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Pflugers Archiv : European Journal of... Jun 2024Increase in transendothelial water permeability is an essential etiological factor in a variety of diseases like edema and shock. Despite the high clinical relevance,...
Increase in transendothelial water permeability is an essential etiological factor in a variety of diseases like edema and shock. Despite the high clinical relevance, there has been no precise method to detect transendothelial water flow until now. The deuterium oxide (DO) dilution method, already established for measuring transepithelial water transport, was used to precisely determine the transendothelial water permeability. It detected appropriate transendothelial water flow induced by different hydrostatic forces. This was shown in four different endothelial cell types. The general experimental setup was verified by gravimetry and absorbance spectroscopy. Determination of transendothelial electrical resistance (TEER) and immunocytochemical staining for proteins of the cell-cell contacts were performed to ensure that no damage to the endothelium occurred because of the measurements. Furthermore, endothelial barrier function was modulated. Measurement of transendothelial water flux was verified by measuring the TEER, the apparent permeability coefficient and the electrical capacity. The barrier-promoting substances cyclic adenosine monophosphate and iloprost reduced TEER and electrical capacity and increased permeability. This was accompanied by a reduced transendothelial water flux. In contrast, the barrier-damaging substances thrombin, histamine and bradykinin reduced TEER and electrical capacity, but increased permeability. Here, an increased water flow was shown. This newly established in vitro method for direct measurement of transendothelial water permeability was verified as a highly precise technique in various assays. The use of patient-specific endothelial cells enables individualized precision medicine in the context of basic edema research, for example regarding the development of barrier-protective pharmaceuticals.
Topics: Deuterium Oxide; Humans; Electric Impedance; Water; Endothelial Cells; Permeability; Animals; Endothelium, Vascular; Capillary Permeability; Human Umbilical Vein Endothelial Cells
PubMed: 38438679
DOI: 10.1007/s00424-024-02934-z -
The Journal of Physiology Feb 2024We measured the impact of blood flow restriction on muscle protein synthesis rates, muscle mass and strength during 2 weeks of strict bed rest. Twelve healthy, male...
We measured the impact of blood flow restriction on muscle protein synthesis rates, muscle mass and strength during 2 weeks of strict bed rest. Twelve healthy, male adults (age: 24 ± 3 years, body mass index: 23.7 ± 3.1 kg/m ) were subjected to 14 days of strict bed rest with unilateral blood flow restriction performed three times daily in three 5 min cycles (200 mmHg). Participants consumed deuterium oxide and we collected blood and saliva samples throughout 2 weeks of bed rest. Before and immediately after bed rest, lean body mass (dual-energy X-ray absorptiometry scan) and thigh muscle volume (magnetic resonance imaging scan) were assessed in both the blood flow restricted (BFR) and control (CON) leg. Muscle biopsies were collected and unilateral muscle strength (one-repetition maximum; 1RM) was assessed for both legs before and after the bed rest period. Bed rest resulted in 1.8 ± 1.0 kg lean body mass loss (P < 0.001). Thigh muscle volume declined from 7.1 ± 1.1 to 6.7 ± 1.0 L in CON and from 7.0 ± 1.1 to 6.7 ± 1.0 L in BFR (P < 0.001), with no differences between treatments (P = 0.497). In addition, 1RM leg extension strength decreased from 60.2 ± 10.6 to 54.8 ± 10.9 kg in CON and from 59.2 ± 12.1 to 52.9 ± 12.0 kg in BFR (P = 0.014), with no differences between treatments (P = 0.594). Muscle protein synthesis rates during bed rest did not differ between the BFR and CON leg (1.11 ± 0.12 vs. 1.08 ± 0.13%/day, respectively; P = 0.302). Two weeks of bed rest substantially reduces skeletal muscle mass and strength. Blood flow restriction during bed rest does not modulate daily muscle protein synthesis rates and does not preserve muscle mass or strength. KEY POINTS: Bed rest, often necessary for recovery from illness or injury, leads to the loss of muscle mass and strength. It has been postulated that blood flow restriction may attenuate the loss of muscle mass and strength during bed rest. We investigated the effect of blood flow restriction on muscle protein synthesis rates, muscle mass and strength during 2 weeks of strict bed rest. Blood flow restriction applied during bed rest does not modulate daily muscle protein synthesis rates and does not preserve muscle mass or strength. Blood flow restriction is not effective in preventing muscle atrophy during a prolonged period of bed rest.
PubMed: 38411283
DOI: 10.1113/JP286065 -
Biochemistry Mar 2024Production of soluble proteins is essential for structure/function studies; however, this usually requires milligram amounts of protein, which can be difficult to obtain...
Production of soluble proteins is essential for structure/function studies; however, this usually requires milligram amounts of protein, which can be difficult to obtain with traditional expression systems. Recently, the Gram-negative bacterium emerged as a novel and alternative host platform for production of proteins in high yields. Here, we used a commercial strain derived from (Vmax X2) to produce soluble bacterial and fungal proteins in milligram scale, which we struggled to achieve in . These proteins include the cholera toxin (CT) and -acetyl glucosamine-binding protein A (GbpA) from , the heat-labile enterotoxin (LT) from and the fungal nematotoxin CCTX2 from . CT, GbpA, and LT are secreted by the Type II secretion system in their natural hosts. When these three proteins were produced in Vmax, they were also secreted and could be recovered from the growth media. This simplified the downstream purification procedure and resulted in considerably higher protein yields compared to production in (6- to 26-fold increase). We also tested Vmax for protein perdeuteration using deuterated minimal media with deuterium oxide as solvent and achieved a 3-fold increase in yield compared to the equivalent protocol in . This is good news, since isotopic labeling is expensive and often ineffective but represents a necessary prerequisite for some structural biology techniques. Thus, Vmax represents a promising host for production of challenging expression targets and for protein perdeuteration in amounts suitable for structural biology studies.
Topics: Escherichia coli; Vibrio; Enterotoxins; Cholera Toxin
PubMed: 38359344
DOI: 10.1021/acs.biochem.3c00612 -
African Health Sciences Sep 2023This study aims to evaluate the relation of body mass index (BMI) to fat mass among children by two techniques impedancemetry and deuterium oxide dilution (DO).
OBJECTIVES
This study aims to evaluate the relation of body mass index (BMI) to fat mass among children by two techniques impedancemetry and deuterium oxide dilution (DO).
METHODS
This study was carried out in 156 schoolchildren aged between 8 and 11 years. The children received interrogation specifying lifestyle and food habits. Body composition was determined using the impedancemetry and D2O technique.
RESULTS
The results showed a difference between the percentage of obese and overweight children according to BMIZ classification (30.1%), bioelectrical impedance method (14.7%) and DO technique (42.9%). Despite the difference between the last two classifications, we found a significant correlation between body fat percentages determined by impedancemetry and DO technique (r = 0.695, p<0.01). Bioelectrical impedance analysis underestimated %BF by 78.02% in overall children, by 70.05% in boys and by 84.73% in girls compared to DO technique.
CONCLUSION
This study has demonstrated that the percentage of overweight and obesity varied according the methods used. Further development of body composition methods is needed in children for the real determination of the obesity prevalence and therefore a better monitoring of this public health problem.
Topics: Male; Female; Child; Humans; Body Mass Index; Deuterium; Overweight; Adipose Tissue; Body Composition; Obesity
PubMed: 38357184
DOI: 10.4314/ahs.v23i3.77 -
European Journal of Nutrition Jun 2024Rapid gastric emptying and intestinal absorption of beverages is essential for rapid rehydration, and certain amino acids (AA) may augment fluid delivery. Three... (Randomized Controlled Trial)
Randomized Controlled Trial
PURPOSE
Rapid gastric emptying and intestinal absorption of beverages is essential for rapid rehydration, and certain amino acids (AA) may augment fluid delivery. Three sugar-free beverages, containing differing AA concentrations (AA + PZ), were assessed for fluid absorption kinetics against commercial sugar-free (PZ, GZ) and carbohydrate-containing (GTQ) beverages.
METHODS
Healthy individuals (n = 15-17 per study) completed three randomised trials. Three beverages (550-600 mL) were ingested in each study (Study 1: AA + PZ [17.51 g/L AA], PZ, GZ; Study 2: AA + PZ [6.96 g/L AA], PZ, GZ; Study 3: AA + PZ [3.48 g/L AA], PZ, GTQ), containing 3.000 g deuterium oxide (DO). Blood samples were collected pre-, 2-min, 5-min, and every 5-min until 60-min post-ingestion to quantify maximal DO enrichment (Cmax), time Cmax occurred (Tmax) and area under the curve (AUC).
RESULTS
Study 1: AUC (AA + PZ: 15,184 ± 3532 δ‰ vs. VSMOW; PZ: 17,328 ± 3153 δ‰ vs. VSMOW; GZ: 17,749 ± 4204 δ‰ vs. VSMOW; P ≤ 0.006) and Tmax (P ≤ 0.005) were lower for AA + PZ vs. PZ/GZ. Study 2: DO enrichment characteristics were not different amongst beverages (P ≥ 0.338). Study 3: Cmax (AA + PZ: 440 ± 94 δ‰ vs. VSMOW; PZ: 429 ± 83 δ‰ vs. VSMOW; GTQ: 398 ± 81 δ‰ vs. VSMOW) was greater (P = 0.046) for AA + PZ than GTQ, with no other differences (P ≥ 0.106).
CONCLUSION
The addition of small amounts of AA (3.48 g/L) to a sugar-free beverage increased fluid delivery to the circulation compared to a carbohydrate-based beverage, but greater amounts (17.51 g/L) delayed delivery.
Topics: Humans; Beverages; Amino Acids; Male; Adult; Female; Young Adult; Fluid Therapy; Water; Cross-Over Studies; Gastric Emptying; Kinetics; Rehydration Solutions; Sports Nutritional Physiological Phenomena; Intestinal Absorption
PubMed: 38349552
DOI: 10.1007/s00394-024-03325-x -
Applied Radiation and Isotopes :... Apr 2024The possibility of creating technical means for controlling the processes of accumulation and conversion of the energies of thermal and epithermal neutrons into the...
The possibility of creating technical means for controlling the processes of accumulation and conversion of the energies of thermal and epithermal neutrons into the energy of monoenergetic photons due to neutron pumping of an active medium consisting of nuclei with long-lived isomeric states was studied in this work. The system under study consisted of an external pulse-periodic source of deuterium-tritium neutrons (PSN) and a subcritical blanket, which included a variable neutron-collimation beam-shaping assembly (vBSA) and an active medium. The vBSA was composed of moderating blocks and selective plates designed to trap and shape a pulsed neutron flux with subsequent conversion of a millisecond signature into monoenergetic photon emission. Gadolinium oxide enriched in Gd isotope was used as the active medium, where the heavier one could be at different excited states, the de-excitations of which were accompanied by photon emission. In this research, the possibility of using the conjugate system (i.e., blanket - PSN - vBSA) for converting excess neutron energy accumulated in the inverse state of Gd nuclei into photon emission was demonstrated in detail.
PubMed: 38346373
DOI: 10.1016/j.apradiso.2024.111232 -
Journal of Cachexia, Sarcopenia and... Apr 2024Bed-rest (BR) of only a few days duration reduces muscle protein synthesis and induces skeletal muscle atrophy and insulin resistance, but the scale and juxtaposition of...
BACKGROUND
Bed-rest (BR) of only a few days duration reduces muscle protein synthesis and induces skeletal muscle atrophy and insulin resistance, but the scale and juxtaposition of these events have not been investigated concurrently in the same individuals. Moreover, the impact of short-term exercise-supplemented remobilization (ESR) on muscle volume, protein turnover and leg glucose uptake (LGU) in humans is unknown.
METHODS
Ten healthy males (24 ± 1 years, body mass index 22.7 ± 0.6 kg/m) underwent 3 days of BR, followed immediately by 3 days of ESR consisting of 5 × 30 maximal voluntary single-leg isokinetic knee extensions at 90°/s each day. An isoenergetic diet was maintained throughout the study (30% fat, 15% protein and 55% carbohydrate). Resting LGU was calculated from arterialized-venous versus venous difference across the leg and leg blood flow during the steady-state of a 3-h hyperinsulinaemic-euglycaemic clamp (60 mU/m/min) measured before BR, after BR and after remobilization. Glycogen content was measured in vastus lateralis muscle biopsy samples obtained before and after each clamp. Leg muscle volume (LMV) was measured using magnetic resonance imaging before BR, after BR and after remobilization. Cumulative myofibrillar protein fractional synthetic rate (FSR) and whole-body muscle protein breakdown (MPB) were measured over the course of BR and remobilization using deuterium oxide and 3-methylhistidine stable isotope tracers that were administered orally.
RESULTS
Compared with before BR, there was a 45% decline in insulin-stimulated LGU (P < 0.05) after BR, which was paralleled by a reduction in insulin-stimulated leg blood flow (P < 0.01) and removal of insulin-stimulated muscle glycogen storage. These events were accompanied by a 43% reduction in myofibrillar protein FSR (P < 0.05) and a 2.5% decrease in LMV (P < 0.01) during BR, along with a 30% decline in whole-body MPB after 2 days of BR (P < 0.05). Myofibrillar protein FSR and LMV were restored by 3 days of ESR (P < 0.01 and P < 0.01, respectively) but not by ambulation alone. However, insulin-stimulated LGU and muscle glycogen storage were not restored by ESR.
CONCLUSIONS
Three days of BR caused concurrent reductions in LMV, myofibrillar protein FSR, myofibrillar protein breakdown and insulin-stimulated LGU, leg blood flow and muscle glycogen storage in healthy, young volunteers. Resistance ESR restored LMV and myofibrillar protein FSR, but LGU and muscle glycogen storage remained depressed, highlighting divergences in muscle fuel and protein metabolism. Furthermore, ambulation alone did not restore LMV and myofibrillar protein FSR in the non-exercised contralateral limb, emphasizing the importance of exercise rehabilitation following even short-term BR.
Topics: Male; Humans; Glucose; Muscle, Skeletal; Insulin; Glycogen; Muscle Proteins
PubMed: 38343303
DOI: 10.1002/jcsm.13431 -
Molecules (Basel, Switzerland) Jan 2024Radical reactions in water or aqueous media are important for organic synthesis, realizing high-yielding processes under non-toxic and environmentally friendly... (Review)
Review
Radical reactions in water or aqueous media are important for organic synthesis, realizing high-yielding processes under non-toxic and environmentally friendly conditions. This overview includes (i) a general introduction to organic chemistry in water and aqueous media, (ii) synthetic approaches in, on, and with water as well as in heterogeneous phases, (iii) reactions of carbon-centered radicals with water (or deuterium oxide) activated through coordination with various Lewis acids, (iv) photocatalysis in water and aqueous media, and (v) synthetic applications bioinspired by naturally occurring processes. A wide range of chemical processes and synthetic strategies under different experimental conditions have been reviewed that lead to important functional group translocation and transformation reactions, leading to the preparation of complex molecules. These results reveal how water as a solvent/medium/reagent in radical chemistry has matured over the last two decades, with further discoveries anticipated in the near future.
PubMed: 38338314
DOI: 10.3390/molecules29030569 -
Heliyon Jan 2024Carbon sequestration is one approach to achieve carbon dioxide reduction in the atmosphere. Underground storage of CO requires an understanding of geochemical and...
Carbon sequestration is one approach to achieve carbon dioxide reduction in the atmosphere. Underground storage of CO requires an understanding of geochemical and geomechanical alteration on the integrity of the injection wellbore. In this study, we investigate the reactivity of supercritical CO (scCO) at 65 °C and 20.7 MPa on Portland class G cement plugs used for oil and gas well completion, for exposure of up to 5 weeks. For nanoporous media, such as cement, diffusion is believed to be the major mass transport mechanism (Perkins and Johnston, 1963) [1]. To quantify the extent of the alteration (mineralization/dissolution) on fluid diffusivity through the cement matrix, a novel approach based on Nuclear Magnetic Resonance (NMR) is employed to derive diffusional tortuosity. Comparing pre- and post-scCO exposure, deuterium oxide (DO) intrusion profiles allow us to determine flow path alteration in the cement plugs. Additional characterizations include Fourier Transform Infrared Spectroscopy (FTIR) to observe the change in cement composition, micro X-ray Computed Tomography (μXCT), along with Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) to determine invasion extent and microstructure modifications, Mercury Injection Capillary Pressure (MICP) for pore throat size distribution and BET N isothermal adsorption for surface area and pore size distribution. The results show that exposure to scCO promotes both calcium carbonate precipitation and dissolution simultaneously. However, the alteration is pore size dependent. After 5 weeks of exposure, there is evidence of carbonate dissolution in smaller pores (<30 nm) and both precipitation and dissolution in larger pores (30-200 nm). The alteration of the cement plugs leads to a decrease in the storage and connectivity of the cement. The porosity decreased from 37 to 33 % in 5 weeks, while the matrix tortuosity increased by 6 and 3 times after 2 and 5 weeks of exposure, respectively. The experimental results imply that the cement carbonate precipitation can limit the migration of scCO through the cement matrix. This work also highlights an alternative laboratory approach to quantify the risk associated with scCO exposure on Portland cement using NMR-derived tortuosity.
PubMed: 38312658
DOI: 10.1016/j.heliyon.2024.e24144 -
BMC Chemistry Jan 2024Quantitative H-NMR became an increasingly important issue in pharmaceutical analytical chemistry. This study used NMR spectroscopy to assay the bronchodilator drug...
Quantitative H-NMR became an increasingly important issue in pharmaceutical analytical chemistry. This study used NMR spectroscopy to assay the bronchodilator drug terbutaline sulfate and its pro-drug bambuterol hydrochloride in pure form and pharmaceutical preparations. The technique proceeded using deuterium oxide (DO) as an H-NMR solvent and phloroglucinol anhydrous as an internal standard (IS). Comparatively, to the phloroglucinol signal at 5.9 ppm, the resulting quantitative signals of the studied drugs were corrected. The terbutaline singlet signal at 6.3 ppm was chosen for quantification, while the bambuterol quantitative singlet signal was at 2.9 ppm. The two drugs were rectilinear over the concentration range of 1.0-16.0 mg/mL. LOD values were 0.19 and 0.21 mg/mL while LOQ values were 0.58 and 0.64 mg/mL for terbutaline and bambuterol respectively. The developed method has been validated according to the International Conference of Harmonization (ICH) regarding linearity, accuracy, precision, specificity, and robustness. A greenness profile assessment was applied, and the method proved to be green. The method enables the assay of the two drugs in pure drug and pharmaceutical preparations. The method also enables the assay of the two drugs in the presence of each other; thus, it is considered a stability-indicating method where terbutaline is an acid degradation product of bambuterol.
PubMed: 38291471
DOI: 10.1186/s13065-024-01120-7