[Systems for regulating the level of Ca2+, cyclic nucleotides, and reverse absorption of neurotransmitters in isolated nerve endings of the rat brain during development of myocardial infarct]. / Systemy reguliatsii urovnia Ca2+, tsiklicheskikh nukleotidov i obratnoe pogloshchenie neirotransmitterov v izolirovannykh nervnykh okanchaniiakh kory golovnogo mozga krys v usloviiakh razvitiia infarkta miokarda.

The systems regulating the levels of Ca(2+)-Mg2+, Ca(2+)-ATPase and potential-dependent absorption of Ca2+ as well as content of cyclic nucleotides, beta-adrenoreceptors, activities of adenylate-, guanylate cyclases and phosphodiesterase were studied in the synaptosomes of rat brain cortex in evolving myocardial infarction. In addition, reverse absorption of noradrenaline, dopamine and serotonin was studied. In one of the animal groups myocardial infarction was simulated after stress. The myocardial infarction, affecting the systems of Ca2+ regulation, caused an increase in reverse absorption of dopamine and serotonin simultaneously with accumulation of lactate in the synaptosomes. In myocardial infarction developed after stress adenylate cyclase was activated, reverse absorption of dopamine was decreased and the content of lactate tended to decrease as compared with the infarction formed without stress effects.

An immunocytochemical study of the proliferating cell nuclear matrix antigen p125/6.5 during rat spermatogenesis.

In previous studies of proliferating mammalian cells a p125/6.5 nuclear matrix antigen displaying a marked increase in mitotic cells has been identified. This antigen was investigated by immunocytochemistry of cryosections of testes at different stages of postnatal development: newborn, 20 days after birth and sexually mature rats. In Sertoli cells, the distribution of the p125/6.5 antigen parallels [3H]thymidine incorporation: present in newborn and absent in sexually mature testes. The p125/6.5 antigen is present also in some prespermatogonia of the newborn rat testis, which do not incorporate [3H]thymidine. At later stages of development, the p125/6.5 antigen is present also in first meiotic prophase spermatocytes displaying an extrachromosomal nucleoplasmic distribution, while absent in spermatids and spermatozoa. These results show that the p125/6.5 antigen increases not only during mitosis, but also during meiosis. They suggest further that this antigen is characteristic of both proliferating cells and cells (prespermatogonia) committed to proliferation.

Formation of single-stranded regions in the course of digestion of DNA with DNAase II and micrococcal nuclease.

In the course of digestion of DNA with DNAase II or micrococcal nuclease, considerable amounts of single-stranded (ss) regions are formed, as determined by a second digestion with ss-specific nucleases, hyperchromicity measurements, and electron microscopy. Most of the ss stretches are located internally in the DNA molecules. The effect appears to be related to regions of decreased stability arising around single-stranded cuts in the double helix.