Apixaban for treatment of embolic stroke of undetermined source (ATTICUS) randomized trial – update of patient characteristics and study timeline after interim analysis

Background

Secondary prevention after embolic stroke of undetermined source (ESUS) has not yet been established. ESUS is associated with high risk of recurrent ischemic stroke and clinically silent ischemic lesions. Secondary prevention with aspirin is the current standard therapy in ESUS patients, despite high prevalence of occult atrial fibrillation (AF).

Purpose

To determine whether the direct oral factor Xa inhibitor apixaban, started within 28 days after index stroke, is superior to aspirin in preventing new ischemic lesions in subjects with remote cardiac monitoring. Primary endpoint was detection of new ischemic lesions in flair and diffusion-weighted (DWI) MR imaging at 12 months follow-up.

Methods

The study enrolled ESUS patients with risk profile for cardiac thromboembolism (i.e., left atrium (LA) size >45 mm, spontaneous echo contrast in LA appendage, LA appendage flow velocity ≤0.2 cm/s, atrial high rate episodes, CHA2DS2-Vasc score ≥4, patent foramen ovale). Patients were randomized 1:1 into the aspirin and apixaban arms. Study drug was initiated within 3–28 days after minor/moderate stroke and 14–28 days after major stroke. MRI (Flair/DWI) was conducted within 7 days of AF detection by remote cardiac monitors and at 12 months. ClinicalTrials.gov Identifier: NCT02427126. Funding: The trial is supported by BMS-Pfizer Alliance.

Results

Enrollment was stopped after interims analysis (including 200 patients) due to futility. Overall, 373 patients were screened with 353 being enrolled (178 and 175 in apixaban and ASA arms, respectively). So far, 130 (73.0%) and 120 (68.6%) subjects from apixaban and ASA arms, respectively, completed the study. 2% death, 1.7% withdrawal, and 1.7% were lost to follow-up. 3.9% did not completed the study for other reasons. Mean age of the ATTICUS population was 68.5 years with 51% males. 80% of the subjects suffered from hypertension. Mean systolic blood pressure at enrollment was 132 mmHg, BMI was 27.7, and CHA2DS-VASc-Score was 4.9. So far, adverse events (AE) occurred in 63% of the subjects, 30% was documented as severe. 6.8% cases of recurrent ischemic stroke and no case of hemorrhagic stroke were reported. Only 1 case of severe bleeding was reported in the aspirin arm. Newly detected AF was reported in 80 patients (23%), 42 occurring in the aspirin arm. As required by protocol, latter were immediately switched from aspirin to apixaban. Due to ongoing data clearing, numbers and % will change until presentation.

Conclusions

In contrast to the recently published NAVIGATE and RESPECT ESUS trials, patients enrolled in ATTICUS need to exhibit additional AF predicting factors. Furthermore, mandatory cardiac remote monitoring will help to elucidate the impact of AF and the effects of early oral anticoagulation with apixaban compared to antiplatelet therapy with aspirin on the incidence of new ischemic lesions after ESUS. Preliminary data will be presented and discussed in the context of current literature.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): The trial is supported by BMS-Pfizer Alliance.

Methodology of measuring postoperative cognitive dysfunction: a systematic review

BACKGROUND

Postoperative cognitive dysfunction (POCD) is an adverse outcome that impacts patients' quality of life. Its diagnosis relies on formal cognitive testing performed before and after surgery. The substantial heterogeneity in methodology limits comparability and meta-analysis of studies. This systematic review critically appraises the methodology of studies on POCD published since the 1995 Consensus Statement and aims to provide guidance to future authors by providing recommendations that may improve comparability between future studies.

METHODS

This systematic review of literature published between 1995 and 2019 included studies that used baseline cognitive testing and a structured cognitive test battery, and had a minimal follow-up of 1 month. For cohorts with multiple publications, data from the primary publication were supplemented with available data from later follow-up studies.

RESULTS

A total of 274 unique studies were included in the analysis. In the included studies, 259 different cognitive tests were used. Studies varied considerably in timing of assessment, follow-up duration, definition of POCD, and use of control groups. Of the 274 included studies, 70 reported POCD as a dichotomous outcome at 1 to <3 months, with a pooled incidence of 2998/10 335 patients (29.0%).

CONCLUSIONS

We found an overwhelming heterogeneity in methodology used to study POCD since the publication of the 1995 Consensus Statement. Future authors could improve study quality and comparability through optimal timing of assessment, the use of commonly used cognitive tests including the Consensus Statement 'core battery', application of appropriate cut-offs and diagnostic rules, and detailed reporting of the methods used.

PROSPERO REGISTRY NUMBER

CRD42016039293.

Midlevel visual deficits after strokes involving area human V4

We present the results of 51 stroke patients with free central visual fields of which about half suffer from clear deficits of midlevel vision undetected by standard clinical tests. These patients yield significantly elevated thresholds for detection and/or discrimination between forms defined by motion, colour, or line orientation ('texture'). As demonstrated by voxel-based lesion-symptom mapping (VLSM) the underlying lesions involve mainly area human V4 (hV4) located in the posterior third of the fusiform gyrus and extending into the lingual gyrus. Patient's detection thresholds correlate only very weakly between the submodalities tested, indicating partly separate neural networks on mid-level vision for colour, motion, and texture detection. Correlations are far stronger for form discrimination tasks, indicating partly shared mechanisms for even simple form discrimination of distinct visual submodalities. We conclude that deficits of visual perception are far more common after strokes in visual brain areas than is apparent in clinical practice. Our results further clarify the functional organization of midlevel visual cortical areas.

Discount Rate Determination for Economic Evaluations in HTA in the Philippines

To inform the development of a reference case for economic evaluation, we explored various approaches to determine a base case discount rate and rate options for discounting benefits and costs.

We conducted literature review and expert consultations to list approaches to determine base case discount rates, noting the advantages and disadvantages of each approach. The same methods were used to identify whether different discount rates would be applied to costs and benefits. We computed a social rate of time preference using the Ramsey formula: rc = ρ+μg, where ρ = pure rate of time preference μ= elasticity of the marginal utility of consumption and g= growth rate in per capita income. We assumed ρ = 1%, μ = 1.4% consistent with international practice, but used actual g of the Philippines of 4.5%. We compared this with the official social discount rate and with rate most commonly used internationally. These options were presented to the Philippine Health Technology Assessment Council for decisionmaking.

Based on reviewed literature, 10 out of 22 countries used a 3.0% to 3.5% discount rate while 18 countries from the same pool applied equal discount rates for both costs and outcomes. The official social discount rate (SDR) prescribed by the Philippine National Economic Development Authority is 10% for all social investments. Upon input of the values, rc was calculated at 7%, which is above the international norm but below the official rate. Four discount rate options were identified: 3%, 3.5%, 7% and 10%.

Evidence suggested using a discount rate higher than 3% to 3.5% for low-to-middle income countries. A more conservative rate based on the Ramsey formula of 7% base case discount rate was selected in performing economic evaluations. Sensitivity analysis was set between 3% and 10% to allow benchmarking with international practice and with the official SDR, respectively. Given Philippines' early HTA implementation phase, it was agreed to subject these rates to regular review.

Key messages

Setting a discount rate in economic evaluations is a crucial process for HTA institutionalization. Discount rate determination heavily relies on decision context a country considers most relevant.

Guideline-conform translation and cultural adaptation of the Addenbrooke's Cognitive Examination III into German

Objective: Age-related disorders, such as dementia, significantly contribute to the global burden of disease. Adequate screening in the primary care setting is critical for early detection and proper management. The Addenbrooke's Cognitive Examination III (ACE-III) is an open-source neuropsychological test with superior diagnostic quality in comparison to the Mini-Mental State Examination (MMSE). Our aim was to perform a guideline-conform English-German translation and cultural adaptation of the ACE-III in order to enable implementation in German-speaking countries. Methods: The translation and cultural adaptation were performed in accordance with the "Principles of Good Practice for the Translation and Cultural Adaptation Process for Patient-Reported Outcomes (PRO) Measures" from the International Society for Pharmacoeconomics and Outcome Research (ISPOR) (Wild et al. 2005). Four separate English-German translations were compiled into one German consensus translation, which was then translated back into English and compared to the original English version. After comparison, the German consensus translation was revised with emphasis on the identified differences between the English original version and the English translated version. This revised German consensus translation was subsequently evaluated for clinical applicability on a 5-point scale (0 - not applicable; 5 - applicable without any restrictions) by 20 practitioners experienced in the field of neuropsychological testing, using an anonymized, paper-based 22-item survey. Results: Nineteen of the 20 practitioners (95.0%) rated the German ACE-III translation as overall applicable. The median rating was 4.0 [IQR (4.0/5.0)]. When evaluating survey items assessing the applicability of the individual 19 subtests of the ACE-III, all of them (100%) were rated as applicable with a median rating of 4.5 [IQR (4.1/4.9)]. Conclusion: The German ACE-III translation in its current form is generally applicable and can be utilized for clinical and scientific purposes.

Measurement of the Permanent Electric Dipole Moment of the Neutron

We present the result of an experiment to measure the electric dipole moment (EDM) of the neutron at the Paul Scherrer Institute using Ramsey's method of separated oscillating magnetic fields with ultracold neutrons. Our measurement stands in the long history of EDM experiments probing physics violating time-reversal invariance. The salient features of this experiment were the use of a ^{199}Hg comagnetometer and an array of optically pumped cesium vapor magnetometers to cancel and correct for magnetic-field changes. The statistical analysis was performed on blinded datasets by two separate groups, while the estimation of systematic effects profited from an unprecedented knowledge of the magnetic field. The measured value of the neutron EDM is d_{n}=(0.0±1.1_{stat}±0.2_{sys})×10^{-26}  e.cm.

Stability of neuropsychological test performance in older adults serving as normative controls for a study on postoperative cognitive dysfunction

OBJECTIVE

Studies of postoperative cognitive dysfunction (POCD) rely on repeat neuropsychological testing. The stability of the applied instruments, which are affected by natural variability in performance and measurement imprecision, is often unclear. We determined the stability of a neuropsychological test battery using a sample of older adults from the general population. Forty-five participants aged 65 to 89 years performed six computerized and non-computerized neuropsychological tests at baseline and again at 7 day and 3 months follow-up sessions. Mean scores on each test were compared across time points using repeated measures analyses of variance (ANOVA) with pairwise comparison. Two-way mixed effects, absolute agreement analyses of variance intra-class correlation coefficients (ICC) determined test-retest reliability.

RESULTS

All tests had moderate to excellent test-retest reliability during 7-day (ICC range 0.63 to 0.94; all p < 0.01) and 3-month intervals (ICC range 0.60 to 0.92; all p < 0.01) though confidence intervals of ICC estimates were large throughout. Practice effects apparent at 7 days eased off by 3 months. No substantial differences between computerized and non-computerized tests were observed. We conclude that the present six-test neuropsychological test battery is appropriate for use in POCD research though small sample size of our study needs to be recognized as a limitation. Trial registration ClinicalTrials.gov Identifier NCT02265263 (15th October 2014).

Delirium is associated with frequency band specific dysconnectivity in intrinsic connectivity networks: preliminary evidence from a large retrospective pilot case-control study

Background

Pathophysiological concepts in delirium are not sufficient to define objective biomarkers suited to improve clinical approaches. Advances in neuroimaging have revalued electroencephalography (EEG) as a tool to assess oscillatory network activity in neuropsychiatric disease. Yet, research in the field is limited to small populations and largely confined to postoperative delirium, which impedes generalizability of findings and planning of prospective studies in other populations. This study aimed to assess effect sizes of connectivity measures in a large mixed population to demonstrate that there are measurable EEG differences between delirium and control patients.

Methods

This retrospective pilot study investigated EEG measures as biomarkers in delirium using a case-control design including patients diagnosed with delirium (DSM-5 criteria) and age-/gender-matched controls drawn from a database of 9980 patients (n = 129 and 414, respectively). Assessors were not blinded for groups. Power spectra and connectivity estimates, using the weighted phase log index, of continuous EEG data were compared between conditions. Alterations of information flow through nodes of intrinsic connectivity networks (ICN; default mode, salience, and executive control network) were evaluated in source space using betweenness centrality. This was done frequency specific and network nodes were defined by the multimodal human cerebral cortex parcellation based on human connectome project data.

Results

Delirium and control patients exhibited distinct EEG power, connectivity, and network characteristics (F_(72,540) = 70.3, p < .001; F_(493,1079) = 2.69, p < .001; and F_(718,2159) = 1.14, p = .007, respectively). Connectivity analyses revealed global alpha and regional beta band disconnectivity that was accompanied by theta band hyperconnectivity in delirious patients. Source and network analyses yielded that these changes are not specific to single intrinsic connectivity networks but affect multiple nodes of networks engaged in level of consciousness, attention, working memory, executive control, and salience detection. Effect sizes were medium to strong in this mixed population of delirious patients.

Conclusions

We quantified effect sizes for EEG connectivity and network analyses to be expected in delirium. This study implicates that theta band hyperconnectivity and alpha band disconnectivity may be essential mechanisms in the pathophysiology of delirium. Upcoming prospective studies will build upon these results and evaluate the clinical utility of identified EEG measures as therapeutic and prognostic biomarkers.

Electronic supplementary material

The online version of this article (10.1186/s40814-018-0388-z) contains supplementary material, which is available to authorized users.

Imaging of a Metastatic Gastrointestinal Carcinoid by F-18-DOPA Positron Emission Tomography

The localization of carcinoids in the gastrointestinal tract is frequently difficult if not impossible with the imaging procedures used to date. It is reported on a patient with metastasizing carcinoid in whom various imaging procedures were not successful in detecting the primary tumor. Due to the importance of primary tumor proof for potential curative surgical therapy, a whole-body positron emission tomography with F-18-DOPA was performed. PET enabled localization of a potential primary tumor in the ileum. Moreover, in addition to the known abdominal lymph node and liver metastases, it detected a mediastinal lymph node metastasis and a pulmonary metastasis. F-18-DOPA whole-body PET may be a very promising imaging approach to the localization and staging of gastrointestinal carcinoids.

THE ROLE OF SURGERY IN A PATIENT WITH CARCINOID SYNDROME, COMPLICATED BY CARCINOID HEART DISEASE

A 55-year-old female patient was admitted for flushing and abdominal pain in the right upper quadrant. Her past medical history revealed high blood pressure and a recent echocardiography showed thickened appearance of tricuspid valve with coaptation defect and grade II tricuspid regurgitation. Contrast enhanced abdominal CT scan and MRI were subsequently performed and revealed a large macronodular liver mass, as well as other micronodular lesions disseminated in the liver parenchyma. CT guided biopsy from the main liver mass revealed neuroendocrine tumor of unknown origin (probably GI) with Ki-67 of 8%. Surgical exploration was decided. During laparotomy, the primary tumor was found in the proximal ileum and the patient underwent segmental enterectomy. Non-anatomical hepatectomy was also performed to remove the bulk of the tumor burden (more than 90%). Postoperative course was uneventful and the carcinoid syndrome relieved. At present, 15 months postoperatively, the patient is under treatment with somatostatin analogue for its antiproliferative effect, with good clinical, biochemical and tumoral control and stable heart disease. In patients with neuroendocrine liver metastases from unknown primary, surgical exploration could allow detection (and resection) of the primary tumor and surgical debulking of liver metastases to control carcinoid syndrome and carcinoid heart disease.

Mobile electronic versus paper case report forms in clinical trials: a randomized controlled trial

BACKGROUND

Regulations, study design complexity and amounts of collected and shared data in clinical trials render efficient data handling procedures inevitable. Recent research suggests that electronic data capture can be key in this context but evidence is insufficient. This randomized controlled parallel group study tested the hypothesis that time efficiency is superior when electronic (eCRF) instead of paper case report forms (pCRF) are used for data collection. We additionally investigated predictors of time saving effects and data integrity.

METHODS

This study was conducted on top of a clinical weight loss trial performed at a clinical research facility over six months. All study nurses and patients participating in the clinical trial were eligible to participate and randomly allocated to enter cross-sectional data obtained during routine visits either through pCRF or eCRF. A balanced randomization list was generated before enrolment commenced. 90 and 30 records were gathered for the time that 27 patients and 2 study nurses required to report 2025 and 2037 field values, respectively. The primary hypothesis, that eCRF use is faster than pCRF use, was tested by a two-tailed t-test. Analysis of variance and covariance were used to evaluate predictors of entry performance. Data integrity was evaluated by descriptive statistics.

RESULTS

All randomized patients were included in the study (eCRF group n = 13, pCRF group n = 14). eCRF, as compared to pCRF, data collection was associated with significant time savings  across all conditions (8.29 ± 5.15 min vs. 10.54 ± 6.98 min, p = .047). This effect was not defined by participant type, i.e. patients or study nurses (F_(1,112) = .15, p = .699), CRF length (F_(2,112) = .49, p = .609) or patient age (Beta = .09, p = .534). Additional 5.16 ± 2.83 min per CRF were saved with eCRFs due to data transcription redundancy when patients answered questionnaires directly in eCRFs. Data integrity was superior in the eCRF condition (0 versus 3 data entry errors).

CONCLUSIONS

This is the first study to prove in direct comparison that using eCRFs instead of pCRFs increases time efficiency of data collection in clinical trials, irrespective of item quantity or patient age, and improves data quality.

TRIAL REGISTRATION

Clinical Trials NCT02649907 .

Long-Lasting Enhancement of Visual Perception with Repetitive Noninvasive Transcranial Direct Current Stimulation

Understanding processes performed by an intact visual cortex as the basis for developing methods that enhance or restore visual perception is of great interest to both researchers and medical practitioners. Here, we explore whether contrast sensitivity, a main function of the primary visual cortex (V1), can be improved in healthy subjects by repetitive, noninvasive anodal transcranial direct current stimulation (tDCS). Contrast perception was measured via threshold perimetry directly before and after intervention (tDCS or sham stimulation) on each day over 5 consecutive days (24 subjects, double-blind study). tDCS improved contrast sensitivity from the second day onwards, with significant effects lasting 24 h. After the last stimulation on day 5, the anodal group showed a significantly greater improvement in contrast perception than the sham group (23 vs. 5%). We found significant long-term effects in only the central 2–4° of the visual field 4 weeks after the last stimulation. We suspect a combination of two factors contributes to these lasting effects. First, the V1 area that represents the central retina was located closer to the polarization electrode, resulting in higher current density. Second, the central visual field is represented by a larger cortical area relative to the peripheral visual field (cortical magnification). This is the first study showing that tDCS over V1 enhances contrast perception in healthy subjects for several weeks. This study contributes to the investigation of the causal relationship between the external modulation of neuronal membrane potential and behavior (in our case, visual perception). Because the vast majority of human studies only show temporary effects after single tDCS sessions targeting the visual system, our study underpins the potential for lasting effects of repetitive tDCS-induced modulation of neuronal excitability.

ROBOTIC SURGERY IN THE ROMANIAN HEALTH SYSTEM

Robotic surgery appeared in the Romanian health system in 2008 with the purchase of the first twosurgical robots. One of them belonged to “Dan Setlacec” Center of General Surgery and LiverTransplantation - Fundeni and the second to Floreasca Emergency Clinical Hospital. Funding wasprovided by the Ministry of Health special program. Since the first year of operation by the roboticsystem, the Fundeni Center has performed about 200 interventions. A key objective of the programwas to identify the interventions that are cost efficient, i.e., around 9,000 RON for each surgicalintervention. Subsequently, another 7 robotic systems were put into operation, out of which threeare in urology and four in general surgery. Given the high cost of consumables and post-warrantymaintenance, the operation of these robotic systems could only be done through the national healthsystem, or private sector. The operation of the program allowed for an annual limited number ofcases, and since 2013 the program funding has ceased. During this period, a significant experiencewas gained using robotic surgery in general surgery, urology and gynecology as well.

Complex histopathological and surgical aspects in a case of giant malignant gastric perforation

We present the case of a 52-year-old male patient, hospitalized on an emergency basis in the University Emergency Hospital in Bucharest, after being diagnosed with pneumoperitoneum acute abdomen, for which emergency surgery was mandatory. A 3,5-4 cm malignant gastric perforation, ascitis and peritoneal carcinomatosis were found. The histopathological exam revealed infiltrative mucinous gastric carcinoma with epiploic metastasis. Due to the lack of available gastric material, an atypical surgical solution was performed: gastric packing with epiploic material by means of transgastric traction. The solution proved to be successful for short-term recovery. The underlying condition was not focused on, the patient being directed to the Oncology Department. Acute gastric perforation is a rare complication of gastric cancer, and the association with gastric linitis is uncommon. This specific histopathological condition made the classical surgical repair techniques unsuitable for the presented case and an atypical solution had to be performed.

[Tryptophan immunoadsorption for multiple sclerosis and neuromyelitis optica: therapy option for acute relapses during pregnancy and breastfeeding]

BACKGROUND

Approximately 25 % of women with multiple sclerosis (MS) suffer clinically relevant relapses during pregnancy. Almost all disease-modifying drugs are contraindicated in pregnancy. High-dose glucocorticoids have some serious risks, especially within the first trimester. Tryptophan immunoadsorption (IA) provides a safe option to treat MS relapses during pregnancy.

OBJECTIVES

In this case series we describe for the first time the use of tryptophan IA for MS and neuromyelitis optica (NMO) relapses during pregnancy and breastfeeding.

PATIENTS AND METHODS

In this study a total of 9 patients were retrospectively analyzed of which 7 patients received IA treatment during pregnancy, 2 during breastfeeding and 4-6 tryptophan IA treatments were performed per patient with the single use tryptophan adsorber. Primary outcome was symptom improvement of the relapse.

RESULTS

In this study four patients with MS and one with NMO relapse during pregnancy were treated with IA without preceding glucocorticoid pulse therapy. The MS patients showed improvement in the expanded disability status scale (EDSS) by at least one point, the NMO patient showed significant improvement in visual acuity and two pregnant patients with steroid-refractory relapses showed clinically relevant improvement after IA. Of the patients two suffered from steroid-refractory relapses during breastfeeding and relapse symptoms improved in both cases after treatment with IA. All treatments were well tolerated and no serious adverse events occurred.

CONCLUSION

Tryptophan IA was found to be safe, well-tolerated and effective in the treatment of MS and NMO relapses during pregnancy and breastfeeding, sometimes without preceding glucocorticoid pulse therapy. A binding recommendation is limited without prospective clinical studies.

Dissociable spatial and non-spatial attentional deficits after circumscribed thalamic stroke

Thalamic nuclei act as sensory, motor and cognitive relays between multiple subcortical areas and the cerebral cortex. They play a crucial role in cognitive functions such as executive functioning, memory and attention. In the acute period after thalamic stroke attentional deficits are common. The precise functional relevance of specific nuclei or vascular sub regions of the thalamus for attentional sub functions is still unclear. The theory of visual attention (TVA) allows the measurement of four independent attentional parameters (visual short term memory storage capacity (VSTM), visual perceptual processing speed, selective control and spatial weighting). We combined parameter-based assessment based on TVA with lesion symptom mapping in standard stereotactic space in sixteen patients (mean age 41.2 ± 11.0 SD, 6 females), with focal thalamic lesions in the medial (N = 9), lateral (N = 5), anterior (N = 1) or posterior (N = 1) vascular territories of the thalamus. Compared with an age-matched control group of 52 subjects (mean age 40.1 ± 6.4, 35 females), the patients with thalamic lesions were, on the group level, mildly impaired in visual processing speed and VSTM. Patients with lateral thalamic lesions showed a deficit in processing speed while all other TVA parameters were within the normal range. Medial thalamic lesions can be associated with a spatial bias and extinction of targets either in the ipsilesional or the contralesional field. A posterior case with a thalamic lesion of the pulvinar replicated a finding of Habekost and Rostrup (2006), demonstrating a spatial bias to the ipsilesional field, as suggested by the neural theory of visual attention (NTVA) (Bundesen, Habekost, & Kyllingsbæk, 2011). A case with an anterior-medial thalamic lesion showed reduced selective attentional control. We conclude that lesions in distinct vascular sub regions of the thalamus are associated with distinct attentional syndromes (medial = spatial bias, lateral = processing speed).

TMS over the right precuneus reduces the bilateral field advantage in visual short term memory capacity

BACKGROUND

Several studies have demonstrated a bilateral field advantage (BFA) in early visual attentional processing, that is, enhanced visual processing when stimuli are spread across both visual hemifields. The results are reminiscent of a hemispheric resource model of parallel visual attentional processing, suggesting more attentional resources on an early level of visual processing for bilateral displays [e.g. Sereno AB, Kosslyn SM. Discrimination within and between hemifields: a new constraint on theories of attention. Neuropsychologia 1991;29(7):659-75.]. Several studies have shown that the BFA extends beyond early stages of visual attentional processing, demonstrating that visual short term memory (VSTM) capacity is higher when stimuli are distributed bilaterally rather than unilaterally.

OBJECTIVE/HYPOTHESIS

Here we examine whether hemisphere-specific resources are also evident on later stages of visual attentional processing.

METHODS

Based on the Theory of Visual Attention (TVA) [Bundesen C. A theory of visual attention. Psychol Rev 1990;97(4):523-47.] we used a whole report paradigm that allows investigating visual attention capacity variability in unilateral and bilateral displays during navigated repetitive transcranial magnetic stimulation (rTMS) of the precuneus region.

RESULTS

A robust BFA in VSTM storage capacity was apparent after rTMS over the left precuneus and in the control condition without rTMS. In contrast, the BFA diminished with rTMS over the right precuneus.

CONCLUSION

This finding indicates that the right precuneus plays a causal role in VSTM capacity, particularly in bilateral visual displays.

Long-Term Effects of Serial Anodal tDCS on Motion Perception in Subjects with Occipital Stroke Measured in the Unaffected Visual Hemifield

Transcranial direct current stimulation (tDCS) is a novel neuromodulatory tool that has seen early transition to clinical trials, although the high variability of these findings necessitates further studies in clinically relevant populations. The majority of evidence into effects of repeated tDCS is based on research in the human motor system, but it is unclear whether the long-term effects of serial tDCS are motor-specific or transferable to other brain areas. This study aimed to examine whether serial anodal tDCS over the visual cortex can exogenously induce long-term neuroplastic changes in the visual cortex. However, when the visual cortex is affected by a cortical lesion, up-regulated endogenous neuroplastic adaptation processes may alter the susceptibility to tDCS. To this end, motion perception was investigated in the unaffected hemifield of subjects with unilateral visual cortex lesions. Twelve subjects with occipital ischemic lesions participated in a within-subject, sham-controlled, double-blind study. MRI-registered sham or anodal tDCS (1.5 mA, 20 min) was applied on five consecutive days over the visual cortex. Motion perception was tested before and after stimulation sessions and at 14- and 28-day follow-up. After a 16-day interval an identical study block with the other stimulation condition (anodal or sham tDCS) followed. Serial anodal tDCS over the visual cortex resulted in an improvement in motion perception, a function attributed to MT/V5. This effect was still measurable at 14- and 28-day follow-up measurements. Thus, this may represent evidence for long-term tDCS-induced plasticity and has implications for the design of studies examining the time course of tDCS effects in both the visual and motor systems.

Age-related changes in visual exploratory behavior in a natural scene setting

Diverse cognitive functions decline with increasing age, including the ability to process central and peripheral visual information in a laboratory testing situation (useful visual field of view). To investigate whether and how this influences activities of daily life, we studied age-related changes in visual exploratory behavior in a natural scene setting: a driving simulator paradigm of variable complexity was tested in subjects of varying ages with simultaneous eye- and head-movement recordings via a head-mounted camera. Detection and reaction times were also measured by visual fixation and manual reaction. We considered video computer game experience as a possible influence on performance. Data of 73 participants of varying ages were analyzed, driving two different courses. We analyzed the influence of route difficulty level, age, and eccentricity of test stimuli on oculomotor and driving behavior parameters. No significant age effects were found regarding saccadic parameters. In the older subjects head-movements increasingly contributed to gaze amplitude. More demanding courses and more peripheral stimuli locations induced longer reaction times in all age groups. Deterioration of the functionally useful visual field of view with increasing age was not suggested in our study group. However, video game-experienced subjects revealed larger saccade amplitudes and a broader distribution of fixations on the screen. They reacted faster to peripheral objects suggesting the notion of a general detection task rather than perceiving driving as a central task. As the video game-experienced population consisted of younger subjects, our study indicates that effects due to video game experience can easily be misinterpreted as age effects if not accounted for. We therefore view it as essential to consider video game experience in all testing methods using virtual media.

Driving simulation in the clinic: testing visual exploratory behavior in daily life activities in patients with visual field defects

Patients suffering from homonymous hemianopia after infarction of the posterior cerebral artery (PCA) report different degrees of constraint in daily life, despite similar visual deficits. We assume this could be due to variable development of compensatory strategies such as altered visual scanning behavior. Scanning compensatory therapy (SCT) is studied as part of the visual training after infarction next to vision restoration therapy. SCT consists of learning to make larger eye movements into the blind field enlarging the visual field of search, which has been proven to be the most useful strategy¹, not only in natural search tasks but also in mastering daily life activities². Nevertheless, in clinical routine it is difficult to identify individual levels and training effects of compensatory behavior, since it requires measurement of eye movements in a head unrestrained condition. Studies demonstrated that unrestrained head movements alter the visual exploratory behavior compared to a head-restrained laboratory condition³. Martin et al.⁴ and Hayhoe et al.⁵ showed that behavior demonstrated in a laboratory setting cannot be assigned easily to a natural condition. Hence, our goal was to develop a study set-up which uncovers different compensatory oculomotor strategies quickly in a realistic testing situation: Patients are tested in the clinical environment in a driving simulator. SILAB software (Wuerzburg Institute for Traffic Sciences GmbH (WIVW)) was used to program driving scenarios of varying complexity and recording the driver's performance. The software was combined with a head mounted infrared video pupil tracker, recording head- and eye-movements (EyeSeeCam, University of Munich Hospital, Clinical Neurosciences).

The positioning of the patient in the driving simulator and the positioning, adjustment and calibration of the camera is demonstrated. Typical performances of a patient with and without compensatory strategy and a healthy control are illustrated in this pilot study. Different oculomotor behaviors (frequency and amplitude of eye- and head-movements) are evaluated very quickly during the drive itself by dynamic overlay pictures indicating where the subjects gaze is located on the screen, and by analyzing the data. Compensatory gaze behavior in a patient leads to a driving performance comparable to a healthy control, while the performance of a patient without compensatory behavior is significantly worse. The data of eye- and head-movement-behavior as well as driving performance are discussed with respect to different oculomotor strategies and in a broader context with respect to possible training effects throughout the testing session and implications on rehabilitation potential.

Lipopolysaccharide binding protein (L.B.P.)--an inflammatory marker of prognosis in the acute appendicitis

LIPOPOLYSACCHARIDE BINDING PROTEIN (LBP) is an important mediator of the inflammatory reaction. A multitude of factors can determine the genic transcription activation and the increase of the LBP in the blood and the human body humours: Il1, Il 6, lipopolysaccharides, Gram-negative bacteria, as well as non-infectious agents. This paper is a prospective study performed on 147 patients admitted for acute appendicitis in 2010-2012 and evaluates the dynamics of LBP in acute appendicitis, by identifying the correlations between the pre- and post-operatory levels of LBP (up to 72 hours after surgery) and the anatomopathological type (i.e. catarrhal, phlegmonous and gangrenous). The mean pre-op LBP values are significantly different as to the histopathological result (p<0,005). Among the biological inflammatory markers measured in this present study, LBP has a dynamics of its own in the catarrhal and phlegmonous appendicitis. Thus, if after the surgical removal of the infectious source, the leukocites and neutrophiles decrease 72 hrs after surgery, LBP continues an ascending curve. The importance of this study consists in the introduction of last generation LBP-type inflammatory markers' dosage in the cecal appendix pathology. This implementation is brand new in the Romanian surgical practice. The good correlation between the LBP pre-op values and the histopathological diagnosis of the appendicits form that we discovered during the present study opens the way to large-scale use of the biochemical dosage of LBP in the management of acute appendicitis.

Excitability changes in the visual cortex quantified with signal detection analysis

PURPOSE

TDCS can increase excitability in the visual cortex. It is a matter of current debate if tDCS can improve visual performance. Promising parameters to measure detection sensitivity may be those of the signal detection theory ( = SDT), as it allows differentiating between response bias and detection sensitivity changes. The measure of detection sensitivity can be used to predict actual performance under a wide variety of different response criteria.

METHODS

Here we test if the SDT can quantify tDCS-induced effects in a visual contrast discrimination task in healthy subjects.

RESULTS

Anodal stimulation of the visual cortex improved performance, as calculated by detection sensitivity for stimuli presented in the center of the visual field. More peripheral locations in the visual field were unaffected by anodal stimulation. Cathodal stimulation and sham stimulation of the visual cortex had no consistent effect on detection sensitivity. The response bias was not affected by any type of stimulation.

CONCLUSIONS

Neuroplastic changes in the visual cortex induced by anodal tDCS can be measured by SDT, suggesting SDT could prospectively be a useful approach for monitoring restorative tDCS-effects on visual function in patients with central visual deficits.

Bulking control by low-dose ozonation of returned activated sludge in a full-scale wastewater treatment plant

Sludge bulking is still a problem in the operation of state-of-the-art wastewater treatment plants (WWTPs). The ozonation of returned activated sludge (RAS) is an innovative option as a non-specific measure for the control of filament growth. The applicability of sludge ozonation for bulking control of a large wastewater treatment plant was investigated. At a full-scale WWTP one lane was equipped with a sludge ozonation plant for RAS. The implemented sludge ozonation of RAS was tested against the two identical references lanes of the same WWTP. The positive effect on settleability could be clearly proven. Low-dose sludge ozonation could be a technical alternative in comparison with the established chemical measures for bulking control.

[Clinical and morphological features in a case of recent gastric carcinoma (the signet ring cell carcinoma type)]

The article presents the case of a male patient, hospitalized due to severe pain in the upper abdomen area, nausea, and vomiting. The patient was diagnosed with surgical acute abdomen, for which emergency surgery is performed. Upon penetration into the peritoneal cavity, stomach inspection shows at the medio-gastric level, on the greater curvature, a callous gastric ulcer, with a central perforation. A large excision is decided up to the healthy (normal) gastric tissue, and the resulting pieces are sent to the pathological anatomy laboratory. The histopathological exam reveals signet ring cell recent gastric carcinoma. The biopsy performed 1 month after surgery, prelevated from the antropyloric zone, reveals antropyloric gastritis with moderate activity and Helicobacter pylori positive. Due to the fact that such cases when this gastric cancer type is diagnosed in recent stages are extremely rare, we considered it useful to present it and look into its macroscopic and microscopic aspects, as well as into the differentiating diagnosis.

Light-Emitting Diodes Based on Conjugated Polymers: Control of Colour and Efficiency

Studies of the effect of different electrode combinations on the device characteristics of simple three layer light-emitting diodes (LEDs) prepared with poly(ρ-phenylenevinylene) (PPV) as the emissive layer sandwiched between two metal contacts have shown that it is generally more difficult to inject electrons than holes. In order to improve the efficiency of such devices it is, therefore, necessary to develop methods to enhance the injection of electrons and we illustrate here one example where we have successfully achieved this by the introduction of a further, electron transport, layer. The result is an eight fold increase in efficiency over our best three layer PPV devices. The efficiency is also dependent on the details of the polymer electronic structure and using a family of copolymers we have been able to produce enhancements in efficiency to values of up to 30 times that of the corresponding PPV devices. Variations in the polymer electronic structure also affect the colour of emission and the same family of copolymers allow control of emission colour from blue/green to orange/red. Supramolecular control of the copolymer electronic structure can be achieved by lithographic patterning and we show that it is possible to produce regions within a single polymer film that possess different π-π* energy gaps.

The Synthesis And Optoelectronic Properties Of Oxadiazole-Based Polymers

New oxadiazole-based polymeric materials have been synthesized either as side chain copolymers with polymethacrylate or as main chain copolymers carrying solubilizing elements such as hexafluoropropylidene or meta-linked aromatic spacer units. Many of these materials exhibit blue luminescence in the solid state. The materials have been evaluated by photoluminescence and cyclic voltammetry studies, and as the electron transporting layer in a two-layer electroluminescent device with poly(p-phenylenevinylene) (PPV) as the emissive layer. The major conclusion is that these materials function by providing large heterojunction offsets at the Highest Occupied Molecular Orbital (HOMO) which block the passage of holes through the device.