Electrochemical study of the complexes of aspartame with Cu(II), Ni(II) and Zn(II) ions in the aqueous medium

The voltammetric behaviours of aspartame in the presence of some metal ions (Cu(II), Ni(II), Zn(II)) were investigated. In the presence of aspartame, copper ions reduced at two stages with quasi-reversible one-electron and, with increasing the aspartame (L) concentration, Cu(II)L(2) complex reduces at one-stage with irreversible two-electron reaction (-0.322 V). Zn(II)-aspartame complex (logbeta=3.70) was recognized by a cathodic peak at -1.320 V. Ni(II)-aspartame complex (logbeta=6.52) is reduced at the more positive potential (-0.87 V) than that of the hydrated Ni(II) ions (-1.088 V). In the case of the reduction of Ni(II) ions, aspartame serves as a catalyst. From electronic spectra data of the complexes, their stoichiometries of 1:2 (metal-ligand) in aqueous medium are determined. The greatness of these logarithmic values is agreement with Irwing-Williams series (NiZn).     

A novel and short synthesis of (1,4/2)-cyclohex-5-ene-triol and its conversion to (+/-)-proto-quercitol

(1,4/2)-cyclohex-5-ene-triol was synthesized starting from cyclohexa-1,4-diene with two different approaches. Photooxygenation of cyclohexa-1,4-diene and epoxy-cyclohexene afforded anti-2,3-dioxabicyclo[2.2.2]oct-7-en-5-yl hydroperoxide and anti-7-oxabicyclo[4.1.0]hept-4-en-3-yl hydroperoxide, respectively. Hydroperoxy endoperoxide was reduced with aqueous sodium bisulfite; hydroperoxy-epoxide with dimethylsulfide-titanium tetraisopropoxide to give 7-oxabicyclo[4.1.0]hept-4-en-3-ol. Acidic hydrolysis of the epoxy-alcohol gave the (1,4/2)-cyclohex-3-ene-triol. Oxidation of the double bond with KMnO4 resulted in the formation of (+/-)-proto-quercitol.     

Affinity membrane chromatography: relationship of dye-ligand type to surface polarity and their effect on lysozyme separation and purification

Two different dye-ligands, i.e. Procion Brown MX-5BR (RB-10) and Procion Green H-4G (RG-5) were immobilised onto poly(2-hydroxyethylmethacrylate) (pHEMA) membranes. The polarities of the affinity membranes were determined by contact angle measurements. Separation and purification of lysozyme from solution and egg white were investigated. The adsorption data was analysed using two adsorption kinetic models the first order and the second order to determine the best-fit equation for the separation of lysozyme using affinity membranes. The second-order equation for the adsorption of lysozyme on the RB-10 and RG-5 immobilised membranes systems is the most appropriate equation to predict the adsorption capacity for the affinity membranes. The reversible lysozyme adsorption on the RB-10 and RG-5 did not follow the Langmuir model, but obeyed the Temkin and Freundlich isotherm model. Separation and purification were monitored by determining the lysozyme activity using Micrococcus lysodeikticus as substrate. The purities of the eluted lysozyme, as determined by HPLC, were 76 and 92% with recovery 63 and 77% for RB-10 and RG-5 membranes, respectively. For the separation and purification of lysozyme the RG-5 immobilised membrane provided the best results. The affinity membranes are stable when subjected to sanitization with sodium hydroxide after repeated adsorption-elution cycles.     

Agomelatine modulates calcium signaling through protein kinase C and phospholipase C-mediated mechanisms in rat sensory neurons

Agomelatine, a novel antidepressant exerting its effects through melatonergic and serotonergic systems, implicated to be effective against pain including neuropathic pain but without any knowledge of mechanism of action. To explore the possible role of agomelatine on nociceptive transmission at the peripheral level, the effects of agomelatine on intracellular calcium ([Ca²⁺]_i) signaling in peripheral neurons were investigated in cultured rat dorsal root ganglion (DRG) neurons. Using the fura-2-based calcium imaging technique, the effects of agomelatine on [Ca²⁺]_i and roles of the second messenger-mediated pathways were assessed. Agomelatine caused [Ca²⁺]_i signaling in a dose-dependent manner when tested at 10 and 100 μM concentration. Luzindole, a selective melatonin receptor antagonist, almost completely blocked the agomelatine-induced calcium signals. The agomelatine-induced calcium transients were also nearly abolished following pretreatment with the 100 ng/ml pertussis toxin, a Gi/o protein inhibitor. The stimulatory effects of agomelatine on [Ca²⁺]_i transients were significantly reduced by applications of phospholipase C (PLC) and protein kinase C (PKC) blockers, 10 μM U73122, and 10 μM chelerythrine chloride, respectively. The obtained results of agomelatine-induced [Ca²⁺]_i signals indicates that peripheral mechanisms are involved in analgesic effects of agomelatine. These mechanisms seems to involve G-protein-coupled receptor activation and PLC and PKC mediated mechanisms.     

Interspecific variability of RAPD and fatty acid composition of some pomegranate cultivars (Punica granatum L.) growing in Southern Anatolia Region in Turkey

The interspecific variability of fatty acid (FA) composition and RAPD profiles was used to examine biochemical and genetic relationships among six pomegranate cultivars, which dominate pomegranate production in Southern Anatolia Region of Turkey. Fatty acid composition of pomegranate leaves was determined by using gas chromatography. Differences in the FA composition were found among cultivars. In particular, cv. kirli hanim had a distinct fatty acid profile that differs from the other cultivars. Linoleic acid was not detected in this cultivar, whereas the other cultivars had various levels of linoleic acid. RAPD data also showed that this cultivar formed a unique pattern. The differences in the composition of fatty acids among pomegranate cultivars suggested that fatty acid profiles could be used to differentiate among some of the pomegranate cultivars. RAPD analysis was also useful for grouping the pomegranate cultivars.     

Chemical compositions,antimicrobial and herbicidal effects of essential oils isolated from Turkish Tanacetum aucheranum and Tanacetum chiliophyllum var. chiliophyllum

The chemical composition of essential oils isolated from the aerial parts by hydrodistillation of Turkish Tanacetum aucheranum and Tanacetum chiliophyllum var. chiliophyllum were analyzed by GC–MS. The oils contain similar major components. The major components of T. aucheranum oil were 1,8-cineole (23.8%), camphor (11.6%), terpinen-4-ol (7.2%), α-terpineol (6.5%), borneol (3.8%), (E)-thujone (3.2%), epi-α-cadinol (3.1%), and artemisia ketone (3.0%). Camphor (17.9%), 1,8-cineole (16.6%) and borneol (15.4%) were found to be predominant constituents in the oil of T. chiliophyllum. It is interesting to find that ester derivatives of dihydro-α-cyclogeranic acid (2,2,6-trimethylcyclohexylcarboxylate), dihydro-α-cyclogeranyl hexanoate (10.1%), dihydro-α-cyclogeranyl pentanoate (3.0%), dihydro-α-cyclogeranyl butanoate (2.1%) and dihydro-α-cyclogeranyl propionate (1.2%) are firstly found as chemotaxonomically important components in T. chiliophyllum oil. From these, dihydro-α-cyclogeranyl hexanoate was isolated on silica gel column chromatography and its structure was confirmed by spectroscopic methods. This is the first report on the occurrence of ester derivatives of dihydro-α-cyclogeranic acid in essential oils of Tanacetum species. The oils were also characterized to have relatively high amounts of oxygenated monoterpenes. Results of the antifungal testing by microbial growth inhibition assays showed that the oils completely inhibit the growth of 30 phytopathogenic fungi. However, their growth inhibition effects were lower than commercial benomyl. The oils tested for antibacterial activity against 33 bacterial strains showed a considerable antibacterial activity over a wide spectrum. Herbicidal effects of the oils on seed germination of Amaranthus retroflexus, Chenopodium album and Rumex crispus were also determined and the oils completely inhibited the seed germination and seedling growth of the plants.     

Inhibition of carbonic anhydrase isoforms I,II, IX and XII with secondary sulfonamides incorporating benzothiazole scaffolds

Carbonic anhydrases (CAs, EC 4.2.1.1) catalyze the fundamental reaction of CO₂ hydration in all living organisms, being actively involved in the regulation of a plethora of patho/physiological conditions. A series of benzothiazole-based sulfonamides were synthesized and tested as possible CA inhibitors. Their inhibitory activity was assessed against the cytosolic human isoforms hCA I and hCA II and the transmembrane hCA IX and hCA XII. Several of the investigated derivatives showed interesting inhibition activity and selectivities for inhibiting hCA IX and hCA XII over the off-target ones hCA I and hCA II. Furthermore, computational procedures were used to investigate the binding mode of this class of compounds, within the active site of hCA IX.     

Impact of Laboratory Test Use Strategies in a Turkish Hospital

ObjectivesEliminating unnecessary laboratory tests is a good way to reduce costs while maintain patient safety. The aim of this study was to define and process strategies to rationalize laboratory use in Ankara Numune Training and Research Hospital (ANH) and calculate potential savings in costs.MethodsA collaborative plan was defined by hospital managers; joint meetings with ANHTA and laboratory professors were set; the joint committee invited relevant staff for input, and a laboratory efficiency committee was created. Literature was reviewed systematically to identify strategies used to improve laboratory efficiency. Strategies that would be applicable in local settings were identified for implementation, processed, and the impact on clinical use and costs assessed for 12 months.ResultsLaboratory use in ANH differed enormously among clinics. Major use was identified in internal medicine. The mean number of tests per patient was 15.8. Unnecessary testing for chloride, folic acid, free prostate specific antigen, hepatitis and HIV testing were observed. Test panel use was pinpointed as the main cause of overuse of the laboratory and the Hospital Information System test ordering page was reorganized. A significant decrease (between 12.6–85.0%) was observed for the tests that were taken to an alternative page on the computer screen. The one year study saving was equivalent to 371,183 US dollars.ConclusionHospital-based committees including laboratory professionals and clinicians can define hospital based problems and led to a standardized approach to test use that can help clinicians reduce laboratory costs through appropriate use of laboratory tests.     

Cytotoxic and apoptotic effects of menadione on rat hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is one of the most common cancers, which may lead to death. Menadione shows cytotoxic activity thought affecting redox cycling in cancer cells. The aim of the present study was to investigate the effects of menadione on rat hepatocellular carcinoma (H4IIE) cell morphology, cytotoxicity, apoptosis and DNA damage or repair in vitro. Cell morphology evaluated by microscopy and cell viability was determined using the 3-[4,5-dimethylthiazol-2yl]-diphenyltetrazolium bromide test. Apoptotic cell death was assessed in H4IIE cells treated with menadione by 4′,6-diamidino-2-phenylindole staining. Quantitative real time polymerase chain reaction used to determine the expression level of poly (ADP-ribose) polymerase 1 (PARP1) gene. According to the results of this study menadione has got a cytotoxic activity (IC₅₀ 25 µM) and change the cell fate in H4IIE cells. Menadione treatments lead to PARP1 activation in a dose dependent manner and induce DNA damage and apoptosis, and this may suggest its use as a therapeutic agent in HCC treatment.