One-hour test for estimating intestinal absorption of calcium by using stable strontium as a marker

1994 ◽  
Vol 40 (2) ◽  
pp. 257-259 ◽  
Author(s):  
A J Sips ◽  
J C Netelenbos ◽  
R Barto ◽  
P Lips ◽  
W J van der Vijgh
Keyword(s):  
Clinical Practice ◽  
Intestinal Absorption ◽  
Broad Spectrum ◽  
Calcium Metabolism ◽  
Calcium Absorption ◽  
Area Under The Curve ◽  
Close Correlation ◽  
Reliable Information ◽  
Simple Test ◽  
Stable Strontium

Abstract Intestinal absorption of calcium is a relevant marker in a broad spectrum of diseases; however, its determination in clinical practice is difficult. Our aim was to design a simple test for this based on stable strontium (88Sr). The correlation between the intestinal absorption of simultaneously administered 45Ca and 88Sr was investigated in patients with various disorders of the bone and calcium metabolism. The area under the curve for the period 0-60 min after dosing (AUC0-60 in mmol.L-1.min), being a representative measure of intestinal absorption, showed a close correlation between both elements (r = 0.90, P < 0.001). Moreover, the measure of agreement in classifying the patients as low, intermediate, or high absorbers was high (kappa = 0.80). We conclude that a test based on measuring AUC0-60 of strontium is a fast and inexpensive way to obtain reliable information about the level of intestinal calcium absorption.

scholarly journals Simple test of intestinal calcium absorption measured by stable strontium.

BMJ ◽  
1987 ◽  
Vol 295 (6592) ◽  
pp. 231-234 ◽  
Author(s):  
S Milsom ◽  
K Ibbertson ◽  
S Hannan ◽  
D Shaw ◽  
J Pybus
Keyword(s):  
Calcium Absorption ◽  
Intestinal Calcium Absorption ◽  
Simple Test ◽  
Stable Strontium

Calcium Metabolism in Children Suffering from Homozygous ß-Thalassaemia after Oral Administration of 47Ca

1976 ◽  
Vol 15 (02) ◽  
pp. 77-79 ◽  
Author(s):  
D. Liakakos ◽  
P. Ylachos ◽  
Ch. Anoussakis ◽  
C. Constantinides ◽  
I. Tsakalosos
Keyword(s):  
Oral Administration ◽  
Intestinal Absorption ◽  
Calcium Metabolism

SummaryThe study of calcium metabolism in ten thalassaemic children comperatively with controls after oral administration of 47Ca has shown diminished intestinal absorption. It is suggested that this finding is propably related in part with the pathogenesis of the osteoporosis in thalassaemia.

Stable Strontium Absorption as a Measure of Intestinal Calcium Absorption: Comparison with the Double-Radiotracer Calcium Absorption Test

1994 ◽  
Vol 87 (3) ◽  
pp. 363-368 ◽  
Author(s):  
Aubrey Blumsohn ◽  
Brian Morris ◽  
Richard Eastell
Keyword(s):  
Renal Failure ◽  
Chronic Renal Failure ◽  
Time Course ◽  
Calcium Absorption ◽  
Quadratic Term ◽  
The Mean ◽  
Stable Strontium ◽  
The Relationship ◽  
Dual Tracer ◽  
Fractional Absorption

1. Stable strontium (Sr) has been proposed as an alternative to calcium (Ca) isotopes for the measurement of intestinal Ca absorption. The aim of this study was to compare the time course and fractional absorption of Ca and Sr, when both are measured using dual-tracer techniques. 2. 45Ca and Sr absorption tests were carried out on consecutive days in patients with osteoporosis (n = 10) or chronic renal failure (n = 7). Both tests were repeated in four patients with chronic renal failure after treatment with calcitriol (1 μg daily for 10 days). 3. The time course of Ca absorption was determined using the 85Sr (intravenous)/45Ca (oral) dual-tracer technique, and the time course of Sr absorption using 85Sr (intravenous)/stable Sr (oral). Oral tracers were administered on consecutive days with a test meal containing 5.3 mmol of Ca and 2.5 mmol of either stable Sr or Ca carrier. The fractional absorption of 45Ca and Sr at 6 h (FA360) and the absorption rate as a function of time were calculated by deconvolution. 4. The mean FA360 for Sr (20.2%) was lower than the mean FA360 for 45Ca (37.8%, P < 0.001, paired t-test), but the time course of Sr absorption was similar to that of Ca. There was a significant correlation between the FA360 for 45Ca and Sr, although the relationship was improved by including a quadratic term (R2 = 0.89, P < 0.001, significance of quadratic term, P < 0.05). After 1,25-dihydroxyvitamin D treatment, the FA360 of stable Sr increased 4.29-fold, whereas the FA360 of 45Ca increased only 2.4-fold. 5. Although the fractional absorption of Sr determined by dual-tracer deconvolution was the best predictor of FA360 for 45Ca, little was lost by confining the analysis to a single serum Sr measurement taken 3 h or more after oral administration. 6. We conclude that Sr absorption is qualitatively similar to that of Ca, although absorption of Sr is much lower than that of Ca. Furthermore, the relationship does not appear to be linear. Stable Sr may be useful in place of Ca isotopes in the routine clinical evaluation of Ca absorption.

Preclinical screening of the applicability of strontium as a marker for intestinal calcium absorption

1997 ◽  
Vol 272 (3) ◽  
pp. E422-E428 ◽  
Author(s):  
A. J. Sips ◽  
R. Barto ◽  
J. C. Netelenbos ◽  
W. J. van der Vijgh
Keyword(s):  
Body Weight ◽  
Calcium Absorption ◽  
Intestinal Calcium Absorption ◽  
Dose Finding ◽  
Male Rats ◽  
Controlled Study ◽  
Dihydroxyvitamin D3 ◽  
Before And After ◽  
Stable Strontium ◽  
Preclinical Screening

The applicability of stable strontium as a marker for measuring intestinal calcium absorption is mainly dependent on the validity of the assumption that calcium and strontium are absorbed with a constant ratio. Up to now, it is not clear whether this ratio is affected by intervention therapy. Therefore, preclinical screening of this ratio before and after treatment is indispensable for a clinical calcium absorption test based on the use of stable strontium as a marker. We studied the effects of 1,25-dihydroxyvitamin D3 [1,25(OH)2D(3)], a potent enhancer of active intestinal calcium absorption, on the pharmacokinetics of both calcium-45 and strontium in adult male rats, in a short-term dose-finding study [0-50 ng 1,25(OH)2D(3)/100 g body weight] and also in a placebo-controlled study in which 12.5 ng 1,25(OH)2D(3)/100 g body weight were applied to assess the long-term pharmacokinetics. The mean bioavailability (true absorption) was 33% for calcium and 19% for strontium (ratio 1.7:1), whereas, after 1,25(OH)2D(3) pretreatment, it was 73 and 43% (ratio 1.7:1), respectively. These findings demonstrate that intestinal strontium absorption has, like intestinal calcium absorption, an active component. Moreover, they underscore the applicability of stable strontium as a tool for investigating calcium absorption under various conditions.

Antimicrobial peptides in silkworm

2019 ◽  
Vol 69 (4) ◽  
pp. 391-410 ◽  
Author(s):  
Zhi Li ◽  
Yan Ma ◽  
Xuan Liu ◽  
Yi Li ◽  
Fangyin Dai
Keyword(s):  
Antioxidant Activity ◽  
Clinical Practice ◽  
Antimicrobial Peptides ◽  
Structure Function ◽  
Broad Spectrum ◽  
Antibacterial Properties ◽  
Antimicrobial Activities ◽  
Vital Role ◽  
Bacteria Resistance

Abstract Antimicrobial peptides (AMPs) are a type of small molecular proteins that play a vital role in the resistance to alien pathogens. AMPs are widespread in bacteria, archaea, protists, fungi, plants and animals. AMPs have a broad spectrum of antimicrobial activities and they rarely induce bacteria resistance; thus, they are thought to be good candidates for antibiotics in clinical practice. Recently, AMPs are increasingly attracting attention because of their outstanding features and functions. In addition to their known antibacterial properties, some kinds of AMPs have also been reported to have antiviral, anticancer, antiparasitic, and antioxidant activity. In this review, we introduce the diversity of AMPs, including their structure, function and related mechanisms. We focus primarily on recent studies of silkworm AMPs and summarize their classification, activities and possible mechanisms. Finally, based on the review, probable directions and perspectives for studies of the AMPs of silkworm are discussed and proposed.

Action of 1,25-dihydroxyvitamin D3 and a diphosphonate on calcium metabolism in rats

1975 ◽  
Vol 229 (2) ◽  
pp. 402-408 ◽  
Author(s):  
JP Bonjour ◽  
U Trechsel ◽  
H Fleisch ◽  
R Schenk ◽  
HF DeLuca ◽  
...  
Keyword(s):  
Calcium Metabolism ◽  
Calcium Absorption ◽  
Bone Mineralization ◽  
Concomitant Administration ◽  
Urinary Calcium ◽  
Intestinal Calcium Absorption ◽  
Bone Morphology ◽  
Dihydroxyvitamin D3 ◽  
Calcium Retention ◽  
Endogenous Production

The effect of 1,25-dihydroxycholecalciferol (1,25-(OH)2D3) on Ca balance, 45Ca kinetics, and bone morphology has been studied in control rats and rats given disodium ethane-1-hydroxy-1,1-diphosphonate (EHDP), 10 mg P/kg sc per day. This large dose of EHDP is known to inhibit bone mineralization and intestinal calcium absorption and to depress the endogenous production of 1,25-(OH)2D3. In conctrol rats, 1,25-(OH)2D3 increased intestinal calcium absorption. However, in contrast to the enhanced calcium absorption that results from an augmentation of dietary calcium, the 1,25(OH)2D3-induced augmentation of calcium absorption does not lead to a rise in calcium retention, the intestinal effect being matched by an increased excretion of urinary calcium. The EHDP-induced decrease of intestinal calcium absorption could be completely prevented by the concomitant administration of 1,25-(OH)2D3 but not the inhibition of bone mineralization. Therefore, in contrast to the impairment of calcium absorption, that of bone mineralization brought about by large doses of EHDP cannot be merely attributed to a decreased production of 1,25-(OH)2D3.

scholarly journals A Moving Target—Vancomycin Therapeutic Monitoring

2020 ◽  
Vol 9 (4) ◽  
pp. 474-478
Author(s):  
Alaina N Burns ◽  
Jennifer L Goldman
Keyword(s):  
Clinical Practice ◽  
Therapeutic Drug Monitoring ◽  
Drug Monitoring ◽  
Clinical Care ◽  
Area Under The Curve ◽  
Therapeutic Monitoring ◽  
Therapeutic Drug ◽  
Moving Target ◽  
Efficacy And Safety ◽  
Vancomycin Trough

Abstract Therapeutic drug monitoring (TDM) has been a common practice to optimize efficacy and safety of vancomycin. While vancomycin trough-only TDM has widely been integrated into pediatric clinical practice since 2009, recently updated vancomycin TDM guidelines published in March 2020 recommend area under the curve (AUC) based TDM for vancomycin instead of trough-only TDM. In this review, we discuss the rationale behind the change in TDM recommendations, describe two approaches for calculating vancomycin AUC in clinical practice, and address considerations for integrating vancomycin AUC TDM into pediatric clinical practice. Our primary goal is to provide pediatric clinicians with a resource for implementing vancomycin AUC monitoring into clinical care.

REVERSAL OF BETAMETHASONE-INDUCED INHIBITION OF INTESTINAL CALCIUM ABSORPTION BY 1α-HYDROXYCHOLECALCIFEROL

1978 ◽  
Vol 78 (2) ◽  
pp. 187-194 ◽  
Author(s):  
J. FOX ◽  
A. D. CARE ◽  
D. H. MARSHALL
Keyword(s):  
Absorption Coefficient ◽  
Oral Administration ◽  
Intestinal Absorption ◽  
Calcium Absorption ◽  
Mean Value ◽  
Intestinal Calcium Absorption ◽  
Control Value ◽  
Isotope Technique ◽  
Intravenous And Oral Administration ◽  
Double Isotope

SUMMARY The intestinal absorption of calcium has been studied in conscious, unstressed pigs, using a modification of the double isotope technique. The oral administration of betamethasone (1 mg/day) to four pigs (25–33 kg) for 4 weeks reduced the calcium absorption coefficient, calculated after the intravenous and oral administration of 47Ca2+, by a mean value of 66%. The oral administration of 1α-hydroxycholecalciferol (2 μg/day) in combination with betamethasone (1 mg/day) for a further 4 weeks returned the absorption coefficient to the control value.

scholarly journals Improved Dried Blood Spot-Based Metabolomics: A Targeted, Broad-Spectrum, Single-Injection Method

Metabolites ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 82 ◽  
Author(s):  
Kefeng Li ◽  
Jane C. Naviaux ◽  
Jonathan M. Monk ◽  
Lin Wang ◽  
Robert K. Naviaux
Keyword(s):  
Blood Volume ◽  
Broad Spectrum ◽  
Area Under The Curve ◽  
Dried Blood Spots ◽  
Extraction Methods ◽  
Storage Conditions ◽  
Metabolomic Analysis ◽  
Blood Samples ◽  
One Year ◽  
Blood Spot

Dried blood spots (DBS) have proven to be a powerful sampling and storage method for newborn screening and many other applications. However, DBS methods have not yet been optimized for broad-spectrum targeted metabolomic analysis. In this study, we developed a robust, DBS-based, broad-spectrum, targeted metabolomic method that was able to measure over 400 metabolites from a 6.3 mm punch from standard Whatman 903TM filter paper cards. The effects of blood spot volumes, hematocrit, vacutainer chemistry, extraction methods, carryover, and comparability with plasma and fingerstick capillary blood samples were analyzed. The stability of over 400 metabolites stored under varying conditions over one year was also tested. No significant impacts of blood volume and hematocrit variations were observed when the spotted blood volume was over 60 µL and the hematocrit was between 31% and 50%. The median area under the curve (AUC) of metabolites in the DBS metabolome declined by 40% in the first 3 months and then did not decline further for at least 1 year. All originally detectable metabolites remained within detectable limits. The optimal storage conditions for metabolomic analysis were −80 °C with desiccants and without an O2 scavenger. The method was clinically validated for its potential utility in the diagnosis of the mitochondrial disease mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS). Our method provides a convenient alternative to freezing, storing, and shipping liquid blood samples for comparative metabolomic studies.

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