A novel bioassay for human somatogenic activity in serum samples supports the clinical reliability of immunoassays

OBJECTIVE Because there is discordance between different immunoassay values for serum hGH, and because clinical state may not correlate with immunoreactive hGH, we have developed an assay to accurately measure serum hGH somatogenic bioactivity. The results of this assay were compared with the Elegance two-site ELISA assay across 135 patient samples in a variety of clinical states. DESIGN The somatogenic assay was based on stable expression of hGH receptor in the murine BaF line, allowing these cells to proliferate in response to hGH. To eliminate interference by other growth factors in serum, we created a specific antagonist of the hGH receptor (similar to Trovert or Pegvisomant) which allowed us to obtain a true measure of hGH somatogenic activity by subtraction of the activity in the presence of the antagonist. The assay was carried out in microtiter plates over 24 h, with oxidation of a chromogenic tetrazolium salt (MTT) as the endpoint. PATIENTS These encompassed a number of different clinical conditions related to short stature, including idiopathic short stature, neurosecretory dysfunction and renal failure, as well as obese patients on dietary restriction and normal volunteers. MEASUREMENTS In addition to the colourimetric (MTT) response to hGH, we measured free hGH by stripping out GHBP-bound hGH using beads coupled to a monoclonal antibody to the GHBP (GH binding protein). All samples were measured in both bioassay and ELISA assay. RESULTS This bioassay was sensitive (5 mU/l or 2 mug/l) and precise, and not subject to interference by the GHBP. There was a good correlation (r = 0.95) between bioactivity and immunoactivity across clinical states. There was, however, an increased bioactivity during secretory peaks (over 25 mU/l), which has been reported previously for the Nb2 bioassay. Free hGH did not correlate with clinical state. CONCLUSIONS Because the results of the Elegance ELISA and the bioassay correlate well, even though there is greater bioactivity at higher hormone concentrations, it is evident that an appropriate immunoassay is able to act as a reliable indicator for clinical assessment. In those rare cases where bio-inactive GH exists, our bioassay should provide an appropriate means to demonstrate this.

Bovine-serum-albumin-containing receptor phase better predicts transdermal absorption parameters for lipophilic compounds

Based on the hypothesis that limited receptor solubility of lipophilic compounds may result in lower observed permeability parameters, the aim of this study was to determine the in vitro human epidermal permeability coefficients and membrane retention of a series of aliphatic alcohols (C1-C10, log p -0.72 to 4.06) using two different receptor solutions (water and 4% bovine serum albumin in phosphate-buffered saline). Aqueous solutions of radiolabeled alcohols were dosed into the stratum corneum side of membranes mounted in side-by-side glass diffusion cells. Appearance of alcohol in the receptor compartment filled with either of the two solutions was monitored over a 7 h period when both stratum corneum (assessed by tape stripping) and the remaining epidermis levels of radioactivity were determined. In a separate study the degree of binding of alcohols to 4% bovine serum albumin was determined. The data showed increased receptor phase solubility in the bovine serum albumin solution and higher permeability coefficients for the more lipophilic alcohols in the series. No changes were seen in the partitioning of the alcohols from the vehicle into either the stratum corneum or tape-stripped epidermis with the two receptor phases; however, a decrease in the amount of the more lipophilic alcohols partitioning into the water receptor phase from the tape-stripped epidermis was observed. We conclude that bovine serum albumin receptor phase allows better estimation of real permeability parameters for lipophilic compounds due to its increased solubility capacity and we question whether permeability parameters for lipophilic solutes from older data sets based on aqueous receptor phases are completely reliable.

Direct electrochemistry of a bacterial sulfite dehydrogenase

Sulfite dehydrogenase from Starkeya novella is an alphabeta heterodimer comprising a 40.6 kDa subunit (containing the Mo cofactor) and a smaller 8.8 kDa heme c subunit. The enzyme catalyses the oxidation of sulfite to sulfate with the natural electron acceptor being cytochrome c(550). Its catalytic mechanism is thought to resemble that found in eukaryotic sulfite oxiclases. Using protein film voltammetry and redox potentiometry, we have identified both Mo- and heme-centered redox responses from the enzyme immobilized on a pyrolytic graphite working electrode: E-m,E-8 (Fe-III/II) +177 mV; E-m,E-8 (Mo-VI/V) +211 mV and E(m,)8 (Mo-V/IV) -118 mV vs NHE; Upon addition of sulfite to the electrochemical cell a steady-state voltammogram is observed and an apparent Michaelis constant (K-m) of 26(l) muM was determined for the enzyme immobilized on the working electrode surface, which is comparable with the value obtained from solution assays.

Unexpected clobetasol propionate profile in human stratum corneum after topical application in vitro

Purpose. The validity of using drug amount-depth profiles in stratum corneum to predict uptake of clobetasol propionate into stratum corneum and its transport into deeper skin layers was investigated. Methods. In vitro diffusion experiments through human epidermis were carried out using Franz-type glass diffusion cells. A saturated solution of clobetasol propionate in 20% (V/V) aqueous propylene glycol was topically applied for 48 h. Steady state flux was calculated from the cumulative amount of drug permeated vs. time profile. Epidermal partitioning was conducted by applying a saturated drug solution to both sides of the epidermis and allowing time to equilibrate. The tape stripping technique was used to define drug concentration-depth profiles in stratum corneum for both the diffusion and equilibrium experiments. Results. The concentration-depth profile of clobetasol propionate in stratum corneum for the diffusion experiment is biphasic. A logarithmic decline of the drug concentration over the first four to five tape strips flattens to a relatively constant low concentration level in deeper layers. The drug concentration-depth profile for the equilibrium studies displays a similar shape. Conclusions. The shape of the concentration-depth profile of clobetasol propionate is mainly because of the variable partitioning coefficient in different stratum corneum layers.

Redox active macrocyclic receptors for neutral guests

A novel series of triazine-appended macrocyclic complexes has been investigated as potential hydrogen bonding receptors for complementarily disposed heterocycles. Cocrystallization of a melamine-appended azacyclam complex of Cull has been achieved with barbitone, the barbiturate anion and thymine. In each case, a complementary DAD/ADA hydrogen bonding motif between the melamine group and the heterocycle has been identified by X-ray crystallography. Electrochemical studies of the copper macrocycles in both nonaqueous and aqueous solution show anodic shifts of the CuII/I redox couple of more than 60 mV upon addition of guest molecules with matching H-bonding motifs. The Zn-II analogues have been synthesized via transmetalation of the Cull complex, and their guest binding properties investigated by NMR spectroscopy. H-1 NMR shifts of up to 0.8 ppm were observed upon addition of guest, and stability constants are similar to those obtained electrochemically.

Molybdenum Complexes Bearing the Tris(1-pyrazolyl)methanesulfonate Ligand: Synthesis, Characterization and Electrochemical Behaviour

The tris(1-pyrazolyl)methanesulfonate lithium salt Li(Tpms) [Tpms = SO3C(pz)(3)-] reacts with [Mo(CO)(6)] in NCMe heated at reflux to yield Li[Mo(Tpms)(CO)(3)] (1), which, upon crystallization from thf, forms the coordination polymer [Mo(Tpms)(CO)(2)(mu-CO)Li(thf)(2)](n) (2). Reaction of 1 with I-2, HBF4 or AgBF4 yields [Mo(Tpms)I(CO)(3)] (3), (Mo(Tpms)-H(CO)(3)] (5) or (Mo(Tpms)O-2](2)(mu-O) (7), respectively. The high-oxidation-state dinuclear complexes [{Mo(Tpms)O(mu-O)}(2)] (4) and [{Mo(tpms)OCl)(2)](mu-O) (6) are formed upon exposure to air of solutions of 3 and 5, respectively. Compounds 1-7, which appear to be the first tris(pyrazolyl)methanesulfonate complexes of molybdenum to be reported, were characterized by IR, H-1 and C-13 NMR spectroscopy, ESI-MS, elemental analysis, cyclic voltammetry and, in the cases of Li(Tpms) and compounds 2, 4.2CH(3)CN, 6.6CHCl(3) and 7, by X-ray diffraction analyses. Li(Tpms) forms a 1D polymeric structure (i.e., [Li(tpms)](n)} with Tpms as a tetradentate N2O2 chelating ligand that bridges two Li cations with distorted tetrahedral coordination. Compound 2 is a 1D coordination polymer in which Tpms acts as a bridging tetradentate N3O ligand and each Li(thf)(2)(+) moiety is coordinated by one bridging CO ligand and by the sulfonyl group of a contiguous monomeric unit. In 4, 6 and 7, the Tpms ligand is a tridentate chelator either in the NNO (in 4) or in the NNN (in 6 and 7) fashion. Complexes 1, 3 and 5 exhibit, by cyclic voltammetry, a single-electron oxidation at oxidation potential values that indicate that the Tpms ligand has an electron-donor character weaker than that of cyclopentadienyl.

Estudo da viabilidade de um processo de captura do dióxido de carbono emitido em gases de combustão

O presente trabalho descreve o estudo da viabilidade económica de implementar um processo de absorção química com monoetanolamina (MEA) numa central termoeléctrica, visando a captura de CO2 dos gases de exaustão da mesma, dado que na indústria, o sector de produção de energia eléctrica é o principal responsável pela emissão de CO2 para a atmosfera. A central em foco foi a TER (Central Termoeléctrica do Ribatejo) devido à quantidade de gases emitidos e ao teor em CO2 dos mesmos, além de ser a responsável por cerca de 18% da energia eléctrica em Portugal. O processo em causa ocorre em pós-combustão, dado tratar-se de uma central já existente, e engloba a absorção química com MEA, seguida de stripping, com remoção do CO2 e recirculação da MEA. Este sistema foi testado recorrendo a um modelo de simulação desenvolvido por T. Greer, na sua tese de mestrado ao tema “Modeling and simulation of post combustion CO2 capturing” com base em Matlab. De acordo com o disposto sobre o Comércio Europeu de Licenças de Emissão (CELE), para o período de 2008-2012, foi atribuído à TER um limite de emissão de 1.423.103 ton CO2/ano. Sendo esta responsável pela emissão anual de cerca de 2X106 toneladas, determinou-se um encargo de 17.277.000 € anuais por incumprimento. Os custos de implementação deste processo estimam-se, para um período de amortização de 5 anos, em 6.546.758€, e permitiria a captação de 78,7% do CO2 emitido. As taxas respeitantes ao incumprimento ficariam reduzidas a 13.597.020€; o que significa que, com a implementação desta tecnologia, se conseguirá uma economia de: 17.277.000 - 13.597.020 = 3.679.980 €/ano. Estes valores foram calculados de acordo com o valor cotado da tonelada de CO2 para 2008 de 30 euros/ton. No período de amortização considerado, 5 anos, obtém-se uma economia de 18.399.900 €, sendo possível amortizar totalmente o investimento efectuado com a unidade de captura de CO2 sendo economicamente viável a sua implementação.

Novel Scorpionate and Pyrazole Dioxovanadium Complexes, Catalysts for Carboxylation and Peroxidative Oxidation of Alkanes

The dioxovanadium(V) complexes [VO2(3,5-Me(2)Hpz)(3)][BF4] (1) (pz = pyrazolyl), [VO2{SO3C(pz)(3)}] (2), [VO2{HB(3,5-Me(2)pz)(3)}] (3) and [VO2{HC(pz)(3)}][BF4] (4), bearing pyrazole or scorpionate ligands, were obtained by reaction of triethyl vanadate [VO(OEt)(3)] with hydrotris(3,5-dimethyl-1-pyrazolyl)methane [HC(3,5-Me(2)pz)(3)] or 3,5-dimethylpyrazole (3,5-Me(2)Hpz; 1), lithium tris(1-pyrazolyl)methanesulfonate {Li[SO3C(pz)(3)], 2}, potassium hydrotris(3,5-dimethyl-1-pyrazolyl)borate {K[HB(3,5-Me(2)pz)(3)], 3} and hydrotris(1-pyrazolyl)methane [HC(pz)(3), 4], respectively. Treatment of [VO(OEt)(3)] with potassium hydrotris(1-pyrazolyl)borate {K[HB(pz)(3)]} led to the mixed eta(3)-tris(pyrazolyl)borate and eta(2)-bis(pyrazolyl)borate oxovanadium(IV) complex [VO{HB(pz)(3)}{H2B(pz)(2)}, 5]. The compounds were characterized by elemental analyses, IR, NMR and EPR spectroscopy, FAB and ESI mass spectrometry, cyclic voltammetry and, for 5, also by single crystal X-ray diffraction analysis. All complexes exhibit catalytic activity in the single-pot carboxylation [in trifluoroacetic acid/potassium peroxodisulfate (CF3COOH/K2S2O8)] of gaseous alkanes (methane and ethane) to carboxylic acids (yields up to 40%. TONs up to 157) and in the peroxidative oxidation [in water/acetonitrile (H2O/NCMe)] of liquid alkanes (cyclohexane and cyclopentane) to the corresponding alcohols and ketones (yields up to 24%, TONs up to 117), under mild conditions.

Synthesis, characterization and redox behaviour of benzoyldiazenido- and oxorhenium complexes bearing N,N- and S,S-type ligands

The reactions of [ReCl2{eta(2)-N2C(O)Ph}(PPh3)(2)](1) with 2-aminopyrimidine (H(2)Npyrm), 2,2'-bipyridine (bpy) and tetraethylthiuram disulfide (tds), in MeOH upon reflux, lead to the new eta(1)-(benzoyldiazenido)-rhenium(III) complexes [ReCl{eta(1)-N2C(O)Ph}(HNpyrm)(PPh3)(2)](2)and [ReCl2{eta(1)-N2C(O)Ph}(bpy)(PPh3)] (3), and the known oxo(diethyldithiocarbamato)dirhenium(v)complex [Re2O2(mu O){Et2NC(S)S}(4)](4), respectively. The Et2NC(S)S ligands in 4 result from S-S bond rupture of tds molecules. The obtained compounds have been characterized by IR, H-1, P-31{H-1} and C-13{H-1} NMR spectroscopies, FAB(+)-MS, elemental and single-crystal X-ray diffraction (for 2 and 4)analyses. Complex 2 represents the first structurally characterized Re compound derived from 2-aminopyrimidine. Besides, the redox behaviour of 2-4 in CH2Cl2 solution has been studied by cyclic voltammetry, and the Lever electrochemical ligand parameter (E-L)has been estimated, for the first time, for HNpyrm. The electrochemical results are discussed in terms of electronic properties of the Re centres and the ligands.

Fabrication of Three-Dimensional Dendritic Ni-Co Films By Electrodeposition on Stainless Steel Substrates

Co-deposition of nickel and cobalt was carried out on austenitic stainless steel (AISI 304) substrates by imposing a square waveform current in the cathodic region. The innovative procedure applied in this work allows creating a stable, fully developed, and open porous three-dimensional (3D) dendritic structure, which can be used as electrode for redox supercapacitors. This study investigates in detail the influence of the applied current density on the morphology, mass, and chemical composition of the deposited Ni-Co films and the resulting 3D porous network dendritic structure. The morphology and the physicochemical composition were studied by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (W). The electrochemical behavior of the materials was evaluated by cyclic voltammetry (CV). The results highlight the mechanism involved in the coelectrodeposition process and how the lower limit current density tailors the film composition and morphology, as well as its electrochemical activity.

Ruthenium(II) Arene Complexes Bearing Tris(pyrazolyl)methanesulfonate Capping Ligands.Electrochemistry, Spectroscopic, and X-ray Structural Characterization

Novel [Ru(L)(Tpms)]Cl and [Ru(L)(Tpms(Ph))]Cl complexes (L = p-cymene, benzene, or hexamethylbenzene, Tpms = tris(pyrazolyl)-methanesulfonate, Tpms(Ph) = tris(3-phenylpyrazoly)methanesulfonate) have been prepared by reaction of [Ru(L)(mu-Cl)(2)](2) with Li[Tpms] and Li[Tpms(Ph)], respectively. [Ru(p-cymene)(Tpms)]BF4 has been synthesized through a metathetic reaction of [Ru(p-cymene)(Tpms)]Cl with AgBF4. [RuCl(cod)(Tpms)] (cod = 1,5-cyclooctadiene) and [RuCl(cod)(Tpms(Ph))] are also reported, being obtained by reaction of [RuCl2(cod)(MeCN)(2)] with Li[Tpms] and Li[Tpms(Ph)], respectively. The structures of the complexes and the coordination modes of the ligands have been established by IR, NMR, and single-crystal X-ray diffraction (for [RuL(Tpms)]X (L = p-cymene or HMB, X = Cl; L = p-cymene, X = BF4)) studies. Electrochemical studies showed that each complex undergoes a single-electron R-II -> R-III oxidation at a potential measured by cyclic voltammetry, allowing to compare the electron-donor characters of the tris(pyrazolyl)methanesulfonate and arene ligands, and to estimate, for the first time, the values of the Lever E-L ligand parameter for Tmps(Ph), HMB, and cod.

Syntheses, Molecular Structures, Electrochemical Behavior, Theoretical Study, and Antitumor Activities of Organotin(IV) Complexes Containing 1-(4-Chlorophenyl)-1-cyclopentanecarboxylato Ligands

The organotin(IV) compounds [Me2Sn(L)(2)] (1), [Et(2)sn(L)(2)] (2), [(Bu2Sn)-Bu-n(L)(2)] (3), [(n)Oct(2)Sn(L)(2)] (4), [Ph2Sn(L)(2)] (5), and [PhOSnL](6) (6) have been synthesized from the reactions of 1-(4-chlorophenyl)-1-cyclopentanecarboxylic acid (HL) with the corresponding diorganotin(IV) oxide or dichloride. They were characterized by IR and multinuclear NMR spectroscopies, elemental analysis, cyclic voltammetry, and, for 2, 3, 4 and 6, single crystal X-ray diffraction analysis. While 1-5 are mononuclear diorganotin (IV) compounds, the X-ray diffraction of 6 discloses a hexameric drumlike structure with a prismatic Sn6O6 core. All these complexes undergo irreversible reductions and were screened for their in vitro antitumor activities toward HL-60, BGC-823, Bel-7402, and KB human cancer cell lines. Within the mononuclear compounds, the most active ones (3, 5) are easiest to reduce (least cathodic reduction potentials), while the least active ones (1, 4) are the most difficult to reduce. Structural rearrangements (i.e., Sn-O bond cleavages and trans-to-cis isomerization) induced by reduction, which eventually can favor the bioactivity, are disclosed by theoretical/electrochemical studies.

Synthesis, structure and electrochemical behaviour of Na, Mg-II, Mn-II, Cd-II and Ni-II complexes of 3-(2-carboxyphenylhydrazone)pentane-2,4-dione

Mononuclear manganese(II) [Mn(kappa O-HL)(2)(CH3OH)(4)] (4), nickel(II) [Ni(kappa O-2, kappa N-L)(H2O)(3)] (5), cadmium(II) [Cd(kappa O-2-HL)(2)(CH3OH)(3)] (7), tetranuclear zinc(II) [Zn-4(mu-OH)(2)(1 kappa O:2 kappa O-HL)(4)(kappa O-HL)(2)(H2O)(4)] (6) and polynuclear aqua sodium(I) [Na(H2O)(2)(mu-H2O)(2)](n)(HL)(n) (2) and magnesium(II) [Mg(OH)(H2O)(mu-H2O)(2)](n)(-HL)(n) (3) complexes were synthesized using 3-(2-carboxyphenyl-hydrazone)pentane-2,4-dione (H2L, 1) as a ligand precursor. The complexes were characterized by single crystal X-ray diffraction, elemental analysis, IR, H-1 and C-13 NMR (for 2, 3, 6 and 7) spectroscopies. Mono- or dianionic deprotonated derivatives of H2L display different coordination modes and lead to topologies and nuclearities of the complexes depending on metal ions and conditions used for the syntheses. Extensive intermolecular H-bonds form supramolecular arrangements in 1D chains (4 and 6), 1D chains of the organic anion and 2D networks of the metal-aqua aggregates (2 and 3), 2D networks (7) or even 3D frameworks (5). Electrochemical studies, by cyclic voltammetry and controlled potential electrolysis, show ligand centred redox processes as corroborated by theoretical DFT calculations in terms of LUMO and HOMO compositions. (C) 2012 Elsevier Ltd. All rights reserved.

Synthesis of new Fe(II) and Ru(II) eta(5)-monocyclopentadienyl compounds showing significant second order NLO properties

A series of new ruthenium(II) complexes of the general formula [Ru(eta(5)-C5H5)(PP)(L)][PF6] (PP = DPPE or 2PPh(3), L = 4-butoxybenzonitrile or N-(3-cyanophenyl)formamide) and the binuclear iron(II) complex [Fe(eta(5)-C5H5)(PP)(mu-L)(PP)(eta(5)-C5H5)Fe][PF6](2) (L = (E)-2-(3-(4-nitrophenyl)allylidene)malononitrile, that has been also newly synthesized) have been prepared and studied to evaluate their potential in the second harmonic generation property. All the new compounds were fully characterized by NMR, IR and UV-Vis spectroscopies and their electrochemistry behaviour was studied by cyclic voltammetry. Quadratic hyperpolarizabilities (beta) of three of the complexes have been determined by hyper-Rayleigh scattering (HRS) measurements at fundamental wavelength of 1500 nm and the calculated static beta(0) values are found to fall in the range 65-212 x 10(-30) esu. Compound presenting beta(0) = 212 x 10(-30) esu has revealed to be 1.2 times more efficient than urea standard in the second harmonic generation (SHG) property, measured in the solid state by Kurtz powder technique, using a Nd:YAG laser (1064 nm). (C) 2013 Elsevier B.V. All rights reserved.

Synthesis, characterization, electrochemical behavior and in vitro protein tyrosine kinase inhibitory activity of the cymene-halogenobenzohydroxamato [Ru(eta(6)-cymene)(bha)Cl] complexes

The ruthenium(II)-cymene complexes [Ru(eta(6)-cymene)(bha)Cl] with substituted halogenobenzohydroxamato (bha) ligands (substituents = 4-F, 4-Cl, 4-Br, 2,4-F-2, 3,4-F-2, 2,5-F-2, 2,6-F-2) have been synthesized and characterized by elemental analysis, IR, H-1 NMR, C-13 NMR, cyclic voltammetry and controlled-potential electrolysis, and density functional theory (DFT) studies. The compositions of their frontier molecular orbitals (MOs) were established by DFT calculations, and the oxidation and reduction potentials are shown to follow the orders of the estimated vertical ionization potential and electron affinity, respectively. The electrochemical E-L Lever parameter is estimated for the first time for the various bha ligands, which can thus be ordered according to their electron-donor character. All complexes exhibit very strong protein tyrosine kinase (PTK) inhibitory activity, even much higher than that of genistein, the clinically used PTK inhibitory drug. The complex containing the 2,4-difluorobenzohydroxamato ligand is the most active one, and the dependences of the PTK activity of the complexes and of their redox potentials on the ring substituents are discussed. (C) 2012 Elsevier B.V. All rights reserved.