Myofibrillar ATPase, DNA and hydroxyproline content of human hypertrophied heart.

70 human hearts were studied less than 36 hours after death. The apex, and in some cases other parts of the myocardium were homogenized, DNA, hydroxyproline content, myofibrillar Ca2+ and Mg2+ ATPase were measured. In normal hearts the DNA and collagen content were 372 +/- 9 mg and 36 +/- 7 mg.

[Histoenzymologic study of anticholinesterase activity of ciguatoxic extracts of Ceochetus striatus (Gunther) and Plectrompus leopardus].

The use of histo-enzymological techniques for visualizing the cholinesterasic spots on the motory plate is turned to account by the authors to point out the inhibition of the cholinesterasic processes, by some fractions of the ciguatoxins at the level of the neuro-mucular synapsis. The results obtained confirm, on one hand, the efficiency of the method to test the anti-cholinesterasic activity of some fractions of the ciguateric extracts, and, on the other hand, enable the establishment of the fact that even clinically non toxic individuals from fishspecies, dwelling in tropical coral biotops, can provoke a slightly marked but real inhibition of the cholinesterases, provided the contact between the fish extract and the neuro-motory plate is long enough in time. This observation reinforces the thesis of the ecological origin of the toxins along the alimentary chain of the reef biocoenosis.

[Ciguatera: neurophysiological demonstration of toxicity of several ciquatoxic fractions].

Raw extracts from one Polynesian, frequently ciguatera-inducing fish were submitted to fractional distillation by means of a chromatographic process using a silicic acid column. Three out of the seven fractions split this way exhibited either anticholinesterasic properties, or directly toxic properties at the muscle-cell level: fraction 5, which is not antagonized by atropine, presumably accounts for this direct action, as it competes with calcium at membrane sites. Fraction 6 appears to be more specially responsible for the anticholinesterasic action.