In vitro and in vivo efficacies of T-3811ME (BMS-284756) against Mycoplasma pneumoniae.

T-3811, the free base of T-3811ME (BMS-284756), a new des-F(6)-quinolone, showed a potent in vitro activity (MIC at which 90% of the isolates tested are inhibited [MIC(90)], 0.0313 microg/ml) against Mycoplasma pneumoniae. The MIC(90) of T-3811 was 4-fold higher than that of clarithromycin but was 4- to 8-fold lower than those of trovafloxacin, gatifloxacin, gemifloxacin, and moxifloxacin and was 16- to 32-fold lower than those of levofloxacin, ciprofloxacin, and minocycline. In an experimental M. pneumoniae pneumonia model in hamsters, after the administration of T-3811ME (20 mg/kg of body weight as T-3811, once daily, orally) for 5 days, the reduction of viable cells of M. pneumoniae in bronchoalveolar lavage fluid was greater than those of trovafloxacin, levofloxacin, and clarithromycin (20 and 40 mg/kg, orally) (P < 0.05).

[Nephrotoxicity of piperacillin combined with furosemide in rats].

Nephrotoxicity of piperacillin (PIPC) was evaluated in rats after combined administration with furosemide. After intravenous administration of PIPC (1600 mg/kg), the rats showed no change in urinalysis, biochemical analysis of plasma and histopathological analysis. The rats receiving furosemide (100 mg/kg) showed elevation of urinary NAG, BUN and creatinine concentrations, and showed slight degeneration of the renal proximal tubules. The rats receiving PIPC (1600 mg/kg) and furosemide (100 mg/kg) showed elevation of BUN and creatinine concentrations, and showed slight degeneration of the proximal tubules. These changes were comparable to those in rats receiving furosemide alone. The rats receiving cephaloridine (1600 mg/kg) showed elevation of urinary protein, BUN and creatinine concentrations, and showed moderate degeneration and necrosis of the proximal tubules. The nephrotoxicity was enhanced by combination with furosemide. In conclusion, no enhanced effect of nephrotoxicity was observed by combination of PIPC with furosemide.

A new model of pulmonary superinfection with Aspergillus fumigatus and Pseudomonas aeruginosa in mice.

We have produced a new model of pulmonary super-infection with Aspergillus fumigatus and Pseudomonas aeruginosa in immunosuppressed mice. Male ICR mice were given an intratracheal inoculation of 4 x 10(5) conidia of A. fumigatus in agar beads, and were immunosuppressed with 100 mg/kg subcutaneous injections of cortisone acetate on days 7, 9, 12, 14, and 16 after inoculation. Twelve days after inoculation, with the agar beads, the mice were challenged with the intranasal instillation of 2 x 10(6) CFU of P. aeruginosa. The survival rates of superinfected, A. fumigatus-alone, P. aeruginosa-alone, and non-infected mice were 50%, 30%, 90%, and 100% 14 days after pseudomonal infection (26 days after inoculation of A. fumigatus), respectively. In the superinfected mice, both A. fumigatus and P. aeruginosa were detected more than 10 days after pseudomonal infection (22 days after inoculation of A. fumigatus). Histopathological examination revealed peribronchial necrosis around A. fumigatus hyphae and inflammation by P. aeruginosa. This infection model in mice would be useful for studying the pathogenesis of superinfection.

Application of a centrifugal shooting type polishing system to polish pure titanium.

Titanium is a difficult metal to grind, and thus mechanical polishing using conventional rotating tools takes a lot of time. The purpose of this study was to examine the polishing effect of a centrifugal shooting type polishing system on a pure titanium surface processed with a CAD/CAM system. The specimens' surfaces were polished for various times using this apparatus, then the center line average roughness (Ra) of each specimen was measured with surface roughness measuring apparatus. In addition, the surfaces after polishing were observed with a scanning electron microscope. After 50 sec of polishing, Ra decreased from 1.1 microns to less than 0.6 micron, and after 60 sec of polishing the cutting marks generated by the CAD/CAM system disappeared and a smooth surface was observed. Therefore, it appears that a centrifugal shooting type polishing system is effective at polishing pure titanium.

Labor reduction for mold preparation of a commercial titanium cast denture system using a heat-shock method.

The purpose of this study was to investigate the application of a heat-shock method to fabricate titanium cast plates. Duplications of a maxillary model were prepared using DM under different firing schedules. Molds with patterns on the duplications were made by an outer investment (D), followed by heat shock at 850 degrees C. Duplications heat shocked at 850 degrees C after 30 min from mixing exploded within a few minutes. This explosion was successfully avoided by a drying procedure prior to the heat-shock. The molds were available for the heat shock at 850 degrees C when the duplicate models were prepared by firing either using the conventional method and the heat shock above method described. Therefore, we could reduce the preparation time from about 16 hr with the conventional method to about 10 hr at the longest with the heat-shock method. These results suggested that the heat-shock method was labor-saving for fabricating titanium cast denture plates when controlling preliminary conditions prior to use.

[Antibacterial activity of tosufloxacin against fresh clinical isolates].

The antibacterial activity of tosufloxacin (TFLX) was compared with those of other new quinolones (ofloxacin, ciprofloxacin, sparfloxacin and fleroxacin) against clinical isolates. These isolates had been collected from May to June 1993 (22 species, 260 strains) and from June to July 1992 (Staphylococcus aureus and Pseudomonas aeruginosa, 87 strains) in Toyama municipal hospital. TFLX showed the most potent activities against methicillin-susceptible S. aureus, methicillin-susceptible Staphylococcus epidermidis, methicillin-resistant S. epidermidis, Enterococcus faecalis and Escherichia coli in 1993, at MIC50 levels. The MIC50's of TFLX for these species ranged from 0.025 to 0.39 microgram/ml. TFLX showed potent activities against Klebsiella pneumoniae and P. aeruginosa, and the MIC50's of TFLX were 0.05 and 0.39 microgram/ml, respectively. However, new quinolone resistant strains (MIC > or = 6.25 micrograms/ml) were found among some species. Especially, the number of methicillin-resistant S. aureus (MRSA) strains resistant to new quinolone exceeded 60% of all the S. aureus isolates in 1993. More MRSA strains resistant to new quinolones were isolated in 1993 than in 1992, and similar result was observed for P. aeruginosa. The coagulase typing was done, and all MRSA strains of resistant to new quinolones produced coagulase type II.