To evaluate the clinical application of the detection of the drug resistant genes rPOB, katG, rPSL, PncA and embB in M. tuberculosis by using polymerase chain reaction-single strand conformation ...polymorphism (PCR-SSCP) analysis.
Gene mutations and anti-tuberculous drug susceptibility test were analyzed in 109 M. tuberculosis isolates by PCR-SSCP and the proportion method on Lowenstein-Jensen medium, respectively. The therapeutic effect was evaluated in patients with tuberculosis.
Isolates from more than 50% of the patients with pulmonary tuberculosis were resistant to at least two drugs. The total rates of drug resistance to rifampin (RFP), isoniazid (INH), streptomycin (SM), pyrizinamide (PZA) and ethambutol (EB) were 80.7%, 71.5%, 78.8%, 57.7%, and 48.6%, respectively. The gene mutation rates of rpoB, katG, rpsL, pncA and embB were 76%, 68%, 71%, 51% and 30%, respectively. The gene mutations were correlated with the degree of drug-resistance to M. tuberculosis. Most of the gene mutations were found in drug-
We compare four open-loop transmit diversity schemes in a coded Orthogonal Frequency Division Multiplexing (OFDM) system with four transmit antennas, namely cyclic delay diversity (CDD), Space-Time ...Block Code (STBC, Alamouti code is used) with CDD, Quasi-Orthogonal STBC (QO-STBC) and Minimum-Decoding-Complexity QOSTBC (MDC-QOSTBC). We show that in a coded system with low code rate, a scheme with spatial transmit diversity of second order can achieve similar performance to that with spatial transmit diversity of fourth order due to the additional diversity provided by the phase shift diversity with channel coding. In addition, we also compare the decoding complexity and other features of the above four mentioned schemes, such as the requirement for the training signals, hybrid automatic retransmission request (HARQ), etc. The discussions in this paper can be readily applied to future wireless communication systems, such as mobile systems beyond 3G, IEEE 802.11 wireless LAN, or IEEE 802.16 WiMAX, that employ more than two transmit antennas and OFDM.
