Use of stable48Ca in the clinical measurement of intestinal calcium absorption

Neer, R.; Tully, George L.; Schatz, Peter J.; Hnatowich, Donald J.

doi:10.1007/bf02013226

Cited by 16 publications

(7 citation statements)

References 15 publications

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“…Therefore, stable isotope-labeled research products, such as microspheres, will have a significantly longer shelf life compared with alternative labeling methods. Several researchers have proposed using neutron activation in conjunction with enriched or biologically rare isotopes as substitutes for radioactive isotopes in laboratory experiments (12,26) and in clinical applications (5,11,19). Kitchin et al (12), for example, successfully used neutron activation to measure iodine and bromine for the assay of 5-iodo-2Ј-deoxyuridine and 5-bromo-2Ј-deoxyuridine as DNA precursors for the determination of cell mitosis and death rates.…”

Section: H111mentioning

confidence: 99%

Stable labeled microspheres to measure perfusion: validation of a neutron activation assay technique

Reinhardt

Dalhberg

Tries

et al. 2001

American Journal of Physiology-Heart and Circulatory Physiology

125

109

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Neutron activation is an accurate analytic method in which trace quantities of isotopes of interest in a sample are activated and the emitted radiation is measured with high-resolution detection equipment. This study demonstrates the application of neutron activation for the measurement of myocardial perfusion using stable isotopically labeled microspheres. Stable labeled and standard radiolabeled microspheres (15 microm) were coinjected in an in vivo rabbit model of myocardial ischemia and reperfusion. Radiolabeled microspheres were detected with a standard gamma-well counter, and stable labeled microspheres were detected with a high-resolution Ge detection after neutron activation of the myocardial and reference blood samples. Regional myocardial blood flow was calculated from the deposition of radiolabeled and stable labeled microspheres. Both sets of microspheres gave similar measurements of regional myocardial blood flow over a wide range of flow with a high linear correlation (r = 0.95-0.99). Neutron activation is capable of detecting a single microsphere in an intact myocardial sample while providing simultaneous quantitative measurements of multiple isotope labels. This high sensitivity and capability for measuring perfusion in intact tissue are advantages over other techniques, such as optical detection of microspheres. Neutron activation also can provide an effective method for reducing the production of low-level radioactive waste generated from biomedical research. Further applications of neutron activation offer the potential for measuring other stable labeled compounds, such as fatty acids and growth factors, in conjunction with microsphere measured flow, providing the capability for simultaneous measurement of regional metabolism and perfusion.

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Section: H111mentioning

confidence: 99%

Stable labeled microspheres to measure perfusion: validation of a neutron activation assay technique

Reinhardt

Dalhberg

Tries

et al. 2001

American Journal of Physiology-Heart and Circulatory Physiology

125

109

View full text Add to dashboard Cite

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“…), or as radioisotope tracers in clinical investigations for understanding Ca homeostasis in health and disease (Neer et al . ; Smith et al . ).…”

Section: Introductionmentioning

confidence: 99%

Suitability of Solanum lycopersicum L. ‘Microtom’ for growth in Bioregenerative Life Support Systems: exploring the effect of high‐LET ionising radiation on photosynthesis, leaf structure and fruit traits

et al. 2019

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The realisation of manned space exploration requires the development of Bioregenerative Life Support Systems (BLSS). In such self-sufficient closed habitats, higher plants have a fundamental role in air regeneration, water recovery, food production and waste recycling. In the space environment, ionising radiation represents one of the main constraints to plant growth.• In this study, we explore whether low doses of heavy ions, namely Ca 25 Gy, delivered at the seed stage, may induce positive outcomes on growth and functional traits in plants of Solanum lycopersicum L. 'Microtom'. After irradiation of seed, plant growth was monitored during the whole plant life cycle, from germination to fruit ripening. Morphological parameters, photosynthetic efficiency, leaf anatomical functional traits and antioxidant production in leaves and fruits were analysed.• Our data demonstrate that irradiation of seeds with 25 Gy Ca ions does not prevent achievement of the seed-to-seed cycle in 'Microtom', and induces a more compact plant size compared to the control. Plants germinated from irradiated seeds show better photochemical efficiency than controls, likely due to the higher amount of D1 protein and photosynthetic pigment content. Leaves of these plants also had smaller cells with a lower number of chloroplasts. The dose of 25 Gy Ca ions is also responsible for positive outcomes in fruits: although developing a lower number of berries, plants germinated from irradiated seeds produce larger berries, richer in carotenoids, ascorbic acid and anthocyanins than controls.• These specific traits may be useful for 'Microtom' cultivation in BLSS in space, in so far as the crew members could benefit from fresh food richer in functional compounds that can be directly produced on board.Plant Biology 21 (2019) 615-626

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“…Stable ( 42 Ca, 44 Ca, and 46 Ca) and short-lived radioactive isotopes ( 45 Ca and 47 Ca) of calcium have been used to study calcium metabolism for years (1)(2)(3). Limitations of the stable isotopes are that they are expensive to purify and that relatively large doses need to be given to distinguish the exogenously administered tracer from the naturally occurring signal.…”

confidence: 99%

41Ca and Accelerator Mass Spectrometry to Monitor Calcium Metabolism in End Stage Renal Disease Patients

et al. 2005

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Background: Monitoring bone resorption with measurements of bone density and biochemical markers is indirect. We hypothesized that bone resorption can be studied directly by serial measurements of the ratio 41 Ca/Ca in serum after in vivo labeling of calcium pools with 41 Ca. We report the preparation of an intravenous 41 Ca dose suitable for humans, an analytical method for determining 41 Ca/Ca isotope ratios in biological samples, and studies in human volunteers. Methods:41 Ca was formulated and aliquoted into individual vials, and to the extent possible, the 41 Ca doses were tested according to US Pharmacopeia (USP) guidelines. A 10 nCi dose of 41 Ca was administered intravenously to 4 end stage renal disease (ESRD) patients on hemodialysis and 4 healthy control individuals. Distribution kinetics were determined over 168 days. Calcium was isolated with 3 precipitation steps and a cationexchange column, and 41 Ca/Ca ratios in serum were then measured by accelerator mass spectrometry. Results: The dosing solution was chemically and radiologically pure, contained <0.1 endotoxin unit/mL, and passed USP sterility tests. Quantification of 41 Ca/Ca ratios was linear from 6 ؋ 10 ؊14 to 9.1 ؋ 10 ؊10 . The run-to-run imprecision (as CV) of the method was 4% at 4.6 ؋ 10 ؊11 and 6% at 9.1 ؋ 10 ؊10 . The area under the curve of 41 Ca in the central compartment vs time was

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Use of stable48Ca in the clinical measurement of intestinal calcium absorption

Cited by 16 publications

References 15 publications

Stable labeled microspheres to measure perfusion: validation of a neutron activation assay technique

Stable labeled microspheres to measure perfusion: validation of a neutron activation assay technique

Suitability of Solanum lycopersicum L. ‘Microtom’ for growth in Bioregenerative Life Support Systems: exploring the effect of high‐LET ionising radiation on photosynthesis, leaf structure and fruit traits

41Ca and Accelerator Mass Spectrometry to Monitor Calcium Metabolism in End Stage Renal Disease Patients

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