Prevalence and risk factors of hyponatremia in hospitalized critically ill children: an observational study.

Critically ill children frequently encounter the most common and potentially life-threatening electrolyte disturbances, i.e., hyponatremia. It is an independent risk factor for prolonged hospitalization in the intensive care unit and increased in-hospital mortality. Hyponatremia occurs in up to 20%-30% of admissions in the pediatric intensive care unit (PICU). This observational study was conducted in the PICU of a tertiary care hospital in a developing country from September 2018 to September 2019. Admission criteria in our PICU are the need for mechanical ventilation, fulminant hepatic failure, vasopressor support, respiratory failure and poorly controlled seizure. We studied 256 children, aged 1 month to 18 years, with normal serum sodium at admission. In our study, 72 (28.1%) children developed hyponatremia, and about two third (n=48, 66.7%) of them developed within 72 hours of admission in PICU. The majority of children (n = 46, 63.9%) in the hyponatremic group were below 5 years. Wasted children (n = 68, 26.6%) in the hyponatremic and isonatremic groups were 20 (27.8%) and 48 (26%), respectively. The most common etiology of hyponatremia was cerebral salt wasting syndrome (n = 20, 27.8%) followed by drug-induced cases (n = 19, 26.4%). The drugs responsible were diuretics and anti-epileptics. In our study, multiorgan failure (OR = 5.05, 95%CI = 1.90-13.43; p = 0.0001), shock (OR = 7.38, 95%CI = 3.56-12.28; p = 0.0001), vasopressor use (OR = 6.74, 95%CI = 3.45-13.17; p = 0.0001) and coagulopathy (OR = 6.74, 95%CI = 3.45-13.17; p = 0.0001) were the risk factors for the development of hyponatremia. Mortality among the hyponatremic group (44.4%) was significantly higher than in the isonatremic group (21.7%). Hyponatremia is a common electrolyte disturbance found in critically ill patients and is associated with prolonged hospitalization and increased mortality.

Isolated Bilateral Upper Limb Amelia - A Rare Case Report.

Introduction: Congenital upper limb amelia is one of the extremely rare conditions. It is defined as a complete absence of upper limbs. It may present as isolated or with other associated anomalies. Case Report: We present a case of a 2-year-old male child with congenital complete absence of bilateral upper limb. This male child was born after four female children. With the advancement in modern-era prenatal diagnostic facilities and a better understanding of fetal-maternal drug pharmacology, such cases are rare entity. Conclusion: Amelia is a very rare and challenging situation for clinicians. Regular prenatal checkup and knowledge of maternal and fetal drug interactions during pregnancy are key factors for prevention.

Crustwater: Modeling Hydrophobic Solvation.

We describe Crustwater, a statistical mechanical model of nonpolar solvation in water. It treats bulk water using the Cage Water model and introduces a crust, i.e., a solvation shell of coordinated partially structured waters. Crustwater is analytical and fast to compute. We compute here solvation vs temperature over the liquid range, and vs pressure and solute size. Its thermal predictions are as accurate as much more costly explicit models such as TIP4P/2005. This modeling gives new insights into the hydrophobic effect: (1) that oil-water insolubility in cold water is due to solute-water (SW) translational entropy and not water-water (WW) orientations, even while hot water is dominated by WW cage breaking, and (2) that a size transition at the Angstrom scale, not the nanometer scale, takes place as previously predicted.

Calcium Ion Binding to the Mutants of Calmodulin: A Structure-Based Computational Predictive Model of Binding Affinity Using a Charge Scaling Approach in Molecular Dynamics Simulation.

The binding of calcium ions (Ca2+) to the calcium-binding proteins (CBPs) controls a plethora of regulatory processes. Among the roles played by CBPs in several diseases, the onset and progress of some cardiovascular diseases are caused by mutations in calmodulin (CaM), an important member of CBPs. Rationalization and prediction of the binding affinity of Ca2+ ions to the CaM can play important roles in understanding the origin of cardiovascular diseases. However, there is no robust structure-based computational method for predicting the binding affinity of Ca2+ ions to the different forms of CBPs in general and CaM in particular. In the current work, we have devised a fast yet accurate computational technique to accurately calculate the binding affinity of Ca2+ to the different forms of CaM. This method combines the well-known molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) method and a charge scaling approach developed by previous authors that takes care of the polarization of CaM and Ca2+ ions. Our detailed analysis of the different components of binding free energy shows that subtle changes in electrostatics and van der Waals contribute to the difference in the binding affinity of mutants from that of the wild type (WT), and the charge scaling approach is superior in calculating these subtle changes in electrostatics as compared to the nonpolarizable force field used in this work. A statistically significant regression model made from our binding free energy calculations gives a correlation coefficient close to 0.8 to the experimental results. This structure-based predictive model can open up a new strategy to understand and predict the binding of Ca2+ to the mutants of CBPs, in general.

Analytical 2-Dimensional Model of Nonpolar and Ionic Solvation in Water.

A goal in computational chemistry is computing hydration free energies of nonpolar and charged solutes accurately, but with much greater computational speeds than in today's explicit-water simulations. Here, we take one step in that direction: a simple model of solvating waters that is analytical and thus essentially instantaneous to compute. Each water molecule is a 2-dimensional dipolar hydrogen-bonding disk that interacts around small circular solutes with different nonpolar and charge interactions. The model gives good qualitative agreement with experiments. As a function of the solute radius, it gives the solvation free energy, enthalpy and entropy as a function of temperature for the inert gas series Ne, Ar, Kr, and Xe. For anions and cations, it captures relatively well the trends versus ion radius. This approach should be readily generalizable to three dimensions.