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Biomedical subjects

Y Tomii

Publications and source records attributed to Y Tomii.

At least 19 recordsLinked to original sources
PubMed2006

Observation and control of transverse energy-transport barrier due to the formation of an energetic-electron layer with sheared ExB flow.

Off-axis electron-cyclotron heating in an axisymmetric barrier mirror produces a cylindrical layer with energetic electrons, which flow through the central cell and into the end region. The layer, producing a localized bumped ambipolar potential Phi(C), forms a strong shear of radial electric fields E(r) and peaked vorticity with the direction reversal of E(r)xB sheared flow near the Phi(C) peak. Intermittent vortexlike turbulent structures near the layer are suppressed in the central cell by this actively produced transverse energy-transport barrier; this results in T(e) and T(i) rises surrounded by the layer.

Journal Article↗
PubMed2005

Observation of the effects of radially sheared electric fields on the suppression of turbulent vortex structures and the associated transverse loss in GAMMA 10.

Vortexlike turbulent structures in hot-ion mode plasmas with several keV are observed in the case with a radially produced weak shear of electric fields E(r). However, a strong E(r) shear formation due to a high ion-confining potential phi(c) production clears up these vortices together with plasma-confinement improvement and disappearance of both drift-wave and turbulencelike Fourier spectral signals. These findings are based on three-time progress in phi(c) in comparison to phi(c) attained 1992-2002. The significant advance of phi(c) is well extended in line with proposed potential-formation physics scalings.

Journal Article↗
PubMed2001

Interleukin 10 expression is correlated with thrombospondin expression and decreased vascular involvement in colon cancer.

Interleukin 10 (IL-10) is an immuno-suppressive cytokine produced by T-lymphocytes, and a regulatory molecule for angiogenesis in various cancers. We examined IL-10 gene expression in 53 colon cancer patients who underwent surgical resection. IL-10 gene expression was correlated with TSP1 and TSP2 gene expression (P=0.0049, P=0.0285). Colon cancer with IL-10 gene expression (19/53) showed significantly decreased venous involvement (P=0.0433). The mean vessel counts in the colon cancers with IL-10 gene expression were significantly lower than those without IL-10 gene expression (P<0.001). These results suggested that IL-10 stimulates angiostatic factor gene expression, and results in suppression of venous involvement.

Adenocarcinoma↗
PubMed2000

Ribozyme approach to downregulate vascular endothelial growth factor (VEGF) 189 expression in non-small cell lung cancer (NSCLC).

The aim of this study was to further clarify the role of the cell-associated isoform of vascular endothelial growth factor (VEGF189) on tumour growth and vascularity. Five isoforms of VEGF have been identified with different biological activities. VEGF121, VEGF145, VEGF165, VEGF189, VEGF206 are generated by alternative splicing. We used a hammerhead-type ribozyme (V189Rz) to suppress VEGF189 mRNA. The V189Rz specifically cleaved exon 6 of VEGF189 mRNA, but showed no activity against the VEGF121 or VEGF165 isoforms. The V189Rz was introduced into the human non-small cell lung cancer (NSCLC) cell line (OZ-6/VR). The expression level of VEGF189 mRNA was decreased in the OZ-6/VR cells, while VEGF121 and 165 expression was unaltered. The OZ-6/VR cells xenotransplanted into nude mice showed markedly reduced vascularisation and growth, whereas the cell line did not show any decreased growth under tissue culture conditions. The OZ-6/VR cells (1 x 10(5) cells/mouse) formed no tumours, whereas the parental OZ-6 cells formed large tumours within 8 weeks. The specific suppression of VEGF189 by the ribozyme decreased vascularity and xenotransplantability of the lung cancer cell line. Thus, the cell-associated isoform of VEGF, VEGF189, might have a key role in stromal vascularisation and the growth of NSCLC xenografts in vivo.

Animals↗
PubMed2000

Hammerhead ribozyme specifically inhibits vascular endothelial growth factor gene expression in a human hepatocellular carcinoma cell line.

Hammerhead-type ribozymes are often utilized to suppress the expression of target genes. We evaluated the efficacy of an anti-vascular endothelial growth factor (VEGF) hammerhead-type ribozyme against GUC at exon 1 of the VEGF gene in a cell-free system (in vitro) as well as in the hepatocellular carcinoma cell line HLF (in vivo). The anti-VEGF ribozyme (alphaVRz) specifically cleaved synthetic VEGF RNA substrate, but not other triplet sequences of VEGF RNA substrate in vitro. When the alphaVRz was introduced into HLF cells, the ribozyme suppressed not only VEGF mRNA level but also that of VEGF protein. These results suggest that this ribozyme selectively inhibits VEGF gene expression in human hepatocellular carcinoma cells.

Base Sequence↗
PubMed1999

In vitro and in vivo activities of NS-718, a new lipid nanosphere incorporating amphotericin B, against Aspergillus fumigatus.

We evaluated the in vitro and in vivo potencies of a new lipid nanosphere that incorporates amphotericin B (AmB), NS-718, against Aspergillus fumigatus. The in vitro activity of NS-718 (the MIC at which 90% of strains are inhibited [MIC90], 0.25 microgram/ml) against 18 isolates of A. fumigatus was similar to that of deoxycholate AmB (D-AmB; Fungizone; MIC90, 0.25 microgram/ml), but NS-718 was more potent than liposomal AmB (L-AmB; AmBi-some; MIC90, 1.0 microgram/ml). The in vivo efficacy of NS-718 in a rat model of invasive pulmonary aspergillosis was compared with those of D-AmB and L-AmB. A low dose (1 mg/kg of body weight) of L-AmB was ineffective (survival rate, 0%), although equivalent doses of D-AmB and NS-718 were more effective (survival rate, 17%). However, a higher dose of NS-718 (3 mg/kg) was more effective (survival rate, 100%) than equivalent doses of D-AmB and L-AmB (survival rate, 0%). To explain these differences, pharmacokinetic studies showed higher concentrations of AmB in the plasma of rats treated with NS-718 than in the plasma of those treated with D-AmB. Our results suggest that NS-718, a new preparation of AmB, is a promising antifungal agent with activity against pulmonary aspergillosis.

Amphotericin B↗
PubMed1999

Synthesis and antibacterial activity of novel 7-substituted-6-fluoro-1- fluoromethyl-4-oxo-4H-[1,3thiazeto[3,2-a]quinoline-3-carboxylic acid derivatives.

A series of 7-substituted-6-fluoro-1-fluoromethyl-4-oxo-4H- [1,3]thiazeto[3,2-a]quinoline-3-carboxylic acid derivatives (2a-1) was prepared and evaluated for antibacterial activity. These compounds were obtained by deacylation of 4-benzoyloxy-2-(1-chloro-2-fluoroethyl)thio-6,7- difluoroquinoline-3-carboxylate (10) and subsequent intramolecular cyclization followed by substitution with cyclic amines and then hydrolysis. The intramolecular cyclization reaction of 18, one of the diastereomers (17, 18) revealed that the cyclization reaction proceeded through an inversion to afford (-)-11a in good chemical and optical yield. The enantiomers of 2a were prepared from the enantiomers of 11a, which were obtained by the optical resolution of the racemate using high-performance liquid chromatography (HPLC). Compounds 2a,b showed excellent in vitro and in vivo antibacterial activity against both gram-negative and gram-positive bacteria including quinolone and Methicillin-resistant Staphylococcus aureus.

Animals↗
PubMed1996

Uptake and intracellular activity of NM394, a new quinolone, in human polymorphonuclear leukocytes.

The uptake of NM394, a new quinolone, by and its subsequent elution from human polymorphonuclear leukocytes were studied and compared with those of ofloxacin and ciprofloxacin. The kinetics of the uptake of NM394 was similar to that of ciprofloxacin. The maximum intracellular-to-extracellular concentration ratio was 12.3, compared with 8.6 for ciprofloxacin and 4.9 for ofloxacin at the extracellular concentration of 20 micrograms/ml. The elution of NM394 from human polymorphonuclear leukocytes occurs relatively slowly; 5 min after the removal of extracellular NM394, nearly 100% still remained in polymorphonuclear leukocytes, compared with ofloxacin, which was so rapidly eluted that only 12% remained. The uptake of NM394 was significantly decreased at 4 degrees C and by the presence of NaCN but was not affected by the presence of L-glycine, L-leucine, L-serine, adenosine, or NaF. NM394 showed intracellular activity at a concentration of 0.1 microgram/ml that significantly reduced the number of phagocytosed Pseudomonas aeruginosa cells with 2 h of incubation. These results suggest that uptake of NM394 by human polymorphonuclear leukocytes occurs via an active transport system differing from that of ofloxacin, whose uptake is affected by the presence of L-glycine and L-leucine, and that once accumulated, NM394 remains intracellularly active and participates in protection against bacterial infection.

Amino Acids↗
PubMed1996

Structure-antibacterial activity and cytotoxicity relationships of thiazolo and thiazetoquinolone derivatives.

In the course of our search for derivatives with potent antibacterial activity and low cytotoxicity, we have studied the relationships among the structure, antibacterial activity and cytotoxicity of thiazoloquinolone and thiazetoquinolone derivatives (the term quinolone as used in this paper includes the quinolone, 1,8-naphthyridine and pyridopyrimidine nuclei). The antibacterial activities and cytotoxicity of these derivatives were compared with those of norfloxacin, ofloxacin, enoxacin and ciprofloxacin. The antibacterial activities of the thiazoloquinolone derivatives were more potent than those of the dihyrothiazoloquinolone derivatives, and comparable to that of ciprofloxacin. All of the thiazoloquinolone derivatives were highly cytotoxic against mammalian cells, but some of the dihyrothiazoloquinolone derivatives were less cytotoxic, being comparable in cytotoxicity to the reference drugs. The thiazetoquinolone derivatives were less cytotoxic than the thiazoloquinolone derivatives, and one of them, 6-fluoro-1-methyl-4-oxo-7-(1-piperazinyl)-4H-[1,3]thiazeto[3,2-a] quinoline-3-carboxylic acid, showed the most potent antibacterial activity of all compounds tested in this study, as well as a very low cytotoxicity. The antibacterial activity and cytotoxicity of this compound were similar to that of ciprofloxacin.

4-Quinolones↗
PubMed1996

Therapeutic effect of the quinolone prodrug prulifloxacin against experimental urinary tract infections in mice.

The in vitro antibacterial activity of prulifloxacin (CAS 123447-62-1, NM441), a new quinoline prodrug, against clinical isolates from urinary tract infections was investigated. In addition, it was compared with ofloxacin (CAS 82419-36-1), levofloxacin (CAS 100986-85-4), ciprofloxacin urinary tract infections in mice, as well as its pharmacokinetics. 1. The antibacterial activity of NM394 (6-fluoro-1-methyl-4-oxo-7-(1-piperazinyl)-4H-[1,3]thiazeto[3,2- a]quinoline-3-carboxylic acid), an active metabolite of prulifloxacin, against gram-positive clinical isolates was inferior to that of levofloxacin and tosufloxacin, and equal to that of ofloxacin and ciprofloxacin. Against gram-negative clinical isolates, the activity of NM394 was superior to that of the reference drugs. 2. The therapeutic effect of prulifloxacin on experimental urinary tract infection with Escherichia coli in mice was equal to that of tosufloxacin and ciprofloxacin and superior to that of ofloxacin and levofloxacin. Its therapeutic effect on Pseudomonas aeruginosa infection was equal to that of tosufloxacin and ciprofloxacin, and superior to that of ofloxacin. Against urinary tract infection with olfloxacin-resistant Enterobacter cloacae, prulifloxacin was the most effective of all the drugs tested. 3. The maximal serum concentration of prulifloxacin was slightly higher than that of ciprofloxacin, and the area under the curve (AUC) for prulifloxacin was 1/4 that of ofloxacin, levofloxacin and tosufloxacin. The maximal concentration and AUC of prulifloxacin in lung and kidney were slightly higher than the corresponding values for ciprofloxacin but only 1/2 to 1/4 of the values for ofloxacin, levofloxacin and tosufloxacin. In conclusion, prulifloxacin (NM394) showed potent antibacterial activity against clinical isolates and potent therapeutic efficacy against experimental infection in spite of its lower AUCs compared with the reference drugs. These findings suggest that prulifloxacin may be a useful drug in the treatment of urinary tract infections.

Animals↗
PubMed1995

Studies on pyridonecarboxylic acids. IV. Synthesis and antibacterial activity evaluation of S-(-)- and R-(+)-6-fluoro-1-methyl-4-oxo-7- (1-piperazinyl)-4H-[1,3] thiazeto[3,2-a]quinoline-3-carboxylic acids.

Optically active isomers of 6-fluoro-1-methyl-4-oxo-7-(1-piperazinyl)-4H- [1,3] thiazeto [3,2-alpha] quinoline-3- carboxylic acid (NM394, 3) were prepared through optical resolution of their racemic intermediate ( +/- )-1 by high-performance liquid chromatography (HPLC). The absolute configuration at the C-1 position in the thiazeto-quinolone ring of ( - )-3 was confirmed by X-ray analysis ( - )-4 to be S. The in vitro antibacterial activity of ( - )-3 was 2--8 times that of (+)-3.

Anti-Infective Agents↗
PubMed1995

Studies on pyridonecarboxylic acids. III. Synthesis and antibacterial activity evaluation of 1,8-disubstituted 6-fluoro-4-oxo-7-piperazinyl-4H-[1,3]thiazeto[3,2- a]quinoline-3-carboxylic acid derivatives.

A series of 1,8-disubstituted 6-fluoro-4-oxo-7-piperazinyl-4H-[1,3]thiazeto[3,2-a]quinoline-3- carboxylic acid derivatives was prepared and evaluated for antibacterial activity. In the 7-piperazinyl series, addition of a fluorine at C-8, which increased the in vitro activity for the 1-hydrogen and 1-methyl analogues and decreased it for the 1-phenyl analogue, improved the in vivo activity of all the analogues. Introduction of a methoxy group at C-8 of the 1-methyl-7-piperazinyl analogue also improved its in vivo antibacterial activity. The effect of 8-substituents on the in vitro and in vivo antibacterial activity of the 1-methyl-7-(4-methyl-1-piperazinyl) series is also discussed.

Animals↗
PubMed1992

Studies on pyridonecarboxylic acids. 1. Synthesis and antibacterial evaluation of 7-substituted-6-halo-4-oxo-4H-[1,3]thiazeto[3,2-a]quinoline-3- carboxylic acids.

A series of [1,3]thiazeto[3,2-a]quinoline-3-carboxylic acids and their esters were prepared and evaluated for antibacterial activity. The derivatives with a hydrogen or methyl group at C-1, fluorine at C-6, and piperazinyl or 4-methyl-1-piperazinyl group at C-7 showed superior in vitro antibacterial activity, and the derivatives with 4-methyl-1-piperazinyl group at C-7 had potent in vivo activity. Compound 29a (NM394) showed excellent in vitro antibacterial activity and low toxicity but poor absorption from the gastrointestinal tract. Compound 29ee (NM441), an N-[(5-methyl-2-oxo-1,3-dioxol-4-yl)methyl] derivative of 29a, was found to possess a favorable pharmacokinetic profile and oral activity superior to that of ciprofloxacin in experimental animals.

Administration, Oral↗
PubMed1991

In vitro antibacterial activity of a new quinolone, NM394.

NM394 is a new 6-fluoroquinolone antibacterial agent with a tricyclic structure which has a bridge that connects the N-1 and C-2 positions of the quinolone. The antibacterial activity of NM394 against clinical isolates of staphylococci, streptococci, enterococci, members of the family Enterobacteriaceae, and Pseudomonas aeruginosa was equal to or one-half that of ciprofloxacin. NM394 was as active as ofloxacin against gram-positive bacteria and was two to eight times more active against gram-negative bacteria, including P. aeruginosa. NM394 was two to eight times more active than enoxacin against gram-positive and gram-negative bacteria. The MICs of NM394 against Escherichia coli and P. aeruginosa at pH 5.5 were reduced 4 to 16 times compared with those at pH 7.0. Ciprofloxacin, ofloxacin, and enoxacin were 2 to 32 times less active against these two bacteria and Staphylococcus aureus at an acidic pH than they were at pH 7.0. In the presence of 5 mM Mg2+, the MICs of all of these drugs increased 2 to 32 times, but they were only slightly affected by 5 mM Ca2+, type of medium, serum, or size of inoculum. NM394 showed potent bactericidal activity and inhibited the supercoiling activity of E. coli DNA gyrase. The in vitro antibacterial profile of NM394 is similar to that of other 6-fluoroquinolones.

Anti-Infective Agents↗
PubMed1991

In vivo evaluation of NM441, a new thiazeto-quinoline derivative.

NM441 is a lipophilic prodrug of a new thiazeto-quinoline carboxylic acid derivative NM394, and when it is administered orally it is readily absorbed and hydrolyzed to its parent compound. After oral administration of NM441 at a dose of 20 mg/kg to dogs, the peak concentration of NM394 in plasma was 2.39 micrograms/ml, whereas it was 0.63 micrograms/ml for NM394 administered alone. The in vivo activity of NM441 was compared with those of ciprofloxacin, ofloxacin, and enoxacin in mouse protection studies. NM441 was as effective as ofloxacin and was twice as effective as ciprofloxacin against systemic infection with Staphylococcus aureus. Against infections with streptococci, NM441 was two to three times as effective as ofloxacin and five times as effective as ciprofloxacin. Against infection with Escherichia coli, NM441 was as effective as ciprofloxacin and ofloxacin, but against infections with Klebsiella pneumoniae, Serratia marcescens, and Pseudomonas aeruginosa, NM441 was two to four times as effective as ciprofloxacin and ofloxacin. NM441 was three to seven times as effective as enoxacin in systemic infections. Against urinary tract infections with E. coli, NM441 reduced the number of bacterial CFU per gram of kidney by 1 to 2 log10 more and, with P. aeruginosa, by 1 to 6 log10 more than did ciprofloxacin and ofloxacin. Against respiratory tract infections with K. pneumoniae, NM441 was as effective as ofloxacin and was twice as effective as ciprofloxacin.

Administration, Oral↗
PubMed1976

Preventive procedure of dysuria after radical hysterectomy by adnexal flap fixation to the bladder.

To prevent postoperative dysuria, which occurs inevitably after the radical hysterectomy, several surgical procedures have been tried. The principal method is to suture adnexal flaps to the bladder trigone and fundus. Of four procedures so far tried sequentially, the best one was to fix the bladder trigone and to support it with round ligament flaps sutured with the bladder fundus covered by tubal flaps (Type IV). In follow-up studies, Type IV proved more preferable than the other three types or the non-sutured control group in regard to the following aspects: (1) days necessary for the disappearance of residual urine, (2) appearance of urinary sensation, (3) acquirement of urinary sensation, (4) incidence of urinary incontinence, (5) residual urine/bladder capacity ratio, (6) cystometric findings, and others. Effectiveness of our procedures, particularly of Type IV, may be ascribed to the supported bladder trigone and fundus by sutured tissues and to the acquirement of urinary sensation, rather than to the restoration of nervous contact between the bladder and the micturition center in the spinal cord.

Adnexa Uteri↗
PubMedDate not supplied

In vivo antibacterial activity of a prodrug of NM394, a thiazetoquinoline carboxylic acid derivative.

NM394 (6-fluoro-1-methyl-4-oxo-7-(1-piperazinyl)-4H-[1,3]-thiazeto [3,2-a]quinoline-3-carboxylic acid) has potent, broad-spectrum antibacterial activity in vitro, but not in vivo. To increase the bioavailability of NM394, various prodrugs were synthesized and tested. One of them, NM441, an N-(5-methyl-2-oxo-1,3-dioxol-4-yl) derivative, showed potent in vivo antibacterial activity. Using thin-layer chromatography-bioautography, we confirmed that after oral administration, NM441 was readily absorbed and hydrolyzed to NM394. Other prodrugs of NM394 were only partially metabolized to NM394. In pharmacokinetic studies in mice and monkeys, we found that the blood levels of NM394 were 7.8 and 5.9 times greater, respectively, when NM441 rather than NM394 was administered. These findings suggest that NM441 is an effective prodrug of NM394.

Animals↗