Anthony T. Diplock's research while affiliated with King's College London and other places

Publications (62)

Article
Exposure of 3T3 fibroblasts to Fe reveals a concentration-dependent inhibition of cell proliferation compared to control cells, the apparent threshold for this iron-mediated effect being 5 μM FeII. The inhibition of cell proliferation was accompanied by an enhancement of total malondialdehyde (MDA) levels (as detected directly by hplc) in the cells...
Chapter
Oxygen derived free radicals are produced within the body’s cells by electron transfer reactions usually catalysed by enzymes or transition metal ions, or by ultraviolet or other types of radiation. Afree radical may be defined as any species (atom or molecule) capable of independent existence that contains one or more unpaired electrons. An unpair...
Article
The question of the function of antioxidants in human health can only be resolved when validated markers of oxidative damage are available. Markers allow determination of the effect of antioxidants on damage to DNA, proteins, and lipids. The final goal is the execution of human intervention studies based on markers that are clearly linked to physio...
Article
To examine the effect of co-supplementation with iron and vitamin C on antioxidant status, platelet function and low density lipoprotein oxidation in normal healthy volunteers. The study was carried out with two groups of 20 subjects each acting as their own control, comparing presupplemention with postsupplemention. One group was supplemented with...
Article
1. The Functional Food Science in Europe (FUFOSE) project was introduced, evaluated and accepted by the EU DG XII FAIR Programme as a Concerted Action. Its aim was to develop and establish a science-based approach for the emerging concepts in functional food development. Over the last three years of this EU Concerted Action co-ordinated by ILSI Eur...
Article
This paper assesses critically the science base that underpins the argument that oxidative damage is a significant causative factor in the development of human diseases and that antioxidants are capable of preventing or ameliorating these disease processes. The assessment has been carried out under a number of headings, and some recommendations for...
Article
The effects of co-supplementing healthy volunteers with iron (14 mg/day ferrous sulphate) and vitamin C (either 60 mg/day or 260 mg/day as ascorbic acid) on levels of oxidative DNA damage in white blood cells were studied. The subjects were divided into two groups: one group of 20 volunteers with a higher mean initial level of plasma vitamin C (71....
Chapter
For many years, some scientific experts, and some physicians, have advocated taking large doses of vitamin C, which has been thought to be protective against the common cold and other virus infections. Such dosages are considerably in excess of the recommended daily allowance (RDA) for the vitamin. More recently the indisputable properties of vitam...
Article
Recent research about the role of free radical derivatives of oxygen and nitrogen in biological systems has highlighted the possibility that antioxidants, such as vitamin E, that prevent these processes in vitro may be capable of carrying out a similar function in living organisms in vivo. There is increasing evidence that free radical reactions ar...
Article
Plasma α-tocopherol, β-carotene, serum lipids and their derived ratios were determined in British Civil Servants (n = 7177) at the second medical examination of the Whitehall II Study, a longitudinal study of cardiovascular disease. For plasma α-tocopherol the non-parametric 95% reference interval (90% confidence limits) for the total population wa...
Article
Full-text available
Editor—Margaret P Rayman suggests that fortification of staple foods with selenium should be considered to prevent deficiency of this trace element.1 The following observations may indicate otherwise. In a recent survey in Norfolk 24 hour dietary intakes were measured prospectively in 901 subjects. Average daily intakes of selenium (estimated from...
Article
The relationship between intake of iron with ascorbic acid and their uptake into the plasma and liver of guinea pigs was studied. The influence on the antioxidant/pro-oxidant balance of liver microsomes was also determined. Animals were fed a standard pelleted diet low in iron and ascorbic acid for 35 days. The pellet diet was supplemented by oral...
Article
Endemic myxoedematous cretinism has been associated with combined selenium and iodine deficiency in several areas of Zaire. To determine selenium and iodine status across the country, serum selenium and thyroid function parameters including urinary iodide were determined at prenatal clinics in 30 health centres of rural villages distributed over th...
Article
The purpose of this review is to bring together the different approaches for studying the oxidation of low density lipoproteins and try to identify some critical factors which will permit greater comparability between laboratories. These issues are discussed both in terms of the variety of exogenous mediators of oxidation applied (transition metal...
Article
A human supplementation study was undertaken in order to investigate the correlation between the intake of individual daily dosages of vitamin E (300 mg), vitamin C (250 mg), or beta-carotene (15 mg) of eight week duration and their uptake in vivo in plasma and LDL. The effects of a combined supplement of vitamin E, vitamin C and beta-carotene (Red...
Article
Epidemiologic evidence links high antioxidant status with low risk of degenerative disease. Optimal intakes of antioxidants may not be achievable by diet alone; supplements may be taken, particularly in subgroups of the population at high risk. It is thus necessary to ensure that antioxidant supplements are safe and free from side effects. The toxi...
Article
Interest in a putative disease-preventive role for the so-called antioxidant nutrients derives from a large body of evidence suggesting that oxidative damage is a contributing cause of many life-shortening diseases. Since their use is in an otherwise healthy population, it is important that such agents be virtually free of toxicity. The agents of m...
Article
The total antioxidant-activity (TAA) has been evaluated as a marker of the deterioration of apple juice during storage. Unfortified juice, juice fortified with vitamin C, and an apple ''drink'' (6% juice), to which vitamin C (300 ppm) is added during manufacture, were evaluated. Vitamin C activity represented a minor fraction of the TAA (ca. 1%) of...
Chapter
An antioxidant may be defined as any substance that can delay or prevent the oxidation of a substrate when it is present in small amounts relative to the amount of the substrate. Antioxidant protection consists of three sequential levels of defensive activity. The first level of defense—which is largely enzymatic—involves enzymes, the activity of w...
Article
alpha-Tocopherol (alpha-T) uptake and its relationship to cell proliferation and lipid peroxidation was studied in a baby hamster kidney cell line (BHK-21/C13) and its polyoma virus-transformed malignant counterpart (BHK-21/PyY cells). The principal findings were as follows. (a) The level of lipid peroxidation judged by malondialdehyde (MDA) measur...
Article
Weanling rats were given diets with adequate vitamin E and selenium or deprived of one or the other or both, nutrients. After 28 days, liver mitochondrial and microsomal fractions were prepared and alpha-tocopherol (alpha-T) and selenium measured. alpha-Tocopherol fell by eight-fold in the doubly deficient rats and selenium fell three-fold. Malondi...
Article
A Round Table Discussion was held at the Fourth International Conference on Anticarcinogenesis and Radiation Protection. Scientists from government and academia were brought together to discuss the evidence for the preventive effect of foods, specific nutrients and drugs against cancer, and the most appropriate methods of initiating nutritional can...
Article
There is evidence that free radical damage contributes to the aetiology of many chronic health problems such as emphysema, cardiovascular and inflammatory diseases, cataracts, and cancer. In this review we are not concerned with tissue damage in vivo induced directly by radicals from exogenous sources, such as air pollutants and tobacco smoke, high...
Article
alpha-Tocopherol (alpha-T) uptake and its relationship to cell proliferation and lipid peroxidation was studied in a baby hamster kidney cell line (BHK-21/C13) and its polyoma virus-transformed malignant counterpart (BHK-21/PyY cells). The principal findings were as follows. (i) The level of lipid peroxidation, judged by malondialdehyde (MDA) measu...
Article
This paper considers the factors that affect the bioavailability of selenium to human populations and describes briefly the consequences of an inadequate dietary intake of selenium in the Peoples' Republic of China and in Zaire. A review of human blood selenium concentrations worldwide reveals very large differences in the apparent dietary status o...
Article
Full-text available
Studies were performed to assess the role of combined selenium and iodine deficiency in the etiology of endemic myxedematous cretinism in a population in Zaire. One effect of selenium deficiency may be to lower glutathione peroxidase activity in the thyroid gland, thus allowing hydrogen peroxide produced during thyroid hormone synthesis to be cytot...
Article
Studies on glutathione (GSH) metabolism in an established baby hamster kidney fibroblast cell line (BHK-21/C13) and in its polyoma virus-transformed counterpart (BHK-21/PyY) have revealed a significant stimulation of intracellular GSH peroxidase (GSHpx) activity (selenium-independent plus selenium-dependent) by alpha-tocopherol supplementation (14...
Article
Severe selenium deficiency has been documented in northern Zaïre, already known as one of the most iodine deficient regions in the world and characterized by a predominance of the myxoedematous form of cretinism. This has been attributed to the double deficiency of essential trace elements. A short selenium supplementation programme was conducted i...
Article
Studies on glutathione metabolism in an established baby hamster kidney cell line (BHK-21/C13) and in its polyoma virus-transformed counterpart (BHK-21/PyY), have revealed a significant stimulation of intracellular glutathione peroxidase activity (Se-independent plus Se-dependent) by alpha-tocopherol supplementation (14 microM). This stimulation wa...
Article
From numerous publications on the "prophylactic" and "therapeutic" use of vitamin E, it may be concluded that the toxicity of vitamin E is very low. It has been demonstrated in animal experiments that vitamin E has neither mutagenic, teratogenic nor carcinogenic properties. Based on studies in humans, a daily dosage of 100-300 mg vitamin E can be c...
Article
Selenium and seleno dependent glutathione peroxidase (GPX) deficiency has been described in endemias of myxedematous cretinism. In northern Zaire, a selenium supplementation trial has been conducted. Beside correcting the GPX activity, two months of selenium supplementation was shown to modify the serum thyroid hormones parameters in clinically eut...
Article
Interest in free radical events has stimulated speculation that their disorder may be involved in a number of diseases. The reduction of dioxygen to water involves several active intermediates. The control of this depends on the integrity of an enzymatic system that requires adequate intake of selenium, copper, zinc, and manganese; if their level o...
Article
Full-text available
Selenium status was determined in an endemic-goiter area and in a control area of Zaire. Compared with the reference values of a noniodine-deficient area, serum selenium in subjects living in the core of the northern Zaire endemic-goiter belt (Karawa villages) was seven times lower in 52 school-children and similarly low in 23 cretins; erythrocyte...
Article
There are excellent theoretical reasons why the mineral nutrients selenium, manganese, copper and zinc, known as the antioxidant minerals, may be involved in the prevention of cancer aetiogenesis. The biochemistry is discussed of the part played by the antioxidant minerals, in the wider context of the other dietary antioxidants vitamins A, E and C,...
Article
Generation of protein autofluorescence in the visible region during oxidation by O free-radical (OFR) attack is discussed. It is demonstrated briefly that specific oxidized products of amino-acids are retained in the protein backbone after exposure to OFR generating systems in vitro, and that in aerated soln., oxidized tryptophan residues confer th...
Article
Selenium concentrations were measured in the serum of 244 patients attending the Norfolk and Norwich Hospital, and 246 attending the James Paget Hospital in Gorleston, Norfolk. Both the mean and the median serum selenium concentration was lower in Gorleston than in Norwich, the difference being much greater in women than in men. Whereas the seleniu...
Article
We have investigated the effects of iron overload in vivo on the tocopherol levels and the extent of lipid peroxidation in rat liver microsomes and their response to subsequent oxidative stress in vitro. The results demonstrate a direct correlation between consumption of antioxidant defences and the induction and extent of malondialdehyde productio...
Article
(1) Rats were given a diet deficient in vitamin E and selenium, or diets supplemented with either or both of these nutrients. The livers were subfractionated by standard procedures, and the purity of the fractions was assessed by marker enzyme techniques. α-Tocopherol was measured and profiles of phospholipid fatty acids were determined. (2) All th...
Article
(1) A method was devised for the subfractionation of normal rat liver and for the subfractionation of the mitochondrial fraction into inner and outer membrane fractions. The purity of the fractions was assessed using marker enzyme measurements. (2) α-Tocopherol was measured in all the fractions by a sensitive HPLC technique. Profiles of phospholipi...
Article
Preliminary experiments confirmed the work of others showing that the total glutathione peroxidase (GSH-px) activity of rat liver supernatant fraction may be resolved into two peaks of activity (peaks I and II) by gel filtration, and that peak I is the selenium-containing enzyme and peak II is another peroxidase indistinguishable from glutathione S...
Article
Selenium is an element that is both essential, at low levels of dietary intake, and toxic, at high levels, to man and a wide range of animals. The purpose of the communication is to review the evidence for the involvement of hyper‐ and hypo‐selenosis in the aetiology of cancer. High levels of selenium intake have been blamed for an increase in canc...
Article
Free radical-catalyzed lipid peroxidation is a continual biological process, which if unchecked may cause damage to cellular and intracellular membranes, resulting not only in changed membrane structure but also in the destruction of the functional integrity of membrane-bound enzymes. Vitamin E, alone and in concert with the selenium-containing enz...
Article
1. Vitamin E and selenium deficiencies were produced in the Pekin duckling ( Anser cinerens ) and were characterized by the development of lesions after 14 d in gizzard, intestine, heart and skeletal muscle. 2. The activities of glutathione peroxidase ( EC 1.11.1.9), using hydrogen peroxide and cumene hydroperoxide as substrates, glutathione-S-tran...
Article
Erythrocyte and plasma glutathione peroxidase levels were measured in 12 patients with multiple sclerosis, in 11 age- and sex-matched normal subjects, and in 12 similarly matched patients with other neurological diseases. No difference was found in the enzyme levels in the three groups, indicating that glutathione peroxidase deficiency is not a con...

Citations

... The content of dityrosine, kynurenine, N-formylkynurenine and tryptophan was assessed fluorimetrically. The characteristic fluorescence at 330/415, 365/480, 325/434, and 295/340 nm, respectively, was measured [36,37]. Immediately before determination, saliva and plasma samples were diluted in 0.1 M H 2 SO 4 (1:5, v/v) [32]. ...
... In fact, it is very difficult to have a precise and universally accepted definition of these foods. Consequently, it has been suggested to understand the term "a functional food" as a new idea, rather than a defined product [Bellisle et al., 1998;Diplock et al., 1999;Roberfroid, 2000Roberfroid, , 2002. Further, in a more practical way, a functional food is defined as: ...
... "A food can be regarded as 'functional' if it is satisfactorily demonstrated to affect beneficially one or more target functions in the body, beyond adequate nutritional effects, in a way that is relevant to either an improved state of health and well-being and/or reduction of risk of disease. Functional foods must remain foods and they must demonstrate their effects in amounts that can normally be expected to be consumed in the diet: they are not pills or capsules, but part of a normal food pattern" [6]. ...
... HPLC analysis was performed with a Hewlett-Packard 1100 system (Hewlett-Packard, NJ, USA) according to the method of Glowacki et al. [20] and Bald et al. [21]. Free total thiol groups in plasma proteins with 5,5 0 -dithio-bis(2-nitro-benzoic acid) were determined [22]. ...
... Determination of the glutathione (one of main factors responsible for the antioxidative mechanism in the body) concentration is usually performed as a measure of thiol groups content using Ellman's reagent (5,5'-dithio-bis-(2-nitrobenzoic acid); DTNB). The method was developed in 1991 by Diplock [24] et al. To achieve this goal, a reaction between compounds containing thiol groups from patients' serum and 0.1 M DTNB in 10 mM sodium-phosphate buffer pH 8.00 was conducted with the presence of 10% SDS. ...
... A free radical is a molecular species containing an unpaired electron and is engaged in bacterial, fungal, and parasitic infections, inflammation, atherosclerosis, lung damage, reperfusion injury, aging, neoplastic, and cardiovascular and autoimmune disorders [22,23]. The results of our study demonstrated that ECME exerted free radical scavenging activity in vitro models including DPPH • and FIC assays. ...
... Oxidative stress is one of the main causes of serious diseases such as degenerative changes in the aging process, cancer, atherosclerosis, rheumatoid arthritis, cardiovascular and autoimmune diseases, and neurodegenerative disorders such as Alzheimer's and Parkinson's (Diplock 1996;Geronikaki and Gavalas 2006;Silva et al. 2018). The search for new antioxidants that can actively react with free radicals and protect biomolecules from oxidative damage is continuing (Diplock 1996;Silva et al. 2018). ...
... The high content of α-tocopherol in table olives (Malheiro et al., 2012;Sakouhi et al., 2008) reinforces the nutritional value of this product because this substance provides protection from free radicals (Cheeseeman and Slater, 1993;Kamal-Eldin and Andersson, 1997) and prevents cancer and arteriosclerosis (Armstrong et al., 1997;Caruso et al., 1997;Nicolaiew et al., 1998). Table olives are not only an important source of bioactive compounds, as described above; since they are fermented products, they are also potential functional foods as carriers of probiotic lactic acid bacteria (Argyri et al., 2013;Peres et al., 2014a). ...
... Selenium deficiency, although less prevalent than iodine and zinc deficiencies, has also been reported in some areas of the globe (Levander 1987). Current evidence indicates that the simultaneous occurrence of nutritional deficiencies of more than one of these micronutrients could be more common than previously considered (Diplock 1992, Vanderpas et al. 1993. These situations may have important implications regarding the form in which such deficiencies are expressed. ...
... This is a nondestructive technique that relies on the fluorescence of protein fluorophores after excitation by UV light. 9,[57][58][59][60][61] Lenses are placed in distilled water in a specially designed cylindrical quartz cell that allows reproducible orientation of the lens to the incident light beam to be achieved. An incident (excitation) beam wavelength of 280 nm is used and the height of the resultant fluorescence (emission) peak monitored at approximately 340 nm. ...