Neutron activation analysis of bulk and selected trace elements in bones using a low flux SLOWPOKE reactor

Role of calcium and phosphorous concentration as an intrinsic factor in the development of skull fracture following road traffic accidents

INTRODUCTION

Traumatic brain injury (TBI) or head injury is one of the leading causes of morbidity and mortality globally. TBI includes a fractured skull as an indicator of insult which can affect the treatment outcome as well. The development of any fracture depends on a combination of factors defining the intrinsic properties of the bone and the extrinsic factors related to the impact. A decrease in bone mass secondary to deficiency of calcium (Ca) and phosphorus (P) can be a significant factor intrinsic to the skull bone, which can modulate the outcome of the impact by increasing the susceptibility of bones towards fractures. We undertook this research to find out whether or not the Ca and P concentration in skull bone has a role to play as an intrinsic factor, in the development of skull fracture following Road Traffic Accidents (RTAs).

METHODOLOGY

In this case-control study conducted for two years, we collected 94 bone samples, i.e. 47 each, from skull bones with head injuries following RTA, with (case) and without (control) fracture of the skull. The elemental analyses for the bony concentration of Ca and P in both the groups were then compared using energy dispersive X-ray (EDX). Unpaired t-test and Fisher's exact test was used for statistical analysis.

RESULTS

The elemental analysis of bones provided evidence that suggests that whilst; Ca is the only mineral that appears to have a significant correlation with the development of fracture skull, the overall Ca: P ratio of less than 1.99 increases the chances of skull fracture by 3.9 times.

CONCLUSIONS

Both individual bony Ca concentration and Ca: P ratio can be regarded as important intrinsic factors for the development of skull fracture.

Effect of zinc addition on the immune response and production performance of broilers: a meta-analysis

Objective

This study performed a meta-analysis of published trials to determine the effects of zinc on the immune response and production performance of broilers.

Methods

A database was built from published literature regarding the addition of zinc forms or doses and their relation to the immune response and production performance of broilers. Different doses or forms of zinc were identified in the database. The recorded parameters were related to the immune response and production performance. The database contained a total of 323 data points from 41 studies that met the criteria. Then, the data were processed for a meta-analysis using a mixed model methodology. The doses or different forms of zinc were considered fixed effects, different studies were treated as random effects, and p-values were used as the model statistics.

Results

An increase in zinc dose increased (p<0.05) pancreas metallothionein (MT) and zinc concentrations in the plasma, tibia and meat, all in quadratic patterns, but linearly decreased (p<0.05) the heterophil/lymphocyte (H/L) ratio. Regarding the different zinc forms, both inorganic and organic zinc increased (p<0.05) the zinc concentrations in the plasma and tibia, the calcium and phosphorus contents in the tibia, and the antioxidant activity of superoxide dismutase in meat as compared to control. An increase in zinc dose increased average daily gain (ADG) and decreased feed conversion ratio (FCR) following a quadratic pattern (p<0.05). Inorganic and organic zinc decreased (p<0.05) FCR and H/L ratio than that of control, but these two forms were similar for these parameters.

Conclusion

Zinc addition has a positive impact on immunity and broiler production. Zinc can suppress stress and inhibit the occurrence of lipid peroxidation in broilers, and it can also improve ADG, FCR, and the quality of broiler carcasses.

Effects of ZnO addition on thermal properties, degradation and biocompatibility of P45Mg24Ca16Na(15−x)Znx glasses

Four phosphate-based glass formulations in the system P45Mg24Ca16Na(15−x)Znx, referred to as P45Znx (x = 0, 5, 10 and 15 mol%), were prepared using a melt quenching process. The effect of ZnO addition on density, molar volume, thermal properties and degradation rates were studied. An increase in the glass transition, crystallisation, melting and liquidus temperatures were seen when replacing Na2O with ZnO. The molar volume of the bulk glasses was seen to decrease with increasing ZnO content. The dissolution rate of the zinc-free glass was 2.48 × 10−8 kg m−2 s−1 and addition of 5 mol% ZnO resulted in a reduction of the dissolution rate to 1.68 × 10−8 kg m−2 s−1. However, further addition of ZnO from 5 mol% to 15 mol% increased the dissolution rate of the glass system. The glasses were deliberately crystallised and XRD studies identified the Z n2P2O7 phase for glass code P45Zn5, and Zn(PO3)2 phase for P45Zn10 and P45Zn15 glasses. Cyto-compatibility studies were conducted using MG63 cells for 14 days. An overall increase in the metabolic activity and DNA concentration of cells was seen from day 1 to day 14 for all glass formulations investigated. However, increasing ZnO content from 0 to 15 mol% seemed to have a negative effect on the cellular activity. Interestingly, a remarkably higher ALP activity was seen at day 14 for glass codes P45Zn5 and P45Zn10 in comparison with the TCP control and the P45Zn0 glass.

Effect of zinc concentration and source on performance, tissue mineral status, activity of superoxide dismutase enzyme and lipid peroxidation of meat in broiler chickens

The present experiment was conducted to investigate the effect of feeding different concentrations and the source of zinc (Zn) on the performance, tissue mineral status, superoxide dismutase (SOD) enzyme activity and meat quality in 0–4-week-old broiler chicks. Dietary treatments included the corn–soybean meal-based diet (control) and the basal diet supplemented with Zn at 20, 50 or 80 mg/kg, added as ZnSO4, Zn-methionine or Zn-enriched yeast. The results showed that birds fed Zn-supplemented diets had higher average weight gain and average feed intake than did birds fed the control diet (P < 0.01). At the end of the experiment, the Zn deposition in pancreas, liver and tibia increased (P < 0.01), regardless of the source, in response to increasing dietary Zn concentrations, whereas plasma Zn status was significantly increased by the highest Zn supplementation level. The main effect of Zn supplementation level was significant for the activities of Cu and/or Zn SOD in the liver and pancreas (P < 0.01). As broiler given 50 mg Zn had higher tissue SOD activity than did broilers fed the other treatment diets. Furthermore, Zn supplementation at up to 50 mg/kg significantly increased (P < 0.01) Zn accumulation and SOD activity and decreased lipid peroxidation in muscles around the femur bone. Results from the present study demonstrated that supplementation with 50 mg Zn may be sufficient for normal broiler growth to 28 days of age and the dietary inclusion of organic Zn could be utilised more effectively than that of inorganic sources.

The Content of Structural and Trace Elements in the Knee Joint Tissues

Many elements are responsible for the balance in bone tissue, including those which constitute a substantial proportion of bone mass, i.e., calcium, phosphorus and magnesium, as well as minor elements such as strontium. In addition, toxic elements acquired via occupational and environmental exposure, e.g., Pb, are included in the basic bone tissue composition. The study objective was to determine the content of strontium, lead, calcium, phosphorus, sodium and magnesium in chosen components of the knee joint, i.e., tibia, femur and meniscus. The levels of Sr, Pb, Ca, P, Na and Mg were the highest in the tibia in both men and women, whereas the lowest in the meniscus. It should be noted that the levels of these elements were by far higher in the tibia and femur as compared to the meniscus. In the components of the knee joint, the level of strontium showed the greatest variation. Significant statistical differences were found between men and women only in the content of lead.

Antibacterial properties of poly (octanediol citrate)/gallium-containing bioglass composite scaffolds

Bioactive glasses may function as antimicrobial delivery systems through the incorporation and subsequent release of therapeutic ions. The aim of this study was to evaluate the antimicrobial properties of a series of composite scaffolds composed of poly(octanediol citrate) with increased loads of a bioactive glass that releases zinc (Zn(2+)) and gallium (Ga(3+)) ions in a controlled manner. The antibacterial activity of these scaffolds was investigated against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. The ability of the scaffolds to release ions and the subsequent ingress of these ions into hard tissue was evaluated using a bovine bone model. Scaffolds containing bioactive glass exhibited antibacterial activity and this increased in vitro with higher bioactive glass loads; viable cells decreased to about 20 % for the composite scaffold containing 30 % bioactive glass. The Ga(3+) release rate increased as a function of time and Zn(2+) was shown to incorporate into the surrounding bone.

Characterizing the composition of bone formed during fracture healing using scanning electron microscopy techniques

About 5-10% of all bone fractures suffer from delayed healing, which may lead to non-union. Bone morphogenetic proteins (BMPs) can be used to induce differentiation of osteoblasts and enhance the formation of the bony callus, and bisphosphonates help to retain the newly formed callus. The aim of this study was to investigate if scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) can identify differences in the mineral composition of the newly formed bone compared to cortical bone from a non-fractured control. Moreover, we investigate whether the use of BMPs and bisphosphonates-alone or combined-may have an effect on bone mineralization and composition. Twelve male Sprague-Dawley rats at 9 weeks of age were randomly divided into four groups and treated with (A) saline, (B) BMP-7, (C) bisphosphonates (Zoledronate), and (D) BMP-7 + Zoledronate. The rats were sacrificed after 6 weeks. All samples were imaged using SEM and chemically analyzed with EDS to quantify the amount of C, N, Ca, P, O, Na, and Mg. The Ca/P ratio was the primary outcome. In the fractured samples, two areas of interest were chosen for chemical analysis with EDS: the callus and the cortical bone. In the non-fractured samples, only the cortex was analyzed. Our results showed that the element composition varied to a small extent between the callus and the cortical bone in the fractured bones. However, the Ca/P ratio did not differ significantly, suggesting that the mineralization at all sites is similar 6 weeks post-fracture in this rat model.

Chemical elements of human bone tissue investigated by nuclear analytical and related methods

The mass fractions (in milligrams per kilogram given on a dry mass basis) of 69 chemical elements in the intact rib bone of 84 apparently healthy 15- to 58-year-old citizens (38 females and 46 males) of a nonindustrial region were investigated using five instrumental analytical methods: neutron activation analysis with high-resolution spectrometry of short- and of long-lived radionuclides, particle-induced gamma-ray emission spectrometry, inductively coupled plasma atomic emission, and mass spectrometry. The mass fractions of chemical elements were measured for rib bone of both males and females, taken separately and together. The present results indicate that rib bone can be used as exposure monitors in occupational medicine and environmental health studies to assess, or indicate, the body burden of Al, B, Ba, Be, Ca, Cr, F, Li, Mg, Na, Ni, P, Pb, rare-earth elements (REEs), Sr, and Zn. Our data show an exponential increase with the age of the content of REEs in the rib of people living in an ecologically safe region.

Data for the Reference Man: skeleton content of chemical elements

This study was undertaken to provide reference values of chemical element mass fractions in intact bone of Reference (European Caucasian) Man/Woman. The rib bone samples investigated were obtained from autopsies of 84 apparently healthy 15-58-year-old citizens (38 females and 46 males) of a non-industrial region in the Central European part of Russia who had suffered sudden death. The mass fractions (mg/kg given on a wet mass basis) of 69 elements in these bone samples were measured by using neutron activation analysis with high-resolution spectrometry of short-lived and long-lived radionuclides, particle-induced gamma-ray emission, inductively coupled plasma atomic emission spectrometry, and inductively coupled plasma mass spectrometry including necessary quality control measures. Using published and measured data, mass fraction values of the 79 elements for the rib bone have been derived. Based on accepted rib to skeleton mass fractions and reference values of skeleton mass for Reference Man, the elemental burdens in the skeleton were estimated. These results may provide a representative bases for establishing related reference values for the Russian Reference Man/Woman and for revising and adding current reference values for the International Commission on Radiological Protection. The data presented will also be very valuable for many other applications in radiation protection, radiotherapy radiation dosimetry, and other scientific fields.

The effect of age and gender on 59 trace-element contents in human rib bone investigated by inductively coupled plasma mass spectrometry

The effect of age and gender on 59 trace-element contents in rib bone of 80 apparently healthy 15-55-year-old women (n = 38) and men (n = 42) was investigated by inductively coupled plasma mass spectrometry. Mean values (M ± SΕΜ) for the mass fraction (milligrams per kilogram, on dry-weight basis) of Ba, Bi, Cd, Ce, Cu, Dy, Er, Gd, La, Li, Mn, Mo, Nd, Pb, Pr, Rb, Sm, Sr, Tb, Tl, U, Yb, and Zn for both female and male taken together were: Ba 2.5 ± 0.2, Bi 0.015 ± 0.002, Cd 0.044 ± 0.005, Ce 0.029 ± 0.002, Cu 1.05 ± 0.06, Dy 0.0020 ± 0.0003, Er 0.0011 ± 0.0002, Gd 0.0015 ± 0.0001, La 0.020 ± 0.002, Li 0.040 ± 0.002, Mn 0.354 ± 0.004, Mo 0.052 ± 0.006, Nd 0.011 ± 0.001, Pb 2.24 ± 0.14, Pr 0.0032 ± 0.0004, Rb 1.51 ± 0.06, Sm 0.0014 ± 0.0001, Sr 291 ± 20, Tb 0.00041 ± 0.00005, Tl 0.00050 ± 0.00003, U 0.0013 ± 0.0001, Yb 0.00072 ± 0.00007, and Zn 92.8 ± 1.5, respectively. The upper limit of mean contents of Ag, Al, B, Be, Br, Cr, Cs, Hg, Ho, Lu, Ni, Sb, Te, Th, Ti, Tm, and Y were: Ag ≤ 0.011, Al ≤ 7.2, B ≤ 0.65, Be ≤ 0.0032, Br ≤ 3.9, Cr ≤ 0.25, Cs ≤ 0.0077, Hg ≤ 0.018, Ho ≤ 0.00053, Lu ≤ 0.00024, Ni ≤ 1.05, Sb ≤ 0.0096, Te ≤ 0.0057, Th ≤ 0.0030, Ti ≤ 2.8, Tm ≤ 0.00006, and Y ≤ 0.0047, respectively. In all bone samples, the contents of As, Au, Co, Eu, Ga, Hf, Ir, Nb, Pd, Pt, Re, Rh, Sc, Se, Sn, Ta, V, W, and Zr were under detection limits. The Ce, Dy, Er, Gd, La, Nd, Pr, Sm, Tb, and Yb contents increase with age. Higher Sr mass fraction is typical of female rib as compared to those in male bone.

The effect of age and gender on 38 chemical element contents in human femoral neck investigated by instrumental neutron activation analysis

The effect of age and gender on 38 chemical element contents in femoral neck of 85 apparently healthy 15-55-year-old women (n = 38) and men (n = 47) was investigated by instrumental neutron activation analysis. Mean values (M +/- SEpsilonMu) for mass fraction (on dry weight basis) of Ca, Cl, Co, Fe, K, Mg, Mn, Na, P, Sr, and Zn for both female and male taken together were: Ca 153 +/- 3 g/kg, Cl 1,188 +/- 48 mg/kg, Co 0.0039 +/- 0.0004 mg/kg, Fe 55.5 +/- 8.8 mg/kg, K 490 +/- 22 mg/kg, Mg 1,940 +/- 48 mg/kg, Mn 0.385 +/- 0.015 mg/kg, Na 3,850 +/- 70 mg/kg, P 73.0 +/- 1.5 g/kg, Sr 288 +/- 18 mg/kg, and Zn 55.5 +/- 1.6 mg/kg, respectively. The upper limit of mean contents of Cr, Cs, Eu, Hg, Rb, Sb, Sc, and Se were: Cr < or = 0.2, Cs < or = 0.02, Eu < or = 0.007, Hg < or = 0.006, Rb < or = 0.8, Sb < or = 0.02, Sc < or = 0.0004, and Se < or = 0.06 mg/kg, respectively. In all bone samples, the contents of Ag, As, Au, Ba, Br, Cd, Ce, Gd, Hf, La, Lu, Nd, Sm, Ta, Tb, Th, U, Yb, and Zr were under detection limits. The Ca, Mg, and P contents decrease with age. Higher Ca, Cl, K, Mg, Mn, Na, and Sr mass fractions are typical of female femoral neck as compared to those in male bone.

The effect of age and gender on 38 chemical element contents in human iliac crest investigated by instrumental neutron activation analysis

PROJECT

To understand the role of major, minor, and trace elements in the etiology of bone diseases including osteoporosis, it is necessary to determine the normal levels and age-related changes of bone chemical elements.

PROCEDURE

The effect of age and gender on 38 chemical element contents in intact iliac crest of 84 apparently healthy 15-55 years old women (n=38) and men (n=46) was investigated by neutron activation analysis.

RESULTS

Mean values (M+/-SEM) for mass fraction (on dry weight basis) of Ca, Cl, Co, Fe, K, Mg, Mn, Na, P, Rb, Sr, and Zn for both female and male taken together were Ca - 169+/-3g/kg, Cl - 1490+/-43 mg/kg, Co - 0.0073+/-0.0024 mg/kg, Fe - 177+/-24 mg/kg, K - 1820+/-79 mg/kg, Mg - 1840+/-48 mg/kg, Mn - 0.316+/-0.013 mg/kg, Na - 4970+/-87 mg/kg, P - 79.7+/-1.5 g/kg, Rb - 1.89+/-0.22 mg/kg, Sr - 312+/-15 mg/kg, and Zn - 65.9+/-3.4 mg/kg, respectively. The upper limit of mean contents of Cs, Eu, Hg, Sb, Sc, and Se were Cs < or = 0.09 mg/kg, Eu < or = 0.005 mg/kg, Hg < or = 0.005 mg/kg, Sb < or = 0.004 mg/kg, Sc < or = 0.001 mg/kg, and Se < or = 0.1mg/kg, respectively. In all bone samples the contents of Ag, As, Au, Ba, Br, Cd, Ce, Cr, Gd, Hf, La, Lu, Nd, Sm, Ta, Tb, Th, U, Yb, and Zr were under detection limits.

CONCLUSIONS

The Ca, Mg, and P contents decrease with age, regardless of gender. Higher Ca, Mg, P, and Sr mass fractions as well as lower Fe content are typical of female iliac crest as compared to those in male bone.

The effect of age and gender on Al, B, Ba, Ca, Cu, Fe, K, Li, Mg, Mn, Na, P, S, Sr, V, and Zn contents in rib bone of healthy humans

The effect of age and gender on major, minor, and trace element contents in the intact rib bone of 80 relatively healthy 15-55-year-old women and men was investigated. Contents or upper limit of contents of 16 chemical elements in the rib bone were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). Mean values (M +/- SEpsilonMu) for the mass fraction of Ba, Ca, Cu, Fe, K, Li, Mg, Na, P, S, Sr, and Zn (milligram per kilogram of dry bone) were as follows: 2.54 +/- 0.16, 171,400 +/- 4,050, 1.35 +/- 0.22, 140 +/- 11, 1,874 +/- 71, 0.049 +/- 0.011, 2,139 +/- 38, 5,378 +/- 88, 75,140 +/- 1,660, 1,881 +/- 51, 291 +/- 20, and 92.8 +/- 1.5, respectively. The upper limits of contents of Al, B, Mn, and V were <7.20, <0.65, <0.36, and <0.03, respectively. Statistically significant tendency for the Ca, Mg, and P content to decrease with age was found in the human rib bone, regardless of gender. The mass fraction of Fe in the male rib bone increases with age. It was shown that higher Ca, Mg, Na, P, and Sr mass fractions as well as lower Fe content were typical of female ribs as compared to those in male ribs.

On the possibilities of ICP-AES for analysis of archaeological bones

The possibility of using inductively coupled plasma atomic emission spectrometry (ICP-AES) to determine the elemental composition of archaeological bones elements was evaluated and discussed. The interferences of the major elements (Ca, P, K, Na, Al and Fe) on the microelements (Ba, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sr, Zn) were investigated and the appropriate analytical lines were selected. The role of different nebulizers (cross-flow, Babington and Meinhard) on detection limits were investigated. The applicability of the proposed procedure was demonstrated analyzing IAEA-SRM-H-5 (Animal bone); and authentic bone sample dating back to the 4th century BC. These results were compared to ETAAS and ICP-MS.

Calcium and phosphorus concentrations and the calcium/phosphorus ratio in trabecular bone from the femoral neck of healthy humans as determined by neutron activation analysis

The Ca and P concentrations as well as the Ca/P ratio were estimated in intact trabecular bone samples from the femoral neck of healthy humans, 34 women and 44 men, aged from 15 to 55 years, using instrumental neutron activation analysis. The mean values (M+/-SD) for the investigated parameters (on a dry-weight basis) were: 12.1+/-3.0%, 5.94+/-1.71%, 2.07+/-0.25 and 10.9+/-2.5%, 5.30+/-1.23%, 2.07+/-0.22 for females and males, respectively. A statistically significant (p</=0.05) decrease of Ca concentration with age was found only for males while the P concentration and the Ca/P ratio were not affected by age. No statistically significant sex-related differences were observed in any of the parameters. The mean values for Ca, P and the Ca/P ratio lay close to the median of the very wide range of published data. The individual variation for the Ca/P ratio in trabecular bone from the healthy human femoral neck was lower than those for Ca and P separately. This suggests that the specificity of the Ca/P ratio is better than that of Ca and P concentrations and may be more reliable for the diagnosis of bone disorders.

Neutron activation analysis of calcium/phosphorus ratio in rib bone of healthy humans

The Ca/P ratio was estimated in intact rib bone samples from healthy humans, 37 women and 45 men, aged from 15 to 55 years using instrumental neutron activation analysis. No statistically significant differences (p>0.05) age- or sex-related differences in the Ca/P ratio were observed. The mean value (M+/-SD) for the investigated parameter for the whole group studied, 2.33+/-0.34, was within a very wide range of published data and close to the median value.

Determination of calcium, phosphorus, and the calcium/phosphorus ratio in cortical bone from the human femoral neck by neutron activation analysis

Concentrations of Ca and P as well as the Ca/P ratio were estimated in intact cortical bone samples from the femoral neck of healthy humans, 33 women and 45 men, aged from 15 to 55 yr using instrumental neutron activation analysis. Mean values (M +/- SD) for the investigated parameters (on dry weight basis) were: 23.0 +/- 3.9%, 10.7 +/- 2.4% and 2.17 +/- 0.31, respectively. No statistically significant differences of the above parameters were observed related either to age or sex. The mean values for Ca, P and Ca/P ratio were within a very wide range of published data and close to their median. The individual variation for the Ca/P ratio in cortical bone from the healthy human femoral neck was lower than those for Ca and P separately. This means that specificity of Ca/P ratio is better than those of Ca and P concentrations are and may be more reliable for diagnosis of bone disorders.

Reduced growth and skeletal changes in zinc-deficient growing rats are due to impaired growth plate activity and inanition

We investigated the effects of dietary zinc deficiency on skeletal metabolism in an animal model. Thirty 21-d-old male Sprague-Dawley rats were fed for 28 d either a zinc-deficient (ZD) diet (1 mg zinc/kg) or a normal diet ad libitum (AL, 50 mg zinc/kg) or in the same quantity as the ZD (pair-fed, PF). Only in the ZD group were general physical signs of zinc deficiency observed. Compared with the AL and PF rats, ZD rats showed significantly lower mean values in ponderal growth rate, femur weight and length, circulating levels of insulin-like growth factor-I, bone mechanical properties and concentration of zinc and, on histomorphometry, a decrease in the thicknesses of the overall growth plate and hypertrophic cartilage. In contrast, although bone volume was significantly lower in the ZD and PF rats than in the AL rats, no difference was observed between the ZD and PF rats. Osteoclast surface/bone surface and osteoclast number/bone surface ratios were significantly greater in PF rats than in the other two groups and not different in ZD and AL rats. Collectively, these data indicate that zinc deficiency has profound effects on the skeletal system of growing rats. In particular, the effects of zinc deficiency on bone growth and mass are the result of the reduced activity of the growth plate, likely mediated by impairment in the insulin-like growth factor-I system. We did not demonstrate an effect on bone mass via increased bone resorption.

Perturbations in factors that modulate osteoblast functions in vitamin B6 deficiency

It was hypothesized that the widespread structural defect of collagen in connective tissue of vitamin B6deficient-animals and the consequent alteration in bone biomechanical properties cause an additional stress to their inflammed swollen tibiotarsometatarsal joints. The present study showed a 32% elevation (P &lt 0.02) in mean plasma free cortisol concentration. Vitamin D metabolism was impaired but without changing plasma calcium homeostasis and bone mineral content. Mean plasma calcitriol [1,25(OH)2D] concentration was significantly reduced (P < 0.001). Because plasma calcidiol concentration did not change, we speculated that either renal 25-hydroxycalciferol-1α-hydroxylase activity was reduced or 1,25(OH)2D turnover was increased. Plasma osteocalcin, an index of osteoblast function related to bone formation, was significantly decreased (P < 0.05). This adverse effect on osteoblasts was consistent with the reduction of bone specific alkaline phosphatase activity (another index of bone formation) found in a previous study. The excess of cortisol may have impaired these bone cells functions directly and (or) indirectly via the decline in calcitriol synthesis. Plasma hydroxyproline concentrations in B6-deficient animals were found to be significantly reduced (P < 0.001), suggesting that cortisol in excess had also a suppressive effect on another hydroxylase, namely tissue (mainly bone and liver) prolyl hydroxylase. The bone uncoupling (in formation and resoption) associated with vitamin B6deficiency seems to be due to secondary hypercortisolism and (or) another unknown factors but not related to a change in bone modulators such as IGF-1 and eicosanoids.Key words: collagen, vitamin B6, vitamin D, cortisol, osteocalcin, IGF-1, eicosanoids, PGE2.

Structure, composition, and maturation of newly deposited calcium-phosphate crystals in chicken osteoblast cell cultures

Characterization of the very early calcium phosphate (CaP) crystals deposited in bone or in osteoblast cell cultures has been hampered by the overwhelming presence of organic matrix components and cells that obscure spectral analyses. We have overcome this problem using isolated protein-free crystals and have obtained new data including 31P nuclear magnetic resonance (NMR) spectra for the first time from mineral crystals deposited during osteoblast calcification in culture. Crystals were isolated from cultures at two time points: (a) at first calcium accumulation (day 8-10) and (b) after 60 days of culture, to assess maturational changes. The analyses show that the chemical composition overall and short range order of the early and mature crystals are characteristic of the apatite crystals found in young embryonic chick bone in vivo. No mineral phase other than apatite was detected by any of the methods used. 31P NMR spectroscopy identified the HPO4 groups as those present in bone apatite. Similar to bone apatites, no OH groups were detected by Fourier transform infrared (FTIR) spectroscopy. The temporal maturational changes in composition and structure of the mineral phase were difficult to assess because of the continuous deposition of crystals throughout culturing. The pathway of the maturational changes observed were similar to those occurring in chick bone in vivo and synthetic apatite crystals in vitro although to a much smaller extent.

Zinc mapping in bone tissues by histochemistry and synchrotron radiation-induced X-ray emission: correlation with the distribution of alkaline phosphatase

Zinc distribution in osteons was mapped by synchrotron radiation-induced X-ray emission analysis in both human and porcine adult bone, as well as in porcine bone by histochemistry using Timm's method. Both procedures showed that zinc is not uniformly distributed, being in its highest concentration on haversian bone surfaces. When Timm's method was applied in conjunction with a procedure leading to partial zinc extraction, three zinc pools were specifically detected: a loose one, found in the mineralizable osteoid; a mineral one, bound to the bone mineral; and a tenacious one, firmly bound to an organic component located in the osteoid and mineralizing organic matrix. The alkaline phosphatase distribution was also mapped in porcine adult bone by histochemistry and immunohistochemistry and it was found codistributed with tenacious zinc mainly at the calcification front. The data suggest that alkaline phosphatase is buried as a bone matrix protein during initial mineralization.

Age-independent constancy of mineral contents in human ribs

On age relationships of mineral contents in human bones, the contents of the sixth rib and a piece of its compact bone were determined by inductively coupled plasma atomic emission spectrometry (ICPS). The ribs were resected from 21 subjects (14 men and 7 women) who died in age ranging from 65 to 93 yr. There were no age-dependent decreases in Ca and P contents of the ribs in the age range on ICPS. It was found that there were no age-dependent decreases in Ca and P in compact bones of ribs.

Age-independent constancy of mineral contents in human vertebra and auditory ossicle

To elucidate age-related changes of mineral contents in human bones, element contents of human vertebrae and auditory ossicles were determined by inductively coupled plasma atomic-emission spectrometry. The cervical, thoracic, and lumbar vertebrae were removed from 12 vertebral columns. The mallei of auditory ossicle were removed from 27 cadavers. It was found that average relative contents (RCs) of calcium and phosphorus in cervical, thoracic, and lumbar vertebrae remained almost constant within ages ranging from 46 to 99 y. In addition, it was found that the RCs of calcium and phosphorus in men's and women's mallei remained constant within ages ranging from 40 to 98 yr. These results support the view that there is no significant age-dependent change of mineral contents in human bones.

Osteoblast-mediated effects of zinc on isolated rat osteoclasts: inhibition of bone resorption and enhancement of osteoclast number

Zinc is an important element in biology yet little is understood of its role in bone cell metabolism and function. This study examined the effects of zinc on osteoclast (OC) function in cultures derived from neonatal rats and in cocultures of OC and UMR 106-01 osteoblast-like cells (UMR/OC cocultures). Treatment with zinc (10(-12)-10(-4) mol/L) had no effect on either bone resorption or the number of multinucleate cells positive for tartrate-resistant acid phosphatase (TRACP + ve MNC) in OC cultured for 24 h on bone slices. However, in UMR/OC cocultures, 10(-4) mol/L zinc (but not lower concentrations) decreased resorption pit formation by approximately 50% and increased TRACP + ve MNC number by approximately 40%. When osteoblast-like cells were pretreated with zinc prior to, but not during, coculture with OC, effects on TRACP + ve MNC and pit number persisted, although the effect was reduced. Zinc treatment also inhibited resorption and stimulated TRACP and calcitonin receptor (CTR) + ve MNC numbers in long-term (96-120 h) UMR/OC cocultures. Our results indicate that zinc increases TRACP + ve CTR + ve MNC numbers yet inhibits bone-resorbing activity, and that these effects are dependent on the presence of osteoblastic cells. Zinc is abundant in bone and may act as a local regulator of bone cells.

Difference of mineral contents in human intervertebral disks and its age-related change

To establish a difference of the relative contents (RCs) of elements among the cervical, thoracic, and lumbar intervertebral disks and its age-related change, the intervertebral disks between the axis and the sacrum, which were resected from the nine cadavers who died at 53 to 99 yr old, were analyzed by inductively coupled atomic plasma emission spectrometry. It was found that both the RCs of calcium and phosphorus were high in the cervical disks, especially the highest in the disk between the 6th and 7th cervical vertebrae, and lower in the order of the cervical, thoracic, and lumbar intervertebral disks. In regard to the RCs of sulfur and magnesium, there were no significant differences among the cervical, thoracic, and lumbar intervertebral disks. In addition, it was found that both the RCs of calcium and phosphorus in the cervical intervertebral disks started to increase in the sixth decade of life, became the highest in the eighth decade of life, and then decreased.

Strontium increases vertebral bone volume in rats at a low dose that does not induce detectable mineralization defect

Low doses of strontium and fluoride were shown to increase bone formation and trabecular bone density in rodents. To assess whether strontium or fluoride affect the quality of the mineral at doses known to increase bone density, we have determined the effects of low doses of strontium and fluoride on bone formation and bone mineral characteristics in rats. Adult rats were given strontium alone (0.20%), fluoride alone (1 mg/kg per day), or the combined treatment for 8 weeks. Strontium levels in serum and femur were similar in groups treated with strontium alone or in combination, being about 5% of calcium levels. Biochemical and neutron activation analyses in femur showed that calcium and magnesium contents did not differ in the four group of rats, suggesting that strontium was incorporated in the apatite lattice of the bone minerals in the strontium-treated rats. The mineralized bone volume was significantly increased by 17% in the strontium-treated group, by 20% in the fluoride-treated group, and by 19% in rats given with the combined treatment. This was associated with increased osteoid surface, osteoblast surface, and double tetracycline labeled surfaces in the strontium-treated and fluoride-treated groups, showing that the number of bone forming sites was increased. However, the mineral apposition rate, the osteoid thickness, and the mineralization lag time were similar in controls and treated groups, reflecting the lack of deleterious effects of low doses of strontium and fluoride on bone mineralization. The density fractionation analysis measured in the femur also showed that neither strontium, nor fluoride at the low doses used, significantly altered the mineralization profile. The results indicate that treatment with low doses of strontium or fluoride increase the number of bone forming sites and vertebral bone volume in rats, but does not have detectable adverse effects on the mineral profile, bone mineral chemistry or bone matrix mineralization.

Elemental analysis of femoral bone from patients with fractured neck of femur or osteoarthrosis

The elemental composition of bone has been determined by inductively coupled atomic emission and mass spectrometry to test the hypothesis that changes in major or minor elemental concentrations may contribute to the risk of fracture. Femoral bone was obtained from patients at operation for the treatment of fracture and compared with that of patients with osteoarthrosis and a necropsy control group. The data suggest that there are no major differences in bone elemental composition in patients with fractures compared with the control group. Bone adjacent to joints with osteoarthrosis tends to be less mineralized (per unit trabecular bone volume) than control bone and bone from fracture patients, and has significantly lower concentrations of boron, lead and, zinc. These observations may reflect the more rapid turnover of bone close to the arthritic joint.

Zinc is a potent inhibitor of osteoclastic bone resorption in vitro

It is well established that zinc, an essential trace element, plays an important role in growth and stimulates bone formation. However, the effects of zinc on bone resorption have received little attention. We studied its effects on isolated rat osteoclasts. Unexpectedly, osteoclasts were exquisitely sensitive to zinc, with a significant decrease in bone resorption occurring at concentrations as low as 10(-14) M. This effect was specific for zinc and was not observed with the other transitional or alkaline metals studied. There was no evidence of toxicity at concentrations up to 10(-4) M. Zinc also completely abolished the stimulatory effect of parathyroid hormone. Zinc is therefore a highly potent and selective inhibitor of osteoclastic bone resorption in vitro. The mode of action remains to be established and may represent a novel inhibitory mechanism in the osteoclast.

Energy-dispersive X-ray microanalysis of the bone mineral content in human trabecular bone: a comparison with ICPES and neutron activation analysis

To evaluate the accuracy of bone mineral composition determination by electron microprobe analysis (EDX) the measurements have been compared to instrumental neutron activation analysis (INAA) and chemical analysis (ICPES). Bone specimens from five femoral heads were used. The trabecular content of calcium (Ca) and phosphorus (P) was analyzed by the three different methods. The EDX method allows for a microstructural analysis of intact, methylmetacrylate-embedded, undecalcified bone and the measuring points can thus be distinctly identified centrally in each trabecula. The analysis yielded 25.8 +/- 0.7 wt % Ca and 10.5 +/- 0.1 wt % P, compared with 22.2 +/- 0.5 and 23.0 +/- 1.0 wt % Ca, and 9.83 +/- 0.21 and 10.02 +/- 0.44 wt % P for INAA and ICPES, respectively. The EDX analysis was calibrated by consecutive measurements of a hard, pressed tablet of hydroxyapatit of known content. The mean Ca content deviated with -0.38 wt % from the given content and P with -0.89 wt %. We could not verify any particular interference from the embedding procedure, however, it is possible that the relatively lower P content still may reflect this. The magnesium (Mg) concentration was 0.31 +/- 0.02 wt % by EDX and 0.26 +/- 0.02 wt % by INAA. The EDX analytical method provides a useful tool for simultaneous elemental quantification in bone. It has the advantage of permitting the use of regular bone biopsy material and thus allowing for a unique microstructural evaluation of the degree of mineralization.(ABSTRACT TRUNCATED AT 250 WORDS)

The development of a technique to measure bone aluminium content using neutron activation analysis

The accumulation and toxicity of aluminium in patients with chronic renal failure is a well recognized hazard, and there is a need for a non-invasive technique to assess Al tissue load in these patients. The technique of in vivo neutron activation analysis, using a thermal neutron beam from a reactor, has been employed by previous workers, who measured Al in the hand with a detection limit of 0.4 mg for a dose equivalent of 20 mSv. However, the application of this technique is restricted by the very limited availability of nuclear reactors. We report the modification of an existing 252Cf-based instrument and construction of a shielded, high-efficiency counting system for the in vivo measurement of Al in the hand. Phantoms containing tissue-equivalent solutions of Ca, P, Na and Cl with various Al loadings were used for validation of the technique. The Al/Ca ratio in the hands of seven patients with renal failure was measured using a cyclic activation technique to compensate for the relatively low neutron output of the 252Cf source, and a detection limit of approximately 2.2 mg Al was achieved for a dose equivalent of 36 mSv. The results were compared with the Al content of iliac crest bone biopsy specimens measured using electrothermal atomic absorption spectrophotometry.

The effects of diet, age, and sex on the mineral content of primate bones

The effect of diet, age, and sex on the mineral content of primate bones was determined for free-ranging rhesus monkeys (Macaca mulatta) from the Caribbean Primate Research Center. Monkeys in this study were of known age and sex and had been provided with either a low protein (15%) or a high protein (25%) diet for most of their lives. Instrumental neutron activation analysis was used to assess bone mineral content. Results showed that diet had no significant effect on the bulk mineral composition of Ca, Mg, Br, and Cl in the bones. Of the minerals analyzed, only Na and Mn showed significant diet-related effects. The bone Ca content was found to be lower in females than in males when controlled for age. Finally, Ca content was found to be higher in young adults, lower at middle age, and higher in old age in both male and female monkeys. In conclusion, this study has shown that increasing protein content in the diet does not change the bulk mineral content of primate bones. The nondietary effect that Ca content of monkey bones is lower during middle age has not been previously reported.

The effect of fluoride treatment on bone mineral crystals in the rat

In order to investigate the effect of fluoride on bone mineral crystals, we gave groups of female rats 8 mM NaF/L water and distilled water to control groups. The rats were sacrificed at six weeks, three months, and six months. The fluor content of the bone was determined by neutron activation. X-ray diffraction showed no difference in bone crystal size/strain with fluoride treatment. Fourier transform Infrared Spectroscopy (FTIR) showed an increased crystallinity in fluoride-fed animals, which seems to be associated with a decrease of labile phosphate environment. Three carbonate bands have been found in fluoridated and normal bone samples. The distribution of carbonate ions on type A and B sites is strongly affected by fluoride. Type A carbonate is always present in bone, but decreases with increasing bone fluoride content. A carbonate band found at 866 cm-1 may correspond to a fluoride interaction with type B carbonate ions. Lastly, phosphate bands have been found to be shifted towards high wave number, which is probably related to the change in unit cell size induced by the fluoride ion. All these changes induced by fluoride reduce the solubility of bone crystals by direct incorporation of fluoride ions in the apatite lattice and by decreasing the labile phosphate environments.

Effects of fluoride on rat cancellous bone

Female Wistar rats were divided into four groups each fed ad libitum regular rodent chow and fluoridated water at four levels (0, 2, 4, 6 mmol/l) for 3 months. There were significant differences in ash weights between control and fluoridated vertebrae (P less than 0.01). Intact bone fluoride (F) values observed were: 0.04 +/- 0.01% fat-free dry weight (ffdw) for control vertebrae and 0.22-0.34 +/- 0.03% ffdw for fluoridated vertebrae. Deproteinized fluoridated vertebral bone had significantly lower specific surface area (SSA) (from 100 +/- 19 m2/g, P less than 0.01, down to 80 +/- 20 m2/g, P less than 0.001) than the control group (120 +/- 10 m2/g); a finding in support of our hypothesis that more of the bone mineral units in fluoridated bone are older (hence denser) than in normal bone. Static morphometric analysis of toluidine blue-stained sections of the femoral metaphyses showed that both cancellous bone volume/tissue volume (Cn-BV/TV) and trabecular thickness (Tb.Th) increased linearly with NaF dosage (R = 0.99 and 0.97, respectively); with Cn-BV/TV increasing from 21 +/- 7 to 33 +/- 6% (P less than 0.01) and Tb.Th from 76 +/- 8 to 98 +/- 9 microns (P less than 0.01). Similar Cn-BV/TV results were also obtained from von Kossa-stained sections.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of dry ashing on the composition of human and animal bone

Elemental analysis of archaeological bones, particularly for elements such as fluorine, strontium, and zinc, has been carried out for many years, with the aim of determining their age or relating their composition to diet. Bone samples are commonly dry ashed before analysis to remove organic material and render them more readily soluble. In this study, the recoveries of strontium, zinc, and nine other elements are reported for a range of ashing times and temperatures. Recoveries of sodium, potassium, fluorine, chlorine, bromine, and zinc are significantly affected by ashing under some conditions, but recoveries of strontium, calcium, magnesium, and manganese are not.

Concentration of bone elements in osteoporosis

In aging and in osteoporosis, decreased bone density is associated with decreased bone mass. However, changes in the bone mineral phase remain a matter for investigation. In particular, it is unknown whether bone mineral loss is directly related to reduction in bone mass or associated with changes in the concentration of mineral elements in mineralized bone tissue. In this study, the cortical bone concentration of elements was determined in biopsies of the ilium from 33 subjects (12 controls and 21 individuals with untreated severe osteoporosis). Calcium and phosphorus concentrations were evaluated in cortical and trabecular bone using energy-dispersive x-ray (EDX) microanalysis and inductively coupled plasma optical emission spectrometry (ICPOES). Bone concentrations of Na, K, Mg, Cu, Zn, Fe, Sr, Al, B, and Si were also determined in cortical bone using ICPOES. Additionally, the concentration of F in cortical bone was measured with a specific ion electrode and the concentration of Pb was determined by atomic absorption spectrometry. In mineralized bone tissue there was no significant age-dependent variation in the concentration of Ca, P, or other elements either in controls or in osteoporotic subjects. Moreover, the concentration of elements in bone tissue did not differ in the two groups. These results suggest that the decrease in bone density in osteoporosis is directly related to evolution of the bone mass, without detectable changes in the concentration of elements in bone.

Fluoride reduces the rate of dissolution of bone

Recently, fluoride has been used in the treatment of osteoporosis in an attempt to rebuild bone lost due to this disease. Fluoride has been shown to have a profound effect on osteoblasts and bone formation. Studies have shown that synthetic fluorapatite is more stable and less soluble than hydroxyapatite. This study was designed to determine the dissolution properties of bones from rats fed a normal diet versus rats fed a high fluoride diet. Intact and deproteinized bones were dissolved in buffered solutions, containing physiological amounts of inorganic Ca and P, at pH 3.4, 4.4 and 5.4. The data demonstrate that fluoridated bones dissolve slower than normal bones, deproteinized bones dissolve faster than intact bones and that the initial rate of dissolution of fluoridated bone is always significantly lower than that of normal bone. This may help to explain the reduced rate of osteoclastic resorption in patients undergoing fluoride therapy.