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Maternal & Child Nutrition Jul 2012Exclusive breastfeeding during the first 6 months of infant's life is a public health recommendation and important factor for the promotion of optimal growth, health and...
Exclusive breastfeeding during the first 6 months of infant's life is a public health recommendation and important factor for the promotion of optimal growth, health and behavioural development of each child. The accuracy of the mothers' self-reported past infant-feeding events was examined and compared with the isotopic dilution technique. Breastfeeding practices were assessed in a sample of 44 Cameroonian mother-infant pairs using dietary recall since birth. Intakes of breast milk and non-breast milk water were measured in the same sample using the dose-to-the-mother deuterium-oxide turnover technique and compared with questionnaire. Results showed that mothers' self-reported behaviour overestimates the exclusive breastfeeding rate. Seventy-five per cent of the mothers who claimed to be exclusively breastfeeding were found to be predominantly or partially breastfeeding by the dose-to-the-mother deuterium-oxide turnover technique. Only 11% of the infants were exclusively breastfed, and the breast milk output was not significantly affected (P ≤ 0.05) by the mother's body composition. Mean intakes of breast milk and non-breast milk water were 701 mL day(-1) and 268 mL day(-1), respectively. Introduction of non-breast milk foods is associated with a reduction in the level of breast milk intake, but the difference in breast milk intake was not significant between exclusively and predominantly breastfed infants. In conclusion, the dose-to-the-mother deuterium-oxide turnover technique can be applied to validate the mother's reports of infant-feeding practices, but non-breast milk water intake by breastfeeding category still needs to be normalized.
Topics: Adult; Body Composition; Breast Feeding; Cameroon; Deuterium; Deuterium Oxide; Female; Humans; Indicator Dilution Techniques; Infant; Infant Nutritional Physiological Phenomena; Male; Mental Recall; Milk, Human; Mothers; Self Disclosure; Social Desirability; Young Adult
PubMed: 21426489
DOI: 10.1111/j.1740-8709.2011.00293.x -
The American Journal of Clinical... Nov 2012Dietary β-carotene is the most important precursor of vitamin A. However, the determination of the efficiency of in vivo conversion of β-carotene to vitamin A requires... (Review)
Review
Dietary β-carotene is the most important precursor of vitamin A. However, the determination of the efficiency of in vivo conversion of β-carotene to vitamin A requires sensitive and safe techniques. It presents the following challenges: 1) circulating β-carotene concentration cannot be altered by eating a meal containing ≤6 mg β-carotene; 2) because retinol concentrations are homeostatically controlled, the conversion of β-carotene into vitamin A cannot be estimated accurately in well-nourished humans by assessing changes in serum retinol after supplementation with β-carotene. In the past half-century, techniques using radioisotopes of β-carotene and vitamin A, depletion-repletion with vitamin A and β-carotene supplements, measurement of postprandial chylomicron fractions after consumption of a β-carotene dose, and finally, stable isotopes as tracers to follow the absorption and conversion of β-carotene in humans have been developed. The reported values for β-carotene to vitamin A conversion showed a wide variation from 2 μg β-carotene to 1 μg retinol (for synthetic pure β-carotene in oil) and 28 μg β-carotene to 1 μg retinol (for β-carotene from vegetables). In recent years, a stable isotope reference method (IRM) was developed that used labeled synthetic β-carotene. The IRM method provided evidence that the conversion of β-carotene to vitamin A is likely dose dependent. With the development of intrinsically labeled plant foods harvested from a hydroponic system with heavy water, vitamin A activity of stable isotope-labeled biosynthetic β-carotene from various foods consumed by humans was studied. The efficacy of plant foods rich in β-carotene, such as natural (spinach, carrots, spirulina), hybrid (high-β-carotene yellow maize), and bioengineered (Golden Rice) foods, to provide vitamin A has shown promising results. The results from these studies will be of practical importance in recommendations for the use of pure β-carotene and foods rich in β-carotene in providing vitamin A and ultimately in preventing either overconsumption or poor intake of vitamin A by humans.
Topics: Deuterium Oxide; Food Analysis; Humans; Isotope Labeling; Vitamin A; beta Carotene
PubMed: 23053556
DOI: 10.3945/ajcn.112.034603 -
Annals of Nutrition & Metabolism 2019An objective method of assessing breastfeeding practices is required to evaluate progress toward the World Health Organization Global Target 2025: to increase exclusive...
An objective method of assessing breastfeeding practices is required to evaluate progress toward the World Health Organization Global Target 2025: to increase exclusive breastfeeding (EBF) rates in the first 6 months to at least 50% by 2025. Currently, assessment of EBF at the population level is based on mother or caregiver reporting, which risks recall and social desirability bias. A more objective method is the deuterium oxide dose to mother (DTM) technique, in which lactating mothers are given a small amount of deuterium-labeled water. The infant receives deuterium during breastfeeding, and a compartmental model is used to determine the amount of human milk consumed by the infant, and the exclusivity of breastfeeding practices. If the amount of human milk consumed by an infant is determined using the DTM technique and the concentration of nutritional components or potentially toxic contaminants is measured, then the infant's intake of essential nutrients or environmental contaminants can be ascertained.
Topics: Adult; Africa South of the Sahara; Asia; Body Weight; Breast Feeding; Deuterium Oxide; Eating; Female; HIV Infections; Humans; Infant; Infant, Newborn; Male; Mexico; Micronutrients; Milk, Human; Pesticide Residues; Saliva; Vitamin A Deficiency; Water Supply
PubMed: 31743917
DOI: 10.1159/000503667 -
BMB Reports Jan 2008The present study was aimed to elucidate the mechanism of stabilization of tubulin by deuterium oxide (D(2)O). Rate of decrease of tryptophan fluorescence during aging...
The present study was aimed to elucidate the mechanism of stabilization of tubulin by deuterium oxide (D(2)O). Rate of decrease of tryptophan fluorescence during aging of tubulin at 4 degrees C and 37 degrees C was significantly lower in D(2)O than in H(2)O. Circular dichroism spectra of tubulin after incubation at 4 degrees C, suggested that complete stabilization of the secondary structure in D(2)O during the first 24 hours of incubation. The number of available cysteine measured by DTNB reaction was decreased to a lesser extent in D(2)O than in H(2)O. During the increase in temperature of tubulin, the rate of decrease of fluorescence at 335 nm and change of CD value at 222 nm was lesser in D(2)O. Differential Scanning calorimetric experiments showed that the T(m) values for tubulin unfolding in D(2)O were 58.6 degrees C and 62.17 degrees C, and in H(2)O those values were 55.4 degrees C and 59.35 degrees C.
Topics: Animals; Brain Chemistry; Calorimetry, Differential Scanning; Circular Dichroism; Deuterium Oxide; Fluorescence; Goats; Molecular Conformation; Protein Folding; Protein Structure, Secondary; Temperature; Tubulin
PubMed: 18304452
DOI: 10.5483/bmbrep.2008.41.1.062 -
Journal of Biomedical Optics Nov 2023Changes in lipid, water, and collagen (LWC) content in tissue are associated with numerous medical abnormalities (cancer, atherosclerosis, and Alzheimer's disease)....
SIGNIFICANCE
Changes in lipid, water, and collagen (LWC) content in tissue are associated with numerous medical abnormalities (cancer, atherosclerosis, and Alzheimer's disease). Standard imaging modalities are limited in resolution, specificity, and/or penetration for quantifying these changes. Short-wave infrared (SWIR) photoacoustic imaging (PAI) has the potential to overcome these challenges by exploiting the unique optical absorption properties of .
AIM
This study's aim is to harness SWIR PAI for mapping LWC changes in tissue. The focus lies in devising a reflection-mode PAI technique that surmounts current limitations related to SWIR light delivery.
APPROACH
To enhance light delivery for reflection-mode SWIR PAI, we designed a deuterium oxide (, "heavy water") gelatin (HWG) interface for opto-acoustic coupling, intended to significantly improve light transmission above 1200 nm.
RESULTS
HWG permits light delivery up to 1850 nm, which was not possible with water-based coupling ( light delivery up to 1350 nm). PAI using the HWG interface and the Visualsonics Vevo LAZR-X reveals a signal increase up to 24 dB at 1720 nm in lipid-rich regions.
CONCLUSIONS
By overcoming barriers related to light penetration, the HWG coupling interface enables accurate quantification/monitoring of biomarkers like LWC using reflection-mode PAI. This technological stride offers potential for tracking changes in chronic diseases () and evaluating their responses to therapeutic interventions.
Topics: Deuterium Oxide; Photoacoustic Techniques; Diagnostic Imaging; Water; Lipids
PubMed: 38078156
DOI: 10.1117/1.JBO.28.11.116001 -
Journal of Chemical Information and... Nov 2017An important limitation of standard classical molecular dynamics simulations is the inability to make or break chemical bonds. This restricts severely our ability to...
An important limitation of standard classical molecular dynamics simulations is the inability to make or break chemical bonds. This restricts severely our ability to study processes that involve even the simplest of chemical reactions, the transfer of a proton. Existing approaches for allowing proton transfer in the context of classical mechanics are rather cumbersome and have not achieved widespread use and routine status. Here we reconsider the combination of molecular dynamics with periodic stochastic proton hops. To ensure computational efficiency, we propose a non-Boltzmann acceptance criterion that is heuristically adjusted to maintain the correct or desirable thermodynamic equilibria between different protonation states and proton transfer rates. Parameters are proposed for hydronium, Asp, Glu, and His. The algorithm is implemented in the program CHARMM and tested on proton diffusion in bulk water and carbon nanotubes and on proton conductance in the gramicidin A channel. Using hopping parameters determined from proton diffusion in bulk water, the model reproduces the enhanced proton diffusivity in carbon nanotubes and gives a reasonable estimate of the proton conductance in gramicidin A.
Topics: Deuterium Oxide; Diffusion; Gramicidin; Molecular Dynamics Simulation; Movement; Nanotubes, Carbon; Protein Conformation; Protons; Thermodynamics
PubMed: 29095613
DOI: 10.1021/acs.jcim.7b00603 -
Angewandte Chemie (International Ed. in... Oct 2021The template-directed synthesis of RNA played an important role in the transition from prebiotic chemistry to the beginnings of RNA based life, but the mechanism of RNA...
The template-directed synthesis of RNA played an important role in the transition from prebiotic chemistry to the beginnings of RNA based life, but the mechanism of RNA copying chemistry is incompletely understood. We measured the kinetics of template copying with a set of primers with modified 3'-nucleotides and determined the crystal structures of these modified nucleotides in the context of a primer/template/substrate-analog complex. pH-rate profiles and solvent isotope effects show that deprotonation of the primer 3'-hydroxyl occurs prior to the rate limiting step, the attack of the alkoxide on the activated phosphate of the incoming nucleotide. The analogs with a E ribose conformation show the fastest formation of 3'-5' phosphodiester bonds. Among those derivatives, the reaction rate is strongly correlated with the electronegativity of the 2'-substituent. We interpret our results in terms of differences in steric bulk and charge distribution in the ground vs. transition states.
Topics: Arabinose; Crystallography, X-Ray; DNA Primers; Deuterium Oxide; Imidazoles; Kinetics; Nucleic Acid Conformation; Nucleotides; RNA; Structure-Activity Relationship; Templates, Genetic; Water
PubMed: 34428345
DOI: 10.1002/anie.202109714 -
Chemical & Pharmaceutical Bulletin 2015The current study used 3 types of carrageenan (denoted here as Car)-κ, ι, and λ-to prepare a jelly vehicle for acetaminophen (AAP), and then compared their usefulness...
The current study used 3 types of carrageenan (denoted here as Car)-κ, ι, and λ-to prepare a jelly vehicle for acetaminophen (AAP), and then compared their usefulness as jelly vehicles. The rheological characteristics of each preparation were assessed and then drug elution from the preparation was assessed using dissolution testing. The behavior of each preparation when immersed in water was also examined using magnetic resonance imaging (MRI) in order to better understand the drug elution behaviour of each preparation. Viscoelasticity measurements revealed that 0.75 w/v%-ι-Car and 1.25 w/v%-λ-Car had viscoelasticity values equivalent to that of 0.5 w/v%-κ-Car. Dissolution testing of these 3 preparations indicated that 100% drug elution took 45 min with 0.5 w/v%-κ-Car while it took only 5 min with 0.75 w/v%-ι-Car and 1.25 w/v%-λ-Car. When deuterium oxide was added to κ-Car 0.5%, the MRI images darkened overall starting immediately after addition. The images revealed that the sample and deuterium oxide quickly mixed. In contrast, images revealed that deuterium oxide gradually penetrated κ-Car 1.0%. MRI images had uniform contrast, and deuterium oxide took 6 h or longer to penetrate the samples overall. These findings suggest that water is less apt to penetrate a jelly with an increased car concentration and a denser 3-dimensional network structure. Differences in the structure of car are said to result in better gelling, with κ having the best gelling characteristics, followed by ι and then λ. Thus, this paper discusses the role that vehicle gelling strength plays in the elution of acetaminophen.
Topics: Acetaminophen; Carrageenan; Deuterium Oxide; Elasticity; Gels; Magnetic Resonance Imaging; Viscosity; Water
PubMed: 25877549
DOI: 10.1248/cpb.c15-00097 -
The Journal of General Physiology Jul 2007Determining the mechanisms of flux through protein channels requires a combination of structural data, permeability measurement, and molecular dynamics (MD) simulations....
Determining the mechanisms of flux through protein channels requires a combination of structural data, permeability measurement, and molecular dynamics (MD) simulations. To further clarify the mechanism of flux through aquaporin 1 (AQP1), osmotic p(f) (cm(3)/s/pore) and diffusion p(d) (cm(3)/s/pore) permeability coefficients per pore of H(2)O and D(2)O in AQP1 were calculated using MD simulations. We then compared the simulation results with experimental measurements of the osmotic AQP1 permeabilities of H(2)O and D(2)O. In this manner we evaluated the ability of MD simulations to predict actual flux results. For the MD simulations, the force field parameters of the D(2)O model were reparameterized from the TIP3P water model to reproduce the experimentally observed difference in the bulk self diffusion constants of H(2)O vs. D(2)O. Two MD systems (one for each solvent) were constructed, each containing explicit palmitoyl-oleoyl-phosphatidyl-ethanolamine (POPE) phospholipid molecules, solvent, and AQP1. It was found that the calculated value of p(f) for D(2)O is approximately 15% smaller than for H(2)O. Bovine AQP1 was reconstituted into palmitoyl-oleoyl-phosphatidylcholine (POPC) liposomes, and it was found that the measured macroscopic osmotic permeability coefficient P(f) (cm/s) of D(2)O is approximately 21% lower than for H(2)O. The combined computational and experimental results suggest that deuterium oxide permeability through AQP1 is similar to that of water. The slightly lower observed osmotic permeability of D(2)O compared to H(2)O in AQP1 is most likely due to the lower self diffusion constant of D(2)O.
Topics: Animals; Aquaporin 1; Cattle; Cell Membrane Permeability; Computer Simulation; Deuterium Oxide; Models, Chemical; Models, Molecular; Protein Conformation; Reproducibility of Results; Water
PubMed: 17591989
DOI: 10.1085/jgp.200709810 -
Journal of Materials Chemistry. B May 2020Extracellular vesicles (EVs) are biologically-derived nanovectors important for intercellular communication and trafficking. As such, EVs show great promise as disease...
Extracellular vesicles (EVs) are biologically-derived nanovectors important for intercellular communication and trafficking. As such, EVs show great promise as disease biomarkers and therapeutic drug delivery vehicles. However, despite the rapidly growing interest in EVs, understanding of the biological mechanisms that govern their biogenesis, secretion, and uptake remains poor. Advances in this field have been hampered by both the complex biological origins of EVs, which make them difficult to isolate and identify, and a lack of suitable imaging techniques to properly study their diverse biological roles. Here, we present a new strategy for simultaneous quantitative in vitro imaging and molecular characterisation of EVs in 2D and 3D based on Raman spectroscopy and metabolic labelling. Deuterium, in the form of deuterium oxide (D2O), deuterated choline chloride (d-Chol), or deuterated d-glucose (d-Gluc), is metabolically incorporated into EVs through the growth of parent cells on medium containing one of these compounds. Isolated EVs are thus labelled with deuterium, which acts as a bio-orthogonal Raman-active tag for direct Raman identification of EVs when introduced to unlabelled cell cultures. Metabolic deuterium incorporation demonstrates no apparent adverse effects on EV secretion, marker expression, morphology, or global composition, indicating its capacity for minimally obstructive EV labelling. As such, our metabolic labelling strategy could provide integral insights into EV biocomposition and trafficking. This approach has the potential to enable a deeper understanding of many of the biological mechanisms underpinning EVs, with profound implications for the design of EVs as therapeutic delivery vectors and applications as disease biomarkers.
Topics: Choline; Deuterium Oxide; Extracellular Vesicles; Glucose; Humans; Molecular Imaging; Particle Size; Spectrum Analysis, Raman; Surface Properties; Tumor Cells, Cultured
PubMed: 32373878
DOI: 10.1039/d0tb00620c