Differences In Osmolarity Research Articles

The new preservative-free ophthalmic formulation of bilastine 0.6% preserves the ocular surface epithelial integrity in a comparative in vitro study

Allergic conjunctivitis (AC) is the most common form of allergic eye disease and an increasingly prevalent condition. Topical eye drop treatments are the usual approach for managing AC, although their impact on the ocular surface is not frequently investigated. The aim of this study was to perform a comparative physicochemical characterization, and in vitro biological evaluations in primary conjunctival and corneal epithelial cells of the new multidose preservative-free bilastine 0.6% and main commercially available eye drops. MTT assay was used to measure cell viability; oxidative stress was analyzed with a ROS-sensitive probe; and apoptosis was evaluated monitoring caspase 3/7 activation. Differences in pH value, osmolarity, viscosity and phosphate levels were identified. Among all formulations, bilastine exhibited pH, osmolarity and viscosity values closer to tear film (7.4, 300 mOsm/l and ~ 1.5–10 mPa·s, respectively), and was the only phosphates-free solution. Single-dose ketotifen did not induce ROS production, and single-dose azelastine and bilastine only induced a mild increase. Bilastine and single-dose ketotifen and azelastine showed high survival rates attributable to the absence of preservative in its formulation, not inducing caspase-3/7-mediated apoptosis after 24 h. Our findings support the use of the new bilastine 0.6% for treating patients with AC to preserve and maintain the integrity of the ocular surface.

Capability of the Inter-Eye Differences in Osmolarity, Break-Up Time and Corneal Staining on the Diagnostic of Dry Eye

ABSTRACT Purpose Inter-eye variability is a recognized characteristic of Dry Eye Disease (DED) and has been proposed as a diagnostic indicator in clinical practice. This study aimed to assess the diagnostic potential of the absolute difference between eyes in three key diagnostic tests recommended by the Tear Film and Ocular Surface Society Dry Eye Workshop II (TFOS DEWS II) Diagnostic Methodology report: tear film osmolarity, Fluorescein Break-Up Time (FBUT), and ocular surface staining. Methods A total of 180 participants were included in a cross-sectional study. Before a dry eye examination, participants completed an online self-administered OSDI questionnaire. The TFOS DEWS II diagnostic criteria for DED assessment were used: along with OSDI, osmolarity, FBUT and ocular surface staining were measured in all participants in both eyes following standardized methodology. Based on signs and symptoms, participants were diagnosed as having No DED or DED. After diagnosis, the parameters were computed as the right and left eyes’ absolute inter-eye difference (|OD-OS|). Results Receiver Operating Characteristics analyses for computed parameters were used based on the previous diagnosis. ROC analyses showed that Osmolarity|OD-OS| have a diagnostic capability to differentiate between No DED and DED participants with a cut-off value of 9.5 mOsm/L (AUC = 0.745 ± 0.052, p < 0.003), whereas FBUT|OD-OS| and Corneal Stainning|OD-OS| have not (AUC, both p ≥ 0.160). Conclusion The present study found that the Osmolarity|OD-OS| parameter could be used as a diagnostic indicator for DED assessment, while the FBUT|OD-OS| and the Corneal Staining|OD-OS| parameters do not have this capability.

Diagnostic Performance of the Tear Meniscus Osmolarity Measurement for Dry Eye Disease in Rheumatoid Arthritis Patients.

The aim of our study was to evaluate the diagnostic capacity of the tear meniscus osmolarity measurement for dry eye disease (DED) in patients with rheumatoid arthritis (RA), using a portable osmometer based on electrical impedance and an integrated circuit technology (TearLab® (Escondido, CA, USA)). We included 101 RA patients, 81 patients with DED and 20 without DED (controls). We measured tear osmolarity and assessed other clinical diagnostic tests as suggested by the TFOS DEWS II composite reference standard diagnostic criteria for DED using Ocular Surface Disease Index (OSDI), Five-item Dry Eye Questionnaire (DEQ-5), fluorescein tear break-up time (F-TUBT), ocular surface staining (SICCA score), and other clinical parameters to classify DED subtypes. We analyzed the agreement between osmolarity and the TFOS DEWS II composite reference standard for DED diagnosis. We conducted receiver operating characteristic (ROC) curve analyses using the DED variable and its subtypes as dependent variables and the continuous variable for osmolarity or the inter-eye difference in osmolarity as independent variable. Sensitivity, specificity, and area under the curve for all potential cut-off points were obtained and reported from ROC curves. We found that tear meniscus osmolarity had a low diagnostic capacity for DED (AUC = 0.57). Tear meniscus osmolarity measurement had a sensitivity of 35% and a specificity of 80% with a kappa level of agreement of 0.08 compared to the TFOS DEWS II composite reference standard. The low diagnostic capacity of the tear meniscus osmolarity was similar for aqueous-deficient DED and for evaporative DED, being only fair for severe DED with a 57% sensitivity and 80% specificity and a kappa level of agreement of 0.36. Our findings suggest that in patients with RA, tear meniscus osmolarity measured by the TearLab® showed low sensitivity, low specificity, and limited agreement with the TFOS DEWS II composite reference standard for DED diagnosis.

Prevalence of Dry Eye Disease Among Individuals Scheduled for Cataract Surgery in a Norwegian Cataract Clinic.

To determine the prevalence of dry eye disease (DED) in patients scheduled for cataract surgery in a Norwegian eye clinic. 218 patients scheduled for cataract surgery were examined for DED in one randomly selected eye and questioned regarding symptoms and risk factors. Patients were diagnosed with DED if they fulfilled the DEWS II criteria with symptom score >12/100 with Ocular Surface Disease Index (OSDI) questionnaire, and the presence of any of the three signs: tear osmolarity >307 mOsm/L in either eye or a difference in osmolarity between the two eyes of >8 mOsm/L, corneal fluorescein staining (CSF) ≥ grade 2 and non-invasive tear film breakup time (NIKBUT) of <10 seconds. Additional tests were the Standard Patient Evaluation of Eye Dryness (SPEED) questionnaire, tear meniscus height (TMH), Schirmer 1, tear film thickness (TFT), corneal sensitivity and meibography (meiboscore). Dry eye test outcomes were correlated with risk factors for DED. The prevalence of DED was 55.5% according to the DEWS II criteria. The abnormal osmolarity percentage was 66.5, while 29.8% had shortened NIKBUT and 19.7% exhibited CFS ≥2. 57% had Schirmer 1 ≤ 10 mm/5 min, and 81.1% had a meiboscore of ≥1. 71.2% of subjects scored positive for DED symptoms using the OSDI questionnaire and 69.3% using SPEED. Logistic regression analysis showed that higher age correlated with a lower OSDI symptom score, reduced corneal sensitivity and increased meibomian gland atrophy. Female sex was associated with higher odds of having DED, abnormal NIKBUT and abnormal CFS. Ocular tests for DED did not correlate with OSDI symptom scores when assessed with Spearman`s rank analysis. The prevalence of DED in an elderly Norwegian population scheduled for cataract surgery is high and associated with female sex. There was a lack of correlation between signs and symptoms of DED.

The epidemiology of dry eye disease in the UK: The Aston dry eye study

PurposeCross-sectional studies on dry eye disease (DED) have relied on different diagnoses hindering conclusions about the disease epidemiology. This study offers an insight into DED epidemiology in the UK using prior and recent diagnostic recommendations. MethodsStudy participants comprised 282 volunteers from Birmingham, UK (median 40 years, range 18–88 years, 56% females). DED was defined by the Tear Film Ocular Surface Dry Eye Workshop II (TFOS DEWS II) criteria, based on a positive symptom score with the Dry Eye Questionnaire (DEQ-5) and Ocular Surface Disease Index (OSDI), and one of the following homeostasis markers: non-invasive tear break-up time of < 10 s (Oculus Keratograph 5M); the highest osmolarity value of ≥ 308 mOsm/L among eyes or an interocular osmolarity difference of > 8 mOsm/L (TearLab Osmolarity System); or > 5 corneal spots, >9 conjunctival spots or lower/upper lid-wiper-epitheliopathy staining of ≥ 2 mm length and ≥ 25% width (Oculus Keratograph 5 M). In addition, the Women’s Health Study (WHS) criteria, based on symptoms or a prior dry eye diagnosis, was assessed. DED risk factors were gathered using a self-administered questionnaire. ResultsDED prevalence by the TFOS DEWS II criteria was 32.1% (95% confidence interval 25.5–37.7% and 29.5% (95% confidence interval 24.4–35.1% by the WHS criteria. Female sex, systemic and/or ocular health conditions, short sleep duration and prolonged outdoor leisure time spent were significant DED risk factors (p ≤ 0.05). ConclusionsApproximately one-third of the adult UK population have DED, aligning with the prevalence reported in multiple counties globally. Female sex, systemic/ocular health conditions, short sleep duration and prolonged outdoor leisure time are positive predictors of DED.

The Significance of Inter-Eye Osmolarity Difference in Dry Eye Diagnostics.

The purpose of this study was to evaluate the diagnostic value of inter-eye osmolarity differences in relation to dry eye symptoms and other non-osmolar signs of dry eye disease. One hundred ninety one participants who attended a larger interventional study of dry eye disease prior to and after cataract surgery were analyzed for dry eye disease (DED). Dry eye diagnostics were performed for all subjects according to the DEWS II criteria: tear osmolarity was collected from both eyes with the TearLab system, non-invasive Tear film break up time (NIKBUT) was obtained on the test eye with Keratograph and ocular surface staining (OSS) was evaluated using the Oxford schema. The Ocular Surface Disease Index (OSDI) questionnaire was used to assess symptoms. Inter-eye osmolarity greater than 8, which is considered as a sign of DED according to the TearLab user manual, was evaluated and compared with other non-osmolar signs of DED. The 191 subjects were divided into three groups according to osmolarity measurements. Sixty-five subjects had normal osmolarity (below 308 mOsmol/L in both eyes and less than 9 mOsmol/L difference between the eyes), 107 had high osmolarity (308 mOsmol/L or higher in one of the eyes) and 19 had an inter-eye difference >8 mOsmol/L or higher, with neither eye having osmolarity higher than 307 mOsmol/L. Signs and symptoms in this last group were not correlated with the high osmolarity group or the normal group, though they appeared more similar to the normal group. The diagnostic value of inter-eye osmolarity difference in predicting symptoms or other non-osmolar signs of dry eyes appears weak. Our study suggests that the criterion of an inter-eye difference of 8 mOsmol/L is not a useful cut-off for diagnosing dry eyes based on osmolarity.

The Effect of Prolactinoma on Tear Film Function.

To compare dry eye parameters in prolactinoma patients and healthy controls and evaluate their correlation with prolactin (PRL) levels and the duration of hyperprolactinemia. Consecutive patients with prolactinoma and healthy controls were included in the study. Schirmer, tear break-up time (TBUT), tear osmolarity values, and ocular surface disease index (OSDI) scores were evaluated for each patient. Follow-up time and total duration of hyperprolactinemia were recorded for prolactinoma patients. The study included 39 eyes of 39 patients with prolactinoma and 39 eyes of 39 age- and gender-matched healthy controls. Prolactinoma patients showed lower Schirmer (14.1±8.4 vs. 24.8±8.9 mm; p<0.001) and TBUT values (7.0±3.2 vs. 11.6±2.6 s; p<0.001) and higher OSDI scores (20.6±16.6 vs. 5.8±2.4; p<0.001) compared to the healthy controls. While the mean osmolarity of the prolactinoma patients was 301.6±8.3 mOsm/L, it was 297.7±12.5 mOsm/L for the healthy controls (p=0.07). The duration of hyperprolactinemia in prolactinoma patients showed a negative correlation with Schirmer (r=-0.395; p=0.013) and TBUT values (r=-0.377; p=0.018) and a positive correlation with OSDI scores (r=0.337; p=0.036). Prolactinoma patients had significantly lower Schirmer and TBUT levels and higher OSDI scores compared to the healthy controls, but no significant difference in tear osmolarity. The effect of high PRL levels on tear film function was duration-dependent.

A Metal Ion and Thermal-Responsive Bilayer Hydrogel Actuator Achieved by the Asymmetric Osmotic Flow of Water between Two Layers under Stimuli.

Shape-morphing hydrogels have drawn great attention due to their wide applications as soft actuators, while asymmetric responsive shape-morphing behavior upon encountering external stimuli is fundamental for the development of hydrogel actuators. Therefore, in this work, bilayer hydrogels were prepared and the shrinkage ratios (LA/LN) of the AAm/AAc layer to the NIPAM layer immersed in different metal ion solutions, leading to bending in different directions, were investigated. The difference in the shrinkage ratio was attributed to the synergistic effect of the osmolarity difference between the inside and outside of the hydrogels and the interaction difference between the ion and hydrogel polymer chains. Additionally, under thermal stimuli, the hydrogel actuator would bend toward the NIPAM layer due to the shrinkage of the hydrogel networks caused by the hydrophilic–hydrophobic phase transition of NIPAM blocks above the LCST. This indicates that metal ion and thermal-responsive shape-morphing hydrogel actuators with good mechanical properties could be used as metal ion or temperature-controllable switches or other smart devices.

Tear matrix metalloproteinase-9 levels may help to follow a ocular surface injury in lagophthalmic eyes.

The preocular tear film is critically important for maintaining healthy ocular surface. In lagophthalmos, increased evaporation and tear film instability can occur. The level of tear matrix metalloproteinase 9 (MMP-9) is considered as a possible marker of ocular surface damage and inflammation. The aim of this study was to evaluate the possible usefulness of measuring tear film levels of MMP-9 in patients with lagophthalmos. Sixteen adult patients with unilateral lagophthalmos due to cerebellopontine angle mass surgery were included. Basic clinical examination including tear film osmolarity, degree of lagophthalmos, ocular surface sensitivity testing, corneal fluorescein staining, and tear break-up time (TBUT) were performed. Furthermore, tear MMP-9 quantification was performed and the values from lagophthalmic and contralateral healthy eye were compared. Possible correlations between tear MMP-9 levels and other parameters were analyzed. The Oxford score was higher in lagophthalmic eyes in comparison to healthy eyes. TBUT and corneal sensitivity were lower in lagophthalmic eyes. There was no difference in osmolarity between the two groups. Tear MMP-9 values were higher in lagophthalmic eyes. A higher MMP-9 value was associated with an increase in ocular surface fluorescein staining and a decrease of TBUT in lagophthalmic eyes. Tear MMP-9 may be used for monitoring ocular surface damage, contribute to early detection of inflammation progression and facilitate treatment adjustments.

Evidence for a Prehypertensive Water Dysregulation Affecting the Development of Hypertension: Results of Very Early Treatment of Vasopressin V1 and V2 Antagonism in Spontaneously Hypertensive Rats.

In addition to long-term regulation of blood pressure (BP), in the kidney resides the initial trigger for hypertension development due to an altered capacity to excrete sodium and water. Betaine is one of the major organic osmolytes, and its betaine/gamma-aminobutyric acid transporter (BGT-1) expression in the renal medulla relates to interstitial tonicity and urinary osmolality and volume. This study investigated altered water and sodium balance as well as changes in antidiuretic hormone (ADH) activity in female spontaneously hypertensive (SHR) and normotensive Wistar Kyoto (WKY) rats from their 3–5 weeks of age (prehypertensive phase) to SHR’s 28–30 weeks of age (established hypertension-organ damage). Young prehypertensive SHRs showed a reduced daily urine output, an elevated urine osmolarity, and higher immunostaining of tubule BGT-1, alpha-1-Na-K ATPase in the outer medulla vs. age-matched WKY. ADH circulating levels were not different between young prehypertensive SHR and WKY, but the urine aquaporin2 (AQP2)/creatinine ratio and labeling of AQP2 in the collecting duct were increased. At 28–30 weeks, hypertensive SHR with moderate renal failure did not show any difference in urinary osmolarity, urine AQP2/creatinine ratio, tubule BGT-1, and alpha-1-Na-K ATPase as compared with WKY. These results suggest an increased sensitivity to ADH in prehypertensive female SHR. On this basis, a second series of experiments were set to study the role of ADH V1 and V2 receptors in the development of hypertension, and a group of female prehypertensive SHRs were treated from the 25th to 49th day of age with either V1 (OPC21268) or V2 (OPC 41061) receptor antagonists to evaluate the BP time course. OPC 41061-treated SHRs had a delayed development of hypertension for 5 weeks without effect in OPC 21268-treated SHRs. In prehypertensive female SHR, an increased renal ADH sensitivity is crucial for the development of hypertension by favoring a positive water balance. Early treatment with selective V2 antagonism delays future hypertension development in young SHRs.

Effect of Vitamin C and Protein Supplementation on Plasma Nitrate and Nitrite Response following Consumption of Beetroot Juice.

Beetroot juice is a food high in nitrate and is associated with cardiometabolic health benefits and enhanced exercise performance through the production of nitric oxide in the nitrate–nitrite–nitric oxide pathway. Since various food components influence this pathway, the aim of this trial was to study the effect of beetroot juice alone and in conjunction with vitamin C or protein on the acute response to plasma nitrate and nitrite levels in healthy middle- to older-aged adults. In this cross-over trial, each participant received, in a randomized order, a single dose of Beet It Sport® alone; Beet It Sport®, plus a 200 mg vitamin C supplement; and Beet It Sport® plus 15 g of whey protein. Plasma levels of nitrate and nitrite were determined prior to and at 1 and 3 h after intervention. Log plasma nitrate and nitrite was calculated to obtain data that were normally distributed, and these data were analyzed using two-way within-factors ANOVA, with time and treatment as the independent factors. There were no statistically significant differences for log plasma nitrate (p = 0.308) or log plasma nitrite (p = 0.391) values across treatments. Log plasma nitrate increased significantly from pre-consumption levels after 1 h (p < 0.001) and 3 h (p < 0.001), but plasma nitrate was lower at 3 h than 1 h (p < 0.001). Log plasma nitrite increased from pre to 1 h (p < 0.001) and 3 h (p < 0.001) with log values at 3 h higher than at 1 h (p = 0.003). In this cohort, we observed no differences in log plasma nitrate and nitrite at 1 h and 3 h after co-ingesting beetroot juice with vitamin C or a whey protein supplement compared to beetroot juice alone. Further research needs to be undertaken to expand the blood-sampling time-frame and to examine factors that may influence the kinetics of the plasma nitrate to nitrite efficacy, such as differences in fluid volume and osmolarity between treatments employed.

High-fidelity biosensing of dNTPs and nucleic acids by controllable subnanometer channel PaMscS

Current tools for dNTP analysis mainly rely on expensive fluorescent labeling, mass spectrometry or electrochemistry. Single-molecule assay by protein nanopores with an internal diameter of ca. 1–3.6 nm provides a useful tool for dNTP sensing. However, the most commonly used protein nanopores require additional modifications to enable dNTP detection. In this study, the PaMscS channel (mechanosensitive channel of small conductance from Pseudomonas aeruginosa) embedded in the bilayer lipid membrane (BLM) of E. coli polar lipid extract was applied as a nanopore for single molecular sensing. Two mutants of PaMscS nanopores on the side portal region (PaMscS W130A and PaMscS K180R) were selected for direct dNTP or pyrophosphoric acid (PPi) detection without aptamer or protein modification. Notably, the PaMscS mutant pore can be adjusted by regulation of osmolarity differences, which is crucial for the optimal detection of specific molecules. In addition, we established a PaMscS-based diagnosis method for the rapid sensing of disease-associated nucleic acids by monitoring the consumption of dNTPs, with 86% specificity and 100% sensitivity among 22 clinical samples. This protein nanopore, without aptamer or modification, paves a new way for dNTPs, PPi direct sensing and nucleic acid detection with low cost but high versatility.

Intraocular Scattering, Blinking Rate, and Tear Film Osmolarity After Exposure to Environmental Stress

PurposeDry environments, such as those in offices or aircraft cabins, can potentially generate ocular discomfort and alter the tear film. We compare light scatter, blinking rate, and tear osmolarity in young and older subjects after exposure to low humidity using a controlled environmental chamber.MethodsTwo groups of healthy subjects were recruited; younger (N = 13, 27 ± 6 years) and older (N = 23, 71 ± 7 years). Measurements were carried out before and after 90-minute exposure to low relative humidity (5%) and constant temperature (23 degrees). Ocular light scatter was measured using a double-pass instrument (OQAS, Visiometrics, Spain). Blinking rate was monitored using an infrared video camera. Tear osmolarity was measured using the TearLab system (Escondido, CA, USA).ResultsOcular light scatter increased by a factor of 10% after exposure to low humidity in the older group (P = 0.03) but did not change significantly in the younger group. Blinking rate increased significantly (40% more blinks) in both groups but there was no difference between the groups. No significant differences in osmolarity were shown between two age groups or as result of environmental stress.ConclusionsExposure to dry environment increased light scatter in older subjects. Although more blinks were triggered in both younger and older groups to prevent corneal dehydration, there was no difference between the groups. Blink rate and osmolarity are not associated with the difference in light scatter.Translational RelevanceOur work approaches a clinical care problem using basic research methods (measuring ocular scatter and blink ratio).

The relationship between different dosages of mannitol 20% and osmolarity, blood sugar serum, and coagulation factors in moderate brain injury patients with increased intracranial pressure

ObjectiveTraumatic brain injuries have high mortality rates in many countries. Chemical parameters such as blood osmolarity, serum blood sugar, and coagulation factors can be used to assess the prognosis of a brain injury. Increased intracranial pressure and swelling of the brain are clinical manifestations of brain injury. One option for non-operative treatment is the use of mannitol (MT). This research aims to determine the dosage of MT 20% that demonstrates better levels of safety and effectiveness, based on the evaluation of 3 laboratory-test parameters. MethodThis research is a prospective cohort with a total sample of 30 patients with moderate brain injuries, who are divided randomly into two groups of different dosages of MT. ResultsThe results are analyzed using repeated measures ANOVA tests and are significant if p<0.05. We found differences in blood osmolarity, serum blood sugar, and coagulation factors between the two groups. A dosage of MT 20% 1g/kgBW has a higher value than a dosage of 0.5g/kgBW, but all were nonsignificant (p>0.05). ConclusionMT 20% does not affect blood osmolarity, serum blood sugar, and coagulation factors.

Ocular Surface Impairment After Coronavirus Disease 2019: A Cohort Study.

This is a cohort study to evaluate the presence of objective signs and subjective symptoms of dry eye disease in postcoronavirus disease 2019 (COVID-19) patients compared with the control. Prospective, observational, single-ctenter, cohort study. Sixty-four post-COVID-19 patients and 50 control were recruited. All participants underwent a complete ophthalmological examination including Ocular Surface Disease Index Questionnaire (OSDI), best-corrected visual acuity, slit-lamp biomicroscopy, fundus examination, Schirmer test type 1, tear break-up time test (tBUT), evaluation of conjunctival hyperemia, corneal staining, and tear film osmolarity test. The OSDI score was higher in the post-COVID-19 group in the quantitative and qualitative analysis (P < 0.001 and P =0.012, respectively). The mean tBUT in post-COVID-19 patients was 6.95 ± 4.07 seconds compared with a mean tBUT of 10.12 ± 3.90 seconds in the control group. The post-COVID-19 group showed a higher number of patients with a simultaneous impairment of the OSDI score and tBUT (P = 0.019). The Schirmer test results were strikingly significant both in the quantitative analysis and qualitative analysis (P <0.001 and P = 0.0014, respectively). Both quantitative analysis and qualitative analysis revealed a significant difference in tear osmolarity in the 2 groups. Comparing the ocular surface assessment of post-COVID-19 patients with heathy control, a statistically significant increase of dry eye disease has emerged both in subjective and objective evaluations. Our clinical results support the findings that suggested a susceptibility of the ocular surface to the virus, and it underlines the importance of the ocular surface assessment in post-COVID-19 patients for a correct diagnosis and therapy.

Niche partitioning between river shark species is driven by seasonal fluctuations in environmental salinity

Abstract Tropical rivers and estuaries are highly dynamic environments, where environmental conditions change dramatically over spatial and temporal scales. This creates both physiological and ecological challenges for euryhaline elasmobranchs, where fluctuations in salinity can impact not only osmoregulatory function but also the ability to find and acquire prey. We investigated how spatial and temporal variation in environmental salinity influences physiological homoeostasis, habitat utilization and migration timing in two euryhaline carcharhinid sharks within a tropical river in northern Australia. Neonate and juvenile bull sharks Carcharhinus leucas and speartooth sharks Glyphis glyphis were tracked over a 4‐year period using implanted acoustic tags and an array of hydrophone receivers. Tissue samples were also collected from captured sharks and analysed for interspecific differences in plasma osmolarity, urea and electrolyte (Na+ and K+) concentrations and the stable isotopes δ13C and δ15N. We discovered that immature C. leucas and G. glyphis segregate spatially along a salinity gradient between September and December, where the mean volume of intersection between species dropped as low as 0.01. While G. glyphis used higher salinity environments (mean salinity = 19.22) located between 30 and 70 km from the mouth of the estuary, C. leucas occupied freshwater reaches (mean salinity = 1.98) between 60 and 110 km upstream. Plasma osmolarities of both species were always hyperosmotic to the environment, with electrolyte concentrations maintained within a narrow range independent of environmental osmolarities. At the onset of the wet season, both C. leucas and G. glyphis undertook a coordinated downstream migration towards the lower estuary before returning upstream. Carcharhinus leucas blood tissues were more enriched in δ15N and δ13C than samples collected from similar size G. glyphis, suggesting that these species not only spatially segregate within low salinity habitats but also prey on different dietary resources. Furthermore, a loss of enriched isotopic values in fin tissue with increasing body length provides further support for marine use by adult sharks in conjunction with dependence on rivers as important nursery habitat. Our results illustrate the importance of long‐term integrative studies into resource competition and the significance of discrete brackish habitats for threatened euryhaline elasmobranchs. A free Plain Language Summary can be found within the Supporting Information of this article.

Effect of High Glucose on Hypoxia/Reoxygenation Injury in Mouse Diabetic Coronary Artery Endothelial Cells

BackgroundType 2 diabetes mellitus (DM2) remains an increasing cause of morbidity and mortality in the Western world, including coronary artery disease and myocardial infarction. In order to eventually test mechanisms of cardioprotection by different agents, we sought to develop an in‐vitro model of mouse DM2 coronary artery endothelial cells (ECs) undergoing hypoxia/reoxygenation (HR) injury under normal and high glucose concentrations. We hypothesized that high glucose exacerbates HR injury.MethodsDM2‐ECs, grown to confluency in complete media (5% fetal bovine serum and 5.5 mM glucose), were exposed to normal (5.5 mM) or high (20.5 mM) glucose concentrations for 72 hrs. They were then were subjected to normoxic (21% O2, complete media) or hypoxic (0.0125% O2, FBS‐ and glucose‐free media) conditions for 8 hrs, followed by reoxygenation in complete media for 16 hrs. To assess the extent of injury, cell (CyQUANT GR dye) and mitochondrial viability (3‐(4,5‐dimethylthiazol‐2‐yl)‐5‐(3‐carboxymethoxyphenyl)‐2‐(4‐sulfophenyl)‐2H‐tetrazolium; MTS) as well as cellular injury (lactate dehydrogenase release; LDH) were measured. Statistics: Two‐Way ANOVA followed by Tukey post‐hoc testing; alpha = 0.05 (two‐tailed).ResultsUnder both normal and high glucose conditions, HR caused a significant decrease in cell number and increase in LDH release, while MTS remained unchanged. The injury by HR under high compared to under normal glucose conditions, was not different at either outcome parameter.ConclusionsIn contrast to our hypothesis, 20.5 mM glucose did not significantly exacerbate HR‐induced cellular or mitochondrial injury and also did not lead to significantly increased injury under normoxic conditions. It is conceivable that the DM2‐ECs in our in‐vitro model perceive a concentration of 20.5 mM as closer to normal and a concentration of 5.5 mM lower than normal than would be anticipated in‐vivo. Another explanation could be that the hypoxia we chose (0.0125% O2 for 8 hrs) was not strong and/or long enough to cause a significant enough damage to be exacerbated by an additional stressor. We also did not control for differences in osmolarity between normal and high glucose experiments that might have skewed our results. More research under different conditions will be necessary to elucidate the interplay of high glucose and HR injury in DM2.Support or Funding InformationThis work was supported, in part, by institutional funds; by a Merit Review Award (I01 BX003482) from the U.S. Department of Veterans Affairs Biomedical Laboratory R&amp;D Service; by the American Heart Association’s PAECER Program (1R25HL145330); and by the National Institute of General Medical Sciences of the National Institutes of Health (R25GM113740).

Inter-eye osmolarity differences in patients with symptomatic and non-symptomatic dry eyes.

To analyze whether inter-eye osmo larity differences were related to dry eye symptomatology. A total of 135 participants were randomly recruited from those who visited in the Optometry Clinic of the Optometry Faculty (Universidade de Santiago de Compostela). In a single scheduled session after the recruitment, Ocular Surface Disease Index was filled out following the standard instructions and TearLab measurements were made in both the participants' eyes (10-15 min lapse). Osmolarity values were compared between the right and left eyes and the absolute inter-ocular difference (|OD-OS|) correlated with the Ocular Surface Disease Index score for the whole sample. Based on the Ocular Surface Disease Index score, the sample was divided into four symptomatic subgroups, and differences in the |OD-OS| values were calculated. The whole sample showed a statistically significant inter-eye osmolarity difference (p=0.025; |OD-OS| = 9.2 ± 9.3 mOsm/l) and the correlation between Ocular Surface Disease Index and |OD-OS| (r=0.369; p<0.001). A statistically significant difference was found in the |OD-OS| value between symptomatic subgroups (Kruskal-Wallis, p=0.003). Mann-Whitney U test showed a significant difference between asymptomatic vs. moderate (p=0.006) vs. severe symp tomatic patients (p=0.001) and between mild vs. severe symptomatic patients (p=0.045), whereas no difference on |OD-OS| was found between participants with contiguous symptomatic subgroups (all p³0.174). Tear film inter-eye osmolarity differences are significantly higher in severe dry eye disease symptoms.

Evaluation of Fluid Therapy by Point-of-Care Ultrasound in Hyperglycemic Emergencies

Aim: Diabetic ketoacidosis (DKA) and Hyperosmolar hyperglycemic state (HHS) are among the cases where total body fluid deficit is high. Although it is known that dehydration is one of the main determinants of mortality and morbidity, it is difficult to determine and follow up fluid treatment in patients with multiple comorbidities. Measurement of the respiratory variability of the vena cava inferior diameter and vena cava inferior / aortic diameter measurement can be performed easily and quickly at the bedside and have a high objectivity compared to physical examination. In this study, we evaluated the follow-up of fluid therapy by POCUS with vena cava inferior diameter and vena cava inferior diameter / abdominal aortic diameter ratio in patients presenting with hyperglycemic emergencies (DKA, HHS, severe hyperglycemia).&#x0D; Methodology: 56 patients diagnosed with severe hyperglycemia, DKA and HHS according to the American Diabetes Association (ADA) diagnostic criteria were included in the study. Vital signs, laboratory tests(venous blood gas analysis, complete urinalysis, osmolarity, fingertip blood glucose level), fluid volume and bedside ultrasonographic measurements [vena cava inferior inspiration and expiration (iVCI and eVCI) diameter,vena cava inferior colapsiability index (VCI index), abdominal aorta diameter and ratio of vena cava inferior to abdominal aorta diameter (VCI/Ao)] were recorded.&#x0D; Results: Of the 56 patients, 21.4% were diagnosed with DKA 8.9%, HHS and 69.6% with severe hyperglycemia. There was a significant difference in osmolarity and although pH values ​​were not statistically significant, it tended to improve with the amount of fluid given. There was a significant difference in iVCI, VCI index and VCI/Ao.&#x0D; Conclusion: We believe that planning and monitoring fluid treatment with bedside ultrasonographic VCI diameter and VCI/Ao ratio measurements will reduce the undesirable complications, the intensity of emergency services, long waiting time and follow-up periods and will contribute to patient benefit and emergency departments.

The effect of lid hygiene on the tear film and ocular surface, and the prevalence of Demodex blepharitis in university students

AimTo evaluate the effect blepharitis lid cleansers have on the tear film and ocular surface, and to examine the prevalence of Demodex folliculorum in a young population. MethodsForty-eight university students completed a randomised, controlled, investigator-masked, eight-week clinical trial. Three eyelid hygiene products were investigated: blepharitis eyelid cleanser (OCuSOFT® Lid Scrub® PLUS foam), diluted baby shampoo (10% Johnson’s® No More Tears ®) and a tea-tree based face wash (dr.organic®). Cooled boiled water was used as a control. Subjects attended for four visits: baseline, two weeks, four weeks and eight weeks. At each visit, subjective symptoms, non-invasive tear break up time, ocular surface staining and Demodex folliculorum investigation were assessed to evaluate any positive or negative effect on the tear film and ocular surface. Osmolarity was also measured at baseline and week eight only. ResultsThe overall prevalence of Demodex folliculorum found at baseline was 15%. Subjective symptoms improved in all groups, including control. There was no significant difference in mean osmolarity between the groups or within each group after eight weeks. There was a significant increase in osmolarity inter-eye variability in the baby shampoo group (5.5 ± 5.4 vs 15.2 ± 9.5; p = 0.03). There was no significant change in non-invasive tear break up time or ocular surface staining demonstrated after eight weeks of eyelid hygiene. ConclusionA low prevalence of Demodex folliculorum can be found in a young population. All blepharitis lid cleansers used demonstrated subjective improvement in symptoms, with no negative effects on tear break-up time or ocular surface staining. The blepharitis eyelid cleanser and tea-tree based face wash revealed no adverse effect on mean osmolarity or inter-eye variability. Similarly, baby shampoo did not cause a significant increase in mean osmolarity, however, a significant increase in inter-eye variability was found; suggesting a possible increase in ocular surface inflammation.