A14-[125I]monoiodoinsulin purified by different high-performance liquid chromatographic procedures and by polyacrylamide gel electrophoresis: preparation, immunochemical properties and receptor binding affinity

Reversed-phase high-performance liquid chromatography (RP-HPLC) allows the rapid separation of A14-[125I]monoiodoinsulin directly from the iodination mixtures. It remains to be clarified, however, whether the RP-HPLC chromatographic conditions affect the properties of the purified tracer. In this study we prepared A14-[125I]insulin purified by polyacrylamide gel electrophoresis (PAGE) and by three different RP-HPLC mobile phases containing, respectively, ammonium acetate, sodium perchlorate and trifluoroacetic acid. The binding characteristics of all these tracers were examined using an insulin antiserum and insulin cell receptors. The specific radioactivity corresponded to the theoretical maximum for the RP-HPLC-purified tracers and was significantly lower for the PAGE-purified tracers. Significant differences were found in the binding of different tracers to the insulin antiserum: maximum binding ranged from 94 to 99% and was significantly lower for tracers purified by RP-HPLC eluents B and C; antiserum dilution giving 50% tracer binding was lower for tracers purified by RP-HPLC eluent B. The four insulin derivatives showed no difference in non-specific precipitation and in the affinity constant values calculated from the Scatchard analysis. No significant difference was found in the binding of the four insulin derivatives to the human-cultured IM-9 lymphocytes and to the human circulating monocytes. In conclusion, the present work demonstrates that the immunological properties of the A14-[125I]monoiodoinsulin purified by RP-HPLC may be partially affected by the composition of the mobile phase. In order to obtain a fully potent A14-[125I]insulin derivative and to have the possibility of comparing data from different laboratories, the chromatographic conditions must be taken into account.     

Effects of Tributyltin(IV) Chloride Exposure on Larvae of Ciona intestinalis (Urochordata): An Ultrastructural Study

The effects of tributyltin(IV) chloride (TBT chloride) have been tested on embryos of the ascidian Ciona intestinalis , at two different stages of development: (1) before hatching (coiled larval stage) and (2) 2 h after hatching (swimming larval stage). In vivo observations carried out with a light microscope showed that embryos at the coiled larval stage did not hatch following exposure to TBT chloride. Severe anomalies in the swimming larva, mainly concerning the morphology of the tail, which appeared twisted and squatter than in the controls, were observed. Such anomalies were also found at a functional level, i.e. contractile movements were poor so that the larvae appeared motionless. Ultrastructural investigations carried out using a transmission electron microscope (TEM) evidenced that the muscle cells were damaged. Modifications mainly occurred in mitochondria and myofibrils, i.e. the energetic and enzymic centres. This fact is probably the main cause of the loss of mobility of the larvae.     

Multifunctional Small Molecules as Potential Anti-Alzheimer’s Disease Agents

Alzheimer’s disease (AD) is a severe multifactorial neurodegenerative disorder characterized by a progressive loss of neurons in the brain. Despite research efforts, the pathogenesis and mechanism of AD progression are not yet completely understood. There are only a few symptomatic drugs approved for the treatment of AD. The multifactorial character of AD suggests that it is important to develop molecules able to target the numerous pathological mechanisms associated with the disease. Thus, in the context of the worldwide recognized interest of multifunctional ligand therapy, we report herein the synthesis, characterization, physicochemical and biological evaluation of a set of five (1a–e) new ferulic acid-based hybrid compounds, namely feroyl-benzyloxyamidic derivatives enclosing different substituent groups, as potential anti-Alzheimer’s disease agents. These hybrids can keep both the radical scavenging activity and metal chelation capacity of the naturally occurring ferulic acid scaffold, presenting also good/mild capacity for inhibition of self-Aβ aggregation and fairly good inhibition of Cu-induced Aβ aggregation. The predicted pharmacokinetic properties point towards good absorption, comparable to known oral drugs.     

Radium removal from aqueous solutions by variously supported ligands

A set of ligands loaded on various supports have been tested to remove radium from aqueous solutions. Crown ethers have demonstrated inefficiency in all cases, while open chain ligands (podands) have shown satisfactory distribution coefficients and uptake rates in particular conditions. Hypotheses to explain the phenomenon are briefly discussed.     

Flow reversal in a simple dynamical model of turbulence

In this Letter, we study a simple hydrodynamical model showing abrupt flow reversals at random times. For a suitable range of parameters, we show that the dynamics of flow reversal is accurately described by stochastic differential equations, where the noise represents the effect of turbulence.     

On the Mellor-Durbin theory of marine thermocline

Summary The evolution of the marine thermocline is studied by using some algebraic relations derived by Mellor and Durbin. In particular, a simple algebraic way to compute various turbulent quantities from experimental data is illustrated.

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Riassunto Si studia l'evoluzione del termoclino marino partendo dal modello ottenuto da Mellor e Durbin chiudendo al secondo ordine le equazioni della turbolenza. In particolare, si mostra un metodo che fornisce informazioni riguardanti le grandezze turbolente tramite soluzione di equazioni algebriche tratte dal modello. Si applica infine tale metodo a due serie di dati sperimentali.

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Резюме Исследуется эволюция морского термоклика, используя некоторые алгебраические соотношения выведенные Меллором и Дурбином. В частности, предлагается простой алгебраический способ для вычисления различных турбулентных из зкспериментальных данных.

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Research sponsored by C.N.R. ?Progetti Finalizzati Oceanografia?.     

Mathematical basis of approximate MO theories: Origin of mulliken's magic formula

The mathematical basis for the Ruedenberg's and Mulliken's approximations is given in a general framework.