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PubMed1985

Neutron diffraction studies of collagen in fully mineralized bone.

Neutron diffraction measurements have been made of the equatorial and meridional spacings of collagen in fully mineralized mature bovine bone and demineralized bone collagen, in both wet and dry conditions. The collagen equatorial spacing in wet mineralized bovine bone is 1.24 nm, substantially lower than the 1.53 nm value observed in wet demineralized bovine bone collagen. Corresponding spacings for dry bone and demineralized bone collagen are 1.16 nm and 1.12 nm, respectively. The collagen meridional long spacing in mineralized bovine bone is 63.6 nm wet and 63.4 nm dry. These data indicate that collagen in fully mineralized bovine bone is considerably more closely packed than had been assumed previously, with a packing density similar to that of the relatively crystalline collagens such as wet rat tail tendon. The data also suggest that less space is available for mineral within the collagen fibrils in bovine bone than had previously been assumed, and that the major portion of the mineral in this bone must be located outside the fibrils.

Achilles Tendon↗
PubMed1975

The surface chemistry of bone mineral and related calcium phosphates.

A review of the surface chemistry of bone mineral, hydroxyapatite and amorphous calcium phosphate is presented. Small-angle x-ray scattering and low-temperature nitrogen adsorption measurements show the magnitude of bone mineral surface to range from 100-200 m-2/g; the synthetic hydroxyapatite surface can vary from 25-200 m-2/g, while synthetic amorphous calcium phosphate ranges in surface from 20-60 m-2/g, according to the respective preparation conditions. The magnitude of heats of adsorption of certain small molecules (CO, Ar, N2, H2O, CH3OH) on bone mineral and hydroxyapatite show that these are polarizing surfaces that form strong bonds with polar or polarizable molecules; water is hydrogen-bonded to these surfaces with energies ranging from 23 kcal/mole for low coverage to 11 kcal/mole after two full monolayers; concomitantly, methanol ranges from 24 kcal/mole to 9 kcal/mole after the adsorption of one and a half monolayers. Stearic acid will close-pack perpendicularly on bone apatite surfaces when adsorbed from cyclohexane solution in a way reminiscent of the adsorption of this long, straight-chain molecule on water surface. It is believed that these molecules are hydrogen-bonded to electronegative ions on the apatite surface. Synthetic hydroxyapatite has long been used in chromatographic adsorption columns because of the specific bonding capacity the surfaces have for certain proteins and polynucleotides. The metabolic interrelationship of bone mineral and the body fluids is in great part dependent upon the nature and magnitude of mineral surface. From the surface studies described herein it was suggested that a chemical linkage could exist in bone between the mineral surface and certain free polar groups of collagen.

Adsorption↗
PubMed1984

Effects of a training programme for elderly people on mineral content of the heel bone.

Physical inactivity can cause rapid bone loss. Different forms of physical activity are recommended for osteoporosis. The scientific background for such recommendations, however, is usually weak. This study was performed to evaluate whether it is possible to influence bone mineral content in elderly people by regular exercise. A total of 15 women with a mean age of 72 yr took part in a study in which they were given 1 h of training twice a week for 9 mth. Physically inactive patients from an outpatient geriatric unit served as a control group. They were matched in age and did not suffer from diseases that affect the locomotor system. After 10 mth of training no significant increase in bone mineral content, measured in the heel bone, could be found among the participants in the training group. Bone mineral content in the trained subjects was however, significantly higher after this training period than in the control group. The decrease in bone mineral content in the control group was almost the same as in a representative group of the population aged 70 to 79 yr. The cause of the decreased loss of bone mineral content in the physically-active subjects in the study could not be determined, but some contributing factors are discussed. Thus, it appears that physical activity diminishes bone loss due to age and that physical training has a positive effect on bone mineral content compared to that of nonactive controls of the same age. As there are no negative side effects, it has advantages over other forms of therapy, such as pharmacological treatment.

Aged↗
PubMed1988

Correlation of bone mineralization in the radius and humerus of well premature neonates over the first 4 months of life.

To determine how well mineralization correlates in the radius and humerus of neonates, we have measured with photon absorptiometry the bone mineral content (BMC) and bone width (BW) in the humerus and radius of well premature neonates and in the radius alone of well term neonates at birth, 8 and 16 weeks of age. These data allow (1) the correlation of bone mineralization in the humerus and radius at birth and over the first 4 months of life and (2) the correlation between bone mineralization in the radius or humerus at birth and that measured at 8 and 16 weeks in the same bone site. The BMC of the radius was significantly (P less than 0.02) correlated with the BMC of the humerus at birth, 8 and 16 weeks, but the BW of the radius was significantly correlated with the BW of the humerus only at 16 weeks. On the other hand, the BMC of the radius at birth in both term and premature neonates failed to correlate significantly (P = ns) with the BMC of the radius at 8 or 16 weeks. In the humerus, the BMC at birth was significantly (P less than 0.001) correlated with that measured at 8 but not at 16 weeks. These data indicate that the humerus and radius increase in mineral content at a similar rate over the first 4 months of life but that one cannot accurately predict from the BMC at birth what the bone mineral content will be at 8 and 16 weeks of age.

Aging↗
PubMed1992

Studies of matrix vesicle-induced mineralization in a gelatin gel.

Matrix vesicles isolated from fourth-passage cultures of chondrocytes were tested for their ability to induce hydroxyapatite formation in a gelatin gel in order to gain insight into the function of matrix vesicles in in situ mineralization. These matrix vesicles did not appear to be hydroxyapatite nucleators per se since the extent of mineral accumulation in the gel diffusion system was not altered by the presence of matrix vesicles alone, and in the vesicle containing gels, mineral crystals were formed whether associated with vesicles or not. In gels with these matrix vesicles and beta-glycerophosphate, despite the presence of alkaline phosphatase activity, there was no increase in mineral deposition. This suggested that in the gel system these culture-derived vesicles did not increase local phosphate concentrations. However, when known inhibitors of mineral crystal formation and growth (proteoglycan aggregates [4 mg/ml], or ATP [1 mM], or both proteoglycan and ATP) were included in the gel, more mineral was deposited in gels with the vesicles than in comparable gels without vesicles, indicating that enzymes within these vesicles were functioning to remove the inhibition. These data support the suggestion that one function of the extracellular matrix vesicles is to transport enzymes for matrix modification.

Adenosine Triphosphate↗
PubMed1982

Electron microscopical x-ray microanalysis of mineralization nodules and several other tissue compartments in fetal bone.

Several chemical components are involved in bone and cartilage mineralization. Acid glycosaminoglycans (GAG) form one class of these components. In this study, the possible presence of sulfated GAG in areas of beginning bone mineralization was investigated. We analyzed areas containing acid groups, which were made visible with positive colloidal ThO2, by means of x-ray microanalysis. Four tissue compartments were internodular matrix, and noncalcified cartilage matrix. Sulfur proved to be present in a higher concentration in the mineralization nodules than in the osteoid, whereas no significant difference could be demonstrated between the sulfur concentrations in mineralized internodular matrix and osteoid. The ratio of the sulfur content between the mineralization nodules and the cartilage matrix is significantly lower than the corresponding thorium ratio. This difference suggests that acid groups different from sulfate groups occur in a relatively larger amount in mineralization nodules than in cartilage matrix.

Animals↗
PubMed1984

Microdissection--elemental analysis of the mineralizing growth cartilage of the normal and rachitic chick.

The concentrations of elements in avian growth cartilage were studied by electron probe x-ray emission microanalysis (EDX). The cartilage was prepared for analysis by freezing, freeze-fracturing, freeze-drying, and carbon coating techniques. Cells and matrix fragments were removed from the tissue by microdissection with a tungsten needle in a scanning electron microscope (SEM) equipped with a real-time stereoscopic viewing facility. The samples were analyzed in the same SEM by EDX. Elemental analyses were performed on each fragment at a distance from the tissue sample, and hence background radiation due to the sample was eliminated. An important finding was that the intracellular potassium concentration of chondrocytes in calcified cartilage was similar to the levels in the premineralized zones. This observation supports the view that chondrocytes do not die in the process of, or as a consequence of, mineralization of the surrounding matrix. Calcium peaks were seen in the matrix at all levels and in chondrocytes immediately prior to mineralization. In contrast, phosphorus levels were always high in cells and low or absent from the premineralized matrix. At the mineralization front the appearance of a phosphorus peak in the matrix just preceded the deposition of mineral. We propose that the transfer of phosphorus from cell to matrix is a rate-limiting step in mineralization. Finally, when rachitic and normal cartilage were compared, little difference was seen in the profile of either intracellular or extracellular elements. However, in rickets the mineralized matrix remained soft in consistency. We suggest that this may reflect a phosphorus-related calcification defect that prevents growth and interlocking of the apatite crystallites.

Animals↗
PubMedDate not supplied

A stepwise approach to the understanding of extracellular enzyme activity in soil. I. Effect of electrostatic interactions on the conformation of a beta-D-glucosidase adsorbed on different mineral surfaces.

The enzymatic activity of sweet almond beta-D-glucosidase adsorbed on various mineral surfaces was studied. Our aim was to elucidate the mechanism responsible for the observed changes in catalytic activity. The results of the investigation are discussed with reference to the hypotheses generally proposed to explain the well-documented shift in optimal pH of the activity of adsorbed enzymes. By separate determinations of enzymatic activity in a mineral suspension and of its supernatant solution, and comparison with a control without mineral added, we obtained accurate measurements of the catalytic activity of the adsorbed enzyme alone. Different pH profiles of activity profiles were found when the enzyme was adsorbed onto montmorillonite, kaolinite and goethite. The activity profiles, were also found to vary with ionic strength, the pH at which enzyme adsorbed onto the mineral surface, and in the case of goethite, on the nature of the anions in the buffer. Our observations cannot be adequately explained by assuming a more acidic microenvironment at the mineral surface. We postulate that on some mineral surfaces a conformational change is induced in the adsorbed protein, which reduces its catalytic activity. We contend that such conformational changes are due primarily to electrostatic forces.

Adsorption↗
PubMed2005

Combined treatment with PTH (1-34) and OPG increases bone volume and uniformity of mineralization in aged ovariectomized rats.

The combination of PTH with OPG has been proposed as a potential therapy in patients with severe osteoporosis. In the present study, we examined the bone material of aged ovariectomized (OVX) rats treated either with PTH (1-34) or OPG alone or in combination of both. The micro- and nanostructural characteristics of the mineralized bone were evaluated using quantitative backscattered electron imaging (qBEI) and small-angle X-ray scattering (SAXS). Rats (n=68) were either sham-operated or ovariectomized (OVX) at the age of 3 months, and 15 months later, OVX animals were treated either with vehicle, OPG (10 mg/kg), PTH (80 microg/kg) or a combination of both during 5.5 months. All treatments were by subcutaneous injection, 3 days per week. Secondary metaphyseal spongiosa from distal femora was assessed for mineralized bone volume (BV/TV), for the mean Ca-concentration (Camean), the width of the bone mineralization density distribution (Cawidth), as well as the average mineral particle thickness parameter (T) and the degree of alignment of the mineral particles (rho). A remarkable increase of BV/TV up to 139% (P<0.001) was observed in the PTH-treated groups independently of OPG. Camean was slightly increased (+1.7%, P<0.05) in the OPG-treated group. Cawidth was reduced (-6.4%, P<0.01, and -8.9%, P<0.001) in animals treated with OPG and PTH+OPG, respectively. In contrast, Cawidth in sham-operated rats was 16.0% (P<0.001) higher than in OVX. The T parameter was not altered in the trabecular bone within the group of treated and untreated OVX rats. However, the non-ovariectomized animals exhibited a significantly lower T value (-7.1%, P<0.01) with respect to OVX. In conclusion, qBEI and SAXS data of OVX rats suggest that PTH alone was responsible for increase of bone volume, whereas OPG positively influenced the homogeneity and density of mineralization without affecting the nanostructure of the bone material.

Animals↗
PubMed2004

The usage, occurrence and dietary intakes of white mineral oils and waxes in Europe.

Dietary exposures to mineral hydrocarbons were estimated from information about patterns of usage, concentrations in foods and quantities of foods consumed. An industry survey showed that the largest usage of food-grade white mineral oils was in plastics manufacture although the majority are used in non-food applications. The largest volumes of wax usage were in packaging. Conservative estimates indicated that daily intakes of white mineral oils ranged from 0.39 to 0.91 mg/kg bw/day for adults and from 0.75 to 1.77 mg/kg bw/day for children (mean and 97.5th percentiles). Total wax intakes ranged from 0.08 to 0.19 mg/kg bw/day for adults and 0.23 to 0.64 mg/kg bw/day for pre-school children. When usage factors were applied, estimates of chronic intakes of white oils were reduced to 0.09-0.20 mg/kg bw/day for adults and to 0.17-0.39 mg/kg bw/day for children. Total wax intakes were reduced to 0.01-0.02 mg/kg bw/day for adults and to 0.02-0.06 mg/kg bw/day for children. For white mineral oils the principal source of exposure for most consumers was imported de-dusted grain. The principal source of potential wax exposure was from glazing agents on confectionery. There was no evidence of intakes exceeding SCF ADIs for microcrystalline waxes or certain white mineral oils and levels of exposure were similar to those of naturally-occurring mineral hydrocarbons in foods.

Adult↗
PubMed2005

Conditions that regulate the growth of moulds inoculated into bottled mineral water.

The influence of different storage conditions (temperature, illumination, brand of mineral water and storage time) on growth of mould spores was studied. Alternaria alternata, Penicillium citrinum and Cladosporium cladosporioides spores were inoculated in bottles of mineral and mineralised water, packaged in polyethylene terephtalate (PET). The bottles were incubated under different storage conditions. The strains had been isolated from bottled mineral water in a previous study. Storage time was the parameter that had the most important influence in mould growth. The spores grew into visible colonies after 5 month of incubation in bottles just filled, and in a month in bottles that had been stored for 5 month. This could be due to the migration of compounds from PET packaging material into mineral water. This compounds could be used as nutrients (organic matter) for mould growth. The plasticizer additive di-n-butyl phthalate (DBP) concentration in recently bottled mineral water and in 5-month stored bottles was measured. An increase of 20% of DBP concentration was observed. A. alternata and P. citrinum strains were toxicological characterised. Both strains produced mycotoxins in vitro, and P. citrinum produced citrinin in mineral water, posing a potential health risk for consumers.

Alternaria↗
PubMed2004

An evidence-based approach for dietitian prescription of multiple vitamins with minerals.

Dietitians working in hospitals are routinely involved in assessing energy and macronutrient (ie, protein, fat, carbohydrate) requirements of patients. However, complete nutritional therapy requires a comprehensive review of vitamin and mineral requirements. Scientific evidence for vitamin and mineral supplementation is primarily based on healthy, free-living people. This raises clinical challenges for dietitians working with patients whose vitamin and mineral requirements are impacted by various diseases, conditions, and medical treatment. Dietitians are the best-positioned health professionals to lead an evidence-based approach toward recommending vitamin and mineral supplements. The dietitians at the Toronto Rehabilitation Institute were authorized through a medical directive to prescribe multiple vitamins with minerals and to discontinue orders for unnecessary vitamin supplements. This is an ongoing, advanced practice initiative that focuses on the clinical efficacy for and safety of supplementation with multiple vitamins with minerals. It involves assessing the strength of evidence as it emerges in the literature, determining its relevance to specific patient populations in the practice setting and re-evaluating clinical practices for potential applications. When dietitians assume advanced practice initiatives, they are better equipped to deliver high-quality patient care. Simultaneously, state-of-the-art dietetic practice heightens dietitian recognition as a valuable member of the health care team.

Dietary Supplements↗
PubMed2006

In vivo effects of adding singular or combined anti-oxidative vitamins and/or minerals to diets on the immune system of tilapia (Oreochromis hybrids) peripheral blood monocyte-derived, anterior kidney-derived, and spleen-derived macrophages.

Macrophage function is an important factor for resistance to infection and anti-oxidative vitamins and minerals can affect how macrophages function in fish. We report the in vivo effect of adding singular or combined vitamins (A, C, and E) and/or minerals (Se, Zn, Cu, Mn, and Fe) in diets on the immune system of tilapia (Oreochromis hybrids) peripheral blood monocyte-derived, anterior kidney-derived, and spleen-derived macrophages. An optimal dose of vitamins and/or minerals in diets increased macrophage proliferation and protective activity, maintained macrophage viability, increased body weight and length, and increased lysozyme activity, however, at improper doses and combinations of vitamins or minerals a decrease was observed. Furthermore, vitamins and/or minerals at any doses and combinations in diets decreased superoxide and nitric oxide production. Therefore, appropriate doses and combinations of vitamins and/or minerals in diets may increase tilapia macrophages immunity.

Animals↗
PubMed2000

Mineral oil metal working fluids (MWFs)-development of practical criteria for mist sampling.

Not all mineral oil metalworking fluids (MWFs) in common use form stable airborne mists which can be sampled quantitatively onto a filter. This much has been known for some time but no simple method of identifying oils too volatile for customary filter sampling has been developed. Past work was reviewed and experiments were done to select simple criteria which would enable such oils to be identified. The sampling efficiency for a range of commercial mineral oil MWF were assessed by drawing clean air through spiked filters at 2 l. min(-1) for periods up to 6 h before analysis. The physical properties of MWF are governed by their composition and kinematic viscosity was found to be the most practical and easily available index of the potential for sample loss from the filter. Oils with viscosities greater that 18 cSt (at 40 degrees C) lost less than 5% of their weight, whereas those with viscosities less than 18 cSt gave losses up to 71%. The losses from the MWF were mostly aliphatic hydrocarbons (C(10)-C(18)), but additives such as alkyl benzenes, esters, phenols and terpene odorants were also lost. The main recommendation to arise from the work is that filter sampling can be performed on mineral oils with viscosities of 18 cSt (at 40 degrees C) or more with little evaporative losses from the filter. However, sampling oils with viscosities less than 18 cSt will produce results which may significantly underestimate the true value. Over a quarter of UK mineral oil MWFs are formulated from mineral oils with viscosities less than 18 cSt (at 40 degrees C). The problem of exposure under-estimation and inappropriate exposure sampling could be widespread. Further work is being done on measurement of mixed phase mineral oil mist exposure.

Humans↗
PubMed2002

Are mineralized tissues open crystal foams reinforced by crosslinked collagen? Some energy arguments.

Which of the elementary components (hydroxyapatite (HA) crystals, collagen, non-collagenous organic matter, water) do significantly contribute to the ultrastructural elastic stiffness magnitude and anisotropy of mineralized tissues; and how, i.e. through which shapes and assemblages (which micromechanical morphology)? We suggest answers to these questions by analyzing stiffness-volume fraction relationships of wet and dry tissue specimens in the framework of strain energy considerations. Radial stiffness values of both isotropic and anisotropic tissues are found to depend linearly to quadratically on only the mineral volume fraction. This suggests the isotropic contribution of HA to the ultrastructural stiffness. An energy-based analysis of the difference between the axial and radial stiffness values of anisotropic, collagen-rich tissues allows us to assess the collagen elasticity contribution, which is found to depend linearly on the extra-collagenous mineral concentration. These results suggest that collagen and hydroxyapatite are the elementary components governing the ultrastructural elastic stiffness magnitude and anisotropy of bone and mineralized tendons. The elastic stiffness of water and non-collagenous organic matter does not play a significant role. As for the morphological issue, we suggest that mineralized tissues are isotropic open crystal foams; and that these foams are reinforced unidirectionally by collagen molecules which are mechanically activated through tight links between these molecules and HA-crystals. The HA crystals are mechanically activated through stretching and bending in long bone tissues, they are predominantly stretched in mineralized tendons, and bent in hyperpycnotic tissues.

Animals↗
PubMed2001

Lubricants based on renewable resources--an environmentally compatible alternative to mineral oil products.

The development of lubricants like, e.g. engine and hydraulic oils was traditionally based on mineral oil as a base fluid. This fact is related to the good technical properties and the reasonable price of mineral oils. The Report to the Club of Rome (W.W. Behrens III, D.H. Meadows, D.I. Meadows, J. Randers, The limits of growth, A Report to the Club of Rome, 1972) and the two oil crises of 1979 and 1983, however, elucidated that mineral oil is on principle a limited resource. In addition, environmental problems associated with the production and use of chemicals and the limited capacity of nature to tolerate pollution became obvious (G.H. Brundtland, et al., in: Hauff, Volker (Ed.), World Commission on Environment and Development (WCED), Report of the Brundtland-Commission, Oxford, UK, 1987), and the critical discussion included besides acid rain, smog, heavy metals, and pesticides also mineral oil (especially oil spills like the case Exxon Valdes). A disadvantage of mineral oil is its poor biodegradability and thus its potential for long-term pollution of the environment. From the early development of lubricants for special applications (e.g. turbojet engine oils) it was known, that fatty acid polyol esters have comparable or even better technical properties than mineral oil. Subsequently, innumerable synthetic esters have been synthesized by systematic variation of the fatty acid and the alcohol components. Whereas the alcohol moiety of the synthetic esters are usually of petrochemical origin, the fatty acids are almost exclusively based on renewable resources. The physico-chemical properties of oleochemical esters can cover the complete spectrum of technical requirements for the development of high-performance industrial oils and lubricants (e.g. excellent lubricating properties, good heat stability, high viscosity index, low volatility and superior shear stability). For a comprehensive review of their technical properties see F. Bongardt, in: Jahrbuchfür Praktiker, H. Ziolkowsky (Ed.), Verlag für chemische Industrie GmbH, 1996, pp. 348-361. This article will focus on the ecological properties of oleochemical (synthetic) esters. The environmental relevance of oleochemicals in comparison to petrochemicals is discussed, and then the principles of an ecological assessment are described. The ecotoxicological properties and the biodegradability of oleochemical esters are presented. Finally, the ecological properties of the oleochemical esters are discussed with regard to existing environmental classification and labeling systems.

Alkenes↗
PubMed1999

Variation of 66 elements in European bottled mineral waters.

Fifty-six bottled mineral waters bought at random all over Europe were analysed for 66 chemical elements by ICP-AES, ICP-MS and IC-techniques. Results show that there is a wide spread in the chemical composition of mineral waters. The EEC drinking water safeguard values for chemical constituents do not apply to mineral water, although mineral water is increasingly used for general drinking water purposes. Only 15 of the randomly selected 56 mineral waters would fulfil the drinking water regulations for all parameters where action levels are defined. Differences in chemical composition observed between countries or regions are due to geological environment and to different taste or local regulations of what is mineral water. There are indications that element concentrations for some unwanted constituents (e.g. Pb) are higher in waters sold in glass bottles than in those in plastic bottles. Some elements show a clear regional dependency. Studying the large natural variation in concentration for many of the 66 studied elements it becomes clear that we know little about the natural variation of element concentration in water and the health effects of most elements in drinking water.

Chromatography, Ion Exchange↗
PubMed2001

Electrical stimulation influences mineral formation of osteoblast-like cells in vitro.

The aim of the present study was to assess the structure of newly formed mineral crystals after electrical stimulation of osteoblast-like cells in vitro. Pulsed electrical stimulation was coupled capacitively or semi-capacitively to primary osteoblast-like cells derived from bovine metacarpals. Computer calculations revealed that the chosen input signal (saw-tooth, 100 V, 63 ms width, 16 Hz repetition rate) generated a short pulsed voltage drop of 100 microV (capacitive coupled mode) and of 350 microV (semi-capacitive coupled mode) across the cell-matrix layer. Stimulated cultures showed an enhanced mineral formation compared to the non stimulated controls. In cultures exposed to capacitively coupled electric fields and in control cultures nodules and mineralized globules were found. Nodules with a diameter of less than 200 nm covered the cell surface, whereas mineral globules with a diameter of up to 700 nm formed characteristic mineral deposits in the vicinity of the cells similar to biomineral formations occurring in mineralizing tissues. In contrast, large rod-shaped crystals were found in cultures stimulated by semi-capacitive coupled electric fields, indicating a non-physiological precipitation process. In conclusion, osteoblasts in culture are sensitive to electrical stimulation resulting in an enhancement of the biomineralization process.

Animals↗