Chiral separation-based ligand exchange by open-tubular capillary electrochromatography

Chiral ligand-exchange enantioseparation of aliphatic and aromatic amino acids was successfully performed using a new open-tubular zwitterionic column with tentacle-type polymer stationary phase. The polymeric stationary phase was prepared using 3-chloro-2-hydroxypropyl methacrylate (HPMA-Cl), a new reactive monomer. The preparation procedure of the open-tubular column included silanization, in situ graft polymerization with HPMA-Cl, and l-histidine (l-His) modification. l-His was used as a chiral ligand-exchange selector and copper(II) as a central ion. Successful enantioseparation of six pairs of amino acid enantiomers was achieved with a buffer of 5 mM CuSO₄, 20 mM (NH₄)₂SO₄ at pH 3.0.     

Effects of clothianidin exposure on sperm quality,testicular apoptosis and fatty acid composition in developing male rats

Clothianidin (CTD) is one of the latest members of the synthetic organic insecticides, the neonicotinoids. In the present study, it was aimed to investigate if daily oral administration of CTD at low doses for 90 days has any deleterious effects on reproductive functions of developing male rats. Animals were randomly divided into four groups of six rats each, assigned as control rats, or rats treated with 2 (CTD-2), 8 (CTD-8) or 32 (CTD-32) mg CTD/kg body weight by oral gavage. The significant decreases of the absolute weights of right cauda epididymis and seminal vesicles, and body weight were detected in the animals exposed to CTD administration at 32 mg/kgBW/day. Epididymal sperm concentration decreased significantly in CTD-32 group and the abnormal sperm rates increased in CTD-8 and CTD-32 groups when compared to control group. The testosterone level was significantly decreased in CTD-32 group when compared to control group. The administration of all CTD doses resulted in a significant decrease in the level of GSH. The number of TUNEL-positive cells significantly increased in the germinal epithelium of testis of rats exposed to CTD at 32 mg/kgBW/day. In groups CTD-8 and CTD-32, only docosapentaenoic, arachidonic, palmitic and palmitoleic acids were significantly elevated when compared to control. The ratios of 20:4/18:2 and 18:1n−9/18:0 were decreased when rats exposed to CTD. Sperm DNA fragmentation was observed in CTD-32 group, but not CTD-2 and CTD-8. It is concluded that low doses of CTD exposure during critical stages of sexual maturation had moderate detrimental effects on reproductive organ system and more severe effects are likely to be observed at higher dose levels. In addition, the reproductive system may be more sensitive to exposure of CTD even earlier in development (prenatal and early postnatal), and therefore it could be expected that more severe effects could also be observed at the NOAEL dose levels, if dosing had occurred in utero or early postnatal.     

Synthesis,Cancer‐Selective Antiproliferative and Apoptotic Effects of Some (±)‐Naringenin Cycloaminoethyl Derivatives

Naringenin is a naturally occurring flavonoid and due to its broad spectrum of biological activities, including anticancer properties, has attracted scientific attention in recent years. To contribute to these studies, we synthesized some new (±)‐naringenin cyclic aminoethyl derivatives, analyzed the cytotoxic and anti‐proliferative properties of them via 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐2H‐tetrazolium bromide (MTT) assay, and mitochondrial apoptosis signaling response and gene expressions belong to caspase‐3 depended apoptosis as biomarkers in both healthy and cancer cell lines. Our results suggest that some of our naringenin derivatives are potential anticancer agents with a selective death potential and targeting properties for mitochondrial apoptosis signaling against at least human cervix and breast cancer.     

Evaluation of Essential and Toxic Trace Elements in Pseudoexfoliation Syndrome and Pseudoexfoliation Glaucoma

Pseudoexfoliation syndrome (PEX), an age-related disorder of the eye, is associated with significant ophthalmic morbidity and can lead to pseudoexfoliation glaucoma (PEG). The etiology of this disorder has not been clearly understood. Trace elements have been suggested to have roles in the pathogenesis of several disorders. This study aimed to determine whether trace element levels have a role in the development of PEX and/or PEG. Levels of zinc (Zn), copper (Cu), selenium (Se), manganese (Mn), chromium (Cr), cobalt (Co), molybdenum (Mo), nickel (Ni), vanadium (V), arsenic (As), aluminum (Al), mercury (Hg), cadmium (Cd), and strontium (Sr) were determined in serum samples of 32 cases of PEX, 30 cases of PEG, and 32 control subjects using inductively coupled plasma–mass spectrometry. Mn, Mo, and Hg concentrations were found to be significantly increased in patients with PEX. Logistic regression revealed Mn and Hg as the strongest determinants of PEX and Mo as the strongest determinant of PEG in the studied Turkish subjects. Levels of Mn, Cr, Co, Mo, Al, Hg, Sr, Ni, V, and As were determined for the first time in these ophthalmological disorders. Increased levels of serum Mn, Mo, and Hg suggest a possible role of these elements in the pathobiology of PEX.     

Brain electrical activities of dancers and fast ball sports athletes are different

Exercise training has been shown not only to influence physical fitness positively but also cognition in healthy and impaired populations. However, some particular exercise types, even though comparable based on physical efforts, have distinct cognitive and sensorimotor features. In this study, the effects of different types of exercise, such as fast ball sports and dance training, on brain electrical activity were investigated. Electroencephalography (EEG) scans were recorded in professional dancer, professional fast ball sports athlete (FBSA) and healthy control volunteer groups consisting of twelve subjects each. In FBSA, power of delta and theta frequency activities of EEG was significantly higher than those of the dancers and the controls. Conversely, dancers had significantly higher amplitudes in alpha and beta bands compared to FBSA and significantly higher amplitudes in the alpha band in comparison with controls. The results suggest that cognitive features of physical training can be reflected in resting brain electrical oscillations. The differences in resting brain electrical oscillations between the dancers and the FBSA can be the result of innate network differences determining the talents and/or plastic changes induced by physical training.     

Preparation and characterisation of surfaces properties of poly(hydroxyethylmethacrylate-co-methacrylolyamido-histidine) membranes: application for purification of human immunoglobulin G

In this study, an affinity membrane containing L-histidine as an amino acid ligand was used in separation and purification of human immunoglobulin G (HIgG) from solution and human serum. The polarities and the surface free energies of the affinity membranes were determined by contact angle measurements. HIgG adsorption and purification onto the affinity membranes from aqueous solution and human serum were investigated in a batch and a continuous system. Effect of different system parameters such as ligand density, adsorbent dosage, pH, temperature, ionic strength and HIgG initial concentration on HIgG adsorption were investigated. The maximum adsorption capacity of p(HEMA-MAAH-4) membranes for HIgG was 13.06 mgml(-1). The reversible HIgG adsorption on the affinity membrane obeyed both the Langmuir and Freundlich isotherm models. The adsorption data was analysed using the first- and second-order kinetic model and the experimental data was well described by the first-order equations. In the continuous system, the purity of the eluted HIgG, as determined by HPLC, was 93% with recovery 58% for p(HEMA-MAAH-4) membrane. The affinity membranes are stable when subjected to sanitization with sodium hydroxide after repeated adsorption-elution cycles.     

Conformational dynamics of subtilisin-chymotrypsin inhibitor 2 complex by coarse-grained simulations

An off-lattice dynamic Monte Carlo (MC) method is used to investigate the conformational dynamics of chymotrypsin inhibitor 2 (CI2) and subtilisin in both free and complex forms over two time windows, referring to short and long time scales. The conformational dynamics of backbone bonds analysed from several independent trajectories reveal that: Both the inhibitor and the enzyme are restricted in their bond rotations, excluding a few bonds, upon binding; the effect being greatest for the loop regions, and for the inhibitor. A cooperativity in the near-neighbor bond rotations are observed on both time scales, whereas the cooperative rotations of the bonds far along the sequence appear only in the long time window, and the latter time window is where most of the interactions between the inhibitor and the enzyme are observed. Upon binding, the cooperatively rotating parts of the inhibitor and the enzyme are readjusted compared to their free forms, and new correlations appear. The binding loop, although it is the closest contact region, is not the only part of the inhibitor involved in the interactions with the enzyme. Loops 3 and 8 and the helices F and G in bound enzyme and the binding loop of the inhibitor contribute at the most to the collective motions of whole structure on the slow time scale and are apparently important for enzyme-inhibitor interactions and function. The results in general provide evidence for the contribution of the loops with cooperative motions to the extensive communication network of the complex.     

Chitosan film containing fucoidan as a wound dressing for dermal burn healing: Preparation and in vitro/in vivo evaluation

The aim of this study was to develop chitosan film containing fucoidan and to investigate its suitability for the treatment of dermal burns on rabbits. Porous films, thickness between 29.7 and 269.0 μm, were obtained by the solvent dropping method. Water vapor permeability (3.3–16.6/0.1 g), the swelling (0.67–1.77 g/g), tensile strength (7.1–45.8 N), and bioadhesion (0.076–1.771 mJ/cm²) of the films were determined. The thinnest films were obtained with the lowest chitosan concentration (P<.05). The water absorption capacity of the films sharply increased with the freeze-drying technique. The film having the thickness of 29.7 μm showed the highest amount of moisture permeability (16.6 g/0.1 g). Higher chitosan concentration significantly increased tensile strength of the films (P<.05). Using higher concentration of lactic acid made films more elastic and applicable, and these films were selected for in vivo studies. Seven adult male New Zealand white rabbits were used for the evaluation of the films on superficial dermal burns. Biopsy samples were taken at 7, 14, and 21 days after wounding, and each wound site was examined macroscopically and histopathologically. After 7 days treatment, fibroplasia and scar were observed on wounds treated with fucoidan-chitosan film. The best regenerated dermal papillary formation, best reepithelization, and the fastest closure of wounds were found in the fucoidan-chitosan film treatment group after 14 days compared with other treatment and control groups. It can be concluded that fucoidan-chitosan films might be a potential treatment system for dermal burns and that changing formulation variables can modulate the characterizations of the films. Published: May 24, 2007