Fred Wiegant

Utrecht University | UU

Informing students about their progress in comparison to their peers has been widely used in educational research as a strong motivational factor, effective gamification technique and means for adaptive guidance to learning material. A typical social comparison interface helps students weight their individual levels against the average levels of ot...

Collaborative learning is a widely used instructional method, but its learning potential is often underused in practice. To identify the importance of various factors underlying effective collaborative learning, we selected and analyzed five different life science courses with successful collaborative learning and focused on factors that, according...

Collaborative learning is a widely used instructional method, but the learning potential of this instructional method is often underused in practice. Therefore, the importance of various factors underlying effective collaborative learning should be determined. In the current study, five different life sciences undergraduate courses with successful...

Background Phials containing high dilutions of homeopathic remedies are commonly utilized in diagnostic tools in combination with electro acupuncture measuring electrical conductivity of the skin. The present research aimed to elucidate the interaction of the homeopathic remedy and the human organism. Method The study protocol included the transit...

The pathophysiology of disease has dominated the biomedical world during the past few centuries. Lately, however, renewed interest has been observed in the phenomenon of 'health'. Even though this phenomenon has been defined in many different ways, an encompassing definition that can be aptly used by the scientific medical community to measure and...

In contrast to the detrimental action of severe stress conditions, the beneficial effects of mild stress, known as hormesis, is increasingly discussed and studied. A variety of applications for hormesis in risk assessment processes, anti-ageing strategies and clinical therapies have been proposed. The molecular mechanisms underlying the phenomenon...

The health benefits of consuming organically produced foods compared with conventional foods are unclear. Important obstacles to drawing clear conclusions in this field of research are (1) the lack of a clear operational definition of health and (2) the inability to distinguish between different levels of health using valid biomarkers. In this pape...

Cooperative learning and team-based learning have been widely recognized as beneficial strategies to improve all levels of education, including higher education. The benefits have been widely researched and are now well-established (Johnson et al.; Michaelsen, Bauman Knight, et al.; Michaelsen & Sweet; Slavin; Springer et al.). The studies have ind...

Postexposure conditioning, as a part of hormesis, involves the application of a low dose of stress following exposure to a severe stress condition. The beneficial effect of a low level of stress in postconditioning hormesis is illustrated by a number of examples found in experimental and clinical research. Depending on whether the low-dose stress i...

A beneficial effect of applying mild stress to cells or organisms, that were initially exposed to a high dose of stress, has been referred to as 'postconditioning hormesis'. The initial high dose of stress activates intrinsic self-recovery mechanisms. Modulation of these endogenous adaptation strategies by administration of a subsequent low dose of...

This article reports on a one-semester Advanced Cell Biology course that endeavors to bridge the gap between gaining basic textbook knowledge about cell biology and learning to think and work as a researcher. The key elements of this course are 1) learning to work with primary articles in order to get acquainted with the field of choice, to learn s...

Postexposure conditioning, as a part of hormesis, involves the application of a low dose of stress following exposure to a severe stress condition. Depending on whether the low-dose stress is of the same type of stress or is different from the initial high-dose stress causing the diseased state, postconditioning can be classified as homologous or h...

This paper describes the results of a research program focused on the beneficial effect of low dose stress conditions that were applied according to the similia principle to cells previously disturbed by more severe stress conditions. In first instance, we discuss criteria for research on the similia principle at the cellular level. Then, the homol...

In the present study, the effect of plant adaptogens (Rhodiola rosea and ADAPT-232) on human photon emission has been determined. In a randomized double blind placebo-controlled study, 30 subjects were randomly assigned to three groups: one group (n = 10) taking placebo pills, one group (n = 10) taking Rhodiola rosea (SHR-5) pills and one group (n...

Extracts of plant adaptogens such as Eleutherococcus senticosus (or Acanthopanax senticosus) and Rhodiola rosea can increase stress resistance in several model systems. We now show that both extracts also increase the mean lifespan of the nematode C. elegans in a dose-dependent way. In at least four independent experiments, 250 microg/ml Eleutheroc...

Convincing evidence supports a role for oxidative stress in the pathogenesis of many chronic diseases. The model includes the formation of radical oxygen species (ROS) and the misassembly and aggregation of proteins when three tiers of cellular defence are insufficient: (a) direct antioxidative systems, (b) molecular damage repairing systems, and (...

Grundvoraussetzung für eine erfolgreiche homöopathische Behandlung ist die Anwendung des Simile-Prinzips. An der Fakultät für molekulare Zellbiologie, Universität Utrecht, wurden vor kurzem erstmals die elementaren Mechanismen der Simile-Wirkung an Zellkulturen experimentell aufgezeigt. Toxische Substanzen haben in hohen Konzentrationen eine Störun...

Disorders in memory and other cognitive functions in Alzheimer's disease (AD) may result from an exhaustion of adaptive reserves in the brain. Therefore it is a challenge to find methods to increase the adaptive reserve of the organism to combat AD. Excitotoxicity, Ca2+ homeostasis disruptions, oxidative stress, disturbed synthesis of NO, and impai...

Despite the urgency of the problem of prevention and treatment of neurodegenerative processes underlying Alzheimer's disease (AD) and other severe disorders of the central nervous system, therapeutic and prophylactic potential of drugs is yet insufficient. Numerous adverse effects of the drugs, which might improve cognitive function in patients wit...

In order to demonstrate that high dilutions of histamine are able to inhibit basophil activation in a reproducible fashion, several techniques were used in different research laboratories. The aim of the study was to investigate the action of histamine dilutions on basophil activation. Basophil activation was assessed by alcian blue staining, measu...

Dosed adaptation to environmental factors is an efficient non-drug means for increasing the resistance of organs or the body as a whole. We demonstrated earlier that nitric oxide (NO) plays an important role in adaptive defense of the organism, in particular due to activation of heat shock protein (HSP) synthesis. A key question remained open--to w...

The main purpose of the studies presented in this paper is twofold: 1) to evaluate whether phyto-adaptogens (Acanthopanax senticosus and Rhodiola rosea) are able to exert a protective action against stress-induced death of embryos of the pond snail Lymnaea stagnalis; and 2) whether a possible protective action by phyto-adaptogens can be explained b...

The purpose of this study is to reinvestigate the heat shock response in cells treated with the antimetabolite azetidine-2-carboxylic acid (azetidine), an analogue of proline. Previous studies could not clearly discriminate between the progressive thermosensitization caused by amino acid analogues and a parallel induction of thermotolerance by heat...

The purpose of this study is to reinvestigate the heat shock response in cells treated with the antimetabolite azetidine-2-carboxylic acid (azetidine), an analogue of proline. Previous studies could not clearly discriminate between the progressive thermosensitization caused by amino acid analogues and a parallel induction of thermotolerance by heat...

A mild increase in temperature that does not exert an effect on tolerance development or synthesis of heat shock proteins (Hsps) in control cells can stimulate these processes when applied to cells that have previously been heat shocked. To study the underlying mechanism of this effect, H9c2 cells were stably transfected with the gene encoding fire...

1 A brief and moderate heat shock to Reuber H35 hepatoma cells causes a rapid increase in the synthesis of heat shock proteins (hsp) and initiates the development of thermotolerance, which results in an increased ability to survive exposure to otherwise lethal temperatures. 2 We now demonstrate that low doses of various chemical stressors (arsenite...

The concentration-dependent effect of various nitric oxide donors on synthesis of different heat shock proteins was evaluated in Reuber H35 hepatoma cells and their heat shock protein-inducing ability was compared with the effect of a heat shock. A 6 h incubation of H35 cells with the dimeric (diamagnetic) form of dinitrosyl iron complex with gluta...

The stably transfected rat cell line HR24 expressing high levels of the inducible human hsp70 and its parental cell line Rat-1 were used for in vivo studies to analyse the role of hsp70 during thermal protein denaturation and the subsequent renaturation. In order to monitor denaturation and renaturation of a cellular protein in vivo, both cell line...

In this paper, the pattern of induction of heat shock proteins (hsps) was studied in cultured Reuber H35 rat hepatoma cells by sequential application of different stressors. We analyzed whether a specific stress condition is able to induce an enhanced sensitivity to a subsequent application of a low dose of either the same or another stressor (self...

The aim of our studies is to understand the stimulation of self-recovery processes at the cellular level by compounds which are applied according to the similia-principle. In order to induce self-recovery, cells are exposed to mildly damaging conditions. In our research a non-lethal concentration of sodium arsenite or a mild heat shock was used whi...

The stimulation of self-recovery by applying the similia-principle is considered to be the essence of homeopathy. The similia-principle indicates that a substance which causes certain symptoms in a healthy organism, may be applied in a curative sense to a diseased organism with identical symptoms.

This article has been originally drafted by F Wiegant, D Koster and Ton Nicolai as a report of the European Committee for Homoeopathy to the Directorate General XII of the European Commission in Bruxelles. Since the article contains important contributions regarding assessments and standards in research into homoeopathy, it has been found that it w...

The essence of homoeopathy is considered to be the stimulation of recovery and healing processes by application of compounds according to the similia principle. A research program was developed to study this fundamental principle in biological research at the cellular level. This research program has been subdivided in a number of sequential phases...

The similia principle is considered to be the essence of homeopathy. This article describes a research program for study of the similia principle in cultured mammalian cells. This systematic program with its rather simple research model was set up ultimately to contribute to the design of studies of the similia principle with more complex organisms...

The aim of this study was to determine whether the cadmium-induced cellular stress response can be modulated by the subsequent application of low concentrations of the same ion. It is shown that exposure of Reuber H35 rat hepatoma cells to cadmium concentrations of 10 or 30 μM for 1 h leads to a biphasic change in their sensitivity towards a second...

The aim of our studies is to understand the stimulation of self-recovery processes at the cellular level by compounds which are applied according to the similia-principle.

The existence of stressor-specific induction programs of heat shock proteins (hsps) leads us to analyze the possible occurrence of a stressor-specific tolerance induced by either heat shock, arsenite, or cadmium. As a measure of this tolerance re-induction of hsps was studied. In this paper, we tested whether the refractory state is either valid fo...

In this article, it will be described how the similia principle can best be studied in fundamental research. To this end, two questions are raised: ‘What is known about the regulatory principles on which homeopathic treatment is directed?’ and ‘In what kind of conditions can these regulatory principles best be studied?’ With respect to the first qu...

In this study we compared sensitization to x-rays by heat or sodium arsenite and the effect of an induced heat or arsenite resistance on radiosensitization. Treatment of Reuber H35 hepatoma cells with either heat or arsenite causes a dose-dependent radiosensitization. Based on a comparison of isosurvival doses for arsenite and heat, arsenite causes...

This paper describes how the similia principle can be studied best in fundamental research. 2 questions are raised: ‘What is known about the regulatory principles at which homoeopathic treatment is directed?’ and ‘In what kind of conditions can these regulatory principles be studied best?’ The vision of Hahnemann and ideas related to the ‘field con...

The present study is aimed at determining whether the induction of heat-shock protein (hsp) synthesis, heat-shock mRNAs, and tolerance development after arsenite application has been sensitized to low concentrations of arsenite in Reuber H35 rat hepatoma cells. Using a step-down arsenite treatment, consisting of a 1-hr pretreatment with 100 or 300...

Stress proteins (heat shock proteins, HSPs) have been proposed as markers for toxicity. This study has focussed on the pattern of HSP synthesis in relation to cytotoxicity and their dependence on doses of cadmium chloride. We investigated the relationship between cadmium-induced expression of heatshock genes, inhibition of protein synthesis and cel...

The concept that free radicals mediate vascular abnormalities in diabetes has been debated. This study examines the relationship between serum free radical activity and glycaemic regulation. A cross-sectional assessment is presented of the chemiluminescence of blood serum, long term glycaemic control (HbAlc, fructosamine) and blood glucose concentr...

In order to determine whether induction of specific stress proteins is dependent on a given stressor and whether induction of these proteins is linked to survival, Reuber H35 rat hepatoma cells were exposed to five different environmental stressors (heat shock, arsenite, cadmium, dinitrophenol and ethanol). The effect of these stressors was studied...

Normal and thermotolerant H35 cells were submitted to step-down heating (SDH). SDH can significantly reduce the induction and expression of thermotolerance. For SDH a sensitizing treatment (ST) at 44.6 degrees C was followed by a test treatment (TT) at a lower hyperthermic temperature. The comparison between the thermotolerant and non-thermotoleran...

We studied the influence of specially prepared highly diluted thyroxine on the spontaneous tendency of juvenile frogs, which were at the end of thyroxine-controlled metamorphosis, to leave the water and climb onto land. The test dilution with a thyroxine concentration beyond Avogadro's value (dilution thyroxine D30) and the reference (dilution wate...

In the past many scientists have published papers on hormesis, on molecular stress responses, and on the similia principle in homoeopathy. Very few, however, have stressed a common base of interdependence of these fields. Reviews the most important of these studies to demonstrate their evolution and their mutual importance. Furthermore, a multidisc...

Mammalian cells exhibit increased sensitivity to hyperthermic temperatures of 38-42 degrees C after an acute high-temperature heat shock; this phenomenon is known as thermo-sensitization or the step-down heating effect. In order to determine whether the increase of heat shock mRNA after heat stress can be thermosensitized, we studied the induction...

The present studies investigate the influence of extremely dilute thyroxine on the climbing activity of juvenile highland frogs and on two transitions in the metamorphosis of these animals. The highly diluted thyroxine (10-30, 1.125 × 10-30M, “D30”) to a small but statistically significant extent slows down the climbing activity of juvenile frogs,...

Our data show that a short incubation with arsenite (30–300 μM) induces a biphasic change in ceSlular sensitivity towards a second exposure to arsenite. A transient sensitization was followed by the development of self-tolerance. Sensitization was measured using the step-down protocol; i.e., application of a high dose of arsenite pretreatment (100...

In this work, we demonstrated that a nonlethal dose of arsenite administered to quiescent C3H10T1/2 fibroblasts can enhance the mitogenic effect of suboptimal concentrations of serum. The mitogenic effect was dependent on the serum concentration and on the time interval between the administration of arsenite and that of serum. This suggests that mi...

The experiments investigate the influence of extremely dilute thyroxine (T4) in special 'homœopathic' preparation (dilution T4.30x) on the spontaneous tendency of juvenile frogs to leave the water and climb on land. Climbing activity was suppressed by dilution T4.30x, with statistical significance both in comparison to the effect of the 'potentized...

A conditioning treatment of 30 min at 42 degrees C or 43 degrees C, followed by a 4-h recovery period at 37 degrees C, induces thermotolerance state in the cytoskeleton of Reuber H35 hepatoma cells and N2A neuroblastoma cells. Evidence for the involvement of heat shock proteins in the development of thermotolerance in the cytoskeleton has been obta...

The structural interaction of the epidermal growth factor (EGF) receptor and the cytoskeleton of A431 cells has been studied using a monoclonal anti-EGF receptor antibody. This has been done with immunogold labeling using a variety of electron microscopical preparation procedures and EGF binding studies. By providing an image of the membrane-associ...

The structural interaction of the epidermal growth factor (EGF) receptor and the cytoskeleton of A431 cells has been studied using a monoclonal anti-EGF receptor antibody. This has been done with immunogold labeling using a variety of electron microscopical preparation procedures and EGF binding studies. By providing an image of the membrane-associ...

To visualize the localization of cell surface constituents in relation to the plasma membrane-associated filament network, we developed a method based on a combination of immunogold labeling and dry-cleaving. For labeling we used trinitrophenyl-derivatized ligand, anti-TNP antibodies, and protein A-coated colloidal gold. Dry-cleaving (Mesland, D. A...

In this paper we describe the use of a number of complimentary methods to visualize cytoplasmic and cell-surface located epidermal growth factor (EGF) receptors in cultured A431 cells. Cryo-ultramicrotomy in combination with immuno-gold labelling will be shown to provide an excellent method in visualizing cytoplasmic located EGF receptors in additi...

The role of calmodulin (CaM) in cellular heat injury of neuroblastoma N2A and hepatoma H35 cells has been investigated, using specific calmodulin-inhibiting drugs (Trifluoperazine, Compound 48/80 and Calmidazolium). These CaM-specific drugs potentiate hyperthermia-induced cell killing, suggesting CaM to be involved in processes aimed on the repair...

Tetanic but not low frequency stimulation of the perforant path in rat hippocampal slices results in changes in the metabolism of phosphoinositides and phosphatidic acid. The phosphorylation of other, non-inositol lipids was not affected by the high frequency stimulation. The observed changes in phosphoinositide metabolism are complex and biphasic,...

Heat treatment at 42 degrees C of cultured Reuber H35 rat hepatoma cells induced both a rapid decrease of the rate of protein synthesis and the rounding up of the cells. Reincubation at 37 degrees C resulted in a gradual flattening of the cells, resumption of protein synthesis, and the synthesis of heat-shock proteins. During the recovery period ce...

Induction of DNA synthesis by serum and amino acids has been investigated in cultured Reuber H35 hepatoma cells. Commitment of DNA synthesis was found to occur 6-8 hours before the actual start of this synthesis. The rate of initiation of DNA synthesis is proportional to the stimulation of protein synthesis by serum and/or amino acids. The increase...