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Daisuke Tanaka

Publications and source records attributed to Daisuke Tanaka.

At least 19 recordsLinked to original sources
PubMed2006

Chemical reaction-inspired crystal growth of a coordination polymer toward morphology design and control.

This paper reports a novel crystal growth system of a coordination framework {[Cu3(CN)3{hat-(CN)3(OEt)3}]}n (1) (hat-(CN)3(OEt)3 = 2,6,10-tricyano-3,7,11-triethoxy-1,4,5,8,9,12-hexaazatriphenylene). The coordination polymer is crystallized through the reaction of 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (hat-(CN)6), ethanol, and copper(I) complex, involving the breaking and forming of covalent bonds. The crystal morphologies obtained in the present system contain dumbbells, cogwheels, and superlattices. Moreover, in the growth perpendicular to the c-axis, periodic ramification at regular interval is observed, affording superlattice morphologies. Observation of the growth of dumbbell crystals shows that the growth rates parallel and perpendicular to the crystallographic c-axis are quite different: the former shows a drastic change with the reaction duration, while the latter is almost constant. These results are reproduced as a simple reaction-diffusion system, indicating that chemical reactions on crystal surfaces play an important role in determining the macroscopic crystal morphologies.

Journal Article↗
PubMed2006

Flexible and shape-selective guest binding at Cu(II) axial sites in 1-dimensional Cu(II)-1,2-bis(4-pyridyl)ethane coordination polymers.

A series of guest-binding Cu(II) coordination polymers, {[Cu(bpetha)2(acetone)2].2PF6}n (bpetha = 1,2-bis(4-pyridyl)ethane) (1), {[Cu(bpetha)2(DMF)2].2PF6}n (2), {[Cu(bpetha)(2)(MeCN)(2)].2PF6.2MeCN}n (3), {[Cu(bpetha)2(H2O)2].2PF6.3THF.2H2O}n (4), {[Cu(bpetha)2(H2O)2].2PF6.3dioxane}n (5), and {[Cu(bpetha)2(H2O)2].2PF6.2-PrOH.2H2O}n (6), have been synthesized and crystallographically characterized. Their framework stabilities and guest-exchange properties have also been investigated. All compounds form a similar framework motif, a "double chain", in which the bpetha ligands bridge Cu(II) centers to form 1-D [Cu(bpetha)2]n double chains. A variety of Lewis base guest molecules, such as H2O, acetone, DMF, MeCN, THF, dioxane, and 2-PrOH, are incorporated into the assembly of the 1-D double chains. These chains flexibly change their forms of assembly in a guest-dependent manner. Interestingly, acetone, DMF, and MeCN guests with a carbonyl or cyanide group coordinate directly to the axial sites of the Cu(II) centers; in contrast, THF, dioxane, and 2-PrOH guests with an ether or alcohol group are incorporated into the frameworks not via coordination bonds but via weak interactions (hydrogen bonds and van der Waals forces). This selectivity is probably due to steric effects at coordinated oxygen or nitrogen atoms of the guests. Crystal-to-crystal transformations triggered by guests are observed, during which guests coordinated to the Cu(II) axial sites are readily removed and replaced by other guests.

Journal Article↗
PubMed2006

Essential role of neutrophils in anti-type II collagen antibody and lipopolysaccharide-induced arthritis.

In mice arthritis model induced by anti-type II collagen (CII) antibodies and lipopolysaccharide (LPS), most of cells that infiltrated into the joint space were neutrophils. To investigate the role of neutrophils in the pathogenesis of arthritis, we depleted the neutrophils in vivo by injection of the antibody against Gr-1 expressed mainly on neutrophils. The neutrophil depletion completely inhibited the arthritis development. Furthermore, neutrophil depletion in mice that had already developed arthritis ameliorated the disease. These results showed that neutrophils are indispensable not only for the development, but also for the maintenance of arthritis. Next, we tried to develop arthritis in C5-deficient mice to investigate the involvement of C5a, one of chemotactic factors for neutrophils. C5-deficient mice showed significant reduction in arthritis development in comparison with wild type mice. Injection of pertussis toxin (Ptx) into the mice, which inhibits the signals from the inhibitory G-protein coupled-receptors including the C5a receptor, suppressed the development of arthritis. Furthermore, Ptx also ameliorated the arthritis when injected into mice that had already developed the disease. These results suggest the important role of chemotactic factors involving C5a and inhibitory G-protein (Gi)-coupled receptors not only in the development, but also in the maintenance of arthritis.

Animals↗
PubMed2006

Immobilization of sodium ions on the pore surface of a porous coordination polymer.

A porous coordination polymer (PCP) with immobilization of sodium cations on the pore surface has been synthesized, by employing a bifunctional carboxylate/sulfonate ligand, and structurally characterized. The porous framework with 1D channels of the dimension of 4.9 x 4.9 A2 shows high thermal stability ( approximately 330 degrees C), affording Type I adsorption isotherms for CO2, acetone, and benzene. The chemical shift of 13C NMR and characteristic adsorption energy (betaE0) of acetone adsorbed in this compound represent the Lewis acidity of this framework.

Journal Article↗
PubMed2006

Syntheses of glucose derivatives of E5564-related compounds and their LPS-antagonistic activities.

Glucose analogues 6, 12, 17b, 19a, and 19b of E5564 were synthesized, and their LPS-antagonistic activities were measured. The antagonistic activities (IC(50)) on LPS-induced TNFalpha production of these five compounds toward human whole blood were 72.8, 3.0, 0.9, 7.5, and 1.4nM, respectively. Inhibitory doses (ID(50)) of compounds 12, 17b, 19a, and 19b on TNFalpha production induced by co-injection of galactosamine and LPS in C3H/HeN mice in vivo were measured. The values of these compounds were 0.9, ND (not determined), 1.6, and 0.9mg/kg, respectively.

Animals↗
PubMed2006

Syntheses of glucose analogues of E5564 as a highly potent anti-sepsis drug candidate.

Glucose analogues 5 and 9 of E5564 were synthesized, and their LPS-antagonistic activities were measured. The inhibitory activities (IC50) on LPS-induced TNFalpha production of these two compounds towards human whole blood cells were 0.06 and 0.83 nM, respectively. Inhibitory doses (ID50) of compounds 5 and 9 on TNFalpha production induced by coinjection of galactosamine and LPS in C3H/HeN mice in vivo were measured and were 0.55 and <0.20 mg/kg, respectively. And also C3H/HeN mice preinjected with compounds 5 and 9 were protected from lethality induced by coinjection of galactosamine and LPS; out of eight mice preinjected with 1 mg/kg of the compounds, one-six and three of eight mice were protected, respectively.

Animals↗
PubMed2006

[Mutations of gyrA gene and parC gene in fluoroquinolone-resistant Escherichia coli isolates from sporadic diarrheal cases].

We studied 107 isolates of Escherichia coli O153 from sporadic diarrhea cases in Fukui, Toyama, Aichi, and Saga prefectures from 1991 to 2005 for antimicrobial susceptibility and mechanisms of fluoroquinolone resistance, based on standard disk diffusion. Of 12 drugs tested, ampicillin displayed resistance to 72.9% of isolates, streptomycin to 48.6%, tetracycline to 46.7%, sulfisoxazole to 46.7%, trimethoprim/sulfamethoxazole to 29.9%, nalidixic acid (NA) to 29.9%, and ciprofloxacin (CPFX) to 24.3%. Ten of 32 isolates resistant to 3-6 drugs and 16 of 18 isolates resistant to 7-10 drugs were resistant both to NA and CPFX. Mutations of amino acid in quinolone resistance-determining regions of gyrA and parC genes were detected in 24 isolates resistant both to NA and CPFX, and in 1 isolate resistant to NA. The former possessed a combination of double substitution (S83L and D87L) in GyrA and a single substitution (S80I) in ParC. Some 12 of 24 isolates possessed another single substitution (E84V or E84G or A108T) in ParC. The 25 isolates were classified into 4 types as follows. 1 isolate as type 1: GyrA (S83L) and ParC (S80I); 12 isolates as type 2: GyrA (S83L and D87N) and ParC (S80I); 8 isolates as type 3: GyrA (S83L and D87N) and ParC (S80I and E84G/S80R and E84V); and 4 isolate as type 4: GyrA (S83L and D87N) and ParC (S80I and A108T). In the relationship between amino acid mutations and minimal inhibitory concentrations (MIC) of fluoroquinolone, MICs of CPFX, ofloxacin, and norfloxacin showed 1microg/mL, 2microg/mL and 8microg/mL in type 1; 8 approximately 32microg/mL, 8 approximately 32microg/mL and 16 approximately 256microg/mL in type 2; and 32 approximately 256microg/mL' 32 approximately 128microg/mL and 128-->512microg/ mL in types 3 and 4. These results suggest that most of multiple-antimicrobial-resitant E. coli O153 isolates from sporadic diarrhea cases were resistant to fluoroquinolones and possessed mutations at gyrA and parC genes associated with fluoroquinolone resistance.

DNA Gyrase↗
PubMed2006

Surveillance of group B streptococcal toxic shock-like syndrome in nonpregnant adults and characterization of the strains in Japan.

Nine group B streptococci (GBS) strains were isolated from five toxic shock-like syndrome cases of nonpregnant adults in Japan from 2001 to 2005. All of them were identified as Streptococcus agalactiae. The serotypes of these strains were Ib, III, V, and VII. Pulsed-field gel electrophoresis revealed that the patterns of the strains isolated from the different patients were variable. Antimicrobial susceptibility tests showed that all of the strains were susceptible to penicillin G, ampicillin, cefotaxime, clindamycin, and telithromycin. One strain showed intermediate resistance to erythromycin.

Aged↗
PubMed2005

On the mechanism of the palladium(II)-catalyzed decarboxylative olefination of arene carboxylic acids. Crystallographic characterization of non-phosphine palladium(II) intermediates and observation of their stepwise transformation in Heck-like processes.

Mechanistic studies of a palladium-mediated decarboxylative olefination of arene carboxylic acids are presented, providing spectroscopic and, in two instances, crystallographic evidence for intermediates in a proposed stepwise process. Sequentially, the proposed pathway involves carboxyl exchange between palladium(II) bis(trifluoroacetate) and an arene carboxylic acid substrate, rate-determining decarboxylation to form an arylpalladium(II) trifluoroacetate intermediate (containing two trans-disposed S-bound dimethyl sulfoxide ligands in a crystallographically characterized form), then olefin insertion and beta-hydride elimination. Because of the unique mode of generation of the arylpalladium(II) trifluoroacetate intermediate, a species believed to be substantially electron-deficient relative to phosphine-containing arylpalladium(II) complexes previously studied, it has been possible to gain new insights into those steps that are common to the Heck reaction, namely, olefin insertion and beta-hydride elimination. The present results show that there are notable differences in reactivity between arylpalladium(II) intermediates generated by decarboxylative palladation and those produced in conventional Heck reactions. Specifically, we have found that more electron-rich alkenes react preferentially with an arylpalladium(II) trifluoroacetate intermediate formed by decarboxylative palladation, whereas an opposite trend is found in conventional Heck reactions. In addition, we have found that the aralkylpalladium(II) trifluoroacetate intermediates that are formed upon olefin insertion in the present study are stabilized with respect to beta-hydride elimination as compared to the corresponding phosphine-ligated aralkylpalladium(II) complexes. We have also crystallographically characterized an aralkylpalladium(II) trifluoroacetate intermediate derived from arylpalladium(II) insertion into norbornene, and this structure, too, contains an S-bound dimethyl sulfoxide ligand; the ipso-carbon of the transferred aryl group and trifluoroacetate function as the third and fourth ligands in the observed distorted square-planar palladium(II) complex.

Journal Article↗
PubMed2005

Use of duplex PCR-CTPP methods for CYP2E1RsaI/IL-2 T-330G and IL-1B C-31T/TNF-A T-1031C polymorphisms.

BACKGROUND: Two duplex polymerase chain reaction (PCR) with confronting two-pair primer (PCR-CTPP) methods were designed for cytochrome P450 (CYP) 2E1 RsaI and interleukin (IL-2) T-330G, and for IL-1B C-31T and tumor necrosis factor-alpha (TNF-A) T-1031C. The four polymorphisms are considered to be functional, and the three cytokines reportedly inhibit CYP2E1 expression. Many studies have reported associations between the above polymorphisms and risk of diseases including cancers and inflammatory diseases. AIM: The main objective of this study was to examine the applicability of the established PCR conditions to a real situation. PARTICIPANTS: Participants were female examinees aged from 35 to 85 years who attended health checks run by a local government in Japan. RESULTS: The allele frequencies among 325 female health check examinees were 0.804 for CYP2E1 c1 allele, 0.668 for IL-2-330T allele, 0.554 for IL-1B-31T allele, and 0.822 for TNF-A-1031T allele. p-Values from a Hardy-Weinberg equilibrium test were 0.658, 0.955, 0.062, and 0.806, respectively. DISCUSSION: Clear DNA bands observed with electrophoresis allowed us to genotype the four polymorphisms. The genotype frequencies were within the Hardy-Weinberg equilibrium test proportions, though the p-value for IL-1B C-31T was marginal. CONCLUSIONS: Both duplex PCR-CTPP methods may be useful tools for studies on the association between these polymorphisms and disease risk.

Adult↗
PubMed2005

Molecular mechanisms of high level tetracycline-resistance in group A streptococcal isolates, T serotypes 4 and 11.

The molecular mechanism of high level tetracycline resistance in T serotypes 4 and 11 group A streptococcal (GAS) isolates was examined in 61 tetracycline-resistant isolates in Japan. PCR and sequencing analyses revealed that the T serotype/emm genotype, T4/4 isolates carried tet(O) genes, which were genetically homogenous. The T11/11 and T11/89 isolates carried different subtypes of tet(M) genes, which were present on transposons Tn916 and Tn1545, respectively. In addition, these T11 isolates may have obtained the tet(M) gene after the 1990s, because resistance to tetracycline in T11 isolates was rarely found before then. These results strongly suggested that the T4 and T11 GAS isolates acquired tetracycline-resistance via different molecular mechanisms.

Bacterial Proteins↗
PubMed2005

Close correlation of streptococcal DNase B (sdaB) alleles with emm genotypes in Streptococcus pyogenes.

DNase B is a major nuclease and a possible virulence factor in Streptococcus pyogenes. The allelic diversity of streptococcal DNase B (sdaB) gene was investigated in 83 strains with 14 emm genotypes. Of the 15 alleles identified, 11 alleles carried only synonymous nucleotide substitutions. On the other hand, 4 alleles had a non-synonymous substitution other than synonymous substitutions, resulting in the substitution of a single amino acid. The distribution of each allele was generally emm genotype-specific. Only sdaB7 was found in both emm2 and emm4. The promoter region was highly conserved and DNase B protein was similarly expressed in all alleles.

Alleles↗
PubMed2005

Rapid categorization of pathogenic Escherichia coli by multiplex PCR.

A one-shot multiplex polymerase chain reaction (PCR) was developed for detecting 12 virulence genes of diarrheagenic Escherichia coli. In order to differentiate between the five categories of diarrheagenic E. coli, we selected the target genes: stx1, stx2, and eaeA for enterohemorrhagic E. coli(EHEC); eaeA, bfpA, and EAF for enteropathogenic E. coli(EPEC); invE for enteroinvasive E. coli(EIEC); elt, estp, and esth for enterotoxigenic E. coli(ETEC); CVD432 and aggR for enteroaggregative E. coli(EAggEC); and astA distributed over the categories of diarrheagenic E. coli. In our multiplex PCR system, all 12 targeted genes (stx1, stx2, eaeA, invE, elt, estp, astA, esth, bfpA, aggR, EAF, and CVD432) were amplified in a single PCR reaction in one tube and detected by electrophoresis. Using our multiplex PCR, the 208 clinically isolated strains of diarrheagenic E. coli in our laboratory were successfully categorized and easily analyzed for the presence of virulence plasmids.

Escherichia coli↗