As a model of opportunistic infection, pneumonia was produced by Pseudomonas aeruginosa (P. aeruginosa) in rabbit and bactericidal activity was measured with following results. There was a significant difference in ability to cause pneumonia between P. aeruginosa No.8and P. aeruginosa No.93,108 colony forming unit (du) inoculation produced pneumonia in P. aeruginosa No.93, but not in P. aeruginosa No.8.
In P. aeruginosa No.93, viable cell count in the lung lesion decreased with the time course, which was associated with improvement of pneumonia. When inoculum size was increased to 10 ¹⁰c fu, pneumonia worsened in P. aeruginosa No.93and pneumonia was produced in P. aeruginosa No.8. Bactericidal activity of rabbit's blood for P. aeru ginosa No.8 was strong, but was weak for P. aeruginosa No.93; difference significant.
Administration of betamethasone,10mg/kg X 2 prior to 10 ¹⁰ cfu inoculation of P. aeruginosa No.93, worsened pneumonia and blood culture was positive in all cases. Bacteria in the blood increased with further administration of betamethasone, and all rabbits died. However, blood culture remained negative in 10¹⁰ cfu inoculation of P. aeruginosa No.8 with continuous administration of betamethasone and viable cell count in the lung lesion tended to decrease.
Therefore, administration of betamethasone caused worsening of pneumonia in strains with pneumonia inducibility, whereas effect of betamethasone was mild in strains without pneumonia inducibility. When bactericidal activity was evaluated in vitro, dose dependent decrease was observed at 1 hour and 4 hour incubation against P. aeruginosa No.93, whereas only at' 4 hour in No.8. Fourteen days administration of betamethasone 2mg/kg, bactericidal activity of blood ag ainst P. aeruginosa No.8 increased slightly, but there was no change in No.93. When the dos e was increased 10mg/kg, bactericidal activity slightly decreased on the next day in P. aeruginosa No.93, whereas decreased slightly on the third and seventh day in No.8.
Conclusion: The effect of steroid on inducibility of pneumonia depends on the virulence; worsen the clinical picture of pneumonia against strong virulet strain, but no influence against the weak virulent strain.

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126 adult patients aged 16-85 with previous untreated acute leukemia (AML 98, ALL 28)received induction chemotherapy (behenoyl AraC + DNA + 6MP PSL for AML, ADR + VCR +PSL for ALL) and several consolidation chemotherapies from 1986 to 1992. As a final consolidation,37 patients received high dose Ara-C (HDAC) regimen (2 g /m2 X 2/day X 5).
93 patients (73.8%) achieved a CR (AML 73.5%, ALL 75%). At median follow-up of 36mo., overall survival was 24.1% for AML and 11.5% for ALL. DFS (disease free survival) was 17.3% for AML and 25.3% for ALL. In AML, for patients≤45years of age, DFS was 11.3%, as compared with 21.5% for patients greater the age 45. There was a trend for AML with t(8; 21)and inv16 to have better prognosis. The other prognostic factors were variable in our study. HDAC regimen was not a favorable prognostic factor for survival.
It is hoped intensive chemotherapy in an early consolidation, especially for AML patients≤45 years. And allogeneic BMT will be required deliberately and positively from now for acute leukemia.

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