A comparison between electrical impedance and strain gauge plethysmography for the study of cerebral blood flow in the newborn

This study investigates the possibility of using pulsatile transcephalic impedance changes, delta Z, for the continuous monitoring of cerebral blood flow, CBF, in the sick newborn infant. The performance of the impedance method is compared with the measurement of cranial flow, Fc, using a strain gauge for detecting the predicted changes in cerebral blood flow when the baby breathes 2% CO2 in air, or O2. In all five studies in which measurements were compared in air and CO2 the expected increases in Fc and delta Z were seen. In six of seven studies comparing measurements in air and O2 the expected fall in the variables was seen, indicating reduced cerebral blood flow. The problems of both these methods are discussed and we conclude that the impedance method is as good as the strain gauge method for detecting changes in cerebral blood flow.     

Effect of exogenous surfactant on total respiratory system compliance

We measured total respiratory system compliance (Crs) before and after instilling 25 mg artificial surfactant in 1 ml saline down the endotracheal tube of preterm babies requiring resuscitation at birth, and compared results with data from 6 similar babies receiving saline only. Surfactant did not produce a significant improvement in Crs.     

Differential cellular and molecular effects of bortezomib, a proteasome inhibitor, in human breast cancer cells

The cellular and molecular effects of the proteasome inhibitor bortezomib on breast cancer cells are as yet poorly characterized. Here, in a panel of six breast cancer cell lines, bortezomib reduced viability in a concentration-dependent, time-dependent, and cell line-dependent manner. Proteasome activity was relatively high in two of the three more resistant cell lines. No relationship was observed between bortezomib effects on cell viability and expression/phosphorylation of HER-2, epidermal growth factor receptor (EGFR), AKT, or extracellular signal-regulated kinase 1/2 (ERK1/2). Molecular effects of bortezomib were further studied in SK-BR-3 and BT-474 cells because they share expression of EGFR and overexpression of HER-2 while, in contrast, SK-BR-3 cells were 200-fold more sensitive to this agent. Proteasome activity was inhibited to a similar extent in the two cell lines, and known proteasome substrates accumulated similarly. In SK-BR-3 cells, a marked inhibition of EGFR, HER-2, and AKT phosphorylation was observed at a clinically relevant concentration of bortezomib. In contrast, phosphorylation of Raf/mitogen-activated protein kinase kinase 1/2 (MEK 1/2)/ERK1/2 increased by bortezomib. In BT-474 cells, the effects were much less pronounced. Treatment of SK-BR-3 cells with bortezomib combined with pharmacologic inhibitors of EGFR, phosphatidylinositol 3'-kinase, or MEK resulted in modest or no enhancement of the effects on cell viability. Collectively, these results show that bortezomib has differential cellular and molecular effects in human breast cancer cells. The bortezomib-observed effects on signaling transduction molecules might be relevant to help to design mechanistic-based combination treatments.     

The deconstructing angel: nursing, reflection and evidence-based practice

This paper explores Jacques Derrida's strategy of deconstruction as a way of understanding and critiquing nursing theory and practice. Deconstruction has its origins in philosophy, but I argue that it is useful and relevant as a way of challenging the dominant paradigm of any discipline, including nursing. Because deconstruction is notoriously difficult to define, I offer a number of examples of deconstruction in action. In particular, I focus on three critiques of reflective practice by the meta-narrative of evidence-based practice (EBP) and attempt to show how those critiques can be directed back at EBP itself. I conclude with the observation that EBP is open to many of the criticisms that it directs at other discourses, including problems of a lack of empirical evidence, of distortions due to memory, and of falsification of the 'facts'.