Fast and accurate method for quantitating E. coli host-cell DNA contamination in plasmid DNA preparations.

Plasmid DNA is being used successfully as a gene delivery vector in a variety of clinical applications. Similar to other pharmaceutical products for clinical use, the plasmid vectors must meet rigorous purity standards. One important contaminant is the DNA of the host cell used to produce the plasmids. We have developed a new method to accurately quantitate E. coli host-cell DNA in plasmid preparations. This method is based on kinetic PCR using the ABI PRISM 7700 with 23S rDNA as a target. This precise assay is significantly faster and has a lower limit of quantitation than the currently used Southern-based methods.

Improved results of an intensified therapy in adult acute lymphocytic leukemia.

Two consecutive studies for adult patients with acute lymphoblastic leukemia without previous treatment were analyzed and compared. Protocol ALL-79 included 137 patients treated with a 'standard therapy' consisting of prednisone, vincristine and daunomycin as induction, CNS prophylaxis with IT chemotherapy and maintenance with 6-mercaptopurine, methotrexate and pulses with vincristine and prednisone. Protocol ALL-82 included 145 patients treated with an 'intensive therapy' consisting of 8 weeks of induction with vincristine, prednisone, daunomycin and L-asparaginase, followed by 6-mercaptopurine, cyclophosphamide and cytosine arabinoside. At 3 months after induction, a 6-week consolidation therapy was given, with vincristine, adriamycin, dexamethasone and L-asparaginase, followed by cyclophosphamide, cytosine arabinoside and 6-mercaptopurine. Rates of complete remission were 80% and 78% for protocols ALL-79 and ALL-82 respectively. The probability of remaining in complete remission at 80 months was 20% and 34%, respectively (p = 0.0014). Median survival for protocol ALL-79 was 14 months, and 34 months for protocol ALL-82; at 80 months the probability of survival is 22% and 35% for the two protocols (P = 0.0024). In protocol ALL-82, the probability of remaining in CR for favorable prognosis patients (age = less than 35 years and WBC = less than 50.000) is 56% at 80 months, and only 8% at 50 months for the unfavorable group (age greater than 35 and/or WBC greater than 50.000) (P = 0.0012). The probability of survival was statistically superior in patients with favorable prognoses, with 54% of them still alive at 60 months compared to only 13% of patients with unfavorable prognoses (P = 0.0085).(ABSTRACT TRUNCATED AT 250 WORDS)