In vitro antimicrobial activity of T-91825, a novel anti-MRSA cephalosporin, and in vivo anti-MRSA activity of its prodrug, TAK-599.

TAK-599 is a water-soluble prodrug of a cephalosporin compound, T-91825. In vitro and in vivo antibacterial activities of T-91825 and TAK-599, respectively, were examined. T-91825 was active against both gram-positive and gram-negative bacteria, unlike vancomycin and linezolid, which are inactive against gram-negative bacteria.

Autonomic nervous activity and stress hormones induced by hyperbaric saturation diving.

This study describes the changes in autonomic nervous activity and stress hormones during a hyperbaric saturation dive up to 4.1 MPa in six subjects. Their autonomic nervous activity was assessed by a power spectrum analysis of heart rate variability (HRV).

TAK-599, a novel N-phosphono type prodrug of anti-MRSA cephalosporin T-91825: synthesis, physicochemical and pharmacological properties.

Crystalline 1 (TAK-599) is a novel N-phosphono prodrug of anti-methicillin-resistant Staphylococcus aureus (MRSA) cephalosporin 2a (T-91825) that has high affinity for penicillin-binding protein (PBP) 2' (IC(50); 0.90 microg/mL) and shows potent in vitro anti-MRSA activity (MIC against MRSA N133; 1.56 microg/mL), comparable to that of vancomycin (1.

In vitro and in vivo antifungal activities of TAK-456, a novel oral triazole with a broad antifungal spectrum.

TAK-456 is a novel oral triazole compound with potent and broad-spectrum in vitro antifungal activity and strong in vivo efficacy against Candida albicans and Aspergillus fumigatus. TAK-456 inhibited sterol synthesis of C. albicans and A.

Efficacy of TAK-457, a novel intravenous triazole, against invasive pulmonary Aspergillosis in neutropenic mice.

TAK-457 is an injectable prodrug of TAK-456, which is a novel oral triazole compound with potent antifungal activity. The in vivo efficacy of TAK-457 was evaluated in two models of invasive pulmonary aspergillosis with CDF(1) mice and CBA/J mice with transient neutropenia induced by cyclophosphamide. Against the infection in CDF(1) mice, treatment with 10 mg of TAK-457 and 1 mg of amphotericin B/kg reduced the fungal burden in lungs and rescued all mice.

Inhibitory effects of small-molecule CCR5 antagonists on human immunodeficiency virus type 1 envelope-mediated membrane fusion and viral replication.

We established a human immunodeficiency virus type 1 (HIV-1) envelope (Env)-mediated membrane fusion assay and examined the small-molecule CCR5 antagonist TAK-779 and its derivatives for their inhibitory effects on HIV-1 Env-mediated membrane fusion and viral replication. The membrane fusion assay is based on HIV-1 long terminal repeat-directed beta-D-galactosidase reporter gene expression in CD4- and CCR5-expressed HeLa (MAGI-CCR5) cells after cocultivation with effector 293T cells expressing HIV-1 Env. Inhibition of HIV-1 replication was also determined in MAGI-CCR5 cells infected with the corresponding cell-free HIV-1.

Optically active antifungal azoles. XII. Synthesis and antifungal activity of the water-soluble prodrugs of 1-[(1R,2R)-2-(2,4-difluorophenyl)-2-hydroxy-1-methyl-3-(1H-1,2,4-triazol-1-yl)propyl]-3-[4-(1H-1-tetrazolyl)phenyl]-2-imidazolidinone.

1-[(1R,2R)-2-(2,4-Difluorophenyl)-2-hydroxy-1-methyl-3-(1H-1,2,4-triazol-1-yl)propyl]-3-[4-(1H-1-tetrazolyl)phenyl]-2-imidazolidinone (1: TAK-456) was selected as a candidate for clinical trials, but since its water-solubility was insufficient for an injectable formulation, the quaternary triazolium salts 2 were designed as water-soluble prodrugs. Among the prodrugs prepared, 4-acetoxymethyl-1-[(2R,3R)-2-(2,4-difluorophenyl)-2-hydroxy-3-[2-oxo-3-[4-(1H-1-terazolyl)phenyl]-1-imidazolidinyl]butyl]-1H-1,2,4-triazolium chloride (2a: TAK-457) was selected as an injectable candidate for clinical trials based on the results of evaluations on solubility, stability, hemolytic effect and in vivo antifungal activities.

Studies on anti-MRSA parenteral cephalosporins. IV. A novel water-soluble N-phosphono type prodrug for parental administration.

A systematic approach for improving the water-solubility of anti-MRSA (methicillin-resistant Staphylococcus aureus) cephalosporin derivatives is described. We first tried to improve the water-solubility of 7beta-[2-(5-amino-1,2,4-thiadiazol-3-yl)-2(Z)-fluoromethoxyiminoacetamido]-3-[(E)-2-(1-methylimidazo[1,2-b]pyridazinium-6-yl)thiovinyl]-3-cephem-4-carboxylate (1a) by substitution of the C-3' pharmacophore. Replacement of the C-3' pharmacophore with a 1-methyl-4-pyridinio group improved the water-solubility without decreasing the anti-MRSA activity.

Studies on anti-MRSA parenteral cephalosporins. III. Synthesis and antibacterial activity of 7beta-[2-(5-amino-1,2,4-thiadiazol-3-yl)-2(Z)-alkoxyiminoacetamido-3.

In the course of our exploration for a novel cephalosporin derivative having excellent antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA), we modified the C-3 linked spacers of cephem derivatives bearing a 1-methylimidazo[1,2-b]pyridazinium-6-yl group at the C-3' position and 2-(5-amino-1,2,4-thiadiazol-3-yl)-2(Z)-cyclopentyloxy-iminoacetyl group at the C-7 position. The optimal spacers were the (E)-2-vinyl and (E)-2-thiovinyl groups seen in 19a and 29aa, respectively. Their anti-MRSA activity was 16 to 32 times as potent as that of cefozopran (CZOP).

Optically active antifungal azoles. X. Synthesis and antifungal activity of N.

New optically active antifungal azoles, N-14-(azolyl)phenyl]- and N-14-(azolylmethyl)phenyl]-N'-[(IR,2R)-2(2,4-difluorophenyl)-2-hydroxy-1-methyl-3-(IH-1,2,4-triazol-1-yl)propyllazolones (1, 2, 3), were prepared in a stereocontrolled manner. Compounds 1-3 showed strong antifungal activity against Candida albicans in vitro. Among them, the imidazolidinones 3 showed a broad antifungal spectrum in vitro as well as potent in vivo activity against candidiasis and aspergillosis in mice.

Studies on anti-MRSA parenteral cephalosporins. II. Synthesis and antibacterial activity of 7beta-[2-(5-amino-1,2,4- thiadiazol-3-yl)-2(Z)-alkoxyiminoacetamido]-3-(substituted imidaz.

In an effort to discover a novel cefozopran (CZOP) derivative having excellent antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA), we performed chemical modification of the alkoxyimino moiety and imidazo[1,2-b]pyridazinium group of CZOP. Among the prepared compounds, the cyclopentyloxyimino derivative 7beta-[2-(5-amino-1,2,4-thiadiazol-3-yl)-2(Z)-cyclopentyloxyiminoacetamido]-3-(3,6-diaminoimidazo[1,2-b]pyridazinium-1-yl)methyl-3-cephem-4-carboxylate (20 g) showed the most potent anti-MRSA activity, reflecting its high affinity (IC50 = 1.6 microg/ml) for penicillin binding protein 2' (PBP2'), although its anti-MRSA activity was slightly inferior to that of vancomycin (VCM).

Studies on anti-MRSA parenteral cephalosporins. I. Synthesis and antibacterial activity of 7beta-[2-(5-amino-1,2,4-thiadiazol-3-yl)-2(Z)- hydroxyiminoacetamido]-3-(substituted imidaz.

In order to improve the antibacterial activity of cefozopran (CZOP) against methicillin-resistant Staphylococcus aureus (MRSA), we initiated chemical modification to introduce a 2-(5-amino-1,2,4-thiadiazol-3-yl)-2(Z)-hydroxyimino acetyl group at the C-7 position and a 3- or 6-substituted imidazo[1,2-b]pyridazinium or 5-substituted imidazo[1,2-a]pyridinium group at the C-3' position. Although this approach successfully enhanced the anti-MRSA activity of CZOP two to eight times, a slight decrease in the activity against Gram-negative bacteria including Pseudomonas aeruginosa was involved. Among the novel derivatives, 3-(6-aminoimidazo[1,2-b]pyridazinium-1-yl)methyl-7beta-[2-(5-amino-1,2,4-thiadiazol-3-yl)-2(Z)hydroxyiminoacetamido]-3-cephem-4-carboxylate (44a) showed an excellent balance of activity against MRSA and Gram-negative bacteria.

Establishment of a CCR5-expressing T-lymphoblastoid cell line highly susceptible to R5 HIV type 1.

The beta-chemokine receptor CCR5 is considered to be an attractive target for inhibition of CCR5-using (R5 or macrophage-tropic) HIV-1. However, R5 HIV-1 cannot replicate in CD4+ T cell or monocyte lines because of the lack of CCR5 expression on their surface, which apparently hampers discovery and development of effective CCR5 antagonists against HIV-1 replication. In this study, we have established the CCR5-expressing T cell line MOLT-4/CCR5, highly permissive to the replication of R5 HIV-1.

A small-molecule, nonpeptide CCR5 antagonist with highly potent and selective anti-HIV-1 activity.

The beta-chemokine receptor CCR5 is considered to be an attractive target for inhibition of macrophage-tropic (CCR5-using or R5) HIV-1 replication because individuals having a nonfunctional receptor (a homozygous 32-bp deletion in the CCR5 coding region) are apparently normal but resistant to infection with R5 HIV-1. In this study, we found that TAK-779, a nonpeptide compound with a small molecular weight (Mr 531.13), antagonized the binding of RANTES (regulated on activation, normal T cell expressed and secreted) to CCR5-expressing Chinese hamster ovary cells and blocked CCR5-mediated Ca2+ signaling at nanomolar concentrations.

Formation of azole-resistant Candida albicans by mutation of sterol 14-demethylase P450.

The sterol 14-demethylase P450 (CYP51) of a fluconazole-resistant isolate of Candida albicans, DUMC136, showed reduced susceptibility to this azole but with little change in its catalytic activity. Twelve nucleotide substitutions, resulting in four amino acid changes, were identified in the DUMC136 CYP51 gene in comparison with a reported CYP51 sequence from a wild-type, fluconazole-susceptible C. albicans strain.

Optically active antifungal azoles. VIII. Synthesis and antifungal activity of 1-[(1R,2R)-2-(2,4-difluoro- and 2-fluorophenyl)-2-hydroxy-1-methyl-3-(1H-1,2,4-triazol-1-yl)propyl]- 3-(4-substituted phenyl)-2(1H,3H)-imidazolones and 2-imidazolidinones.

New optically active antifungal azoles, 1-[(1R,2R)-2-(2,4-difluoro- and 2-fluorophenyl)-2-hydroxy-1-methyl-3-(1H-1,2,4-triazol-1-yl)propyl ]-3-(4- substituted phenyl)-2(1H,3H)-imidazolones (1,2) and 2-imidazolidinones (3,4), were prepared in a stereocontrolled manner from (1S)-1-[(2R)-2-(2,4- difluoro- and 2-fluorophenyl)-2-oxiranyl]ethanols (15, 16). Compounds 1-4 showed potent antifungal activity against Candida albicans in vitro and in vivo, as well as a broad antifungal spectrum for various fungi in vitro. Furthermore, the imidazolidinones, 3b--e and 4d, e, were found to exert extremely strong growth-inhibitory activity against Aspergillus fumigatus.

[In vitro specific binding of Shiga toxin 1 and 2 by TAK-751S (Gb3 analog)].

TAK-751S is a synthetic trisaccharide coupled to Chromosorb P using a spacer sequence of 8-methoxycarboyloctyl (MCO). Its chemical structure is similar to a human receptor (Gb3) of Stx produced by enterohemorrhagic Escherichia coli (EHEC). In vitro efficacy of TAK-715S was studied by using ACHN cultured cell assay, which is sensitive and specific for measuring low level of Stx.

In vitro and in vivo efficacy of the triazole TAK-187 against Cryptococcus neoformans.

Multiple isolates of Cryptococcus neoformans, including those with fluconazole resistance, were tested to assess the in vitro activity of the new triazole TAK-187. MICs of TAK-187 were at least eightfold lower than those of fluconazole, and fungicidal concentrations for most isolates were 4 microg/ml or less. TAK-187 also was evaluated as intermittent therapy using two dosages in a rabbit model of experimental cryptococcal meningitis.

Therapeutic efficacy of cefozopran in a murine model of haematogenous pneumococcal meningitis.

Antimicrobial regimens for the treatment of pneumococcal meningitis are not established. We have produced a murine model of haematogenous pneumococcal meningitis and have examined its usefulness for determining the required dosage and term of antimicrobial agents. Streptococcus pneumoniae serotype 6 was injected intraperitoneally (inoculum: about 1 x 10(4) CFU) into mice.

Modified agar dilution susceptibility testing method for determining in vitro activities of antifungal agents, including azole compounds.

In vitro activities of antifungal agents, including azole compounds, against yeasts were easily determined by using RPMI-1640 agar medium and by incubating the plates in the presence of 20% CO2. The end point of inhibition was clear by this method, even in the case of azole compounds, because of the almost complete inhibition of yeast growth at high concentrations which permitted weak growth of some Candida strains by traditional methods. MICs obtained by the agar dilution method were similar to those obtained by the broth dilution method proposed by the National Committee for Clinical Laboratory Standards.

[Possibility of drug design of beta-lactam antibiotics effective for multiresistant gram-positive pathogens].

Since infectious diseases are caused by various bacteria and most of them are treated empirically, broad-spectrum antibiotics are required. To expand the spectrum, an imidazopyridazinium group and aminothiadiazole group were introduced to 3- and 7-side chain of cephem nucleus, respectively. The resulting compound, cefozopran, was able to permeate not only outer membrane of Pseudomonas aeruginosa but also envelope of gram-positive bacteria, which functioned as a barrier to antipseudomonal cephalosporins, and showed potent activity against wide variety of bacteria including those which produced a large amount of cephalosporinase and were resistant to third-generation cephalosporins.

Therapeutic effects of cefozopran against experimental mixed urinary tract infection with Enterococcus faecalis and Pseudomonas aeruginosa in mice.

The therapeutic activity of cefozopran, a new semisynthetic parenteral cephalosporin, was compared with those of ceftazidime, ampicillin, imipenem/cilastatin and ofloxacin against an ascending mixed urinary tract infection induced in mice with Enterococcus faecalis TN2005 and Pseudomonas aeruginosa P9. Cefozopran significantly reduced viable cell counts of both organisms in the kidneys. Ceftazidime, imipenem/cilastatin and ofloxacin were active against only P.

Optically active antifungal azoles. VII. Synthesis and antifungal activity of stereoisomers of 2-[(1R,2R)-2-(2, 4-difluorophenyl)-2-hydroxy-1-methyl-3-(1H-1,2,4-triazol-1-yl) propyl]-4-[4-(2,2,3,3-tetrafluoropropoxy)phenyl]-3(2H,4H)-1,2,4-triazo lone (TAK-187).

2-[(1R,2R)-2-(2,4-Difluorophenyl)-2-hydroxy-1-methyl-3-(1H-1,2, 4-triazol-1-yl)propyl]-4-[4-(2,2,3,3,tetrafluoropropoxy) phenyl]-3(2H, 4H)-1,2,4-triazolone [(1R,2R)-1: TAK-187] is a new antifungal agent selected as a candidate for clinical trials. The three stereoisomers [(1S,2S)-, (1R,2S)- and (1S,2R)-1] of this compound were prepared to clarify the relationship between the stereochemistry and the biological activities. In vitro and in vivo assays of antifungal activity revealed that TAK-187 [(1R,2R)-1] is the most potent among the four stereoisomers.

Gastrointestinal colonization by methicillin-resistant Staphylococcus aureus in immunosuppressed mice.

ICR mice were inoculated intranasally with methicillin-resistant Staphylococcus aureus (MRSA) N133, and the inoculated MRSA was quantitatively recovered from the ceca and feces. The viable counts of the MRSA recovered from ceca correlated well with those from feces. Some mice eliminated MRSA from the cecum by 14 days after inoculation.