Ionized calcium in normal serum, ultrafiltrates, and whole blood determined by ion-exchange electrodes

Moore, Edward W.

doi:10.1172/jci106241

Cited by 446 publications

(218 citation statements)

References 26 publications

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“…They rely on Ca 2þ ions to maintain their elongated structure and enable their adhesive functions (4)(5)(6)(7)(8). The normal physiological extracellular calcium level is 2.12-2.62 mM; with~40% of the Ca 2þ ions binding to proteins and~10% of them bound to various anions in complexes, the corresponding free calcium level is 1.16-1.31 mM (9)(10)(11). In cell culture, a wide range of Ca 2þ concentrations (even as low as 0.02 mM) are sometimes employed (12)(13)(14).…”

Section: Introductionmentioning

confidence: 99%

Cadherin Diffusion in Supported Lipid Bilayers Exhibits Calcium-Dependent Dynamic Heterogeneity

Cai

Shashikanth

Leckband

et al. 2016

Biophysical Journal

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Ca 2þ ions are critical to cadherin ectodomain rigidity, which is required for the activation of adhesive functions. Therefore, changes in Ca 2þ concentration, both in vivo and in vitro, can affect cadherin conformation and function. We employed single-molecule tracking to measure the diffusion of cadherin ectodomains tethered to supported lipid bilayers at varying Ca 2þ concentrations. At a relatively high Ca 2þ concentration of 2 mM, cadherin molecules exhibited a fast diffusion coefficient that was identical to that of individual lipid molecules in the bilayer (D fast z 3 mm 2 /s). At lower Ca 2þ concentrations, where cadherin molecules were less rigid, the ensemble-average cadherin diffusion coefficient was systematically smaller. Individual cadherin trajectories were temporally heterogeneous, exhibiting alternating periods of fast and slow diffusion; the periods of slow diffusion (D slow z 0.1 mm 2 /s) were more prevalent at lower Ca 2þ concentration. These observations suggested that more flexible cadherin ectodomains at lower Ca 2þ concentration alternated between upright and lying-down conformations, where the latter interacted with more lipid molecules and experienced greater viscous drag.

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Section: Introductionmentioning

confidence: 99%

Cadherin Diffusion in Supported Lipid Bilayers Exhibits Calcium-Dependent Dynamic Heterogeneity

Cai

Shashikanth

Leckband

et al. 2016

Biophysical Journal

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“…Of these, the protein-bound fraction represents 30 to 55%, diffusible ionic complexes (e.g., bicarbonate, citrate, sulfate, phosphate lactate) 5 comprise approximately 5 to 15%, and approximately 50% is freely ionized. 6 Most of the protein-bound calcium is complexed to albumin, with the remainder binding to globulins. 5 Experiments by Moore 6 and McLean and Hastings 7,8 confirmed that ionized calcium accounts for the biologically active form of serum calcium and subsequently demonstrated the crucial role of ionized calcium in the calcium homeostasis of healthy individuals and patients with parathyroid abnormalities.…”

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confidence: 99%

“…5 Precision in ionized calcium measurement was revolutionized after the introduction of ion-selective electrodes 10 ; however, the clinical application of this technique was initially limited and delayed by its cost, susceptibility to errors, need to prevent CO 2 losses from the sample, and control of pH. 6 Advances in technology for direct measurement of ionized calcium have decreased the cost and improved its availability in the clinical setting since the 1980s. 11 A number of limitations remain, however, particularly in the outpatient setting, including the technical challenge of equipment maintenance, frequent electrode replacement with associated downtime, and redundancy of instrumentation and personnel, all leading to increased costs.…”

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confidence: 99%

When Is It Appropriate to Order an Ionized Calcium?

Calvi

Bushinsky

2008

Journal of the American Society of Nephrology

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“…Excessive aldosterone induces an expansion of extracellular fluid, which, in turn, may inhibit the tubular reabsorption of calcium in the kidney, thus increasing urinary calcium excretion. Hyperaldosteronism causes hypokalemic alkalosis, which may decrease serum ionized calcium (13). Both changes may lead to lowered serum calcium levels.…”

Section: Discussionmentioning

confidence: 99%

Primary Hyperparathyroidism Associatiated with Aldosterone-Producing Adrenocortical Adenoma and Breast Cancer: Relation to MEN1 Gene

et al. 2004

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A rare case of primary hyperparathyroidism associated with primary aldosteronism and breast cancer is reported. A 44-year-old woman was admitted to our hospital to undergo surgical removal of breast cancer. She had hypertension with low serum potassium, and slightly but significantly elevated serum calcium levels. Further studies demonstrated an enlarged left superior parathyroid gland and a left aldosterone-producing adrenocortical adenoma. Blood pressure was controlled with spironolactone and nifedipine, and left mastectomy was done for breast cancer. The pathological diagnosis was scirrhous breast carcinoma. Although the postoperative course was uneventful, her serum calcium gradually and progressively rose to higher levels. Left superior parathyroidectomy and left adrenalectomy were then performed simultaneously. The pathological diagnoses of the resected parathyroid gland and adrenal gland were parathyroid chief cell adenoma and adrenocortical adenoma with hyperplasia of zona glomerulosa, respectively. To clarify if the occurence of these tumors may be related to MEN1 gene mutations, we analyzed MEN1 gene in this patient, and found a loss of heterozygosity of the MEN1 locus in the parathyroid adenoma and breast cancer. Thus, we conclude that an alteration of the MEN1 gene and/or another tumor suppressor gene located at the MEN1 locus on chromosome 11q13 may be responsible for the development of parathyroid adenoma and breast cancer in our patient suggesting that the clinical spectrum of MEN1 might include breast cancer. In addition, serum calcium should be interpreted with caution in primary aldosteronism, because hypercalcemia may be masked in the presence of aldosterone excess. (Internal Medicine 43: 310-314, 2004)Key words: multiple endocrine neoplasia type 1 (MEN1), MEN1 gene, loss of heterozygosity, breast cancer, primary hyperparathyroidism, primary aldosteronism

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Ionized calcium in normal serum, ultrafiltrates, and whole blood determined by ion-exchange electrodes

Abstract: A B S T R A C T Ion-exchange calcium electrodes represent the first practical method for the direct measurement of ionized calcium [Ca"+] These studies were included as part of a symposium, January 1969 (1) and preliminary reports have appeared previously (2, 3).

Cited by 446 publications

References 26 publications

Cadherin Diffusion in Supported Lipid Bilayers Exhibits Calcium-Dependent Dynamic Heterogeneity

Cadherin Diffusion in Supported Lipid Bilayers Exhibits Calcium-Dependent Dynamic Heterogeneity

When Is It Appropriate to Order an Ionized Calcium?

Primary Hyperparathyroidism Associatiated with Aldosterone-Producing Adrenocortical Adenoma and Breast Cancer: Relation to MEN1 Gene

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