In a study of the very earliest phases of treatment using anti-tuberculosis drugs, researchers found that exponential killing of bacteria was more rapid for the drug isoniazid over the first 2 days; then rifampin became the dominant drug through day 14. The investigators counted colony-forming units of tuberculosis bacteria in sputum from 100 patients at 2-day intervals. The patients, who were previously untreated, were given 22 regimens of isoniazid, rifampin, pyrazinamide, ethambutol, or streptomycin, either alone or in various combinations, for 14 days. According to the authors, it was clear that there were two distinct phases in the early bactericidal activity of anti-tuberculosis drugs. In Phase 1, which lasts about 2 days, exponential killing was more rapid than in Phase 2. In Phase 1, isoniazid had a killing rate that was the largest among the drugs measured. During Phase 2, from the end of day 2 through day 14, the killing rate was slower and the dominant drug was rifampin, whose rate of kill was unaffected by isoniazid. The study was published in the second issue for May 2003 of the American Thoracic Society's peer-reviewed American Journal of Respiratory and Critical Care Medicine.
ACUTE RESPIRATORY FAILURE REVEALS MONOCYTIC LEUKEMIA
In 20 intensive care patients studied by French investigators, the first manifestation of acute monocytic leukemia was severe respiratory distress. According to the authors, in the group of 20 patients admitted to the intensive care unit (ICU) over an 18-year period, there were three remarkable features: rapidly progressive respiratory distress revealing acute leukemia; myeloid leukemia (a malignancy of the blood-forming tissues); and respiratory deterioration after chemotherapy began. The authors believe that a very unique feature of this study involved the fact that the patients' leukemia was diagnosed only after evaluation for acute respiratory failure. Respiratory function deteriorated even further in all patients within a few hours after the initiation of chemotherapy. The researchers pointed out that this factor suggested a need for ICU admission before starting chemotherapy. They said that the onset of acute respiratory failure in patients with acute monocytic leukemia should not be viewed as a terminal event. Rather, the diagnosis should lead to early invasive, diagnostic, and therapeutic management. The survival rate in the 13 men and 7 women (median age 50) in the study was 50 percent. The research appears in the second issue for May 2003 of the American Journal of Respiratory and Critical Care Medicine.
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Journal
American Journal of Respiratory and Critical Care Medicine