Lanthanum, inhibition

Haksar a, Maudsley DV, Peron EG and Bedigian E (1976) Lanthanum inhibition of ACTH-stimu-lated cyclic AMP and corticosterone synthesis in isolated rat adrenocortical cells. J Cell Biol 68 142-153. 

Van Beeeman C and De Weee P (1970) Lanthanum inhibition of Ca efflux from the squid giant axon. Nature 226 760-761. 

Heart. Lanthanum causes redistribution of Ca ions in cardiac muscle cells, suppressing the zero-sodium response (e.g., a maintained contracture and an asynchronous localized contraction) (Mead and Clusin 1985). Lanthanum also blocks the inward Ca current in guinea pig (Wendt-Gallitelli and Isenberg 1985 Ravens, Steimnann et al. 1987) and bullfrog (Nathan, Kanai et al. 1988) heart muscle cells, thereby blocking contractility. In addition, lanthanum inhibits the ATP-dependent component of Ca -efflux (Brommimdt and Kavaler... 

Rom-Glas, A. Sandler, C. et al. (1992). "The nss mutation or lanthanum inhibits light-induced Ca2+ influx into fly photoreceptors." 7Ge Physiol, 100(5), 767-81. 

High Temperature Corrosion. The rate of oxidation of magnesium adoys increases with time and temperature. Additions of berydium, cerium [7440-45-17, lanthanum [7439-91-0] or yttrium as adoying elements reduce the oxidation rate at elevated temperatures. Sulfur dioxide, ammonium fluoroborate [13826-83-0] as wed as sulfur hexafluoride inhibit oxidation at elevated temperatures. 

Feltz, A. Martin, A. (1987) Solid-state reactivity and mechanisms in oxide systems. 11 Inhibition of zinc ferrite formation in zinc oxide - a-iron(lll) oxide mixtures with a large excess of a-iron(lll) oxide. In Schwab, G.M. (ed.) Reactivity of solids. Elsevier, 2 307—313 Fendorf, S. Fendorf, M. (1996) Sorption mechanisms of lanthanum on oxide minerals. Clays Clay Miner. 44 220-227 Fendorf, S.E. Sparks, D.L. (1996) X-ray absorption fine structure spectroscopy. In Methods of Soil Analysis. Part 3 Chemical Methods. Soil Sd. Soc. Am., 377-416 Fendorf, S.E. Eick, M.J. Grossl, P. Sparks, D.L. (1997) Arsenate and chromate retention mechanisms on goethite. 1. Surface structure. Environ. Sci. Techn. 31 315-320 Fendorf, S.E. Li,V. Gunter, M.E. (1996) Micromorphologies and stabilities of chromiu-m(III) surface precipitates elucidated by scanning force microscopy. Soil Sci. Soc. Am. J. 60 99-106... 

However, the effects of Ca are not seen with all stimuli the production of Of in response to phorbol myristate acetate was unaffected in medium lacking Ca, Lanthanum, which can act as a competitive inhibitor of Ca, reduced the effect of Ca in suspensions of PMNs stimulated with FMLP , That Ca acted by entering the cell was suggested because calcium ions did not affect the binding of FMLP. However, verapamil which blocks the channel for Ca in cell membranes, produced dose-dependent inhibition of the formation of Of and of the influx of Ca. This inhibition could be overcome by increasing the concentration of Ca in the medium . The reasons for the requirement of Ca for activation by some stimuli but not by others might be related to the site at which the stimulus in question acts. PMA, for example, might act at a site beyond the point at which Ca is required. 

The lanthanides find some use as stabilizers for polymers. The coating of polycarbonate with a poly(vinyl alcohol) film containing CeCl3 inhibits photodegradation of the polycarbonate.151 The naphthenates of cerium, lanthanum and yttrium act as thermal stabilizers for polyorgano-siloxanes.152... 

The Ca -ATPase piays an essential role In the pumping of calcium out of cells, and in the control of its cytosolic concentration. In the heart, the role of the pump is minor with respect to that of the sodium-calcium exchanger, but is most probabiy predominant in skeletal and smooth muscle. The pump is encoded by four independent genes, showing different patterns of tissue-specific expression and alternative splicing of the primary transcripts. The intracellular Ca pump proteins from skeletal muscle sarcoplasmic reticulum (SR), cardiac SR and brain microsomes are similar. Thapsigargin is a potent inhibitor, also lanthanum salts inhibit the pump at most sites. 

Before activity measurements, the different catalysts were either dechlorinated at 500°C for 10 h in a stream of N2 + 10 % H2O or thermally aged at 900°C for 16 h in a stream of 1 % O2, 10 % H2O, 10 % CO2, N2, and then reduced at 500°C. The dechlorination treatment was carried out in order to avoid the inhibiting effect of chlorine on the activity of metals for oxidation reactions (2). The chlorine content of dechlorinated samples was below 0.2 wt %. Metal and lanthanum oxide loadings of the various catalysts are reported in Table 1. 

Cerium-, copper-cerium coexchanged ZSM-5, copper-MCM-22, copper- and cerium-EMT type zeolite, copper-FAU type zeolite and copper-Beta exhibit an activity of the same order as that of copper-ZSM-5 in NOx reduction under simulated Diesel exhaust conditions. Propene was used as the reducing agent. The catalysts were used in a powder form and their activities tested in a fixed-bed flow reactor at a space velocity of 50 000 H . Copper-SAPO-34 and cerium- and gallium-EMT type zeolite have a moderate activity under the same conditions. The presence of water vapor inhibits the activity of EMT-zeolites. When an ageing procedure is carried out on copper-EMT type zeolite, dealumination occurs. The increase of the Si/Al ratio of the zeolite does not limit the dealumination process. The exchange of the zeolite with lanthanum prevents the zeolite from dealumination but leads to a loss of the catalytic activity. 

Calcium binding was assayed by ultrafiltration and was found to exhibit a />H optimum at about 7.4. One class of binding sites is present which bind one mole of calcium per mole of protein with a dissociation constant equal to 2.5 X 10 5M. Calcium binding was competitively inhibited by other divalent cations the binding affinity being Ca++, Mn++, Sr++, Ba++, Mg++ (160). Lanthanum salts irreversibly precipitate brain CBP-II. Those cations which are the most effective inhibitors of calcium binding to this protein are also the most active for in vitro calcium-dependent release of neurotransmitters. 

The inhibiting effect of thorium is substantial, since the transformation ratio is only 1,5 % after 45 hours at 1105°C and 4,5 % after 160 hours. In the case of lanthanum, it is still more significant since no alpha Al O was detected after 45 hours and only 1.5 % after 150 hours. ... 

Lanthanum carbonate is a phosphate binder that inhibits gastrointestinal (Gl) absorption of phosphate by forming highly insoluble lanthanum phosphate complex with dietary phosphate released from food during digestion. It is indicated for reducing serum phosphate in patients with end-stage renal disease. 

Naylor WG and Harris JP (1976) Inhibition by lanthanum of the Na K activated, ouabain-sensitive adenosine triphosphatase enzyme. J Mol Cell Cardiol 8 811-822. 

Reed KC and Bygeave FL (1974b) The inhibition of mitochondrial calcium transport by lanthanides and ruthenium red. Biochem J 140 143-155. Sabbioni F, Nicoiaou GR, Peitea R, Beccaloni F, Coni F, Alimonti A and Caeoli S (1990) Inductively coupled atomic emission spectrometry and neutron activation analysis for the determination of clement reference values in human lung tissue. Biol Trace Flem Res 26-27 757-768. Sanborn WG and Langee GA (1970) Specific uncoupling of excitation and concentration in mammalian cardiac tissue by lanthanum. J Gen Physiol 56 191-217. 

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