Enchancement of the antiplaque value of antibacterial agents by enamel-conditioning methods. I. Rationale, mechanism, and initial findings

A method is proposed to induce chemically the incorporation of bacterial agents inot enamel and thus rende this tissue resistant to bacterial colonization. It consists of promoting a slight initial dissolution of enamel, followed immediately by tis reprecipitation. During this latter phase, antibacterial agents included in the test formulations would become trapped in the reprecipitating enamel. That this happens is proved by the chemical detection of antibacterial agents in treated enamel, as well as by the development of a remarkable resistance of treated specimens to grow in vitro plaque.

Deep-Sea pH

In the northeastern Pacific Ocean, north of 22 degrees N and east of 180 degrees W, a deep-sea pH maximum of 7.9 exists near 4000 meters. The effect of hydrostatic pressure on the dissociation constants of carbonic acid in sea water appears to be important in its formation.

Electrolytic Conductance of Sea Water: Effect of Calcium Carbonate Dissolution

Calcium carbonate dissolution in the presence of excess carbon dioxide increased the specific conductance of sea water by approximately 6 x 10(-5) ohm(-1)cm(-1) per millimole of carbonate dissolved. The observed conductance increase can be explained by the partial equivalent conductance of calcium bicarbonate and by the hindrance effect of uncharged carbon dioxide dissolved in sea water.

Amino Acids in Deep-Sea Water

Approximately 17 different amino acids in acid hydrolyzates of dissolved organic material in sea water to depths of 3500 meters from the central Gulf of Mexico have been identified by ion-exchange resin chromatography. They are glutamic acid, lysine, glycine, aspartic acid, serine, alanine, leucine, valine plus cystine, isoleucine, ornithine, methionine sulfoxide, threonine, tyrosine and phenylalanine, histidine, arginine, proline, and methionine. The results indicate that the dissolved organic material in deep-sea water may make an important contribution to the organic budget of the sea.