Executive functioning following surgery near the frontal aslant tract in low-grade glioma patients: A patient-specific tractography study

BACKGROUND

The Frontal Aslant Tract (FAT) has been associated with executive functions (EF), but it remains unclear what role the FAT plays in EF, and whether preoperative dysfunction of the FAT is associated to long-lasting postsurgical executive impairments.

METHODS

In this study, we examined the course of EF from pre-surgery (n = 75) to 3 (n = 61) and 12 (n = 25) months after surgery in patients with frontal and parietal low-grade gliomas (LGGs), to establish the degree to which long-term EF deficits exist. Secondly, we used patient-specific tractography to investigate the extent to which overlap of the tumor with the FAT, as well as integrity of the FAT, presurgery were related to EF on the short and longer term after surgery.

RESULTS

LGG patients performed worse than healthy controls on all EF tests before and 3 months postsurgery. Whereas performances on three out of the four tests had normalized 1 year postsurgery (n = 26), performance on the cognitive flexibility test remained significantly worse than in healthy controls. Patients in whom the tumor overlapped with the core of the right FAT performed worse presurgery on three of the EF tests compared to those in whom the tumor did not overlap with the right FAT. Presurgical right FAT integrity was not related to presurgical EF, but only to postsurgical EF (from pre-to 3 months postsurgery). Longitudinal analyses demonstrated that patients with right (but not left) FAT core overlap performed on average worse over the pre- and postsurgical timepoints on the cognitive flexibility test.

CONCLUSIONS

We emphasized that LGG patients perform worse than healthy controls on the EF tests, which normalizes 1-year postsurgery except for cognitive flexibility. Importantly, in patients with right hemispheric tumors, tumor involvement of the FAT was associated with worse pre- and 3- months postsurgical performance, specifically concerning cognitive flexibility.

P11.56.A Shared and personalized decision-making in pre-surgical consultations of brain tumor patients and neurosurgeons

Background

In order to assess whether the oncological benefits outweigh the functional risks of treatment for an individual patient, it is important that physicians involve patients in decision-making and personalize the process. This is especially important for brain tumor patients considering the limited treatment options available. The aim of this study is to evaluate shared decision-making and the personalization of the decision-making process during consultations of brain tumor patients and their neurosurgeons.

Material and Methods

For this observational study we collected 66 audio-recordings of pre-surgical consultations of adult brain tumor patients (glioma, meningioma) and their neurosurgeons. A preliminary analysis based on a shared decision-making template was conducted on 14/66 transcribed audio-recordings to assess in how many consultations the following key elements of shared decision-making were present, namely 1) offering a choice to the patient and emphasizing that the patient’s perspective is important in making the decision, 2) discussing treatment options with benefits and risks and 3) asking about treatment preferences and personal goals. Next, thematic analysis will be performed by two independent researchers until data saturation is reached to gain insight into personalization of the decision-making process as an integral part of shared decision-making.

Results

Preliminary findings show that 1) offering the patient a choice and emphasizing that the perspective of the patient is important in decisions was done in 12/14 consultations; 2) discussing treatment options with benefits and risks was present in every consultation (14/14); and 3) in 12/14 consultations the neurosurgeon asked the patient about his or her treatment preference. However, explicitly asking the patient about personal goals occurred only in 3/14 consultations. By the time of the conference, we expect to have explored the decision-making process more in-depth and will be able to share the themes we have identified related to personalization of the decision-making process.

Conclusion

Key elements of shared decision-making were present in most pre-surgical consultations, except for asking patients about their personal goals. Discussing personal goals that patients have concerning daily life may facilitate personalization of the decision-making process.

P18.08.B Fully automatic meningioma segmentation using T1-weighted contrast-enhanced MR images only

Background

Manual segmentation of brain tumors requires expertise, is time-consuming, and is subject to inter-rater variability. Fully automatic brain tumor segmentation is possible for glioma and meningioma when volumetric T1, T1 contrast-enhanced (T1c), T2, and Fluid-attenuated inversion recovery (FLAIR) MRIs are available. In clinical care of meningiomas, however, often only volumetric T1c scans are available. In this work, we trained a deep learning network to segment meningiomas using only T1c scans for use in clinical research.

Material and Methods

NnU-Net, a deep learning model that is optimized for medical image segmentation, was trained to segment meningiomas from T1c images. This was performed on a large clinically collected meningioma dataset (n=374) of T1c scans with semi-automatically generated enhancing tumor masks and additional data from the BraTS2020 glioma dataset. Model performance was compared against inter-rater reliability, between different models, between anatomical tumor locations, and against models using multiple MRI modalities.

Results

The best performing model obtained a Dice score of 0.90. This performance was 0.03 points lower when compared to inter-rater reliability (Dice=0.93) and almost equal to models using multiple MRI modalities. Model performance split over anatomical tumor locations was between 0.90 and 0.97 (Dice).

Conclusion

Fully automatic meningioma segmentation using only T1c images is possible with an accuracy that is similar to inter-rater reliability and models using multiple imaging modalities.

P08.07.A Long-term multidimensional assessment of fatigue and fatigue as predictor of survival in patients with brain metastases after Gamma Knife radiosurgery

Background

The aim of this study was to assess long-term multidimensional fatigue and (change in) fatigue as predictor for survival in patients with brain metastases (BM) up to 21 months after Gamma Knife radiosurgery (GKRS).

Material and Methods

Patients with 1 to 10 BM, expected survival >3 months, and Karnofsky Performance Status ≥70 were included. Fatigue was measured with the Multidimensional Fatigue Inventory (MFI). Linear mixed models were used to evaluate fatigue up to 21 months after GKRS. Fatigue before GKRS and changes in fatigue in the first three months after GKRS were evaluated as predictors for survival duration.

Results

Patients with BM experienced significantly higher levels of fatigue on all subscales prior to GKRS (n=92) compared to Dutch controls (n=104), all p’s≤.001. Over 21 months, levels of physical fatigue increased significantly (p=.001), and levels of mental fatigue decreased significantly (p=.004). Between pre-GKRS and 3 months, there was a significant increase in levels of general (p<.001) and physical fatigue (p<.001), followed by stable fatigue scores between 3 (n=67) and 6 (n=53) months, 6 and 12 (n=34) months and 12 and 21 (n=21) months. Minimal clinically important (MCI) increases in general (p=.023, time ratio=0.61) and in physical fatigue (p=.008, time ratio=0.56) from pre-GKRS to 3 months thereafter were independent negative predictors of survival time (i.e., an MCI increase in these domains predicted a reduction of 39% and 44% respectively in survival time compared to stable or decreased fatigue).

Conclusion

Results indicate that up to 21 months after GKRS fatigue is a persistent problem in patients with BM. Except for an increase in general and physical fatigue up to 3 months after treatment, fatigue remained stable up to 21 months after GKRS. In addition, an MCI increase in general or physical fatigue within three months after GKRS may be related to worse survival outcome.

P01.03.B A quantitative comparison of cognitive performance and patient-reported symptoms in preoperative lower-grade glioma patients from two Dutch Hospitals

Background

Protocols for assessment of (neuro)psychological outcomes in lower-grade glioma patients vary between hospitals. This potentially complicates generalization of these outcomes. We compared standardized scores on tests of two frequently impaired cognitive domains (attention and executive functioning (EF)), and two relevant patient-reported outcomes (PROs; depression and fatigue) of two neuro-oncological hospitals that use different measurement instruments.

Material and Methods

Data were used from preoperative assessments of patients with (IDH-mut) WHO grade II/III glioma tested between 2007 and 2021 at Amsterdam UMC (AMS) or at Elisabeth-Tweesteden Hospital Tilburg (ETZ). AMS patients were referred for (neuro)psychological assessment based on physician and patient preference (paper and pencil tests), whereas all ETZ patients routinely undergo screening (computerized tests). To compare scores of the different attention and EF tests we converted patients’ performances to z-scores based on normative data. For cognitive performance, we compared scores of different cognitive flexibility tests (CST vs SAT), processing speed tests (SDC vs LDMT), and Stroop tests (Stroop I and Stroop III). PROs included the CES-D vs HADS-D and the CIS-fatigue vs MVI-general fatigue (AMS vs ETZ, resp.). Differences were tested using Fisher's, χ 2, and Mann-Whitney U tests.

Results

Assessments were done median 4 weeks (AMS, n=97, range 19-0 weeks) and 1 day (ETZ, n=106; range 14-0 days) preoperatively. Age, sex, tumor location and histology were comparable between cohorts (p>0.05), but the AMS cohort showed significantly more grade III tumors (36% vs 16%) and more awake surgeries (84% vs 46%). Z-scores measuring attention and EF (n=94 and n=95, AMS vs ETZ) were not significantly different (CST vs SAT, percentage with a disorder (z <-1.5SD) 15% vs 13%; SDC vs LDMT 13% vs 14%; Stroop I 11% vs 18%; Stroop III 13% vs 16% at AMS and ETZ, resp.). Percentages of patients with possible depression (CES-D≥16, n=88 and HADS-D≥8, n=106) did not differ significantly between hospitals (28% vs 26%), nor did percentages of patients with severe fatigue (CIS-fatigue≥35, n=88 and MVI-general fatigue (z <-1.5SD), n=38, 42% vs 24% at AMS and ETZ, resp.).

Conclusion

Standardized scores of glioma patients on cognitive domains (attention and EF) and PROs (depression and fatigue) did not differ between two centers with slightly different samples using different testing protocols. This cautiously suggests that study findings on cognitive functioning and symptoms could be generalized. For research purposes, conjoint use of pooled populations for outcome evaluation could be explored with different samples from other centers using different instruments.

Structure and receptor recognition by the Lassa virus spike complex

Lassa virus (LASV) is a human pathogen, causing substantial morbidity and mortality^1,2. Similar to other Arenaviridae, it presents a class-I spike complex on its surface that facilitates cell entry. The virus's cellular receptor is matriglycan, a linear carbohydrate that is present on α-dystroglycan^3,4, but the molecular mechanism that LASV uses to recognize this glycan is unknown. In addition, LASV and other arenaviruses have a unique signal peptide that forms an integral and functionally important part of the mature spike^5-8; yet the structure, function and topology of the signal peptide in the membrane remain uncertain^9-11. Here we solve the structure of a complete native LASV spike complex, finding that the signal peptide crosses the membrane once and that its amino terminus is located in the extracellular region. Together with a double-sided domain-switching mechanism, the signal peptide helps to stabilize the spike complex in its native conformation. This structure reveals that the LASV spike complex is preloaded with matriglycan, suggesting the mechanism of binding and rationalizing receptor recognition by α-dystroglycan-tropic arenaviruses. This discovery further informs us about the mechanism of viral egress and may facilitate the rational design of novel therapeutics that exploit this binding site.

Implementation study of the 2021 German guideline for diagnosis and treatment of multiple sclerosis

BACKGROUND

In May 2021, a new guideline on the diagnosis and treatment of multiple sclerosis and related disorders was released in Germany. Since the success of a guideline depends on how it integrates into everyday clinical practice, the German Society for Neurology (DGN) has launched a multimethod implementation project. Here we report on the results based on the consultation version of the guideline.

METHODS

We used qualitative and quantitative data analyses to capture the nature and extent of barriers and facilitating factors to the implementation. We centered on the guideline's chapter A on diagnosis, relapse therapy, and immunotherapy of multiple sclerosis. We performed nine online focus group discussions and a web-based survey and analyzed emails and letters with comments from stakeholders and independent parties that were sent spontaneously or by invitation.

RESULTS

94 neurologists answered the survey, and ≥70% agreed with the recommendations of the guideline on each major content topic. Barriers to implementation were detected in group discussions and written input. The most controversial issues of the guideline were "early treatment", "criteria for starting or switching therapy", "stepwise escalation versus early aggressive treatment", "classification of drugs into three categories of efficacy" and the scenarios on "treatment cessation". Some appreciated the highly structured recommendations, but others felt that the guideline restricts the free choice of therapy, or they were afraid of recourse claims. Some considered the guideline as too cautious regarding treatment initiation, possibly delaying necessary therapies. Others appreciated that conflicts of interests of the guideline's authoring group were minimized and thought that the new guideline is clearer, more extensive and practical.

CONCLUSION

In contrast to the survey, feedback in the focus group discussions and from individuals was diverse and sometimes more critical. Based on the overall feedback rate of about 250 people in relation to the number of 6500 board-certified neurologists in Germany, the overall appreciation of the guideline can only be considered as an indicator and not proof of acceptance. Results of this analysis were incorporated into several adjustments to the final guideline of 2021. Since the guideline is to be updated regularly under the auspices of a "living guideline", active interaction with users will continue to matter and help to improve it.

Dissociation of microdissected mouse brain tissue for artifact free single-cell RNA sequencing

Single-cell RNA sequencing (scRNA-seq) provides the transcriptome of individual cells and addresses previously intractable problems including the central nervous system’s transcriptional responses during health and disease. However, dissociating brain cells is challenging and induces artificial transcriptional responses. Here, we describe an enzymatic dissociation method for mouse brain that prevents dissociation artifacts and lowers technical variations with standardized steps. We tested this protocol on microdissected brain tissue of 3-week- to 24-month-old mice and obtained high-quality scRNA-seq results.

For complete details on the use and execution of this protocol, please refer to Safaiyan et al. (2021).

•

An optimized protocol to obtain artifact-free scRNA-seq from mouse brain tissue

•

Prevention of dissociation artifacts by blocking transcription

•

Standardized steps lower technical variations in droplet- or plate-based scRNA-seq

AB0067 RHEUMATOID ARTHRITIS IS DRIVEN NOT ONLY BY INFLAMMATION BUT ALSO BY FIBROGENESIS

Background:

Rheumatoid arthritis (RA) is a chronic, autoimmune disease characterized by inflammation of the synovium, cartilage and bone leading to joint swelling, tenderness, and dysfunction. The destruction of the joint tissue involves degradation of the extracellular matrix (ECM). The ECM consist of collagens and other connective proteins1. Studies have shown that elevated levels of collagen metabolites, such as those of type I, II, III and VI, are highly elevated in RA, correlated to disease activity and modulated in response to, for example tocilizumab2, baricitinib3 and methotrexate4. However, little is known about the formation of collagen, fibroblast activity, the fibrotic component of RA and how this influence likelihood of response to treatment.

Objectives:

We investigated the level of active fibrogenesis in a population of moderate to severe RA patients (in contrast healthy controls) by assessing blood-levels of PRO-C3 and PRO-C6 (type III and VI collagen formation markers), which have been reported to be associated with the degree and extent of fibrosis5.

Methods:

PRO-C3 and PRO-C6 was measured in serum of 166 RA patients (age; 54 (20-82), 83 % females, 91% white) at baseline and week 16 after treatment with an anti-IL6 receptor antibody in combination with MTX, as well as in serum of 77 donors (age; 42 (20-69), 51 % females, 66% white). Marker data was LN transformed. A general linear model was used when comparing groups.

Results:

The serum fibrogenesis marker PRO-C3, but not PRO-C6, was significantly elevated in RA compared to donors (2.1 vs. 2.4 ≈ 30% difference, p<0.0001, fig. 1A). None of the markers were correlated with disease measures such as DAS28, CRP, VASpain. None of the markers were modulated significantly in response to treatment. Interestingly, PRO-C3 levels were significantly higher at in non-responders (resp.) at week 16 compared to resp. (2.8 vs. 2.4 ≈ 40% difference, p=0.0018, fig. 1C). Similar trend was observed for PRO-C6 (2.2 vs. 2.0 ≈ 20% difference, p=0.061 fig. 1D).

Conclusion:

Active fibrosis, with activated fibroblasts, may play an unseen role in RA. Patients will elevated levels of the fibrosis markers PRO-C3 and PRO-C6 were less likely to respond to an anti-IL6R. This may also give clue why such treatment are less efficacious in diseases with a clear fibrotic component.

References:

[1]Karsdal et al. Rheumatoid arthritis: A case for personalized health care? ACR 2014; 66: 1273–80.

[2]Bay-Jensen et al. Effect of tocilizumab combined with methotrexate on circulating biomarkers of synovium, cartilage, and bone in the LITHE study. SAR 2014; 43: 470–8.

[3]Thudium et al. The Janus kinase 1/2 inhibitor baricitinib reduces biomarkers of joint destruction in moderate to severe rheumatoid arthritis. ART 2020; 22.

[4]Drobinski et al. Connective tissue remodeling is differently modulated by tocilizumab versus methotrexate monotherapy in patients with early rheumatoid arthritis: the AMBITION study. ART 2021; 23.

[5]Karsdal et al. Profiling and targeting connective tissue remodeling in autoimmunity - A novel paradigm for diagnosing and treating chronic diseases. AutoRev 2021; 20.

Disclosure of Interests:

None declared

Sorting Beef Subprimals by Ribeye Size at the Packer Level to Maximize Utility and Product Uniformity in Foodservice and Retail Sectors

ObjectivesTo determine the impact of sorting beef carcasses at the packer level by ribeye area, instead of sorting subprimals by weight, to provide more consistent products for the end user via foodservice and retail channelsMaterials and MethodsInstrument grading technology was used to select 100 USDA Choice, yield grade 2 or 3 sides, and 100 USDA Select, yield grade 2 or 3 sides. Carcass sides were sorted into one of five ribeye area (REA) categories, as outlined in Tabsle 6.USDA Choice carcass sides were fabricated to remove beef rib, ribeye, lip-on (IMPS 112A) and beef loin, strip loin, boneless (IMPS 180) from each USDA Choice. Beef loin, tenderloin, full, side muscle on, partially defatted (IMPS 189B) subprimals were procured from each USDA Select side. Subprimals were weighed, trimmed to specification, and passed through a 3-D visual analysis portioning machine and to obtain scan data for a variety of portioning outcomes generated by simulation software.ResultsBased on input from our foodservice collaborators, 1.25 inches (3.18 cm) was identified, for ribeye and strip loin steaks, as the targeted optimal thickness to meet consumer expectations. After evaluation of multiple portioning outcomes, it was determined that a 14.00-ounce (396.89 g) portion, for each REA category, most consistently delivered the preferred steak thickness identified previously. REA categories 1 and 2 most frequently produced desirable thickness and portion weight outcomes in ribeye and strip loin steaks. Statistical analysis of number of portions per subprimal stratified by portion weight and portion thickness revealed differences (P < 0.05) across all REA area categories in both ribeyes and strip loins. As portion weight and thickness increased, steak portion number tended to decrease. In tenderloins, an optimal steak thickness of 1.75 to 2.00 in (4.45 to 5.08 cm) was identified as optimal. Most frequently, 8, 9, and 10-ounce (226.80, 255.15, and 283.50 g) portions met the targets for optimal portion weight and thickness parameters. For tenderloins, number of portions by portion weight showed significant differences (P < 0.05) in all ribeye area categories with the exception of 7-ounces (198.45 g) and showed no differences when stratified by portion thickness. In this investigation, USDA Choice carcasses (r = 0.76) and USDA Select carcasses (r = 0.56) expressed moderate correlation between REA area and hot carcass weight.ConclusionResults of the present study suggest strip loin, ribeye, and tenderloin subprimals from carcasses possessing a ribeye area ranging from 74.8 cm2 to 87.1 cm2 offered the greatest level of utility when portioned for use in foodservice and retail sectors. Further research is warranted to continue examining the merit of sorting carcasses by ribeye area at the packer level, but results of this study suggest that there is potential for improved consistency and utility of subprimals in the foodservice and retail sectors.Table 6.Ribeye area (REA) categories and associated acceptable REA ranges.

Using the theory of planned behaviour to model antecedents of surgical checklist use: a cross-sectional study

BACKGROUND

Compliance with surgical checklist use remains an obstacle in the context of checklist implementation programs. The theory of planned behaviour was applied to analyse attitudes, perceived behaviour control, and norms as psychological antecedents of individuals' intentions to use the checklist.

METHODS

A cross-sectional survey study with staff (N = 866) of 10 Swiss hospitals was conducted in German and French. Group mean differences between individuals with and without managerial function were computed. Structural equation modelling and confirmatory factor analysis was applied to investigate the structural relation between attitudes, perceived behaviour control, norms, and intentions.

RESULTS

Significant mean differences in favour of individuals with managerial function emerged for norms, perceived behavioural control, and intentions, but not for attitudes. Attitudes and perceived behavioural control had a significant direct effect on intentions whereas norms had not.

CONCLUSIONS

Individuals with managerial function exhibit stronger perceived behavioural control, stronger norms, and stronger intentions. This could be applied in facilitating checklist implementation. The structural model of the theory of planned behaviour remains stable across groups, indicating a valid model to describe antecedents of intentions in the context of surgical checklist implementation.

Safety climate in Swiss hospital units: Swiss version of the Safety Climate Survey

RATIONALE, AIMS AND OBJECTIVES

Safety climate measurements are a broadly used element of improvement initiatives. In order to provide a sound and easy-to-administer instrument for the use in Swiss hospitals, we translated the Safety Climate Survey into German and French.

METHODS

After translating the Safety Climate Survey into French and German, a cross-sectional survey study was conducted with health care professionals (HCPs) in operating room (OR) teams and on OR-related wards in 10 Swiss hospitals. Validity of the instrument was examined by means of Cronbach's alpha and missing rates of the single items. Item-descriptive statistics group differences and percentage of 'problematic responses' (PPR) were calculated.

RESULTS

3153 HCPs completed the survey (response rate: 63.4%). 1308 individuals were excluded from the analyses because of a profession other than doctor or nurse or invalid answers (n = 1845; nurses = 1321, doctors = 523). Internal consistency of the translated Safety Climate Survey was good (Cronbach's alpha German  = 0.86; Cronbach's alpha French  = 0.84). Missing rates at item level were rather low (0.23-4.3%). We found significant group differences in safety climate values regarding profession, managerial function, work area and time spent in direct patient care. At item level, 14 out of 21 items showed a PPR higher than 10%.

CONCLUSIONS

Results indicate that the French and German translations of the Safety Climate Survey might be a useful measurement instrument for safety climate in Swiss hospital units. Analyses at item level allow for differentiating facets of safety climate into more positive and critical safety climate aspects.

Frequency of and predictors for withholding patient safety concerns among oncology staff: a survey study

Speaking up about patient safety is vital to avoid errors reaching the patient and to improve a culture of safety. This study investigated the prevalence of non-speaking up despite concerns for safety and aimed to identify predictors for withholding voice among healthcare professionals (HCPs) in oncology. A self-administered questionnaire assessed safety concerns, speaking up beliefs and behaviours among nurses and doctors from nine oncology departments. Multiple regression analysis was used to identify predictors for withholding safety concerns. A total of 1013 HCPs returned the completed survey (response rate 65%). Safety concerns were common among responders. Fifty-four per cent reported to recognise their colleagues making potentially harmful errors at least sometimes. A majority of responders reported at least some episodes of withholding concerns about patient safety. Thirty-seven per cent said they remained silent at least once when they had information that might have helped prevent an incident. Respondents believed that a high level of interpersonal, communication and coping skills are necessary to speak up about patient safety issues at their workplace. Higher levels of perceived advocacy for patient safety and psychological safety significantly decreased the frequency of withholding voice. Remaining silent about safety concerns is a common phenomenon in oncology. Improved strategies are needed to support staff in effective communication and make cancer care safer.

Silence that can be dangerous: a vignette study to assess healthcare professionals' likelihood of speaking up about safety concerns

Purpose

To investigate the likelihood of speaking up about patient safety in oncology and to clarify the effect of clinical and situational context factors on the likelihood of voicing concerns.

Patients and Methods

1013 nurses and doctors in oncology rated four clinical vignettes describing coworkers’ errors and rule violations in a self-administered factorial survey (65% response rate). Multiple regression analysis was used to model the likelihood of speaking up as outcome of vignette attributes, responder’s evaluations of the situation and personal characteristics.

Results

Respondents reported a high likelihood of speaking up about patient safety but the variation between and within types of errors and rule violations was substantial. Staff without managerial function provided significantly higher levels of decision difficulty and discomfort to speak up. Based on the information presented in the vignettes, 74%−96% would speak up towards a supervisor failing to check a prescription, 45%−81% would point a coworker to a missed hand disinfection, 82%−94% would speak up towards nurses who violate a safety rule in medication preparation, and 59%−92% would question a doctor violating a safety rule in lumbar puncture. Several vignette attributes predicted the likelihood of speaking up. Perceived potential harm, anticipated discomfort, and decision difficulty were significant predictors of the likelihood of speaking up.

Conclusions

Clinicians’ willingness to speak up about patient safety is considerably affected by contextual factors. Physicians and nurses without managerial function report substantial discomfort with speaking up. Oncology departments should provide staff with clear guidance and trainings on when and how to voice safety concerns.

Trade-offs between voice and silence: a qualitative exploration of oncology staff's decisions to speak up about safety concerns

Background

Research suggests that “silence”, i.e., not voicing safety concerns, is common among health care professionals (HCPs). Speaking up about patient safety is vital to avoid errors reaching the patient and thus to prevent harm and also to improve a culture of teamwork and safety. The aim of our study was to explore factors that affect oncology staff’s decision to voice safety concerns or to remain silent and to describe the trade-offs they make.

Methods

In a qualitative interview study with 32 doctors and nurses from 7 oncology units we investigated motivations and barriers to speaking up towards co-workers and supervisors. An inductive thematic content analysis framework was applied to the transcripts. Based on the individual experiences of participants, we conceptualize the choice to voice concerns and the trade-offs involved.

Results

Preventing patients from serious harm constitutes a strong motivation to speaking up but competes with anticipated negative outcomes. Decisions whether and how to voice concerns involved complex considerations and trade-offs. Many respondents reflected on whether the level of risk for a patient “justifies” the costs of speaking up. Various barriers for voicing concerns were reported, e.g., damaging relationships. Contextual factors, such as the presence of patients and co-workers in the alarming situation, affect the likelihood of anticipated negative outcomes. Speaking up to well-known co-workers was described as considerably easier whereas “not knowing the actor well” increases risks and potential costs of speaking up.

Conclusions

While doctors and nurses felt strong obligation to prevent errors reaching individual patients, they were not engaged in voicing concerns beyond this immediacy. Our results offer in-depth insight into fears and conditions conducive of silence and voicing and can be used for educational interventions and leader reinforcement.

'Saying it without words': a qualitative study of oncology staff's experiences with speaking up about safety concerns

OBJECTIVES

To explore the experiences of oncology staff with communicating safety concerns and to examine situational factors and motivations surrounding the decision whether and how to speak up using semistructured interviews.

SETTING

7 oncology departments of six hospitals in Switzerland.

PARTICIPANTS

Diverse sample of 32 experienced oncology healthcare professionals.

RESULTS

Nurses and doctors commonly experience situations which raise their concerns and require questioning, clarifying and correcting. Participants often used non-verbal communication to signal safety concerns. Speaking-up behaviour was strongly related to a clinical safety issue. Most episodes of 'silence' were connected to hygiene, isolation and invasive procedures. In contrast, there seemed to exist a strong culture to communicate questions, doubts and concerns relating to medication. Nearly all interviewees were concerned with 'how' to say it and in particular those of lower hierarchical status reflected on deliberate 'voicing tactics'.

CONCLUSIONS

Our results indicate a widely accepted culture to discuss any concerns relating to medication safety while other issues are more difficult to voice. Clinicians devote considerable efforts to evaluate the situation and sensitively decide whether and how to speak up. Our results can serve as a starting point to develop a shared understanding of risks and appropriate communication of safety concerns among staff in oncology.

[Patient safety in general practice]

INTRODUCTION

So far, there has been a lack of systematic data regarding critical incidents and safety climate in Swiss primary care offices. Therefore, a survey was conducted amongst physicians and nurses ("MPA") working in Swiss German primary care offices leading to a subsequent project on the telephone triage.

METHODS

Using a standardised questionnaire, healthcare professionals in primary care offices have been surveyed to determine safety risks and safety climate in their offices. The questionnaire consisted of safety-climate items as well as descriptions of 23 safety incidents. These incidents were rated in terms of frequency (appearance in the office during the past 12 months) and severity (harm associated with the last occurrence in the office). In addition, physicians and nurses answered an open-ended question referring to patient safety risks they would wish to eliminate in their offices. In the subsequent project, interviews and group discussions have been conducted with physicians and nurses in order to perform a process analysis of the telephone triage and to develop a tool that may help primary care offices to strengthen telephone triage as a secure process.

RESULTS

630 physicians and nurses (50.2% physicians, 49.8% nurses) participated in the study. 30% of the physicians and 17% of the nurses observed at least one of the 23 incidents in their offices on a daily or weekly basis. Errors in documentation were reported most frequently. As regards severity, the triage by nurses at the initial patient contact, errors in diagnosis, failure to monitor patients after therapeutic treatment in the office, and errors regarding the medication process were shown to be the most relevant. Most frequently participants wanted to eliminate the following risks to patient safety in their offices: medication (28% of all mentions), medical procedures in the office (11%) and telephone triage (7%). Participation in team meetings and quality circles proved to be relevant predictors of the safety climate dimension "team-based error prevention". Differences between occupational groups were found regarding safety incidents as well as safety climate.

CONCLUSION

The results of this study show the telephone triage to be a relevant area of patient safety in primary care that has not been focused on so far. In order to enhance safety of the triage process a new project was initiated. The result of the project is a triage guide for primary care offices. This guide supports physicians and nurses in a joint and critical examination of office structures and processes related to telephone triage. The systematically observed differences between occupational groups indicate that the entire office team need to be involved when analysing safety risks and taking action to improve patient safety. Only in doing so, risks can be identified comprehensively. Moreover, measures can be taken that are relevant to and supported by all healthcare professionals working in a primary care office. This approach of involving the entire team forms the basis for the guide on telephone triage.

Safety climate and its association with office type and team involvement in primary care

OBJECTIVE

To assess differences in safety climate perceptions between occupational groups and types of office organization in primary care.

METHODS

Primary care physicians and nurses working in outpatient offices were surveyed about safety climate. Explorative factor analysis was performed to determine the factorial structure. Differences in mean climate scores between staff groups and types of office were tested. Logistic regression analysis was conducted to determine predictors for a 'favorable' safety climate.

RESULTS

630 individuals returned the survey (response rate, 50%). Differences between occupational groups were observed in the means of the 'team-based error prevention'-scale (physician 4.0 vs. nurse 3.8, P < 0.001). Medical centers scored higher compared with single-handed offices and joint practices on the 'team-based error prevention'-scale (4.3 vs. 3.8 vs. 3.9, P < 0.001) but less favorable on the 'rules and risks'-scale (3.5 vs. 3.9 vs. 3.7, P < 0.001). Characteristics on the individual and office level predicted favorable 'team-based error prevention'-scores. Physicians (OR = 0.4, P = 0.01) and less experienced staff (OR 0.52, P = 0.04) were less likely to provide favorable scores. Individuals working at medical centers were more likely to provide positive scores compared with single-handed offices (OR 3.33, P = 0.001). The largest positive effect was associated with at least monthly team meetings (OR 6.2, P < 0.001) and participation in quality circles (OR 4.49, P < 0.001).

CONCLUSIONS

Results indicate that frequent quality circle participation and team meetings involving all team members are effective ways to strengthen safety climate in terms of team-based strategies and activities in error prevention.

Frequency of and harm associated with primary care safety incidents

OBJECTIVE

To assess frequency and severity of patient safety incidents in primary care.

STUDY DESIGN

Cross-sectional survey of health-care professionals in Swiss primary care offices.

METHODS

Physicians and nurses in primary care offices were surveyed about the frequency and severity of 23 safety incidents. Differences between professional groups and types of offices were analyzed. Reported incidents were classified in a matrix.

RESULTS

A total of 630 individuals (50.2% physicians, 49.8% nurses) participated. Among them, 30% of physicians (95% confidence interval [CI] 25%-35%) and 16.6% of nurses (95% CI 12%-21%) reported that at least 1 of the incidents occurred daily or weekly in their offices (c2 16.1, P <.001). On average, each responder reported a total of 92 incidents during the preceding 12 months (mean of 117 events for physicians, mean of 66 events for nurses; P <.001). Documentation failure was reported most frequently.The highest fraction of last occurrences with severe injury or death was for diagnostic errors (4.1%). Unadjusted for caseload, staff working in medical centers reported higher frequencies of several incidents. The frequency-harm matrix suggests that triage by nurse at initial contact, diagnostic errors, medication errors, failure to monitor patients after medical procedures, and test or intervention errors should be prioritized for action.

CONCLUSIONS

This study presents a supplemental approach to identification of safety threats in primary care. Many incidents occur regularly and are highly relevant for healthcare professionals' daily work.The results offer guidance on setting priorities for patient safety in primary care.

[Patient safety in outpatient care - study of Swiss primary care offices]

Knowledge of the most frequent and relevant safety problems is necessary in order to identify areas of risk in patient safety and to specify need for action. For Switzerland, there was no data available that systematically describes the type and frequency of critical incidents in outpatient care. Due to differences in primary care systems world wide, the transfer of international data to the Swiss context is of limited validity. For this reason the Patient Safety Foundation conducted a research project in cooperation with partners from primary care practice. We analysed the frequency and severity of patient safety risks in primary care offices as well as the safety climate in those practices. Results of the survey show the following areas of risk are of high relevance: medication, triage by nurse at initial contact (by phone), diagnosis as well as failures to monitor patients in the office. In addition, errors in tests and therapeutic interventions should be prioritized for future action. Several differences between professional groups could be identified regarding the perception and estimation of critical incidents as with respect to the safety climate. In conclusion, physicians and nurses should be involved when analysing risks and developing measures in order to insure high quality standards in patient care.

Communication barriers in counselling foreign-language patients in public pharmacies: threats to patient safety?

BACKGROUND

Foreign-language (FL) patients are at increased risk for adverse drug events. Evidence regarding communication barriers and the safety of pharmaceutical care of FL patients in European countries is scarce despite large migrant populations.

OBJECTIVE

To investigate Swiss public pharmacists' experiences and current practices in counselling FL patients with a focus on patient safety.

METHOD

In a cross-sectional study heads of public pharmacies in Switzerland were surveyed using an electronic questionnaire.

MAIN OUTCOME MEASURE

The survey assessed the frequency of communication barriers encountered in medication counselling of FL patients, perceptions of risks for adverse drug events, satisfaction with the quality of counselling provided to FL patients, current strategies to reduce risks, and preferences towards tools to improve safety for FL patients.

RESULTS

498 pharmacists completed the survey (43 % response rate). More than every second pharmacist reported at least weekly encounters at which they cannot provide good medication counselling to FL patients in the regional Swiss language. Ad-hoc interpreting by minors is also common at a considerable number of pharmacies (26.5 % reported at least one weekly occurrence). Approximately 10 % of pharmacies reported that they fail at least weekly to explain the essentials of drug therapy (e.g. dosing of children's medications) to FL patients. 79.8 % perceived the risk of FL patients for adverse drug events to be somewhat or much higher compared to other patients. 22.5 % of pharmacists reported being concerned at least monthly about medication safety when FL patients leave their pharmacy. However, the majority of pharmacists were satisfied with the quality of care provided to FL patients in their pharmacy [78.6 % (very) satisfied]. The main strategy used to improve counselling for FL patients was the employment of multilingual staff. Participants would use software for printing foreign-language labels (41.2 %) and multilingual package inserts (42.0 %) if these were available.

CONCLUSION

Communication barriers with FL patients are frequent in Swiss pharmacies and pharmacists perceive FL patients to be at increased risk for adverse drug events. Development and dissemination of communication tools are needed to support pharmacists in counselling of a diverse migrant population.

Threats to patient safety in the primary care office: concerns of physicians and nurses

BACKGROUND

Little is known about primary care professionals' concerns about risks to patient safety.

AIM

To identify threats to patient safety in the primary care office from the perspective of physicians and nurses.

DESIGN

Cross-sectional survey; participants were asked to name and rank threats to safety they personally were most concerned about.

SETTING

Physicians and nurses working in primary care offices in Switzerland.

METHODS

Verbatim reports were analysed under an inductive content-analysis framework. Coded threats were quantitatively analysed in terms of frequency and prioritisation. Differences between physicians and nurses were analysed.

RESULTS

Of 1260 invited individuals, 630 responded to the survey and 391 (31%) described 936 threats to patient safety. The coding system included 29 categories organised in 5 themes. Agreement of coders was good (kappa = 0.87, CI = 0.86-0.87). Safety of medication (8.8%), triage by nurses (7.2%) and drug interactions (6.8%) were the threats cited most frequently. Errors in diagnosis (OR = 0.21, CI 0.09-0.47, p <0.001), drug interactions (OR = 0.10, CI 0.04-0.25, p <0.001) and compliance of patients (OR = 0.28, CI 0.08-0.96, p = 0.044) were more likely to be cited by physicians. X-rays (OR = 3.34, CI 1.04-10.71, p = 0.043), confusion of patients or records (OR = 3.28, CI 1.55-6.94, p = 0.002), hygiene (OR = 3.21, CI1.12-9.19, p = 0.030), safety of office rooms (OR = 6.70, CI 1.46-30.73, p = 0.014), and confidentiality (OR = 7.38, CI 1.63-33.50, p = 0.010) were more likely to be described by nurses.

CONCLUSION

Physicians and nurses are concerned about diverse threats to patient safety in primary care. Involving both groups in detection and analysis of risks in medical offices seems a valuable strategy to improve collaboration and safety.

A randomized trial on the efficacy of methylphenidate and modafinil for improving cognitive functioning and symptoms in patients with a primary brain tumor

Limited research is available regarding the efficacy of psychostimulants in treating cognitive function in primary brain tumor patients. An open-label, randomized, pilot trial examined both the general and differential efficacy of 4 weeks of methylphenidate (MPH) and modafinil (MOD) in 24 brain tumor patients. Participants completed cognitive tests and self-report measures of fatigue, sleep disturbance, mood and quality of life at baseline and after 4 weeks.Following stimulant treatment, there was evidence of a beneficial effect on test performance in speed of processing and executive function requiring divided attention. Patients with the greatest deficit in executive function at baseline appeared to derive the greatest benefit following stimulant therapy. Inconsistent, differential effects were found on a measure of attention in favor of MPH and on a measure of processing speed in favor of MOD. There was also evidence of a general beneficial effect on patient-reported measures of fatigue, mood, and quality of life, with no statistically significant differences between treatment arms in these measures over time. The results from this small pilot study should be interpreted with caution, but appear to warrant additional research, in larger study samples, targeting fatigue, processing speed and executive function, and exploring different doses of stimulants. Future studies may also wish to explore the specific patient factors that may be associated with responsiveness to psychostimulant treatment.

A description of a cognitive rehabilitation programme evaluated in brain tumour patients with mild to moderate cognitive deficits

This series of articles for rehabilitation in practice aims to cover a knowledge element of the rehabilitation medicine curriculum. Nevertheless they are intended to be of interest to a multidisciplinary audience. The competency addressed in this article is cognitive rehabilitation.

BACKGROUND

There is a paucity of literature on the rationale, design, and content of successful cognitive rehabilitation programmes. In the current paper, we describe in detail a cognitive rehabilitation programme that has previously proven effective in a randomized controlled trial in patients with primary brain tumours. The programme's content may be of practical interest to those working with populations of cognitively impaired patients. Programme: The programme consists of six weekly, individual, 2-hour sessions plus homework, and incorporates both strategy training and attention retraining. The elements were taken from two of the few programmes that are evidence-based. It's design consists of psycho-education, teaching of strategies to compensate for problems in attention, memory and executive functioning in daily life. The retraining was based on the assumption that a target process can be improved by frequently practising exercises. It is focused on attention as intact attention may also be necessary for adequate functioning of other cognitive domains. The hierarchically organized exercises, embedded in a game-like computer program, were tailored to the needs of the individual patient.

EVALUATION

Mean total training time was estimated to be 35 hours in seven weeks. Adherence to the programme was high. The majority of the participants found the programme to be (very) useful. However, older participants found the programme more burdensome than younger patients.

DISCUSSION

Splitting up and spreading out sessions may increase the feasibility and usefulness of the programme for older participants. Further suggestions for improvements and future studies on this programme are also provided.

ERp57 and PDI: multifunctional protein disulfide isomerases with similar domain architectures but differing substrate–partner associationsThis paper is one of a selection of papers published in this Special Issue, entitled CSBMCB — Membrane Proteins in Health and Disease

Secretory proteins become folded and acquire stabilizing disulfide bonds in the endoplasmic reticulum (ER). Correct disulfide bond formation is a key step in ER quality control (ERQC). Proteins with incorrect disulfide bonds are recognized by the quality control machinery and are retrotranslocated into the cytosol where they are degraded by the proteasome. The mammalian ER contains 17 disulfide isomerases and at least one of them, ERp57, works in conjunction with the ER lectin-like chaperones calnexin and calreticulin. The targeting of ERp57 to calnexin–calreticulin is mediated by its noncatalytic b′ domain, and analogous domains in other disulfide isomerases likely determine their substrate and partner preferences. This review discusses some explanations for the multiplicity of disulfide isomerases and highlights structural differences in the b′ domains of PDI and ERp57 as an example of how noncatalytic domains define specialized roles in oxidative folding.

Molecular mechanisms in clathrin-mediated membrane budding revealed through subcellular proteomics

Subcellular proteomics is a powerful new approach that combines subcellular fractionation and MS (mass spectrometry) to identify the protein complement of cellular compartments. The approach has been applied to isolated organelles and major suborganellar structures and each study has identified known proteins not previously understood to associate with the compartment and novel proteins that had been described only as predicted open-reading frames from genome sequencing data. We have utilized subcellular proteomics to analyse the protein components of CCVs (clathrin-coated vesicles) isolated from adult brain. Accounting for identified fragmented peptides allows for a quantitative assessment of protein complexes associated with CCVs, and the identification of many of the known components of post-fusion synaptic vesicles demonstrates that a main function for brain CCVs is to recycle synaptic vesicles. In addition, we have identified a number of novel proteins that participate in CCV formation and function at the trans-Golgi network and the plasma membrane. Characterization of two of these proteins, NECAP1 and NECAP2, has led to the identification of a new consensus motif that mediates protein interactions with the clathrin adaptor protein 2. These studies highlight the ability of proteomics to reveal new insights into the mechanisms and functional roles of subcellular compartments.

Solution structure of an arabinonucleic acid (ANA)/RNA duplex in a chimeric hairpin: comparison with 2'-fluoro-ANA/RNA and DNA/RNA hybrids

Hybrids of RNA and arabinonucleic acid (ANA) as well as the 2'-fluoro-ANA analog (2'F-ANA) were recently shown to be substrates of the enzyme RNase H. Although RNase H binds to double-stranded RNA, no cleavage occurs with such duplexes. Therefore, knowledge of the structure of ANA/RNA hybrids may prove helpful in the design of future antisense oligonucleotide analogs. In this study, we have determined the NMR solution structures of ANA/RNA and DNA/RNA hairpin duplexes and compared them to the recently published structure of a 2'F-ANA/RNA hairpin duplex. We demonstrate here that the sugars of RNA nucleotides of the ANA/RNA hairpin stem adopt the C3'-endo (north, A-form) conformation, whereas those of the ANA strand adopt a 'rigid' O4'-endo (east) sugar pucker. The DNA strand of the DNA/RNA hairpin stem is flexible, but the average DNA/RNA hairpin structural parameters are close to the ANA/RNA and 2'F-ANA/RNA hairpin parameters. The minor groove width of ANA/RNA, 2'F-ANA/RNA and DNA/RNA helices is 9.0 +/- 0.5 A, a value that is intermediate between that of A- and B-form duplexes. These results rationalize the ability of ANA/RNA and 2'F-ANA/RNA hybrids to elicit RNase H activity.

NMR solution structure of an oligonucleotide hairpin with a 2'F-ANA/RNA stem: implications for RNase H specificity toward DNA/RNA hybrid duplexes

The first structure of a 2'-deoxy-2'-fluoro-D-arabinose nucleic acid (2'F-ANA)/RNA duplex is presented. We report the structural characterization by NMR spectroscopy of a small hybrid hairpin, r(GGAC)d(TTCG)2'F-a(GTCC), containing a 2'F-ANA/RNA stem and a four-residue DNA loop. Complete (1)H, (13)C, (19)F, and (31)P resonance assignments, scalar coupling constants, and NOE constraints were obtained from homonuclear and heteronuclear 2D spectra. In the chimeric duplex, the RNA strand adopts a classic A-form structure having C3' endo sugar puckers. The 2'F-ANA strand is neither A-form nor B-form and contains O4' endo sugar puckers. This contrasts strongly with the dynamic sugar conformations previously observed in the DNA strands of DNA/RNA hybrid duplexes. Structural parameters for the duplex, such as minor groove width, x-displacement, and inclination, were intermediate between those of A-form and B-form duplexes and similar to those of DNA/RNA duplexes. These results rationalize the enhanced stability of 2'F-ANA/RNA duplexes and their ability to elicit RNase H activity. The results are relevant for the design of new antisense drugs based on sugar-modified nucleic acids.

Structure and function of the C-terminal PABC domain of human poly(A)-binding protein

We have determined the solution structure of the C-terminal quarter of human poly(A)-binding protein (hPABP). The protein fragment contains a protein domain, PABC [for poly(A)-binding protein C-terminal domain], which is also found associated with the HECT family of ubiquitin ligases. By using peptides derived from PABP interacting protein (Paip) 1, Paip2, and eRF3, we show that PABC functions as a peptide binding domain. We use chemical shift perturbation analysis to identify the peptide binding site in PABC and the major elements involved in peptide recognition. From comparative sequence analysis of PABC-binding peptides, we formulate a preliminary PABC consensus sequence and identify human ataxin-2, the protein responsible for type 2 spinocerebellar ataxia (SCA2), as a potential PABC ligand.

Properties of arabinonucleic acids (ANA & 20'F-ANA): implications for the design of antisense therapeutics that invoke RNase H cleavage of RNA

Inversion of configuration of the C2' position of RNA leads to a very unique nucleic acid structure: arabinonucleic acid (ANA). ANA, and its 2'-fluoro derivative (2'F-ANA) from hybrids with RNA that are capable of activating RNase H, resulting in cleavage of the RNA strand. In this paper, we review the properties of duplexes formed between ANA (or 2'F-ANA) and its RNA complement. These studies support the notion that RNase H is sensitive to the minor groove dimensions of the hybrid substrate.

Structural proteomics of an archaeon

A set of 424 nonmembrane proteins from Methanobacterium thermoautotrophicum were cloned, expressed and purified for structural studies. Of these, approximately 20% were found to be suitable candidates for X-ray crystallographic or NMR spectroscopic analysis without further optimization of conditions, providing an estimate of the number of the most accessible structural targets in the proteome. A retrospective analysis of the experimental behavior of these proteins suggested some simple relations between sequence and solubility, implying that data bases of protein properties will be useful in optimizing high throughput strategies. Of the first 10 structures determined, several provided clues to biochemical functions that were not detectable from sequence analysis, and in many cases these putative functions could be readily confirmed by biochemical methods. This demonstrates that structural proteomics is feasible and can play a central role in functional genomics.

Design and solution structure of functional peptide mimetics of nerve growth factor

The C-D loop in nerve growth factor (NGF) is involved in binding to the NGF receptor, TrkA. It is flexible and adopts several different types conformations in different NGF crystal forms. We have previously shown that a small cyclic peptide derived from the C-D loop of NGF binds to the TrkA receptor by mimicking the structure of this loop. To understand structure-function relationships in NGF C-D loop mimetics, we have produced a series of peptides predicted to form different types of beta-turns. The peptides were tested for their ability to promote cell survival in serum-free medium and to induce TrkA tyrosine phosphorylation. NMR structural studies were used to determined the backbone conformation and the spatial orientation of side chains involved in binding to the TrkA receptor. Peptides that form type I or type gammaL-alphaR beta-turns were the most active. The variety of active loop conformations suggests that the mimetics (and NGF) accommodate the binding site on TrkA by an 'induced fit' mechanism. In agreement with this hypothesis, NMR relaxation measurements detected both fast and slow motion in the peptides. We also characterized a retro-inverso peptide derived from the NGF C-D loop. This D-amino acid cyclic peptide did not adopt a conformation homologous to the NGF C-D loop and was inactive. This may be representative of difficulties in producing structural and functional mimetics by retro-inverso schemes.

Determination of sex from femora

The determination of sex from bones or bone fragments considerably contributes to identifying unknown bodies or skeletal remains. Due to temporal change and regional differences anthropometric standards have to be constantly renewed. The present study provides measurements of femoral dimensions in a contemporary German population and analyses sexual dimorphism by discriminant analysis. Maximum length (male: 46.4+/-2.4 cm, female: 43.4+/-2.4 cm), maximum midshaft diameter (male: 3.1+/-0.2 cm, female: 2.8+/-0.2 cm), condylar width (male: 8.4+/-1.0 cm, female: 7.7+/-0.5 cm), vertical head diameter (male: 4.9+/-0.3 cm, female: 4.4+/-0.3 cm), head circumference (male: 15.7+/-0.8 cm, female: 13.8+/-1.0 cm) and transverse head diameter (male: 4.9+/-0.3 cm, female: 4.3+/-0.3 cm) were measured in 170 femora, 100 from male (age: 16-92 years, mean: 60.8 years; body height: 153-190 cm, mean: 171 cm) and 70 from female (age: 20-96 years, mean: 72 years; body height: 146-175 cm, mean: 161 cm) individuals. In the discriminant analysis (leave-one-out-method) 67.7% of cases could be grouped correctly with the maximum length alone, 72.4% with the maximum midshaft diameter, 81.4% with the condylar width, 86.8% with the vertical head diameter, 87.7% with the head circumference and 89.6% with the transverse head diameter. The stepwise procedure with all head measurements showed that the results for the transverse head diameter could not be improved. With all measurements subjected to stepwise procedure 91.7% of cases could be classified correctly combining midshaft diameter and head circumference (D=3.012xmidshaft diameter in cm+0.780xhead circumference in cm 20.569).

Conformational changes in the PBX homeodomain and C-terminal extension upon binding DNA and HOX-derived YPWM peptides

PBX is a member of the three amino acid loop extension (TALE) class of homeodomains. PBX binds DNA cooperatively with HOX homeodomain proteins that contain a conserved YPWM motif. The amino acids immediately C-terminal to the PBX homeodomain increase the affinity of the homeodomain for its DNA site and HOX proteins. We have determined the structure of the free PBX homeodomain using NMR spectroscopy. Both the PBX homeodomain and the extended PBX homeodomain make identical contacts with a 5'-TGAT-3' DNA site and a YPWM peptide. A fourth alpha-helix, which forms upon binding to DNA, stabilizes the extended PBX structure. Variations in DNA sequence selectivity of heterodimeric PBX-HOX complexes depend on the HOX partner; however, a comparison of five different HOX-derived YPWM peptides showed that each bound to PBX in the same way, differing only in the strength of the association.

Rapid fold and structure determination of the archaeal translation elongation factor 1beta from Methanobacterium thermoautotrophicum

The tertiary fold of the elongation factor, aEF-1beta, from Methanobacterium thermoautotrophicum was determined in a high-throughput fashion using a minimal set of NMR experiments. NMR secondary structure prediction, deuterium exchange experiments and the analysis of chemical shift perturbations were combined to identify the protein fold as an alpha-beta sandwich typical of many RNA binding proteins including EF-G. Following resolution of the tertiary fold, a high resolution structure of aEF-1beta was determined using heteronuclear and homonuclear NMR experiments and a semi-automated NOESY assignment strategy. Analysis of the aEF-1beta structure revealed close similarity to its human analogue, eEF-1beta. In agreement with studies on EF-Ts and human EF-1beta, a functional mechanism for nucleotide exchange is proposed wherein Phe46 on an exposed loop acts as a lever to eject GDP from the associated elongation factor G-protein, aEF-1alpha. aEF-1beta was also found to bind calcium in the groove between helix alpha2 and strand beta4. This novel feature was not observed previously and may serve a structural function related to protein stability or may play a functional role in archaeal protein translation.