Browsing by Author "10176705 - Pretorius, Petrus Jacobus"
Now showing items 1-20 of 37
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8-Oxo-7,8-dihydro-2’-deoxyguanosine, reactive oxygen species and ambulatory blood pressure in African and Caucasian men: the SABPA study
Mels, C.M.C.; Schutte, A.E.; Schutte, R.; Pretorius, P.J.; Smith, W.; Huisman, H.W.; Van der Westhuizen, F.H.; Fourie, C.M.T.; Van Rooyen, J.M.; Kruger, R.; Louw, R.; Malan, N.T.; Malan, L. (Taylor & Francis, 2014)Various studies indicate a relationship between increased oxidative stress and hypertension, resulting in increased DNA damage and consequent excretion of 8-oxo-7,8-dihydro-2’-deoxyguanosine (8-oxodG). The aim of this study ... -
Adjustments to the preanalytical phase of quantitative cell-free DNA analysis
Bronkhorst, Abel Jacobus; Aucamp, Janine; Pretorius, Piet J. (Elsevier, 2016)Evaluating the kinetics of cell-free DNA (cfDNA) in the blood of cancer patients could be a strong auxiliary component to the molecular characterization of cfDNA, but its potential clinical significance is obscured by the ... -
Assessing the DNA methylation status of single cells with the comet assay
Wentzel, Johannes F.; Gouws, Chrisna; Huysamen, Cristal; Van Dyk, Etresia; Koekemoer, Gerhard; Pretorius, Pieter J. (Elsevier, 2010)The comet assay (single cell gel electrophoresis) is a cost-effective, sensitive, and simple technique that is traditionally used for analyzing and quantifying DNA damage in individual cells. The aim of this study was to ... -
Cell-free DNA in a three-dimensional spheroid cell culture model: a preliminary study
Aucamp, Janine; Calitz, Carlemi; Bronkhorst, Abel J.; Hamman, Sias; Gouws, Chrisna; Pretorius, Piet J. (Elsevier, 2017)Background Investigating the biological functions of cell-free DNA (cfDNA) is limited by the interference of vast numbers of putative sources and causes of DNA release into circulation. Utilization of three-dimensional ... -
Cell-free DNA: preanalytical variables
Bronkhorst, Abel Jacobus; Aucamp, Janine; Pretorius, Piet J. (Elsevier, 2015)Since the discovery of cell-free DNA (cfDNA) in human blood, most studies have focused on diagnostic and prognostic uses of these markers for solid tumors. Except for some prenatal tests and BEAMing, cfDNA analysis has not ... -
Characterization of the cell-free DNA released by cultured cancer cells
Bronkhorst, Abel Jacobus; Wentzel, Johannes F.; Aucamp, Janine; Van Dyk, Etresia; Du Plessis, Lissinda; Pretorius, Piet J. (Elsevier, 2016)The most prominent factor that delays the translation of cell-free DNA (cfDNA) analyses to clinical practice is the lack of knowledge regarding its origin and composition. The elucidation of the former is complicated by ... -
Circulating DNA: its origin and fluctuation
Van der Vaart, Maniesh; Pretorius, Piet J. (Wiley, 2008)Circulating DNA is present in the blood of all individuals, but it has been found that cancer patients and patients with a variety of other conditions have increased amounts of these circulating DNA fragments in their ... -
Continuous adaptation through genetic communication: a putative role for cell-free DNA
Peters, Dimetrie L.; Pretorius, Piet J. (Taylor & Francis, 2012)Introduction: The virtosome fraction of cell-free DNA, being newly synthesised, capable of horizontal gene transfer (HGT) and subsequent genomic incorporation and expression, may play crucial roles in the biological functions ... -
The diverse origins of circulating cell‐free DNA in the human body: a critical re‐evaluation of the literature
Aucamp, Janine; Bronkhorst, Abel J.; Pretorius, Piet J.; Badenhorst, Christoffel P.S. (Wiley, 2018)Since the detection of cell‐free DNA (cfDNA) in human plasma in 1948, it has been investigated as a non‐invasive screening tool for many diseases, especially solid tumours and foetal genetic abnormalities. However, to date ... -
DNA damage and repair capacity in hairdressers exposed to chemical products: a pilot study
Eloff, F.C.; Preston, R.; Pretorius, P.J.; Du Plessis, J.L.; Laubscher, P.J.; Van Aarde, M.N.; Van der Westhuizen, F.H.; Franken, A. (SASOM, 2013)Hairdressers are exposed to numerous hazardous chemical substances, some of which are known or suspected allergens, carcinogens or organic solvents. The objectives of this study were to compare DNA damage and DNA repair ... -
DNA damage and repair detected by the comet assay in lymphocytes of African petrol attendants: a pilot study
Keretetse, G.S.; Laubscher, P.J.; Du Plessis, J.L.; Pretorius, P.J.; Van der Westhuizen, F.H.; Van Deventer, E.; Van Dyk, E.; Eloff, F.C.; Van Aarde, M.N.; Du Plessis, L.H. (Oxford Univ Press, 2008)Petrol attendants are exposed to petrol volatile organic compounds (VOCs) which may have genotoxic and carcinogenic effects. The single-cell gel electrophoresis assay (comet assay) is a method highly sensitive to DNA damage ... -
An enquiry concerning the characteristics of cell-free DNA released by cultured cancer cells
Bronkhorst, Abel Jacobus; Wentzel, Johannes F.; Aucamp, Janine; Van Dyk, Etresia; Du Plessis, Lissinda H.; Pretorius, Piet J. (Springer, 2016)Non-invasive screening that utilizes cell-free DNA (cfDNA) offers remarkable potential as a method for the early detection of genetic disorders and a wide variety of cancers. Unfortunately, one of the most prominent elements ... -
Exposure to high levels of fumarate and succinate leads to apoptotic cytotoxicity and altered global DNA methylation profiles in vitro
Wentzel, Johannes F.; Lewies, Angélique; Bronkhorst, Abel J.; Van Dyk, Etresia; Du Plessis, Lissinda H.; Pretorius, Piet J. (Elsevier, 2017)In the Krebs cycle, succinate is oxidized to fumarate by succinate dehydrogenase (SDH), followed by the conversion of fumarate to malate by fumarate hydratase (FH). In cells with defective SDH and FH, the Krebs cycle is ... -
Genetic polymorphisms of beta(2)- and beta(3)- adrenergic receptor genes associated with characteristics of the metabolic syndrome in black South African women
Van Rooyen, J.M.; Pretorius, P.J.; Britz, M.; Huisman, H.W.; Schutte, A.E.; Towers, G.W.; Olckers, A.; Malan, N.T.; Malan, L.; Schutte, R. (Thieme, 2008)Background: Genetic variation in the β2 (ADRB2) and β3 (ADRB3) adrenergic receptor genes are associated with obesity and insulin resistance. To further elucidate the role of these genes in the pathophysiology of obesity ... -
Hereditary tyrosinemia type 1 metabolites impair DNA excision repair pathways
Van Dyk, E.; Steenkamp, A.; Koekemoer, G.; Pretorius, P.J. (Elsevier, 2010)Hereditary tyrosinemia type 1 is an autosomal recessive metabolic disorder, which is caused by a defective fumarylacetoacetate hydrolase enzyme, and consequently metabolites such as succinylacetone and p-hydroxyphenylpyruvate ... -
A historical and evolutionary perspective on circulating nucleic acids and extracellular vesicles: circulating nucleic acids as homeostatic genetic entities
Aucamp, Janine; Bronkhorst, Abel Jacobus; Pretorius, Piet J. (Springer, 2016)The quantitative and qualitative differences of circulating nucleic acids (cirNAs) between healthy and diseased individuals have motivated researchers to utilize these differences in the diagnosis and prognosis of various ... -
A historical and evolutionary perspective on the biological significance of circulating DNA and extracellular vesicles
Aucamp, Janine; Bronkhorst, Abel J.; Badenhorst, Christoffel P.S.; Pretorius, Piet J. (Springer, 2016)The discovery of quantitative and qualitative differences of the circulating DNA (cirDNA) between healthy and diseased individuals inclined researchers to investigate these molecules as potential biomarkers for non-invasive ... -
Impaired DNA repair and genomic stability in hereditary tyrosinemia type 1
Van Dyk, E.; Pretorius, P.J. (Elsevier, 2012)The autosomal recessive disorder, hereditary tyrosinemia type 1 (HT1), is caused by a defective fumarylacetoacetate hydrolase enzyme. Consequently intermediate metabolites such as fumarylacetoacetate, succinylacetone and ... -
In vitro antioxidant, antimutagenic and genoprotective activity of Rosa roxburghii fruit extract
Van der Westhuizen, Francois H.; Janse van Rensburg, Catharina S.; Rautenbach, George S.; Loots, Du Toit; Huysamen, Cristal; Louw, Roan; Pretorius, Pieter J.; Erasmus, Elardus; Marnewick, Jeanine L. (Wiley, 2008)The antioxidant properties of the fruit of the Rosa roxburghii (RR) plant have been associated with several putative health promoting effects. The possible cytotoxic, mutagenic/antimutagenic and genotoxic effects of RR ... -
Investigating the effects of the presence of foreign DNA on DNA methylation and DNA repair events in cultured eukaryotic cells
Du Toit, J.; Van der Westhuizen, F.H.; Pretorius, P.J. (Elsevier, 2013)Methylation of DNA in eukaryotic cells, global as well as gene-specific, is affected by endogenous and endogenous factors. In this paper, it is reported that deviations in DNA methylation and expression of genes involved ...