Protection of Erythrocytes Against Organometals-Induced Hemolysis

The hemolytic toxicity of tributyllead (TBL) and triphenyllead (TPhL) chlorides and its prevention by dithiotreitol (DTT), diethylenetriaminepentamethylenephosphonic acid pentasodium (PMP) and sodium disulfide (Na2S) was studied. It was found that both TBL and TPhL efficiently hemolyzed pig erythrocytes when used in micromolar concentrations; tributyllead chloride being about twice more efficient than triphenyllead chloride. The hemolytic efficiency of these compounds was blocked by PMP, DTT and Na2S in a concentration-dependent manner. However, significant differences in anti-hemolytic efficiency of these compounds were found. Namely, DTT and Na2S were very efficiently protecting erythrocytes against the action of organoleads, while the PMP protection was weak. Also, differences between DTT and Na2S protective efficiency were found. They more efficiently prevented erythrocyte hemolysis by TPhL than by TBL. Moreover, erythrocytes were better protected against the action of TBL by Na2S than by DTT. Such differentiation may be connected with possible differences in localization of the organolead compounds and protective agents in the erythrocyte membrane. To check these possibilities a series of experiments was performed using the fluorescence technique and various fluorimetric probes. These measurements enabled to determine fluidity changes induced in erythrocyte membranes by the organoleads and the protective compounds and to formulate some remarks concerning the differences in the mechanism of interaction of the organoleads with these membranes.     

The conformation of t-butyl 2-methoxy-5, 6-dihydro-2 H-pyran-6-carboxylates and 6,6′- disubstituted 2-methoxy-5,6-dihydro-2H-pyran derivatives on the basis of 1H and 13 C NMR spectra

The ¹H and ¹³C NMR spectra of trans- and cis-tert-butyl 2-methoxy-5,6-dihydro-2H-pyran-6-carboxylates (1 and 2) and 6,6′-disubstituted 2-methoxy-5,6-dihydro-2H-pyrans (3-7) have been recorded. HH and CH coupling constants are discussed in terms of the ¹H₆?⁶H₁ conformational equilibrium. It has been found that 1 occurs exclusively in the ¹H₆ conformation, whereas its cis isomer, 2, exists in an equilibrium of both half-chair forms. 6,6′-Disubstituted 2-methoxy-5,6-dihydro-2H-pyrans 3-6 display spectral and conformational behaviour similar to that of 1, whereas 7 resembles 2 in this respect.     

Partialsynthetische Aristolochiasäuren und Analoge 4. Mitt.: 3,4,5,6-Tetramethoxy-1,8-dinitrophenanthren, 3,4,5,6-Tetramethoxy-8-nitro- und 3,4,5,6-Tetramethoxy-8,10-dinitrophenanthren-1-carbonsäuren

An aporphine alcaloid of the bulbocapnine-type (isocorydine) was used for the synthesis of aristolochic acid analogs. By degradation and nitration of the reaction product three new compounds, a dinitrophenanthrene, a nitro- and a dinitrophenanthrene acid were obtained and their structures were established.

     

Properties of Nanotitanium for Potential Medical Applications

Summary : Two titanium-Grade2 (a course-grained in the received state and nanostructured after hydrostatic extrusion) were examined wear and corrosion tests. Passive oxide layers formed on the surface of both materials had a thickness of about 6 nm and the same chemical composition. The corrosion resistances measured in a 0.9% NaCl solution were comparable. The friction tests show that nano-grained Ti is suitable for use in the tribological par with UHMWPE.     

用大孔凝胶阴离子交换剂从含亚氨二醛酸试液中分离镧、镨化合物

在采用阴离子交换剂从含氨基多羧酸试液中分离稀土的研究中 ,发现在醋酸和亚氨二醋酸试液中 ,稀土元素与亚氨二醋酸的亲合力顺序是 :Dy3 >Ho3 >Gd3 >Eu3 >Er3 >Y3 >Sm3 >Tm3 >Nd3 >Pr3 >>La3 。根据镧亲合力最小的特点 ,有可能将镧与其他稀土分离 (例如Pr)。在本研究中 ,采用了强碱性凝胶阴离子交换剂Dowex 1× 8(1型 )和Dowex 2× 8(2型 )以及强碱性大孔阴离子交换剂DowexMSA 1。研究表明 ,大孔离子交换剂其海棉状基质 ,孔径大于其分子直径 ,故大离子的交换速度快。另外 ,大孔凝胶阴离子交换剂可在亚氨二醋酸试液中将La ,Pr分离而提纯出镧化合物。     

Kinetics and mechanism of sensitized photooxidation of tetramethylammonium salt of 2-(phenylthio)acetic acid in solution: Steady-state and flash photolysis studies

The mechanism for the photo-induced oxidation of the tetramethylammonium salt of 2-(phenylthio)acetic acid was elucidated. The photosensitizer was the benzophenone triplet in acetonitrile solutions. Time-resolved absorption spectra and kinetics were used to follow the intermediates which included the triplet of benzophenone, the ketyl radical of benzophenone, and an ion pair consisting of a radical anion of benzophenone and a tetramethylammonium cation. Rate constants for the growth and decay of the transients were determined along with the quantum yields of the transients. The intermediacy of other radicals was inferred by the products observed following steady-state photolysis. Quantum yields were also determined for photoproducts resulting from the steady-state irradiation. The mechanism was proposed that rationalized the quantitative observations. Of particular note was how the nature of the counter ion effected the secondary reactions of the radicals and the radical ions.     

Benzofuran systems. Regioselective bromination and some other reactions of 1-(3-benzofuranyl)-2-phenylethanones

1-[3-(2-Alkylbenzofuranyl)]-2-(3,5-dibromo-4-hydroxyphenyl)ethanones 5a,b and 1-[3-(2-alkylbenzofuranyl)-2-(3-bromo-4-methoxyphenyl)ethanones 3a,b were readily prepared by selective bromination of hydroxy 1a,b and methoxy 1c,d ethanones, respectively. A successful method of O-alkylamination of 5a with N-(2-chloroethyl)-N,N-diethylammonium chloride to 6a by a two-phase reaction under phase transfer conditions has been applied. Lithium aluminium hydride reduction of the carbonyl group of 1b to carbinol 4b was carried out in good yields.