HPLC micro-fractionation coupled to a cell-based assay for automated on-line primary screening of calcium antagonistic components in plant extracts

High performance liquid chromatography (HPLC) micro-fractionation was successfully coupled to an automated ⁴⁵Ca²⁺ uptake assay using GH₄C₁ cells for the separation of natural product extracts and for the primary detection of their calcium antagonistic components. The reliability of the procedure was first established with a reference solution consisting of pure compounds with a known effect on the Ca²⁺ uptake. No loss of activity was observed to occur after HPLC micro-fractionation. Extracts of Peucedanum palustre and Pinus sylvestris, showing high and no inhibition of Ca²⁺ uptake as total extracts, respectively, were analysed and the inhibitory activity of the P. palustre extract could be traced to two components, identified as columbianadin and isoimperatorin. As expected, no significant inhibition was observed with the micro-fractionated P. sylvestris samples. In summary, the procedure was found to be applicable for primary detection of calcium antagonistic components in complex matrices and to significantly reduce the time previously needed for bioactivity-guided isolation.     

Linear spaces on v points with v−2 mutually intersecting long lines

Finite linear spaces on v points with v–2 mutually intersecting long lines are completely characterized.Dedicated to Professor Giuseppe Tallini on the occasion of his 60^th birthday.Work supported by Italian M.P.I. 8nd by GNSAGA of CNR     

A rare mu-hydroxo-bridged species. synthesis, structure, and properties of mu-hydroxo(tetraphenylporphyrinatomanganese(III))(phthalocyaninato(azido)chromium(III)), [(TPP)Mn-O(H)-CrPc(N3)

A novel ditetrapyrrolic, heteroleptic, and heterometallic (Mn-Cr) mu-hydroxo-bridged complex has been prepared, and its structural and general properties have been studied. The species mu-hydroxo(tetraphenylporphyrinatomanganese(III))(phthalocyaninato(azido)chromium(III)), [(TPP)Mn-O(H)-CrPc(N3)], isolated as a chloronaphthalene (ClNP) solvate, has been structurally characterized by single-crystal X-ray work. The two (TPP)Mn and CrPc(N3) fragments are held together by the bridging mu-hydroxo ion with long Mn-O [1.993(5) A] and Cr-O [1.976(5) A] bond distances and a Mn-O(H)-Cr angle of 163.7(3) degrees . The five-coordinate Mn center in the (TPP)Mn fragment is displaced from the TPP rigorously planar central N4 core by 0.128 A, and the environment is typical of a Mn(III) high-spin site. The six-coordinate Cr(III) in the CrPc(N3) moiety lies practically in the plane of the phthalocyanine macrocycle (displacement toward the azido group: 0.054 A). The average Mn-N(pyr) and Cr-N(pyr) bond distances are 2.011(6) and 1.982(6) A, respectively, and the Mn-Cr bond distance is 3.929(2) A. The porphyrin and phthalocyanine rings are in an almost eclipsed position [5.16(2) degrees ], and the mean planes of the two macrocycles form a dihedral angle of 5.79(4) degrees. Crystal data for [(TPP)Mn-O(H)-CrPc(N3)].2ClNP, C76H45CrMnN15O.2C10H7Cl: a = 16.645(3) A, b = 17.692(4) A, c = 25.828(5) A, alpha = 90 degrees , beta = 98.79(3) degrees , gamma = 90 degrees , space group P2(1)/c (No. 14), V = 7517(3) A(3), Z = 4, R1 = 0.086, and wR2 = 0.267. IR and UV-vis-near-IR spectral and room temperature magnetic susceptibility data of the [Mn-Cr] species are also presented.     

Proteome analysis of conditioned medium from cultured adult hippocampal progenitors

It is known that proliferation and survival of neural stem/progenitor cells in vitro not only depend on exogenous factors, but also on autocrine factors secreted into the conditioned medium. It is also well known that the identification of bioactive proteins secreted into the conditioned medium poses a substantial challenge. Recently, neural stem/progenitor cells were shown to secrete a survival factor, cystatin C, into the conditioned medium. Here, we demonstrate an approach to identify other low molecular weight proteins in conditioned medium from cultured adult rat hippocampal progenitor cells. A combination of preparative two-dimensional gel electrophoresis (2-DE) and mass spectrometry was utilized in the analysis. We were able to identify a number of proteins, which include Rho-guanine nucleotide dissociation inhibitor 1, phosphatidylethanolamine binding protein (PEBP), also termed Raf-1 kinase interacting protein, polyubiquitin, immunophilin FK506 binding protein 12 (FKBP12) and cystatin C. The presence of PEBP and FKBP12 in conditioned medium was confirmed immunologically. All nestin-positive progenitor cells showed immunoreactivity for antibodies against PEBP and FKBP12. To our knowledge we are the first to use this preparative proteomic approach to search for stem cell factors in conditioned medium. The method could be used to identify novel bioactive proteins secreted by stem/progenitor cells in vitro. Identification of bioactive proteins in vitro is of potential importance for the understanding of the regulatory mechanisms of the cells in vivo.     

Amorphous drug nanosuspensions. 3. Particle dissolution and crystal growth

In the present paper, we have studied particle dissolution and crystal growth of the poorly water soluble drug felodipine, using fluorescence as a probe for the amount of crystalline material. Dissolution kinetics is essentially diffusion-controlled, while the rate of crystal growth is significantly slower compared to the diffusion-controlled limit. The deviation from diffusion control was characterized by the effective length, lambda, related to the kinetics of a surface integration process. Amorphous nanoparticles may be highly unstable in the presence of small amounts of crystalline particles. This is due to the fact that the molecular solubility from the amorphous nanoparticles often is at least an order of magnitude higher than the corresponding crystalline solubility. In a mixed system where crystalline nanoparticles have been added to an amorphous nanosuspension, the bulk will have a monomer concentration intermediate between the amorphous and crystalline solubilities, and is thus supersaturated with respect to the crystalline particles while being undersaturated with respect to the amorphous particles. As a consequence, the amorphous particles spontaneously dissolve, while crystalline particles grow, in a combined process which is similar to Ostwald ripening. By knowing the parameters describing dissolution and crystal growth, respectively, it was possible to simulate the outcome of controlled seeding experiments, where a small amount of crystalline nanoparticles was added to a dispersion of amorphous nanoparticles. A good agreement between model calculations and experiments was obtained including how the crystal growth rate varied with the amounts of added crystalline seeds.     

Iron stains on paper. Can electrophoretic removal become an effective alternative to chemical cleaning?

Abstract

Research in restoration and conservation is directed vs. more sustainable working materials, methods and technologies. Electrophoretic removal, from porous material, of undesired stains due to charged species is theoretically an interesting alternative to chemical cleaning methods, but the lack of specific and comprehensive research work leads to controversial opinions about the efficiency and the needed harmfulness for the treated objects. In this work paper, samples with artificial rust stains were subjected to electrophoretic cleaning treatments in mineral water as electrolyte. Treatments were carried out either in a bath by complete sample immersion between the distanced electrodes or by sample wetting and sandwiching between the electrodes. Evaluation of cleaning efficiency and treatment effects was based on colour change measurements (image analysis of scanned paper samples before and after the treatment and by colorimetric data via spectrophotometric measurements), investigation of morphological changes by SEM observations and folding endurance measurements.     

Application of MII 2MV 2(acac)2(OMe)12 Derivatives in Sol-Gel Preparation of Oxide and Oxide Nanocomposite Materials for Catalysis

Hydrolysis of M^II ₂M^V ₂(acac)₂(OMe)₁₂, M^II=Co or Ni and M^V=Nb or Ta, in dry toluene, subsequent evaporation of the solvent, and heating to 500°C, provides access to a catalytically active oxide. The thermogravimetry (TG) analyses of the thermal behaviour of the hydrolysed alkoxides show three distinct steps. The first weight loss occurs at 120°C, the second at 390°C, and the third at 480°C. The weight is constant at 67% of original weight from 480 to 900°C. The powder X-ray patterns of the Co-Ta hydrolysed alkoxide show that powder heated to 500°C is amorphous but powder heated to 900°C revealed the presence of an equimolar mixture of Co^IITa₂O₆ and Co₄ ^IITa₂O₉. Gelation and further transformation on thermal treatment were found to occur in the same way for Co₂Ta₂(acac)₂(OMe)₁₂, Ni₂Ta₂(acac)₂(OMe)₁₂, and Co₂Nb₂(acac)₂(OMe)₁₂.Interaction of Co₂Ta₂(acac)₂(OMe)₁₂ solution with NaY 12 Å zeolite was found to be an exothermic reaction providing access to a nanocomposite compound. The latter has been investigated with the aid of EXAFS spectroscopy. The interaction with NaY 12 Å zeolite was found to occur in the same way for Co₂Nb₂(acac)₂(OMe)₁₂.