TY  - JOUR
A1  - Putra, Sulistyo Emantoko Dwi
A1  - Neuber, Corinna
A1  - Reichetzeder, Christoph
A1  - Hocher, Berthold
A1  - Kleuser, Burkhard
T1  - Analysis of genomic DNA methylation levels in human placenta using liquid Chromatography-Electrospray ionization tandem mass spectrometry
JF  - Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry and pharmacology
N2  - Background: DNA-methylation is a common epigenetic tool which plays a crucial role in gene regulation and is essential for cell differentiation and embryonic development. The placenta is an important organ where gene activity can be regulated by epigenetic DNA modifications, including DNA methylation. This is of interest as, the placenta is the interface between the fetus and its environment, the mother. Exposure to environmental toxins and nutrition during pregnancy may alter DNA methylation of the placenta and subsequently placental function and as a result the phenotype of the offspring. The aim of this study was to develop a reliable method to quantify DNA methylation in large clinical studies. This will be a tool to analyze the degree of DNA methylation in the human placenta in relationship to clinical readouts. Methods: Liquid chromatography-electrospray ionization/multi-stage mass spectrometry (LC-ESI/MS/MS) technique was used for the quantification of the 5dmC/dG ratio in placentas from 248 healthy pregnancies. We were able to demonstrate that this method is a reliable and stable way to determine global placental DNA methylation in large clinical trials. Results/Conclusion: The degree of placental DNA methylation seen in our pilot study varies substantially from 2% to 5%. The clinical implications of this variation need to be demonstrated in adequately powered large studies.
KW  - Pregnancy
KW  - Placenta
KW  - Methylation
KW  - Global
KW  - LC-MS/MS
KW  - Fetal programming
KW  - Clinical
Y1  - 2014
U6  - https://doi.org/10.1159/000358666
SN  - 1015-8987
SN  - 1421-9778
VL  - 33
IS  - 4
SP  - 945
EP  - 952
PB  - Karger
CY  - Basel
ER  - 
TY  - JOUR
A1  - Putra, Sulistyo Emantoko Dwi
A1  - Tsuprykov, Oleg
A1  - Von Websky, Karoline
A1  - Ritter, Teresa
A1  - Reichetzeder, Christoph
A1  - Hocher, Berthold
T1  - Dealing with large sample sizes: comparison of a new one spot dot blot method to western blot
JF  - Clinical laboratory : the peer reviewed journal for clinical laboratories and laboratories related to blood transfusion
N2  - Background: Western blot is the gold standard method to determine individual protein expression levels. However, western blot is technically difficult to perform in large sample sizes because it is a time consuming and labor intensive process. Dot blot is often used instead when dealing with large sample sizes, but the main disadvantage of the existing dot blot techniques, is the absence of signal normalization to a housekeeping protein.
 Methods: In this study we established a one dot two development signals (ODTDS) dot blot method employing two different signal development systems. The first signal from the protein of interest was detected by horseradish peroxidase (HRP). The second signal, detecting the housekeeping protein, was obtained by using alkaline phosphatase (AP).
 Results: Inter-assay results variations within ODTDS dot blot and western blot and intra-assay variations between both methods were low (1.04 - 5.71%) as assessed by coefficient of variation.
 Conclusions: ODTDS dot blot technique can be used instead of western blot when dealing with large sample sizes without a reduction in results accuracy.
KW  - one dot two development signals (ODTDS) dot blot
KW  - western blot
KW  - protein quantification
KW  - large sample size studies
KW  - comparison
Y1  - 2014
U6  - https://doi.org/10.7754/Clin.Lab.2014.140317
SN  - 1433-6510
VL  - 60
IS  - 11
SP  - 1871
EP  - 1877
PB  - Clin Lab Publ., Verl. Klinisches Labor
CY  - Heidelberg
ER  -