Herbert E. Longenecker

Centruroides sculpturatus venom and platelet reactivity: possible role in scorpion venominduced defibrination syndrome

Abstract The effect of Centruroides sculpturatus venom and some purified fractions on the aggregation behavior of dog platelets has been examined. The venom causes a sustained partial aggregation, which proceeds almost instantly to complete aggregation on addition of adenosine diphosphate (ADP): the maximum aggregation to ADP is unaffected. The effects of the venom are not mimicked by any of the currently isolated neurotoxins, but are by a fraction obtained from the primary gradient separation of the venom. The effect of the venom is heat labile and unaffected by prior treatment of the platelets with tetrodotoxin, tetraethylammonium or aspirin. Heat lability rules out effects from most inorganic salts, serotonin or phospholipase A 2 , which are heat stable. A defibrination syndrome has been noted following envenomation by a member of the family Buthidae, and possibly occurs for C. sculpturatus venom as well: the effects of the venom on platelets may account in part for the occurrence of this syndrome.

Brain resistance to protein loss on restricted protein intake in weanling rats

Abstract A multi-disciplinary study involving anatomy, pharmacology, biochemistry, and computer sciences was carried out to determine the effect of protein deprivation on the free amino acid levels in the brain of rats who were protein deprived in the weanling stage. The literature has many references to studies of protein and other dietary deprivation in the dam prior to and during pregnancy and also in the preweanling. Few references are available about protein deprivation effects on the weanling rat. Once the species has reached a stage of neural development where the essential elements for higher function are in place, what happens then to the brain and its function during dietary deprivation, particularly protein? If there is any great change, how are the neurotransmitters, which have been identified, affected? In this experiment, the first of a series, an attempt is made to first identify what changes may occur. Specific patterns of change, especially of the neurotransmitters, were followed in the brain as a whole and in three subdivisions, fore-, mid-, and hind-brain. The results of the biochemical assay indicate that once the brain has reached a stage of relative maturity there is an inherent ability of that organ to resist great and obvious changes through some, as yet unknown, mechanism. It would also suggest that studies of protein deprivation beyond the term of this study are in order, for the overt behavior of the deprived animals was not so greatly different from that of the non-deprived. Also, in terms of behavior, it is interesting to note that the total food intake was directly proportional to the amount of protein in the diet, i.e., the less protein in the diet, the less total food intake or conversely, the more protein in the diet, the more the total intake.