Patients' and physicians' beliefs and attitudes towards integrating personalized risk estimates into patient education about left ventricular assist device therapy

BACKGROUND

Personalized risk (PR) estimates may enhance clinical decision making and risk communication by providing individualized estimates of patient outcomes. We explored stakeholder attitudes toward the utility, acceptability, usefulness and best-practices for integrating PR estimates into patient education and decision making about Left Ventricular Assist Device (LVAD).

METHODS AND RESULTS

As part of a 5-year multi-institutional AHRQ project, we conducted 40 interviews with stakeholders (physicians, nurse coordinators, patients, and caregivers), analyzed using Thematic Content Analysis. All stakeholder groups voiced positive views towards integrating PR in decision making. Patients, caregivers and coordinators emphasized that PR can help to better understand a patient's condition and risks, prepare mentally and logistically for likely outcomes, and meaningfully engage in decision making. Physicians felt it can improve their decision making by enhancing insight into outcomes, enhance tailored pre-emptive care, increase confidence in decisions, and reduce bias and subjectivity. All stakeholder groups also raised concerns about accuracy, representativeness and relevance of algorithms; predictive uncertainty; utility in relation to physician's expertise; potential negative reactions among patients; and overreliance.

CONCLUSION

Stakeholders are optimistic about integrating PR into clinical decision making, but acceptability depends on prospectively demonstrating accuracy, relevance and evidence that benefits of PR outweigh potential negative impacts on decision making quality.

Decision aids for people facing health treatment or screening decisions

BACKGROUND

Patient decision aids are interventions designed to support people making health decisions. At a minimum, patient decision aids make the decision explicit, provide evidence-based information about the options and associated benefits/harms, and help clarify personal values for features of options. This is an update of a Cochrane review that was first published in 2003 and last updated in 2017.

OBJECTIVES

To assess the effects of patient decision aids in adults considering treatment or screening decisions using an integrated knowledge translation approach.

SEARCH METHODS

We conducted the updated search for the period of 2015 (last search date) to March 2022 in CENTRAL, MEDLINE, Embase, PsycINFO, EBSCO, and grey literature. The cumulative search covers database origins to March 2022.

SELECTION CRITERIA

We included published randomized controlled trials comparing patient decision aids to usual care. Usual care was defined as general information, risk assessment, clinical practice guideline summaries for health consumers, placebo intervention (e.g. information on another topic), or no intervention.

DATA COLLECTION AND ANALYSIS

Two authors independently screened citations for inclusion, extracted intervention and outcome data, and assessed risk of bias using the Cochrane risk of bias tool. Primary outcomes, based on the International Patient Decision Aid Standards (IPDAS), were attributes related to the choice made (informed values-based choice congruence) and the decision-making process, such as knowledge, accurate risk perceptions, feeling informed, clear values, participation in decision-making, and adverse events. Secondary outcomes were choice, confidence in decision-making, adherence to the chosen option, preference-linked health outcomes, and impact on the healthcare system (e.g. consultation length). We pooled results using mean differences (MDs) and risk ratios (RRs) with 95% confidence intervals (CIs), applying a random-effects model. We conducted a subgroup analysis of 105 studies that were included in the previous review version compared to those published since that update (n = 104 studies). We used Grading of Recommendations Assessment, Development, and Evaluation (GRADE) to assess the certainty of the evidence.

MAIN RESULTS

This update added 104 new studies for a total of 209 studies involving 107,698 participants. The patient decision aids focused on 71 different decisions. The most common decisions were about cardiovascular treatments (n = 22 studies), cancer screening (n = 17 studies colorectal, 15 prostate, 12 breast), cancer treatments (e.g. 15 breast, 11 prostate), mental health treatments (n = 10 studies), and joint replacement surgery (n = 9 studies). When assessing risk of bias in the included studies, we rated two items as mostly unclear (selective reporting: 100 studies; blinding of participants/personnel: 161 studies), due to inadequate reporting. Of the 209 included studies, 34 had at least one item rated as high risk of bias. There was moderate-certainty evidence that patient decision aids probably increase the congruence between informed values and care choices compared to usual care (RR 1.75, 95% CI 1.44 to 2.13; 21 studies, 9377 participants). Regarding attributes related to the decision-making process and compared to usual care, there was high-certainty evidence that patient decision aids result in improved participants' knowledge (MD 11.90/100, 95% CI 10.60 to 13.19; 107 studies, 25,492 participants), accuracy of risk perceptions (RR 1.94, 95% CI 1.61 to 2.34; 25 studies, 7796 participants), and decreased decisional conflict related to feeling uninformed (MD -10.02, 95% CI -12.31 to -7.74; 58 studies, 12,104 participants), indecision about personal values (MD -7.86, 95% CI -9.69 to -6.02; 55 studies, 11,880 participants), and proportion of people who were passive in decision-making (clinician-controlled) (RR 0.72, 95% CI 0.59 to 0.88; 21 studies, 4348 participants). For adverse outcomes, there was high-certainty evidence that there was no difference in decision regret between the patient decision aid and usual care groups (MD -1.23, 95% CI -3.05 to 0.59; 22 studies, 3707 participants). Of note, there was no difference in the length of consultation when patient decision aids were used in preparation for the consultation (MD -2.97 minutes, 95% CI -7.84 to 1.90; 5 studies, 420 participants). When patient decision aids were used during the consultation with the clinician, the length of consultation was 1.5 minutes longer (MD 1.50 minutes, 95% CI 0.79 to 2.20; 8 studies, 2702 participants). We found the same direction of effect when we compared results for patient decision aid studies reported in the previous update compared to studies conducted since 2015.

AUTHORS' CONCLUSIONS

Compared to usual care, across a wide variety of decisions, patient decision aids probably helped more adults reach informed values-congruent choices. They led to large increases in knowledge, accurate risk perceptions, and an active role in decision-making. Our updated review also found that patient decision aids increased patients' feeling informed and clear about their personal values. There was no difference in decision regret between people using decision aids versus those receiving usual care. Further studies are needed to assess the impact of patient decision aids on adherence and downstream effects on cost and resource use.

Assessment of Uptake Appropriateness of Computed Tomography for Lung Cancer Screening According to Patients Meeting Eligibility Criteria of the US Preventive Services Task Force

Importance

Currently, computed tomography (CT) is used for lung cancer screening (LCS) among populations with various levels of compliance to the eligibility criteria from the US Preventive Services Task Force (USPSTF) recommendations and may represent suboptimal allocation of health care resources.

Objective

To evaluate the appropriateness of CT LCS according to the USPSTF eligibility criteria.

Design, Setting, and Participants

This cross-sectional study used the 2019 Behavioral Risk Factor Surveillance System (BRFSS) survey. Participants included individuals who responded to the LCS module administered in 20 states and had valid answers to questions regarding screening and smoking history. Data were analyzed between October 2021 and August 2022.

Exposures

Screening eligibility groups were categorized according to the USPSTF 2013 recommendations, and subgroups of individuals who underwent LCS were analyzed.

Main Outcomes and Measures

Main outcomes included LCS among the screening-eligible population and the proportions of the screened populations according to compliance categories established from the USPSTF 2013 and 2021 recommendations. In addition, the association between respondents' characteristics and LCS was evaluated for the subgroup who were screened despite not meeting any of the 3 USPSTF screening criteria: age, pack-year, and years since quitting smoking.

Results

A total of 96 097 respondents were identified for the full study cohort, and 2 subgroups were constructed: (1) 3374 respondents who reported having a CT or computerized axial tomography to check for lung cancer and (2) 33 809 respondents who did not meet any screening eligibility criteria. The proportion of participants who were under 50 years old was 53.1%; between 50 and 54, 9.1%; between 55 and 79, 33.8%; and over 80, 4.0%. A total of 51 536 (50.9%) of the participants were female. According to the USPSTF 2013 recommendation, 807 (12.8%) of the screening-eligible population underwent LCS. Among those who were screened, only 807 (20.9%) met all 3 screening eligibility criteria, whereas 538 (20.1%) failed to meet any criteria. Among respondents in subgroup 2, being of older age and having a history of stroke, chronic obstructive pulmonary disease, kidney disease, or diabetes were associated with higher likelihood of LCS.

Conclusions and Relevance

In this cross-sectional study of the BRFSS 2019 survey, the low uptake rate among screening-eligible patients undermined the goal of LCS of early detection. Suboptimal screening patterns could increase health system costs and add financial stress, psychological burden, and physical harms to low-risk patients, while failing to provide high-quality preventive services to individuals at high risk of lung cancer.

AB1441 LEARNING NEEDS ASSESSMENT FOR PATIENTS WITH CANCER AND A PRE-EXISTING AUTOIMMUNE DISEASE WHO ARE CANDIDATES TO RECEIVE IMMUNE CHECKPOINT INHIBITORS

Background

Patients with autoimmune disorders and cancer are at risk of developing immune-related adverse events (irAEs) and increasing flares of their underlying disease with immune checkpoint inhibitors (ICI) and harms and benefits must be weighed.

Objectives

We conducted an assessment of learning needs.

Methods

We interviewed 19 patients who had received an ICI and 20 physicians who provide care for these patients. We asked what do cancer patients with pre-existing autoimmune diseases need to know in order to make an informed decision about whether to receive an ICI.

Results

Fifty-three percent of the patients were female, median age was 62.9 (±10.9). They had rheumatoid arthritis (47.4%), psoriasis (26.3%), Crohn’s disease (10.5%), ankylosing spondylitis (5.3%), systemic lupus erythematosus (5.3%), or ulcerative colitis (5.3%). Half of the patients (52.6%) had a demonstrable disease activity of the autoimmune disease at the time of making the decision on whether to start ICI. Most (84%) of the patients had melanoma, and at the time of the interview 68.4% had completed or discontinued the ICI. Physicians were melanoma oncologists (30%), thoracic-head & neck medical oncologists (25%), rheumatologists (20%), gastroenterologists (10%), and dermatologists (15%) who treat patients with irAEs. Sixty percent were female. Key points mentioned by patients and physicians included information on probability of irAEs and flares of the autoimmune condition with discussion about severity, benefits of ICI, ICI mechanism of action in the context of the autoimmune disease, and management for flare-ups. Key topics raised only by patients included possible reasons for stopping or modifying treatment (for cancer or autoimmune disease), when to contact the provider, possibility of autoimmune disease progression or organ damage, sharing information with other providers, and lifestyle changes that can be done to help.

Conclusion

Although patients and physicians listed common learning points, patients also considered specific needs to increase their self-care. The information derived from this study will be used to develop a decision support tool.

Disclosure of Interests

None declared

Broken Mirror Symmetry of Tracer's Trajectories in Turbulence

Topological properties of physical systems play a crucial role in our understanding of nature, yet their experimental determination remains elusive. We show that the mean helicity, a dynamical invariant in ideal flows, quantitatively affects trajectories of fluid elements: the linking number of Lagrangian trajectories depends on the mean helicity. Thus, a global topological invariant and a topological number of fluid trajectories become related, and we provide an empirical expression linking them. The relation shows the existence of long-term memory in the trajectories: the links can be made of the trajectory up to a given time, with particles positions in the past. This property also allows experimental measurements of mean helicity.

AB0253 A REVIEW OF SMOKING CESSATION STRATEGIES AND LUNG CANCER SCREENING PRACTICES IN PATIENTS WITH RHEUMATOID ARTHRITIS

Background:

Smoking rates among patients with rheumatoid arthritis (RA) exceed those reported in the general population. In addition, people with RA who smoke are more likely to develop lung cancer than smokers who do not have RA.

Objectives:

To identify smoking cessation strategies and lung cancer screening practices in patients with RA.

Methods:

We conducted a review of the literature in electronic databases (i.e., PubMed, EMBASE, Cochrane, Scopus, and Web of Science) from inception until June 2019. We included studies that reported on the results of interventions for smoking cessation or lung cancer screening in patients with RA. We excluded case reports, reviews, guidelines, protocols, or studies on tobacco use not reporting interventions. We included studies published in abstract or full-text format. We extracted study and intervention characteristics including delivery format, timing and results.

Results:

We retrieved 394 relevant citations and ultimately included 9 studies evaluating smoking cessation strategies, and one regarding lung cancer screening practices. Five studies were reported in abstract format. There were 3 studies conducted in the United Kingdom, and one each in Croatia, France, Ireland, New Zealand, Sweden, Spain and United States. Two studies were randomized control trials and the remaining were uncontrolled. Follow-up ranged between 1 month and 24 months, however, one study only reported data on the assessment immediately after the intervention. Sample sizes ranged between 20 and 185 current smokers. Smoking cessation strategies included: 1) brief advice and nicotine replacement therapy + smoking cessation counseling for 3 months; 2) information booklet on harms of smoking (i.e., impact on disease and treatment); 3) spoken information on harms of smoking (i.e., impact on disease and treatment) plus advice to quit smoking; 4) advice to quit smoking plus nicotine replacement; 5) smoking cessation support with contact every 4 weeks; 6) spoken information on harms of smoking (i.e., impact on disease and treatment) plus advice to quit smoking plus nurse telephone visit at 3rdmonth; 6) staff driven tobacco QUIT line referral process; 7) multi-modality intervention with advise to quit smoking plus guidance on safe alcohol use plus dietary advise with booklet and swimming group. The lung cancer screening study reported on a program with nurse evaluation of comorbidities and risk factors, and recommendations for lung cancer screening with a chest X-ray and smoking cessation. Most studies reported benefits when implementing a structured plan to educate, counsel, and offer pharmacological treatment to patients with RA.

Conclusion:

There was large heterogeneity among studies in patient characteristics and interventions proposed, and outcomes. Only 2 studies were randomized clinical trials. Additional controlled studies are needed to determine best practices for smoking cessation and lung cancer screening in patients with RA.

Disclosure of Interests:

None declared

A simplified and versatile calibration method for multi-camera optical systems in 3D particle imaging

This article describes a stereoscopic multi-camera calibration method that does not require any optical model. It is based on a measure of the light propagation within the measurement volume only instead of modeling its entire path up to the sensors. The calibration uses simple plane by plane transformations which allow us to directly link pixel coordinates to light rays. The appeal of the proposed method relies on the combination of its simplicity of implementation (it is particularly easy to apply in any sophisticated optical imaging setup), its versatility (it can easily handle index-of-refraction gradients, as well as complex optical arrangements), and its accuracy {we show that the proposed method gives better accuracy than commonly used techniques, based on Tsai's simple pinhole camera model [R. Tsai, J. Rob. Autom. 3, 323 (1987)], while its numerical implementation remains extremely simple}. Based on ideas that have been available in the fluid mechanics community, this method is a compact turn-key algorithm that can be implemented with open-source routines.

Equilibrium position of a rigid sphere in a turbulent jet: A problem of elastic reconfiguration

The position of floating spheres trapped within an immersed turbulent water jet is investigated. Using the self-similarity properties of the jet velocity profile, the equilibrium problem is formulated in a rescaled space where the sphere is static and deformable. This approach is found to be related to a problem of elastic reconfiguration where elasticity arises here from the geometry of the flow instead of an actual deformation of a body.

Estimating two-point statistics from derivatives of a signal containing noise: Application to auto-correlation functions of turbulent Lagrangian tracks

This article describes a method for calculating moments and correlation functions of signal derivatives, which were rid of experimental noise without the use of filtering operations. The method is based on the computation of the ensemble-average of different time (or spatial) increments of the signal. The hypotheses are that the noise is white and not correlated with the signal; however, the method is also shown to work with colored noise. The method is first developed, considering white noise, and benchmarked with synthetic trajectories containing noise with variable signal-to-noise ratios. It is then tested on experimental trajectories in the context of Lagrangian tracking of particles in turbulent flows, either containing a short-correlated noise or a colored noise.

Abstract 2574: Outcomes of contralateral prophylactic mastectomy in relation to familial history: a decision analysis

Purpose

Family history of breast cancer is associated with an increased risk of contralateral breast cancer (CBC) even in the absence of mutations in the breast cancer susceptibility genes BRCA1/2. We compared quality-adjusted survival outcomes after contralateral prophylactic mastectomy (CPM) with surveillance only (no CPM) among women with breast cancer in relation to degree of family history.

Methods

We created a microsimulation model for women with a first-degree, second-degree and no family history treated for a stage I, II, or III estrogen receptor (ER)-positive or -negative breast cancer at the ages of 40, 50, 60, and 70 years. The model incorporated a 10-year post-treatment period for risk of developing CBC and/or dying of the primary cancer or CBC. For each patient profile, we used 100,000 microsimulation trials to estimate the quality-adjusted life expectancy for two clinical strategies: CPM and no CPM.

Results

CPM had a minimal improvement on quality-adjusted life expectancy among women age 50 to 60 with no or a unilateral first or second-degree family history (range -.06 to 0.31) and was unfavorable for the majority of women age 70 with stage III breast cancer regardless of degree of family history (range -.08 to -.02). Sensitivity analysis showed the highest predicted benefit of CPM with 95% risk reduction was 0.57 QALY for a 40-year-old woman with stage I breast cancer who had a first-degree relative with bilateral breast cancer.

Conclusion

Women age 40 years with stage I breast cancer and a first-degree relative with bilateral breast cancer have a QALY benefit from CPM similar to that reported for BRCA1/2 mutation carriers. For the majority of women, having a family history does not improve the minimal effect of CPM on quality-adjusted life expectancy.

Citation Format: Kalatu R. Davies, Abenaa Brewster, Isabelle Bedrosian, Patricia Parker, Melissa A. Crosby, Susan K. Peterson, Yu Shen, Robert Volk, Scott B. Cantor. Outcomes of contralateral prophylactic mastectomy in relation to familial history: a decision analysis. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2574.

Stochastic dynamics of particles trapped in turbulent flows

The long-time dynamics of large particles trapped in two nonhomogeneous turbulent shear flows is studied experimentally. Both flows present a common feature, a shear region that separates two colliding circulations, but with different spatial symmetries and temporal behaviors. Because large particles are less and less sensitive to flow fluctuations as their size increases, we observe the emergence of a slow dynamics corresponding to back-and-forth motions between two attractors, and a super-slow regime synchronized with flow reversals when they exist. Such dynamics is substantially reproduced by a one-dimensional stochastic model of an overdamped particle trapped in a two-well potential, forced by a colored noise. An extended model is also proposed that reproduces observed dynamics and trapping without potential barrier: the key ingredient is the ratio between the time scales of the noise correlation and the particle dynamics. A total agreement with experiments requires the introduction of spatially nonhomogeneous fluctuations and a suited confinement strength.

Chaotic mixing in effective compressible flows

We study numerically joint mixing of salt and colloids by chaotic advection and how salt inhomogeneities accelerate or delay colloid mixing by inducing a velocity drift V(dp) between colloids and fluid particles as proposed in recent experiments [J. Deseigne et al., Soft Matter 10, 4795 (2014)]. We demonstrate that because the drift velocity is no longer divergence free, small variations to the total velocity field drastically affect the evolution of colloid variance σ(2) = 〈C(2)〉-〈C〉(2). A consequence is that mixing strongly depends on the mutual coherence between colloid and salt concentration fields, the short time evolution of scalar variance being governed by a new variance production term P = -〈C(2)∇ · V(dp)〉/2 when scalar gradients are not developed yet so that dissipation is weak. Depending on initial conditions, mixing is then delayed or enhanced, and it is possible to find examples for which the two regimes (fast mixing followed by slow mixing) are observed consecutively when the variance source term reverses its sign. This is indeed the case for localized patches modeled as Gaussian concentration profiles.

Long-term memory in experiments and numerical simulations of hydrodynamic and magnetohydrodynamic turbulence

We analyze time series stemming from experiments and direct numerical simulations of hydrodynamic and magnetohydrodynamic turbulence. Simulations are done in periodic boxes, but with a volumetric forcing chosen to mimic the geometry of the flow in the experiments, the von Kármán swirling flow between two counterrotating impellers. Parameters in the simulations are chosen to (within computational limitations) allow comparisons between the experiments and the numerical results. Conducting fluids are considered in all cases. Two different configurations are considered: a case with a weak externally imposed magnetic field and a case with self-sustained magnetic fields. Evidence of long-term memory and 1/f noise is observed in experiments and simulations, in the case with weak magnetic field associated with the hydrodynamic behavior of the shear layer in the von Kármán flow, and in the dynamo case associated with slow magnetohydrodynamic behavior of the large-scale magnetic field.

Does the diagnosing urologist influence choice of initial active treatment versus observation in older men with favorable prostate cancer?

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Background: Upfront treatment of older men with favorable prostate cancer yields substantial morbidity but does not improve survival. Deferring treatment in favor of observation promises to reduce morbidity without compromising survival, yet few patients select observation. Prior literature focuses on patient factors contributing to active treatment but the influence of the patient’s urologist on treatment choice remains uncertain. Methods: We identified men age 66 and older with favorable prostate cancer (cT1c or cT2; Gleason 6) diagnosed from 2004-2007 in the SEER-Medicare and Texas Cancer Registry-Medicare databases whose catchments include 34% of the United States (US). Diagnosing urologist, practice setting and cancer-directed treatment within 12 month of diagnosis (prostatectomy, radiotherapy, cryotherapy or androgen deprivation) were determined from claims data. Physician characteristics were obtained from the AMA Master File. Fixed effect and random effect hierarchical multivariate models evaluated physician variation and factors associated with observation. Results: 17,468 patients received care from 2,613 urologists. 64% of patients had T1c cancer. 85% received active treatment and 15% had observation. Even among men 80 and older, 67% received active treatment. The diagnosing urologist accounted for 10% of the variance in choice of active treatment versus observation. After adjusting for patient factors, urologists practicing in an office setting (vs. hospital; p<0.001) and not trained in the US (vs. US-trained; p=0.006) were less likely to manage patients with observation. With adjustment for case mix, only 3.5% of urologists demonstrated a higher than average likelihood of managing their patients with observation; 34% of men diagnosed by these urologists were observed. Conclusions: The vast majority of older men, even those over 80, received active treatment for favorable prostate cancer. The diagnosing urologist contributed to variation in the choice of treatment versus observation. Less than 5% of urologists demonstrated higher than average use of observation suggesting widespread bias against observation during the study era.

Clustering of finite-size particles in turbulence

We investigate experimentally the spatial distributions of heavy and neutrally buoyant particles of finite size in a fully turbulent flow. Because their Stokes number (i.e., the ratio of the particle viscous relaxation time to a typical flow time scale) is close to unity, one may expect both classes of particles to aggregate in specific flow regions. This is not observed. Using a Voronoï analysis we show that neutrally buoyant particles sample turbulence homogeneously, whereas heavy particles do cluster. These results show that several dimensionless numbers are needed in the modeling (and understanding) of the behavior of particles entrained by turbulent motions.

Chaotic dynamos generated by a turbulent flow of liquid sodium

We report the observation of several dynamical regimes of the magnetic field generated by a turbulent flow of liquid sodium (VKS experiment). Stationary dynamos, transitions to relaxation cycles or to intermittent bursts, and random field reversals occur in a fairly small range of parameters. Large scale dynamics of the magnetic field result from the interactions of a few modes. The low dimensional nature of these dynamics is not smeared out by the very strong turbulent fluctuations of the flow.

Generation of a magnetic field by dynamo action in a turbulent flow of liquid sodium

We report the observation of dynamo action in the von Kármán sodium experiment, i.e., the generation of a magnetic field by a strongly turbulent swirling flow of liquid sodium. Both mean and fluctuating parts of the field are studied. The dynamo threshold corresponds to a magnetic Reynolds number R(m) approximately 30. A mean magnetic field of the order of 40 G is observed 30% above threshold at the flow lateral boundary. The rms fluctuations are larger than the corresponding mean value for two of the components. The scaling of the mean square magnetic field is compared to a prediction previously made for high Reynolds number flows.

Developing a quality criteria framework for patient decision aids: online international Delphi consensus process

OBJECTIVE

To develop a set of quality criteria for patient decision support technologies (decision aids).

DESIGN AND SETTING

Two stage web based Delphi process using online rating process to enable international collaboration.

PARTICIPANTS

Individuals from four stakeholder groups (researchers, practitioners, patients, policy makers) representing 14 countries reviewed evidence summaries and rated the importance of 80 criteria in 12 quality domains on a 1 to 9 scale. Second round participants received feedback from the first round and repeated their assessment of the 80 criteria plus three new ones.

MAIN OUTCOME MEASURE

Aggregate ratings for each criterion calculated using medians weighted to compensate for different numbers in stakeholder groups; criteria rated between 7 and 9 were retained.

RESULTS

212 nominated people were invited to participate. Of those invited, 122 participated in the first round (77 researchers, 21 patients, 10 practitioners, 14 policy makers); 104/122 (85%) participated in the second round. 74 of 83 criteria were retained in the following domains: systematic development process (9/9 criteria); providing information about options (13/13); presenting probabilities (11/13); clarifying and expressing values (3/3); using patient stories (2/5); guiding/coaching (3/5); disclosing conflicts of interest (5/5); providing internet access (6/6); balanced presentation of options (3/3); using plain language (4/6); basing information on up to date evidence (7/7); and establishing effectiveness (8/8).

CONCLUSIONS

Criteria were given the highest ratings where evidence existed, and these were retained. Gaps in research were highlighted. Developers, users, and purchasers of patient decision aids now have a checklist for appraising quality. An instrument for measuring quality of decision aids is being developed.

Transport of magnetic field by a turbulent flow of liquid sodium

We study the effect of a turbulent flow of liquid sodium generated in the von Kármán geometry, on the localized field of a magnet placed close to the frontier of the flow. We observe that the field can be transported by the flow on distances larger than its integral length scale. In the most turbulent configurations, the mean value of the field advected at large distance vanishes. However, the rms value of the fluctuations increases linearly with the magnetic Reynolds number. The advected field is strongly intermittent.

Induction, helicity, and alpha effect in a toroidal screw flow of liquid gallium

We investigate experimentally induction mechanisms in a screw flow of gallium in a toroidal channel. The flow is nonstationary and operated in a spin-down regime: the channel (and fluid) are initially set into solid body rotation; as the channel is stopped the fluid is set into strong helical motion by diverters located inside the channel. In this study, we put a particular emphasis on the induction generated by these helical motions, which are expected to develop over the entire range of turbulent scales. We apply an external magnetic field either perpendicular to the channel axis parallel to it. At large scales the nonlinear induction mechanisms are associated with the Parker stretch and twist effect and with the expulsion due to overall rotation. Induction mechanisms can also originate in the small scale helicity as in the alpha induction effect of mean-field magnetohydrodynamics. Our measurements yield an upper bound for the alpha coefficient, significantly lower than estimates based on dimensional analysis. We discuss the consequences of our observations for the engineering of homogeneous dynamos in the laboratory.

Backward supercontinuum emission from a filament generated by ultrashort laser pulses in air

Backward emission of the supercontinuum from a light filament induced by high-intensity femtosecond laser pulses propagating in air has been observed to be enhanced compared with linear Rayleigh-Mie scattering. This enhancement is interpreted as a nonlinear scattering process onto longitudinal refractive-index changes induced by the laser pulse itself. The spectral dependence of the supercontinuum angular distribution is also investigated.

Inhibition of ubiquitin-proteasome pathway-mediated I kappa B alpha degradation by a naturally occurring antibacterial peptide

Induction of NF-kappaB-dependent gene expression plays an important role in a number of biological processes including inflammation and ischemia-reperfusion injury. However, few attempts aimed at selective regulation of this transcription factor have been successful. We report here that a naturally occurring antibacterial peptide PR39 reversibly binds to the alpha 7 subunit of the 26S proteasome and blocks degradation of NF-kappa B inhibitor I kappa B alpha by the ubiquitin-proteasome pathway without affecting overall proteasome activity. I kappa B alpha phosphorylation and ubiquitination occur normally after PR39 treatment, and binding of valosin-containing proteins is not impaired. The inhibition of I kappa B alpha degradation abolishes induction of NF-kappa B-dependent gene expression in cell culture and in mouse models of acute pancreatitis and myocardial infarction, including upregulation of endothelial adhesion proteins VCAM-1 and ICAM-1. In the latter model, sustained infusion of PR39 peptide resulted in significant reduction of myocardial infarct size. PR39 and related peptides may provide novel means to regulate cellular function and to control of NF-kappa B-dependent gene expression for therapeutic purposes.

Anti-angiogenic cues from vascular basement membrane collagen

Vascular basement membrane is an important structural component of blood vessels and has been shown to interact with and modulate vascular endothelial behavior during angiogenesis. During the inductive phase of tumor angiogenesis, this membrane undergoes many degradative and structural changes and reorganizes to a native state around newly formed capillaries in the resolution phase. Such matrix changes are potentially associated with molecular modifications that include expression of matrix gene products coupled with conformational changes, which expose cryptic protein modules for interaction with the vascular endothelium. We speculate that these interactions provide important endogenous angiogenic and anti-angiogenic cues. In this report, we identify an important antiangiogenic vascular basement membrane-associated protein, the 26-kDa NC1 domain of the alpha1 chain of type IV collagen, termed arresten. Arresten was isolated from human placenta and produced as a recombinant molecule in Escherichia coli and 293 embryonic kidney cells. We demonstrate that arresten functions as an anti-angiogenic molecule by inhibiting endothelial cell proliferation, migration, tube formation, and Matrigel neovascularization. Arresten inhibits the growth of two human xenograft tumors in nude mice and the development of tumor metastases. Additionally, we show that the anti-angiogenic activity of arresten is potentially mediated via mechanisms involving cell surface proteoglycans and the alpha1beta1 integrin on endothelial cells. Collectively, our results suggest that arresten is a potent inhibitor of angiogenesis with a potential for therapeutic use.

PR39, a peptide regulator of angiogenesis

Although tissue injury and inflammation are considered essential for the induction of angiogenesis, the molecular controls of this cascade are mostly unknown. Here we show that a macrophage-derived peptide, PR39, inhibited the ubiquitin-proteasome-dependent degradation of hypoxia-inducible factor-1alpha protein, resulting in accelerated formation of vascular structures in vitro and increased myocardial vasculature in mice. For the latter, coronary flow studies demonstrated that PR39-induced angiogenesis resulted in the production of functional blood vessels. These findings show that PR39 and related compounds can be used as potent inductors of angiogenesis, and that selective inhibition of hypoxia-inducible factor-1alpha degradation may underlie the mechanism of inflammation-induced angiogenesis.

The role of syndecan cytoplasmic domain in basic fibroblast growth factor-dependent signal transduction

To determine the role played by syndecan-4 cytoplasmic domain in the mediation of basic fibroblast growth factor (bFGF) signaling, immortalized human cells (ECV) were used to generate cell lines expressing constructs encoding full-length sequences for syndecan-4 (S4), syndecan-1 (S1), glypican-1 (G1), or chimeric proteins consisting of the ectoplasmic domain of glypican-1 linked to the transmembrane/cytoplasmic domain of syndecan-4 (G1-S4c) and the ectoplasmic domain of syndecan-4 linked to the glypican-1 glycosylphosphatidylinositol (GPI) anchor sequence (S4-GPI). Vector-transduced cells (VC) were used as controls. Expression of all these proteoglycans (except for the vector control) significantly increased cell-associated heparan sulfate mass and the number of low affinity bFGF-binding sites. However, in low serum medium, the addition of bFGF stimulated growth and migration of cells expressing S4 and G1-S4c constructs but not G1, S1, S4-GPI, or VC cells. Similar results were obtained using Matrigel growth assays. Mutations of heparan sulfate attachment sites on S4 construct abolished syndecan-4-dependent augmentation of bFGF responses. We conclude that cytoplasmic tail of syndecan-4 plays an important role in bFGF-mediated signal transduction.

Kringle 5 causes cell cycle arrest and apoptosis of endothelial cells

Angiostatin which contains the first four kringle domains of plasminogen has been documented to be a potent inhibitor of angiogenesis. More recently, another kringle structure within plasminogen but outside angiostatin, known as kringle 5 (K5), was found to inhibit endothelial cell proliferation and migration. Here, we report the cloning and expression of mouse kringle 5 (rK5) in a bacterial expression system. The protein was purified to homogeneity using a Ni-NTA column. rK5 inhibited both proliferation and migration of endothelial cells with ED50's of 10 nM and < 500 nM, respectively. In addition, we show for the first time that rK5 causes cell cycle arrest and apoptosis, shedding further insight into rK5's mechanism of action. Finally, we show that these actions are endothelial cell specific.

Cloning, expression, and in vitro activity of human endostatin

Endostatin, a 20 kDa C-terminal fragment of collagen XVIII, is a specific inhibitor of endothelial cell proliferation and angiogenesis. In the present study, we have expressed human endostatin in a yeast expression system (10 mg/L). The recombinant protein was expressed in a soluble form and purified to homogeneity. It specifically inhibited the proliferation and migration of endothelial cells. In addition, we report for the first time that endostatin caused G1 arrest of endothelial cells. Also, we show that endostatin treatment resulted in apoptosis of HUVE and HMVE cells and that all of these effects do not occur in nonendothelial cells. Collectively, these findings demonstrate the expression of a biologically active form of human endostatin in yeast and provide important mechanistic insight into endostatin action on endothelial cells.

Antiangiogenic activity of restin, NC10 domain of human collagen XV: comparison to endostatin

Based on a homology search with endostatin, the C-terminus 185 aa of collagen XVIII, we report the cloning, expression, and antiangiogenic activity of a 22 kDa human collagen XV fragment, that we have named restin. Restin was expressed in the prokaryotic pET expression system. We have shown that restin inhibits the migration of endothelial cells in vitro but has no effect on the proliferation of these cells. A polyclonal antibody raised against endostatin cross-reacted with restin. Systemic administration of restin suppressed the growth of tumors in a xenograft renal carcinoma model.

Endostatin: yeast production, mutants, and antitumor effect in renal cell carcinoma

Endostatin is a Mr 20,000 COOH-terminal fragment of collagen XVIII that inhibits the growth of several primary tumors. We report here the cloning and expression of mouse endostatin in both prokaryotic and eukaryotic expression systems. Soluble recombinant protein expressed in yeast (15-20 mg/L) inhibited the proliferation and migration of endothelial cells in response to stimulation by basic fibroblast growth factor. A rabbit polyclonal antibody was raised that showed positive immunoreactivity to the recombinant protein expressed from both systems. Importantly, the biological activity of the mouse recombinant protein could be neutralized by this antiserum in both endothelial proliferation and chorioallantoic membrane assays. Systemic administration of endostatin at 10 mg/kg suppressed the growth of renal cell cancer in a nude mouse model. The inhibition of tumor growth with soluble yeast-produced protein was comparable to that obtained with non-refolded precipitated protein expressed from bacteria. In addition, two closely related COOH-terminal deletion mutants of endostatin were also tested and showed strikingly differing activity. Collectively, these findings demonstrate the expression of a biologically active form of mouse endostatin in yeast, define a role for the molecule in inhibiting endothelial cell migration, extend its antitumor effects to renal cell carcinoma, and provide a formal proof (via the neutralizing antiserum experiments and the mutant data) that endostatin (and not a possible contaminant) acts as an antiangiogenic agent. Finally, the high level expression of mouse endostatin in yeast serves as an endotoxin free, soluble source of protein for fundamental studies on the mechanisms of tumor growth suppression by angiogenesis inhibitors.

Macrophage-dependent regulation of syndecan gene expression

Heparan sulfates in the extracellular matrix are required for a variety of biological processes, including cellular response to heparin-binding growth factors. However, little is known regarding the regulation of their expression and composition under pathophysiological conditions. In the present study, we have investigated the regulation of expression of two key heparan sulfate chain-carrying core proteins, syndecan-1 and syndecan-4, in a mouse/rat infarct model of tissue injury and repair. Induction of myocardial infarction was associated with a prompt increase in expression of both syndecan genes. Although infiltrating macrophages accounted for a substantial increase in syndecan expression, increased expression was noted in the levels of syndecan-1 mRNA in endothelial cells and syndecan-4 mRNA in cardiac myocytes. This increase in expression was limited to the immediate peri-infarct region and was absent from remote areas of the left or right ventricles. The influx of blood-derived macrophages in the heart correlated with the appearance of PR-39 peptide, which has previously been shown to increase syndecan expression in vitro. Studies in the op/op mice strain (which demonstrates sharply reduced levels of circulating monocytes) showed that myocardial infarction was associated with markedly reduced levels of macrophage influx and corresponding reduction in the expression of PR-39 and both syndecan genes. Pretreatment of op/op mice with granulocyte macrophage colony-stimulating factor restored myocardial macrophage content with corresponding restoration of PR-39/syndecan expression. In summary, myocardial infarction is associated with a distinct spatial and temporal pattern of syndecan-1 and -4 gene expression, which is induced by an influx of blood-derived macrophages.

Biosynthesis of riboflavin. Studies on the reaction mechanism of 6,7-dimethyl-8-ribityllumazine synthase

The lumazine synthase/riboflavin synthase complex of Bacillus subtilis consists of an icosahedral capsid of 60 beta subunits surrounding a core of 3 alpha subunits. The beta subunits catalyze the condensation of 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione with (3S)-3,4-dihydroxy-2-butanone under formation of 6,7-dimethyl-8-ribityllumazine. This intermediate is converted to riboflavin by the alpha subunits via an unusual dismutation yielding 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione as second product. (3R)- and (3S)-3,4-dihydroxy-2-butanone 4-phosphate were synthesized. Both enantiomers can serve as substrate for 6,7-dimethyl-8-ribityllumazine synthase. The reaction rate of the natural S-enantiomer is about 6-fold higher than that of the R-enantiomer. The Km value for (3S)-3,4-dihydroxy-2-butanone 4-phosphate is 130 microM, and the Km value for the pyrimidine substrate is 5 microM. Diacetyl and 3,4-dihydroxy-2-butanone 3-phosphate do not serve as substrates for lumazine synthase. The enzyme-catalyzed condensation of the carbohydrate with the pyrimidine is strictly regiospecific. The enzyme does not catalyze the exchange of protons between (3S)-3,4-dihydroxy-2-butanone 4-phosphate and solvent water in the absence of the pyrimidine cosubstrate. A reaction mechanism starting with the formation of a Schiff base followed by elimination of phosphate and cyclization is proposed. The lumazine synthase activities of the native enzyme complex and of reconstituted, hollow beta 60 capsids are virtually identical (about 12,000 nmol mg-1 h-1).

Genomic structure and chromosomal location of the rat gene encoding the zinc finger transcription factor Kid-1

We have previously cloned and sequenced a novel zinc finger cDNA, Kid-1, from the rat. Because of its developmentally regulated expression pattern and its suppression after renal injury, as well as its kidney-predominant expression, we propose that Kid-1 is likely to play an important role in renal gene regulation. Kid-1 encodes a predicted protein with 13 zinc fingers at the carboxy end and Krüppel-associated box (KRAB) A and B regions at the amino terminus. Expression of a Kid-1-GAL4 chimeric protein results in strong transcriptional repression of cotransfected constructs containing GAL4 binding sites and a chloramphenicol acetyl transferase gene driven by either a minimal promoter or a SV40 enhancer. We now report the cloning, structural organization, and chromosomal localization of the Kid-1 gene. The Kid-1 gene is composed of four exons and three introns, closely reflecting the organization of the Kid-1 protein. The KRAB A and B regions are encoded by the second and third exons, respectively. The entire zinc finger region is encoded by the fourth exon. Using a combination of linkage analysis and somatic cell hybrid analysis, Kid-1 was mapped to rat chromosome (RNO) 10. Kid-1, Il3, and Sparc form a tight linkage group on RNO10. Regional sublocalization to RNO10q21.3-q22 was established by fluorescence in situ hybridization.

Differential induction of eicosanoid synthesis in monocytic cells treated with retinoic acid and 1,25-dihydroxy-vitamin D3

Synthesis and release of eicosanoids is characteristic to mature monocytes, while in undifferentiated premonocytic cells arachidonic acid (AA) metabolism is barely detectable. Since some vitamins and cytokines induce differentiation of these cells to a more monocyte-like cell type, we evaluated the effect of retinoic acid (RA), 1,25(OH)2-vitamin D3 (1,25-D3) and interferon-gamma (IFN-gamma) on AA metabolism in the human premonocytic cell lines U937 and THP-1. In U937 cells, differentiation with RA (1 microM) followed by stimulation with the calcium ionophore A23187 (10 microM) or platelet activating factor (PAF; 100 nM) significantly increased synthesis of immunoreactive 6-keto PGF1 alpha, TxB2 and PGE2 5- to 6-fold. Analysis of AA metabolism in RA-differentiated cells prelabelled with [3H]-AA revealed the formation of additional radioactive compounds which coeluted with standards for PGF2 alpha, PGD2 and 12-hydroxyheptadecatrienoic acid (HHT). The structural identity of 6-keto PGF1 alpha, TxB2, PGE2 and HHT was confirmed by gas chromatography-mass spectrometry (GC-MS). In parallel, RA induced the expression of the monocytic surface antigen CD11b, but not CD14. Differentiation with 1,25-D3 (10 nM) only marginally increased stimulated eicosanoid formation, while it more effectively induced expression of CD11b and CD14. Pretreatment with IFN-gamma (100 IU/ml) slightly increased stimulus-dependent AA metabolism, but did not induce expression of CD11b or CD14. Induction of eicosanoid synthesis by RA was further confirmed in THP-1 cells. These data indicate that RA most effectively induced cyclooxygenase activity and stimulus-dependent eicosanoid formation in U937 and THP-1 cells. Furthermore, since expression of monocytic surface antigens differed between RA and 1,25-D3, it is suggested that induction of cyclooxygenase activity may correlate to differentiation into distinct monocytic phenotypes.

Biosynthesis of riboflavin: cloning, sequencing, mapping, and expression of the gene coding for GTP cyclohydrolase II in Escherichia coli

GTP cyclohydrolase II catalyzes the first committed step in the biosynthesis of riboflavin. The gene coding for this enzyme in Escherichia coli has been cloned by marker rescue. Sequencing indicated an open reading frame of 588 bp coding for a 21.8-kDa peptide of 196 amino acids. The gene was mapped to a position at 28.2 min on the E. coli chromosome and is identical with ribA. GTP cyclohydrolase II was overexpressed in a recombinant strain carrying a plasmid with the cloned gene. The enzyme was purified to homogeneity from the recombinant strain. The N-terminal sequence determined by Edman degradation was identical to the predicted sequence. The sequence is homologous to the 3' part of the central open reading frame in the riboflavin operon of Bacillus subtilis.

Biosynthesis of riboflavin: cloning, sequencing, and expression of the gene coding for 3,4-dihydroxy-2-butanone 4-phosphate synthase of Escherichia coli

3,4-Dihydroxy-2-butanone 4-phosphate is biosynthesized from ribulose 5-phosphate and serves as the biosynthetic precursor for the xylene ring of riboflavin. The gene coding for 3,4-dihydroxy-2-butanone 4-phosphate synthase of Escherichia coli has been cloned and sequenced. The gene codes for a protein of 217 amino acid residues with a calculated molecular mass of 23,349.6 Da. The enzyme was purified to near homogeneity from a recombinant E. coli strain and had a specific activity of 1,700 nmol mg-1 h-1. The N-terminal amino acid sequence and the amino acid composition of the protein were in agreement with the deduced sequence. The molecular mass as determined by ion spray mass spectrometry was 23,351 +/- 2 Da, which is in agreement with the predicted mass. The previously reported loci htrP, "luxH-like," and ribB at 66 min of the E. coli chromosome are all identical to the gene coding for 3,4-dihydroxy-2-butanone 4-phosphate synthase, but their role had not been hitherto determined. Sequence homology indicates that gene luxH of Vibrio harveyi and the central open reading frame of the Bacillus subtilis riboflavin operon code for 3,4-dihydroxy-2-butanone 4-phosphate synthase.

Biosynthesis of riboflavin. Studies on the mechanism of L-3,4-dihydroxy-2-butanone 4-phosphate synthase

The riboflavin precursor, L-3,4-dihydroxy-2-butanone 4-phosphate, is formed from D-ribulose 5-phosphate by a single 24-kDa enzyme. Studies with various specifically 13C-labeled D-ribulose 5-phosphates as substrate showed that the carbon atoms 1-3 of the enzyme product correspond to carbon atoms 1-3 of the substrate, whereas C-4 of the product stems from C-5 of the substrate. Carbon atom 4 of the substrate is released as formate together with the hydrogen atom attached to it. The skeletal rearrangement which leads to the loss of C-4 and the direct linkage between C-3 and C-5 of the substrate is an intramolecular reaction. The hydrogen atom at C-3 of the enzyme product is introduced from solvent water. A reaction mechanism which is in agreement with all experimental data is proposed.

Studies on the 4-carbon precursor in the biosynthesis of riboflavin. Purification and properties of L-3,4-dihydroxy-2-butanone-4-phosphate synthase

The formation of the riboflavin precursor, 6,7-dimethyl-8-ribityllumazine, from 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione requires a phosphorylated 4-carbon intermediate which has been designated as Compound X (Neuberger, G., and Bacher, A. (1985) Biochem. Biophys. Res. Commun. 127, 175-181). The enzyme catalyzing the formation of Compound X has been purified about 600-fold from the cell extract of the flavinogenic yeast Candida guilliermondii by chromatographic procedures. The purified protein appeared homogeneous as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and consisted of a single polypeptide of 24 kDa. The committed substrate of the enzyme was identified as D-ribulose 5-phosphate. The enzyme yields two products which were identified as L-3,4-dihydroxy-2-butanone 4-phosphate and formate by NMR and CD spectroscopy. Mg2+ is required for activity.

An antisense transcript from the Xenopus laevis bFGF gene coding for an evolutionarily conserved 24 kd protein

Screening of a Xenopus laevis oocyte cDNA library with a rat basic fibroblast growth factor (bFGF) cDNA led to the isolation of a 1.35 kb sequence containing exon III of the bFGF gene. Reverse complementary listing of this sequence revealed a polyadenylated transcript with an open reading frame coding for an unknown protein of mol. wt 24,292 daltons. The coding part of bFGF exon III is located in this putative mRNA in opposite direction within the 3' untranslated region. By hybridization studies on transcription orientation with single-stranded probes it could be proven that this transcript actually represents an antisense transcript to part of the Xenopus bFGF gene. Sequence organization on corresponding genomic fragments revealed that it is processed from a larger precursor by splicing mechanisms. Sequence comparison with elongated transcripts from the bFGF gene in human hepatoma has shown that the gene coding for the antisense mRNA is evolutionarily conserved.