Advance Directives Change Frequently in Nursing Home Residents.

OBJECTIVES: To describe the rate, timing, and pattern of changes in advance directives (ADs) of do not resuscitate (DNR) and do not hospitalize (DNH) orders among new admissions to nursing homes (NHs). DESIGN: A retrospective cohort study. SETTING AND PARTICIPANTS: Admissions to all publicly funded NHs in Ontario, Canada, between January 1, 2013, and December 31, 2017. METHODS: Residents were followed until discharged from incident NH stay, death, or were still present at the end of study (December 31, 2019). They were categorized into 3 mutually exclusive baseline composite AD groups: Full Code, DNR Only, and DNR+DNH. We used Poisson regression models to estimate the incidence rate ratios of AD change between different AD groups and different decision makers for personal care, adjusted for baseline clinical and sociodemographic variables. RESULTS: A total of 102,541 NH residents were eligible for inclusion. Residents with at least 1 AD change accounted for 46% of Full Code, 30% of DNR Only, and 25% of DNR+DNH group. Median time to first AD change ranged between 26 and 55 weeks. For Full Code and DNR Only residents, the most frequent change was to an AD 1 level lower in aggressiveness or intervention, whereas for DNR+DNH residents the most frequent change was to DNR Only. About 16% of residents had 2 or more AD changes during their stay. After controlling for covariates, residents with a DNR-only order or DNR+DNH orders at admission and those with a surrogate decision maker were associated with lower AD change rates. CONCLUSIONS AND IMPLICATIONS: Measuring AD adherence rates that are documented only at a particular time often underestimates the dynamics of AD changes during a resident's stay and results in an inaccurate measure of the effectiveness of AD on resident care. There should be more frequent reviews of ADs as they are quite dynamic. Mandatory review after an acute change in a resident's health would ensure that ADs are current.

Acute care nurses' perceptions of leadership, teamwork, turnover intention and patient safety - a mixed methods study.

BACKGROUND: This study contributes to a small but growing body of literature on how context influences perceptions of patient safety in healthcare settings. We examine the impact of senior leadership support for safety, supervisory leadership support for safety, teamwork, and turnover intention on overall patient safety grade. Interaction effects of predictors on perceptions of patient safety are also examined. METHODS: In this mixed methods study, cross-sectional survey data (N = 185) were collected from nurses and non-physician healthcare professionals. Semi-structured interview data (N = 15) were collected from nurses. The study participants worked in intensive care, general medicine, mental health, or the emergency department of a large community hospital in Southern Ontario. RESULTS: Hierarchical regression analyses showed that staff perceptions of senior leadership (p < 0.001), teamwork (p < 0.01), and turnover intention (p < 0.01) were significantly associated with overall patient safety grade. The interactive effect of teamwork and turnover intention on overall patient safety grade was also found to be significant (p < 0.05). The qualitative findings corroborated the survey results but also helped expand the characteristics of the study's key concepts (e.g., teamwork within and across professional boundaries) and why certain statistical relationships were found to be non-significant (e.g., nurse interviewees perceived the safety specific responsibilities of frontline supervisors much more broadly compared to the narrower conceptualization of the construct in the survey). CONCLUSIONS: The results of the current study suggest that senior leadership, teamwork, and turnover intention significantly impact nursing staff perceptions of patient safety. Leadership is a modifiable contextual factor and resources should be dedicated to strengthen relational competencies of healthcare leaders. Healthcare organizations must also proactively foster inter and intra-professional collaboration by providing teamwork educational workshops or other on-site learning opportunities (e.g., simulation training). Healthcare organizations would benefit by considering the interactive effect of contextual factors as another lever for patient safety improvement, e.g., lowering staff turnover intentions would maximize the positive impact of teamwork improvement initiatives on patient safety.

Turnover intention of hospital staff in Ontario, Canada: exploring the role of frontline supervisors, teamwork, and mindful organizing.

BACKGROUND: This study contributes to a small but growing body of literature on how context influences employee turnover intention. We examine the impact of staff perceptions of supervisory leadership support for safety, teamwork, and mindful organizing on turnover intention. Interaction effects of safety-specific constructs on turnover intention are also examined. METHODS: Cross-sectional survey data were collected from nurses, allied health professionals, and unit clerks working in intensive care, general medicine, mental health, or the emergency department of a large community hospital in Southern Ontario. RESULTS: Hierarchical regression analyses showed that staff perceptions of teamwork were significantly associated with turnover intention (p < 0.001). Direct associations of supervisory leadership support for safety and mindful organizing with turnover intention were non-significant; however, when staff perceived lower levels of mindful organizing at the frontlines, the positive effect of supervisory leadership on turnover intention was significant (p < 0.01). CONCLUSIONS: Our results suggest that, in addition to teamwork perceptions positively affecting turnover intentions, safety-conscious supportive supervisors can help alleviate the negative impact of poor mindful organizing on frontline staff turnover intention. Healthcare organizations should recruit and retain individuals in supervisory roles who prioritize safety and possess adequate relational competencies. They should further dedicate resources to build and strengthen the relational capacities of their supervisory leadership. Moreover, it is important to provide on-site workshops on topics (e.g., conflict management) that can improve the quality of teamwork and consequently reduce employees' intention to leave their unit/organization.

Importance of safety climate, teamwork climate and demographics: understanding nurses, allied health professionals and clerical staff perceptions of patient safety.

BACKGROUND: There is growing evidence regarding the importance of contextual factors for patient/staff outcomes and the likelihood of successfully implementing safety improvement interventions such as checklists; however, certain literature gaps still remain-for example, lack of research examining the interactive effects of safety constructs on outcomes. This study has addressed some of these gaps, together with adding to our understanding of how context influences safety. PURPOSE: The impact of staff perceptions of safety climate (ie, senior and supervisory leadership support for safety) and teamwork climate on a self-reported safety outcome (ie, overall perceptions of patient safety (PS)) were examined at a hospital in Southern Ontario. METHODS: Cross-sectional survey data were collected from nurses, allied health professionals and unit clerks working on intensive care, general medicine, mental health or emergency department. RESULTS: Hierarchical regression analyses showed that perceptions of senior leadership (p<0.001) and teamwork (p<0.001) were significantly associated with overall perceptions of PS. A non-significant association was found between perceptions of supervisory leadership and the outcome variable. However, when staff perceived poorer senior leadership support for safety, the positive effect of supervisory leadership on overall perceptions of PS became significantly stronger (p<0.05). PRACTICE IMPLICATIONS: Our results suggest that leadership support at one level (ie, supervisory) can substitute for the absence of leadership support for safety at another level (ie, senior level). While healthcare organisations should recruit into leadership roles and retain individuals who prioritise safety and possess adequate relational competencies, the field would now benefit from evidence regarding how to build leadership support for PS. Also, it is important to provide on-site workshops on topics (eg, conflict management) that can strengthen working relationships across professional and unit boundaries.

Behavioral Health Factors as Predictors of Emergency Department Use in the High-Risk, High-Cost Medicare Population.

OBJECTIVE: This study measured the presence, extent, and type of behavioral health factors in a high-cost Medicare population and their association with the probability and intensity of emergency department (ED) use. METHODS: Retrospective claims analysis and a comprehensive electronic medical record-based review were conducted for patients enrolled in a 65-month prospective care management program at an academic tertiary medical center (N=3,620). A two-part model used multivariable logistic regression to evaluate the effect of behavioral health factors on the probability of ED use, complemented by a Poisson model to measure the number of ED visits. Control variables included demographic characteristics, poststudy survival, and hierarchical condition category risk score. RESULTS: After analyses controlled for comorbidities and other relevant variables, patients with two or more behavioral health diagnosis categories or two or more behavioral health medications were about twice as likely as those without such categories or medications to use the ED. Patients with a diagnosis category of psychosis, neuropsychiatric disorders, sleep disorders, or adjustment disorders were significantly more likely than those without these disorders to use the ED. Most primary ED diagnoses were not of behavioral health conditions. CONCLUSIONS: Behavioral health factors had a substantial and significant effect on the likelihood and number of ED visits in a population of high-cost Medicare patients. Attention to behavioral health factors as independent predictors of ED use may be useful in influencing ED use in high-cost populations.

An analysis of messages sent between nurses and physicians in deteriorating internal medicine patients to help identify issues in failures to rescue.

OBJECTIVE: To evaluate in patients who deteriorate and require transfer to the intensive care unit (ICU), how many have a critical text message communicating deterioration and what is the quality of this message? Is message quality, message response or the timeliness of rapid response team (RRT) activation related to death? METHODS: We conducted a retrospective chart review of all ICU transfers from General Internal Medicine (GIM) wards from January 2012 until August 2014. All critical messages (CM) in the 48h prior to ICU transfer were analyzed for RRT calling criteria, time to RRT activation, message quality, presence of vitals, and the quality and timeliness of physician response. RESULTS: Of the 236 patients in the study, 93 (39%) had a CM in the 48h prior to ICU transfer. Within this subset, 76 patients did not have prior RRT activation and the median times from CM to RRT activation and CM to ICU transfer were 8.9 [IQR 2.9, 20.7] and 15.6 [IQR 9.0, 28.7] hours, respectively. Only 45% of messages contained 2 or more vitals and only 3% of messages contained Situation, Background, Assessment, and Recommendations (SBAR). Physician response was timely (3 [IQR 2, 17] min) but response quality was poor; nearly one quarter of responses only acknowledged receipt. Among message characteristics, only the number of SBAR elements was correlated with in-hospital survival (p=0.047). CONCLUSION: Communication between nurses and physicians about critically ill patients could be improved. There appear to be significant gaps in the quality of messages, their responses, and delays in RRT activation.

Goals of care discussions among hospitalized long-term care residents: Predictors and associated outcomes of care.

INTRODUCTION: There are limited data on the occurrence, predictors, and impact of goals of care (GOC) discussions during hospitalization for seriously ill elderly patients, particularly for long-term care (LTC) residents. METHODS: The study was a retrospective chart review of 200 randomly sampled LTC residents hospitalized via the emergency department and admitted to the general internal medicine service of 2 Canadian academic hospitals, from January 2012 through December 2012. We applied logistic regression models to identify factors associated with, and outcomes of, these discussions. RESULTS: Overall, 9.4% (665 of 7084) of hospitalizations were patients from LTC. In the sample of 200 patients, 37.5% had a documented discussion. No baseline patient characteristic was associated with GOC discussions. Low Glasgow Coma Scale, high respiratory rate, and low oxygen saturation were associated with discussions. Patients with discussions had higher rates of orders for no resuscitation (80% vs 55%) and orders for comfort measures only (7% vs 0%). In adjusted analyses, patients with discussions had higher odds of in-hospital death (52.0, 95% confidence interval [CI]: 6.2-440.4) and 1-year mortality (4.1, 95% CI: 1.7-9.6). Nearly 75% of patients with a change in their GOC did not have this documented in the discharge summary. CONCLUSION: In hospitalized LTC patients, GOC discussions occurred infrequently and appeared to be triggered by illness severity. Orders for advance directives, in-hospital death, and 1-year mortality were associated with discussions. Rates of GOC documentation in the discharge summary were poor. This study provides direction for developing education and practice standards to improve GOC discussion rates and their communication back to LTC. Journal of Hospital Medicine 2015;11:824-831. © 2015 Society of Hospital Medicine.

Conceptualizing type 2 diabetes and its management.

Type 2 diabetes is growing worldwide due to population growth, increased rates of obesity, unhealthy diet, and physical inactivity. Risk assessment methods can effectively evaluate the risk of diabetes, and a healthy lifestyle can significantly reduce risk or prevent complications of type 2 diabetes. However, risk assessment alone has not significantly improved poor adherence to recommended medical interventions and lifestyle changes. This paper focuses on the challenge of nonadherence and posits that improving adherence requires tailoring interventions that explicitly consider the social determinants of health.

Use of imaging in the emergency department: physicians have limited effect on variation.

PURPOSE: To quantify interphysician variation in imaging use during emergency department (ED) visits and examine the contribution of factors to this variation at the patient, visit, and physician level. MATERIALS AND METHODS: This study was HIPAA compliant and approved by the institutional review board of Partners Healthcare System (Boston, Mass), with waiver of informed consent. In this retrospective study of 88 851 consecutive ED visits during 2011 at a large urban teaching hospital, a hierarchical logistic regression model was used to identify multiple predictors for the probability that low- or high-cost imaging would be ordered during a given visit. Physician-specific random effects were estimated to articulate (by odds ratio) and quantify (by intraclass correlation coefficient [ICC]) interphysician variation. RESULTS: Patient- and visit-level factors found to be statistically significant predictors of imaging use included measures of ED busyness, prior ED visit, referral source to the ED, and ED arrival mode. Physician-level factors (eg, sex, years since graduation, annual workload, and residency training) did not correlate with imaging use. The remaining amount of interphysician variation was very low (ICC, 0.97% for low-cost imaging; ICC, 1.07% for high-cost imaging). These physician-specific odds ratios of imaging estimates were moderately reliable at 0.78 (95% confidence interval [CI]: 0.77, 0.79) for low-cost imaging and 0.76 (95% CI: 0.74, 0.78) for high-cost imaging. CONCLUSION: After careful and comprehensive case-mix adjustment by using hierarchical logistic regression, only about 1% of the variability in ED imaging utilization was attributable to physicians.

Temporal trends in the utilization of echocardiography in Ontario, 2001 to 2009.

The purpose of this study was to examine utilization and growth in echocardiography among the general population of Ontario between 2001 and 2009. The age- and sex-adjusted rates of echocardiography grew from 39.1 per 1,000 persons in 2001 to 59.9 per 1,000 persons in 2009, for an annual rate of increase of 5.5%. Repeat echocardiograms increased at a rate of 10.6% per year and accounted for 25.3% of all procedures in 2009 as compared to 18.5% in 2002. While significant increases in echocardiography utilization were observed, opportunities may exist to improve the clinical utility of the echocardiograms performed in Ontario.

Implementation of a continuous admission model reduces the length of stay of patients on an internal medicine clinical teaching unit.

BACKGROUND: Optimizing hospital operations is a critical issue facing healthcare systems. Reducing unnecessary variation in patient flow is likely to improve efficiency and optimize capacity for hospital inpatients. The objective of this study was to determine whether changing admissions, from a "bolus" system to a "drip" system, would result in a smoothed daily discharge rate, and reduce the length of stay of patients on a General Internal Medicine clinical teaching unit over a period of 1 year. METHODS: We conducted a retrospective analysis of the General Internal Medicine inpatient service at Toronto General Hospital for the 6-month periods from March to August during 2 consecutive years. Length of stay distributions and daily discharge rate variations were compared between the 2 study periods. RESULTS: There were a total of 2734 discharges, 1446 occurring in the pre-change period, and 1288 in the post-change period. There was overall smoothing of the daily discharge rates, and a reduction of 0.3 days in median length of stay in the post-change period (P = 0.0065). CONCLUSIONS: Restructuring the admission system to achieve constant daily admissions to each care team resulted in a smoothing of daily discharge rates and improved operational efficiency with shorter lengths of stay.

An evidence-based case for the value of social workers in efficient hospital discharge.

A study was undertaken to make an evidence-based case for the value of social workers in efficient discharge of patients from acute care hospitals and to assist hospital managers in making informed staffing decisions. Hospital administrative databases from March 1 to November 30, 2008, were used for the analysis of inpatient discharges on days when social workers were on vacation compared with days fully staffed with social workers. Two performance measures, daily discharge rate and average length of stay, were evaluated. During the study period, 1825 patients were discharged from the General Internal Medicine inpatient service. Team discharge rates were significantly lower on social work vacation Fridays versus regular Fridays. In contrast, the average length of stay for patients discharged on social work vacation Fridays was significantly shorter than that for patients discharged on regular Fridays. It was concluded that daily discharge rate better quantified the role of social work in patient discharge. More generally, these results provide preliminary support for the need for adequate social work staffing in timely and efficient patient discharge.

Excellent hospital care for all: open and operating 24/7.

Nights and weekends are the times when most people are admitted to the hospital. They are also synonymous with reduced staffing levels and fewer specialized diagnostic, procedural, and treatment options. Indeed, there is increasing evidence suggesting that patient care is compromised during these times. Equally important is the inefficient use of capital investments during nights and weekends, and inappropriate utilization of hospital beds caused by poor weekend discharge flexibility. We believe that these findings should be of concern not just to hospital care providers, but across care settings and to the general public. In this perspective article, we highlight how our current office-hours system of running hospitals threatens the lives of our sickest, most vulnerable patients, describe solutions currently implemented in hospitals that may alleviate this disparity, and discuss challenges to wider scale implementation.

Energetics and mechanisms of folding and flipping the myristoyl switch in the {beta}-trefoil protein, hisactophilin.

Myristoylation, the covalent linkage of a saturated, C(14) fatty acyl chain to the N-terminal glycine in a protein, plays a vital role in reversible membrane binding and signaling by the modified proteins. Currently, little is known about the effects of myristoylation on protein folding and stability, or about the energetics and molecular mechanisms of switching involving states with sequestered versus accessible myristoyl group. Our analysis of these effects in hisactophilin, a histidine-rich protein that binds cell membranes and actin in a pH-dependent manner, shows that myristoylation significantly increases hisactophilin stability, while also markedly increasing global protein folding and unfolding rates. The switching between sequestered and accessible states is pH dependent, with an apparent pK(switch) of 6.95, and an apparent free energy change of 2.0 kcal·mol(-1). The myristoyl switch is linked to the reversible uptake of ∼1.5 protons, likely by histidine residues. This pH dependence of switching appears to be the physical basis of the sensitive, pH-dependent regulation of membrane binding observed in vivo. We conclude that an increase in protein stability upon modification and burial of the attached group is likely to occur in numerous proteins modified with fatty acyl or other hydrophobic groups, and that the biophysical effects of such modification are likely to play an important role in their functional switches. In addition, the increased global dynamics caused by myristoylation of hisactophilin reveals a general mechanism whereby hydrophobic moieties can make nonnative interactions or relieve strain in transition states, thereby increasing the rates of interconversion between different states.

Real-time operational feedback: daily discharge rate as a novel hospital efficiency metric.

BACKGROUND: Part of delivering quality care means providing it in a timely, efficient manner. Improving the efficiency of care requires measurement. The selection of appropriate indicators that are valid and responsive is crucial to focus improvement initiatives. Indicators of operational efficiency should be conceptually simple, generated in real time, calculated using readily available hospital administrative data, sufficiently granular to reveal detail needed to focus improvement, and correlate with other valid indicators of operational efficiency. DISCUSSION: In this paper, the authors propose daily discharge rate as a novel real-time metric of hospital operational discharge efficiency and compare it with average length of stay. The authors also suggest the use of control charts as an effective way to present daily discharge rate data to clinicians and managers in real time to prompt actionable improvements in discharge efficiency. CONCLUSION: The authors conclude that daily discharge rate has the potential to drive timely improvements in the discharge process and warrants consideration and further study by others interested in improving hospital operational efficiency and the delivery of quality care.

Smoothing inpatient discharges decreases emergency department congestion: a system dynamics simulation model.

BACKGROUND: Timely access to emergency patient care is an important quality and efficiency issue. Reduced discharges of inpatients at weekends are a reality to many hospitals and may reduce hospital efficiency and contribute to emergency department (ED) congestion. OBJECTIVE: To evaluate the daily number of ED beds occupied by inpatients after evenly distributing inpatient discharges over the course of the week using a computer simulation model. METHODS: Simulation modelling study from an academic care hospital in Toronto, Canada. Daily historical data from the general internal medicine (GIM) department between 15 January and 15 December for two years, 2005 and 2006, were used for model building and validation, respectively. RESULTS: There was good agreement between model simulations and historical data for both ED and ward censuses and their respective lengths of stay (LOS), with the greatest difference being +7.8% for GIM ward LOS (model: 9.3 days vs historical: 8.7 days). When discharges were smoothed across the 7 days, the number of ED beds occupied by GIM patients decreased by approximately 27-57% while ED LOS decreased 7-14 hours. The model also demonstrated that patients occupying hospital beds who no longer require acute care have a considerable impact on ED and ward beds. CONCLUSIONS: Smoothing out inpatient discharges over the course of a week had a positive effect on decreasing the number of ED beds occupied by inpatients. Despite the particular challenges associated with weekend discharges, simulation experiments suggest that discharges evenly spread across the week may significantly reduce bed requirements and ED LOS.

Understanding hospital and emergency department congestion: an examination of inpatient admission trends and bed resources.

OBJECTIVE: Patients in the emergency department (ED) who have been admitted to hospital (inpatient "boarders") are associated with ED overcrowding. They are also a symptom of a hospital-wide imbalance between demand and supply of resources. We analyzed the trends of inpatient admissions, ED boarding volumes, lengths of stay and bed resources of 3 major admitting services at our teaching institution. METHODS: We used hospital databases from Jan. 1, 2004, to Dec. 31, 2007, to analyze ED visits that resulted in admission to hospital. RESULTS: During the study period, 21 986 ED patients were admitted to hospital. The percentage of cancer-related admissions to the oncology admitting service decreased from 48% in 2004 to 24% in 2007, and admissions to general internal medicine (GIM) increased nearly 2-fold, from 28% in 2004 to 54% in 2007. In addition, GIM admitted about 10% more myocardial infarction and heart failure patients than did cardiology. General internal medicine constituted the majority of ED boarders and had a median boarding length of stay of approximately 15 hours. Inpatient beds on oncology and cardiology services remained static. CONCLUSION: Without bed capacity to admit more patients, our specialty services relied on GIM to serve as a safety net. At the same time, GIM was cited as a main source of ED congestion as their patients occupied more ED beds for longer periods than any other admitting service. The data presented in this study has helped effect positive change within our institution. Other hospitals running at or near capacity and faced with similar ED congestion may apply the methods we used in this study to analyze the cause and nature of their situation.

Electronic inpatient whiteboards: improving multidisciplinary communication and coordination of care.

OBJECTIVES: Effective and timely communication of information is essential for quality patient care. Information and communication technology tools have the potential to transform and enable health care processes to be more accurate, timely, and integrated. This study describes the development, implementation, and evaluation of an electronic whiteboard in a General Internal Medicine (GIM) inpatient unit of an acute care hospital. METHODS: The development, implementation, and evaluation of the inpatient whiteboard included scope discussions, workflow analyses, communication and training, and issues and enhancement reporting, all managed through a central project team. Evaluation of the whiteboard was two-fold: a survey given to allied health, nursing and physician disciplines (n=120), and an audit performed on whiteboard usage. RESULTS: The whiteboard displays relevant, real-time patient information, in a single, highly visible, user-friendly display. With a quick glance at the whiteboard, one can get an accurate snapshot view of the current patient activity in the unit. Approximately 71% of survey participants believed that the whiteboard improves and standardizes communication within the care team. Further, approximately 62% of the participants agreed that the whiteboard saves them time when searching for information on a patient and their care plan. In addition, the whiteboard has had an impact on the work practices of many GIM care providers, and it along with its users has acted together as agents for positive change. Whiteboard utilization has significantly increased since its implementation. CONCLUSIONS: The success of the whiteboard is in part due to overall change management methodologies through collaborative development throughout the project development lifecycle and subsequent continuous improvement initiatives. The multidisciplinary care team embraced the tool, took ownership of it, and tailored it to meet their needs.

Non-linear effects of temperature and urea on the thermodynamics and kinetics of folding and unfolding of hisactophilin.

Extensive measurements and analysis of thermodynamic stability and kinetics of urea-induced unfolding and folding of hisactophilin are reported for 5-50 degrees C, at pH 6.7. Under these conditions hisactophilin has moderate thermodynamic stability, and equilibrium and kinetic data are well fit by a two-state transition between the native and the denatured states. Equilibrium and kinetic m values decrease with increasing temperature, and decrease with increasing denaturant concentration. The betaF values at different temperatures and urea concentrations are quite constant, however, at about 0.7. This suggests that the transition state for hisactophilin unfolding is native-like and changes little with changing solution conditions, consistent with a narrow free energy profile for the transition state. The activation enthalpy and entropy of unfolding are unusually low for hisactophilin, as is also the case for the corresponding equilibrium parameters. Conventional Arrhenius and Eyring plots for both folding and unfolding are markedly non-linear, but these plots become linear for constant DeltaG/T contours. The Gibbs free energy changes for structural changes in hisactophilin have a non-linear denaturant dependence that is comparable to non-linearities observed for many other proteins. These non-linearities can be fit for many proteins using a variation of the Tanford model, incorporating empirical quadratic denaturant dependencies for Gibbs free energies of transfer of amino acid constituents from water to urea, and changes in fractional solvent accessible surface area of protein constituents based on the known protein structures. Noteworthy exceptions that are not well fit include amyloidogenic proteins and large proteins, which may form intermediates. The model is easily implemented and should be widely applicable to analysis of urea-induced structural transitions in proteins.

Conserved and nonconserved features of the folding pathway of hisactophilin, a beta-trefoil protein.

Based on previous studies of interleukin-1beta (IL-1beta) and both acidic and basic fibroblast growth factors (FGFs), it has been suggested that the folding of beta-trefoil proteins is intrinsically slow and may occur via the formation of essential intermediates. Using optical and NMR-detected quenched-flow hydrogen/deuterium exchange methods, we have measured the folding kinetics of hisactophilin, another beta-trefoil protein that has < 10% sequence identity and unrelated function to IL-1beta and FGFs. We find that hisactophilin can fold rapidly and with apparently two-state kinetics, except under the most stabilizing conditions investigated where there is evidence for formation of a folding intermediate. The hisactophilin intermediate has significant structural similarities to the IL-1beta intermediate that has been observed experimentally and predicted theoretically using a simple, topology-based folding model; however, it appears to be different from the folding intermediate observed experimentally for acidic FGF. For hisactophilin and acidic FGF, intermediates are much less prominent during folding than for IL-1beta. Considering the structures of the different beta-trefoil proteins, it appears that differences in nonconserved loops and hydrophobic interactions may play an important role in differential stabilization of the intermediates for these proteins.