Dysnatremia in Traumatic Brain Injury and its Association with Outcome.

Background Traumatic brain injury on its own results in significant mortality and morbidity but it also contributes to complications that manifest as dysnatremia in the majority of cases. Objective The objective of this study is to assess the association of hyponatremia and hypernatremia with the severity of traumatic brain injury and its impact on mortality. Method This is a retrospective, descriptive, and analytic study conducted during a 1-year period from March 2018 to March 2019. The study population was selected from the patients presenting to the emergency department with TBI in the Upendra Devkota Memorial National Institute of Neurological and Allied Sciences, Bansbari, Kathmandu, Nepal. All the patients that fulfilled the inclusion criteria of age were enrolled in the study. Patients with known renal disease due to the higher incidence of electrolyte disbalance were excluded. Association of outcome with hyponatremia and hypernatremia were sought using chi-square, fisher exact test and independent t test using SPSS ver 20. Result Over a period of 1 year, 367 patients with traumatic brain injuries were treated in our hospital. Hyponatremia was seen among 55 patients (14.9%) and hypernatremia was seen among 22 patients (5.99%). The age range of patients included in the study was 16 to 87 with a mean age of 37.96 ± 16.512 years. The male to female ratio was calculated as 3.2:1. Mild, moderate, and severe head injuries were 286 (77.9%), 37 (10.1%), and 44 (12%) respectively. Surgical intervention was performed among 77(21%) individuals. Our series showed an association between the severity of traumatic brain injury and hyponatremia however didn't show an association between the severity of traumatic brain injury and the development of hypernatremia. Conclusion We concluded that the severity of head injury is associated with severity of hyponatremia but not with severity of hypernatremia. Similarly, a strong association existed between the severity of hypernatremia and outcome of patients. However, such association was not seen with hyponatremia.

Urea effect on aggregation and adsorption of sodium dioctylsulfosuccinate in water.

Understanding the mechanism that controls the folding/unfolding of proteins in the presence of urea continues to be a subject of research, and since micelles mimic biological aggregates, equal importance has been given to the study of surfactants in the presence of urea. Despite several studies on the effect of urea on the behavior of reverse micelles and microemulsions based on sodium dioctylsulfosuccinate (AOT), the urea effect on AOT regular micelles has not been investigated and hence it is studied herein by using surface tension, steady-state fluorescence, and dynamic light scattering methods. The effect of urea on the behavior of AOT is found to be different below and above 1.0 mol kg(-1) urea (c(u)). The critical micelle concentration (cmc) is almost independent of urea concentration below c(u), whereas it increases with increasing urea amount above c(u). In AOT+urea aqueous solution below c(u), added NaCl at a particular critical concentration (c*) induces sudden increase in the values of (i) counterion binding constant, (ii) aggregation number, (iii) fluorescence intensity ratio of pyrene excimer to monomer, and (iv) hydrodynamic diameter of AOT aggregate, whereas such changes are suppressed by urea above c(u). NaCl-induced shape change in AOT micelle takes place if urea concentration is below c(u), but hindered above c(u). The adsorption behavior of AOT at the air-solution interface as a function of NaCl is also found to be different below and above c(u). The urea effect is explained in terms of increase in the polarity of the medium, better solvation of head groups and counterions, and weakening of head group-head group and head group-counterion interactions.

Aggregation behavior of sodium dioctylsulfosuccinate in aqueous ethylene glycol medium. A case of hydrogen bonding between surfactant and solvent and its manifestation in the surface tension isotherm.

The dependence of critical micelle concentration (cmc) of sodium dioctylsulfosuccinate (AOT) on the amount of ethylene glycol (EG) in water + EG medium was reported to be unusual and different from that of other surfactants to the extent that the cmc of AOT in EG is lower than in water. It is yet to be understood why AOT behaves so in water + EG medium, although AOT is known to have some special properties. Hence in the present study cmc of AOT in water + EG medium in the range from 0 to 100% (by weight) EG is measured by using surface tension and fluorescence emission methods. In contrast to what was reported, this study revealed that with respect to EG amount the cmc of AOT follows the general trend and AOT has higher cmc in EG than in water. On the other hand, it was surprisingly found that a break in the surface tension isotherm occurs in the premicellar region when the amount of EG exceeds 50% rendering a bisigmoidal shape to the surface tension isotherm. UV spectral study showed that AOT and EG undergo hydrogen bonding in the premicellar region when the EG amount is ≥50% and this hydrogen bonding becomes less on adding NaCl. The density functional theory calculations also showed formation of hydrogen bonds between EG and AOT through the sulfonate group of AOT providing thereby support to the experimental findings. The calculations predicted a highly stable AOT-EG-H(2)O trimer complex with a binding energy of -37.93 kcal mol(-1). The present system is an example, which is first of its kind, of a case where hydrogen bonding with surfactant and solvent molecules results in a surface tension break.

Aggregation and adsorption of sodium dioctylsulfosuccinate in aqueous ammonium chloride solution: role of mixed counterions.

The critical micelle concentration (cmc) of sodium dioctylsulfosuccinate (AOT) was determined at 25 °C from surface tension and fluorescence methods in aqueous NH(4)Cl solution for assessing the influence of mixed counterions on the special counterion binding behavior (SCB) of AOT. The SCB of AOT refers to a sudden twofold increase in the value of the counterion binding constant (ß) in aqueous medium when the concentration (c(*)) of the added 1:1 sodium salt is about 0.015 mol kg(-1), and it has been tested so far for sodium ion only. In the presence of sodium and ammonium mixed counterions also the SCB of AOT exist, but with lower c(*) (0.009 mol kg(-1) NH(4)Cl). Synergism in the cmc occurs due to mixed counterions. In the case of inorganic counterions, unlike the case with organic counterions, the cmc is dependent on the total counterion concentration in solution and negligibly on the specific type of counterion. Na(+) and NH(4)(+) bind almost equally to the micelle in the region of low ß (below c(*)), but in the region of high ß (above c(*)) NH(4)(+) binds predominantly. It has been shown that the theoretical expression for the surface excess of ionic surfactant+electrolyte system containing a single counterion can also be used to evaluate the surface excess in the presence of mixed counterions if the two counterions are considered to undergo Henry-type adsorption at the air-solution interface.