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- Bjohle, J, et al.
(författare)
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Serum thymidine kinase activity compared with CA 15-3 in locally advanced and metastatic breast cancer within a randomized trial
- 2013
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Ingår i: Breast Cancer Research and Treatment. - : Springer Verlag (Germany). - 0167-6806 .- 1573-7217. ; 139:3, s. 751-758
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Tidskriftsartikel (refereegranskat)abstract
- The primary objective was to estimate serum thymidine kinase 1 (TK1) activity, reflecting total body cell proliferation rate including cancer cell proliferation, in women with loco regional inoperable or metastatic breast cancer participating in a prospective and randomized study. Secondary objectives were to analyze TK1 in relation to progression-free survival (PFS), overall survival (OS), therapy response and other tumour characteristics, including CA 15-3, widely used as a standard serum marker for disease progression. TK1 and CA 15-3 were analysed in 198 serum samples collected prospectively from women included in the randomized TEX trial between December 2002 and June 2007. TK1 activity was determined by the ELISA based DiviTum (TM) assay, and CA 15-3 analyses was generated with the electrochemiluminescence immunoassay Cobas Elecsys CA 15-3 II. High pre-treatment TK1 activity predicted shorter PFS (10 vs. 15 months p = 0.02) and OS (21 vs. 38 months, p andlt; 0.0001), respectively. After adjustment for age, metastatic site and study treatment TK1 showed a trend as predictor of PFS (p = 0.059) and was an independent prognostic factor for OS, (HR 1.81, 95 % confidence interval (CI) 1.26-2.61, p = 0.001). There was a trend of shortened OS for women with high CA 15-3 (p = 0.054) in univariate analysis, but not after adjustment for the above mentioned covariates. Both TK1 (p = 0.0011) and CA 15-3 (p = 0.0004) predicted response to treatment. There were statistically different distributions of TK1 and CA 15-3 in relation to the site of metastases. TK1 activity measured by DiviTum (TM) predicted therapy response, PFS and OS in loco regional inoperable or disseminated breast cancer. These results suggest that this factor is a useful serum marker. In the present material, a prognostic value of CA 15-3 could not be proven.
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| 4. |
- Neumüller, Magnus, et al.
(författare)
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HIV reverse transcriptase inhibiting antibodies detected by a new technique : relation to p24 and gp41 antibodies, HIV antigenemia and clinical variables.
- 1991
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Ingår i: Journal of Medical Virology. - : Wiley. - 0146-6615 .- 1096-9071. ; 34:1, s. 55-63
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Tidskriftsartikel (refereegranskat)abstract
- A new assay for HIV reverse transcriptase activity inhibiting antibodies (RTI-ab) was used for the analysis of a large collection of sera sampled before and after confirmation of HIV infection. In this assay HIV-RT was preincubated with diluted serum, after which residual RT activity was determined by a technique using a template coupled to macrobeads and 125I-lodo-deoxyuridine-triphosphate as the tracer-substrate. Of the 936 sera analysed, 818 were found positive for RTI-ab, and 824 were positive in Western blot (Wb). The prevalence of RTI-ab compared to Wb was therefore 99.3%. The corresponding figure for 930 sera analysed for envelope-ab, i.e., gp41-ab, was 823 positive, and of these 930 sera 815 were Wb positive, giving a comparative prevalence of 101%. In contrast, only 678 samples of 993 analyzed for core ab, i.e., p24, were positive, giving a prevalence of 77.0% as 880 of these samples were Wb positive. Thus, RTI-ab was as prevalent as gp41-ab, and although the analyses of RTI-ab amounts in different stages showed decreasing levels in stage IV compared to stages II or III, all of the sera except 1 were found positive in stages III and IV. Further, it was found that both the few RTI-ab negative samples in stage II and the few RTI-ab positive samples among Wb negative sera were sampled in connection with seroconversion. The specificity of the RTI-ab assay was 100% in a test of 200 serum samples from HIV negative blood donors. It was concluded that RTI-ab analyses can be made highly sensitive and specific and useful for studies of HIV infection.
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| 5. |
- Shao, X-W, et al.
(författare)
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Application of a colorimetric chain-termination assay for characterization of reverse transcriptase from 3-azido-2,3-deoxythymidine-resistant HIV isolates
- 2002
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Ingår i: Biotechnology and applied biochemistry. - 0885-4513 .- 1470-8744. ; 35, s. 155-164
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Tidskriftsartikel (refereegranskat)abstract
- wo different enzyme assays, both based on the interaction of native reverse transcriptase(IRT) and 3'-azido-2',3'-deoxythymidine triphosphate (AZT-TP), were used to characterize the enzymesfrom 18 HIV-I isolates with decreased sensitivity to AZT in cell culture. The first assay, which measures the balance between incorporation and excision of AZT monophosphate in the presence of dNTP substrate (in terms of IC50), gave an approx. 9-fold variation in sensitivity to AZT-TP. There was a correlation between the IC50 values and the sensitivity of the corresponding virus to AZT in cell culture (r = 0.60, P < 0.01). The second assay, which was designed specifically for measurement of chain termination in the absence of dNTP substrate (as the concentration of AZT-TP giving 50% residual primer function, or CT50), revealed a more than 600-fold difference between the different isolate RTs. For the majority ofenzymes there was a strict correlation between the results from the two assays; however, four isolatesexhibited significantly higher CT50/IC50 ratios than the other isolates. These differences were not related to sensitivity of the corresponding viruses to AZT but to the occurrence of certain mutations in their pol gene. The four deviating isolates contained either a minimum of four AZT-specific substitutions, including Thr-215 --> Tyr (isolates 134 and 143), or some of the known specific substitutions combined with Thr-39 --> Ala (isolates 80 and 157). The Thr-39 Ala substitution has previously been recorded in connection with AZT/Foscarnet combination therapy.
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| 6. |
- Shao, Xing-Wu, et al.
(författare)
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Use of HIV-1 reverse transcriptase recovered from human plasma for phenotypic drug susceptibility testing
- 2003
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Ingår i: AIDS. ; 17, s. 1463-1471
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To demonstrate the use of HIV-1 reverse transcriplase (RT) recovered directly fromplasma for phenotypic drug susceptibility testing. Methods: Plasma from HIV-1 infected individuals with and without drug resistance-associated mutations were selected for the study. The blind coded plasmas were treated to inactivate cellular enzymes. The virions were immobilized on a gel and washed to remove antiretroviral drugs and RT activity blocking antibodies. The immobilized virions were lysed; the viral RTeluted and quantified, all according to the ExaVir Load procedure. The drug sensitivity profiles of each RT were determined using serially diluted drugs and modified Cavidi HS Lenti RT kits. Results: The phenotypic drug sensitivity profiles of the RT and the patterns of drug resistance mutations were highly concordant. Plasma RT from virions devoid of mutations associated with drug resistance had average 50% inhibitory concentrations (IC50) of 1.5 +/- 0.93 muM for nevirapine, 0.21 +/- 0.099 muM forefavirenz, 7.1 +/- 3.2 muM for delavirdine, 0.42 +/- 0.15 muM for azidothymidine triphosphate and 0.059 +/- 0.018 muM for didehydrothymidine triphosphate. The increase in IC50 value for RT with drugresistance associated substitutions was from 3- to more than 65-fold for non-nucleoside inhibitors and between 2- and 30-fold for thymidine analogue drugs. Conclusion: RT derived from virions recovered from the plasma of HIV infected individuals can be used foranalysis of phenotypic drug susceptibility. The methods presented provide rapid alternatives for analysingphenotypic drug susceptibility especially when the therapy is based on non-nucleoside RT inhibitors and thymidine-analogue drugs.
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