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International Journal of Molecular... Aug 2022One of the commonly accepted approaches to estimate protein-protein interactions (PPI) in aqueous solutions is the analysis of their translational diffusion. The present... (Review)
Review
One of the commonly accepted approaches to estimate protein-protein interactions (PPI) in aqueous solutions is the analysis of their translational diffusion. The present review article observes a phenomenological approach to analyze PPI effects via concentration dependencies of self- and collective translational diffusion coefficient for several spheroidal proteins derived from the pulsed field gradient NMR (PFG NMR) and dynamic light scattering (DLS), respectively. These proteins are rigid globular α-chymotrypsin (ChTr) and human serum albumin (HSA), and partly disordered α-casein (α-CN) and β-lactoglobulin (β-Lg). The PPI analysis enabled us to reveal the dominance of intermolecular repulsion at low ionic strength of solution (0.003-0.01 M) for all studied proteins. The increase in the ionic strength to 0.1-1.0 M leads to the screening of protein charges, resulting in the decrease of the protein electrostatic potential. The increase of the van der Waals potential for ChTr and α-CN characterizes their propensity towards unstable weak attractive interactions. The decrease of van der Waals interactions for β-Lg is probably associated with the formation of stable oligomers by this protein. The PPI, estimated with the help of interaction potential and idealized spherical molecular geometry, are in good agreement with experimental data.
Topics: Biophysical Phenomena; Caseins; Diffusion; Humans; Osmolar Concentration; Protein Processing, Post-Translational; Static Electricity
PubMed: 36012504
DOI: 10.3390/ijms23169240 -
Current Diabetes Reviews 2018Although hypovolemia remains the most relevant problem during acute decompensated diabetes in its clinical manifestations (diabetic ketoacidosis, DKA, and hyperglycemic... (Review)
Review
INTRODUCTION
Although hypovolemia remains the most relevant problem during acute decompensated diabetes in its clinical manifestations (diabetic ketoacidosis, DKA, and hyperglycemic hyperosmolar state, HHS), the electrolyte derangements caused by the global hydroelectrolytic imbalance usually complicate the clinical picture at presentation and may be worsened by the treatment itself.
AIM
This review article is focused on the management of dysnatremias during hyperglycemic hyperosmolar state with the aim of providing clinicians a useful tool to early identify the sodium derangement in order to address properly its treatment.
DISCUSSION
The plasma sodium concentration is modified by most of the therapeutic measures commonly required in such patients and the physician needs to consider these interactions when treating HHS. Moreover, an improper management of plasma sodium concentration (PNa+) and plasma osmolality during treatment has been associated with two rare potentially life-threatening complications (cerebral edema and osmotic demyelination syndrome). Identifying the correct composition of the fluids that need to be infused to restore volume losses is crucial to prevent complications.
CONCLUSION
A quantitative approach based on the comparison between the measured PNa+ (PNa+ M) and the PNa+ expected in the presence of an exclusive water shift (PNa+ G) may provide more thorough information about the true hydroelectrolytic status of the patient and may therefore, guide the physician in the initial management of HHS. On the basis of data derived from our previous studies, we propose a 7-step algorithm to compute an accurate estimate of PNa+ G.
Topics: Brain Edema; Fluid Therapy; Humans; Hyperglycemic Hyperosmolar Nonketotic Coma; Hypernatremia; Hyponatremia; Hypovolemia; Osmolar Concentration; Sodium
PubMed: 29557753
DOI: 10.2174/1573399814666180320091451 -
Cardiorenal Medicine 2022Determination of adequacy of decongestion remains a significant challenge in the management of acute heart failure (AHF).
BACKGROUND
Determination of adequacy of decongestion remains a significant challenge in the management of acute heart failure (AHF).
METHODS
This is a prospective single center cohort study of patients (>18 years old) admitted for AHF on intravenous diuretics, with BNP >100 pg/mL or echocardiographic findings of reduced ejection fraction or diastolic dysfunction, and at least 1 clinical sign of volume overload. Patients with eGFR ≤45 mL/min or on dialysis, and with exposure to contrast dye or nephrotoxins were excluded. Serum and spot urine osmolality were obtained in the early morning simultaneously daily for 5 days or until discharge. Receiver operating characteristic curves were used to analyze the optimal cutoffs for the osmolality values in the prediction of heart failure (HF) readmissions Results: Of the total 100 patients, 62% were male and 59% were Black American. The mean age was 64.41 ± 12.53 and 34% had preserved ejection fraction. Patients with 30-day readmission had higher serum osmolality (mOsm/kg) on admission (305 [299-310] vs. 298 [294-303]; p = 0.044) and had higher drop in serum osmolality between admission and discharge (-7.5 [-9.0, -1.25] vs. -1.0 [-4.0, 4.0]; p = 0.044). Serum osmolality on admission of >299 mOsm/kg (sensitivity: 83%, specificity: 61%) and drop in serum osmolality between admission and discharge of >2 mOsm/kg (sensitivity: 83%, specificity: 65%) was associated with 30-day HF readmissions. No patients discharged with urine osmolality more than 500 mOsm/kg had 30-day readmissions, but this was not statistically significant, p = 0.334.
CONCLUSION
Measurement of serum osmolality and urine osmolality may have some utility in AHF, but interpretation should consider baseline values and dynamic changes to account for individual differences in sodium and water handling.
Topics: Male; Humans; Middle Aged; Aged; Adolescent; Female; Prospective Studies; Cohort Studies; Heart Failure; Diuresis; Osmolar Concentration
PubMed: 35760046
DOI: 10.1159/000525730 -
Journal of Biological Physics Jun 2022Changes in the osmolality of the extracellular medium (ECM) affect cell volume and cellular processes such as cell migration and proliferation. Not only may high...
Changes in the osmolality of the extracellular medium (ECM) affect cell volume and cellular processes such as cell migration and proliferation. Not only may high concentrations of zinc (Zn) lead to cell death by apoptosis, but Zn is also a physiological suppressor of apoptosis. The aim of our study was to examine whether Zn and regulation of extracellular osmolality had an effect on the lung cancer cell line (A549) and how to be changed in ECM according to elements and osmolality depending on incubation time and Zn application. Our study consisted of four groups: cell-free medium, ECM of cancer cell after 24 h incubation (24hECM), ECM of cancer cell after 48 h incubation (48hECM), and ECM of cancer cell after 48 h incubation with ZnCl (48hECM + Zn). ECM osmolality was measured by using osmometer, and the levels of chromium (Cr), iron (Fe), and magnesium (Mg) elements were analyzed using ICP-OES device for all groups. According to the result of the analysis, a statistically significant difference was found when osmolality and element values of ECM of 24hECM and 48hECM groups were compared with the values of the 48hECM + Zn group. It was observed that there was a decrease in the levels of Cr, Fe, and Mg with Zn application and incubation period in ECM. The regulation of ECM osmolality is a promising method due to biophysical effects on cancer cells. In our study, we speculated that the understanding of the effects of Zn and osmolality with the relationship between ECM and cancer cell might lead to the discovery of biophysical approaches as a novel therapeutic strategy.
Topics: Culture Media; Iron; Magnesium; Neoplasms; Osmolar Concentration; Zinc
PubMed: 35325363
DOI: 10.1007/s10867-022-09604-0 -
European Cells & Materials Nov 2018Intervertebral disc (IVD) cells are naturally exposed to high osmolarity and complex mechanical loading, which drive microenvironmental osmotic changes. Age- and... (Review)
Review
Intervertebral disc (IVD) cells are naturally exposed to high osmolarity and complex mechanical loading, which drive microenvironmental osmotic changes. Age- and degeneration-induced degradation of the IVD's extracellular matrix causes osmotic imbalance, which, together with an altered function of cellular receptors and signalling pathways, instigates local osmotic stress. Cellular responses to osmotic stress include osmoadaptation and activation of pro-inflammatory pathways. This review summarises the current knowledge on how IVD cells sense local osmotic changes and translate these signals into physiological or pathophysiological responses, with a focus on inflammation. Furthermore, it discusses the expression and function of putative membrane osmosensors (e.g. solute carrier transporters, transient receptor potential channels, aquaporins and acid-sensing ion channels) and osmosignalling mediators [e.g. tonicity response-element-binding protein/nuclear factor of activated T-cells 5 (TonEBP/NFAT5), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB)] in healthy and degenerated IVDs. Finally, an overview of the potential therapeutic targets for modifying osmosensing and osmosignalling in degenerated IVDs is provided.
Topics: Animals; Humans; Inflammation; Intervertebral Disc; Osmolar Concentration; Osmoregulation; Osmosis; Signal Transduction
PubMed: 30452080
DOI: 10.22203/eCM.v036a17 -
Nutrients Jan 2022The body's water and sodium balances are tightly regulated and monitored by the brain. Few studies have explored the relationship between water and salt intake, and...
The body's water and sodium balances are tightly regulated and monitored by the brain. Few studies have explored the relationship between water and salt intake, and whether sodium intake with different levels of fluid intake leads to changes in hydration status remains unknown. The aim of the present study was to determine the patterns of water intake and hydration status among young adults with different levels of daily salt intakes. Participants' total drinking fluids and water from food were determined by a 7-day 24-h fluid intake questionnaire for 7 days (from Day 1 to Day 7) and duplicate portion method (Day 5, Day 6 and Day 7). Urine of 24 h for 3 days (Day 5, Day 6 and Day 7) was collected and tested for the osmolality, the urine-specific gravity (USG), the concentrations of electrolytes, pH, creatinine, uric acid and the urea. The fasting blood samples for 1 day (Day 6) were collected and measured for the osmolality and the concentrations of electrolytes. The salt intakes of the participants were evaluated from the concentrations of Na of 24 h urine of 3 days (Day 5, Day 6 and Day 7). Participants were divided into four groups according to the quartile of salt intake, including the low salt intake (LS), LS, high salt intake (HS) and HS groups. In total, 156 participants (including 80 male and 76 female young adults) completed the study. The salt intakes were 7.6, 10.9, 14.7 and 22.4 g among participants in the four groups (LS, LS, HS and HS groups, respectively), which differed significantly in all groups ( = 252.020; all < 0.05). Compared to the LS and LS groups, the HS group had 310-381, 250-358 and 382-655 mL more amounts of water from the total water intake (TWI), total drinking fluids and water from food (all < 0.05), respectively. Participants in the HS group had 384-403, 129-228 and 81-114 mL more in the water, water from dishes and staple foods, respectively, than those in the groups of LS and LS ( < 0.05). The HS group excreted 386-793 mL more urine than those in the groups of LS and LS ( < 0.05). However, regarding urine osmolality, the percentage of participants with optimal hydration status decreased from 41.0% in LS and LS to 25.6% in the HS group ( 0.05). Participants with higher salt intake had higher TWI, total drinking fluids and water from food. Nevertheless, they had inferior hydration status. A reduction in salt intake should be encouraged among young adults to maintain optimal hydration status.
Topics: Cross-Sectional Studies; Diet; Diet Surveys; Drinking; Female; Humans; Male; Organism Hydration Status; Osmolar Concentration; Sodium; Sodium Chloride, Dietary; Specific Gravity; Surveys and Questionnaires; Urinalysis; Young Adult
PubMed: 35057468
DOI: 10.3390/nu14020287 -
International Journal of Environmental... May 2022The aim of this study was to determine the effects of different seasons of the year and the time of day (before work vs. after work) on hydration status in men. The...
The aim of this study was to determine the effects of different seasons of the year and the time of day (before work vs. after work) on hydration status in men. The study involved sixty foresters who spent most of the work outdoors. During three seasons of the year (summer, autumn, and winter), indices of hydration status (body mass (BM) and percentage change of BM, total body water (TBW) and percentage change of TBW, serum osmolality (Sosm) and percentage change of Sosm, urine osmolality, urine-specific gravity (USG), urine color, and thirst) were determined before work on the first day (time point 1 used as baseline), immediately after work on the first day (time point 2), and before work on the following day (time point 3). USG decreased at time point 2 compared to time point 1 (p < 0.001) and time point 3 (p = 0.03). At time point 2 (p = 0.002) in winter and time point 3 in autumn (p = 0.049), serum osmolality was higher than in summer. In conclusion, the differences in hydration status depended on the time of day and season. A large percentage of foresters come to work inadequately hydrated, especially in colder seasons compared to summer.
Topics: Dehydration; Humans; Male; Osmolar Concentration; Pilot Projects; Thirst; Urinalysis
PubMed: 35565019
DOI: 10.3390/ijerph19095627 -
Microbiology (Reading, England) Aug 2019L form bacteria do not have a cell wall and are thought to require medium of high osmolality for survival and growth. In this study we tested whether L forms can adapt...
L form bacteria do not have a cell wall and are thought to require medium of high osmolality for survival and growth. In this study we tested whether L forms can adapt to growth in lower osmolality medium. We first tested the Escherichia coli L form NC-7, generated in 1987 by Onoda following heavy mutagenesis. We started with growth in osmoprotective medium (~ 764 mOsm kg) and diluted it stepwise into medium of lower osmolality. At each step the cells were given up to 10 days to adapt and begin growing, during which they apparently acquired multiple new mutations. We eventually obtained a strain that could grow in LB containing only 34 mM NaCl, 137 mOsm kg total. NC-7 showed a variety of morphologies including spherical, angular and cylindrical cells. Some cells extruded a bud that appeared to be the outer membrane enclosing an enlarged periplasm. Additional evidence for an outer membrane was sensitivity of the cells to the compound CHIR-090, which blocks the LPS pathway, and to EDTA which chelates Mg that may stabilize and rigidify the LPS in the outer membrane. We suggest that the mechanical rigidity of the outer membrane enables the angular shapes and provides some resistance to turgor in the low-osmolality media. Interestingly, cells that had an elongated shape underwent division shortly after addition of EDTA, suggesting that reducing the rigidity of the outer membrane under some turgor pressure induces division before lysis occurs. We then tested a well-characterized L form from Bacillus subtilis. L form strain LR-2L grew well with sucrose at 1246 and 791 mOsm kg. It survived when diluted directly into 440 mOsm kg but grew poorly, achieving only 1/10 to 1/5 the density. The B. subtilis L form apparently adapted to this direct dilution by rapidly reducing cytoplasmic osmolality.
Topics: Bacillus subtilis; Cell Culture Techniques; Escherichia coli; L Forms; Osmolar Concentration
PubMed: 30958258
DOI: 10.1099/mic.0.000799 -
American Journal of Physiology. Renal... Dec 2015
Review
Topics: Animals; Fluorescent Antibody Technique; Humans; Kidney; Kidney Diseases; Osmolar Concentration; Rats; Space Flight
PubMed: 26400547
DOI: 10.1152/ajprenal.00418.2015 -
Scientific Reports Nov 2023In euryhaline fish, prolactin (Prl) plays an essential role in freshwater (FW) acclimation. In the euryhaline and eurythermal Mozambique tilapia, Oreochromis...
In euryhaline fish, prolactin (Prl) plays an essential role in freshwater (FW) acclimation. In the euryhaline and eurythermal Mozambique tilapia, Oreochromis mossambicus, Prl cells are model osmoreceptors, recently described to be thermosensitive. To investigate the effects of temperature on osmoreception, we incubated Prl cells of tilapia acclimated to either FW or seawater (SW) in different combinations of temperatures (20, 26 and 32 °C) and osmolalities (280, 330 and 420 mOsm/kg) for 6 h. Release of both Prl isoforms, Prl and Prl, increased in hyposmotic media and were further augmented with a rise in temperature. Hyposmotically-induced release of Prl, but not Prl, was suppressed at 20 °C. In SW fish, mRNA expression of prl increased with rising temperatures at lower osmolalities, while and prl decreased at 32 °C and higher osmolalities. In Prl cells of SW-acclimated tilapia incubated in hyperosmotic media, the expressions of Prl receptors, prlr1 and prlr2, and the stretch-activated Ca channel, trpv4,decreased at 32 °C, suggesting the presence of a cellular mechanism to compensate for elevated Prl release. Transcription factors, pou1f1, pou2f1b, creb3l1, cebpb, stat3, stat1a and nfat1c, known to regulate prl and prl, were also downregulated at 32 °C. Our findings provide evidence that osmoreception is modulated by temperature, and that both thermal and osmotic responses vary with acclimation salinity.
Topics: Animals; Prolactin; Tilapia; Temperature; Receptors, Prolactin; Osmolar Concentration
PubMed: 37980366
DOI: 10.1038/s41598-023-47044-5