Biological Effects Of Molecules Research Articles

Ex Vivo Normothermic Hypoxic Rat Liver Perfusion Model: An Experimental Setting for Organ Recondition and Pharmacological Intervention.

The gold standard for organ preservation before transplantation is static cold storage, which is unable to fully protect suboptimal livers from ischemia/reperfusion injury. An emerging alternative is normothermic machine perfusion (NMP), which permits organ reconditioning. The ex vivo NMP hypoxic Rat Liver Perfusion Model represents a feasible approach that allow pharmacological intervention on isolated rat livers by using a combination of NMP and infusion of a number of drugs and/or biological material (cells, microvesicles, etc.). The combination of these two techniques may not only be applied for tissue preservation purposes, but also to investigate the biological effects of molecules and treatment useful in tissue protection. The protocol describes an ex vivo murine model of NMP capable of maintaining liver function despite an ongoing hypoxic injury induced by hemodilution. Furthermore, with this NMP system it is possible to deliver cells treatment or pharmacological intervention to an ex vivo perfused liver and suggests that could represent an innovative approach to recondition organs.

Effects of Biological Molecules on Calcium Mineral Formation Associated with Wastewater Desalination as Assessed using Small-Angle Neutron Scattering

Calcium phosphate scale formation on reverse osmosis (RO) membranes is one of the main limitations on cost-effective desalination of domestic wastewater worldwide. It has been shown that organic agents affect mineralization. In this study, we explored mineralization in the presence of two biofilm-relevant organic compounds, the proteins bovine serum albumin (BSA) and lysozyme, in a simulated secondary effluent (SSE) solution using small-angle neutron scattering (SANS), and applied the results to analyses of mineral precipitation in RO desalination of secondary effluents of wastewater. The two proteins are prominent members of bacterial extracellular polymeric substances (EPSs), forming biofilms that are frequently associated with RO-membrane fouling during wastewater desalination. Laboratory experiments showed that both proteins in SSE solution are involved in complex mineralization processes. Only small portions of both protein fractions are involved in mineralization processes, whereas most of the protein fractions remain as monomers in solution. Contrast variation showed that composite particles of mineral and protein are formed instantaneously to a radius of gyration of about 300 Å, coexisting with particles of about μm size. After about one day, these large particles start to grow again at the expense of the 300 Å particles. The volume fraction of the 300 Å particles is of the order of 2 × 10(-4), which is too large to represent calcium phosphate such as hydroxyapatite as the only mineral present. Considering the data of mineral volume fraction obtained here as well as the solubility product of possible mineral polymorphs in the SSE solution, we suggest the formation of protein-mineral particles of hydroxyapatite and calcium carbonate during scale formation.

Application of Quantum Chemistry to Drugs and Their Interactions

Whether or not quantum mechanics is the supreme intellectual accomplishment of man-an allegation that appears less of a conceit as one reads its history (1-3)­ it has certainly fostered philosophical speculation ( I , 4-7) and a great deal of very practical achievements. It is reassuring to learn that quantum mechanics does not exclude life (8) and at the same time that it can account for laboratory observations that otherwise elude explanation. Molecular orbital (MO) methods, which have been more widely applied than the other m ethod of quantum m echanics (the va­ lence-bond or resonance method), have explained many of the physical and chemical properties of molecules of interest to the chemist (9-15). Evidence is accumulating that MO methods can also explain the physical and chemical properties of large biomolecules and, by inference, their biological activities (16-18). The relative ioni­ zation potentials and dipole moments of a series of purines (18, 19) were consistent with those predicted ten years earlier in the Pullmans' laboratory by MO theory. MO calculations on biomolecules have yielded information in agreement with that obtained by nuclear magnetic resonance spectroscopy (20--23), infrared spectros­ copy (20), X-ray diffraction analysis (21, 24, 25) and, reasonably, with circular dichroic spectra (26). In most of this work, the results of the calculations have clear biological implications even to enzymatic m echanisms (16, 17, 27-32). Many of the inferences from MO calculations have been supported by subsequent experiment, a surprising number in consideration of the simple methods available when this work began and the inherent shortcomings of even modern MO techniques. Despite these successes in accounting for the biological properties of molecules, there has been m uch less effort to use quantum-mechanical m ethods to account for the biological effects of molecules. This relative lack is strange, because the first application of quantum mechanics in biology was to analyze carcinogenic hydrocar-