Modelling drug elution from stents: effects of reversible binding in the vascular wall and degradable polymeric matrix

Today the most popular approach for the prevention of the restenosis consists in the use of the drug eluting stents. The stent acts as a source of drug, from a coating or from a reservoir, which is transported into and through the artery wall. In this study, the behaviour of a model of a hydrophilic drug (heparin) released from a coronary stent into the arterial wall is investigated. The presence of the specific binding site action is modelled using a reversible chemical reaction that explains the prolonged presence of drug in the vascular tissue. An axi-symmetric model of a single stent strut is considered. First an advection–diffusion problem is solved using the finite element method. Then a simplified model with diffusion only in the arterial wall is compared with: (i) a model including the presence of reversible binding sites in the vascular wall and (ii) a model featuring a drug reservoir made of a degradable polymeric matrix. The results show that the inclusion of a reversible binding for the drug leads to delayed release curves and that the polymer erosion affects the drug release showing a quicker elution of the drug from the stent.     

Computer-Intensive Statistical Procedures

The overall goal of this review is to summarize the current body of knowledge about the structure and function of major proteins of Bacillus anthracis and/or similar spore-forming organisms. B. anthracis is a key spore-forming biological threat agent, as well as human and animal Gram-positive bacterial pathogen. The structural information described here is limited to approximately the last 5 years. This information is then related to the role of the selected proteins in pathogenesis and in the possible development of novel vaccine and/or other antimicrobial agents against spore-forming organisms, including anthrax, a disease caused by B. anthracis.

Among spore-forming bacteria, Bacillus and Clostridium species are the predominant spore-forming bacilli that cause serious diseases. The biochemical properties and mechanism of catalysis of the novel spore germination protease that degrades small, acid-soluble proteins protecting DNA against damage, a cofactor independent phosphoglycerate mutase, NAD⁺ synthetase, and the three know B. anthracis toxins, protective antigen, lethal factor, and edema factor are described. The studies described in this work review and unify selected information critical for the prevention of microbial diseases such as anthrax. A strategy for the structure-guided development of new prophylactic and therapeutic agents is discussed.     

Chinese plasma-derived products supply under the lot release management system in 2007–2011

In 2007, the Chinese State Food and Drug Administration (SFDA) implemented a management system for lot release of all plasma-derived products. Since then, there have been only a few systematic studies of the blood supply, which is a concern when considering the small amount of plasma collected per capita (approximately 3 L/1000 people). As a result, there may be a threat to the safety of the available blood supply. In this study, we examined the characteristics of the supply of Chinese plasma-derived products. We investigated the reports of lot-released biological products derived from all 8 national or regional regulatory authorities in China from 2007 to 2011. The market supply characteristics of Chinese plasma-derived products were analyzed by reviewing the changes in supply varieties, the batches of lot-released plasma-derived products and the actual supply. As a result, the national regulatory authorities can more accurately develop a specific understanding of the production and quality management information provided by Chinese plasma product manufacturers. The implementation of the lot release system further ensures the clinical validity of the plasma-derived products in China and improves the safety of using plasma-derived products. This work provides an assessment of the future Chinese market supply of plasma-derived products and can function as a theoretical basis for the establishment of hemovigilance.     

Joseph Rudinger memorial lecture: Discovery and applications of cyclotides

Cyclotides are plant‐derived peptides of approximately 30 amino acids that have the characteristic structural features of a head‐to‐tail cyclized backbone and a cystine knot arrangement of their three conserved disulfide bonds. This article gives a personal account of the discovery of cyclotides, their characterization and their applications, based on work carried out in my laboratory over the last 20 years. It describes some of the background to their discovery and focuses on how their unique structural features lead to exceptional stability. This stability and their amenability to chemical synthesis have made it possible to use cyclotides as templates in protein engineering and drug design applications. These applications complement the interest in cyclotides deriving from their unique structures and natural function as host defense molecules. Copyright © 2013 European Peptide Society and John Wiley & Sons, Ltd.     

Interrogating 7TM receptors: Does texture in the question yield greater texture in the answer?

The key to detecting and classifying drug effect at seven transmembrane (7TM) receptors is the pharmacological assay. Drug discovery had been rooted in testing of molecules on intact animal tissue until technology provided high-throughput binding assays for screening. While this allowed for the testing of large numbers of molecules, it also limited detection to molecules that interfere with the interaction of the receptor with a defined probe (i.e., radioligand). The ability to monitor functional changes in cells (recombinant or natural) provided a huge leap forward. Earlier functional assays were tied to specific signaling pathways (i.e., cyclic AMP and calcium) but now label-free assays in live cells provide the opportunity to detect more ligands and more fully characterize their efficacy. These ideas will be discussed in terms of harnessing the phenomenon of “functional selectivity” for therapeutic advantage.     

Design,synthesis and preliminary activity evaluation of novel 3-amino-2-hydroxyl-3-phenylpropanoic acid derivatives as aminopeptidase N/CD13 inhibitors

Aminopeptidase N (APN/CD13) over expressed on tumour cells, plays a critical role in tumour invasion, metastasis and tumour angiogenesis. In this article, we described the design, synthesis and preliminary activity studies of novel 3-amino-2-hydroxyl-3-phenylpropanoic acid derivatives as APN inhibitors. The in vitro enzymatic inhibitions on APN from porcine kidney showed that compound 7e had the most potent inhibitory activity against APN with the IC₅₀ value to 1.26?±?0.01 μM, which is better than that of bestatin (IC₅₀?=?2.55?±?0.11 μM). In addition, compound 7e also showed better inhibitory activity against APN on human ovary clear cell carcinoma cell ES-2 than bestatin with the IC₅₀ value to 30.19?±?1.02 μM versus 60.61?±?0.1 μM. Compound 7e could be used as the lead compound in the future for anti-cancer agent research.     

Physicochemical characterization of an aspin (rBm-33) from a filarial parasite Brugia malayi against the important human aspartic proteases

The aspartic protease inhibitory efficiency of rBm-33, an aspin from a filarial parasite Brugia malayi was investigated. rBm-33 was found to be thermostable up to 90°C and it forms a stable ‘enzyme-product’ complex with human pepsin. Aspartic protease inhibitory activity was investigated using UV spectroscopy and isothermal titration calorimetry. Our results suggest that rBm-33 inhibits the activity of important human aspartic proteases that were examined with binding constants (K_b) values between 10.23?×?10³ and 6.52?×?10³ M^?1. The binding reactions were enthalpy driven with ΔH_b values between ?50.99 and ?46.07 kJ mol^?1. From kinetic studies, pepsin inhibition by rBm-33 was found to be linear competitive with an inhibition constant (Ki) of 2.5 (±0.8) nM. Because of the inhibitory efficacy of Bm-33 against important human aspartic proteases which play a vital role in immune-regulation along with other functions, Bm-33 can be projected as a drug target for the filariasis.     

Effects of some drugs on the activity of glucose 6-phosphate dehydrogenase from rainbow trout (Oncorhynchus mykiss) erythrocytes in vitro

Inhibitory effects of some drugs on glucose 6-phosphate dehydrogenase from the erythrocytes of rainbow trout (Oncorhynchus mykiss Walbaum, 1792) were investigated. The enzyme was purified 2488-fold in a yield of 76.8% using ammonium sulfate precipitation and 2′,5′-ADP Sepharose 4B affinity gel at 4°C. The drugs pental sodium, MgSO₄, vancomycin, metamizol, marcaine, and prilocaine all exhibited inhibitory effects on the enzyme. While MgSO₄ (K_i = 12.119 mM), vancomycin (K_i = 1.466 mM) and metamizol (K_i = 0.392 mM) showed competitive inhibition, pental sodium (K_i = 0.748 mM) and marcaine (K_i = 0.0446 mM) displayed noncompetitive inhibition.