A new multienzyme-type biosensor for triglyceride determination

An amperometric multienzyme biosensor for determination of triglycerides (TGs) was constructed by mounting three gelatin membrane-bound enzymes on a glassy carbon electrode (working electrode), then connecting it to electrometer along with an Ag/AgCl reference electrode and a Pt auxiliary electrode. Characterization and optimization of the multienzyme biosensor, which is prepared with glycerol kinase (GK) (E.C.2.7.1.30), glycerol-3-phosphate oxidase (GPO) (EC 1.1.3.21), and lipase (EC 3.1.1.3), were studied. In the optimization studies for the bioactive layer components of the prepared biosensor, the optimum amounts of gelatin, bovine serum albumin (BSA), and glutaraldehyde was calculated as 1 mg/cm², 1 mg/cm², and 2.5%, respectively. Optimum pH and temperature of the reaction of biosensor were determined as 7.0 and 40°C, respectively. Linear range of triolein for the biosensor was found from the calibration curve between several substrate concentration and Δ Current. After optimization and characterization of the biosensor, its operationability in triglycerides was also tested.     

Kinetic and docking studies of phenol-based inhibitors of carbonic anhydrase isoforms I, II, IX and XII evidence a new binding mode within the enzyme active site

Carbonic anhydrases (CAs, EC 4.2.1.1) are inhibited by sulfonamides, inorganic anions, phenols, coumarins (acting as prodrugs) and polyamines. A novel class of CA inhibitors (CAIs), interacting with the CA isozymes I, II (cytosolic) and IX, XII (transmembrane, tumor-associated) in a different manner, is reported here. Kinetic measurements allowed us to identify hydroxy-/methoxy-substituted benzoic acids as well as di-/tri-methoxy benzenes as submicromolar-low micromolar inhibitors of the four CA isozymes. Molecular docking studies of a set of such inhibitors within CA I and II allowed us to understand the inhibition mechanism. This new class of inhibitors binds differently compared to all other classes of inhibitors known to date: they were found between the phenol-binding site and the coumarin-binding site, filling thus the middle of the enzyme cavity. They exploit different interactions with amino acid residues and water molecules from the CA active site compared to other classes of inhibitors, offering the possibility to design CAIs with an interesting inhibition profile compared to the clinically used sulfonamides/sulfamates.     

Ki-67 immunostaining and stereologic estimation of nuclear volume in melanocytic skin tumors

OBJECTIVE: To investigate the proliferative activity and mean nuclear volume (MNV) of melanocytic skin tumors. STUDY DESIGN: Proliferative activity, assessed by immunostaining for the Ki-67 monoclonal antibody (reactive with all actively cycling cells), and MNV, estimated by means of a stereologic method, were determined in 60 cutaneous melanocytic tumors, including 28 primary malignant melanomas (PMM), 13 compound nevi (CN), 11 dysplastic nevi and 8 metastatic malignant melanomas. RESULTS: Both MNV and Ki-67 expression differed significantly between CN and other melanocytic tumors and showed a good correlation with Clark's level (a well-established prognostic parameter in PMM). CONCLUSION: The association of proliferative activity and quantitative nuclear features may be helpful in the interpretation of the degree of malignancy in melanocytic skin tumors.     

Reversible immobilization of uricase on conductive polyaniline brushes grafted on polyacrylonitrile film

Polyacrylonitrile film (PAN) surfaces were modified with chemical polymerization of conductive polyaniline (PANI) in the presence of potassium dichromate as an oxidizing agent. The conductive films were used for immobilization of uricase. The surface resistance of the conductive film in this work was found to be 0.97 kΩ/cm. The maximum amount of immobilized enzyme on conductive film containing 2.4% PANI was about 216 μg/cm². The optimum pH for free and immobilized enzymes was observed at 7.0 and 7.5, respectively. The K _m values for free and immobilized uricase were found to be 94 and 138 μM, respectively. V _max values were calculated as 1.87 and 1.63 U/mg protein for the free and immobilized enzymes, respectively. Immobilized uricase exhibited ~68% of its original activity even after 2 months of storage at 4 °C while the free enzyme lost its initial activity within 4 weeks.     

Genotoxic action of fungicide Conan 5FL (hexaconazole) on mammalian cells in vivo and in vitro

The genotoxic effects of fungicide Conan 5FL (containing 50 g/L hexaconazole) in mouse bone-marrow cells and human lymphocytes have been evaluated. Three different concentrations of Conan 5FL (17.50, 35.00 and 70.00 microg/mL for human lymphocytes and 17.50, 35.00 and 70.00 mg/kg for mouse bone marrow cells) were studied. Conan 5FL induced significant increases (except 17.50 mg/kg for mouse bone marrow) in the frequency of chromosomal aberrations (CAs) in both test systems. This fungicide caused structural and numerical abnormalities in both mammalian cells. These are sister chromatid union, chromatid and chromosome breaks, fragments, dicentric and ring chromosomes, and polyploidy. Significant increase was found in induction and in minimum-maximum numbers of sister chromatid exchanges (SCEs) at all treatments compared with the negative control. Conan 5FL did not affect the replication index (RI) in human lymphocyte cultures, however, it significantly decreased the mitotic index (MI) in all treatment concentrations in both test systems. Using of Conan 5FL should be reconsidered due to its possible cytotoxic, clastogenic and mutagenic effects.     

Karyotype analysis of some Minuartia L. (Caryophyllaceae) taxa

Karyotypic characters, mitotic metaphase chromosomes, monoploid idiograms and karyograms of Minuartia anatolica (Boiss.) Woronow var. phrygia (Bornm.) McNeill, Minuartia anatolica (Boiss.) Woronow var. scleranthoides (Boiss. & Noe) McNeill, Minuartia corymbulosa (Boiss. & Balansa) McNeill var. gypsophilloides McNeill and Minuartia aksoyi M.Koç & Hamzao?lu were investigated for the first time. Analysis of somatic metaphases showed that the chromosome numbers and the formulas of these taxa were 2n = 24 = 14m + 6sm + 4st for Minuartia anatolica var. phrygia, 2n = 14 = 6m + 8sm for Minuartia anatolica var. scleranthoides, 2n = 14 = 6m + 4sm + 4st for Minuartia corymbulosa var. gypsophilloides and 2n = 30 = 14m + 10sm + 6st for Minuartia aksoyi. No satellites were observed in the karyotypes of these taxa. Karyotype asymmetry was estimated by many different methods, namely the Stebbins classification, the karyotype asymmetry index (As K %), the total form percent (TF %), the Rec and Syi indices, the intrachromosomal asymmetry index (A1) and interchromosomal asymmetry index (A2), the dispersion index (DI), the degree of asymmetry of karyotype (A index) and the asymmetry index (AI).     

Goldston syndrome: report of a case.

Cerebrohepatorenal malformation is a rare familial disorder characterized by typical renal lesions combined with Dandy-Walker malformation, and congenital hepatic fibrosis. In this case report, a male premie with the diagnosis of cerebrorenal syndrome or so called Goldston syndrome is presented. Besides the rarity of this syndrome, this case is the second reported patient diagnosed prenatally.