The stimulatory effect of heavy metal cations on proliferation of aortic smooth muscle cells

Heavy metal cations Cd2+, Pb2+, and Hg2+ were added to substitute for Ca2+ in culture media to study their effect on the relationship between CaM and the proliferation of cultured rabbit aortic smooth muscle cells (ASMC). It was found that all the heavy metal cations studied stimulated the proliferation of ASMC in varying degrees, increased the CaM content in cells at late G1 stage and decreased the activity of cAMP PDE. These results suggest that the adverse effect of heavy metals may be related to the pathogenesis of atherosclerosis and hypertensive disease.     

Polarographlc analysis for corticosteroids: Part 5. Reduction mechanism of halogen-containing corticosteroids and analysis of some preparations

In fluprednisolone and chloroprednisone acetate, the polarographic reduction of the carbon—halogen bond in position 6 occurs first. The carbanion—enolate formed is reduced at the dropping mercury electrode at more negative potentials than the conjugate acid. Controlled potential electrolysis at a mercury pool electrode where the carbanion—enolate can be protonated, yields the unsaturated ketone. Polarographic reduction of clobetasol-17-propionate and of clobetasone-17-butyrate results in cleavage of the C—Cl bond in the side-chain. This process is followed by reduction of the α,β-unsaturated ketone in the A-ring. Analytical methods for the determination of these compounds in ointments, creams and eye/ear drops gave results with standard deviations of 1–2%.     

Structural isomerism of mono- and sesquiterpenoid skeletons

A generator of chemical structures (CONGEN) has been utilized to investigate two aspects of the structural isomerism of mono- and sesquiterpenoid skeletons: (1) the scope of possible isomers under various structural constraints; and (2) the scope of possible isomers based on a mechanistic model which allows interactive exploration of reactions of formation and interconversion. The possibilities, even under severe constraints, are many more than the structural types commonly encountered in natural. These results indicate the potential danger of structural assignment based in part on biogenic grounds.     

Structure in metastable peaks arising from reactions in which[C3H3]+ ions are produced

The metastable peak resulting from the fragmentation of [C₇H₇]²⁺? ions fram a variety of sources shows structure due to the presence of two reactions releasing different amounts of translational energy. The translational energy differences has been measured as 0.52 ± 0.04eV and is thought to be due to the formation of product ions of different structure via competing reactions from a single transition state. The possible structures of these ions are discussed, and it is proposed that the effect observed is due to the formation of [C₃H₃]⁺ ions in two forms, cyclopropenyl and proparg1. The metastable singly charged ions which also lead to product ions of formula [C₃H, ₃]⁺.     

Absorption of amines on cation exchange resins

All the amines studied are absorbed in excess of the exchange capacity bysulfonated polystyrene resins from aqueous solutions; the absorption is greatest with benzylamine, whose molecular structure is the closest to that of the monomer of the resin. The absorption is greater, then less the crosslinking of the resin, and it is influenced by the electrostatic field of the resin cations. There is no excess absorption from solvents such as alcohols, acetic acid or dioxane. The absorption characteristics of amines are sufficiently different that separations by elution chromatography on cation exchange resins are possible. Two such separations have been demonstrated. For quantitative analytical use, however, it would be wise to use very fine mesh resins on account of the slowness of diffusion of large amine molecules within the resins.     

Neue Wege und Ergebnisse der Röntgenspektroskopie

Zusammenfassung Es wird eine Röntgenröhre mit Durchstrahlanode zur bequemen Außenanregung von Röntgenspektren beschrieben. Mit ihrer Hilfe konnte die Frage der sekundären Erregung des ₃-Satelliten im Falle des Chroms geklärt werden. Ferner eignete sich die Röhre zusammen mit vielkristallinen Beugungsgittern gut für ein einfaches spektralanalytisches Verfahren der Elemente Ti (22) bis Zn (30). Schließlich konnte gezeigt werden, daß man bei Verwendung vielkristalliner Beugungsgitter unter Ausnützung bekannter Gesetzmäßigkeiten unter Umständen eine Genauigkeit der Wellenlängenmessung erreicht, die jene mit klassischen Einkristallspektrographen übliche übertrifft. Diese hohe Genauigkeit reicht aus, die geringfügigen Einflüsse chemischer Bindung auf dieK ₁-Linie von Eisen und Kobalt meßbar zu machen.

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Summary A röntgen tube is described with a radiating anode for the convenient external excitation of röntgen spectra. With its aid, it was possible to explain the problem of the secondary activation of the ₃-satellites in the case of chromium. Furthermore, the tube was well suited for use, in conjunction with multicrystalline diffraction gratings, for a simple spectral analytical procedure for the elements Ti (22) up to Zn (30). Finally, it could be shown that with use of multicrystalline diffraction gratings and employment of known regularities, it is possible to attain an accuracy of the measurement of the wave length exceeding that secured with the classic monocrystal spectrograph. This high accuracy is sufficient to bring into the range of measurement the slight influences of chemical binding on theK ₁-line of iron and cobalt.

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Résumé On décrit un tube à rayonsX avec une anode rayonnante pour l'excitation externe des spectres de rayonsX. En employant ce tube il est possible de résoudre le problème de l'excitation secondaire des satellitesa ₃ dans le cas du chrome. En outre, ce tube convient très bien pour être employé avec des réseaux de diffraction à cristaux multiples; on a ainsi un procédé simple d'analyse des éléments du titane (22) au zinc (30). Finalement on a pu montrer qu'en employant des réseaux de diffraction à cristaux multiples et à partir de régularités connues, on peut atteindre une précision dans la mesure des longueurs d'onde qui dépasse celle qu'on atteint habituellement avec un spectrographe à cristal unique. Cette précision élevée suffit pour qu'on puisse mettre en évidence la faible influence de la liaison chimique sur les raiesK ₁ du fer et du cobalt.

     

Radiolysis of aqueous solutions of cobalt(II) and cobalt(III)

Radiolysis of aqueous solution of di and trivalent cobalt with 1:2 (bis) carboxymethylaminodiethyltetraacetic acid (EGTA) was investigated, both in absence and in presence of oxygen. A radiolytic mechanism has been proposed. It has been shown that the degradation at the ligand of the chelate is due to OH only.     

Spektroskopische Untersuchungen an Phenoxydimethylfloursilanen

Spectroscopie Investigations on R? C₆H₄O(CH₃)₂SiF Compounds The i.r. and Raman spectra of a number of R? C₆H₄O(CH₃)₂SiF compounds (R = H, CH₃, CH₃O, Cl, Br, NO₂, NH₂) have been recorded. The intramolecular and intermolecular interactions were discussed by means of ν SiF, ν Si? O? (C), ν C? O? (Si) and ν_s SiC₂ vibrations.     

On the synthesis and animation of 5-chloro-and 5-bromo-1,7-naphthyridine

A new synthesis of 5-chloro- and 5-bromo-1,7-naphthyridine, using 8-amino-1,7-naphthyridine as starting material is described. On amination with potassium amide in liquid ammonia, the 5-bromo compound undergoes a tele-amination into 8-amino- and 2-amino-1,7-naphthyridine and a Chichibabin reaction yielding 8-amino-5-bromo-1,7-naphthyridine. The reaction with the 5-chloro compound occurs at a much lower rate than the 5-bromo compound and only gives 8-amino-5-chloro-1,7-naphthyridine in a small yield. Convincing ¹H-nmr evidence is presented, showing that the 5-bromo- and 5-chloro-1,7-naphthyridine give addition of the amide ion at position 8 and that the 5-chloro compound also gives addition at position 2.     

Aspects of stereochemistry—I Properties and reactions of some diols

The extent of intramolecular hydrogen-bonding, as determined by infra-red spectroscopy in the hydroxyl stretching region, in certain vicinal diols of cyclohexane, cyclopentane, tetrahydropyran and tetrahydrofuran and in related compounds provides evidence for the stabilities of different conformations. In certain compounds these stabilities can be affected by hydrogen bonding from a substituent hydroxyl group to a ring oxygen. Additional evidence is provided in the case of the tetrahydropyran diols by [M]_D values. The rate of reaction of the vicinal diols of these cyclic systems with glycol splitting reagents, and their zone electrophoretic mobility in an alkaline borate buffer is influenced by the presence of a ring oxygen.