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Biomedical subjects

M Kataoka

Publications and source records attributed to M Kataoka.

At least 199 records · Page 11Linked to original sources
PubMed1997

Characterization of a methyl-accepting chemotaxis protein gene, dmcA, from the oral spirochete Treponema denticola.

A gene, dmcA, expressing a methyl-accepting chemotaxis protein (MCP) from the oral spirochete Treponema denticola has been characterized. The gene was initially identified as an open reading frame immediately upstream from the previously characterized prtB protease gene of strain ATCC 35405. Nucleotide sequencing of the dmcA gene revealed a potential 57-kDa protein product with extensive homology with the signaling regions of MCPs from a variety of bacteria. The protein expressed in Escherichia coli cross-reacted with anti-Trg (E. coli MCP) serum, confirming its homology with MCPs. Northern blot and primer extension analyses identified the transcription start site of the monocistronic dmcA mRNA. By utilizing a T. denticola gene inactivation system recently developed in this laboratory, a mutant defective in the dmcA gene, HL0501, was constructed. The mutant was demonstrated to be defective in chemotaxis toward nutrients. In addition, the methylation profiles of cellular proteins indicated altered MCPs in the mutant relative to those of the parental strain. These results indicate that we have identified an MCP gene in the oral spirochete which plays a significant role in the chemotactic response of the organism.

Amino Acid Sequence↗
PubMed1997

L-allo-threonine aldolase from Aeromonas jandaei DK-39: gene cloning, nucleotide sequencing, and identification of the pyridoxal 5'-phosphate-binding lysine residue by site-directed mutagenesis.

We have isolated the gene encoding L-allo-threonine aldolase (L-allo-TA) from Aeromonas jandaei DK-39, a pyridoxal 5'-phosphate (PLP)-dependent enzyme that stereospecifically catalyzes the interconversion of L-allo-threonine and glycine. The gene contains an open reading frame consisting of 1,014 nucleotides corresponding to 338 amino acid residues. The protein molecular weight was estimated to be 36,294, which is in good agreement with the subunit molecular weight of the enzyme determined by polyacrylamide gel electrophoresis. The enzyme was overexpressed in recombinant Escherichia coli cells and purified to homogeneity by one hydrophobic column chromatography step. The predicted amino acid sequence showed no significant similarity to those of the currently known PLP-dependent enzymes but displayed 40 and 41% identity with those of the hypothetical GLY1 protein of Saccharomyces cerevisiae and the GLY1-like protein of Caenorhabditis elegans, respectively. Accordingly, L-allo-TA might represent a new type of PLP-dependent enzyme. To determine the PLP-binding site of the enzyme, all of the three conserved lysine residues of L-allo-TA were replaced by alanine by site-directed mutagenesis. The purified mutant enzymes, K51A and K224A, showed properties similar to those of the wild type, while the mutant enzyme K199A was catalytically inactive, with corresponding disappearance of the absorption maximum at 420 nm. Thus, Lys199 of L-allo-TA probably functions as an essential catalytic residue forming an internal Schiff base with PLP of the enzyme to catalyze the reversible aldol reaction.

Aeromonas↗
PubMed1997

[Pharmacological studies of BX661A. 5-[4-(2-carboxyethylcarbamoyl)-phenylazo]-salicylic acid disodium salt dihydrate (1). Therapeutic effects on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) model in rats].

In the present study, we investigated the therapeutic effects of 7- or 14-day treatment with BX661A or salazosulfapyridine (SASP) in the DSS-induced UC model in rats. BX661A (10-300 mg/kg, p.o.) dose-dependently decreased the erosion area and the shortening of the large intestine. On the other hand, SASP (30 and 100.mg/kg, p.o.) dose-dependently decreased the erosion area in the treatment for 14 days (on the contrary, % inhibition of erosion area was reduced by the dose of 300 mg/kg), but did not improve the shortening of the large intestine. Secondly, we investigated the therapeutic effects of 5-aminosalicylic acid (5-ASA), 4-aminobenzoyl- beta-alanine (4-ABA) and sulfapyridine (SP) by intrarectal administration on the DSS-induced UC model in rats. 5-ASA significantly decreased the erosion area in the large intestine and improved the length of the large intestine of rats that was shortened by ingesting DSS. On the other hand, 4-ABA and SP improved neither the shortening nor the erosion area of the large intestine. These results suggest that BX661A may be clinically effective and useful in the treatment of patients with ulcerative colitis. Furthermore, it was suggested that 5-ASA may be the active moiety for the therapeutic effects of BX661A and SASP.

Administration, Oral↗
PubMed1997

Inhibition by aminosalicylates of lipid peroxidation in large intestinal mucosa after mesenteric ischemia/reperfusion in the rat.

To clarify the mode of action of aminosalicylates, which are generally used as therapeutic agents for ulcerative colitis, we investigated the effect of some of the aminosalicylates on lipid peroxidation in the large intestinal mucosa after mesenteric ischemia/reperfusion in the rat. Lipid peroxidation was assessed by measuring the level of thiobarbituric-acid-reactive substances. It was found that aminosalicylates dose-dependently inhibited the elevation of the level of thiobarbituric-acid-reactive substances in the large intestinal mucosa after ischemia/reperfusion. This effect may partly contribute to the therapeutic actions of aminosalicylates in ulcerative colitis.

Aminosalicylic Acids↗
PubMed1997

The effects of a newly developed nonsteroidal anti-inflammatory drug (M-5011) on arachidonic acid metabolism in rheumatoid synovial fibroblasts.

M-5011 (d-2-[4-(3-methyl-2-thienyl)phenyl]propionic acid) is a newly developed nonsteroidal anti-inflammatory drug (NSAID) that displays potent anti-inflammatory and analgesic properties with low ulcerogenic activities in animal models. In this study, the effects of M-5011 on arachidonic acid (AA) metabolism in synovial fibroblasts from patients with rheumatoid arthritis were evaluated and compared with those of other NSAIDs in vitro. Either M-5011 or ketoprofen potently inhibited prostaglandin (PG) E2 production by cyclooxygenase (COX)-2 from exogenous AA in interleukin-1beta (IL-1beta)-stimulated cells. The IC50 values of M-5011 and ketoprofen were 4.4 x 10(-7) and 5.9 x 10(-7) M, respectively. However, diclofenac and indomethacin were one order less potent. Although the latter two drugs exhibited time-dependent and irreversible inhibition on COX-2 in IL-1beta-stimulated cells, the inhibitory effects of M-5011 and ketoprofen were reversible. PGE2 production by COX-1 from exogenous AA in non-stimulated cells was also inhibited by M-5011 with a potency less than that of ketoprofen. In addition, M-5011 inhibited [14C]AA release from prelabeled synovial cells stimulated with bradykinin. However, ketoprofen hardly affected the [14C]AA release. It is likely that the effects of M-5011 on AA metabolism are, in part, responsible for its in vivo efficacy and safety profile.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1997

cDNA cloning and gene expression of phenylalanine ammonia-lyase in Lithospermum erythrorhizon.

Two cDNA clones (LEPAL-1 and LEPAL-2) encoding phenylalanine ammonia-lyase were isolated from cell suspension cultures of Lithospermum erythrorhizon. Northern kinetic studies showed that LEPAL-1 mRNA contents markedly increased one day after inoculation of the cells into fresh medium, then decreased to the steady-state level. The course of mRNA accumulation paralleled that of PAL enzyme activity. The rapid induction of PAL activity seems to reflect the induction of dihydroechinofuran biosynthesis, while shikonin was produced at the steady-state level of PAL activity. The course of LEPAL-2 mRNA accumulation seemed to be similar to, but much lower than that of LEPAL-1. In the intact plant, both genes are expressed mainly in the root, the organ in which shikonin is exclusively produced and accumulated. Genomic Southern blot analyses showed that both genes are present in the genome as single copies.

Amino Acid Sequence↗
PubMed1997

Spontaneous remission of desquamative interstitial pneumonia.

We report a case of spontaneous remission of desquamative interstitial pneumonia (DIP) in a 50-year-old male. The histological diagnosis of DIP was based on open lung biopsy. A chest X-ray revealed reticulo-nodular shadows in the bilateral lung fields, and the patient had mild dyspnea on exertion. Without treatment, these shadows decreased gradually and disappeared after several months. The patient recovered completely within one year, and recurrence of the disease has not been observed for 4 years. Recently, DIP has rarely been described, and the spontaneous remission of DIP has not been reported since Carrington et al in 1978 (1).

Biopsy↗
PubMed1997

Giant vascular leiomyoma in the hand.

Vascular leiomyoma or angioleiomyoma is a benign solitary tumour that arises from the mediae layer of the vein walls. It is usually located in the wall of the uterus. We describe a 73-year-old man who presented with a slowly growing mass in the thenar region of his right hand which, on histological examination, was shown to be a giant vascular leiomyoma. This is extremely rare and we could find only about 100 such cases reported in English.

Aged↗
PubMed1997

Hydroxyl radical scavenging activity of nonsteroidal anti-inflammatory drugs.

The hydroxyl radical (.OH)-scavenging activity of d-2-[4-(3-methyl-2-thienyl)phenyl]propionic acid (M-5011), a novel nonsteroidal anti-inflammatory drug (NSAID), and that of several other NSAIDs were investigated by the hyaluronic acid (HA) degradation method and the electron spin resonance (ESR) spin-trapping technique. The superoxide anion (.O2-)-scavenging activity of M-5011 was also measured by the ESR technique. (1) M-5011 and the other NSAIDs examined inhibited the degradation of HA induced by the Fenton reaction system in a dose-dependent manner. (2) M-5011 and the other NSAIDs scavenged .OH directly in a dose-dependent manner. (3) M-5011 was the most potent drug among the NSAIDs tested regarding the scavenging activity of .OH as follows; M-5011 > indomethacin > ketoprofen = suprofen > aspirin. The .OH-scavenging activity of M-5011 was potent in comparison with that of oxidized glutathione (GSSG), an endogenous .OH scavenger. (4) M-5011 did not scavenge .O2-; nor did GSSG. These results suggest that M-5011 acts as a scavenger of .OH at sites with inflammatory lesions.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1997

The multiple roles of macrophage scavenger receptors (MSR) in vivo: resistance to atherosclerosis and susceptibility to infection in MSR knockout mice.

Both type I and type II MSRs are integral membrane proteins containing a collagenous domain and elicit an extraordinarily wide range of ligand binding capability. They were found during the search for the molecule(s) responsible for the accumulation of modified LDL during atherogenesis. However, all prior the evidence relating to their physiological and pathophysiological roles in vivo had been indirect. Targeted disruption of the MSR gene results in a reduction in the size of atherosclerotic lesions in an apo E deficient animal. Macrophages from MSR deficient mice exhibit a marked decrease in modified LDL uptake in vitro, whereas modified LDL clearance from plasma remains normal, suggesting that there are alternative mechanisms for the uptake of modified LDL from the circulation. In addition, MSR knockout mice are more susceptible to L. monocytogenes and HSV-1 infection, indicating a role for MSR in host defense against various pathogens.

Animals↗
PubMed1997

[Juvenile onset of idiopathic interstitial pneumonia].

A 22-year-old first man came to our hospital because of dyspnea on exertion in February 1993, and was admitted in September 1994 because of progression of dyspnea. A chest roentgenogram showed diffuse ground-glass-opacities in the middle and lower lung fields, and an elevated diaphragm. Pulmonary-function testing revealed a low %VC and a low diffusing capacity. Examination of a specimen obtained by thoracoscopic lung biopsy revealed usual interstitial pneumonia. Immunohistochemical examinations showed the expression of intercellular adhesion molecule-1 on vascular endothelial cells and on alveolar epithelial cells. Dust inhalation and collagen vascular disease were ruled out and the diagnosis was idiopathic interstitial pneumonia. This condition develops only rarely in patients under 60 years old.

Adult↗
PubMed1997

[Antitumor effect of S-1 and cisplatin treatment against human gastric cancer xenografted in nude mice].

The enhanced effects due to the combined use of oral administration of S-1 and intraperitoneal administration of Cisplatin (CDDP) were examined with gastric cancer xenografts (NUGC 4). S-1, a new anticancer drug, was daily administered at 10 mg/kg (qld x 5 x 3 weeks). 5-FU level in blood was 1 microgram/ml at two hours after the treatment. Antitumor activity was not found in mice with only the CDDP treatment. But antitumor activity by S-1 and daily low-dose (1 mg/kg) or intermittent treatment (5 mg/kg) of CDDP showed better results than daily S-1 treatment. The daily low-dose CDDP treatment showed similar efficacy to the intermittent administration at the same total dose, but the daily low-dose CDDP treatment was better in the light of toxicities. These results suggest that treatment with S-1 and daily low-dose CDDP was effective for gastric cancer.

Administration, Oral↗
PubMed1997

[Thermoradiotherapy combined with daily administration of low dose cisplatin for locally advanced laryngeal carcinoma].

We applied thermoradiotherapy combined with daily administration of low dose cisplatin (CDDP) to five patients with locally advanced laryngeal carcinoma. The total response rate (CR + PR) was 100% after irradiation of 30 or 40 Gy. One case showed CR, and the larynx could be preserved by adding a full dose of irradiation. CDDP administration was discontinued in two cases due to renal dysfunction or thrombopenia, but other cases tolerated the therapy without severe side effects. Total laryngectomy and bilateral neck dissection was carried out in four cases after irradiation of 30 or 40 Gy. Removed larynxes were prepared for light microscopic observations of the serial sections. One of the four specimens revealed a CR histologically. The combination of thermoradiotherapy with low dose CDDP showed a remarkable effect on reduction of tumor size and cytotoxicity of tumor cells. This might contribute to saving the larynx of patients with locally advanced laryngeal carcinoma.

Aged↗
PubMed1996

Photoreaction cycle of photoactive yellow protein from Ectothiorhodospira halophila studied by low-temperature spectroscopy.

The photocycle of photoactive yellow protein (PYP) from Ectothiorhodospira halophila was studied by low-temperature spectroscopy. Irradiation of PYP at -190 degrees C produced a photo-steady-state mixture composed of bathochromic and hypsochromic photoproducts (PYPB and PYPH). Upon warming, PYPH was thermally converted to a slightly blue-shifted intermediate (PYPHL) above -150 degrees C and then to a red-shifted one (PYPL) above -80 degrees C. PYPB was thermally converted to the blue-shifted intermediate (PYPBL) above -180 degrees C and then to PYPL above -90 degrees C. PYPL thermally reverted to PYP above -50 degrees C, completing the photocycle. The spectral properties of PYPL formed at low temperature suggest that it corresponds to the red-shifted photoproduct detected in the nano- to microsecond time scale at room temperature (A465). The absolute absorption spectra of PYPH, PYPB, and PYPL were estimated, and their absorption maxima were determined to be 442 and 489 nm at -190 degrees C and 456 nm at -80 degrees C, respectively. Although a near-UV intermediate (A355) is observed in the recovery process of PYP from A465 at room temperature, it was not detected at low temperatures, probably due to the effects of temperature and the presence of glycerol. A scheme of the photocycle of PYP is presented.

Bacteria↗
PubMed1996

The methanol-induced globular and expanded denatured states of cytochrome c: a study by CD fluorescence, NMR and small-angle X-ray scattering.

Methanol-induced conformational transitions of cytochrome c(cyt c) at acidic pH values were investigated with a combined use of far and near-UV CD, fluorescence, NMR spectroscopy and small-angle X-ray scattering. At pH 3.0 and 25 degrees C, two methanol-induced non-native states were characterized. First, addition of methanol up to 25% (v/v) induced a compact denatured conformer (I(M)). Further addition of methanol transformed this I(M) state into the expanded and highly helical denatured state (H). The existence of the I(M) state was shown by the discrepancy in transition curves obtained from the ellipticity at 222 nm, the ellipticity at 282 nm, the tryptophan fluorescence monitored at 350 nm and the native peak intensity of the (1)H NMR spectrum. These CD, fluorescence and NMR results showed that the I(M) state has no specific tertiary structure but has a secondary structural content and tryptophan environment similar to those in the native state. The radius of gyration of the I(M) state, 17.7 angstroms, obtained from the Guinier plot of the small-angle X-ray scattering data was significantly smaller than that of the acid-denatured state (30.1 angstroms) and was closer to that of the native state (14.6 angstroms), showing that the I(M) state is compact. The Kratky plot for the I(M) state exhibited a bell-shaped profile, indicating a globular conformation. These structural features indicate that the structure of the I(M) state is quite similar to that of the anion-induced molten globule state of this protein. Furthermore the alcohol-denatured state (H) of cyt C in 60% (v/v) methanol was structurally characterized. Though the H state had a helical content much higher than the native state monitored by far-UV CD spectroscopy, the radius of gyration, 31.7 angstroms, was similar to that of the acid-denatured state, showing that this H state is an expanded denatured state. The Kratky plot for the H state did not show a clear peak, indicating a chain-like conformation. Thus we conclude that the H state has an expanded and chain-like conformation with a high helical content. Finally, we constructed a phase diagram of cyt c involving the native, I(M), acid-denatured and H states against pH and the methanol concentration. The result indicates that the I(M) state is found in the pH range from 2.5 to at least 4.5 with a pH-dependent optimum methanol concentration of 10 to 40%.

Circular Dichroism↗
PubMed1996

Conformational characterization of DnaK and its complexes by small-angle X-ray scattering.

DnaK, a member of the 70 kDa heat shock protein (hsp70) family, and its complexes with substrate proteins and nucleotides were characterized by small-angle X-ray scattering (SAXS) and size-exclusion chromatography (SEC) techniques. The SAXS data indicated that DnaK has a dumbbell-shaped structure with a maximum dimension (dmax) of 112 angstrom, which is consistent with the reported two major functional domains [Chappell et al. (1987) J. Biol. Chem. 268, 12730-12735; Flaherty et al. (1990) Nature 346, 623-628]. The data were best fit by a model in which the two domains either are connected by a short hinge region or are just in contact with each other. The radius of gyration (Rg) of DnaK was determined as 37.5 +/- 1.0 angstrom in the absence of nucleotide. Binding of ATP induces a conformational change in DnaK as reflected by the changes in its P(r) function and Kratky plot, the increases (1-2 angstrom) in both its radius of gyration (Rg) and its Stokes radius (Rs), and the increase in its dmax (5-10 angstrom ). SAXS and SEC-HPLC results indicate that the association state of DnaK is very sensitive to the buffer concentration and the presence of substrates, as well as the protein concentration. At high buffer and protein concentrations, DnaK dimerizes, resulting in an increase in its apparent Rg and dmax values. The addition of substrate (unfolded protein or ATP) results in a return to the Rg value of monomeric DnaK, due to the dissociation of DnaK multimers induced by the substrate binding and resultant conformational changes. The DnaK-substrate protein complex gives a smaller Rg than expected, suggesting that the substrate protein binds to a cavity or cleft on DnaK rather than the exterior of the chaperone. The Kratky plot of the Gdn.HCl-induced unfolding intermediate state of DnaK is consistent with a compact, molten globule-like conformation, as previously suggested based on CD, fluorescence, and SEC-HPLC results [Palleros et al. (I 993) Biochemistry 32, 4314-4321].

Bacterial Proteins↗