Schisandra chinensis (S. chinensis) contains several compounds that exhibit various physiological activities such as anti-oxidation and anti-inflammation. The major compounds of S. chinensis are lignans such as schisandrol A, schisandrol B, schisandrin A, gomisin N and schisandrin C. In this study, the contents of five lignans from S. chinensis was quantitatively analyzed by using high-performance liquid chromatography (HPLC) to find the optimal extraction method. Additionally, the analysis method was validated and a simultaneous analysis method was established. DPPH and ABTS scavenging assays were performed to evaluate the anti-oxidant effect of S. chinensis extracts and fractions. The results showed that the calibration curves of five lignans exhibited high linearity with a correlation coefficient (R²) of 0.9998. The optimal extraction method for S. chinensis was the reflux extraction method with 60% ethanol at 100℃ and the contents of five lignans were 1.73, 0.28, 0.85, 1.28 and 0.41%. The contents of five lignans in n-hexane fraction was 6.1 to 8.5 times compared with those in the extract prepared by optimal extraction method. The results of anti-oxidation of S. chinensis extracts and fractions showed that the anti-oxidant effect was increased dose-dependently depending on the contents of five lignans. Therefore, these results could be used as basic data for the standardization of anti-oxidant health functional foods, cosmetics and medicines including five lignans, which are the active compounds of S. chinensis.
This study was performed in order to evaluate the association of tumour necrosis factor-alpha (TNF-alpha) and transforming growth factor-beta1 (TGF-beta1) gene polymorphisms with renal allograft rejection in Koreans. Five TNF-alpha (-1031T/C, -863C/A, -857C/T, -308G/A and -238G/A) and two TGF-beta1 (codon 10 T/C and codon 25 G/C) single-nucleotide polymorphism (SNP) sites were studied by using polymerase chain reaction (PCR) single-strand conformation polymorphism and PCR restriction fragment length polymorphism methods in 100 controls and 164 patients. The patients underwent renal transplantation, having one or more Human leukocyte antigen (HLA)-A, HLA-B and HLA-DR antigens mismatched with their donors. For the TGF-beta1 gene, we also studied the polymorphism of donors. The allele frequencies of each SNP site in controls were not different from those of patients. The frequency of TNF-alpha high-producer genotype, -308GA, and TGF-beta1 lower (intermediate)-producer genotype, codon 10 CC and codon 25 GG, were significantly higher in patients with recurrent acute rejection episodes (REs), compared to those in patients with no or one RE. The highest risk group for developing recurrent REs showed the combination of TNF-alpha high- and TGF-beta1 lower-producer genotypes. Analysis of chronic renal allograft dysfunction (CRAD) revealed that TGF-beta1 high-producer genotype of donors, codon 10 TT/TC and codon 25 GG, is associated with CRAD especially in patients with recurrent REs. The highest risk group for developing CRAD showed the combination of recipient's TNF-alpha high- and donor's TGF-beta1 high-producer genotypes. These results would be useful for predicting high-risk group for acute rejection or CRAD in renal transplantation.
The frequencies of HLA‐A, ‐B, and ‐DRB1 alleles and A‐B‐DRB1 haplotypes were studied in 510 healthy unrelated Koreans, using serological (for A, B) and polymerase chain reaction (PCR)‐single strand conformation polymorphism (for DRB1) methods. A total of 35 DRB1 alleles were detected and the most frequent alleles were DRB1*1302 (10.9%), *0901 (9.5%), *1501 (8.2%), *0803 (7.3%), *0405 (7.3%), *0101 (6.4%), *0406 (6.0%), and *0701 (6.0%). HLA‐DR4 and DR14 groups were most polymorphic, each group composed of eight DRB1 alleles. Two‐locus associations between HLA‐DRB1 and ‐B loci were analyzed. There were 16 A‐B‐DRB1 haplotypes occurring at frequencies of ≥1%, and the five most common haplotypes were A33‐B44‐DRB1*1302 (5.4%), A33‐B58‐DRB1*1302 (3.7%), A33‐B44‐DRB1*0701 (2.9%), A24‐B7‐DRB1*0101 (2.2%), and A24‐B52‐DRB1*1502 (2.0%). Comparison of the distribution of A‐B‐DRB1 haplotypes among East Asian populations revealed that Koreans are closest to Japanese, but show a higher degree of polymorphism compared with Japanese.
Abstract: Stress‐inducible MICA (MHC class I chain‐related A) is known to bind to NKG2D, which is one of the natural killer (NK) cell receptors, and plays a role in immune surveillance. We have reported that a MICA‐MICB null haplotype is in linkage disequilibrium with HLA‐B*4801 in the Japanese population. In the haplotype, an approximately 100‐kb deletion, including the entire MICA gene, was observed and MICB possessed a premature stop codon. In this study, a multiplex polymerase chain reaction (PCR) method was developed for detecting the MICA deletion. MICB alleles were typed by PCR‐single‐strand conformation polymorphism (SSCP) method and direct sequencing. The frequency of the MICA‐MICB null haplotype was 3.7% on the average, and was strongly associated with HLA‐B48 in seven East Asian populations. It was presumed that the stop codon of MICB gene generated after the large‐scale deletion. The wide distribution of the null haplotype at polymorphic frequencies suggests that the haplotype has been conservatively maintained because of some selective advantage.
A description is given of the tuning method for the boiler air draft control system of coal-fired thermal power plants, especially the speed control of the forced draft fan which supplies air to the boiler. The system transfer function is modeled as first-order system with time delay. The proportional-integral (PI) gains are determined by the Ziegler-Nichols tuning method based on open-loop frequency diagram which is developed from the pulse test data under the various operating conditions. Tuning the gains with this method resulted in successful results, and the validity of design procedure is confirmed through simulations and experiment.< >
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