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 cation-exchange 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 x 10(-14) to 9.1 x 10(-10). The run-to-run imprecision (as CV) of the method was 4% at 4.6 x 10(-11) and 6% at 9.1 x 10(-10). The area under the curve of (41)Ca in the central compartment vs time was significantly less for ESRD patients than for controls (P < 0.005).
Conclusions: Isotope ratios spanning 5 orders of magnitude can be measured by accelerator mass spectrometry with excellent precision in the range observed in samples collected from patients who have received 10 nCi of (41)Ca. The (41)Ca at this dose caused no adverse effects in 8 volunteers. This is the first report of the use of (41)Ca to monitor differences in bone turnover between healthy individuals and ESRD patients.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1373/clinchem.2005.049650 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Effect of genetic and vascular risk factors on rates of cognitive decline in early-onset and late-onset Alzheimer's disease.
J Alzheimers Dis
January 2025
Department of Neurology, Indiana University School of Medicine, Indianapolis, IN, USA.
Background: Although previous studies have shown that cognitive decline in Alzheimer's disease (AD) is associated with various risk factors, they primarily focused on late-onset AD (LOAD).
Objective: We aim to evaluate the differential impact of risk factors on the cognitive decline between early-onset AD (EOAD, onset < 65 years) and LOAD (onset 65 years) and explore the longitudinal effect of Apolipoprotein E allele 4 ( ε4) on cortical atrophy in both cohorts.
Methods: Using data from 212 EOAD and 1101 LOAD participants in the Alzheimer's Disease Neuroimaging Initiative (ADNI), we conducted multivariable mixed-effect models to evaluate the impact of ε4, education, hypertension, diabetes, dyslipidemia, and body mass index on cognitive performance.
Anorexia nervosa is associated with higher brain mu-opioid receptor availability.
Mol Psychiatry
January 2025
Turku PET Centre, University of Turku, Turku, Finland.
Anorexia nervosa (AN) is a severe psychiatric disorder, characterized by restricted eating, fear to gain weight, and a distorted body image. Mu-opioid receptor (MOR) functions as a part of complex opioid system and supports both homeostatic and hedonic control of eating behavior. Thirteen patients with AN and thirteen healthy controls (HC) were included in this study.
View Article and Find Full Text PDFUnraveling the mechanisms underlying AOM-induced deterioration of the settling performance of algal floc.
Water Res
January 2025
School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China; Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China. Electronic address:
The influence of algal organic matter (AOM) on the settling performance of algal flocs remains poorly understood. To address this, we employed fractionation techniques based on molecular weight to isolate different AOM fractions and analyzed their effects on floc structure and settling performance. This involved comparing the concentrations, compositions, potentials, and functional groups of organic matter before and after coagulation-sedimentation.
View Article and Find Full Text PDFHigher concentration of trehalose dihydrate stabilizes recombinant IgG1 under forced stress conditions.
J Pharm Sci
January 2025
Department of Chemical Engineering, Indian Institute of Technology Delhi. Electronic address:
Stability of complex biotherapeutics like monoclonal antibodies is paramount for their safe and efficacious use. Excipients are inactive ingredients that are added to the purified product so as to offer it a stable environment. Trehalose dihydrate is a non-reducing sugar that is commonly used as a stabilizing agent in biotherapeutic formulations under liquid and frozen states.
View Article and Find Full Text PDFBackground: In settings with low pneumococcal conjugate vaccine (PCV) coverage, multi-age cohort mass campaigns could increase population immunity, and fractional dosing could increase affordability. We aimed to evaluate the effect of mass campaigns on nasopharyngeal pneumococcal carriage of Pneumosil (PCV10) in children aged 1-9 years in Niger.
Methods: In this three-arm, open-label, cluster-randomised trial, 63 clusters of one to four villages in Niger were randomly assigned (3:3:1) using block randomisation to receive campaigns consisting of a single full dose of a 10-valent PCV (Pneumosil), a single one-fifth dose of Pneumosil, or no campaign.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!