dti-of-the-visual-pathway-white-matter-tracts-and-cerebral-lesions

DTI of the Visual Pathway - White Matter Tracts and Cerebral Lesions

DTI is a technique that identifies white matter tracts (WMT) non-invasively in healthy and non-healthy patients using diffusion measurements. Similar to ...

Centre Hospitalier de Luxembourg

Cerebral vasospasm (VSP) is one of the most important risk factors for the development of a delayed neurological deficit after subarachnoid hemorrhage (SAH). Perfusion-weighted magnetic resonance imaging (pwMRI) provides the possibility of detecting tissue at risk for infarction. The objective of our study was to evaluate the feasibility and impact of pwMRI in the management of SAH patients.

Perfusion-weighted magnetic resonance imaging in patients with vasospasm: a useful new tool in the management of patients with subarachnoid hemorrhage.

The authors describe a 58-year-old man with sudden onset of a unilateral tremor caused by a midbrain lesion that affected the substantia nigra and the cerebellothalamic pathway. There were also clinical and neuroimaging signs of a communicating chronic hydrocephalus. The patient was severely handicapped by this tremor, which was a typical Holmes tremor with rest, posture, and intention components. Parkinson disease or multiple-system atrophy as causes for the tremor could be ruled out by DaTSCAN and 123I iodobenzamide and single-photon emission computerized tomography (SPECT), respectively. The tremor was completely supressed by temporary and permanent cerebrospinal fluid release after ventriculoperitoneal shunt placement, without any additional medication, for a period of 6 months. Afterward, the tremor returned, and the patient had to be treated by a stereotactic electrode implantation in the contralateral ventralis intermedius nucleus, which led to complete tremor suppression during the 1.5-year follow-up period. In this case report, the authors present the clinical description and the electrophysiological, SPECT, and magnetic resonance imaging data of a rare combination of symptoms and their surgical treatment.

Unilateral Holmes tremor, clearly responsive to cerebrospinal fluid release, in a patient with an ischemic midbrain lesion and associated chronic hydrocephalic ventricle enlargement. Case report.

[Attitude to urinary incontinence in women--a review of the literature: understanding different points of view].

Deep brain stimulation (DBS) is widely accepted in the treatment of advanced Parkinson's disease (PD) and other movement disorders. The standard implantation procedure is performed under local anesthesia (LA). Certain groups of patients may not be eligible for surgery under LA because of clinical reasons, such as massive fear, reduced cooperativity, or coughing attacks. Microrecording (MER) has been shown to be helpful in DBS surgery. The purpose of this study was to evaluate the feasibility of MER for DBS surgery under general anesthesia (GA) and to compare the data of intraoperative MER as well as the clinical data with that of the current literature of patients undergoing operation under LA.

Implantation of electrodes for deep brain stimulation of the subthalamic nucleus in advanced Parkinson's disease with the aid of intraoperative microrecording under general anesthesia.

Pressure ulcers are still a common health problem. Prevention and therapy of pressure ulcers require extensive nursing resources. Based on epidemiological data the use of preventive interventions and devices in hospital patients at risk was analysed. One object of this study was to compare the nursing practice with the recommendations given by a national practice guideline about pressure ulcer prevention by the German Network for Quality Development in Nursing (DNQP). Since 2002 each year a study has been conducted in order to investigate the prevalence of pressure ulcers in German hospitals. For the present study data of 9159 patients at pressure ulcer risk collected in three years (from 2002 to 2004) were analysed.

[Pressure ulcer prevention in German hospitals. An analysis of nursing practice with regard to guideline recommendations].

Over the past decade, deep brain stimulation (DBS) has become an effective treatment option for managing severe Parkinson's disease (PD). However, evidence is accumulating that DBS of target sites like the subthalamic nucleus (STN) can result in unintended cognitive effects that lie beyond motor control. The aim of the present study was to evaluate whether changes in executive task performance after chronic DBS might be predominantly associated with the stimulation of only one hemisphere. Eight patients with PD who had undergone DBS treatment of the STN were selected to participate in the study. Using a repeated measurements design, they underwent a neuropsychological examination under unilateral left- and right-sided stimulation in order to investigate laterality effects in their performance on the Wisconsin Card Sorting Test. All patients showed a significant improvement in motor symptoms postoperatively. Selected aspects of executive task performance were compromised under left- when compared to right-sided stimulation. Performance measures were unrelated to demographic, neurological, and behavioral characteristics of the patients. Findings are consistent with the emerging evidence that the STN is not only involved in motor control, but also participates in functions of the cognitive domain. Moreover, results raise the possibility that the left and right hemisphere might differ in their vulnerability to tolerate side effects on executive functions of DBS treatment. Potential consequences for future research questions and the management of cognitive side effects are discussed.

Impaired performance on the Wisconsin Card Sorting Test under left- when compared to right-sided deep brain stimulation of the subthalamic nucleus in patients with Parkinson's disease.

Tensor analysis of diffusion weighted magnetic resonance images is increasingly used for non-invasive tracking of nerve fibers in the human brain. Diffusion-tensor imaging (DTI) enables in-vivo research on the internal structure of the central nervous system, encompassing interconnection of functional areas, correlation between fiber deformations and certain disease patterns, as well as brain tumor localization. But the modeling of the local diffusion parameters is a computationally expensive part of the processing pipeline, resulting to run times up to days on standard desktop computers. A grid implementation of the algorithm with slice based parallelization reduces the processing down to 10% compared to a local cluster and 20% compared to sequential processing on the grid. A workflow implementation enables fault-tolerant handling of temporary failures within the grid. Furthermore, pure web-based access to the grid application allows for collaborative utilization even from protected infrastructures, as they are typically found in clinical environments.

Enabling of grid based diffusion tensor imaging using a workflow implementation of FSL.

A manufacturing and purification process for duplex oligonucleotides was established, which shortens and simplifies currently used procedures, yielding a product of higher purity. The reported procedure is based on nondenaturing anion-exchange (AEX) chromatography, which is performed on the annealed duplex rather than the individual single strands. The duplex is formed early in the process by annealing of the crude single strands directly after solid-phase synthesis. Two 30 μmol manufacturing runs using duplex purification were performed on 2 different AEX resins and compared with a manufacturing run of the same scale using conventional single-strand chromatography. The same pooling strategy was employed for all purifications. Content of optimal duplex (duplex exclusively comprising full-length single strands) was 90.5% and 90.2% for the batches obtained by duplex purification and 86.1% for the batch obtained by single-strand purification. Maximum chromatographic recoveries were 67% for the duplex purification and 68% for the single-strand purification. Hence, the manufacture of small interfering RNA (siRNA) using duplex purification was simpler and faster than conventional single-strand purification and provided better purity and similar yield of final siRNA.

Purification of small interfering RNA using nondenaturing anion-exchange chromatography.

Glioblastoma patients should be provided with a professional health care system that helps reduce their psychosocial burden. The aim of this study was to identify patients in need of psychosocial intervention. In addition, it was examined whether physicians' assessments adequately address the burden patients are under and their need for intervention. During their visit to one of two neurosurgery outpatient departments, n = 49 glioblastoma patients filled out the short version of the Hornheider questionnaire (HFK). Consulting physicians also rated their patients' burdens in a specially adapted version of the questionnaire (HFK-F). The results of the psychometric evaluation with both instruments were satisfactory. The majority of the patients (76 %) were identified as in need of psychosocial intervention. All of them were correctly categorized with the physicians' ratings. Physicians overestimated some aspects of the patients' burden, particularly in regard to their problems with relaxing and fear of living with the illness. The patients' ratings concerning the quality of the information physicians provided and their overall state of health only corresponded with the physicians' ratings in roughly half of the cases.

[Burden and need for psychosocial intervention of glioblastoma patients].

Clinical nursing education in Germany has not received attention in nursing science and practice for a long time, as it often seems to be a more or less "formalized appendix" of nursing education. Several development projects of clinical education taking place are mainly focused on the qualification of clinical preceptors. However, the clinical context and its influence on learning processes have still not been sufficiently investigated. The aim of this study was the testing of a German version of the clinical learning environment and supervision and nurse teacher scale (CLES + T scale). The sample of the pilot study consists of first-, second- and third-year student nurses (n=240) of a university nursing school from January to March 2011. Psychometric testing of the instrument is carried out by selected methods of classical testing theories using SPPS 19. The results show transferability of all subcategories of the CLES + T scale in the non-academic nursing education system of a university hospital in Germany, without the teacher scale. The strongest factor is "supervisory relationship". The German version of the CLES + T scale may help to evaluate and compare traditional and new models in clinical nursing education.

Evaluating students' perception of their clinical placements - testing the clinical learning environment and supervision and nurse teacher scale (CLES + T scale) in Germany.

Deep brain stimulation (DBS) is highly successful in treating Parkinson's disease (PD), dystonia, and essential tremor (ET). Until recently implantable neurostimulators were nonrechargeable, battery-driven devices, with a lifetime of about 3-5 years. This relatively short duration causes problems for patients (e.g. programming and device-use limitations, unpredictable expiration, surgeries to replace depleted batteries). Additionally, these batteries (relatively large with considerable weight) may cause discomfort. To overcome these issues, the first rechargeable DBS device was introduced: smaller, lighter and intended to function for 9 years.

A new rechargeable device for deep brain stimulation: a prospective patient satisfaction survey.

The identification and significance of cancer stem-like cells in malignant gliomas remains controversial. It has been proposed that cancer stem-like cells display increased drug resistance, through the expression of ATP-binding cassette transporters that detoxify cells by effluxing exogenous compounds. Here, we investigated the 'side population' phenotype based on efflux properties of ATP-binding cassette transporters in freshly isolated human glioblastoma samples and intracranial xenografts derived thereof. Using fluorescence in situ hybridization analysis on sorted cells obtained from glioblastoma biopsies, as well as human tumour xenografts developed in immunodeficient enhanced green fluorescence protein-expressing mice that allow an unequivocal tumour-stroma discrimination, we show that side population cells in human glioblastoma are non-neoplastic and exclusively stroma-derived. Tumour cells were consistently devoid of efflux properties regardless of their genetic background, tumour ploidy or stem cell associated marker expression. Using multi-parameter flow cytometry we identified the stromal side population in human glioblastoma to be brain-derived endothelial cells with a minor contribution of astrocytes. In contrast with their foetal counterpart, neural stem/progenitor cells in the adult brain did not display the side population phenotype. Of note, we show that CD133-positive cells often associated with cancer stem-like cells in glioblastoma biopsies, do not represent a homogenous cell population and include CD31-positive endothelial cells. Interestingly, treatment of brain tumours with the anti-angiogenic agent bevacizumab reduced total vessel density, but did not affect the efflux properties of endothelial cells. In conclusion our findings contribute to an unbiased identification of cancer stem-like cells and stromal cells in brain neoplasms, and provide novel insight into the complex issue of drug delivery to the brain. Since efflux properties of endothelial cells are likely to compromise drug availability, transiently targeting ATP-binding cassette transporters may be a valuable therapeutic strategy to improve treatment effects in brain tumours.

Side population in human glioblastoma is non-tumorigenic and characterizes brain endothelial cells.

Computer aided Planning and Navigation for Patient-Specific Deep Brain Stimulation.

Glioblastoma (GBM) is known to be a heterogeneous disease; however, the genetic composition of the cells within a given tumour is only poorly explored. In the advent of personalised medicine the understanding of intra-tumoural heterogeneity at the cellular and the genetic level is mandatory to improve treatment and clinical outcome. By combining ploidy-based flow sorting with array-comparative genomic hybridization we show that primary GBMs present as either mono- or polygenomic tumours (64 versus 36%, respectively). Monogenomic tumours were limited to a pseudodiploid tumour clone admixed with normal stromal cells, whereas polygenomic tumours contained multiple tumour clones, yet always including a pseudodiploid population. Interestingly, pseudodiploid and aneuploid fractions carried the same aberrations as defined by identical chromosomal breakpoints, suggesting that evolution towards aneuploidy is a late event in GBM development. Interestingly, while clonal heterogeneity could be recapitulated in spheroid-based xenografts, we find that genetically distinct clones displayed different tumourigenic potential. Moreover, we show that putative cancer stem cell markers including CD133, CD15, A2B5 and CD44 were present on genetically distinct tumour cell populations. These data reveal the clonal heterogeneity of GBMs at the level of DNA content, tumourigenic potential and stem cell marker expression, which is likely to impact glioma progression and treatment response. The combined knowledge of intra-tumour heterogeneity at the genetic, cellular and functional level is crucial to assess treatment responses and to design personalized treatment strategies for primary GBM.

Frank Hertel

National Service of Neurosurgery

Centre Hospitalier de Luxembourg

DTI of the Visual Pathway - White Matter Tracts and Cerebral Lesions

Frank Hertel

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}National Service of Neurosurgery

Centre Hospitalier de Luxembourg

DTI of the Visual Pathway - White Matter Tracts and Cerebral Lesions

National Service of Neurosurgery