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The Journal of Clinical Investigation Feb 1957
Gastrointestinal water and electroyltes. IV. The equilibration of deuterium oxide (D2O) in gastrointestinal contents and the proportion of total body water (T.B.W.) in the gastrointestinal tract.
Topics: Body Water; Deuterium; Deuterium Oxide; Gastrointestinal Contents; Gastrointestinal Tract; Water
PubMed: 13406040
DOI: 10.1172/JCI103423 -
Biochimica Et Biophysica Acta Jun 2005The bilayer phase transitions of three kinds of phospholipids, dipalmitoylphosphatidylcholine (DPPC), distearoylphosphatidylcholine (DSPC) and...
The bilayer phase transitions of three kinds of phospholipids, dipalmitoylphosphatidylcholine (DPPC), distearoylphosphatidylcholine (DSPC) and dihexadecylphosphatidylcholine (DHPC), in deuterium oxide (D(2)O) and hydrogen oxide (H(2)O) were observed by differential scanning calorimetry (DSC) under ambient pressure and light-transmittance measurements under high pressure. The DSC measurements showed that the substitution of H(2)O by D(2)O affected the pretransition temperatures and the main-transition enthalpies of all PC bilayers. The temperature-pressure phase diagrams for these PC bilayer membranes in both solvents were constructed by use of the data of light-transmittance measurements. Regarding the main transition of all PC bilayer membranes, there was no appreciable difference between the transition temperatures in D(2)O and H(2)O under high pressure. On the other hand, the phase transitions among the gel phases including the pretransition were significantly affected by the solvent substitution. The thermodynamic quantities of phase transitions for the PC bilayer membranes were evaluated and the differences in thermodynamic properties by the water substitution were considered from the difference of interfacial-free energy per molecule in the bilayer in both solvents. It was proved that the substitution of H(2)O by D(2)O causes shrinkage of the molecular area of phospholipid at bilayer interface due to the difference in bond strength between deuterium and hydrogen bonds and produces the great influence on the bilayer phase with the smaller area. Further, the induction of bilayer interdigitation in D(2)O turned out to need higher pressures than in H(2)O.
Topics: 1,2-Dipalmitoylphosphatidylcholine; Calorimetry, Differential Scanning; Deuterium Oxide; Lipid Bilayers; Lipids; Phase Transition; Phosphatidylcholines; Phospholipid Ethers; Phospholipids; Pressure; Temperature; Thermodynamics; Water
PubMed: 15869741
DOI: 10.1016/j.bbamem.2005.03.005 -
The Journal of Nutrition Jun 2015The WHO recommends that exclusive breastfeeding should last up to 6 mo. However, human milk intake of Sri Lankan infants has not been quantified scientifically.
BACKGROUND
The WHO recommends that exclusive breastfeeding should last up to 6 mo. However, human milk intake of Sri Lankan infants has not been quantified scientifically.
OBJECTIVES
The objectives of this study were to measure the human milk intake of Sri Lankan infants during the first 6 mo of age and to document the breastfeeding practices of their mothers.
METHODS
Forty-eight healthy mother-infant dyads were randomly recruited for this cross-sectional study at well-baby clinics. Milk intake was measured using the deuterium oxide-to-the-mother technique over a period of 2 wk. Information on breastfeeding practice and living standards of the participants were gathered using an interviewer-administered questionnaire.
RESULTS
Human milk intake was 672 ± 123 g ⋅ d(-1) (mean ± SD), 776 ± 212 g ⋅ d(-1), and 801 ± 51 g ⋅ d(-1) for infants <2 mo, 2 to <4 mo, and 4-6 mo of age, respectively. The milk intakes were not different among the age groups. Maternal body composition, age, or parity had no effects on milk intake of the infants. However, mother's education : P < 0.05, r = 0.35), infant's age (P < 0.05, r = 0.30), and body mass index (P < 0.05, r = 0.41 : positively correlated with the milk intake. Over 63% of mothers had commenced breastfeeding within 30 min of delivery. About 60% of the mothers were feeding the baby 6-10 times during the daytime and >81% intended to continue exclusive breastfeeding until 6 mo of age.
CONCLUSION
This study, for the first time, documented the adequacy of breast-milk intake among Sri Lankan infants and the nutrition status of the mothers.
Topics: Adult; Body Composition; Body Mass Index; Breast Feeding; Cross-Sectional Studies; Deuterium Oxide; Female; Healthy Volunteers; Humans; Infant; Infant Nutritional Physiological Phenomena; Milk, Human; Nutritional Status; Socioeconomic Factors; Sri Lanka; Surveys and Questionnaires; Young Adult
PubMed: 25904731
DOI: 10.3945/jn.115.211771 -
Journal of Dairy Science Jan 1986In three experiments patterns of water turnover and body composition estimated by deuterium oxide were studied in Holstein cows. In the first experiment, four lactating...
In three experiments patterns of water turnover and body composition estimated by deuterium oxide were studied in Holstein cows. In the first experiment, four lactating cows were infused with deuterium oxide, and blood samples were taken during 4-d collection. Milking was stopped; cows were reinfused with deuterium oxide and resampled. Slopes of deuterium oxide dilution curves indicated lactating cows turned water over more rapidly than nonlactating cows. In the second experiment with the same four cows, during 4-d collection, deuterium oxide concentrations in milk, urine, and feces showed dilution patterns similar to deuterium oxide in blood. Sampling milk may be an alternative to sampling blood. In the third experiment, 36 Holstein cows were fed 55, 65, or 75% alfalfa, smooth bromegrass, or equal parts of each forage as total mixed rations; remaining portions of rations were a grain mixture. Body composition was estimated at -1, 1, 2, 3, 4, and 5 mo postpartum. Empty body water, protein, mineral, fat, and fat percentage decreased from prepartum to postpartum. First calf heifers contained less empty body water, protein, and mineral than older cows. Cows fed diets with 55% forage had more body fat than those fed diets with 75% forage. Cows fed alfalfa-based diets had more gastrointestinal fill regardless of grain than cows fed diets that contained alfalfa and smooth bromegrass. Gastrointestinal fill of cows increased from prepartum to 5 mo postpartum.
Topics: Animals; Body Composition; Cattle; Deuterium; Deuterium Oxide; Feces; Female; Lactation; Milk; Pregnancy; Radioisotope Dilution Technique; Rumen; Water
PubMed: 3009575
DOI: 10.3168/jds.S0022-0302(86)80373-3 -
Annals of Surgery Aug 1957
Topics: Deuterium; Deuterium Oxide; Gastrointestinal Tract; Water
PubMed: 13459272
DOI: 10.1097/00000658-195708000-00013 -
PloS One 2018To perform in vitro high-resolution 900 MHz magnetic resonance spectroscopy (NMR) analysis of human brain tumor tissue extracts and analyze for the oncometabolite...
PURPOSE
To perform in vitro high-resolution 900 MHz magnetic resonance spectroscopy (NMR) analysis of human brain tumor tissue extracts and analyze for the oncometabolite 2-hydroxyglutarate (2HG) and other brain metabolites, not only for 1H but also for 13C with indirect detection by heteronuclear single quantum correlation (HSQC).
MATERIAL AND METHODS
Four surgically removed human brain tumor tissue samples were used for extraction and preparation of NMR samples. These tissue samples were extracted with 4% perchloric acid and chloroform, freeze-dried, then dissolved into 0.28 mL of deuterium oxide (D2O, 99.9 atom % deuterium) containing 0.025 wt % sodium 3-(trimethylsilyl)propionate-2,2,3,3-d4 (TSP). All samples were adjusted to pH range of 6.9-7.1 before finally transferred to 5 mm Shigemi™ NMR microtube. NMR experiments were performed on Bruker DRX 900 MHz spectrometer with 1H/13C/15N Cryo-probe™ with Z-gradient, without further temperature control for the samples. All chemical shift values were presented relative to TSP at 0.00 ppm for both 1H and 13C. 1H 1D, 1H-13C HSQC, 1H-1H correlation spectroscopy (COSY) and 1H-13C heteronuclear multiple bond correlation (HMBC) spectra were acquired and analyzed.
RESULTS
2-hydroxyglutarate, an oncometabolite associated with gliomas with IDH mutations, was successfully detected and assigned by both 1H-13C HSQC and 1H-1H COSY experiments as well as 1H 1D experiments in two of the tissue samples. In particular, to our knowledge this work shows the first example of detecting 900 MHz 13C-NMR spectral lines of 2-hydroxyglutarate in human brain tumor tissue samples. In addition to the oncometabolite 2-hydroxyglutarate, at least 42 more metabolites were identified from our series of NMR experiment.
CONCLUSION
The detection of 2-hydroxyglutarate and other metabolites can be facilitated by homonuclear and heteronuclear two-dimensional 900 MHz NMR spectroscopy even in case of real tumor tissue sample extracts without physical separation of metabolites.
Topics: Brain; Brain Neoplasms; Carbon-13 Magnetic Resonance Spectroscopy; Chloroform; Deuterium Oxide; Glioma; Glutarates; Humans; Hydrogen-Ion Concentration; Perchlorates; Propionates; Proton Magnetic Resonance Spectroscopy; Reproducibility of Results; Tissue Extracts; Trimethylsilyl Compounds
PubMed: 30192797
DOI: 10.1371/journal.pone.0203379 -
ELife Nov 2020Microscale processes are critically important to soil ecology and biogeochemistry yet are difficult to study due to soil's opacity and complexity. To advance the study...
Microscale processes are critically important to soil ecology and biogeochemistry yet are difficult to study due to soil's opacity and complexity. To advance the study of soil processes, we constructed transparent soil microcosms that enable the visualization of microbes via fluorescence microscopy and the non-destructive measurement of microbial activity and carbon uptake in situ via Raman microspectroscopy. We assessed the polymer Nafion and the crystal cryolite as optically transparent soil substrates. We demonstrated that both substrates enable the growth, maintenance, and visualization of microbial cells in three dimensions over time, and are compatible with stable isotope probing using Raman. We applied this system to ascertain that after a dry-down/rewetting cycle, bacteria on and near dead fungal hyphae were more metabolically active than those far from hyphae. These data underscore the impact fungi have facilitating bacterial survival in fluctuating conditions and how these microcosms can yield insights into microscale microbial activities.
Topics: Bacillus subtilis; Bacteria; Carbon Isotopes; Deuterium Oxide; Dimethylpolysiloxanes; Fluorescent Dyes; Fluorocarbon Polymers; Fungi; Isotope Labeling; Mucor; Particle Size; Sodium Fluoride; Soil; Soil Microbiology; Spectrum Analysis, Raman
PubMed: 33140722
DOI: 10.7554/eLife.56275 -
Biochimica Et Biophysica Acta Nov 2001Actin filament velocities in an in vitro motility assay system were measured both in heavy water (deuterium oxide, D(2)O) and water (H(2)O) to examine the effect of... (Comparative Study)
Comparative Study
Actin filament velocities in an in vitro motility assay system were measured both in heavy water (deuterium oxide, D(2)O) and water (H(2)O) to examine the effect of D(2)O on the actomyosin interaction. The dependence of the sliding velocity on pD of the D(2)O assay solution showed a broad pD optimum of around pD 8.5 which resembled the broad pH optimum (pH 8.5) of the H(2)O assay solution, but the maximum velocity (4.1+/-0.5 microm/s, n=11) at pD 8.5 in D(2)O was about 60% of that (7.1+/-1.1 microm/s, n=11) at pH 8.5 in H(2)O. The K(m) values of 95 and 80 microM and V(max) values of 3.2 and 5.1 microm/s for the D(2)O and H(2)O assay were obtained by fitting the ATP concentration dependence of the velocity (at pD and pH 7.5) to the Michaelis-Menten equation. The K(m) value of actin-activated Mg-ATPase activity of myosin subfragment 1 (S1) was decreased from 50 microM [actin] in H(2)O to 33 microM [actin] in D(2)O without any significant changes in V(max) (9.4 s(-1) in D(2)O and 9.3 s(-1) in H(2)O). The rate constants of ADP release from the acto-S1-ADP complex measured by the stopped flow method were 361+/-26 s(-1) (n=27) in D(2)O and 512+/-39 s(-1) (n=27) in H(2)O at 6 degrees C. These results suggest that the decrease in the in vitro actin-myosin sliding velocity in D(2)O results from a slowing of the release of ADP from the actomyosin-ADP complex and the increase in the affinity of actin for myosin in the presence of ATP in D(2)O.
Topics: Actin Cytoskeleton; Actomyosin; Adenosine Diphosphate; Animals; Ca(2+) Mg(2+)-ATPase; Deuterium Oxide; Hydrogen-Ion Concentration; Kinetics; Myosins; Rabbits; Rheology; Water
PubMed: 11779555
DOI: 10.1016/s0005-2728(01)00216-x -
Journal of Lipid Research Sep 2022De novo lipogenesis (DNL) converts carbon substrates to lipids. Increased hepatic DNL could contribute to pathogenic liver triglyceride accumulation in nonalcoholic...
De novo lipogenesis (DNL) converts carbon substrates to lipids. Increased hepatic DNL could contribute to pathogenic liver triglyceride accumulation in nonalcoholic steatohepatitis (NASH) and therefore may be a potential target for pharmacological intervention. Here, we measured hepatic DNL using heavy water in 123 patients with NASH with fibrosis or cirrhosis, calculated the turnover of hepatic triglycerides to allow repeat labeling studies, and determined the associations of hepatic DNL with metabolic, fibrotic, and imaging markers. We found that hepatic DNL was higher in patients with fibrotic NASH [median (IQR), 40.7% contribution to palmitate (32.1, 47.5), n=103] than has been previously reported in healthy volunteers and remained elevated [median (IQR), 36.8% (31.0, 44.5), n=20] in patients with cirrhosis, despite lower liver fat content. We also showed that turnover of intrahepatic triglyceride pools was slow (t >10 days). Furthermore, DNL contribution was determined to be independent of liver stiffness by magnetic resonance imaging but was positively associated with the number of large very low density lipoprotein (VLDL) particles, the size of VLDL, the lipoprotein insulin resistance score, and levels of ApoB100, and trended toward negative associations with the fibrosis markers FIB-4, FibroSure, and APRI. Finally, we found treatment with the acetyl-CoA carboxylase inhibitor firsocostat reduced hepatic DNL at 4 and 12 weeks, using a correction model for residual label that accounts for hepatic triglyceride turnover. Taken together, these data support an important pathophysiological role for elevated hepatic DNL in NASH and demonstrate that response to pharmacological agents targeting DNL can be correlated with pretreatment DNL.
Topics: Acetyl-CoA Carboxylase; Biomarkers; Carbon; Deuterium Oxide; Fibrosis; Humans; Lipogenesis; Lipoproteins, VLDL; Liver; Liver Cirrhosis; Non-alcoholic Fatty Liver Disease; Palmitates; Triglycerides
PubMed: 35835205
DOI: 10.1016/j.jlr.2022.100250 -
Biophysical Journal Mar 1999Hydrogen-deuterium exchange has been monitored by solid-state NMR to investigate the structure of gramicidin M in a lipid bilayer and to investigate the mechanisms for...
Hydrogen-deuterium exchange has been monitored by solid-state NMR to investigate the structure of gramicidin M in a lipid bilayer and to investigate the mechanisms for polypeptide insertion into a lipid bilayer. Through exchange it is possible to observe 15N-2H dipolar interactions in oriented samples that yield precise structural constraints. In separate experiments the pulse sequence SFAM was used to measure dipolar distances in this structure, showing that the dimer is antiparallel. The combined use of orientational and distance constraints is shown to be a powerful structural approach. By monitoring the hydrogen-deuterium exchange at different stages in the insertion of peptides into a bilayer environment it is shown that dimeric gramicidin is inserted into the bilayer intact, i.e., without separating into monomer units. The exchange mechanism is investigated for various sites and support for a relayed imidic acid mechanism is presented. Both acid and base catalyzed mechanisms may be operable. The nonexchangeable sites clearly define a central core to which water is inaccessible or hydroxide or hydronium ion is not even momentarily stable. This provides strong evidence that this is a nonconducting state.
Topics: Binding Sites; Biophysical Phenomena; Biophysics; Deuterium; Deuterium Oxide; Dimerization; Gramicidin; Hydrogen; Lipid Bilayers; Magnetic Resonance Spectroscopy; Models, Molecular; Peptides; Protein Conformation; Solubility
PubMed: 10049303
DOI: 10.1016/S0006-3495(99)77282-6