THE OSTIA VENAE HEPATICAE AND THE RETHROHEPATIC ...

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Characterization of mutations of the PKD1 gene has been limited by the fact that three - fourths of this
gene at its 5’ end is homologous to sequences of at least three other genes on the same chromosome. We
have therefore developed a method of long reverse transcription PCR for selective amplification of the
entire coding sequence of the PKD1 gene from its mRNA. A PCR primer specific to the sequence in the
3’ unique region of the PKD1 gene was synthesized for use coupled with a primer binding to sequence in
the homologous region at a distance of about 13.6 kb apart. The commercial availability of RNase Hfree
reverse transcriptase for long cDNA synthesis and of an enzyme mixture containing Taq and Pfu
DNA polymerases for long-range PCR have made this development possible. The long PCR product
was proven to be derived from PKD1-mRNA. The results clearly indicated that the long PCR product
contained the coding sequence derived from PKD1-mRNA. To our knowledge, this is the first report of
a pricedure that can reproducibly isolate full-length PKD1 coding sequence from its mRNA transcript,
which will prove useful for screening and characterization of mutations in the PKD1 gene.
(BioTechniques 26:126-132 (January 1999) )
Faculty of Medicine Siriraj Hospital
MONITORING AREA UNDER THE CURVE OF CYCLOSPORINE BY
LIMITED SAMPLING STRATEGY
(298)
Dejvorakul S., Vasuvattakul S., Mareesangthip K., Leowattana W., Sritippayawan S., Ong-ajjooth
L., Nimmannit S.
Renal Unit, Department of Medicine, Department of Clincal Pathology, Siriraj Hospital,
Bangkok, Thailand.
Backgroud : Cyclosporine A is considered as the principal immunosuppressive drug in
organ transplantation. Careful drug monitoring is necessary due to its narrow therapeutic range. Area
under the time-concentration curve (AUC) has been shown to represent drug exposure more accurately
than trough level. However, it is impractical because multiple blood samples are required. Currently
Neoral a new form of cyclosporine is wildly used in clinical practice. Since its microemulsion composition
give a highly reproducible pharmacokinetic profiles, we expected that fewer blood samples could be
required in monitoring the blood level. This study was carried out to investigate the accuracy of limited
sampling strategy in monitoring the cyclosporine level.
Methods : Blood for cyclosporine assay (cloned enzyme donor immunoassay) was
obtained at 0, 0.5,1,1,5,2,3,4,6,8,10 and 12 hr after neoral administration in 40 renal transplant patients.
Multiple stepwise regression analysis was used to identify timepoints of blood samples. which showed
good correlation with AUC. Prediction errors of the blood sampling strategies were compared to select
the best one.
Results : The study showed that at least three time-points of blood collection were
required to predict AUC accurately. [more than 90% of the estimated AUC were within the acceptable
range of actual AUC (10% error)]. The best three time-points that predict AUC of cyclosporine were at
1-3-10 hr after drug administration (r=0.99, p