Biomedical subjects

S Kodama

Publications and source records attributed to S Kodama.

At least 19 recordsLinked to original sources

PubMed2001

Preferential expression of an intact WRN gene in Werner syndrome cell lines in which a normal chromosome 8 has been introduced.

Werner syndrome (WS) is a premature aging syndrome caused by mutations in the WRN gene. All mutations of the WRN gene reported thus far are predicted to produce the truncated WRN proteins. The mRNAs that contain chain-termination mutations are supposed to be unstable due to degradation by nonsense-mediated mRNA decay (NMD). In the present study, we investigated the expressions of intact and nonsense-mutated WRN genes in Werner syndrome cell lines in which a normal chromosome 8 had been introduced by microcell fusion. We demonstrate here that the expression of the mutated WRN gene that produces nonsense mRNAs remains at low levels, resulting in the preferential expression of the intact WRN gene in the WS microcell hybrids. This result supports the idea that imperfect messages containing premature termination codons are eliminated by the RNA surveillance system, suggesting the significance of the NMD mechanism in the etiology of Werner syndrome.

Cell Line↗

PubMed2001

Direct chiral resolution of tartaric acid in food products by ligand exchange capillary electrophoresis using copper(II)-D-quinic acid as a chiral selector.

Chiral resolution of native DL-tartaric acid was performed by ligand-exchange capillary electrophoresis using copper(II)-D-quinic acid as a chiral selector. Factors affecting chiral resolution, migration time, and peak area of tartaric acid were studied. The running conditions for optimum separation of tartaric acid were found to be 1 mM copper(II) sulfate-10 mM D-quinic acid (pH 5.0) with an effective voltage of -15 kV at 30 degrees C, using direct detection at 250 nm, and resolution of racemic tartaric acid was approximately 1.3. With this system, chiral resolution of DL-tartaric acid in food products was conducted successfully.

Copper↗

PubMed2001

Enantiomeric purity determination of malic acid in apple juices by multi-beam circular dichroism detection.

A multi-beam circular dichroism (CD) detector which is easily constructed by inserting inexpensive optics into a conventional photo-diode array detector has an advantage of simultaneous detection of the absorbance and CD. The enantiomeric purity determination of malic acid in beverages was performed by this detection system. Malic acid when complexed with Cu(II) was found to have an absorbance maximum at around 750 nm. The L-malic acid-Cu(II) complex showed a positive Cotton effect in its absorbance band and its anisotropy factor (delta epsilon/epsilon) was relatively large at about 1/170. This complex was retained on a reversed-phase column with the addition of racemic 2-hydroxy-3-methylbutyric acid to the mobile phase as the ligand. A plot of the relative peak areas between the CD and the absorption (delta abs/abs) versus optical purity showed good linearity with a correlation coefficient of 0.999, and the precision expressed as the relative standard deviation of the errors from the regression line was +/-2.7% (2sigma). The accuracy of the proposed method was assessed by capillary electrophoresis. Eight commercially available juice products were analyzed using this method. Five of them were thought to be adulterated with synthetic malic acid.

Beverages↗

PubMed2001

Extremely low-dose ionizing radiation causes activation of mitogen-activated protein kinase pathway and enhances proliferation of normal human diploid cells.

We demonstrated here that X-ray irradiation at very low doses of between 2 and 5 cGy stimulated proliferation of normal human diploid cells and human tumor cells. Higher doses of irradiation at >1 Gy accumulated p53 protein and induced phosphorylation of extracellular signal-regulated kinase (ERK) 1/2. Phosphorylation of ERK1/2 decreased with dose down to 50 cGy, however, doses of between 5 cGy and 2 cGy phosphorylated ERK1/2 as efficiently as higher doses of X-rays, whereas the p53 protein level was not changed by doses <50 cGy. We found that mitogen-activated protein /ERK kinase (MEK) 1 was phosphorylated with both 2 cGy and 6 Gy of X-rays, and that activated ERK1/2 augmented phosphorylation of Elk-1 protein. The specific epidermal growth factor receptor tyrosine kinase inhibitor, AG1478, decreased phosphorylation of the ERK1/2 proteins induced by 2 cGy or 6 Gy of X-rays, and similar suppressive effect was observed with MEK inhibitor, PD98059. Suppression of ERK1/2 phosphorylation with these inhibitors alleviated enhanced proliferation of normal human cells by low-dose irradiation. Furthermore, overexpression of ERK2 in NCI-H1299 human lung carcinoma cells potentiated enhanced proliferation, whereas down-regulation of ERK2 using the antisense ERK2 gene abrogated the stimulative effect of low-dose irradiation. These results indicate that a limited range of low-dose ionizing radiation differentially activates ERK1/2 kinases via activation of epidermal growth factor receptor and MEK, which causes enhanced proliferation of cells receiving very low doses of ionizing radiation.

Cell Division↗

PubMed2001

Conservative therapy for adenocarcinoma and atypical endometrial hyperplasia of the endometrium in young women: central pathologic review and treatment outcome.

Thirty-nine patients with endometrioid adenocarcinoma (EA) and atypical hyperplasia (AH) of the endometrium who received conservative treatment to preserve fertility were collected from member institutions of the Japan Gynecologic Oncology Study Group. Twenty-nine and ten were originally diagnosed with EA without myometrial invasion and AH, respectively. We performed a central pathological review to make definite diagnoses, and the diagnosis of EA in 29 cases was changed to AH in ten, complex hyperplasia in three and atypical polypoid adenomyoma in three, and AH in ten was changed to EA in one and simple hyperplasia in one. Nine of 12 women (75%) with EA and 15 of 18 women (83%) with AH had an initial response to medroxyprogesterone acetate (MPA) treatment. Two of nine responders with EA later developed relapse, and one of them had metastasis to the left obturator lymph node. Two became pregnant, and one delivered one full-term infant. One of the responders with AH had a relapse in the endometrium. Five became pregnant, and four delivered four normal infants. The young women with endometrial carcinoma localized in the endometrium who wish to preserve fertility may be treated as successfully with MPA as those with AH.

Adenocarcinoma↗

PubMed2001

Multi-beam polarized photometric detector for high-performance liquid chromatography.

A novel multi-beam polarized photometric detector (PPD) for high-performance liquid chromatography (HPLC) is described. By pairing a polarizing prism with a thin quartz plate as a retarder, many linear polarized beams are produced at every 1/2 wavelength of the plate, and the polarizing axes of the adjacent beams intersect each other. The addition of another prism inclining its polarizing axis by pi/4 against the first one enables the simultaneous measurement of optical rotations based on the PPD at many wavelengths. The combination of these optics with a photo-diode array detector can be used to construct a modulated type polarimeter. This detector is designed to measure the optical rotation of an analyte at its absorption band. The spline function connecting the points at 1/4 wavelengths of the plate was used as a baseline to extract the PPD waves. The use of the similarity factor as a noise filter gave high sensitivity. Application of the proposed technique to an analyte carrying the Cotton absorption band provided good results.

Chromatography, High Pressure Liquid↗

PubMed2001

Direct chiral resolution of malic acid in apple juice by ligand-exchange capillary electrophoresis using copper(II)-L-tartaric acid as a chiral selector.

Chiral resolution of native DL-malic acid was achieved by ligand-exchange capillary electrophoresis using copper(II)-L-tartrate as a chiral selector. Factors affecting chiral resolution, migration time, and peak area of malic acid were studied. The running conditions for optimum separation of malic acid were found to be 1 mM copper(II) sulfate-1 mM L-tartrate (pH 5.1) with an effective voltage of -20 kV at 30 degrees C, using direct detection at 280 nm, and resolution (Rs) of racemic malic acid was approximately 4. With this system, D- and L-malic acids in apple juice were analyzed successfully.

Beverages↗

PubMed2001

Prognostic factors of stage IV epithelial ovarian cancer: a multicenter retrospective study.

OBJECTIVE: In the present study, we conducted a multicenter retrospective analysis to elucidate the prognostic factors of stage IV epithelial ovarian cancer. METHODS: In November 1999, 24 Japanese institutions received questionnaires regarding stage IV epithelial ovarian cancer patients. Eligibility criteria included all patients with stage IV epithelial ovarian cancer who were surgically confirmed and initially treated in each institution between January 1990 and December 1997. Data were collected regarding age, performance status, tumor histologic subtype, site of metastasis, preoperative CA125, cytoreductive surgery, residual disease after cytoreductive surgery, and response to primary chemotherapy. Survival analysis and comparisons were performed by univariate and multivariate methods. RESULTS: Two hundred twenty-five patients with stage IV ovarian cancer were identified. The median age of the patients was 54 years. The most common site of extraperitoneal disease was malignant pleural effusion (39.6%). Of the 225 patients who underwent an attempt at surgical debulking, 70 (31.1%) were optimally cytoreduced. Most patients received platinum-based combination chemotherapy for primary chemotherapy. In multivariate analysis, performance status, histology, and residual disease after cytoreductive surgery were independent prognostic predictors of outcome. The overall median survival for optimally debulked patients was 32 months compared to 16 months for suboptimally debulked patients (P < 0.0001, hazard ratio: 0.415). CONCLUSION: Optimal surgical debulking, performance status, and histology appear to be important prognostic factors of survival in patients with stage IV epithelial ovarian cancer.

Adult↗

PubMed2001

Aberrant brain activation following motor skill learning in schizophrenic patients as shown by functional magnetic resonance imaging.

BACKGROUND: Motor skill learning may be impaired in schizophrenia. While functional brain imaging studies have shown reduced activation during motor task performance in schizophrenic patients, brain activity changes with motor skill learning in these patients have not been studied by functional imaging. METHODS: A sequential complex motor task involving the right hand was performed by nine medicated schizophrenic patients and 10 age-matched healthy controls. Functional magnetic resonance images were obtained using a gradient echo, echoplanar imaging (EPI) pulse sequence before and after 1 week of training in performing the task. RESULTS: Bilaterally, patients showed significantly less blood oxygenation level-dependent (BOLD) signal response in the premotor area (PMA) before beginning motor training than controls. BOLD signal response increased in the left PMA of schizophrenic patients after 1 week of motor training; in contrast, the signal decreased in the left PMA of control subjects. Training effects concerning the number of finger movement sequences achieved did not differ between groups. Daily neuroleptic dose did not significantly affect changes with training in BOLD signal response in the PMA. CONCLUSIONS: These preliminary results suggest that schizophrenic patients have dysfunction of neural networks in areas including the PMA that are involved in executing a complex motor task. In terms of brain activity, motor learning may be less efficient or slower in the patients than in healthy subjects.

Adolescent↗

PubMed2001

Characteristics of a column suitable for capacity gradient chromatography with a borate eluent.

In capacity gradient elution, the gradient separation of ionic species is achieved by decreasing the ion-exchange capacity of a column during the course of the separation. Diol-type hydroxy groups on the resin surface form anionic complexes with borate as an eluting reagent. Thus, a chemically bonded anion-exchange column enriched with residual hydroxy groups allows the creation of a capacity gradient. An increase in the amount of the complex formed gradually brings about a decrease in the ion-exchange capacity of the column, and strongly bound analyte ions are eluted. We investigated the characteristics of a column suitable for this eluent system. The concentration of borate eluent required to remove the ion-exchange capacity depended inversely on the ratio of the residual hydroxy groups to functional groups. On a column in which this ratio was approximately 100, the ion-exchange capacity could easily be adjusted by using a low concentration of mannitol as a competing reagent. Use of this column led to very small baseline shifts during the borate-mannitol gradients, and to the simultaneous determination of anions with widely varying retention times.

Borates↗

PubMed2001

Increase in tonsillar germinal centre B-1 cell numbers in IgA nephropathy (IgAN) patients and reduced susceptibility to Fas-mediated apoptosis.

IgAN is a common form of primary glomerulonephritis and also a disease of tonsillar focal infection. The comprehensive mechanism underlying this disease remains to be defined. To better understand its pathogenesis, we investigated tonsillar CD5+ B cells (B-1 cells) with respect to IgA synthesis. Germinal centre (GC) B cells were isolated from the tonsils of IgAN patients and the number of B-1 cells in the GC determined by flow cytometry. GC B-1 and B-2 (CD5- B) cells were purified by cell sorter, the cells were incubated with agonist anti-CD40 MoAb and the ability for antibody production by B-1 and B-2 cells determined by ELISPOT assay. GC B-1 cells and B-2 cells were incubated with agonist anti-Fas MoAb, and apoptosis in GC B-1 cells and B-2 cells was analysed by flow cytometry. Although B-1 cells do not usually take part in the GC reaction, an increase in B-1 cell numbers was observed in the GC of tonsils from IgAN patients. These B-1 cells were likely IgA1 antibody-producing cells, since the prominent IgA subclass in IgAN is generally considered to be IgA1. Although Fas-dependent apoptosis is essential for the elimination of activated B cells, these B-1 cells showed a reduced susceptibility to Fas-mediated apoptosis. It is conceivable that activated B-1 cells may survive in the GC due to impaired apoptosis and thus produce abnormal antibodies. These findings suggest that the immune responses of B-1 cells in the tonsillar GC could thus have an impact on the pathogenesis of IgAN.

Adolescent↗

PubMed2001

ONO1714, a new inducible nitric oxide synthase inhibitor, attenuates sepsis-induced diaphragmatic dysfunction in hamsters.

UNLABELLED: Sepsis causes impairment of diaphragmatic contractility and endurance capacity. Nitric oxide (NO) produced via inducible NO synthase (iNOS) has been implicated in the pathogenesis. Peroxynitrite, a NO-derived powerful oxidant, may be responsible for infection-induced diaphragmatic muscle failure. Therefore, we examined whether ONO1714, a new selective iNOS inhibitor, prevents sepsis-induced diaphragmatic dysfunction. Fifty male Golden-Syrian hamsters were randomly divided into five groups: hamsters that underwent sham laparotomy alone and received saline injection (Group Sham), those that underwent cecal ligation with puncture (CLP) and received saline injection (Group Sepsis), those that underwent sham laparotomy and received injection of ONO1714 0.3 mg/kg (Group Sham-ONO1714high), those that underwent CLP and received ONO1714 0.1 mg/kg (Group Sepsis-ONO1714low), and those that underwent CLP and received ONO1714 0.3 mg/kg (Group Sepsis-ONO1714high). ONO1714 or saline was intraperitoneally injected 10 min before surgery. Diaphragmatic contractility was assessed in vitro using diaphragm muscle strips excised 24 h after operation. Diaphragm fatigability was assessed by time until tension decreased to 50% of the initial value (T50%) during fatigue trials. Twitch, tetanic tensions, and T50% during fatigue trials were reduced in Group Sepsis. Pretreatment with ONO1714 dose-dependently attenuated sepsis-induced diaphragmatic contractile profiles and endurance capacity. CLP increased plasma nitrite/nitrate (NOx; stable NO metabolites), and diaphragm malondialdehyde (MDA; a product of lipid peroxidation), positive immunostaining for nitrotyrosine (peroxynitrite footprint), and iNOS activity. ONO1714 attenuated the increase. This beneficial effect of ONO1714 may be attributable, in part, to inhibition of peroxynitrite-induced lipid peroxidation in the diaphragm. IMPLICATIONS: Sepsis impairs diaphragmatic contractility and endurance capacity, which may be involved in acute respiratory failure. Pretreatment with ONO1714, a new selective inducible nitric oxide synthase inhibitor, attenuated sepsis-induced diaphragmatic dysfunction in hamsters.

Amidines↗

PubMed2001

Propofol attenuates diaphragmatic dysfunction induced by septic peritonitis in hamsters.

BACKGROUND: Sepsis or peritonitis impairs diaphragmatic contractility and endurance capacity. Peroxynitrite, a powerful oxidant formed by superoxide and nitric oxide, has been implicated in the pathogenesis. Propofol scavenges this reactive molecule. The authors conducted the current study to evaluate whether propofol prevents diaphragmatic dysfunction induced by septic peritonitis. METHODS: Forty male Golden-Syrian hamsters (120-140 g) were randomly classified into five groups. Groups sham and sham-propofol 50 underwent sham laparotomy alone, whereas groups sepsis, sepsis-propofol 25, and sepsis-propofol 50 underwent cecal ligation with puncture. Groups sham and sepsis received infusion of intralipid, whereas groups sham-propofol 50, sepsis-propofol 25, and sepsis-propofol 50 received propofol at rates of 50, 25, and 50 mg.kg(-1).h(-1), respectively. Intralipid or propofol was subcutaneously infused from 3 h before surgery until 24 h after operation, when all hamsters were killed. Diaphragmatic contractility and fatigability were assessed in vitro using diaphragm muscle strips. Peroxynitrite formation in the diaphragm was assessed by nitrotyrosine immunostaining. Plasma nitrite-nitrate concentrations and diaphragmatic concentrations of malondialdehyde were determined. Using another set of animals, diaphragmatic inducible nitric oxide synthase activity was also measured. RESULTS: Twitch, tetanic tensions, and tensions during fatigue trials were reduced in group sepsis compared with group sham. In group SEPSIS, diaphragm malondialdehyde and inducible nitric oxide synthase activity, and plasma nitrite-nitrate concentrations increased, and positive immunostaining for nitrotyrosine residues was found. Propofol attenuated these changes. CONCLUSIONS: Pretreatment with propofol attenuated diaphragmatic dysfunction induced by septic peritonitis in hamsters assessed by contractile profiles and endurance capacity. This beneficial effect of propofol may be caused, in part, by inhibition of lipid peroxidation in the diaphragm caused by the powerful oxidant.

Animals↗

PubMed2001

Mucosal immunity of the middle ear: analysis at the single cell level.

OBJECTIVE: Studies have suggested that the middle ear is a potential site of immunological regulation and that the middle ear mucosa constitutes a part of the mucosal immune system. We clarify the characteristics of the middle ear mucosa with respect to immune potential. STUDY DESIGN: We investigated lymphocyte subsets, mRNA of cytokines, and induction of antigen-specific IgA-producing cells in the middle ear mucosa in specific pathogen-free C57BL/6 mice. RESULTS: Flow cytometric analysis showed a certain amount (10%-15%) of gammadelta T cells among CD3+ T cells. P6-specific IgA-producing cells were induced by intranasal immunization with P6 together with cholera toxin. RT-PCR assay of mucosal T cells detected mRNA of Th2 type cytokines such as IL-5 and IL-10. CONCLUSION: These findings support the fact that the middle ear is potentially an effector site of the mucosal immunity.

Animals↗

PubMed2001

Intranasal immunization enhances clearance of nontypeable Haemophilus influenzae and reduces stimulation of tumor necrosis factor alpha production in the murine model of otitis media.

Nontypeable Haemophilus influenzae (NTHi) is a major pathogen causing otitis media (OM). One of the outer membrane proteins of NTHi, P6, is a common antigen to all strains and is considered a candidate for mucosal vaccine. We have previously reported that intranasal immunization with P6 and cholera toxin (CT) could induce P6-specific immunoglobulin A (IgA) antibodies in the middle ear. In the present study, we assessed the effect of intranasal immunization for the protection against NTHi-induced OM. Mice were immunized intranasally with P6 and CT as an adjuvant on days 0, 7, and 14. Control mice were given phosphate-buffered saline (PBS) without antigen. One week after the final immunization, a suspension of live NTHi (10(7) CFU) was injected into the tympanic cavity to induce experimental OM. On days 3 and 7 after bacterial challenge, mice were killed and middle ear effusions (MEEs) were collected. All immunized mice showed elevated titers of P6-specific antibodies in MEEs. The rank order of specific antibody included, from highest to lowest levels, IgG, IgA, and IgM. In addition, immunized mice showed enhanced clearance of NTHi from the middle ear and the number of NTHi in MEEs of immunized mice was reduced by 97% on day 3 and by 92% on day 7 after bacterial challenge relative the number in the MEEs of control mice. The protective effect of intranasal immunization on the incidence of NTHi-induced experimental OM was evident on day 7 after challenge. By day 7, the number of MEEs in immunized mice was 64% less than that in control mice and the incidence of NTHi culture-positive MEEs in immunized mice was 56% less than that in control mice. Less stimulation of tumor necrosis factor alpha (TNF-alpha) production in the middle ear was evident on day 3 after challenge. Immunized mice showed lower concentrations of TNF-alpha in MEEs. These results indicate that intranasal immunization affords protection against experimental OM as evidenced by enhanced clearance of NTHi and less stimulation of TNF-alpha production in the middle ear. These findings suggest that a nasal vaccine might be useful for preventing OM.

Administration, Intranasal↗

PubMed2001

Mitochondrial coupling factor 6 as a potent endogenous vasoconstrictor.

We demonstrated recently that coupling factor 6, an essential component of the energy-transducing stalk of mitochondrial ATP synthase, suppresses the synthesis of prostacyclin in vascular endothelial cells. Here, we tested the hypothesis that coupling factor 6 is present on the cell surface and is involved in the regulation of systemic circulation. This peptide is present on the surface of CRL-2222 vascular endothelial cells and is released by these cells into the medium. In vivo, the peptide circulates in the vascular system of the rat, and its gene expression and plasma concentration are higher in spontaneously hypertensive rats (SHRs) than in normotensive controls. Elevation of blood pressure with norepinephrine did not affect the plasma concentration of coupling factor 6. Intravenous injection of recombinant peptide increased blood pressure, apparently by suppressing prostacyclin synthesis, whereas a specific Ab to coupling factor 6 decreased systemic blood pressure concomitantly with an increase in plasma prostacyclin. Interestingly, the antibody's hypotensive effect could be abolished by treating with the cyclooxygenase inhibitor indomethacin. These findings indicate that mitochondrial coupling factor 6 functions as a potent endogenous vasoconstrictor in the fashion of a circulating hormone and may suggest a new mechanism for hypertension.

Amino Acid Sequence↗

PubMed2001

Reversal of established autoimmune diabetes by restoration of endogenous beta cell function.

In NOD (nonobese diabetic) mice, a model of autoimmune diabetes, various immunomodulatory interventions prevent progression to diabetes. However, after hyperglycemia is established, such interventions rarely alter the course of disease or allow sustained engraftment of islet transplants. A proteasome defect in lymphoid cells of NOD mice impairs the presentation of self antigens and increases the susceptibility of these cells to TNF-alpha-induced apoptosis. Here, we examine the hypothesis that induction of TNF-alpha expression combined with reeducation of newly emerging T cells with self antigens can interrupt autoimmunity. Hyperglycemic NOD mice were treated with CFA to induce TNF-alpha expression and were exposed to functional complexes of MHC class I molecules and antigenic peptides either by repeated injection of MHC class I matched splenocytes or by transplantation of islets from nonautoimmune donors. Hyperglycemia was controlled in animals injected with splenocytes by administration of insulin or, more effectively, by implantation of encapsulated islets. These interventions reversed the established beta cell-directed autoimmunity and restored endogenous pancreatic islet function to such an extent that normoglycemia was maintained in up to 75% of animals after discontinuation of treatment and removal of islet transplants. A therapy aimed at the selective elimination of autoreactive cells and the reeducation of T cells, when combined with control of glycemia, is thus able to effect an apparent cure of established type 1 diabetes in the NOD mouse.

Adoptive Transfer↗

PubMed2001

Chromosome aberration analysis in persons exposed to low-level radiation from the JCO criticality accident in Tokai-mura.

Chromosome aberrations were studied in peripheral blood lymphocytes of 43 persons who were exposed to low-level radiation of mixed neutrons and gamma-rays resulting from the JCO criticality accident. When the age-adjusted frequencies of dicentric and ring chromosomes were compared with the dose calibration curve established in vitro for 60Co gamma-rays as a reference radiation, a significant correlation was observed between the chromosomally estimated doses and the documented doses evaluated by physical means. The regression coefficient of the chromosomal doses against the documented doses, 1.47 +/- 0.33, indicates that the relative biological effectiveness of fission neutrons at low doses is considerably higher than that currently adopted in the radiation protection standard.

Adult↗