Extrahepatic bile ducts in healthy subjects,in patients with cholelithiasis,and in postcholecystectomy patients: A prospective ultrasonic study

To determine the average diameter and the upper normal limit of the common bile duct in healthy man, 830 blood donors were examined by ultrasound. The mean diameter was 2.5 ± 1.1 mm (SD) at the porta hepatis and 2.8 ± 1.2 mm (SD) at the widest point, the regression coefficient between both diameters being r = 0.84. None of the healthy subjects had a diameter larger than 7 mm at any site, and in 95% of all subjects the diameters were less than 4 mm at both sites of measurement. The diameters were significantly correlated with age (r = 0.16) and weight (r = 0.11), but not with sex, height, and body surface area. In 73 patients with cholelithiasis and in 55 patients after cholecystectomy, all of whom lacked clinical or laboratory signs of biliary obstruction, the average diameters at the porta hepatis were 3.8 ± 2.0 mm and 5.2 ± 2.3 mm, and at the widest point 4.8 ± 2.2 mm and 6.2 ± 2.5 mm, respectively. It is concluded that a common bile duct with any sonographic diameter larger than 4 mm should be followed closely and evaluated further with clinical examinations such as intravenous cholangiography unless cholecystectomy has been performed.     

Biomechanical investigation of two long bone growth modulation techniques by finite element simulations

Implants used to correct pathological varus–valgus deformities (VVD) and leg length discrepancies (LLD) may not be optimized for the specific treatment, as suggested by their off‐label use. Detailed analysis of this issue has been limited by the poorly understood mechanical behavior of the growing physis and ignorance of the loads acting on the implants. The aim of this study was to predict and compare the loading conditions of a growth modulation implant in VVD and LLD treatments. Idealized finite element (FE) models of the juvenile distal femur treated with the Eight‐Plate implant were developed for VVD and LLD. Bone growth was simulated using thermal strains. The axial force in the plate was compared between the two treatments. Case‐specific plate forces were predicted by virtually reproducing the screw deformation visible on radiographs of LLD (N = 4) and VVD (N = 4) clinical cases. The simple FE models reproduced the clinical implant deformations well. The resulting forces ranged from 129 to 580 N for the VVD patients. For LLD, this range was from 295 to 1002 N per plate, that is, 590–2004 N for the entire physis. The higher forces in LLD could be explained by restricted screw divergence in the double‐sided implant application. For the first time, the loading conditions of a growth modulation implant were investigated and compared between two treatments by FE analyses, and the range of case‐specific loads was predicted. These simulation tools may be utilized for guiding appropriate usage and for efficient development of implants. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1398–1405, 2018.

     

CT and MR imaging in Hodgkin's disease--present and future

Initial staging of Hodgkin's disease is crucial to determine the location and extent of disease, and is the hallmark for the choice of treatment. At present, the established radiological technique for staging Hodgkin's disease is computed tomography (CT). Modern multidetector row CT scanners allow fast imaging from the scull base to the groins during a single breath hold with a spatial resolution of approximately 1 mm. Both, nodal and extranodal involvement of Hodgkin's disease can be diagnosed with CT. Magnetic resonance (MR) imaging is another useful cross-sectional imaging modality for staging Hodgkin's disease. The development of fast MR imaging techniques has considerably reduced imaging time without compromising the quality of MR images. As a consequence, MR imaging is now considered to be as diagnostic as CT for staging Hodgkin's disease. The excellent soft-tissue contrast and the lack of exposure to ionizing radiation are the main advantages of MR imaging. For the detection of extranodal Hodgkin's disease, MR imaging is superior to assess involvement of the brain, the spinal cord and bone marrow; while CT allows excellent evaluation of lung disease. Common major problems in staging Hodgkin's disease are still the detection of nodal involvement in normal sized lymph nodes and residual tumor masses after therapy. In the future, newly developed lymphotropic contrast agents for MR imaging might be helpful to answer these questions.     

Ethnicity and dangerousness criteria for court ordered admission to a psychiatric hospital

Background  

Black and minority ethnic (BME) populations are disproportionately detained in psychiatric hospitals.     

Hemodynamic Changes in a Model of Chronic Heart Failure Induced by Multiple Sequential Coronary Microembolization in Sheep

Although a large variety of animal models for acute ischemia and acute heart failure exist, valuable models for studies on the effect of ventricular assist devices in chronic heart failure are scarce. We established a stable and reproducible animal model of chronic heart failure in sheep and aimed to investigate the hemodynamic changes of this animal model of chronic heart failure in sheep. In five sheep (n = 5, 77 ± 2 kg), chronic heart failure was induced under flouroscopic guidance by multiple sequential microembolization through bolus injection of polysterol microspheres (90 µm, n = 25.000) into the left main coronary artery. Coronary microembolization (CME) was repeated up to three times in 2 to 3‐week intervals until animals started to develop stable signs of heart failure. During each operation, hemodynamic monitoring was performed through implantation of central venous catheter (central venous pressure [CVP]), arterial pressure line (mean arterial pressure [MAP]), implantation of a right heart catheter {Swan‐Ganz catheter (mean pulmonary arterial pressure [PAPmean])}, pulmonary capillary wedge pressure (PCWP), and cardiac output [CO]) as well as pre‐ and postoperative clinical investigations. All animals were followed for 3 months after first microembolization and then sacrificed for histological examination. All animals developed clinical signs of heart failure as indicated by increased heart rate (HR) at rest (68 ± 4 bpm [base] to 93 ± 5 bpm [3 mo][P < 0.05]), increased respiratory rate (RR) at rest (28 ± 5 [base] to 38 ± 7 [3 mo][P < 0.05]), and increased body weight 77 ± 2 kg to 81 ± 2 kg (P < 0.05) due to pleural effusion, peripheral edema, and ascites. Hemodynamic signs of heart failure were revealed as indicated by increase of HR, RR, CVP, PAP, and PCWP as well as a decrease of CO, stroke volume, and MAP 3 months after the first CME. Multiple sequential intracoronary microembolization can effectively induce myocardial dysfunction with clinical and hemodynamic signs of chronic ischemic cardiomyopathy. The present model may be suitable in experimental work on heart failure and left ventricular assist devices, for example, for studying the impact of mechanical unloading, mechanisms of recovery, and reverse remodeling.     

Dyskinesia-induced postural instability in Parkinson's disease

Parkinson's disease (PD) patients may complain of unsteadiness and impaired balance not only when OFF, but also while being ON with levodopa-induced dyskinesia (LID), yet influence of LID upon postural stability has not been specifically examined. In this study, we addressed this issue using static and dynamic posturography in patients with advanced PD and typical LID. Relevant postural stability parameters were measured on force platforms when patients were OFF and ON, either in quiet standing or when performing leaning tasks designed to stress postural stability. Simultaneously, LID was assessed clinically using a dyskinesia rating scale of severity and subjective unsteadiness was computed. Displacement of the net center of pressure (COPnet), range of COPnet in the mediolateral and antero-posterior directions and 95% confidence ellipse area for both feet were measured as indicators of postural stability and used for comparison analyses. We found a significant increase of COPnet displacement in all tasks up to 556% (mean: 125+/-165%) when patients were ON with dyskinesia compared to the OFF state. In about half of the patients, this increase was marked and correlated with subjective unsteadiness while ON. There was a good correlation between the clinical scores of dyskinesia severity and most COPnet values. Patients demonstrated a tendency to sustain their weight on the foot less affected by dyskinesia, probably as a compensatory mechanism. Our results suggest that LID may compromise balance and independently contribute to postural instability in advanced PD.     

E-learning courses in epilepsy--concept, evaluation, and experience with the e-learning course "genetics of epilepsies"

PURPOSE: To evaluate the efficacy of the e-learning course "Genetics of Epilepsies" and to assess the experiences of the participants and e-moderators with this new approach. METHODS: Prospective, controlled study with waiting group (control group, n = 18) and e-learning group (n = 20). The control group got the same reference literature list as the e-learning group. Both groups were assessed twice: The e-learning group before and after the course; the control group was assessed at the same times. Primary outcome measure: increase in knowledge about genetics of epilepsies using questionnaires based on items formulated by experts (internal consistency, Cronbach's alpha = 0.86). Main hypothesis: greater increase of knowledge in the e-learning group compared to control group. Secondary outcome measures: assessment of the educational course and learning environment by participants and by tutors/e-moderators. RESULTS: Significant time x group interaction and group effect (ANOVA, each p < 0.01) with regard to knowledge. At baseline, the groups did not differ with respect to knowledge about genetics of epilepsy. In contrast to the control group, the increase of knowledge in the e-learning group was highly significant (p < 0.001). The majority of the participants of the e-learning course was content with their personal learning process (75% agree, 15% strongly agree). Most of them reported a gain in competence in the treatment and counseling of people with epilepsy (38.9% agree, 50% strongly agree). All participants would recommend this course to others and all but one participant are interested in other e-learning courses. CONCLUSION: The study indicates e-learning courses are an appropriate tool to improve knowledge of physicians in genetics of epilepsy.     

Hemineglect: take a look at the back space

Visual hemineglect, the failure to explore the half of space, real or imagined, contralateral to a cerebral lesion with respect to body or head, can be seen as an illustration of the brain's Euclidean representation of the left/right axis. Here we present two patients with left-sided neglect, in whom only the left hemispace in front of an imagined and/or real body position was inaccessible, but the space behind them remained fully represented. These observations suggest that of the three Euclidean dimensions (up/down, left/right, and front/back), at least the latter two are modularly and separately represented in the human brain.     

An architectural model of conscious and unconscious brain functions: Global Workspace Theory and IDA.

While neural net models have been developed to a high degree of sophistication, they have some drawbacks at a more integrative, "architectural" level of analysis. We describe a "hybrid" cognitive architecture that is implementable in neuronal nets, and which has uniform brainlike features, including activation-passing and highly distributed "codelets," implementable as small-scale neural nets. Empirically, this cognitive architecture accounts qualitatively for the data described by Baars' Global Workspace Theory (GWT), and Franklin's LIDA architecture, including state-of-the-art models of conscious contents in action-planning, Baddeley-style Working Memory, and working models of episodic and semantic longterm memory. These terms are defined both conceptually and empirically for the current theoretical domain. The resulting architecture meets four desirable goals for a unified theory of cognition: practical workability, autonomous agency, a plausible role for conscious cognition, and translatability into plausible neural terms. It also generates testable predictions, both empirical and computational.     

Hierarchies, multiple energy barriers, and robustness govern the fracture mechanics of alpha-helical and beta-sheet protein domains

The fundamental fracture mechanisms of biological protein materials remain largely unknown, in part, because of a lack of understanding of how individual protein building blocks respond to mechanical load. For instance, it remains controversial whether the free energy landscape of the unfolding behavior of proteins consists of multiple, discrete transition states or the location of the transition state changes continuously with the pulling velocity. This lack in understanding has thus far prevented us from developing predictive strength models of protein materials. Here, we report direct atomistic simulation that over four orders of magnitude in time scales of the unfolding behavior of alpha-helical (AH) and beta-sheet (BS) domains, the key building blocks of hair, hoof, and wool as well as spider silk, amyloids, and titin. We find that two discrete transition states corresponding to two fracture mechanisms exist. Whereas the unfolding mechanism at fast pulling rates is sequential rupture of individual hydrogen bonds (HBs), unfolding at slow pulling rates proceeds by simultaneous rupture of several HBs. We derive the hierarchical Bell model, a theory that explicitly considers the hierarchical architecture of proteins, providing a rigorous structure-property relationship. We exemplify our model in a study of AHs, and show that 3-4 parallel HBs per turn are favorable in light of the protein's mechanical and thermodynamical stability, in agreement with experimental findings that AHs feature 3.6 HBs per turn. Our results provide evidence that the molecular structure of AHs maximizes its robustness at minimal use of building materials.