Sianette Kwee's research while affiliated with Aarhus University and other places

Publications (34)

Article
Full-text available
This paper describes the effect of weak microwave fields on the amounts of heat-shock proteins in cell cultures at various temperatures. The field was generated by signal simulation of the Global System for Mobile communications (GSM) of 960 Mhz, used in portable phones. Transformed human epithelial amnion (AMA) cells, growing on glass coverslips,...
Article
The number of reports on the effects induced by radiofrequency (RF) electromagnetic fields and microwave (MW) radiation in various cellular systems is still increasing. Until now no satisfactory mechanism has been proposed to explain the biological effects of these fields. One of the current theories is that heat generation by RF/MW is the cause, i...
Chapter
In spite of numerous studies of the biological effects from exposure to weak electromagnetic(EM) fields, the issue of whether continuous exposure to these fields involves health risks, is still a subject for considerable debate. On cellular level effects on cell proliferation, enzyme activities, calcium transport, transcription and chromosome abera...
Article
Due to the use of mobile telephones, there is an increased exposure of the environment to weak radiofrequency (RF) electromagnetic fields, emitted by these devices. This study was undertaken to investigate if the microwave radiation from these fields will have a similar effect on cell proliferation as weak electromagnetic (ELF) fields. The field wa...
Article
A significant increase in cell growth was registered in human epithelial amnion (AMA) cells, when exposed to a sinusoidal 50 Hz, 50 μT electromagnetic field (S. Kwee and P. Raskmark, Bioelectrochem. Bioenerg., 36 (1995) 109). To study the effects of incoherent magnetic fields on the biological changes caused by the electromagnetic fields, varying l...
Article
To study the effect of extremely low frequency (ELF) magnetic fields on cell growth, human cells (AMA cells) and K14 skin fibroblasts cells, growing in monolayer culture, were exposed to a sinusoidal 50 Hz, 80 μT field. Exposure times varied from 15 to 90 min. Changes in cell proliferation rates were then studied during subsequent field-free incuba...
Article
A comparative study of the electroporation of transformed human amnion (AMA) cells and their primary counterpart is presented. The differences in conditions for electroporation, membrane resealing and viability between these two cell types are reported, as well as the effects of the introduction of three different antibodies on cell proliferation a...
Chapter
A technique was developed to introduce monoclonal antibodies into cultured cells by electroporation, while retaining cell viability at the same time (Kwee et al., 1990). This enabled us to study cell growth and DNA synthesis in response to electroporation and the following uptake of specific antibodies.
Article
Cultured cells grown in monolayers were permeabilized by applying low-voltage electric pulses. The permeabilized cells were able to incorporate extracellular nucleotides into their DNA, as well as various monoclonal antibodies as determined by indirect immunofluorescence. Complete reversibility and long term viability were retained. Both applied vo...
Article
Cultured cells grown in monolayers were permeabilized by applying low-voltage electric pulses. The permeabilized cells were able to incorporate extracellular nucleotides into their DNA, as well as various monoclonal antibodies as determined by indirect immunofluorescence. Complete reversibility and long term viability were retained. Both applied vo...
Article
Full-text available
Comprehensive, computerized databases of cellular protein information derived from the analysis of two-dimensional gels, together with recently developed techniques to microsequence proteins offer a new dimension to the study of genome organization and function. In particular, human protein databases provide an ideal framework in which to focus the...
Article
Databases of protein information from human embryonal lung fibroblasts (MRC-5) have been established using computer analyzed two-dimensional gel electrophoresis. One thousand four hundred and eighty-two cellular proteins (1060 with isoelectric focusing and 422 with nonequilibrium pH gradient electrophoresis, in the first dimension) ranging in molec...
Article
Databases of protein information derived from the analysis of two-dimensional gels have been established from transformed human amnion cells (AMA) and peripheral blood mononuclear cells (PBMCs). A total of 1781 [35S]methionine-labeled AMA proteins (1274 IEF, 537 NEPHGE) and a total of 1311 proteins from PBMC (948 IEF, 363 NEPHGE) were resolved and...
Chapter
The process of the reduction of oxygen to water in the mitochondria has been widely studied in the course of time. It is generally accepted that oxygen is reduced by cytochrome oxidase, the terminal enzyme in the electron transport chain, in a single 4-electron 4-proton step. However, the discussion about the true mechanism of the process is still...
Article
The oxidation of 6,7-dimethyltetrahydropterin (2-amino-6,7-dimethyl-5,6,7,8-tetrahydro-4-pteridone) was studied by electroanalytical techniques and by its reaction with the one-electron acceptors oxygen and ferricytochrome c. The results indicated that the oxidation process consisted of two one-electron steps, involving the transient generation of...
Article
The application of quinoxaline as a mediator in the indirect electrolysis of various hemoproteins is presented.Quinoxaline is reduced primarily to the radical anion, which can transfer its electron. Metalloproteins can serve as electron acceptors, in which case the metal ion is reduced. Hemoglobin, myoglobin, cytochrome c and cytochrome oxidase are...
Chapter
Binding of dodecyl octaethyleneglycol monoether (C12E8), purified Triton X-100 and dodecyldimethylamino oxide (DDAO) to various integral membrane proteins was studied by chromatographic procedures. Binding capacity decreased in the following order: bacteriorhodopsin ~ mammalian rhodopsin > photochemical reaction center > sarcoplasmic reticulum Ca2+...
Article
An electrochemical synthesis of isomer-free 6-methylpterin from folic acid has been developed. Folic acid is reduced to 7,8-dihydrofolic acid via 5,8-dihydrofolic acid. Under acidic conditions the C(9)N(10) bond in 7,8-dihydrofolic acid is reduced electrochemically, resulting in 6-methyl-7,8-dihydropterin and p-aminobenzoylglutamic acid. 6-Methylp...
Article
Binding of dodecyloctaethyleneglycol monoether (C12E3) and purified Triton X-100 to various integral membrane proteins was studied by chromatographic procedures. Binding capacity decreased in the following order: bovine rhodopsin greater than photochemical reaction center greater than sarcoplasmic reticulum Ca2+-ATPase. The detergents were bound in...
Article
Tetrahydrofolic acid (H4PteGlu) functions as a cofactor for a large group of enzyme-catalyzed reactions. Due to the stereoselective nature of these reactions only one diastereomer can be utilized. In the reduction of L-folic acid to tetrahydrofolic acid a second asymmetric centre is created (at C-6) yielding 2 diastereomers. Tetrahydrofolic acid ca...
Article
An electrochemical synthesis of 5,6,7,8-tetrahydrofolic acid (H4PteGlu) from folic acid (PteGlu) has been developed. In the first step folic acid is reduced, via 5,8-dihydrofolic acid (5,8-H2PteGlu), to 7,8-H2PteGlu. Reduction of the protonated 7,8-H2PteGlu cleaves C(9)-N(10), but reduction of the unprotonated compound at a more negative potential...
Article
The electrochemical reduction of the disulfide bonds in α-chymotrypsin and trypsin is described. After reduction a separation of the respective chains is attempted by gel-filtration. It is shown that biological activity is dependent on the number of disulfide bonds cleaved.
Article
Direct electrolysis of proteins in neutral solutions has been met with limited success, but an electrochemical reduction of disulfide bonds in proteins may be obtained in the presence of a pteridone, which has been previously employed as a mediator in other systems. In certain cases the addition of guanidine hydrochloride made possible a more compl...
Article
Some Macromolecular compounds have been reduced or oxidized electrolytically by means of two mediator systems, both derived from 2-aminopteridone-4. As substrates NAD+ (reduction to NADH), NADH (oxidation to NAD+, cytochrome c (reduction), hemoglobin (reduction to ferrooxyhemoglobin or to ferrohemoglobin), and insulin (reduction of two or three dis...
Article
Some substituted 4(3H)-pteridones have been investigated by classical polarography, cyclic voltammetry, and controlled potential electrolysis; based on these results, the following reaction path for substituted 2-amino-4(3H)-pteridones seems likely. In neutral and slightly alkaline solution the first step is a reversible two-electron reduction to t...
Chapter
In acidic and neutral solution 4-dimethylamino, 4-amino, 4-mercapot, 4-methylrnercapto-derivatives of quinazolines are reduced in a 2 e step to their respective 3,4-dihydro derivatives. This is followed by elimination of the substituent group, resulting in a generation of the 3,4 double bond and formation of quinazoline itself. Quinazoline is then...
Article
Durch elektrolytische Reduktion der Nitroverbindungen (I) bei kontrolliertem Kathodenpotential zu den Benzamidrazonen (II), anschließenden Ringschluß und Ammoniakabspaltung unter Bildung der Dihydrotriazine (III) und Oxidation entstehen die Benzotriazine (IV) (85-96% Ausbeute).

Citations

... Regardless, electroanalytical studies on this topic are very scarce. In 1968, Lund et al. [27] explored the polarographic reduction of BZT, and 20 years later Pedersen et al. [28] analyzed the polarographic reduction of some BZTs in protic and aprotic media. Later on, in 2010, the electrochemical behavior of BZT in a glassy carbon electrode was investigated by Lokesh et al. [29] by cyclic voltammetry (CV) at quite high concentrations (> 60 mg L -1 ). ...
... The conclusion of Nishikimi (9) was apparently supported by Heikkila and Cohen (10), who reported that reduction of ferricytochrome c, a common assay for superoxide, took place during autoxidation of H4B. However, it should be noted that tetrahydrobiopterin directly reduces cytochrome c 3ϩ , with a rather high rate constant (k ϭ 3.4 ϫ 10 6 M Ϫ1 s Ϫ1 ) (11,12). Hence, H4B-dependent reduction of cytochrome c 3ϩ cannot be used as evidence for the occurrence of reaction 2. Likewise, nitro blue tetrazolium reduction as applied by Nikishimi (9) can only be regarded as a weak indication for the intermediacy of superoxide, because Liochev and Fridovich (13) noted that "nitro blue tetrazolium can mediate O 2 . ...
... For permeabilization of lymphoblasts , we would need higher pulse amplitude or number of pulses than for permeabilization of myeloma NS1 cells [35]. On the other hand, it was shown in the case of primary and transformed human amnion cells that primary cells are more sensitive to electric field than transformed cells [36]. Since lymphoblasts are primary cells, they could be more sensitive to electric field even though they are of smaller size. ...
... The only mechanism considered by ICNIRP is temperature rise, which may also occur with 5G exposure, apart from the established non-thermal biological/health effects (42,43). It is well known among experts in the EMF-bioeffects field that the recorded cellular effects, such as DNA damage, protein damage, chromosome damage and reproductive declines, and the vast majority of biological/health effects are not accompanied by any significant temperature rise in tissues (44)(45)(46)(47). The ion forced-oscillation mechanism (48) should be referred to as a plausible non-thermal mechanism of irregular gating of electrosensitive ion channels on cell membranes, resulting in disruption of the cell electrochemical balance and initiating free radical release and oxidative stress in the cells, which in turn causes genetic damage (15,49). ...
... 14 J.C. Trivino Pardo et al. cell proliferation (Velizarov et al., 1999;Kwee and Raskmark, 1999) as well as genotoxic potential effects (Garaj-Vrhovac and Horvat, 1990;Singh, 1995, 1996;Adey, 1997;Phillips et al., 1998) in cell culture and animals. cDNA microarray analysis reveals that some of genes, which act as principal sensors of DNA damage and activate DNA repair signaling cascade, are early activated and their expressions were maintained high since to 48 h. ...
... Based on the what is known in the literature regarding pulse radiolytic, chemical and electrochemical reduction of free pterin [59][60][61][62] the reduction product Sp3 can be proposed as the RePtrH 2 complex. Fig. S10 shows the optimized structure of the RePtrH 2 at the B3LYP/LanL2DZ/PCM (water) level of theory. ...
... Litovitz et al. [13] also found that the same incoherent EMF superimposed on a microwave field blocked the microwave-induced increase in ODC activity in cultured cells. The hypothesis was further supported by the results of the experiments of Raskmark and Kwee [15] showing that an incoherent magnetic field could mitigate the effect of a coherent 50-Hz magnetic field on proliferation of human epithelial amnion cells, and of Lin and Goodman [9] that a superimposed incoherent magnetic field blocked the enhancement effect of a 60-Hz magnetic field on c-myc transcript levels in human leukemia cells. In previous studies, we found that exposure to microwaves caused an increase in DNA single-and double-strand breaks in brain cells of the rat [6, 7]. ...
Reference: DNA-noise
... 9 (40.9%) 0.119 Human Leukocytes, human blood neutrophils, human white blood cells [55,69,75,85,113,114,115,116,117,118 [171,181,182,183,184,185,186,187,188,189,190] [172,191,192,193,194,195,196,197,198] 22 22 (100%) 0 (0%) 2.384e-07 ...
... 9 (40.9%) 0.119 Human Leukocytes, human blood neutrophils, human white blood cells [55,69,75,85,113,114,115,116,117,118 [171,181,182,183,184,185,186,187,188,189,190] [172,191,192,193,194,195,196,197,198] 22 22 (100%) 0 (0%) 2.384e-07 ...
... Here, we have used the comprehensive human cellular protein databases (Celis et al., 1988b to search for one of the most prominent and specific protein markers for transformation of cultured fibroblastic and epithelial cells. Using partial amino acid microsequencing, immunoblotting, and co-migration electrophoresis, we identified gelsolin as one of the most striking downregulated marker proteins. ...