Further studies on the ability of different metal salts to influence the DNA synthesis of human lymphoid cells

In a further study on the ability of different metal salts to influence the DNA synthesis of human lymphoid cells, aluminum chloride, beryllium chloride, cadmium chloride, cupric sulfate, ferric chloride, manganese chloride, palladium chloride, platinum chloride and silver nitrate, were tested regarding effect on thymocytes and peripheral blood lymphocytes in children. At certain concentrations in the range of 10(-4)-10(-5)M, all tested compounds but aluminum chloride and ferric chloride, were inhibitory, the latter compounds inhibited at 4.8 X 10(-3)M. A slight stimulation mainly on the thymocytes was obtained with beryllium chloride, cadmium chloride, palladium chloride, platinum chloride and silver nitrate, at certain concentrations in the range of 10(-5)-10(-6)M, while ferric chloride gave a slight stimulation at 1.2 X 10(-3)M. Thus, the tested metal salts should be suitable for use in lymphocyte transformation tests for diagnosis of contact allergy.

Some mixed-ligand palladium(II) complexes of 2,2'-bipyridine and amino acids as potential anticancer agents

Eight new palladium complexes of the formula [Pd(bipy)(AA)]Cl 1 or 2 H2O (where bipy is 2,2'-bipyridine and AA is an anion of glycine, L-alanine, L-leucine, L-proline, L-serine, L-lysine, L-asparagine, or L-glutamine) have been synthesized by reaction of [Pd(bipy)Cl2] with an appropriate mono sodium salt of amino acid in water. These complexes have been characterized by chemical analysis and by visible, infrared, and 1H NMR spectroscopy. The detailed 1H NMR and infrared spectral studies of these complexes ascertain the mode of binding of amino acids to palladium through nitrogen of terminal -NH2 group and oxygen of terminal -COO- group. The molar conductance values of these complexes in water suggest them to be 1:1 electrolytes. These complexes have also shown growth inhibition against L1210 lymphoid leukemic, P388 lymphocytic leukemic, Sarcoma 180, and Ehrlich ascitic tumor cells. Some of these complexes show better 50% inhibitory dose values than cis-diamminedichloroplatinum(II).

Effects of transition metals on TRH-receptor interaction

The interaction of TRH receptors and metal ions was investigated. Although the addition of a physiological serum concentration (20 microM) of Zn2+ or Cu2+ to the TRH radioreceptor assay reaction mixture significantly increased the binding capacity, pretreatment of crude synaptic membranes with Ni2+, Zn2+, Cu2+ or Pd2+ resulted in a significant loss of binding activity. The receptor preparation was bound to [3H]TRH in the presence of 10 mM Ni2+ and was solubilized by Triton X-100. Gel filtration was carried out with cold Tris-HCl-Triton buffer without Ni2+. The molecular weight of the solubilized TRH-macromolecular complex was about 300,000 daltons, and Ni2+ was found in the same fraction as the solubilized TRH-receptor. These results suggest that metal ions have inverse effects in different steps of TRH-receptor interaction and that a TRH-receptor molecule indicates a Ni-binding molecule.

Ductility of a dental Ag-Pd-Cu-Au alloy

A silver-palladium type of dental alloy for fixed restorations has been investigated with regard to the ability of the material to be plastically deformed in uniaxial tensile testing after two different age-hardening treatments. A certain degree of ductility is required for the burnishing of the margins. Aged to peak hardness at 350 degrees C after solid-solution annealing at 900 degrees C, the material was found to be brittle owing to a reaction zone along the grain boundaries, promoting an intergranular fracture. When the age-hardening temperature was lowered to 275 degrees C, a less pronounced reaction zone along the grain boundaries could be observed. The accompanying mechanical properties after precipitation hardening at 275 degrees C are probably an acceptable compromise between mechanical strength and ductility. Small particles along grain boundaries and brittleness were also found after solid-solution annealing at 900 degrees C and quenching. It is suggested that the improved ductility after subsequent aging at 275 degrees C is due to a coarsening of these small particles. In the as-cast condition the alloy was softer and more ductile than in the age-hardened state.

Effect of selected six-mercaptopurine metallo-complexes on adenosine deaminase activity in rat tissues

Six-mercaptopurine was compared with its palladium and its bismuth complexes with regard to its effects upon the activity of adenosine deaminase (E.C.3.5.4.4.) in rat tissues. Spectrophotometric and high pressure liquid chromatography analyses were utilized in the determinations of enzyme activity. No effect upon enzyme activity was seen to result from treatment with any of the complexes.

[Biological effects of coordination compounds of transitional metals. The beta-lactamase inhibitory effect of cis-platin, 2-aminopyridine palladium chloride, clavulanic acid and penicillanic acid sulfonate CP 45,899 in the nitrocefin test and Titertek/microtiter automatic system]

The beta-lactamase-inhibiting activity of 6m-ethyl-pyrid-2-yl-ammine palladium-dichloride (Pd 25681) and cis-dichloro-diammine-platinum(II) was studied and compared with the enzyme inhibitory action of potassium clavulanate and the penicillanic acid sulfone CP 45899. Using the nitrocefin test method and the Titertek/Microtiter equipment CP 45899 and potassium clavulanate were the strongest inhibitors of the Bacillus cereus beta-lactamase. Cis-dichloro-diammine-platinum(II) was fourfold less active than the palladium complex PD 25681 in äquimolar concentration. The following ID50 values were found: CP 45899: 0.0281 microgram; K-clavulanate: 0.1274 microgram; Pd 25681: 3.8603 microgram; cis-dichlorodiammine-platinum(II): 12.5120 microgram/100 microliter.

[Comparative study of the mechanism of action of biologically active substances on the membrane-bound mitochondrial monoamine oxidase and Ca2+, Mg2+-dependent ATPase of the sarcoplasmic reticulum]

Mechanism of interaction between biologically active substances and membranes as well as and membrane-bound enzymes of two types: mitochondrial monoamine oxidase (MAO) from rat liver tissue and Ca2+, Mg+2-dependent ATPase from sarcoplasmic reticulum (SR) were studied. All the substances studied inhibited most distinctly the SR ATPase as compared with mitochondrial MAO. EPR technique enabled to detect that BeSO4, aminazine, Pt- and Pd-5-sulpho-8-mercaptoquinolinate affected the membranes of both types decreasing the microviscosity in its hydrophobic part. K2PtCl4 and K2PdCl4 altered the conformation of membrane proteins. All the substances studied were bound by the same amino acid residues of proteins and affected similarly the structure lability of these membranes. As distinct from MAO, interaction of the substances with active sites of ATPase was responsible for pronounced differences in the inhibitory effect of the same substances on various membrane enzymes. Transformation of MAO, accompanied by a decrease in viscosity of hydrophobic part of mitochondrial membrane, contributed to appearance of new enzymatic properties, which appear to occur due to alteration in the protein conformation and to redistribution of the enzyme reactive sites situated relatively close to the membrane surface.

Disodium tetrachloropalladate (Na2PdCl4), an inhibitor of rat liver mitochondrial electron transport

The effects of Na2PdCl4 were studied on isolated rat liver mitochondrial electron transport and oxidative phosphorylation in vitro. Significant reductions in ADP-stimulated respiration were observed with increasing Na2PdCl4 concentrations with both succinate and NADH-linked substrate oxidations. Concentration necessary for half-maximal inhibition of oxygen uptake (EC50) for an NADH-linked substrate system was 18 muM while with succinate as substrate the EC50 was 15 muM. At 64 muM both systems were inhibited maximally at 60 and 80%, respectively. At concentrations of Na2PdCl4 sufficient to inhibit acceptor-stimulated oxygen uptake, there was a concomitant decrease in the rate of ADP phosphorylation as measured by proton absorption. Uncoupling agents had no effect on Na2PdCl4 inhibited mitochondria. Mg-ATPase activity and phosphate acceptor limited (State 4) respiratory activity were not stimulated by any Na2PdCl4 concentration used in these investigations. Data from these experiments indicate that Na2PdCl4 inhibits the mitochondrial respiratory chain in vitro.

[On the biological action of transition metal complexes. 1. The antiviral activity of palladium aminopyridin-complexes (author's transl)]

Some aminopyridine complexes of palladium and PdCl2 showed an antiviral in vitro activity against enveloped DNA and RNA viruses such as vaccinia virus, pseudorabies virus, NDV and FPV. In contrast, naked RNA virus as mengovirus was not affected. The compounds were compatible for chicken embryo as well as FL cells in concentrations of 100-250 microM. The therapeutical index calculated from the maximally tolerated dose and the concentration causing a 50 per cent plaque reduction was determined with more than 45 for vaccinia virus, for example.

[Spectrofluorometric topography of the ATPase center of Ca2+-Mg2+-dependent ATPase of sarcoplasmic reticulum by means of platinum and palladium compounds]

The fluorescence of tryptophan residues in Ca2+--Mg2+-ATPase was studied in the presence of K2PtCl4, K2PdCl4 and 5-sulpho-8-mercaptochinolinate platinum and palladium. It has been shown that both first two compounds quenched the fluorescence dye to bonding with SH-groups in ATPase active centre, but the last two compounds influence the fluorescence by bonding with tryptophan residues. The distance between the SH-groups and tryptophan in the active centre was determined by Foerster--Galanin equation and was equal to 14 +/- 3 A.

[System of pharmacologic control of histamine release by mast cells on exposure to different agents]

A scheme has been devised that makes it possible to assess a specific mechanism of action of any histamine-releasing agent. The scheme suggests a switch off of different stages of histamine secretion--interaction of a histamine liberator with surface cell receptors, entry of Ca2+ into the cell, temperature- and energy-dependent stages of histamine liberation, a stage that depends on microtubules, a system regulating histamine liberation with cyclic nucleotides. The scheme was made use of in clarification of the mechanism of histamine liberation on exposure of the mast cell to a specific antigen, to different doses of heavy metal salts, prednisolone and alkylating cross-binding agents.

Biological activity of metal complexes. I. Interaction of pt(II), pd(II) and rh(I) complexes with E. coli strains and with mice LS fibroblasts in vitro

The effects of a number of Pt(II, Pd(II) and Rh(I) complexes against cultures of Escherichia coli (strains B, H10178, uvra-, recA-) and cultures of mice LS Fibroblasts were tested. Most of the compounds showed higher cytotoxic activity than the cis-Pt(NH3)2Cl2, the compound at present on clinical trial as antittumour drug. A new model of active compound is proposed.

[Mutagenic action of platinum and palladium compounds on bacteria]

Platinum complex compounds are shown to cause mutations in S. typhimurium strains, TA-100 and TA-98 bearing plasmid pKM-101 but not in isogenic strains TA-1535 and TA-1538 lacking the plasmid. The mutagenic action depended on the ligand nature in the complex and did not depend on the extent of the central atom oxidation. No mutagenic activity of the palladium compounds tested was found.

[Interaction of platinum and palladium 5-sulfo-8-mercaptoquinoline complexes with sarcoplasmic reticulum Ca2+-dependent ATPase]

5-Sulfo-8-mercaptoquinoline complexes of platinum and palladium (complexes I and II) effectively inhibit Ca2+-dependent ATPase from sarcoplasmic reticulum. However, in contrast to K2PtCl4, K2PdCl4 and other previously investigated platinum and palladium complexes, they do not interact with the thiol groups of the enzyme. The inhibiting effects of complexes I and II are reversible and competitive with respect to ATP. In aqueous solutions complexes I and II decrease the fluorescence of tryptophane with a simultaneous shift in fluorescence towards the long-wave region. The same effect is exerted by the complexes on the fluorescence of tryptophane residues in Ca2+-dependent ATPase preparations. An addition of tryptophane to the enzyme preparations preincubated with complexes I and II partly restores the enzyme activity. It is assumed that the inhibiting effect of complexes I and II is due to their non-covalent interactions with the trytophane residues vicinal to the ATPase center.

[Effect of platinum and palladium compounds on mitochondrial enzymatic systems]

Effect of platinum and palladium complexes on respiration and ATPase activity in bovine heart tissue as well as on respiration of submitochondrial particles was studied. The highest inhibitory activity was exhibited by the complexes of platinum and palladium with pi-ligands in internal coorhdinational sphere such as ethylene-C H4, norbornadiene-C7H8 and allyl-C3H5. The electron density at the central atom of the complex was not responsible for the inhibitory affect of platinum and palladium on mitochondria.

Platinum and palladium derivatives for chemotherapy studies

Analogues of cis-dichlorodiammineplatinum(II) were prepared in which substituted pyridines (A), 1-(4-aminobenzylidene)indene (B), or DL-3,5,3'5'-tetraoxo-1,2-dipiperazinopropane (ICRF-159) was used in place of ammonia, and in some cases platinum(IV) or palladium(II) was used in place of the platinum(II). Both platinum complexes with ICRF-159 were active against leukemia 1210, but none of the others produced significant life extension following a single ip dose of 400 mg/kg. Attempts to prepare complexes of ICRF-159 with Zn(II), Mn(II), and Cr(III) were unsuccessful, but there were indications of complex formation with CuCl2 and with NiCl2.

Inhibition of creatine kinase activity and alterations in electrophoretic mobility by palladium ions

The toxicological consequences of increased levels of palladium in the environment have not yet been assessed. In this paper, the effect of palladium ions (Pd) on purified rabbit muscle creatine kinase (CPK-MM) and on human serum CPK-MM was examined. When rabbit muscle CPK-MM was treated with Pd, a concentration-dependent inhibition of enzyme activity with a calculated Ki of 0.16 mumol, associated with a marked increase in a electrophoretic mobility of the enzyme toward the anode, was observed. Pd exerted the same effect of human serum CPK-MM, but to a lesser extent. Analysis of binding of Pd to CPK-MM by a colorimetric competitive-binding technique, using chlorpromazine-chromophore, as well as by a dialyzing technique, indicated that the cation may form an extremely strong complex with essential SH groups of the enzyme.

Growth of clinical isolates of anaerobic bacteria on agar media: effects of media composition, storage conditions, and reduction under anaerobic conditions

The quantitative growth, the colony size, and the rate of growth of 47 clinical anaerobic isolates were compared on five different media, namely Brucella agar, brain heart infusion agar, Columbia agar, Schaedler agar, and tryptic soy agar. There was no significant difference in the quantitative growth of the anaerobes inoculated onto the five media. Although no single medium was superior for the growth of all isolates, 12 of 22 isolates, inoculated onto media stored for 4 weeks or less, grew best on Schaedler agar. The effects of supplementation of the media with reducing agents and reduction of the media before use were also analyzed and were found to be affected by the composition and length of storage of the media, as well as the bacteria tested.

[Decreased activity of the palladium catalyst during the processing of vital activity wastes]

The effect of water vapors on the palladium catalyst activity during complete oxidation of organic compounds was studied. The catalyst activity was essentially unaltered when the vapor content in the vapor-gas mixture was below 50 mg/1. The effect of hydrogen sulphide on the palladium catalyst activity during oxidation of organic compounds was investigated. In order to reduce catalyst activity by 80%, 2 mg hydrogen sulphide in the oxidized gas mixture were needed. Catalyst activity was not restored after hydrogen sulphide removal from the gas mixture. It was also demonstrated that the use of a barium-alumovanadium catalyst as a forecontact eliminated the effect of palladium catalyst poisoning and provided a high degree of convesrion during oxidation on this contact.

Effect of 6-mercaptopurine on response to major and minor histocompatibility antigens

Pregraft treatment of chicks with 6 mercaptopurine-palladium complex (6-MP-Pd) resulted in a 16% survival of skin allografts incompatible at the major histocompatibility locus B. These incompatible grafts survived beyond 16 weeks postgrafting and showed profuse feather growth. No form of postgraft treatment was necessary. All nontreated incompatible grafts were rejected prior to 4 weeks postgrafting with no evidence of feather development. The same treatment, however, did not significantly suppress rejection of B-system compatible grafts which differed at minor histocompatibility loci. The rate of feather growth in successful B-system compatible grafts was significantly enhanced by the 6-MP-Pd treatment through 2 weeks postgrafting. Though the drug appears to affect the cellular immune system, the humoral immune response was unaffected as evidenced by a high antibody titer following turkey erythrocyte challenge.

Effects of some inorganic elements on nitrogen-fixation in blue-green algae and some ecological aspects of pollution

Nitrogen-fixation by two species of Nostoc, one of them a lichen phycobiont, was generally stimulated by low concentrations of arsenic, cadmium, nickel, lead, palladium, and zinc. Higher concentrations (0.025 to 0.125 ppm) of arsenic, nickel, and palladium were also stimulatory; however, higher concentrations of cadmium, lead, and zinc tended to inhibit fixation. With the exception of palladium and zinc at low concentrations these six tested elements tended to inhibit nitrogen-fixation in Chlorogloea fritschii and Westiellopsis sp.

[Inhibition of membrane-bound adenosine triphosphatase by platinum and palladium salts]

Inhibition capacity of platinum and palladium complexes is studied on membrane-bound ADTP. The degree of inhibition of the enzyme activity is determined by the nature of the central atom and by the electron density on it, as well as by the ligand donor-acceptor capacity, by its mobility. The configuration of the complex and the charge of complex ion are of importance. The acidoligands studied according to their inhibition effect can be arranged in the following line: NO2, Cl, Br, SCN, I, which is true both for platinum and palladium compounds. For palladium complexes this line coincides with the location of ligands according to their ability to draw off the electron density from the central atom while in case of platinum complexes it has an opposite course of relationship for platinum and palladium complexes, points to a different mechanism of their interaction with the enzyme.

[Interaction of platinum and palladium complexes with thiol groups of Ca2+-dependent ATPase from sarcoplasmic reticulum]

In native preparations of sarcoplasmic reticulum 10-12 thiol groups (in g-eqv per 10(5) g of protein) were estimated by the Benesh method (titration with AgNO3) and 2 thiol groups--by Ellman (titration with dithionitrobenzoic acid). After denaturation of the sarcoplasmic reticulum preparations with 8 M urea 10-12 thiol groups were also determined by the Ellman method. When the preparations were treated with platinum tetrachloride or with palladium diaminodichloride, only 3 thiol groups were estimated by the Benesh and no one - by the Ellman method. Platinum and palladium complexes inhibited also the Ca2+-dependent activity blocking the transport of Ca2+ in sarcoplasmic reticulum. The inhibition was partially removed by glutathione.