark brown, and the myoglobin level in his urine was increased. After discontinuation of haloperidol, his urine never became dark brown. It was suspected that haloperidol might cause mild rhabdomyolysis without neuroleptic malignant syndrome. Neuroleptic malignant syndrome is a rare but severe adverse effect of neuroleptics, and is usually accompanied by rhabdomyolysis. Although there have been a few adult cases presenting rhabdomyolysis without neuroleptic malignant syndrome, this patient might be the first child case with such symptoms. We have to pay attention to this syndrome when using haloperidol even in children.

Anti-Dyskinesia Agents↗
PubMed2000

Midazolam as a first-line agent for status epilepticus in children.

Midazolam is a water-soluble benzodiazepine, and has recently emerged as a safe and effective treatment option after ordinary antiepileptic therapy in the management of status epilepticus. However, midazolam as a first-line agent for status epilepticus in children has not been fully investigated. Intravenous midazolam was used for status epilepticus in 27 children (38 convulsive episodes) from January 1997 to December 1999 in our hospital. Among them, 10 patients (16 convulsive episodes) were treated with intravenous midazolam as a first-line agent. The causes of the seizures varied. Midazolam was administered as an intravenous bolus dose (0.1-0.3 mg/kg), followed by continuous intravenous infusion (1-8 microg/kg per min). In all epileptic episodes but one, the seizures stopped within 1 min without any adverse effects. These results were compatible with the previously reported ones. It is important to terminate status epilepticus which can cause brain damage. Midazolam seems to be effective and safe as a first-line therapy for status epilepticus in children.

Adolescent↗
PubMed2000

Engineering of an FGF-proteoglycan fusion protein with heparin-independent, mitogenic activity.

In the absence of heparan sulfate (HS) on the surface of target cells, or free heparin (HP) in the vicinity of their receptors, fibroblast growth factor (FGF) family members cannot exert their biological activity and are easily damaged by proteolysis. This limits the utility of FGFs in a variety of applications including treatment of surgical, burn, and periodontal tissue wounds, gastric ulcers, segmental bony defects, ligament and spinal cord injury. Here we describe an FGF analog engineered to overcome this limitation by fusing FGF-1 with HS proteoglycan (PG) core protein. The fusion protein (PG-FGF-1), which was expressed in Chinese hamster ovary cells and collected from the conditioned medium, possessed both HS and chondroitin sulfate sugar chains. After fractionation, intact PG-FGF-1 proteins with little affinity to immobilized HP and high-level HS modification, but not their heparitinase or heparinase digests, exerted mitogenic activity independent of exogenous HP toward HS-free Ba/F3 transfectants expressing FGF receptor. Although PG-FGF-1 was resistant to tryptic digestion, its physiological degradation with a combination of heparitinase and trypsin augmented its mitogenic activity toward human endothelial cells. The same treatment abolished the activity of simple FGF-1 protein. By constructing a biologically active proteoglycan-FGF-1 fusion protein, we have demonstrated an approach that may prove effective for engineering not only FGF family members, but other HP-binding molecules as well.

Amino Acid Sequence↗
PubMed2000

No change in spontaneous mutation frequency or specificity in dietary restricted mice.

It is well known that dietary restricted rodents live longer and are generally healthier than their ad libitum fed counterparts, with fewer tumors. Additionally, while dietary restriction appears to reduce the frequency of chemically induced mutation in laboratory animals, relatively little is known regarding the effect of dietary restriction on spontaneous mutational events. Although spontaneous mutation rates are generally low compared with chemically induced events, spontaneous mutations accumulate in most tissues over the lifetime of the animal and are therefore expected to contribute significantly to spontaneous neoplasia. It is generally presumed that dietary restriction results in less oxidative damage and a lowering of the mutation frequency. Here we report the results of dietary restriction on mutation frequency and specificity in lacI transgenic mice aged 6 and 12 months. Unexpectedly, no changes were observed in either the frequency or specificity of mutation in dietary restricted mice, compared with ad libitum controls. We therefore conclude that dietary restriction appears to have no appreciable effect on spontaneous mutation, at least in chromosomal DNA.

Age Factors↗
PubMed2000

Mutation frequency and specificity with age in liver, bladder and brain of lacI transgenic mice.

Mutation frequency and specificity were determined as a function of age in nuclear DNA from liver, bladder, and brain of Big Blue lacI transgenic mice aged 1.5-25 months. Mutations accumulated with age in liver and accumulated more rapidly in bladder. In the brain a small initial increase in mutation frequency was observed in young animals; however, no further increase was observed in adult mice. To investigate the origin of mutations, the mutational spectra for each tissue and age were determined. DNA sequence analysis of mutant lacI transgenes revealed no significant changes in mutational specificity in any tissue at any age. The spectra of mutations found in aging animals were identical to those in younger animals, suggesting that they originated from a common set of DNA lesions manifested during DNA replication. The data also indicated that there were no significant age-related mutational changes due to oxidative damage, or errors resulting from either changes in the fidelity of DNA polymerase or the efficiency of DNA repair. Hence, no evidence was found to support hypotheses that predict that oxidative damage or accumulation of errors in nuclear DNA contributes significantly to the aging process, at least in these three somatic tissues.

Aging↗
PubMed2000

Area under the plasma concentration-time curve of inorganic fluoride following sevoflurane anesthesia correlates with CYP2E1 mRNA level in mononuclear cells.

BACKGROUND: Because the amount of inorganic fluoride released after anesthesia with sevoflurane depends on the dose of administered sevoflurane and cytochrome P450 (CYP) 2E1 activity in the liver, a reliable and noninvasive probe for CYP2E1 would be useful for predicting plasma inorganic fluoride levels after anesthesia. In this study, the authors evaluated the relation between plasma concentration of inorganic fluoride after sevoflurane anesthesia and CYP2E1 mRNA level in mononuclear cells. METHODS: Twenty patients (American Society of Anesthesiologists physical status I), aged 20-68 yr undergoing body surface surgery with general anesthesia with sevoflurane were enrolled. One milliliter of blood was obtained before administration of sevoflurane and mononuclear cells were obtained. Levels of CYP2E1 mRNA in mononuclear cells were measured by competitive reverse transcription polymerase chain reaction with a specific primer and competitor for CYP2E1 mRNA. RESULTS: There was a significant correlation between level of CYP2E1 mRNA in mononuclear cells and the area under the plasma concentration-time curve of plasma inorganic fluoride from the beginning of sevoflurane administration to infinity in uninduced and uninhibited patients (r2 = 0.56; P < 0.01). CONCLUSIONS: Area under the plasma concentration-time curve of inorganic fluoride after sevoflurane anesthesia correlates with CYP2E1 mRNA in mononuclear cells in peripheral blood.

Adult↗
PubMed2000

(10E,12Z,15Z)-9-hydroxy-10,12,15-octadecatrienoic acid methyl ester as an anti-inflammatory compound from Ehretia dicksonii.

The methanol extract of Ehretia dicksonii provided (10E, 12Z, 15Z)-9-hydroxy-10,12,15-octadecatrienoic acid methyl ester (1) which was isolated as an anti-inflammatory compound. Compound 1 suppressed 12-Otetradecanoyl-phorbol-13-acetate (TPA)-induced inflammation on mouse ears at a dose of 500 microg (the inhibitory effect (IE) was 43%). Linolenic acid methyl ester did not inhibit this inflammation at the same dose. However, the related compounds of 1, (9Z,11E)-13hydroxy-9,11-octadecadienoic acid (5) and (9Z,llE)13-oxo-9,11-octadecadienoic acid (6), showed potent activity (IE500 microg of 63% and 79%, respectively). Compounds 1, 4 ((9Z, 12Z, 14E)-16-hydroxy-9,12,14-octadecatrienoic acid), 5 and 6 also showed inhibitory activity toward soybean lipoxygenase at a concentration of 10 microg/ml.

Animals↗