PURPOSE To determine the stoichiometry of Na+,K+,Cl- cotransport in fetal human nonpigmented ciliary epithelial cells and the effect of forskolin, an adenylyl cyclase activator, on Na+,K+,Cl- cotransport. METHODS 86Rb+ as a marker for K+ was used to study ouabain-insensitive, bumetanide-sensitive 86Rb+ uptake in cultured human nonpigmented epithelial (NPE) monolayers. RESULTS The dependence...

Energy-dispersive X-ray microanalysis was applied on human intraoperative biopsy materials of different thyroid tumors. To ensure suitability of these tissue pieces for quantitative microanalysis in freeze-fractured, freeze-dried bulk specimens, sampling was carried out with strictly defined criteria. Benign adenomas and differentiated and anaplastic carcinomas were selected for the studies on ...

Using radio-tracers, we measured Na(+) and K(+) accumulation in roots and transport to shoots in Zea mays (cv Pioneer 3906) as a function of NaCl concentration and O(2) partial pressure in the nutrient solution. Under fully aerobic conditions, roots partially excluded Na(+) from the shoots over a wide range of NaCl concentration (0.2-200 millimolar). With root anoxia, the exclusion mechanism br...

In this study, we analyzed the correlation of sodium(Na), potassium(K) and calcium(Ca) amounts with spot urine(SU) and 24-hour urine(24-HU) collected as 8-hour portions. 21 hypertensive patients and 21 normotensive individuals were enrolled in the study. Na, K and Ca were studied in three sequential 8-hour urine samples and with the sum of three, 24-HU samples of the cases. Sodium/creatinine, p...

abstract salinity tolerance is one of the major factor influencing crop productivity in arid and semi-arid areas. the salinity tolerance of fruit trees can be enhanced through the use of tolerant rootstocks. this experiment was conducted to investigate the effects of salinity stress and rootstock on the growth, photosynthetic rate and nutrient concentrations of almond (prunus dulcis miller.) cv...

Salinity tolerance in rice, like in other glycophytes, is a function of cellular ion homeostasis. The large divergence in ion homeostasis between the salt-tolerant FL478 and salt-sensitive IR29 rice varieties can be exploited to understand mechanisms of salinity tolerance. Physiological studies indicate that FL478 shows a lower Na(+) influx, a reduced Na(+) translocation to the shoot, and maint...

The phosphorylated intermediate (EP) of the Na,K-ATPase proteoliposomes (PL) prepared from the electric eel enzyme is composed of an ADP-sensitive K+-insensitive form (E1P), an ADP- and K+-sensitive form (E*P), and a K+-sensitive ADP-insensitive form (E2P). The composition of the intermediate varied with the cholesterol content of the lipid bilayer. The PL containing less than 30 mol % choleste...

Exposure of ARL 15 cells, an established line from adult rat liver, to concentrations of external K+ below 1 mM caused a rapid fall in intracellular K+ and a corresponding rise in intracellular Na+ that became maximal within 12 h. Upon continued exposure to low external K+, these initial changes were followed by a striking recovery such that, by 24 h, intracellular Na+ and K+ concentrations app...