(n.) A mineral of a nearly black color and vitreous luster, and consisting principally of the silicates of yttrium, cerium, and iron.
Example Sentences:
Lanthanum
Definition:
(n.) A rare element of the group of the earth metals, allied to aluminium. It occurs in certain rare minerals, as cerite, gadolinite, orthite, etc., and was so named from the difficulty of separating it from cerium, didymium, and other rare elements with which it is usually associated. Atomic weight 138.5. Symbol La.
Example Sentences:
(1) This was apparent by standard flux techniques only in low (65 mM) Na solutions, but was readily discernible in normal Na (125 mM) with the "lanthanum-residual" technique.
(2) Lanthanum nitrate used in this investigations is a valuable marker of the intercellular spaces.
(3) Lanthanum inhibits calcium uptake, protein secretion and K+ efflux induced by carbachol without impairing protein discharge stimulated by norepinephrine through the beta-adrenergic receptor.
(4) At every stage studied, neutralized lanthanum used as an ultrastructural tracer was seen filling the intercellular clefts and junction domains.
(5) The enhancement of lanthanum binding was reduced by both H1 and H2 receptor antagonists.
(6) Lanthanum can be used as a bidirectional inhibitor of micropinocytosis.
(7) Increasing the concentration of lanthanum from 0.1 to 10 mM in both the serosal and mucosal media produced a progressive decrease in tissue calcium retention and calcium transport.
(8) Moreover, lanthanum itself as well as lanthanides other than cerium, e.g., gadolinium and didymium (praseodymium, neodymium), were successfully applied and can be recommended as capture agents for phosphatase cytochemistry.
(9) Measurement of (140)La uptake by the living skin shows that lanthanum moves across the external surface of the skin readily, into and out of a compartment that has a limited capacity and is bounded on its internal side by a barrier impermeable to lanthanum.
(10) The shape regeneration of Ca2+-loaded cells, however, is blocked by lanthanum owing to Ca2+-pump inhibition.
(11) A tight junctional network, which shows some permeability to the lanthanum tracer, is located at the apical end of the cells.
(12) Human spermatozoa incubated in a strontium- or lanthanum-based medium, or T6 + 10% maternal human serum (HS) supplemented with 12 mM 8-bromo cyclic guanosine 3,5'-monophosphate and 10 mM imidazole for a 4-hour period before transfer to fresh T6 + 10% HS for a further 6 hours, demonstrated a significant increase (P less than 0.05) in acrosomal loss compared with T6 + 10% HS for a total 10-hour incubation.
(13) Using lanthanum tracer, we investigated the ultrastructure and the cell membrane permeability of mouse cardiac muscles in the early stage of severe burns.
(14) The lanthanum fluoride electrode activity coefficients.
(15) Only when mitochondria were disrupted did lanthanum gain access to internal sites on mitochondrial membranes.
(16) Moreover, the deposition of abnormal lamellar body contents resulted in the formation of clefts in the intercellular spaces at the stratum granulosum-stratum corneum interface, resulting in increased permeability through these domains shown by lanthanum perfusion.
(17) During either sustained diuresis (five animals) or vasopressin-induced antidiuresis (four animals), individual surface convolutions of distal convoluted tubules or early cortical collecting ducts were preserved for ultrastructural examination by intraluminal microperfusion with a glutaraldehyde-formaldehyde fixative followed by a second microperfusion with a lanthanum tracer.
(18) Lanthanum was rarely observed extravascularly and never extended to the enameloid matrix at the secretion stage.
(19) Perfusion of lanthanum chloride in saline for 15 min, followed by precipitation of lanthanum phosphate during fixation, resulted in lanthanum tracer distribution similar to that of horseradish peroxidase.
(20) The permeability of capillaries was investigated utilizing an in vivo injection of horseradish peroxidase (HRP) and an in situ perfusion of a balanced salt solution containing HRP and lanthanum chloride.