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Biomolecules Jun 2022Interactions between physical forces and membrane proteins underpin many forms of environmental sensation and acclimation. Microbes survive osmotic stresses with the...
Interactions between physical forces and membrane proteins underpin many forms of environmental sensation and acclimation. Microbes survive osmotic stresses with the help of mechanically gated ion channels and osmolyte transporters. Plant mechanosensitive ion channels have been shown to function in defense signaling. Here, we engineered genetically encoded osmolality sensors (OzTracs) by fusing fluorescent protein spectral variants to the mechanosensitive ion channels MscL from or MSL10 from . When expressed in yeast cells, the OzTrac sensors reported osmolality changes as a proportional change in the emission ratio of the two fluorescent protein domains. Live-cell imaging revealed an accumulation of fluorescent sensors in internal aggregates, presumably derived from the endomembrane system. Thus, OzTrac sensors serve as osmolality-dependent reporters through an indirect mechanism, such as effects on molecular crowding or fluorophore solvation.
Topics: Arabidopsis; Arabidopsis Proteins; Escherichia coli; Escherichia coli Proteins; Ion Channels; Membrane Proteins; Osmolar Concentration; Osmotic Pressure
PubMed: 35740912
DOI: 10.3390/biom12060787 -
Molecular Cell Sep 2020In this issue of Molecular Cell, Jalihal et al. (2020) show that cell volume changes upon osmotic stress result in rapid and reversible condensation of numerous...
In this issue of Molecular Cell, Jalihal et al. (2020) show that cell volume changes upon osmotic stress result in rapid and reversible condensation of numerous multivalent proteins.
Topics: Cell Size; Osmotic Pressure; Proteins
PubMed: 32946761
DOI: 10.1016/j.molcel.2020.09.001 -
Korean Journal of Radiology Oct 2020To evaluate the incidence and risk factors of emetic complications associated with the intravenous administration of low-osmolality iodinated contrast media (ICM) in...
OBJECTIVE
To evaluate the incidence and risk factors of emetic complications associated with the intravenous administration of low-osmolality iodinated contrast media (ICM) in children undergoing computed tomography (CT).
MATERIALS AND METHODS
All children who underwent contrast-enhanced CT between April 2017 and July 2019 were included. Pediatric patients were instructed on the preparative dietary protocol at our institution. Experienced nurses in the radiology department monitored the children during the CT scans and recorded any emetic complications in their electronic medical records. These data were used to calculate the incidence of emetic complications. Various patient factors and technical factors, including fasting duration, the type and volume of ICM, and ongoing chemotherapy, were evaluated to identify risk factors for emetic complications using univariate and multivariate logistic regression analyses.
RESULTS
Among the 864 children (mean age, 8.4 ± 5.7 years) evaluated, 18 (2.1%) experienced emetic complications (6 experienced nausea only and 12 experienced nausea and vomiting). None of the children developed aspiration pneumonia. The mean fasting duration of patients with emesis was 7.9 ± 5.7 hours (range, 3-21 hours), whereas that of patients without nausea was 8.7 ± 5.7 hours (range, 0-24 hours). Fasting duration was not associated with the development of nausea and vomiting ( = 0.634). Multivariate logistic regression analysis revealed that ongoing chemotherapy (odds ratio [OR] = 4.323; 95% confidence interval [CI] = 1.430-13.064; = 0.009), iomeprol use (OR = 7.219; 95% CI = 1.442-36.146; = 0.016), and iohexol use (OR = 5.241; 95% CI = 1.350-20.346; = 0.017) were independent risk factors for emetic complications.
CONCLUSION
Only a small proportion (2.1%) of children experienced nausea or vomiting after exposure to low-osmolality ICM. Many children underwent excessive fasting; however, fasting duration was not associated with nausea and vomiting. Moreover, ongoing chemotherapy and the use of iomeprol or iohexol were identified as potential risk factors for emetic complications in children.
Topics: Adolescent; Child; Child, Preschool; Contrast Media; Fasting; Female; Humans; Incidence; Infant; Infant, Newborn; Logistic Models; Male; Nausea; Odds Ratio; Osmolar Concentration; Risk Factors; Tomography, X-Ray Computed; Vomiting; Young Adult
PubMed: 32767861
DOI: 10.3348/kjr.2019.0835 -
ELife Sep 2021Water balance, tracked by extracellular osmolality, is regulated by feedback and feedforward mechanisms. Feedback regulation is reactive, occurring as deviations in...
Water balance, tracked by extracellular osmolality, is regulated by feedback and feedforward mechanisms. Feedback regulation is reactive, occurring as deviations in osmolality are . Feedforward or presystemic regulation is proactive, occurring when disturbances in osmolality are . Vasopressin (AVP) is a key hormone regulating water balance and is released during hyperosmolality to limit renal water excretion. AVP neurons are under feedback and feedforward regulation. Not only do they respond to disturbances in blood osmolality, but they are also rapidly suppressed and stimulated, respectively, by drinking and eating, which will ultimately decrease and increase osmolality. Here, we demonstrate that AVP neuron activity is regulated by multiple anatomically and functionally distinct neural circuits. Notably, presystemic regulation during drinking and eating are mediated by non-overlapping circuits that involve the lamina terminalis and hypothalamic arcuate nucleus, respectively. These findings reveal neural mechanisms that support differential regulation of AVP release by diverse behavioral and physiological stimuli.
Topics: Animals; Arginine Vasopressin; Female; Hypothalamus; Male; Mice; Neurons; Osmolar Concentration; Osmotic Pressure; Vasopressins; Water-Electrolyte Balance
PubMed: 34585668
DOI: 10.7554/eLife.66609 -
Journal of Assisted Reproduction and... Aug 2019To investigate the stability of osmolality in non-humidified and humidified incubators for assisted reproductive technologies (ART).
PURPOSE
To investigate the stability of osmolality in non-humidified and humidified incubators for assisted reproductive technologies (ART).
METHODS
Drops of three single-step culture media (media A, B, and C) were incubated for 5 or 6 days covered with four different mineral oils (oils A, B, C, and D) in non-humidified incubator A, non-humidified incubator B, or humidified incubator C to investigate the effects of incubator environment (humidification), drop volume, culture media, and mineral oil on the stability of osmolality in microdrops.
RESULTS
A significant and linear increase was shown in the osmolality of 50-μL and 200-μL microdrops covered with mineral oil during 5 days incubation in non-humidified benchtop incubators. The maximum increase was 20 mOsm/kg, and the extent of the increase was affected by microdrop volume and possibly by the type of mineral oil used to cover the drops. In contrast, the osmolality of 50-μL and 200-μL microdrops did not change during 5 days incubation in a humidified benchtop incubator.
CONCLUSIONS
Mineral oil alone may not adequately prevent gradual changes in the osmolality of low-volume microdrops during extended in vitro culture of human embryos in non-humidified incubators. As a result, the osmolality may increase to high enough levels to stress some human embryos and adversely affect clinical outcomes. We therefore recommend that the stability of osmolality should be given more consideration to ensure optimal culture conditions for ART.
Topics: Culture Media; Embryo Culture Techniques; Embryo, Mammalian; Embryonic Development; Female; Fertilization in Vitro; Humans; Humidity; Incubators; Mineral Oil; Osmolar Concentration
PubMed: 31267335
DOI: 10.1007/s10815-019-01515-9 -
Comparative Biochemistry and... Jun 2022For amphibian species that display external fertilization in an aquatic environment, hypoosmotic shock to sperm cells can quickly result in damage to cellular structure...
For amphibian species that display external fertilization in an aquatic environment, hypoosmotic shock to sperm cells can quickly result in damage to cellular structure and function. This study sought to determine how fertilization media osmolality, temperature, and time impact the stability of the mitochondrial vesicle's association with the sperm head and thus motility and quality of forward progression. The presence of the mitochondrial vesicle and its relationship with sperm motility and quality of forward progression were analyzed in sperm samples from the Fowler's toad (Anaxyrus fowleri) (n = 10) when held for six hours under two temperatures and four osmolalities. Results indicated that the presence of the mitochondrial vesicle is needed for sperm motility over time (p < 0.001), where higher osmolalities (p < 0.001) and lower temperatures (p < 0.001) correlated with maintaining the vesicle attachment to the spermatozoa. The higher osmolality of spermic urine was the most important factor for maintaining higher quality of forward progressive motility (p < 0.01) of spermatozoa. Sperm samples held at 4 °C and 40 mOsm/kg had the longest half-life for motility (540 min) and quality of forward progression (276 min), whereas sperm held at 22 °C and 2.5 mOsm/kg had the shortest half-life for motility (7 min) and quality of forward progression (18 min). Special attention should be given to the osmolality and temperature of fertilization solutions, or breeding tank water, when developing cold storage protocols for toad sperm or reproducing animals to ensure the retention of the mitochondrial vesicle for maximum fertilization capability.
Topics: Animals; Bufonidae; Cryopreservation; Male; Osmolar Concentration; Sperm Motility; Spermatozoa
PubMed: 35321851
DOI: 10.1016/j.cbpa.2022.111191 -
Neuron Jul 2019For thirsty animals, fluid intake provides both satiation and pleasure of drinking. How the brain processes these factors is currently unknown. Here, we identified...
For thirsty animals, fluid intake provides both satiation and pleasure of drinking. How the brain processes these factors is currently unknown. Here, we identified neural circuits underlying thirst satiation and examined their contribution to reward signals. We show that thirst-driving neurons receive temporally distinct satiation signals by liquid-gulping-induced oropharyngeal stimuli and gut osmolality sensing. We demonstrate that individual thirst satiation signals are mediated by anatomically distinct inhibitory neural circuits in the lamina terminalis. Moreover, we used an ultrafast dopamine (DA) sensor to examine whether thirst satiation itself stimulates the reward-related circuits. Interestingly, spontaneous drinking behavior but not thirst drive reduction triggered DA release. Importantly, chemogenetic stimulation of thirst satiation neurons did not activate DA neurons under water-restricted conditions. Together, this study dissected the thirst satiation circuit, the activity of which is functionally separable from reward-related brain activity.
Topics: Animals; Calcium; Dopamine; Drinking; Female; GABAergic Neurons; Glucagon-Like Peptide 1; Luminescent Proteins; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Nerve Net; Neural Pathways; Nitric Oxide Synthase Type I; Optogenetics; Osmolar Concentration; Peptide Fragments; Physical Stimulation; Satiation; Stomach; Subfornical Organ
PubMed: 31153646
DOI: 10.1016/j.neuron.2019.04.039 -
European Journal of Sport Science Apr 2023The present study aimed to test the hypothesis that changes in the dermal tissue dielectric constant (TDC) and biomechanical properties of the skin would be correlated... (Randomized Controlled Trial)
Randomized Controlled Trial
The present study aimed to test the hypothesis that changes in the dermal tissue dielectric constant (TDC) and biomechanical properties of the skin would be correlated with the indicators related to dehydration. Ten healthy adult men were enrolled in three trials: no fluid intake (DEH), fluid intake (AL-HYD), and programmed fluid intake (P-HYD) after exercise in a randomised crossover design. The participants performed a pedalling exercise at 60% heart rate reserve until 2% body mass loss. At 120 min after exercise, an incremental exercise test was carried out. Aerobic capacity, body composition, TDC, biomechanical properties of the skin (pliability, viscoelasticity, and total recovery), and indicators related to dehydration in the serum and urine were measured before and 120 min after exercise. Higher values of the pliability and viscoelasticity, and lower value of the total recovery on the hand were demonstrated in the P-HYD trial compared to the DEH trial (all 0.05). Changes in the TDC were significantly correlated with changes in body mass, total body water, serum osmolarity, and hematocrit (all < 0.05). Changes in the biomechanical properties of the hand were significantly correlated with changes in body mass, hematocrit, and urine specific gravity (all 0.05). The present study showed that the changes in skin characteristics correlated with the body water and dehydration-associated indicators in the serum and urine, thus suggesting that skin characteristics may be useful in the assessment of dehydration.This study was the first to investigate the effect of dehydration and rehydration on the TDC and biomechanical properties of the skin upon instrumental measure, and not manual testing.This study confirmed the decline in aerobic capacity by dehydration and immediate recovery with sufficient rehydration.Changes in the TDC and the biomechanical properties of the skin correlated with the body water and dehydration-associated indicators in the serum and urine.Skin characteristics may be useful in the assessment of dehydration.
Topics: Male; Adult; Humans; Dehydration; Fluid Therapy; Drinking; Exercise; Osmolar Concentration; Water-Electrolyte Balance
PubMed: 35179449
DOI: 10.1080/17461391.2022.2044914 -
Journal of Veterinary Internal Medicine 2023Heart failure-associated hypochloremia can be depletional from diuretics or dilutional from water retention. Serum osmolality reflects water balance but has not been...
BACKGROUND
Heart failure-associated hypochloremia can be depletional from diuretics or dilutional from water retention. Serum osmolality reflects water balance but has not been evaluated in dogs with heart disease.
HYPOTHESIS
To determine if serum osmolality is related to heart disease stage and amount of mathematical correction of serum chloride (Cl ) concentrations in healthy dogs and dogs with myxomatous mitral valve degeneration (MMVD).
ANIMALS
Seventy-seven dogs (20 healthy, 25 Stage B MMVD, 32 Stage C/D MMVD).
METHODS
Serum Cl concentrations were mathematically corrected. Osmolality was calculated (calOsm) and directly measured by freezing point depression (dmOsm) and compared by Bland-Altman analysis. Biochemical variables and osmolality were compared among healthy, Stage B, and Stage C/D dogs. Correlations were explored between osmolality and biochemical variables. Median and range are presented. P < .05 was considered significant.
RESULTS
The calOsm was different among groups (P = .003), with Stage B (310 mOsm/kg; 306, 316) and C/D dogs (312 mOsm/kg; 308, 319) having higher calOsm than healthy dogs (305 mOsm/kg; 302, 308). Osmolality methods were moderately correlated (P < .0001, r = .46) but with proportional bias and poor agreement. The amount of Cl correction was negatively correlated with calOsm (P < .0001, r = -.78) and dmOsm (P = .004, r = -.33). Serum bicarbonate concentration was negatively correlated with Cl (P < .0001, r = -.67).
CONCLUSIONS AND CLINICAL IMPORTANCE
Dogs with Stage B and Stage C/D heart disease had higher calOsm than healthy dogs. Osmolality was inversely related to the amount of Cl correction, which supports its use in assessing relative body water content. Poor agreement between calOsm and dmOsm prevents methodological interchange.
Topics: Dogs; Animals; Chlorides; Heart Diseases; Mitral Valve Prolapse; Heart Failure; Osmolar Concentration; Water; Dog Diseases
PubMed: 37702389
DOI: 10.1111/jvim.16863 -
Public Health Nutrition Sep 2022Evaluating the association of water intake and hydration status with nephrolithiasis risk at the population level.
OBJECTIVE
Evaluating the association of water intake and hydration status with nephrolithiasis risk at the population level.
DESIGN
It is a cross-sectional study in which daily total plain water intake and total fluid intake were estimated together with blood osmolality, urine creatinine, urine osmolality, urine flow rate (UFR), free water clearance (FWC) and urine/blood osmolality ratio (U:B). The associations of fluid intake and hydration markers with nephrolithiasis were evaluated using multivariable logistic regression.
SETTING
General US population.
PARTICIPANTS
A total of 8195 adults aged 20 years or older from the National Health and Nutritional Examination Survey 2009-2012 cycles.
RESULTS
The population medians (interquartile ranges, IQR) for daily total plain water intake and total fluid intake were 807 (336-1481) and 2761 (2107-3577) ml/d, respectively. The adjusted OR (95 % CI) of nephrolithiasis for each IQR increase in total plain water intake and total fluid intake were 0·92 (95 % CI 0·79, 1·06) and 0·84 (95 % CI 0·72, 0·97), respectively. The corresponding OR of nephrolithiasis for UFR, blood osmolality, U:B and urine creatinine were 0·87 (95 % CI 0·76, 0·99), 1·18 (95 % CI 1·06, 1·32), 1·38 (95 % CI 1·17, 1·63) and 1·27 (95 % CI 1·11, 1·45), respectively. A linear protective relationship of fluid intake, UFR and FWC with nephrolithiasis risk was observed. Similarly, positive dose-response associations of nephrolithiasis risk with markers of insufficient hydration were identified. Encouraging a daily water intake of >2500 ml/d and maintaining a urine output of 2 l/d was associated with a lower prevalence of nephrolithiasis.
CONCLUSION
This study verified the beneficial role of general water intake recommendations in nephrolithiasis prevention in the general US population.
Topics: Adult; Biomarkers; Creatinine; Cross-Sectional Studies; Drinking; Humans; Kidney Calculi; Nutrition Surveys; Osmolar Concentration
PubMed: 35514256
DOI: 10.1017/S1368980022001033