Synthesis and biological evaluation of <Superscript>99m</Superscript>Tc labeled aryl piperazine derivatives as cerebral radiotracers

The aim of this study is to develop cerebral radiotracers for central nervous system receptors imaging. The synthesis, characterization and biological evaluation of two aryl piperazine ^99mTc-radiocomplexes based on the piano stool motif [CpM(CO₃)] (Cp = cyclopentadienyl, M = ^99mTc/Re) is reported. The ^99mTc-radiocomplexes were obtained quickly (time < 5 min) with high radiochemical yields. The ^99mTc-radiocomplexes characterized by high performance liquid chromatography comparison with the rhenium surrogates have both a suitable lipophilicity and are able to cross the blood brain barrier with 0.43 ± 0.05 and 1.96 ± 0.06% ID/g of brain uptake, at 10 min post injection.     

Synthesis and crystal structure of some 3,5-pyrazolidinediones

Syntheses of various derivatives of 3,5-pyrazolidenedione are reported. This includes 4-arylidene (alkylidene or aralkylidene)-3,5-pyrazolidinediones, which on epoxidation gave unreported oxiranes. The syntheses of these derivatives were based on either the Knoevenagel reaction of carbonyl derivatives with 3,4-pyrazolidinedione or cyclization of arylidene (alkylidene) malonic acid hydrazide with glacial acetic acid. 4-Arylazo-3,5-pyrazolidinedione derivatives were also prepared by coupling of aryldiazonium salts with 3,5-pyrazolidinedione or cyclization of arylazomalonic acid hydrazide. Reduction of 4-benzylidene derivatives gave the corresponding benzyl derivatives. The structure of the new products was confirmed by elemental and spectral analyses and X-ray crystallography.     

Kinetics of Oxidation of L‐Cysteine by trans‐ and cis‐CoIII and FeIII Complexes based on α‐ and γ‐Diimine Schiff Base Ligands

Kinetics of oxidation of L ‐cysteine by Co^III and Fe^III complexes based on α‐ and γ‐diimine Schiff base ligands were studied in aqueous solution. Pairs of trans and cis isomers of the metal complexes were used in the studies. Kinetic measurements were performed at 25 °C and constant pH and ionic strength under pseudo‐first order condition, in which the concentration of cysteine was around two orders of magnitude greater than that of the metal complex. The observed rate constant was obtained by following the change in absorbance of the reaction mixture with time at a predetermined wavelength. The overall rate constant and order of the reaction with respect to cysteine and metal complex were determined. For both metal ions studied, the oxidation rate constant for the trans isomer was higher than that for the cis isomer. This was attributed to the contribution of the steric factor and the trans effect. The effects of substituents and the nature of the metal ion on the reaction rate are discussed.     

Deuteration of Water Enables Self‐Organization of Phospholipid‐Based Reverse Micelles

Phospholipid‐based reverse micelles are composed of branched cylinders. Their branching points are known to attract themselves and to slide along branches. The rate of this sliding is governed by the lifetime of H(D)‐bonded water bridges between phospholipid molecules. This lifetime is increased when the water is deuterated. On condition that the water contains at least 40 D atoms %, water/dipalmitoylphosphatidylcholine (DPPC)/deuterated pyridine reverse micelles with the composition 1.1:1:250 (v/v) have been shown to self‐organize into a liquid crystal in the 310–316 K temperature range. The mechanism of this self‐organization is unraveled by following the FTIR and ¹H NMR spectra of more concentrated micelles upon heating. During the preparation of micelles, pyridine‐(D⁺)H⁺ ions are formed. They give rise to hydron transfers, under the influence of the DPPC electric charges, evidenced by two broad FTIR absorptions above (BB1) and below (BB2) the ν(C? O) stretch. These hydron transfers occur along strong (D⁺)H⁺ bonds of pyridinium ions with pyridine (BB1) and DPPC C?O groups (BB2). The proton transfers at the interface of micelles, relayed in the continuous pyridine medium, create a tenuous link between separated micelles, thus facilitating their organization. Upon heating, DPPC heads shrink and DPPC chains expand to make wedge‐shaped DPPC molecules. The micelles then change in shape: cylinders constrict and enclosed water drifts towards branching points, which swell. Branching points of neighboring micelles come into contact. Due to the deuteration of water these contacts are prolonged and H bonds are formed between DPPC molecules located in each branching point. Upon storage at 39 °C, these branching points fuse. The lateral diffusion of DPPC molecules becomes free, as evidenced by a narrowing of all ¹H NMR resonances. Upon further heating, reorganization into a liquid crystal occurs.     

Étude structurale de britholite au césium Sr7La2Cs(PO4)5(SiO4)F2

Several studies demonstrated the ability of britholites to retain radionuclides such as the caesium and actinides. Therefore, three compounds with formulas Sr₈LaCs(PO₄)₆F₂, Sr₇La₂Cs(PO₄)₅(SiO₄)F₂ and Sr₂La₇Cs(SiO₄)₆F₂, were prepared by solid state reaction. However, it seems that only the mono-silicated composition was obtained in a pure state. In this present work, the X-ray diffraction and magnetic nuclear resonance have been used to investigate the structure for this composition. The results showed that in fact this phase was not pure, but it was mixed with a secondary phase, SrLaCs(PO₄)₂. The refinement by the Rietveld method allowed also to precise the distribution of La³⁺ and Cs⁺ ions between the two cationic sites of the apatite.     

Characterization and de novo sequencing of snow crab tropomyosin enzymatic peptides by both electrospary ionization and matrix‐assisted laser desorption ionization QqToF tandem mass spectrometry

The protein tropomyosin (TM) is a known major allergen present in shellfish causing frequent food allergies. TM is also an occupational allergen generated in the working environment of snow crab (Chionoecetes opilio) processing plants. The TM protein was purified from both claw and leg meats of snow crab and analyzed by electrospray ionization and matrix‐assisted laser desorption/ionization (MALDI) using hybrid quadruple time‐of‐flight tandem mass spectrometry (QqToF‐MS). The native polypeptide molecular weight of TM was determined to be 32 733 Da. The protein was further characterized using the ‘bottom‐up’ MS approach. A peptide mass fingerprinting was obtained by two different enzymatic digestions and de novo sequencing of the most abundant peptides performed. Any post‐translational modifications were identified by searching their calculated and predicted molecular weights in precursor ion spectra. The immunological reactivity of snow crab extract was evaluated using specific antibodies and allergenic reactivity assessed with serum of allergic patients. Subsequently, a signature peptide for TM was identified and evaluated in terms of identity and homology using the basic local alignment search tool (BLAST). The identification of a signature peptide for the allergen TM using MALDI‐QqToF‐MS will be critical for the sensitive and specific quantification of this highly allergenic protein in the work place. Copyright © 2010 John Wiley & Sons, Ltd.     

Snail Hepatopancreatic Lipase: A New Member of Invertebrates Lipases' Group

Higher animal's lipases are well characterized; however, much less is known about lipases from mollusks. A lipolytic activity was located in the land snail (Eobania vermiculata) digestive glands (hepatopancreas), from which a snail digestive lipase (SnDL) was purified. Pure SnDL has a molecular mass of 60 kDa; it does not present the interfacial activation phenomenon. It was found to be more active on short-chain triacylglycerols than on long-chain triacylglycerols. The NH₂-terminal sequence of the SnDL shows 66% of identity with the 17 NH₂-terminal amino acids of a putative lipase from sea urchin (Strongylocentrotus purpuratus). No sequence identity was found with known lipases. Interestingly, neither colipase nor bile salts were detected in the snail hepatopancreas. This suggests that colipase evolved in vertebrates simultaneously with the appearance of an exocrine pancreas and a true liver which produces bile salts. Altogether, these results suggest that SnDL is a member of a new group of digestive lipases belonging to invertebrates.     

Recent developments in microbial inulinases

Microbial inulinases are an important class of industrial enzymes that have gained much attention recently. Inulinases can be produced by a host of microorganisms, including fungi, yeast, and bacteria. Among them, however, Aspergillus sp. (filamentous fungus) and Kluyveromyces sp. (diploid yeast) are apparently the preferred choices for commercial applications. Among various substrates (carbon source) employed for their production, inulin-containing plant materials offer advantages in comparison to pure substrates. Although submerged fermentation has been universally used as the technique of fermentation, attempts are being made to develop solidstate fermentation technology also. Inulinases catalyze the hydrolysis of inulin to d-fructose (fructose syrup), which has gained an important place in human diets today. In addition, inulinases are finding other newer applications. This article reviews more recent developments, especially those made in the past decade, on microbial inulinases—its production using various microorganisms and substrates. It also describes the characteristics of various forms of inulinases produced as well as their applications.     

A new method for the isolation and estimation of Furan-2,5-dicarboxylic acid in human urine

Summary A new, concise and efficient method of isolation and estimation of F. D. A. avoiding heating with acids, has been devised.Inositol and calcium gluconate when added to urine and subjected to the old method of isolation of F. D. A. result in no increase in the amount of F. D. A. This indicates that the increase in the output of this acid obtained before⁴ was a process within the body itself.Metabolic experiments with inositol and calcium gluconate adopting the new method gave a 3–4 fold increase in the F. D. A. output confirming that this increase is anin vivo process.

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Zusammenfassung Eine neue, genaue Methode zur Isolierung und Bestimmung von Furandicarbonsäure (F. D. C.) ohne Erhitzen des angesäuerten Untersuchungs-materials wurde ausgearbeitet. Werden Inosit und Calciumgluconat dem Harn vor Aufarbeitung nach der alten Methode zugesetzt, so führt dies zu keiner Erhöhung der F. D. C.-Menge. Die früher beobachtete Vermehrung der F. D. C.-Menge ist also die Folge von Vorgängen innerhalb des Organismus. Stoffwechselexperimente mit Inosit und Calciumgluconat mit der neuen Methode zeigen eine drei bis vierfach gesteigerte F. D. C.-Ausscheidung und bestätigen damit deren vermehrte Bildung in vivo.

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Résumé On a imaginé une nouvelle méthode rapide et efficace pour isoler et doser le F. D. A. en évitant le chauffage avec les acides. L'inositol et le gluconate de calcium, ajoutés à l'urine et soumis à la vieille méthode d'isolement du F. D. A. ne produisent pas de surcharge sur la quantité de F. D. A. Ce fait indique que l'augmentation du rendement de cet acide, obtenue auparavant, était un processus dans le corps humain lui-même.Des expériences sur le métabolisme avec l'inositol et le gluconate de calcium, en adoptant la nouvelle méthode, ont donné une augmentation de trois à quatre fois le rendement en F. D. A., ce qui confirme que cette augmentation se produitin vivo.