The response properties of a new thiocyanate-selective solvent-polymeric membrane electrode are reported. The membrane contains (5,10,15,20-tetrakis( 2,4,6-triphenylphenyl)porphyrinato)manganew( Ill) chloride (Mn[TI'I'I'JCI) in a plasticized polyvinyl chloride matrix. The electrode deviates from the tiofmeister selectivity pattern by responding t o thiocyanate preferentially over inorganic anions (perchlorate, chloride, iodide, and bromide) and several organic anions often present in biological samples (ascorbate, citrate, urate, and salicylate). The performance of this electrode as an ion-selective detector in a low-dispersion, flow-injection system is also evaluated. While selectivity in such a nonequilibrium flow arrangement is found to be somewhat different than that observed under equilibrium conditions, the electrode's response and selectivity is still adequate to allow for measurement of thiocyanate in biological samples. This application is demonstrated via the flow-injection analysis (FIA) detection of thiocyanate in 22 human saliva samples with good correlation to a classical colorimetric method (r = 0.981).It is well known that solvent-polymeric membrane electrodes prepared with conventional dissociated anion exchangers (e.g., tetraalkyl ammonium or similar compounds) exhibit potentiometric anion selectivity patterns in accordance with that predicted by the Hofmeister series [ 11 (i.e,, maximum response to lipophilic anions). Recently, however, various metal-ligand complexes and organometallic species have been used to construct polymeric membrane electrodes that display markedly different anion selectivity sequences 12-12], Metalloporphyrins are one such class of membrane-active molecules that already have proven to be useful in the design of new anion-selective sensors. Previous work has established that differences in potentiometric selectivity can be achieved by changing the metal center [7, 91 and/or altering the peripheral structure of the porphyrin ring [6]. The latter approach is further demonstrated in the present study in which we describe the response ' Present address:

A potentiometric immunosensor for the detection of human IgG has been developed using an asymmetric, ion-selective membrane with immobilized adenosine deaminase and IgG. A protein A-alkaline phosphatase conjugate binds to the immobilized IgG, creating a bienzymatic catalytic layer. In the presence of sample IgG, the conjugate does not bind to the membrane. Instead, the intermediate in the two-step reaction (adenosine) must diffuse to the membrane surface, reducing the rate of product (ammonium) formation within the diffusion layer detected by the membrane. The immunosensor demonstrated is for the determination of IgG. A simplified model is described to predict the maximum rate enhancement for the 'channeled' versus 'unchanneled' reaction mechanisms.

Supplementary Figures 1-5 from <i>In Vivo</i> Activity of Combined PI3K/mTOR and MEK Inhibition in a <i>Kras^G12D</i>;<i>Pten</i> Deletion Mouse Model of Ovarian Cancer

<div>Abstract<p>The phosphatidylinositol 3-kinase (PI3K)/Akt pathway is commonly dysregulated in human cancer, making it an attractive target for novel anticancer therapeutics. We have used a mouse model of ovarian cancer generated by <i>Kras^G12D</i> activation and <i>Pten</i> deletion in the ovarian surface epithelium for the preclinical assessment of a novel PI3K/mTOR inhibitor PF-04691502. To enable higher throughput studies, we developed an orthotopic primary transplant model from these mice and evaluated therapeutic response to PF-04691502 using small-animal ultrasound and FDG-PET imaging. PF-04691502 inhibited tumor growth at 7 days by 72% ± 9. FDG-PET imaging revealed that PF-04691502 reduced glucose metabolism dramatically, suggesting FDG-PET may be exploited as an imaging biomarker of target inhibition by PF-04691502. Tissue biomarkers of PI3K/mTOR pathway activity, p-AKT (S473), and p-RPS6 (S240/244), were also dramatically inhibited following PF-04691502 treatment. However, as a single agent, PF-04691502 did not induce tumor regression and the long-term efficacy was limited, with tumor proliferation continuing in the presence of drug treatment. We hypothesized that tumor progression was because of concomitant activation of the mitogen-activated protein kinase pathway downstream of <i>Kras^G12D</i> expression promoting cell survival and that the therapeutic effect of PF-04691502 would be enhanced by combinatory inhibition of MEK using PD-0325901. This combination induced striking tumor regression, apoptosis associated with upregulation of Bim and downregulation of Mcl-1, and greatly improved duration of survival. These data suggest that contemporaneous MEK inhibition enhances the cytotoxicity associated with abrogation of PI3K/mTOR signaling, converting tumor growth inhibition to tumor regression in a mouse model of ovarian cancer driven by PTEN loss and mutant K-Ras. <i>Mol Cancer Ther; 10(8); 1440–9. ©2011 AACR</i>.</p></div>

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