Osmolality Of Solution Research Articles

Arrhythmogenic Potential of Myocardial Edema: The Interstitial Osmolality Induces Spiral Waves and Multiple Excitation Wavelets.

Myocardial edema is a common symptom of pathological processes in the heart, causing aggravation of cardiovascular diseases and leading to irreversible myocardial remodeling. Patient-based studies show that myocardial edema is associated with arrhythmias. Currently, there are no studies that have examined how edema may influence changes in calcium dynamics in the functional syncytium. We performed optical mapping of calcium dynamics on a monolayer of neonatal rat cardiomyocytes with Fluo-4. The osmolality of the solutions was adjusted using the NaCl content. The initial Tyrode solution contained 140 mM NaCl (1T) and the hypoosmotic solutions contained 105 (0.75T) and 70 mM NaCl (0.5T). This study demonstrated a sharp decrease in the calcium wave propagation speed with a decrease in the solution osmolality. The successive decrease in osmolality also showed a transition from a normal wavefront to spiral wave and multiple wavelets of excitation with wave break. Our study demonstrated that, in a cellular model, hypoosmolality and, as a consequence, myocardial edema, could potentially lead to fatal ventricular arrhythmias, which to our knowledge has not been studied before. At 0.75T spiral waves appeared, whereas multiple wavelets of excitation occurred in 0.5T, which had not been recorded previously in a two-dimensional monolayer under conditions of cell edema without changes in the pacing protocol.

Physical properties of soft contact lens multipurpose solutions commercially available in Ghana

PurposeTo investigate the physical properties of commercially available multipurpose soft contact lens solutions in Ghana. MethodspH (Kelilong ICL-099 pH meter, China), osmolality (OSMOMAT 3000, GONOTEC, Germany), surface tension (Sigma 700 Tensiometer, Sweden), and viscosity (CFOC-200 Viscometer, Cannon Company, USA) of various soft contact lens multipurpose solutions (MPS) were measured in triplicates at room temperature. Viscosity measurements were also taken at 34 °C ocular surface temperature. The solutions examined were Opti-Free Replenish (OFR), Trufresh (TF), Avizor (AV), Freshlook (FL), and Refresh (RF). ResultsSeveral solutions were largely hypo-osmotic in the range of 108–231 mOsm/kg, the exception being Avizor, which had osmolality values that were closer to human tears (301 ± 0.58 mOsm/kg). The range of pH values of the solutions (6.33–8.24, mean (SD) = 7.53 ± 0.18) fell within the reported tolerable range for the ocular surface (6.20–9.00). Surface tension values ranged from 35.86 to 42.27 mNm with a mean of 38.49 ± 2.32 mNm. The average viscosity of most solutions at room temperature (25 °C) was 1.44 ± 0.49 cP with a range of 1.04–2.15 cP. Significantly lower values ranging from 0.79 to 1.58 cP were obtained at ocular surface temperature (34 °C), p = 0.0001). ConclusionsThe physical properties of many of the solutions used as MPS in Ghana are markedly variable. Nevertheless, pH, surface tension, and viscosity fall within the acceptable limits of ocular physiological tolerance; except for osmolality, which majority were outside the reported tolerable range for the ocular surface. This information may partly explain the reason some patients exhibit strong preferences for certain care systems and should aid clinical decision-making when prescribing eye care systems to patients.

N-Methyl-D-aspartic acid (NMDA) mediated vasodilation in aorta

Although N-Methyl-D-aspartic acid (NMDA) mediated vasodilation has been extensively studied in cerebral circulation, there are limited studies that address the NMDA-mediated vascular responses at the peripheral vascular system. In this study our objective is to address the peripheral vascular responses mediated by NMDA. Vascular responses were obtained via in vitro myography on thoracic aorta segments isolated from C57BL/6 wild type male mice. NMDA at the concentration range of 100 micromolar to 1 millimolar in aortic segments precontracted by 1 micromolar phenylephrine. Maximal vasodilation of 75% in reference to baseline prior to drug application was observed at 3mM NMDA. NMDA receptor blockade by MK-801 did not change NMDA-induced vasodilation (55% vs 58%). Neither vehicle of NMDA, nor corresponding osmolar solutions of mannitol to NMDA concentrations induced vasodilation. Nitric oxide synthase (NOS) inhibition by 100 micromolar m Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME) reduced 3mM NMDA induced vasodilation from 75% to 16%. Removal of endothelial cell layer did not change the vasodilation mediated by NMDA. NMDA at millimolar concentrations relaxes vascular smooth muscle via non-endothelium dependent and NMDA-receptor independent mechanisms. Vasodilatory response to NMDA appears partially mediated by NOS. It is possible that NMDA is exerting its vasodilatory effects via non-NMDA receptors on the vascular smooth muscle. Whether NMDA-induced vasorelaxation is observed in resistance arteries remains warranted. PSC CUNY 66608-00 54. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Response of Articular Cartilage to Hyperosmolar Stress: Report of an Ex Vivo Injury Model

Background: Physiological 0.9% saline is commonly used as an irrigation fluid in modern arthroscopy. There is a growing body of evidence that a hyperosmolar saline solution has chondroprotective effects, especially if iatrogenic injury occurs. Purpose: To (1) corroborate the superiority of a hyperosmolar saline solution regarding chondrocyte survival after mechanical injury and (2) observe the modulatory response of articular cartilage to osmotic stress and injury. Study Design: Controlled laboratory study. Methods: Osteochondral explants were isolated from bovine stifle joints and exposed to either 0.9% saline (308 mOsm) or hyperosmolar saline (600 mOsm) and then damaged with a sharp dermatome blade to attain a confined full-thickness cartilage injury site, incubated in the same fluids for another 3 hours, and transferred to chondropermissive medium for further culture for 1 week. Chondrocyte survival was assessed by confocal imaging, while the cellular response was evaluated over 1 week by relative gene expression for apoptotic and inflammatory markers and mediator release into the medium. Results: The full-thickness cartilage cut resulted in a confined zone of cell death that mainly affected superficial zone chondrocytes. Injured samples that were exposed to hyperosmolar saline showed less expansion of cell death in both the axial (P < .007) and the coronal (P < .004) plane. There was no progression of cell death during the following week of culture. Histological assessment revealed an intact cartilage matrix and normal chondrocyte morphology. Inflammatory and proapoptotic genes were upregulated on the first days postexposure with a notable downregulation toward day 7. Mediator release into the medium was concentrated on day 3. Conclusion: This in vitro cartilage injury model provides further evidence for the chondroprotective effect of a hyperosmolar saline irrigation fluid, as well as novel data on the capability of articular cartilage to quickly regain joint homeostasis after osmotic stress and injury. Clinical Relevance: Raising the osmolarity of an irrigating solution may be a simple and safe strategy to protect articular cartilage during arthroscopic surgery.

495 Optimizing Drug Delivery to the Brain for Breast Metastasis: A Novel Method for Tumor Targeting

INTRODUCTION: Brain metastases are difficult to treat due to the blood-brain barrier limiting delivery of therapeutic agents to the brain effectively. Intraventricular drug delivery has not been well studied for intra-axial pathologies. However, our prior work demonstrated that intraventricular drug delivery in a hyperosmolar vehicle showed preferential accumulation of drug within breast cancer tissue compared to surrounding brain parenchyma. METHODS: We used an intracerebral breast cancer tumor model in adult female nude rats divided into six experimental groups. We examined three iron labeled dextran molecules (3 KD, 5KD, and 10 KD) in 337 mOsm/L solution and three different osmolarities of delivery solution (307, 353, 368 mOsm/L) with 10 KD dextran. 7T MR imaging was used to analyze dextran distribution at different time points. All animals were sacrificed after 2 hours and quantity of dextran particles was determined by histopathology. RESULTS: Breast cancer tumor cells were successfully implanted in all rats. MRI quantification of dextran concentration was well corroborated by histopathology. Varying the molecular size of dextran resulted in the smallest molecule reaching peak levels in tumor tissue earlier than the larger molecules but the larger molecules remained concentrated in tumor tissue for a longer time. Varying the osmolarity of the delivery solution resulted in preferential accumulation of 10 KD dextran in tumor tissue except for when dextran was delivered in 368 mOsm/L solution where no preferential distribution was seen. CONCLUSIONS: Hyperosmolar intraventricular delivery of chemotherapeutic drugs could be effective in preferentially delivering drugs to abnormal tumor tissues.

Microfluidic Single-Cell Study on Arabidopsis thaliana Protoplast Fusion-New Insights on Timescales and Reversibilities.

Plant cells are omnipotent and breeding of new varieties can be achieved by protoplast fusion. Such fusions can be achieved by treatment with poly(ethylene glycol) or by applying an electric field. Microfluidic devices allow for controlled conditions and targeted manipulation of small batches of cells down to single-cell analysis. To provide controlled conditions for protoplast fusions and achieve high reproducibility, we developed and characterized a microfluidic device to reliably trap some Arabidopsis thaliana protoplasts and induced cell fusion by controlled addition of poly(ethylene glycol) (PEG, with a molecular weight of 6000). Experiments were conducted to determine the survival rate of isolated protoplasts in our microfluidic system. Afterward, PEG-induced fusion was studied. Our results indicate that the following fusion parameters had a significant impact on the fusion efficiency and duration: PEG concentration, osmolality of solution and flow velocity. A PEG concentration below 10% led to only partial fusion. The osmolality of the PEG fusion solution was found to strongly impact the fusion process; complete fusion of two source cells sufficiently took part in slightly hyper-osmotic solutions, whereas iso-osmotic solutions led to only partial fusion at a 20% PEG concentration. We observed accelerated fusion for higher fluid velocities. Until this study, it was common sense that fusion is one-directional, i.e., once two cells are fused into one cell, they stay fused. Here, we present for the first time the reversible fusion of protoplasts. Our microfluidic device paves the way to a deeper understanding of the kinetics and processes of cell fusion.

Protein Preferential Solvation in (Sucralose + Water) Mixtures.

Addition of sugars such as sucrose to aqueous protein solutions generally stabilizes proteins against thermal denaturation by preferential exclusion of sugars from proteins (preferential hydration of proteins). In this study, we investigated the effect of sucralose, a chlorinated sucrose derivative, on protein stability and preferential solvation. Circular dichroism and small-angle X-ray scattering measurements showed that sucrose increased the denaturation temperature of myoglobin and was preferentially excluded from the protein, whereas sucralose decreased the denaturation temperature of myoglobin and was preferentially adsorbed to the protein. No clear evidence was obtained for the indirect effects of sucralose on protein destabilization via the structure and properties of solvent water from the physicochemical properties (mass density, sound velocity, viscosity, and osmolality) of aqueous sucralose solutions; therefore, we concluded that a direct protein-sucralose interaction induced protein destabilization.

Oral electrolyte supplementation and prevention of dehydration in horses

Dehydration is common in equine disciplines and can be avoided by effective oral rehydration strategies. Thermoregulatory loss of heat in horses requires sweating which, in turn, can result in considerable loss of water and electrolytes. Maintenance of hydration and prevention of dehydration requires the continuous replacement of lost electrolytes and water. The stomach and small intestine can function as reservoirs to facilitate the uptake of water and electrolytes consumed 1–2 hours prior to competitions, training and transport. Ions and water are rapidly absorbed in the small intestine and taken up by muscles and the skin, where they serve to replace losses resulting from muscle contraction and sweating. An effective electrolyte supplement replaces electrolytes in the proportion that they are lost through sweating; failure to do this results in an electrolyte imbalance. Electrolyte solution osmolality must be maintained at less than that of bodily fluids to promote gastric emptying and intestinal absorption. Palatability of the electrolyte supplement should be high, and horses should be trained to drink the solution voluntarily before any dehydrating event to try to prevent dehydration from occurring.

Magnitude of Fruit Juice-Drug Interactions Due to Osmolality-Dependent Fluid Secretion: Differences among Apple, Orange, and Grapefruit Juices.

We recently reported that the gastrointestinal (GI) fluid volume is influenced by the solution osmolality, and proposed that this effect may play a role in beverage-drug interactions. Here, we investigated whether osmolality-dependent fluid secretion can explain the difference in the magnitudes of fruit juice-drug interactions depending on the type of fruit juice (grapefruit juice (GFJ), orange juice (OJ), and apple juice (AJ)). The osmolality of GFJ, OJ, and AJ used in this study was found to be 552, 686, and 749 mOsm/kg, respectively. Measurements of intestinal fluid movement following beverage administration by the in situ closed-loop technique revealed the following rank order for fluid volume in rat ileum: AJ > OJ > GFJ > purified water, suggesting that water movement is dependent on the osmolality of these beverages. Such changes in GI fluid volume are expected to alter the luminal drug concentration, potentially contributing to the magnitude of beverage-drug interactions. Indeed, in vivo pharmacokinetic study in rats revealed that the plasma concentration of atenolol, a low-permeability drug, was the highest after oral administration in purified water, followed by GFJ and OJ, and was the lowest after administration in AJ. In contrast, antipyrine, a high-permeability drug, showed no significant difference in plasma concentration after administration in purified water and fruit juices, suggesting that the absorption of high-permeability drugs is less affected by solution osmolality. Our findings indicate that differences in the magnitude of beverage-drug interactions can be at least partly explained by differences in the osmolality of the beverages ingested.

Effect of pH, osmolality, Na+ and K+ on spermatozoa motility of the orange-spotted grouper, Epinephelus coioides

ABSTRACT The present study investigated the biosensitivity of Epinephelus coioides spermatozoa under various ionic and osmolality conditions. Activation and sensitivity of sperm started at different pH (7, 7.5, 8, 8.5, and 9) level. The highest motility duration was obtained in pH 8.5 with a significant difference to other groups (P < .001). The E. coioides spermatozoa exposed to 600 mM NaCl solution, 300 mM KCl (in the medium containing 200 mM sucrose), and sucrose solutions with 1100 mosmol/kg osmolality had significantly higher duration of motility than those exposed to solutions with the lower amount of NaCl, KCl and osmolality. Any amount greater than 600 mM NaCl, 300 mM KCl and 1100 mosmol/kg osmolality showed a remarkable reduction in the motility of spermatozoa. Results also showed that the amount of 100 and 450 mM K+, and osmolality lower than 400 mosmol/kg had a significant inhibitory effect and prevented the activity of spermatozoa. The findings of this study showed that changes in K+, Na+ and osmolality of the external solutions affects the spermatozoa and its motility. The potential use of these ions could be applicable for the improvement of the spermatozoa quality of E. coioides during artificial reproduction.

Artículo traducido] Caracterización y resultados del uso de voriconazol nebulizado en un entorno real: un estudio observacional unicéntrico

ObjectivePulmonary administration of voriconazole involves advantages, including optimization of lung penetration and reduction of adverse effects and interactions. However, there is scarce evidence about its use and there are no commercial presentations for nebulization. We aim to characterize a compounded voriconazole solution for nebulization and describe its use in our center. MethodThis is a retrospective observational study including patients who received nebulized voriconazole to treat fungal lung diseases (infection or colonization). Voriconazole solution was prepared from commercial vials for intravenous administration. ResultsThe pH and osmolarity of voriconazole solutions were adequate for nebulization. Ten patients were included, nine adults and a child. The dosage was 40 mg in adults and 10 mg in the pediatric patient, diluted to a final concentration of 10 mg/ml, administered every 12-24 hours. The median duration of treatment was 139 (range: 26-911) days. There were no reported adverse effects and the drug was not detected in plasma when nebulized only. ConclusionVoriconazole nebulization is well tolerated and it is not absorbed into the systemic circulation; further research is needed to assess its efficacy.

Linking surface tension to water polarization with a new hypothesis: The Ling-Damodaran Isotherm.

Studying aqueous solutions of complex (bio)polymers is essential from both theoretical and practical perspectives. To understand the principles that govern the properties of these solutions is pivotal for the study of biological processes, considering that the most distinguished components of the cells are polymers (proteins, nucleic acids). These macromolecular aqueous systems, known as colloids, has raise the interest of scientists in recent years. It is known that several physicochemical properties deviate from ideal behaviour in this kind of solutions and that the physical state of water is different compared to its pure state. Particularly, the surface tension of such mixtures often shows a peculiar profile at semi-dilute and concentrated conditions. Here, we joined the colloidal concept of water polarization (proposed in the Association-Induction Hypothesis) with Damodaran's formalism for surface tension to theoretically derive a compelling mathematical model that explains the behaviour of polymer solutions. We measured the surface tension and osmolarity of different polyethylene oxide solutions and we used the ACDAN fluorescence probe to assess the water dipolar relaxation (polarization) in these mixtures. As a proof of concept, we also studied the influence of these polymer solutions on lipid interfaces. Our isotherm model explains the experimental observations with a unifying view that correlates with other measured properties, such as osmolarity and water dipolar relaxation. This provides a link between interfacial and bulk physicochemical properties of polymer solutions, also giving a new framework for studying the interaction of colloidal systems with lipid membranes interfaces.

Characterization and real-live results of nebulized voriconazole: A single-center observational study

ObjectivePulmonary administration of voriconazole involves advantages, including optimization of lung penetration and reduction of adverse effects and interactions. However, there is scarce evidence about its use and there are no commercial presentations for nebulization. We aim to characterize a compounded voriconazole solution for nebulization and describe its use in our center. MethodThis is a retrospective observational study including patients who received nebulized voriconazole to treat fungal lung diseases (infection or colonization). Voriconazole solution was prepared from commercial vials for intravenous administration. ResultsThe pH and osmolarity of voriconazole solutions were adequate for nebulization. Ten patients were included, 9 adults and a child. The dosage was 40 mg in adults and 10 mg in the pediatric patient, diluted to a final concentration of 10 mg/ml, administered every 12–24 h. The median duration of treatment was 139 (range: 26–911) days. There were no reported adverse effects and the drug was not detected in plasma when nebulized only. ConclusionVoriconazole nebulization is well-tolerated and it is not absorbed into the systemic circulation; further research is needed to assess its efficacy.

Permeation kinetics of dimethyl sulfoxide in porcine corneoscleral discs

The cornea is the transparent tissue in front of the eye that bends light to help the eye focus. More than five million people's vision can be restored by a corneal transplant (keratoplasty), but there is a scarcity of suitable donor tissue. Cryopreservation could potentially increase the on-demand availability of corneas by reducing expiration and contamination during hypothermic storage, and allow equitable distribution. Understanding the transport of water and cryoprotectants across the tissue is important in developing effective cryopreservation protocols. Here, we first measured the shrinking and swelling kinetics at 22 °C and 0 °C of porcine corneoscleral discs when exposed to phosphate-buffered saline and to a cryoprotectant vehicle solution containing 2.5% chondroitin sulfate and 1% dextran. Other valuable measurements were made including the density and osmolality of the vehicle solution at 0 °C, and the water fraction of porcine cornea and sclera. Using the knowledge gained from this first part to minimize background swelling, we then examined permeation kinetics of dimethyl sulfoxide (Me2SO) in porcine corneoscleral discs at 0 °C, the temperature at which cryoprotectant loading typically occurs. The concentration data obtained as a function of time were fitted to a Fick's law model of one-dimensional diffusion to measure an effective diffusion coefficient of Me2SO, which was found to be 5.306×10−11 m2/s. We further quantified permeation kinetics of Me2SO in sclera alone at 0 °C to support our hypothesis that our measurements for corneoscleral discs will not be affected by the presence of the sclera. The obtained effective diffusion coefficient can be used in modelling aimed at developing cryopreservation protocols that minimize the exposure time of the corneas during the cryoprotectant loading step.

P-190 Spontaneous blastocyst collapse during pre-vitrification equilibration is related to a lower live birth rate: a prospective cohort study

Abstract Study question This report provides updated data from a study investigating the association between the spontaneous collapse patterns of blastocysts during pre-vitrification equilibration and pregnancy success. Summary answer Live birth rates were lower for completely collapsed blastocysts, suggesting the possibility for including blastocyst collapse pattern as a criterion for selecting embryos for transfer. What is known already Previous time-lapse studies have found that blastocysts exhibiting strong contraction during culture have a low probability of hatching in animals and implanting in humans, suggesting blastocyst contraction has a negative impact on reproductive outcomes. Conversely, artificial shrinkage of human blastocysts before vitrification is considered to improve embryo survival and/or pregnancy rates by promoting cryoprotectant permeation inside the blastocoel. However, shrinkage is not induced in some vitrification protocols, including ours, as the viability is high; this demonstrates the potential of existing protocols to achieve sufficient cryoprotectant permeation. Moreover, the Alpha consensus meeting on cryopreservation did not issue recommendations regarding artificial shrinkage. Study design, size, duration This study included 798 patients who were undergoing their first autologous IVF/ICSI cycle followed by a freeze-all strategy, including blastocyst vitrification, at our clinic between June 2018 and November 2021. For patients with multiple vitrified blastocysts, embryos for transfer were selected hierarchically based only on morphological scoring during culture. To reduce bias, only data from a single blastocyst (day 5, Gardner score 4, excluding CC) transfer from each patient’s first warmed cycle was analyzed. Participants/materials, setting, methods Blastocysts were vitrified-warmed in in-house-prepared solutions using Rapid-i carriers. Prior to vitrification, intact blastocysts were equilibrated in 10% ethylene glycol (15 min, 37 °C). Their spontaneous collapse patterns were assessed under an inverted microscope before they were vitrified in 15% ethylene glycol + 15% dimethylsulfoxide + 0.5 M sucrose. Blastocyst collapse was defined as the separation of the trophectoderm cells from the zona pellucida. Collapsed blastocysts with/without a blastocoel cavity were defined as partially/completely collapsed blastocysts. Main results and the role of chance Non-collapsed (Nc), partially collapsed (Pc), and completely collapsed (Cc) blastocyst transfers (embryo survival rate, 99.6%) constituted 27.1%, 54.6%, and 18.3% of the 798 cycles, respectively. Live birth rates differed significantly between groups (Nc, 54.2%; Pc, 46.6%; Cc, 34.2%; P &amp;lt; 0.001). Regarding perinatal outcomes of 366 singletons, the female rate tended to differ between groups (Nc, 35.3%; Pc, 44.3%; Cc, 53.1%; P = 0.084). Significant differences in maternal age (years: Nc, 34.6 ± 4.0; Pc, 35.4 ± 3.7; Cc, 36.4 ± 4.0; P &amp;lt; 0.001), MII oocyte number (Nc, 13.0 ± 6.2; Pc, 12.0 ± 6.6; Cc, 10.8 ± 6.9; P = 0.009), blastocyst diameter (μM: Nc, 184 ± 18; Pc, 181 ± 20; Cc, 173 ± 23; P &amp;lt; 0.001), and good-quality (4AA/4AB/4BA) blastocyst percentage (Nc, 70.4%; Pc, 61.2%; Cc, 47.9%; P &amp;lt; 0.001) were found between groups. Upon logistic regression analysis including these potential confounders, only maternal age (odds ratio (OR), 0.89; 95% confidence interval (CI), 0.86–0.93; P &amp;lt; 0.001) and collapse pattern (Cc/Nc: OR, 0.59; 95% CI, 0.37–0.93; P = 0.023) significantly impacted the live birth rate, whereas blastocyst morphology (good/not: OR, 1.37; 95% CI, 0.97–1.94; P = 0.069) tended to impact it. Limitations, reasons for caution The cryoprotectant concentration of our pre-vitrification equilibration solution is relatively low. Thus, caution is required when assessing the collapse pattern, as the solution osmolarity can influence blastocyst shrinkage. Follow-up studies with more participants are warranted to confirm these results and the health of the children born after vitrified-warmed embryo transfers. Wider implications of the findings A negative relationship was found between spontaneous blastocyst collapse during pre-vitrification equilibration and live birth rate. Studying blastocyst collapse pattern may assist selection of the most viable blastocysts after vitrification in ethylene glycol and dimethylsulfoxide—a widely used permeable cryoprotectant combination—thus, increasing IVF success rates. Trial registration number Not applicable

An educational game for teaching osmolarity and tonicity: opinions of dental and medical students.

In health courses, the students must be familiar with the effects of intravenous solutions on cell volume and function, a topic where there can be learning difficulties and misunderstandings. Since educational games can assist in understanding complex concepts, we created a game relating solution osmolarity and tonicity to red blood cell volume that was used in undergraduate Dentistry and Medicine courses. The students, working in groups, completed the game board by indicating the effect of the solutions on the red blood cell volume, classifying the solutions in terms of tonicity and osmolarity. The student indicated that use of the educational game contributed to their understanding of osmolarity and tonicity.

Effects of swelling and anatomical location on the viscoelastic behavior of the porcine urinary bladder wall

The ability of the urinary bladder to perform its physiological function depends largely on its mechanical characteristics. Understanding the mechanics of this tissue is crucial to the development of accurate models of not just this specific organ, but of the pelvic floor overall. In this study, we tested porcine bladder to identify variations in the tissue's viscoelastic characteristics associated with anatomical locations and swelling. We investigated this relationship using a series of stress-relaxation experiments as well as a modified Maxwell-Wiechert model to aid in the interpretation of the experimental data. Our results highlight that tissue located near the neck of the bladder presents significantly different viscoelastic characteristics than the body of the organ. This supports what was previously observed and is a valuable contribution to the understanding of the location-specific properties of the bladder. We also tested the effect of swelling, revealing that the bladder's viscoelastic behavior is mostly independent of solution osmolarity in hypoosmotic solutions, but the use of a hyperosmotic solution can significantly affect its behavior. This is significant, since several urinary tract pathologies can lead to chronic inflammation and disrupt the urothelial barrier causing increased urothelial permeability, thus subjecting the bladder wall to non-physiologic osmotic challenge.

Peripheral parenteral nutrition in surgery – a systematic review and meta-analysis

Peripheral parenteral nutrition (PPN) refers to the delivery of artificial nutrition via a peripheral intravenous cannula. As a nutritional intervention it remains under-utilised in peri-operative care. This is despite purported advantages which includes avoiding the risks associated with central venous lines and preventing potential delays to the initiation of nutrition support. This systematic review and meta-analysis will detail the available evidence for PPN use in surgery. A comprehensive search of the EMBASE and Medline databases was undertaken to identify randomised control trials (RCTs) involving PPN use in surgical patients published until July 30th 2022. Three domains of PPN use were reviewed including: PPN compared to crystalloid intravenous fluids on nutritional and clinical outcomes; PPN compared to Central PN (CPN) on nutritional outcomes and complications; and strategies to prevent thrombophlebitis associated with PPN. The meta-analysis included 8 studies which included 698 patients. Use of PPN led to reduced post-operative weight loss (% body weight change) with a mean difference of-1.45% (95% CI -2.9 to-0.01, p=0.05). There was no statistically significant difference in terms of length of stay, infectious/non-infectious complications, surgical site infections or phlebitis. 42 RCTs were included in the systematic review. 14 RCTs compared PPN to crystalloid infusion. There was significant heterogeneity in the trial populations, interventions and measured outcomes. Most trials found that PPN may improve nitrogen balance and positively impact nutritional markers. Quality of life and post-operative complications were either improved or no difference found in trials assessing these outcomes. Four RCTs showed that PPN is a safe and feasible alternative to CPN. 22 RCTs reported on measures that may impact on thrombophlebitis rates associated with PPN. These included lower osmolality of PPN solution, cyclical PPN delivery, use of a small gauge polyurethane cannula in an upper limb vein, addition of heparin/hydrocortisone to PPN solutions and placement of a GTN patch over infusion sites. PPN is a safe and effective mode of delivery of peri-operative nutrition. It is a feasible short-term alternative to central-line delivered PN. There are a number of strategies to reduce thrombophlebitis associated with PPN use. Further high-quality RCTs are required to assess the use of PPN in contemporary surgical practice.

Formulation and stability study of an oral paediatric phenobarbital 1% solution containing hydroxypropyl-β-cyclodextrins

ObjectivesPhenobarbital is a barbiturate, used to treat focal and generalised epilepsy. Since the end of marketing of the oral solution KANEURON in 2017, phenobarbital tablets remain the only available dosage...

Assessment of the relevance of osmolality measurement as a criterion for the stability of solutions

Abstract Objectives The measurement of osmolality is used by many authors as an additional stability criterion of a drug in solution. In the current state of knowledge, no scientific publication correlates the osmolality values and the stability of a solution. To study the relevance of this analytical technique by measuring the osmolality of injectable solutions whose instability has been chemically demonstrated by high performance liquid chromatography (HPLC). Methods Selection of 13 drug preparations whose chemical instability has been demonstrated in the literature. Realization of three identical samples per selected preparation and measurements of the osmolality of the freshly prepared solutions, then, at various storage times until a chemical degradation of the molecule validated by HPLC of at least 10% and possibly up to 40%. Results Measurements of the osmolality were performed on five antibiotics (amoxicillin/clavulanic acid, cefepime, cefoxitine, meropenem and temocillin and cefoxitin) and five anticancer drugs (azacitidine, bendamustine, busulfan, fotemustine and oxaliplatin). Osmolality varied from −6.30 to 11.10% for antibiotics and from 0.57 to 2.04%. Conclusions Among the preparations tested, only two formulations have a variation in osmolality in accordance with the chemical degradation. For the other 11 formulas, the variations in osmolality values where not correlated with the degradation measured by HPLC. In view of these results, osmolality does not seem to be a criterion of choice for the study of drug stability. In the majority of the unstable solutions studied, the variation of osmolality measurements does not correlate with the loss of concentration and the appearance of degradation products.