Label-free detection of protein-protein interactions using a calmodulin-modified nanowire transistor.

In this study, we describe a highly sensitive and reusable silicon nanowire field-effect transistor for the detection of protein-protein interactions. This reusable device was made possible by the reversible association of glutathione S-transferase-tagged calmodulin with a glutathione modified transistor. The calmodulin-modified transistor exhibited selective electrical responses to Ca2+ (> or = 1 microM) and purified cardiac troponin I (approximately 7 nM); the change in conductivity displayed a linear dependence on the concentration of troponin I in a range from 10 nM to 1 microM. These results are consistent with the previously reported concentration range in which the dissociation constant for the troponin I-calmodulin complex was determined. The minimum concentration of Ca2+ required to activate calmodulin was determined to be 1 microM. We have also successfully demonstrated that the N-type Ca2+ channels, expressed by cultured 293T cells, can be recognized specifically by the calmodulin-modified nanowire transistor. This sensitive nanowire transistor can serve as a high-throughput biosensor and can also substitute for immunoprecipitation methods used in the identification of interacting proteins.

Experiences of decisional conflict related to epidural labour analgesia among women during late pregnancy in a tertiary hospital in China: a mixed methods study.

BACKGROUND: Research has indicated some women were in a state of uncertainty about pharmacological pain management decisions, which may lead to maternal anxiety and decisional regret. However, little is known about decisional conflict in the choice of epidural labour analgesia amongst Chinese women. AIM: This study aimed to investigate the level of and reasons underlying decisional conflict in Chinese women during their late pregnancy when making a decision on the use of epidural analgesia in labour. METHODS: A convergent parallel mixed methods study was undertaken, that included a quantitative survey (n = 323) and qualitative interviews (n = 17) with women recruited from a tertiary general hospital in Hangzhou, China. The quantitative survey assessed the level of and its influencing factors of women's decisional conflict, while the qualitative interview further explored experiences of and reasons underlying the conflict. FINDINGS: Participants reported a high level of decisional conflict (mean±SD, 39.59±15.92), which related to decision delay and/or negative perceptions about the decision. Multiple stepwise linear regression analysis identified that highest level of education and knowledge of epidural were negatively associated with decisional conflict (p<0.05). Four decision-making styles (rational, dependant, intuitive and avoidant decision-making) associated with different levels of decisional conflict, and four underlying reasons (personal characteristics, informational provision, emotional support and participation in decision-making) of the conflict were thematized. CONCLUSION: Decisional conflict related to epidural labour analgesia is a noteworthy issue amongst women during their late pregnancy. This study suggests a need for provision of family-centred shared decision-making practice about the use of epidural analgesia in labour.