Overcoming: a concept analysis

BACKGROUND. Nurses often work with individuals and populations striving to improve or maintain the quality of their lives. Many, struggling from complex health and social problems, are challenged to surmount barriers to achieve this goal. The growing number of homeless families in the United States represent one such cohort. AIMS. To develop an operational definition of overcoming and explicate its meaning, attributes, and characteristics as it relates to homeless families. METHODS. Using the concept analysis method described by Walker and Avant, along with an extensive literature review, and sample cases pertaining to family homelessness, we delineated the defining attributes, antecedents, consequences, and empirical referents of the concept, overcoming. CONCLUSION. The results of this concept analysis, particularly the relationship of overcoming to family homelessness, provide guidance for further conceptualization and empirical testing, as well as for clinical practice.     

Effect of high and low levels of maternally derived antibodies on porcine circovirus type 2 (PCV2) infection dynamics and production parameters in PCV2 vaccinated pigs under field conditions

The present study aimed to compare the efficacy of a porcine circovirus type 2 (PCV2) commercial vaccine in terms of average daily weight gain (ADWG) as well as infection dynamics in pigs with different maternally derived antibody (MDA) levels. A total of 337 animals from a PCV2 subclinically infected farm were distributed into two groups based on weight and PCV2 antibody levels (high [H] or low [L]) at 2 weeks of age. One week later, these animals were subdivided in four groups according to the treatment received. Vaccinated pigs (H-V and L-V) received 1 mL of a commercial vaccine and NV (H-NV and L-NV) received 1 mL of PBS. All piglets were subsequently bled at 7, 12, 18, 22 and 25 weeks of age and weighted at 12 and 25 weeks of age. V animals showed significantly lower PCV2 infection rates and viral load as well as higher ELISA S/P ratios and ADWG than NV ones. Compared with H-V piglets, L-V pigs showed numerically lower PCV2 infection rates, lower area under the curve of viral load, an earlier seroconversion and a numerically, but not significantly, higher ADWG. In this study, MDA did not seem to interfere with the effect of PCV2 vaccination on ADWG. However, only when a small subpopulation of pigs with the highest ELISA S/P ratios at vaccination was considered, an apparent interference of vaccine efficacy on ADWG was noticed. Therefore, the impact of the putative interference under field conditions is probably negligible for most farms.     

Influence of cytokines onmdr1 expression in human colon carcinoma cell lines: Increased cytoxicity of MDR relevant drugs

We investigated the effects of tumor necrosis factor (TNF) , interferon (IFN) and interleukin-2 (IL-2) on themdr1 gene expression in four human colon carcinoma cell lines (LoVo, HT 115, SW 480, and LS 174T) at different times (8. 24, 48, and 72h). We found no significant changes inmdr1 expression after 8h and 24h of cytokine treatment in all four lines. After 48h and 72h, however, a marked reduction ofmdr1 expression in LoVo, HT 115, and SW 480 cells and an unaffected expression in LS 174T cells was observed. We examined whether the cytokine-mediated reduction ofmdr1 expression correlates to the multidrug resistance (MDR) phenotype. In those cell lines showing a decreasedmdr1 expression after a long-term cytokine pretreatment we found a dramatic enhancement of cytotoxicity of the MDR relevant drugs vincristine and doxorubicin, whereas LS 174T cells remained resistant. By contrast, the simultaneous application of cytokines and cytostatics caused no additive or synergistic effects. We conclude that in certain colon carcinoma cell lines a decreasedmdr1 expression caused by prolonged cytokine pretreatment correlates with an enhanced cytotoxicity of drugs susceptible to MDR as an MDR-overcoming effect.Abbreviations MDR multidrug resistance - TNF tumor necrosis factor - IFN interferon - IL-2 interleukin-2 - Vin vincristine - Dox doxorubicin - IC₅₀ inhibition concentration     

Sequential treatment in disseminated well- and intermediate-differentiated pancreatic neuroendocrine tumors: Common sense or low rationale?

Fortunately, the landscape of the systemic treatment for grade 1 and 2 pancreatic neuroendocrine tumors has changed in the last decade with at least four different alternatives approved in the field. Chemotherapy, somatostatin analogues, sunitinib and everolimus remind valid options according to the most referenced international guidelines. However, and although this is something done in the routine practice, there is a lack of evidence for the use of any of these strategies after failure to the others. Moreover, further sequential alternatives in third or fourth line have never been tested prospectively. The need for a better understanding of the rationale to sequence different systemic options is even greater in non-pancreatic neuroendocrine tumors since available therapies are scarce. Sequential strategies in other solid tumors have led to a clear improvement in overall survival. This is also believed to occur in neuroendocrine tumors but no clear data on it has been delivered yet. We postulate that the different mode of action of the systemic options available for the treatment of neuroendocrine tumors may avoid the complete resistance of one option after the other and that sequential use of these agents will be translated into a longer overall survival of patients. Prospective and randomized trials that seek for the activity of drugs after failure to another systemic alternatives are highly needed in this field of neuroendocrine tumors.