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In vivo K+, Na+, Ca2+ and Cl-activities in the cytosol and the contractile vacuole fluid of Paramecium multimicronucleatum were determined in cells adapted to a number of external osmolarities and ionic conditions by using ion-selective microelectrodes. It was found that: (1) under standardized saline conditions K+ and Cl- were the major osmolytes in both the cytosol and the contractile vacuole fluid; and (2) the osmolarity of the contractile vacuole fluid, determined from K+ and Cl- activities only, was always more than 1.5 times higher than that of the cytosol. These findings indicate that excess cytosolic water crosses the contractile vacuole complex membrane osmotically. Substitution of choline or Ca2+ for K+ in the external solution or the external application of furosemide caused concomitant decreases in the cytosolic K+ and Cl- activities that were accompanied by a decrease in the water segregation activity of the contractile vacuole complex. This implies that the cytosolic K+ and Cl- are actively coimported across the plasma membrane. Thus, the osmotic gradients across both the plasma membrane and the membrane of the contractile vacuole complex ensure a controlled cascade of water flow through the cell that can provide for osmoregulation as well as the possible extrusion of metabolic waste by the contractile vacuole complex.

Background: Hemochromatosis gene (HFE)-associated hereditary hemochromatosis (HH) is characterized by downregulation of hepcidin synthesis, leading to increased intestinal iron absorption. Objectives: The objectives were to characterize and elucidate a possible association between gene expression profile, hepcidin levels, disease severity, and markers of inflammation in HFE-associated HH patients. Methods: Thirty-nine HFE-associated HH patients were recruited and assigned to 2 groups according to genetic profile: C282Y homozygotes in 1 group and patients with H63D, as homozygote or in combination with C282Y, in the other group. Eleven healthy first-time blood donors were recruited as controls. Gene expression was characterized from peripheral blood cells, and inflammatory cytokines and hepcidin-25 isoform were quantified in serum. Biochemical disease characteristics were recorded. Results: Elevated levels of interleukin 8 were observed in a significant higher proportion of patients than controls. In addition, compared to controls, gene expression of ζ-globin was significantly increased among C282Y homozygote patients, while gene expression of matrix metalloproteinase 8, and other neutrophil-secreted proteins, was significantly upregulated in patients with H63D. Conclusion: Different disease signatures may characterize HH patients according to their HFE genetic profile. Studies on larger populations, including analyses at protein level, are necessary to confirm these findings.

Training through simulation has shown to increase relevant and specific skills sets across a wide range of areas in nursing and related professions. Increasing skills has a reciprocal relation to the development of self-efficacy. A study was conducted to assess changes in the development of self-efficacy in simulation training for 2nd year nursing students. Initial emotional states, pre and post self-efficacy, and expert ratings of simulation performance were assessed. Results show that students who displayed an increase in self-efficacy as a result of simulation training were also judged to perform better by expert ratings. The effect of simulation on self-efficacy could be influenced by initial states of physiological activation and over control. Results also showed that initial emotional states did not moderate self-efficacy development on outcome measures. These findings improve our understanding on the relationship between students’ self-efficacy and performance of practical skills and inform pedagogical designs and targeted interventions in relation to feedback and supervision in nursing education.