Showing papers in "Advances in Experimental Medicine and Biology in 1990"
TL;DR: These findings strongly suggest that pathologically relevant lipid hydroperoxide formation consequent to acute or chronic leukocyte activation can be prevented by ascorbate supplementation, provided no free metal catalysts are present.
Abstract: Living is like getting irradiated. This is because we are constantly exposed to oxidants such as Superoxide radicals, hydrogen peroxide, hydroxyl radicals, and singlet oxygen. These reactive oxygen species are generated during normal oxidative metabolism, for example by spontaneous autoxidation of electron transport carriers in mitochondria, or as a result of the action of oxidases.1 One of these oxidases, the NADPH oxidase of polymorphonuclear leukocytes (PMNs) (primarily neutrophils and eosinophils), is pivotal to the body’s defense against pathogenic microorganisms. The immediate product of the stimulus-induced activation of the NADPH oxidase of PMNs is Superoxide anion, whereas subsequent reactions form further oxidants including hydrogen peroxide, hypochlorite, and chloramines.2,3 These oxidants not only kill the invading microorganisms, but also can cause considerable oxidative damage to the host himself. Other sources of oxidants to which we are constantly exposed include our diet, polluted air (particularly from smoking), natural radio active gases,e.g. radon leaching from soils, and some drugs.4,5
268 citations
TL;DR: Atherosclerosis is a complex disease involving a variety of circulating blood components, lipoproteins, and their interactions with the cells and proteins of the extracellular matrix of the artery wall, and it is clear that deposition of cholesterol within the intima plays a central role in the pathogenesis of the atherosclerotic plaque.
Abstract: Atherosclerosis is a complex disease involving a variety of circulating blood components, lipoproteins, and their interactions with the cells and proteins of the extracellular matrix of the artery wall. The end stage lesion, which results in the occlusion of a vessel and/or provides a thrombogenic surface which leads to intravas cular thrombosis is frequently an acellular, fibrotic section of tissue reflecting the end stage of a complicated inflammatory process. The atherosclerotic plaque contains the cellular debris of dead and decaying cells and a variety of substances trapped amidst this debris, including cholesterol, chiefly in the form of precipitated crystals1. While many pathogenic mechanisms must be involved in transforming normal arterial tissue, which contains only a one-or two-layer thick intimal layer, into this highly thickened intima, it is nevertheless clear that deposition of cholesterol within the intima plays a central role in the pathogenesis of the atherosclerotic plaque. Because arterial wall cholesterol is derived almost exclusively from circulating lipoproteins, chiefly in the form of low density lipoproteins (LDL), research must focus on trying to understand the sequence of events by which the plaque develops and by which LDL accumulates2–5. There are many lines of evidence that support the hypothesis that circulating cholesterol, principally in the form of LDL, is central to the atherogenic process and that without “sufficient” plasma LDL levels, the atherogenic process cannot proceed4,6.
148 citations
TL;DR: At least three CaBPs are abundant in various types of nerve cells: calbindin-D28, calretinin, and parvalbumin; in chick brain and retina, the three proteins are largely in different neurons, and co-expression is more common in peripheral sensory neurons.
Abstract: At least three CaBPs are abundant in various types of nerve cells : calbindin-D28, calretinin, and parvalbumin The sequence of chick calretinin, from cDNA clones, is 60% homologous to that of chick calbindin The genomic calretinin gene has also been partially sequenced Calretinin is a protein of 29–30 kilodaltons Antisera have been raised against s-galactosidase-calretinin fusion proteins, and used to compare the distribution of calretinin with that of calbindin by two-colour immunofluorescence Some sections have also been stained for parvalbumin In chick brain and retina, the three proteins are largely in different neurons Calbindin and calretinin are particularly abundant in some sensory nuclei, and co-expression is more common in peripheral sensory neurons In rat brain, and in retinae of rat, cat, and salamander, some of the expression patterns are conserved, but some are not In the chick embryonic retina, some cells show a transient phase of calbindin immunoreactivity during development
141 citations
TL;DR: It is suggested that the assumed stages of short-term, intermediate, and long-term memory, their different time course of origin and decay, their biochemical correlates as well as their sensitivity to interventions reflect the properties of the corresponding cellular mechanisms of a synaptic, synaptosomal and nuclear regulation of memory formation.
Abstract: On the basis of our own experimental data and results from other laboratories then available, we developed in 1972 a working hypothesis on neuronal mechanisms of memory. We suggested that the assumed stages of short-term, intermediate, and long-term memory, their different time course of origin and decay, their biochemical correlates as well as their sensitivity to interventions reflect the properties of the corresponding cellular mechanisms of a synaptic, synaptosomal and nuclear regulation of memory formation (Matthies, 1972).
122 citations
TL;DR: A study of Coley's life’s work will lead to a better understanding of the problems, obstacles and potential solutions in hyperthermia and also it will help morale to realize that the authors are not the first or only ones to have criticisms heaped upon sound and meticulous work.
Abstract: We are pleased to be able to present this summary of the first century of Dr. Coley’s toxins prepared by Helen Coley Nauts. We believe you will agree that this is an objective scientific presentation particularly when one considers the criticism, frequently unfounded, which has been given Coley’s work in the past. Those reading this chapter and working in hyperthermia will find many parallels and similarities with their frustrations and peer criticisms as noted herein. Comparable modes of action will be found for those proposed to explain the benefits of hyperthermia. Possibly with today’s more detailed understanding of the intricate complex immune system, a logical basis can be offered for the “dramatic cures” which in themselves caused skepticism, and Coley’s results can be better understood. A study of Coley’s life’s work will lead to a better understanding of the problems, obstacles and potential solutions we have in hyperthermia and also I suspect that it will help our morale to realize that we are not the first or only ones to have criticisms heaped upon sound and meticulous work. It is gratifying that in recent years Coley is being recognized as the pioneer of cancer immunology.
109 citations
TL;DR: Flavonoid aglycones, members of an ubiquitous class of plant phenols, have often been proposed to act as antioxidants, but only qualitative conclusions could be drawn.
Abstract: Flavonoid aglycones, members of an ubiquitous class of plant phenols, have often been proposed to act as antioxidants.1,2 More recently this activity has been specifically attributed to their radical-scavenging capabilities.3–8 Compounds of various structural features have already been tested,4,7,9,10 but only qualitative conclusions could be drawn.
107 citations
TL;DR: Current knowledge of blood flow and oxygen supply to human tumors, parameters which go hand in hand, and in turn critically determine the cellular metabolic microenvironment of human malignancies are summarized.
Abstract: A great number of malignancies are relatively resistant to radiotherapy, chemotherapy and other non-surgical treatment modalities. A variety of factors are involved in the lack of responsiveness of these neoplasms including an intrinsic, genetically determined resistance and physiological, extrinsic (epigenetic, environmental) factors primarily created by inadequate and heterogeneous vascular networks1–3. Thus, properties such as tumor blood flow and tissue oxygen supply, factors which usually go hand in hand, can markedly influence the therapeutic response. Data on these parameters are mostly derived from rodent tumors. However, fast-growing rodent tumors might not adequately represent the multitude of neoplastic growths encountered in patients. Unfortunately, data on human tumors in situ are scarce and there may be significant errors associated with the techniques used for measurements. This should be kept in mind when comparing available results from the literature.
81 citations
TL;DR: There is sufficient evidence to suggest that adequate antioxidant defense by vitamin E and the other antioxidants can provide protection from the increasingly high levels of free radicals present in the environment due to current lifestyles and the rising concentration of environmental pollutants.
Abstract: Since the discovery of vitamin E over 50 years ago, its role in human health and its biological effectiveness have been under extensive research. It has been established that vitamin E deficiency states exist in humans in specific clinical situations. It is well accepted that vitamin E is the major 1ipid~soluble antioxidant in biological systems, protecting structures and functions of cell membranes from free radical damage. The impact of free radicals on the aging process and development of damage or disease and the protective role of vitamin E and other biological antioxidants in pre venting or delaying these processes is an area of active research.
74 citations
TL;DR: It is pointed out that the protective systems in human milk including the anti-inflammatory components may not be completely delineated, and that little is known of the in vivo fate of the factors and precisely how they protect the recipient.
Abstract: Human milk is characterized not only by a complex host defense system that prevents the colonization and proliferation of common microbial pathogens that may pervade the alimentary tract and respiratory tract of the infant but also by a paucity of inflammatory agents and an array of anti-phlogistic factors. Clinical observations support the notion that the protection provided by human milk involves not only antimicrobial factors, but also anti-inflammatory agents. The major anti-inflammatory agents include enzymes that degrade mediators of inflammation, anti-proteases, lysozyme, lactoferrin, secretory IgA and a number of antioxidants including cysteine, ascorbate, alpha-tocopherol, and beta-carotene. It is pertinent that most of these factors are either absent or poorly represented in cow's milk or other artificial feedings that substitute for breast feeding and that the attainment of adult serum levels of some of these antioxidants in early infancy is dependent upon breast feeding. It may be that the provision of these antioxidants may help to protect the recipient's developing immunologic system which is quite susceptible to oxidant damage. The absence of breast feeding will thus deprive the infant of valuable protection against common enteric-respiratory disorders and their inflammatory consequences. It should be pointed out that the protective systems in human milk including the anti-inflammatory components may not be completely delineated, and that little is known of the in vivo fate of the factors and precisely how they protect the recipient. Those questions should form the basis of important research in the next decades.
73 citations
TL;DR: Present evidence indicates that the three genes of human fibrinogen are linked and are located in a region that extends approximately 45 kb on chromosome 4q23-q32 and are arranged in the order of γ-Aα-Bβ.
Abstract: Fibrinogen is synthesized in the liver by hepatic parenchymal cells and is secreted into the circulation (1). Hepatic synthesis of fibrinogen is constitutive but the rate can be modulated by a number of physiological and nonphysiological factors. The three chains of fibrinogen are encoded by distinct species of mRNA that are derived from the expression of three single copy genes (2, 3). Present evidence indicates that the three genes of human fibrinogen are linked and are located in a region that extends approximately 45 kb on chromosome 4q23-q32 (4). The genes are arranged in the order of γ-Aα-Bβ. The γ and Aα genes are transcribed in the same direction while the Bβ gene is transcribed in the opposite direction.
72 citations
TL;DR: It is suggested that high intensity focused ultrasound may have a role in the treatment of brain tumors based on cell destruction by two mechanisms: (a) direct, by the ultrasound and (b) indirect, by an antineoplastic agent which is delivered via an ultrasonically modified BBB.
Abstract: High intensity focused ultrasound was employed to modify the permeability of the normal feline and canine blood-brain barrier (BBB) to a circulating vial dye — Evans blue (EB) The threshold doses (W sec/cm2) for focally increasing the permeability of the BBB in white matter (WM) and gray matter (GM) were as follows: internal capsule (WM) — 340 to 680; thalamus (GM) — approximately 1326; and caudate nucleus (GM) — 2284 to 2952 In the presence of supralesioning doses of ultrasound, the cross sectional area occupied by the EB was consistently greater than that of the attendant nonhemorrhagic lesion — thus suggesting that BBB changes may be inducible at sublesioning doses These findings, in conjunction with those of others, suggest that high intensity focused ultrasound may have a role in the treatment of brain tumors based on cell destruction by two mechanisms: (a) direct, by the ultrasound and (b) indirect, by ari antineoplastic agent which is delivered via an ultrasonically modified BBB
TL;DR: The antioxidant’s ability to lower the burden of highly reactive free radicals serves to protect the structural integrity of cells and tissues of the immune system as well as other systems in the body.
Abstract: Vitamin E, vitamin C and beta carotene (pro-vitamin A) are essential nutrients which cannot be synthesized in the human body. Each of these nutrients has its own profile of distinct functions. In addition to these unshared functions, these three micronutrients share the capacity to act as antioxidants. As discussed in the introductory chapter, an antioxidant has the ability to stabilize highly reactive, potentially harmful molecules called free radicals. The generation of free radicals has been associated with damage to membranes, enzymes as well as the cell’s nuclear material. The antioxidant’s ability to lower the burden of highly reactive free radicals serves to protect the structural integrity of cells and tissues of the immune system as well as other systems in the body (Machlin and Bendich, 1987).
TL;DR: Progress in dietary fiber research has been slow because of the lack of an agreed definition of fiber, and the development of different techniques for its measurement.
Abstract: Progress in dietary fiber research has been slow because of the lack of an agreed definition of fiber, and the development of different techniques for its measurement. Two main methods have emerged which, by adopting contrasting approaches, include different components of the diet as dietary fiber.
TL;DR: The BBB is a dynamic interface between blood and the central nervous system enabling the brain to keep an optimal internal environment and manipulation of the BBB to allow entry of therapeutic agents may be justified under certain circumstances but should be done with caution.
Abstract: A strict regulation of the neuronal environment is essential for optimal brain function. The blood-brain barrier (BBB), a concept including the morphological and functional mechanisms that restricts or facilitates the passage of substances from blood to brain, enables the brain environment to be regulated relatively independently of fluctuations in plasma concentrations. Although disagreement prevails regarding some specific mechanisms, our knowledge of the BBB physiology has advanced impressively during the last decades (1–13).
TL;DR: The cholesterol-lowering effects of oat products were recognized over a quarter of a century ago and these oat bran-induced changes in serum cholesterol would theoretically reduce risk for coronary heart disease by approximately 10–35%.
Abstract: The cholesterol-lowering effects of oat products were recognized over a quarter of a century ago1. With the possible exception of beans, oat bran lowers serum cholesterol in humans more than any other food2. In metabolic ward studies, incorporating either 50 or 100 g of oat bran daily into a typical American diet lowered serum cholesterol of hypercholesterolemic men by 13–19%2,3. In ambulatory studies of healthy individuals eating their usual diet, providing 50 g of oat bran daily in the form of muffins decreased serum cholesterol by 12–26%4,5. Since every 1% decrease in serum cholesterol reduces estimated risk for coronary heart disease by 2%6, these oat bran-induced changes in serum cholesterol would theoretically reduce risk for coronary heart disease by approximately 10–35%.
TL;DR: It is likely that better physicochemical characterization of dietary fibers and lipids and correlation of these attributes with corresponding physiological effects will inevitably improve the understanding of these vital interactions.
Abstract: It is now well established that dietary fiber is not an inert entity. On the contrary, it can effectively interact with other food components, whether they are macro or micro nutrients. Among the macronutrients, dietary lipids have been studied most extensively in conjunction with dietary fiber. The inclusion of dietary fiber in diet not only displaces lipids, but it also frequently alters or diminishes their physiological and nutritional contributions. This is usually demonstrated in reduced calorie density of the diet, in reduction of blood and hepatic lipids, and in alteration and output of fecal lipids. These changes are of a major significance since they are believed to be beneficial in preventing or reducing serious diseases which include obesity, coronary heart disease as well as certain types of cancer. In order to explain these changes, it is important to understand the interactions and reactions between different dietary fibers and lipids on the molecular basis. Although a number of excellent theories on how dietary fiber reacts or interacts with dietary lipids and how the hypolipidemic effects are achieved have been proposed, our understanding of the mechanism of these interactions is still unsatisfactory. The main reason for this lies in great chemical diversity of existing dietary fibers, and to a lesser degree of lipids, and in extreme difficulty to monitor the reactions which take place in the intestine and in the other parts of the human body. It is likely that better physicochemical characterization of dietary fibers and lipids and correlation of these attributes with corresponding physiological effects will inevitably improve our understanding of these vital interactions.
TL;DR: Calbindin D28K was first described by Wasserman and Taylor (1966) and is now considered as the main direct molecular effect of vitamin D derived hormones on gut epithelial cells.
Abstract: Calbindin D28K was first described by Wasserman and Taylor (1966) and is now considered as the main direct molecular effect of vitamin D derived hormones on gut epithelial cells. It is thought to play a major role in the absorption of calcium from the intestinal lumen and from the distal convoluted tubule of the kidney. The protein is postulated to act as a calcium ferry, facilitating the transport of calcium ions through the cell and keeping the actual free calcium below its toxic level (Jande et al., 1981, McBurney and Neering, 1987). Other cell types containing high amounts of calbindin are the neurons of the central and peripheral nervous systems (Roth et al. 1981), as well as the connected sensory organs (Verstappen et al. 1986), and the alpha and beta cells of the pancreatic islets (Pochet et al. 1987).
TL;DR: The purpose of this report is to present results of work in progress on hyperthermia treatment planning and clinical application of a fourapplicator phased arrayhyperthermia system for heating of large and deepseated tumors.
Abstract: The purpose of this report is to present results of work in progress on hyperthermia treatment planning and clinical application of a fourapplicator phased array hyperthermia system for heating of large and deepseated tumors.
TL;DR: This study analyzes the interaction between cerebellar granule cell neurons (GC) and astroglial cells based on an amino-acid-transmitter mediated regulation mechanism.
Abstract: It is generally accepted that the stimulation of neurotransmitter receptors can lead to the differentiation of neuronal cells1,2. That astroglial cells might play an active role in this developmental process was suggested, but its molecular mechanism still remains elusive. This study analyzes the interaction between cerebellar granule cell neurons (GC) and astroglial cells based on an amino-acid-transmitter mediated regulation mechanism.
TL;DR: The Glial Fibrillary Acidic Proctein is the monomer of a well characterized type of intermediary filaments, the fliofilaments, structurally identified as 10nm in diameter and which are essential components of the cytoskeletal architecture of the astrocyte.
Abstract: The Glial Fibrillary Acidic Proctein (GFAP) is the monomer of a well characterized type of intermediary filaments, the fliofilaments, structurally identified as 10nm in diameter and which are essential components of the cytoskeletal architecture of the astrocyte (see Eng 1980 for a review). The expression of GFAP has been found to be highly specific of this cell type (Eng et al. 1971; Bignami et al. 1972; Uyeda et al. 1972; Gilden et al.1976: Ludwin et al. 1976; Ludwin et al. 1976; Lach and Weinmander 1978) and may therefore be used as an exclusive marker of astroglial cells.
TL;DR: There is good reason to believe that the same agents which in the mature organism function as neurotransmitters also have a differentiating effect on functional parameters, i.e., also act as “functiogens”.
Abstract: It has now become very well established that compounds which in the mature organism function as neurotransmitters may play a major developmental role as “morphogens” (Turing, 1952) during development (Lauder, 1988). In some cases this occurs in regions where the compound in question is not utilized as a transmitter in the mature animal, but in other cases a neurotransmitter seems to be a morphogen for specifically those cells which are destined to become its target cells. Such a system has also been known for a long time in the autonomic nervous system where, for example, innervation directly affects receptor clustering. There is good reason to believe that the same agents also have a differentiating effect on functional (biochemical and biophysical) parameters, i.e., also act as “functiogens”.
TL;DR: An increased population of beneficial intestinal bacteria would help to improve constipation to reduce the production of putrefactive substances.
Abstract: Fructooligosaccharides , containing 1-kestose (GF2), nystose (GF3) and fructofuranosylnystose (GF4), are found undigestible and to be selectively utilized by beneficial intestinal bacteria, particularly by Bifidobacteria. An increased population of beneficial intestinal bacteria would help to improve constipation to reduce the production of putrefactive substances .
TL;DR: There is overwhelming epidemiological evidence that an association exists between cigarette smoking and cardiovascular disease, in particular atherosclerosis, and the component or components of cigarette smoke responsible for this relationship and the mechanisms through which they mediate their effects remain unknown.
Abstract: There is overwhelming epidemiological evidence that an association exists between cigarette smoking and cardiovascular disease, in particular atherosclerosis (Auerbach et al., 1965, 1976; Auerbach and Garfinkel 1980; Dawber et al., 1959; Doll and Peto, 1976; Eastcott, 1962; Kannel et al., 1976; Laing et al., 1981; Murphy and Mustard, 1966; Sackett et al., 1968; Spain and Bradess, 1970; Strong and Richards, 1976). Despite these considerable epidemiological data, the component or components of cigarette smoke responsible for this relationship and the mechanisms through which they mediate their effects remain unknown.
TL;DR: Clarification of the physiological role of monokines as mediators of the host stress response will come from in vivo studies in which the type, sequence of appearance, duration of elevation, and quantification of each monokine is monitored along with ACTH and glucocorticoids, following an appropriate immune challenge.
Abstract: The interleukins (ILs) comprise a group of small proteins or polypeptides with molecular weights in the 15–25 kD range. These polypeptides possess pleiotropic biological activities on immune as well as non-immune cells and can be produced by either cell type. At the present time, recombinant forms for at least IL-lα and β through IL-7 are available for investigative use, and these ILs possess certain overlapping biological activities. The use of the term interleukin is somewhat archaic and limiting since a variety of non-leukocytic cell types produce these molecules or others with similar biological activities. Designations for the ILs, based on cell type of origin, include monokines, lymphokines, and cytokines if they are derived from monocytes, lymphocytes, and non-lymphoid cells, respectively. Finally, there is a trend to refer to all of the above mentioned molecules as cytokines, and an appreciation of the multitude of biological effects induced by the cytokines can be found in several recent reviews (1,2,3,4).
TL;DR: This technique is now used routinely to monitor cerebral oxygenation and haemodynamics in the human newborn infant, using an instrument designed to transilluminate the heads of most newborn infants (Cope and Delpy, 1988).
Abstract: The use of optical spectroscopy for the non-invasive monitoring of tissue oxygenation and metabolism is well established (Chance et al., 1975). Historically because of the high absorption by tissue of light in the visible range, optical monitoring was often restricted to measurements of reflected light (Jobsis et al., 1977). Subsequently Jobsis showed that by using near infrared light (NIR), tissue absorption became sufficiently low to make transillumination of the cat head possible (Jobsis, 1977). In the near infrared region (700–1300 nm) there is sufficient spectral information available to permit changes in the concentration of haemoglobin and cytochrome aa3 to be calculated, and hence changes in the oxygenation state of the brain (Brazy et al., 1985, 1986; Ferrari et al., 1986; Fox et al., 1985). This technique is now used routinely to monitor cerebral oxygenation and haemodynamics in the human newborn infant (Wyatt et al., 1986; Edwards et al., 1988), using an instrument designed to transilluminate the heads of most newborn infants (Cope and Delpy, 1988). This instrument allows for measurements through heads up to 8–9 cm in diameter.
TL;DR: Throughout the biological kingdom copper expresses its function through specific ligands as free copper ion is rapidly complexed, usually specific cuproenzymes, which forms the basis of current understanding of the biochemical function of copper.
Abstract: Copper is an essential metal for proper functioning of all living systems. Biochemical mechanisms have evolved that result in homeostatic balance of copper. This ensures that adequate but not toxic levels are absorbed, transported, utilized, and excreted. Throughout the biological kingdom copper expresses its function through specific ligands as free copper ion is rapidly complexed. These ligands are usually specific cuproenzymes. Knowledge of these cuproenzymes forms the basis of our current understanding of the biochemical function of copper (Prohaska, 1988).
TL;DR: Gram-negative bacteria express in their cell envelope various amphiphilic macromolecules among which the lipopolysaccharides are of special significance for bacterial viability and the interaction of bacteria with host organisms.
Abstract: Gram-negative bacteria express in their cell envelope various amphiphilic macromolecules among which the lipopolysaccharides (LPS) are of special significance for bacterial viability and the interaction of bacteria with host organisms. Together with phospholipids and proteins, lipopolysaccharides form the outer membrane of gram-negative bacteria. This outer membrane has an asymmetric architecture, i.e., lipopolysaccharides are located exclusively in the outer leaflet through which the bacterial cell interacts with its environment.
TL;DR: Functionally, mineralocorticoid receptors and glucocortioid receptors are involved in different aspects of the organization of the stress response, and in conjunction they control the stress responsiveness of the animal.
Abstract: Adrenal glucocorticoid hormones have a potent influence on disparate aspects of brain function. These steroids control cir.cadian and stress-induced aspects of neuroendocrine regulation, affect different aspects of adaptive behavior, and modulate the activity of the neurotransmitter circuitry underlying these processes. During the past twenty years, extensive research has been conducted to elucidate the mechanism of glucocorticoid action in the brain. Great progress was accomplished when it was discovered that adrenal steroids interact with two receptor systems, mineralocorticoid and glucocorticoid receptors, that display different affinities, capacities, specificities, and neuroanatomical localizations in the central nervous system (1–4).
TL;DR: Satellite cells are reserve stem cells of adult skeletal muscle and thus represent a potential source of myogenic cells to use in myoblast replacement therapy of neuromuscular disease and requires knowledge of factors that control the growth and differentiation of satellite cells.
Abstract: Satellite cells are reserve stem cells of adult skeletal muscle and thus represent a potential source of myogenic cells to use in myoblast replacement therapy of neuromuscular disease. Optimal application of this strategy requires knowledge of factors that control the growth and differentiation of satellite cells. Control of satellite cell proliferation is a complex phenomenon determined by the contribution of both positive and negative factors (Fig. 1).
TL;DR: Chemical determination of the content of minerals present in the food do not indicate the amount of the minerals which are available for absorption and utilization.
Abstract: Chemical determination of the content of minerals present in the food do not indicate the amount of the minerals which are available for absorption and utilization. Bioavailability of minerals and trace elements is shown to be affected by both intrinsic and extrinsic factors. Intrinsic factors are those internal to the human or animal and include among others nutritional and health status, sex and age. Components in the diet are the extrinsic factors and could also be described as interactions between the components and the minerals, with either positive or negative effects.