Electrooxidation of the iodides [C(4)mim]I, LiI, NaI, KI, RbI, and CsI in the room temperature ionic liquid [C(4)mim][NTf2]

The electrochemical oxidation of 1-butyl-3-methylimidazolium iodide, [C(4)mim]I, has been investigated by cyclic voltammetry at a platinum microelectrode at varying concentrations in the RTIL 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [C(4)mim][NTf2]. Two oxidation peaks were observed. The first peak is assigned to the oxidation of iodide to triiodide, in an overall two-electron process: 3I(-)- 2e(-) -> I-3(-). At higher potentials, the electrogenerated triiodide oxidizes to iodine, in an overall one-electron process: I-3(-) - e(-) -> 3/2I(2). An average diffusion coefficient, D, for I- of 1.55 x 10(-11) m(2) s(-1) was obtained. A digital simulation program was used to simulate the voltammetric response, and kinetic parameters were successfully extracted. The parameters deduced from the simulation include D for I-, I-3(-), and I-2 and K-eq,K-2, the equilibrium constant for the reaction of iodide and iodine to form triiodide. Values for these parameters are of the same order as those previously published for the oxidation of Br- in the same RTIL [Allen et al. J. Electroanal. Chem. 2005, 575, 311]. Next, the cyclic voltammetry of five different inorganic iodide salts was studied by dissolving small amounts of the solid in [C(4)mim][NTf2]. Similar oxidation peaks were observed, revealing diffusion coefficients of ca. 0.55, 1.14, 1.23, 1.44, and 1.33 x 10(-11) m(2) s(-1) and solubilities of 714, 246, 54, 83, and 36 mM for LiI, NaI, KI, RbI, and CsI, respectively. The slightly smaller diffusion coefficients for the XI salts (compared to [C(4)mim]I) may indicate that I- is ion-paired with Li+, Na+, K+, Rb+, and Cs+ in the RTIL medium.

A genome-wide linkage scan for genes controlling variation in urinary albumin excretion in type ll diabetes

The main hallmark of diabetic nephropathy is elevation in urinary albumin excretion. We performed a genome-wide linkage scan in 63 extended families with multiple members with type II diabetes. Urinary albumin excretion, measured as the albumin-to-creatinine ratio (ACR), was determined in 426 diabetic and 431 nondiabetic relatives who were genotyped for 383 markers. The data were analyzed using variance components linkage analysis. Heritability (h2) of ACR was significant in diabetic (h2=0.23, P=0.0007), and nondiabetic (h2=0.39, P=0.0001) relatives. There was no significant difference in genetic variance of ACR between diabetic and nondiabetic relatives (P=0.16), and the genetic correlation (rG=0.64) for ACR between these two groups was not different from 1 (P=0.12). These results suggested that similar genes contribute to variation in ACR in diabetic and nondiabetic relatives. This hypothesis was supported further by the linkage results.

Glucose-induced oxidative stress in mesangial cells.

Background: Hyperglycaemia is a well recognized pathogenic factor of long term complications in diabetes mellitus. Hyperglycaemia not only generates reactive oxygen species but also attenuates antioxidant mechanisms creating a state of oxidative stress. Methods: Porcine mesangial cells were cultured in high glucose (HG) for ten days to investigate the effects on the antioxidant defences of the cell. Results: Mesangial cells cultured in HG conditions had significantly reduced levels of glutathione (GSH) compared with those grown in normal glucose (NG). The reduced GSH levels were accompanied by decreased gene expression of both subunits of gamma-glutamylcysteine synthetase (gamma-GCS), the rate-limiting enzyme in de novo synthesis of GSH. Elevated levels of intracellular malondialdehyde (MDA) were found in cells exposed to HG conditions. HG also caused elevated mRNA levels of the antioxidant enzymes CuZn superoxide dismutase (SOD) and MnSOD. These changes were accompanied by increased mRNA levels of extracellular matrix proteins (ECM), fibronectin (FN) and collagen IV (CIV). Addition of antioxidants to high glucose caused a significant reversal of FN and CIV gene expression; alpha-lipoic acid also upregulated gamma-GCS gene expression and restored intracellular GSH and MDA levels. Conclusions: We have demonstrated the existence of glucose induced-oxidative stress in mesangial cells as evidenced by elevated MDA and decreased GSH levels. The decreased levels of GSH are as a result of decreased mRNA expression of gamma-GCS within the cell. Antioxidants caused a significant reversal of FN and CIV gene expression suggesting an aetiological link between oxidative stress and increased ECM protein synthesis.

Nonapical and Cytoplasmic Expression of Interleukin-8, CXCR1, and CXCR2 Correlates with Cell Proliferation and Microvessel Density in Prostate Cancer

Purpose: We characterized interleukin-8 (IL-8) and IL-8 receptor expression (CXCR1 and CXCR2) in prostate cancer to address their significance to this disease. Experimental Design: Immunohistochemistry was conducted on 40 cases of human prostate biopsy containing histologically normal and neoplastic tissue, excised from patients with locally confined or invasive androgen-dependent prostate cancer, and 10 cases of transurethral resection of the prostate material from patients with androgen-independent disease. Results: Weak to moderate IL-8 expression was strictly localized to the apical membrane of normal prostate epithelium. In contrast, membranous expression of IL-8, CXCR1, and CXCR2 was nonapical in cancer cells of Gleason pattern 3 and 4, whereas circumferential expression was present in Gleason pattern 5 and androgen-independent prostate cancer. Each of IL-8, CXCR1, and CXCR2 were also increasingly localized to the cytoplasm of cancer cells in correlation with advancing stage of disease. Cytoplasmic expression (but not apical membrane expression) of IL-8 in Gleason pattern 3 and 4 cancer correlated with Ki-67 expression (R = 0.79; P <0.001), cyclin D1 expression (R = 0.79; P <0.001), and microvessel density (R = 0.81; P <0.001). In vitro studies on androgen-independent PC3 cells confirmed the mitogenic activity of IL-8, increasing the rate of cell proliferation through activation of both CXCR1 and CXCR2 receptors. Conclusions: We propose that the concurrent increase in IL-8 and IL-8 receptor expression in human prostate cancer induces autocrine signaling that may be functionally significant in initiating and promoting the progression of prostate cancer by underpinning cell proliferation and angiogenesis.

Reduced K-theory for Azumaya algebras

Abstract In the theory of central simple algebras, often we are dealing with abelian groups which arise from the kernel or co-kernel of functors which respect transfer maps (for example K-functors). Since a central simple algebra splits and the functors above are “trivial” in the split case, one can prove certain calculus on these functors. The common examples are kernel or co-kernel of the maps Ki(F)?Ki(D), where Ki are Quillen K-groups, D is a division algebra and F its center, or the homotopy fiber arising from the long exact sequence of above map, or the reduced Whitehead group SK1. In this note we introduce an abstract functor over the category of Azumaya algebras which covers all the functors mentioned above and prove the usual calculus for it. This, for example, immediately shows that K-theory of an Azumaya algebra over a local ring is “almost” the same as K-theory of the base ring. The main result is to prove that reduced K-theory of an Azumaya algebra over a Henselian ring coincides with reduced K-theory of its residue central simple algebra. The note ends with some calculation trying to determine the homotopy fibers mentioned above.

Optical spectroscopy of the M 15 intermediate velocity cloud

We present echelle spectrograph observations in the Na D lines, at resolutions of 6.2-8.5 km s(-1), for 11 stars located in the line-of-sight to the M15 intermediate velocity cloud (IVC), which has a radial velocity of similar to +70 km s(-1) in the Local Standard of Rest. This cloud is a part of IVC Complex gp. The targets range in magnitude from m(V) = 13.3-14.8. Seven of the observed stars are in the M15 globular cluster, the remaining four being field stars. Three of the observed cluster stars are located near a peak in intensity of the IVC Hi column density as observed at a resolution of similar to 1 arcmin. Intermediate velocity gas is detected in absorption towards 7 stars, with equivalent widths in NaD2 ranging from similar to0.09-0.20 Angstrom, corresponding to log(10)(N-Na cm(-2)) similar to 11.8-12.5, and Na I/H I column density ratios (neglecting the HII component) ranging from similar to(1-3) x 10(-8). Over scales ranging from 30 arcsec to 1 arcmin, the Na i column density and the Na i/H i ratio varies by upto 70 per cent and a factor of similar to 2, respectively. Combining the current sightlines with previously obtained Nai data from Kennedy et al. (1998b), the Na i/H i column density ratio over cluster sightlines varies by upto a factor of similar to 25, when using Hi data of resolution similar to 2 x 1 arcmin. One cluster star, M15 ZNG-1, was also observed in the Ca i (lambda(air) = 4226.728 Angstrom) and Ca ii (lambda(air) = 3933.663 Angstrom) lines. A column density ratio N(Ca i)/N(Ca ii) <0.03 was found, typical of values seen in the warm ionised interstellar medium. Towards this sightline, the IVC has a Nai/Ca ii column density ratio of &SIM; 0.25, similar to that observed in the local interstellar medium. Finally, we detect tentative evidence for IV absorption in Ki (?(air) = 7698:974 &ANGS) towards 3 cluster stars, which have N(K i)/N(H i) ratios of &SIM;0.5-3 x 10(-9).

Structure and kinetics of phosphonopyruvate hydrolase from Variovorax sp. Pal2: New insight into the divergence of catalysis within the PEP mutase/isocitrate lyase superfamily .

Phosphonopyruvate (P-pyr) hydrolase (PPH), a member of the phosphoenolpyruvate (PEP) mutase/isocitrate lyase (PEPM/ICL) superfamily, hydrolyzes P-pyr and shares the highest sequence identity and functional similarity with PEPM. Recombinant PPH from Variovorax sp. Pal2 was expressed in Escherichia coli and purified to homogeneity. Analytical gel filtration indicated that the protein exists in solution predominantly as a tetramer. The PPH pH rate profile indicates maximal activity over a broad pH range.The steady-state kinetic constants determined for a rapid equilibrium ordered kinetic mechanism with Mg+2 binding first (Kd =140 ± 40 M), are kcat = 105 ± 2 s-1 and P-pyr Km = 5 ± 1 M. PEP (slow substrate kcat = 2 × 10-4 s-1), oxalate, and sulfopyruvate are competitive inhibitors with Ki values of 2.0 ± 0.1 mM, 17 ± 1 M, and 210 ± 10 M, respectively. Three PPH crystal structures have been determined, that of a ligand-free enzyme, the enzyme bound to Mg2+ and oxalate (inhibitor), and the enzyme bound to Mg2+ and P-pyr (substrate). The complex with the inhibitor was obtained by cocrystallization, whereas that with the substrate was obtained by briefly soaking crystals of the ligand-free enzyme with P-pyr prior to flash cooling. The PPH structure resembles that of the other members of the PEPM/ICL superfamily and is most similar to the functionally related enzyme, PEPM. Each monomer of the dimer of dimers exhibits an (/)8 barrel fold with the eighth helix swapped between two molecules of the dimer. Both P-pyr and oxalate are anchored to the active site by Mg2+. The loop capping the active site is disordered in all three structures, in contrast to PEPM, where the equivalent loop adopts an open or disordered conformation in the unbound state but sequesters the inhibitor from solvent in the bound state. Crystal packing may have favored the open conformation of PPH even when the enzyme was cocrystallized with the oxalate inhibitor. Structure alignment of PPH with other superfamily members revealed two pairs of invariant or conservatively replaced residues that anchor the flexible gating loop. The proposed PPH catalytic mechanism is analogous to that of PEPM but includes activation of a water nucleophile with the loop Thr118 residue.

A new lead for nonpeptidic active-site-directed inhibitors of the severe acute respiratory syndrome coronavirus main protease discovered by a combination of screening and docking methods.

The coronavirus main protease, Mpro, is considered to be a major target for drugs suitable for combating coronavirus infections including severe acute respiratory syndrome (SARS). An HPLC-based screening of electrophilic compounds that was performed to identify potential Mpro inhibitors revealed etacrynic acid tert-butylamide (6a) as an effective nonpeptidic inhibitor. Docking studies suggested a binding mode in which the phenyl ring acts as a spacer bridging the inhibitor's activated double bond and its hydrophobic tert-butyl moiety. The latter is supposed to fit into the S4 pocket of the target protease. Furthermore, these studies revealed etacrynic acid amide (6b) as a promising lead for nonpeptidic active-site-directed Mpro inhibitors. In a fluorimetric enzyme assay using a novel fluorescence resonance energy transfer (FRET) pair labeled substrate, compound 6b showed a Ki value of 35.3 M. Since the novel lead compound does not target the S1', S1, and S2 subsites of the enzyme's substrate-binding pockets, there is room for improvement that underlines the lead character of compound 6b.

Clinical and immunohistochemical assessment of vulval intraepithelial neoplasia following photodynamic therapy using a novel bioadhesive patch-type system loaded with 5-aminolevulinic acid

Background: The work in this study appraised photodynamic treatment (PDT) as a treatment method for vulval intraepithelial neoplasia (VIN) using a novel bioadhesive patch to deliver aminolevulinic acid. An analysis of changes in expression of apoptotic and cell cycle proteins (p53, p21, Mdm2, Blc-2, Bax, Ki-67) in response to PDT was evaluated. Methods: PDT was performed using non-laser light, either as a one or two-cycle treatment, with clinical and pathological assessment following after 6 weeks. Twenty-three patients with 25 VIN lesions underwent 49 cycles of PDT Patches were designed to conform to uneven vulval skin and contained 38 mg cm(-2) aminolevulinic acid. Assessment was carried out at 6 weeks post-treatment. Patient-based treatment assessment, along with clinical and pathological changes, were monitored. Immunohistochemical staining was used to elucidate a possible biomolecular basis for induced cellular changes. Results: Most patients (52%) reported a symptomatic response, with normal pathology restored in 38% of lesions. The patch was easy to apply and remove, causing minimal discomfort. Fluorescence inspection confirmed protoporphyrin accumulation. Pain during implementation of PDT was problematic, necessitating some form of local analgesia. Changes in expression of cell cycle and apoptotic-related proteins suggested involvement of apoptotic pathways. Down regulation of p21 and inverse changes in Bcl-2 and Bax were key findings. Conclusion: Treatment of VIN lesions using a novel bioadhesive patch induced changes in cell cycle and apoptotic proteins in response to PDT with possible utilisation of apoptotic pathways. The efficacy of PDT in treating VIN could be improved by a better understanding of these apoptotic mechanisms, the influence of factors, such as HPV status, and of the need for effective pain management.