The developmentally regulated expression of forms of cytochrome P-450, namely, those encoded by lambda HFL33 and NF25 or HLp cDNAs, which were isolated from respective fetal and adult human liver cDNA libraries, was investigated. When EcoRI fragments of cDNA clones of lambda HFL33 and NF25 were used as probes, these probes hybridized with RNA from both fetal and adult human livers. However, when oligonucleotides specific to the coding and 3'-noncoding region of lambda HFL33 (oli-HFL and oli-HFL3', respectively) were used as probes, these probes gave hybridizable bands with RNA from fetal but not adult livers. On the other hand, an oligonucleotide probe specific to the coding region of NF25 and HLp (oli-NF) gave positive bands with RNA only from adult livers. These results indicate that P-450(HFL33) is expressed specifically in fetal livers and that neither P-450NF nor HLp is expressed in fetal livers, but one or both are expressed in adult livers.

From a human fetal liver cDNA library, a cDNA clone (lambda HFL33) containing the entire coding region for a form of cytochrome P-450 related to P-450 HFLa was obtained. The clone was 1,971 bp long and had an open reading frame of 1,509 nucleotides coding for a 503 amino acid polypeptide. The nucleotide and the deduced amino acid sequences of lambda HFL33 were very similar to but clearly distinct from those of NF25 and HLp cDNAs, which code for forms of cytochrome P-450 in adult human liver. The deduced N-terminal amino acid sequence of the HFL33 protein was identical to that of P-450 HFLa.

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An OFDM technique has been utilized for wireless local area networks (WLANs). Spatial division multiplexing using a multiple-input multiple-output (MIMO) technique has been studied to increase the transmission rate over 100 Mbps. Before we detect transmitted data, we need AGC adjustment, timing synchronization, frequency offset estimation, and channel estimation using a preamble. The current WLAN system with a single transmit antenna based on the IEEE 802.11a standard uses the four OFDM symbol duration preamble. However, the preamble period proposed so far for the MIMO-OFDM system grows linearly with the transmit antenna number. This results in an increased overhead, and the conventional technique is not efficient. In this paper, we present the channel and frequency offset estimation scheme using a preamble with four OFDM symbol duration for the MIMO-OFDM system in WLANs. This preamble has the same duration as that of the IEEE 802.11a standard, and does not increase the overhead. Computer simulation results are provided to demonstrate the performance of the proposed scheme. 0-7803-8521-7/04/$20.00 (C) 2004 IEEE 1523 0-7803-8521-7/04/$20.00 © 2004 IEEE * m,1 (t) and x m,2 (t)x * m,2 (t). We calculate complex quantities p prc m as follows: p prc m = 63 t=0 x m,1 (t)x * m,1 (t) * x m,2 (t)x * m,2 (t) . (13) 0-7803-8521-7