(n.) A common mineral embracing many varieties varying in color and in composition. It occurs in monoclinic crystals; also massive, generally with fibrous or columnar structure. The color varies from white to gray, green, brown, and black. It is a silicate of magnesium and calcium, with usually aluminium and iron. Some common varieties are tremolite, actinolite, asbestus, edenite, hornblende (the last name being also used as a general term for the whole species). Amphibole is a constituent of many crystalline rocks, as syenite, diorite, most varieties of trachyte, etc. See Hornblende.
Example Sentences:
(1) Three subcohorts were defined: 3212 men whose only exposure to asbestos was to amosite; 3430 exposed to crocidolite; and 675 to both amphiboles.
(2) Amphibole fibre counts were raised when compared with a non-occupationally exposed group and matched those seen in cases of pleural plaques, mild asbestosis, and mesothelioma.
(3) The second, with amphibole or glassy fibres, is mediated by fibronectin which first binds to the fibre.
(4) Six measures of asbestos-in-air concentration were considered: (1) total asbestos structures per cubic centimeter: (2) chrysotile structures per cubic centimeter; (3) amphibole structures per cubic centimeter; (4) structures per cubic centimeter at least 0.5 micron long and at least five times wide; (5) structures per cubic centimeter at least 5 microns long; and (6) structures per cubic centimeter at least 5 microns long and at least 0.2 micron wide.
(5) The ingestion of filtered water results in the eventual disappearance of amphibole fibers from urine.
(6) When fibre-length distributions were calculated using a scanning electron microscope, however, it was found that the chrysotile clouds used in this study contained many more fibres over 20 microgram long than either of the amphibole clouds.
(7) A suitable quarry was found about 11 km from the port but unfortunately the rock was found to be contaminated to a small extent with a fibrous mineral identified with the analytical transmission electron microscope as a non-commercial type of fine amphibole with many long fibres.
(8) The most positive lavages, probably reflecting exposure to industrial amphiboles, were found in patients presenting with radiological evidence of asbestosis.
(9) The amphibolic asbestos types lie in the upper half and the rock wool sample in the lower half of the range.
(10) Based on the results obtained, the following metabolic pathway is proposed: isopropylbenzene----2,3-dihydro -2,3-dihydroxyisopropylbenzene----3-isopropylcatechol----2 -hydroxy-6-oxo-7-methylocta-2,4-dienoate----isobutyrate + 2-oxopent-4-enoate----amphibolic intermediates.
(11) While amphibole cleavage fragments are usually visible by PCM, asbestos fibers (such as amosite and chrysotile) have finer widths that may render them invisible by PCM.
(12) In general, chrysotile had a toxic effect on the macrophages, whereas amphibole varieties did not.
(13) Of particular importance is an apparent increase in the proportion of mesothelioma risk attributable to tremolite, since the fibers heretofore most responsible for that disease--commercial amphiboles--have been or are being severely regulated or completely eliminated in production and use.
(14) The first reported case was a village woman whose lung tissue contained amphibole asbestos fibres, which were later identified as tremolite.
(15) Crocidolite fiber, a commercial amphibole not native to the region, was nonetheless identified in lung tissue from 15 of 23 chrysotile miners and millers.
(16) There was a rather good correlation between numbers of amphibole fibers and asbestos bodies, with an average ratio of 10:1.
(17) Chrysotile asbestos was much more active in binding IgG than was amphibole asbestos.
(18) Analytical electron microscopy of asbestos body cores showed that in the BL group 95.6% were chrysotile fibres whereas in the AC group amphiboles accounted for 93.1%.
(19) The magnesium amphibole contained the longest (6.03 microns) fibres, and the nickel amphibole contained the shortest (2.7 microns) fibres, resembling those of crocidolite.
(20) Electron microscopic examination of these water samples confirms the presence of asbestiform amphibole fibers.
Calcium
Definition:
(n.) An elementary substance; a metal which combined with oxygen forms lime. It is of a pale yellow color, tenacious, and malleable. It is a member of the alkaline earth group of elements. Atomic weight 40. Symbol Ca.
Example Sentences:
(1) In studies of calcium metabolism in 13 unselected patients with untreated sarcoidosis all were normocalcaemic but five had hypercalcuria.
(2) After stimulation with lipopolysaccharide and calcium ionophore A23187, culture supernatants of clones c18A and c29A showed cytotoxic activity against human melanoma A375 Met-Mix and other cell lines which were resistant to the tumor necrosis factor, lymphotoxin and interleukin 1.
(3) The half-life of 45Ca in the various calcium fractions of both types of bone was 72 hours in both the control and malnourished groups except the calcium complex portion of the long bone of the control group, which was about 100 hours.
(4) Calcium alginate dressings have been used in the treatment of pressure ulcers and leg ulcers.
(5) of PLA2 caused marked degranulation of mast cells in the rat mesentery which was facilitated by addition of calcium ion (10 mM) but antagonized by pretreating with three antiinflammatory agents.
(6) Thus adrenaline, via pre- and post-junctional adrenoceptors, may contribute to enhanced vascular smooth muscle contraction, which most likely is sensitized by the elevated intracellular calcium concentration.
(7) It includes preincubation of diluted plasma with ellagic acid and phospholipids and a starting reagent that contains calcium and a chromogenic peptide substrate for thrombin, Tos-Gly-Pro-Arg-pNA.
(8) The results show that endolymph is extremely inhomogenous with respect to calcium potentials.
(9) The occupation of the high affinity calcium binding site by Ca(II) and Mn(II) does not influence the Cu(II) binding process, suggesting that there is no direct interaction between this site and the Cu(II) binding sites.
(10) This was unlike the action of the calcium channel blocker, cadmium, which reduced the calcium action potential and the a.h.p.
(11) Increases in extracellular calcium antagonized the negative inotropic effect.
(12) Plasma membranes were isolated from rat kidney and their transport properties for sodium, calcium, protons, phosphate, glucose, lactate, and phenylalanine were investigated.
(13) In experiments performed to determine whether PtdIns(4,5)P2 hydrolysis induced by TRH may have been caused by the elevation of [Ca2+]i, the following results were obtained: the effect of TRH to decrease the level of PtdIns(4,5)P2 was not reproduced by the calcium ionophore A23187 or by membrane depolarization with 50 mM K+; the calcium antagonist TMB-8 did not inhibit the TRH-induced decrease in PtdIns(4,5)P2; and, most importantly, inhibition by EGTA of the elevation of [Ca2+]i did not inhibit the TRH-induced decrease in PtdIns(4,5)P2.
(14) The distribution of gelsolin, a calcium-dependent actin-severing and capping protein, in the retina of the developing and adult rabbit was studied.
(15) In K+-depolarized basilar arteries, ifenprodil competitively antagonized the response to Ca2+, and this was enhanced by pre-incubation in calcium hopantenate.
(16) Thirty of the 32 women of the calcitonin group and 27 of 28 women of the calcium group finished treatment.
(17) The influence of calcium ions on the electrophoretic properties of phospholipid stabilized emulsions containing various quantities of the sodium salts of oleic acid (SO), phosphatidic acid (SPA), phosphatidylinositol (SPI), and phosphatidylserine (SPS) was examined.
(18) Hypercalcitoninemia was the most pronounced in patients with cardiac rhythm disorders and a simultaneous reduction in total serum calcium.
(19) The effects of low doses of dihydropyridine (DHP) calcium channel antagonists nimodipine, nifedipine, (-)-R-202-791, and amlodipine, the DHP calcium channel agonist BAY K 8644 were investigated on clonic convulsions to pentylenetetrazole (PTZ) in mice.
(20) A comprehensive review of the roentgenographic features of calcium pyrophosphate crystal deposition disease (pseudogout) is presented.