The effect of calcium and selected calcium antagonists on the lung phospholipid secretion associated with lung distension was examined in newborn rabbits. Lung distension was produced by saline lavage or air inflation in freshly killed pups. Calcium or calcium antagonists were added to the lavage solution. The fractional stimulation of secretion with 1.0 mM calcium was 1.94 +/- 0.28 (p less than 0.01), but ethylene diamine tetraacetic acid (EDTA) did not have the expected inhibitory effect. There was dose-related inhibition of phospholipid secretion induced by the calcium antagonist, lanthanum, the fractional recovery decreasing from 1.0 +/- 0.23 at 10(-5) molar, to 0.43 +/- 0.19 at 0.5 x 10(-4) molar, to 0.22 +/- 0.03 at 10(-4) molar and 0.19 +/- 0.05 at 10(-3) molar (p less than 0.001). This inhibition was significantly reversed by the addition of 10 mM calcium. Although nifedipine and verapamil had no effect, nickel and cadmium also inhibited secretion. Therefore, it is likely that lanthanum acted as a calcium channel blocker, suggesting the importance of extracellular calcium. The observation that intense calcium chelation with ethylene glycol bis-aminoethylether tetraacetic acid-bis-aminophenoxyethane tetraacetic acid (EGTA-BAPTA) had a significant inhibitory effect, supports the conclusion that a superficial calcium pool in the plasma membrane may be an important stimulus for phospholipid secretion during lung distension. The inhibitory effect of neomycin, a drug known to displace superficial calcium, was consistent with this conclusion.

Animals↗

PubMed1976

Teratology and percutaneous toxicity studies on hair dyes.

Twelve hair dye formulations were tested for systemic toxicity by topical application twice weekly for 13 wk to groups of 12 New Zealand white rabbits and for teratologic effects following applications to groups of 20 pregnant Charles River CD rats on days 1, 4, 7, 10, 13, 16, and 19 of gestation. The three semipermanent formulations were applied as is, and the nine oxidation dyes were mixed 1:1 with 6% hydrogen peroxide just prior to application, as in normal use. The formulations induced a broad spectrum of dyes and dye intermediates used or considered useful in oxidative and semipermanent hair color products. In the teratology study no biologically significant soft tissue or skeletal changes were noted. Similarly, the mean numbers of corpora lutea, implantation sites, live fetuses, and resorptions per pregnancy, as well as numbers of litters with resporptions, were not significantly affected by the dye treatment. In the percutaneous toxicity study there was no evidence of compound-induced systemic effects. Microscopic examination of 25 tissues from each animal gave no indication of histomorphologic evidence of toxicity. No dye discoloration of urine was seen at any time during the test or at necropsy. Some of the dye groups showed epidermal hyperplasia, which was probably a reflection of slight irritation due to the frequency of application of the oxidation formulations.

Abnormalities, Drug-Induced↗

PubMed1966

[Preparative separation of hemoglobin and myoglobin on sephadex and epidex gels].

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Chromatography, Gel↗

PubMedDate not supplied

Lessons from cat virus.

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AIDS Vaccines↗

PubMedDate not supplied

AIDS and human rights.

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Acquired Immunodeficiency Syndrome↗