Suitability of Steric Mass-action Model for Ion-exchange Equilibrium of Micromolecule

The steric mass-action (SMA) model has been widely reported in the literature for ion-exchange and metal-affinity interaction adsorption equilibrium of biomacromolecules. In this paper, the usefulness of SMA model is analyzed for describing micromolecule ion-exchange equilibrium onto cation exchangers, CM Sephadex C-25 and Streamline SP. Batch adsorption experiments with ephedrine hydrochloride as a model adsorbate are carried out to determine the model parameters, that is, steric factor, characteristic charge and equilibrium constant. The result shows that the SMA model parameters of micromolecule cannot be obtained using the nonlinear least-square fitting method as protein's due to the remarkable difference between the molecular mass and dimension of micromolecule and protein. It is considered that the small size of the adsorbates dealt with in this study justifies the neglect of steric hindrances arising from adsorbate bulkiness. Thus, the three-parameter SMA model is reduced to two-parameter one (i.e., steric factor is equal to zero) for describing micromolecule ion-exchange equilibrium. It is found that the equilibrium constant for CM Sephadex C-25 increases with increasing ionic strength, while the equilibrium constant for Streamline SP shows an opposite trend. This is probably due to the remarkable difference between the physicalpro perties of the two adsorbents. Then, the relationship between the equilibrium constant and ionic strength is described by an expression. The computer simulations show that, the theoretical model with the correlation is promising in the prediction of micromolecule adsorption decrease with increasing ionic strength in a wide range of salt concentration.

Mesenchymal Stem Cells—A Boon to Orthopedics

Percutaneous administration of “Orthobiologics” offers the advantage of accelerated and functional recovery of musculoskeletal disorders. Stem cell optimizes the biological healing of diseases. The regenerative capacity of mesenchymal stem cells provides a pavement for clinicians to build up an organ of interest in vitro. Mesenchymal stem cells remain the perfect cell based tissue regeneration modality for treatment of musculoskeletal disorders in a minimally invasive environment without any significant morbidity. This article outlines the applications of mesenchymal stem cell administration in various musculoskeletal disorders.

Analysis of Cordyceps by multi-column liquid chromatography

Cordyceps is a famous traditional Chinese medicine (TCM) that has been used in China for hundreds of years. In the present study a multi-column liquid chromatography (MC-LC) system was developed for the qualitative analysis of macromolecules and micromolecules in Cordyceps. The MC-LC system includes a size exclusion pre-column, a size exclusion column (SEC) and a reversed phase column (RP) which were controlled by column-switching valves. The sample was separated by the size exclusion pre-column into two fractions (macromolecules and micromolecules). These fractions were further separated on SEC and RP columns, respectively. A diode array detector (DAD) and a mass spectrometer (MS) were used to detect the components. This MC-LC method was utilized for analysis of Cordyceps samples. Two macromolecular peaks and 15 micromolecular peaks were found in Cordyceps, and 11 of the micromolecular peaks were identified as adenosine-5'-monophosphate (AMP), phenylalanine, uridine, hypoxanthine, inosine, guanine, guanosine, deoxyadenosine-5'-monophosphate (dAMP), adenosine, adenine and cordycepin (or its isomer). This method is useful for quality control of Cordyceps. (C) 2017 Chinese Pharmaceutical Association and Institute of Materia Medica, Chinese Academy of Medical Sciences. Production and hosting by Elsevier B.V.