Biomedical subjects

K Ohta

Publications and source records attributed to K Ohta.

At least 127 records · Page 7Linked to original sources

PubMed2001

[Two cases of bronchus-associated lymphoid tissue lymphoma].

We report 2 cases of bronchus-associated lymphoid tissue lymphoma (BALT lymphoma), which is a rare disease. Patient 1 was a 76-year-old woman with a chief complaint of cough. Since plain chest radiography revealed an abnormal shadow in the hilum of the lung, she visited our hospital. Patient 2 was a 56-year-old man, who had been diagnosed as having pseudolymphoma at a medical check-up in a local hospital. During follow-up, however, he was referred to our hospital because of enlarged tumors and chest pain. In both patients, bronchofiberscopy demonstrated submucosal tumors and biopsy samples showed formation of lymphoepithelial lesions by centrocyte-like cells with a B-cell staining pattern. The patients were therefore diagnosed as having BALT lymphoma. Both received CEOP-E treatment, which improved the clinical symptoms but did not result in complete remission. The patients have been followed up after discontinuation of the medication. The progress of the disease has been slow, and both patients are alive as of September 2001.

Aged↗

PubMed2000

Selegiline and desmethylselegiline stimulate NGF, BDNF, and GDNF synthesis in cultured mouse astrocytes.

We investigated the effects of selegiline and desmethylselegiline on synthesis of neurotrophic factors in cultured mouse astrocytes. Treatment with 2 mM selegiline for 24 h increased the contents of NGF, BDNF, and GDNF in the culture medium 26-, 1.7-, and 4.2-fold over the control, respectively. With this drug the maximum relative mRNA levels of NGF, BDNF, and GDNF were 6.2-fold at 2 h, 3.4-fold at 6 h, and 2.7-fold at 2 h, respectively. Selegiline at 0.2 mM completely inhibited the MAO activity, but had no effect on the content of neurotrophic factors, suggesting that stimulation of neurotrophic factors by selegiline is independent of MAO-B inhibition. Desmethylselegiline at 1.68 mM for 24 h elevated the NGF, BDNF, and GDNF contents 4.1-, 1.7-, and 2.4-fold over the control, respectively; and the relative transcript levels of NGF, BDNF, and GDNF reached 2.6-fold at 2 h, 1.7-fold at 6 h, and 1.8-fold at 2 h, respectively. These findings suggest that selegiline and desmethylselegiline may protect neurons by up-regulating endogenous NGF, BDNF, and GDNF synthesis.

Amphetamines↗

PubMed2000

Diurnal fluctuation of sleep propensity and hormonal secretion across the menstrual cycle.

BACKGROUND: The fact that most women experience sleep changes across the menstrual cycle is thought to be associated with changes in circadian rhythms; however, few studies have investigated this relationship. METHODS: We applied an ultrashort sleep-wake schedule to eight healthy women and studied diurnal fluctuations in sleep propensity, sleepiness, rectal temperature, and serum concentrations of melatonin, thyroid-stimulating hormone, and cortisol in the follicular and luteal phases. RESULTS: In the luteal phase, amplitude of core body temperature, total melatonin secretions, and amplitudes of TSH and cortisol rhythms were significantly decreased, whereas sleepiness and occurrence of slow-wave sleep during the daytime were significantly increased. Differences in the amount of daytime slow-wave sleep across the menstrual cycle were positively correlated with differences in the daily mean rectal temperature. CONCLUSIONS: The findings suggest that the amplitude of circadian oscillation may be dampened in the luteal phase. Increased daytime sleepiness in the luteal phase may be associated with increased daytime slow-wave sleep, due possibly to changes in thermoregulation in the luteal phase.

Adult↗

PubMed2000

Novel triterpenoids inhibit both DNA polymerase and DNA topoisomerase.

As described previously, we found that new triterpenoid compounds, designated fomitellic acids A and B, which selectively inhibit the activities of mammalian DNA polymerases alpha and beta [Mizushina, Tanaka, Kitamura, Tamai, Ikeda, Takemura, Sugawara, Arai, Matsukage, Yoshida and Sakaguchi (1998) Biochem. J. 330, 1325-1332; Tanaka, Kitamura, Mizushina, Sugawara and Sakaguchi (1998) J. Nat. Prod. 61, 193-197] and that a known triterpenoid, ursolic acid, is an inhibitor of human DNA topoisomerases I and II (A. Iida, Y. Mizushina and K. Sakaguchi, unpublished work). Here we report that all of these triterpenoids are potent inhibitors of calf DNA polymerase alpha, rat DNA polymerase beta and human DNA topoisomerases I and II, and show moderate inhibitory effects on plant DNA polymerase II and human immunodeficiency virus reverse transcriptase. However, these compounds did not influence the activities of prokaryotic DNA polymerases such as Escherichia coli DNA polymerase I or other DNA metabolic enzymes such as human telomerase, T7 RNA polymerase and bovine deoxyribonuclease I. These triterpenoids were not only mammalian DNA polymerase inhibitors but also inhibitors of DNA topoisomerases I and II even though the enzymic characteristics of DNA polymerases and DNA topoisomerases, including their modes of action, amino acid sequences and three-dimensional structures, differed markedly. These triterpenoids did not bind to DNA, suggesting that they act directly on these enzymes. Because the three-dimensional structures of fomitellic acids were shown by computer simulation to be very similar to that of ursolic acid, the DNA-binding sites of both enzymes, which compete for the inhibitors, might be very similar. Fomitellic acid A and ursolic acid prevented the growth of NUGC cancer cells, with LD(50) values of 38 and 30 microM respectively.

Animals↗

PubMed2000

Inducible expression of a Th2-type CC chemokine thymus- and activation-regulated chemokine by human bronchial epithelial cells.

CCR4 is now known to be selectively expressed in Th2 cells. Since the bronchial epithelium is recognized as an important source of mediators fundamental to the manifestation of respiratory allergic inflammation, we studied the expression of two functional ligands for CCR4, i.e., macrophage-derived chemokine (MDC) and thymus- and activation-regulated chemokine (TARC), in bronchial epithelial cells. The bronchial epithelium of asthmatics and normal subjects expressed TARC protein, and the asthmatics showed more intense expression than the normal subjects. On the other hand, MDC expression was only weakly detected in the asthmatics, but the intensity was not significantly different from that of normal subjects. Combination of TNF-alpha and IL-4 induced expression of TARC protein and mRNA in bronchial epithelial A549 cells, which was slightly up-regulated by IFN-gamma. The enhancement by IFN-gamma was more pronounced in bronchial epithelial BEAS-2B cells, and a maximum production occurred with combination of TNF-alpha, IL-4, and IFN-gamma. On the other hand, MDC was essentially not expressed in any of the cultures. Furthermore, expressions of TARC protein and mRNA were almost completely inhibited by glucocorticoids. These results indicate that the airway epithelium represents an important source of TARC, which potentially plays a role via a paracrine mechanism in the development of allergic respiratory diseases. Furthermore, the beneficial effect of inhaled glucocorticoids on asthma may be at least in part due to their direct inhibitory effect on TARC generation by the bronchial epithelium.

Adult↗

PubMed2000

Simultaneous ion-exclusion/cation-exchange chromatography of anions and cations in acid rain waters on a weakly acidic cation-exchange resin by elution with sulfosalicylic acid.

A simple, selective, and sensitive method for the simultaneous determination of anions (sulfate, nitrate, and chloride) and cations (sodium, ammonium, potassium, magnesium, and calcium) in acid rain waters was developed using ion-exclusion/ cation-exchange chromatography with conductimetric detection. A weakly acidic cation-exchange resin column (Tosho TSKgel OA-PAK-A) and a sulfosalicylic acid-methanol-water eluent was used. With a mobile phase comprising 1.25 mM sulfosalicylic acid in methanol-water (7.5:92.5) at 1.2 ml/min, simultaneous separation and detection of the above anions and cations was achieved in about 30 min. Linear calibration plots of peak area versus concentration were obtained over the concentration ranges 0-1.0 mM for anions (R=0.9991) and 0-0.5 mM for cations (R=0.9994). Detection limits calculated at S/N=3 ranged from 4.2 to 14.8 ppb for the anions and from 2.4 to 12.1 ppb for the cations. The reproducibility of retention times was 0.14-0.15% relative standard deviation (RSD) for anions and 0.18-0.31% for cations, and reproducibility of chromatographic peak areas was 1.22-1.75% RSD for anions and 1.81-2.10% for cations. The method was applied successfully to the simultaneous determination of anions and cations in aerosols transported from mainland China to central Japan, as determined by a meteorological satellite data analyzer.

Anions↗

PubMed2000

Ion-chromatographic behavior of alkali metal cations and ammonium ion on zirconium-adsorbing silica gel.

The preparation and evaluation of zirconium-adsorbing silica gel (Zr-Silica) as an ion-exchange stationary phase in ion chromatography for inorganic anions and cations was carried out. The Zr-Silica was prepared by the reaction of silanol groups on the surface of the silica gel with zirconium butoxide (Zr(OCH2CH2CH2CH3)4) in ethanol. The ion-exchange characteristics of the Zr-Silica were evaluated using 10 mM tartaric acid at pH 2.5 as eluent. The Zr-Silica was found to act as a cation-exchanger under the eluent conditions. The retention behavior of alkali and alkaline earth metal cations was then investigated. The Zr-Silica column was proved to be suitable for the simultaneous separation of alkali metal cations and ammonium ion. Excellent separation of the cations on a 15 cm Zr-Silica column was achieved in 25 min using 10 mM tartaric acid as eluent.

Alkalies↗

PubMed2000

Indirect ultraviolet spectrophotometric detection in the ion chromatography of common mono- and divalent cations on an aluminium adsorbing silica gel column with tyramine-containing crown ethers as eluent.

The application of laboratory-made aluminium-adsorbing silica gel (Al-Silica) as a cation-exchange stationary phase to ion chromatography-indirect photometric detection (IC-IPD) for common mono- and divalent cations (Li+, Na+, NH+, K+, Mg2+ and Ca2+) was carried out by using protonated tyramine (4-aminoethylphenol) as eluent ion. When using 1.2 mM tyramine-0.2 mM oxalic acid at pH 4.5 as eluent, incomplete separation of the monovalent cations and complete separation of the divalent cations were achieved in 17 min. Then, the addition of crown ethers in the eluent was carried out for the complete separation of the mono- and divalent cations. As a result, when using 1.2 mM tyramine--0.2 mM oxalic acid at pH 4.5 containing either 5 mM 15-crown-5 (1,4,7,10,13-pentaoxacyclopentadecane) or 0.5 mM and 18-crown-6 (1,4,7,10,13,16-hexaoxacyclooctadecane) as eluent, excellently simultaneous separation of these cations was achieved in 21 min. The proposed IC-IPD was successfully applied to the determination of major cations in natural water samples.

Cation Exchange Resins↗

PubMed2000

Identification of a fmtA-like gene that has similarity to other PBPs and beta-lactamases in Staphylococcus aureus.

We identified a gene from Staphylococcus aureus, flp (fmtA-like protein), encoding a protein of 489 amino acid residues with a molecular mass of 56.4 kDa. The deduced amino acid sequence shows similarity to previously characterized penicillin binding proteins (PBPs) and FmtA of S. aureus (one of the factors which affect methicillin resistance). FLP protein has three motifs, which are conserved in PBPs and beta-lactamases, suggesting that it might be associated with cell wall synthesis. Recombinant FLP protein, however, lacks penicillin binding activity, and the inactivation of flp in two methicillin-resistant S. aureus strains did not cause a reduction in the methicillin resistance.

Amino Acid Motifs↗

PubMed2000

Novel anti-inflammatory compounds from Myrsine seguinii, terpeno-benzoic acids, are inhibitors of mammalian DNA polymerases.

Novel anti-inflammatory compounds, terpeno-benzoic acids, were found from the plant, Myrsine seguinii. The strongest of these anti-inflammatory agents, 3-geranyl-4-hydroxy-5-(3'-methyl-2'-butenyl) benzoic acid (compound 1), showed an inhibitory effect against enzymes involved in replication, such as calf DNA polymerase alpha (pol. alpha), rat DNA polymerase beta (pol. beta) and one of the beta family polymerases, calf thymus terminal deoxynucleotidyl transferase (TdT). The minimum inhibitory concentration (MIC) and IC50 values were 82 and 22 microM for pol. alpha, 86 and 11 microM for pol. beta, 140 and 46 microM for TdT, respectively. However, compound 1 did not influence the activities of plant DNA polymerases, human immunodeficiency virus type-1 reverse transcriptase, any of the prokaryotic DNA polymerases or DNA and RNA metabolic enzymes tested. Dose-dependent relationships were observed between the anti-inflammatory activities and the DNA polymerase-inhibitory activities of the four derivatives. The carboxylic acid moiety in the benzoic acid of the compounds appeared to be related to the inhibitory effects. The mode of action of the terpeno-benzoic acids against the polymerases and their relationships to the anti-inflammatory activity are discussed.

Animals↗

PubMed2000

Expression of CXCR4 in eosinophils: functional analyses and cytokine-mediated regulation.

We examined the expression of transcripts of a panel of chemokine receptors in human eosinophils and found intense constitutive expression of CXCR4 mRNA. Although surface CXCR4 protein was hardly detectable in the peripheral blood or freshly isolated eosinophils, surface expression of CXCR4 became gradually apparent during incubation at 37 degrees C. In contrast, the level of CCR3 expression was virtually unchanged during the incubation. Stromal cell-derived factor-1alpha (SDF-1alpha), the natural ligand of CXCR4, elicited an apparent Ca2+ influx in these cells and induced a strong migratory response comparable to that by eotaxin. The surface expression of CXCR4 in eosinophils was up-regulated by IFN-gamma, TNF-alpha, and TGF-beta while it was down-regulated by IL-4 and eosinophil-directed hemopoietins such as IL-5. The CXCR4 expression did not always parallel the apoptotic changes in cytokine-treated eosinophils. In contrast to IL-4 and IFN-gamma, IL-5 potently reduced the level of CXCR4 mRNA. It seems unlikely that CXCR4 is fundamentally involved in the pathogenesis of allergic disorders by inducing the migration of eosinophils toward inflammatory sites, because a Th2-dominant state down-regulates eosinophil CXCR4 expression. However, CXCR4 may affect the size of the mobilizable pool by holding eosinophils at noninflamed tissues. Th2-dominant state may favor the liberation of eosinophils by down-regulating CXCR4 expression. The interplay between CXCR4 and SDF-1alpha in eosinophils potentially plays an important role in the accumulation of these cells at the allergic inflammatory sites.

Cell Membrane↗

PubMed2000

Apomorphine up-regulates NGF and GDNF synthesis in cultured mouse astrocytes.

Apomorphine, a D1/D2 dopamine agonist, is an anti-parkinsonian drug. We examined the effects of apomorphine on synthesis of neurotrophic factors in cultured mouse astrocytes. After 24 h incubation with apomorphine, NGF and GDNF contents in the culture medium increased to 122-fold and 1.8-fold of the control, respectively; whereas the BDNF content did not change significantly. In Northern blot analysis, expression of NGF mRNA in astrocytes reached the maximum level at 6 h after addition of the drug. By semiquantitative RT-PCR analysis, the GDNF transcript level was found to reach 2.9-fold of the control level at 15 h. These results suggest that apomorphine may exert neuroprotective effects by stimulation of NGF and GDNF synthesis in astrocytes.

Animals↗

PubMed2000

Frequent occurrence of pre-existing alpha 2-->8-linked disialic and oligosialic acids with chain lengths up to 7 Sia residues in mammalian brain glycoproteins. Prevalence revealed by highly sensitive chemical methods and anti-di-, oligo-, and poly-Sia antibodies specific for defined chain lengths.

The pre-existence of alpha2-->8-linked disialic acid (di-Sia) and oligosialic acid (oligo-Sia) structures with up to 7 Sia residues was shown to occur on a large number of brain glycoproteins, including neural cell adhesion molecules (N-CAMs), by two highly sensitive chemical methods (Sato, C., Inoue, S., Matsuda, T., and Kitajima, K. (1998) Anal. Biochem. 261, 191-197; Sato, C., Inoue, S., Matsuda, T., and Kitajima, K. (1999) Anal. Biochem. 266, 102-109). This unexpected finding was also confirmed using a newly developed antibody prepared using a copolymer of alpha2-->8-linked N-acetylneuraminyl p-vinylbenzylamide and acrylamide as an immunogen and known antibodies whose immunospecificities were determined to be di- and oligo-Sia residues with defined chain lengths. The major significance of the new finding that di- and oligo-Sia chains exist on a large number of brain glycoproteins is 2-fold. First, it reveals a surprising diversity in the number and M(r) of proteins distinct from N-CAM that are covalently modified by these short sialyl glycotopes. Second, it suggests that synthesis of di- and/or oligo-Sia units may be catalyzed by alpha2-->8-sialyltransferase(s) that are distinct from the known polysialyltransferases, STX and PST, which are partially responsible for polysialylation of N-CAM.

Animals↗

PubMed2000

Studies on a novel DNA polymerase inhibitor group, synthetic sulfoquinovosylacylglycerols: inhibitory action on cell proliferation.

Some chemically synthesized sulfoquinovosylmonoacylglycerols (SQMG)-sulfoquinovosyldiacylglycerols (SQDG) have been reported to selectively and strongly inhibit the activities of mammalian DNA polymerases alpha and beta in vitro. In this study, using human cancer cell lines, we investigated the effects of SQMG-SQDG on the DNA polymerase in the cells. In the presence of n-decane, the IC(50) values on cell growth were approximately 1-5 microM for SQMG and about 0.3-1 microM for SQDG. The values were almost the same as the in vitro enzyme inhibitory levels. The cell lines were arrested in early S-phase by SQMG-SQDG at the concentrations of 0.1-4.7 microM in a manner dependent on incubation time, suggesting that SQMG-SQDG blocked the primary step of DNA replication by inhibiting DNA polymerase, possibly alpha-type. We also demonstrated the localization of SQMG in the cell using the fluorescent SQMG analog, SQMGalpha-NBDD, which was synthesized in our laboratory. SQMGalpha-NBDD was localized in the nucleus and on the nuclear surface, but the binding site seemed not to be the DNA/chromatin, suggesting that the SQMG-SQDG might interact with molecules located close to the DNA/chromatin and on the nuclear surface. These results suggested a correlation between the in vitro biochemical action of the SQMG-SQDGs and their intracellular mode of action.

Animals↗

PubMed2000

Distribution, chemical coding and origin of nitric oxide synthase-containing nerve fibres in the guinea pig nasal mucosa.

The distribution, chemical coding and origin of nitric oxide synthase (NOS)-containing nerve fibres in the respiratory mucosa of the nasal septum of the guinea pig were examined using nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) histochemistry and immunohistochemistry. A rich supply of NADPH-d-positive nerve fibres was observed around blood vessels and in nasal glands where nerve fibres frequently penetrated into the epithelia of acini and intralobular ducts. NADPH-d reactivity was also found in the nerve fibres located under or within the respiratory epithelium. Combined immunofluorescence and histochemical staining of the same preparation demonstrated virtually complete overlapping of NOS immunoreactivity and NADPH-d reactivity in nerve fibres, indicating that NADPH-d can be used as a marker for NOS-containing neurons. Double-labelling using antibodies to vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY), and calcitonin gene-related peptide (CGRP) revealed that NADPH-d-positive nerve fibres frequently contained VIP or NPY, but not CGRP. Pterygopalatine ganglionectomy significantly reduced the number of NADPH-d-positive nerve fibres innervating the respiratory epithelium as well as blood vessels and nasal glands. Neither superior cervical ganglionectomy nor sensory denervation by capsaicin treatment affected the distribution of NADPH-d-positive fibres. These results indicate that NOS-containing nerve fibres innervating the respiratory epithelium as well as blood vessels and nasal glands in the guinea pig originate mainly from the pterygopalatine ganglion, and suggest that NO may play a significant role as a neurotransmitter and/or neuromodulator in the control of the respiratory epithelium as well as vasculature and nasal glands.

Animals↗

PubMed2000

Identification of a gene coding for a new squamous cell carcinoma antigen recognized by the CTL.

Peptide-based specific immunotherapy has resulted in tumor regression in some melanoma patients. However, tumor Ags and peptides for specific immunotherapy, except for treatment of melanomas, have not yet been well identified. In this study, we report a gene encoding a new squamous cell carcinoma (SCC) Ag recognized by cells of the HLA-A24-restricted and tumor-specific CTL line. This gene with 3958-bp length was transcribed from the chromosome 6q22 with six exons, and its mRNA was ubiquitously expressed in both SCCs and normal tissues, and partly expressed in adenocarcinomas. The deduced 958-aa sequence encoded by this gene showed no similarity to any known amino acid sequences. This gene product had a characteristic of an endoplasmic reticulum-resident protein. A 100-kDa protein was detected in the vast majority of SCCs from various tissues, in majority of renal cell carcinomas and brain tumors, and in about one-third of melanomas and adenocarcinomas from various organs other than the breast. In contrast, it was not expressed at all in any of the normal cells or tissues tested, including the testis and fetal liver. Three different peptides at positions 93-101, 161-169, and 899-907 of this Ag were recognized by this CTL line, and all of them induced HLA-A24-restricted and tumor-specific CTLs from PBMCs of SCC patients. Therefore, these peptides may be useful for peptide-based specific immunotherapy of HLA-A24+ patients with SCC in various organs, as well as for treatment of other cancer.

Amino Acid Sequence↗

PubMed2000

Analysis of immunomodulatory activities of aqueous humor from eyes of mice with experimental autoimmune uveitis.

Aqueous humor (AqH) contains immunosuppressive factors, especially TGF-beta2, that contribute to the immune privileged status of the anterior chamber. However, this may not be true when the blood-ocular barrier is compromised by ocular inflammation. To determine the immunosuppressive status of AqH from murine eyes afflicted with experimental autoimmune uveitis, B10.A mice were immunized with interphotoreceptor retinoid-binding protein. AqH was collected from eyes of affected mice periodically after immunization and then evaluated for content of TGF-beta, proinflammatory cytokines, and the capacity to suppress anti-CD3-driven T cell proliferation. mRNA expression of selected cytokines in iris and ciliary body from inflamed eyes was analyzed by ribonuclease protection assay. We found that TGF-beta levels were significantly increased in AqH from EAU eyes on days 11, 17, and 28. AqH collected on day 11 (onset of disease) failed to suppress T cell proliferation and contained large amounts of locally produced IL-6 that antagonized TGF-beta. In contrast, AqH collected at 17 days (when ocular inflammation was progressively severe) re-expressed the ability to suppress T cell proliferation, in this case due to high levels of blood-derived TGF-beta1 and eye-derived TGF-beta2 in the absence of IL-6. Thus, during the onset of experimental autoimmune uveitis, the ocular microenvironment loses its immunosuppressive properties due to local production of IL-6. But as inflammation mounts, AqH IL-6 content falls, and the fluid reacquires sufficient TGF-beta eventually to suppress immunogenic inflammation. The paradoxical roles of IL-6 in antagonizing TGF-beta, while promoting TGF-beta accumulation during ocular inflammation, is discussed.

Adjuvants, Immunologic↗

PubMed2000

p97 ATPase, an ATPase involved in membrane fusion, interacts with DNA unwinding factor (DUF) that functions in DNA replication.

DNA unwinding factor (DUF) unwinds duplex DNA and is supposed to function in DNA replication in Xenopus egg extracts. Here we report the isolation and analysis of a DUF-interacting factor. By immunoprecipitation, we found that p97 ATPase (p97) interacts with DUF in Xenopus egg extracts. This interaction was confirmed by the in vitro binding of purified p97 with DUF. When sperm chromatin was added to Xenopus egg extracts to construct nuclei active in DNA replication, p97 was incorporated into the nuclei. These data suggest that the complex of DUF and p97 may function in DNA replication.

Adenosine Triphosphatases↗