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Assessment of 47Ca Distribution and Biological Half-Life in Japanese Quail Chicks

ABSTRACT

A study was conducted to assess 47Calcium (47Ca) distribution and biological half-life in different body organs of Japanese quail chicks. A total of 85, 4 week old chicks, were dosed with 1ml/chick volume of 1% (w/v) CaCl2 solution containing 7.51x10-08 Ci 47Ca which is equivalent to 1.27x10-13 g. 47Ca activity, in terms of decay per minute (DPM), was measured in different body organs at 12 hours time intervals, after 24 hours from ingestion for five days. The total activity of 47Ca for each organ and activity per gram of organ (D.min-1.g-1) was calculated. Data were Statistically analyzed using completely randomized design (CRD), one way analysis of variance (ANOVA) as per the procedure given by SPSS (2002), 9.0 version for Windows. The results obtained indicated that following 47Ca administration most of the total 47Ca concentration was found in the bones with count rates of 110267±550 DPM. While in the fifth day following administration, most of the 47Ca was found in the feathers with a total activity of 13322±760 DPM. The biological half-life time was found to be highest in the heart and kidneys, respectively compared to the other body organs. In conclusion, the current results suggest that the main excretory pathway for Ca is through the skin. Regarding organ dependency on Ca for the normal functioning, the results obtained in our study suggest that the heart is the most dependent organ on Ca.

Keywords:
47 Ca Distribution; quail chicks; biological half-life

INTRODUCTION

Calcium (Ca) has been recognized as an essential nutrient in poultry nutrition. It considers the highest abundant mineral in the body (Veum, 2010Veum TL. Phosphorus and calcium nutrition and metabolism. In: Vitti MSS, Kebreab E, editors. Phosphorus and calcium utilization and requirements in farm animals Oxfordshire: CAB International; 2010. p.94-111.), required to sustain biological processes of various body functions such as: the ossification of bones and cardiac muscle activity, vascular contraction, activation of several enzymes, transmission of nerve impulses, intracellular signaling, and hormonal secretion, etc., (Pu et al., 2016). Adequate Ca intake is essential for the healthy functioning of bone, heart, muscles, blood and nerves, etc., while, Ca deficiency, Ca metabolism disorders (Weaver, 2014Weaver CM. Ca supplementation: is protecting against osteoporosis counter to protecting against cardiovascular disease? Current Osteoporosis Reports 2014;12:211-218.), factors that influence Ca absorption efficiency and thus influence requirements for Ca and also, any change in serum Ca homeostasis can affect one or more of these physiological functions (Shin & Kim, 2015Shin CS, Kim KM. The risks and benefits of Ca supplementation. Endocrinology Metabolism 2015;30(1):27-34.). All these factors are subject to increase the risk of various bone diseases and lead to economic losses to farm holders, (Brini et al., 2013Brini M, Ottolini D, CaliT, Carafoli E. Ca in health and disease. Metal Ions in Life Sciences 2013;(13):81-137.). In order for these processes to function properly, normal Ca ion levels in blood and extracellular Ca homeostasis of various body organs, such as the intestine, muscles, and bone tissue must be maintained within a narrow range (Brini et al., 2013; Brown, 2013Brown EM. Role of the Ca-sensing receptor in extracellular Ca homeostasis. Best Practice Research Clinical Endocrinology Metabolism 2013;27(3):333-343.). As reviewed above, it is necessary to have a detailed understanding of Ca absorption and metabolism of different body organs. Ca radioactive isotope (47Ca), the most valuable tool for many Ca studies and biological investigations, has been widely used as tracer dietary studies on the uptake, transport and absorption of Ca in biological materials, through the intestinal wall (Reynard et al., 2013Reynard LM, Pearson JA, Henderson GM, Hedges REM. (Ca isotopes in juvenile milk consumers. Archaeometry 2013;55:946-957.; Melin et al., 2014Melin AD, Crowley BE, Brown ST, Wheatley PV, Moritz GL, Yu Y, et al. Technical Note: Ca and carbon stable isotope ratios as paleodietary indicators. American Journal of Physical Anthropology 2014;154:633-643.; Heuser, 2016Heuser A. Biomedical application of Ca stable isotopes. In: Gussone N, Heuse A, Schmitt AD, Wombacher F. Advances in isotope geochemistry. Heidelberg: Springer Nature; 2016. p. 247-260.). The importance attributed to 47Ca is due to the special properties of this isotope, it is naturally fractionated between different organs and body fluids (Moynier & Fujii, 2017Moynier F, Fujii T. Calcium isotope fractionation between aqueous compounds relevant to low-temperature geochemistry, biology and medicine. Scientific Reports 2017;7:44255.) and eliminated from the body with a biological half-life of 4.5 days, which is long enough for numerous biological investigations and short enough to ensure that the body subjected to the investigation is not under prolonged irradiation. It emits gamma rays in addition to beta rays, and since the gamma rays are capable of penetrating many centimeters of tissue, determination of 47Ca in the body is possible by external measurements. It is therefore, possible to monitor the Ca movements during different body organs and to investigate the metabolic path of Ca in the body: its absorption through the walls of the intestine into the blood, its deposition in the skeleton, its return to the blood and its excretion, through 47Ca measurements. Since, no reference has been made to trace Ca throughout the body organs of Japanese quail chicks. Therefore, the aim of the present study, was to assess 47Ca distribution and biological half-life in different body organs of Japanese quail chicks and define more closely the specific Ca requirements or the amount of Ca required for each organ using the 47Ca.

MATERIALS AND METHODS

Production of 47Ca

Five grams of Ca chloride, technical grade (Sigma-Aldrich), was placed in a polyethylene vial and irradiated in the thermal irradiation site of the second research reactor (ETRR-2) for 5 hours irradiation at thermal flux of ~ 2 x1011 n.cm-2.s-1. After proper cooling time, 47Ca activity was detected and measured using gamma ray spectrometer consisting of a high performance calibrated germanium (HPGe) detector associated with the necessary electronics for data acquisition and processing.

Birds’ ethics and husbandry

All of the experiments were carried out according to the guidelines of the Institutional Animal Care and Use Committee (IACUC) for animal experiments, which is member in the Egyptian Network of Research Ethics Committee (ENERC). The scientific and ethics committee of the Biological Application Department, Nuclear Research Center, Egypt approved all procedures used in this experiment (protocol number 174; date of approval: 08-03-2018).

The experimental study was conducted on Japanese quail chicks maintained at the Poultry experimental farm of the biological Application Department, Nuclear Research Center, Egypt. All procedures used in this experiment were approved by the Animal Ethics Committee of National Institute of Animal Health and complied with the “Guidelines for the Care and Use of Animals in Research”.

Birds, Treatment, Samples and Measurements

A total number of 150 Japanese quail (Coturnix coturnix japonica) chicks, at 4 weeks of age with average body weight of 128±5g/ chick, were used for this study. The chicks were reared in battery cages of 30 × 60 × 150 cm in size and kept under the same environmental conditions of light 23:1 hrs Light: dark cycle, RH was 50±5% and room temperature (30±2ºC).

The rearing conditions were 25±2ºC, 60±5% relative humidity (RH), with a photoperiod of 14 L: 10 D hours

RH was 50±5% and photoperiod was 14 L: 10 D hours.

Feed and water were provided ad libitum. Chicks, equal in body weight, were evenly distributed into 3 replications, each replicate pen containing 50 quails each. For one week (the treatment period), the quail chicks were fed the basal diet formulated to meet all nutrient requirements of Japanese quail according to (NRC, 1994), with protein level (22 %), metabolizable energy (3350 kcal/kg), Ca level (0.81%) and available phosphorus level (0.31%).

At the beginning of the treatment (time of ingestion), the activity of 47Ca was measured using a gamma ray spectrometer consisting of a calibrated HPGe detector and found to be 7.51µCi/g CaCl2 which is equivalent to 1.27x 10-11 g 47Ca since that the 47Ca specific activity is 5.9 × 105 Ci/g. The radio activity half life time (t1/2) of 47Ca is 4.5 days (Reynard et al. 2013Reynard LM, Pearson JA, Henderson GM, Hedges REM. (Ca isotopes in juvenile milk consumers. Archaeometry 2013;55:946-957.).

All chicks were administered orally 1ml volume/ chick of 1% (w/v) CaCl2 solution containing 7.51x10-08 Ci 47Ca which was equivalent to 1.27x10-13g 47Ca. After a 24-hour period following the administration, 6 quail chicks (2 chicks /pen) were randomly selected, weighed and slaughtered for carcass analysis: feather, skeletal muscles from breast and thigh, bones, liver, proventriculus, gizzard, intestine, kidney, and heart for each slaughtered chick were calculated and weighed individually. Excreta was also collected. Blood samples were collected from each slaughter chick into test tubes. For assay of the total Ca47 content, each body organ and blood per chick was counted immediately for one-minute using gamma-counter in the term of decay per minute per gram (D/min/g) of organ. The same procedure was repeated at 12 hour intervals following the administration for five days. The data obtained were analyzed to estimate the bio-distribution and biological half life time of Ca for each organ.

47 Ca detection and amount of 47 Ca calculations per gram organ

The 47Ca specific activity was employed to calculate both of the approximate total amount of 47Ca (g) and the approximate amount of 47Ca per gram organ at measuring time intervals.

The calculations of 47Ca effective half life time (t1/2e) and biological half-life time (t1/2b) were performed according to (Segel, 1976Segel IH. Biochmical calculations. 2nd ed. Ontario: Wiley and Sons; 1976. p.441.) as follows:

t1/2e, in hours, was calculated according to the following equation:

t 1 / 2 e = 0.693 x ( A A o ) / 2.3 log t o / t

Where Ao and A are any given activities of 47Ca at time to and t

t1/2b, in minutes, of 47Ca in the chicks were calculated using the following equation:

t 1 / 2 b = ( ( 1 / t 1 / 2 e ) ( 1 / ( T 1 / 2 p x 24 ) ) ) x 60

Where T1/2p is the physical half life time of 47Ca which equals 4.5 days.

Statistical analysis

Statistical analysis was done using completely randomized design (CRD), one way analysis of variance (ANOVA) as per the procedure given by SPSS (2002SPSS. Program. User guide for personal computer. Cary: SAS Institute; 2002.), 9.0 version for Windows. The test was employed to identify the significant differences amongst the different time, organs and feaces. P-value less than 0.05 is considered to be statistically significant.

RESULTS AND DISCUSSION

47 Ca distribution throughout the body

47Ca total activity in DPM was tracked in various body organs of quail chick after 24 hours following administration and equivalent calculated amounts of 47Ca in gram at 24-hour time intervals are summarized in Tables (1 and 2). As shown in Figure (1), the results obtained shows that, most of the total 47Ca was found, as expected, in the bones which had 47Ca count rates of 110267±550, 53747±2072, 60416±4188, and 46630±3232 DPM at 24, 48, 72, 96 hours following the administration, respectively. These count rates represented 67%, 48%, 56%, and 56%, in respect to the above mentioned count rates, of the total 47Cadetected at mentioned times. At 120 hours after ingestion it was noticed that the count rate of 47Ca was the highest in the feathers where 47Ca activity recorded 13342±760 DPM and represented about 34% of the total detected activity, while in the bones, the 47Ca recorded 11692±501 DPM and represented about 30% of the total detected activity. These results give obvious evidence that the main site of storage for Ca in terms of 47Ca is in the bones which correlates with most of the studies and references (Taylor & Bushinsky, 2009Taylor JG, Bushinsky DA. Ca and phosphorus homeostasis. Blood Purification 2009;27:387-394.; Lieben et al., 2010; Carmeli et et al., 2015; Pu et al., 2016). The above results also suggest that the main route of deposition and excretion of Ca may be through the skin and feathers, since the Ca amount, in terms of 47Ca activity, was found to increase in the feathers as experimental time advanced. As a result, feathers can be a reliable indicator to detect the correlations between oral ingestion of 47Ca and its deposition in feathers and skin of quail chicks. Many investigators have used feathers as a simple method for biomonitoring to determine trace element levels, dietary exposure and external contamination in birds (Cardiel et al., 2011Cardiel IE, Taggart MA, Mateo R. Using Pb-Al ratios to discriminate between internal and external deposition of Pb in feathers. Ecotoxicology Environmental Safety 2011;74:911-917.; Brait & Antoniosi Filho, 2011Brait CHH, Antoniosi Filho NR. Use of feathers of feral pigeons (Columba livia) as a technique for metal quantification and environmental monitoring. Environmental Monitoring and Assessment 2011;179:457- 467.; Jenni et al., 2015Jenni L, Madry MM, Kraemer T, Kupper J, Naegeli H, Jenny H, et al. The frequency distribution of lead concentration in feathers, blood, bone, kidney and liver of golden eagles Aquila chrysaetos: insights into the modes of uptake. Journal of Ornithology 2015;156(4):1095-1103.). In skeletal muscles 47Ca activity appears after 48 h of 47Ca ingestion, recorded 12494±705 DPM and represented about 11% of the total detected activity, then a slight decrease occurred to 3619±190 DPM and represented about 9% of the total detected activity at 120 h of 47Ca ingestion. This result of 47Ca activity in skeletal muscles confirms the essential role of Ca in muscles contraction as shown in many studies (Sun et al., 2009Sun YB, Lou F, Irving M. Ca- and myosin-dependent changes in troponin structure during activation of heart muscle. Journal of Physiology 2009;587:155-163; Brini et al., 2013Brini M, Ottolini D, CaliT, Carafoli E. Ca in health and disease. Metal Ions in Life Sciences 2013;(13):81-137.; Brown, 2013Brown EM. Role of the Ca-sensing receptor in extracellular Ca homeostasis. Best Practice Research Clinical Endocrinology Metabolism 2013;27(3):333-343.; Weaver, 2014Weaver CM. Ca supplementation: is protecting against osteoporosis counter to protecting against cardiovascular disease? Current Osteoporosis Reports 2014;12:211-218.; Pu et al., 2016).

Figure 1
47Ca total activity distribution through experimental time of the study.

Table 1
Total Calculated Activity of 47Ca (Mean±SD) in different body organs and excreta at 24 hour time intervals measured after 24 hours from the ingestion.

Table 2
Approximate total amount of 47Ca in different body organs and excreta at 24 hour time intervals measured after 24 hours from the ingestion.

47 Ca amount per gram tissue of each body organs

In this part of the study, the correlation between 47Ca activity in DPM per gram organ and equivalent calculated amounts in gram per gram organ at 12 hr time intervals until 120 hours of the administration time are presented in Tables (3 and 4) and in Figures (2 and 3).

Table 3
Activity of 47Ca per gram (Mean±SD) in different body organs and excreta at 12 hour time intervals measured after 24 hours from the ingestion

Table 4
Approximate amount of 47Ca in different body organs and excreta at 12 hour time intervals measured after 24 hours from the ingestion.

Table 5
effective half life time (t1/2e) and biological half life time (t1/2b ) of 47Ca in Japanese quail body organs under study.

Figure 2
distribution of 47Ca activity, per gram organ, in organs which found to have the highest per gram organ expressed as percentage from total 47 Ca activities throughout the time of the study.

Figure 3
distribution of 47Ca activity, per gram organ, in organs which found to have the lowest expressed as percentage from total 47Ca activities throughout time of the study.

It was found that the picture changed when we studied the Ca requirements in terms of 47Ca per gram in the studied organs, as shown in Figures (1 and 3) and detailed hereafter. The 47Ca count rates in DPM per gram of organ at 24 hours after administration in the blood, feather, skeletal muscles, bones, intestine, liver, kidneys, gizzard, proventriculus, heart and excreta was found to be 661±46.24, 2891.3±241.79, 258±11.04, 1078.3±14.39, 460.3±11.57, 1317±48.7, 1364±55.8, 1326.7±80.38, 3651.7±134.1, 2101±188.5 and 556±16.4, respectively. As a result, the highest 47Ca activities per gram organ were detectable at 24 h after ingestion in the proventriculus, feather and heart (23.31, 18.46 and 13.41%), respectively, of total estimated 47Ca activity, with intermediate activities in kidney, gizzard, liver and bones (8.71, 8.47, 8.41, and 6.88%), respectively, and low activities in intestine, blood, skeletal muscles and excreta (2.94, 4.22, 1.65 and 3.55%), respectively. With progress in time, starting from the 24th h until the 72nd h of the administration time, gradual decreases were recorded for the percentage of 47Ca activity per gram in all organs and excreta, except the bones in which the 47Ca reached 40% of total activity in the studied organs. The observed decreases in 47Ca activity with progress of time, as observed in many studies (Khanal & Nemera, 2008Khanal RC, Nemere I. Regulation of intestinal Ca transport, Annual Review of Nutrition 2008;28:179-196.; Geibel & Hebert, 2009Geibel JP, Hebert SC. The functions and roles of the extracellular Ca2+-sensing receptor along the intestine. Annual Reviews Physiology 2009;71:205-217.; Christakos, 2012Christakos S. Mechanism of action of 1,25-dihydroxyvitamin D3 on intestinal Ca absorption. Reviews Endocrinology Metabolic Disordes 2012;13(1):39-44.), confirmed the intestinal absorption and Ca metabolism, which refers to the movements and regulation of Ca into and out of various body compartments of quail chick, such as the intestine, the blood plasma, the extracellular and the intracellular fluid, and the bone tissue. The observed patterns of 47Ca in bones bone tissue acts as a Ca storage center for deposits and withdrawals needed by the blood, via continual bone remodeling (Morgan et al., 2012Morgan JLL, Skulan JL, Gordon GW, Romaniello SJ, Smith SM, Anbar AD. Rapidly assessing changes in bone mineral balance using natural stable Ca isotopes. Proceedings of the National Academy of Sciences of the United States of America 2012;109:9989-9994; Brini et al., 2013Brini M, Ottolini D, CaliT, Carafoli E. Ca in health and disease. Metal Ions in Life Sciences 2013;(13):81-137.; Brown, 2013Brown EM. Role of the Ca-sensing receptor in extracellular Ca homeostasis. Best Practice Research Clinical Endocrinology Metabolism 2013;27(3):333-343.; Carmeli et et al., 2015). Most studies on the physiology of muscles showed that the muscles require Ca to contract, by increasing the amount of free intracellular Ca into the muscle cells (Ewing & Charlton, 2007Ewing W, Charlton SJ. Ca. In: The minerals directory. 2nd ed. Leicestershire: Context Products Ltd; 2007. p.5a-5f.; Pu et al., 2016; Shin & Kim, 2015Shin CS, Kim KM. The risks and benefits of Ca supplementation. Endocrinology Metabolism 2015;30(1):27-34.; Heuser, 2016Heuser A. Biomedical application of Ca stable isotopes. In: Gussone N, Heuse A, Schmitt AD, Wombacher F. Advances in isotope geochemistry. Heidelberg: Springer Nature; 2016. p. 247-260.). In Skeletal muscles, liver, gizzard, intestine and excreta, it was noticed that, with progress of time starting from the 24th h towards the end of the measuring time at the 120th h of administration, 47Ca activity per gram these organs decreased gradually and reached 0.56, 5, 5.28, 1.06, and 0.72%, respectively, of the total estimated 47Ca activity. While, a slight increase was detected gradually in the behavior of 47Ca activity per gram of kidney, starting from the 84th h towards the end of measuring time at the 120th h of administration time, and reached 16.79% of the total estimated 47Ca activity. Similarly, a slight increase was detected gradually in the behavior of 47Ca activity per gram of heart from 10% at the 84th h to 20.2% of the total estimated 47Ca activity at the 120th h of administration time. Depending on the previous results, it can be concluded that the observed decrease in 47Ca activity per gram of liver, gizzard, intestine and excreta after 24 h following the administration in this study is logically since the majority of the Ca, approximately 65%, is absorbed throughout the intestine but varies by region to provide a Ca pool to maintain serum levels (Pu et al., 2016; Heuser, 2016). Furthermore, most studies on Ca2+ homoeostasis in hepatic tissue have suggested a dynamic equilibrium between separate Ca2+ influx and Ca2+ efflux pathways (Reinhart et al., 1984Reinhart PH, Pol EV, Taylor WM, Bygrave FL. An assessment of the Ca content of rat liver mitochondria in vivo. Biochemical Jorurnal 1984;218:415-420.). Moreover, these results may indicate that the quail´s body reached the Ca balance state which is determined by the relationship between Ca intake and Ca absorption and excretion. Ewing & Charlton (2007) reported that, the Ca requirement is generally recognized to be the intake required to maintain Ca balance and therefore skeletal integrity. Examination of the data clearly detected a constant behavior of 47Ca activity per gram of blood at approximately 3% of the total estimated 47Ca activity which occur for 5 days following the administration. As a result, the regulation of Ca in the blood plasma is within narrow limits. As such, this may explain why an important aspect of Ca metabolism is plasma Ca homeostasis (Pu et al., 2016).

The biological half life time (t1/2b) of 47Ca

The calculated biological half life time (t1/2b) in minutes of 47Ca and the highest t1/2b for 47Ca activity, are shown in Figure (4), and are found to be 101.1, 48.2, and 10.9, 6.2 minutes in the heart, kidney, bones and feathers respectively. The calculated biological half-life values tended to increase with the increase in the Ca retention in the heart which may suggest that the heart muscle is the most dependent organ on Ca for proper functioning. In this respect, (Kranias et al., 2007Kranias EG, Bers DM, Dibb KM, Graham HK, Venetucci LA, Eisner DA, et al. Analysis of cellular Ca fluxes in cardiac muscle to understand Ca homeostasis in the heart. Cell Calcium 2007;42:503-512.; Bers, 2008Bers DM. Ca cycling and signaling in cardiac myocytes. Annual Review Physiology 2008;70:23-49.; Sun et al., 2009Sun YB, Lou F, Irving M. Ca- and myosin-dependent changes in troponin structure during activation of heart muscle. Journal of Physiology 2009;587:155-163) showed that Ca has an essential role in cardiac muscle physiology (Excitation contraction coupling), allowing the heart to function as a whole to contract properly and pump the blood efficiently into the arteries throughout the body. It was also showed that 47Ca t1/2b is higher in the kidneys than int he bones, this finding may be related to the primary mechanism of kidney for rapid release or absorption of Ca through the filtration and excretion functions. (Toka et al., 2015Toka HR, Pollak MR, Houillier P. Ca sensing in the renal tubule. Physiology 2015;30(4):317-326.) showed that extra intestinal Ca can be processed through the kidneys and removed from the body through excretion, however, when correlated to the above total findings of total 47Ca activity of feather, we found that the main secretion pathway of Ca is through the skin rather than the kidneys due to the feather´s much greater size compared to the kidneys. Finally, the calculated t1/2b suggest that, although Ca is apparently mainly deposited and utilized by the bones of quail chick, this is not the case on the specialized tissue levels of body organs where it was revealed using 47Ca measurements and t1/2b that the Ca retention in the heart is the highest, therefore there is minimal turnover and reduced exchange of calcium molecules between heart muscle cells and blood which may suggest that the heart muscle it the most dependent organ on Ca for proper functioning.

Figure 4
t1/2b (min) of 47Ca in different Quail body organs under study *(t1/2b): biological half-life time

CONCLUSION

The results of the present study have provided a means for closely monitoring 47Ca distribution throughout body organs which may occur following the administration in quail chicks and furthermore they allow a realistic estimation of the Ca content to be made and examine the ability of body organs to maintain a given 47Ca load. Most of the total 47Ca was found in the bones. While in the fifth day following the administration most the 47Ca was found in the feathers. The highest biological half-life time was found to be in the heart and kidney, respectively. As a result, the heart is the most dependent organ on Ca requirements for the normal functioning and the main excretory pathway for Ca is through the skin.

REFERENCES

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  • Brait CHH, Antoniosi Filho NR. Use of feathers of feral pigeons (Columba livia) as a technique for metal quantification and environmental monitoring. Environmental Monitoring and Assessment 2011;179:457- 467.
  • Brini M, Ottolini D, CaliT, Carafoli E. Ca in health and disease. Metal Ions in Life Sciences 2013;(13):81-137.
  • Brown EM. Role of the Ca-sensing receptor in extracellular Ca homeostasis. Best Practice Research Clinical Endocrinology Metabolism 2013;27(3):333-343.
  • Cardiel IE, Taggart MA, Mateo R. Using Pb-Al ratios to discriminate between internal and external deposition of Pb in feathers. Ecotoxicology Environmental Safety 2011;74:911-917.
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  • Christakos S. Mechanism of action of 1,25-dihydroxyvitamin D3 on intestinal Ca absorption. Reviews Endocrinology Metabolic Disordes 2012;13(1):39-44.
  • Ewing W, Charlton SJ. Ca. In: The minerals directory. 2nd ed. Leicestershire: Context Products Ltd; 2007. p.5a-5f.
  • Geibel JP, Hebert SC. The functions and roles of the extracellular Ca2+-sensing receptor along the intestine. Annual Reviews Physiology 2009;71:205-217.
  • Heuser A. Biomedical application of Ca stable isotopes. In: Gussone N, Heuse A, Schmitt AD, Wombacher F. Advances in isotope geochemistry. Heidelberg: Springer Nature; 2016. p. 247-260.
  • Jenni L, Madry MM, Kraemer T, Kupper J, Naegeli H, Jenny H, et al. The frequency distribution of lead concentration in feathers, blood, bone, kidney and liver of golden eagles Aquila chrysaetos: insights into the modes of uptake. Journal of Ornithology 2015;156(4):1095-1103.
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  • Morgan JLL, Skulan JL, Gordon GW, Romaniello SJ, Smith SM, Anbar AD. Rapidly assessing changes in bone mineral balance using natural stable Ca isotopes. Proceedings of the National Academy of Sciences of the United States of America 2012;109:9989-9994
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  • Reynard LM, Pearson JA, Henderson GM, Hedges REM. (Ca isotopes in juvenile milk consumers. Archaeometry 2013;55:946-957.
  • Segel IH. Biochmical calculations. 2nd ed. Ontario: Wiley and Sons; 1976. p.441.
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Publication Dates

  • Publication in this collection
    20 Dec 2019
  • Date of issue
    2019

History

  • Received
    11 Feb 2019
  • Accepted
    22 July 2019
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