Biomedical subjects

Y Okamoto

Publications and source records attributed to Y Okamoto.

At least 145 records · Page 8Linked to original sources

PubMed2000

Identification of plasma antibody epitopes and gene abnormalities in Japanese hemophilia A patients with factor VIII inhibitor.

Eleven Japanese hemophilia A patients with anti-factor VIII (FVIII) inhibitors were studied to localize both their inhibitory antibody epitopes and their genotypes. The inhibitor epitopes were studied in nine severe hemophilia A patients by means of a scanning method using the oligopeptide panel covering the FVIII polypeptides without the B domain. The 107 15 mer-peptides were synthesized on solid-phase pins and analyzed for their reactivity with diluted patient plasma. As indicated previously, a series of peptides corresponding to the A2 and C2 domains were recognized by plasma antibodies from 2 patients and 4 patients, respectively. In contrast, all the antibodies bound to several epitopes in the A3 domain, while an epitope 1809-1821 covering the putative factor IX binding site was found in 3 patients. Southern blotting analysis showed that 8 out of 11 patients had either gene deletions or inversions of the FVIII gene, indicating a higher proportion of gross gene alterations in inhibitor-positive hemophilia A patients. However, the correlation of gene abnormality type with epitope location was not fully established.

Adult↗

PubMed2000

[Obstructive sleep apnea syndrome induced by ossification of the anterior longitudinal ligament with ankylosing spondylitis].

A 66-year-old man who had received a diagnosis of ankylosing spondylitis at the age of 50 was referred to our hospital for further evaluation of sleep apnea experienced for the last 3 years. Polysomnography yielded a diagnosis of obstructive sleep apnea syndrome with an apnea index of 41/hr. Computed tomographic scans demonstrated complete closure of the oropharynx during sleep at a site of marked ossification and hypertrophy of the cervical anterior longitudinal ligament. Nasal continuous positive airway pressure (nasal CPAP) with the use of chinstrap, but not nasal CPAP alone, dramatically decreased the patient's apnea index to 2.4/hr. We reported this case because, to the best of our knowledge, it is the first to demonstrate a causative association between ankylosing spondylitis and obstructive sleep apnea syndrome.

Aged↗

PubMed2000

[A comparative study on the clinical utility of cefozopran and cefpirome against complicated urinary tract infections].

Aiming at evaluating the utility of cefozopran (CZOP) against complicated urinary tract infections with the velocity of eradication of causal bacteria in early treatment and clinical efficacy by new criteria of UTIs, a comparative study was conducted using cefpirome (CPR) as the control drug. CZOP and CPR were administered by intravenous drip infusion at a dose of 1 g twice daily. The duration of treatment was for 5 days. The study method involved randomized assignment of the subjects to either group CZOP or group CPR. The results were as follows: 1. Of a total of 80 cases treated, 65 (CZOP group--32 cases, CPR group--33 cases) were evaluated for efficacy. 2. The overall clinical efficacy evaluation according to the criteria proposed by Japanese UTI Committee rated the CZOP group as 90.6% (29/32), and the CPR group as 90.9% (30/33), with no significant difference between the 2 groups. Clinical efficacy evaluated by attending physicians rated the CZOP group as 93.8% (30/32) and the CPR group as 90.9% (30/33). There was no significant difference between the 2 groups. 3. The efficacy rates to pyuria on day 2 were 26.7% and 0% for the CZOP group and the CPR group, respectively, indicating a higher efficacy rate for the former (p < 0.05). Those on after treatment were 59.4% and 54.5% for the CZOP group and the CPR group, respectively, with no significant difference between the 2 groups. 4. Regarding the bacteriological effect, the eradication rates of both groups were over 90% on day 1 and after treatment. There was no significant difference between the 2 groups. 5. Side effects occurred in 1 case (2.6%) out of 39 in the CZOP group and in 1 case (2.4%) out of 41 in the CPR group. Laboratory test value fluctuation was noted in 8 (20.5%) of 39 cases in the CZOP group and 11 (26.8%) of 41 cases in the CPR group. There was no significant difference between the 2 groups. The results indicate that CZOP achieves an early efficacy to pyuria, and is as useful as CPR against complicated urinary tract infections.

Adult↗

PubMed2000

[Prognostic factors of hepatocellular carcinoma: analysis by the proportional hazard model].

Five hundred fifty patients hospitalized to our hospital during 1990 to 1999 were studied. Subjects consisted of 413 males and 102 females and mean age was 62.1 years. Association with HBV infection, HCV infection and both infection was 11.1%, 78.4% and 2.5% respectively. According to the criteria based in Liver Cancer Study of Japan, 5 year survival rate in clinical stage I, II, III was 42.3%, 38.8% and 17.5%. Tumor morphology was nodular type in 78.9%, massive type in 9.1% and diffuse type in 10.5% of cases. Portal tumor thrombus and distal metastasis were observed in 19.9% and 6.3% of all cases. The 1-, 3- and 5-year survival rate in patients received any therapy was 80.8%, 44.6% and 28.7%, respectively. Analysis by the proportional hazard model showed that HBV infection, advanced clinical stage, multiple tumors, a tumor diameter in excess of 5 cm and AFP positivity were shown as significant factors on poor prognosis.

Carcinoma, Hepatocellular↗

PubMed2000

Factors affecting the volume of umbilical cord blood collections.

OBJECTIVE: Our purpose was to find factors that may help increase the number of the HSC (CD34+) collected from umbilical cord blood for transplantation. STUDY DESIGN: We assessed the effect of cesarean sections and vaginal deliveries on the volume of the umbilical cord blood collected from 155 healthy term neonates retrospectively. RESULTS: The volume of umbilical cord blood obtained in 29 cesarean deliveries was 103.9 +/- 33.6 ml compared with 84.2 +/- 25.3 ml collected in 126 vaginal deliveries. Although the percentage of CD34+ cells was comparable in both groups, the absolute number of CD34+ cells was significantly higher in the cesarean section group because of the larger volume collected. CONCLUSIONS: Cesarean sections may allow collection of significantly increased volumes of umbilical cord blood and numbers of CD34+ cells compared to vaginal deliveries.

Adult↗

PubMed2000

Clinical evaluation of inferior alveolar nerve block by injection into the pterygomandibular space anterior to the mandibular foramen.

The conventional inferior alveolar nerve block (conventional technique) has potential risks of neural and vascular injuries. We studied a method of inferior alveolar nerve block by injecting a local anesthetic solution into the pterygomandibular space anterior to the mandibular foramen (anterior technique) with the purpose of avoiding such complications. The insertion angle of the anterior technique and the estimation of anesthesia in the anterior technique were examined. The predicted insertion angle measured on computed tomographic images was 60.1 +/- 7.1 degrees from the median, with the syringe end lying on the contralateral mandibular first molar, and the insertion depth was approximately 10 mm. We applied the anterior technique to 100 patients for mandibular molar extraction and assessed the anesthetic effects. A success rate of 74% was obtained. This is similar to that reported for the conventional technique but without the accompanying risks for inferior alveolar neural and vascular complications.

Anesthesia, Dental↗

PubMed2000

Inferior alveolar nerve block by injection into the pterygomandibular space anterior to the mandibular foramen: radiographic study of local anesthetic spread in the pterygomandibular space.

We studied the spread of local anesthetic solution in the inferior alveolar nerve block by the injection of local anesthetic solution into the pterygomandibular space anterior to the mandibular foramen (anterior technique). Seventeen volunteers were injected with 1.8 mL of a mixture containing lidocaine and contrast medium utilizing the anterior technique. The course of spread was traced by fluoroscopy in the sagittal plane, and the distribution area was evaluated by lateral cephalograms and horizontal computed tomography. The results indicate that the contrast medium mixture spreads rapidly in the pterygomandibular space to the inferior alveolar nerve in the subjects who exhibited inferior alveolar nerve block effect. We concluded that the anesthetic effect due to the anterior technique was produced by the rapid distribution of anesthetic solution in the pterygomandibular space toward the mandibular foramen, and individual differences in the time of onset of analgesia may be due to differences in the histologic perineural tissues.

Adult↗

PubMed1999

Comparison between chemoradiation protocol intended for organ preservation and conventional surgery for clinical T1-T2 esophageal carcinoma.

PURPOSE: This retrospective study was designed to compare treatment results of the chemoradiation protocol with conventional surgery for thoracic T1-T2 esophageal squamous cell carcinoma. METHODS AND MATERIALS: Sixty-six patients with esophageal carcinoma, clinically diagnosed as T1 (tumor invading lamina propria or submucosa) or T2 (tumor invading muscularis propria) were treated for 12 consecutive years, from July 1986 to January 1998. The conventional surgery group included 30 patients who underwent esophagectomy with regional lymph node dissection. Twenty-one of them received postoperative radiotherapy. Thirty-six patients were assigned to the chemoradiation protocol, consisting of neoadjuvant chemoradiotherapy (44 Gy; CDDP: 60 mg/m2, day 1, bolus; 5-FU: 400 mg/m2, day 1-4, continuous), followed by either definitive radiotherapy with high-dose-rate intraluminal brachytherapy (total 70 Gy) for responders or surgery for nonresponders as in the conventional surgery group. Surgical candidates in both groups received intraoperative radiotherapy for abdominal lymphatics since 1991. RESULTS: In the protocol group, 4 patients underwent radical surgery after neoadjuvant chemoradiotherapy, and the remaining 32 underwent definitive chemoradiotherapy. Local control rates at 1 and 3 years were 85% and 70% in the T1/protocol group versus 91% and 80% in the T1/surgery group, and 83% and 83% in the T2/protocol group versus 94% and 80% in the T2/surgery group, respectively. There was no statistical significance. Overall 1- and 3-year survival rates were 100% and 83% in the T1/protocol group versus 82% and 72% in the T1/surgery group (p = 0.36), and 100% and 51% in the T2/protocol group, versus 95% and 68% in the T2/surgery group p = 0.61), respectively. There was no treatment-related mortality in either group. The rates of esophageal conservation were 92% in the T1/protocol group and 58% in the T2/protocol group. CONCLUSION: The chemoradiation protocol can result in comparable survival with conventional surgery for patients with T1-T2 esophageal carcinoma. A randomized trial between definitive chemoradiotherapy and surgery is required.

Aged↗

PubMed1999

Efficacy of the mobilization of peripheral blood stem cells by granulocyte colony-stimulating factor in pediatric donors.

The advantages/disadvantages of the use of peripheral blood stem cells (PBSCs) for allogeneic transplantation still need to be clarified, particularly in children. We compared the kinetics, efficacy, and safety of PBSC mobilization by granulocyte colony-stimulating factor (G-CSF) and collection by apheresis between healthy pediatric and adult donors. A total of 19 pediatric (median age, 6 years) and 25 adult healthy donors (median age, 37 years) were given 10 micro/kg/day of G-CSF for 5 consecutive days for PBSC mobilization, which were harvested by apheresis on days 5 and/or 6. All of the donors tolerated the whole procedures. Serum trough levels of G-CSF determined by ELISA were significantly lower in the 16 pediatric donors evaluated than in adults (n = 16) on days 3 and 4 (P < 0.05). Although the WBC counts on days 4 and 5 were significantly higher in adults than in children (P = 0.006 and 0.004, respectively), the numbers of circulating CD34+ cells/unit of blood were identical. The number of blood CD34+ cells collected per unit of blood processed was identical in both donor populations. We propose that PBSCs could be effectively mobilized and collected in small children so that they could be donors for adult patients.

Adolescent↗

PubMed1999

Expression of human scavenger receptor class B type I in cultured human monocyte-derived macrophages and atherosclerotic lesions.

The scavenger receptor class B type I (SR-BI) and its human homologue CLA-1 (CD36 and LIMPII Analogous-1) have recently been identified to bind HDL and mediate the selective uptake of HDL lipids. Tissue distribution of both murine and human receptors is quite similar, in that they are expressed abundantly in liver and steroidogenic tissues. However, expression and function of the human SR-BI (hSR-BI), in the periphery of reverse cholesterol transport such as macrophages, are still unclear. In the present study, we have raised two different kinds of anti-hSR-BI polypeptide antibodies (Abs): one against the extracellular domain and the other against the intracellular domain. We have investigated the expression of hSR-BI mRNA and immunoreactive mass in freshly isolated cultured human monocyte-derived macrophages (hMphi) and in atherosclerotic lesions. Contrary to the earlier report, hSR-BI mRNA was expressed in cultured hMphi and markedly upregulated with differentiation, determined by Northern blot and reverse transcriptase-based polymerase chain reaction analyses. The mRNA expression pattern during differentiation of hMphi was very similar to those of SR class A and another member of SR class B, CD36. Protein expression was confirmed by Western blot analyses with the above Abs to show a major 83-kDa band. Modified lipoproteins such as oxidized LDL and acetylated LDL induced a 5-fold increase in mRNA and protein expression of hSR-BI. Confocal immunofluorescence microscopy demonstrated that hSR-BI immunoreactive mass was detectable as a heterogeneous, punctate staining pattern. Furthermore, immunohistochemical analysis showed that immunoreactive mass of hSR-BI was detected in foam cells in human aortic atherosclerotic lesions and that there was no significant difference of staining patterns between the two Abs. This study clearly demonstrates that hSR-BI is expressed in the lipid-laden macrophages in human atherosclerotic lesions, suggesting that it is very important to know its function and regulation in hMphi to understand the biological utility of this molecule.

Animals↗

PubMed1999

Subcellular mechanisms of endothelin action in vascular system.

To elucidate the role of endothelin in the regulation of vascular function, the cellular and subcellular mechanisms for the synthesis of endothelin and the function of endothelin-receptors have been studied extensively. In this article, recent results regarding these problems are reviewed. (1) Oxidatively modified low-density-lipoprotein (LDL) reduces nitric oxide (NO) release via inhibition of the high-affinity arginine transporter of endothelial cells. (2) Endothelin-1-induced vasoconstriction is mediated by Ca2+ influx through a non-selective cation channel sensitive to 1-[beta-[3-(4-methoxyphenyl) propoxyl]-4-methoxyphenethyl]-1H-imidazole HCl (SK & F96365). (3) A distinct domain of the endothelin-receptor is required for the coupling of different G(alpha)-proteins. (4) Endothelin ET(A) receptor-mediated mitogenic activity is mediated by two pathways, one classical protein kinase C(PKC)-dependent, and the other phosphoinositide 3-kinase dependent. Both stimulate mitogen-activated protein kinase (MAPK). Endothelin ET(B) receptor-mediated mitogenic activity is also mediated by the PKC-dependent pathway. In contrast, endothelin ET(B) receptor-mediates differentiation and apoptosis via G(alpha)i coupling.

Animals↗

PubMed1999

The subcellular localization of SF2/ASF is regulated by direct interaction with SR protein kinases (SRPKs).

Serine/arginine-rich (SR) proteins play an important role in constitutive and alternative pre-mRNA splicing. The C-terminal arginine-serine domain of these proteins, such as SF2/ASF, mediates protein-protein interactions and is phosphorylated in vivo. Using glutathione S-transferase (GST)-SF2/ASF-affinity chromatography, the SF2/ASF kinase activity was co-purified from HeLa cells with a 95-kDa protein, which was recognized by an anti-SR protein kinase (SRPK) 1 monoclonal antibody. Recombinant SRPK1 and SRPK2 bound to and phosphorylated GST-SF2/ASF in vitro. Phosphopeptide mapping showed that identical sites were phosphorylated in the pull-down kinase reaction with HeLa extracts and by recombinant SRPKs. Epitope-tagged SF2/ASF transiently expressed in COS7 cells co-immunoprecipitated with SRPKs. Deletion analysis mapped the phosphorylation sites to a region containing an (Arg-Ser)8 repeat beginning at residue 204, and far-Western analysis showed that the region is required for binding of SRPKs to SF2/ASF. Further binding studies showed that SRPKs bound unphosphorylated SF2/ASF but did not bind phosphorylated SF2/ASF. Expression of an SRPK2 kinase-inactive mutant caused accumulation of SF2/ASF in the cytoplasm. These results suggest that the formation of complexes between SF2/ASF and SRPKs, which is influenced by the phosphorylation state of SF2/ASF, may have regulatory roles in the assembly and localization of this splicing factor.

Glutathione Transferase↗

PubMed1999

The folding funnel landscape for the peptide Met-enkephalin.

We study the free energy landscape of the small peptide Met-enkephalin. Our data were obtained from a generalized-ensemble Monte Carlo simulation taking the interactions among all atoms into account. We show that the free energy landscape resembles that of a funnel, indicating that this peptide is a good folder. Our work demonstrates that the energy landscape picture and folding concept, developed in the context of simplified protein models, can also be used to describe the folding in more realistic models.

Computer Simulation↗

PubMed1999

Chiral recognition of cellulose tris(5-fluoro-2-methylpheylcarbamate) toward (R)- and (S)-1, 1'-bi-2-naphthol detected by negative ion fast-atom bombardment mass spectrometry

Chiral recognition between cellulose tris(5-fluoro-2-methylphenylcarbamate) (MW > 120,000) as a host compound and (R,S)-1,1'-binaphthol (MW 286) as a guest compound was investigated by fast-atom bombardment mass spectrometry (FAB-MS). The use of negative ion FAB-MS made it possible to obtain a very simple mass spectrum of the guest compound with a high signal-to-noise ratio. Additionally, when nitrophenyl octyl ether, which has no OH group, was utilized as matrix, chiral recognition between the host and the guest compounds was unequivocally detected. Copyright 1999 John Wiley & Sons, Ltd.

Journal Article↗

PubMed1999

A Japanese herbal medicine, Chujo-to, has a beneficial effect on osteoporosis in rats.

The inhibitory effects of a Japanese herbal medicine, Chujo-to, on the progress of bone loss induced by ovariectomy in rats were investigated. Ovariectomized rats were administered with Chujo-to during weeks 7-14 after ovariectomy. At 14 weeks, the bone mineral density of the tibia from ovariectomized (OVX) rats had decreased by 27% compared with those in the sham-operated rats, and by a 18%-21% and 16% decrease after the administration of Chujo-to and 17 beta-oestradiol, respectively. The surface of a trabecular bone of the tibia in ovariectomized rats had a porous and fibrous appearance, while that of the same bone in sham-operated rats was composed of fine particles. After the administration of Chujo-to or 17 beta-oestradiol, the surface of trabecular bone maintained the porous and fibrous appearance. The uterine weight was not restored by Chujo-to but by 17 beta-oestradiol. These results suggest that Chujo-to has an efficacy on the osteoporosis of rats similar to 17 beta-oestradiol, but with a different mechanism.

Animals↗

PubMed1999

Chiral separations in capillary high-performance liquid chromatography and nonaqueous capillary electrochromatography using helically chiral poly(diphenyl-2-pyridylmethyl methacrylate) as chiral stationary phase.

Enantioseparations in nonaqueous capillary electrochromatography (CEC) are reported in this study for the first time, using wide-pore aminopropyl silica gel coated with helically chiral poly(diphenyl-2-pyridylmethyl methacrylate) (PDPM) as chiral stationary phase (CSP). The anodic electroosmotic flow (EOF) in a methanolic solution of ammonium acetate was used for the migration of neutral analytes through the packed bed in the capillaries. Four different techniques, high-performance liquid chromatography (HPLC) in common-size columns, capillary HPLC, pressure-assisted CEC and CEC were compared from the viewpoint of separation parameters. The latter three were performed with the same experimental setup, varying the relative contribution of the pressure-driven and the electrically driven flow to the overall mobility of the analyte. Capillary HPLC offers clear advantages compared to enantioseparations in common-size columns. However, for a given particle size of the packing material, CEC was not obviously advantageous compared to pressure-driven separations.

Chromatography, High Pressure Liquid↗

PubMed1999

Language supports for children's understanding of numerical fractions: cross-national comparisons.

This study examined Croatian, Korean, and U.S. children's knowledge of numerical fractions prior to school instruction. The research is part of an ongoing project examining the influence of language characteristics on mathematical thinking and performance. The part-whole quantitative relation denoted by numerical fractions may be easier to understand in East Asian languages like Korean. In these languages, the concept of fractional parts is embedded in the mathematics terms used for fractions. The results from this study suggest that the Korean vocabulary of fractions may influence the meaning 6- to 7-year-old children ascribe to numerical fractions and that this results in children being able to associate numerical fractions with corresponding pictorial representations prior to formal instruction.

Child↗

PubMed1999

Veterinary practice with chitin and chitosan.

Dramatic effects of chitin and chitosan on wound healing were demonstrated in field cases of many small animals (dogs and cats), food animals (338 cows) and 142 zoo animals. In comparison with conventional therapy with irrigation and antibiotic administration to wound, new treatment with chitin and chitosan permitted a substantial decrease in treatment frequency with minimum scar formation.

Animals↗