What next after failed septal ventricular tachycardia ablation?

Ablation of ventricular tachycardia (VT) by conventional radiofrequency ablation can be impossible if the ventricular wall at the targeted ablation site is very thick, as for example the ventricular septum. We present a case of a patient with incessant, non-sustained slow VT originating from the septal part of the lower outflow tracts. Radiofrequency catheter ablation from both ventricles as well as from the anterior cardiac vein were not successful. Both high power radiofrequency ablation and bipolar radiofrequency ablation neither were successfull. Finally, ethanol ablation of the first septal perforator successfully terminated arrhythmia. We discuss the possibilities to overcome failed conventional radiofrequency VT ablation of a septal focus.

Radiofrequency ablation of multiple accessory pathways

The aim of the study was to review the clinical and electrophysiological characteristics and results of radiofrequency catheter ablation in patients with multiple accessory pathways to compare them with those of patients with single accessory pathways. Electrophysiological study and radiofrequency catheter ablation were performed in 1010 consecutive cases with Wolff Parkinson White Syndrome. Presence of multiple accessory pathways was documented in 31 patients (3.1%); 30 had two, and 1 had three accessory pathways. Of the 63 accessory pathways, 42 were manifest and 21 concealed. Nine patients had Ebstein's anomaly associated with atrioventricular bypass tracts. The most common combination was right posteroseptal with right free wall bypass tracts (15 patients with 30 accessory pathways). Fifty-one of the sixty-three accessory pathways (81%) were ablated successfully without complications. The duration of the procedure was 100 +/- 58 min and the fluoroscopic time 40 +/- 17 min. A follow up of 5 +/- 3 years after ablation, demonstrated recurrences of six accessory pathways (9.5%). In conclusion, patients with multiple accessory pathways can be treated by radiofrequency ablation in only one session with a high success rate although slightly less than that in patients with a single accessory pathway (81% vs 93%, P<0.01).

White matter in aphasia: a historical review of the Dejerines' studies

The Objective was to describe the contributions of Joseph Jules Dejerine and his wife Augusta Dejerine-Klumpke to our understanding of cerebral association fiber tracts and language processing. The Dejerines (and not Constantin von Monakow) were the first to describe the superior longitudinal fasciculus/arcuate fasciculus (SLF/AF) as an association fiber tract uniting Broca's area, Wernicke's area, and a visual image center in the angular gyrus of a left hemispheric language zone. They were also the first to attribute language-related functions to the fasciculi occipito-frontalis (FOF) and the inferior longitudinal fasciculus (ILF) after describing aphasia patients with degeneration of the SLF/AF, ILF, uncinate fasciculus (UF), and FOF. These fasciculi belong to a functional network known as the Dejerines' language zone, which exceeds the borders of the classically defined cortical language centers. The Dejerines provided the first descriptions of the anatomical pillars of present-day language models (such as the SLF/AF). Their anatomical descriptions of fasciculi in aphasia patients provided a foundation for our modern concept of the dorsal and ventral streams in language processing.

How useful is the ultrastructural study of the cilia of the respiratory tract in the diagnosis of an immotile cilia syndrome?

The immotile cilia syndrome (ICS) comprises a range of congenital defects of the ciliary apparatus most probably transmitted by autosomal recessive inheritance. Because cilia occur mainly in the respiratory and genital tract, the clinical symptoms of ICS are most commonly chronic sinusitis, bronchitis, bronchiectasis and male sterility. The syndrome can be associated with a situs inversus and is then called Kartagener's syndrome. We studied the ciliary ultrastructure in airway biopsies of 5 patients suffering from chronic upper and lower respiratory tract infections. With the single exception of one female patient with confirmed ICS diagnosis (Kartagener's syndrome) the etiology of the recurrent infections was unknown. The following ciliary defects were observed: missing dynein arms, radial spoke defects, missing nexin links, microtubular transpositions, compound cilia, supernumerary, absent, or incomplete microtubules, lack of ciliary orientation and various abnormal patterns of microtubular arrangement. In no instance did a patient show only a single anomaly; defects were always combined. Missing dynein arms, radial spoke defects and microtubular transpositions have frequently been described as lesions specific for ICS. Whenever these lesions were found simultaneously in both the respiratory and genital tracts, their genetic origin cannot be doubted. In our confirmed ICS patient the outer dynein arms were not missing but were reduced in number and length in a large number of cilia. The biopsy was, however, obtained from the heavily infected maxillary sinus and it is known that inflammation can lead to a loss of dynein arms. In the light of our investigations and of a review of the published cases of ciliary anomalies, it is concluded that none of the above defects in itself is specific for ICS. They may all occur as secondary lesions or sporadically as varieties in otherwise healthy subjects. It therefore appears questionable whether ICS can be diagnosed from the ciliary ultrastructure of a single airway biopsy. Assessment of ICS cannot be based simply on the ultrastructural demonstration of a particular ciliary defect, but necessitates additional considerations particularly regarding the origin of the biopsy, the sampling procedures and quantitation of defects. It appears necessary to investigate samples from different parts of the airways and quantitatively analyze the prominent lesions.

Deficit actual tool use in schizophrenia is linked to structural alterations in key regions of planning and executing of tool use and connecting fibers

Introduction: Schizophrenia patients frequently suffer from complex motor abnormalities including fine and gross motor disturbances, abnormal involuntary movements, neurological soft signs and parkinsonism. These symptoms occur early in the course of the disease, continue in chronic patients and may deteriorate with antipsychotic medication. Furthermore gesture performance is impaired in patients, including the pantomime of tool use. Whether schizophrenia patients would show difficulties of actual tool use has not yet been investigated. Human tool use is complex and relies on a network of distinct and distant brain areas. We therefore aim to test if schizophrenia patients had difficulties in tool use and to assess associations with structural brain imaging using voxel based morphometry (VBM) and tract based spatial statistics (TBSS). Methode: In total, 44 patients with schizophrenia (DSM-5 criteria; 59% men, mean age 38) underwent structural MR imaging and performed the Tool-Use test. The test examines the use of a scoop and a hammer in three conditions: pantomime (without the tool), demonstration (with the tool) and actual use (with a recipient object). T1-weighted images were processed using SPM8 and DTI-data using FSL TBSS routines. To assess structural alterations of impaired tool use we first compared gray matter (GM) volume in VBM and white matter (WM) integrity in TBSS data of patients with and without difficulties of actual tool use. Next we explored correlations of Tool use scores and VBM and TBSS data. Group comparisons were family wise error corrected for multiple tests. Correlations were uncorrected (p < 0.001) with a minimum cluster threshold of 17 voxels (equivalent to a map-wise false positive rate of alpha < 0.0001 using a Monte Carlo procedure). Results: Tool use was impaired in schizophrenia (43.2% pantomime, 11.6% demonstration, 11.6% use). Impairment was related to reduced GM volume and WM integrity. Whole brain analyses detected an effect in the SMA in group analysis. Correlations of tool use scores and brain structure revealed alterations in brain areas of the dorso-dorsal pathway (superior occipital gyrus, superior parietal lobule, and dorsal premotor area) and the ventro-dorsal pathways (middle occipital gyrus, inferior parietal lobule) the action network, as well as the insula and the left hippocampus. Furthermore, significant correlations within connecting fiber tracts - particularly alterations within the bilateral corona radiata superior and anterior as well as the corpus callosum -were associated with Tool use performance. Conclusions: Tool use performance was impaired in schizophrenia, which was associated with reduced GM volume in the action network. Our results are in line with reports of impaired tool use in patients with brain lesions particularly of the dorso-dorsal and ventro-dorsal stream of the action network. In addition an effect of tool use on WM integrity was shown within fiber tracts connecting regions important for planning and executing tool use. Furthermore, hippocampus is part of a brain system responsible for spatial memory and navigation.The results suggest that structural brain alterations in the common praxis network contribute to impaired tool use in schizophrenia.

Listeria monocytogenes spreads within the brain by actin-based intra-axonal migration

Listeria monocytogenes rhombencephalitis is a severe progressive disease despite a swift intrathecal immune response. Based on previous observations, we hypothesized that the disease progresses by intra-axonal spread within the central nervous system. To test this hypothesis, neuroanatomical mapping of lesions, immunofluorescence analysis, and electron microscopy were performed on brains of ruminants with naturally occurring rhombencephalitis. In addition, infection assays were performed in bovine brain cell cultures. Mapping of lesions revealed a consistent pattern with a preferential affection of certain nuclear areas and white matter tracts, indicating that Listeria monocytogenes spreads intra-axonally within the brain along interneuronal connections. These results were supported by immunofluorescence and ultrastructural data localizing Listeria monocytogenes inside axons and dendrites associated with networks of fibrillary structures consistent with actin tails. In vitro infection assays confirmed that bacteria were moving within axon-like processes by employing their actin tail machinery. Remarkably, in vivo, neutrophils invaded the axonal space and the axon itself, apparently by moving between split myelin lamellae of intact myelin sheaths. This intra-axonal invasion of neutrophils was associated with various stages of axonal degeneration and bacterial phagocytosis. Paradoxically, the ensuing adaxonal microabscesses appeared to provide new bacterial replication sites, thus supporting further bacterial spread. In conclusion, intra-axonal bacterial migration and possibly also the innate immune response play an important role in the intracerebral spread of the agent and hence the progression of listeric rhombencephalitis.

Deep Into the Fibers! Postmortem Diffusion Tensor Imaging in Forensic Radiology.

PURPOSE In traumatic brain injury, diffusion-weighted and diffusion tensor imaging of the brain are essential techniques for determining the pathology sustained and the outcome. Postmortem cross-sectional imaging is an established adjunct to forensic autopsy in death investigation. The purpose of this prospective study was to evaluate postmortem diffusion tensor imaging in forensics for its feasibility, influencing factors and correlation to the cause of death compared with autopsy. METHODS Postmortem computed tomography, magnetic resonance imaging, and diffusion tensor imaging with fiber tracking were performed in 10 deceased subjects. The Likert scale grading of colored fractional anisotropy maps was correlated to the body temperature and intracranial pathology to assess the diagnostic feasibility of postmortem diffusion tensor imaging and fiber tracking. RESULTS Optimal fiber tracking (>15,000 fiber tracts) was achieved with a body temperature at 10°C. Likert scale grading showed no linear correlation (P > 0.7) to fiber tract counts. No statistically significant correlation between total fiber count and postmortem interval could be observed (P = 0.122). Postmortem diffusion tensor imaging and fiber tracking allowed for radiological diagnosis in cases with shearing injuries but was impaired in cases with pneumencephalon and intracerebral mass hemorrhage. CONCLUSIONS Postmortem diffusion tensor imaging with fiber tracking provides an exceptional in situ insight "deep into the fibers" of the brain with diagnostic benefit in traumatic brain injury and axonal injuries in the assessment of the underlying cause of death, considering influencing factors for optimal imaging technique.

Inseparable, incapable, or invisible: Why public organizations award no-bid contracts

No-bid contracting is a highly prevalent practice in public procurement of technology services. Alt-hough no-bid contracting is a substantial problem since it reduces competition and welfare, the litera-ture lacks theoretical explanations and empirical tests for why public organizations award no-bid con-tracts. In this paper, we propose three theoretical explanations for no-bid contracting, drawing on transaction cost economics, organizational learning, and institutional theory. We also present how we test these explanations using a comprehensive sample of public procurement transactions. We expect to contribute theoretical explanations for no-bid contracting and practical implications for policy-makers.

Findings in uteri and ovaries from Eringer cows, slaughtered due to fertility problems

Eringer cows are often slaughtered due to fertility problems which result from inflammatory and degenerative changes of the uterus or hormonal imbalances. Twenty-one genital tracts from Eringer cows suffering from fertility problems were collected in the abattoir. The purpose of the study was the macroscopic evaluation of the ovaries and the uterus followed by a histological and microbiological analysis of the uterus. Data from inseminations and calvings were provided by the Eringer breeding association and through the internet portal www.agate.ch. Median age of the cows was 6.9 years, number of calves per cow was 2.5 and median period between last calving and slaughter was 1.5 years. In 13 from 21 of the urogenital tracts examined, macroscopic abnormalities of the ovaries and/or histologic or microbiologic findings in the uterus could explain fertility-associated slaughter.

Microstructure and Cerebral Blood Flow within White Matter of the Human Brain: A TBSS Analysis.

BACKGROUND White matter (WM) fibers connect different brain regions and are critical for proper brain function. However, little is known about the cerebral blood flow in WM and its relation to WM microstructure. Recent improvements in measuring cerebral blood flow (CBF) by means of arterial spin labeling (ASL) suggest that the signal in white matter may be detected. Its implications for physiology needs to be extensively explored. For this purpose, CBF and its relation to anisotropic diffusion was analyzed across subjects on a voxel-wise basis with tract-based spatial statistics (TBSS) and also across white matter tracts within subjects. METHODS Diffusion tensor imaging and ASL were acquired in 43 healthy subjects (mean age = 26.3 years). RESULTS CBF in WM was observed to correlate positively with fractional anisotropy across subjects in parts of the splenium of corpus callosum, the right posterior thalamic radiation (including the optic radiation), the forceps major, the right inferior fronto-occipital fasciculus, the right inferior longitudinal fasciculus and the right superior longitudinal fasciculus. Furthermore, radial diffusivity correlated negatively with CBF across subjects in similar regions. Moreover, CBF and FA correlated positively across white matter tracts within subjects. CONCLUSION The currently observed findings on a macroscopic level might reflect the metabolic demand of white matter on a microscopic level involving myelination processes or axonal function. However, the exact underlying physiological mechanism of this relationship needs further evaluation.

Magnetic Resonance Imaging Finding in Small Ruminants with Brain

Brain disease is an important cause of neurologic deficits in small ruminants, however few MRI features have been described. The aim of this retrospective, case series study was to describe MRI characteristics in a group of small ruminants with confirmed brain disease. A total of nine small ruminants (six sheep and three goats) met inclusion criteria. All had neurologic disorders localized to the brain and histopathologic confirmation. In animals with toxic-metabolic diseases, there were bilaterally symmetric MRI lesions affecting either the gray matter (one animal with polioencephalomalacia) or the white matter (two animals with enterotoxemia). In animals with suppurative inflammation, asymmetric focal brainstem lesions were present (two animals with listeric encephalitis), or lesions typical of an intra-axial (one animal) or dural abscess (one animal), respectively. No MRI lesions were detected in one animal with suspected viral cerebellitis and one animal with parasitic migration tracts. No neoplastic or vascular lesions were identified in this case series. Findings from the current study supported the use of MRI for diagnosing brain diseases in small ruminants.