Increased plasma catecholamines in high renin hypertension.

Plasma catecholamines, indexes of sympathetic nervous tonicity, were measured simultaneously with renin both supine and after standing plus furosemide in patients with primary hypertension and normotensive volunteers. Seventy percent of hypertensive patients with high renin levels had increased catecholamines compared with a 14% incidence in the combined group with low and normal renin (P less than 0.001). Basal catecholamines were related directly to renin in the hypertensive patients and to blood pressure in the normal (P less than 0.05), but not in the high and low renin subgroups, and inversely to percent increase of catecholamines after standing plus furosemide in hypertensive and normotensive patients (P less than 0.01). Sympathetic nervous hypertonicity may be responsible for the elevation of blood pressure and for the activation of the renin-angiotensin system in patients with high renin hypertension.

Antigenicity and immunogenicity of synthetic peptides of foot-and-mouth disease virus.

Peptides reactive with two neutralizing monoclonal antibodies raised against intact foot-and-mouth disease virus A10 were identified with the aid of all overlapping (hexa)peptides of the outer structural viral protein VP1 and located on the viral surface. Using this procedure, it was possible to define those amino acids within a peptide which were critical in the binding of antibody to that peptide. One eight amino acid long peptide, containing six such amino acids, was virtually indistinguishable from viral antigen in its ability to bind monoclonal antibody as determined by competition tests. Another peptide, which was able to induce neutralizing activity as well, showed no competition and possessed fewer amino acids contributing to binding. This peptide appeared to be an incomplete epitope. Comparison of our data with those of others suggests that this may apply commonly to the reactive peptides described.