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The GPLA B and Ia (I region-associated) antigens are the products of genes found in the guinea pig major histocompatibility complex. Because of their importance in immune response phenomena, a structural study of these antigens was undertaken. [3H]leucine and [3H]fucose were internally incorporated into guinea pig lymph node cells. The GPLA B and Ia antigens were solubilized by the nonionic detergent Nonidet P-40, purified by affinity chromatography using an adsorbent column of lentil lectin, isolated by immunoprecipitation, and examined by discontinuous polyacrylamide-sodium dodecyl sulfate gel electrophoresis. The GPLA antigens B.1, B.2, B.3, and B.4, were shown to be glycoproteins of mol wt 40,000 daltons and to be noncovalently associated with a 12,000 dalton protein. The molecules bearing B.2 and B.3 in a B.2/B.3 heterozygote are shown to be separable, suggesting the antigenic determinant is a primary gene product. In addition, a new GPLA determinant, S, which resembles the B antigen in that it is found on a molecule of approximately 40,000 daltons, was studied. In a B.2/B.3 S+ animal the molecule bearing antigen S was shown to be independent of those bearing B.2 and B.3, providing evidence that the genes determining B and S are at separate loci. The Ia-bearing molecules identified by anti-Ia.2,4 are glycoproteins of mol wt 58,000 daltons which are composed of two subunits of 33,000 and 25,000 daltons, respectively, linked by disulfide bonds. The Ia-bearing molecules are independent of GPLA-bearing molecules, indicating different loci determining these antigens. By all criteria, the guinea pig GPLA B antigens appear homologous to the murine H-2D and H-2K antigens, while the guinea pig Ia antigens appear homologous to the Ia antigens of the mouse.

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Cognitive and extrapyramidal effects of cholinomimetic therapy were evaluated in 8 patients with progressive supranuclear palsy. Each was randomized to a 10-day double-blind crossover trial of physostigmine and placebo. Physostigmine treatment was associated with marginal and inconsistent changes in long-term memory, suggesting that cholinergic therapy alone is insufficient to restore cognitive function. Motor scores remained unchanged.

The application of the third Universal 2012 definition of MI instead of the Universal 2007 definition resulted in a 1% reduction of the total number of MIs. For a practical clinical purpose, the reduction was confined to patients with Type 4a MI. The change of definition had no impact on all-cause mortality.

The mechanisms by which thymus-derived (T) lymphocytes exert their influence to control the immune response to thymus-dependent antigens have been the subject of recent intense study. Attention has been concentrated on situations in which the immune response is regulated by Ir genes located within the I-region of the major histocompatibility complex. The discovery of I-region associated (Ia) alloantigens, encoded by genes closely linked to or identical with the Ir genes (1, 2), raised the possibilities that the Ia antigens were on the surface of T lymphocytes and that they were intimately involved in the mechanisms controlling the immune response. A variety of functional studies have supported these possibilities. Schwartz et al. demonstrated that genetically controlled proliferation of T cells induced by antigens in vitro could be inhibited by anti-Ia antisera (3). Munro and Taussig (4) and Takemori and Tada (5) have described T cell factors that react with anti-Ia antisera and exert either helper or suppressor activity on other cells. However, serological studies attempting to directly demonstrate Ia antigens on T cells have yielded contradictory results. Several initial studies suggested that thymocytesT and peripheral T cells could not react with anti-Ia antisera (6-9), while others indicated that Ia antigens were present on T cells (1, 2, 10-12).Abbreviations: T, thymus-derived; B, bone-marrow-derived; FACS, fluorescence-activated cell sorter; Ia, immune-response-region-associated; Ig, immunoglobulin; PBS-BSA-azide, phosphate-buffered saline containing 2% bovine serum albumin and 0.02% sodium azide; RAMB, rabbit antiserum to mouse brain; NaDodSO4, sodium dodecyl sulfate; NMS, normal mouse serum. t

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