We have explored the processes regulating presynaptic calcium concentration ([Ca(2+)](i)) in the generation of post-tetanic potentiation (PTP) at crayfish neuromuscular junctions, using spectrophotometric dyes to measure changes in [Ca(2+)](i) and [Na(+)](i) and effects of inhibitors of Ca(2+)-transport processes. The mitochondrial Na(+)/Ca(2+) exchange inhibitor CGP 37157 was without effect, w...

Since monosodium urate (NaU) may play an important etiologic role in the formation of renal stones containing Ca in patients with hyperuricosuria, the current studies were undertaken to define some of the physiocochemical factors which determine the formation of NaU. In solutions containing Na, uric acid was rapidly transformed to NaU at pH greater than 6. The results indicated that NaU, and no...

Na, K and Cl measurements have been made on frozen sections of chick red blood cells throughout embryonic development, using electron-probe microanalysis. There is an apparent fluctuation in the levels of these elements during maturation, although the Na/K ratio remains fairly constant. The nuclear Na concentration resembles that of the cytoplasm, rather than that of the medium, at all stages. ...

The removal of CO2 through chemical absorption in a bench-scale spray dryer absorber was investigated experimentally using the lime slurry as absorbent. The effect of important operating parameters on CO2 removal efficiency has been investigated; in selected ranges of operating parameters, increasing gas inlet temperature and absorbent concentration lead to permanent efficiency decline, increas...

Two recent studies reported that Na-Ca exchange in the outer segments of tiger salamander rod photoreceptors (Cervetto, L., Lagnado, L., Perry, R. J., Robinson, D. W., and McNaughton, P. A. (1989) Nature 337, 740-743) and of bovine rod photoreceptors (Schnetkamp, P. P. M., Basu, D. K., and Szerencsei, R. T. (1989) Am. J. Physiol. 257, C153-157) requires and transports K+ in a 4Na/(1Ca+1K) stoic...

This paper reports a study on mice and human to check the theory of Stolkowski which hypothesizes that mineral (Na, K, Ca) imbalance in the diet of the female before fertilization affects the sex ratio of the progeny. For this aim, total 40 female and 16 male 2 months age white mice used; which were separated into 8 groups, each of them consisted of 5 female and 2 male animals. Group 1 was a co...

In many nonexcitable cells, hormones and neurotransmitters activate Na(+) influx and mobilize Ca(2+) from intracellular stores. The stores are replenished by Ca(2+) influx via "store-operated" Ca(2+) channels (SOC). The main routes of Na(+) entry in these cells are unresolved, and no role for Na(+) in signaling has been recognized. We demonstrate that the SOC are a major Na(+) entry route in ar...

The data obtained from field and geothermometric studies and also the REE composition of fluorites associated with lead mineralization at the Kamar-Mehdi mine are compatible with a structurally controlled, fissure filling, epigenetic, hydrothermal origin. Homogenization and last ice melting temperatures for primary fluid inclusions trapped in fluorite crystals indicate that the mineralizati...

Dear Sir: With ion-selective microelectrodes, it is possible to measure intracellular ion activities and calculate transmembrane electrochemical potential differences. Recently, these techniques have been carefully applied to the measurement of Na and Ca ion activities in mammalian ventricular and Purkinje fibers (Sheu and Fozzard, 1982). The results show that under a wide variety of circumstan...