Circulating Fetal RNA in Maternal Plasma POON, LEO L. M.; LEUNG, TSE N.; LAU, TZE K. ...
Annals of the New York Academy of Sciences,
September 2001, Letnik:
945, Številka:
1
Journal Article
Recenzirano
: The discovery of cell‐free nucleic acids in plasma has opened up new possibilities for noninvasive clinical diagnosis. We demonstrate the presence of cell‐free fetal RNA in maternal plasma, ...indicating that plasma fetal RNA might be used as a marker for noninvasive prenatal diagnosis.
Severe acute respiratory syndrome (SARS) Ngan Kee, Warwick D; Leung, Tse N
International journal of obstetric anesthesia,
07/2003, Letnik:
12, Številka:
3
Journal Article
We investigated antibacterial activity of ZnO nanorods prepared by a hydrothermal method against a gram-negative bacterium
Escherichia coli and a gram-positive bacterium
Bacillus atrophaeus. ...Antibacterial activity of ZnO nanorod coatings was studied on solid substrates covered with nutrient agar, as well as in liquid nutrient broth for different concentrations of ZnO nanorods, nanoparticles, and powder. ZnO exhibited antibacterial activity against both
E. coli and
B. atrophaeus, but it was considerably more effective in the latter case (at 15 mM vs. 5 mM concentration, respectively, showing zero viable cell count). For both organisms, damage of the cell membranes was found, and the effect was more pronounced for
B. atrophaeus. Chemiluminescence analysis has been used to detect the release of hydrogen peroxide from ZnO structures, and the effect of H
2O
2 on the
E. coli and
B. atrophaeus was studied. Since significant differences were observed in the effect of ZnO nanostructures and H
2O
2 on
B. atrophaeus, it can be concluded that there are other mechanisms contributing to the antibacterial activity of ZnO nanostructures.
Background: We recently demonstrated that the promoter of the RASSF1A gene is hypermethylated in the placenta and hypomethylated in maternal blood cells. This methylation pattern allows the use of ...methylation-sensitive restriction enzyme digestion for detecting the placental-derived hypermethylated RASSF1A sequences in maternal plasma. Methods: We performed real-time PCR after methylation-sensitive restriction enzyme digestion to detect placental-derived RASSF1A sequences in the plasma of 28 1st-trimester and 43 3rd-trimester pregnant women. We used maternal plasma to perform prenatal fetal rhesus D (RhD) blood group typing for 54 early-gestation RhD-negative women, with hypermethylated RASSF1A as the positive control for fetal DNA detection. Results: Hypermethylated RASSF1A sequences were detectable in the plasma of all 71 pregnant women. The genotype of plasma RASSF1A after enzyme digestion was identical to the fetal genotype in each case, thus confirming its fetal origin. Nineteen of the 54 pregnant women undergoing prenatal fetal RhD genotyping showed undetectable RHD sequences in their plasma DNA samples. The fetal DNA control, RASSF1A, was not detectable in 4 of the 19 women. Subsequent chorionic villus sample analysis revealed that 2 of these 4 women with negative RHD and RASSF1A signals were in fact carrying RhD-positive fetuses. Conclusions: Hypermethylated RASSF1A is a universal marker for fetal DNA and is readily detectable in maternal plasma. When applied to prenatal RhD genotyping, this marker allows the detection of false-negative results caused by low fetal DNA concentrations in maternal plasma. This new marker can also be applied to many other prenatal diagnostic and monitoring scenarios.
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