No abstract

Summary Unusual combinations—unexpected sets, excess or lack—of antigenic determinants, or Gm allotypes, on the constant regions of the heavy chains of the human IgG1 and IgG3 immunoglobulins are accounted for in terms of genetic events (exchanges, duplications and deletions) involving the DNA sequences, or exons, coding for the three CH1‐, CH2‐ and CH3 domains of the γ1 and γ3 chains. Equal and unequal cross‐overs at the level of the introns without damage to the CH exons are postulated.

A total of 315 normal, unrelated individuals from six of the seven principal religious communities of Lebanon have been typed for 26 alleles of the A and B loci. The gene, haplotype frequencies and Δ values have been calculated. The HLA gene frequencies for loci A and B reported in this study are shown to cross Moslim— Christian lines, but generate a distinguishably different profile for the Armenian immigrant subpopulation. This first‐level homogeneity which is inconsistent with results earlier reported for ABO, rhesus and Gm systems, seems to disappear when linkage disequilibrium deltas are compared.

Bf and C3 type determinations have been performed in a population from Tunisia. The corresponding allele frequencies are as follows: Bfs^S = 0.6173, Bf^F = 0.2813, Bf^S0.7 = 0.0827, Bf^F1 = 0.0187 and C3^S = 0.8326, C3^F = 0.1524, C3^S0.4 = 0.0086, C3‘^{F rare}’ = 0.0064. According to these values, the Tunisian population seems to be situated between Caucasoid and Negroid populations.

Rabbit gastric secretion has the physiological peculiarity of being continuous and uninfluenced by food intake. In this respect, ultrastructural analysis of rabbit parietal cells has revealed morphofunctional features situated between states of rest and very active acid secretion. Our cytochemical study shows that Mg2+ ATPase and ADPase activities vary from cell to cell and can even be totally absent. These activities concern either microcanaliculi or laterobasal folds or both, but never tubulovesicles. Application of the technique of Mayahara to K+ pNPP, associated or not with inhibitors (ouabain, vanadate, N-ethyl-maleimide, sodium fluoride), enabled us to confirm the coexistence of H+, K+, ATPase and Na+, K+, ATPase activities in the rabbit and to determine that these activities concern basolateral folds, microcanaliculi, hyaloplasm and tubulovesicles. The global activity of K+, pNPPase varied considerably in intensity. The results of using inhibitors suggest that proton transport ceases completely in certain cells. The signs of functional alternation found in this study are in agreement with physiological data relative to this animal.